JP4730774B2 - Electron emission device - Google Patents

Description

  The present invention includes an emitter portion made of a dielectric, a lower electrode formed at a lower portion of the emitter portion, and an upper electrode formed at an upper portion of the emitter portion so as to face the lower electrode across the emitter portion. And an electron emission device comprising:

Conventionally, various theories have been described in the following non-patent literature regarding emission of electrons from an emitter portion formed of a dielectric.
Yasuoka, Ishii, "Pulsed electron source using a ferroelectric cathode" Applied Physics Vol.68, No.5, p546-550 (1999) VFPuchkarev, GAMesyats, On the mechanism of emission from the ferroelectric ceramic cathode, J.Appl.Phys., Vol 78, No. 9, 1 November, 1995, p.5633-5637 H.Riege, Electron emissionferroelectrics-a review, Nuc1. Instr. And Meth.A340, p. 80-89 (1994)

  The present applicant has made various proposals regarding an electron emission device having an emitter portion made of such a dielectric. That is, the electron emission device proposed by the present applicant has the same emitter part made of a dielectric, a lower electrode formed under the emitter part, and the lower electrode across the emitter part. An upper electrode formed on the emitter. In this electron emission device, a driving voltage is applied between the lower electrode and the upper electrode. As a result, the polarization of the dielectric is reversed, and electrons are emitted from the fine through-hole formed in the upper electrode along with the polarization reversal.

  More specifically, the electron emission device 200 includes an upper electrode 204 and a lower electrode 206 formed on the upper surface and the lower surface of the emitter section 202, respectively, as shown in FIGS. A through hole 204 a is formed in the upper electrode 204. The surface of the through-hole 204a that faces the emitter section 202 is separated from the emitter section 202 by a predetermined distance.

  First, as shown in FIG. 45, the electron emission device 200 is in an initial state in which electrons are not accumulated on the upper portion (upper surface) of the emitter section 202. Next, as shown in FIG. 46, when a drive voltage is applied to the lower electrode 206 so that the potential of the upper electrode 204 becomes negative, the polarization of the emitter section 202 is inverted. Due to this polarization inversion, electrons are supplied from the upper electrode 204 toward the emitter section 202 that exists immediately below the periphery of the through hole 204 a of the upper electrode 204. As a result, electrons are accumulated in the upper part of the emitter part 202 that exists immediately below the peripheral part of the through hole 204a.

  Next, as shown in FIG. 47, when the drive voltage is applied to the lower electrode 206 so that the potential of the upper electrode 204 becomes positive, the polarization of the emitter section 202 is reversed again. If such a state continues, as shown in FIG. 48, the electrons accumulated in the upper portion of the emitter section 202 are emitted upward (Z-axis positive direction) through the through-hole 204a by the coulomb repulsive force. The

  By the way, in the electron emission device which has been proposed so far, it is generally difficult to form the through hole 204a having a very fine diameter in the upper electrode 204, and the diameter of the through hole 204a is extremely fine. The diameter of the through hole 204a is, for example, 100 nm or more because it is considered that the amount of electrons that can be supplied from the peripheral part of the through hole 204a to the upper part of the emitter part 202 is reduced.

  However, in order to increase the amount of electron emission per unit area of the upper surface of the electron emission device 200, the diameter of the through hole 204a is changed within a range of 100 nm or more, the number of the through holes 204a is increased, etc. Despite extensive studies, the amount of electron emission was limited.

  The reason why the amount of emitted electrons cannot be increased is that, as can be understood from the equipotential lines shown in FIG. 49, the equipotential lines bulge out from the through holes 204a, so that electrons are supplied from the periphery of the through holes 204a. Although it is likely to occur, it is presumed that it is difficult to accumulate in the vicinity immediately below the central portion of the through-hole 204a having a small electric field strength.

One of the objects of the electron-emitting device of the present invention is to solve the above problems and provide an electron-emitting device with a large amount of electron emission. An electron emission device according to the present invention is formed on an upper part of an emitter part made of a dielectric, a lower electrode formed at a lower part of the emitter part, and facing the lower electrode across the emitter part. It includes an upper electrode which is, and you emit electrons through the upper electrode from the emitter section by the driving voltage is applied between the lower electrode and the upper electrode. In this case, the upper electrode is a through hole that exposes the emitter section (e.g., the average size of the through-hole of its through hole is and less than 100nm or 10 nm) with provided with a plurality of, a in the circumferential portion of the through hole the emitter surface opposed to Te is that are formed as spaced apart by a predetermined distance from the emitter section.

  Here, the average diameter of the through-holes is equal to the diameter of the through-hole if the shape of the through-hole is circular, and is the length of a plurality of different line segments passing through the center of the through-hole if the shape of the through-hole is not circular. It is defined as the average. The shape of the through hole does not have to be a circle, and may be a triangle, an ellipse, an oval, a thin groove (slit shape), or the like. In addition, when the shape of the through hole is a thin groove shape, the average diameter of the portion that can be regarded as a substantially independent through hole may be treated as the average diameter of the through hole, and when the groove width is substantially constant, What is necessary is just to treat the average of a groove width as an average diameter of the said through-hole.

Further, in the electron-emitting device of the present invention, the average diameter of the through hole is not smaller than the particle size of the dielectric of the emitter section.

  A through-hole that does not include a grain boundary in the emitter portion (see a broken-line circle B in FIG. 4) immediately below a through-hole that includes the grain boundary in the emitter portion (see the broken-line circle A portion and the grain boundary 13a1 in FIG. 4). (See section) can emit more electrons. Therefore, if the average diameter of the through holes of the upper electrode is made smaller than the grain size of the dielectric that constitutes the emitter section, the number of through holes that do not include the grain boundary of the emitter section directly increases, so that more Electrons can be emitted. The diameter of the through-hole is 1/5 or less (more preferably 1/10 or less, more preferably 1/20 or less) of the particle diameter of the dielectric in order to increase the number of through-holes not including the grain boundary of the dielectric. It is good to do.

  The upper electrode contains a metal, and the through hole is a pore formed by metal crystal grains of the same metal (a space formed between metal crystal grains that are bonded to each other when the metal crystal grains are formed). It is preferable.

  The pores (through-holes) formed by the metal crystal grains are formed by applying and extending an organic metal compound on the upper surface of the substance serving as the emitter portion by a thick film forming method such as screen printing, spray coating, and dipping coating. It is formed by the method of baking by heating at the temperature. The surface of such a through hole (metal crystal grain surface) has higher metal crystallinity than the surface of the through hole formed by subsequent processing such as laser processing. Therefore, it is estimated that electron emission is likely to be performed. Moreover, the through-hole which has a metal crystal grain surface can be obtained by sintering a metal. Therefore, the electron emission device provided with the through hole having such a metal crystal grain surface does not have the damage of the emitter surface that occurs when the through hole is formed by processing such as laser processing. Further, if the upper electrode is provided with pores (through-holes) formed of metal crystal grains, there is an advantage that no fine shavings or the like of the electrode generated when the through-holes are formed by processing are generated.

  In this case, it is preferable that the upper electrode includes two or more kinds of metals.

  Further, the upper electrode is made of silver (Ag), gold (Au), iridium (Ir), rhodium (Rh), ruthenium (Ru), platinum (Pt), palladium (Pd), aluminum (Al), copper (Cu). ), Nickel (Ni), chromium (Cr), molybdenum (Mo), tungsten (W), and titanium (Ti), and particularly preferably platinum as a base material. . In addition, a base material means the component with the largest weight% among the metals which comprise an upper electrode.

  Furthermore, the upper electrode of the electron emission device according to the present invention is an electrode having a three-dimensional network structure formed by bonding metal particles. In other words, the upper electrode of the electron-emitting device according to the present invention is an electrode characterized in that it is a porous body formed by chemically bonding two or more metal particles in the thickness direction.

  By the way, if a gas exists in the space between the upper electrode and the emitter part, the gas is ionized during the electron emission operation and adsorbed on the upper electrode, and supply of electrons from the upper electrode to the emitter part and / or Alternatively, emission of electrons supplied and stored in the emitter section through the through hole of the upper electrode is inhibited.

  On the other hand, the above-described upper electrode of the three-dimensional network or porous body includes a large number of pores that communicate the space between the upper electrode and the emitter portion and the space above the upper electrode. Therefore, when the pressure is lowered so that the space above the upper electrode approaches a vacuum, the gas molecules remaining in the space between the upper electrode and the emitter are guided to the space above the upper electrode through the pores. It is burned. Thereby, the number of gas molecules remaining in the space between the upper electrode and the emitter can be reduced. As a result, an electron emission device in which the amount of electron emission is hardly reduced even when the electron emission operation is repeated is provided.

  In addition, the average aperture ratio of the upper electrode of the electron emission device according to the present invention is preferably 5% or more and 60% or less. The average aperture ratio is more preferably 10% or more and 60% or less, and further preferably 20% or more and 60% or less.

Such an electron emitter is
In a process including a temperature raising step in which an organometallic compound containing two or more kinds of metals extends in the form of a film over the substance serving as the emitter portion and then is heated to a predetermined temperature at a predetermined temperature increase rate. Then, the organic metal compound can be produced by a production method having a step of forming the upper electrode by firing. In the present specification, the “temperature increase rate” refers to “the temperature increase rate of the substance serving as the upper electrode”.

  Here, “organometallic compound containing two or more kinds of metals” is a mixture of two or more kinds of organometallic compounds containing only one kind of metal, one kind of organometallic compound containing two or more kinds of metals, and Any one of a mixture of one organometallic compound containing two or more metals and another organometallic compound may be used.

Also,
The organometallic compound containing two or more kinds of metals is mixed at a predetermined ratio with an organometallic compound containing a predetermined metal as a base material and an organometallic compound containing a metal having a melting point higher than that of the predetermined metal. Mixed organometallic compound
The step of forming the upper electrode is preferably a step of firing the mixed organometallic compound so that the two or more kinds of metals contained in the mixed organometallic compound exist in a single phase state. .

  According to this, compared with the case where an organometallic compound containing only one kind of a predetermined metal is fired, the presence of a metal having a high melting point makes it difficult for particle growth of two or more kinds of metals in a single phase to proceed. Therefore, it is possible to easily form an upper electrode having a through hole with a minute diameter of 10 nm or more and less than 100 nm.

on the other hand,
The organometallic compound containing two or more kinds of metals is prepared by mixing an organometallic compound containing a predetermined metal as a base material and an organometallic compound containing another metal different from the predetermined metal at a predetermined ratio. A mixed organometallic compound,
The step of forming the upper electrode is preferably a step of firing the mixed organometallic compound so that the two or more types of metals contained in the mixed organometallic compound are present in a mixed phase.

  According to this, the predetermined metal used as a base material and another metal form two or more different phases by heating, thereby inhibiting the grain growth of the metal constituting each phase. As a result, it is possible to form an upper electrode having a through hole with a minute diameter of 10 nm or more and less than 100 nm.

  Further, in the case of the firing method so that the two or more kinds of metals exist in a mixed phase state, the other metal is preferably a metal having a lower melting point than the predetermined metal serving as the base material. .

  According to this, since the temperature at the time of sintering the metal powder can be set to a temperature that is about the same as or lower than the temperature for sintering the predetermined single metal as the base material. The other parts such as the emitter are not thermally damaged, and the upper electrode is not weakened.

  Furthermore, in the temperature raising step of raising the temperature of the organometallic compound containing two or more kinds of metals to a predetermined temperature after extending in a film shape above the substance serving as the emitter part, It is desirable that the predetermined temperature increase rate be a temperature increase rate greater than 10 ° C. per minute.

  As described above, if the diameter of the through hole of the upper electrode can be appropriately reduced, the amount of electrons per unit area that can be emitted from one through hole can be increased, and the unit of the upper surface of the electron emission device can be increased. More through holes can be formed per area. Therefore, the amount of electron emission from the entire electron emission device can be further increased.

  On the other hand, according to experiments, if the shape of the upper surface of the emitter part (the surface of the emitter part on which the upper electrode is formed) is the same, the amount of electron emission increases as the flatness of the upper electrode improves under a predetermined driving condition. It has been found that can be increased. When the flatness of the upper electrode is improved, as shown in FIG. 50, the distance between the surface of the peripheral portion of the through-hole 204a (the edge of the through-hole) that faces the emitter portion 202 and the upper surface of the emitter portion 202 is increased. When the maximum value is set to d, the average value d1 of d with respect to each through-hole 204a becomes large. When the flatness of the upper electrode is lowered, as shown in FIG. 51, the average value d2 of the maximum value d in this case becomes smaller (d1> d2). When the electron emission amount was actually measured for these, it was confirmed that the electron emission device shown in FIG. 50 had a larger electron emission amount than the electron emission device shown in FIG.

  On the other hand, it was also confirmed that the flatness of the upper electrode 204 is improved when the firing temperature of the member constituting the upper electrode 204 is increased. It is presumed that this is because, due to the high firing temperature, metal grain growth occurs and the members constituting the upper electrode 204 contract. However, if the firing temperature is high, the through-holes become larger and the number of through-holes 204a decreases as the metal grains grow. As a result, the flatness of the upper electrode 204 is improved, while the diameter of the through hole 204a is increased and the number (density) of the through holes 204a is decreased, so that the amount of electron emission does not increase.

  Therefore, as a result of various experiments, the present inventor has improved the flatness of the upper electrode without increasing the firing temperature and promoting the grain growth of the metal by increasing the heating rate when firing the upper electrode. Found that you can. It has also been found that the number of through holes can be increased at the same time.

  Therefore, the inventor examined the temperature increase rate in an appropriate temperature increase step when firing an organometallic compound containing two or more kinds of metals, and said that it is desirable to increase the temperature increase rate above 10 ° C. per minute. Knowledge was obtained (see FIG. 32). As a result, an electron emission device having a large electron emission amount can be manufactured.

  Moreover, it can be said that such a temperature raising process is a process in which the decomposition process of the organometallic compound is included in the temperature raising process. If the pyrolysis process (decomposition process) of the organometallic compound is included in the temperature raising step, it is possible to improve both the flatness of the upper electrode and increase the number of through holes.

  In the above, the case where the upper electrode of an electron-emitting device is manufactured using an organometallic compound containing two or more kinds of metals has been described. On the other hand, when an upper electrode is manufactured using an organometallic compound containing one kind of metal, the organometallic compound is made to extend in the form of a film on the upper part of the substance that becomes the emitter portion, and then is heated to a predetermined temperature. It is preferable that the upper electrode is formed by a step including a temperature raising step of raising the temperature at a rate of temperature higher than 100 ° C. per minute until the organometallic compound is baked (see FIG. 32). ). This also makes it possible to manufacture an electron emission device with a large amount of electron emission.

  Also in this case, the temperature raising step is preferably a step in which a pyrolysis process of the organometallic compound is included in the temperature raising step. If the process of thermal decomposition of the organometallic compound is included in the temperature raising step, it is possible to simultaneously improve the flatness of the upper electrode and increase the number of through holes. At the same time, the diameter of the through hole can be reduced.

  Furthermore, the organometallic compound containing one kind of metal is preferably an organometallic compound of platinum.

  One of the objects of the electron emission device of the present invention is to provide an electron emission device having a large electron emission amount by forming an electron emission promoting layer on the upper surface of the emitter portion.

More specifically, the electron emission device of the present invention is:
An emitter portion made of a dielectric, a lower electrode formed at a lower portion of the emitter portion, and an upper electrode formed at an upper portion of the emitter portion so as to face the lower electrode with the emitter portion interposed therebetween. In the electron emission device that emits electrons from the emitter through the upper electrode by applying a driving voltage between the lower electrode and the upper electrode,
The upper electrode includes a plurality of through-holes that expose the emitter portion, and is formed such that a surface that is a peripheral portion of the through-hole and faces the emitter portion is separated from the emitter portion by a predetermined distance. As
The electrons emitted to the upper surface of the emitter section that is separated from the upper electrode by the predetermined distance and / or the upper surface of the emitter section and exposed to the outside through the through hole. An electron emission device including an electron emission promoting layer that increases the amount.

  In this case, the electron emission promoting layer is preferably made of a compound containing silicon. The electron emission promoting layer is preferably in the form of a fiber.

  Such an electron emission promoting layer may be any of an insulator, a semiconductor, and a conductor, and functions as follows to increase the amount of electron emission.

(When the electron emission promoting layer is made of an insulator)
When electrons are emitted by the polarization inversion of the emitter part, a part of the electrons on the surface of the emitter part moves along the upper part of the emitter part (the part where the surface resistance of the emitter part is generated), and the emitter part and the upper electrode Is recovered by the upper electrode at the part where the contact is made. If the electron emission promoting layer is an insulator, the resistivity in the direction along the upper surface in the vicinity of the upper surface of the emitter portion (herein also referred to as “surface resistivity”) is increased. The proportion of electrons collected by the electrode decreases. As a result, the amount of electron emission increases.

  Further, when the electron emission promoting layer is an insulator and has a fiber shape, the surface area of the upper surface of the emitter portion increases. As a result, the amount of electrons that can be accumulated increases and the amount of electron emission increases.

(When the electron emission promoting layer is made of semiconductor or conductor)
When the electron emission promoting layer of the semiconductor or conductor is not present, the affinity between the emitter and the electron accumulated in the emitter is higher than that in the semiconductor or conductor. Affinity between the electrons and the electrons is smaller. Thereby, when electrons are emitted by the polarization inversion of the emitter portion, the energy given to the electrons increases. As a result, the proportion of electrons collected by the upper electrode when attempting to pass through the through hole is reduced, and the amount of electron emission is increased.

  Further, when the electron emission promoting layer is a semiconductor or a conductor and has a fiber shape, the electric field concentrates on the electron emission promoting layer (particularly, the fiber tip). This increases the proportion of electrons emitted by polarization reversal among the electrons accumulated in the upper part of the emitter section. As a result, the amount of electron emission increases. In this case, if the electron emission promoting layer is made of a conductor having a low work function or a semiconductor having a low electron affinity, the amount of electron emission can be effectively increased.

  Embodiments of an electron emission device and a manufacturing method thereof according to the present invention will be described below with reference to the drawings. The electron emission device can be applied to various devices such as an electron irradiation device, a light source, and an electronic component manufacturing device, but is applied to a display in the following description.

(Construction)
As shown in FIGS. 1 to 3, the electron emission device 10 according to the embodiment of the present invention includes a substrate 11, a plurality of lower electrodes (lower electrode layers) 12, an emitter section 13, and a plurality of upper electrodes (upper electrode layers). ) 14, an insulating layer 15 and a plurality of focusing electrodes (focusing electrode layers) 16. 1 is a sectional view of the electron emission device 10 cut along a plane along line 1-1 of FIG. 3, which is a partial plan view of the electron emission device 10, and FIG. 2 is taken along line 2-2 of FIG. It is sectional drawing which cut | disconnected the electron emission apparatus 10 in the plane along.

  The substrate 11 has an upper surface and a lower surface parallel to a plane (XY plane) formed by the X axis and the Y axis orthogonal to each other, and the thickness direction is in the Z axis direction orthogonal to the X axis and the Y axis. It is the board which has. The substrate 11 is made of glass or a ceramic material. The ceramic material may be composed of, for example, a material mainly composed of zirconium oxide, a material mainly composed of aluminum oxide, or a material mainly composed of a mixture of aluminum oxide and zirconium oxide.

  Each of the lower electrodes 12 is made of a conductive material, which will be described later, and is formed in layers on the upper surface of the substrate 11. The shape of each lower electrode 12 in plan view is a strip shape having a longitudinal direction in the Y-axis direction. As shown in FIG. 1, the two lower electrodes 12 adjacent to each other are formed at positions separated by a predetermined distance in the X-axis direction. In FIG. 1, the lower electrodes 12 denoted by reference numerals 12-1, 12-2 and 12-3 are referred to as a first lower electrode, a second lower electrode and a third lower electrode, respectively, for convenience.

  The emitter section 13 is a dielectric having a high relative dielectric constant (for example, a three-component material PMN-PT-PZ of lead magnesium niobate (PMN), lead titanate (PT) and lead zirconate (PZ). It is formed on the upper surface of the substrate 11 and the upper surface of the lower electrode 12. The emitter section 13 is a thin plate body having an upper surface and a lower surface parallel to the XY plane and having a thickness direction in the Z-axis direction. On the upper surface of the emitter section 13, as shown in an enlarged view in FIG. 4, irregularities 13 a are formed by dielectric grain boundaries 13 a 1.

  Each of the upper electrodes 14 is made of a conductive material, which will be described later, and is formed in layers on the upper surface of the emitter section 13. The shape of each upper electrode 14 in plan view is a rectangle having a short side and a long side along the X-axis direction and the Y-axis direction, respectively, as shown in FIG. The plurality of upper electrodes 14 are separated from each other and arranged in a matrix.

  Each of the upper electrodes 14 faces each of the lower electrodes 12 and is disposed at a position overlapping with each of the lower electrodes 12 in plan view. In FIG. 1 and FIG. 3, the upper electrodes 14 denoted by reference numerals 14-1, 14-2 and 14-3 are respectively referred to as a first upper electrode, a second upper electrode and a third upper electrode for convenience. The plurality of upper electrodes 14 arranged in the X-axis direction are connected by a conductor (not shown) and are maintained at the same potential. For the purpose of stabilizing electron emission and protecting the electrode and the emitter, a resistor may be formed adjacent to each upper electrode and connected to a conductor through the resistor.

  As shown in FIG. 4 and FIG. 5 which is a partially enlarged plan view of the upper electrode 14, a plurality of fine through holes 14 a are formed in each of the upper electrodes 14. The shape of the through hole 14a in a front view is a substantially circular shape. The average diameter of the through holes 14a is 10 nm or more and less than 100 nm.

  Here, the average diameter of the through-holes is equal to the diameter of the through-hole if the shape of the through-hole is circular, and is the length of a plurality of different line segments passing through the center of the through-hole if the shape of the through-hole is not circular. It is defined as the average. The shape of the through hole does not have to be a circle, and may be a triangle, an ellipse, an oval, a thin groove (slit shape), or the like. In addition, when the shape of the through hole is a thin groove shape, the average diameter of the portion that can be regarded as a substantially independent through hole may be treated as the average diameter of the through hole, and when the groove width is substantially constant, What is necessary is just to treat the average of a groove width as an average diameter of the said through-hole. For example, when the center of gravity of the front shape of the through hole exists inside the through hole, the center of the through hole is defined as the center of gravity of the through hole.

  The shape of the through-hole formed in the upper electrode 14 is not limited to the substantially circular shape as in the above-described through-hole 14a, and as shown in FIGS. 6 to 10, the substantially elliptical shape 14b and the substantially elliptical shape (track shape) 14c. For example, the shape may be a shape mainly including a curved portion, a shape mainly including a straight portion such as a substantially triangle 14d and a substantially square 14e, and a narrow groove shape (slit) 14f. Moreover, a crescent moon shape, a boomerang shape, etc. may be sufficient.

  In the case of the narrow groove-shaped through hole 14f shown in FIG. 10, a constricted portion 14f1 exists. Therefore, the through-hole 14f can be regarded as a plurality of substantially rectangular through-holes 14f2. Therefore, the average diameter of the through holes 14f is defined as being equal to the average diameter of the individual rectangular through holes 14f2. When the narrow groove-shaped through hole does not have such a constricted portion, the width (slit width) of the through hole is regarded as the above-described average diameter. The matter applied to the groove-shaped through hole is similarly applied to the case where the shape of the through hole is a curved groove shape such as a crescent moon shape or a boomerang shape.

  The average diameter of such through-holes (through-holes 14a and the like) is desirably smaller than the particle diameter of the dielectric of the emitter section 13. A through-hole that does not include a grain boundary in the emitter portion immediately below the through-hole (see the broken-line circle A portion in FIG. 4) that includes the grain boundary 13a1 in the emitter portion (see the broken-line circle B portion in FIG. 4). .) Can emit more electrons. Therefore, if the average diameter of the through holes 14a of the upper electrode 14 is made smaller than the particle diameter of the dielectric that constitutes the emitter section 13, the number of through holes 14a that do not include the grain boundary of the emitter section 13 directly increases. Therefore, more electrons can be emitted. The diameter of the through hole 14a is 1/5 or less (more preferably 1/10 or less, more preferably) of the particle diameter of the dielectric to increase the number of through holes not including the grain boundary of the dielectric of the emitter section 13. Is 1/20 or less).

  Such through-holes 14a are preferably pores formed by metal metal crystal grains (a space formed by being surrounded by metal crystal grains that are bonded to each other when the metal crystal grains are formed).

  The pores (through holes 14a) formed by the metal crystal grains are coated on the upper surface of the substance to be the emitter portion by a thick film forming method such as screen printing, spray coating, and dipping coating, as will be described later.・ It is formed by a method of extending and firing by heating at a predetermined temperature, and its surface (metal crystal grain surface) is compared with the surface of the through-hole formed by later processing by laser processing etc. High crystallinity (high crystallinity on the metal surface). Therefore, it is estimated that electron emission is likely to be performed. Moreover, the through-hole which has a metal crystal grain surface can be obtained by sintering a metal. Therefore, an electron emission device having a through-hole having such a metal crystal grain surface has no damage to the emitter surface that occurs when the through-hole is processed by laser processing or the like. Further, if the upper electrode is provided with pores (through-holes) formed of metal crystal grains, there is an advantage that no fine shavings or the like of the electrode generated when the through-holes are formed by processing are generated.

  On the other hand, as shown in FIG. 11, the thickness t of the upper electrode 14 is 0.01 μm or more and 10 μm or less, preferably 0.05 μm or more and 1 μm or less. The maximum value d of the distance between the surface of the through hole 14a (14b to 14f) (the edge of the through hole) facing the emitter 13 and the emitter 13 (the upper surface of the emitter 13) is 0 μm. It is larger and is 10 μm or less, preferably 0.01 μm or more and 1 μm or less.

  By the way, the portion where the upper electrode 14 and the lower electrode 12 overlap in a plan view forms one element for electron emission. For example, in the apparatus shown in FIG. 1, the first lower electrode 12-1, the first upper electrode 14-1, and the emitter section 13 sandwiched between the first lower electrode 12-1 and the first upper electrode 14-1. Constitutes a first element. The emitter section 13 sandwiched between the second lower electrode 12-2, the second upper electrode 14-2, the second lower electrode 12-2, and the second upper electrode 14-2 constitutes a second element. ing. Furthermore, the emitter section 13 sandwiched between the third lower electrode 12-3, the third upper electrode 14-3, the third lower electrode 12-3, and the third upper electrode 14-3 constitutes a third element. ing. Thus, the electron emission device 10 includes a plurality of independent electron emission elements. In other words, the electron-emitting device can be said to be an electron-emitting device.

  Referring again to FIGS. 1 to 3, the insulating layer 15 is formed on the upper surface of the emitter section 13 so as to fill a space between the plurality of upper electrodes 14. The thickness of the insulating layer 15 (length in the Z-axis direction) is larger than the thickness (length in the Z-axis direction) of the upper electrode 14. As shown in FIGS. 1 and 2, the X-axis and Y-axis direction ends of each insulating layer 15 are disposed on the X-axis direction both ends and the Y-axis direction both ends of the upper electrode 14.

  The focusing electrode 16 is made of a conductive material (here, silver), and is formed in a layer shape on the insulating layer 15. As shown in FIG. 3, the shape of each focusing electrode 16 in plan view is a strip shape having a longitudinal direction in the Y-axis direction. Each focusing electrode 16 is located between the upper electrodes 14 adjacent to each other in the X-axis direction in plan view (between the upper electrodes of elements adjacent to each other in the X-axis direction, and obliquely above each upper electrode ( The upper direction means the positive direction of the Z-axis, and the same applies hereinafter)), that is, a position slightly spaced in the electron emission direction. All the focusing electrodes 16 are connected to each other by a layer made of a conductor (not shown) and are maintained at the same potential.

  In FIGS. 1 and 3, the focusing electrodes 16 denoted by reference numerals 16-1, 16-2, and 16-3 are respectively referred to as a first focusing electrode, a second focusing electrode, and a third focusing electrode for convenience. The Using this naming method, the second focusing electrode 16-2 is between the first upper electrode 14-1 of the first element and the second upper electrode 14-2 of the second element, and the first upper electrode 14-2 It can be said that it is formed obliquely above the electrode 14-1 and the second upper electrode 14-2. Similarly, the third focusing electrode 16-3 is between the second upper electrode 14-2 of the second element and the third upper electrode 14-3 of the third element, and the second upper electrode 14-2. And it can be said that it is formed obliquely above the third upper electrode 14-3.

  The electron emission device 10 further includes a transparent plate 17, a collector electrode (collector electrode layer) 18, and a phosphor 19.

  The transparent plate 17 is made of a transparent material (here, made of glass or acrylic), and is formed at a position above the upper electrode 14 (Z-axis positive direction) by a predetermined distance. The transparent plate 17 faces the substrate 11 and is disposed so that the upper and lower surfaces thereof are parallel to the upper surface of the emitter section 13 and the upper surface of the upper electrode 14 (in the XY plane).

  The collector electrode 18 is made of a conductive material (here, transparent conductive film, ITO), and is formed in a layer shape on the entire lower surface of the transparent plate 17. That is, the collector electrode 18 is disposed above the upper electrode 14 so as to face the upper electrode 14.

Each of the phosphors 19 is excited by electron irradiation and emits one of red, green, and blue light. Each phosphor 19 has substantially the same shape as each upper electrode 14 in a plan view, and is disposed at a position overlapping each upper electrode 14. In FIG. 1, the phosphors 19 denoted by reference numerals 19R, 19G, and 19B emit red, green, and blue, respectively. Accordingly, in this example, the red phosphor 19R is located immediately above the first upper electrode 14-1 (Z-axis positive direction), and the green phosphor 19G is located immediately above the second upper electrode 14-2. The blue phosphor 19B is located immediately above the third upper electrode 14-3. The space surrounded by the emitter section 13, the upper electrode 14, the insulating layer 15, the focusing electrode 16 and the transparent plate 17 (collector electrode 18) is preferably substantially vacuum (10 ² to 10 ⁻⁶ Pa, more preferably 10 ^{−. 3} to 10 ⁻⁵ Pa).

  In other words, the transparent plate 17 and the collector electrode 18 constitute a space forming member that forms a sealed space together with a side wall portion of the electron emission device 10 (not shown). The sealed space is maintained in a substantially vacuum. Therefore, the elements of the electron emission device 10 (at least the upper part of the emitter section 13 and the upper electrode 14 of each element) are arranged in a sealed space maintained in a substantially vacuum state by the space forming member.

  In addition, as shown in FIG. 1, the electron emission device 10 includes a driving voltage applying circuit (driving voltage applying means) 21, a focusing electrode potential applying circuit (focusing electrode potential difference applying means) 22, and a collector voltage applying circuit ( Collector voltage applying means) 23.

  The drive voltage application circuit 21 is connected to the signal control circuit 100 and the power supply circuit 110, and is driven between the upper electrode 14 and the lower electrode 12 (elements) facing each other based on a signal from the signal control circuit 100. A voltage Vin is applied.

  The focusing electrode potential applying circuit 22 is connected to the focusing electrode 16 and applies a predetermined negative potential (voltage) Vs to the focusing electrode 16. The collector voltage applying circuit 23 applies a predetermined positive voltage (collector voltage) Vc to the collector electrode 18.

(Principle and operation of electron emission)
Next, the operation principle regarding the electron emission of the electron emission device 10 configured as described above will be described by paying attention to one element.

  First, as shown in FIG. 12, the actual potential difference Vka (that is, the element voltage Vka) between the lower electrode 12 and the upper electrode 14 with respect to the potential of the lower electrode 12 is maintained at a positive predetermined voltage Vp, and the emitter section The description starts from a state immediately after all the electrons accumulated in the upper portion of 13 are emitted and no electrons are accumulated in the upper portion of the emitter section 13. At this time, the negative pole of the dipole of the emitter section 13 is in a state facing the upper surface of the emitter section 13 (Z-axis positive direction, that is, the upper electrode 14 side). This state is the state of the point p1 on the graph shown in FIG. The graph of FIG. 13 is a graph of voltage-polarization characteristics of the emitter section 13 in which the horizontal axis represents the element voltage Vka and the vertical axis represents the charge Q accumulated in the element.

  In this state, the drive voltage applying circuit 21 decreases the drive voltage Vin toward the first voltage Vm that is a negative predetermined voltage. As a result, the element voltage Vka decreases toward the point p3 via the point p2 in FIG. When the element voltage Vka becomes a voltage in the vicinity of the negative coercive electric field voltage Va shown in FIG. 13, the direction of the dipole of the emitter section 13 starts to reverse. That is, as shown in FIG. 14, polarization reversal (negative polarization reversal) starts.

  Due to this polarization inversion, the periphery of the upper electrode 14 forming the through hole 14a (tip portion), and the contact point between the upper surface of the upper electrode 14 and the emitter 13 and the surrounding medium (vacuum in this case). At (triple junction), the electric field increases (electric field concentration occurs), and electrons begin to be supplied from the upper electrode 14 toward the emitter section 13 as shown in FIG.

  The supplied electrons are accumulated mainly on the upper portion of the emitter portion 13 near the periphery of the through hole 14a of the upper electrode 14 (hereinafter also simply referred to as “near the portion immediately below the through hole 14a”). After that, when the predetermined time elapses and the negative side polarization reversal is completed, the element voltage Vka changes rapidly toward the negative predetermined voltage Vm. In this way, electrons are accumulated. This state is the state at point p4 in FIG.

  Next, the drive voltage application circuit 21 changes the drive voltage Vin to the second voltage Vp, which is a positive predetermined voltage. Thereby, the element voltage Vka starts to increase. At this time, until the element voltage Vka reaches a voltage Vb (point p6) smaller than the positive coercive field voltage Vd corresponding to the point p5 in FIG. 13, the charged state of the emitter section 13 is maintained as shown in FIG. Maintained. Thereafter, the element voltage Vka reaches a voltage in the vicinity of the positive coercive electric field voltage Vd. As a result, the electrons accumulated in the vicinity immediately below the through-hole 14 a are attracted to the upper electrode 14 by the potential applied to the upper electrode 14, and before and after this, the negative pole of the dipole faces toward the upper surface side of the emitter section 13. start. That is, as shown in FIG. 17, the polarization is reversed again (positive-side polarization reversal starts). This state is a state near the point p5 in FIG.

  In such a state, the electrons accumulated in the vicinity immediately below the through hole 14 a receive a coulomb repulsive force from a dipole whose negative electrode is inverted to the upper surface side of the emitter section 13, and a potential applied to the upper electrode 14. Is attracted to the upper electrode 14. As a result, as shown in FIG. 18, the electrons accumulated in the vicinity immediately below the through hole 14a are emitted upward (Z-axis positive direction) through the through hole 14a.

  When the positive-side polarization inversion is completed, the element voltage Vka starts to increase rapidly, and electrons are actively emitted. Next, the electron emission is completed, and the device voltage Vka reaches the second voltage Vp. As a result, the state of the emitter section 13 returns to the initial state shown in FIG. 12 (the state at the point p1 in FIG. 13). The above is a series of operating principles relating to accumulation (extinguishing) and emission (lighting / light emission) of electrons.

  When there are a plurality of elements, the drive voltage application circuit 21 needs to accumulate electrons by using the drive voltage Vin as the first voltage Vm only for the upper electrode 14 of the element that is to emit electrons, and to emit electrons. The drive voltage Vin is maintained at a value of “0” for the upper electrodes 14 that are not present, and then the drive voltage Vin is changed to the second voltage Vp simultaneously (simultaneously) for all the upper electrodes 14. It has become. As a result, electrons are emitted only from the upper electrode 14 (through hole 14a) of the element that has accumulated electrons on the upper portion of the emitter section 13. Therefore, polarization inversion does not occur in the emitter section 13 near the upper electrode 14 that does not need to emit electrons.

  By the way, when electrons are emitted through the through hole 14a of the upper electrode 14, as shown in FIG. 19, the electrons gradually spread (cone shape) and travel in the positive direction of the Z-axis. As a result, in the conventional apparatus, the electrons emitted from one upper electrode 14 (for example, the second upper electrode 14-2) are phosphors (for example, the green phosphor 19G) that exist immediately above the upper electrode 14. ) As well as adjacent phosphors (red phosphor 19R and blue phosphor 19B). When such a state occurs, the color purity decreases and the sharpness of the image decreases.

  On the other hand, the electron emission device 10 according to the present embodiment includes a focusing electrode 16 to which a negative potential is applied. The focusing electrode 16 is disposed between the adjacent upper electrodes 14 (between the upper electrodes of adjacent elements) and slightly above the upper electrode 14 (Z-axis positive direction). . Therefore, as shown in FIG. 20, the electrons emitted from the through hole 14 a of the upper electrode 14 are emitted in a substantially upward direction without spreading due to the electric field provided by the focusing electrode 16.

  As a result, the electrons emitted from the first upper electrode 14-1 reach only the red phosphor 19R, the electrons emitted from the second upper electrode 14-2 reach only the green phosphor 19G, and the third upper electrode Electrons emitted from the electrode 14-3 reach only the blue phosphor 19B. Therefore, a clearer image can be obtained without lowering the color purity of the display.

  A predetermined positive voltage Vc is applied to the collector electrode 18 by the collector voltage application circuit 23. As a result, the electrons emitted from the emitter section 13 travel above the upper electrode 14 while being accelerated (given high energy) by the electric field formed by the collector electrode 18. Therefore, since the phosphor 19 is irradiated with electrons having high energy, high luminance can be obtained.

<Examples of materials and manufacturing methods for each component>
Next, materials and manufacturing methods of the constituent members of the electron emission device will be described.

(Lower electrode 12)
A material having conductivity is used for the lower electrode 12. The lower electrode 12 can be formed by various film forming methods. For example, the lower electrode 12 is formed by an appropriate method among thick film forming methods such as screen printing, spray coating, and dipping coating, and thin film forming methods such as ion beam, sputtering, vacuum deposition, ion plating, CVD, and plating. It is formed. Hereinafter, materials suitable for the lower electrode 12 will be listed.

(1) Conductor having resistance to high-temperature oxidizing atmosphere (for example, simple metal or alloy)
Example) High melting point noble metals such as platinum, iridium, palladium, rhodium, molybdenum, etc.) Mainly composed of silver-palladium, silver-platinum, platinum-palladium, etc. alloys (2) Resistant to high-temperature oxidizing atmospheres Example of mixture of insulating ceramic and simple metal) Cermet material of platinum and ceramic material (3) Mixture of insulating ceramic and alloy having resistance to high-temperature oxidizing atmosphere (4) Carbon-based or graphite-based Material (5) Conductor film made of gold, silver, copper, aluminum, chromium, molybdenum, tungsten, nickel, etc., and formed using a thin film formation technique such as sputtering (6) Gold resinate printed film , Silver resinate print film and platinum resinate print film

  In addition, when adding a ceramic material in an electrode material, about 5-30 volume% is suitable for the ratio of the added ceramic material. Further, a material similar to the material of the upper electrode 14 described later may be used. The thickness of the lower electrode is preferably 20 μm or less, more preferably 5 μm or less.

(Emitter part 13)
As the dielectric constituting the emitter section 13, a dielectric having a relatively high relative dielectric constant (for example, a relative dielectric constant of 1000 or more) can be employed as described above. Hereinafter, materials suitable for the emitter section 13 are listed.

(1) Barium titanate, lead zirconate, lead magnesium niobate, lead nickel niobate, lead zinc niobate, lead manganese niobate, lead magnesium tantalate, lead nickel tantalate, lead antimony stannate, lead titanate, Magnesium lead tungstate, lead cobalt niobate, etc. (2) Ceramics containing any combination of substances described in (1) above

(3) The ceramic described in (2) above, further added with an oxide such as lanthanum, calcium, strontium, molybdenum, tungsten, barium, niobium, zinc, nickel, manganese, etc., described in (2) above Ceramics added with a combination of any of these oxides, or further appropriately added with other compounds (4) The main component has 50% or more of the substance described in (1) above material

  For example, for a binary nPMN-mPT of lead magnesium niobate (PMN) and lead titanate (PT) (where n and m are mole ratios), the PMN mole ratio is increased. As a result, the Curie point can be lowered and the relative dielectric constant at room temperature can be increased. In particular, nPMN-mPT in which n = 0.85 to 1.0 and m = 1.0-n has a relative dielectric constant of 3000 or more, and is thus very preferable as a material for the emitter portion. For example, nPMN-mPT with n = 0.91 and m = 0.09 has a relative dielectric constant of 15000 at room temperature, and nPMN-mPT with n = 0.95 and m = 0.05 has a relative dielectric constant of 20000 at room temperature. It becomes.

  Also, for example, for a ternary PMN-PT-PZ of lead magnesium niobate (PMN), lead titanate (PT) and lead zirconate (PZ), the relative dielectric constant can be increased by increasing the molar ratio of PMN. Can be increased. Furthermore, in this ternary system, the relative dielectric constant can be increased by using a composition near the morphotropic phase boundary (MPB) of tetragonal and pseudocubic or tetragonal and rhombohedral. it can.

  For example, when PMN: PT: PZ = 0.375: 0.375: 0.25, the relative dielectric constant is 5500, and when PMN: PT: PZ = 0.5: 0.375: 0.125, the relative dielectric constant is Thus, PMN-PT-PZ having such a composition is particularly preferable as a material for the emitter portion.

  Furthermore, it is preferable to improve the dielectric constant by mixing a metal such as platinum into these dielectrics within a range in which insulation can be ensured. In this case, for example, 20% by weight of platinum may be mixed in the dielectric.

  For the emitter portion, a piezoelectric / electrostrictive layer, an antiferroelectric layer, or the like can be further used. When a piezoelectric / electrostrictive layer is used for the emitter section, examples of the piezoelectric / electrostrictive layer include lead zirconate, lead magnesium niobate, lead nickel niobate, lead zinc niobate, lead manganese niobate, lead magnesium tantalate. And ceramics containing nickel tantalate, lead antimony stannate, lead titanate, barium titanate, lead magnesium tungstate, lead cobalt niobate and the like, or any combination thereof.

  As a matter of course, the emitter part may be one containing 50% by weight or more of the above compound as a main component. Among the ceramics, a ceramic containing lead zirconate is most frequently used as a constituent material of the piezoelectric / electrostrictive layer constituting the emitter portion.

Further, when the piezoelectric / electrostrictive layer is composed of ceramics, the ceramics may further include oxides such as lanthanum, calcium, strontium, molybdenum, tungsten, barium, niobium, zinc, nickel, manganese, or any of these. A combination of the above or other compounds as appropriate may be used. Further, a ceramic obtained by adding SiO ₂ , CeO ₂ , Pb ₅ Ge ₃ O ₁₁ or any combination thereof to the ceramic may be used. Specifically, PT-PZ-PMN system piezoelectric material SiO ₂ and 0.2 wt%, or a CeO ₂ 0.1 wt%, or Pb ₅ Ge ₃ O ₁₁ by the addition 1 to 2 wt% materials are preferred.

  More specifically, for example, it is preferable to use a ceramic containing, as a main component, a component composed of lead magnesium niobate, lead zirconate, and lead titanate, and further containing lanthanum or strontium.

  The piezoelectric / electrostrictive layer may be dense or porous. In the case of a porous material, the porosity is preferably 40% or less.

  When an antiferroelectric layer is used for the emitter section 13, the antiferroelectric layer is mainly composed of lead zirconate, a component composed mainly of lead zirconate and lead stannate, Furthermore, what added lanthanum oxide to lead zirconate, and what added lead niobate to the component which consists of lead zirconate and lead stannate are desirable.

  The antiferroelectric layer may be porous. In the case of a porous material, the porosity is desirably 30% or less.

Furthermore, strontium bismuthate tantalate (SrBi ₂ Ta ₂ O ₉ ) is suitable for the emitter part because it has low polarization reversal fatigue. Such a material with low polarization reversal fatigue is a layered ferroelectric compound and is represented by the general formula (BiO ₂ ) ²⁺ (A _m-1 B _m O _{3m + 1} ) ²⁻ . Here, the ions of metal A are Ca ²⁺ , Sr ²⁺ , Ba ²⁺ , Pb ²⁺ , Bi ³⁺ , La ^3+, etc., and the ions of metal B are Ti ⁴⁺ , Ta ⁵⁺ , Nb ^{5+ and the} like. Furthermore, it is possible to make semiconductors by adding additives to barium titanate, lead zirconate, and PZT piezoelectric ceramics. In this case, since an uneven electric field distribution is provided in the emitter section 13, the electric field can be concentrated near the interface with the upper electrode that contributes to electron emission.

  Also, the firing temperature of the emitter section 13 can be lowered by mixing the piezoelectric / electrostrictive / antiferroelectric ceramic with a glass component such as lead borosilicate glass or other low melting point compound (for example, bismuth oxide). Can do.

  In addition, when the emitter part is composed of piezoelectric / electrostrictive / antiferroelectric ceramics, the emitter part is a sheet-like molded body, a sheet-like laminate, or a laminate or bonded to another supporting substrate. Can be created from.

  Further, if the emitter part is formed of a material having a high melting point or a high evaporation temperature by using a lead-free material for the emitter part, an emitter part that is not easily damaged by the collision of electrons or ions can be obtained.

  The emitter is formed by various thick film forming methods such as screen printing method, dipping method, coating method, electrophoresis method, sedimentation method and aerosol deposition method, ion beam method, sputtering method, vacuum deposition method, ion plating method. It can be formed by various thin film forming methods such as a chemical vapor deposition method (CVD) and plating. In particular, it is possible to form a film at a low temperature of 700 ° C. or 600 ° C. or less by forming a powdered piezoelectric / electrostrictive material as an emitter portion and impregnating it with glass or sol particles having a low melting point. it can.

(Upper electrode 14)
In order to make the upper electrode 14 into a desired shape, for example, the following method can be used.
(1) Pattern forming method using screen printing method, photolithography method, etc. (2) Laser processing method using excimer laser, YAG laser, etc., and non-mechanical methods such as sizing and ultrasonic processing. Method to remove the necessary part and form a pattern

  In addition, in order to form the fine through hole described above in the upper electrode 14, for example, an optical lithography method, an electron beam and an X-ray lithography method, an excimer laser, a YAG laser, and a focused ion beam (FIB) are used. Further, as exemplified below, an organometallic compound is applied to the upper surface of the substance to be the emitter portion 13 by a thick film forming method such as screen printing, spray coating, and dipping coating. A method of firing by extending and heating at a predetermined temperature can be employed. This method of forming the upper electrode 14 by heating and firing does not require expensive manufacturing equipment and can form the upper electrode 14 in the atmosphere, which is advantageous for forming the upper electrode 14 having fine through holes. is there.

  Here, a method of forming the upper electrode 14 by the above-described heating / firing method will be specifically described.

(A: When using an organometallic compound containing two or more metals)
The upper electrode 14 is made of silver (Ag), gold (Au), iridium (Ir), rhodium (Rh), ruthenium (Ru), platinum (Pt), palladium (Pd), aluminum (Al), copper (Cu), “Organic metal compound containing two or more kinds of metals” among metals such as nickel (Ni), chromium (Cr), molybdenum (Mo), tungsten (W) and titanium (Ti) It is formed by firing at a predetermined temperature after extending in the form of a film on the top. When the “organic metal compound containing two or more kinds of metals” is fired at an appropriate temperature, the average diameter (10 nm or more and 100 nm or more) is extremely small compared to the case where the organometallic compound containing only one kind of metal is fired. It is possible to easily form the upper electrode 14 having a through hole having a lower The same effect can be obtained even when lithium (Li) is used as the metal. Furthermore, one or more kinds of metals and boron (B) may be included as such an organometallic compound.

  Here, “organometallic compound containing two or more kinds of metals” is a mixture of two or more kinds of organometallic compounds containing only one kind of metal, one kind of organometallic compound containing two or more kinds of metals, and Any one of a mixture of one organometallic compound containing two or more metals and another organometallic compound may be used. The “organometallic compound containing two or more metals” preferably contains at least a noble metal. Further, it is preferable to use platinum (Pt), gold (Au), or iridium (Ir) as the noble metal.

Furthermore, the material for forming the upper electrode 14 is a mixture of the above-mentioned “organometallic compound containing two or more metals” with an oxide electrode for suppressing polarization reversal fatigue or an oxide electrode for suppressing polarization reversal fatigue. Materials may be used. Examples of oxide electrodes that suppress polarization reversal fatigue include ruthenium oxide (RuO ₂ ), iridium oxide (IrO ₂ ), strontium ruthenate (SrRuO ₃ ), La _1-x Sr _x CoO ₃ (for example, x = 0. 3 or 0.5), La _1-x Ca _x MnO ₃ (eg, x = 0.2), La _1-x Ca _x Mn _1-y Co _y O ₃ (eg, x = 0.2, y = 0. 05).

  In order to form a plurality of through holes having an average diameter of 10 nm or more and less than 100 nm in the upper electrode 14, as described below, “an organometallic compound containing two or more kinds of metals” is present in a single phase state. It is good to consider whether to calcinate so as to exist in a mixed phase state.

(A-1) Example of production method in the case of firing in a single phase state (Production example 1)
Step 1: An organometallic compound containing only one kind of a predetermined metal as a base material (for example, Pt having a melting point of 1770 ° C.) and a metal having a higher melting point than the predetermined metal (Pt) (for example, a melting point of 2410 An organometallic compound containing only one kind of Ir) at ° C. is mixed and stirred at a metal weight ratio such that both metals exist in a single phase state near the firing temperature (here, around 700 ° C.). Here, Pt: Ir = 97: 3 by weight%. When the Pt organometallic compound and the Ir organometallic compound are mixed, in the presence of Pt: Ir = 90: 10 to 100: 0 by weight, that is, in the presence of Ir of 10% or less by weight, both metals are It may exist in a single-phase state around the firing temperature (here, around 700 ° C.).

Step 2: The paste-like organometallic compound (mixed organometallic compound) mixed in Step 1 is printed on the upper surface of the substance to be the emitter section 13 by screen printing to extend into a film shape, and then dried at 100 ° C. To do.
Step 3: Heat and raise the temperature up to 700 ° C. with an electric furnace at a rate of 47 ° C./min (47 ° C./min) and hold in that state for 30 minutes to fire (heat-treat) the organometallic compound.

  In step 2 and step 3, the organic metal compound containing two or more kinds of metals is extended in the form of a film over the substance serving as the emitter, and then heated to a predetermined temperature at a predetermined temperature increase rate. And a step of forming the upper electrode by firing the organometallic compound.

  In the electron emission device manufactured by this manufacturing method example 1, the organic metal compound containing only a predetermined metal (in this case, Pt) as a base material is heated to 700 ° C. at 47 ° C./min and at 700 ° C. The amount of electron emission increased compared to the fired one. The reason for this is shown in FIG. 21, which is an enlarged photograph of the actual upper electrode surface, because the presence of a metal having a high melting point (in this case, Ir) suppresses the grain growth of Pt in a single phase with Ir. As described above, it is considered that the upper electrode having a through hole having a minute average diameter of 10 nm or more and less than 100 nm (50 nm or less in the example of Pt and Ir) can be easily formed.

  FIG. 22 shows an actual enlargement of the surface of the upper electrode formed by a conventional method in which only an organometallic compound containing only one type of Pt is fired under the above conditions (firing rate 700 ° C., temperature rising rate 47 ° C./min). It is a photograph. As understood from FIG. 22, the average diameter of the through holes of the upper electrode according to the conventional manufacturing method is 100 to 5000 nm, which is relatively large. Therefore, according to the manufacturing method example 1 described above, it is understood that a through hole having a very small average diameter is easily formed as compared with the conventional method.

  21 to 24, FIG. 28, FIG. 33 and FIG. 34 are enlarged photographs obtained by photographing the surface of the upper electrode formed by each manufacturing method at the same magnification. FIG. 29 is an enlarged photograph of the surface of the upper electrode shown in FIG. 28 taken at a higher magnification than in FIG.

(A-2) Manufacturing method example in the case of firing in a mixed phase state (Manufacturing method example 2)
Step 1: An organometallic compound containing only one kind of a predetermined metal (for example, Pt having a melting point of 1770 ° C.) as a base material, and another metal having a lower melting point than the predetermined metal (Pt) (for example, a melting point) Is mixed and stirred at a metal weight ratio such that both metals are present in a mixed phase near the firing temperature (here, around 650 ° C.). Here, the weight percentage is Pt: Au = 95: 5. When the Pt organometallic compound and the Au organometallic compound are mixed, Pt: Au = 22: 78 to 97: 3 by weight%, that is, if both metals are included by 3% or more and 78% or less by weight%. May exist in a mixed phase around the firing temperature (here, around 650 ° C.).

Step 2: The paste-like organometallic compound (mixed organometallic compound) mixed in Step 1 is printed on the upper surface of the substance to be the emitter section 13 by screen printing to extend into a film shape, and then dried at 100 ° C. To do.
Step 3: Heat and heat up to 650 ° C. with an electric furnace at a rate of temperature rise of 43 ° C./min (43 ° C./min) and hold in that state for 30 minutes to fire (heat treat) the organometallic compound.

  In step 2 and step 3, the organic metal compound containing two or more kinds of metals is extended in the form of a film over the substance serving as the emitter, and then heated to a predetermined temperature at a predetermined temperature increase rate. And a step of forming the upper electrode by firing the organometallic compound.

  In the electron emission device manufactured by this manufacturing method example 2, the organometallic compound containing only a predetermined metal (in this case, Pt) as a base material is heated to 700 ° C. at 47 ° C./min and at 700 ° C. The amount of electron emission increased compared to the fired one. As described above, when an organometallic compound containing two or more kinds of metals is fired so that each metal exists in a mixed phase state, Pt and Au form two or more different phases to form each phase. Inhibits metal grain growth. As a result, it is possible to form an upper electrode having through holes having a minute average diameter of 10 nm or more and less than 100 nm.

  FIG. 23 is an enlarged photograph of the surface of the upper electrode manufactured based on the manufacturing method example 2 described above. As is apparent from a comparison between FIG. 23 and FIG. 22, which is an enlarged photograph of the upper electrode surface according to the conventional manufacturing method, according to the manufacturing method 2 described above, a through hole having a very small average diameter can be easily formed. It is understood that it is formed.

  An organometallic compound containing only one kind of metal can be obtained by previously synthesizing one kind of organometallic compound containing two kinds of metals and firing the organometallic compound in the same manner as described above. It is possible to form an upper electrode having through-holes with a smaller average diameter than when a single body is fired. As an example of the organometallic compound by such synthesis, a Pt—Au organometallic compound that is a material capable of forming a through hole having a minute diameter only by containing about 5 wt% of Au can be given.

(A-3) First production method example when using three types of organometallic compounds (Production method example 3)
Step 1: An organometallic compound containing only one kind of a predetermined metal (for example, Pt having a melting point of 1770 ° C.) as a base material, and another metal having a lower melting point than the predetermined metal (Pt) (for example, a melting point) And an organometallic compound containing only one type of metal having a melting point higher than the predetermined metal (Pt) (for example, Ir having a melting point of 2410 ° C.) Are mixed and stirred at a predetermined metal weight ratio. Here, the weight percentage is Pt: Au: Ir = 93: 4.5: 2.5. In this way, near the firing temperature (here, around 700 ° C.), Pt and Ir are in a single-phase state, and the single-phase component exists in a mixed phase with Au.

Step 2: The paste-like organometallic compound (mixed organometallic compound) mixed in Step 1 is printed on the upper surface of the substance to be the emitter section 13 by screen printing to extend into a film shape, and then dried at 100 ° C. To do.
Step 3: Heat and raise the temperature up to 700 ° C. with an electric furnace at a rate of 47 ° C./min (47 ° C./min) and hold in that state for 30 minutes to fire (heat-treat) the organometallic compound.

  In step 2 and step 3, the organometallic compound containing two or more kinds of metals is extended in the form of a film over the substance serving as the emitter portion, and then heated to a predetermined temperature at a predetermined temperature increase rate. And a step of forming the upper electrode by firing the organometallic compound.

  As shown in FIG. 24 which is an actual enlarged photograph, the electron-emitting device manufactured by this manufacturing method example 3 has a fine average diameter of 10 nm or more and less than 100 nm (50 nm or less in the example of Pt and Ir). An upper electrode having a large number of holes is provided. Therefore, in the electron emission device manufactured by this manufacturing method example 3, the temperature of the organometallic compound containing only a predetermined metal (in this case, Pt) as a base material is increased to 700 ° C. at 47 ° C./min and 700 ° C. The amount of electron emission increased compared to that fired at (see FIG. 22).

  Furthermore, the amount of electron emission from the electron-emitting device manufactured by the manufacturing method example 3 was larger than that of either the manufacturing method example 1 or the manufacturing method example 2.

  The electron emission device manufactured as described above includes a through-hole having an average diameter of 10 nm or more and less than 100 nm in the upper electrode 14. Thereby, as shown in FIG. 25, the amount of electrons emitted from one through hole becomes very large. Therefore, the electron emission device can emit more electrons with less power consumption.

  Such a phenomenon is considered to be due to the following reason. First, as can be understood from the equipotential lines shown in FIG. 49, when the average diameter of the through holes 204a is 100 nm or more, electrons are easily supplied from the periphery of the through holes 204a, but the electric field strength is low. This is presumably due to the fact that it is difficult for the small through hole 204a to accumulate in the vicinity of the central portion. As a result, it is considered that electrons are accumulated immediately below the peripheral portion of the through-hole 204a (region indicated by reference numeral A in FIG. 49).

  On the other hand, in the electron emission device according to the embodiment of the present invention described above, since the diameter of the through hole 14a of the upper electrode 14 is less than 100 nm, as understood from the equipotential lines shown in FIG. It is difficult for the equipotential lines to bulge from the through hole 14a. Therefore, as indicated by reference numeral B in FIG. 26, the electric field strength is stronger and more uniform in a wider region of the upper surface of the emitter portion 13 existing immediately below the through hole 14a, so that electrons are accumulated over a wider region. can do. As a result, the amount of electrons per unit area that can be emitted from one through hole 14a can be increased.

Further, as described above, since electrons are mainly accumulated directly below the periphery of the through hole, the larger the total length (periphery distance) of the periphery of the through hole, the more electrons are emitted. . For example, as shown in (A) of FIG. 27, when the diameter of the through hole (diameter) of 10r, the length of the peripheral portion of the fixed area L ² per through hole is 10Paiaru. In contrast, when the diameter of the through hole is assumed to be r, for example, as shown in (B) of FIG. 27, it is possible to form a 64 holes per fixed area L ^2, around the The total length of the parts is 64πr.

  As is clear from this, in the electron emission device 10 according to the embodiment of the present invention, the diameter of the through hole 14a of the upper electrode 14 is as small as 10 nm or more and less than 100 nm. More through holes can be formed per unit area of the upper surface. Therefore, more electrons can be accumulated and emitted from the unit area.

On the other hand, in the electron emission device 10 according to the embodiment of the present invention, the average diameter of the through holes 14a of the upper electrode 14 is 10 nm or more. If the average diameter of the through holes is smaller than 10 nm, the amount of electrons emitted may be reduced due to the following estimation reason.
The region for accumulating electrons on the upper surface of the emitter section 13 becomes too small, and the amount of accumulated electrons decreases.
When electrons are emitted, the number of electrons that collide with the upper electrode increases, and the proportion of electrons captured by the upper electrode increases.

  From the above, the electron emission device 10 provided with through holes having an average diameter of 10 nm or more and less than 100 nm in the upper electrode can emit electrons with high efficiency. Moreover, in the electron emission apparatus 10, since the through-hole 14a is very small, the emitted electron does not spread. That is, the electron emission device 10 can accurately emit electrons in a direction perpendicular to the plane formed by the emitter section 13 and the upper electrode 14.

  Furthermore, another method for manufacturing the upper electrode having such fine through holes will be described.

(A-4) Second production method example when using three kinds of organometallic compounds (Production Example 4)
Step 1: In the same manner as in Production Example 3 in the case of firing in a single-phase and mixed-phase state, an organometallic compound containing only one kind of a predetermined metal as a base material (for example, Pt having a melting point of 1770 ° C.), An organometallic compound containing only one kind of other metal having a lower melting point than the predetermined metal (Pt) (for example, Au having a melting point of 1064 ° C.) and a metal having a higher melting point than the predetermined metal (Pt) ( For example, an organometallic compound containing only one kind of Ir) having a melting point of 2410 ° C. is mixed and stirred at a predetermined metal weight ratio. Here, the weight percentage is Pt: Au: Ir = 93: 4.5: 2.5. In this way, near the firing temperature (here, around 700 ° C.), Pt and Ir are in a single-phase state, and the single-phase component exists in a mixed phase with Au.

  Step 2: The paste-like organometallic compound (mixed organometallic compound) mixed in Step 1 is printed on the upper surface of the substance to be the emitter section 13 by screen printing to extend into a film shape, and then dried at 100 ° C. To do.

  Step 3: In an infrared heating furnace, the temperature is increased to 700 ° C. at a rate of temperature increase of 23 ° C./second (23 ° C. per second, ie, 1400 ° C./minute), and the temperature is maintained for 30 minutes. Is fired (heat treatment).

  In Step 2 and Step 3, the organometallic compound containing two or more kinds of metals is formed in a film shape on the upper part of the substance serving as the emitter portion, and then a predetermined temperature increase rate (1400 ° C. / And a step of forming the upper electrode by firing the organometallic compound. In addition, as for this predetermined temperature increase rate, it is desirable to set it as a temperature increase rate larger than 10 degree-C per minute so that it may mention later.

  The electron-emitting device manufactured by this manufacturing method example 4 is more electron-emitting than the electron-emitting device manufactured by the above-mentioned "1st manufacturing method example (manufacturing method example 3) in the case of baking in the state of a single phase and a mixed phase". Became very large. The reason for this is that the electron-emitting device manufactured by the manufacturing method example 4 has a diameter of 10 to 100 nm as shown in FIG. 28 which is an actual enlarged photograph and FIG. 29 which is an enlarged photograph at a magnification higher than that of FIG. This is probably because the fine through-holes are formed in a large amount, the flatness of the upper electrode is improved, and the distance d shown in FIG. 50 is increased. The reason why a large number of fine through-holes are formed is that the rate of temperature rise is large, so that the pyrolysis of the organometallic compound occurs rapidly, and at that time, all the organometallics change into metal particles almost simultaneously. This is presumably because the diameter of the metal particles is small and uniform.

  30 and 31 are graphs showing the electron emission characteristics of the electron-emitting device manufactured by the manufacturing method example 4 described above. 30 shows the electron emission amount with respect to the negative predetermined voltage Vm (first voltage) described with reference to FIG. 13 when the positive predetermined voltage Vp (second voltage) described with reference to FIG. 13 is constant. Is a graph in which is plotted. In FIG. 30, the negative predetermined voltage Vm is represented by an electric field obtained by dividing the negative predetermined voltage Vm by the thickness (film thickness) of the emitter section 13. On the other hand, FIG. 31 is a graph plotting the amount of electron emission with respect to the positive predetermined voltage Vp (second voltage) when the negative predetermined voltage Vm (first voltage) is constant. In FIG. 31, the positive predetermined voltage Vp is represented by an electric field obtained by dividing the positive predetermined voltage Vp by the thickness (film thickness) of the emitter section 13.

  FIG. 32 is a graph showing, as a triangular plot, the results of measuring the electron emission amount of an electron emission device having an upper electrode manufactured by changing the temperature rising rate in Step 3 of Manufacturing Method Example 4. As is apparent from FIG. 32, the electron emission amount is increased by setting the temperature rising rate to be greater than 10 ° C./min. This tendency is not limited to the case where the upper electrode is produced using a mixture of organometallic compounds containing three kinds of metals (for example, Pt, Au and Ir) as in Production Example 4, but the above Production Example 1 or Production Method is used. As in Example 2, it was confirmed that this was also true when the upper electrode was produced using “an organometallic compound containing two kinds of metals”.

  Actually, Pt and Ir were mixed and stirred as Pt: Ir = 97: 3 by weight%, printed on the material to be the emitter section 13 in the same manner as the above manufacturing method, dried at 100 ° C. FIG. 33 shows an enlarged photograph of the surface of the upper electrode manufactured (fired) by raising the temperature to 700 ° C. at a temperature rate of 1400 ° C./min and holding in that state for 30 minutes. Also from FIG. 33, if “an organometallic compound containing two or more kinds of metals” is used and the rate of temperature rise is increased, a large number of extremely fine through-holes are formed as compared with the case where the rate of temperature rise is small. I understand that.

(B: When using only an organometallic compound containing one kind of metal)
The upper electrode 14 is made of silver (Ag), gold (Au), iridium (Ir), rhodium (Rh), ruthenium (Ru), platinum (Pt), palladium (Pd), aluminum (Al), copper (Cu), It can be formed by firing only an organometallic compound containing only one kind of metal such as nickel (Ni), chromium (Cr), molybdenum (Mo), tungsten (W), and titanium (Ti). For metals other than noble metals, it is desirable to reduce and fire.

  However, in this case, if heating and firing is performed with a normal electric furnace at a relatively low temperature increase rate, a through hole having a fine diameter cannot be formed as shown in FIG. If the temperature at the time of firing is lowered (for example, 600 ° C.) to suppress Pt grain growth, the average diameter of the through holes can be reduced, but the flatness of the upper electrode deteriorates, as shown in FIG. Therefore, the amount of electron emission is reduced. Therefore, in the present invention, an infrared heating furnace is used for heating and firing at a very high temperature increase rate. As a result, the upper electrode 14 having through holes having good flatness and having many extremely small average diameters (10 nm or more and less than 100 nm) can be easily formed. Hereinafter, specific examples of the production method will be described.

(B-1: Example of production method using organometallic compound containing one kind of metal (Production example 5)
Step 1: A paste-like organometallic compound containing only one kind of a predetermined metal (here, Pt) is printed on the upper surface of the substance to be the emitter section 13 by screen printing to extend into a film shape, and then 100 ° C. Dry with.
Step 2: Heat and heat up to 600 ° C. with an infrared heating furnace at a rate of temperature increase of 20 ° C./second (20 ° C./second, ie, 1200 ° C./minute), and hold in that state for 30 minutes to hold the organometallic compound Is fired (heat treatment).

  In Step 1 and Step 2, an organic metal compound containing one kind of metal is formed in a film shape on the upper part of the substance serving as the emitter portion, and then a predetermined temperature increase rate (in this case, 1200). And a step of forming the upper electrode by firing the organometallic compound. In addition, as for this predetermined temperature increase rate, it is desirable to set it as the temperature increase rate larger than 100 degree-C per minute so that it may mention later.

  FIG. 34 is an enlarged photograph of the surface of the upper electrode manufactured based on the manufacturing method example 5 described above. As is clear from comparison between FIG. 34 and FIG. 22, when an organometallic compound containing only one kind of Pt is used, if the rate of temperature rise is 20 ° C./second and the rate of temperature rise is much higher than 47 ° C./min. It is understood that through holes having a very small average diameter are easily formed in the upper electrode.

  As described above, according to Production Example 5, a large amount of fine through holes having a diameter of 10 to 100 nm were formed, and the flatness of the upper electrode was improved, and the distance d shown in FIG. 50 was increased. Thus, an electron emission device with a large amount of electron emission can be manufactured. The reason why a large number of fine through-holes are formed is that, as described above, when the pyrolysis of the organometallic compound occurs rapidly due to the high temperature rise rate, all the organometallics are changed into metal particles almost simultaneously. As a result, the diameter of the metal particles is estimated to be small and uniform.

  Further, in FIG. 32, the result of measuring the electron emission amount of the electron emission device having the upper electrode manufactured by changing the temperature rising rate in Step 2 of Production Method 5 is shown by a square plot. As is clear from FIG. 32, when an organometallic compound containing only one kind of metal (here, Pt) is used, the electron emission amount is increased by setting the temperature rising rate to be greater than 100 ° C./min. Yes. Therefore, when the upper electrode is formed using an organometallic compound containing only one kind of metal, the rate of temperature rise should be greater than 100 ° C./min.

<About thermal decomposition of organometallic compounds>
By the way, when the organometallic compound is heated when the upper electrode is formed (heat treatment, firing), the organometallic compound is thermally decomposed. In this pyrolysis, the organic component is burned out, and finally only the metal component remains. Heat is generated when this organic component is burned out. FIG. 35 is a graph showing the results of measuring the relationship between the amount of heat generated and the temperature of the organometallic compound.

  As is clear from FIG. 35, the amount of heat generated has a certain width and peak. The temperature at this peak is defined as the decomposition temperature. Depending on the type of the organometallic compound, peaks appear at two or more locations (that is, the decomposition temperature is two or more). The decomposition process (thermal decomposition process) is a process in which heat is generated in a temperature range from the start temperature temp1 to the end temperature temp2 of this peak.

  The temperature raising steps of Production Method Example 4 and Production Method Example 5 include at least the decomposition process. In other words, the temperature of the organometallic compound passes through the temperature range of the decomposition process during the temperature raising step. In addition, when a peak appears in two or more places, the temperature of the organometallic compound has a temperature range from the maximum peak start temperature temp1 to the end temperature temp2 during the temperature raising process of the above production method 4 and the above production method example 5. Shall pass. In addition, although it is a very small value, a peak may appear for reasons other than thermal decomposition of an organometallic compound.

<About the structure of the upper electrode>
Here, the upper electrode shown in FIG. 24 (Pt: Au: Ir = 93: 4.5: 2.5, temperature rising rate 47 ° C./min, upper electrode baked by holding at 700 ° C. for 30 minutes) was provided. The electron emission device and the electron emission device provided with the upper electrode shown in FIG. 33 (Pt: Ir = 97: 3, temperature rising rate 1400 ° C./minute, upper electrode fired by holding at 700 ° C. for 30 minutes) The change of the amount of electron emission with respect to the number of electron emission was investigated. FIG. 36 is a graph showing the results. In FIG. 36, the electron emission amount is shown by a relative value. Further, the triangular plot shows the characteristics of the electron-emitting device having the upper electrode shown in FIG. 24, and the square plot shows the characteristics of the electron-emitting device having the upper electrode shown in FIG.

  In this comparison, the upper electrode shown in FIG. 24 is employed as a representative of the upper electrode fired with a relatively low temperature increase rate during firing as an upper electrode using an organometallic compound containing two or more kinds of metals. Electrode. Hereinafter, such an upper electrode is referred to as a “low temperature increase rate firing upper electrode”. The upper electrode shown in FIG. 21, FIG. 22, and FIG. On the other hand, the upper electrode shown in FIG. 33 is an electrode used as a representative of the upper electrode fired at an extremely high temperature increase rate during firing as an upper electrode using an organometallic compound containing two or more kinds of metals. It is. Hereinafter, such an upper electrode is referred to as a “high heating rate firing upper electrode”. For example, the upper electrode shown in FIG. 34, which is an upper electrode using an organometallic compound containing one kind of metal, is included in the upper electrode shown in FIGS. 28 and 33 in addition to the upper electrode shown in FIGS. .

  As is clear from FIG. 36, when electrons are repeatedly emitted, the electron emission device provided with the upper electrode shown in FIG. 33 (that is, the high heating rate firing upper electrode) is more suitable for the upper electrode shown in FIG. That is, the electron emission amount did not decrease and the durability was superior to that of the electron emission device provided with the low temperature increase rate firing upper electrode). This is considered to be due to the following reason.

  As shown in FIG. 37, which is a partial cross-sectional view, the low heating rate firing upper electrode 14LS is formed by combining relatively large metal particles. For this reason, in one lump portion formed by bonding particles, pores communicating the space between the emitter section 13 and the upper electrode 14LS and the upper space (sealed space) SP above the upper electrode 14LS. Is difficult to form.

As a result, even when the pressure of the upper space SP is reduced so that the upper space SP approaches a vacuum when manufacturing the electron emission device, gas molecules (for example, between the emitter portion 13 and the upper electrode 14LS) (for example, , H ₂ O, N ₂ , O ₂ , CO ₂ , hydrocarbon, etc.) gas moves on the lower surface of the upper electrode 14LS and the upper surface of the emitter section 13, but hardly reaches the upper space SP. Therefore, the gas molecule gas remains in the space between the emitter section 13 and the upper electrode 14LS. Such gas molecules gas are ionized and gradually adsorbed to the upper electrode 14LS when the electron emission operation (accumulation and emission of electrons) is performed. The adsorbed ions inhibit the supply of electrons from the upper electrode 14LS to the emitter section 13, and also inhibit the emission of electrons through the through holes of the upper electrode 14LS. As a result, it is considered that the electron emission device provided with the low temperature rising rate firing upper electrode has a reduced electron emission amount from a relatively early stage.

  On the other hand, as shown in FIG. 38 which is a partial sectional view of the high heating rate firing upper electrode 14HS, metal particles having a smaller particle diameter than the metal particles forming the low heating rate firing upper electrode 14LS are combined. It is formed by doing. For this reason, even in one lump portion formed by bonding particles, a large number of pores communicating the space between the emitter portion 13 and the upper electrode 14HS and the upper space SP of the upper electrode 14HS are formed. .

  That is, it can be said that the upper electrode 14HS is an electrode having a three-dimensional network structure formed by bonding particles (for example, spherical metal particles each). In other words, it can be said that the upper electrode 14HS is a porous body formed by chemically bonding two or more particles in the thickness direction. Furthermore, the upper electrode 14HS is a bulky (bulky) electrode formed by integrally bonding metal particles, and has a thickness direction (a direction perpendicular to a plane formed by the upper electrode, that is, a Z-axis direction). It can also be said that the electrode has pores penetrating therethrough (open pores different from through-holes for electron emission).

  Therefore, when manufacturing the electron-emitting device, if the pressure in the upper space SP is lowered so that the upper space SP approaches a vacuum, gas molecules gas between the emitter portion 13 and the upper electrode 14HS are formed in the upper electrode 14HS. It is easy to move to the upper space SP through the pores. As a result, the number of gas molecules gas remaining in the space between the emitter section 13 and the upper electrode 14HS is reduced. For this reason, even if the number of times of electron emission increases, such gas molecules gas do not hinder the supply of electrons from the upper electrode 14HS to the emitter section 13, and the electrons passing through the through holes of the upper electrode 14HS do not interfere. It does not inhibit release. The above is considered to be the reason why when the electron emission device is provided with the high temperature rising rate firing upper electrode, the electron emission amount is not easily lowered even when the electron emission is repeated.

<About the average open area ratio of the upper electrode>
The average open area ratio (porosity) of various upper electrodes (upper electrodes having a large electron emission amount) included in the electron emission device according to the present invention described above was measured. The average open area ratio refers to the pores communicating the upper surface and the lower surface of the upper electrode 14 with respect to the area of the upper electrode 14 (not only the through holes 14a that directly expose the emitter portion 13 to the upper space, but also the upper surface of the emitter portion 13). (Including a hole communicating with the upper surface of the upper electrode 14)).

  As a result of measurement, the average aperture ratio of the upper electrode was 5% or more and 60% or less. In this case, the average aperture ratio is more preferably 10% or more and 60% or less, and further preferably 20% or more and 60% or less. This is because when the average hole area ratio is less than 5%, the area of the through-hole 14a that emits electrons decreases excessively, and the amount of electron emission decreases to an extent insufficient for an electron-emitting device. In addition, if the average hole area ratio is larger than 60%, it becomes difficult to cause polarization inversion in the emitter section 13 because there are few conductive portions as electrodes, and as a result, the amount of electron emission becomes as an electron emission device. Is reduced to an insufficient level, and the strength of the upper electrode 14 is reduced (the upper electrode becomes weak).

<Infrared heating furnace>
Next, an infrared heating furnace used in the method for manufacturing the upper electrode will be briefly described. Usually, an electric furnace is used when manufacturing an upper electrode by baking an organometallic compound. In the electric furnace, air is heated by a heater, and the sample is heated by the heat of the air. Therefore, the rate of temperature rise by the electric furnace is about 50 ° C./min at the maximum.

  On the other hand, the infrared heating furnace 40 is, for example, as shown in FIG. 39A, which is a front view, and in FIG. 39B, in which the infrared heating furnace 40 is cut along a plane along line 3-3. Further, a main body 41 having a heat reflecting plate on the inner surface, infrared lamps 42 arranged at four corners, and a hollow cylindrical quartz tube 43 arranged at the center are provided. The sample S to be heated is fixed on the table 44 and is arranged in the central portion of the main body 41 together with the table 44.

  The infrared heating furnace 40 directly heats the sample S by radiant heat from the infrared lamp 42. Therefore, the rate of temperature increase by the infrared heating furnace 40 is a maximum of about 6000 ° C./min. Note that the infrared heating furnace 40 has a feature that it is difficult to increase the temperature that easily transmits infrared rays. For this reason, the infrared heating furnace 40 has an advantage that when the glass or the like is used for the substrate of the electron emission device, the electrode or the like can be fired while suppressing an increase in the substrate temperature. Thus, since the infrared heating furnace 40 can heat the sample S at a very high temperature increase rate, it is suitable for the manufacturing method of the upper electrode as in Production Method Example 4 and Production Method Example 5.

  In addition, as a method of heating the sample S at a high temperature increase rate, in addition to infrared heating, an electromagnetic wave irradiation process using microwaves or millimeter waves, a plasma process using discharge plasma or thermal plasma, a laser irradiation process, and an induction heating process Etc. These can also be applied to Production Method Example 4 and Production Method Example 5.

  Next, an electron emission device 50 according to another embodiment of the present invention will be described with reference to FIG. The electron emission device 50 has the same configuration as the electron emission device 10. Furthermore, the electron emission device 50 is exposed to the outside through the through hole 14a on the upper surface of the emitter portion 13 and a portion separated from the upper electrode 14 by a predetermined distance and / or the upper surface of the emitter portion 13. The portion is provided with an electron emission promoting layer 51 that increases the amount of electrons emitted.

  The electron emission promoting layer 51 is made of a compound containing silicon (Si), for example, and is a fiber-like (thread-like) layer. The electron emission promoting layer 51 may be any of an insulator, a semiconductor, and a conductor, and has the following advantages.

(Advantages when the electron emission promoting layer is made of an insulator)
When electrons are emitted by the polarization reversal of the emitter section 13, a part of the electrons on the surface of the emitter section 13 moves along the upper portion of the emitter section 13 (the portion where the surface resistance of the emitter section 13 is generated). The portion 13 and the upper electrode 14 are collected by the upper electrode 14 at the portion where they are in contact. If the electron emission promoting layer 51 is an insulator, the resistivity (surface resistivity) in the direction along the upper surface in the vicinity of the upper surface of the emitter section 13 is increased. The ratio of decreases. As a result, the amount of electron emission increases.

  Further, when the electron emission promoting layer 51 is an insulator and has a fiber shape, the surface area of the upper surface of the emitter section 13 increases. As a result, the amount of electrons that can be accumulated increases and the amount of electron emission increases.

(Advantages when the electron emission promoting layer is made of a semiconductor or conductor)
When the semiconductor or conductor electron emission promoting layer 51 is not present, the affinity between the emitter 13 and the electrons accumulated in the emitter 13 is higher than that of the semiconductor or conductor electron emitting promoting layer 51 and the emitter. The affinity with the electrons stored in the part 13 is smaller. Thereby, when electrons are emitted by the polarization inversion of the emitter section 13, the energy given to the electrons increases. As a result, the proportion of electrons collected by the upper electrode 14 when attempting to pass through the through hole 14a decreases, and the amount of electron emission increases.

  Further, when the electron emission promoting layer 51 is a semiconductor or a conductor and has a fiber shape, an electric field concentrates on the electron emission promoting layer (particularly, the fiber tip). Thereby, the ratio of the electrons emitted by polarization inversion among the electrons accumulated in the upper part of the emitter section 13 increases. As a result, the amount of electron emission increases. In this case, if the electron emission promoting layer 51 is made of a conductor having a small work function or a semiconductor having a small electron affinity, the amount of electron emission can be effectively increased.

  It is advantageous to form the electron emission promoting layer 51 on the surface of the upper electrode 14 in order to increase the amount of electron emission. In this case, if the electron emission promoting layer 51 is an insulator, an attack on the upper electrode 14 by the ionic substance remaining in the sealed space can be suppressed. As a result, the durability of the upper electrode 51 can be improved.

  Further, when the electron emission promoting layer 51 is a conductor having a work function smaller than that of the member constituting the upper electrode 14 or a semiconductor having a small affinity (electron affinity) with electrons, the electron emission promoting layer 51 can accumulate electrons in the emitter section 13. The amount of electrons supplied from the upper electrode 14 to the emitter section 13 increases. As a result, the number of electrons accumulated in the upper part of the emitter section 13 increases, and the amount of electron emission increases. When the electron emission promoting layer 51 is a fiber-like semiconductor or conductor, the electric field concentration intensity at the tip of the fiber increases when electrons are accumulated in the emitter section 13. As a result, the number of electrons accumulated in the upper part of the emitter section 13 increases, and the amount of electron emission increases. In this case, the conductor is preferably a conductor having a low work function, and the semiconductor is preferably a semiconductor having a low electron affinity.

  As described above, even in the electron emission device including the electron emission promoting layer 51, it is desirable that the average diameter of the through holes 14a of the upper electrode 14 is 10 nm or more and less than 100 nm. In addition, the electron emission promoting layer 51 increases the rate of temperature rise using an infrared heating furnace as in Production Example 4 and Production Example 5 described above (the decomposition process of the organometallic compound occurs during the temperature raising step). (The heating rate is such that it is generated).

Table 1 shows the results of measurement of the difference in the amount of electron emission with and without the electron emission promoting layer 51. Thus, by providing the electron emission promoting layer 51, an extremely large electron emission amount can be obtained.

(Specific example of drive voltage application circuit)
Next, a specific configuration and operation of the drive voltage application circuit 21 described above will be described.

  As shown in FIG. 41, the drive voltage application circuit 21 includes a row selection circuit 21a, a pulse generation source 21b, and a signal supply circuit 21c. In FIG. 41, the symbols D11, D12,... D22, D23, etc. are attached to the above-described one element (electron emitting element constituted by a portion where the upper electrode 14 and the lower electrode 12 overlap). Show. Further, the electron-emitting device 10 in this example includes n elements in the row direction and m elements in the column direction.

  The row selection circuit 21a is connected to the control signal line 100a of the signal control circuit 100 and the positive line 110p and the negative line 110m of the power supply circuit 110. The row selection circuit 21a is further connected to a plurality of row selection lines LL. Each row selection line LL is connected to the lower electrode 12 of a plurality of elements (elements on the same row) forming a group. For example, the row selection line LL1 is connected to the lower electrodes 12 of the elements D11, D12, D13,... D1m in the first row, and the row selection line LL2 is the lower portions of the elements D21, D22, D23,. It is connected to the electrode 12.

  In the charge accumulation period Td in which electrons are accumulated in the emitter section 13 of each element, the row selection circuit 21a responds to a control signal from the signal control circuit 100 for a certain period (row selection line LL). (Period) A selection signal Ss (here, a voltage signal of 50 V) is output only for Ts, and a non-selection signal Sn (here, a voltage signal of 0 V) is output to the remaining row selection lines LL. The row selection circuit 21a sequentially changes the row selection line LL that outputs the selection signal Ss every fixed row selection period Ts.

  The pulse generation source 21b generates a reference voltage (here, 0V) in the charge accumulation period Td, and generates a predetermined constant voltage (here, -400V) in the light emission period (lighting period, electron emission period) Th. It is like that. The pulse generation source 21b is connected between the negative electrode line 110m of the power supply circuit 110 and the ground (GND).

  The control signal line 100b of the signal control circuit 100 and the positive line 110p and the negative line 110m of the power supply circuit 110 are connected to the signal supply circuit 21c. The signal supply circuit 21c includes a pulse generation circuit 21c1 and an amplitude modulation circuit 21c2 inside.

  The pulse generation circuit 21c1 outputs a pulse signal Sp having a constant amplitude (here, 50V) at a constant pulse period in the charge accumulation period Td, and outputs a reference voltage (here, 0V) in the light emission period Th. It is like that.

  The amplitude modulation circuit 21c2 is connected to the pulse generation circuit 21c1 so as to input the pulse signal Sp from the pulse generation circuit 21c1. The amplitude modulation circuit 21c2 is connected to a plurality of pixel signal lines UL. Each of the pixel signal lines UL is connected to the upper electrode 14 of a plurality of elements (elements on the same column) forming a group. For example, the pixel signal line UL1 is connected to the upper electrodes 14 of the elements D11, D21,... Dn1 in the first column, and the pixel signal line UL2 is connected to the upper electrodes 14 of the elements D12, D22,. The pixel signal line UL3 is connected to the upper electrodes of the elements D13, D23,... Dn3 in the third column.

  The amplitude modulation circuit 21c2 modulates the amplitude of the pulse signal Sp according to the luminance level of the pixel in the selected row in the charge accumulation period Td, and the amplitude-modulated signal (here, any of 0, 30, 50V) Voltage signal) is output as a pixel signal Sd to a plurality of pixel signal lines UL (UL1, UL2,... ULm). Further, the amplitude modulation circuit 21c2 outputs the reference voltage (0V) generated by the pulse generation circuit 21c1 as it is during the light emission period Th.

  The signal control circuit 100 receives the video signal Sv and the synchronization signal Sc and, based on these input signals, a signal for controlling the row selection circuit 21a and a signal for controlling the signal supply circuit 21c are supplied to the signal line 100a and the signal line. 100b is output.

  The power supply circuit 110 outputs a voltage signal for making the potential of the positive line 110p higher than the potential of the negative line 110m by a certain voltage (here, 50V) to the positive line 110p and the negative line 110m.

  Next, the operation of the circuit thus configured will be described. First, at the start of the charge accumulation period Td that starts at a certain time, the row selection circuit 21a outputs a selection signal Ss (50V) to the row selection line LL1 of the first row based on a control signal from the signal control circuit 100. Then, the non-selection signal Sn (0 V) is output to the other row selection line LL.

  Accordingly, the potential of each lower electrode 12 of the elements D11, D12, D13,... D1m in the first row becomes the voltage (50 V) of the selection signal Ss. Further, the potentials of the lower electrodes 12 of other elements (for example, the elements D21 to D2m in the second row and the elements D31 to D3m in the third row) become the voltage (0 V) of the non-selection signal Sn.

  At this time, the signal supply circuit 21c is configured by each of the elements in the selected row (that is, the elements D11, D12, D13,... D1m in the first row) based on the control signal from the signal control circuit 100. A pixel signal Sd (here, any voltage signal of 0, 30, 50 V) corresponding to the luminance level of each pixel is output to a plurality of pixel signal lines UL (UL1, UL2,... ULm). The potential difference between the pixel signal Sd and the selection signal Ss becomes the drive voltage Vin.

  In this case, for example, assuming that the pixel signal Sd of 0 V is applied to the pixel signal line UL1, the element voltage Vka (D11) that is a potential difference between the upper electrode 14 and the lower electrode 12 of the element D11 is finally negative. It converges to -50V (= 0V-50V) which is the predetermined voltage Vm. Thereby, a very large number of electrons are accumulated in the emitter section 13 near the upper electrode 14 of the element D11.

  Further, assuming that the pixel signal Sd of 30 V is applied to the pixel signal line UL2, the element voltage Vka (D12) finally becomes −20 V (= 30 V-50 V). Thereby, fewer electrons than the element D11 are accumulated in the emitter section 13 near the upper electrode 14 of the element D12.

  Furthermore, assuming that the pixel signal Sd of 50 V is applied to the pixel signal line UL3, the element voltage Vka (D13) of the element D13 is 0 V (= 50 V−50 V). Accordingly, no electrons are accumulated in the emitter section 13 of the element D13. That is, no polarization inversion occurs in the emitter section 13 of the element D13.

  Next, when a row selection period Ts (a time sufficient for accumulating electrons in the selected element) has elapsed, the row selection circuit 21a performs the row selection line of the second row based on the control signal from the signal control circuit 100. The selection signal Ss is output to LL2, and the non-selection signal Sn (0 V) is output to the other row selection lines.

  Thereby, the potential of each lower electrode 12 of the elements D21, D22, D23,... D2m in the second row becomes the voltage (50 V) of the selection signal Ss. Further, the potentials of the lower electrodes 12 of other elements (for example, the elements D11 to D1m in the first row and the elements D31 to D3m in the third row) become the voltage (0 V) of the non-selection signal Sn.

  On the other hand, the signal supply circuit 21c is configured by each of the elements in the selected row (that is, the elements D21, D22, D23,... D2m in the second row) based on the control signal from the signal control circuit 100. A pixel signal Sd (a voltage signal of 0, 30, or 50 V) corresponding to the luminance level of each pixel is output to a plurality of pixel signal lines UL (UL1, UL2,... ULm). As a result, an amount of electrons corresponding to the pixel signal Sd is accumulated in the emitters of the elements D21, D22, D23,... D2m in the second row.

  The element voltage Vka of the element to which the voltage (0V) of the non-selection signal Sn is applied to the lower electrode is 0V (in this case, the upper electrode potential = 0V, the lower electrode potential = 0V), 30V (in this case, The potential of the upper electrode = 30V, the potential of the lower electrode = 0V) or 50V (in this case, the potential of the upper electrode = 50V, the potential of the lower electrode = 0V), but electrons are already accumulated at this level of voltage. No polarization inversion of the element occurs and no electrons are emitted from the element.

  Further, when the row selection period Ts elapses, the row selection circuit 21a outputs the selection signal Ss to the row selection line LL3 (not shown) of the third row and the non-selection signal Sn (0 V) to the other row selection lines. Is output. In addition, the signal supply circuit 21c outputs pixel signals Sd corresponding to the luminance levels of the respective pixels configured by the selected elements in the third row to the plurality of pixel signal lines UL. Such an operation is repeated until all rows are selected every time the row selection period Ts elapses. As a result, at a predetermined point in time, electrons (amount including “0”) corresponding to the luminance level of the pixels formed by the respective elements are accumulated in the emitter sections 13 of all the elements. The above is the operation in the charge accumulation period Td.

  Next, the row selection circuit 21a generates a large negative voltage (here, + 50V generated by the power supply circuit 110 and the pulse generation source 21b) with respect to all the row selection lines LL in order to start the light emission period Th. -350V) which is a difference of -400V is applied. As a result, the potentials of the lower electrodes 12 of all the elements change to a large negative voltage (−350 V). At the same time, the signal supply circuit 21c outputs the reference voltage (0 V) generated by the pulse generation circuit 21c1 through the amplitude modulation circuit 21c2 to all the pixel signal lines UL as it is. Thereby, the potentials of the upper electrodes 14 of all the elements become the reference voltage (0 V).

  As a result, the polarization inversion occurs again, and the electrons accumulated in the emitter portions 13 of the respective elements are emitted all at once by the Coulomb repulsive force. As a result, the phosphor located above each element emits light, and an image is displayed. In the emitter portion of the element that has not accumulated electrons due to the drive voltage Vin being “0” during the charge accumulation period Td, no polarization inversion has occurred, so that the drive voltage Vin has a large positive voltage. When this occurs, polarization inversion does not occur. Therefore, for example, an element that does not need to emit electrons due to an image relationship at a certain timing does not consume useless power associated with polarization inversion.

  As described above, the drive voltage application circuit 21 sequentially sets the drive voltage Vin for each of the plurality of elements as the first voltage Vm, which is a negative predetermined voltage, sequentially in the charge accumulation period Td. Thereafter, when the operation of accumulating electrons for all the elements is completed, the drive voltage applying circuit 21 simultaneously sets the drive voltage Vin for all the elements as the second voltage Vp, which is a positive predetermined voltage, for all the plurality of elements. The electrons are emitted all at once and the light emission period Th is started. Further, thereafter, when a predetermined light emission period Th elapses, the drive voltage application circuit 21 starts the charge accumulation period Td again.

  As described above, since the electron emitting device according to the present invention has fine through holes with an average diameter of 10 to 100 nm formed in the upper electrode, more electrons can be efficiently emitted. In addition, this invention is not limited to the said embodiment, A various modification can be employ | adopted within the scope of the present invention.

  For example, as shown in FIG. 42, the electron emission apparatus 20 according to the modification of the present invention is an apparatus in which the collector electrode 18 and the phosphor 19 of the electron emission apparatus 10 are replaced with the collector electrode 18 ′ and the phosphor 19 ′. is there.

  In the electron emission device 20, a phosphor 19 'is formed on the back surface (the surface facing the upper electrode 14) of the transparent plate 17, and a collector electrode 18' is formed so as to cover the phosphor 19 '. The collector electrode 18 ′ is formed to have a thickness that allows electrons emitted from the emitter section 13 through the through hole 14 a of the upper electrode 14 to penetrate. In this case, it is desirable that the collector electrode 18 'has a thickness of 100 nm or less. The thickness of the collector electrode 18 'can be increased as the kinetic energy of the emitted electrons increases.

  Such a configuration is a configuration employed in a CRT or the like. The collector electrode 18 'functions as a metal back. Electrons emitted from the emitter section 13 through the through-hole 14a of the upper electrode 14 penetrate the collector electrode 18 'and enter the phosphor 19' to excite the phosphor 19 'and produce light emission. The electron emission device 20 can achieve the following effects.

(A) When the phosphor 19 ′ is not conductive, the phosphor 19 ′ can be prevented from being charged (negatively charged). As a result, an electric field that accelerates electrons can be maintained.
(B) Since the light generated by the phosphor 19 ′ is reflected by the collector electrode 18 ′, the light can be efficiently emitted to the transparent plate 17 side (light emitting surface side).
(C) Since excessive collision of electrons with the phosphor 19 ′ can be prevented, deterioration of the phosphor 19 ′ and generation of gas from the phosphor 19 ′ can be avoided.

  In addition, as shown in FIG. 43, the electron emission device according to another modification of the present invention includes not only the upper electrodes 14 adjacent to each other in the X-axis direction but also the Y-axis. It is also formed between the upper electrodes 14 adjacent to each other in the direction.

  According to this, the electrons emitted from the upper electrode 14 of a certain element do not reach the phosphor above the upper electrode 14 of another element adjacent in the X-axis direction. Therefore, the color purity can be maintained satisfactorily. Further, in this example, since the focusing electrode 16 is formed between the upper electrodes 14 of two elements adjacent to each other in the Y-axis direction, electrons emitted from a certain upper electrode 14 are adjacent in the Y-axis direction. The phosphor above the upper electrode 14 does not reach. As a result, it is possible to avoid bleeding of the image pattern.

  Furthermore, as shown in FIG. 44, the electron-emitting device according to the present invention includes four elements (thus, four upper electrodes 14, the first upper electrode 14-1 and the second upper electrode 14-2, in one substantially square pixel PX. The upper electrode 14-2, the third upper electrode 14-3, the fourth upper electrode 14-4), and the focusing electrode 16 may be provided. In this case, for example, a green phosphor (not shown) is disposed immediately above the first upper electrode 14-1, and a red phosphor (not shown) is directly above the second upper electrode 14-2 and the fourth upper electrode 14-4. A blue phosphor (not shown) is disposed immediately above the third upper electrode 14-3. The focusing electrode 16 is formed around each upper electrode 14 so as to surround each upper electrode 14. According to this, since the electrons emitted from the upper electrode 14 of a certain element reach only the phosphor disposed immediately above the upper electrode 14, the color purity is maintained well and the blurring of the image pattern is avoided. be able to.

  Furthermore, although the electron-emitting device of the said embodiment was provided with the focusing electrode and the power supply (focusing electrode potential provision circuit) with respect to the focusing electrode, you may abbreviate | omit these. In addition, the phosphor included in the electron emission device is not limited to a red phosphor, a green phosphor, and a blue phosphor, and may be, for example, a white phosphor. In addition, although the electron emission device of the above embodiment is disclosed as a display including a focusing electrode, a collector electrode, a transparent plate, a phosphor, and the like, it is not necessary to include these. That is, the electron-emitting device according to the present invention may be a single electron-emitting device that includes an emitter, an upper electrode, and a lower electrode and emits electrons. Such an electron emission device (electron emission element) can be applied to a wide range of devices such as an electron irradiation device, a light source, an LED substitute, an electronic component manufacturing device, and an electronic circuit component.

  As described above, each embodiment of the electron-emitting device according to the present invention includes an upper electrode having a through-hole having an average diameter of 10 nm or more and less than 100 nm, so that electron emission can be performed with high efficiency. In addition, the straightness of electrons is excellent. Therefore, this electron emission device can be suitably used not only for a direct-view type thin television but also for a small display built in a front projection or rear projection projector. For example, if a three-sided small display corresponding to the three primary colors of RGB is prepared, a high-detail television can be configured with 0.2 mm pitch pixels that can be formed by pressure film printing. At this time, the electron emission device according to the present invention has a feature that a display can be made thinner than a CRT projector, and a high-output light source is not required separately as compared with an LCD and a DMD projector. Therefore, the electron-emitting device according to the present invention can provide not only space saving but also an advantage that it is super-long-life and maintenance-free because it is not necessary to replace the high-power light source.

It is a fragmentary sectional view of the electron emission apparatus concerning the embodiment of the present invention. It is the fragmentary sectional view which cut | disconnected the electron emission apparatus shown in FIG. 1 in a different plane. FIG. 2 is a partial plan view of the electron emission device shown in FIG. 1. FIG. 2 is an enlarged partial cross-sectional view of the electron emission device shown in FIG. 1. FIG. 2 is an enlarged partial plan view of an upper electrode shown in FIG. 1. It is the figure which showed the example of the other through-hole of the upper electrode shown in FIG. It is the figure which showed the example of the other through-hole of the upper electrode shown in FIG. It is the figure which showed the example of the other through-hole of the upper electrode shown in FIG. It is the figure which showed the example of the other through-hole of the upper electrode shown in FIG. It is the figure which showed the example of the other through-hole of the upper electrode shown in FIG. It is an expanded sectional view of the upper electrode and emitter part which were shown in FIG. It is the figure which showed one state of the electron emission apparatus shown in FIG. It is a graph of the voltage-polarization characteristic of the emitter part shown in FIG. It is the figure which showed the other state of the electron emission apparatus shown in FIG. It is the figure which showed the other state of the electron emission apparatus shown in FIG. It is the figure which showed the other state of the electron emission apparatus shown in FIG. It is the figure which showed the other state of the electron emission apparatus shown in FIG. It is the figure which showed the other state of the electron emission apparatus shown in FIG. It is the figure which showed the mode of the electron discharge | released by the electron emission apparatus which is not provided with a focusing electrode. It is the figure which showed the mode of the electron discharge | released by the electron emission apparatus shown in FIG. It is an enlarged photograph of the upper electrode surface of the electron emission apparatus manufactured by the manufacturing method example 1 of this invention. It is an enlarged photograph of the upper electrode surface of the electron emission apparatus manufactured by the manufacturing method which does not apply this invention. It is an enlarged photograph of the upper electrode surface of the electron emission apparatus manufactured by the manufacturing method example 2 of this invention. It is an enlarged photograph of the upper electrode surface of the electron emission apparatus manufactured by the manufacturing method example 3 of this invention. It is the graph which showed the relationship between the average diameter of the through-hole of an upper electrode, and the quantity of the discharge | released electron. It is the figure which showed the mode of the electric field formed at the time of electron accumulation in the electron emission apparatus shown in FIG. FIG. 27A is a diagram for explaining the length of the peripheral portion of the through hole having a large diameter, and FIG. 27B is a diagram for explaining the length of the peripheral portion of the through hole having a small diameter. FIG. It is an enlarged photograph of the upper electrode surface of the electron emission apparatus manufactured by the manufacturing method example 4 of this invention. It is the further enlarged photograph of the upper electrode surface of the electron emission apparatus manufactured by the manufacturing method example 4 of this invention. It is the graph which showed the electron emission characteristic of the electron emission apparatus manufactured by the manufacturing method example 4 of this invention. It is the graph which showed the electron emission characteristic of the electron emission apparatus manufactured by the manufacturing method example 4 of this invention. It is a graph which shows the relationship between the temperature rising rate of the electron emission apparatus which has the upper electrode manufactured by changing temperature rising rate, and the amount of electron emission. It is an enlarged photograph of the upper electrode surface of the electron-emitting apparatus manufactured by the other manufacturing method example of this invention. It is an enlarged photograph of the upper electrode surface of the electron emission apparatus manufactured by the manufacturing method example 5 of this invention. It is a graph which shows the relationship between the emitted-heat amount when an organometallic compound is heated, and the temperature of the organometallic compound. It is a graph which shows the change of the amount of electron emission with respect to the frequency | count of electron emission about the electron emission apparatus which has the upper electrode baked with the low temperature increase rate, and the electron emission apparatus which has the upper electrode baked with the high temperature increase rate. It is the fragmentary sectional view of the upper electrode baked with the low temperature increase rate, and its vicinity part. It is the fragmentary sectional view of the upper electrode baked with the high temperature increase rate, and its vicinity part. It is the figure which showed the infrared heating furnace. It is an expanded partial sectional view of the electron emission apparatus which concerns on other embodiment of this invention. FIG. 2 is a circuit diagram of a drive voltage application circuit shown in FIG. 1. It is a fragmentary sectional view of the modification of the electron emission apparatus by this invention. It is a fragmentary top view of the other modification of the electron emission apparatus by this invention. It is a fragmentary top view of the other modification of the electron emission apparatus by this invention. It is the fragmentary sectional view which showed one state of the electron emission apparatus regarding this invention. It is the fragmentary sectional view which showed the other state of the electron emission apparatus regarding this invention. It is the fragmentary sectional view which showed the other state of the electron emission apparatus regarding this invention. It is the fragmentary sectional view which showed the other state of the electron emission apparatus regarding this invention. It is the figure which showed the mode of the electric field formed at the time of electron accumulation in the conventional electron emission apparatus. It is a partial expanded sectional view of the upper electrode with favorable flatness. It is a partial expanded sectional view of the upper electrode with poor flatness.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10,20 ... Electron emission apparatus, 11 ... Board | substrate, 12 ... Lower electrode, 13 ... Emitter part, 14 ... Upper electrode, 14a-14f ... Through-hole, 15 ... Insulating layer, 16 ... Focusing electrode, 17 ... Transparent plate, 18 ... collector electrode, 19 ... phosphor.

Claims (8)

An emitter portion made of a dielectric, a lower electrode formed at a lower portion of the emitter portion, and an upper electrode formed at an upper portion of the emitter portion so as to face the lower electrode with the emitter portion interposed therebetween. In the electron emission device that emits electrons from the emitter through the upper electrode by applying a driving voltage between the lower electrode and the upper electrode,
The upper electrode is
A plurality of through- holes that expose the emitter part are formed, and a peripheral surface of the through-hole and facing the emitter part is formed so as to be separated from the emitter part by a predetermined distance,
The electron emission device according to claim 1, wherein an average diameter of the through holes is smaller than a particle diameter of a dielectric of the emitter section. The electron emission device according to claim 1, wherein
The electron emission apparatus according to claim 1, wherein the upper electrode includes a metal, and the through hole is a pore formed of metal crystal grains of the metal. The electron-emitting device according to claim 1 or 2 ,
The upper electrode is an electron emission device comprising two or more kinds of metals. The electron emission device according to claim 3 , wherein
The upper electrode is an electron emission device comprising two or more kinds of metals of silver, gold, iridium, rhodium, ruthenium, platinum, palladium, aluminum, copper, nickel, chromium, molybdenum, tungsten and titanium. 5. The electron emission device according to claim 4 , wherein
The upper electrode is an electron emission device using platinum as a base material. The electron emission device according to any one of claims 1 to 5 ,
The electron emission device according to claim 1, wherein the upper electrode has a three-dimensional network structure formed by bonding metal particles. The electron emission device according to any one of claims 1 to 5 ,
The electron emission device according to claim 1, wherein the upper electrode is a porous body formed by chemically bonding two or more metal particles in the thickness direction. The electron emission device according to any one of claims 1 to 7 ,
An electron-emitting device in which the average aperture ratio of the upper electrode is 5% or more and 60% or less.