JP2000138095A - Manufacture of light emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate thickness irregularity to uniformize light emitting, by adding a process for depositing the same material from two or more depositing sources to a manufacturing process for placing a substance for emitting light between a positive electrode and a negative electrode so as to emit light with electric energy. SOLUTION: A light emitting device is formed by filling a substance for emitting light composing a host material, a light emitting material and a positive hole transporting material containing dopant with this, a multi-layer laminated body with an electron transporting material, and mixture in-between a positive electrode such as ITO glass and a negative electrode such as low work function. When, for example, the positive hole transporting material and an electron transporting luminescent layer is deposited in a resistance heating method, as a dry-type film on a flat substrate 1, four depositing sources 3 are arranged to eliminate thickness irregularity of a deposited object 2. Preferably, each depositing source 3 is independently controlled by a film thickness monitor or an independent source, adjustment of depositing rate eliminates film thickness difference between a central part and an end part, and the substrate 1 can be moved. Rotation of the substrate 1 during deposition is useful, and required space in vacuum is small.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an element capable of converting electric energy into light, and relates to a display element, a flat panel display, a backlight, lighting, an interior, a sign, a sign, an electrophotographic device, and an optical signal. The present invention relates to a method for manufacturing a light emitting element that can be used in a field such as a generator.

[0002]

2. Description of the Related Art In recent years, active research has been conducted on organic thin-film light emitting devices that emit light when electrons injected from a negative electrode and holes injected from a positive electrode recombine in an organic phosphor sandwiched between both electrodes. I have. This element is characterized by thinness, high luminance light emission under a low driving voltage, and multicolor light emission by selecting a fluorescent material.

[0003] It is known from Kodak's C.I. W. Tang et al. (Appl. Phys. Lett. 51 (12)
21, p. 913, 1987). A typical configuration of the organic laminated thin-film light emitting device presented by Kodak Company is a hole transporting diamine compound and a light emitting layer on an ITO glass substrate,
8-Hydroxyquinoline aluminum, which also has an electron transporting property, and Mg: Ag as a negative electrode were sequentially provided, and green light emission of 1000 candela / m 2 was possible at a driving voltage of about 10 V. The current organic laminated thin-film light-emitting device has a different configuration, such as a device provided with an electron transport layer, in addition to the above-described device components, but basically follows the configuration of Kodak. I have. In recent years, sealing has been performed to improve durability,
A protective layer may be provided before sealing.

A method of forming a thin film of an organic laminated thin film light emitting device (hereinafter referred to as a light emitting device) includes a dry film forming system such as a resistance heating evaporation method and an electron beam evaporation method, and a dip coating method and a spin casting method. It can be broadly divided into wet film forming systems. However, since the wet film forming system is operated in the atmosphere, foreign matters are easily mixed in, and moisture and the like are easily adsorbed to the interface, and thus the characteristics of the light emitting element are easily adversely affected. On the other hand, the dry film forming method does not have the above-mentioned adverse effects, and a good thin film can be obtained. Therefore, it is generally necessary to use a dry film forming system for all or a part of the thin film forming process. It is considered to be preferable in terms of various characteristics such as durability and durability.

Here, the thickness of the layer of the substance which controls light emission of the light emitting element is not limited because it depends on the resistance value and the like, but can be selected from the range of 10 to 1000 nm. Since a very thin film is laminated, the thickness unevenness has a serious adverse effect on the light emitting device. Specifically, light emission unevenness occurs due to variation in resistance, and in severe cases, an electric field concentrates on a thin portion, thereby destroying the element, causing a non-light emitting portion due to a short circuit and a reduction in luminous efficiency. In addition, moisture or the like enters from the destroyed portion, and the non-light-emitting portion expands, affecting the durability.

When a dry film forming system is used in the manufacturing process of the light emitting device, the deposits are uniformly scattered radially from a point-like deposition source. On the other hand, since a general substrate is flat, the distance from the evaporation source varies depending on the location, and thickness unevenness occurs. Therefore, in order to prevent the film thickness unevenness, a device for moving the substrate by rotation or the like to equalize the thickness unevenness has been made. While this technique worked,
In consideration of productivity, devices can be manufactured simultaneously on multiple substrates,
As substrates have become larger, they have become less than satisfactory. The thickness unevenness has an adverse effect not only on the layer that controls light emission but also on the electrodes and the protective layer.

Further, pattern processing in a dry film forming system is often performed using a shadow mask. However, in order to cope with a fine pattern, the mask portion sandwiched between the openings becomes thin like a thread, and the strength is reduced. , The accuracy of the pattern shape tends to deteriorate. Therefore, a shadow mask provided with a reinforcing line for preventing deformation of the opening has come to be used.However, a shadowed portion is generated by the reinforcing line, and the vapor deposition pattern is divided, particularly in forming an electrode. , Conduction cannot be obtained. This can be prevented to some extent by utilizing the wraparound phenomenon of the deposit by floating the reinforcing wire from the deposition surface, but a method of effectively wrapping the deposit is desired.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the problems of the prior art and to provide a method for manufacturing a light emitting device capable of obtaining uniform light emission without thickness unevenness.

[0009]

According to the present invention, there is provided an element which emits light by electric energy between a positive electrode and a negative electrode. A method for manufacturing a light-emitting element, comprising the step of vapor deposition from the vapor deposition source described above.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION A positive electrode according to the present invention is made of a conductive metal oxide such as tin oxide, indium oxide, indium tin oxide (ITO), or gold, silver, chromium, if it is transparent to extract light. Such metals, copper iodide, inorganic conductive substances such as copper sulfide, and conductive polymers such as polythiophene, polypyrrole, and polyaniline are not particularly limited. However, it is preferable to use ITO glass or Nesa glass. It is desirable to use. The resistance of the transparent electrode is not limited as long as a current sufficient for light emission of the element can be supplied, but is preferably low from the viewpoint of power consumption of the element. For example, 300Ω /
If it is an ITO glass substrate of □ or less, it functions as an element electrode, but it is now possible to supply a substrate of about 10 Ω / □, so it is particularly preferable to use a low-resistance substrate of 20 Ω / □ or less. desirable. The thickness of the ITO can be arbitrarily selected according to the resistance value.
Often used between nm. Further, as the glass substrate, soda lime glass, non-alkali glass or the like is used, and the thickness only needs to be sufficient to maintain the mechanical strength. As for the material of the glass, alkali-free glass is preferred because it is better that ions eluted from the glass are small.
Soda lime glass having a barrier coat such as No. 2 is also commercially available and can be used. Even when a substrate other than glass is used, any substrate may be used as long as it is transparent and has a high sealing effect. It is desirable that the ITO glass substrate be well cleaned and well dried.

In the present invention, the structure of the substance that controls light emission is as follows:
1) a hole transporting material / a light emitting material, 2) a hole transporting material / a light emitting material / an electron transporting material, 3) a light emitting material / an electron transporting material, and 4) a form in which a combination of the above substances is mixed.
Any of these may be used. That is, in addition to the multilayered structures 1) to 3), a layer containing a luminescent material alone or a luminescent material and a hole transporting material, or a layer containing a luminescent material, a hole transporting material and an electron transporting material as in 4) is further provided. It may just be provided. The light emitting material may be either a host material alone or a combination of a host material and a dopant material.
In addition, the dopant material may be included in the entire host material, partially, or may be included. The dopant material may be stacked, dispersed, or the like.

The hole transporting material in the present invention is required to efficiently transport holes from the positive electrode between the electrodes to which an electric field is applied, and has a high hole injection efficiency. Good transport is desirable. For that purpose, it is required that the ionization potential be small, the hole mobility be large, the stability be further improved, and impurities serving as traps be hardly generated during production and use. The substance satisfying such conditions is not particularly limited, but is a biscarbazolyl derivative,
Known triphenylamine derivatives such as TPD, m-MTDATA, α-NPD, pyrazoline derivatives, stilbene compounds, hydrazone compounds, heterocyclic compounds represented by oxadiazole derivatives and phthalocyanine derivatives, polyvinyl carbazole, polysilane and the like Hole transport materials can be used. These hole transport materials may be used alone or may be laminated or mixed with different hole transport materials.

Among the luminescent materials in the present invention, the host material is not particularly limited, but tris (8-quinolinolato) aluminum, a condensed ring derivative such as anthracene or pyrene, which has been known as a luminescent material before, may be used. Metal chelated oxinoid compounds, bisstyryl derivatives such as bisstyrylanthracene derivatives and distyrylbenzene derivatives, tetraphenylbutadiene derivatives, coumarin derivatives, oxadiazole derivatives, pyrrolopyridine derivatives, perinone derivatives, cyclopentadiene derivatives, oxadiazole For derivatives, thiadiazolopyridine derivatives, and polymer systems, polyphenylenevinylene derivatives, polyparaphenylene derivatives, and polythiophene derivatives can be used.

The dopant material to be added to the host material is not particularly limited, but specific examples thereof include condensed ring derivatives such as perylene and rubrene, quinacridone derivatives, phenoxazone 660, DC
M1, perinone, coumarin derivatives and the like can be used as they are. These dopant materials may be used alone or in combination with different dopant materials.

As the electron transporting material in the present invention,
It is necessary to efficiently transport electrons from the negative electrode between the electrodes to which an electric field is applied, and it is desirable that the electron injection efficiency is high and the injected electrons are transported efficiently. For this purpose, it is required that the material has a high electron affinity, a high electron mobility, a high stability, and a small amount of impurities serving as traps during production and use. Materials satisfying such conditions include quinolinol derivative metal complexes represented by 8-hydroxyquinoline aluminum, tropolone metal complexes, flavonol metal complexes, perylene derivatives, perinone derivatives, naphthalene,
There are coumarin derivatives, oxadiazole derivatives, aldazine derivatives, bisstyryl derivatives, pyrazine derivatives, phenanthroline derivatives, and the like, but are not particularly limited. Although these electron transport materials are used alone,
They may be laminated or mixed with different electron transport materials.

The negative electrode of the present invention efficiently converts electrons,
The substance is not particularly limited as long as it can be injected into the substance that controls light emission. Generally, platinum, gold, silver, copper, iron, tin, aluminum, indium, lithium, sodium, potassium,
Examples include calcium and magnesium. In order to increase the electron injection efficiency and improve the device characteristics, a low work function metal such as lithium, sodium, potassium, calcium, and magnesium is effective. However, since these low work function metals are generally unstable, it is desirable to form an alloy or a laminated structure with the stable metal. Alternatively, a method of doping a substance which controls light emission is also effective.

The light emitting device of the present invention may be sealed. Before that, a protective layer may be provided to protect the light-emitting element. Platinum,
Metals such as gold, silver, copper, iron, tin, lead, aluminum, titanium, nickel, and indium, or alloys using these metals, and silica, titania, alumina, magnesium oxide, yttrium oxide, germanium oxide, and nickel oxide , Barium oxide, calcium oxide, metal oxides such as iron oxide, magnesium fluoride, lithium fluoride, aluminum fluoride, metal fluorides such as calcium fluoride, resins such as fluororesins, and the like. It is not limited.

The method of sealing in the present invention is a method in which a light emitting element is put in a container made of a sealing material and sealed with an adhesive, or a method in which the light emitting element is bonded to a substrate on which the light emitting element is formed by sandwiching it with a thin sealing material. Examples include a method of sealing with an agent, but the method is not particularly limited.

The sealing material is not particularly limited as long as it prevents moisture from entering the light emitting element. Specifically, soda-lime glass, borosilicate glass, silicate glass, silica glass, non-fluorescent glass, quartz, inorganic substances such as ceramics, metals such as stainless steel and aluminum alloy, fluorine resin, acrylic resin, Polycarbonate resin, epoxy resin, polyester resin, polyamide resin, polystyrene resin, polyethylene resin, polypropylene resin, polyolefin resin,
Examples include resins such as silicone resins.

The adhesive used for sealing is not particularly limited as long as it has a sealing effect. In particular,
An epoxy resin-based adhesive, an acrylate resin-based adhesive, or the like can be used. In addition, a photocurable resin adhesive, a thermosetting resin adhesive, an anaerobic resin adhesive, or the like can be used.

An adsorbent may be included between the light emitting element and the sealing material. The adsorbent is not particularly limited as long as it adsorbs moisture that enters from outside after sealing. Specifically, activated alumina, diatomaceous earth, activated carbon, phosphorus pentoxide, magnesium perchlorate, potassium hydroxide, calcium nitrate, calcium bromide, calcium oxide, barium oxide, barium carbonate, zinc chloride, zinc bromide, sulfuric anhydride Examples include inorganic compounds such as copper, metals such as lithium, beryllium, potassium, sodium, magnesium, rubidium, strontium, and calcium and alloys thereof, and acrylic and methacrylic water-absorbing polymers.

The method for forming a thin film of a light emitting device in the present invention is not particularly limited, and a wet film forming method such as a dip coating method, a spin casting method, a molecular laminating method, and an electrolytic polymerization method can be partially used. However, since the dry film forming method is preferable in terms of characteristics, it is used in all or at least a part of the thin film forming process. As a dry film forming method,
Examples thereof include a resistance heating evaporation method, an electron beam evaporation method, an ion plating method, a sputtering method, and a CVD method, and the resistance heating evaporation method, the electron beam evaporation method, and the sputtering method can be easily used.

FIG. 1 shows the uniformity of the film thickness when vapor deposition is performed on a wide substrate surface in the case where one vapor deposition source is used. For the sake of convenience, the film thickness non-uniformity in the left-right direction is considered, ignoring the direction perpendicular to the paper. Ideally, the deposit 2 is uniformly and radially emitted from the deposition source 3 as shown in the lower part of FIG. That is, the closer to the deposition source, the more deposited material is deposited. Since the substrate 1 is a flat surface, the distance from the deposition source is closer to the center and closer to the end, so that the film thickness distribution is schematically shown in the upper part of FIG. That is, the film thickness at the end of the substrate away from the center is considerably smaller than at the center.

In order to reduce the film thickness unevenness, there is a means for increasing the distance between the substrate and the vapor deposition source so that the difference between the distance between the substrate center and the vapor deposition source and the distance between the substrate end and the vapor deposition source can be ignored. In addition, it is necessary to increase the size of the apparatus, and it is not possible to effectively use the deposits discharged from the deposition source.

Therefore, in the present invention, the same material is vapor-deposited from two or more vapor deposition sources on all or a part of a layer formed by a dry method in order to prevent thickness unevenness when forming a thin film. For example, considering the case where four evaporation sources 3 are arranged as shown in the lower part of FIG. 2, since the evaporation object 2 is dispersedly deposited from each of the evaporation sources, thickness unevenness is eliminated. This is schematically as shown in FIG. That is, a film thickness close to the center can be obtained even at the end of the substrate away from the center. When four evaporation sources 3 are arranged as shown in the lower part of FIG. 3 and the evaporation rate of the evaporation sources 3 at both ends is further increased to achieve a good balance, the thickness unevenness is further eliminated, and the film thickness is reduced. The thickness distribution is schematically as shown in the upper part of FIG. For this reason, it is preferable that the evaporation sources be controlled independently. Although the control of the evaporation source is not particularly limited, it can be performed by making the film thickness monitor and the power source independent, or may be controlled by providing a correction plate. It is also possible to combine a plurality of control methods.

In order to further increase the effect, it is preferable to perform the vapor deposition while moving the substrate. This is to make the film thickness unevenness uniform by moving the substrate. The method of moving the substrate is not particularly limited, and examples thereof include a movement in only one direction parallel to the evaporation source or a reciprocating and reciprocating movement, a movement along a polygonal side, a circumference, and an ellipse. The movement may be linear, meandering, or polygonal. Since the vapor deposition is performed in a vacuum, it is desirable that the space to be moved is not large. In order to move the substrate compactly and sufficiently in the vapor deposition apparatus, a method of rotating the substrate is preferable. The rotation speed is not particularly limited, but is preferably at least one rotation during vapor deposition. Further, the rotation speed may be constant or changed, and may be intermittently rotated or reversed. The rotation axis of the deposition source and the substrate is not particularly limited, but it is preferable that the substrate and the deposition source do not overlap on the rotation axis at the same time. The substrate may be rotated, revolved, or revolved while rotating. Since it is important that they move relatively, the substrate may be essentially fixed and the evaporation source may be moved.

The deposition rate is not particularly limited, but may be 100% per second, which is a normal deposition rate.
It can be deposited at a thickness of about 1 nm to about 30 nm. Further, as described above, the evaporation rates of the evaporation sources may be the same or different. In general, the deposition rate can be increased to some extent by increasing the deposition temperature. However, there is a concern that increasing the deposition temperature may affect the deposited material such as decomposition. In the step of depositing the same material from two or more deposition sources, the time required to form a required film thickness can be reduced by increasing the deposition rate without increasing the temperature of the deposition source, and from the viewpoint of productivity. Is also effective.

There is no particular limitation on the mutual arrangement of the evaporation sources, the positional relationship with the substrate, and the like. The balance is adjusted so that other parameters during evaporation, such as the evaporation speed, and as a result, the film thickness unevenness is suppressed. Is preferred. The distances between the evaporation source and the substrate may be the same or different, and the evaporation sources may be arranged offset or averagely. In the method of averaging, there is no particular limitation such as point symmetry and line symmetry, such as arranging at the vertices of a regular polygon such as an equilateral triangle or square, arranging on a circumference, equally spaced lines Although a method of arranging in a minute or square shape can be mentioned, it is not particularly limited.

The method for supplying the deposition material to the deposition source is not particularly limited, and may be a batch type or a continuous supply.

The material and shape of the evaporation source are not particularly limited, and filaments such as tungsten, molybdenum, tantalum and niobium, baskets and boats, and crucibles such as alumina and BN can be used. Can be used.

There is no particular limitation on the number of substrates to be arranged, and one substrate may be set, a plurality of substrates may be set, or multiple substrates may be formed. The inclination of the substrate with respect to the deposition source is not particularly limited, and may be parallel or inclined. The size of the substrate is not particularly limited, but the effect of the present invention is great when the substrate size is large, or when the substrate is multi-panned and vapor-deposited on a large area at once.

Among the layers constituting the light emitting element, in the substance which controls light emission, uneven light emission occurs due to variation in resistance, and in severe cases, the element is destroyed due to concentration of an electric field on a thin portion, and non-light emission due to short circuit occurs. The thickness unevenness has a large effect on the light-emitting element, such as the occurrence of a portion or a decrease in luminous efficiency, or the invasion of moisture or the like from the destroyed portion, and the non-light-emitting portion expands and affects the durability. Therefore, the effect is the largest. The thickness unevenness of the electrode is also effective because it causes adverse effects such as light emission unevenness and disconnection, and the thickness unevenness of the protective layer is also effective because it causes distortion due to volume change. In addition, the vapor deposition method of the present invention is suitably used for both formation of a light emitting portion using a light emitting material and formation of an electrode, but is more effective for forming a light emitting portion.

The pattern formation of the light emitting element in the present invention is not particularly limited, but it is preferable to use a shadow mask. In order to cope with a fine pattern, it is more preferable to use a shadow mask provided with a reinforcing line for preventing deformation of the opening. Here, when forming a negative electrode using a shadow mask provided with a reinforcing wire, the vapor deposition method of the present invention is very effective. The reinforcing line shadow mask has a problem that a shadowed portion is generated by the reinforcing line and the vapor deposition pattern is divided. In order to avoid this, the wraparound phenomenon of the deposited material is used by floating the reinforcing wire from the deposition surface. The deposition method of the present invention,
The method is more effective because the deposited material is effectively wrapped around. In addition to the above, the present invention is effective because the effect of thickness unevenness due to the reinforcing wire greatly affects the wiring resistance.

The electric energy in the present invention mainly refers to a direct current, but it is also possible to use a pulse current or an alternating current. The current value and voltage value are not particularly limited,
In consideration of the power consumption and life of the device, it is necessary to obtain the maximum brightness with the lowest possible energy.

It is preferable that the light emitting device of the present invention constitutes a display for displaying by a matrix or segment system or a combination of both.

The matrix according to the present invention refers to a matrix in which pixels for display are arranged in a lattice, and displays a character or an image by a set of pixels. The shape and size of the pixel depend on the application. For example, for the display of images and characters on personal computers, monitors, televisions, and the like, generally square pixels with a side of 300 μm or less are used, and in the case of a large display such as a display panel, pixels with a side on the order of mm are used. Become. In the case of monochrome display, pixels of the same color may be arranged, but in the case of color display, red, green and blue pixels are displayed side by side. In this case, there are typically a delta type and a stripe type. Note that the light-emitting element of the present invention can emit red, green, and blue light, so that multi-color or full-color display can be performed by using the display method. The matrix may be driven by either a line-sequential driving method or an active matrix. The line-sequential driving has the advantage of a simpler structure, but the active matrix is sometimes superior in consideration of the operating characteristics. Therefore, it is necessary to use this depending on the application.

In the segment type according to the present invention, a pattern is formed so as to display predetermined information, and a predetermined area emits light. For example, there are a time display and a temperature display on a digital clock or a thermometer, an operation state display of an audio device, an electromagnetic cooker, or the like, and a panel display of an automobile. The matrix display and the segment display may coexist in the same panel.

The light emitting device of the present invention is also preferably used as a backlight. The backlight in the present invention,
It is mainly used for improving the visibility of a display device that does not emit light, and is used for a liquid crystal display device, a clock, an audio device, an automobile panel, a display panel, a sign, and the like. In particular, as for the backlight for liquid crystal display devices, particularly for personal computer applications where thinning is an issue, the present invention is considered to be difficult because the conventional type is made of a fluorescent lamp or a light guide plate, and it is difficult to make it thin. Is characterized by its thinness and light weight.

[0039]

The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited to these examples. Example 1 A glass substrate (15 Ω / □, manufactured by Asahi Glass Co., electron beam evaporation product) on which an ITO transparent conductive film was deposited to a thickness of 150 nm
It was cut into 0 × 150 mm and patterned by photolithography into 300 μm pitch (remaining width 270 μm) × 640 stripes. The obtained substrate was subjected to ultrasonic cleaning with acetone and semicocrine 56 for 15 minutes each, and then with ultrapure water. Subsequently, the substrate was subjected to ultrasonic cleaning with isopropyl alcohol for 15 minutes, immersed in hot methanol for 15 minutes, and dried. This substrate was subjected to UV-ozone treatment for one hour immediately before the device was manufactured, placed in a vacuum evaporation apparatus, and evacuated until the degree of vacuum in the apparatus became 5 × 10 ⁻⁴ Pa or less. Set the evaporation source (tungsten boat) at two places, rotate the substrate, and use the resistance heating method.
First, 150 nm of 4,4′-bis (N- (m-tolyl) -N-phenylamino) biphenyl was used as a hole transport material.
In the same manner, vapor deposition sources were set at two places, and trisquinolinolate aluminum (III) was vapor deposited to a thickness of 100 nm as an electron transporting light emitting layer. The film thickness referred to here is a value indicated by a crystal oscillation type film thickness monitor. Then 48
0 openings of 250 μm (remaining width 50 μm, 300 μm
The shadow mask provided with (equivalent to m pitches) was exchanged in a vacuum so as to be orthogonal to the ITO stripe, and was fixed with a magnet from the back surface so that the shadow mask and the ITO substrate were in close contact with each other. The thickness of the mask part of the shadow mask is 10
A mesh-like reinforcing line having a regular hexagonal structure having a width of 40 μm, a thickness of 35 μm, and a distance between two opposing sides of 200 μm is formed on the side of the mask portion opposite to the ITO substrate contact surface. The gap with the ITO substrate is 100 μm, which is the thickness of the mask portion. 5 magnesium as cathode
0 nm, 1 μm of aluminum is deposited and 640 × 480
A dot matrix device was manufactured. When this device was driven in a matrix, characters could be displayed at a luminance unevenness of 15%.

Example 2 Magnesium and aluminum for the cathode were also driven in a matrix exactly as in the example except that the vapor deposition was performed using two vapor deposition sources, and a luminance display of 11% was achieved.

Comparative Example 1 An element manufactured in exactly the same manner as in Example 1 except that evaporation was performed using one evaporation source at one location was driven. As a result, display unevenness was 32%.

[0042]

According to the present invention, it is possible to provide a method for manufacturing a light-emitting element capable of obtaining uniform light emission without thickness unevenness.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of film thickness non-uniformity due to one evaporation source.

FIG. 2 is a schematic diagram of film thickness uniformity by four evaporation sources at an equal evaporation rate.

FIG. 3 is a schematic diagram of film thickness uniformity by four evaporation sources having different evaporation rates.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Deposit 3 Deposition source

Claims (7)

[Claims] 1. A device which emits light by electric energy, wherein a substance responsible for light emission is present between a positive electrode and a negative electrode, the manufacturing process comprising a step of depositing the same material from two or more deposition sources. A method for manufacturing a light-emitting element. 2. The method according to claim 1, wherein said material is a substance which controls light emission. 3. The method according to claim 1, further comprising the step of using a shadow mask provided with reinforcing lines for pattern formation. 4. The method according to claim 1, wherein the evaporation sources are independently controlled. 5. The method according to claim 1, wherein the substrate on which the deposition material is deposited is moving. 6. The method according to claim 1, wherein the substrate on which the deposition material is deposited is rotating. 7. The method for manufacturing a light emitting device according to claim 1, wherein the light emitting device is a display for displaying in a matrix and / or a segment system.