JP2011227248A - Electrochromic display device and manufacturing method of electrochromic display device - Google Patents

Abstract

An electrochromic display device capable of developing an arbitrary color with simple control and improved in yield, and a method for manufacturing the electrochromic display device are provided.
A display substrate, a plurality of display electrodes 13 stacked separately from each other, a plurality of electrochromic layers stacked in contact with each of the plurality of display electrodes, a counter electrode, A counter substrate 12 and an electrolyte 20 provided so as to be sandwiched between the display electrode 13 and the counter electrode 15, and one of the plurality of display electrodes 13 and another display electrode 13 The electrical resistance between them is larger than the electrical resistance of the one display electrode, and the outer edges of the plurality of display electrodes 13 do not overlap each other.
[Selection] Figure 2

Description

  The present invention relates to an electrochromic display device and an electrochromic display device manufacturing method, and more particularly, to an electrochromic display device capable of multicolor display and an electrochromic display device manufacturing method.

In recent years, electronic paper has been actively developed as an electronic medium replacing paper.
Since electronic paper is characterized in that the display device is used like paper, characteristics different from those of conventional display devices such as CRT (cathode-ray tube) and liquid crystal display are required. For example, it is a reflection type display device, has a high white reflectance and a high contrast ratio, can display a high definition, has a memory effect in display, can be driven even at a low voltage, is thin and light, and is inexpensive It is necessary to have characteristics such as Among these, in particular, as characteristics relating to display quality, there is a high demand for white reflectance and contrast ratio equivalent to paper.

Until now, as a display device for electronic paper, for example, a method using a reflective liquid crystal, a method using electrophoresis, a method using toner migration, and the like have been proposed. However, it is very difficult for any of the above methods to perform multicolor display while ensuring white reflectance / contrast ratio. In general, in order to perform multicolor display, a color filter is provided. However, if a color filter is provided, the color filter itself absorbs light, and the reflectance decreases. Furthermore, since the color filter divides one pixel into red (R), green (G), and blue (B), the reflectance of the display device is lowered.
When the white reflectance / contrast ratio is significantly reduced, the visibility is very poor and it is difficult to use as electronic paper.

On the other hand, as a promising technique for realizing a reflective display device without providing the color filter as described above, there is a method using an electrochromic phenomenon.
A phenomenon in which a redox reaction occurs reversibly and a color changes reversibly by applying a voltage is called electrochromism. An electrochromic display device is a display device that utilizes the coloring / decoloring (hereinafter referred to as color erasing) of an electrochromic compound that causes this electrochromic phenomenon. Since this electrochromic display device is a reflective display device, has a memory effect, and can be driven at a low voltage, it is a leading candidate for display device technology for electronic paper use, from material development to device design. R & D has been conducted extensively.

  However, the electrochromic display device has a drawback in that the response speed of color development / decoloration is slow because of the principle of performing color development / decoloration using an oxidation-reduction reaction. Patent Document 1 describes an example in which an electrochromic compound is fixed in the vicinity of an electrode to improve the response speed of color development and decoloration. According to the description in Patent Document 1, the time required for color development and decoloration, which has been about several tens of seconds, has been improved to about 1 second for both the color development time from colorless to blue and the color erase time from blue to colorless. Yes. However, this is not sufficient, and in the research and development of electrochromic display devices, it is necessary to further improve the response speed of color development and decoloration.

On the other hand, the electrochromic display device is expected as a multicolor display device because various colors can be developed depending on the structure of the electrochromic compound.
There are some known examples of multicolor display devices using such electrochromic display devices.

For example, Patent Document 2 discloses a multicolor display device using an electrochromic compound in which fine particles of a plurality of types of electrochromic compounds are stacked. This Patent Document 2 describes an example of a multicolor display device in which a plurality of electrochromic compounds, which are polymer compounds having a plurality of functional functional groups with different voltages exhibiting color development, are laminated to form a multicolor display electrochromic compound. ing.
However, in the method disclosed in Patent Document 2, each of the laminated electrochromic compounds is a compound that develops a different color at a different voltage. Although possible, there was a problem that a plurality of colors could not be developed simultaneously. For this reason, a multicolor display device capable of simultaneously developing a plurality of colors is desired.

Therefore, Patent Document 3 discloses a display device in which a plurality of electrochromic layers are formed on an electrode, and multiple colors are developed using a difference in voltage value or current value necessary for the color development. In this patent document 3, a multicolor display device having a display layer formed by laminating or mixing a plurality of electrochromic compounds that develop different colors and have different threshold voltages for color development and different charge amounts necessary for color development. Examples are described.
However, since the method disclosed in Patent Document 3 has a plurality of types of electrochromic compounds that develop different colors, a plurality of colors can be developed simultaneously, but any color can be selectively developed. Therefore, there is a problem that complicated voltage / current control is required.

Here, in the patent document 4, the present inventors disclosed an electrochromic display device having a configuration in which a plurality of display electrodes and a corresponding plurality of electrochromic layers are stacked on a display substrate. This electrochromic display device was able to display a color capable of individually developing a plurality of colors by a simple method. The electrochromic display device of Patent Document 4 is an ideal reflective color display device that can display high whiteness and a wide color range.
However, the method disclosed in Patent Document 4 is a medium configuration in which a plurality of electrodes, electrochromic display layers, and the like are stacked, and defects such as film peeling may occur during manufacture. In particular, the outer edge portion of the display electrode is a portion where film peeling is likely to occur because a step corresponding to the thickness of the electrode occurs.

  The present invention has been made in view of the above points, and it is possible to develop an arbitrary color with simple control, eliminate defects such as film peeling of the electrochromic layer, and improve the yield. It is an object to provide a method for manufacturing a chromic display device and an electrochromic display device.

In order to solve the above problems, the electrochromic display device and the method for manufacturing the electrochromic display device according to the present invention specifically have the technical features described in the following (1) to (7).
(1): a display substrate, a plurality of display electrodes stacked separately from each other, a plurality of electrochromic layers stacked in contact with each of the plurality of display electrodes, a counter electrode, a counter substrate, An electrolyte provided so as to be sandwiched between the display electrode and the counter electrode, and an electrical resistance between one of the plurality of display electrodes and the other display electrode is The electrochromic display device is characterized in that it has an electrical resistance greater than that of the display electrodes and the outer edges of the plurality of display electrodes do not overlap each other.
With the configuration (1), it is possible to suppress the occurrence of film peeling at the outer edge portion of the display electrode, and it is possible to improve the yield of the electrochromic display device.

(2): In the plurality of display electrodes, when the first display electrode, the second display electrode,... The Nth display electrode are sequentially arranged from the display electrode closer to the display substrate, the nth display. The electrochromic display device according to (1), wherein the outer edge of the electrode is formed inside the outer edge of the (n-1) th display electrode.
However, N is an integer greater than or equal to 2, and n is an integer satisfying 2 ≦ n ≦ N.
With the configuration (2), it is possible to suppress the occurrence of film peeling at the outer edge portion of the display electrode, and it is possible to improve the yield of the electrochromic display device.

(3) The electrochromic display device according to (1) or (2), wherein the electrochromic layer includes an electrochromic compound and metal oxide particles.
With the configuration of (3) above, electrons (or holes) can be transmitted from the display electrode through the metal oxide to the electrochromic compound, and color can be more efficiently developed and decolored. In addition, the metal oxide particles can have a large specific surface area, and can carry out color development and decoloration with high contrast by supporting a large number of electrochromic compounds. This effect is significant with nanoparticles having a small particle size.

(4): The electro according to any one of (1) to (3), wherein an insulating layer for insulating the plurality of display electrodes from each other is provided between the plurality of display electrodes. It is a chromic display device.
With the configuration of (4) above, it is easy to make the electrical resistance between the display electrodes larger than the electrical resistance of the display electrodes. The contrast can be further improved.

(5): The display electrode is an inorganic material containing In oxide, Sn oxide, or Zn oxide formed by vacuum film formation. The electrochromic display device described in 1.
With the configuration (5), good transparency and electrical conductivity can be obtained by the In oxide, Sn oxide, and Zn oxide. Particularly preferred materials are InSnO, GaZnO, SnO, In ₂ O ₃ and ZnO.

(6): a first display electrode forming step of forming the first display electrode on the display substrate by vacuum film formation; and the first display electrode is formed on the display substrate on which the first display electrode is formed. A first electrochromic layer forming step for forming a corresponding first electrochromic layer, and an outer edge of the first display electrode is not overlapped by vacuum film formation on the display substrate on which the first electrochromic layer is formed. And a second display electrode forming step for forming a second display electrode, and a second electrochromic layer corresponding to the second display electrode is formed on the display substrate on which the second display electrode is formed. A second electrochromic layer forming step, a counter substrate on which a counter electrode is formed, the first display electrode, the first electrochromic layer, the second display electrode, and the second electrochromic layer; And a bonding step of bonding the formed display substrate with an electrolyte sandwiched so that the counter electrode and the second electrochromic layer face each other. It is.
With the configuration (6), an electrochromic display device capable of developing multiple colors can be manufactured with high yield.

(7): a first display electrode forming step of forming the first display electrode on the display substrate by vacuum film formation; and the first display electrode is formed on the display substrate on which the first display electrode is formed. A first electrochromic layer forming step of forming a corresponding first electrochromic layer, and a vacuum deposition on the display substrate on which the first electrochromic layer has been formed, inside the outer edge of the first display electrode. A second display electrode forming step for forming a second display electrode, and a second electrochromic layer corresponding to the second display electrode on the display substrate on which the second display electrode is formed. An electrochromic layer forming step, a third display electrode forming step of forming a third display electrode inside an outer edge of the first display electrode and the second display electrode by vacuum film formation, and the third display electrode Display electrode A third electrochromic layer forming step of forming a third electrochromic layer corresponding to the third display electrode on the formed display substrate; a counter substrate on which a counter electrode is formed; and the first display electrode. A display substrate on which the first electrochromic layer, the second display electrode, the second electrochromic layer, the third display electrode, and the third electrochromic layer are formed, and the counter electrode. And a bonding step in which the electrolyte is sandwiched and bonded so that the third electrochromic layer faces each other. The method of manufacturing an electrochromic display device.
With the configuration (7), an electrochromic display device capable of generating multiple colors can be manufactured with high yield.

  According to the present invention, it is possible to provide an electrochromic display device and an electrochromic display device manufacturing method capable of developing any color with simple control and improving the yield.

It is sectional drawing which shows typically the structure in one Embodiment of the electrochromic display apparatus which concerns on this invention. It is a top view which shows typically the structure of the display electrode in each embodiment of the electrochromic display apparatus which concerns on this invention. It is a top view which shows typically the structure of the display electrode in other embodiment of the electrochromic display apparatus which concerns on this invention. 3 is a top view schematically showing the configuration of display electrodes in the electrochromic display device of Example 1. FIG. 6 is a top view schematically showing a configuration of display electrodes in an electrochromic display device of Comparative Example 1. FIG. 6 is a top view schematically showing a configuration of display electrodes in an electrochromic display device of Example 2. FIG.

Next, a mode for carrying out the present invention will be described with reference to the drawings.
The electrochromic display device of the present invention will be described with reference to FIG. However, FIG. 1 shows an example of the electrochromic display device of the present invention, and the electrochromic display device of the present invention is not limited to the configuration of FIG.

First, the configuration of the electrochromic display device 10 will be described.
As shown in FIG. 1, an electrochromic display device 10 according to a first embodiment of the present invention includes a display substrate 11, a counter substrate 12 provided to face the display substrate 11, a display substrate 11, A cell 19 is attached to the counter substrate 12 via a spacer 18.
The display substrate 11 is in contact with the first display electrode 13a formed on the display substrate 11, the first electrochromic layer 14a provided in contact with the first display electrode 13a, and the first electrochromic layer 14a. An insulating layer 22 provided in contact with the insulating layer 22, a second display electrode 13b provided in contact with the insulating layer 22, and a second electrochromic layer 14b provided in contact with the second display electrode 13b. The display substrate 11 is a substrate for supporting the above laminated structure.

  The first display electrode 13a is an electrode for controlling the potential with respect to the counter electrode 15 and causing the first electrochromic layer 14a to develop color.

  The first electrochromic layer 14a includes a first electrochromic compound 16a and a metal oxide 17 that supports the first electrochromic compound 16a. The first electrochromic compound 16a is a portion that develops color by an oxidation-reduction reaction, and the metal oxide 17 is for carrying the first electrochromic compound 16a and performing color development and decoloration at high speed. In FIG. 1, a configuration in which a single molecule of the electrochromic compound 16a is adsorbed on the metal oxide 17 is described as an ideal model. However, the metal oxide 17 and the electrochromic compound 16a may act, and the mixed layer and It may be. Specific embodiments and actions of the metal oxide 17 will be described later.

  The insulating layer 22 is isolated so that the first display electrode 13a provided with the first electrochromic layer 14a and the second display electrode 13b provided with the second electrochromic layer 14b are insulated. Is to do. The first display electrode 13a and the second display electrode 13b must be formed such that the electrical resistance between the display electrodes is larger than the electrical resistance of the display electrodes in order to independently control the potential with respect to the counter electrode 15. It is preferable that the resistance between at least the display electrodes is at least 500 times the display electrode resistance. The insulation between the display electrodes can be controlled by the thickness of the electrochromic layer 14a, but it is preferable to control by forming the insulating layer 22.

  Similar to the first display electrode 13a, the second display electrode 13b is an electrode for controlling the potential with respect to the counter electrode 15 and causing the second electrochromic layer 14b to develop color.

  Similarly to the first electrochromic layer 14a, the second electrochromic layer 14b includes a second electrochromic compound 16b and a metal oxide 17 that supports the second electrochromic compound 16b. Similarly to the first electrochromic compound 16a, the second electrochromic compound 16b is a portion that develops a color by an oxidation-reduction reaction, and the metal oxide 17 carries the second electrochromic compound 16b and emits light. It is for performing color at high speed. The second electrochromic compound 16b develops a color different from that of the first electrochromic compound 16a.

  The counter substrate 12 has a counter electrode 15 formed on the counter substrate 12. The counter electrode 15 is an electrode for controlling the potential of the first display electrode 13a or the second display electrode 13b with respect to the counter electrode 15 and causing the first electrochromic layer 14a or the second electrochromic layer 14b to develop a color. The counter substrate 12 is for supporting the counter electrode 15.

  The cell 19 has a structure in which the display substrate 11 and the counter substrate 12 are bonded to each other through a spacer 18. The cell 19 is filled with an electrolyte 20. The electrolyte 20 moves charges as ions between the first display electrode 13a or the second display electrode 13b and the counter electrode 15, and develops the color of the first electrochromic layer 14a or the second electrochromic layer 14b. It is for waking up. The electrolyte can be held in a polymer, and a color-decoloring region (that is, a pixel) can be easily formed by patterning the polymer.

  A white reflective layer 21 is provided in the cell 19. The white reflective layer 21 is for improving the white reflectance when the electrochromic display device 10 is used as a reflective display device. The white reflective layer 21 is formed by injecting the electrolyte 20 in which white pigment particles are dispersed into the cell 19. Alternatively, the white reflective layer 21 may be formed by applying a resin in which white pigment particles are dispersed on the counter electrode 15.

  Furthermore, by forming an organic protective layer (not shown) made of an organic polymer material in contact with the first electrochromic layer 14a and / or the second electrochromic layer 14b, the adhesion of the electrochromic layer, Solvent resistance can be improved, and durability can be enhanced.

  In addition, by forming an inorganic protective layer (not shown) between the second electrochromic layer 14b and the electrolytic solution 20, damage due to the electrolytic solution can be reduced and durability can be improved.

In the present invention, in the electrochromic display device 10 configured as described above, the outer edge of the first display electrode 13a and the outer edge of the second display electrode 13b do not overlap each other. FIG. 2A, FIG. 2B, and FIG. 2C show configuration examples.
The electrochromic display device of the present invention is characterized in that the outer edges of the display electrodes 13 do not overlap each other as shown in any of FIGS. With this medium configuration, the distortion due to the film thickness difference at the boundary portion of the display electrode 13 is not concentrated on one outer edge portion but is dispersed in a plurality of locations, and the probability that the electrochromic layer 14 is peeled off is greatly increased. Diminished. A portion for displaying an image or the like is a range surrounded by each display electrode 13. What is necessary is just to conceal except a display part by providing a shielding layer on the display substrate 11, for example.

Here, the outer edge is a line connecting the end portions of the display electrode 13, and in the example shown in FIGS. 2A to 2C, a thick line (first display electrode 13a) and a broken line are formed inside the display substrate 11. (Second display electrode 13b), represented by a straight line (normal thickness; third display electrode 13c). Further, as will be described later, an electrode extraction portion of the display electrode 13 can also be handled as the outer edge of the display electrode 13 in the present invention.
In the present invention, the fact that the outer edges of the plurality of display electrodes 13 do not overlap each other means that the outer edge of one display electrode intersects with the outer edge of the other one display electrode only by two points. That is, when the N display electrodes are arranged on the display substrate, the outer edges of the M display electrodes do not intersect each other except for the intersection of N × (N−1). (However, N is an integer of 2 or more.)

Another feature of the present invention is that when the first display electrode 13a, the second display electrode 13b, the third display electrode 13c,. The outer edge of the display electrode 13b is formed inside the outer edge of the first display electrode 13a, and the outer edge of the third display electrode 13c is formed inside the outer edge of the second display electrode 13b. It is to become.
In other words, when the first display electrode 13a, the second display electrode 13b,... The nth display electrode 13n are sequentially formed from the display electrode 13 on the side closer to the display substrate 11, the nth display electrode 13n The outer edge is formed inside the outer edge of the (n-1) th display electrode 13n-1. (However, N is an integer of 2 or more, and n is an integer satisfying 2 ≦ n ≦ N.)
FIG. 3 shows a configuration example, and details will be described below.

  The display substrate 1 side of the electrochromic display device of the present invention has a first display electrode 13a, a first electrochromic layer 14a, a second display electrode 13b, and a second electrochromic layer 14b with respect to the display substrate 1. The third display electrode 13c and the third electrochromic layer 14c are stacked in this order. That is, since the display electrode to be formed later is formed inside the outer edge of the display electrode that has been previously formed, the next display electrode can be formed without being affected by the step due to the display electrode that has been formed previously, It is possible to prevent the display electrode from being cut due to the step. The part where the image or the like is actually displayed uses the inside of the display electrode formed last. This portion is a portion where all the display electrodes and the display layer are uniformly formed, and high quality display can be performed.

  As shown in the configuration example of FIG. 3, the display electrode 13 needs to be provided with an electrode extraction portion. In order to take out each electrode from the plurality of stacked display electrodes 13, only the take-out portions may overlap as in the configuration example of FIG.

Next, the multicolor display operation of the electrochromic display device 10 of the present invention will be described.
The electrochromic display device 10 can easily perform multicolor display by having the above-described structure. That is, since the first display electrode 13a and the second display electrode 13b are provided separately via the insulating layer 22, the potential of the first display electrode 13a with respect to the counter electrode 15 and the counter electrode 15, and the potential of the second display electrode 13 b with respect to 15 can be controlled independently. As a result, the first electrochromic layer 14a provided in contact with the first display electrode 13a and the second electrochromic layer 14b provided in contact with the second display electrode 13b are independently generated. Can be decolored. Further, even if not completely insulated, by setting the electric resistance between the display electrodes to be larger than the electric resistance of the display electrodes, the redox potential difference between the electrochromic layer 14a and the electrochromic layer 14b is used, and Independent control is possible by applying a voltage that does not cause color generation / decoloration other than the display electrodes that cause color development.

  Since the first electrochromic layer 14a and the second electrochromic layer 14b are stacked on the display substrate 11 side, the first electrochromic layer 14a and the second electrochromic layer 14b are generated. According to the decoloring pattern, color development of only the first electrochromic layer 14a, color development of only the second electrochromic layer 14b, color development of both the first electrochromic layer 14a and the second electrochromic layer 14b, 3 The color can be changed to a step color, and multicolor display is possible.

  For example, as the first electrochromic layer 14a or the second electrochromic layer 14b, two types of electrochromic layers that develop two different colors of red, green, blue, and the like are used, so that multicolor display can be achieved. Is possible.

Further, since the white reflective layer 21 is provided in the cell 19, the white reflectance is high, and the reflectance is reduced due to the stacked first electrochromic layer 14a and second electrochromic layer 14b. This can be supplemented and multi-color display with excellent visibility is possible.
Further, the first electrochromic layer 14a and the second electrochromic layer 14b have a structure in which the first electrochromic compound 16a and the second electrochromic compound 16b are supported on the metal oxide 17, respectively. Multicolor display with excellent color response speed is possible. In particular, when an organic compound material having a low electron (or hole) mobility is used for the first electrochromic compound 16a or the second electrochromic compound 16b, the first display electrode 13a or the second display electrode. From 13b, electrons (or holes) do not conduct inside the first electrochromic compound 16a or the second electrochromic compound 16b, but from the first electrochromic compound 16a or the second electrochromic compound 16b. Since electrons (or holes) can be conducted through the metal oxide 17 having a high electron (or hole) mobility, color development and decoloration can be performed at a higher speed, and the response speed of color development and decoloration can be improved. Excellent multicolor display is possible.

Next, materials used for the electrochromic display device 10 of the present invention will be described.
First, the material of each layer formed on the display substrate 11 and the display substrate 11 will be described.
The material of the display substrate 11 is not particularly limited as long as it is a transparent material, but a substrate such as a glass substrate or a plastic film is used.

The material of the first display electrode 13a and the second display electrode 13b is not particularly limited as long as it is a conductive material. However, since it is necessary to ensure light transmission, it is a transparent material. A transparent electrode made of is used. The material for the transparent electrode is not particularly limited, but includes tin-doped indium oxide (hereinafter ITO), fluorine-doped tin oxide (hereinafter FTO), antimony-doped tin oxide (hereinafter ATO), and the like. Used.
In particular, at least one of the display electrodes is preferably an inorganic material including any one of In oxide, Sn oxide, and Zn oxide formed by vacuum film formation. The In oxide, Sn oxide, and Zn oxide can provide good transparency and electrical conductivity, and can be easily formed by sputtering. Particularly preferred materials are InSnO, GaZnO, SnO, In ₂ O ₃ and ZnO.

  As the material of the first electrochromic compound 16a or the second electrochromic compound 16b included in the first electrochromic layer 14a or the second electrochromic layer 14b, a material that causes a color change by oxidation-reduction is used. . As such a material, a known electrochromic compound such as a polymer, a dye, a metal complex, or a metal oxide is used.

  Specifically, polymer-based and dye-based electrochromic compounds include azobenzene, anthraquinone, diarylethene, dihydroprene, styryl, styryl spiropyran, spirooxazine, spirothiopyran, thioindigo, tetrathiafulvalene , Terephthalic acid, triphenylmethane, triphenylamine, naphthopyran, viologen, pyrazoline, phenazine, phenylenediamine, phenoxazine, phenothiazine, phthalocyanine, fluoran, fulgide, benzopyran, Low molecular organic electrochromic compounds such as metallocenes, and conductive polymer compounds such as polyaniline and polythiophene are used.

In particular, a viologen compound or a terephthalic acid compound is preferably included. These materials have a low color development / discoloration potential and exhibit good color values even in a plurality of display electrode configurations.
Of these materials, examples of the viologen type are described in Japanese Patent No. 39555641, Japanese Patent Application Laid-Open No. 2007-171781, and examples of the terephthalic acid type are described in Japanese Patent Application Laid-Open No. 2006-71767.

  Furthermore, the electrochromic compounds provided on the plurality of display electrodes are preferably all viologen-based or all terephthalic acid-based. By adopting a similar material structure, the color development / erasure potential of each display electrode can be made uniform, and the color development / erasure can be easily controlled with the same electrolyte.

  On the other hand, inorganic electrochromic compounds such as titanium oxide, vanadium oxide, tungsten oxide, indium oxide, iridium oxide, nickel oxide, and Prussian blue are used as the metal complex-based and metal oxide-based electrochromic compounds.

  The material of the metal oxide 17 is not particularly limited, but titanium oxide, zinc oxide, tin oxide, aluminum oxide (hereinafter referred to as alumina), zirconium oxide, cerium oxide, silicon oxide (hereinafter referred to as silica), yttrium oxide, Oxygen boron, magnesium oxide, strontium titanate, potassium titanate, barium titanate, calcium titanate, calcium oxide, ferrite, hafnium oxide, tungsten oxide, iron oxide, copper oxide, nickel oxide, cobalt oxide, barium oxide, strontium oxide Metal oxides mainly composed of vanadium oxide, aluminosilicate, calcium phosphate, aluminosilicate and the like are used. Moreover, these metal oxides may be used independently and 2 or more types may be mixed and used. In view of electrical properties such as electrical conductivity and physical properties such as optical properties, it is selected from titanium oxide, zinc oxide, tin oxide, alumina, zirconium oxide, iron oxide, magnesium oxide, indium oxide, and tungsten oxide. When one kind or a mixture thereof is used, multicolor display excellent in response speed of color development and decoloration is possible. In particular, when titanium oxide is used, multicolor display with a more excellent response speed of color development and decoloration is possible.

  Further, the shape of the metal oxide 17 is not particularly limited, but in order to efficiently support the first electrochromic compound 16a or the second electrochromic compound 16b, the surface area per unit volume (hereinafter referred to as the ratio). A shape having a large surface area is used. For example, when the metal oxide 17 is an aggregate of nanoparticles, since it has a large specific surface area, the electrochromic compound is more efficiently supported, and a multicolor display excellent in display / decolor display contrast ratio is achieved. Is possible. As a method of supporting the electrochromic compound, it is necessary to use a mixed layer of the electrochromic compound and the metal oxide, but as a more efficient form, the electrochromic compound is bonded to the metal oxide by an adsorbing group. Is preferred.

The material of the insulating layer 22 is not particularly limited as long as it is porous. However, a material having high insulating properties, high durability, and excellent film forming properties is preferable. Particularly preferred is a material containing at least ZnS. ZnS can be formed at high speed by sputtering and can be formed without damaging the electrochromic layer. Examples of the film containing ZnS as a main component include ZnS—SiO ₂ , ZnS—SiC, ZnS—Si, ZnS—Ge, and the like. The ZnS ratio is preferably about 50 to 90 mol% from the viewpoint of crystallinity. Particularly preferred materials are ZnS—SiO ₂ (8/2), ZnS—SiO ₂ (7/3), ZnS, ZnS—ZnO—In ₂ O ₃ —Ga ₂ O ₃ (60/23/10/7). .
The porous film can be easily obtained by forming it as a particle film.
In particular, when ZnS or the like is formed by sputtering, the porous property can be imparted by previously forming a particle film as an undercoat layer.

This particle film can also serve as the above-described metal oxide 17, but a porous particle film containing silica, alumina or the like may be formed separately.
The porous insulating layer allows the electrolyte 20 to permeate through the insulating layer 22. Therefore, the charge transfer as ions in the electrolyte 20 accompanying the oxidation-reduction reaction is facilitated, and the response speed of color development and decoloration is excellent. Multicolor display is possible.

The film thickness of the inorganic insulating layer is in the range of 20 nm to 500 nm, preferably 50 to 150 nm.
This is because if the film thickness is thin from this range, it is difficult to obtain insulation, and if it is thick, the cost is increased and the visibility is liable to decrease due to coloring.

Next, the material of the counter substrate 12 and the counter electrode 15 formed on the counter substrate 12 will be described.
The material of the counter substrate 12 is not particularly limited, and the material of the counter electrode 15 is not particularly limited as long as it is a conductive material. When a glass substrate or a plastic film is used as the counter substrate 12, the counter electrode 15 may be made of a transparent conductive film such as ITO, FTO, or zinc oxide, or a conductive metal film such as zinc or platinum, or carbon. Used. The counter electrode 15 made of these transparent conductive film or conductive metal is used by being coated on the counter substrate 12. On the other hand, when a metal plate such as zinc is used as the counter electrode 15, the counter electrode 15 also serves as the counter substrate 12.

  Further, when the material of the counter electrode 15 is a material that causes a reverse reaction opposite to the redox reaction caused by the first electrochromic layer 14a or the second electrochromic layer 14b, stable color development and decoloration is possible. . That is, when the first electrochromic layer 14a or the second electrochromic layer 14b is colored by oxidation, a reduction reaction occurs, and the first electrochromic layer 14a or the second electrochromic layer 14b is colored by reduction. When a material that causes an oxidation reaction is used as the counter electrode 15, the reaction of color development and decoloration in the first electrochromic layer 14a or the second electrochromic layer 14b becomes more stable.

Next, the materials of the electrolyte 20 and the white reflective layer 21 constituting the cell 19 will be described.
As a material for the electrolyte 20, generally, a material in which a supporting salt is dissolved in a solvent is used. As the supporting salt, for example, inorganic ion salts such as alkali metal salts and alkaline earth metal salts, quaternary ammonium salts, acids, and alkali supporting salts can be used. Specifically, LiClO ₄ , LiBF ₄ , LiAsF ₆ , LiPF ₆ , LiCF ₃ SO ₃ , LiCF ₃ COO, KCl, NaClO ₃ , NaCl, NaBF ₄ , NaSCN, KBF ₄ , Mg (ClO ₄ ) ₂ , Mg (BF ₄ ) ₂ etc. can be used. Examples of the solvent include propylene carbonate, acetonitrile, γ-butyrolactone, ethylene carbonate, sulfolane, dioxolane, tetrahydrofuran, 2-methyltetrahydrofuran, dimethyl sulfoxide, 1,2-dimethoxyethane, 1,2-ethoxymethoxyethane, and polyethylene glycol. , Alcohols are used. In addition, since it is not particularly limited to a liquid electrolyte in which a supporting salt is dissolved in a solvent, a gel electrolyte or a solid electrolyte such as a polymer electrolyte is also used.

  In particular, in the present invention in which a plurality of display electrodes and an electrochromic layer are formed, patterning each layer in accordance with the shape of the matrix electrode increases the cost. Therefore, it is preferable to pattern the polymer electrolyte. Specifically, the electrolyte and the solvent are mixed with a white or transparent ink and patterned by an ink jet method or a screen printing method. The ink may be a general UV effect ink or thermal effect ink, but preferably has a low density structure with a low crosslinking rate in order to retain the electrolyte and solvent.

Furthermore, it can also serve as a white reflective layer by mixing white pigment particles in the polymer electrolyte.
Examples of the material of the white pigment particles contained in the white reflective layer 21 include titanium oxide, aluminum oxide, zinc oxide, silica, cesium oxide, yttrium oxide, and the like.

  As described above, according to the electrochromic display device 10 according to the present embodiment, the potential of the first display electrode 13a and the potential of the second display electrode 13b are independently controlled, and the first electrochromic layer is controlled. Since 14a and the second electrochromic layer 14b can be independently developed and decolored, an electrochromic display device capable of developing an arbitrary color with simple control can be provided.

  Furthermore, as an organic protective layer material made of an organic polymer material formed in contact with the first electrochromic layer 14a and / or the second electrochromic layer 14b, polyvinyl alcohol, poly N vinylamide, polyester, polystyrene, polypropylene, etc. A general resin can be selected from the adhesion with the material of the electrochromic layer 14a.

(Production method)
A method for manufacturing the electrochromic display device according to the first embodiment of the present invention will be described.
In the method of manufacturing the electrochromic display device of the present invention, at least the first electrochromic layer 14a is formed by spin coating or screen printing on the display substrate 11 on which the first display electrode 13a is formed, and at least the first electrochromic layer 14a is further formed thereon. The second display electrode 13b is formed by vacuum film formation, and at least the second electrochromic layer 14b is formed thereon by spin coating or screen printing. The counter substrate 12 on which the counter electrode 15 is formed and the electrodes face each other. Thus, it can manufacture easily by sticking together electrolyte 20 in between.

That is, the manufacturing method of the electrochromic display device according to the first embodiment of the present invention includes the following steps (a) to (d).
(A) A step of providing the first electrochromic layer 14a by spin coating or screen printing on the display substrate 11 on which the first display electrode 13a is formed.
(B) A step of providing the inorganic insulating layer 22 and the second display electrode 13b on the first electrochromic layer 14a by vacuum film formation.
(C) A step of providing the second electrochromic layer 14b on the second display electrode 13b by spin coating or screen printing.
(D) A step of bonding the display substrate 11 and the counter substrate 12 on which the counter electrode 15 is formed, via an electrolytic solution 20 containing particles for the white reflective layer 21.

(Electrochromic layer formation process)
In the method for manufacturing an electrochromic display device of the present invention, first, a first electrochromic layer 14a composed of an electrochromic compound 16a and metal oxide particles 17 is formed on a display substrate 11 on which a first display electrode 13a is formed. Provided by film means or screen printing means. That is, the electrochromic layer 14a is formed by dispersing or dissolving the metal oxide particles 17 and the electrochromic compound 14a in a solvent and coating the substrate as a liquid coating ink. Alternatively, the coating ink is formed by screen printing.

  As a solvent for adjusting the coating ink, a known solvent (for example, water, alcohol, cellosolve, halogenated carbon, ketone, ether, etc.) can be used.

  The electrochromic layer 14a composed of the electrochromic compound 16a and the metal oxide particles 17 is preferably applied as a coating ink in which the electrochromic compound 16a and the metal oxide particles 17 are mixed, but the metal oxide particle 17 dispersion is coated. Thereafter, the electrochromic compound 16a can be coated thereon.

(Process for providing inorganic insulating layer and display electrode)
In the method for manufacturing an electrochromic display device of the present invention, the inorganic insulating layer 22 and the second display electrode 13b are then provided on the electrochromic layer 14a by vacuum film forming means. That is, the inorganic insulating layer 22 and the second display electrode 13b are formed on the first electrochromic layer 14a by, for example, vapor deposition, sputtering or ion plating of the inorganic material described above.

(Lamination process)
In the method for manufacturing the electrochromic display device of the present invention, the display substrate 11 on which the second electrochromic layer 14b is further formed on the inorganic insulating layer 22 and the second display electrode 13b, and the counter electrode 15 is formed on the opposite side. The substrate 12 is bonded to the substrate 12 via the electrolytic solution 20 containing the particles for the white reflective layer 21. That is, the display substrate 11 and the counter substrate 12 are bonded together via the spacer 18, and the electrolytic solution 20 containing the particles for the white reflective layer 21 is vacuum-injected into the space, and then the injection port is sealed. Alternatively, the white reflective layer 21 may be formed by applying a resin in which white pigment particles are dispersed on the counter electrode 15.

  Alternatively, a polymer electrolyte UV ink is prepared, applied to the display substrate 11 or the counter substrate 15 by patterning by screen printing or an ink jet method, and then the corresponding substrate is covered from above and the electrolyte 20 is infiltrated, and then cured by ultraviolet irradiation. Let

[Example 1]
(Preparation of display electrode and electrochromic layer)
An ITO film of about 100 nm was formed on a 40 mm × 40 mm glass substrate by a sputtering method in a 30 mm × 25 mm region, and a first display electrode was produced. The resistance between the electrode ends was about 200Ω. A titanium oxide nanoparticle dispersion (SP210 Showa Titanium) was spin-coated on this, and a titanium oxide particle film was formed by annealing at 120 ° C. for 15 minutes. Further, 5 wt% of the following viologen compound (A) 2% A 2,3,3 tetrafluoropropanol solution was spin-coated, and a first electrochromic layer composed of titanium oxide particles and an electrochromic compound was formed by annealing at 120 ° C. for 10 minutes. Next, a protective layer is formed on this by spin-coating a 0.1 wt% poly N vinylamide ethanol solution and a 0.5 wt% polyvinyl alcohol aqueous solution, and an inorganic insulating layer of ZnS—SiO ₂ (8/2) is sputtered. To form a film thickness of 25 nm to 150 nm. Further, an ITO film having a thickness of about 100 nm was formed on this in a region of 25 mm × 25 mm so as not to overlap with the previously formed ITO film (first display electrode), thereby producing a second display electrode. The resistance between the electrode ends was 40Ω or more, and the resistance of the display electrode was about 200Ω.

  A titanium oxide nanoparticle dispersion (SP210 Showa Titanium) was spin-coated thereon, and a titanium oxide particle film was formed by annealing at 120 ° C. for 15 minutes. Further, 1 wt% 2 of the following viologen compound (B): A display substrate of the present invention is formed by spin-coating a 2,3,3 tetrafluoropropanol solution and forming a second electrochromic layer composed of titanium oxide particles and an electrochromic compound by annealing at 120 ° C. for 10 minutes. Obtained. FIG. 4 shows the positional relationship between the two display electrodes.

(Preparation of counter electrode)
A counter electrode made of tin oxide was formed on the entire surface of a 40 mm × 40 mm glass substrate. On the upper surface of the glass substrate on which the transparent conductive thin film of tin oxide was formed on the entire surface, a solution obtained by adding 25 wt% of 2-ethoxyethyl acetate to thermosetting conductive carbon ink (CH-10 Jujo Chemical) was spin-coated. Thereafter, the counter electrode was fabricated by annealing at 120 ° C. for 15 minutes.

(Production of electrochromic display device)
The display substrate and the counter substrate were bonded to each other through a 75 μm spacer to manufacture a cell. Next, 35 wt% of titanium oxide particles (manufactured by Ishihara Sangyo Co., Ltd.) with a primary particle size of 300 nm are dispersed in a solution of 0.1 M perchloric acid chloride in propylene carbonate to prepare an electrolyte solution and enclosed in the cell Thus, an electrochromic display device was produced.
When the production was repeated 10 times by the same method, all the electrochromic display devices could be produced without any defects.

(Color development test)
A voltage was applied to the electrochromic display device produced in Example 1 to evaluate color development.
The applied voltage was 1.7 V and 2 seconds. The display electrode was connected to the negative electrode, and the counter electrode was connected to the positive electrode.
All the elements of Example 1 were able to independently color blue of the first display electrode and green of the second display electrode.

[Comparative Example 1]
A comparative electrochromic device was fabricated in the same manner as in Example 1 except that an ITO film was formed in a 30 mm × 25 mm region so that the second display electrode overlapped with the first display electrode. FIG. 5 shows the positional relationship between the two display electrodes.
When the fabrication was repeated 10 times by the same method, film peeling was observed between the second display electrode and the second electrochromic layer in three of the fabricated devices. All were along the outer edge portion of the display electrode.

(Color development test)
A voltage was applied to the electrochromic display device produced in Comparative Example 1 where no film peeling was observed, and color development was evaluated. The applied voltage was 1.7 V and 2 seconds. The display electrode was connected to the negative electrode, and the counter electrode was connected to the positive electrode.
Among the devices of Comparative Example 1, the device in which film peeling was not observed was able to independently color blue of the first display electrode and green of the second display electrode.

[Example 2]
An ITO film having a thickness of about 100 nm was formed on a 40 mm × 40 mm glass substrate by a sputtering method in a 30 mm × 30 mm region, and a first display electrode was produced. The resistance between the electrode ends was about 200Ω. A titanium oxide nanoparticle dispersion (SP210 Showa Titanium) was spin-coated thereon, and a titanium oxide particle film was formed by annealing at 120 ° C. for 15 minutes. Further, 5 wt% of the viologen compound (A) 2% A 2,3,3 tetrafluoropropanol solution was spin-coated, and a first electrochromic layer composed of titanium oxide particles and an electrochromic compound was formed by annealing at 120 ° C. for 10 minutes. Next, a protective layer is formed on this by spin-coating a 0.1 wt% poly N vinylamide ethanol solution and a 0.5 wt% polyvinyl alcohol aqueous solution, and an inorganic insulating layer of ZnS—SiO ₂ (8/2) is sputtered. To form a film thickness of 25 nm to 150 nm. Further, an ITO film with a thickness of about 100 nm was formed on the inner side of the previously formed ITO film (first display electrode) in a 25 mm × 25 mm region by sputtering to produce a second display electrode. The resistance between the electrode ends was 40Ω or more, and the resistance of the display electrode was about 200Ω.

A titanium oxide nanoparticle dispersion (SP210 Showa Titanium) was spin-coated on this, and a titanium oxide particle film was formed by annealing at 120 ° C. for 15 minutes. Further, 1 wt% 2 of the viologen compound (B) A 2,3,3 tetrafluoropropanol solution was spin-coated, and a second electrochromic layer composed of titanium oxide particles and an electrochromic compound was formed by annealing at 120 ° C. for 10 minutes. Next, a protective layer is formed on this by spin-coating a 0.1 wt% poly N vinylamide ethanol solution and a 0.5 wt% polyvinyl alcohol aqueous solution, and an inorganic insulating layer of ZnS—SiO ₂ (8/2) is sputtered. Was formed with a film thickness of 140 nm. Further, an ITO film having a thickness of about 100 nm was formed on the inner side of the second display electrode in a 20 mm × 15 mm region by sputtering to produce a third display electrode. The resistance between the electrode ends was 40Ω or more, and the resistance of the display electrode was about 200Ω. A titanium oxide nanoparticle dispersion (SP210 Showa Titanium) was spin-coated on this, and a titanium oxide particle film was formed by annealing at 120 ° C. for 15 minutes. Further, 1.0 wt% of the following viologen compound (C) was further formed thereon. By spin-coating a 2,2,3,3 tetrafluoropropanol solution as a coating solution and forming a third electrochromic layer composed of titanium oxide particles and an electrochromic compound by annealing at 120 ° C. for 10 minutes, An inventive display substrate was obtained. FIG. 6 shows the positional relationship between the three display electrodes.

(Preparation of counter electrode)
A counter electrode made of tin oxide was formed on the entire surface of a 40 mm × 40 mm glass substrate. On the upper surface of the glass substrate on which the transparent conductive thin film of tin oxide was formed on the entire surface, a solution obtained by adding 25 wt% of 2-ethoxyethyl acetate to thermosetting conductive carbon ink (CH-10 Jujo Chemical) was spin-coated. Thereafter, the counter electrode was fabricated by annealing at 120 ° C. for 15 minutes.

(Production of electrochromic display device)
The display substrate and the counter substrate were bonded to each other through a 75 μm spacer to manufacture a cell. Next, 35 wt% of titanium oxide particles (manufactured by Ishihara Sangyo Co., Ltd.) with a primary particle size of 300 nm are dispersed in a solution of 0.1 M perchloric acid chloride in propylene carbonate to prepare an electrolyte solution and enclosed in the cell Thus, an electrochromic display device was produced.
When the production was repeated 10 times by the same method, all the electrochromic display devices could be produced without any defects.

(Color development test)
A voltage was applied to the electrochromic display device produced in Example 2 to evaluate color development.
The applied voltage was 1.7 V and 2 seconds. The display electrode was connected to the negative electrode, and the counter electrode was connected to the positive electrode.
All of the elements of Example 2 were capable of independently coloring blue of the first display electrode, green of the second display electrode, and magenta of the third display electrode.

10 electrochromic display device 11 display substrate 12 counter substrate 13a first display electrode 13b second display electrode 13c third display electrode 14a first electrochromic layer 14b second electrochromic layer 15 counter electrode 16a first Electrochromic compound 16b Second electrochromic compound 17 Metal oxide 18 Spacer 19 Cell 20 Electrolyte 21 White reflective layer 22 Insulating layer

Special table 2001-510590 gazette JP 2003-121883 A JP 2006-106669 A JP 2010-33016 A

Claims (7)

A display substrate, a plurality of display electrodes stacked separately from each other, a plurality of electrochromic layers stacked in contact with each of the plurality of display electrodes, a counter electrode, a counter substrate, and the display electrode An electrolyte provided so as to be sandwiched between the counter electrode,
An electrical resistance between one of the plurality of display electrodes and another display electrode is larger than an electrical resistance of the one display electrode;
An electrochromic display device, wherein outer edges of the plurality of display electrodes do not overlap each other. In the plurality of display electrodes, when the first display electrode, the second display electrode,... The Nth display electrode are sequentially arranged from the display electrode closer to the display substrate, the outer edge of the nth display electrode is 2. The electrochromic display device according to claim 1, wherein the electrochromic display device is formed inside an outer edge of the (n-1) th display electrode.
However, N is an integer greater than or equal to 2, and n is an integer satisfying 2 ≦ n ≦ N.   The electrochromic display device according to claim 1, wherein the electrochromic layer includes an electrochromic compound and metal oxide particles.   4. The electrochromic display device according to claim 1, wherein an insulating layer for insulating the plurality of display electrodes from each other is provided between the plurality of display electrodes. 5.   5. The electrochromic display device according to claim 1, wherein the display electrode is an inorganic material containing In oxide, Sn oxide, or Zn oxide formed by vacuum film formation. 6. . A first display electrode forming step of forming a first display electrode on the display substrate by vacuum film formation;
A first electrochromic layer forming step of forming a first electrochromic layer corresponding to the first display electrode on the display substrate on which the first display electrode is formed;
A second display electrode forming step of forming a second display electrode on the display substrate on which the first electrochromic layer has been formed without overlapping an outer edge of the first display electrode by vacuum film formation;
A second electrochromic layer forming step of forming a second electrochromic layer corresponding to the second display electrode on the display substrate on which the second display electrode is formed;
A counter substrate on which a counter electrode is formed; and a display substrate on which the first display electrode, the first electrochromic layer, the second display electrode, and the second electrochromic layer are formed. And a laminating step of laminating the electrolyte so that the second electrochromic layer faces,
A method for manufacturing an electrochromic display device, comprising: A first display electrode forming step of forming a first display electrode on the display substrate by vacuum film formation;
A first electrochromic layer forming step of forming a first electrochromic layer corresponding to the first display electrode on the display substrate on which the first display electrode is formed;
A second display electrode forming step of forming a second display electrode on the inner side of the outer edge of the first display electrode by vacuum film formation on the display substrate on which the first electrochromic layer is formed;
A second electrochromic layer forming step of forming a second electrochromic layer corresponding to the second display electrode on the display substrate on which the second display electrode is formed;
A third display electrode forming step of forming a third display electrode inside the outer edges of the first display electrode and the second display electrode by vacuum film formation;
A third electrochromic layer forming step of forming a third electrochromic layer corresponding to the third display electrode on the display substrate on which the third display electrode is formed;
A counter substrate on which a counter electrode is formed; the first display electrode; the first electrochromic layer; the second display electrode; the second electrochromic layer; the third display electrode; A bonding step in which an electrochromic layer is formed, and a bonding step of bonding the electrolyte so that the counter electrode and the third electrochromic layer face each other,
A method for manufacturing an electrochromic display device, comprising:

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