WO2011118373A1

WO2011118373A1 - Electrochemical display element

Info

Publication number: WO2011118373A1
Application number: PCT/JP2011/055212
Authority: WO
Inventors: 倫生泉
Original assignee: コニカミノルタホールディングス株式会社
Priority date: 2010-03-24
Filing date: 2011-03-07
Publication date: 2011-09-29
Also published as: JPWO2011118373A1; JP4780255B1

Abstract

A substrate (20) on the non-observation side of a display element (1) is provided with a metal wiring (23) for supplying the current from a power bus (VDD) to a pixel electrode (25) via a thin-film transistor (Q2), and an inter-layer insulating film (24) which is formed so as to cover the thin-film transistor (Q2) and the metal wiring (23). The pixel electrode (25) is configured from a material having the same ionization tendencies as the deposition material within an electrolyte solution (30) or a higher ionization tendency than said deposition material, and is formed on the inter-layer insulating film (24). Moreover, the pixel electrode (25) is connected to the metal wiring (23) via a contact hole (24a). The substrate (20) is also provided with an insulating film (26) which is formed on the pixel electrode (25) so as to cover the contact hole (24a).

Description

Electrochemical display element

The present invention relates to an electrochemical display element that performs display by enclosing an electrolytic solution between a pair of substrates and causing an oxidation-reduction reaction of a deposition material in the electrolytic solution.

In recent years, display devices having excellent visibility and low power consumption have been demanded. At present, a self-luminous display element represented by CRT and PDP and a display element that modulates light from a light emitter (backlight) such as an LCD are generally used. The image is bright and easy to see, but it consumes more power.

From the viewpoint of low power consumption, it is desirable that the display element has a memory characteristic that keeps an image once displayed even in a non-powered state, and further, a low driving voltage is desirable. In recent years, electrochemical display elements such as an electrochromic display element (hereinafter also referred to as ECD) and an electrodeposition display element (hereinafter also referred to as ED) have been actively developed as display elements having such characteristics. . Both ECD and ED display by changing the light absorption state of the reactant alone due to the oxidation-reduction reaction on the electrode. That is, in ECD, display is performed by a reversible change (color change) of the light absorption state of the electrochromic material due to an oxidation-reduction reaction. On the other hand, in the ED, for example, display is performed by using silver deposition on an electrode from an electrolyte containing silver or a compound having silver in a chemical structure, and dissolution of silver in the electrolyte. These electrochemical display elements do not require additional members such as polarizing plates and backlights compared to LCDs, and are extremely advantageous in terms of cost reduction and process saving (ease of manufacturing). It has become.

By the way, in the configuration in which each pixel is arranged in a matrix form in the ED, it is provided corresponding to each pixel of the substrate arranged on the non-observation side among the pair of substrates sandwiching the electrolyte (electrolytic solution). A current from a power supply bus is supplied to a pixel electrode to be connected via a driving transistor (for example, TFT). In this configuration, in order to realize a high aperture ratio, it is necessary to separate the pixel electrode and the driving transistor from each other. For example, a driving transistor and a metal wiring connected to the driving transistor are covered with an insulating film, a pixel electrode is provided on the insulating film, and the pixel electrode and the metal wiring are connected through a contact hole provided in the insulating film. Thus, a large pixel electrode can be formed and a high aperture ratio can be realized. As described above, for example, Patent Document 1 discloses an example in which a pixel electrode and a metal wiring thereunder are connected via a contact hole.

JP 2007-11225 A (refer to paragraph [0022], FIG. 5)

In ED, when, for example, silver is used as a deposition material in the electrolytic solution, a metal material (for example, ITO) having the higher ionization tendency than silver or the same silver is generally used as a constituent material of the pixel electrode. This is because metal materials having a smaller ionization tendency than silver are platinum and gold, which are very expensive and difficult to use.

However, when the pixel electrode is made of a metal material having a greater ionization tendency or equivalent to that of the deposition material, the pixel electrode is etched (dissolved) by the electrolytic solution when the ED is driven. In particular, when the pixel electrode located in the contact hole is etched, the pixel cannot be driven, resulting in a point defect and display failure. As the material for the pixel electrode, it is advantageous from the viewpoint of the film formation process to use amorphous ITO, and it can be easily manufactured by a general-purpose device. However, for the etching of the pixel electrode, amorphous ITO was used. It is especially likely to occur.

The present invention has been made in order to solve the above-described problems, and an object of the present invention is to provide a deposition material in an electrolytic solution in which a pixel electrode and a lower-layer metal wiring and a driving transistor are separated from each other via an insulating film There is provided an electrochemical display element capable of suppressing the occurrence of display defects by suppressing the dissolution of the pixel electrode in the contact hole portion of the insulating film even when the pixel electrode is made of a material having a greater ionization tendency or equivalent. There is.

In the electrochemical display element of the present invention, an electrolytic solution is sealed between an observation-side substrate having a common electrode and a non-observation-side substrate having a pixel electrode, and the electrolytic solution according to the potential between the electrodes. An electrochemical display element that performs display by oxidation-reduction reaction of the deposition material therein, the substrate on the non-observation side supplying current from a power supply bus to the pixel electrode through a driving transistor And a first insulating film formed so as to cover the drive transistor and the metal wiring, and the pixel electrode has an ionization tendency equivalent to that of the deposition material or the deposition material. The metal wiring is made of a material having a higher ionization tendency than the first insulating film, and is formed on the first insulating film and through the contact hole provided in the first insulating film. Are connected, the substrate of the non-viewing side is further characterized by having a second insulating film formed on the pixel electrode so as to cover the contact hole.

According to the present invention, since the second insulating film is formed on the pixel electrode so as to cover the contact hole, the pixel electrode is made of a material having a greater ionization tendency or equivalent to the deposition material in the electrolytic solution. Even in the case where the pixel electrode is configured, it is possible to prevent the pixel electrode located in and on the contact hole from being dissolved by the electrolytic solution, and to reduce the occurrence of display defects due to the dissolution of the pixel electrode.

(A) is explanatory drawing which shows the pixel in a black display state while showing typically the schematic structure of 1 pixel of the display element of one Embodiment of this invention, (b) is in a white display state. It is explanatory drawing which shows this pixel. It is explanatory drawing which shows the equivalent circuit of the pixel of the said display element. It is sectional drawing which shows the detailed structure of the said pixel. It is sectional drawing which shows the other structure of the said pixel. It is sectional drawing which shows other structure of the said pixel. (A) is sectional drawing which shows the silver precipitation area | region when a partition part does not exist around each pixel, (b) is the case where the insulating film formed around each pixel functions as a partition part It is sectional drawing which shows the precipitation area | region of silver. It is explanatory drawing which shows the contact angle of two surfaces. It is explanatory drawing which shows the effective pixel area of the display element of each Example and a comparative example. It is explanatory drawing which shows the pixel defect occurrence rate for every driving frequency of the display element of each Example and a comparative example.

An embodiment of the present invention will be described below with reference to the drawings.

[Basic structure of display element]
FIGS. 1A and 1B are explanatory diagrams schematically showing a schematic configuration of one pixel of the display element 1 of the present embodiment. However, FIG. 1A shows a pixel in a black display state, and FIG. 1B shows a pixel in a white display state. The display element 1 is configured by an electrochemical display element called ED, and is configured by sealing an electrolytic solution 30 between an observation side substrate 10 and a non-observation side substrate 20. In the electrolytic solution 30, silver as a deposition material is dissolved, and silver ions 31 are present. The details of the electrolytic solution 30 will be described later.

The observation-side substrate 10 has a common substrate 11 made of, for example, a transparent glass substrate. A common electrode 12 (common electrode) common to the pixels 1a is formed on the common substrate 11. On the other hand, the non-observation side substrate 20 has a drive substrate 21 made of, for example, a transparent glass substrate. In addition, since the drive board | substrate 21 is arrange | positioned at the non-observation side, it does not need to be transparent. On the driving substrate 21, pixel electrodes 25 corresponding to the respective pixels 1a are formed. The

substrates

10 and 20 are bonded to each other so that the common electrode 12 and the pixel electrode 25 are on the inner side (so as to face each other with the electrolytic solution 30 therebetween).

Since the common electrode 12 is an observation side electrode, it needs to be transparent. For this reason, as the common electrode 12, a transparent electrode such as indium tin oxide (hereinafter referred to as ITO) is usually used. Here, in order to increase the etching resistance by the electrolytic solution 30, ITO is desirably crystalline. In the case of using amorphous ITO, it is necessary to anneal and crystallize at a temperature of 300 ° C. or higher. However, since no material that is damaged by heat is formed on the substrate 10 side on the observation side, the amorphous ITO is used. Thus, the common electrode 12 can be formed.

On the other hand, the pixel electrode 25 is made of a material having a larger ionization tendency than the deposition material in the electrolytic solution 30. For example, when silver is used as the deposition material, the pixel electrode 25 is often made of amorphous ITO, which is a metal oxide. This is because amorphous ITO can be formed at a low temperature (usually sputtering) at about 200 ° C., so that a transistor (for example, TFT) formed on the non-observation side drive substrate 21 and an insulating film covering the transistor are formed. This is because it does not cause damage. Further, since patterning by a photolithography technique is possible, similarly, the transistor or the like is not damaged. Thus, amorphous ITO is advantageous from the viewpoint of the film formation process of the pixel electrode 25, and the pixel electrode 25 can be easily formed by a general-purpose apparatus. The pixel electrode 25 may be made of a material (for example, silver) having the same ionization tendency as the deposition material in the electrolytic solution 30.

Next, the display principle of the display element 1 will be described.
In FIG. 1A, when the switch SW1 is closed, a negative voltage Vb equal to or higher than the threshold is applied to the pixel electrode 25 as the common voltage Vcom of the common electrode 12, and electrons are supplied from the common electrode 12 to the electrolyte 30. The common current Icom flows by being injected, and the silver ions 31 are reduced and the silver layer 32 is deposited at the position of the common electrode 12 facing the pixel electrode 25. When viewed from the common electrode 12 side, it looks black.

On the other hand, in FIG. 1B, when the switch SW1 is similarly closed and a positive voltage Vw equal to or higher than the threshold is applied to the pixel electrode 25 as the common voltage Vcom of the common electrode 12, FIG. The silver layer 32 deposited in step 1 is oxidized into silver ions 31 and dispersed in the electrolyte 30. The state in which the silver layer 32 is changed to the silver ion 31 is transparent when viewed from the common electrode 12 side. Therefore, the electrolyte solution 30 is colored white, or a diffusion layer is provided on the pixel electrode 25. Looks white. In this way, it is possible to switch between white and black display.

In FIGS. 1A and 1B, a voltage is applied to the pixel 1a of the display element 1 using the switch SW1, but if two thin film transistors (TFTs) are used per pixel as the switch SW1, each pixel 1a. Can be arranged in a matrix, and a so-called active matrix type display element 1 can be configured in which a voltage is applied to each pixel 1a to perform display.

[Detailed pixel configuration]
Next, a detailed configuration of one pixel of the display element 1 will be described.
FIG. 2 is an explanatory diagram showing an equivalent circuit of the pixel 1 a of the display element 1. In the pixel 1a, two thin film transistors Q1 and Q2 are formed. The thin film transistor Q1 is a selection transistor (switching transistor) for selecting the pixel 1a to be driven, and the thin film transistor Q2 is a drive transistor for driving the pixel 1a.

The thin film transistor Q1 is driven by the signal of the gate bus Gm and applies the signal of the source bus Sn when turned on to the gate electrode of the thin film transistor Q2. The thin film transistor Q2 has a potential difference between the common potential Vcom and the drive potential Vdd by the power supply bus VDD when the gate potential is raised by the thin film transistor Q1, that is, the voltage Vb described with reference to FIGS. Vw is applied between the common electrode 12 and the pixel electrode 25 to pass a current through the electrolytic solution 30. Depending on the potential between the common electrode 12 and the pixel electrode 25, silver as a deposition material in the electrolytic solution 30 causes an oxidation-reduction reaction, and thereby the pixel 1a may be blackened or whitened. it can.

Thus, since the display element 1 as the ED is a current-driven display element, a relatively large current instantaneously flows through each pixel 1a during driving. In order to prevent a voltage drop at this time, the power supply bus VDD needs to be thick. However, since the power supply bus VDD cannot be unnecessarily thickened in the width direction due to the balance with the pixel size, it is general that the power supply bus VDD is formed thicker.

Next, the configuration of the non-observation side substrate 20 in the pixel 1a will be described in more detail. FIG. 3 is a cross-sectional view showing a detailed configuration of the pixel 1a. On the drive substrate 21, a scanning bus Gm and gate electrodes of the thin film transistors Q1 and Q2 are formed. The gate electrode of the thin film transistor Q1 is connected to the scanning bus Gm. A gate insulating film 22 is formed on the drive substrate 21 so as to cover the scanning bus Gm and each gate electrode.

On the gate insulating film 22, the semiconductors of the thin film transistors Q1 and Q2 are formed by patterning, and the source bus Sn, the power supply bus VDD, the source / drain electrodes of the thin film transistors Q1 and Q2, and the metal wiring 23 are formed. One electrode of the source / drain electrodes of the thin film transistor Q1 is connected to the source bus Sn, and the other electrode is connected to the gate electrode of the thin film transistor Q2 through a contact hole 22a provided in the gate insulating film 22. Yes. One electrode of the source / drain electrodes of the thin film transistor Q2 is connected to the power supply bus VDD, and the other electrode is connected to the metal wiring 23. The other electrode may be formed integrally with the metal wiring 23.

Then, an interlayer insulating film 24 (first insulating film) is formed so as to cover the semiconductors of the thin film transistors Q1 and Q2, the source bus Sn, the power supply bus VDD, the source / drain electrodes of the thin film transistors Q1 and Q2, and the metal wiring 23. A pixel electrode 25 (first pixel electrode) is formed on the interlayer insulating film 24. The pixel electrode 25 is connected to the metal wiring 23 through a contact hole 24 a provided in the interlayer insulating film 24. Therefore, when the thin film transistor Q2 is turned on, the current from the power supply bus VDD is supplied to the pixel electrode 25 via the thin film transistor Q2 and the metal wiring 23.

An insulating film 26 (second insulating film) is formed on the pixel electrode 25 so as to cover the contact hole 24a (with a size larger than the contact hole 24a). A porous metal oxide electrode 27 (second pixel electrode) is patterned on the interlayer insulating film 24 for each pixel 1 a so as to cover the pixel electrode 25 and the insulating film 26. The porous metal oxide electrode 27 is electrically connected to the pixel electrode 25 in the non-formation region 25 a of the insulating film 26. Details (materials and formation method) of the insulating film 26 and the porous metal oxide electrode 27 will be described later.

As described above, the insulating film 26 is formed so as to cover the contact hole 24a. Therefore, even in the case where the pixel electrode 25 is made of amorphous ITO having a smaller ionization tendency than silver, the contact hole 24a and the contact hole are also formed. It can suppress that the pixel electrode 25 located on 24a melt | dissolves with the electrolyte solution 30. FIG. Accordingly, the dissolution of the pixel electrode 25 in the contact hole 24a prevents the current from the power supply bus VDD from being supplied to the pixel 1a, resulting in a defective pixel, which can reduce display defects.

Further, since the porous metal oxide electrode 27 that is electrically connected to the pixel electrode 25 in the non-formation region 25a is provided as the second pixel electrode so as to cover the pixel electrode 25 and the insulating film 26, A region that does not contribute to display due to the provision of the insulating film 26 is covered with the porous metal oxide electrode 27 to contribute to display. As a result, although the pixel electrode 25, the thin film transistors Q1 and Q2, and the metal wiring 23 are separated from each other through the interlayer insulating film 24, an insulating film is formed on the pixel electrode 25 even though a high aperture ratio is achieved. By providing 26, it is possible to avoid a decrease in the aperture ratio.

Further, as shown in FIG. 3, if the porous metal oxide electrode 27 is also formed in the non-formation region of the pixel electrode 25 on the insulating film 24, the aperture ratio of the pixel 1a can be further increased. In FIG. 3, the porous metal oxide electrode 27 is provided so as to cover the entire insulating film 26, but the porous metal oxide electrode 27 does not necessarily need to cover the entire insulating film 26. You may cover only a part of. In short, the porous metal oxide electrode 27 may be electrically connected to the pixel electrode 25 somewhere. Thus, even if the porous oxide electrode 27 covers a part of the insulating film 26, the porous metal oxide electrode 27 is formed so as to extend to the non-formation region of the pixel electrode 25 on the insulating film 24. (Or forming so as to cover a part of the non-formed region), or forming the cover so as to cover all the non-formed region, the decrease in the aperture ratio can be further reduced or prevented. Further, the porous metal oxide electrode 27 may be formed larger than the non-formation region 25a of the pixel electrode 25, or may be formed so as to cover the non-formation region 25a.

In order to maintain or increase the aperture ratio, it is sufficient that the porous metal oxide electrode 27 has an area that can compensate for the decrease in the aperture ratio due to the provision of the insulating film 26. Alternatively, it may be secured in a region where the pixel electrode 25 is not formed. That is, the porous metal oxide electrode 27 may be formed so as to cover a region where the pixel electrode 25 is not formed on the interlayer insulating film 24.

As described above, by providing the porous metal oxide electrode 27 (second pixel electrode) on the pixel electrode 25 (first pixel electrode), in addition to maintaining and expanding the aperture ratio, the entire electrode Increasing the thickness of the wire also has the advantage that the resistance value of electricity decreases and electricity flows easily.

The advantage of providing an electrode made of a porous metal oxide as the second pixel electrode will be described later. Instead of the porous metal oxide electrode 27, the same metal material (amorphous ITO) as the pixel electrode 25 is used. It is also possible to form the electrode made of as the second pixel electrode. Even in the latter case, the effect of avoiding a decrease in the aperture ratio due to the insulating film 26 or increasing the aperture ratio remains unchanged.

[Other pixel configurations]
FIG. 4 is a cross-sectional view showing another configuration of the pixel 1a. As shown in the drawing, the insulating film 26 described above may be provided on the peripheral edge of each pixel 1 a so as to surround each pixel 1 a corresponding to each pixel electrode 25. That is, the insulating film 26 may be a bank provided so as to separate

adjacent pixels

1a and 1a. The porous metal oxide electrode 27 of each pixel 1 a may be formed over the entire region surrounded by the insulating film 26 and may be partitioned by the insulating film 26. In this configuration, in each pixel 1a, the porous metal oxide electrode 27 does not cover a part of the insulating film 26, but the area is larger than the pixel electrode 25, so that the aperture ratio is improved.

Further, unlike the configuration of FIG. 3, it is not necessary to pattern the porous metal oxide electrode 27 for each pixel 1a after the formation of the porous metal oxide electrode 27, so that the manufacturing process can be simplified. In addition, when the porous metal oxide electrode 27 is formed by patterning for each pixel 1a as shown in FIG. 3, sharp edges 27a such as edges (corner portions) appear on the porous metal oxide electrode 27. FIG. In this configuration, since the end of the porous metal oxide electrode 27 is in contact with the insulating film 26, the sharpened portion does not appear in the porous metal oxide electrode 27, and the sharpened portion is deteriorated by the electrolytic solution 30. The situation can be avoided and the durability can be improved.

FIG. 5 is a cross-sectional view showing still another configuration of the pixel 1a. As shown in the figure, the above-described insulating film 26 is formed at substantially the same height as the gap between the

substrates

10 and 20, and a partition wall portion 26a that suppresses movement of silver ions in the electrolytic solution 30 to adjacent pixels. You may also serve.

As shown in FIG. 6 (a), ambient when the partition wall is not present in the pixels 1a, the pixels 1a ₁ performing black display is affected by the potential state of the adjacent pixels 1a _2, the silver ion of the pixels 1a ₁ It moves in the direction of the adjacent pixel 1a ₂ that should not be moved, and black is displayed. That is, the silver layer 32 to be formed on the pixel 1a ₁ that performs black display extends to the adjacent pixel 1a ₂ to display black. This phenomenon is also called bleeding, and causes a reduction in the definition of the display image.

In contrast, as shown in FIG. 6 (b), when the insulating film 26 functions as a partition wall 26a, the silver ions dissolved in the electrolytic solution 30, adjacent pixels 1a from pixels 1a ₁ performing black display _The movement to ₂ can be suppressed by the insulating film 26 (partition wall 26a). As a result, the silver layer 32 to be formed on the pixel 1a ₁ can be prevented from spreading to the adjacent pixel 1a ₂ , and deterioration of display quality due to bleeding can be avoided. Further, since the insulating film 26 also serves as the partition wall portion 26a, it is not necessary to separately form a partition wall portion for suppressing the bleeding, and the configuration of the display element 1 can be simplified.

The insulating film 26 may be formed so as to completely fill the gap between the

substrates

10 and 20. In this case, since the distance between the electrodes of each pixel 1a can be kept constant, display unevenness in the entire display area including all the pixels 1a can be eliminated.

[Electrolyte]
Next, the detail of the electrolyte solution 30 mentioned above is demonstrated.
The electrolytic solution 30 contains silver or a compound containing silver in the chemical structure, and silver ions are present in the electrolytic solution 30. Here, silver or a compound containing silver in the chemical structure is a general term for compounds such as silver oxide, silver sulfide, metallic silver, silver colloidal particles, silver halide, silver complex compounds, and silver ions. At this time, any state state species such as a solid state, a solubilized state in a liquid, or a gas state, and a charged state species such as neutral, anionic, and cationic are not particularly limited.

The concentration of silver ions contained in the electrolytic solution 30 is preferably 0.2 mol / kg ≦ [Ag] ≦ 2.0 mol / kg. When the silver ion concentration is less than 0.2 mol / kg, the driving speed is delayed due to a dilute silver solution. Conversely, when the silver ion concentration is greater than 2 mol / kg, the solubility deteriorates and precipitates during low-temperature storage. Tends to occur, which is disadvantageous.

In addition, the electrolyte solution 30 preferably has a viscosity at 25 ° C. of 0.1 mPa · s or more and less than 100 mPa · s, and the amount of the polymer binder with respect to the solvent is preferably less than 10% by weight. Furthermore, the electrolytic solution 30 may be configured by selecting an organic solvent, an ionic liquid, a redox active substance, a supporting electrolyte, a complexing agent, a white scattering material, a polymer binder, and the like as necessary.

[Second insulating film]
Next, details of the insulating film 26 as the second insulating film will be described.
As the material of the insulating film 26, a material having good insulating properties and not deteriorating the semiconductor material of the switching elements (thin film transistors Q1 and Q2) at the time of film formation can be used. For example, as the insulating film 26, inorganic oxides such as silicon oxide, inorganic nitrides such as silicon nitride, or polyimide, polyamide, polyester, polyacrylate, photo radical polymerization type, photo cation polymerization type photo curable resin, An organic compound such as a copolymer containing an acrylonitrile component, polyvinylphenol, polyvinyl alcohol, a novolac resin, cyanoethyl pullulan, or parylene is applicable. Further, the insulating film 26 may be formed by superposing a plurality of layers of an organic material and an inorganic material.

As a method of forming the insulating film 26, for example, there are a method of patterning in a predetermined shape after coating the entire surface, and a method of patterning and forming directly in a predetermined shape. In the case of the former method, it is desirable to form a spin coat film using the above-mentioned photocurable resin, leave the pattern slightly larger than the shape of the contact hole 24a through the steps of pattern exposure and development. If the formation pattern of the insulating film 26 is too large, the contact area between the porous metal oxide electrode 27 and the pixel electrode 25 is reduced and the resistance during conduction is increased. Conversely, if the formation pattern is too small, the contact hole 24 a The protection function is lost. Note that the coating method of the film forming material is not limited to the above-described spin coating, and may be spray coating, slit coating, dipping coating, or the like. On the other hand, in the case of the latter method, it is possible to apply coating methods, such as an inkjet method, a dispenser method, and screen printing.

[Porous metal oxide electrode]
Next, details of the porous metal oxide electrode 27 will be described.
In general, as the main component of the fine particles constituting the electrode having a porous structure, metals such as Cu, Al, Ag and Pd, metal oxides such as ITO, SnO ₂ , TiO ₂ and ZnO, carbon nanotubes, glassy carbon, Examples of the carbon electrode include diamond-like carbon and nitrogen-containing carbon. From the viewpoint of durability of the pixel electrode 25, the porous metal oxide electrode 27 is particularly preferably a metal oxide such as ITO, SnO ₂ and ZnO. Is preferably selected from.

Here, the “porous structure” has a structure in which ionic species contained in the electrolytic solution can move inside a so-called nanoporous structure in which an infinite number of nanometer-sized pores exist in the electrode. Say. Therefore, the average particle diameter of the fine particles constituting the porous metal oxide electrode 27 is preferably about 5 nm to 30 nm. As the fine particles, those having an arbitrary shape such as an indeterminate shape, a needle shape, a spherical shape and the like can be used.

By providing the porous metal oxide electrode 27 having such a porous structure, silver as a deposition material is supported in the porous metal oxide electrode 27, and current from the power supply bus VDD is supplied to the pixel in this portion. Since it is supplied via the electrode 25, the oxidation-reduction reaction speed (driving speed) at the time of current supply can be increased.

As a method of forming the porous metal oxide electrode 27, there are a method of patterning into a predetermined shape after coating the entire surface, and a method of directly patterning and forming in a predetermined shape, as in the case of the insulating film 26. In the case of the former method, it is desirable to apply a porous metal oxide and then perform patterning by a photolithography technique, which is particularly effective for manufacturing the display element 1 shown in FIG. As a method for applying the metal oxide, spin coating, spray coating, slit coating, dipping coating, or the like can be used. The metal oxide is a content dispersed in a solvent such as alcohol.

On the other hand, as the latter method, a method in which a material is allowed to fly in a non-contact manner such as an ink jet method or a dispenser method is desirable, and is particularly effective for manufacturing the display element 1 shown in FIGS. In other words, by using the insulating film 26 serving as a bank as a separator and subjecting the insulating film 26 to a liquid repellent treatment, the porous metal oxide can be satisfactorily patterned for each pixel.

In any method, after coating, the solvent is evaporated by drying by heating, and a porous metal oxide electrode is formed. The heating temperature (150 to 200 ° C.) required to generate the porous material is lower than the heating temperature (300 to 400 ° C.) required to crystallize the ITO. The porous metal oxide electrode 27 can be formed on the pixel electrode 25 without causing much damage to the transistor formed in this step and the insulating film covering the transistor.

Note that a method of applying a liquid using a bank is widely known, and particularly, it is often used as a method of coating a light emitting material of an organic EL display or a method of coating a liquid crystal color filter.

〔Example〕
Next, examples of the display element 1 of the present embodiment will be described as Examples 1 to 3. For comparison with Examples 1 to 3, Comparative Example 1 is also shown.

Example 1
In Example 1, the display element 1 of FIG. 3 was produced by the following procedure.

<Preparation of electrolyte>
In 2.5 g of dimethyl sulfoxide (hereinafter referred to as DMSO), 90 mg of sodium iodide and 75 mg of silver iodide were added and completely dissolved. The solution was stirred for 1 hour to form a solution. To this solution, polyethylene glycol having an average molecular weight of about 100,000 (hereinafter referred to as PEG) and titanium oxide powder were added and mixed to prepare a gel-like white electrolytic solution 30. At this time, PEG was 5 wt% of the electrolytic solution 30, and the titanium oxide powder was 30 wt% of the electrolytic solution 30.

<Preparation of the substrate on the observation side>
A glass substrate was used as the common substrate 11. Then, on the common substrate 11, a crystalline ITO that is a transparent conductive film is formed to a thickness of 150 nm by a sputtering method, and a common electrode 12 (common to each pixel 1a) is formed on the entire surface. An observation-side substrate 10 was produced.

<Preparation of non-observation side substrate>
[Step 1: Formation of base]
A glass substrate is used as the driving substrate 21, and a TFT array having two TFTs (thin film transistors Q 1 and Q 2) per pixel is formed on the driving substrate 21 in a two-dimensional matrix form so as to cover the TFT array. An interlayer insulating layer 24 was formed, and a thin pixel electrode 25 was formed on the interlayer insulating film 24 using amorphous ITO corresponding to each pixel 1a. At this time, the pixel electrode 25 is connected to the metal wiring 23 and the thin film transistor Q2 through a contact hole 24a provided in the interlayer insulating film 24. The substrate formed up to the pixel electrode 25 on the drive substrate 21 is referred to as the base of the substrate 20 here.

It should be noted that the process up to the production of the base, that is, the formation of the pixel electrode 25 can be performed by a known technique. For example, it is possible to form up to the pixel electrode 25 by a technique widely known for ECD, which is the same current drive type element as the display element 1, an organic EL display element, and the like.

[Step 2: Formation of second insulating film]
Next, an insulating film 26 as a second insulating film was formed on the base pixel electrode 25 formed in Step 1 so as to cover the contact hole 24a. More specifically, a coating type photosensitive acrylic resin (JSR, model number: PC403) was formed on the base at a spin coat of 3000 rpm. The thickness of the resin was 0.5 μm. Subsequently, using a predetermined photomask, exposure was performed with an irradiation light amount of 200 mJ / cm ² , and then development and baking were performed. The development was performed for 1 minute with a predetermined developer TMAH (tetramethylammonium hydroxide) 0.238 wt% aqueous solution. Firing was performed at 220 ° C. for 1 hour.

[Step 3: Application of porous metal oxide electrode material]
Next, porous ITO was applied to cover the pixel electrode 25 and the insulating film 26 on the pixel electrode 25 to form a porous ITO film having an average film thickness of 0.5 μm. For the application, a spray application apparatus (STS600 manufactured by YIDY MECATOR SOLUTIONS Co., Ltd.) was used. The coating conditions at this time are as follows.
・ Nozzle model number of spray gun: Atmax nozzle AM25 (manufactured by Atmax Co., Ltd.)
・ Atomization air: Nitrogen gas (N ₂ )
・ Flow rate of atomizing air: 8L / min
-Coating liquid (ITO ink) Model number: X806CN27S (manufactured by Sumitomo Metal Mining Co., Ltd.)
・ Coating liquid flow rate: 7mL / min
・ Nozzle discharge speed: 300mm / sec ・ Nozzle-drive substrate distance: 60mm

[Step 4: Patterning of porous metal oxide electrode]
The porous ITO film formed in step 3 was patterned by an existing photolithography technique and divided into a plurality of porous metal oxide electrodes 27. At this time, the plurality of porous metal oxide electrodes 27 were formed so that the pixel pitch was 200 μm and the size per pixel was 150 μm × 150 μm. Details of patterning are as follows.

A resist material (model number: OFPR800LB) manufactured by Tokyo Ohka Kogyo Co., Ltd. was applied at a spin coating condition of 1000 rpm, and then dried at 80 ° C. for 5 minutes on a hot plate. Then, using a photomask of a predetermined size, pattern exposure was performed with an exposure amount of 120 mJ / cm ² , and then development was performed with a predetermined developer (TMAH (tetramethylammonium hydroxide) 2.38 wt% aqueous solution) for 120 seconds. Thereafter, etching was performed for 200 seconds using an etching ferric salt solution manufactured by Hayashi Pure Chemical Industries. The resist material was peeled off by using a NaOH 2 wt% aqueous solution, followed by drying in an oven at 80 ° C. for 1 hour after peeling.

<Application of sealant>
Next, a thermosetting olefin-based sealant was applied to the peripheral edge of the substrate 20 on which the porous metal oxide electrode 27 was formed, using a dispenser, except for the inlet for the electrolytic solution 30. Then, by arranging a 30 μm bead spacer in the sealant, the gap between the

substrates

10 and 20 was set to be 30 μm.

<Board bonding>
After the

substrates

10 and 20 were bonded to each other through the above-described sealing agent, the sealing agent was cured by heating and pressing to produce an empty cell with an empty interior. Subsequently, the electrolytic solution 30 is injected into the empty cell using a vacuum injection method used in the manufacture of a liquid crystal panel, and the injection port of the electrolytic solution 30 is sealed with an ultraviolet curable adhesive. The display element 1 of Example 1 was obtained.

(Example 2)
In Example 2, the display element 1 of FIG. 4 was produced. The second embodiment is the same as the first embodiment except that a part of the process of <production of the non-observation side substrate> described in the first embodiment is changed as follows.

<Preparation of non-observation side substrate>
[Step 2: Formation of second insulating film]
An insulating film 26 as a second insulating film was formed so as to surround the pixel 1a corresponding to the base pixel electrode 25 formed in step 1 and to cover the contact hole 24a. More specifically, a coating-type photosensitive acrylic resin (JSR, model number: PC403) was formed on the base at a spin coat of 700 rpm. The thickness of the resin was 2.0 μm. Subsequently, using a predetermined photomask, exposure was performed with an irradiation light amount of 200 mJ / cm ² , and then development and baking were performed. Development was performed for 2 minutes with a 0.238 wt% aqueous solution of a predetermined developer TMAH (tetramethylammonium hydroxide). Firing was performed at 220 ° C. for 1 hour.

In Example 2 and Example 3 to be described later, the degree of non-affinity (ease of repelling) of the liquid material (porous ITO to be applied next) with respect to the surface of the insulating film 26 depends on the insulating film 26 on the substrate. Surface of at least one of the surface of the insulating film 26 and the non-forming region of the insulating film 26 so as to be higher than the non-forming region (including the surface of the non-forming region 25a on the pixel electrode 25 and the surface of the interlayer insulating film 24). It is preferable to perform the treatment. That is, at least one of the surface of the insulating film 26 and the non-formed region is surface-treated so that the liquid material is repelled on the surface of the insulating film 26 than on the non-formed region of the insulating film 26 on the substrate. Is desirable. Even if a large amount of liquid material is ejected compared to the thickness of the thin film layer (porous metal oxide electrode 27) to form the porous metal oxide electrode 27 next by such surface treatment, the liquid material The liquid material can be filled only in a predetermined region of each pixel 1a, that is, a region where the insulating film 26 is not formed. That is, the insulating film 26 can function as a bank.

Here, as the above-described surface treatment, for example, a gas containing fluorine or a fluorine compound is used as an introduction gas, and the plasma irradiation is performed in a reduced pressure atmosphere or an atmospheric pressure atmosphere containing a fluorine compound and oxygen or an atmospheric pressure. Plasma treatment is mentioned. Examples of the gas containing fluorine or a fluorine compound include CF ₄ , SF ₆ , and CHF ₃ . In Example 2, CF ₄ plasma treatment (pressure: 5 Pa, output: 5 W, CF ₄ flow rate: 7 sccm, time: 1 minute) is performed, and the contact angle between the insulating film 26 and the liquid material (porous ITO material) is about The angle was 60 °.

The contact angle refers to an angle α (°) between the surface S and the surface L at the contact point between the solid surface S and the liquid surface L as shown in FIG. The larger the contact angle α, the higher the non-affinity of the liquid with respect to the solid. In order to surely obtain the effect of the surface treatment described above, the contact angle of the liquid material (porous ITO material) with respect to the surface of the insulating film 26 is set to 50 ° or more, and the contact angle with respect to the non-formation region of the insulating film 26 is set to 20 °. The following is preferable.

[Step 3: Application of porous metal oxide electrode material]
Porous ITO, which is a liquid material, is dropped into the region surrounded by the insulating film 26 formed in step 2 by an inkjet method. The ejection amount in the ink jet method is set to an amount such that a desired thickness is obtained when the volume is reduced by the heat treatment after the application of porous ITO. In addition, you may make it become desired thickness by discharging porous ITO again after drying, and performing an overlay process.

In the second embodiment, the size (height and width) of the insulating film 26 is defined with respect to the size of the droplet of the liquid material to be discharged, whereby the thin film layer (porous metal oxide electrode 27). Even when a large amount of liquid material is ejected compared to the thickness of the liquid material, the liquid material does not overflow over the insulating film 26, and the liquid material is filled in a predetermined region. In the case where the liquid material is a material containing a solvent, the volume of the liquid material is reduced by removing the solvent component by performing heat treatment and / or pressure reduction treatment after filling the liquid material, and the insulating film 26 is not formed. A thin film layer is formed in the region. At this time, the surface of the non-formation region of the insulating film 26, that is, the substrate surface is surface-treated so as to exhibit affinity (lyophilicity) as described above, and thus the thin film layer is suitably adhered.

The ink jet method may be either a piezo jet method or a method of discharging by the generation of bubbles due to heat, but the piezo jet method is preferred because there is no change in the quality of the fluid due to heating. In Example 2, a porous ITO with a film thickness of 1.2 μm was formed using an inkjet apparatus having a piezo head KM512M manufactured by Konica Minolta IJ Co., Ltd.

In Example 2, the insulating film 26 becomes a bank, and the porous metal oxide electrode 27 is separated by the insulating film 26 simultaneously with the formation of the porous metal oxide electrode 27. Therefore, [Step 4: [Pattern Formation of Porous Metal Oxide Electrode] is unnecessary.

(Example 3)
In Example 3, the display element 1 of FIG. 5 was produced. Note that Example 3 is the same as Example 2 except that a part of the process of <production of the non-observation side substrate> described in Example 2 is changed as follows.

<Preparation of non-observation side substrate>
[Step 2: Formation of second insulating film]
An insulating film 26 as a second insulating film was formed so as to surround the pixel 1a corresponding to the base pixel electrode 25 formed in step 1 and to cover the contact hole 24a. More specifically, a negative photosensitive photoresist material SU-8 3050 (manufactured by Kayaku Microchem Co., Ltd.) is spin-coated at a rotation speed of 1000 rpm, and prebaked on a hot plate at 100 ° C. for 30 minutes. Went.

After pre-baking, ultraviolet rays were irradiated with a collimated light exposure machine through a photomask having a partition pattern and an irradiation light amount of 400 mJ / cm ² , followed by heat treatment on a hot plate at 100 ° C. for 10 minutes. . After the heat treatment, development processing is performed using propylene glycol monomethyl ether acetate (PGMEA) solution, the photoresist material not irradiated with ultraviolet rays is removed, rinse treatment is performed with isopropyl alcohol (IPA) solution, By drying, a partition structure (insulating film 26, partition part 26a) having a height of 25 μm could be obtained. The width of the partition wall structure was set to 15 μm by a photomask pattern.

(Comparative Example 1)
In Comparative Example 1, a part of the process of <Manufacturing the Non-observation Side Substrate> described in Example 1, that is, [Step 2: Formation of the second insulating film] is omitted, and a display element is manufactured These are the same as in Example 1.

[Drive inspection]
Next, a driving test was performed using the display elements of Examples 1 to 3 and Comparative Example 1. The inspection procedure is as follows.

In Examples 1 to 3 and Comparative Example 1, the pixel pitch of each display element was 0.2 mm, and the effective pixel area R was 70 mm × 50 mm as shown in FIG. Therefore, the number of pixels in the effective pixel area R is (70 / 0.2) × (50 / 0.2) = 350 × 250 = 87500. Further, here, the effective pixel area R is divided into eight and the following inspection is performed. Therefore, the number of inspection pixels per area is 87500 / 8≈10000.

First, voltage application and non-application were repeated for all pixels in each area, and white / black display was alternately repeated. Note that black display by voltage application was performed so that the contrast was 10. Note that the contrast 10 indicates that the luminous reflectance (Y value) ratio between white and black is 10: 1.

Next, when the drive count (black display count) reaches 1000, the display image is captured for each area by the scanner, and the captured image is converted into digital data, and the number of pixels whose contrast is less than 10 is counted. did.

For example, assume that the image data (luminance data) of the captured image is 8 bits from “0” (black) to “255” (white). In the white display state when no voltage is applied, the image data of the white display pixel is “240”, and the image data “50” of the black display pixel is compared with the image data “240” of the white display pixel. Corresponds to a contrast of 10. In this case, since the pixels having the image data “51” or more are pixels that do not satisfy the contrast 10 (pixels in which black does not appear), the number of such pixels is counted.

Next, the pixel defect occurrence rate is calculated for each area. This pixel defect occurrence rate (%) is expressed by the following equation.
Pixel defect occurrence rate (%) = {(number of defective pixels in one area) / (number of inspection pixels in one area)} × 100

Finally, the average value of the pixel defect occurrence rate for all areas is calculated. Such a process was performed every time the number of driving times reached 10,000 times and 100,000 times.

FIG. 9 shows the pixel defect occurrence rate (average value) for each driving frequency of the display elements of Examples 1 to 3 and Comparative Example 1. As shown in the figure, in the display elements of Examples 1 to 3, the pixel defect occurrence rate was 1% or less even when the number of driving times reached 100,000. The pixel defect occurrence rate increased as the number of times increased to 1000 times, 10,000 times, and 100,000 times, and the pixel defect occurrence rate was 90% or more when driven 100,000 times.

For confirmation, the display element of Comparative Example 1 was disassembled and the contact hole portion was observed. As a result, ITO as the pixel electrode disappeared, and conduction with the metal wiring connected to the pixel electrode through the contact hole was confirmed. It became clear that it was impossible to remove. Therefore, it can be said that the structure in which the insulating film is formed so as to cover the contact hole as in Examples 1 to 3 is very effective in protecting the pixel electrode in the contact hole portion.

The electrochemical display element described in the above embodiment can also be expressed as follows, and has the following effects.

In the electrochemical display element of the present embodiment, an electrolytic solution is sealed between an observation side substrate having a common electrode and a non-observation side substrate having a pixel electrode, and the electrolysis is performed according to the potential between the electrodes. An electrochemical display element that performs display by oxidation-reduction of a deposition material in a liquid, wherein the non-observation side substrate supplies a current from a power supply bus to the pixel electrode through a driving transistor. And a first insulating film formed so as to cover the drive transistor and the metal wiring, and the pixel electrode has an ionization tendency equal to or equal to the deposition material. The metal is made of a material having a higher ionization tendency than the material, is formed on the first insulating film, and is formed on the metal through a contact hole provided in the first insulating film. Is connected to the line, the substrate of the non-viewing side is further is configured to have a second insulating film formed on the pixel electrode so as to cover the contact hole.

According to the above configuration, on the non-observation side substrate, the current from the power supply bus is supplied to the pixel electrode (first pixel electrode) via the drive transistor and the metal wiring. Therefore, a current corresponding to the potential between the common electrode on the observation side and the pixel electrode on the non-observation side flows through the electrolytic solution, and on the electrode side serving as the negative electrode, a deposition material (for example, silver) in the electrolytic solution by a reduction reaction The deposition material is dissolved by the oxidation reaction on the electrode side that becomes the positive electrode. By such deposition / dissolution of the deposition material, black / white display and switching thereof can be performed.

The driving transistor and the metal wiring are covered with a first insulating film, and the pixel electrode is connected to the metal wiring through a contact hole provided in the first insulating film. Thus, the pixel electrode, the drive transistor, and the metal wiring are in separate layers via the first insulating film.

In such a configuration, since the second insulating film is formed on the pixel electrode so as to cover the contact hole, the pixel electrode is made of a material having a higher ionization tendency or equivalent to the deposition material in the electrolytic solution. Even in the case where the pixel electrode is configured, it is possible to prevent the pixel electrode located in and on the contact hole from being dissolved by the electrolytic solution, and to reduce the occurrence of display defects due to the dissolution of the pixel electrode.

In the electrochemical display element of the present embodiment, when the pixel electrode is a first pixel electrode, the second electrode is electrically connected to the first pixel electrode in a region where the second insulating film is not formed. There may be further provided a second pixel electrode formed so as to cover at least a part of the first pixel electrode.

In this case, by providing the second insulating film over the first pixel electrode, the reduction in the aperture ratio of the pixel corresponding to the first pixel electrode is at least reduced or reduced by providing the second pixel electrode. Can be prevented, and the aperture ratio can be increased.

In the electrochemical display element of the present embodiment, the second pixel electrode may be formed to have a larger area than a region where the second insulating film is not formed in the first pixel electrode. In addition, the first pixel electrode may be formed so as to cover the entire region where the second insulating film is not formed. The second pixel electrode may be formed so as to extend to a non-formation region of the first pixel electrode on the first insulating film (so as to cover a part of the non-formation region). Alternatively, it may be formed so as to cover (all of) the non-formation region of the first pixel electrode on the first insulating film. Furthermore, the second pixel electrode may be formed to have a larger area than the first pixel electrode.

By forming the second pixel electrode in this manner, the aperture ratio of the pixel corresponding to the first pixel electrode is reduced by providing the second insulating film on the first pixel electrode. By providing the second pixel electrode, at least it can be reduced or prevented, and the aperture ratio can be increased.

The electrochemical display element of the present embodiment has a plurality of pixels and a plurality of the pixel electrodes corresponding to the plurality of pixels as first pixel electrodes, and the second insulating film includes It may be provided so as to surround each pixel corresponding to the first pixel electrode. The electrochemical display element is formed in a region partitioned by the second insulating film so as to be electrically connected to the first pixel electrode in a region where the second insulating film is not formed. A pixel electrode may be further included.

In this configuration, after the second pixel electrode is formed, it is not necessary to pattern the second pixel electrode for each pixel, and the manufacturing process can be simplified. In addition, since the edge of the second pixel electrode is in contact with the second insulating film and the edge (corner) of the second pixel electrode does not appear, it is possible to avoid the edge from being deteriorated by the electrolytic solution. And durability can be improved.

In the electrochemical display device of this embodiment, the second insulating film may also serve as a partition wall portion that suppresses movement of ions in the electrolytic solution to adjacent pixels.

In this configuration, the ions in the electrolytic solution can be prevented from moving to adjacent pixels by the second insulating film (partition wall portion), and deterioration of display quality due to bleeding can be avoided. Further, by forming the second insulating film, it is not necessary to separately form the partition wall portion, so that the structure of the display device can be simplified.

In the electrochemical display element of the present embodiment, the second pixel electrode is formed by applying and drying a liquid material, and the non-affinity of the liquid material with respect to the surface of the second insulating film. And at least one of the surface of the second insulating film and the non-formed region is surface-treated so as to be higher than the non-formed region of the second insulating film on the non-observation side substrate. Also good.

Even if a larger amount of liquid material is ejected than the thickness of the second pixel electrode to form the second pixel electrode by such surface treatment, the liquid material passes over the second insulating film and is adjacent. The liquid material can be filled only in a predetermined region of each pixel, that is, a region where the second insulating film is not formed.

In particular, if the contact angle of the liquid material with respect to the surface of the second insulating film is 50 ° or more and the contact angle of the liquid material with respect to the non-formation region is 20 ° or less, the effect of the surface treatment described above can be obtained. You can definitely get it.

In each pixel of the electrochemical display element of the present embodiment, the second pixel electrode may be formed to have a larger area than the first pixel electrode.

As described above, since the second pixel electrode is formed, a high aperture ratio can be reliably realized.

In the electrochemical display element of this embodiment, the second pixel electrode may be made of a porous metal oxide.

Since the deposition material is supported in the porous metal oxide, and the current from the power supply bus is supplied to this portion via the first pixel electrode, the oxidation-reduction reaction rate (drive speed) at the time of current supply is increased. be able to.

The present invention can be used for an electrochemical display element such as an ED constituting various display devices such as an electronic book.

1 Display element (electrochemical display element)
1a pixel 10 substrate 12 common electrode (common electrode)
20 Substrate 23 Metal wiring 24 Interlayer insulating film (first insulating film)
24a contact hole 25 pixel electrode (first pixel electrode)
25a Non-formation region 26 Insulating film (second insulating film)
26a Partition part 27 Porous metal oxide electrode (second pixel electrode)
30 Electrolyte Q2 Thin film transistor (drive transistor)
VDD power bus

Claims

An electrolytic solution is sealed between an observation-side substrate having a common electrode and a non-observation-side substrate having a pixel electrode, and the deposition material in the electrolytic solution is subjected to an oxidation-reduction reaction according to the potential between the electrodes. An electrochemical display element that performs display,
The non-observation side substrate is:
Metal wiring for supplying current from the power supply bus to the pixel electrode via the driving transistor;
A first insulating film formed to cover the drive transistor and the metal wiring,
The pixel electrode is made of a material having an ionization tendency that is equal to or greater than that of the deposition material, and is formed on the first insulating film, and the first insulating film Is connected to the metal wiring through a contact hole provided in the
The non-observation side substrate further includes:
An electrochemical display element comprising a second insulating film formed on the pixel electrode so as to cover the contact hole.
When the pixel electrode is a first pixel electrode,
The semiconductor device further includes a second pixel electrode formed so as to be electrically connected to the first pixel electrode in a region where the second insulating film is not formed and to cover at least a part of the second insulating film. The electrochemical display element according to claim 1.
3. The electricity according to claim 2, wherein the second pixel electrode is formed to have a larger area than a region where the second insulating film is not formed in the first pixel electrode. Chemical display element.
3. The electrochemical display element according to claim 2, wherein the second pixel electrode is formed so as to cover all the non-formation region of the second insulating film of the first pixel electrode. .
3. The electrochemical display element according to claim 2, wherein the second pixel electrode is formed so as to extend to a non-formation region of the first pixel electrode on the first insulating film.
The electrochemical display element according to claim 2, wherein the second pixel electrode is formed so as to cover a non-formation region of the first pixel electrode on the first insulating film.
The electrochemical display element according to claim 2, wherein the second pixel electrode is formed so as to have an area larger than that of the first pixel electrode.
The electrochemical display element has a plurality of pixels, and a plurality of the pixel electrodes corresponding to the plurality of pixels as first pixel electrodes,
The second insulating film is provided so as to surround each pixel corresponding to each first pixel electrode,
The electrochemical display element includes a second pixel electrode formed in a region partitioned by the second insulating film so as to be electrically connected to the first pixel electrode in a region where the second insulating film is not formed. The electrochemical display element according to claim 1, further comprising:
The electrochemical display element according to claim 8, wherein the second insulating film also serves as a partition wall portion that suppresses movement of ions in the electrolytic solution to adjacent pixels.
The second pixel electrode is formed by applying a liquid material and drying it,
The second insulating film so that the non-affinity of the liquid material with respect to the surface of the second insulating film is higher than that of the non-observation side substrate on which the second insulating film is not formed. The electrochemical display element according to claim 8, wherein a surface treatment is performed on at least one of the surface and the non-formed region.
A contact angle of the liquid material with respect to a surface of the second insulating film is 50 ° or more;
The electrochemical display element according to claim 10, wherein a contact angle of the liquid material with respect to the non-formation region is 20 ° or less.
9. The electrochemical display element according to claim 8, wherein in each pixel, the second pixel electrode is formed to have a larger area than the first pixel electrode.
13. The electrochemical display element according to claim 1, wherein the second pixel electrode is made of a porous metal oxide.