JPH0473622A - Electrochromic display device - Google Patents

Abstract

PURPOSE:To allow an increase in area by laminating an electrochromic electrode layer, which is formed by providing a mesh having an electrical conductivity on one surface of an org. color developing layer consisting of a conductive high polymer having an electrochromic characteristic, an electrolyte layer and a counter electrode layer in this order. CONSTITUTION:This device is constituted by respectively laminating a resin substrate 2, the electrochromic electrode layer 3 formed by providing the mesh 1 having the electrical conductivity on one surface of an org. color developing layer 6, the electrolyte layer 4 and the counter electrode 5 in this order. At least either of the resin substrate 2 and the counter electrode 4 is formed transparent. The thickness of the org. color developing layer 6 can be adjusted by changing the concn. of the resin soln. contg. the conductive high polymer and the actual film thickness thereof is preferably about 500 to 2,000Angstrom . The contrast as the display elements is poor if the film thickness of the org. color developing layer 6 is too small. Unequal colors are liable to arise and the response speed decreases if the thickness is too large. The formation of the display device to a larger area is possible in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an electrochromic display device that exhibits a color change due to an electrochemical redox reaction.

(Prior Art) In recent years, electrochromic elements and display devices have attracted attention as new display devices to replace liquid crystal display devices.

Since liquid crystal display devices display images using changes in the amount of liquid crystal, there are limitations in terms of viewing characteristics, brightness, multicolorization, etc. In contrast, with electrochromic devices, the display is clear with no visual dependence compared to liquid crystal display devices, and once a voltage is applied between the electrodes to create an electric field and write, it is then held by the electric liver. It is seen as a promising future display device because it has a memory function that allows the display to continue even if it is not used.

At present, electrochromic elements can be roughly divided into two types: those whose coloring layers are formed from inorganic materials and those whose coloring layers are formed from organic materials. The former is mainly wO3, M2O3, M2
A thin film of a transition metal such as O5 is used, and a solution type using an electrolyte aqueous solution or an R-containing electrolyte is generally used. As the latter organic substance, phthalocyanine, viologen complexes, and conductive polymer materials are being studied.

The discoloration mechanism of elements using inorganic materials is generally due to changes in light absorption characteristics due to charge transfer of transition metals.

For this reason, the response speed of color change is faster than elements using organic materials, but protons are often involved in charge transfer reactions, which tends to cause electrode deterioration. Furthermore, the color tone is poorer than elements using organic substances.

In an element using an organic substance as a coloring layer, for example,
When using phthalocyanine, etc., it is possible to form a coloring layer by vapor deposition on the substrate, but it is difficult to form a coloring layer with the electrode!
There is a problem with adhesion, which causes deterioration and color unevenness. On the other hand, when a conductive polymer is used, it has the advantage that it is easy to form a film and can have a large area, and various proposals have been made.

For example, JP-A No. 61-238028 proposes the use of films made of botaniline, boppirole, polythiophene, and the like. However, this method using a conductive film has the disadvantage that in order to increase the area of the device, it is necessary to increase the area of the electrode when manufacturing the film by electrolytic polymerization, which increases the size of the equipment. Moreover, when a large electrochromic/reflective display element is produced, the response speed becomes slow, resulting in problems such as a temporal difference in color change.

(Problems to be Solved by the Invention) The present invention has been made in view of the above-mentioned drawbacks, and its purpose is to exhibit a clear color change and to easily increase the area by coating, impregnation, spray coating, etc. The present invention provides an electrochromic display device that has excellent response speed even in a large area and can exhibit uniform color changes.

(Means for Solving the Problems) The electrochromic display device of the present invention has an electrochromic electrode layer formed by providing a conductive mesh on one side of an organic coloring layer made of a conductive polymer having electrochromic properties. , an electrolyte layer and a counter electrode are stacked in this order, thereby achieving the above object.

The electrochromic display device of the present invention will be explained with reference to FIG.

As shown in Figure 1, the electrochromic display device includes a resin substrate 2, an electrochromic electrode layer 3 formed by providing a conductive mesh on one side of an organic coloring layer 6, an electrolyte layer 4, and an opposing layer. The electrodes 5 are laminated in this order.

At least one of the resin substrate 2 and the counter electrode 4 is formed transparent.

The resin substrate 2 has a conductive mesh 1 on its surface.
It is best to attach the material by crimping or laminating, for example, polycarbonate board, polyacrylic board, polyvinyl chloride board, polyethylene board, polypropylene board, etc.
BS plates, polystyrene plates, etc. are preferably used.

The conductive membrane L1 used in the present invention is usually made of conductive fibers, and examples of the conductive fibers include conductive metal fibers, carbon fibers, and organic fibers, such as platinum fibers, Examples include fiber, silver fiber, copper fiber, carbon fiber, etc. The conductive mesh 1 may be formed only from these conductive fibers (for example, metal fibers), or may be formed from conductive fibers and non-conductive fibers (for example, organic polymer fibers). It's okay.

Further, the conductive mesh 1 may be formed by laminating a plurality of meshes, or may be formed by punching out a conductive metal foil to form a conductive mesh.

When the conductive mesh 1 is made of conductive fibers,
The diameter of the conductive fibers is preferably about 20 to 60 μm. 2
If the fiber is less than 0 μm, it will be difficult to process the fiber itself, and if the fiber is less than 60 μm
If it exceeds m, the transparency of the electrochromic display device will be lost, which is not preferable. Further, the mesh spacing of the conductive mesh 1 is preferably about 30 to 200 mesh. If the mesh is too fine, the transparency will be reduced, and if the mesh is too coarse, the processing and mesh will be difficult.
It becomes difficult to integrate the organic coloring layer 6 with the organic coloring layer 6. Furthermore, when an electrochromic display device is formed using a conductive mesh 1 made of a certain type of metal fiber, the mesh 1 may be very noticeable due to light reflection, etc.
In this case, use a mesh of paint or dye to control diffuse reflection.
Alternatively, a composite mesh using organic polymer fibers and metal fibers may be used.

To form the electrochromic electrode stone 3,
For example, it can be done as follows.

■ Conductive polymers with electrochromic properties,
A resin solution is prepared by dissolving this material in a solvent that can dissolve it. On the other hand, a conductive mesh board 1 is crimped or laminated on a resin substrate 2 to produce a mesh board 7 as shown in FIG. 3, and this mesh board 7 is impregnated in a bath containing the resin solution. After that, it is pulled up and then dried. To press the resin substrate and the conductive mesh 1 together, press molding, melt adhesion, etc. are used.

(2) The resin solution is applied to the mesh 1 side of the mesh substrate 7 by casting or spin cord, and then dried. For casting, you can use various applicators, brushes, spatulas, etc. For spin cords,
A spin coater may be used.

(2) The above resin solution is spray-coated on the mesh/uni side of the mesh substrate 7 using a coating device such as a spray gun, and then dried.

In either method, the conductive mesh 1 must not be completely buried in the resin substrate 2, and as shown in FIG. There is a point.

In the mesh substrate 7, in order to further improve the conductivity, a tin oxide (5nQ) film, an indium oxide film, a tin oxide (tin oxide) film, an indium oxide film, a tin oxide film, etc.
A conductive thin film such as an ITo) film may be provided by a method such as vapor deposition or sputtering.

As conductive polymers having the above-mentioned electrochromic properties, polymers that are soluble in various solvents are generally used.
In particular, acetylene polymers mainly composed of structural units represented by the general formula (I) are preferred, where R1, R2, and R3 are
Each independently represents hydrogen, an alkyl group having 10 or less carbon atoms, a trifluoromethyl group, or a trialkylnoryl group (
The alkyl group represents a carbon number of 6 or less, and may be the same or different.

Such acetylene polymers include, for example, bo')(o-to')methylciwarphenyl)acetylene,
Polyphenylacetylene, bois(o-S')fluoromethylphenyl)acetylene, hozo(0-methylphenyl)acetylene, poly(p-t-butylphenyl)acetylene, poly(2,6-cymethyl-4-butylphenyl) ) Acetylene, etc.

Further, as other conductive polymers, for example, polyaniline, polythiophene, polypyrrole, poly(0-dialkoxy/benzene), etc. can also be used.

The thickness of the organic coloring layer 6 can be adjusted by changing the concentration of the resin solution containing the conductive polymer, and the actual film thickness is preferably 300 to 3,500 layers, preferably 500 to 2,000 layers. That's about it. If the film thickness of the organic coloring layer 6 is too small, the contrast as a display element will be poor, and if it is too large, color unevenness tends to occur (and the response speed tends to decrease).

The counter electrode 5 used in the present invention can be any conventionally known electrode, such as a tin oxide (Sn○) film, an indium oxide-tin oxide (ITO) film, a metal plate, an amorphous tungsten oxide iron complex, Examples include transition metal oxide carbon sintered bodies, manganese oxide, and the like.

The electrolyte layer 4 used in the present invention may be in a solid phase or a liquid phase, and examples thereof include the following.

■Inorganic dielectric thin films such as tantalum oxide, niobium oxide, and titanium oxide.

■After dissolving an electrolyte such as lithium perchlorate, tetraethylammonium borofluoride, or lithium iodide and a resin component such as polyvinyl alcohol, polyvinyl butyral, or polyethylene ogyuride in a solvent that can dissolve both, the solvent is removed. Polyelectrolyte obtained by.

■A liquid-phase electrolyte made by dissolving the electrolyte obtained in step (■) above in an organic solvent such as acetonitrile, nitromethane, or propylene carbonate.

(Function) In the electrochromic display device of the present invention, an electrochromic electrode layer (an organic coloring layer, an electrolyte layer, and a counter electrode are laminated in this order, and an electrode interface is formed at the interface between the organic coloring layer and the electrolyte layer. It has a structure in which ions can freely enter and exit as charges move in the organic coloring layer.The ingress and egress of ions causes a color change in the organic coloring layer.

Here, by forming an electrochromic electrode layer by providing a conductive layer on one side of the organic coloring layer,
The coloring reaction of the organic coloring layer occurs more quickly, and as a result, an electrochromic display device with excellent response speed can be obtained. In addition, to create an electrochromic electrode layer, it is not necessary to use a film made of conductive polymer.
As described above, since the resin solution of the conductive polymer can be applied or impregnated onto the resin substrate provided with the conductive mesh, it is easy to create a large-area electrode layer.

【Example) The present invention will be explained in more detail with reference to Examples below.

Commercially available hard polyvinyl chloride board (3mm x 200a+m
A plastic electrode with a metal mesh adhered to the surface was prepared by press-molding (185° C. for 14 minutes) conductive gold menonyu on the surface (185° C., 14 minutes).

Next, a solution of poly(o-trimethylnrylphenyl)acetylene (:!!!!!!!! average molecular fi 1.9 million Jog dissolved in 650 cc of toluene) was spin-coded onto the mesh side of the plastic electrode and dried to develop an organic color. formed a layer.

90g of lithium perchlorate and 30g of polyethylene oxide
g, acetonitrile 150cc and ion exchange water L5
A polymer electrolyte solution was prepared by dissolving it in a mixed solvent of Qcc. This solution was applied on the vapor deposition surface (opposing T1 pole) of the polyethylene terephthalate film on which indium oxide-tin oxide was vapor-deposited, and then
Vacuum drying was performed at 0''C for 5 hours to prepare an electrolyte layer.

An electrochromic display device was obtained by overlapping the plastic electrode and the counter electrode so that the organic coloring layer and the electrolyte layer were in contact with each other.

When a voltage of about 2.5 V was applied between the two electrodes, with the metal mesh side of this display device as an anode and the opposite electrode side as a cathode, the organic coloring layer changed from reddish-purple to colorless. Next, -2,
When a voltage of 5V was applied between both electrodes, the organic coloring layer changed from colorless to reddish-purple. The above color change required approximately 1.0 seconds for the reaction from reddish-purple to colorless, and approximately 0.5 seconds for the reverse reaction.

Next, when a voltage between 2.0'/ and -1.5V was repeatedly applied, no abnormality was observed in the color change even after 1000 repetitions.

Lk dish poly(0-trimethylnrylphenyl) acetylene (weight average molecule m1.9 million) 10g to toluene 650cc
A transparent electrode vapor deposition layer (200 mm x 200
mm) and dried to form an organic coloring layer.

90g of lithium perchlorate and 30g of polyethylene oxide
g, acetonitrile 150cc and ion exchange water 1
A polymer electrolyte M solution was prepared by dissolving it in 50 cc of a mixed solvent. This solution was applied onto the vaporized side (counter electrode) of a polyethylene terephthalate film on which indium oxide-tin Mide was vapor-deposited, and heated at 150'C for 4 hours, and then heated to 80°C for 4 hours.
The electrolyte layer was prepared by vacuum drying at °C for 5 hours.

The above-mentioned transparent electrode and the above-mentioned counter electrode are placed together so that the organic coloring layer and the electrolyte layer are in contact with each other.
A display device was obtained.

The transparent electrode side of this display device is used as an anode, and the opposite electrode side is used as a cathode, and the distance between the two electrodes is about 2. When a voltage of OV was applied, the organic coloring layer changed from reddish-purple to colorless.

In this case, since there is a time difference in color change, it took 10 seconds or more to completely change the color of the entire surface. Next, when a voltage of -1.5V was applied between both electrodes, the color changed from colorless to reddish-purple. The time required for this color change was 108
It was 1 or more.

(Effects of the Invention) Since the structure of the electrochromic display device of the present invention is as described above, it exhibits clear color changes depending on the difference in applied voltage, has fast response even if the area is large, and does not require large equipment. A large-area display device can be manufactured without the need for

Furthermore, by selecting a transparent material for the counter electrode, the transparency when colorless is not impaired.

Figure 1 is a sectional view showing an embodiment of the electrochromic display device of the present invention, Figure 2 is an enlarged sectional view of the main part of the device shown in Figure 1, and Figure 3 is a diagram showing a mesh substrate. It is an enlarged sectional view.

l... Conductive mesh, 2... Resin substrate, 3...
Electrochromic electrode stone, 4... Electrolyte layer, 5.
...Counter electrode, 6...Organic coloring layer.

that's all

Claims (1)

[Claims] (1) An electrochromic electrode layer formed by providing a conductive mesh on one side of an organic coloring layer made of a conductive polymer having electrochromic properties, an electrolyte layer, and a counter electrode are laminated in this order. An electrochromic display device featuring: