JPS6070419A - Production of electrocoloring display element - Google Patents

Abstract

PURPOSE:To perform uniformly coloration and discoloration by improving the adhesion between an EC material layer and a solid ion conductive material layer by using an ion conductive paint obtd. by dispersing a pigment different from the electrifying polarity of an electrochromic material in a high polymer soln. CONSTITUTION:A transparent substrate 5 consisting of glass, etc. is used and a thin film of an electrochromic material layer 2 is provided on a display segment electrode 1 by vapor deposition, sputtering, plating, coating, etc. An ion conductive paint obtd. by dispersing fine particles of a pigment having a positive electrifying polarity in the case of using an electrochromic material having a negative electrifying polarity into an aq. high polymer soln. contg. halide of an alkali metal and electrolyte such as various perchlorates is coated on the electrochromic material layer and is dried to provide an ion conductive material layer 3. An electrode 4 facing the electrode 1 is provided in a thin layer on said layer by vapor deposition, sputtering, etc. The ununiformity in the coloring and decoloring density in the respective display segment electrodes is eliminated by the above- mentioned constitution.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical field to which the invention pertains] The present invention relates to an electrochromic display element that utilizes electrochromic phenomena, and particularly relates to an electrochromic display element that utilizes an electrochromic phenomenon, and particularly relates to an electrochromic display element that utilizes an electrochromic phenomenon. This invention relates to improvements in electrochromic display elements having conductive material layers.

[Prior art and its problems]

The phenomenon in which the light absorption spectrum of a substance changes or the generation and disappearance of colored species occurs reversibly due to an electric field or electric current is called an electrochromic phenomenon. (abbreviated as ECD) is being researched into practical use, but its lifespan for repeating color development and fading is short compared to other display elements using liquid crystals or light emitting diodes, and it is difficult to emit light. The problem was that decoloring was uneven.

For example, WO3 and MoO3, which become colored when reduced, Ir03, which becomes colored when oxidized; Phthalone N-anine, its um form, and tetrathiofulvalene compound dyes are used as ``electrochromic honeyeater'' thorns (jib).
Any of the electrochromic materials that have been developed above must be colored in proportion to the charge (i4. It was impossible to erase the color.

That is, as shown in FIG. 1, in order to display numbers using the electrochromic phenomenon, a large number of display segment electrodes 11 with different areas and shapes are required. '12.13
...17 is required, but the density of the 1/2 reduction current flowing to each display segment electrode and the counter electrode 3 [l] differs depending on the area and shape of the display segment polarization, and It is impossible to uniformly oxidize or reduce the electrochromic material by keeping the redox current density constant between the display segment electrode and the counter electrode due to leakage current to the electrodes.

For this purpose, in the case of an FD using a liquid ion conductive layer, multiple auxiliary electrodes are provided near the display segment electrode, and the electrochromic abrasive layer is oxidized or reduced between the display segment electrode and the auxiliary electrode. By switching the coloring/decoloring signal current applied to each display segment electrode using a field-effect transistor at t, it is possible to exchange a certain amount of charge necessary for Improvements have been made to ECD drive electrical circuits, such as preventing leakage current.

However, in ECDs using solid ion conductive materials, the adhesion between the electrochromic material layer provided on the display segment electrodes and the ion conductive material layer provided in contact therewith has not been sufficiently improved. , the electrical resistance between the display segment electrode and the counter electrode differs for each display segment electrode, and it is difficult to solve the non-uniformity of color development and fading even with an improved ECD drive electric circuit.
It was IM1.

[Object of the present invention]

An object of the present invention is to provide an ECD that uniformly develops and fades color by improving the adhesion between the electrochromic particle υ and the solid ion conductive material layer.

Further, the second object of the present invention is to uniformly develop and fade color, thereby achieving 1! ;Practical use of CD; 4It is to extend one's life.

[Summary of the invention]

In the present invention, a reversible redox reaction occurs electrochemically,
In addition, a so-called electrochromic particle whose light absorption spectrum differs depending on the oxidation state and the original state is provided in the form of a thin film on the transparent display segment electrode, so that the band's absorption in the polymer solution containing the electrolyte is reduced. An ion conductive layer is formed by applying and drying an ion conductive paint obtained by dispersing a pigment in the polymer solution, which has a polarity different from that of the electrochromic material, onto a thin film of the electrochromic material, and then, A counter electrode is provided on this ion conductive layer by vacuum evaporation or the like.

Specifically, as shown in FIG. 2, a transparent substrate 5 made of glass or the like on which display segment electrodes 1 are provided in advance is used.
Electrochromic material layer 2 on display segment electrode 1
is formed into a thin film using known methods such as vapor deposition, sputtering, plating, and coating, and then the polymer aqueous solution is added to a polymer aqueous solution containing an electrolyte such as an alkali metal halide or various perchlorates. When using electrochromic feathers whose charge polarity is negative in the polymer aqueous solution, pigment particles whose charge polarity in the polymer aqueous solution is positive are dispersed in the polymer aqueous solution to obtain an ion conductive paint. Apply and dry the ion conductive material layer 3 on the electrochromic material layer.
In the present invention, a metal is provided on the ion conductive material layer 3 in a thin layer facing the display segment electrode 1 by a commonly used method such as vacuum evaporation or sputtering.

The pigment used in the present invention is ']"i0z+5iO
z+MgO, MnO2, A/203. Examples include ZnO, ThO, etc., and are appropriately selected depending on the charging polarity of the electrochromic material in a polymer solution containing an electrolyte.

For example, electrochromic materials such as w03 and Al1
O03 is 9 in an aqueous solution of i-formed molecules containing an electrolyte with a pH of around 7, and a polarity of 41? Since the particles are electrically charged, Al2O3 fine particles, which are positively charged in the polymer aqueous solution, are used as the t-term material.

The 'l''ioz fine particles are negatively charged in the water bath liquid near PI: (, 7, but the surface of the TiO2 fine particles is Al2O
1i02, as noted by nfJ, because the particles with a slight black mark in 3 are positively charged.

Sjo 2 +MnO2+ All 203+ Z n
Pigments such as Oy ThO+N1g0 may be used individually, or the surface may be covered with other compounds for the purpose of changing the charge polarity.

Further journal op colloid interface
Science (Journal of Co#aidIn
surface 5science) Vo122,40
As is known from the f17i text on page 4, for example, TiO2
Since the sign of charge changes depending on the type of solvent, it goes without saying that the purpose of the present invention can be achieved even if a solvent for a polymer solution containing an electrolyte is selected so that the charge of the electrochromic material and the pigment are of opposite polarity. Nor.

〔Effect of the invention〕

As described above, the electrochromic material provided in advance on the display segment electrodes and the pigment particles dispersed in advance in the polymer solution containing an electrolyte have opposite charge polarities in the polymer solution. Therefore, the polymer solution containing the electrolyte and pigment applied to the electrochromic material layer is uniformly adhered to the surface of the electrochromic material, and when dried, forms an ion-conductive film with a uniform thickness on the surface of the electrochromic material. Can be done. Therefore, the volume resistivity between the counter electrode and the display electrode provided on the surface of the formed ion conductive film becomes uniform in all parts, and the volume resistivity between the counter electrode and the display electrode, as pointed out in the problem of the prior art, Non-uniformity in current density is eliminated, and non-uniformity in developing and fading color density does not occur in each display segment electrode. At the same time, since the redox 1 (i) current is not locally concentrated, local deterioration of the electrochromic material does not occur and the life of the display device is improved.

Since the fine pigment particles are evenly stuck on the electrochromic electrodes (7j), the background color of each exposed segment electrode is also uniform.

[Embodiments of the invention]

Example 1 A Nesa membrane with a sheet resistance of 50 Ω was applied to a glass plate with a thickness of 1 mm! /) The previously provided tS16 conductive glass plate is etched to form the numeric display talk of the Wasegment, and then II/[ as an electrochromic material layer is etched.
003 was deposited using a sputtering device. Deposited MO
The thickness of O3 was: 3000X.

On the other hand, polyvinyl alcohol ("pIj degree 24 (10
100 g of 10% by weight water bath solution with a degree of 90%
The surface of TiO2 was coated with 5 iOz in a liquid prepared by mixing and dissolving 6 g of polyethylene glycol (intensity 400), LiClO40,2mo7, and TiO2
30 g of white pigment coated with M2O3 equivalent to 2% by weight of (Teikoku Kagaku Kogyo, product name JR602)
were mixed and dispersed using an agate mortar to obtain a white ion conductive paint.

The obtained ion conductive coating material was flow-coated onto a glass plate onto which the MoO3 was sputtered, and then dried in a dryer at 70''C for 3 hours.

Thereafter, a counter electrode was provided by vacuum-depositing gold on the ion-conductive coating surface, and the ion-conductive layer was made into a solid, so-called all-solid D. -0 to 7 segment' electrodes
, 7 volts was applied, within 0.5 seconds JvToOa on all segment electrodes was oxidized and colored blue, and a pattern showing the number 8 clearly appeared on the white background. It was confirmed that the blue characters that appeared remained as they were even if the voltage application was stopped, and that they had memory properties.
．． When a voltage of 5 volts was applied, the blue characters disappeared and the entire display surface of the ECD returned to its initial state of uniform white color. The voltage applied to each display segment electrode is +0.7 volts 0.5 seconds -0, with the voltage of the counter electrode as a reference.
ECD at 5 volts 0.5 seconds repetition frequency 0.5 Hz
When the practical life of the display was measured, no color unevenness occurred between the seven display segment electrodes even after repeating color development and fading more than 104 times.

On the other hand, 'ri02 is a white pigment whose surface is not coated with Al2O3 (manufactured by Ishihara Sangyo Co., Ltd., product number A-
In the ECD manufactured by coating an ion conductive paint with the same composition as in this example, except that 100) was used, the electrostatic repulsive force between the 1003N film and the pigment fine particles was evaporated on the glass substrate. However, it is difficult to obtain an ion-conducting layer with a uniform thickness, and each display segment)
MoO deposited on the display segment by applying a voltage of 107 volts for 0.5 seconds between the JL pole and the counter electrode
3 was excessively reduced, uneven color development occurred even within the single segment electrode, and the display element no longer functioned.

Example 2 A transparent conductive glass plate with a thickness of 1 mm on which a NESA film with a sheet resistance of 50 Ω was previously provided was etched to form a 7-segment numeric display electrode, and then an electrochromic material was etched. A vJO3 thin film was formed by depositing WO2 as a layer using the sppack method. The thickness of the deposited three concave layers was aoooX.

On the other hand, 2.5 g of polymethyl methacrylate and LiCI
O45g s polyethylene glycol - 1.5g 50
TiO2 in a liquid dissolved in g of methyl isobutyl ketone
The surface of is coated with 5iOz, which corresponds to 10 cents by weight, and A/2, which corresponds to 2 cents by weight of TiO2.
White pigment coated with 03 (manufactured by Teikoku Kako Co., Ltd., product name: J
A white ion conductive paint was obtained by adding 5 g of R602) and mixing and dispersing using an agate mortar.

The obtained ion conductive coating material was flow-coated onto the glass plate on which the W03 was deposited, and then dried in a dryer at 100° C. for about 3 hours.

Thereafter, gold was vacuum-deposited on the ion conductive coated surface to provide a counter electrode, thereby producing a so-called all-solid ECD in which the ion conductive layer was solid.

The display surface of the obtained full-screen ECD is milky white when no display signal voltage is applied, and the display segment's -
When 1.3 volts are applied, the color develops into pale blue within 0.5 seconds, and when +1.3 volts is applied, the color returns to milky white.

When we measured the practical life by applying a voltage of +1.3 volts and a voltage of -113 volts alternately for 0.5 seconds each between the display segment electrode and the opposing 'g electrode, we found that coloring and fading occurred more than 105 times. Even after repeating the display for 11 times, there was no difference in the degree of coloring/decoloring among the seven display segment electrodes.

On the other hand, a white ion conductive paint having the same composition as in this example was used, except that a white pigment (manufactured by Ishihara Sangyo Co., Ltd., product number A100) was used that did not coat the surface of TiO2. The obtained all-solid-state ECD had uneven milky white color on the display surface, and uneven color development and fading occurred even within the single segment electrode.

Although the present example has been explained using an inorganic electrochromic material, similar results have been obtained with an organic electrochromic material.

[Brief explanation of the drawing]

FIG. 1 is a perspective view schematically showing an all-solid-state ECD, and FIG. 2 is a schematic cross-sectional view of the all-solid-state ECD. t, 11. t2; ta...17...To display segment cage, 2...Electrochromic material ttV I
iW, 3...Solid electrolyte (ion 4 t+4 material layer)
, 4... Opposing kick pole, 5... Transparent substrate (glass). Agent Patent Attorney Rule Chika 7i Takaj (e-Yoka 1 person) Figure 1 Figure 2 Continuation of Figure 1 page 1

Claims (5)

[Claims] (1) A first step in which a thin film of an electrochromic material is closely attached to a transparent electrode for display, and the charge polarity in a polymer solution containing an electrolyte is determined by the band of the electrochromic material.
- A second step of obtaining an ion-conductive paint by dispersing pigments of polarity and opposite polarity in a polymer solution containing an electrolyte, and applying and drying the obtained ion-conductivity paint onto a thin film of electrochromic material. Third step and applied and dried ion 4
A method for manufacturing an electrochromic display element, characterized in that a fourth step of providing a conductive electrode on the conductive material layer is performed. (2) A method for producing an electrochromic display element according to claim 1, characterized in that water is used as a solvent and a water-soluble polymer compound is used as a carrier for the pigment and electrolyte. (3) When using an electrochromic material whose charge polarity in an aqueous polymer solution containing an electrolyte is negative, the isoelectric point of the aqueous polymer solution containing an electrolyte is P, H
2. Production of an electrochromic display element according to claim 2, characterized in that the ionically conductive layer is formed using a paint in which a pigment having a higher concentration than Method. (4) Charge polarity in a polymer aqueous solution containing an electrolyte is
In addition to using electrochromic applications with positive polarity, isoelectric points are used. p of a polymer aqueous solution containing solutes
Claim 2, characterized in that the ion ξ is formed into a charge layer by using a phase conductor in which a pigment lower than H is dispersed in a polymer aqueous solution containing 1+1. A method of manufacturing the electrochromic display element described above. (5) By adding +M += to the surface Eni of the gold fluoride particles that serve as the nucleus, the equal '4 point of the particle is set as the nucleus, and the point differs from the point where the metal rI<the compound particle equal 1. Claims ``i'y Item 3 and 07i!:
B. A method for manufacturing an electrochromic display element according to 4-phase. (The surface of the 61TiO2 fine particles is coated with 5iOz, and the isoelectric point is set to 5 or less by coating the four sides of the Ti0z fine particles with a pigment or at least one kind of metal oxide to make the isoelectric point 7 or less.
Claim 5, characterized in that the above-mentioned pigment is dispersed in a polymer solution containing an electrolyte to obtain an ion-exclusive paint, and this paint is used to form an ion barrel electric material. A method for producing an electrochromic display element as described in 2.