JP2011017873A - Electrochromic display device and driving method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrochromic display device which can generate optional colors by simple control.SOLUTION: The display device includes a display substrate 11, a facing substrate 12, electrochromic layers 14a and 14b pinched between the display substrate 11 and the facing substrate 12, and an electrolyte 20. The electrochromic layers 14a and 14b include electrochromic compounds 16a and 16b which stick to a semiconductor material 17 which has a nano-structure, and generate colors by irradiating light of a wavelength, which is absorbed by the electrochromic layers 14a and 14b.

Description

  The present invention relates to an electrochromic display device and a driving method thereof, and more particularly, to an electrochromic display device capable of independent multicolor display and a driving method thereof.

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

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

  On the other hand, as a promising technique for realizing a reflective display device without providing the color filter as described above, there is a method using an electrochromic phenomenon.

  A phenomenon in which a redox reaction occurs reversibly and a color changes reversibly by applying a voltage is called electrochromism. An electrochromic display device is a display device that utilizes the coloring / decoloring (hereinafter referred to as color erasing) of an electrochromic compound that causes this electrochromic phenomenon. Since this electrochromic display device is a reflective display device, has a memory effect, and can be driven at a low voltage, it is a leading candidate for display device technology for electronic paper use, from material development to device design. R & D has been conducted extensively.

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

  On the other hand, the electrochromic display device is expected as a multicolor display device because various colors can be developed depending on the structure of the electrochromic compound.

  There are some known examples of multicolor display devices using such electrochromic display devices. For example, Patent Document 2 discloses a multicolor display device using an electrochromic compound in which fine particles of a plurality of types of electrochromic compounds are stacked. This document describes an example of a multicolor display device in which a plurality of electrochromic compounds, which are polymer compounds having a plurality of functional functional groups with different voltages exhibiting color development, are laminated to form a multicolor display electrochromic compound. .

  Further, Patent Document 3 discloses a display device in which a plurality of electrochromic layers are formed on an electrode, and multiple colors are developed using a difference in voltage value or current value necessary for the color development. In this document, an example of a multicolor display device having a display layer that is formed by laminating or mixing a plurality of electrochromic compounds that develop different colors and have different threshold voltages for color development and different charge amounts necessary for color development. Is described.

  Further, Patent Document 4 describes an example of a multicolor display device in which a plurality of structural units each having an electrochromic layer and an electrolyte sandwiched between a pair of transparent electrodes are stacked. Further, Patent Document 5 describes an example of a multicolor display device corresponding to RGB three colors by forming a passive matrix panel and an active matrix panel using the structural units described in Patent Document 4.

  Further, as electronic paper, so-called rewritable paper in which a drive unit is separated from a display unit has been developed and put into practical use. Although rewritable paper requires a separate rewriting device that writes to rewritable paper like a printer, the media is lighter and less expensive than ordinary electronic paper with a drive unit integrated with the display unit. This is advantageous in applications where the frequency of rewriting is low. Development of rewritable paper is progressing by the thermal method and the display method of cholesteric liquid crystal, and a part is put into practical use.

  In Patent Documents 6 and 7, in the electrochromic method described above, a photoconductor layer in which carriers are generated only in a region irradiated with light to generate conductivity is formed between the electrode and the electrochromic material, An example is described in which only a portion irradiated with light is emitted and light-emitted by simultaneously applying a voltage or a current to the light. Patent Document 6 also describes an example of a multicolor display device in which a plurality of unit structures are stacked.

  However, a multicolor display device using an electrochromic display device has the following problems.

  According to the method disclosed in Patent Document 2, each of the laminated electrochromic compounds is a compound that develops a different color at a different voltage, and therefore it is possible to develop a color by controlling the voltage. However, there is a problem that a plurality of colors cannot be developed simultaneously.

  In addition, since the method disclosed in Patent Document 3 has a plurality of types of electrochromic compounds that develop different colors, a plurality of colors can be developed simultaneously, but any color can be selectively developed. Therefore, there is a problem that complicated voltage / current control is required.

  In addition, the methods disclosed in Patent Documents 4, 5, and 6 require a pair of transparent electrodes to develop a color of one electrochromic layer. There is a problem that the number increases and the reflectance and contrast decrease.

  In addition, the methods disclosed in Patent Documents 6 and 7 have a problem that it is necessary to control voltage and current in a complicated manner at the same time when light is irradiated.

  The present invention has been made in view of the above points, and an object of the present invention is to provide an electrochromic display device capable of developing an arbitrary color with simple control.

  The invention according to claim 1 is an electrochromic display device comprising a display substrate, a counter substrate, an electrochromic layer and an electrolyte provided so as to be sandwiched between the display substrate and the counter substrate. The layer includes an electrochromic compound adsorbed on a semiconductor material having a nanostructure, and is colored by irradiating light having a wavelength that is absorbed by the electrochromic layer.

  According to a second aspect of the present invention, in the electrochromic display device according to the first aspect, the display electrode provided in contact with the electrochromic layer between the display substrate and the electrochromic layer, and the counter electrode It has a counter electrode provided between a board | substrate and the said electrochromic layer, It is characterized by the above-mentioned.

  According to a third aspect of the present invention, in the electrochromic display device according to the second aspect, a plurality of the display electrodes are provided separately from each other between the display substrate and the counter electrode, and the plurality of the display The plurality of electrochromic layers are provided corresponding to each of the electrodes, and an electrical resistance between the one display electrode and the other display electrode is larger than an electrical resistance of the one display electrode. Features.

  According to a fourth aspect of the present invention, in the electrochromic display device according to the third aspect, the plurality of electrochromic layers are colored in different colors.

  According to a fifth aspect of the present invention, in the electrochromic display device according to the third or fourth aspect, the plurality of electrochromic layers have different color development sensitivities with respect to the intensity or wavelength of light to be irradiated. It is characterized by.

  The invention according to claim 6 is the electrochromic display device according to any one of claims 2 to 5, wherein the display electrode is a transparent electrode.

  According to a seventh aspect of the present invention, in the electrochromic display device according to the sixth aspect, the display electrode provided between the display electrode closest to the display substrate and the counter electrode is in contact with the electrolyte. It is characterized by having permeability.

  The invention according to claim 8 is the electrochromic display device according to any one of claims 2 to 7, wherein the plurality of display electrodes are insulated from each other between the plurality of display electrodes. An insulating layer is provided.

  According to a ninth aspect of the present invention, in the electrochromic display device according to the eighth aspect, the insulating layer is permeable to an electrolyte.

  According to a tenth aspect of the present invention, in the electrochromic display device according to the eighth or ninth aspect, the insulating layer includes a polymer that functions as an electrolyte.

  An eleventh aspect of the present invention is the electrochromic display device according to any one of the second to tenth aspects, wherein the electrochromic layer and the counter electrode are opposite to each other or opposite to the counter electrode of the counter substrate. It has a reflective layer on the side.

  The invention according to claim 12 is the electrochromic display device according to any one of claims 2 to 11, wherein the semiconductor material having the nanostructure includes titanium oxide particles, and the electrochromic compound has the following general formula: It includes a dipyridine organic material represented by (1).

（式中、Ｒ１、Ｒ２は、それぞれ独立に置換基を有しても良い炭素数１から４のアルキル基、又はアリール基を表し、Ｒ１又はＲ２の少なくとも一方は、ＣＯＯＨ、ＰＯ（ＯＨ）_２、Ｓｉ（ＯＣ_ｋＨ_２ｋ＋１）_３から選ばれるひとつの基を有する。Ｘは１価のアニオンを表す。ｎは０、１又は２を表す。Ａは、置換基を有しても良い炭素数１から２０のアルキル基、アリール基、複素環基を表す。）
請求項１３に記載の発明は、請求項２から請求項１２のいずれかに記載のエレクトロクロミック表示装置の駆動方法であって、発色した前記エレクトロクロミック層を消色駆動する駆動電圧を、前記エレクトロクロミック層に接する前記表示電極と前記対向電極との間に印加することにより、前記エレクトロクロミック層を消色させることを特徴とする。

(Wherein R1 and R2 each independently represents an alkyl group having 1 to 4 carbon atoms which may have a substituent or an aryl group, and at least one of R1 and R2 is COOH, PO (OH) _2. , Si (OC _k H _{2k + 1} ) having one group selected from _3. X represents a monovalent anion, n represents 0, 1 or 2. A represents the carbon number that may have a substituent. 1 to 20 alkyl groups, aryl groups and heterocyclic groups are represented.)
According to a thirteenth aspect of the present invention, there is provided a method for driving an electrochromic display device according to any one of the second to twelfth aspects, wherein the electrochromic layer that has been colored is driven to be decolored. The electrochromic layer is decolored by applying between the display electrode in contact with the chromic layer and the counter electrode.

  According to a fourteenth aspect of the present invention, in the driving method of the electrochromic display device according to the thirteenth aspect, the driving is performed such that the display electrode in contact with the one electrochromic layer and the counter electrode are decolored. In addition to applying a voltage and insulating the other display electrode from the counter electrode, only the one electrochromic layer is decolored.

  The invention according to claim 15 is the driving method of the electrochromic display device according to claim 5, wherein the one of the electrochromic layers is irradiated with light having an intensity or wavelength that causes only the electrochromic layer to develop color. Only the electrochromic layer is colored.

  The invention according to claim 16 is the driving method of the electrochromic display device according to claim 5, wherein one of the electrochromic layers is irradiated with light having an intensity or wavelength that causes the electrochromic layer to develop a color, and the other electrochromic display device. Only the one electrochromic layer is colored by applying a driving voltage for decoloring driving between the display electrode in contact with the layer and the counter electrode.

  The invention according to claim 17 is the driving method of the electrochromic display device according to any one of claims 1 to 12, wherein the intensity of the irradiation light or the irradiation time is controlled stepwise. Thus, an intermediate color is developed on the electrochromic layer.

  According to the present invention, it is possible to provide an electrochromic display device capable of developing an arbitrary color with simple control.

It is sectional drawing which shows typically the structure of the electrochromic display apparatus which concerns on the 1st Embodiment of this invention. 1 is a perspective view schematically showing a configuration of a display substrate in an electrochromic display device according to a first embodiment of the present invention. It is sectional drawing which shows typically the structure of the electrochromic display apparatus which concerns on the modification of the 1st Embodiment of this invention. It is sectional drawing which shows typically the structure of the electrochromic display apparatus which concerns on the 2nd Embodiment of this invention. 6 is a graph showing a light transmission spectrum measurement result in Example 1. 6 is a graph showing a light transmission spectrum measurement result in Example 3.

Next, a mode for carrying out the present invention will be described with reference to the drawings.
(First embodiment)
An electrochromic display device according to a first embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is a cross-sectional view schematically showing a configuration of an electrochromic display device 10 according to the present embodiment. FIG. 2 is a perspective view schematically showing the configuration of the display substrate 11 in the electrochromic display device 10 shown in FIG.

  However, FIGS. 1 and 2 show an example of the electrochromic display device according to the present embodiment, and the electrochromic display device according to the present embodiment is not limited to the configuration of FIGS. 1 and 2.

  First, the configuration of the electrochromic display device 10 will be described.

  As shown in FIG. 1, the electrochromic display device 10 according to the present embodiment includes a display unit 1 and a light irradiation unit 2. The display unit 1 includes a display substrate 11, a counter substrate 12 provided so as to face the display substrate 11, and a cell 19 in which the display substrate 11 and the counter substrate 12 are bonded to each other through a spacer 18.

  The light irradiation unit 2 is provided independently of the display unit 1, and includes a light irradiation amount control unit 23 including a power supply unit, and an irradiation head 25 including a LED driver 24 and a lens connected to the light irradiation amount control unit 23. It becomes more. The light irradiation unit 2 is provided on the display substrate 11 side of the display unit 1 and irradiates LED light from the display substrate 11 side of the display unit 1.

  As light irradiated from the light irradiation unit 2, laser light, xenon lamp light, deuterium lamp light, halogen lamp light, or the like can be used in addition to LED light. The wavelength of the light to be irradiated is desirably outside the visible range where visibility is low. This is because, when the wavelength of light absorbed by the electrochromic layer is in the visible range, coloring tends to occur even in a decolored state, and visibility may be reduced. In particular, a preferable wavelength range is 250 nm to 450 nm. If the wavelength of the light to be irradiated is 250 nm or less, the light color efficiency is likely to be lowered due to light absorption by the substrate material. If the wavelength of the light to be irradiated is 450 nm or more, it is colored and the irradiation energy is likely to be reduced. Furthermore, it becomes difficult to adapt to the wavelength which the semiconductor material which has the nanostructure mentioned later absorbs light.

  In addition, the electrochromic display apparatus in this invention may use the light irradiation part contained in another apparatus of an electrochromic display device not including a light irradiation part.

  As shown in FIGS. 1 and 2, the display substrate 11 includes a first display electrode 13a formed on the display substrate 11 and a first electrochromic layer 14a provided in contact with the first display electrode 13a. An insulating layer 22 provided in contact with the first electrochromic layer 14a; a second display electrode 13b provided in contact with the insulating layer 22; and a second display electrode 13b provided in contact with the second display electrode 13b. 2 electrochromic layers 14b. The display substrate 11 is a substrate for supporting the above laminated structure.

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

  The first electrochromic layer 14 a is composed of a first electrochromic compound 16 a adsorbed on a semiconductor material 17 having a nanostructure (hereinafter referred to as “nanostructure semiconductor material”). The first electrochromic compound 16a is colored by a reduction reaction due to the photoelectromotive force of the nanostructured semiconductor material 17 generated by light irradiation (hereinafter referred to as “light irradiation”). The nanostructure semiconductor material 17 supports the first electrochromic compound 16a and performs color development and decoloration at high speed.

  In other words, the first electrochromic layer 14a includes the first electrochromic compound 16a adsorbed on the nanostructured semiconductor material 17, and is irradiated with light having a wavelength that the first electrochromic layer 14a absorbs. The first electrochromic compound 16a is oxidized or reduced to develop color.

  In FIG. 1, a configuration in which a single molecule of the electrochromic compound 16a adsorbed to the nanostructured semiconductor material 17 is adsorbed as an ideal state is described, but the electrochromic compound 16a is fixed so as not to move, It is only necessary that electrical connection is ensured so as not to hinder the transfer of electrons accompanying the oxidation-reduction of the chromic compound 16a. Therefore, the electrochromic compound 16a and the nanostructure semiconductor material 17 may be mixed to form a single layer.

  The insulating layer 22 is isolated so that the first display electrode 13a provided with the first electrochromic layer 14a and the second display electrode 13b provided with the second electrochromic layer 14b are insulated. Is to do.

  If the interelectrode resistance between the first display electrode 13a and the second display electrode 13b can be increased, the insulating layer 22 may not be provided, for example, the first electrochromic layer 14a. When the film thickness is increased, the interelectrode resistance between the first display electrode 13a and the second display electrode 13b increases accordingly.

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

  Similar to the first electrochromic layer 14a, the second electrochromic layer 14b includes a second electrochromic compound 16b and a nanostructured semiconductor material 17 that supports the second electrochromic compound 16b. Similar to the first electrochromic compound 16a, the second electrochromic compound 16b is colored by a reduction reaction due to the photovoltaic force of the nanostructured semiconductor material 17 generated by light irradiation. The nanostructure semiconductor material 17 supports the second electrochromic compound 16b and performs color development and decoloration at high speed. The second electrochromic compound 16b develops a color different from that of the first electrochromic compound 16a.

  In other words, the second electrochromic layer 14b includes the second electrochromic compound 16b adsorbed on the nanostructured semiconductor material 17, and is irradiated with light having a wavelength that the second electrochromic layer 14b absorbs light. The second electrochromic compound 16b is oxidized or reduced to develop color.

  The interelectrode resistance between the first display electrode 13a and the second display electrode 13b is to control the potential of one display electrode with respect to the counter electrode 15 independently of the potential of the other display electrode with respect to the counter electrode 15. It is preferable to make the resistance as large as possible. The interelectrode resistance between the first display electrode 13a and the second display electrode 13b is at least larger than the sheet resistance of the display electrode of either the first display electrode 13a or the second display electrode 13b. preferable. When the interelectrode resistance between the first display electrode 13a and the second display electrode 13b is smaller than the sheet resistance of any one of the first display electrode 13a and the second display electrode 13b, When a voltage is applied to one of the display electrodes 13a and the second display electrode 13b, a similar voltage may be applied to the other display electrode. As a result, there is a possibility that the electrochromic layer corresponding to each display electrode cannot be independently developed and decolored. The inter-electrode resistance between the display electrodes is preferably 500 times or more the sheet resistance of each display electrode.

  In order to ensure such good insulation, the interelectrode resistance between the display electrodes can be controlled by changing the thickness of the first electrochromic layer 14a. The thickness of the insulating layer 22 provided in contact with the layer 14a can be changed and controlled.

  The interelectrode resistance between the display electrodes corresponds to the electrical resistance between the one display electrode and the other display electrode in the present invention.

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

  The cell 19 has a structure in which the display substrate 11 and the counter substrate 12 are bonded to each other through a spacer 18. The cell 19 is filled with an electrolyte 20. The electrolyte 20 moves charges as ions between the first display electrode 13a or the second display electrode 13b and the counter electrode 15, and generates the first electrochromic layer 14a or the second electrochromic layer 14b. It is for causing decolorization. This electrolyte is preferably filled between the first display electrode 13 a and the counter electrode 15. Therefore, the second display electrode 13b and the insulating layer 22 formed between the first display electrode 13a and the counter electrode 15 are formed so as to penetrate the electrolyte, that is, have permeability to the electrolyte. . A layer having permeability to the electrolyte can be easily formed on a porous material such as a nanoparticle surface by vacuum film formation.

  Furthermore, by including a polymer having an electrolyte function in the insulating layer, more electrolyte can be filled in the insulating layer, and the reaction rate of color development and decoloration can be further improved. Further, the adhesion strength of the layer can be increased by the polymer.

  The electrolyte 20 can be supported on a polymer. In particular, by using a mixture of a UV curable or thermosetting polymer and an electrolyte, it is possible to easily form an integrated structure by bonding to the display substrate 11 via a spacer and without a spacer.

  That is, to include a polymer that functions as an electrolyte in the present invention includes to include a polymer having an electrolyte function or to carry an electrolyte on the polymer.

  A white reflective layer 21 is provided in the cell 19. The white reflective layer 21 is for improving the white reflectance when the electrochromic display device 10 is used as a reflective display device. The white reflective layer 21 is formed by injecting the electrolyte 20 in which white pigment particles are dispersed into the cell 19. Alternatively, the white reflective layer 21 may be formed by applying a resin in which white pigment particles are dispersed on the counter electrode 15. Alternatively, the white reflective layer 21 may be provided on the opposite side of the counter substrate 12 from the counter electrode 15.

  Next, the operation of multicolor display of the electrochromic display device 10 according to the present embodiment will be described.

  The first electrochromic layer 14a or the second electrochromic layer 14b has different color development sensitivities with respect to the light amount (intensity) or wavelength of light emitted from the LED. In the case of providing a difference in the color development sensitivity, it can be easily set by providing a difference in the light absorption or reduction potential of the electrochromic layer with respect to the light emitted from the LED.

  When the color development sensitivity differs with the amount of light (intensity) of LED light emitted from the LED, the LED emitted from a single LED is combined with selective decoloring (selective decoloring) by an electrode. The electrochromic layer can be selectively colored by light. That is, when the selected electrochromic layer is irradiated with LED light of the amount necessary for color development, and an electrochromic layer with better color development sensitivity than the selected electrochromic layer, the electrochromic with better color development sensitivity Decoloring is performed by applying a decoloring voltage for decoloring driving between the display electrode in contact with the layer and the counter electrode.

  When three or more electrochromic layers are formed, the above-described driving operation is performed in order from the electrochromic layer having the lower sensitivity, and all the electrochromic layers are selectively selected. Can develop color.

  In addition, about the sensitivity difference of the color development sensitivity between each electrochromic layer, a preferable range is 1.1 to 3 times the light quantity (intensity) irradiated with LED light. When the difference in sensitivity is 1.1 times or less, it is difficult to control the irradiation amount, and it becomes difficult to selectively color each electrochromic layer. Further, if the sensitivity difference is three times or more, the absolute amount of the irradiation amount increases, so that the color development sensitivity tends to decrease, and a high-power light source is required.

  On the other hand, when a sensitivity difference with respect to the LED wavelength is set, an arbitrary electrochromic layer can be selectively colored by using different numbers of LED light sources corresponding to the number of electrochromic layers. Alternatively, for example, by using an LED light source including light of a plurality of wavelengths, such as a white LED, the display electrode and the counter electrode that are in contact with the electrochromic layer that does not require color development, as described above with respect to the light amount (intensity) An arbitrary electrochromic layer can be selectively colored by decoloring by applying a decoloring voltage for decoloring driving.

  Further, by controlling the intensity of light to be irradiated or the time to irradiate light continuously to change the reduction amount of the electrochromic compound, an intermediate color can be developed. Furthermore, by using means for controlling the intensity of light to be irradiated or the time for light irradiation in a stepwise manner, it is possible to develop an intermediate color without analog control. That is, it is possible to develop an intermediate color by irradiating light as a light pulse and changing the light intensity value, the pulse width, and the number of times the light pulse is applied.

  In this way, by selectively coloring the electrochromic compound, the color of only the first electrochromic layer 14a, the color of only the second electrochromic layer 14b, the first electrochromic layer 14a and the second electrochromic layer The color of both layers 14b can be changed to three levels of color, and multicolor display is possible.

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

  Further, since the white reflective layer 21 is provided in the cell 19, the white reflectance is high, and the reflectance is reduced due to the stacked first electrochromic layer 14a and second electrochromic layer 14b. This can be supplemented and multi-color display with excellent visibility is possible.

  Further, since the first electrochromic layer 14a and the second electrochromic layer 14b have a structure in which the first electrochromic compound 16a and the second electrochromic compound 16b are supported on the nanostructure semiconductor material 17, respectively, Multicolor display with excellent decoloring response speed is possible. In particular, since the photovoltaic power is directly sent to the electrochromic compound from the electron donating group bonded to the nanostructured semiconductor material 17 or the electrochromic compound by light irradiation, color development can be performed at a higher speed than the conventional method of applying a coloring potential to the electrode. Is possible.

  Next, materials used for the electrochromic display device 10 according to the present embodiment will be described.

  First, the material of each layer formed on the display substrate 11 and the display substrate 11 will be described.

  The material of the display substrate 11 is not particularly limited as long as it is a transparent material, but a substrate such as a glass substrate or a plastic film is used.

The material of the first display electrode 13a and the second display electrode 13b is not particularly limited as long as it is a conductive material. However, since it is necessary to ensure light transmission, it is transparent and conductive. A transparent conductive material having excellent properties is used. Thereby, the visibility of the color to develop can be improved more. As the transparent conductive material, inorganic materials such as tin-doped indium oxide (hereinafter referred to as ITO), fluorine-doped tin oxide (hereinafter referred to as FTO), and antimony-doped tin oxide (hereinafter referred to as ATO) can be used. Among these, indium oxide (hereinafter referred to as In oxide), tin oxide (hereinafter referred to as Sn oxide) or zinc oxide (hereinafter referred to as Zn oxide) formed by vacuum film formation, in particular. An inorganic material including one is preferable. In oxides, Sn oxides, and Zn oxides are materials that can be easily formed by sputtering, and are materials that can provide good transparency and electrical conductivity. Particularly preferable materials are InSnO, GaZnO, SnO, In ₂ O ₃ and ZnO.

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

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

  Among the above, the general formula (1) is particularly preferable.

で表されるジピリジン系化合物を含むことがよい。これらの材料は発消色電位が低いため、複数の表示電極を有するエレクトロクロミック表示装置を構成した場合においても、光照射によりナノ構造半導体材料１７より生じる還元電位により良好な発色の色値を示す。

It is good to contain the dipyridine type compound represented by these. Since these materials have a low color extinction potential, even when an electrochromic display device having a plurality of display electrodes is formed, a color value of good coloring is exhibited by a reduction potential generated from the nanostructured semiconductor material 17 by light irradiation. .

  Furthermore, the dipyridine organic material of the general formula (1) can be reduced in color by adding an electron donating group having a function of absorbing light (light absorption function).

  In general, as the electron-donating group having a light absorption function, a dye group adopted in a dye-sensitized solar cell can be adopted. Examples of the material of the dye group include cyanine, merocyanine, squarylium, phthalocyanine, porphyrin, triphenylamine, and bipyridine Ru complex.

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

The nanostructure semiconductor material 17 includes a material having a structure having nanoscale dimensions as particle diameters and intergranular dimensions. The shape of the nanostructure semiconductor material 17 is not particularly limited, but in order to efficiently support the first electrochromic compound 16a or the second electrochromic compound 16b, the surface area per unit volume (hereinafter referred to as “ A shape having a large specific surface area) is used. For example, when the metal oxide 17 is an aggregate of nanoparticles, since it has a large specific surface area, the electrochromic compound is more efficiently supported, and a multicolor display excellent in display / decolor display contrast ratio is achieved. Is possible. Although it does not specifically limit as a specific surface area of the nanostructure semiconductor material 17, For example, it can be 100 m < ² > / g or more.

  A preferable film thickness range of the nanostructured semiconductor material 17 is 0.2 to 5.0 μm. When the film thickness is thinner than 0.2 μm, it is difficult to obtain the color density. On the other hand, when the film thickness is thicker than 5.0 μm, the manufacturing cost increases and the visibility tends to decrease due to coloring.

The material of the insulating layer 22 is not particularly limited as long as it is porous, but a material excellent in insulation, durability, and film formability can be used, and in particular, a material containing at least ZnS. Can be used. ZnS has a feature that it can be deposited at high speed by sputtering without damaging the electrochromic layer. Furthermore, ZnO—SiO ₂ , ZnS—SiC, ZnS—Si, ZnS—Ge, or the like can be used as a material containing ZnS as a main component. Here, the ZnS content is preferably about 50 to 90 mol% in order to maintain good crystallinity when the insulating layer 22 is formed. Therefore, particularly preferred materials are ZnS—SiO ₂ (8/2), ZnS—SiO ₂ (7/3), ZnS, ZnS—ZnO—In ₂ O ₃ —Ga ₂ O ₃ (60/23/10/7). ). By using such an insulating layer material, a good insulating effect can be obtained with a thin film, and a reduction in film strength (that is, peeling of the film) due to multilayering can be prevented.

  On the other hand, the insulating layer 22 can be made into a porous film by forming the insulating layer 22 as a particle film. Particularly when ZnS or the like is formed by sputtering, a porous film such as ZnS can be formed by previously forming a particle film as an undercoat layer. In this case, the nanostructure semiconductor material 17 can be formed as a particle film, but a porous particle film containing silica, alumina, or the like can also be formed as a part of the insulating layer 22. By making the insulating layer 22 into a porous film using such a technique, the electrolyte 20 can penetrate the insulating layer 22, and the insulating layer 22 can be permeable to the electrolyte 20; The movement of charges as ions in the electrolyte 20 accompanying the oxidation-reduction reaction is facilitated, and multicolor display with excellent response speed of color development and decoloration is possible.

  In addition, the film thickness of the insulating layer 22 can be 20-500 nm, More preferably, it can be set as the range of 50-150 nm. When the film thickness is less than 20 nm, it is difficult to obtain insulation. In addition, when the film thickness is thicker than 500 nm, the manufacturing cost increases and the visibility decreases due to coloring.

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

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

  Next, the materials of the electrolyte 20 and the white reflective layer 21 constituting the cell 19 will be described.

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

  Examples of the material of the white pigment particles contained in the white reflective layer 21 include titanium oxide, aluminum oxide, zinc oxide, silica, cesium oxide, yttrium oxide, and the like.

Moreover, it can also serve as a white reflective layer by mixing white pigment particles in the polymer electrolyte.
(Modification of the first embodiment)
Next, a modification of the first embodiment will be described with reference to FIG.

  FIG. 3 is a cross-sectional view schematically showing the configuration of the electrochromic display device 10a according to this modification. However, in the following text, the same reference numerals are given to the parts described above, and the description may be omitted (the same applies to the following embodiments).

  The electrochromic display device 10a according to the present modification is the electrochromic device according to the first embodiment in that three display layers and three electrochromic layers provided in contact with the display electrode are stacked in the display unit 1a. Different from the display device 10.

  On the other hand, in the electrochromic display device 10a according to this modification, the light irradiation unit 2 is the same as that in the first embodiment. That is, the light irradiation unit 2 includes a light irradiation amount control unit 23, an LED driver 24, and an irradiation head 25.

  Referring to FIG. 3, in the first embodiment, the electrochromic display device 10a according to the present modification is different from the display electrode and two electrochromic layers provided in contact with the display electrode. In this case, three layers each of a display electrode and an electrochromic layer provided in contact with the display electrode are laminated.

  That is, the display substrate 11a includes a first display electrode 13a formed on the display substrate 11a, a first electrochromic layer 14a provided in contact with the first display electrode 13a, and a first electrochromic layer 14a. A first insulating layer 22a provided in contact with the first insulating layer 22a, a second display electrode 13b provided in contact with the first insulating layer 22a, and a second electroelectrode provided in contact with the second display electrode 13b. A chromic layer 14b, a second insulating layer 22b provided in contact with the second electrochromic layer 14b, a third display electrode 13c provided in contact with the second insulating layer 22b, and a third display And a third electrochromic layer 14c provided in contact with the electrode 13c.

  The electrochromic display device 10a can easily perform multicolor display by having the above-described structure. Since the first display electrode 13a, the second display electrode 13b, and the third display electrode 13c are provided separately via the first insulating layer 22a and the second insulating layer 22b, the counter electrode 15, the potential of the first display electrode 13 a with respect to 15, the potential of the second display electrode 13 b with respect to the counter electrode 15, and the potential of the third display electrode 13 c with respect to the counter electrode 15 can be controlled independently. As a result, the first electrochromic layer 14a provided in contact with the first display electrode 13a, the second electrochromic layer 14b provided in contact with the second display electrode 13b, and the third display electrode 13c. The third electrochromic layer 14c provided in contact with each other can be independently developed and decolored. In addition, by performing the same operation as the multicolor display operation of the electrochromic display device 10 according to the first exemplary embodiment, it is possible to independently develop colors in combination with the light irradiation conditions.

  Since the first electrochromic layer 14a, the second electrochromic layer 14b, and the third electrochromic layer 14c are stacked on the display substrate 11a side, the first electrochromic layer 14a, The color development / decoloration pattern of the second electrochromic layer 14b and the third electrochromic layer 14c allows the color development of only the first electrochromic layer 14a, the color development of only the second electrochromic layer 14b, and the third electrochromic layer. Color development of only the layer 14c, color development by two layers of the first electrochromic layer 14a and the second electrochromic layer 14b, color development by two layers of the first electrochromic layer 14a and the third electrochromic layer 14c, second Electrochromic layer 14b and third electrochromic layer The color can be changed to two colors, ie, the first electrochromic layer 14a, the second electrochromic layer 14b, and the third electrochromic layer 14c, and multicolor display is possible. is there.

  In addition, as the first electrochromic layer 14a, the second electrochromic layer 14b, and the third electrochromic layer 14c, electrochromic layers that color yellow, magenta, and cyan are used, and the first display electrode 13a and the second electrochromic layer 14c are used. The electrochromic display device 10a can perform full-color display by independently controlling the potentials of the display electrode 13b and the third display electrode 13c.

  Also in this modification, an intermediate color can be developed by continuously changing the intensity of light to be irradiated or the time to irradiate light and changing the reduction amount of the electrochromic compound. Furthermore, by controlling stepwise the intensity of light to be irradiated or the time to irradiate light, an intermediate color can be developed without analog control. That is, it is possible to develop an intermediate color by irradiating light as a light pulse and changing the light intensity value, the pulse width, and the number of times the light pulse is applied.

Further, by controlling the voltage to be applied and the time for applying the voltage continuously to change the reduction amount of the electrochromic compound, it is possible to develop an intermediate color. Furthermore, an intermediate color can be developed by applying a voltage as a voltage pulse and changing the maximum voltage value of the voltage pulse, the pulse width, and the number of times the voltage pulse is applied.
(Second Embodiment)
Next, a second embodiment will be described with reference to FIG.

  FIG. 4 is a cross-sectional view schematically showing the configuration of the electrochromic display device 10b according to the present embodiment.

  The electrochromic display device 10b according to the present embodiment is different from the electrochromic display device 10 according to the first embodiment in that it does not have a display electrode and a counter electrode.

  On the other hand, in the electrochromic display device 10b according to the present embodiment, the light irradiation unit 2 is the same as that in the first embodiment. That is, the light irradiation unit 2 includes a light irradiation amount control unit 23, an LED driver 24, and an irradiation head 25.

  Referring to FIG. 4, unlike the first embodiment having the display electrode and the counter electrode, the electrochromic display device 10b according to the present embodiment includes the display electrode and the counter electrode in the display unit 1b. Does not have.

  The display substrate 11b includes a first electrochromic layer 14a formed on the display substrate 11b, an insulating layer 22 provided in contact with the first electrochromic layer 14a, and a second electrode provided in contact with the insulating layer 22. Electrochromic layer 14b.

  The first electrochromic layer 14a includes a first electrochromic compound 16a adsorbed on the nanostructured semiconductor material 17, and the first electrochromic layer 14a is irradiated with light having a wavelength that is absorbed by the first electrochromic layer 14a. The electrochromic compound 16a is oxidized or reduced to develop color.

  The second electrochromic layer 14b includes the second electrochromic compound 16b adsorbed to the nanostructured semiconductor material 17, and the second electrochromic layer 14b is irradiated with light having a wavelength that is absorbed by the second electrochromic layer 14b. The second electrochromic compound 16b is oxidized or reduced to develop color.

  The first electrochromic layer 14a or the second electrochromic layer 14b is provided with a difference in light absorption or reduction potential of the electrochromic layer with respect to the light irradiated from the LED, whereby the light amount (intensity) of the light irradiated from the LED. ) Or the color development sensitivity can be set differently with respect to the wavelength.

  When a sensitivity difference is set for the amount (intensity) or wavelength of LED light emitted from the LED, an arbitrary electrochromic layer can be selected by using different numbers of LED light sources corresponding to the number of electrochromic layers Color can be developed.

  Also in the present embodiment, it is possible to develop an intermediate color by controlling the intensity of irradiation light or the irradiation time continuously to change the reduction amount of the electrochromic compound. Furthermore, by controlling stepwise the intensity of light to be irradiated or the time to irradiate light, an intermediate color can be developed without analog control. That is, it is possible to develop an intermediate color by irradiating light as a light pulse and changing the light intensity value, the pulse width, and the number of times the light pulse is applied.

(Formation of display part)
First, a quartz glass substrate of 30 mm × 30 mm and a thickness of 1 mm is prepared as a display substrate, and a titanium oxide nanoparticle dispersion (trade name: SP210, manufactured by Showa Titanium Co., Ltd., average particle diameter: about 20 nm) is prepared on the glass substrate. The nanostructured semiconductor material composed of a titanium oxide particle film having a thickness of about 1.5 μm was formed by applying the film by spin coating and performing an annealing treatment at 120 ° C. for 15 minutes. Subsequently, equation (2)

で表される化合物の１ｗｔ％２，２，３，３−テトラフロロプロパノール溶液をスピンコート法により塗布し、１２０℃で１０分間アニール処理を行うことによって、酸化チタンナノ粒子に吸着させて、エレクトロクロミック層を形成した。

A 1 wt% 2,2,3,3-tetrafluoropropanol solution of the compound represented by formula (1) is applied by spin coating and annealed at 120 ° C. for 10 minutes to be adsorbed on the titanium oxide nanoparticles and electrochromic. A layer was formed.

  The light transmission spectrum measurement result of the electrochromic layer formed as described above is shown in FIG. FIG. 5 shows the measurement result of the display substrate on which the nanostructure semiconductor material and the electrochromic layer are formed in “quartz glass / titanium oxide / compound”, and the measurement result of the display substrate on which only the nanostructure semiconductor material is formed is shown in “quartz glass”. / Titanium oxide "and the measurement results of the display substrate only are shown in" Quartz glass ". In the results of optical transmission spectrum measurement of “quartz glass / titanium oxide” and “quartz glass / titanium oxide / compound” in FIG. 5, as the wavelength decreases, the transmittance starts to decrease from about 400 nm and is approximately 350 nm or less. The transmittance becomes 0 in the wavelength band. That is, the electrochromic layer according to Example 1 has light absorption in a wavelength band of approximately 400 nm or less.

  Next, as a polymer electrolyte, a solution obtained by dissolving 10 wt% of perchloric acid chloride in polyethylene glycol (molecular weight: 200), propylene carbonate, and a UV curable adhesive (trade name: Loctite 3301, manufactured by Henkel) is used 3: After preparing a dispersion liquid in which 5 wt% of titanium oxide particles (trade name: CR50, manufactured by Ishihara Sangyo Co., Ltd.) was added as a white reflective layer to the solution mixed at 4: 5, and applied dropwise onto the electrochromic layer surface side, A glass substrate having a size of 30 mm × 30 mm and a thickness of 1 mm was stacked as a counter substrate and bonded by UV light irradiation and curing. The electrochromic layer was colored blue by this UV light irradiation. This color development disappeared after 2 days and became a white display surface.

By the above operation, a display unit 1c according to Example 1 made of one electrochromic layer was obtained.
(Color development test)
From the display substrate side of the display unit 1c according to Example 1, using an LED light irradiation device (trade name: LC-C2, manufactured by Hamamatsu Photonics), pulsed light with an irradiation area of 3 mmφ, 5 W / cm ² , 0.2 sec. When irradiated with 365 nm LED light under the above conditions, the irradiated region developed a blue color.

  This coincides with the fact that the electrochromic layer of the display unit 1c according to Example 1 has good light absorption at a wavelength of about 400 nm or less, as shown in the light transmission spectrum measurement result of FIG.

(Formation of display part)
In Example 1, the first display electrode was formed by forming an ITO film on the display substrate surface to a thickness of about 100 nm by sputtering, and the ITO film was formed on the counter substrate surface. The counter electrode was formed by forming a film with a thickness of about 100 nm by sputtering, and an electrochromic compound represented by the formula (3)

で表される化合物にしたこと以外は同様にして、一のエレクトロクロミック層と電極を有してなる実施例２に係る表示部１ｄを得た。
（発消色試験）
実施例２に係る表示部１ｄの表示基板側から、ＬＥＤ光照射装置（商品名：ＬＣ−Ｃ２、浜松フォトニクス社製）を用いて、照射領域３ｍｍφ、３Ｗ／ｃｍ^２、０．２ｓｅｃのパルス光の条件で、３６５ｎｍのＬＥＤ光を照射したところ、照射領域が緑色に発色した。

A display unit 1d according to Example 2 having one electrochromic layer and an electrode was obtained in the same manner except that the compound represented by formula (1) was used.
(Color development test)
From the display substrate side of the display unit 1d according to Example 2, using an LED light irradiation device (trade name: LC-C2, manufactured by Hamamatsu Photonics), pulsed light with an irradiation area of 3 mmφ, 3 W / cm ² , 0.2 sec. When irradiated with 365 nm LED light under the above conditions, the irradiated area was colored green.

  Furthermore, when the irradiation unit head was moved and continuously irradiated, a line image was formed.

  Next, when a decoloring voltage of 4.5 V was applied between the display electrode and the counter electrode so that the display electrode was positive, the image was decolored and returned to white.

(Formation of display part)
First, by preparing a glass substrate having a thickness of 30 mm × 30 mm and a thickness of 1 mm as a display substrate, and depositing an ITO film to a thickness of about 100 nm by a sputtering method on a 25 mm × 25 mm region on the upper surface thereof, A first display electrode was formed. When the sheet resistance between the electrode end portions of the first display electrode was measured, it was about 200Ω.

  Next, a titanium oxide nanoparticle dispersion (trade name: SP210, manufactured by Showa Titanium Co., Ltd., average particle diameter: about 20 nm) is applied onto the glass substrate on which the first display electrode is formed in this manner by a spin coating method. Then, a nanostructured semiconductor material made of a titanium oxide particle film having a thickness of about 1.5 μm was formed by annealing at 120 ° C. for 15 minutes. Subsequently, as an electrochromic compound, a 1 wt% 2,2,3,3-tetrafluoropropanol solution of the compound represented by the formula (3) is applied by a spin coating method and annealed at 120 ° C. for 10 minutes. By adsorbing to titanium oxide nanoparticles, a first electrochromic layer was formed.

Next, on the glass substrate on which the first electrochromic layer is formed in this manner, as a polymer electrolyte, a solution of perchloric acid chloride dissolved in polyethylene glycol (molecular weight: 200) by 10 wt%, propylene carbonate, UV A solution obtained by mixing a cured adhesive (trade name: Loctite 3301, manufactured by Henkel) at a ratio of 1: 34: 1.5 is applied by spin coating, and annealed at 120 ° C. for 5 minutes, thereby providing an electrolyte function. A polymer insulating layer was formed. Subsequently, an inorganic insulating layer was formed by depositing ZnS—SiO ₂ having a composition ratio of 8: 2 to a film thickness of about 50 nm by a sputtering method. Furthermore, an ITO film is formed to a thickness of about 100 nm by a sputtering method in a 20 mm × 20 mm region on the surface of the glass substrate on which the inorganic insulating layer made of ZnS—SiO ₂ is formed. The display electrode was formed.

  The sheet resistance between the electrode end portions of the second display electrode formed as described above was measured. As a result, the sheet resistance between the electrode ends was about 200Ω.

  Next, a titanium oxide nanoparticle dispersion (trade name: SP210, manufactured by Showa Titanium Co., Ltd., average particle size: about 20 nm) is applied onto the glass substrate on which the second display electrodes have been formed in this way by a spin coating method. Then, a nanostructured semiconductor material made of a titanium oxide particle film having a thickness of about 1.5 μm was formed by annealing at 120 ° C. for 15 minutes. Subsequently, as an electrochromic compound, a 1 wt% 2,2,3,3-tetrafluoropropanol solution of the compound represented by the formula (2) is applied by a spin coating method and annealed at 120 ° C. for 10 minutes. By adsorbing to titanium oxide nanoparticles, a second electrochromic layer was formed. Here, resistance measurement between the first display electrode and the second display electrode was performed. The result was 40 MΩ or more, which was a good insulating property.

  Furthermore, the light transmission spectrum measurement result of the electrochromic layer formed as described above is shown in FIG. In the light transmission spectrum measurement result in FIG. 6, as the wavelength decreases, the transmittance starts to decrease from approximately 400 nm, and the transmittance becomes 0 in a wavelength band of approximately 350 nm or less. That is, the electrochromic layer according to Example 3 has light absorption in a wavelength band of approximately 400 nm or less.

  On the other hand, a counter substrate was formed by preparing a 30 mm × 30 mm glass substrate separately from the glass substrate and forming a transparent conductive thin film made of tin oxide on the entire upper surface. Further, 25 wt% of 2-ethoxyethyl acetate is added to CH10 (trade name: manufactured by Jujo Chemical Co., Ltd.) as a thermosetting conductive carbon ink on the upper surface of the glass substrate on which the transparent conductive thin film made of tin oxide is formed on the entire surface. The prepared solution was applied by spin coating and annealed at 120 ° C. for 5 minutes to form a counter electrode.

  Furthermore, a solution obtained by dissolving 10% by weight of perchloric acid chloride in polyethylene glycol (molecular weight: 200), propylene carbonate, and a UV curable adhesive (trade name: Loctite 3301, manufactured by Henkel Co., Ltd.) 3: 4: Prepare a dispersion with 40 wt% of titanium oxide particles (trade name: CR50, manufactured by Ishihara Sangyo Co., Ltd.) added to the solution mixed in 5 as a white reflective layer, apply by spin coating, and anneal at 120 ° C. for 15 minutes Was performed to form a white reflective layer.

  Next, as a polymer electrolyte, a solution obtained by dissolving 10 wt% of perchloric acid chloride in polyethylene glycol (molecular weight: 200), propylene carbonate, and a UV curable adhesive (trade name: Loctite 3301, manufactured by Henkel) is used 3: A solution mixed at 4: 5 was prepared, applied dropwise onto the surface side of the second electrochromic layer, and then overlapped with the white reflecting surface side of the counter substrate and bonded by UV light irradiation and curing. The electrochromic layer was colored black by this UV light irradiation. This color development disappeared after 2 days and became a white display surface.

Through the above operation, a display unit 1e according to Example 3 was obtained.
(Color-decoloration test-1)
From the display substrate side of the display unit 1e according to Example 3, using an LED light irradiation device (trade name: LC-C2, manufactured by Hamamatsu Photonics), pulsed light with an irradiation area of 3 mmφ, 7 W / cm ² , 0.5 sec. When the 365-nm LED light was irradiated under the above conditions, both the first electrochromic layer and the second electrochromic layer were colored, and the irradiated region was colored black.

  Furthermore, when the irradiation part head was moved and irradiated continuously, the black line image was formed.

  This coincides with the fact that the electrochromic layer of the display unit 1e according to Example 3 has good light absorption at a wavelength of about 400 nm or less, as shown in the light transmission spectrum measurement result of FIG.

  Next, when a decoloring voltage of 4.5 V is applied between the second display electrode and the counter electrode so that the second display electrode is positive, the second electrochromic layer is decolored. It became a green line image. This is a green color due to the first electrochromic layer.

  Next, after forming a black line image in the same manner as described above, a 4.5 V decoloring voltage was applied between the first display electrode and the counter electrode so that the first display electrode was positive. The first electrochromic layer developed color and became a blue line image. This is a blue coloration by the second electrochromic layer.

By the above driving operation, individual display of black, green, and blue is possible.
(Color development test-2)
From the display substrate side of the display unit 1e according to Example 3, using an LED light irradiation device (trade name: LC-C2, manufactured by Hamamatsu Photonics), pulsed light with an irradiation area of 3 mmφ, 7 W / cm ² , 0.5 sec. When the 365-nm LED light was irradiated under the above conditions, both the first electrochromic layer and the second electrochromic layer were colored, and the irradiated region was colored black.

  Furthermore, when the irradiation part head was moved and irradiated continuously, the black line image was formed.

  Next, when a decoloring voltage of 4.5 V is applied between the first display electrode and the counter electrode so that the first display electrode is positive, the first electrochromic layer is decolored. It became a blue line image. This is a blue coloration by the second electrochromic layer.

Furthermore, when irradiating LED light with a wavelength of 385 nm under the conditions of a newly irradiated region of 3 mmφ, 2 W / cm ² and a pulse of 0.5 sec, only the first electrochromic layer is decolored and the irradiated region becomes green. Color developed. Furthermore, when the irradiation part head was moved and it irradiated continuously, the green line image was formed.

Furthermore, when the LED light of 385 nm is irradiated under the conditions of a new irradiation region of 3 mmφ, 7 W / cm ² and pulsed light of 0.5 sec, both the first electrochromic layer and the second electrochromic layer are colored. The irradiated area was colored black.

  Furthermore, when the irradiation part head was moved and irradiated continuously, the black line image was formed.

  By the above driving operation, simultaneous display of black, green and blue is possible.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to such specific embodiments, and various modifications can be made within the scope of the gist of the present invention described in the claims. Can be modified or changed.

1, 1a, 1b Display unit 2 Light irradiation unit 10, 10a, 10b Electrochromic display device 11, 11a, 11b Display substrate (transparent substrate)
12 counter substrate 13a first display electrode 13b second display electrode 13c third display electrode 14a first electrochromic layer 14b second electrochromic layer 14c third electrochromic layer 15 counter electrode 16a first electro Chromic compound 16b Second electrochromic compound 17 Nanostructure semiconductor material (semiconductor material having nanostructure)
18 Spacer 19 Cell 20 Electrolyte 21 White Reflective Layer 22, 22a, 22b Insulating Layer 23 Light Irradiation Control Unit 24 LED Driver 25 Irradiation Head

Special table 2001-510590 gazette JP 2003-121883 A JP 2006-106669 A JP 2003-270671 A JP 2004-151265 A JP 2000-292818 A Japanese Unexamined Patent Publication No. 60-11877

Claims (17)

A display substrate, a counter substrate,
In an electrochromic display device having an electrochromic layer and an electrolyte provided so as to be sandwiched between the display substrate and the counter substrate,
The electrochromic layer includes an electrochromic compound adsorbed on a semiconductor material having a nanostructure, and develops color when irradiated with light having a wavelength that the electrochromic layer absorbs light. A display electrode provided in contact with the electrochromic layer between the display substrate and the electrochromic layer;
The electrochromic display device according to claim 1, further comprising a counter electrode provided between the counter substrate and the electrochromic layer. A plurality of the display electrodes are provided separately from each other between the display substrate and the counter electrode,
The plurality of electrochromic layers are provided corresponding to each of the plurality of display electrodes,
The electrochromic display device according to claim 2, wherein an electrical resistance between one display electrode and the other display electrode is larger than an electrical resistance of the one display electrode.   The electrochromic display device according to claim 3, wherein the plurality of electrochromic layers are colored in different colors.   5. The electrochromic display device according to claim 3, wherein the plurality of electrochromic layers have different color development sensitivities with respect to the intensity or wavelength of light to be irradiated.   The electrochromic display device according to claim 2, wherein the display electrode is a transparent electrode.   The electrochromic display device according to claim 6, wherein the display electrode provided between the display electrode closest to the display substrate and the counter electrode has permeability to an electrolyte.   8. The electrochromic display device according to claim 2, wherein an insulating layer for insulating the plurality of display electrodes from each other is provided between the plurality of display electrodes. 9.   The electrochromic display device according to claim 8, wherein the insulating layer is permeable to an electrolyte.   The electrochromic display device according to claim 8, wherein the insulating layer includes a polymer that functions as an electrolyte.   11. The electrochromic display device according to claim 2, further comprising a reflective layer between the electrochromic layer and the counter electrode or on the opposite side of the counter substrate from the counter electrode. . The nanostructured semiconductor material includes titanium oxide particles,
The electrochromic display device according to any one of claims 2 to 11, wherein the electrochromic compound includes a dipyridine organic material represented by the following general formula (1).

(Wherein R1 and R2 each independently represents an alkyl group having 1 to 4 carbon atoms which may have a substituent or an aryl group, and at least one of R1 and R2 is COOH, PO (OH) _2. , Si (OC _k H _{2k + 1} ) having one group selected from _3. X represents a monovalent anion, n represents 0, 1 or 2. A represents the carbon number that may have a substituent. 1 to 20 alkyl groups, aryl groups and heterocyclic groups are represented.) A method for driving an electrochromic display device according to any one of claims 2 to 12,
The electrochromic layer is decolored by applying a driving voltage for decoloring the colored electrochromic layer between the display electrode in contact with the electrochromic layer and the counter electrode. Driving method of electrochromic display device.   By applying a driving voltage for erasing driving between the one display electrode in contact with the one electrochromic layer and the counter electrode, and insulating the other display electrode from the counter electrode, the one electrode 14. The method of driving an electrochromic display device according to claim 13, wherein only the electrochromic layer is decolored.   6. The method of driving an electrochromic display device according to claim 5, wherein only the one electrochromic layer is colored by irradiating light having an intensity or wavelength that causes only one electrochromic layer to be colored. A method for driving an electrochromic display device.   6. The method of driving an electrochromic display device according to claim 5, wherein the display electrode is opposed to the display electrode in contact with the other electrochromic layer while irradiating light having an intensity or a wavelength for developing the color of the electrochromic layer. A driving method of an electrochromic display device, wherein only the one electrochromic layer is colored by applying a driving voltage for erasing driving between the electrodes.   The method of driving an electrochromic display device according to any one of claims 1 to 12, wherein an intermediate color is applied to the electrochromic layer by controlling stepwise the intensity of light to be irradiated or the time to irradiate light. A method for driving an electrochromic display device, characterized in that color is developed.

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