JP5269673B2 - Display element and method for manufacturing display element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display element being inexpensively manufacturable. <P>SOLUTION: The display element includes: a bacteria cellulose support body formed by bacteria cellulose having pore volume of 0.4 mL/g or more; a display electrode formed on a face on one side of the bacteria cellulose support body, an opposing electrode formed on a face on the other side of the bacteria cellulose support body; and a color developing material causing color change reversibly by the electrolyte included in the bacteria cellulose support body and oxidation-reduction reaction. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a display element and a method for manufacturing the display element.

  Electronic shelf labels, electronic tags, and electronic paper are being studied as electronic media to replace paper. In particular, an electronic shelf label and an electronic tag that incorporate RFID (Radio Frequency Identification) are promising as a medium for dramatically improving merchandise management. Electronic shelf labels, electronic tags, and electronic paper display parts are easy to read letters and numbers (high white reflectance, high contrast ratio), low power consumption (display has memory characteristics, low It can be driven by voltage), is thin and light, and is inexpensive.

  At present, most of the display methods of electronic shelf labels, electronic packing tags, and electronic papers in practical use are reflective liquid crystal methods. The reflective liquid crystal element has an advantage that it can be manufactured at low cost because it does not require a backlight, consumes less power, and can use existing liquid crystal production equipment. However, since the liquid crystal system requires a polarizing plate, the light use efficiency is low, the white reflectance of the image and the contrast ratio are bad, and a color filter is used for colorization. However, this method has a problem that it is difficult to display a color with good visibility.

  On the other hand, in recent years, an electrophoretic method for performing display by moving charged white particles and black particles by an electric field as a bright reflective display element has been studied. However, even in this electrophoresis method, it is difficult to completely invert white particles and black particles by an electric field, and white reflectance and contrast ratio comparable to those of paper cannot be obtained. In addition, regarding colorization, methods such as forming a color filter on an electrophoretic element and moving a plurality of particles colored in a plurality of colors are conceivable, but it is difficult to achieve a high-quality display similar to paper. It is.

  In addition, there is a display element that performs coloring and decoloring using an electrochromic compound. This is a display element using an electrochromic compound in which electric field oxidation or electric field reduction reaction occurs reversibly when voltage is applied, and color change reversibly occurs. A display element using such an electrochromic compound is a reflective display element, which can obtain a high white reflectance and contrast ratio, and can be driven at a low voltage. As a good candidate.

  Patent Documents 1 to 3 disclose an element that performs coloring and decoloring with high efficiency by using an element in which an organic electrochromic compound is supported on the surface of semiconductor fine particles such as titanium oxide. Patent Document 4 discloses a technique related to a full-color display medium that exhibits high white reflectance and contrast ratio using an electrochromic compound.

  However, it is considered that the manufacturing cost of the display element using the electrochromic compound disclosed in Patent Documents 1 to 4 is almost the same as that of a display system such as a liquid crystal and is expensive. On the other hand, for applications such as electronic paper that are expected to be used multiple times per person, extremely low-priced products are desired, and in addition, electronic shelf labels and electronic tags are expected to be used in large quantities. Therefore, an even lower price is desired. Therefore, it is difficult to use the display elements disclosed in Patent Documents 1 to 4 for applications such as electronic paper.

  The present invention has been made in view of the above, and an object of the present invention is to provide a low-cost, thin and lightweight display element having a high white reflectance and a high contrast ratio, and a method for manufacturing the display element.

  The present invention includes a cellulose support obtained by adding pulp fibers to bacterial cellulose, a display electrode formed on one surface of the cellulose support, a counter electrode formed on the other surface of the cellulose support, And an chromogenic material capable of reversibly changing color by an oxidation-reduction reaction and an electrolyte contained in the cellulose support.

  Further, the present invention is characterized in that the content of pulp fibers with respect to bacterial cellulose in the cellulose support is less than 75%.

  Further, the present invention is characterized in that the pore volume in the cellulose support is 0.4 mL / g or more.

  Further, the present invention is characterized in that a color is generated or decolored in the color forming material by passing a current between the display electrode and the counter electrode.

  In the invention, it is preferable that the color forming material contains an electrochromic compound.

  Further, the present invention is characterized in that the cellulose support, the display electrode, and the counter electrode are covered with an electrolyte sealing layer.

  Further, the present invention is characterized in that the electrolyte sealing layer has oil resistance.

  Further, the present invention is characterized in that a plurality of the display elements are stacked, and the color forming materials in the respective display elements develop different colors.

  Further, the present invention includes adding a pulp resin to bacterial cellulose to form a cellulose support, forming a display electrode on one surface of the cellulose support, and forming a counter electrode on the other surface; A step of impregnating the bacterial cellulose support with a coloring material capable of reversibly changing color by an electrolyte and an oxidation-reduction reaction.

  Further, the present invention is characterized in that the display electrode or the counter electrode is formed by sputtering or vacuum deposition of a transparent electrode material or a metal material.

  According to the present invention, it is possible to provide a low-cost, thin and light display element having a high white reflectance and a high contrast ratio, and a method for manufacturing the display element.

Configuration diagram of display element in first embodiment Configuration diagram of display element in second embodiment The block diagram of the display element in 3rd Embodiment

  The form for implementing this invention is demonstrated below.

[First Embodiment]
The display element in 1st Embodiment is demonstrated based on FIG. In the display element according to the present embodiment, a cellulose support 11 obtained by adding pulp fibers to bacterial cellulose is impregnated with an electrolytic solution containing the chromophoric material 12 and displayed on the substrate 13 from one surface of the cellulose support 11. The display electrode substrate 15 on which the electrode 14 is formed and the counter electrode substrate 18 on which the counter electrode 17 is formed on the substrate 16 from the other surface are sandwiched.

  In this display element, when a predetermined voltage is applied between the display electrode 14 and the counter electrode 17, charge is transferred between the color forming material 12 in the cellulose support 11 and the display electrode 14. Coloring and decoloring occur due to the accompanying oxidation-reduction reaction, and image display is performed.

  Bacterial cellulose is a medium containing carbohydrates and is a cellulose film produced by certain microorganisms that are discharged outside the cells. Ribbon-like fine fibers with a width of several tens of nanometers have a network structure and are compared with pulp fibers. Each fiber is extremely fine. The characteristics of bacterial cellulose are almost the same as the appearance of general paper made of cellulose. At the same time, the internal structure of the fine fibers has a high proportion of voids (pore volume) in the total volume, Absorption performance and retention performance when impregnated are high. The inventors pay attention to the fact that the pore volume is high, and after dissolving or dispersing the chromogenic material 12 and the electrolyte that can repeatedly change color by an oxidation-reduction reaction in a solvent, the inside of the cellulose support 11 The display electrode 14 is formed on one surface of the cellulose support 11 and the counter electrode 17 is formed on the other surface.

  Cellulose support 11 used in the present embodiment has a pore volume of 0.4 mL / g or more, can be sufficiently infiltrated with an electrolytic solution containing chromogenic material 12, and a display element can be obtained. it can.

  However, it is difficult to control the smoothness of the surface of the bacterial cellulose, and when the support is formed of a material consisting only of bacterial cellulose, the smoothness of the surface of the bacterial cellulose support is poor. It was confirmed that the contact between the display electrode and the counter electrode was also deteriorated, and in the portion where the contact between the bacterial cellulose support and the display electrode and the counter electrode was poor, no charge was transferred, resulting in display failure.

  In view of such points, the inventors have conducted intensive studies and found that smoothness is improved by using a support obtained by adding pulp fibers to bacterial cellulose. Furthermore, even when pulp fibers are added to bacterial cellulose, it is found that the pore volume of the cellulose support 11 can be 0.4 mL / g or more, and a good display element is produced. Became possible.

  In this embodiment, the bacterial cellulose constituting the cellulose support 11 is defibrated after washing the bacterial cellulose produced by the bacteria in the medium, dispersed in a solvent and filtered to form a sheet and dried. To make. Here, if only bacterial cellulose with very fine fibers is used, the fibers tend to agglomerate with each other, resulting in a very slow filtration rate. On the other hand, when pulp fibers having thick fibers are added, the fibers are less likely to aggregate and the filtration rate can be increased. It is considered that the aggregation in the formed cellulose support 11 is improved and the smoothness of the surface is improved by preventing aggregation during filtration and increasing the filtration rate.

Table 1 shows the relationship between the pulp fiber content in the cellulose support 11 and the surface smoothness of the cellulose support 11. The smoothness of the cellulose support 11 is evaluated by measuring five different thicknesses on the surface of the cellulose support 11 and calculating the standard deviation of the thickness. This was done by calculating the surface roughness (%).

Surface roughness of cellulose support = standard deviation / thickness of cellulose support (1)

具体的には、バクテリアセルロースに対してパルプ繊維の含有率が０％、２５％、
５０％、７５％となるセルロース支持体１１を作製した。バクテリアセルロースに対
してパルプ繊維の含有率が２５％、５０％のセルロース支持体では表面の粗さが小さくなり平滑性が向上する傾向にある。一方、バクテリアセルロースに対してパルプ繊維の含有率が７５％のセルロース支持体１１では、パルプ繊維を含有しない場合（パルプ繊維の含有率が０％の場合）よりも表面の粗さは大きくなった。これにより、バクテリアセルロースに対してパルプ繊維を７５％未満加えることにより、凝集を抑えることができ平滑性を向上させることが可能である。

Specifically, the content of pulp fibers with respect to bacterial cellulose is 0%, 25%,
Cellulose support 11 having 50% and 75% was produced. A cellulose support having a pulp fiber content of 25% or 50% relative to bacterial cellulose tends to have a reduced surface roughness and improved smoothness. On the other hand, in the cellulose support 11 having a pulp fiber content of 75% with respect to bacterial cellulose, the surface roughness was larger than when the pulp fiber was not contained (when the pulp fiber content was 0%). . Thereby, by adding less than 75% of pulp fiber to bacterial cellulose, aggregation can be suppressed and smoothness can be improved.

  In addition, when the roughness of the surface of the cellulose support 11 is within about 3%, it has been found that the contact between the cellulose support 11 and the display electrode 14 and the counter electrode 17 is good. From the above, the pulp fiber content G with respect to bacterial cellulose is 0% <G <75%, preferably 0% <G ≦ 50%, more preferably 25% ≦ G ≦ 50%. A cellulose support 11 having a high surface smoothness can be obtained. Accordingly, the display quality of the manufactured display element can be improved and the yield of the display element can be improved, so that the display element can be manufactured at low cost.

  The image display method of the display element in this embodiment is the same as the image display method in a general electrochromic display, electrodeposition display, or the like. A feature of the display element in the present embodiment is that the cellulose support 11 has a function as a spacer part between the white reflective layer and the display electrode and the counter electrode, so that the number of components can be reduced. A display element can be manufactured at low cost.

  The bacterial cellulose constituting the cellulose support 11 used in the present embodiment is cellulose composed of ribbon-like microfibrils having a width of about 15 to 60 nm, and is cellulose produced by microorganisms, β-1,4 glucan Or a mixture of these glucans such as β-1,3, β-1,2 and the like. Such bacterial cellulose is in a gel form.

  Constituent components other than cellulose in the case of heteropolysaccharides are hexoses such as mannose, fructose, galactose, xylose, arabinose, rhamnose, glucuronic acid, pentoses, organic acids and the like.

  Examples of microorganisms that produce bacterial cellulose include bacteria such as Gluconacetobacter genus, Enterobacter genus, Agrobacterium genus, and Rhizobium genus. For example, Gluconacetobacter xylinus ATCC 53582 or Gluconacetobacter hansenii, Acetobacter pasteurianus, ent. Microorganisms producing bacterial cellulose such as (Bacterium xyloides) can be used. The bacterial cellulose used in the present embodiment may be one produced by these microorganisms or a mixture of those produced by these microorganisms.

  In addition, as a method for culturing microorganisms, in addition to those produced by static culture, those produced by electric stirring culture can be used.

  Examples of the electrolyte used in the present embodiment include an organic solvent such as acetonitrile, propylene carbonate, N-methylpyrrolidone, dimethyl sulfoxide, and polyethylene glycol, and lithium perchlorate, lithium borofluoride, tetrabutylammonium perchlorate, hexa Examples include those obtained by dissolving electrolytes such as tetrabutylammonium fluoroborate and tetrabutylammonium butylborate, ionic liquids, and combinations thereof.

  The chromogenic material 12 used in the present embodiment is capable of repeatedly performing color change between color development and decoloration by the oxidation-reduction reaction according to the present invention, and is reversible by electrochemical oxidation reaction and reduction reaction. Electrochromic compounds that can cause color changes, or metal elements that can be reversibly brought into an ionic state (transparent state) and an atomic state (black state, etc.) by electrochemical oxidation and reduction reactions It consists of

  The electrochromic compound may be either an inorganic electrochromic compound or an organic electrochromic compound. A conductive polymer exhibiting electrochromism can also be used. Examples of the inorganic electrochromic compound include tungsten oxide, molybdenum oxide, iridium oxide, and titanium oxide. Examples of the organic electrochromic compound include viologen, rare earth phthalocyanine, srityl, and phthalates. Further, the organic electrochromic compound may be a composition supported on the surface of a semiconductor such as titanium oxide or zinc oxide or conductive fine particles. Examples of the conductive polymer include polypyrrole, polythiophene, polyaniline, and the like. Examples of the metal element that can reversibly change the ionic state and the atomic state by an oxidation reaction and a reduction reaction include silver, bismuth, zinc, copper, and the like.

  From the above, especially in the case of electrochromic compounds, various colors can be developed depending on the compound structure, so that the most desirable color can be displayed depending on the application, and by combining these as described later Color display is also possible.

  As the display electrode 14 of the display element in the present embodiment, a transparent electrode is desirable. Specifically, a transparent conductive film made of a material such as ITO, IZO, AZO, FTO, ZnO or the like is used. As the counter electrode 17, a transparent conductive film made of a material such as ITO, IZO, AZO, FTO, or ZnO, or a conductive metal film such as zinc or platinum is used.

[Second Embodiment]
Next, the display element in 2nd Embodiment is demonstrated. In the display element according to the present embodiment, as shown in FIG. 2, the cellulose support 31 is impregnated with an electrolyte containing the chromogenic material 32, and the display electrode layer 33 is formed on one surface of the cellulose support 31. Then, the counter electrode layer 34 is formed on the other surface, and the cellulose support 31, the display electrode layer 33, and the counter electrode layer 34 are covered with the electrolyte sealing layer 35 to be sealed, and soaked into the cellulose support 31. The structure prevents leakage of the deposited electrolyte.

  In the display element in the present embodiment, since the cellulose support 31 is present on the entire surface of the display element, it is not necessary to provide a substrate or the like for supporting the display electrode layer 33 and the counter electrode layer 34. In a display in which each electrode is bonded through a general spacer, it is necessary to form each electrode on a substrate for supporting glass or plastic. By using a plastic substrate, it is possible to reduce the weight and to provide a certain degree of portability, but it is not possible to obtain portability such as being thin and rolled up and being carried like paper. Furthermore, when the display element has a large area, it is extremely difficult to bond a glass substrate or a plastic substrate with a uniform gap over the entire surface, resulting in an increase in manufacturing cost. In the case of a glass substrate, the formed display element becomes heavy, the portability is poor, and the manufacturing cost further increases.

  On the other hand, in the display element shown in FIG. 2 in the present embodiment, it is not necessary to provide a substrate for supporting the display electrode layer 33 and the counter electrode layer 34, and the electrolyte and color developability existing in the cellulose support 31. In order to seal the material 32, a thin electrolyte sealing layer 35 having a thickness of about several μm is provided. Therefore, for example, when a display element is produced using the cellulose support 31 having a thickness of about 0.3 mm, a display element having a thickness of about 0.3 mm can be produced. This thickness is about the same as the thickness of cardboard and the like, and has the same weight and bendability as cardboard and the like, and has portability that cannot be obtained with existing displays. Further, in the manufacturing process of the display element, it is not necessary to adjust a gap or the like at the time of bonding, and the display element can be manufactured at low cost.

  In addition, the bacterial cellulose constituting the cellulose support 11 of the display element in the present embodiment has the same components as paper. Therefore, in applications such as electronic shelf labels, electronic packing tags, and electronic paper that are used as substitutes for paper, the same white color as paper is used, so that visibility is high. Further, as described above, since the display element in the present embodiment can form the cellulose support 11 very thinly, it has almost no influence such as a decrease in light transmittance or a light interference due to a substrate for supporting. Without being received, the reflected light from the cellulose support 11 can be visually recognized as it is.

  In the display element in the present embodiment, an electrolyte sealing layer 35 is formed on the surface of the cellulose support 31 with the display electrode layer 33 and the counter electrode layer 34 interposed therebetween. The electrolyte is preferably a liquid so as to soak into the cellulose support 31, but it is necessary to prevent the soaked electrolyte from leaking from the cellulose support 31, thereby improving the durability of the display element. . In the first embodiment, the electrolyte sealing layer 35 can also serve this function in the substrate. In this embodiment, the electrolyte sealing layer 35 is formed by applying a film made of a polymer resin layer. .

  Since it is preferable to use an organic solvent with low volatility as the electrolyte solvent, it is preferable for the display element of the present embodiment that the electrolyte sealing layer 35 has oil resistance. Specifically, as the electrolyte sealing layer 35, when a polymer film such as a water-soluble polymer resin such as polyvinyl alcohol, vinyl urethane resin, acrylic resin, or acrylic acid resin is used, the electrolyte sealing layer 35 is thin and lightweight. A display element with a high sealing effect can be obtained. Further, when a protective film is further stacked on the surface of the electrolyte sealing layer 35, impact from the outside, scratches, and water resistance can be improved. Examples of the protective film used at this time include general-purpose water-resistant resins such as polyethylene, polypropylene, polycarbonate, and polystyrene. By using these materials, a thin and lightweight display element can be manufactured at low cost.

  Preferably, the display electrode layer 33 and the counter electrode layer 34 are formed by a vacuum film forming method. As a result of investigations by the inventors, the smoothness is improved in the cellulose support 31 in which a predetermined amount of pulp fiber is added to bacterial cellulose. Therefore, it is possible to form a highly conductive electrode film by a vacuum film forming method. I found out. As a method of forming the display electrode layer 33, a good transparent conductive film can be obtained by DC sputtering of a transparent electrode material such as ITO (Indium Tin Oxide). Furthermore, by conducting a heat treatment such as annealing after forming the transparent conductive film, the conductivity and transparency can be further improved. The method of forming the counter electrode layer 34 may be a method of forming a transparent electrode material by DC sputtering, but the counter electrode layer 34 having a low resistance can be formed by vacuum deposition of a metal material.

[Third Embodiment]
Next, a third embodiment will be described. In this embodiment, color display can be performed by stacking a plurality of display elements of the first embodiment or the second embodiment. That is, in the display element of the first embodiment or the second embodiment, when the thickness of the cellulose support is less than 0.3 μm, it becomes transparent when decolored. Therefore, even when a plurality of display elements are stacked, it is possible to visually recognize the lower display element on which the display elements are stacked. Therefore, by superimposing display elements that generate a plurality of different colors, it is possible to perform color display of each color and each color mixture.

  Specifically, as shown in FIG. 3, color display can be performed by superimposing the above-described display elements into a stacked display element. Specifically, in order from the top, the thickness of the cellulose support is less than 0.3 mm, and the colored state is the magenta display element 51, and the thickness of the cellulose support is less than 0.3 mm and the color is developed. Full color display can be performed by superimposing the yellow display element 52 and the cyan display element 53 where the thickness of the cellulose support is less than 0.3 mm and the colored state is superimposed. Note that the order of superimposing the display elements 51 to 53 may be any order.

  Further, the position where the person who becomes the lowermost display element 53 sees, that is, the thickness of the cellulose support of the display element 53 farthest from the position of the viewpoint is set to 0.3 mm or more, thereby increasing the white reflection. A multilayer display element capable of high-quality full-color display can be obtained. In this case, the thickness of the cellulose support of the display elements 51 and 52 existing between the viewpoint position and the display element 53 farthest from the viewpoint position is 0.3 mm or less.

Example 1
The display element in Example 1 was manufactured by the following manufacturing method. This example is the display element of the first embodiment.

  First, the cellulose support 11 was produced by the following method.

A medium (pH: 6.0) having the following composition was placed in a Erlenmeyer flask having a capacity of 200 mL and sterilized by steam at 120 ° C. for 20 minutes to prepare a culture solution.
Glucose 2.0%
Bactopeptone 0.5%
Yeast extract 0.5%
Citric acid 0.115%
Disodium hydrogen phosphate 0.27%
Next, this culture broth was inoculated with one platinum loop of glucone Acetobacter xylinus ATCC 53582 stored at −80 ° C., and cultured at 30 ° C. for 5 days to form a bacterial cellulose film. Thereafter, the bacterial cellulose membrane was aseptically taken out, and a bacterial cellulose membrane was produced by replacing the half amount of the medium by the number of times of replacement (half amount). The bacterial cellulose membrane was immersed in 1% sodium hydroxide for decolorization, and after decolorization, it was replaced with ion-exchanged water, filtered and dried.

  This bacterial cellulose membrane was pulverized, and pulp fibers (Nippon Paper Yufutsu LBKP) were added to the bacterial cellulose membrane at 25% and dispersed in ethanol. By filtering through a filter, a cellulose sheet in which pulp fibers were added to bacterial cellulose was prepared and dried. Thereby, the cellulose support 11 is formed.

  Next, 0.2 M of overbased acid tetrabutylammonium as an electrolyte was dissolved in a dimethyl sulfoxide solvent to prepare an electrolytic solution, and 10 mM of dimethyl terephthalate as an organic electrochromic compound was further dissolved therein. After this solution is soaked into the bacterial cellulose support 11, the display electrode substrate 15 on which the ITO electrode film to be the display electrode 14 is formed on the substrate 13, and the ITO electrode film to be the counter electrode 17 on the substrate 16 A display element was fabricated by sandwiching the counter electrode substrate 18 from both sides with the counter electrode substrate 18 formed with.

  When a negative electrode is connected to the display electrode 14 of this display element, a positive electrode is connected to the counter electrode 17, and a voltage of 4.5 V is applied by an electrochemical analyzer (BPS Corp., ALS660C), magenta is colored. did. On the other hand, when a voltage of −1.0 V was sufficiently applied, the magenta was decolored and turned white again.

(Comparative Example 1)
Next, Comparative Example 1 will be described.

  The display element in Comparative Example 1 is a display element produced by the same method using a material consisting only of bacterial cellulose for the cellulose support in the display element shown in Example 1. As a result of applying a voltage to the display element thus fabricated, a point defect that did not cause color development was confirmed although a color development reaction was observed in the display element. As described above, since the surface roughness of the support made only of bacterial cellulose is 3.8%, it is presumed that a point defect due to poor coloration occurred in a portion not in contact with the display electrode and the counter electrode. The

(Comparative Example 2)
Next, Comparative Example 2 will be described.

  The display element in Comparative Example 2 is a display element produced by the same method using a material obtained by adding 75% pulp fiber to bacterial cellulose to the cellulose support in the display element shown in Example 1. As a result of applying a voltage to the display element thus fabricated, a point defect that did not cause color development was confirmed although a color development reaction was observed in the display element. As described above, since the surface roughness of the support obtained by adding 75% pulp fiber to bacterial cellulose is 4.9%, there is a point defect due to poor coloring in the portion not in contact with the display electrode and the counter electrode. Presumed to have occurred.

(Example 2)
Next, Example 2 will be described. In the display element in Example 2, an electrolytic solution was prepared by dissolving 0.2 M of lithium perchlorate as an electrolyte in a propylene carbonate solvent, and 10 mM of silver iodide was further dissolved. This solution was used in Example 1. The display element was produced by soaking in the bacterial cellulose support 11. When a negative electrode was connected to the display electrode 14 of this display element, a positive electrode was connected to the counter electrode 17 and a voltage of 3.0 V was applied in the same manner as in Example 1, silver was deposited near the display electrode 14 and black. The color developed. On the other hand, when a voltage of −1.0 V was sufficiently applied, the black color returned to the original white state even when the color disappeared.

(Example 3)
Next, a third embodiment will be described. This example is the display element of the second embodiment.

  The display element in this example uses the cellulose support shown in Example 1, that is, the cellulose support 31 in which 25% of pulp fibers are added to bacterial cellulose, and an ITO film on one surface of the cellulose support 31. Was formed by DC sputtering to form the display electrode layer 33. The deposited ITO film was 100 nm, and the sheet resistance on the surface was 200 Ω / sq. In addition, an Au film was formed on the other surface of the cellulose support 31 by vacuum deposition to form a counter electrode layer 34. The film thickness of the formed Au film was 100 nm, and the sheet resistance on the surface was 3Ω / sq. After each of the display electrode layer 33 and the counter electrode layer 34 is connected to a copper wire, a part of the cellulose support is left, and an aqueous polyvinyl alcohol solution (Nippon Gosei Kagaku, Z-100) is applied as the electrolyte sealing layer 35 and dried by heating. did.

  Cellulose support from an area where the electrolyte sealing layer 35 is not formed by using an electrolyte in which 0.2 mM tetrabutylammonium perchlorate and dimethyl terephthalate 10 mM, which is an organic electrochromic compound to be the coloring material 32, are dissolved in dimethyl sulfoxide The display element was produced by making it soaked in 31 and again apply | coating polyvinyl alcohol aqueous solution to the whole surface.

  When the copper wire connected to the display electrode layer 33 is connected to the negative electrode, the copper wire connected to the counter electrode layer 34 is connected to the positive electrode, and a voltage of 4.5 V is applied by an electrochemical analyzer, the color changes to magenta. did. On the other hand, when a voltage of −1.0 V was sufficiently applied, the magenta was decolored and turned white again.

(Comparative Example 3)
Next, Comparative Example 3 will be described.

  The display element in Comparative Example 3 was prepared by using the cellulose support shown in Comparative Example 1, that is, the cellulose support made of only bacterial cellulose, by the same method as shown in Example 3. is there. At this time, the thickness of the ITO film serving as the display electrode layer was 100 nm, but the sheet resistance on the surface was 800 Ω / sq. When a voltage was applied to the display electrode layer and the counter electrode layer of the display element manufactured as described above, it was necessary to apply a voltage of 6.0 V in order to cause a color development reaction. In addition, point defects due to poor coloring that were not partially displayed were confirmed.

  Moreover, although the form which concerns on implementation of this invention was demonstrated, the said content does not limit the content of invention.

DESCRIPTION OF SYMBOLS 11 Cellulose support body 12 Color developing material 13 Substrate 14 Display electrode 15 Display electrode substrate 16 Substrate 17 Counter electrode 18

Special table 2001-510590 gazette JP 2002-328401 A JP 2004-151265 A JP 2006-106669 A

Claims (10)

A cellulose support obtained by adding pulp fibers to bacterial cellulose;
A display electrode formed on one surface of the cellulose support;
A counter electrode formed on the other surface of the cellulose support;
A color-developing material capable of reversibly changing color by an electrolyte contained in the cellulose support and a redox reaction;
A display element comprising:   The display element according to claim 1, wherein a content of pulp fibers with respect to bacterial cellulose in the cellulose support is less than 75%.   The display element according to claim 1, wherein a pore volume in the cellulose support is 0.4 mL / g or more.   The display element according to claim 1, wherein a color is generated or decolored in the color forming material by passing a current between the display electrode and the counter electrode.   The display element according to claim 1, wherein the color forming material contains an electrochromic compound.   The display device according to claim 1, wherein the cellulose support, the display electrode, and the counter electrode are covered with an electrolyte sealing layer.   The display element according to claim 6, wherein the electrolyte sealing layer has oil resistance.   A display element comprising a plurality of the display elements according to claim 1, wherein the coloring materials in the display elements emit different colors. Adding a pulp resin to bacterial cellulose to form a cellulose support;
Forming a display electrode on one surface of the cellulose support and forming a counter electrode on the other surface;
Impregnating the bacterial cellulose support with a chromogenic material capable of reversibly changing color by an electrolyte and a redox reaction;
A method for manufacturing a display element, comprising:   The method for manufacturing a display element according to claim 9, wherein the display electrode or the counter electrode is formed by sputtering or vacuum deposition of a transparent electrode material or a metal material.

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