JP2005115162A - Sheet type display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet-like display device using a film-like substrate, having a stable seal, and in which a spacer does not flow even when bent.
An auxiliary electrode (41c) for improving adhesion is provided between a transparent electrode (41a) and a seal member (42S), and a spacer (32S) is provided on a film substrate (41A) carrying the transparent electrode. The contact area is formed so as to have a shape smaller than the area in contact with the film substrate (41B) carrying the metal electrode (41b).
[Selection] Figure 5

Description

  The present invention generally relates to a sheet type display device, and more particularly to a sheet type display device in which a short circuit between electrodes is prevented by a spacer.

  2. Description of the Related Art Conventionally, a sheet type display device called an electronic paper, a paper-like display, a digital paper, or the like, which displays an image by changing optical absorption or reflection by an electric field has been proposed.

  As a display device that changes optical absorption and reflection by an electric field, a display device using a microcapsule enclosing rotating particles combined with hemispheres having different colors and electrical characteristics together with an insulating liquid, A liquid crystal / polymer composite film containing a dichroic dye and a smectic liquid crystal using a microcapsule in which the solvent in which the electrophoretic particles are dispersed is colored like the one described in JP-86116 There are things used. These sheet-type display devices have memory properties, can hold image information without a power source, and are reflection-type display devices, and thus are expected as an alternative to paper. In these display devices, since the display element may be applied on a PET film having electrodes, the sheet display device is thin, light, and flexible.

  In addition, an ECD type display device using an electrochromic phenomenon has been developed.

  In general, an ECD type display device uses a phenomenon in which a coloring material and an electrolyte are sandwiched between a transparent electrode and a counter electrode, and the coloring material is colored by an electrochemical reaction by passing an electric current. Even after turning off, the color is not erased. When the color is erased, a similar electrochemical reaction is caused by flowing a current in the opposite direction. The ECD type display device provides excellent contrast.

  In recent years, as one of the ECD type display devices, an electrodeposition (EDD) type display device capable of realizing paper-like contrast and whiteness has been proposed.

  In this EDD type display device, as described in U.S. Pat. Nos. 4,540,716 and 4,540,717, silver halide is dissolved in a solution together with a supporting electrolyte containing halogen. Then, an electric current is passed through the electrolyte to cause an electrochemical reaction to deposit on the transparent electrode to obtain a desired color. When erasing the color, silver on the transparent electrode is redissolved by applying a reverse current.

  Further, as described in JP-A-11-101994, a white porous background plate is used in combination with this electrolytic solution, or as described in JP-A-2002-258327. The proposal has been made to increase the reflectance and whiteness of the background portion and improve the contrast by using a solid electrolyte in which a white inorganic pigment is dispersed.

  In order to improve the response speed of the ECD type display device, Japanese Patent Laid-Open No. 59-90820 proposes a configuration using auxiliary electrodes.

  Among these conventional sheet type display devices, when the display element is a liquid such as liquid crystal, sol or gel, bead-shaped particles are used to keep the distance between the transparent electrode and the counter electrode constant and prevent short circuit. And spacers molded into a cylindrical shape are dispersed in the element.

  FIG. 1 shows the principle of an ECD type display device 10.

  Referring to FIG. 1, in the ECD type display device 10, a pair of film substrates 11 </ b> A and 11 </ b> B are disposed so as to sandwich an electrolyte layer 12, and contact the electrolyte layer 12 among the film substrates 11 </ b> A and 11 </ b> B. Electrode layers 11a and 11b are formed on the surface on the side.

One of the electrode layers 11a and 11b is made of a transparent electrode such as ITO, and a display layer 13 that causes an electrochemical reaction such as WO ₃ is formed on the surface of the transparent electrode, for example, the electrode layer 11a.

Therefore, by driving the electrode layers 11a and 11b, the display layer 13 exchanges electrons with the electrolyte layer 12 to change the state. As the state changes, the reflectance of the display layer 13 also changes, and a desired display is made by this change in reflectance. Note that a white pigment such as TiO ₂ is added to the electrolyte layer 12 in order to improve the reflectance.

  FIG. 2 shows the principle of the EDD type display device 20.

  Referring to FIG. 2, in the EDD type display device 20, a pair of film substrates 21 </ b> A and 21 </ b> B is disposed so as to sandwich the electrolyte layer 22, and contacts the electrolyte layer 22 among the film substrates 21 </ b> A and 21 </ b> B. Electrode layers 21a and 21b are respectively formed on the surface on the side.

  One of the electrode layers 21a, 21b, for example, the electrode layer 21b is made of a transparent electrode such as ITO, while the electrolyte layer 22 contains silver halide.

  Therefore, when the electrode layers 21a and 21b are driven, a redox reaction of silver occurs on the surface of the electrode layer 21b, and silver is deposited on the electrode layer 21b. When the electrode layers 21a and 21b are driven with reverse polarity, the silver previously deposited on the electrode layer 21b is dissolved in the electrolyte layer 22.

  The silver deposited on the electrode layer 21b has a low reflectivity and a black appearance, which enables a desired display.

As described above, it should be noted that the display on the EDD type display device 20 is performed by the oxidation-reduction reaction that occurs on the surface of the transparent electrode, similarly to the ECD type display device.
JP-A-2-96119 JP 2003-107533 A Japanese Patent Laid-Open No. 7-17090 JP 2000-338506 A JP-A-56-22413

  By the way, in such a sheet type display device, in order to perform a so-called paper-like display similar to the display on ordinary paper, in order to bend the display device, flexible polyethylene terephthalate (PET), polyethylene It is necessary to use a film base material such as phthalate (PEN) or polycarbonate (PC) as a substrate, and an electrode is formed by depositing an ITO film or a metal film on such a film substrate.

  However, in such a conventional flexible sheet type display device, (1) distortion caused by the bending of the substrate is applied to a sealing member provided so as to seal the electrolyte layer in contact with the electrode layer. The problem that the member is destroyed, (2) The problem that the coating property of the ITO film used as the transparent electrode is low and the adhesion between the sealing member and the transparent electrode is low, and (3) Further, the adhesion of the sealing member In relation to the low value, the electrolyte solution constituting the electrolyte display layer permeates into the gap between the transparent electrode and the seal member, causing problems such as easy peeling of the seal member.

  Moreover, since the resin film which comprises a base material cannot be heated at the time of ITO film-forming, it has problems, such as it being difficult to produce a transparent electrode with low resistance and high transmittance.

  In particular, in an ECD type display device including an EDD type, display is performed by an electrochemical reaction. Therefore, the transparent electrode is required to have a low resistance so as to improve the response speed as much as possible. Moreover, since such an ECD type display device is a reflective display element, the transparent electrode is required to have a high transmittance in order to obtain a high reflectance and a high contrast. In the prior art, it has been difficult to satisfy these requirements.

  3A and 3B are a plan view and a cross-sectional view showing a schematic configuration of a conventional sheet type display device 30, respectively. 3A and 3B includes the ECD type or EDD type device shown in FIGS.

  Referring to FIGS. 3A and 3B, the sheet type display device 30 includes a flexible substrate 31A made of a transparent film carrying a transparent electrode film 31a and a flexible board made of a film carrying a metal electrode film 31b. An electrolyte layer 32 is sealed between the substrates 31A and 31B by a sealing member 31C provided along the outer periphery of the substrate between the substrates 31A and 31B.

  3A and 3B, external light is incident through the substrate 31A and reflected by the white pigment dispersed in the electrolyte layer 32. At this time, the surface of the transparent electrode 31a is reflected. It is modulated by a redox reaction in the vicinity.

  As described above, as the substrates 31A and 31B, film base materials such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polycarbonate (PC) having flexibility are used. On the other hand, the sealing member As 31C, an olefin-based heat-sealing sheet is used. An ITO film is used as the transparent electrode film 31a.

  In such a configuration, excellent adhesion can be obtained between the seal member 31C and the metal electrode film 31b. However, the adhesion between the ITO electrode film 31a and the seal member 31C is wettability on the surface of the ITO film. Therefore, when the substrates 31A and 31B are bent, a gap is generated between the ITO electrode film 31a and the sealing member 31C, and the electrolyte constituting the electrolyte layer 32 can enter the gap. There is sex. When the electrolytic solution enters such a gap, peeling of the sealing member 31C starts from that portion.

  Further, since the transparent electrode 31a is formed on the film substrate 31A, it cannot be formed at a temperature at which the ITO film crystallizes. Therefore, in such a sheet type display device, the transparent electrode 31a has a high resistance value. Indicates. Since the ECD type or EDD type sheet type display device is a current-driven type device that performs display using an electrochemical reaction, the resistance of the transparent electrode film 31a has a serious effect on the display speed. This problem becomes particularly serious when heating or pressurization is performed to cure the sealing member.

  Incidentally, in the conventional sheet type display device, as shown in FIG. 3B, a spherical or columnar spacer 32S is provided between the substrate 31A and the substrate 31B, and the thickness of the electrolyte layer 12 is maintained constant. However, when the substrate is bent, there arises a problem that these spacers 32S flow or fall down. As described above, when the spacer 32S flows in the electrolyte layer 12, the thickness of the electrolyte layer 12 varies, the image is disturbed, or a short circuit occurs between the electrodes, and the display device is destroyed. There is a risk. In particular, in the case of a display device that requires a certain thickness of the electrolyte layer in order to maintain the whiteness of display, such as an ECD type display device, the problem of spacer flow caused by bending of the substrate is very serious. .

  SUMMARY OF THE INVENTION Accordingly, it is a general object of the present invention to provide a new and useful sheet type display device that solves the above problems.

  The present invention provides a sheet-type display device in which the coloring state is changed by an electrochemical reaction on an electrode, and includes a first substrate having a transparent electrode and a first substrate facing the first substrate. Two substrates, an electrolyte layer held between the first and second substrates, and a sealing member between the first and second substrates and holding the electrolyte, and the transparent electrode An auxiliary electrode is provided between the sealing member and the transparent electrode is brought into contact with the sealing member via the auxiliary electrode.

  The present invention also solves the above-described problems by providing a transparent first substrate having a transparent electrode, a second substrate disposed so as to face the first substrate via a spacer, the first and In a sheet type display device comprising a display layer sandwiched between second substrates, the spacer has a shape in which an area in contact with the first substrate is smaller than an area in contact with the second substrate. This is solved by a sheet type display device characterized by having.

  According to the present invention, there is provided a sheet-type display device in which a coloring state is changed by an electrochemical reaction on an electrode, the first substrate having a transparent electrode, and the second substrate facing the first substrate. In the sheet type display device, comprising: a substrate; an electrolyte layer held between the first and second substrates; and a seal member that holds the electrolyte between the first and second substrates. An auxiliary electrode is provided between the transparent electrode and the seal member, and the transparent electrode is configured to be in contact with the seal member via the auxiliary electrode, whereby the adhesion of the seal member is improved and displayed. Even when the device is bent, problems such as breakage or peeling of the sealing member or leakage of the electrolyte can be avoided.

  According to the invention, a transparent first substrate having a transparent electrode, a second substrate disposed so as to face the first substrate via a spacer, and the first and second substrates In the sheet type display device comprising the display layer sandwiched between the substrates, the spacer has a shape in which the area in contact with the first substrate is smaller than the area in contact with the second substrate With this configuration, even when the display device is bent, it is possible to avoid the problem that the spacer flows or falls, and accompanying this, the image is distorted or a short circuit occurs between the electrodes, and the display device is destroyed. The problem of being done is avoided.

[First Embodiment]
4A and 4B are a plan view and a cross-sectional view, respectively, showing a schematic configuration of the sheet type display device 40 according to the first embodiment of the present invention.

  Referring to FIG. 4A, the sheet type display device 40 is an ECD type display device, and includes a flexible substrate 41A made of a transparent film carrying a striped transparent electrode film 41a, and the transparent electrode 41a. A flexible substrate 41B made of a film carrying orthogonal stripe-shaped metal electrode films 41b is included, and a solid electrolyte layer 42 is provided between the substrates 41A and 41B along the outer periphery of the substrate between the substrates 41A and 41B. The sealing member 41C is sealed.

  In the example of FIGS. 4A and 4B, external light is incident through the substrate 41A and reflected by the white pigment dispersed in the solid electrolyte layer 42. At that time, the transparent electrode 41a is modulated by a redox reaction in the vicinity of the surface.

  As described above, as the substrates 41A and 41B, film base materials such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polycarbonate (PC) having flexibility are used. On the other hand, the sealing member As 41C, an olefin-based heat sealing sheet is used. As the transparent electrode film 41a, an ITO film patterned by etching in a stripe shape is used.

  5A and 5B are diagrams showing the configuration of the substrate 41A in FIGS. 4A and 4B in more detail.

  Referring to FIGS. 5A and 5B, on the transparent electrode pattern 41a formed on the substrate 41A, a metal is deposited on the contact portion with the seal member 42S, or a conductive material containing the metal. The auxiliary electrode 41c is formed by applying a conductive polymer.

  When the auxiliary electrode 41c is made of metal, Al, Pt, Ag, Au, Cu, Cr, Ti, W, Fe, Ni, Mg, Zn, Sn, Pd, and the like can be used. It can be used alone or in the form of a plurality of alloys. At this time, the film thickness may be in the range of 10 to 300 nm, and can be formed using a known film formation method such as vapor deposition or sputtering.

  Further, the auxiliary electrode 41c is prepared by dispersing the above-described metal in a polymer and dissolving it in a known solvent such as butyl acetate, toluene, ethyl acetate, acetone, xylene, etc. It is also possible to make it. In addition, as said polymer, well-known materials, such as an acryl, a polyurethane, an epoxy, a polystyrene, can be used.

  The auxiliary electrode 41c needs to be patterned so as not to short-circuit the transparent electrode 41a. As this patterning method, (1) a metal film is uniformly deposited on the transparent electrode and then etched. Examples include a method of depositing ITO and a metal film on the film substrate 41A using a mask, and (3) a method of screen printing a conductive paste on the substrate 41A. However, the present invention is not limited thereto. Absent.

  The auxiliary electrode 41c needs to cover at least the adhesive surface of the sealing member 42S of the transparent electrode 41a, and preferably covers the connecting portion 41aT formed at the end of the transparent electrode 41a in a stripe shape. Is preferred.

  As the seal member 42S, a known material such as a heat fusion resin such as polyolefin or polyester, a thermosetting resin such as epoxy, or a photocurable resin such as acrylic can be used. In particular, from the viewpoint of solvent resistance and heat resistance, it is preferable to use a heat-sealing resin made of polyolefin or crystalline polyester, or a two-component epoxy adhesive. If a spherical spacer is mixed with the seal member 42S, the gap between the counter electrodes 41a and 41b can be controlled.

  As the transparent electrode 41a, a known transparent conductive material such as IZO and GZO can be used in addition to the ITO, and the substrates 41A and 41B include PET, PEN, PC, acrylic resin, epoxy resin, and the like. These known materials can be used as appropriate.

  As the solid electrolyte layer 42, a polymer impregnated with an electrolytic solution prepared by adding silver halide, a supporting electrolyte or the like to an organic solvent in a polymer is used.

  As silver halide, silver fluoride (AgF), silver chloride (AgCl), silver bromide (AgBr), silver iodide (AgI), or the like can be used. It is desirable to use silver iodide from the viewpoint of solubility. The silver halide concentration is preferably 0.05 to 2.0 mol / l.

  The supporting electrolyte containing halogen used for dissolving silver halide includes ammonium iodide, tetraethylammonium iodide, potassium iodide, potassium bromide, potassium chloride, sodium iodide, sodium bromide, sodium chloride, Known materials such as lithium iodide, lithium bromide, and lithium chloride can be used. In the case of an EDD type display device, an ammonium salt is preferably used from the viewpoint of display speed and silver halide solubility. The supporting electrolyte is in the range of 0.5 to 2 times the silver halide concentration.

  Examples of other supporting electrolytes include known materials such as perchlorate, thiocyanate, and sulfate such as tetrabutylammonium perchlorate, tetraethylammonium perchlorate, isocyanate thiocyanate, and sodium sulfide. .

  Furthermore, as solvents for dissolving these silver halides and supporting electrolytes, dimethylformamide (DMF), dimethylsulfoxide (DMSO), diethylformamide (DEF), N, N-dimethylacetamide (DMAA), N-methylpropionic acid amide ( MPA), N-methylpyrrolidone (NMP), propylene carbonate (PC), ethylene carbonate (EC), acetonitrile (AN), 2-ethoxyethanol (EEOH), 2-methoxyethanol (MEOH), dimethyl sulfoxide (DMSO), Dioxolane (DOL), ethyl acetate (EA), tetrahydrofuran (THF), methyltetrahydrofuran (MeTHF), dimethoxyethane (DME), γ-butyrolactone (GBL), etc. can be used. It may be mixed. From the viewpoint of conductivity and solubility, it is desirable to use dimethyl sulfoxide, dimethylformamide, diethylformamide, or dimethylacetamide.

  Moreover, in order to accelerate | stimulate melt | dissolution of silver, you may add an oxalic acid, a fumaric acid, a maleic acid, etc. suitably.

  As the polymer used for the solid electrolyte layer 42, known polymer materials such as polyacrylonitrile, polyvinylidene fluoride, polyvinyl pyrrolidone, polyethylene oxide, ethyl cellulose, cyanoresin, polystyrene, and acrylic can be used. The amount of the polymer is desirably 2 to 10 wt% with respect to the electrolytic solution.

  A pigment is added to the solid electrolyte layer 42 to improve contrast. Examples of the pigment include silicon dioxide, calcium carbonate, and aluminum oxide in addition to the titanium dioxide described above. From the viewpoint of rate, it is desirable to use titanium dioxide. The pigment concentration is preferably about 5 to 20 wt% with respect to the solid electrolyte.

  Further, spacers similar to the spacers 32S of FIG. 3 are dispersed in the electrolyte layer 42. Examples of such spacers include crosslinkable polymers (polystyrene, acrylic, etc.), wax-like substances, inorganic particles (zirconia, glass). Etc.) which are not known to be dissolved in the electrolytic solution can be used.

  Further, by forming the electrode 41b with silver, the density during color development can be increased. Further, by making the film thickness of the silver electrode greater than 0.2 μm, it is possible to obtain a uniform color.

An ITO film (OTEC-130 manufactured by Oji Tobi) having a sheet resistance of 30Ω / □ was formed on a substrate 41A made of a PET film having a thickness of 188 μm, and a Cr film having a thickness of 100 nm was formed on the ITO film by sputtering. A film was formed. Further, this Cr film is etched to be patterned into a line and space pattern having a line width of 290 μm and a space of 30 μm to form a stripe electrode 41a, and a Cr auxiliary electrode 41c is further formed on the stripe electrode 41a from the electrode connection portion 41aT. It formed so that it might extend to the formation area of the sealing member 42S.
In Example 1, a stripe electrode having a Cr / Ag structure formed by laminating Cr and Ag was used as the counter electrode 41b.

  In Example 1, a heat-sealing film (Toyobo's Byron GA-6400) made of crystalline polyester on the Cr / Ag stripe electrode 41b side, that is, the substrate 41B, was used as the sealing member 42S at a temperature of 95 ° C. Next, silver iodide (0.2 mol / l), ammonium iodide (0.1 mol / l), and oxalic acid (0.1 mol / l) were dissolved in propylene carbonate to prepare an electrolytic solution. 0.6 g of an acrylate monomer (Shin Nakamura Chemical 701) is dissolved in 3.2 g of the electrolytic solution, and a polymerization initiator (Wako Pure Chemical V-65) is dissolved in propylene carbonate at a concentration of 2.5 wt%. Further, titanium dioxide was dispersed at a rate of 5 wt%. Further, cyanoethylated pullulan was dissolved as a polymer and mixed with a stirrer for 3 minutes. Further, 0.006 g of a spacer (Micropearl SP-250 manufactured by Sekisui Chemical Co., Ltd.) was mixed therewith to produce an ink-like electrolyte solution.

  The ink electrolyte is dropped into a frame formed by a sealing member 42S made of a heat-sealing film on the substrate 41A, and then a substrate 41A carrying a striped ITO electrode 41a on which the Cr film 41c is deposited. Was fused. In this state, polymerization was performed at 80 ° C. for 30 minutes to form a solid electrolyte, and the display device 40 was produced.

  When a drive voltage of -1.2 V is applied to the ITO electrode 41a of the display sheet thus produced, Ag is deposited on the electrode, and a display with a maximum reflectance of 70% and a contrast ratio of 18 can be realized. confirmed.

  A character pattern shown in FIG. 6 was formed on an ITO film (Teijin HT200-B60) having a sheet resistance of 30Ω / □ formed on a polycarbonate substrate 41A by etching.

  Further, a conductive silver paste was applied on the ITO electrode 41a surrounding the character pattern so as to have a thickness of 10 μm. On the other hand, an electrode 41b was formed on the counter substrate 41B by stacking a Cr film and an Ag film. Further, a sealing member 42S was formed on the substrate 41B by fusing a heat-sealing film made of crystalline polyester (Kurabo Clanbetter A-1510) at a temperature of 125 ° C.

  Further, silver iodide (0.2 mol / l), ammonium iodide (0.1 mol / l), and oxalic acid (0.1 mol / l) were dissolved in propylene carbonate to prepare an electrolytic solution. 0.6 g of an acrylate monomer (Shin Nakamura Chemical 701) was dissolved in 3.2 g of the electrolytic solution. Further, 2.5 wt% of a polymerization initiator (V-70 manufactured by Wako Pure Chemical Industries) was dissolved in propylene carbonate, and titanium dioxide was dispersed at a ratio of 5 wt%. Further, cyanoethylated pullulan was dissolved as a polymer and mixed with a stirrer for 3 minutes. Furthermore, 0.006 g of a spacer (Sekisui Chemical Micropearl SP250) was mixed to prepare an ink-like electrolyte.

  This ink-like electrolytic solution was dropped on the substrate 41B in a frame formed by a heat-sealing seal member 42S, and the substrate 41A carrying the ITO film 41a on which the Cr film 41c was deposited was fused. In this state, polymerization was performed at 50 ° C. for 30 minutes to form a solid electrolyte, and a sheet-like display device 40 was produced.

It was confirmed that when a drive voltage of -1.2 V was applied to the ITO electrode 41a of the manufactured display device 40, silver was deposited on the electrode 41a and a display with a maximum reflectance of 73% and a contrast ratio of 25 could be realized. It was done.
[Comparative Example 1]
In Example 1, a display sheet was similarly produced except for the step of laminating a Cr film on the ITO film. In this comparative example, although the display occurred with the application of voltage, it was observed that the adhesive strength of the seal member 42S was low and peeling occurred with the bending.
[Comparative Example 2]
In Example 2, a display sheet was produced in the same manner except for the step of laminating a silver paste on the ITO film. In this case, it was confirmed that the sheet resistance of the ITO film increased from 30Ω / □ to 100Ω / □ or more with heating at the time of adhesion, and no display was generated even when a voltage was applied.

  As described above, in the first embodiment of the present invention, the auxiliary electrode 41c is interposed between the transparent electrode 41a and the seal member 42S, so that the transparent electrode 41a and the seal member 42S are reliably joined to each other. Even when the apparatus is bent, the sealing member 42S does not peel off, and the electrolyte does not leak out.

This feature of the first embodiment of the present invention can also be applied to the second embodiment of the present invention described below.
[Second Embodiment]
FIG. 7A is a cross-sectional view showing a configuration of a sheet-like display device 60 according to the second embodiment of the present invention. However, in FIG. 7A, portions corresponding to the portions described above are denoted by the same reference numerals, and description thereof is omitted.

  Referring to FIG. 7A, the display device 60 is an EDD type display device, but has a cross-sectional configuration similar to that of the ECD type display device shown in FIG. However, in the display device 30, a liquid or gel electrolyte solution containing silver salt (silver halide or the like) is used as the electrolyte layer 42, and it dissolves in the electrolyte by passing a driving current between the electrodes 41 a and 41 b. The display is performed by precipitating or re-dissolving silver.

  In addition to the silver salt, the electrolyte solution contains ammonium iodide, tetraethylammonium iodide, potassium iodide, potassium bromide, potassium chloride, sodium iodide, sodium bromide, sodium chloride, lithium iodide, odor as a supporting electrolyte. Lithium chloride, lithium chloride, tetrabutylammonium perchlorate, tetraethylammonium perchlorate, isocyanates thiocyanate, sodium sulfide and other perchlorates, thiocyanates, sulfates, etc. Solvents to be dissolved include dimethylformamide (DMF), dimethylsulfoxide (DMSO), diethylformamide (DEF), N, N-dimethylacetamide (DMAA), N-methylpropionic acid amide (MPA), N-methylpyrrolidone (NMP) , Propire Carbonate (PC), acetonitrile (AN), 2-ethoxyethanol (EEOH), 2-methoxyethanol (MEOH), dimethyl sulfoxide (DMSO), dioxolane (DOL), ethyl acetate (EA), tetrahydrofuran (THF), methyltetrahydrofuran (MeTHF), dimethoxyethane (DME), γ-butyrolactone (GBL) and the like, or a mixture thereof. Moreover, in order to accelerate | stimulate melt | dissolution of silver, you may add suitably additives, such as an oxalic acid, a fumaric acid, and a maleic acid.

  Furthermore, in order to make these into a gel, monomers such as polyethylene oxide derivatives may be polymerized in the solution, or those previously polymerized may be dissolved in the solution.

  In order to improve contrast, titanium dioxide, silicon dioxide, calcium carbonate, aluminum oxide, or the like may be added as a white pigment.

  As the transparent electrode 41a, an ITO film deposited on a transparent substrate 41A is used as in the previous embodiment. As the transparent substrate 41A, glass, polyethylene terephthalate, polycarbonate, polyolefin, or the like formed into a film can be used. The same substrate material can be used for the counter substrate 41B, but Ag is vapor-deposited on the substrate 41B as an electrode pattern 41b.

  In the present invention, a hemispherical spacer 42s shown in FIG. 7A is seated on the substrate 41B carrying the Ag electrode pattern 41b, and the bottom surface of the spacer 42s is seated on the substrate 41B or the Ag electrode pattern 41b on the substrate 41B. To fix.

  More specifically, a chip-like thermoplastic resin is spread on the substrate 41B, and the Ag electrode film 41b is heated together. As a result, the chip-like resin is thermally melted and bonded to the surface of the substrate 41B or the Ag electrode film 41b, and is rounded by its own surface tension to form a hemispherical spacer 42s. As such a thermoplastic resin, resins such as polyester, polystyrene, polypropylene, polyethylene, and polyacryl can be used. In particular, the glass transition temperature Tg is desirably lower than the softening point of the resin film constituting the substrate 41B. . In the EDD type display device, since a polar solvent is often used for the electrolytic solution, it is desirable to use a polyolefin resin that is not easily attacked by the solvent as the spacer 42s. Further, not only heat but also a resin curable with ultraviolet rays may be used.

  As another method, a conical or wedge-shaped mold shown in FIGS. 7B and 7C may be placed, and the resin may be printed and cured in this state.

Although the dimension of the spacer 42s differs depending on the thickness h of the electrolyte layer 42, when the maximum side or diameter L of the contact portion with the substrate 41A is 1 / L ≦ 1, the adhesion of the spacer is stabilized. At this time, the area of the upper part of the spacer that contacts the transparent substrate is preferably 0.005 mm ² or less in order to make it difficult to see.

  After patterning the Ag film 41b in a stripe pattern, the substrate 41A and the substrate 41B thus manufactured are joined via the seal member 42S as described in the previous embodiment, and the electrolyte solution is put in this gap. After pouring, the sheet type display device is manufactured by sealing while defoaming.

  According to the present invention, not only in the case of a sheet type display device having a thickness of 20 μm, but also in the case where the thickness of the sheet type display device is 200 μm, the distance between the electrodes can be kept constant and a short circuit between the electrodes can be prevented. .

  In this example, a polyethylene film having a thickness of 188 μm on which a transparent electrode 41a and an Ag electrode film 41b were deposited was used as the substrates 41A and 41B.

  The substrate 41B is temporarily fixed on a glass plate, a 120 μm square polyolefin resin chip is spread on the Ag electrode film 41b on the substrate 41B, and placed in a constant temperature bath at 120 ° C. for 3 minutes. As shown in FIG. 1, a hemispherical spacer 42s having a radius of about 100 μm was formed.

  In this example, the electrolytic solution was further mixed in a mixed solvent of dimethylacetamide and dimethylsulfoxide (ratio 7: 3), silver iodide (0.15 mol / l), ammonium iodide (0.15 mol / l), perchloric acid. It was prepared by dissolving tetra-n · butylammonium (0.15 mol / l) and oxalic acid (0.18 mol / l).

  To 3.8 g of this electrolytic solution, 0.2 g of a monomer (tricyclodecane dimethanol diacrylate) is dissolved, and further, a polymerization initiator (2,2- A solution in which 2.5 wt% of azobis-isobutyronitrile) was dissolved was mixed, and titanium dioxide (CR-95) was dispersed at a rate of 5%.

  The film substrate 41B carrying the Ag electrode film 42b is arranged to face the film substrate 41A carrying the transparent electrode 41a through the spacer 42s, and the outer periphery of the substrate is a heat-sealing film (Crambetter A-1510: Adhering with a sealing member 42S having the same shape as described in the previous embodiment.

  Further, an opening is formed in a part of the seal member 42S, and the dispersion is injected into the gap between the substrates 41A and 41B through the opening and sealed, and then at a temperature of 100 ° C. under a nitrogen atmosphere. The sheet type display device was produced by heating for a minute.

In this display device, a black voltage is displayed by applying a driving voltage of -1.2V to the ITO electrode 41a for 10 seconds, and then the display is decolored by applying a voltage of + 0.5V for 10 seconds. Even if the display surface was observed closely, the influence on the display of the spacer 42s could not be recognized. Furthermore, even if this sheet type display device is bent, the display image is not disturbed. After that, the test was repeated 100 times or more by combining the display / decoloring operation and the bending of the display device, but the display performance was changed. There wasn't.
[Comparative Example 1]
In the configuration of Example 3, a 100 μm square polyolefin resin chip was brought into close contact with the Ag electrode 41b, and a display experiment was conducted in the same manner. As a result, it was confirmed that the spacer was visible and the display was affected. From this experiment, it was confirmed that the spacer was visually recognized unless the area of the portion in contact with the transparent electrode 41a in the spacer 42s was at least 70 μm square or less.
[Comparative Example 2]
In the configuration of Example 3, when a spacer having a bottom area of 490 μm (one side is 70 μm) and a height of 100 μm was used as the spacer 42s on the Ag electrode 41b, the bending test of the completed display device was performed during electrolyte injection. It was confirmed that the electrode 42 was short-circuited due to the spacer 42s being detached from the electrode at the time, and so on, and many portions that could not be displayed were generated.

  As described above, according to the second embodiment of the present invention, the spacer 42s has a shape in which the area in contact with the film substrate 41A is smaller than the area in contact with the film substrate 41B. Even when the apparatus is bent, stable display can be realized.

The feature of the second embodiment of the present invention is not limited to the EDD type display device, but can also be applied to the ECD type display device described in the first embodiment.
(Appendix 1)
A sheet-type display device in which a coloring state changes due to an electrochemical reaction on an electrode,
A first substrate having a transparent electrode;
A second substrate facing the first substrate;
An electrolyte layer held between the first and second substrates;
A seal member between the first and second substrates for holding the electrolyte;
An auxiliary electrode is provided between the transparent electrode and the seal member,
The sheet-type display device, wherein the transparent electrode is in contact with the seal member via the auxiliary electrode.
(Appendix 2)
The auxiliary electrode is made of a metal containing one or more elements selected from the group consisting of Al, Pt, Ag, Au, Cu, Cr, Ti, W, Fe, Ni, Mg, Zn, Sn, and Pd. The sheet type display device according to appendix 1.
(Appendix 3)
The sheet type display device according to appendix 1, wherein the auxiliary electrode is made of a conductive polymer including a conductive powder and a polymer.
(Appendix 4)
The transparent electrode forms a striped electrode on the first substrate, and the auxiliary electrode takes out the electrode from the portion covered with the seal member to the outside of the seal member. The sheet-type display device according to Supplementary Note 1 or 2, wherein the sheet-type display device extends continuously to a portion.
(Appendix 5)
5. The sheet type display device according to claim 1, wherein the transparent electrode is in contact with a white solid electrolyte in a display region surrounded by the seal member.
(Appendix 6)
A transparent first substrate having a transparent electrode;
A second substrate disposed to face the first substrate via a spacer;
In a sheet type display device comprising a display layer sandwiched between the first and second substrates,
The sheet type display device, wherein the spacer has a shape in which an area in contact with the first substrate is smaller than an area in contact with the second substrate.
(Appendix 7)
The sheet type display device according to appendix 6, wherein the spacer has an area in contact with the first substrate of 0.05 mm ² or less.
(Appendix 8)
The sheet type display device according to appendix 6 or 7, wherein the spacer is fixed to the second substrate.
(Appendix 9)
The sheet type display device according to any one of appendices 6 to 8, wherein the first and second substrates are made of a flexible film.
(Appendix 10)
10. The sheet type display device according to any one of appendices 6 to 9, wherein the display layer is a solid or liquid that has ionic conductivity and develops color by an electrochemical reaction.

It is a figure explaining the principle of an ECD sheet type display device. It is a figure explaining the principle of an EDD type sheet type display device. (A), (B) is a figure which shows schematic structure of the conventional sheet type display apparatus. (A), (B) is a figure which shows the structure of the sheet type display apparatus by the 1st Embodiment of this invention. (A), (B) is a figure which shows a part of sheet-type display apparatus by the 1st Embodiment of this invention in detail. It is a figure which shows the example of the sheet type display apparatus by the 1st Embodiment of this invention. (A)-(C) are figures which show the structure of the sheet type display apparatus by the 2nd Embodiment of this invention.

Explanation of symbols

10, 20, 30, 40, 60, 80, 100 Sheet type display device 11A, 11B, 21A, 21B, 31A, 31B, 41A, 41B Film substrate 11a, 21a, 31a, 41a Transparent electrode 11b, 21b, 31b, 41b Electrode 12, 22, 32, 42 Electrolyte layer 13 WO ₃ film 31C, 42S Seal member 32s, 42s, 42s ₁ , 42s ₂ Spacer 41c Auxiliary electrode 41aT Terminal connection part

Claims (5)

A sheet-type display device in which a coloring state changes due to an electrochemical reaction on an electrode,
A first substrate having a transparent electrode;
A second substrate facing the first substrate;
An electrolyte layer held between the first and second substrates;
A seal member between the first and second substrates for holding the electrolyte;
An auxiliary electrode is provided between the transparent electrode and the seal member,
The sheet-type display device, wherein the transparent electrode is in contact with the seal member via the auxiliary electrode.   The auxiliary electrode is made of a metal containing one or more elements selected from the group consisting of Al, Pt, Ag, Au, Cu, Cr, Ti, W, Fe, Ni, Mg, Zn, Sn, and Pd. The sheet type display device according to claim 1.   The sheet type display device according to claim 1, wherein the auxiliary electrode is made of a conductive polymer including a conductive powder and a polymer.   The transparent electrode forms a striped electrode on the first substrate, and the auxiliary electrode takes out the electrode from the portion covered with the seal member to the outside of the seal member. The sheet type display device according to claim 1, wherein the sheet type display device extends continuously to a portion. A transparent first substrate having a transparent electrode;
A second substrate disposed to face the first substrate via a spacer;
In a sheet type display device comprising a display layer sandwiched between the first and second substrates,
The sheet-type display device, wherein the spacer has a shape in which an area in contact with the first substrate is smaller than an area in contact with the second substrate.

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