JP2011064976A - Display medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display medium that ensures rigidity without degrading display characteristics as compared to a display medium having a coating member for coating a display area. <P>SOLUTION: The display medium 110 includes a pair of flexible substrates 10 and 20 that are disposed facing each other, a display layer 50 laminated between the pair of flexible substrates, and bending suppression means for suppressing bending of the substrates which is disposed only in a non-display region of at least one of the pair of flexible substrates. The bending suppression means is, for example, rod-shaped member 60A and 60B stuck on one of the substrates, or a hollow part, a convex part or a waveform part formed on one of the substrates. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a display medium.

In recent years, various flexible display media using a liquid crystal, an organic electroluminescence element, or the like have been developed. Such a display medium uses, for example, a pair of flexible substrates in which a transparent electrode pattern such as ITO (indium tin oxide) is formed on a resin film, and the surface on which each electrode is formed faces inward. The display layer is sandwiched between the opposing electrodes.
For example, optical writing type electronic paper can be attached to and detached from a writing device. As shown in FIG. 8, a flexible substrate in which transparent electrodes 3 and 4 are formed on resin films 1 and 2 having optical transparency, respectively. A display layer in which a photoconductive layer 5 made of an organic photoconductive material, a light-shielding layer 7 and a liquid crystal layer 6 made of a liquid crystal display material are stacked is sandwiched therebetween. In the optical writing type electronic paper 100 having such a configuration, when light is irradiated from the substrate 1 on the photoconductive layer 5 side while applying a voltage to the transparent electrodes 3 and 4 on the front and back sides, the intensity of the light is instantaneously changed to the liquid crystal layer. 6 is converted to a reflection density of 6, and an image is displayed on the substrate 2 side.

Electronic paper in which the thickness of the resin film 1 or 2 is increased and electronic paper in which an anisotropic conductive layer (member) is inserted between the resin films 1 and 2 have been proposed (see Patent Document 1).
As shown in FIG. 8, it has been proposed to secure rigidity by covering the electronic paper main body with covering members 8 and 9 such as a cover sheet.

  For example, a thin plate-shaped electronic paper main body, an exterior film (covering member) formed by laminating an inorganic water vapor barrier film on a thermoplastic film substrate, and covering the electronic paper main body by thermocompression bonding; There has been proposed an electronic paper including a stress relieving portion that relieves stress generated in an exterior film when the paper body is in close contact with the peripheral corner portion (see Patent Document 2). In addition, a flexible display medium and a display medium cover (covering member) are housed in a casing in a state of being wound by a leaf spring, and the display medium and the display cover are pulled out of the casing and used by the leaf spring in use. A fixed display device has been proposed (see Patent Document 3).

JP 2001-92387 A JP 2008-275684 A Special table 2008-530611 gazette

  An object of the present invention is to provide a display medium that secures rigidity without deteriorating display characteristics as compared with a display medium that includes a covering member that covers a display area.

In the present invention, the following display medium is provided.
According to the first aspect of the present invention, at least one of the pair of flexible substrates, the display layer stacked between the pair of flexible substrates, and the flexible substrate is provided. A display medium having bending suppression means provided only in the non-display area of the conductive substrate and suppressing bending of the substrate.
According to a second aspect of the present invention, the bending suppressing means is a rod-shaped member attached to the one flexible substrate, or a depression, a convex, or a corrugated portion formed on the one flexible substrate. The display medium according to claim 1.
A third aspect of the present invention is the display medium according to the second aspect, wherein the bending restraining means is a recess formed in the one flexible substrate.
A fourth aspect of the present invention is the display medium according to any one of the first to third aspects, wherein the bending suppression means is provided so as to surround the display area.
A fifth aspect of the present invention is the display medium according to any one of the first to third aspects, wherein the bending suppression means is provided in an asymmetric shape at a position facing the display area across the display area.

According to the first aspect of the present invention, there is provided a display medium that secures rigidity without degrading display characteristics as compared with a display medium provided with a covering member that covers the display area.
According to the second aspect of the present invention, a display medium with higher rigidity is provided more reliably.
According to the third aspect of the present invention, when a bar-like member is provided on the substrate, or when a plurality of sheets are stacked and stored in comparison with the case where a substrate on which a convex portion is formed in advance is used, the depression portion of the display medium is used. A display medium is provided in which the projections and depressions corresponding to are overlapped with each other so as to coincide with each other.
According to the invention which concerns on Claim 4, compared with the case where a bending suppression means is not provided so that a display area may be enclosed, the display medium with higher rigidity is provided more reliably.
According to the invention which concerns on Claim 5, compared with the case where a bending suppression means is provided symmetrically on both sides of a display area, the display medium with which right and left specification is easy is provided.

It is the schematic which shows an example of a structure of the display medium which concerns on this embodiment. It is the schematic which shows the other example of arrangement | positioning of a bending suppression means. It is the schematic which shows the other example of arrangement | positioning of a bending suppression means. It is a schematic sectional drawing which shows the other example of the bending suppression means which concerns on this embodiment. It is a schematic sectional drawing which shows the other example of the bending suppression means which concerns on this embodiment. It is a schematic sectional drawing which shows the other example of the bending suppression means which concerns on this embodiment. It is a schematic sectional drawing which shows the other example of the bending suppression means which concerns on this embodiment. It is the schematic which shows the display medium which covered optical writing type electronic paper with the coating | coated member.

Optical writing type electronic paper is lightweight and flexible, and can be rewritten repeatedly. However, since it has flexibility, stress is easily applied. However, for example, as shown in FIG. 8, the larger the thickness of the covering member 8 for securing rigidity, the more easily the photoconductive layer 5 is separated from the light source and the resolution is reduced. The larger the value, the lower the reflectance passing through the covering member 9 and the image quality is lowered. In particular, when surface exposure using diffused light is used, the light is further diffused in the covering member 8 and the resolution is significantly reduced. On the other hand, if the thickness of the covering member is reduced in order to improve the resolution, the rigidity cannot be maintained, and it may be difficult to normally recognize an image or print by holding it by hand.
Further, when the thickness of the resin film 1 is increased in order to ensure rigidity, the same problem as when the thickness of the covering member 8 is increased occurs. When the thickness of the resin film 2 is increased, the same problem as when the thickness of the covering member 9 is increased occurs.
Further, when a new member is inserted in order to ensure rigidity, the applied voltage at the time of writing increases, and the writing device may be enlarged. In addition, the manufacturing process may increase and the manufacturing cost may increase.

The display medium according to the present embodiment includes at least one of a pair of flexible substrates, a display layer stacked between the pair of flexible substrates, and the pair of flexible substrates. Bending restraining means provided only in the non-display area of the flexible substrate and restraining the bending of the substrate.
Hereinafter, embodiments will be specifically described. In addition, about the member which has the substantially same function, the same code | symbol is used and description is abbreviate | omitted suitably.

(1) First Embodiment FIG. 1 schematically shows a display medium according to a first embodiment. The display medium 110 according to the present embodiment is optical writing type electronic paper, and a pair of flexible substrates 10 and 20 having optical transparency are arranged to face each other. Electrodes (not shown) are respectively provided on the display layer 50 side of the substrates 10 and 20. Between the two flexible substrates 10 and 20, a photoconductive layer 30 including an organic photoconductive material and a liquid crystal layer 40 including a liquid crystal display material are stacked as a display layer. A functional layer (not shown) such as a light blocking layer may be disposed between the photoconductive layer 30 and the liquid crystal layer 40.

Bar-shaped members 60A and 60B are attached to the display-side flexible substrate 20 along both edges in the longitudinal direction serving as non-display areas as bending restraining means for restraining the bending of the substrates 10 and 20. The display medium 110 having such a configuration has a certain degree of rigidity while ensuring flexibility, and also has a higher resolution for writing the photoconductive layer and liquid crystal as compared with a case where the thickness of the covering member is increased in order to ensure rigidity. The reflectance of the layer is improved, and the display characteristics are improved. Note that the improvement of display characteristics includes, for example, suppression of display unevenness, high resolution, and high reflectance.
Hereinafter, each component will be specifically described.

<Flexible substrate>
As the flexible substrates 10 and 20, a light transmissive resin film (film substrate) is used. Specifically, those composed of a polymer film such as polyethylene terephthalate, polysulfone, polyethersulfone, polycarbonate, polyethylene naphthalate are used.
Note that optical writing type electronic paper includes a so-called front writing method and a reverse writing method. In the front writing method, for example, the transparent substrate / liquid crystal layer / adhesive layer / photoconductive layer / light-shielding layer / substrate are laminated in this order from the display side, and the flexible substrate 10 on the non-display side does not necessarily transmit light. It is not necessary to have sex. On the other hand, in the reverse writing method, for example, the transparent substrate / liquid crystal layer / adhesive layer / light-shielding layer / photoconductive layer / transparent substrate are laminated in this order from the display side. May be a substrate having optical transparency.

  The thickness of the flexible substrates 10 and 20 is not particularly limited. However, if the substrate 10 on the optical writing side is too thick, the resolution may be lowered particularly when writing by surface exposure. If the substrate 20 on the display side is too thick. There is a possibility that the reflectance of the liquid crystal layer 40 is lowered. On the other hand, when a covering member such as a cover sheet is not used, the flexible substrates 10 and 20 themselves need a certain degree of strength in order to protect the display layer 50 from an external impact. Although it depends on the material of the flexible substrates 10 and 20, it is flexible from the viewpoints of suppressing image quality deterioration, strength for supporting and protecting the display layer 50, and flexibility and lightness of the display medium. The thicknesses of the substrates 10 and 20 are each in the range of 0.01 mm to 0.5 mm, for example.

As the electrodes provided on both the substrates 10 and 20, for example, ITO (Indium Tin Oxide) is used from the viewpoint of optical transparency. In addition to ITO, a light-transmitting electrical conductor such as a metal thin film such as Au, an oxide such as SnO ₂ or ZnO, or a thin film of a conductive polymer such as polypyrrole may be used. Each electrode is formed on the entire surface of the resin film, for example, by sputtering. Each electrode may be formed by printing, CVD, vapor deposition, or the like.
The thickness of each electrode is, for example, in the range of 10 nm to 200 nm.

  As an electrode form and a driving method, for example, both electrodes are common electrodes on each resin film, and driving methods described in Japanese Patent Application Laid-Open Nos. 2003-140184 and 2000-111942 are used. Alternatively, one of a pair of electrodes is a common electrode for each pixel of an image displayed on a display medium, and the other is an individual electrode for each pixel. Both electrodes are formed in strips in directions perpendicular to each other. Thus, a simple matrix driving method in which the positions facing each other are regions corresponding to one pixel, one electrode is a common electrode for each pixel, and the other is composed of band-shaped scanning electrodes and signal electrodes orthogonal to each other, An active matrix driving system or the like in which an active element such as a TFT is provided may be used.

  The flexible substrates 10 and 20 are preferably provided with a gas permeation prevention layer (gas barrier layer). The gas barrier layer has a role of suppressing moisture and oxygen permeation and improving the stability of the liquid crystal layer and the like. Moreover, you may provide various functional layers suitably, such as a light shielding layer, the anchor layer for improving adhesive force, and an insulating layer.

For example, a vacuum deposition method, a sputtering method, a physical vapor deposition method such as an ion plating method, or a chemical vapor deposition method such as CVD is appropriately used for forming a silicon oxide / aluminum oxide thin film as the gas barrier layer. For example, when employing the vacuum evaporation method, a mixture of SiO ₂ and Al, or a mixture of SiO ₂ and _Al 2 _{O 3} or the like is used as the deposition material. For heating, resistance heating, induction heating, electron beam heating or the like is employed. Alternatively, reactive vapor deposition using oxygen, nitrogen, hydrogen, argon, carbon dioxide gas, water vapor, or the like as a reactive gas, ozone addition, ion assist, or the like may be employed.
The thickness of the gas barrier layer is, for example, 1 nm or more and 500 nm or less.

<Display layer>
The display layer 50 may be selected according to the use and purpose of the display medium 110. For example, in the case of an optical writing type display medium, a display layer 50 having a configuration in which a photoconductive layer 30, a light shielding layer, and a liquid crystal layer 40 are stacked is provided between the electrodes of both the substrates 10 and 20.

-Photoconductive layer-
The photoconductive layer 30 includes: (a) a layer made of an amorphous semiconductor material such as amorphous silicon, ZnSe, or CdS as an inorganic semiconductor material; (b) a layer made of anthracene, polyvinylcarbazole, or the like as an organic semiconductor material; And a so-called organic photoconductor layer composed of a mixture or a laminate of a charge generation material that generates a charge by light irradiation and a charge transport material that generates a charge transfer by an electric field.

Examples of the charge generating material include perylene-based, phthalocyanine-based, bisazo-based, dithiopytochelopyrrole-based, squarylium-based, azurenium-based, and thiapyrylium / polycarbonate-based compounds. Examples of the charge transport material include trinitrofluorene-based, polyvinylcarbazole-based, oxadiazole-based, pyrarizone-based, hydrazone-based, stilbene-based, triphenylamine-based, triphenylmethane-based, diamine-based compounds, LiClO _{4, and the like.} A laminated body, a mixture, a microcapsule, or the like is used as an ion conductive material such as polyvinyl alcohol or polyethylene oxide to which is added, and as a composite of a charge generation material and a charge transport material.
The thickness of the photoconductive layer 30 is, for example, in the range of 1 μm or more and 100 μm or less, and it is desirable that the resistance ratio when the exposure light is irradiated and when the exposure light is not irradiated is large.

-Light shielding layer-
The light shielding layer is provided as necessary for the purpose of shielding the transmitted light from the non-display side, and at least a part of the wavelength of the exposure light transmitted through the organic photoconductor layer or the light such as the readout light from the external light source or the like A material having high electrical resistance is absorbed. The optical density required for the light shielding layer is not limited in general because it depends on the sensitivity of the photoconductive layer and the intensity of the readout light, but is preferably at least 1 and more preferably at least in the wavelength range to be shielded. The electrical resistance of the light shielding layer is preferably at least 10 ⁸ Ω · cm in terms of volume resistivity so as not to cause a reduction in resolution due to current in the light shielding layer. Furthermore, in order to increase the change in the partial pressure applied to the liquid crystal layer 40, the larger the capacitance of the light shielding layer, the better. Therefore, it is desirable that the dielectric constant is large and the thickness is thin.
The thickness of the light shielding layer is, for example, in the range of 0.5 μm to 3.0 μm.

The material of the light shielding layer is not particularly limited as long as it is a black material, and examples thereof include the following.
1) Organic pigments such as carbon black and aniline black, black pigments such as inorganic pigments such as CuO, MnO, Cr ₂ O ₃ , Fe—Cr pigments, Cu—Fe—Mn pigments, acrylic resins, epoxy resins, Black paint dispersed in resin binders such as polyester resin and polyurethane resin 2) Resin dyed with black dye 3) Vapor deposited film of black material such as carbon black When the light shielding layer is formed with water-based paint, the binder is water-soluble Resins, water / organic solvent-soluble resins, water-based emulsions, dispersions, and latexes are used.

-Liquid crystal layer-
For the liquid crystal layer 40, for example, a PDLC (Polymer Network Liquid Crystal) structure in which chiral nematic liquid crystal (cholesteric liquid crystal) is dispersed in a gelatin binder is employed. However, the present invention is not limited to this structure, and a cholesteric liquid crystal may be realized by a method in which a cholesteric liquid crystal is arranged in a cell having a fixed distance between electrodes through a partition wall or by a capsule liquid crystal. Further, the liquid crystal is not limited to the cholesteric liquid crystal, and a smectic A liquid crystal, a nematic liquid crystal, a discotic liquid crystal, or the like may be used.

As an auxiliary member that assists in changing the optical characteristics of the liquid crystal, it may be used in combination with a passive optical component such as a polarizing plate, a retardation plate, or a reflector, or a dichroic dye may be added to the liquid crystal.
The thickness of the liquid crystal layer 40 is, for example, in the range of 1 μm to 50 μm.

  Liquid crystal materials include known liquid crystal compositions such as cyanobiphenyl, phenylcyclohexyl, phenylbenzoate, cyclohexylbenzoate, azomethine, azobenzene, pyrimidine, dioxane, cyclohexylcyclohexane, stilbene, and tolan. Is done. Additives such as dyes such as dichroic dyes and fine particles may be added to the liquid crystal material, and those dispersed in a polymer matrix, polymer gels, and microcapsules may be used. The liquid crystal may be a polymer, medium molecule, or low molecule, or a mixture thereof.

  With the display layer 50 having the photoconductive layer 30 and the liquid crystal layer 40 as described above, the photoconductive layer 30 is irradiated with exposure light corresponding to image information, and at the same time, the electrodes of the flexible substrates 10 and 20 are applied. By applying a voltage, an image pattern is recorded on the liquid crystal layer 40 having a memory property. This image pattern is visualized by capturing external light and reflecting it.

<Bar-shaped member>
The rod-shaped members 60A and 60B that serve as bending restraining means are attached via adhesives, double-sided adhesive tape, and the like along both longitudinal edges of the flexible substrate 20 that serves as a non-display area. In the present embodiment, the “display area” is an area that overlaps the area where the display layer is present when viewed from the display surface of the flexible substrate, and means an area for displaying images, characters, etc. The display area is an area that does not overlap the area where the display layer is present when viewed from the display surface of the flexible substrate, or an image that overlaps the area where the display layer is present when viewed from the display surface of the flexible substrate. It means an area that does not need to be used for displaying characters. Although depending on the size of the flexible substrates 10 and 20, for example, a region within 30 mm inside from the outermost periphery along each edge of the substrate 20 may be set as a non-display region.

  The rod-shaped members 60A and 60B in the present embodiment have a semicircular or semi-elliptical cross section and are arranged along the longitudinal direction of the substrate 20, but if they have a hardness that suppresses bending of the substrate, The material, cross-sectional shape, length, width, and the like are not limited, and may be appropriately selected according to the material, size, shape, and the like of the substrate. For example, a rod-shaped member having a cross-sectional shape such as a circle or a polygon may be used. Moreover, the rod-shaped member may be provided in a state of being separated or divided into a plurality on each side of the substrate 20.

  Since the rod-shaped members 60A and 60B are not required to transmit light, the material constituting the rod-shaped member is not particularly limited as long as it has a hardness that suppresses bending of the substrate. From the viewpoint of suppressing bending, it is desirable to select a material having a higher hardness than the flexible substrate 20. For example, a general-purpose resin such as acrylic, polypropylene, or polyethylene, or a polymer material such as engineering plastic, a metal material such as iron or aluminum, wood, or ceramic may be used.

  The rod-shaped members 60A and 60B may be arranged in any part as long as they are non-display areas. For example, if the flexible substrates 10 and 20 are rectangular, the rod-shaped members 60A and 60B are arranged on one side in either the long side direction or the short side direction. By providing, it functions as a bending suppression means. For example, if the rod-shaped members 60A and 60B are provided at positions facing each other across the display area along both the long side direction or the short side direction of the substrate 20, the direction in which the rod-shaped members 60A and 60B are arranged is provided. Bending is more reliably suppressed.

  For example, as shown in FIG. 2, rod-shaped members 60 </ b> A, 60 </ b> B, 60 </ b> C, and 60 </ b> D may be provided along both edges in the long side direction and the short side direction so as to surround the display region 70. In this case, rigidity is provided in all directions, bending is more reliably suppressed, and display unevenness is also suppressed.

  Further, as shown in FIG. 3, the rod-shaped members 62 and 64 may be provided in an asymmetric shape at positions facing each other with the display region 70 interposed therebetween. If rod-like members 62 and 64 having asymmetric shapes are provided along both edges of the flexible substrate 20, for example, an individual identification (RFID) tag 72 by radio waves is placed on either the upper, lower, left or right side of the display medium. Even if it is provided at a position deviated from the above, the position of the tag 72 can be easily specified. For example, in the case where the display medium according to the present embodiment is inserted into a device that performs optical writing and writing is performed, if a mechanism capable of recognizing the difference between the rod-like members 62 and 64 is provided on the writing device side, the display medium is inserted. It is possible to prevent the individual identification (RFID) tag 72 from being recognized in the wrong direction. As a mechanism capable of recognizing the difference between the rod-like members 62 and 64, it may be a shape that can be securely fitted so that it cannot be inserted, or a means that can detect the shape of an optical sensor or the like is provided in the optical writing device so that the wrong direction is obtained. An error may be displayed when it is inserted.

  Further, the rod-shaped members 62 and 64 are not limited to being provided on the display-side substrate 20, and may be provided on the optical writing-side substrate 10 or on both the substrates 10 and 20. The optical writing device may be designed so as not to interfere with the rod-shaped member, but in the case of a simple configuration, the writing method (front writing method or reverse writing method) is used so that the rod-shaped members 60A and 60B do not get in the way. Depending on the situation, it is desirable to provide it on one substrate side. For example, in the reverse writing method, as shown in FIG. 1, the rod-shaped members 60A and 60B are provided only in the non-display area of the display-side substrate 20, so that the rod-shaped members 60A and 60B can be used when writing from the substrate 10 on the optical writing side. It is prevented from getting in the way, and the resolution is more reliably improved.

  The bending suppressing means is not limited to the rod-shaped members 60A and 60B, and other forms may be adopted. In each embodiment described below, a flexible substrate, an electrode, a liquid crystal layer, a photoconductive layer, a light shielding layer, and the like are the same as those in the first embodiment, and thus description thereof will be omitted as appropriate. Further, the position where the bending prevention means is provided is also applied in the same manner as the case where the rod-shaped members 60A and 60B are provided, and thus description thereof will be omitted as appropriate.

(2) Second Embodiment FIG. 4 schematically shows a cross section in the thickness direction of a display medium according to a second embodiment. The display medium 120 is provided with convex portions 22A and 22B along both longitudinal edges of the flexible substrate 20 on the display side. If the flexible board | substrate 20 with which such convex parts 22A and 22B are formed previously is used, convex parts 22A and 22B will function as a bending suppression means. The shape of the protrusions 22A and 22B is not limited to a semicircular cross-sectional shape as shown in FIG. 4, and may have another cross-sectional shape such as a circle or a polygon.

Further, the side on which the convex portions 22A and 22B serving as bending restraining means are provided is not particularly limited, and the convex portions 22A and 22B may be formed on the substrate 10 on the writing side or both the substrates 10 and 20. The optical writing device may be designed so as not to interfere with the convex portions 22A and 22B. However, in the case of a simple configuration, the convex portions 22A and 22B become an obstacle at the time of optical writing from the substrate side on the writing side. In order to prevent this, as shown in FIG. 4, the substrate 10 on the optical writing side is a flat flexible substrate having no projections, and the substrate 10 on the display side has projections 22A, 22A, It is desirable to use a flexible substrate having 22B.
When the display medium 120 according to the present embodiment is manufactured, the flexible substrate 20 in which the convex portions 22A and 22B are formed in advance on one side is used, and the first and second flexible substrates 10 and 20 are disposed between the flexible substrates 10 and 20. What is necessary is just to manufacture so that it may become the structure by which 1 electrode, the photoconductive layer 30, the light shielding layer, the liquid crystal layer 40, and the 2nd electrode were laminated | stacked one by one.

(3) Third Embodiment FIG. 5 schematically shows a cross section in the thickness direction of a display medium according to a third embodiment. In the display medium 130, recesses 12 </ b> A and 12 </ b> B are provided along both longitudinal edges of the flexible substrate 10. In this case, since the depressions 12A and 12B function as bending restraining means, a certain degree of rigidity is imparted and image quality deterioration is suppressed without providing a covering member.
In the case of manufacturing the display medium 130 according to the present embodiment, for example, the display layer (the photoconductive layer 30 and the liquid crystal layer 40) is provided along at least both the longitudinal or lateral edges of the flexible substrates 10 and 20. The non-display area is not provided, and if necessary, the two substrates 10 and 20 are bonded to each other along both edges of the non-display area via an adhesive or the like, and the recessed portions 12A and 12B are formed along both edges. Press work as shown. The adhesive may not be provided between the substrates 10 and 20, and the substrates 10 and 20 may be welded together with the pressing.

  If the recesses 12A and 12B are provided on the flexible substrate 10 itself, a plurality of portions are provided as compared with the case where the rod-shaped members 60A and 60B are provided on the substrate or the case where the substrate on which the protrusions 22A and 22B are previously formed is used. When stacking and storing, the thickness can be reduced and the storage space can be reduced. For example, if stacking is performed so as to be the convex portion of the recessed portion on the upper side of the medium, the lower side of the medium overlapping therewith becomes the concave portion of the recessed portion, so that they are stacked without a gap.

(4) Fourth Embodiment FIG. 6 schematically shows a cross section in the thickness direction of a display medium according to a fourth embodiment. In this display medium 140, display layers (the photoconductive layer 30 and the liquid crystal layer 40) are provided on the entire surfaces of the flexible substrates 10 and 20, and the flexible substrates 10 and 20 together with the display layers 30 and 40 are both in the longitudinal direction. Indentations 12A and 12B are formed along the edges. Also in the display medium 140 according to the present embodiment, the depressions 12A and 12B function as bending restraining means, and a certain degree of rigidity is imparted and image quality deterioration is suppressed without providing a covering member.

  After arranging the display layers 30 and 40 so as to be sandwiched between the entire surfaces of the substrates 10 and 20, the depressions 12A and 12B may be formed together with the display layers 30 and 40 by pressing. Note that the side on which the recesses 12A and 12B are provided is not particularly limited, but a convex portion is formed on the opposite substrate in accordance with the recesses 12A and 12B provided on one substrate side. Although it may be designed so as not to interfere with the depression 12 on the apparatus side, in the case of a simple configuration, the depressions 12A, 12A and 12A are formed on the substrate 10 on the optical writing side so that the convex portion does not interfere with optical writing. It is desirable to provide 12B.

(5) Fifth Embodiment FIG. 7 schematically shows a cross section in the thickness direction of a display medium according to a fifth embodiment. The display medium 150 is provided with corrugated portions 14A and 14B along both edges of the flexible substrates 10 and 20. The corrugated portions 14A and 14B provided in the non-display areas of the flexible substrates 10 and 20 also function as bending suppressing means, and a certain degree of rigidity is given without providing a covering member, and a decrease in display characteristics is suppressed. Will be.
When manufacturing the display medium 150 according to the present embodiment, an adhesive is applied between the flexible substrates 10 and 20 as necessary, and the corrugated portions are pressed by pressing along both edges that become non-display areas. 14A and 14B may be formed.

In the above description, the optical writable display medium (electronic paper) has been mainly described. However, the present invention is not limited to this. For example, an organic electroluminescent element or a micro-device is provided between the flexible substrates opposed to each other. You may apply to the display medium which provides a display layer, such as a capsule, and displays.
Further, for example, the electrodes may be processed into a stripe shape to form a simple matrix display element. Alternatively, an active element such as a thin film transistor or a thin film diode may be provided on a substrate on the surface opposite to the display to form an active matrix drive type display medium.
Further, the bending suppressing means is not limited to the illustrated one, and other forms may be adopted.

10, 20 Flexible substrate 12A, 12B Depression 14A, 14B Waveform 22A, 22B Convex 30 Photoconductive layer 40 Liquid crystal layer 50 Display layer 60A, 60B, 60C, 60D Bar-shaped member 62, 64 Bar-shaped member 70 Display area 110 , 120, 130, 140, 150 Display media

Claims (5)

A pair of opposing flexible substrates;
A display layer laminated between the pair of flexible substrates;
A display medium, comprising: a bending suppression means that is provided only in a non-display area of at least one of the pair of flexible substrates and suppresses bending of the substrate.   2. The display according to claim 1, wherein the bending suppression means is a rod-like member attached to the one flexible substrate, or a depression, a convex, or a corrugated portion formed on the one flexible substrate. Medium.   The display medium according to claim 2, wherein the bending prevention means is a depression formed in the one flexible substrate.   The display medium according to any one of claims 1 to 3, wherein the bending suppression means is provided so as to surround a display area.   The display medium according to any one of claims 1 to 3, wherein the bending suppression means is provided in an asymmetric shape at positions facing each other across the display area.

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