JP2009294488A - Display recording medium and image writing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve problems wherein, in a display recording medium of a conventional configuration, the photoconductive layer of the medium degrades by light because the layer is always exposed to external light (indoor light and outdoor light) and that, because the photoconductive layer is disposed in the opposite side to an observation side while a solid electrode is disposed in the observation side, writing in the observation side is impossible. <P>SOLUTION: A display recording medium 1 is disclosed, comprising at least a substrate 2, a light absorbing member 3 absorbing light, a conductive layer 4 and a memory-type display layer 5, layered in this order, in which an optical switching element 9 for optical writing is provided in the side close to an image writing device 8. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a display recording medium for displaying an image including character information and graphics, and an image writing apparatus for writing an image on the display recording medium.

  Realization of a rewritable display storage medium that replaces paper is desired, and it is bright, easy to read with high contrast, lightweight and flexible, has other memory characteristics, and can display and store information without a power source. Several techniques have been proposed for possible reflective full-color display storage media.

  Among them, a display storage medium capable of color display has been proposed in which cholesteric liquid crystal layers that selectively reflect different colors are stacked in the observation direction.

  A cholesteric liquid crystal having positive dielectric anisotropy has a planar phase in which the helical axis is perpendicular to the cell surface and causes selective reflection with respect to incident light, and the helical axis is almost parallel to the cell surface. Three states are shown: a focal conic phase that is transmitted while being slightly scattered forward, and a homeotropic phase in which the helical structure is unwound and the liquid crystal director is directed in the direction of the electric field and transmits incident light almost completely.

  Among the above three phases, the planar phase and the focal conic phase can exist bistable without an electric field. Therefore, the phase state of the cholesteric liquid crystal is not uniquely determined with respect to the electric field strength applied to the liquid crystal layer. When the planar phase is in the initial state, the planar phase and the focal conic phase are increased as the electric field strength increases. When the focal conic phase is in the initial state, the focal conic phase and the homeotropic phase change in this order as the electric field strength increases.

  On the other hand, when the electric field intensity applied to the liquid crystal layer is suddenly reduced to zero, the planar phase and the focal conic phase are maintained as they are, and the homeotropic phase is changed to the planar phase.

  Accordingly, the cholesteric liquid crystal layer immediately after the voltage is applied exhibits a switching behavior, and when the electric field strength due to the applied voltage is equal to or higher than the threshold, the phase changes from the homeotropic phase to the planar phase, and the selective reflection state is reached. Sometimes, it is in a transmission state by the focal conic phase, and when it is below the threshold, it is in a state in which the state before voltage application is continued, that is, a selective reflection state by the planar phase or a transmission state by the focal conic phase.

  (Patent Document 1) discloses a display storage medium capable of full color display, having a memory property with no power supply using the cholesteric liquid crystal, and capable of rewriting an image in a short time by an external device, an image writing method thereof, and An image writing device is disclosed.

  FIG. 5 is a diagram showing a schematic configuration of a conventional display recording medium and image image writing apparatus. In FIG. 5, 101 is a display storage medium, 102 and 103 are transparent base materials, 104 is a light absorbing member, 105 is a transparent conductor layer provided on the display side, 106 is a memory display layer, 106A, 106B and 106C are memory characteristics. Three liquid crystal layers composed of cholesteric liquid crystals that selectively reflect different colored lights in the visible light that constitute the display layer 106, 107 is a separator provided between the liquid crystal layers 106A, 106B, and 106C, 108 is an optical switch element, 109 is a photoconductive layer that constitutes the optical switch element 108 whose impedance changes according to the amount of light applied, 110 is a transparent conductor layer that also constitutes the optical switch element 109, 111 is an image writing device, and 112 is a display storage medium 101 is a light irradiating unit that irradiates writing light on the opposite side of the display surface, and 113 is displayed based on image data. A driving pulse circuit unit for applying a voltage between the transparent conductive layer 103 of the storage medium 101 and the transparent conductive layer 109 of the optical switch element 108, and 114 is a control circuit unit for controlling the driving pulse circuit unit 113 and the light irradiation unit 112. .

In the conventional display recording medium 101, the display layer 106 and the optical switch element 108 are integrally formed. When image information is input from the opposite side to the display side of the display recording medium 101, the drive pulse voltage is supplied to the transparent electrode 103 and the optical switch element 108 of the display recording medium 101 by the drive pulse circuit unit 113 provided in the image writing device 8. It is applied between the transparent conductive layers 110 provided, and at the same time, according to the image information, the light irradiation unit 112 of the image writing device 8 performs light irradiation to write an image.
JP 2000-111942 A

  However, in the display recording medium having the above-described conventional configuration, the photoconductive layer is always exposed to external light (because it is exposed to indoor light and outdoor light, and thus the photoconductive layer is subject to light degradation. The display recording medium has a problem that writing cannot be performed from the observation side because the photoconductive layer is provided on the side opposite to the observation side and the solid electrode is provided on the observation side.

  The present invention solves such a conventional problem, and a display recording medium and an image writing method which can be used for a long period of time without deterioration of writing characteristics even when the display recording medium is exposed to external light. The purpose is to provide. It is another object of the present invention to provide a display recording medium and an image writing apparatus that can perform additional recording on the display recording medium from the observation side.

  In order to achieve the above object, the first invention of the present application is formed by laminating at least a base material, a light absorbing member that absorbs light, a conductor layer, and a memory display layer in this order.

  A second invention of the present application is a display medium in which the memory-type display layer is formed by laminating one or a plurality of cholesteric liquid crystals that selectively reflect different colors of light.

  According to a third aspect of the present invention, the memory display layer is formed by laminating a layer obtained by applying and drying a plurality of microencapsulated cholesteric liquid crystals that selectively reflect one or different colors of light together with a binder. It is a display medium composed of a memory-type display layer, and a stable image can be displayed without being disturbed even if the display medium is pressed or bent.

  According to the display recording medium and the image writing apparatus of the present invention, even if the display recording medium is exposed to external light, it is not deteriorated in light, and can be stably written over a long period of time. Can be added.

  Embodiments of the present invention will be described below.

(Embodiment 1)
1 is a diagram showing a schematic configuration of a display recording medium according to an embodiment of the present invention, FIG. 2 is a diagram showing a schematic configuration of an image image writing device according to an embodiment of the present invention, and FIG. 3 is another embodiment of the present invention. It is a figure which shows schematic structure of the display recording medium in the form.

  In FIG. 1, 1 is a display storage medium, 2 is a base material, 3 is a light absorbing member, 4 is a conductor layer, 5 is a memory display layer, and 5A, 5B, and 5C are visible in the memory display layer 5, respectively. Three liquid crystal layers 6 made of cholesteric liquid crystals that selectively reflect different color lights in the light, 6 are separating plates provided between the liquid crystal layers 5A, 5B, and 5C, respectively. Further, 7 is an irregular reflection preventing layer that also serves as protection provided as necessary.

  As the base material 2, glass, silicon, or a polymer film such as polyester (polyethylene terephthalate), polysulfone, polyethersulfone, or polycarbonate can be used, and the base material 2 is formed of an insulating material.

  The light absorbing member 3 is not particularly limited as long as it absorbs incident light transmitted through the liquid crystal layers 5A, 5B, and 5C, and has an insulating property such as an inorganic substance or a polymer containing a black dye. It is preferable that the dielectric constant be as large as possible in order to increase the partial pressure ratio to the liquid crystal layers 5A, 5B, and 5C. The light absorbing member 3 can also be configured to serve as the base material 2 as shown in FIG.

The conductor layer 4 is formed on the substrate 2 by a vapor deposition method, a sputtering method, or the like using a conductive material such as ITO or SnO ₂ . Moreover, you may form well-known functional films, such as a liquid crystal aligning film, on the surface as needed.

  The cholesteric liquid crystal constituting the liquid crystal layers 5A, 5B and 5C is a chiral nematic liquid crystal in which an optically active group is introduced into a part of a steroidal cholesterol derivative or a nematic liquid crystal such as a Schiff base type, an azo type, an ester type or a biphenyl type, Or these are Schiff base, azo, azoxy, ethane, biphenyl, terphenyl, cyclohexylcarboxylic acid ester, phenylcyclohexane, benzoic acid ester, pyrimidine, dioxane, tolan, cyclohexyl. A material added as a chiral agent to a nematic liquid crystal having positive dielectric anisotropy such as cyclohexane ester or alkenyl, or a mixed liquid crystal thereof can be used.

  The helical pitch of the cholesteric liquid crystal is adjusted by the amount of chiral agent added to the nematic liquid crystal. For example, the center wavelengths of selectively reflected light of the liquid crystal portions 5A, 5B, and 5C are 400 to 500 nm, 500 to 600 nm, and 600 to 700 nm, respectively. Selected to be within range.

  In addition, the liquid crystal layers 5A, 5B, and 5C are composed of only cholesteric liquid crystal, and have a PNLC structure in which a continuous polymer of cholesteric liquid crystal includes a network polymer, and cholesteric liquid crystal is dispersed in a droplet shape in the polymer skeleton. A PDLC structure can also be used. By adopting a PNLC structure or a PDLC structure, an anchoring effect is generated at the interface between the cholesteric liquid crystal and the polymer, the planar state or the focal conic state can be stabilized without voltage, and the switching speed can be further increased. Can be improved. In addition, the viewing angle is improved by the fluctuation of the helical axis.

  The separation plate 6 can be made of the same polymer film as that of the substrate 2 and is formed of a light transmissive material. The thickness is several μm to several tens μm, and in order to increase the partial pressure ratio to the liquid crystal layers 5A, 5B, 5C, it is preferable that the dielectric constant is as large as possible. Moreover, you may form well-known functional films, such as a liquid crystal aligning film, on the surface as needed.

  Further, in FIG. 2, 8 is an image writing device, 9 is an optical switch element that is brought into close contact with the display recording medium 1, 10 constitutes an optical switch element 9 whose impedance changes according to the amount of light applied, and a photoconductive layer. 11 is a transparent conductor layer that also constitutes the optical switch element 9, 12 is a pressing roller that brings the display recording medium 1 into close contact with the optical switch element 9, and 13 is a laser scan that irradiates the display surface side of the display storage medium 1 with writing light. The unit, 14 is a drive pulse circuit unit, and 15 is a drive pulse circuit 14 in which the voltage application unit 13 applies a voltage between the conductive layer 4 of the display storage medium 1 and the conductive layer 11 of the optical switch element 9 based on the image data. A control circuit unit for controlling the bias voltage and the write light irradiated to the photoconductive layer 10 by the laser scan unit 13, and 16a a drive pulse circuit unit and an optical switch. Contact connecting elements 9, 16b is a contact for connecting the conductive layer 4 of the display recording medium 1 and the driving pulse circuit portion 14.

  The photoconductive layer 10 is formed by depositing a charge generating material by a vapor deposition method, a sputtering method, an ion plating method, a CVD method, or the like, or by dispersing the charge generating material in a resin binder, and by spin coating method, dipping method, or the like. Those coated, or those obtained by stacking a charge transport layer on these charge generation layers can be used.

  As the charge generation material, inorganic materials such as a-Si, organic materials such as phthalocyanine and azo, and organic materials such as carbazole, triazole, amine, and nitrofluorenone can be used as the charge transport material. .

  In the image writing according to the present invention, the image writing device 8 and the display storage medium 1 are separately formed. In writing an image, the optical switch element 9 of the image writing device 8 and the display side of the display storage medium 1 are brought into close contact with the pressing roller 12. At this time, the optical switch element 9 and the display storage medium 1 are in line contact because they are pressed by the pressing roller 12.

  When the drive pulse voltage is applied by the drive pulse circuit unit 15, the transparent conductor layer 11 of the optical switch element 9 of the image writing device 8 and the conductor layer of the display storage medium 1 are contacted by the contact 16a and the contact 16b. A drive voltage is applied between the four.

  However, in this state, since the optical switch element 9 is not irradiated with the write light, the optical switch layer remains at a high resistance, and no electric field is applied to the memory display layer 5.

  In order to write an image, according to the pixel data, the optical scanning element 9 provided in the image writing device 8 is selectively switched by the laser scanning unit 13 to write light, and the display recording medium 1 is transported (not shown). The scanning is performed while transporting line by line.

  Between the conductor layer 4 of the display storage medium 1 and the transparent conductor layer 11 of the image writing device 8, a scanning method for forming an image for each color and the voltage on the same line are changed by selecting a driving pulse voltage. A line sequential scanning method that repeatedly scans and obtains RGB data, and the entire surface of the display recording medium 1 is scanned with the same drive pulse voltage, then the voltage is changed and rescanned. A frame sequential method for obtaining data is possible.

  However, the laser scan unit 13 is not limited to this, and any laser light unit may be used as long as it can irradiate the display storage medium 1 with an arbitrary amount of writing light, such as an LED array, a CRT display, a plasma display, and an EL display. Light emitting elements, light control elements such as liquid crystal shutters, and the like can be employed.

  As described above, when a drive pulse voltage is applied to the display storage medium 1 from the external image writing device 8 and an arbitrary amount of writing light is irradiated, the arbitrary drive pulse voltage is applied to the entire memory display layer 5. The voltage is applied to each of the liquid crystal layers 5A, 5B, and 5C by electrostatic capacitance division. Depending on the voltage, the alignment state of the cholesteric liquid crystals in each of the liquid crystal layers 5A, 5B, 5C changes.

  Therefore, in the display storage medium 1 of the present invention, the distribution ratio of the drive pulse voltage applied to the memory display layer 5 to the liquid crystal layers 5A, 5B, 5C and the liquid crystal layers with respect to the actually applied voltage. By controlling two of the electro-optic responses of 5A, 5B, and 5C, the electro-optic responses of the liquid crystal layers 5A, 5B, and 5C with respect to the drive pulse voltage applied to the entire memory display layer 5 are set to a desired configuration. Can be.

  Specifically, the threshold voltages of the liquid crystal layers 5A, 5B, and 5C that change from the planar phase to the focal conic phase and the threshold voltages that change from the focal conic phase to the planar phase are in the order of the liquid crystal layers 5A, 5B, and 5C. After sequentially setting the liquid crystal layers 5A, 5B, and 5C to the planar phase or the focal conic phase by the reset voltage, the planar phase is further changed to the focal conic phase, or the focal conic phase is changed to the planar phase by the select voltage. To change.

  That is, the drive pulse voltage is composed of an AC pulse reset period and a select period, and then a non-voltage display period, and a drive pulse voltage having a relationship of voltage of the reset period> voltage of the select period is applied, and at least the reset period and The laser scanning unit 13 irradiates writing light so as to include the selection period.

  As a result, the drive pulse voltage to be applied is selected so as to create the following state.

  The liquid crystal layer 5A has a planar structure, and the liquid crystal layers 5B and 5C have a focal conic structure.

  The liquid crystal layer 5B has a planar structure, and the liquid crystal layers 5A and 5C have a focal conic structure.

  The liquid crystal layer 5C has a planar structure, and the liquid crystal layers 5A and 5B have a focal conic structure.

  The liquid crystal layers 5A and 5B have a planar structure, and the liquid crystal layer 5C has a focal conic structure.

  The liquid crystal layers 5B and 5C have a planar structure, and the liquid crystal layer 5A has a focal conic structure.

  For example, if the liquid crystal layers 5A, 5B, and 5C selectively reflect colors R, G, and B, respectively, white (W) when all three layers of the liquid crystal layers 5A, 5B, and 5C are in a planar structure. become. On the other hand, if all three of the liquid crystal layers 5A, 5B, and 5C are in a focal conic state, black (B) is obtained.

  When the liquid crystal layer 5A has a planar structure and the liquid crystal layers 5B and 5C are in a focal conic state, R reflected light is obtained, the liquid crystal layer 5B has a planar structure, and the liquid crystal layers 5A and 5C have a focal conic state. If there is, G reflected light is obtained. When the liquid crystal layer 5C has a planar structure and the liquid crystal layers 5A and 5B have a focal conic structure, G reflected light is obtained.

  Furthermore, a multi-valued color image can be displayed by performing area gradation such as dithering or error diffusion.

  Further, in the above description, the image writing device 8 is used to write an image on the display recording medium 1. However, the conductor layer 4 of the display recording medium 1 and the surface of the display recording medium 1 are point-contacted and driven. An image can be written without irradiating light through the optical switch element 10 provided in the image writing device 8 as long as it can apply a pulse voltage.

(Embodiment 2)
FIG. 4 is a diagram showing a schematic configuration of a pen-type image image writing apparatus according to another embodiment of the present invention. In FIG. 4, 17 is a pen-type image writing device, 18 is a drive pulse circuit unit, 19 is a contact, and 20 is a switch for connecting the drive pulse circuit 18 and the contact 19.

  In order to write an image on the display recording medium with the pen-type image writing device 17 configured as described above, the contact 19 is brought into contact with the display side of the display recording medium 1 and the switch 20 is operated. An image can be written as line information by applying a drive pulse voltage to the contact 19 and simultaneously moving the pen-type image writing device 17 on the surface of the display recording medium 1.

  When the image writing is stopped, the connection between the drive pulse circuit 18 and the contact 19 is canceled by the switch 20.

  The difference between the first embodiment and the second embodiment is that the writing device does not have an optical switch element and a laser scan unit. In the pen-type image writing device 17, since the writing position is selected by the contact 19, the laser scanning unit provided in the first embodiment and the optical switch element for controlling voltage application are unnecessary.

  As described above, according to the present invention, an image writing apparatus provided with a display storage medium capable of rewriting an image by an external device and having a memory property and capable of full color display, and an optical switch element composed of the photoconductive layer. Thus, the photoconductive layer can be installed in a dark place in the apparatus, and photodegradation due to exposure to external light from the photoconductive layer can be prevented. Further, there is no conductive layer on the display side of the display recording medium, and partial rewriting can be performed from the display side.

  The display storage medium and the image writing apparatus according to the present invention may be any display recording medium in which at least a base material, a light absorbing member that absorbs light, a conductor layer, and a memory display layer are laminated in this order. , A display recording medium provided with a display layer color filter using an electronic powder fluid composed of two kinds of particles having different light reflection characteristics and charging characteristics enclosed in a micro cell, or different light reflection characteristics and charging characteristics It is also suitable for a display recording medium in which a color filter composed of a plurality of colors is laminated on a capsule layer in which capsules containing two types of particles as a suspension containing a dispersion medium are applied together with a binder.

The figure which shows schematic structure of the display recording medium in embodiment of this invention The figure which shows schematic structure of the image image writing apparatus in embodiment of this invention. The figure which shows schematic structure of the display recording medium in other embodiment of this invention. The figure which shows schematic structure of the pen-type image image writing apparatus in other embodiment of this invention. The figure which shows schematic structure of the conventional display recording medium and an image image writing apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Display recording medium 2 Base material 3 Light absorption member 4 Conductor layer 5 Memory display layer 5A Liquid crystal layer 5B Liquid crystal layer 5C Liquid crystal layer 6 Separation plate 7 Diffuse reflection prevention layer 8 Image writing device 9 Optical switch element 10 Photoconductive layer 11 Transparent Conductor layer 12 Press roller 13 Laser scan unit 14 Drive pulse circuit unit 15 Control circuit unit 16a Connector 16b Connector 17 Pen-type image writing device 18 Drive pulse circuit unit 19 Contact 20 Switch

Claims (12)

A display recording medium in which at least a substrate, a light absorbing member that absorbs light, a conductor layer, and a memory display layer are laminated in this order. The display memory according to claim 1, wherein the memory-type display layer includes a memory-type display layer configured by laminating a plurality of cholesteric liquid crystals that selectively reflect one or different colors of light. Medium. The memory display layer is composed of a memory display layer formed by laminating one or a plurality of microencapsulated cholesteric liquid crystals that selectively reflect different colors of light together with a binder. The display storage medium according to claim 1. 2. The display recording medium according to claim 1, wherein the memory-type display layer is configured by enclosing two kinds of particles having different light reflection characteristics and charging characteristics in a minute cell. 2. The memory cell according to claim 1, wherein the memory display layer is provided with a micro cell in which two kinds of particles having different light reflection characteristics and charging characteristics are encapsulated, and a color filter having a plurality of colors in the cell. Display recording media. The display according to claim 1, wherein the memory display layer is coated with a binder containing a suspension in which two kinds of particles having different light reflection characteristics and charging characteristics are dispersed in a dispersion medium. recoding media. The memory display layer is composed of a capsule layer in which two kinds of particles having different light reflection characteristics and charging characteristics are encapsulated as a suspension containing a dispersion medium and coated with a binder, and the capsule layer has a plurality of colors. The display recording medium according to claim 1, wherein color filters are laminated. The display storage medium according to claim 1, wherein the base material is formed of a member that absorbs light, and also serves as a light absorption layer that absorbs light. An optical switch element comprising a photoconductive layer in contact with the display recording medium according to claim 1 provided with a transparent conductive layer on a side opposite to the photoconductive layer in contact with the display recording medium, and A contact means for contacting the photoconductive layer of the optical switch element on the opposite side of the substrate of the display recording medium, and a voltage applied to the conductive layer of the display recording medium and the transparent conductive layer of the optical switch element An image writing apparatus including at least a voltage applying unit that irradiates the optical switch element with a light spot according to image information displayed on the display recording medium. The memory display layer of the display recording medium is composed of cholesteric liquid crystal, and the voltage applied by the voltage applying means to the memory display layer is bounded by the threshold voltage of the cholesteric liquid crystal of the memory display layer. The image writing apparatus according to claim 9, wherein a voltage of a plurality of stages is generated. The image writing apparatus according to claim 9, wherein the contact means is configured so that the display recording medium and the optical switch element are in line contact. A contact that contacts the display side of the display recording medium according to claim 1, a voltage applying unit that applies a voltage to the contact, and a switch that selects connection between the contact and the voltage applying unit Including pen-type image writing device.

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