JP4591036B2 - Image display medium, electrophoretic display device, and method of manufacturing image display medium - Google Patents

Description

  The present invention relates to an image display medium, an electrophoretic display device, and an image display medium manufacturing method, and in particular, an image display medium capable of multicolor display with high brightness, an electrophoretic display device including the image display medium, and The present invention also relates to a method for manufacturing the image display medium.

Conventionally, as an image display medium that can be repeatedly rewritten, an electrophoretic image display medium capable of multicolor display has been proposed. For example, Japanese Patent Laid-Open No. 2003-108035 (Patent Document 1) discloses a scattering reflection type color display capable of multicolor display by previously forming a color filter at a position corresponding to an electrode on a display medium of a first substrate. The body is listed. In Japanese Patent Laid-Open No. 2000-35769 (Patent Document 2), microcapsules of three different colors are injected into each of three types of nozzles for each color, and the first electrode is divided from the nozzles one by one by an inkjet method. A display panel manufactured by stamping on an electrode is described.
JP 2003-108035 A JP 2000-35769 A

  However, in the case of a reflection-type image display medium such as an electrophoretic method, if a color filter layer is separately provided as described in Patent Document 1, the brightness of the screen becomes low (the screen becomes dark). There was a problem that the quality of the color deteriorated. Further, the method described in Patent Document 2 has a problem that it is difficult to control the timing of launching the microcapsules and it is difficult to align the microcapsules.

  The present invention has been made to solve the above-described problems, and can be manufactured by a simple method, and can display an image display medium having high brightness and multicolor display, and electrophoresis including the image display medium It is an object of the present invention to provide a display device and a method for manufacturing the image display medium.

  In order to achieve this object, an image display medium according to claim 1 includes a pair of substrates disposed substantially in parallel and spaced apart, charged particles, and the charged particles, An electrophoretic medium disposed between a pair of substrates, and the charged particles contained in the electrophoretic medium are moved by an electric field generated between the pair of substrates to switch a display state. The electrophoretic medium comprises a first medium exhibiting a first color and a second medium capable of phase separation with respect to the first medium at least at room temperature and exhibiting a second color. The second medium and the first medium form a predetermined pattern in a state of being phase-separated from each other.

  The image display medium according to claim 2 is the image display medium according to claim 1, wherein the first surface treatment unit has more affinity for the first medium than the second medium, and the first medium is more than the first medium. A second surface treatment unit having a higher affinity for the second medium, and each of the second surface treatment unit and the first surface treatment unit includes the electrophoresis on at least one of the pair of substrates. A surface in contact with the medium is arranged corresponding to the predetermined pattern.

  In addition, in claim 2, “the second surface treatment unit and the first surface treatment unit each correspond to the predetermined pattern on a surface of the at least one substrate of the pair of substrates that contacts the electrophoretic medium. "Is arranged" means that both the first surface treatment unit and the second surface treatment unit may be arranged in a predetermined pattern only on one of the pair of substrates. And the second surface treatment unit may be arranged in a predetermined pattern on both substrates, or the first surface treatment unit and the second surface treatment unit are arranged on different substrates. This means that the pattern may be formed.

  The image display medium according to claim 3 is the image display medium according to claim 1 or 2, wherein each of the first medium and the second medium is insoluble in the other or insoluble in the other. Any of the solutions containing a solvent.

  In claim 3, "the first medium and the second medium are either a solvent insoluble in the other or a solution containing a solvent insoluble in the other" means the first The combination of the medium 30a and the second medium 30b is a combination of solvents that are insoluble with each other, a combination of solutions that include a solvent that is insoluble with each other, or a combination of solvents that are insoluble with each other. It means a combination with a solution containing a solvent.

  The image display medium according to claim 4 is the image display medium according to claim 3, wherein one of the first medium and the second medium is water or an aqueous solution, and the other is a solvent insoluble in water or a solvent thereof. It is a solution containing.

  The image display medium according to claim 5 is the image display medium according to claim 4, wherein the water is distilled water or deionized water.

  The image display medium according to claim 6 is the image display medium according to claim 4 or 5, wherein the solvent insoluble in water is an aromatic hydrocarbon solvent, an aliphatic hydrocarbon solvent, a halogenated hydrocarbon solvent, or silicone oil. Or a high-purity petroleum alone or a mixture containing two or more of these.

  The image display medium according to claim 7 is the image display medium according to any one of claims 1 to 6, wherein the charged particles have a higher affinity for the first medium than for the second medium. 1st particle | grains which have a surface, and 2nd particle | grains which have the surface which shows more affinity with respect to the said 2nd medium than the said 1st medium.

  An image display medium according to an eighth aspect is the image display medium according to the seventh aspect, wherein the first particles and the second particles are colored in different colors.

  The image display medium according to claim 9 is the image display medium according to any one of claims 1 to 8, wherein the first medium and the second medium are colored in mutually different colors.

  An image display medium according to a tenth aspect is the image display medium according to any one of the first to ninth aspects, wherein a pair of electrodes are respectively provided on surfaces of the pair of substrates facing each other, and the pair of electrodes is provided. A liquid-resistant protective film is provided on the surface of each electrode in the electrode.

  An image display medium according to an eleventh aspect is the image display medium according to the tenth aspect, wherein the protective film is a protective film containing a fluorine-containing compound.

  An image display medium according to a twelfth aspect is the image display medium according to any one of the first to eleventh aspects, wherein each of the pair of substrates has flexibility.

  An image display medium according to a thirteenth aspect is the image display medium according to any one of the first to twelfth aspects, further comprising a spacer for maintaining a distance between the pair of substrates at a predetermined distance or more.

  An image display medium according to a fourteenth aspect is the image display medium according to any one of the first to thirteenth aspects, wherein one of the pair of electrodes is a first electrode and a second electrode that are alternately arranged while being separated from each other. The first medium is disposed at a position corresponding to the position of the first electrode, while the second medium is disposed at a position corresponding to the position of the second electrode. The predetermined pattern is formed.

  The image display medium according to claim 15 is the image display medium according to claim 14, wherein the first surface treatment unit having a higher affinity for the first medium than the second medium, and the first medium treated by the first medium. A second surface treatment unit having a higher affinity for the second medium, wherein the first surface treatment unit is disposed on a surface of the first electrode, and the second surface treatment unit includes the second surface treatment unit. It is arranged on the surface of the electrode.

  An image display device according to claim 16 is provided between the image display medium according to claim 14 or 15, the image display medium according to claim 14 or 15, and the first electrode and an electrode facing the first electrode. And an electric field control means for independently controlling the electric field generated between the second electrode and the electric field generated between the second electrode and the electrode facing the second electrode.

  The image display device according to claim 17 is the image display device according to claim 16, wherein the electric field control means applies voltages having different drive waveforms to the first electrode or the second electrode, respectively. The electric field is controlled independently.

  In addition, in claim 17, “applying voltages having different driving waveforms” includes applying voltages with driving waveforms having different amplitudes and / or applying driving waveforms having different pulse widths.

  The method for producing an image display medium according to claim 18, comprising a pair of substrates that are substantially spaced apart in parallel, a charged particle, and the charged particle, wherein the charged particle is interposed between the pair of substrates. An electrophoretic medium disposed, and an image display medium capable of switching a display state by moving the charged particles contained in the electrophoretic medium by an electric field generated between the pair of substrates In the method, the electrophoretic medium, which is a mixture of a first medium exhibiting a first color and a second medium exhibiting a second color capable of phase separation at least at room temperature with respect to the first medium, A medium disposing step of disposing at least one of the pair of substrates on a surface facing the other substrate, and the first medium and the second medium of the electrophoretic medium disposed by the medium disposing step By the phase separation from each other, and a medium separation step of forming a predetermined pattern by the first medium and the second medium.

  In addition, in claim 18, “disposing the electrophoretic medium on a surface of at least one of the pair of substrates facing the other substrate” means that one of the pair of substrates is one of the pair of substrates. The method includes both disposing the electrophoretic medium on the surface of the substrate facing the other substrate and disposing the electrophoretic medium between the pair of substrates.

  The image display medium manufacturing method according to claim 19 is the image display medium manufacturing method according to claim 18, wherein one of the pair of electrodes respectively provided on surfaces of the pair of substrates facing each other is separated. The first electrode and the second electrode are alternately arranged while being arranged, and the surface of the second electrode has a higher affinity for the second medium than the first medium. A surface treatment step of providing a first surface treatment section having a surface treatment section having a higher affinity for the first medium than the second medium on the surface of the first electrode; In the separation step, when the first medium and the second medium are phase-separated, the first medium becomes a position corresponding to the position of the first electrode, while the second medium is the second electrode. So that it corresponds to the position of And selectively placed so electrophoretic solvent, in which to form the predetermined pattern.

  The method for producing an image display medium according to claim 20 is the method for producing an image display medium according to claim 19, wherein the fluorine-containing compound is provided before the surface treatment of the first electrode and the second electrode in the surface treatment step. A protective film forming step of forming a liquid-resistant protective film on the surface of each of the pair of electrodes by applying a liquid containing a liquid.

  The method for manufacturing an image display medium according to claim 21 is the method for manufacturing an image display medium according to any one of claims 18 to 20, wherein the charged particles are applied to the first medium from the second medium. First particles having a higher affinity and second particles having a higher affinity for the second medium than the first medium.

  According to the image display medium of claim 1, the electrophoretic medium containing charged particles is disposed between a pair of substrates that are substantially spaced apart in parallel, and the pair of substrates is disposed between the pair of substrates. When an electric field is generated in the electrophoretic medium, the charged particles contained in the electrophoretic medium move, whereby the display state is switched. In such an image display medium, the electrophoretic medium includes: a first medium exhibiting a first color; and a second medium capable of phase separation at least at room temperature with respect to the first medium and exhibiting a second color. In the state in which the first medium and the second medium are phase-separated from each other, a predetermined pattern is formed. That is, according to the image display medium of the first aspect, at least at room temperature, the electrophoretic medium between the substrates has a predetermined pattern formed by the first medium and the second medium. Therefore, when the color of the first medium (first color) and the color of the second medium (second color) are different, or the colors of the first medium and the second medium are the same, When the colors of the charged particles contained in the medium are different, the image display medium can be displayed in multiple colors by forming a predetermined pattern so that one pixel can be formed by the adjacent first medium and second medium. There is an effect that can be made possible. In that case, since the first medium and the second medium constituting the electrophoretic medium are phase-separated at least at room temperature, such an image display medium capable of multicolor display can be easily obtained. In addition, in such an image display medium capable of multi-color display, the colors of the first medium and the second medium each serve as a color filter. Therefore, the image display medium is a reflective image display medium such as an electrophoretic method. Even in such a case, the brightness and color development are good, and as a result, there is an effect that the image quality can be kept high.

  According to the image display medium of the second aspect, in addition to the effect produced by the image display medium of the first aspect, the second medium has a surface that contacts the electrophoretic medium of at least one of the pair of substrates. The first surface treatment unit having a higher affinity for one medium and the second surface treatment unit having a higher affinity for the second medium than the first medium are arranged so as to correspond to a predetermined pattern. Therefore, by arranging the first medium and the second medium on the side of the substrate where the first processing unit and the second processing unit are arranged, the first medium and the second medium are respectively set to predetermined There is an effect that it is easy to selectively arrange at positions according to the pattern.

  According to the image display medium of claim 3, in addition to the effect exhibited by the image display medium of claim 1 or 2, the first medium and the second medium are each a solvent or the other that is insoluble with respect to the other. Therefore, there is an effect that the first medium and the second medium can be easily phase-separated.

  According to the image display medium of claim 4, in addition to the effect of the image display medium of claim 3, one of the first medium and the second medium is water or an aqueous solution, and the other is insoluble in water. Therefore, the first medium and the second medium can be easily phase-separated and one medium is water or an aqueous solution.

  According to the image display medium of claim 5, in addition to the effect of the image display medium of claim 4, since distilled water or deionized water is used as water, as an electrophoretic medium requiring insulation This is advantageous, and there is an effect that the quality as an image display medium can be improved.

  According to the image display medium of claim 6, in addition to the effect of the image display medium of claim 4 or 5, an aromatic hydrocarbon solvent, an aliphatic hydrocarbon solvent, a halogenated solvent as a water-insoluble solvent. Since any one of hydrocarbon solvent, silicone oil, or high-purity petroleum is used alone, or a mixture containing two or more of these is used, it is advantageous as an electrophoretic medium requiring insulation, and as an image display medium. There is an effect that quality can be improved.

  According to the image display medium of claim 7, in the image display medium according to any one of claims 1 to 6, the first particles having a surface having a more affinity for the first medium than the second medium; Since the second particles having a surface having a higher affinity for the second medium than the first medium are used as the charged particles, the first particles and the second particles are used as the first medium and the second medium, respectively. There is an effect that it is easy to selectively disperse in the medium. In addition, since the first particles or the second particles dispersed in one medium are difficult to move to the other medium, the first particles are mixed into the second medium, or the second particles are the first medium. It is possible to prevent the image quality from being mixed in, thereby maintaining the stability of the image quality.

  According to the image display medium of the eighth aspect, in addition to the effect exhibited by the image display medium of the seventh aspect, particles colored in different colors are used as the first particle and the second particle. When the colors exhibited by the first medium and the second medium are both transparent, there is an effect that multicolor display by the colors of the first particles and the second particles becomes possible. Further, in this case, since the colors of the first particles and the second particles each serve as a color filter, even in a reflection type image display medium such as an electrophoretic method, brightness and color development are good. As a result, there is an effect that the image quality can be kept high.

  According to the image display medium of the ninth aspect, in addition to the effect of the image display medium according to any one of the first to eighth aspects, the first medium and the second medium are colored in different colors. Multi-color display by the colors of the first medium and the second medium is possible. Therefore, there is an effect that an image display medium capable of multicolor display can be easily obtained. Further, in this case, since the colors of the first medium and the second medium each act as a color filter, even in a reflection type image display medium such as an electrophoretic method, brightness and color development are good. As a result, there is an effect that the image quality can be kept high.

  According to the image display medium of the tenth aspect, in addition to the effect exhibited by the image display medium according to any one of the first to ninth aspects, the pair of electrodes are respectively provided on the surfaces of the pair of substrates facing each other. Since a liquid-resistant protective film is provided on the surface of each electrode of the pair of electrodes, the liquid electrophoresis medium and the electrode are prevented from coming into direct contact with each other. Therefore, there is an effect that the deterioration of the electrode can be prevented.

  According to the image display medium of the eleventh aspect, in addition to the effect exhibited by the image display medium of the tenth aspect, the protective film containing the fluorine-containing compound is used as the liquid-resistant protective film, so that the liquid is liquid. Direct contact between the electrophoretic medium and the electrode can be more effectively prevented, whereby the electrode can be effectively prevented from deteriorating.

  According to the image display medium of the twelfth aspect, in addition to the effect exhibited by the image display medium according to any one of the first to eleventh aspects, the pair of substrates each have flexibility. There is an effect that the entire medium can be formed flexibly.

  According to the image display medium of the thirteenth aspect, in addition to the effect exhibited by the image display medium according to any one of the first to twelfth aspects, the distance between the pair of substrates is held by the spacer at a predetermined distance or more. Even when a force is applied to the substrate surface, it is possible to reliably prevent the substrate surface from being excessively distorted, so that the substrate can be reliably prevented from being damaged. In particular, when the substrate is a flexible substrate, it is possible to prevent the substrate and the substrate from being brought into contact with each other due to the slackness of the substrate, so that image quality deterioration and damage to the image display medium can be more reliably prevented. There is an effect that can be done.

  According to the image display medium of the fourteenth aspect, in addition to the effect produced by the image display medium according to any one of the tenth to thirteenth aspects, the first electrodes are alternately arranged while being separated from each other. The first medium is disposed at a position corresponding to the position of the first electrode, while the first medium is disposed at a position corresponding to the position of the second electrode; Since the predetermined pattern is formed, a pixel including the adjacent first medium and second medium can be formed. Therefore, when the color of the first medium (first color) and the color of the second medium (second color) are different, or the colors of the first medium and the second medium are the same, By making the colors of the charged particles contained in the medium different, there is an effect that the image display medium can be displayed in multiple colors.

  According to the image display medium of claim 15, in addition to the effect of the image display medium of claim 14, the first electrode has more affinity for the first medium than the second medium. Since the first surface treatment unit is provided and the second surface treatment layer having a higher affinity for the second medium than the first medium is provided on the second electrode, the first treatment on the substrate is performed. By placing the first medium and the second medium on the side where the parts and the second processing unit are arranged, the first medium and the second medium are selectively placed at positions according to a predetermined pattern, respectively. It is easy to arrange. Therefore, there is an effect that it is easy to dispose the first medium and the second medium at positions corresponding to the electrodes (first electrode and second electrode).

  An electrophoretic display device according to claim 16 is an electric field generated between a first electrode and an electrode facing the first electrode in the image display medium according to claim 14 or 15, and the second electrode. Since the electric field generated between the second electrode and the opposite electrode is controlled independently by the electric field control means, the medium disposed at the position corresponding to the first electrode and the second electrode respectively. Even with different media (first medium and second medium), the behavior (responsiveness) of the charged particles contained in the medium can be made uniform during image display or image erasure. Therefore, there is an effect that high quality display is possible.

  In the electrophoretic display according to claim 17, in addition to the effect produced by the electrophoretic display device according to claim 16, voltages having different drive waveforms are applied to the first electrode or the second electrode by the electric field control means. As a result, the electric fields are controlled independently of each other, so that the media arranged at the positions corresponding to the first electrode and the second electrode are different media (first media and second media). However, the behavior (responsiveness) of the charged particles contained in the medium can be made uniform during image display or image erasure. Therefore, there is an effect that high quality display is possible.

  According to the method for manufacturing an image display medium according to claim 18, the electrophoretic medium containing charged particles is disposed between a pair of substrates that are substantially spaced apart in parallel, and the pair When an electric field is generated between the substrates, the charged particles contained in the electrophoretic medium move, and thereby the first color is changed to produce an image display medium whose display state is switched. An electrophoretic medium that is a mixture of a first medium to be exhibited and a second medium that can be phase-separated at least at room temperature with respect to the first medium and that has a second color, At least one of the substrates is disposed on a surface facing the other substrate. Then, the first medium and the second medium in the electrophoretic medium arranged by the medium arrangement process are phase-separated from each other by the medium separation process, and a predetermined pattern is formed by the first medium and the second medium. Is done. Therefore, in the image display medium thus manufactured, the electrophoretic medium can be phase-separated at least at room temperature with respect to the first medium exhibiting the first color and exhibit the second color. In the state where the first medium and the second medium are phase-separated from each other, a predetermined pattern is formed. That is, according to the image display medium manufactured by the manufacturing method according to claim 18, the electrophoretic medium between the substrates has a predetermined pattern formed by the first medium and the second medium at least at room temperature.

  Therefore, when the color of the first medium (first color) and the color of the second medium (second color) are different, or the colors of the first medium and the second medium are the same, When the colors of charged particles contained in the medium are different, the image display medium can be displayed in multiple colors by forming a predetermined pattern that can form pixels including the adjacent first medium and second medium. There is an effect that can be made. In that case, since the first medium and the second medium constituting the electrophoretic medium are phase-separated at least at room temperature, such an image display medium capable of multicolor display can be easily obtained. In addition, in such an image display medium capable of multi-color display, the colors of the first medium and the second medium each serve as a color filter. Therefore, the image display medium is a reflective image display medium such as an electrophoretic method. Even in such a case, the brightness and color development are good, and as a result, there is an effect that the image quality can be kept high.

  According to the method for manufacturing an image display medium according to claim 19, in addition to the effect produced by the method for manufacturing an image display medium according to claim 18, the pair of substrates provided on the surfaces of the pair of substrates facing each other. One of the electrodes is composed of a first electrode and a second electrode that are alternately arranged while being separated from each other. By the surface treatment process, the surface of the first electrode is placed on the surface of the first electrode from the second medium. A first surface treatment layer having a higher affinity is provided, while a second surface treatment layer having a higher affinity for the second medium than the first medium is provided on the surface of the second electrode. . When the first medium and the second medium are phase-separated by the medium separation step, the first medium becomes a position corresponding to the position of the first electrode, while the second medium is the second electrode. Since the electrophoretic medium is selectively arranged so as to be a position corresponding to the position and a predetermined pattern is formed, a pixel including the adjacent first medium and second medium can be formed. Therefore, when the color of the first medium (first color) and the color of the second medium (second color) are different, or the colors of the first medium and the second medium are the same, By making the colors of the charged particles contained in the medium different, there is an effect that the image display medium can be displayed in multiple colors. Further, since the electrophoretic medium is selectively disposed by the first surface treatment layer and the second surface treatment layer, there is an effect that the production of the image display medium is easy.

  According to the method for manufacturing an image display medium according to claim 20, in addition to the effect exhibited by the method for manufacturing an image display medium according to claim 19, before the surface treatment of the first electrode and the second electrode by the surface treatment step. In the protective film forming step, the liquid containing the fluorine-containing compound is applied to form a liquid-resistant protective film on each surface of the pair of electrodes, so that the liquid electrophoresis medium and the electrode are directly Contact is more effectively prevented, and thereby, there is an effect that deterioration of the electrode can be more effectively prevented.

  According to the method for manufacturing an image display medium according to claim 21, in addition to the effect produced by the method for manufacturing an image display medium according to any of claims 18 to 20, the second medium is more effective than the first medium. Since the first particles having affinity and the second particles having higher affinity for the second medium than the first medium are used as charged particles, the first particles and the second particles are respectively There is an effect that it is easy to selectively disperse in the first medium and the second medium. In addition, since the first particles or the second particles dispersed in one medium are difficult to move to the other medium, the first particles are mixed into the second medium, or the second particles are the first medium. It is possible to prevent the image display medium from being mixed into the image display medium, thereby obtaining an image display medium capable of maintaining the stability of the image quality.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a diagram illustrating an image display medium 10 according to a first embodiment of the present invention. FIG. 1A is a perspective view of the entire display device 1 that displays an image on the image display medium 10. FIG. 1B is an exploded perspective view schematically showing the structure of the image display medium 10.

  As shown in FIG. 1A, the display device 1 is a device including an image display medium 10 and a main body 20, and by performing a predetermined operation after the image display medium 10 is arranged on the main body 20. An image can be displayed on the image display medium 10.

  The main body 20 includes a base plate 25 that is formed in a rectangular shape that is slightly larger than the size of the image display medium 10, and a frame body 26 that is attached along the periphery of the base plate 25. The frame body 26 is provided around the base plate 25 so that a part thereof (the left side of the base plate 25 in FIG. 1A) is opened. By providing the frame 26 with a part opened, the user can easily insert the image display medium 10 into the display device 1 and take out the image display medium 10 from the display device 1. The frame 26 has a drive control for controlling an electric signal (current, voltage, polarity) applied to the X electrode 12a and the Y electrode 13a (both see FIG. 1B) provided in the image display medium 10. A unit 70 (see FIG. 7) is included.

  A power switch 26a and operation buttons 26b are provided on the surface of the frame body 26. The power switch 26a is managed by a CPU 71 (see FIG. 7) included in the drive control unit 70 (see FIG. 7). When the CPU detects that the power switch 26a is turned on, the main body 20 is powered on. Supplied. The operation button 26 b is a button operated by the user in order to display an image on the image display medium 10.

  When the image display medium 10 is inserted into the display device 1 and disposed at a predetermined position on the base plate 25, the X electrode 12a and the Y electrode 13a (both see FIG. 1B) of the image display medium 10 are framed. The drive control unit 70 (see FIG. 7) included in the body 26 is connected. Then, when the user operates the operation button 26b, a desired image can be displayed on the image display medium 10 under the control of the drive control unit 70 (see FIG. 7).

  As shown in FIG. 1B, the image display medium 10 includes a first substrate 12, a second substrate 13, and a gap spacer 17 sandwiched between the second substrate 13 and the first substrate 12. Mainly provided, these are laminated. Although details will be described later with reference to FIG. 2, an electrophoretic medium 30 including charged particles 31 (both between the first substrate 12 and the second substrate 13, which are separated by the gap spacer 17) 2).

  Both the first substrate 12 and the second substrate 13 have a thickness of about 20 μm, and examples of the material thereof include glass, synthetic resin, natural resin, and paper. A preferable material of the first substrate 12 and the second substrate 13 is a synthetic resin exhibiting flexibility, for example, a polyester resin such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), or polyphenylene sulfide (PPS), Examples include aramid, polyimide, nylon, polypropylene, and hard polyethylene (high density polyethylene). Among these synthetic resins, polyethylene terephthalate, polyethylene naphthalate, and polyphenylene sulfide are particularly preferable materials in terms of transparency, strength, and heat resistance, and the most preferable material is polyethylene terephthalate. By using the above-described flexible material as the first substrate 12 and the second substrate 13, the entire image display medium 10 can exhibit flexibility.

  The first substrate 12 and the second substrate 13 are respectively provided with an X electrode 12a and a Y electrode 13a on the surfaces of the image display medium 10 facing each other. The X electrode 12a and the Y electrode 13a bear a polarity for applying an electric field to the electrophoretic medium 30 (see FIG. 2). Both the X electrode 12a and the Y electrode 13a are formed in a plurality of substantially parallel lines. Further, the X electrode 12 a and the Y electrode 13 a are configured to be substantially orthogonal to each other in the image display medium 10. That is, the image display medium 10 displays an image by a simple matrix driving method in which the electrodes 12a and 13a are turned on or off. The X electrode 12a includes an XA electrode 12a1 (see FIG. 2) and an XB electrode 12a2 (see FIG. 2), which are subjected to different electric field control by the drive control unit 70 (see FIG. 7). In FIG. 2B, the XA electrode 12a1 (see FIG. 2) and the XB electrode 12a2 (see FIG. 2) will be described later with reference to FIGS.

  As long as both the X electrode 12a and the Y electrode 13a have conductivity, the material is not particularly limited, and the material is not limited to metal, semiconductor, conductive resin, conductive paint, conductive ink, inorganic transparent conductor, and the like. It is comprised by the material of. The X electrode 12a and the Y electrode 13a are formed on the first substrate 12 and the second substrate 13, respectively, using the above-described materials by a known electroless plating method, sputtering method, vapor deposition method, ink jet method, or the like. Can be formed. In particular, when the material of the first substrate 12 and the second substrate 13 is a flexible synthetic resin, the substrate (by the inkjet method using an ink containing a conductive polymer such as a polythiophene-based conductive polymer) is used. The X electrode 12a and the Y electrode 13a can be easily formed without damaging the first substrate 12 and the second substrate 13).

  The gap spacer 17 is made of the synthetic resin, natural resin, ceramics, glass, or the like listed above as the material of the first substrate 12 and the second substrate 13, and an opening 17a is opened at the center thereof. Yes. The thickness of the gap spacer 17 is about 20 μm.

  Note that a liquid-resistant protective film 18 (see FIG. 2) and a surface treatment layer 19 (see FIG. 2) are formed on the surface of the first substrate 12 where the X electrode 12a is formed and the surface of the second substrate 13 where the Y electrode 13a is formed. In order to prevent the drawing from becoming complicated, the protective film 18 and the surface treatment layer 19 are not shown in FIG. 1B.

  Next, the structure of the image display medium 10 will be described more specifically with reference to FIG. FIG. 2 is a schematic cross-sectional view of the image display medium 10. Note that the cross-sectional view of FIG. 2 passes through one of the Y electrodes 13 a formed on the second substrate 13 and is substantially orthogonal to each of the X electrodes 12 a formed on the first substrate 12. The figure shows a cross section when cut along a cutting line.

  As shown in FIG. 2, the X electrodes 12a formed in a plurality of lines are each composed of a line XA electrode 12a1 and an XB electrode 12a2, and these electrodes 12a1 and 12a2 are alternately arranged. Yes. Each of the XA electrode 12a1 and the XB electrode 12a2 is paired with the opposing Y electrode 13a to generate an electric field between the first substrate 12 and the second substrate 13. Although details will be described later with reference to FIG. 7, voltages of different drive waveforms are applied to the XA electrode 12a1 and the XB electrode 12a2 by the control by the control unit 70 (see FIG. 7) included in the main body 20. The Therefore, different electric fields can be generated between the XA electrode 12a1 and the Y electrode 13a and between the XB electrode 12a2 and the Y electrode 13a.

  As will be described later, different types of media (the first medium 30a and the second medium 30b as the electrophoretic medium 30) are arranged at positions corresponding to the positions of the XA electrode 12a1 and the XB electrode 12a2, respectively. Yes. Therefore, different electric fields can be generated between the XA electrode 12a1 and the Y electrode 13a and between the XB electrode 12a2 and the Y electrode 13a, so that different media (the first medium 30a and the second medium 30b). The behavior (responsiveness) of the charged particles (the first particles 31a and the second particles 31b as the charged particles 31) dispersed therein can be made uniform.

  As shown in FIG. 2, an electrophoretic medium 30 including charged particles 31 that are positively or negatively charged is filled between the first substrate 12 and the second substrate 13 in the image display medium 10. The electrophoresis medium 30 includes a first medium 30a and a second medium 30b that are phase-separated from each other. As shown in FIG. 2, each of the first medium 30a and the second medium 30b has a line shape centered on one X electrode 12a of the X electrodes 12a formed in a plurality of lines. The first medium 30a and the second medium 30b are arranged in an alternating line (stripe shape). Specifically, the first medium 30a is disposed at a position corresponding to the XA electrode 12a1, while the second medium 30b is disposed at a position corresponding to the XB electrode 12a2.

  The first medium 30a and the second medium 30b that are the electrophoretic medium 30 are liquids (solvents or solutions) that are phase-separated from each other at least at the room temperature at which the image display medium 10 is operated and can maintain the phase-separated state. It is. In the case where the first medium 30a and the second medium 30b are phase-separated, it is most preferable that the boundary between both liquids is completely separated, but the boundary between both liquids is completely separated in appearance. However, it may be in a “substantially phase separated” state where both liquids are mixed in the boundary region. In addition, “phase separation” in the present specification and claims is not limited to the case where the boundary between both liquids is completely separated, but includes a state in which phases are substantially separated.

  As the preferable first medium 30a and the second medium 30b, the combination thereof is a combination of solvents that are insoluble with each other, a combination of solutions containing a solvent that is insoluble with each other, or a solvent that is insoluble with each other. And a solution containing a solvent insoluble in each other. In such a combination of the first medium 30a and the second medium 30b, the first medium 30a is water or an aqueous solution, and the second medium 30b includes a solvent that is insoluble in water or a solvent that is insoluble in water. More preferably, it is a solution.

  When water or an aqueous solution is used as the first medium 30a, it is preferable to use water that does not contain an ionic substance and has high electrical resistance (high insulation), and particularly preferably distilled water or ion-exchanged water. .

  When a solvent that is insoluble in water is used as the second medium 30b, a solvent having high electric resistance (high insulation) is preferable, for example, an aromatic hydrocarbon solvent (for example, benzene, toluene, xylene, etc.), fat Group hydrocarbon solvents (for example, linear or cyclic paraffinic hydrocarbon solvents such as hexane and cyclohexane, isoparaffinic hydrocarbon solvents, kerosene, etc.), halogenated hydrocarbon solvents (for example, chloroform, trichloroethylene, dichloromethane, trichlorotrifluoroethylene) , Ethyl bromide, etc.), an oily polysiloxane such as silicone oil, or high-purity petroleum. A particularly suitable second medium 30b is an aliphatic hydrocarbon solvent. Suitable examples of the second solvent 30b include, for example, Isopar G, H, M, and L (all manufactured by ExxonMobil), Shellsol (manufactured by Showa Shell Japan), IP solvent 1016, 1620, 2028, and 2835 (all of which are Idemitsu). Petrochemical). In the present specification and claims, the “solvent that is insoluble in water” includes each of the organic solvents listed above alone and a mixture of two or more organic solvents. .

  In the present embodiment, the first medium 30a and the second medium 30b are colored in different colors (for example, red and blue), respectively. The colored first medium 30a and second medium 30b can be prepared by appropriately dissolving various dyes that are soluble in the respective media 30a and 30b.

  When the charged particles 31 (first particles 31a) dispersed in the first medium 30a are migrated to the surface opposite to the surface that is visually recognized by the user (hereinafter referred to as “viewing surface”). The user will visually recognize the color (for example, blue) of the first medium 30a. Similarly, when the charged particles 31 (second particles 31b) dispersed in the second medium 30b are migrated to the surface opposite to the viewing surface, the user can select the color of the second medium 30b (for example, (Red) will be visually recognized. In the following description, it is assumed that the user visually recognizes the image display medium 10 from the direction of the arrow V, that is, the substrate 12 is a viewing surface.

  That is, in the image display medium 10, the colors colored on the first medium 30a and the second medium 30b serve as a color filter. Therefore, the image display medium 10 of the present embodiment can perform multicolor display. In addition, since multicolor display is performed using the colors of the first medium 30a and the second medium 30b, a reflective image display medium such as an electrophoretic method is used, compared to a case where a color filter layer is separately provided on the viewing surface side. Even so, the screen is bright and the color is good.

  The charged particles 31 are composed of first particles 31a dispersed in the first medium 30a and second particles 31b dispersed in the second medium 30b, both of which are positively (or negatively) charged. White or light colored particles.

  The second particles 31b have a surface that is more compatible with the second medium 30b than with the first medium 30a. Therefore, the second particles 31b are selectively dispersed not in the first medium 30a but in the second medium 30b. Since the second particles 31b selectively dispersed in the second medium 30b are suppressed from being mixed into the first medium 30a, the charged particles 31 dispersed in the electrophoretic medium 30 are less likely to be biased. , The stability of image quality can be maintained.

  Here, when the first medium 30a is water or an aqueous solution and the second medium 30b is a solution containing a solvent insoluble in water or a solvent insoluble in water, the second particles 31b are hydrophilic. Polymer particles having a surface exhibiting hydrophobicity (lipophilicity) rather than property, for example, polymer particles composed of a polymer having a hydrophobic surface are used. Examples of the polymer having a hydrophobic surface include styrene resins, acrylic resins, styrene-acrylic copolymers, and polyester resins. Specifically, NATCO SPACER (manufactured by NATCO Corporation), EPOCOLOR (manufactured by Nippon Shokubai Chemical Co., Ltd.), Chemisnow (manufactured by Soken Chemical Co., Ltd.), Tospearl (manufactured by GE Toshiba Silicon Corporation), Techpolymer ( Sekisui Plastics Industry Co., Ltd.).

  On the other hand, the 1st particle 31a has the surface which shows more affinity with respect to the 1st medium 30a than the 2nd medium 30b. Therefore, the first particles 31a are selectively dispersed not in the second medium 30b but in the first medium 30a. Since the first particles 31a selectively dispersed in the first medium 30a are suppressed from being mixed into the second medium 30b, the charged particles 31 dispersed in the electrophoretic medium 30 are not easily biased. , The stability of image quality can be maintained.

  Here, when the first medium 30a is water or an aqueous solution, and the second medium 30b is a solution insoluble in water or a solution containing a solvent insoluble in water, the first particles 31a are hydrophobic. Particles having a surface that is more hydrophilic than the property, for example, particles in which fine particles of a hydrophilic substance such as titanium dioxide or silica are attached to the surface of the resin having the hydrophobic surface listed above as the second particles 31b, Alternatively, particles in which a film made of the hydrophilic substance is formed, polymer particles composed of a polymer having a hydrophilic surface, or the like is used. Polymers having a hydrophilic surface can be obtained, for example, by copolymerization polymerized using acrylamide and hydroxymethyl acrylate as monomers, or by dispersion polymerization of methyl methacrylate using poly (oxyethylene) macromonomer as a reactive dispersion stabilizer. And particles obtained by graft polymerization of the hydrophilic acrylic acid monomer or hydrophilic (meth) acrylic monomer on the surface of the polymer particles.

  The first particles 31a and the second particles 31b are formed on the first substrate 12 side or on the first substrate 12a according to the electric field generated between the X electrode 12a (XA electrode 12a1, XB electrode 12a2) and the Y electrode 13a, respectively. 2 migrate to the substrate 13 side. Here, in the image display medium 10, the first particles 31 a are generated by an electric field generated independently between one intersecting X electrode 12 a and Y electrode 13 a in the X electrode 12 a and the Y electrode 13 a having a lattice shape. Alternatively, the region where the second particles 31b migrate independently is the smallest particle migration region (hereinafter referred to as “minimum particle migration region”).

  More specifically, when an electric field is formed so that the potential of the X electrode 12a is positive with respect to the potential of the Y electrode 13a in one minimum particle migration region, the charged particles are positively charged. 31 (first particle 31a or second particle 31b) migrates to the second substrate 13 side (Y electrode 13a side). In this case, the user visually recognizes the color of the electrophoresis medium 30 arranged in the minimum particle migration region. That is, in the minimum particle migration region where the charged particles 31 migrate to the second substrate 13 side, the electrophoretic medium 30 arranged in the minimum particle migration region is the first medium 30a colored in blue. Will see blue. On the other hand, when the electrophoretic medium 30 disposed in such a minimum particle migration region is the second medium 30b colored red, the user visually recognizes red. In the present embodiment, the state of the minimum particle migration region where the color for coloring the electrophoretic medium 30 is visually recognized when the user visually recognizes the viewing surface is referred to as a “display state”.

  On the other hand, when an electric field is formed in one minimum particle migration region so that the potential of the X electrode 12a is negative with respect to the potential of the Y electrode 13a, the charged particles 31 (the first charged) One particle 31a or second particle 31b) migrates to the first substrate 12 side (X electrode 12a side). In this case, the user visually recognizes the white or light color that is the color of the charged particles 31. In the present embodiment, the state of the minimum particle migration region that is visually recognized as white when the user visually recognizes the viewing surface is referred to as a “non-display state”.

  When the charged particle 31 is negatively charged, the X electrode 12a is positive with respect to the Y electrode 13a in one minimum particle migration region, contrary to the case where the charged particle 31 is positively charged. When the electric field is formed so that the minimum particle migration region is in a non-display state, and when the electric field is formed so that the X electrode 12a is negative with respect to the Y electrode 13a, the minimum particle migration region is Display state.

  In the image display medium 10, as described above, the colored colors of the first medium 30a and the second medium 30b serve as color filters. Therefore, the group of the minimum particle migration region of the first medium 30a and the minimum particle migration region of the second medium 30b adjacent to each other is defined as one pixel, and the migration of the charged particles 31 (the first particles 31a and the second particles 31b) is performed. By controlling, it is possible to perform multicolor display on the image display medium 10 by controlling the subtractive color combination of two colors in one pixel. Note that it is sufficient that one pixel includes at least one minimum particle migration region of the first medium 30a and one minimum particle migration region of the second medium 30b. One pixel may be formed.

  As shown in FIG. 2, a protective film 18 is provided on the surfaces of the X electrode 12 a and the Y electrode 13 a in the image display medium 10. Since the protective film 18 prevents direct contact between the electrophoretic medium 30 that is a liquid and the electrodes (X electrode 12a and Y electrode 13a), the electrodes (X electrode 12a and Y electrode 13a) in the image display medium 10 are prevented. Deterioration can be prevented. The protective film 18 is preferably a film containing a fluorine-containing compound from the viewpoint of excellent water repellency, oil repellency, corrosion resistance, chemical resistance, and the like.

  Here, the fluorine-containing compound is preferably a fluorine-containing compound that becomes liquid at a predetermined temperature or higher. For example, low molecular weight polytetrafluoroethylene (low molecular weight PTFE), low molecular weight polychlorotrifluoroethylene (low Molecular weight PCTFE), low molecular weight tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (low molecular weight PFA), low molecular weight tetrafluoroethylene / hexafluoropropylene copolymer (low molecular weight FEP), and the like.

  The protective film 18 is made into a liquid state by heating the fluorine-containing compound as described above to a predetermined temperature or higher, and the liquid is applied to the electrode (X electrode 12a) on the substrate (the first substrate 12 or the second substrate 13). Alternatively, it is formed by a step of uniformly applying to the surface on the side where the Y electrode 13a) is provided and then drying (this step is referred to as a “protective film forming step”).

  In the protective film forming step, as a method for applying the fluorine-containing compound onto the substrate (the first substrate 12 or the second substrate 13), a method such as a dipping method, a sol-gel method, or a spray method can be used. In addition, the fluorine-containing compound used for forming the protective film 18 may be a fluorine-containing compound that can be applied by dissolving or dispersing in a solvent. In that case, the fluorine-containing compound is dissolved or dissolved. A protective film forming step similar to the above may be performed using the dispersed liquid.

  As shown in FIG. 2, a surface treatment layer 19 is provided as a layer in contact with the electrophoretic medium 30 and the partition wall medium 32 on the first substrate 12 that is a substrate to be a viewing surface. The surface treatment layer 19 includes a first surface treatment layer 19a and a second surface treatment layer 19b.

  As shown in FIG. 2, the exposed portions of the first surface treatment layer 19a and the second surface treatment layer 19b are disposed at positions corresponding to the positions where the first medium 30a and the second medium 30b are disposed, respectively. Although not shown in particular, the exposed portions of the first surface treatment layer 19a and the second surface treatment layer 19b are formed in stripes along the line-shaped XA electrodes 12a1 and XB electrodes 12a2, respectively.

  The first surface treatment layer 19a is a layer in which at least the surface in contact with the electrophoretic medium 30 is more compatible with the first medium 30a than the second medium 30b, while the second surface treatment layer 19b is At least the surface in contact with the electrophoretic medium 30 is a layer having a higher affinity for the second medium 30b than for the first medium 30a. For example, when the first medium 30a is water or an aqueous solution and the second medium 30b is a solvent insoluble in water or a solution containing the solvent, the first surface treatment layer 19a exhibits so-called “hydrophilicity”. On the other hand, the second surface treatment layer 19b is a layer having a surface exhibiting so-called “hydrophobic (or lipophilic)”.

  Therefore, when the first medium 30a and the second medium 30b are phase-separated, the first medium 30a having a higher affinity than the second medium 30b is disposed on the first surface treatment layer 19a. On the other hand, it is the most stable state in terms of energy that the second medium 30b having higher affinity than the first medium 30a is disposed on the second surface treatment layer 19b. Accordingly, by providing the first surface treatment layer 19a and the second surface treatment layer 19b, the first medium 30a and the second medium 30b that are phase-separated from each other can be replaced with the first surface treatment layer 19a and the second surface treatment layer 19b, respectively. It becomes easy to selectively arrange on top. In addition, the first medium 30a and the second medium 30b that have been phase-separated at a predetermined position between the substrates 12 and 13 are mixed again by an external factor (for example, the substrates 12 and 13 are pressed). Even if it exists, these media 30a and 30b are again arrange | positioned on the 1st surface treatment layer 19a or the 2nd surface treatment layer 19b, respectively.

  In addition, it is preferable to provide the surface treatment part 19 (the 1st surface treatment layer 19a and the 2nd surface treatment layer 19b) in the 1st board | substrate 12 side which is a visual recognition surface like a present Example. By providing the first surface treatment layer 19a and the second surface treatment layer 19b on the first substrate 12 side, the first medium 30a and the second medium 30b can be clearly distinguished. Moreover, when providing the surface treatment part 19 in the 1st board | substrate 12 side which is a visual recognition surface side, it is preferable that it is transparent so that an image display may not be prevented.

  Next, a method for forming the surface treatment layer 19 (referred to as “surface treatment step”) will be illustrated with reference to FIGS. 3 and 4. FIG. 3 is a diagram for explaining a first example of the surface treatment process, and FIG. 4 is a diagram for explaining a second example of the surface treatment process.

  A first example of the surface treatment step described with reference to FIG. 3 is a hydrophilic polymer in which the irradiated portion is selectively changed to hydrophobicity by irradiation with an infrared laser (hereinafter referred to as “thermal phase conversion type hydrophilic polymer”). It is a method of using. This method is a known method often used in the printing industry (for example, SP plateless DOP technology of Creo).

  FIG. 3A is a diagram showing a state before the first surface treatment layer 19a is formed after the protective film formation step, and FIG. 3B is a diagram showing that the first surface treatment layer 19a is the protective layer 18. It is a figure which shows the 1st board | substrate 12 provided on the top. The first surface treatment layer 19a is formed by applying a heat-sensitive phase conversion type hydrophilic polymer on the protective layer 18 by a spray method or the like.

  FIGS. 3C to 3E are views for explaining the formation of the second surface treatment layer 19b by irradiation with an infrared laser. When the first surface treatment layer 19a is provided on the protective layer 18, as shown in FIG. 3C, the metal mask 40 having a plurality of substantially rectangular openings 40a having a predetermined width is formed on the first surface. It arrange | positions above the process layer 19a. At that time, the position where the opening 40a is desired to form the second surface treatment layer 19b, that is, the opening 40a is substantially parallel to the longitudinal direction of the XB electrode 12a2, and the XB electrode is located at the approximate center in the width direction. The metal mask 40 is arranged so as to be approximately in the center in the width direction of 12a2.

  Next, as shown in FIG. 3D, the first surface treatment layer 19a is irradiated with an infrared laser through the metal mask 40 in the direction of the arrow. When the first surface treatment layer 19a is irradiated with an infrared laser, a second surface treatment layer 19b that is hydrophobic is formed in the portion exposed through the opening 40a as shown in FIG. The As described above, the opening portion 40a of the metal mask 40 is disposed so that the longitudinal direction thereof and the XB electrode 12a2 are substantially parallel, and is approximately at the center in the width direction of the XB electrode 12a2. ing. Therefore, when the infrared laser is irradiated, the surface (exposed surface) of the surface treatment layer 19 is centered on the second surface treatment layer 19b, which is a line having a predetermined width centered on the XB electrode 12a2, and the XA electrode 12a1. The exposed portion of the first surface treatment layer 19a, which is a line having a predetermined width, is formed in a stripe shape alternately arranged.

  A second example of the surface treatment process described with reference to FIG. 4 is a method of ablating (burning out) the hydrophilic surface layer of the layered body for ablation by irradiation with an infrared laser to expose the hydrophobic layer. It is. This method is also a well-known method often used in the printing industry (for example, RETALwet of Presstek).

  FIG. 4A is a diagram showing a state before the layered body for ablation is formed after the protective film forming step. FIG. 4B is a view showing the first substrate 12 in which the layered body for ablation is disposed on the protective film 18. The layered body for ablation includes a first surface treatment layer 19a that is a hydrophilic polymer, a second surface treatment layer 19b that is a hydrophobic film, a second surface treatment layer 19b, and a first surface treatment layer 19a. It is a layered body consisting of three layers with the metal exfoliation layer 16 arranged between the two. As shown in FIG. 4B, the layered body for ablation is arranged so that the second surface treatment layer 19 b is on the protective film 18.

  4C to 4E are views for explaining the formation of the surface treatment layer 19 by irradiation with an infrared laser. When the layered body for ablation is disposed on the protective film 18, as shown in FIG. 4C, the metal mask 40 provided with a plurality of substantially rectangular openings 40a having a predetermined width is formed on the first surface. It arrange | positions above the process layer 19a. At that time, the position where the opening 40a is desired to form the second surface treatment layer 19b, that is, the opening 40a is substantially parallel to the longitudinal direction of the XB electrode 12a2, and the XB electrode is located at the approximate center in the width direction. The metal mask 40 is arranged so as to be approximately in the center in the width direction of 12a2.

  Next, as shown in FIG. 4D, the layered body for ablation is irradiated with an infrared laser through the metal mask 40 in the direction of the arrow. When the layered body for ablation is irradiated with an infrared laser, the exposed portion of the first surface treatment layer 19a and the metal strip layer 16 are ablated (burned off) through the opening 40a, and FIG. As shown in e), the hydrophobic second surface treatment layer 19b is exposed. As described above, the opening portion 40a of the metal mask 40 is disposed so that the longitudinal direction thereof and the XB electrode 12a2 are substantially parallel, and is approximately at the center in the width direction of the XB electrode 12a2. ing. Therefore, when the infrared laser is irradiated, the surface (exposed surface) of the surface treatment layer 19 is centered on the first surface treatment layer 19a that is a line having a predetermined width centered on the XA electrode 12a1 and the XB electrode 12a2. The second surface treatment layer 19b exposed by a line having a predetermined width is formed in a stripe shape alternately arranged.

  According to the method shown in FIG. 3 or FIG. 4 as described above, the pattern (shape) of the first surface treatment layer 19a and the second surface treatment layer 19b is changed by changing the shape and position of the opening 40a of the metal mask 40. And the arrangement) can be easily changed as necessary. For example, the substantially rectangular first surface treatment layer 19a and second surface treatment layer 19b can be arranged as a checkered pattern.

  The method for providing the surface treatment layer 19 is not limited to the above method. For example, a polymer having a higher affinity for the first medium 30a than the second medium 30b is applied in a line shape around the XA electrode 12a1 using a roller or the like, while the first medium 30a The surface treatment layer 19 is provided by various methods such as a method of applying a polymer having a higher affinity for the second medium 30b to a line centered on the XB electrode 12a2 using a roller or the like. You can also.

  Next, a method for arranging the electrophoretic medium 30 between the substrates (the first substrate 12 and the second substrate 13) of the image display medium 10 will be described with reference to FIGS. FIG. 5 is a diagram schematically illustrating the preparation of the electrophoretic medium 30 including the charged particles 31, and FIG. 6 illustrates the case where the electrophoretic medium 30 including the charged particles 31 is the substrate of the image display medium 10 (the first substrate 12). , 2nd substrate 13) It is a figure explaining the process until it arrange | positions between.

  In order to prepare the electrophoretic medium 30 including the charged particles 31 used in this embodiment, first, the first particles 31a having a surface having a higher affinity for the first medium 30a than the second medium 30b are dispersed. In addition, when the first medium 30a (hereinafter, this dispersion is referred to as "dispersion Da"), the second particles 31b having a surface having a higher affinity for the second medium 30b than the first medium 30a are dispersed. Second medium 30b (hereinafter, this dispersion is referred to as “dispersion Db”) is prepared. Next, the dispersion liquid Da and the dispersion liquid Db are mixed and sufficiently stirred, thereby producing an emulsion in which the second medium 30b is dispersed in the first medium 30a as shown in the lower part of FIG.

  The electrophoretic medium 30 including the charged particles 31 thus emulsified (hereinafter, the emulsion of the electrophoretic medium 30 including the charged particles 31 is referred to as “emulsion E”) will be described with reference to FIG. It arrange | positions between the board | substrates 12 and 13 like this. 5 shows an emulsion in which the second medium 30b is dispersed in the first medium 30a as the emulsion E, it may be an emulsion in which the first medium 30a is dispersed in the second medium 30b.

  The emulsion E prepared as described above is arranged between the substrates 12 and 13 by the medium arrangement process. As shown in the upper part of FIG. 6, the medium arranging step includes a cell C (a first substrate 12 having a surface treatment layer 19 as the uppermost layer, a gap spacer 17, and a protective film 18 as the uppermost layer, as shown in the upper part of FIG. 6. This is performed by injecting the emulsion E from an injection port (not shown) provided in the device) using a dispenser or the like.

  After the emulsion E is injected into the cell C by the medium arrangement process, the injection port (not shown) is sealed, and then the medium separation process is performed. In the medium separation step, the first medium 30a and the second medium 30b are selected at positions corresponding to the XA electrode 12a1 and the XB electrode 12a2, respectively, by spontaneously phase-separating the emulsion E injected into the cell C. Can be arranged. More specifically, the first medium 30a and the second medium 30b are respectively separated into the first surface treatment layer 19a and the second surface treatment layer 19b by spontaneously phase-separating the emulsion E injected into the cell C. Is selectively placed on the top. Further, when the emulsion E is phase-separated into the first medium 30a and the second medium 30b, the first particles 31a having a surface having a higher affinity for the first medium 30a than the second medium 30b are obtained. The second particles 31b having a surface selectively dispersed in the first medium 30a and having a higher affinity for the second medium 30b than the first medium 30a are selectively dispersed in the second medium 30b. Is done.

  Therefore, according to the method of the present embodiment, the spontaneous phase separation between the first medium 30a and the second medium 30b and the difference in affinity with the first surface treatment layer 19a or the second surface treatment layer 19b are obtained. Since the arrangement of the used selective media 30a and 30b is used, the image display medium 10 of this embodiment can be easily manufactured by a simple method.

  Next, control for displaying an image on the image display medium 10 having the above configuration will be described with reference to FIG. FIG. 7 is a block diagram showing an electrical configuration of the display device 1 that is a device for displaying an image on the image display medium 10.

  The display device 1 includes an image display medium 10 including an XA power source 12a1, an XB power source 12a2, and a Y power source, and a main body 20. The main body 20 includes a control unit 70 that controls image display on the image display medium 10. The control unit 70 includes a CPU 71 that is a central processing unit, a ROM 72, a RAM 73, a storage device 74, and an image. Interface 75 (image I / F 75), Y pulse voltage control circuit 76, Y drive power supply 77 for supplying voltage to Y pulse voltage control circuit 76, X pulse voltage control circuit 78, and X pulse voltage control circuit And an X drive power supply 79 for supplying a voltage to 78.

  The ROM 72 is a non-rewritable memory that stores control programs executed by the CPU 71 and data necessary for the CPU 71 to execute these control programs. The control program stored in the ROM 72 applies a voltage based on the image data stored in the RAM 73 or the storage device 74 to the XA power source 12a1, the XB power source 12a2, and the Y electrode 13a that form a predetermined line. Is programmed.

  The RAM 73 is a volatile memory for temporarily storing data and programs necessary for various processes executed by the CPU 71 and temporarily storing image data input from the outside via an interface (not shown). Memory. The storage device 73 is a non-volatile memory such as a hard disk, and stores image data input from the outside via an interface (not shown). Note that image data stored in the RAM 73 and the recording device 74 is processed by the CPU 71 and output to the image I / F 74 as pixel data.

  The image I / F 74 performs each process such as a correction process in consideration of the electrical resistance and viscosity of the first medium 30a and the second medium 30b on the pixel data input from the RAM 73 or the recording device 74 via the CPU 71. , An interface for outputting to the Y pulse voltage control circuit 76 and the X pulse voltage control circuit 78.

  The Y pulse voltage control circuit 76 converts the voltage supplied from the Y drive power supply 77 into a drive pulse according to a signal output from the image I / F 74 and outputs the drive pulse to the Y electrode 13a.

  The X pulse voltage control circuit 78 converts the voltage supplied from the X drive power supply 79 into a drive pulse according to a signal output from the image I / F 74, and outputs the drive pulse to the XA electrode 12a1 and the XB electrode 12a2. In this case, as a result of the correction processing performed on the image I / F 74, different drive pulses corresponding to the characteristics of the first medium 30a and the second medium 30b are output to the XA electrode 12a1 and the XB electrode 12a2.

  The Y pulse voltage control circuit 76 and the X pulse voltage control circuit 78 apply a voltage to the Y electrode 13a, the XA electrode 12a1, and the XB electrode 12a2, and the Y electrode 13a, the XA electrode 12a1, and the XB electrode in the image display medium 10 are applied. An electric field is formed between 12a2.

  In the image display medium 10 of the present embodiment, two types of media, the first medium 30 a and the second medium 30 b, are used as the electrophoretic medium 30. If the medium is different, there is a difference in electric resistance, viscosity, and the like. Therefore, when the same drive pulse is applied to the XA electrode 12a1 and the XB electrode 12a2, the first particles 31a and the second medium 30b included in the first medium 30a. There may be a difference in behavior (responsiveness) between the second particles contained in the.

  However, in the display device 1, the application of voltage to the XA electrode 12a1 and the XB electrode 12a2 can be controlled independently, so that different media (first medium 30a, second medium 30b) are used for the image display medium 10. Even in this case, the same electric field is generated between the Y electrode 13a and the X electrode 12a (XA electrode 12a1, XB electrode 12a2) by outputting different driving pulses according to the characteristics of the first medium 30a and the second medium 30b. Can be generated. Therefore, since the behavior (responsiveness) of the first particles 31a and the second particles can be made uniform, high-quality display is possible.

  As described above, in the image display medium 10 of the first embodiment, the electrophoretic medium 30 can be phase-separated at least at room temperature with respect to the first medium 30a exhibiting the first color and the first medium 30a. Since it is composed of the second medium 30b exhibiting the second color, the area of the first medium 30a and the area of the second medium 30b can be formed independently.

  In this case, the first surface region 19a having an affinity for the first medium 30a from the second medium 30b and the second medium from the first medium 30a are on the surface contacting the first medium 30a and the second medium 30b. By providing the second surface region 19b having affinity for 30b in a pattern alternately arranged in a line centering on the XA electrode 12a1 and the XB electrode 12a2, respectively, the first medium 30a and the second medium 30b can be easily and selectively arranged in a line shape centered on the XA electrode 12a1 and the XB electrode 12a2, respectively. That is, the image display medium 10 capable of multicolor display can be easily manufactured by a simple method.

  In this way, the first medium 30a and the second medium 30b are selectively arranged in a line centered on the XA electrode 12a1 and the XB electrode 12a2, so that the color of the first medium 30a is as in this embodiment. When the (first color) and the color (second color) of the second medium 30b are different, the adjacent first medium and second medium constitute one pixel, thereby making the image display medium 10 Multi-color display is possible. In this case, the color of the first medium 30a (first color) and the color of the second medium 30b (second color) serve as a color filter. Even in this image display medium, the brightness and color development are good, and as a result, the image quality can be kept high.

  Further, the display device 1 of the first embodiment can independently control the application of voltage to the XA electrode 12a1 and the XB electrode 12a2. Therefore, even when different media (the first medium 30a and the second medium 30b) are used as the image display medium 10, by outputting different driving pulses according to the characteristics of the first medium 30a and the second medium 30b, A similar electric field can be generated between the Y electrode 13a and the X electrode 12a (XA electrode 12a1, XB electrode 12a2). As a result, since the behavior (responsiveness) of the first particles 31a and the second particles can be made uniform, high-quality display is possible.

  Next, the image display medium 10 in the second embodiment will be described. In the second embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  The image display medium 10 according to the first embodiment performs multicolor display using the first medium 30a and the second medium 30b colored in different colors. On the other hand, in the image display medium 10 of the second embodiment, the first medium 30a and the second medium 30b are both the same color, and the first particles 31a and the second particles 31b colored in different colors are used. Multi-color display is performed.

  The image display medium 10 of the second embodiment is the same as the first embodiment except that the colors of the first medium 30a and the second medium 30b are the same, and the colors of the first particles 31a and the second particles 31b are different. It has a configuration. The colors of the first medium 30a and the second medium 30b used in the image display medium 10 of the second embodiment are preferably white or light.

  In the image display medium 10 of the second embodiment, when the colored charged particles 31 (the first particles 31a and the second particles 31b) are migrated to the viewing surface (substrate 12) side, the user You will see the color. That is, when the charged particles 31 (first particles 31a) dispersed in the first medium 30a are migrated to the viewing surface side, the user visually recognizes the color (for example, blue) of the first particles 31a. In other words, when the charged particles 31 (second particles 31b) dispersed in the second medium 30b are migrated to the viewing surface side, the user changes the color (for example, red) of the second particles 31b. You will see. In the second embodiment, this state is the display state.

  On the other hand, when the colored charged particles 31 (the first particles 31a and the second particles 31b) migrate to the surface opposite to the viewing surface, the user can select the color of the first medium 30a or the second medium 30b (for example, White). In the second embodiment, this state is a non-display state.

  Therefore, as in the second embodiment, the color of the first medium 30a and the color of the second medium 30b are the same, but the color of the first particles 31a and the color of the second particles 31b included in those media When the image display medium 10 is different, the image display medium 10 can be displayed in multiple colors by forming one pixel with the adjacent first medium 30a and second medium 30b as in the first embodiment. Can do.

  In the image display medium 10 of the second embodiment, since the multicolor display is performed using the colors of the first particles 31a and the second particles 31b, compared with the case where a color filter layer is separately provided on the viewing surface side, the electric display is performed. Even a reflection-type image display medium such as an electrophoretic method has a bright screen and good color development.

  Similarly to the first embodiment, the image display medium 10 of the second embodiment applies voltage to the XA electrode 12a1 and the XB electrode 12a2 by the control unit 70 included in the main body 20 of the display device 1. Each is controlled independently. Therefore, even when different media (the first medium 30a and the second medium 30b) are used as the image display medium 10, by outputting different driving pulses according to the characteristics of the first medium 30a and the second medium 30b, A similar electric field can be generated between the Y electrode 13a and the X electrode 12a (XA electrode 12a1, XB electrode 12a2). As a result, since the behavior (responsiveness) of the first particles 31a and the second particles can be made uniform, high-quality display is possible.

  The present invention has been described above based on the embodiments. However, the present invention is not limited to the above-described embodiments, and various modifications and changes can be easily made without departing from the spirit of the present invention. Can be inferred.

  For example, in the above embodiment, the electrodes provided on the image display medium 10 are of the simple matrix driving method, but the active matrix driving method is a method of applying a voltage directly by providing a semiconductor switch for each pixel. It may be applied.

  Further, in the above embodiment, only the gap spacer 17 is interposed between the first substrate 12 and the second substrate 13, but when the cell C is assembled, the first substrate 12 and the second substrate A particulate spacer may be added between the substrate 13 and the substrate 13. By adding the particulate spacer, the image display medium 10 can hold the distance between the first substrate 12 and the second substrate 13 at a predetermined distance or more due to the presence of the particulate spacer.

  Therefore, even if a force is applied to the surface of the first substrate 12 or the second substrate 13, it is possible to reliably prevent the surface from being excessively distorted, so that the first substrate 12 or the second substrate 13 is damaged. Can be surely prevented. In particular, when the first substrate 12 and the second substrate 13 are flexible, the first substrate 12 and the second substrate 13 can be reliably prevented from coming into contact with each other due to the looseness of the substrate. It is possible to reliably prevent image quality deterioration and damage to the image display medium.

  Note that instead of the particulate spacer, a partition wall fixed to one substrate side but separated from the other substrate side, or a partition wall having a communication portion may be provided.

  In the above embodiment, after assembling the cell C, the emulsion E is injected as the medium arranging step. Instead, the emulsion E is applied on the first substrate 12 having the surface treatment unit 19 as the medium arranging step. Next, as a medium separation process, the emulsion E is spontaneously phase-separated as a medium separation step, and the first medium 30a and the second medium 30b are positioned corresponding to the XA electrode 12a1 and the XB electrode 12a2, respectively. You may comprise so that it may arrange | position selectively. In this case, it is assumed that the gap spacer 17 is already laminated on the first substrate 12 to which the emulsion E is applied in the medium arranging step, and after the medium arranging step, the second substrate 13 is overlapped so that no bubbles enter, The periphery is sealed to obtain the image display medium 10.

  Moreover, in the said Example, although the surface treatment part 19 was comprised so that it might be provided only in one board | substrate (1st board | substrate 12), it should be provided in both board | substrates (1st board | substrate 12 and 2nd board | substrate 13). Also good. In addition, the first surface treatment unit 19a and the second surface treatment unit 19b are separately provided, for example, the first substrate 12 is provided with the first surface treatment unit 19a and the second substrate 13 is provided with the second surface treatment unit 19b. You may comprise so that it may be provided on a board | substrate.

  Moreover, in the said Example, although the surface treatment part 19 was comprised so that it might provide in the 1st board | substrate 12 which is a visual recognition surface, you may comprise so that it may provide in the 2nd board | substrate 13.

  Moreover, in the said Example, when the 1st medium 30a and the 2nd medium 30b are mutually different colors (1st Example), so that the 1st particle 31a and the 2nd particle 31b may be the same color. On the other hand, when the first medium 30a and the second medium 30b are the same color (second embodiment), the first particle 31a and the second particle 31b are different from each other. did. In addition, the first medium 30a and the second medium 30b may have the same color, and the first particles 31a and the second particles 31b may have the same color.

  In this case, one pixel is constituted by the adjacent first medium 30a and second medium 30b, and then the voltage applied to the XA electrode 12a1 and the XB electrode 12a2 by the control unit 70 included in the main body 20 of the display device 1. By controlling the application of each independently, it is possible to display an image with high gradation display.

  Further, in the above embodiment, the first particles 31a or the second particles 31b dispersed in the first medium 30a or the second medium 30b are each a single color particle that is positively or negatively charged. Although configured, it may be configured of positively charged particles and negatively charged particles having a color different from the color of the positively charged particles.

  In the above embodiment, the first medium 30a and the second medium 30b are arranged in a stripe pattern, but the first medium 30a and the second medium 30b are arranged in a checkered pattern or a honeycomb pattern. It may be configured to do. In this case, the first surface treatment layer 19a and the second surface treatment layer 19b are configured in a checkered pattern or a honeycomb, so that the first medium 30a and the second medium 30b are formed in a checkered pattern or a honeycomb. It can be easily arranged in a desired shape.

  In the above embodiment, the X electrode 12a and the Y electrode 13a are provided on the opposing surfaces of the first substrate 12 and the second substrate 13, but the X electrode 12a and Y electrode are provided on the image display medium 10. You may comprise so that the electrode 13a may not be provided. In this case, a pair of electrodes corresponding to the X electrode 12a and the Y electrode 13a is provided on the main body 20 side. In the display device 1, the pair of electrodes provided on the main body 20 side is provided with the X electrode 12a and the Y electrode 13a. What is necessary is just to comprise so that an image may be displayed by inserting | pinching the image display medium 10 which is not.

  In the above embodiment, the first medium 30a is mainly water or an aqueous solution, and the second medium 30b is mainly described as a solvent insoluble in water or a solution containing the solvent. However, phase separation is performed at least at room temperature. As long as it is a thing, both the 1st medium 30a and the 2nd medium 30b may be a solvent insoluble in water, or a solution containing the solvent.

  In the above embodiment, the image display medium 10 has been described as being separable from the main body 20 of the display device 1. However, the image display medium 10 is configured integrally with the main body 20 and the display device 1. It may be.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure explaining the image display medium of this invention, (a) is a perspective view of the whole display apparatus which displays an image on an image display medium, (b) shows the structure of an image display medium roughly. It is a disassembled perspective view. It is typical sectional drawing of an image display medium. (A)-(e) is a figure explaining the 1st example of a surface treatment process. (A)-(e) is a figure explaining the 2nd example of a surface treatment process. It is a figure which shows typically preparation of the electrophoretic medium containing a charged particle. It is a figure explaining the process until the electrophoresis medium containing a charged particle is arrange | positioned between the board | substrates of an image display medium. It is a block diagram which shows the electric constitution of the display apparatus which is an apparatus which displays an image on an image display medium.

Explanation of symbols

10 Image display medium 12 First substrate (substrate)
12a X electrode (electrode)
12a1 XA electrode (electrode)
12a2 XA electrode (electrode)
13 Second substrate (substrate)
13a Y electrode (electrode)
18 Protective film 19a First surface treatment layer (first surface treatment part)
19b 2nd surface treatment layer (2nd surface treatment part)
30 Electrophoretic medium 30a First medium 30b Second medium 31 Charged particle 31a First particle (charged particle)
31b Second particle (charged particle)
78 X pulse voltage control circuit (electric field control means)

Claims (21)

A pair of substrates disposed substantially in parallel and spaced apart, a charged particle, and an electrophoretic medium containing the charged particle and disposed between the pair of substrates, In the image display medium capable of switching the display state by moving the charged particles contained in the electrophoretic medium by an electric field generated between the substrates,
The electrophoretic medium includes a first medium exhibiting a first color and a second medium capable of phase separation at least at room temperature with respect to the first medium and exhibiting a second color. An image display medium, wherein the medium and the first medium form a predetermined pattern in a state of being phase-separated from each other. A first surface treatment unit having a higher affinity for the first medium than the second medium;
A second surface treatment unit having a higher affinity for the second medium than the first medium,
The second surface treatment unit and the first surface treatment unit are respectively arranged on the surface of at least one of the pair of substrates in contact with the electrophoretic medium so as to correspond to the predetermined pattern. The image display medium according to claim 1.   The said 1st medium and the said 2nd medium are either the solution which contains either the solvent insoluble with respect to the other, respectively, or the solvent insoluble with respect to the other, respectively. Image display medium.   4. The image display medium according to claim 3, wherein one of the first medium and the second medium is water or an aqueous solution, and the other is a water-insoluble solvent or a solution containing the solvent.   The image display medium according to claim 4, wherein the water is distilled water or deionized water.   The water-insoluble solvent is an aromatic hydrocarbon solvent, aliphatic hydrocarbon solvent, halogenated hydrocarbon solvent, silicone oil, or high-purity petroleum alone, or a mixture containing two or more of these. 6. The image display medium according to claim 4, wherein the image display medium is provided.   The charged particles have a first particle having a surface that is more compatible with the first medium than the second medium, and a surface that is more compatible with the second medium than the first medium. The image display medium according to any one of claims 1 to 6, further comprising: second particles having:   The image display medium according to claim 7, wherein the first particles and the second particles are colored in different colors.   The image display medium according to claim 1, wherein the first medium and the second medium are colored in different colors. A pair of electrodes are respectively provided on surfaces of the pair of substrates facing each other,
The image display medium according to claim 1, wherein a liquid-resistant protective film is provided on a surface of each electrode of the pair of electrodes.   The image display medium according to claim 10, wherein the protective film is a protective film containing a fluorine-containing compound.   The image display medium according to claim 1, wherein each of the pair of substrates has flexibility.   The image display medium according to claim 1, further comprising a spacer for holding a distance between the pair of substrates at a predetermined distance or more.   One of the pair of electrodes is composed of first electrodes and second electrodes that are alternately arranged while being separated from each other, and the first medium is disposed at a position corresponding to the position of the first electrode, The image display according to claim 10, wherein the predetermined pattern is formed by arranging the second medium at a position corresponding to the position of the second electrode. Medium. A first surface treatment unit having a higher affinity for the first medium than the second medium;
A second surface treatment unit having a higher affinity for the second medium than the first medium,
15. The image display according to claim 14, wherein the first surface treatment unit is disposed on a surface of the first electrode, and the second surface treatment unit is disposed on a surface of the second electrode. Medium. The image display medium according to claim 14 or 15,
The electric field generated between the first electrode and the electrode facing the first electrode and the electric field generated between the second electrode and the electrode facing the second electrode are independently controlled. An electrophoretic display device comprising: an electric field control means for performing the operation.   The electric field control means applies voltages having different drive waveforms to the first electrode or the second electrode, thereby controlling the electric fields independently. 16. The electrophoretic display device according to 16. A pair of substrates disposed substantially in parallel and spaced apart, a charged particle, and an electrophoretic medium containing the charged particle and disposed between the pair of substrates, In the method of manufacturing an image display medium capable of switching the display state by moving the charged particles contained in the electrophoretic medium by an electric field generated between the substrates,
The electrophoretic medium, which is a mixture of a first medium exhibiting a first color, and a second medium exhibiting a second color capable of phase separation at least at room temperature with respect to the first medium, the pair of substrates A medium disposing step of disposing on a surface of at least one of the substrates facing the other substrate;
A medium separating step of forming a predetermined pattern by the first medium and the second medium by causing the first medium and the second medium in the electrophoretic medium disposed in the medium disposing step to phase separate from each other. A method for manufacturing an image display medium, comprising: One of the pair of electrodes provided on the surfaces of the pair of substrates facing each other is composed of first electrodes and second electrodes that are alternately arranged while being separated from each other,
On the surface of the second electrode, a second surface treatment unit having a higher affinity for the second medium than the first medium is provided. On the other hand, on the surface of the first electrode, the second medium is more than the second medium. A surface treatment step of providing a first surface treatment unit having a higher affinity for the first medium,
In the medium separation step, when the first medium and the second medium are phase-separated, the first medium becomes a position corresponding to the position of the first electrode, while the second medium is the first medium. 19. The manufacturing method of an image display medium according to claim 18, wherein the electrophoretic solvent is selectively arranged so as to be a position corresponding to a position of two electrodes to form the predetermined pattern. Method.   Before the surface treatment of the first electrode and the second electrode in the surface treatment step, a liquid-resistant protective film is formed on each surface of the pair of electrodes by applying a liquid containing a fluorine-containing compound. 20. The method for manufacturing an image display medium according to claim 19, further comprising a protective film forming step. The charged particles include first particles having a greater affinity for the first medium than the second medium, and second particles having a greater affinity for the second medium than the first medium. 21. The method of manufacturing an image display medium according to claim 18, wherein the image display medium is included.

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