JP2007155879A - Particle moving type display device and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a particle moving type display device secured more firmly than a partition wall indicated in patent documents 2 by adhesion strength of the partition wall and difficult to be exfoliated from an electrode member by the partition wall even when the partition wall thinner than the width of the electrode member is formed. <P>SOLUTION: The particle moving type display device arranges a grid frame-like common electrode 6 surrounding a display electrode 5 on the surface of a rear substrate 1 arranging the display electrode 5. The device forms a connection layer 9 of the same contour as the common electrode 6 on the common electrode 6, and forms the partition wall 7 of a thickness narrower than the width of the common electrode 6 on the connection layer 9. The device arranges a resistant layer 7 integrally covering an erection face of the partition wall 8; the surface of the connection layer 9 protruded from the partition wall 7 and the surface of the display electrode 5. For the connection layer 9, a material having an adhesion higher than the common electrode 6 to the partition wall 8, transparency and conductivity is selected. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a particle movement display device that displays charged cells by moving charged particles in a moving space partitioned by a partition member, and more specifically, is formed on a substrate member so as to overlap with a thin film electrode member. The present invention relates to a device of a manufacturing method for increasing the strength of a partition member.

  2. Description of the Related Art In recent years, research and development of an image display device (particle moving display device) that performs display for each display cell by moving colored charged particles in a moving space partitioned by a partition member has been active. An example of the particle movement type display device is an electrophoretic display device in which a charged liquid is dispersed in a moving space, and charged electrophoretic particles are moved by applying a voltage to a pair of electrode surfaces arranged in the moving space. . The electrophoretic display device has a high display contrast, a wide viewing angle, a memory property for display, and no need for a backlight or a polarizing plate, as compared with a general liquid crystal display device as a conventional image display device. It has various features.

  Patent Document 1 discloses an electrophoretic display device in which a display electrode is arranged in the center of a pixel of a substrate member, and a partition electrode is disposed on a rising surface of a partition surrounding the display electrode (see FIG. 5). Here, the white display electrode is covered with black charged particles to perform black display of the pixel, and the charged particles are collected on the rising surface of the partition wall so that the display electrode can be seen, thereby displaying the pixel in white.

  In Patent Document 2, an insulating layer is disposed so as to cover a display electrode disposed on a substrate member, and a lattice frame-shaped thin film electrode member is disposed on the insulating layer so as to surround the display electrode. A partition wall having a thickness equal to the width of the thin film electrode member is disposed on the thin film electrode member. This is because the metal thin film material layer of the thin film electrode member is acid-etched using the resin partition as a mask, thereby forming the thin film electrode member into a lattice frame shape.

Japanese Patent No. 3421494 JP 2005-292789 A

  In the electrophoretic display device disclosed in Patent Document 1, switching elements and wiring patterns for driving pixels can be disposed under the display electrodes of the substrate member. In some cases, a driver circuit such as a driver is arranged by connecting to a wiring pattern on the substrate member, or an electrode array for wiring extraction is provided at a corner of the substrate member. In these cases, the partition wall electrode must also be connected to the wiring pattern on the substrate member.

  In the electrophoretic display device disclosed in Patent Document 2, a lattice frame-shaped thin film electrode member is disposed to connect the partition wall electrode to the wiring pattern on the substrate member. By forming a partition wall made of a conductive material on a lattice frame-shaped thin film electrode member formed on the substrate member, the rising surface of the partition wall becomes a partition wall electrode connected to the thin film electrode member.

  However, as shown in Patent Document 2, when the partition is formed of a photosensitive resin material, the adhesion strength between the base of the partition and the thin film electrode member may be insufficient. In addition to the fact that the contact width between the partition wall and the thin film electrode member is as thin as several μm and originally has a low adhesion strength, the resin and the metal thin film have different coefficients of thermal expansion, so that stress is likely to occur on the joint surface. Further, when the partition wall patterned in a lattice frame shape is subjected to heat treatment, the partition wall may shrink in the thickness direction, and the bonding surface may be peeled off.

  In addition, when a partition wall electrode is formed by patterning an insulating resin material to form a partition wall and covering the surface of the partition wall with a conductive material, electrical connection between the thin film electrode member on the substrate member and the partition wall electrode layer It is necessary to make sure. Therefore, the partition wall is formed to be thinner than the width of the thin film electrode member so that the thin film electrode member protrudes from the base of the partition wall (see FIG. 1), and the surface of the protruding thin film electrode member and the rising surface of the partition wall are integrally conductive. It was proposed to coat with material.

  However, in this case, the bonding area is reduced, and the corner portion where the partition wall and the thin film electrode member are connected becomes a stress concentration point, which is much weaker than the thick partition shown in Patent Document 2 and is easily peeled off. Become.

  In the present invention, the adhesion between the partition wall and the thin film electrode member is ensured more firmly than the partition wall shown in Patent Document 2, and even if the partition wall is formed thinner than the width of the thin film electrode member, the partition wall peels off from the thin film electrode member. An object of the present invention is to provide a particle movement type display device that is difficult.

  The particle movement type display device of the present invention includes a thin film electrode member disposed on the surface of the substrate member, and a partition member disposed on the substrate member in a positional relationship at least partially overlapping with the thin film electrode member. Then, a conductive connection layer having higher adhesion than the thin film electrode member is disposed between the thin film electrode member and the partition member.

  In the particle movement type display device of the present invention, since the connection layer having high adhesion is disposed between the thin film electrode member and the partition, the thin film electrode member and the partition are compared with the case where the partition is directly connected to the thin film electrode member. Bonding strength with is increased. Since the connection layer has conductivity, a conductive material layer (covering layer, partition electrode layer) is formed between the thin film electrode member and the partition member, or on the surface of the thin film electrode member and the partition member. Does not hinder the electrical connection between the resistor layer and the like.

  Hereinafter, electrophoretic display devices 100 and 200 according to embodiments of the present invention will be described in detail with reference to the drawings. The electrophoretic display device 100 is a monochrome image display device that displays white and black in two gradations in a display cell for each pixel using a whitened reflecting surface and black charged particles. However, it may be a monochrome image display device that displays an intermediate gradation (gray scale), or a color image may be displayed using charged particles of another color. Further, R, G, and B color filters may be arranged in three adjacent display cells, respectively, so that a full color display of one pixel is performed.

  Although the electrophoretic display device 100 is a reflective type that does not have a backlight, the present invention may be implemented as a transmissive display or a transflective device in which a backlight is provided on the back side of the rear substrate 1.

  The electrophoretic display device 100 may be implemented as an active matrix type in which switching elements formed for each pixel are dynamically controlled by a large number of write signal lines and a large number of scanning signal lines arranged in a lattice pattern. However, the present invention may employ a pixel driving method other than the active matrix type.

  The electrophoretic display device 100 is an image display device in which an infinite number of display cells 20 are arranged in a grid pattern on the rear substrate 1. In FIG. 1, two display cells 20 are representatively illustrated. Further, the general structure of the electrophoretic display device disclosed in Patent Documents 1 and 2, the general manufacturing method, the display method of the intermediate gradation, the driving method of the display cell, and the like are different from the gist of the present invention. Therefore, in order to avoid complications, some illustrations are omitted and detailed description is also omitted.

  The particle movement type display device of the present invention can be implemented both when a charged particle is interposed between a pair of substrates and when a charged particle dispersed in an insulating liquid is interposed. However, since the essence of these embodiments is the same, a typical embodiment of the latter electrophoretic display device will be described below.

<First Embodiment>
FIG. 1 is a side sectional view illustrating the configuration of the electrophoretic display device according to the first embodiment, FIG. 2 is a plan view illustrating the configuration and arrangement of pixels of the electrophoretic display device, and FIG. 3 is a transflective type. It is a rough explanatory drawing of the structure of the display electrode vicinity.

  As shown in FIG. 1, the electrophoretic display device 100 according to the first embodiment includes a spacer between a rear substrate 1 located on the rear side viewed from the observation side and a transparent front substrate 2 located on the observation side. The partition wall 8 is arranged. A moving space 21 of the display cell 20 formed by partitioning the gap between the rear substrate 1 and the front substrate 2 with the partition wall 8 is filled with an insulating dispersion liquid 3 in which black charged particles 4 are dispersed.

  As shown in FIG. 2, the partition wall 8 divides the moving spaces 21 of a large number of display cells 20 constituting the electrophoretic display device 100 into a lattice shape and separates them from each other, and the partition walls 8 surrounding the moving space 21 stand up. The resistance layer 7 formed on the surface functions as a partition wall electrode. Thus, by partitioning the pixels a and b one by one by the partition wall 8, the movement of the charged particles 4 that are black particles that can move in the moving space 21 of the display cell 20 to the other display cells 20 can be suppressed. . Then, the number of charged particles 4 of the pixels a and b can be made substantially equal, and high-quality image display can be achieved.

  In the electrophoretic display device 100 of the first embodiment, the partition wall 8 is arranged so as to partition the pixels a and b one by one. However, the partition wall 8 is arranged so that one pixel is further partitioned into a plurality of pixels, or a plurality of pixels are collectively partitioned, that is, a plurality of pixels are included between adjacent partition walls 8. May be.

  As shown in FIG. 1, both the pixels a and b occupy the bottom surface of the moving space 21, the planar display electrode 5 is disposed on the rear substrate 1, surrounds the display electrode 5, and the rear substrate 1 has a lattice. A frame-shaped common electrode 6 is arranged. A connection layer 9 having the same contour is stacked on the common electrode 6, and a partition wall 8 having a thickness smaller than the width of the common electrode 6 is disposed on the connection layer 9.

  The connection layer 9 is conductive, transparent, and formed of a material having higher adhesion to the partition wall 8 than the common electrode 6, and can be patterned in the same process as the common electrode 6.

  The resistance layer 7 is disposed so as to cover the bottom surface of the moving space 21, the surface of the partition wall 8, the surface of the connection layer 9 protruding from the partition wall 8, and the stepped side surfaces of the common electrode 6 and the connection layer 9. The interface of the moving space 21 except 2 is integrally covered.

  The resistance layer 7 forms an electrode surface connected to the common electrode 6 on the rising surface of the partition wall 8 surrounding the display electrode 5, and functions as a partition electrode that collects the charged particles 4. In addition, the resistance layer 7 prevents the dispersion liquid 3 from being ionized and charged, and improves the staying property of the charged particles 4 on the electrode surface while keeping the charged state of the charged particles 4 stable, thereby improving the memory performance of the pixel display. The effect to raise is also realized.

  By the way, the display electrode 5 has a diffuse reflection function with respect to incident light from the front substrate 2 side. In the following, for the sake of simplicity, the expression “reflection at the electrode” is used, but this expression uses the surface reflection characteristics of the target electrode itself (the electrode surface is formed into a desired shape). For example, an underlayer such as an uneven layer may be used in combination. Further, it also includes the meaning of using, for example, volume phase holograms or diffusion characteristics of a light diffusing substance formed on the mirror surface electrode, and further providing a transparent electrode on these structures.

  In the electrophoretic display device 100 according to the first embodiment configured as described above, the charged particles 4 stand up between the display electrode 5 and the partition wall 8 according to the voltage polarity applied between the display electrode 5 and the common electrode 6. Move between planes.

  Then, as shown in the pixel a in FIG. 2, the black charged particles 4 are collected on the display electrode 5 to cover the surface of the display electrode 5, so that the display cell 20 observed from the front substrate 2 side becomes a black display. . On the other hand, as shown in the pixel b in FIG. 2, the black charged particles 4 are collected on the rising surface of the partition wall 8 to expose the surface of the display electrode 5, so that the display cell 20 observed from the front substrate 2 side displays white. It becomes.

  In addition, the display electrode 5 is partially covered with the charged particles 4 by adjusting the voltage and the application time for attracting the charged particles 4 to the display electrode 5 side from the state where the charged particles 4 are collected on the rising surface of the partition wall 8. Intermediate gradation (grayscale) can also be displayed.

  As shown in FIG. 1, the pixel b is in a state where the charged particles 4 are accumulated on the partition wall 8 side, in other words, the charged particles 4 are accumulated on the partition electrode side. In this state, incident light from the front substrate 2 side that is incident on the display cell 20 is reflected by the display electrode 5, and the pixel b is brightly displayed. Further, the pixel a is in a state in which the charged particles 4 are moved so as to diffuse along the display electrode 5, and in this state, incident light from the front substrate 2 side that is incident on the display cell 20 is generally applied to the charged particles 4. As a result, the pixel a is darkly displayed.

<Manufacturing method and materials used>
Next, the rear substrate 1, the front substrate 2, the dispersion liquid 3, the charged particles 4, the display electrode 5, the common electrode 6, the resistance layer 7, the partition 8, the material of the connection layer 9, the manufacturing method of the electrophoretic display device 100, etc. explain.

  As a material for the rear substrate 1 and the front substrate 2, glass, quartz, or the like can be used in addition to a plastic film such as polyethylene terephthalate (PET), polycarbonate (PC), or polyethersulfone (PES). Since the electrophoretic display device 100 is a reflection type, it is necessary to use a transparent material for the front substrate 2 and the like disposed on the viewer side. However, the rear substrate 1 has an opaque material such as a metal material or polyimide ( Colored materials such as PI) may be used. A metal film such as stainless steel may be used, but when a metal material is used, the surface is appropriately coated with an insulating material.

  In order to drive the pixels, as in the case of a general liquid crystal display device, a grid-like wiring pattern that is three-dimensionally crossed can be arranged on the rear substrate 1, and a switching element can be arranged at each intersection of the wiring patterns. A contact hole is formed on the switching element by laminating an adhesive layer, an insulating layer, a sealing layer, and the like as necessary.

  As the material of the dispersion liquid 3, it is desirable to use an insulating nonpolar solvent such as isoparaffin, silicone oil, xylene, toluene, and the like that is transparent. This is because a bright pixel display can be realized by reducing the loss of illumination light in the white display.

  As the material of the charged particles 4, a material that is colored and exhibits good positive or negative charge characteristics in the dispersion liquid 3, for example, various inorganic pigments, organic pigments, carbon black, or the like are contained. Resin can be used. The particle size of the charged particles 4 can be generally about 0.01 μm to 10 μm, but preferably about 0.5 μm to 6 μm from the viewpoint of dispersibility and contrast.

  Moreover, it is preferable to add a charge control agent for controlling and stabilizing the charging of the charged particles 4 to the dispersion liquid 3 and the charged particles 4 described above. As such a charge control agent, a metal complex salt of a monoazo dye, salicylic acid, an organic quaternary ammonium salt, a nigrosine compound, or the like can be used.

  Furthermore, it is preferable to add a dispersing agent for preventing aggregation of the charged particles 4 and maintaining the dispersed state in the dispersion liquid 3. As such a dispersant, a phosphate polyvalent metal salt such as calcium phosphate or magnesium phosphate, a carbonate such as calcium carbonate, other inorganic salts, inorganic oxides, or organic polymer materials can be used.

  The common electrode 6 is a conductive material that can be easily patterned in a lattice frame shape with the required accuracy, for example, a metal thin film such as titanium (Ti), aluminum (Al), copper (Cu), chromium (Cr), or carbon It is preferable to form it with silver paste or an organic conductive film. When the display cell is bordered to serve as a black matrix that blocks unnecessary reflected light, a black material is selected or the surface is colored black.

  The display electrode 5 is preferably formed of a highly light reflective material such as silver or Al. In order to prevent insulation between the display electrode 5 and the common electrode 6 and injection of charges from the display electrode 5 to the charged particles 4, exposed portions of the display electrode 5 and the common electrode 6 are not shown in an insulating layer or dielectric not shown. It may be coated with a layer.

  As a manufacturing method of the display electrode 5 having a diffuse reflection function, for example, a method for forming fine irregularities on glass and depositing a metal, or applying a photosensitive resin, and then performing exposure and wet development to produce irregularities. There are methods for depositing metal. Further, there are a method of forming a mixed layer of particles and resins having different refractive indexes on a metal layer, a method of producing a hologram by interference exposure, and the like. However, any method may be used as long as desired scattering characteristics and directivity can be obtained.

  In the case of a particle movement type display device, brightness and darkness are determined by the size of the development area of the charged particles visually recognized by an observer, so that the contrast is different from the liquid crystal display device in which brightness is determined by the polarization angle. Therefore, when designing the uneven shape of the display electrode 5, there is no limit to pay attention so that depolarization of reflected light does not occur.

  In addition, when a metal layer made of a material having specular reflection characteristics such as aluminum is formed on the uneven layer having an appropriate surface shape, the display electrode 5 is colored in particular white because it automatically becomes a white scattering surface. There is no need. On the surface (mirror surface) of the metal thin film layer having no irregularities, a light diffusion layer is formed by dispersing volume phase holograms and fine particles in a resin binder having a refractive index different from this, and diffusely reflected on the display electrode 5. A function may be added.

  In particular, a forward scattering layer such as an antiglare layer may be disposed on the front substrate 2 on the observation side in order to suppress the specular reflection component from the display electrode 5 from being visually metallic.

The material of the resistance layer 7 is a light transmissive material, and an organic film such as polysilane, polysiloxane, or polyacetylene, or a composite or copolymer thereof can be used. In addition, a carbon-containing film, an inorganic film such as indium-tin oxide (ITO), a semiconductor film such as silicon, or a conductive filler (filler) such as metal powder or carbon particles is used as an epoxy resin, polypropylene resin, or the like. A conductive resin film obtained by blending with can also be used. Furthermore, a laminated film of these films may be used as the interface member. In order to fulfill the above-described function as the interface layer, the volume resistivity is desirably 10 ⁶ Ωcm to 10 ¹² Ωcm, and the film thickness is desirably 1 nm to 200 nm. When an indium-tin oxide (ITO) thin film is used, it is formed with a thinner film thickness than the film thickness used as a normal transparent electrode. As the film thickness is reduced, the resistance value of the thin film increases and can be used as a practical resistance layer 7.

  As the material of the partition wall 8, the same material as the display substrate 1 may be used, or a photosensitive resin such as acrylic or resist may be used. The partition wall 8 is formed by, for example, a method in which a photosensitive resin layer is applied and then exposure and wet development are performed, or a method in which a separately manufactured mesh-shaped partition wall 8 is bonded (or transferred), or a printing method. Or the like can be used.

  As a material of the connection layer 9, the same material as that of the resistance layer 7 may be used as long as the common electrode 6 and the partition wall 8 can be in close contact with each other. As described above, the connection layer 9 is made of a material that is conductive, transparent, and has a higher adhesion to the partition wall 8 than the common electrode 6. Here, the reason why the connection layer 9 is made of a transparent material is to make the common electrode 6 black and transmit the color.

  Specifically, the common electrode 6 can be formed of a metal thin film such as titanium (Ti), aluminum (Al), copper (Cu), or chromium (Cr). As a black material that does not require additional coloring, a “laminated film of Cr and Cr oxide” that is a metal thin film such as Cr can be used. As the connection layer 9 laminated on the common electrode 6, an organic film such as polysilane, an inorganic film such as indium-tin oxide (ITO), indium-zinc oxide (IZO), or the like can be employed.

  As a method for forming the connection layer 9, a general photolithography technique can be used. For example, after forming an inorganic film, a photosensitive resin layer is applied, an unnecessary portion of the photosensitive resin layer is removed by exposure and development, and a portion of the inorganic film not covered by the photosensitive resin layer is removed by wet etching. Remove.

  When a material that can apply the same etching process as the common electrode 6 is selected as the material of the connection layer 9, the material layer of the common electrode 6 and the material layer of the connection layer 9 are continuously laminated on the entire surface of the rear substrate 1. A photolithography technique is applied to the laminated film. Thereby, the common electrode 6 and the connection layer 9 can be patterned into a lattice frame at the same time.

  In order to perform black and white or color display using the electrophoretic display device 100 having such a configuration, the charged particles 4 and other members need to be appropriately colored. For example, when performing monochrome display, the color of the display electrode 5 is white and the color of the charged particles 4 is black.

  The electrophoretic display device 100 according to the first embodiment is a reflective type in which the display electrode 5 is provided with a diffuse reflection function, but a transmissive or transflective embodiment similar to a conventional liquid crystal display is also possible. It is. In the case of the transmissive type, the rear substrate 1 is transparent, the display electrodes 5 are formed to be translucent, and a backlight including a light source, a light guide plate, a prism sheet, and the like is disposed behind the rear substrate 1.

  In the case of the semi-transmissive type, as shown in FIG. 3, the uneven layer 10 that realizes the diffusing function is made transparent, and the thickness of the metal layer 11 that realizes the reflecting function is made thin so as to be semi-transmissive. Then, adjustment is made so that at least part of the light from the backlight 31 passes through the metal layer 11 and proceeds from the moving space 21 to the front substrate 2. By adjusting the thickness of the metal layer 11, the ratio of reflection and transmission can be adjusted to a desired value. However, when the thickness of the metal layer 11 is reduced, the electrical conductivity is lowered, and the function as the display electrode 5 may be lowered. In such a case, a transparent electrode 11A may be separately provided on the metal layer 11 to compensate for the thickness of the display electrode 5. As a material constituting the transparent electrode 11A, a conventionally known material such as an inorganic oxide such as ITO or ZnO or an organic conductive material may be used. In FIG. 3, the transparent electrode 11 </ b> A is formed directly on the metal layer 11, but a layer (not shown) such as a planarization layer may be interposed between the transparent electrode 11 </ b> A.

<Prototype procedure>
The electrophoretic display device 100 of the first embodiment shown in FIGS. 1 and 2 was prototyped according to the following procedure. As shown in FIG. 1, a glass substrate having a thickness of 1.1 mm is used for the rear substrate 1 of the electrophoretic display device 100, and the size of one pixel (display cell 20) is 100 μm × 100 μm. The width of the partition wall 8 arranged at the boundary is 5 μm and the height is 18 μm. The display electrode 5 is disposed at the center of the bottom surface of the pixels a and b, and has a side of 90 μm and a thickness of 0.1 μm. The common electrode 6 is positioned between the partition wall 8 and the rear substrate 1, has a thickness of 0.1 μm, is arranged with a pixel border bordered in a lattice frame shape, and has a width of 5 μm.

  Next, a manufacturing method of the electrophoretic display device 100 of the first embodiment will be described. First, a photosensitive resin (trade name: OMR83-20Cp, manufactured by Tokyo Ohka Kogyo Co., Ltd.) for forming a fine uneven layer 10 (FIG. 3) is applied to the rear substrate 1 so as to have a thickness of 1.2 μm. Then, the convex part was pattern-formed by pattern exposure and wet development, and was cured by heat treatment at 120 ° C. for 30 minutes.

  Next, an aluminum film having a thickness of 150 nm is formed as a metal layer 11 (FIG. 3) on the entire surface of the rear substrate 1 on which the concavo-convex layer 10 is formed, and then the contour is patterned by photolithography and wet etching to form display electrodes. 5 was formed.

  Subsequently, a transparent photosensitive resin (acrylic resin) is applied on the rear substrate 1 on which the display electrode 5 is formed to eliminate the step, flatten the surface, perform exposure and wet development, and remove the unevenness in the central portion of the display electrode 5. The illustrated contact hole was formed. An insulating photosensitive resin that covers the surface of the display electrode 5 is patterned to form a contact hole in the center of the display electrode 5. Since the resistance layer 7 and the display electrode 5 are connected through this contact hole, the entire surface of the display electrode 5 and the resistance layer 7 do not contact each other, and a desired resistance value can be set between them.

  And the titanium used as the common electrode 6 was formed in the whole surface of the hardened resin layer, and the common electrode 6 was formed by patterning in a grid | lattice form using a photolithographic technique and dry etching.

  Next, an IZO film was formed on the entire surface, and patterned to the same contour as the common electrode 6 using a photolithography technique and dry etching to form a connection layer 9.

  Next, a photosensitive epoxy resin is applied to the entire surface of the rear substrate 1 formed up to the connection layer 9, mask exposure and wet development are performed to remove the photosensitive epoxy resin in the moving space 21, so that the partition wall 8 is good. Formed.

  Next, an ITO film was formed on the entire surface of the rear substrate 1 on which the partition walls 8 were well formed to form the resistance layer 7. The resistance layer 7 covering the rising surface of the partition wall 8 is continuously laminated on the surface of the connection layer 9 protruding from the base of the partition wall 8, and is electrically connected to the common electrode 6 through the conductive connection layer 9.

  The moving space 21 partitioned by the partition wall 8 on the rear substrate 1 was filled with the dispersion liquid 3 and the charged particles 4. Here, isoparaffin (trade name: Isopar, manufactured by Exxon) is used for the dispersion liquid 3, and a polystyrene-polymethyl methacrylate copolymer resin containing carbon black having a particle diameter of about 1 to 2 μm is used for the charged particles 4. use. The isoparaffin contains succinimide (trade name: OLOA 1200, manufactured by Chevron) for charge control.

  On the other hand, an ultraviolet curable resin as a sealing (adhesion) layer is applied to the front substrate 2. The front substrate 2 is made of polyethylene terephthalate having a thickness of 25 μm, and the material of the ultraviolet curable resin is a mixture containing polyethylene glycol methacrylate as a main component.

  Then, the front substrate 2 is brought into intimate contact with the partition wall 8 filled with the dispersion liquid 3 and the charged particles 4, and ultraviolet rays are irradiated from the front substrate 2 side while pressing the curable resin layer so as to contact the dispersion liquid 3. The front substrate 2 is bonded to the partition wall 8 by curing the ultraviolet curable resin layer. As a result, the insulating dispersion liquid 3 and the black charged particles 4 are included in a section (closed space) formed by the rear substrate 1, the front substrate 2, and the partition wall 8.

  Finally, a voltage application circuit (not shown) was connected to the electrophoretic display device 100 to obtain an image display device.

  Then, a driving voltage of +30 V was applied to the display electrode 5 of the prototype electrophoretic display device 100, and a driving voltage of 0 V was applied to the common electrode 6. Further, a drive voltage of −30 V was applied to the display electrode 5, and a drive voltage of 0 V was applied to the common electrode 6. In both cases, it was confirmed that the voltage application time was 100 ms, and the charged particles 4 moved to the negative polarity side without remaining between the display electrode 5 and the rising surface of the partition wall 8. Display was obtained.

<Electrophoretic display device of comparative example>
In the electrophoretic display device 100 shown in FIG. 1, an electrophoretic display device of a comparative example in which the conductive material of the connection layer 9 is replaced with an insulating material was prototyped. Except for the material of the connection layer 9 being an insulating photosensitive resin (acrylic resin), the materials / dimensions and manufacturing processes of the respective constituent members are the same as those in the first embodiment.

  Next, a drive voltage of +30 V was applied to the display electrode 5 of the electrophoretic display device of the comparative example manufactured as described above, and a drive voltage of 0 V was applied to the common electrode 6. Further, a drive voltage of −30 V was applied to the display electrode 5, and a drive voltage of 0 V was applied to the common electrode 6. In either case, the voltage application time is 100 ms, but the contact between the common electrode 6 and the resistance layer 7 on the surface of the partition wall 8 is unstable, and part of the charged particles 4 may not move.

  As is clear from the comparison with the electrophoretic display device of the comparative example, the electrophoretic display device 100 of the first embodiment forms the partition wall 8 on the common electrode 6 via the conductive connection layer 9, The connection strength / adhesion between the partition wall 8 and the common electrode 6 is improved. In addition, since the resistance layer 7 and the connection layer 9 are in contact with each other, the common electrode 6 and the resistance layer 7 are in electrical contact with each other as a result. Therefore, even when the resistance layer 7 having a high sheet resistance is adopted, the entire rising surface of the partition wall 8 functions as an electrode surface having a uniform potential, and the stable reproducibility of the charged particles 4 between the partition wall 8 and the display electrode 5 is achieved. High driving is possible.

  In addition, in the large number of display cells 20 in the electrophoretic display device 100, the relationship between the drive voltage condition and the distribution state of the charged particles 4 is uniformly reproduced, and as a result, display variations from pixel to pixel are reduced and high quality is achieved. An intermediate gradation image can be displayed. As a result, when the RGB color filter layer is arranged and the full color display of one pixel is performed with three display cells, the variation in color display is reduced, and high-quality color image display is also possible.

  In the above description, an electrophoretic display device has been described as an example of a particle movement type display device. However, the present invention is not limited to this, and can be widely applied to various display devices that form at least two bright and dark display states by moving particles and changing the reflection condition of incident light in the reflective layer. For example, it can also be used in a dry display device called a toner display in which charged particles are moved in a gas without using a dispersion liquid to generate contrast. The present invention can also be used in a fine particle dispersed display device that generates contrast by moving particles dispersed in a liquid crystal.

  In addition, a plurality of pixels having the configuration described so far may be regularly arranged in a two-dimensional manner, and for example, a display device may be configured in combination with a driving circuit such as a TFT. In that case, it may be necessary to electrically connect the source electrode or drain electrode of the TFT and the display electrode 5 of the display device of the present invention. In this case, a part of the reflective layer is penetrated as necessary. Connection may be made by forming conductive vias.

Second Embodiment
FIG. 4 is a side sectional view for explaining the configuration of the electrophoretic display device of the second embodiment. The electrophoretic display device 200 according to the second embodiment is the first except that the three primary color layers 48, 49, 50 are arranged in the adjacent three display cells 22, 23, 24 to perform full color display of one pixel 41. The configuration is the same as that of the electrophoretic display device 100 of the embodiment. Therefore, the same components as those in FIGS. 1 and 2 are denoted by the same reference numerals, and detailed description thereof is omitted.

When performing color display with an electrophoretic display device, the charged particles 4 shown in FIG. 2 are not only those of a desired color (primary colors), but the charged particles 4 are substantially black. Thus, the region where the display electrode 5 is disposed may be colored in a desired color. Here, as a method of coloring the region where the display electrode 5 is arranged,
A method of coloring the display electrode 5 itself,
A method of arranging a separate colored layer on the display electrode 5;
A method of selectively reflecting only light of a specific wavelength by using the display electrode 5 itself or a hologram diffuser formed thereon;
A method of coloring the light diffusion layer formed on the display electrode 5 when combining the mirror electrode and the light diffusion layer,
There is a method of arranging a conventionally known color filter on the front substrate 2 side.

  As shown in FIG. 4, in the electrophoretic display device 200, red, green, and blue display cells 22, 23, and 34 (sub-pixels 42, 43, and 44) are two-dimensionally arranged to form one pixel 41, The full color display of the pixel 41 is performed by the gradation balance of the three display cells 22, 23 and 34. The pixel 41 includes a sub-pixel 42 (display cell 22), a sub-pixel 43 (display cell 23), and a sub-pixel 44 (display cell 24). The moving space 21 of the adjacent sub-pixel has a resistance layer on the surface. 7 are separated from each other by partition walls 8 covered with 7.

  The sub-pixels 42, 43, 44 have display electrodes 45, 46, 47 having a diffuse reflection function corresponding to the display electrode 5 of FIG. 1, and are disposed on the display electrodes 45, 46, 47. Are provided with a translucent red colored layer 48, a green colored layer 49, and a blue colored layer 50, respectively.

  Similarly to the first embodiment, the common electrode 6 is disposed between the rear substrate 1 and the partition wall 8, and the conductive connection layer 9 is disposed between the partition wall 8 and the common electrode 6. A contact hole (not shown) that exposes the display electrodes 45, 46, 47 is formed in the center of the red colored layer 48, the green colored layer 49, and the blue colored layer 50. The resistance layer 7 is disposed so as to cover the surfaces of the red colored layer 48, the green colored layer 49, and the blue colored layer 50 and connect the display electrodes 45, 46, 47 and the respective common electrodes 6.

  Thus, for example, when black particles are used as the charged particles 4, if the charged particles 4 in the moving space 21 cover the display electrodes 45, 46, 47 of the sub-pixels 42, 43, 44, black is visually recognized as the pixels 41. Is done. On the other hand, when the charged particles 4 are accumulated on the rising surface (the common electrode 6 side) of the partition wall 8 of the sub-pixels 42, 43, 44, white is visually recognized as the pixel 41.

  Also, as shown in FIG. 4, the charged particles 4 are deposited on the display electrode 1 by the second subpixel 43 and the third subpixel 44, and the charged particles 4 are moved to the partition wall 8 side by the first subpixel 42. Then, red is visually recognized as the pixel 41. Similarly, various colors can be exhibited by additive color mixture of green, blue, red, green, and blue.

  As for the colors of the colored layers 48, 49, and 50, cyan, magenta, and yellow may be combined instead of red, green, and blue. Further, there is no particular limitation on the arrangement pattern of the sub-pixels having these colors, and it goes without saying that various arrangements conventionally known in the field can be used.

  In addition, by forming the colored layers 48, 49, 50 on the display electrodes 45, 46, 47, the distance from the display electrodes 45, 46, 47 to the charged particles 4 is increased, and the drive voltage is increased and the operation time is reduced. An increase can occur. In order to reduce such a problem, the transparent electrode layer 11 </ b> A may be separately formed on the colored layer 48 as the configuration of the display electrode 45, for example, as in the configuration of FIG. 3.

  Furthermore, the electrophoretic display device 200 according to the second embodiment may be of a reflective type in which a front scattering layer is further arranged on the front substrate 2 side as described in the first embodiment. Further, as shown in FIG. 3, the display electrode 5 (45, 46, 47) is made semi-transmissive, the rear substrate 1 is made of a substantially transparent material, and a backlight is disposed behind the rear substrate 1. Thus, a transflective color image display device may be configured.

<Electrophoretic display device of another comparative example>
FIG. 5 is a side sectional view for explaining the configuration and operation of an electrophoretic display device of a comparative example. In FIG. 5, (a) is black display and (b) is white display.

  As shown in FIG. 5A, in the electrophoretic display device 300 of the comparative example, the front substrate 102 and the rear substrate 101 on the observation side are disposed to face each other with a partition wall 106 therebetween. A planar display electrode 105 whose surface is colored white is disposed on the rear substrate 101. Since the partition 106 is formed of a conductive material, the partition 106 itself functions as a partition electrode common to a large number of pixels constituting the electrophoretic display device 300. The surfaces of the display electrode 105 and the partition wall 106 are covered with dielectric layers 107 and 108.

  A moving space 21 in which a gap between the front substrate 102 and the rear substrate 101 is partitioned by a partition wall 106 is filled with an insulating dispersion liquid 103 and a large number of charged particles 104 colored in black.

  In the electrophoretic display device 300 of the comparative example, when the partition 106 of the common electrode is set to the ground potential (0 V) and a positive or negative voltage is applied to the display electrode 105, the charged particles 104 are displayed as rising surfaces of the partition 106. The dispersion liquid 103 migrates with the surface of the electrode 105. The color of the surface of the display electrode 105 between the case where the charged particles 104 are collected on the surface of the display electrode 105 and arranged in a wide projected area, and the case where the charged particles 104 are accumulated in the narrow projected area of the rising surface of the partition wall 106. Various displays are made using the difference.

  By the way, in the electrophoretic display device 300 of the comparative example, when the frame-shaped common electrode 6 (FIG. 1) is disposed on the rear substrate 101 and the partition 106 is disposed on the common electrode 6, the partition 106 extends from the common electrode 6. It may peel off.

  On the other hand, in the electrophoretic display device 100 according to the first embodiment and the electrophoretic display device 200 according to the second embodiment, as described above, a transparent and conductive material is provided in the gap between the common electrode 6 and the partition wall 8. Since the connection layer 9 is disposed, the partition wall 8 and the common electrode 6 are firmly connected and hardly peeled off.

  Further, since the resistance layer 7 is in contact with the surface of the conductive connection layer 9, the electrical connection between the resistance layer 7 on the surface of the partition wall 8 and the common electrode 6 is reliable.

  Moreover, since the connection layer 9 is transparent, the black matrix effect by the black common electrode 6 is not disturbed.

<Correspondence with Invention>
The electrophoretic display device 100 of the first embodiment includes a common electrode 6 disposed on the surface of the rear substrate 1 and a partition wall 8 disposed on the rear substrate 1 in a positional relationship at least partially overlapping the common electrode 6. A conductive connection layer 9 having higher adhesion than the common electrode 6 with respect to the partition wall 8 is disposed between the common electrode 6 and the partition wall 8.

  Therefore, since the connection layer 9 is disposed between the common electrode 6 and the partition wall 8, the bonding strength between the common electrode 6 and the partition wall 8 is higher than when the partition wall 8 is directly connected to the common electrode 6. Since the connection layer 9 has conductivity, it is electrically connected between the common electrode 6 and the partition wall 8 and between the common electrode 6 and the resistance layer 7 formed on the surface of the partition wall 8. Does not disturb the connection.

  In the electrophoretic display device 100, the connection layer 9 is transparent. Therefore, the color of the common electrode 6 can be visually recognized from the front substrate 2 side.

  In the electrophoretic display device 100, the connection layer 9 is stacked with the same outline as the common electrode 6.

  In the electrophoretic display device 100, the connection layer 9 is disposed so as to protrude from the partition wall 8 on the rear substrate 1, and the resistance layer 7 is disposed so as to integrally cover the protruding portion of the connection layer 9 and the rising surface of the partition wall. Yes. Therefore, the resistance layer 7 on the rising surface of the partition wall 8 is reliably connected to the common electrode 6 through the connection layer 9 without any gap.

  In the electrophoretic display device 100, the planar display electrode 5 for each display cell 20 is disposed on the rear substrate 1, and the common electrode 6 has a frame-like outline surrounding the display electrode 5, and is based on the thickness of the partition wall 8. Is also wide. Therefore, it is possible to form a black matrix that borders the outline of the display cell 20 by the common electrode 6 and blocks unnecessary reflected light and transmitted light.

  In the electrophoretic display device 200 according to the second embodiment, one pixel 41 includes a plurality of display cells 22, 23, and 24. Further, different primary color layers 48, 49, and 50 are arranged on the display electrodes 45, 46, and 47 of the plurality of display cells 22, 23, and 24, and the resistance layer 7 is arranged to cover the colored layers 48, 49, and 50. Has been.

  In the electrophoretic display device 100, the display electrode 5 also serves as a reflective surface to which diffuse reflectivity is imparted.

  In the electrophoretic display device 100, a partition wall 8 is disposed around the display electrode 5 disposed on the rear substrate 1. Then, the common electrode 6 and the conductive connection layer 9 having higher adhesion to the partition wall 8 than the common electrode 6 are provided on the rear substrate 1 with a frame-like outline surrounding the display electrode 5. After the structure is formed, the partition wall 8 is formed on the connection layer 9 in the laminated structure.

  In the electrophoretic display device 100, the partition wall 8 having a thickness narrower than the width of the connection layer 9 is formed substantially on the center line of the connection layer 9, the surface of the connection layer 9 that protrudes from the partition wall 8, and the rising of the partition wall 8. The resistance layer 7 is formed so as to cover the surface integrally.

  In addition, after laminating the material layer of the common electrode 6 and the material layer of the connection layer 9 on the rear substrate 1, a frame-like shape is formed on both the common electrode 6 and the connection layer 9 by a common photolithography process and an etching process. A contour may be formed.

It is a sectional side view explaining the structure of the electrophoretic display device of 1st Embodiment. It is a top view explaining the structure and arrangement | positioning of a pixel of an electrophoretic display device. It is a rough explanatory drawing of the structure of the display electrode vicinity at the time of setting it as a transflective type. It is a sectional side view explaining the structure of the electrophoretic display device of 2nd Embodiment. It is a sectional side view explaining the structure and operation | movement of an electrophoretic display apparatus of a comparative example.

Explanation of symbols

1 Substrate member (rear substrate)
2 Front substrate 3 Dispersed liquid 4 Charged particles 5, 45, 46, 47 Display electrode 6 Thin film electrode member (common electrode)
7 Conductive surface coating layer (resistance layer)
8 Bulkhead member (bulk)
9 Connection layer 20, 22, 23, 24 Display cell 21 Moving space 42, 43, 44 Subpixel 48, 49, 50 Colored layer

Claims (10)

A thin film electrode member disposed on the surface of the substrate member;
In a particle movement type display device comprising: a partition member disposed on the substrate member in a positional relationship at least partially overlapping with the thin film electrode member,
A particle transfer type display device, wherein a conductive connection layer having higher adhesion to the partition wall member than the thin film electrode member is disposed between the thin film electrode member and the partition wall member.   The particle movement type display device according to claim 1, wherein the connection layer is transparent.   3. The particle movement type display device according to claim 1, wherein the connection layer is laminated with the same outline as the thin film electrode member.   The connection layer is disposed so as to protrude from the partition member on the substrate member, and a conductive surface coating layer is disposed so as to integrally cover the protruding portion of the connection layer and the rising surface of the partition. The particle movement type display apparatus of Claim 3 characterized by the above-mentioned. A planar display electrode for each display cell is disposed on the substrate member,
5. The particle movement type display device according to claim 4, wherein the thin film electrode member has a frame-like outline surrounding the display electrode and is wider than the thickness of the partition wall member.   One pixel is composed of a plurality of the display cells, a colored layer of a different primary color is disposed on each of the display electrodes of the plurality of display cells, and the surface coating layer is disposed to cover the colored layer. The particle movement type display device according to claim 5.   7. The particle movement type display device according to claim 5, wherein the display electrode also serves as a reflection surface provided with diffuse reflection. In the manufacturing method of the particle movement type display device in which the partition wall is arranged surrounding the display electrode arranged on the substrate member,
A laminated structure of a thin film electrode member and a conductive connection layer having a higher adhesion to the partition wall than the thin film electrode member is formed on the substrate member with a frame-like outline surrounding the display electrode. And
A method for manufacturing a particle movement type display device, wherein the partition is formed on the connection layer in the laminated structure. On the center line of the width of the connection layer, a partition wall having a thickness narrower than the width is formed,
9. The method of manufacturing a particle movement type display device according to claim 8, wherein a conductive surface coating layer is formed by integrally covering the surface of the connection layer protruding from the partition wall and the rising surface of the partition wall. . After laminating the material layer of the thin film electrode member and the material layer of the connection layer on the substrate member, the frame shape is formed on both the thin film electrode member and the connection layer by a common photolithography process and etching process. The method of manufacturing a particle movement type display device according to claim 9, wherein the outline is formed.

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