JP2005345570A - Particle transfer type display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a particle transfer type display device with which a bright display with proper visibility is obtained. <P>SOLUTION: In the particle transfer type display device 100, absorption of scattered light is suppressed, by disposing a scattering layer 108A with a high scattering property on a center part of a pixel and a scattering layer 108B with a scattering property lower than that of the scattering layer 108A on a peripheral part thereof in the vicinity of a partition wall 103 on a first substrate 101. Consequently, reflectance as a pixel is enhanced, and a bright display with proper visibility is obtained. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a particle movement type display device that performs display by moving particles, and more particularly to a reflection type device that performs display by reflecting incident light.

  2. Description of the Related Art Conventionally, there are display devices such as an electrophoretic display device and a toner display that place a movable chargeable particle between a pair of opposing substrates and perform display based on the movement of these particles by applying a voltage. .

  These display devices are, for example, reflective display devices that do not display by emitting light such as a backlight of a liquid crystal display or a fluorescent material of a plasma display, but display by reflecting light incident from the display surface. is there. In order to improve the visibility of such a reflective display device, it is desirable that the reflectance of pixels to be displayed be improved.

  Therefore, in the conventional reflective liquid crystal display element, the reflective layer is provided on the rear side substrate, and the scattering layer is provided on the front side substrate, whereby the reflectance of the incident light is prevented while preventing the interference color from being generated in the reflected light. What is improved has been proposed (see Patent Document 1).

JP-A-8-338993

  However, in the conventional reflective liquid crystal display device including the reflective layer on the rear substrate and the scattering layer on the front substrate, the scattering property of the scattering layer is uniform, so that it does not reach the reflective layer after being scattered. There is a problem in that scattered light that is absorbed along the way tends to be generated, and the reflectance decreases.

  Accordingly, an object of the present invention is to provide a bright particle display type particle moving display device by increasing the reflectance by reducing the amount of scattered light absorbed.

  The present invention provides a first substrate and a second substrate disposed at positions facing each other with a predetermined gap, a partition wall that partitions the gap between the first substrate and the second substrate, and the first substrate A plurality of particles enclosed in a gap surrounded by the substrate, the second substrate, and the partition; a scattering layer disposed on the first substrate; and facing the second substrate In the particle movement type display device having a plurality of pixels formed by a reflective layer arranged between the first substrate and a plurality of electrodes arranged so as to be close to the gap, The scattering layer has a distribution with different scattering properties.

  Preferably, the scattering layer has different scattering properties in the pixel depending on a distance from the partition that forms a boundary of the pixel toward a central portion of the pixel.

  Preferably, the scattering layer has a different scattering property in the pixel depending on a distance from the accumulation portion toward the central portion of the pixel when the plurality of particles are accumulated in a peripheral portion of the pixel. It is what.

  Preferably, the scattering layer is characterized in that in the pixel, the scattering property is increased in accordance with a distance from the partition wall forming the boundary of the pixel toward a central portion of the pixel.

  Preferably, the scattering layer is characterized in that in the pixel, the scattering property is increased according to a distance from the integrated portion toward the central portion of the pixel.

  Preferably, the haze value of the scattering layer is increased according to the distance from the partition toward the center of the pixel.

  Preferably, the haze value of the scattering layer is increased according to the distance from the integrated portion toward the pixel central portion.

  According to the particle movement type display device according to the present invention, the first substrate and the second substrate are disposed at positions facing each other with a predetermined gap, and the gap is partitioned by a partition wall to enclose a plurality of particles. In a particle movement type display device that performs display by moving a plurality of particles based on applying a voltage to a plurality of electrodes, the scattering layer on the first substrate has a regular distribution with different scattering properties. Therefore, a bright and highly visible display screen can be obtained.

<First Embodiment>
Hereinafter, a particle movement type display apparatus according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view of two adjacent pixels of the particle movement type display device according to the first embodiment, and FIG. 2 is an upper surface of two adjacent pixels of the particle movement type display device according to the first embodiment. FIG.

  First, as shown in FIGS. 1 and 2, the particle movement display device 100 includes a first substrate 101, a second substrate 102, a partition wall 103, an insulating liquid 104, charged electrophoretic particles 105, and a first substrate. The electrode 106, the second electrode 107, and the scattering layers 108A and 108B are included.

  A particle movement type display device 100 according to the present invention is used by connecting to an information terminal device such as an electronic book or a personal digital assistant (PDA), a personal computer (PC), or the like. This is a display device that displays image data, character data, and the like transmitted from the device. As for the driving method at the time of display, like a liquid crystal display element or the like, for example, a driving circuit that performs simple matrix driving, active matrix driving, or the like is used, and each pixel is switched on and off by a voltage signal.

  Next, the first substrate 101 and the second substrate 102 which are the substrates of the particle movement type display device 100 are arranged at opposing positions with a predetermined gap therebetween, and these gaps are further partitioned by the partition wall 103. Pixels a and b are formed at the positions. For the first substrate 101 and the second substrate 102, glass, quartz, or the like is used in addition to a plastic film such as polyethylene terephthalate (PET), polycarbonate (PC), or polyethersulfone (PES). The first substrate 101 needs to use a transparent material having optical transparency, but the second substrate 102 may be colored with polyimide (PI) or the like.

  The partition 103 is made of the same material as the first substrate 101 and the second substrate 102 or a photosensitive resin such as acrylic. The partition wall 103 is formed by a method such as a method of performing exposure and wet development after applying a photosensitive resin layer, a method of bonding a separately created partition wall, a method of forming by a printing method, or the like. Further, the partition wall 103 and the first substrate 101 may be formed by integral molding.

  A space partitioned by the first substrate 101, the second substrate 102, and the partition wall 103 is filled with the insulating liquid 104 in which the charged electrophoretic particles 105 are dispersed. As this insulating liquid 104, a transparent nonpolar solvent such as isoparaffin, silicone oil, xylene, and toluene is used. The charged electrophoretic particles 105 are made of a colored material exhibiting positive or negative charging characteristics in the insulating liquid 104, and are inorganic pigments, organic pigments, carbon black, or resins containing them. Etc. are used.

  Note that a charge control agent for controlling and stabilizing the charging of the charged electrophoretic particles 105 may be added to the insulating liquid 104 and the charged electrophoretic particles 105 described above. As such charge control agents, metal complexes of monoazo dyes, salicylic acid, organic quaternary ammonium salts, nigrosine compounds, and the like are used. Further, the particle size of the charged electrophoretic particles 105 can be generally about 0.01 μm to 50 μm, preferably about 0.1 μm to 10 μm.

  In addition, a dispersing agent for preventing aggregation of the charged electrophoretic particles 105 and maintaining a dispersed state may be added to the insulating liquid 104. As such a dispersant, polyvalent metal phosphates such as calcium phosphate and magnesium phosphate, carbonates such as calcium carbonate, other inorganic salts, inorganic oxides, or organic polymer materials are used.

  On the other hand, the first electrode 106 (reflection layer) is disposed on the upper surface of the second substrate 102 at a position close to the insulating liquid 104. In addition, the second electrode 107 is disposed below the partition wall 103 and in a position close to the second substrate 102 and the insulating liquid 104. The scattering layers 108 </ b> A and 108 </ b> B have functions as the first substrate 101, but are distributed with different scattering characteristics so as to form layers.

  The first electrode 106 is formed of a material having high light reflectivity such as silver (Ag) or aluminum (Al), for example, and reflects the light incident from the scattering layers 108A and 108B. A reflective layer having a property, or at least one function thereof. The second electrode 107 is formed of a conductive material that can be patterned, and is formed of a metal such as titanium (Ti), Al, or copper (Cu), carbon, silver paste, or an organic conductive film. Note that an insulating layer may be formed on the surfaces of the first electrode 106 and the second electrode 107 so as to prevent the movement of charges from the first electrode 106 and the second electrode 107 to the charged electrophoretic particles 105. On the other hand, as the scattering layers 108A and 108B, a material in which a plurality of materials having different refractive indexes are mixed so as to scatter light, for example, a resin layer in which titanium oxide particles are dispersedly arranged is used.

  By the way, the charged electrophoretic particles 105 dispersed in the insulating liquid 104 described above have a property of moving (migrating) by receiving an electric field applied by the first electrode 106 and the second electrode 107. The electrophoretic display device 100 performs display by utilizing this electrophoretic phenomenon.

  Specific examples of the display state by the electrophoresis phenomenon are shown in FIGS. For example, the pixel a shown in the left half of FIGS. 1 and 2 has an electric field applied by the first electrode 106 and the second electrode 107 so that the charged electrophoretic particles 105 become the peripheral portion of the pixel a. A state of accumulation in the vicinity (accumulation part) is formed. When the charged electrophoretic particles 105 are accumulated in the accumulation portion, the incident lights 109A to 109C are reflected by the first electrode 106 that is not covered with the charged electrophoretic particles 105, and the pixel a is in a bright display state.

  Further, the pixel b shown in the right half of FIGS. 1 and 2 shows a state in which the charged electrophoretic particles 105 are distributed in the vicinity of the first electrode 106 due to the electric field applied by the first electrode 106 and the second electrode 107. ing. When the charged electrophoretic particles 105 are distributed in the vicinity of the first electrode 106, even if incident light 109A to 109C as shown in the pixel a is incident, the charged electrophoretic particles 105 are absorbed, and the pixel b is darkly displayed. It becomes a state.

  Note that a unit having the above-described configuration and capable of forming one display state such as bright display and dark display is a pixel. Thus, for example, even if the pixel a as described above is further divided into two regions by a partition wall, one pixel may be formed in the two regions as long as one display state can be formed as a whole. This will be described with reference to FIG.

  Here, the light scattering process by the scattering layers 108A and 108B according to the first embodiment will be described. First, the scattering layer 108A shown by the pixel a in FIGS. 1 and 2 is a layer having a higher scattering property than the scattering layer 108B. This is because the incident light 109A incident through the scattering layer 108A becomes the scattered light 110A scattered in a wide range, so that the reflected light spreads and a wide viewing angle is maintained as a pixel.

  In addition, the scattering layer 108B indicated by the pixel a in FIGS. 1 and 2 is a layer having a lower scattering property than the scattering layer 108A. This is because the incident lights 109B and 109C incident through the scattering layer 108B become scattered lights 110B and 110C scattered in a narrow range, and are not scattered by the partition wall 103 or the charged electrophoretic particles 105 forming the accumulation portion at the time of bright display. In addition, the absorption of the scattered light 110B and 110C by the partition wall 103 and the charged electrophoretic particles 105 can be reduced, and the loss of the incident light 109B and 109C is suppressed.

  On the other hand, in the dark display state shown by the pixel b in FIG. 1 and FIG. 2, incident light is scattered by the scattering layers 108A and 108B, so that much light is scattered by the charged electrophoretic particles 105 distributed on the first electrode 106. Will be absorbed. As a result, less light is reflected in the dark display state when the scattering layers 108A and 108B are provided than when the scattering layers 108A and 108B are not provided.

  Next, a more detailed example of the particle movement type display device 100 according to the first embodiment will be described. The following shows the configuration of the particle movement type display device 100 with specific numerical values.

  For example, the vertical and horizontal lengths of the pixels a and b of the particle movement display device 100 shown in FIG. 1 are 100 μm × 100 μm. The second substrate 102 is a glass substrate having a thickness of 1.1 mm, and a partition wall 103 is disposed at the boundary between the pixels. The width of the partition wall 103 is 5 μm and the height is 18 μm. The first electrode 106 has a width of 90 μm and a thickness of 0.1 μm, and is arranged according to the center position of each pixel. Further, the second electrode 107 is disposed on the partition wall 103 in the vicinity of the insulating liquid 104 and the scattering layer 108, and has a width of 5 μm and a thickness of 0.1 μm.

  Each pixel is filled with an insulating liquid 104 and charged electrophoretic particles 105. Isoparaffin (trade name: Isopar, manufactured by Exxon) is used for the insulating liquid 104, and polystyrene-polymethyl methacrylate copolymer resin containing carbon black having a particle size of about 1 to 2 μm is used for the charged electrophoretic particles 105. . The isoparaffin contains succinimide (trade name: OLOA 1200, manufactured by Chevron Co., Ltd.) as a charge control. Further, Al is used for the first electrode 106 in order to obtain a high reflectance.

Further, by controlling the sphere diameter and the number of fine particles (silica) in the transparent resin (polyacetyl cellulose) used in the scattering layers 108A and 108B shown in FIG. 1 with the scattering layer 108A or the scattering layer 108B, respectively, the scattering layer The haze value of 108A is 90%, and the haze value of the scattering layer 108B is 30%. Here, the haze value is a value that means a haze value in JIS-K7105,
H = Td / Tt × 100 (%) [H: haze, Td: scattered light transmittance, Tt: total light transmittance]
It can be obtained from the following formula.

  In the scattering layers 108 </ b> A and 108 </ b> B that also function as the first substrate 101, a curable resin layer (sealing layer) (not shown) is disposed so as to be in contact with the insulating liquid 104. As the material of the curable resin layer, a mixture mainly composed of polyethylene glycol methacrylate is used.

  A thin film transistor (TFT) (not shown) is formed in each pixel of the particle movement type display device 100, and a voltage application circuit (not shown) is connected to the pixel to form a display device.

  When the particle movement type display device 100 configured with specific numerical values as described above is driven and light is incident from the normal direction 30 ° of the observation surface, the reflectivity during bright display in the 0 ° direction is 50%. The scattered light absorbed by the charged electrophoretic particles 105 collected in the vicinity of the partition wall 103 is reduced, and a bright image quality can be obtained.

  As described above, according to the particle movement type display device 100 according to the first embodiment, the regular scattering layers having different scattering properties such as the scattering layers 108 </ b> A and 108 </ b> B are arranged on the first substrate 101. Since the reflectance as a pixel can be increased, a bright and highly visible display screen can be obtained.

  Further, according to the particle movement type display device 100 according to the first embodiment, the scattering layer 108A having a high scattering property is disposed in the center of the pixel, and the scattering layer 108B having a low scattering property is disposed in the periphery of the pixel. Thus, the scattered light is prevented from being scattered by the partition wall 103 and the charged electrophoretic particle 105 accumulation portion that is collected in the vicinity of the partition wall 103, thereby suppressing the incident light 109B and 109C from being absorbed by the partition wall 103 and the charged electrophoresis particle 105. Therefore, the reflectance as a pixel can be improved.

  Further, according to the particle movement type display device 100 according to the first embodiment, the scattering characteristics such as the scattering layers 108A and 108B in the dark display state in which the charged electrophoretic particles 105 are distributed in the vicinity of the first electrode 106. By disposing the scattering layer including the above, the scattered electrophoretic particles 105 can absorb more scattered light scattered by the scattering layers 108A and 108B, and the reflectance during dark display of the pixels can be reduced. The difference in reflectance between display and dark display can be increased.

  In the first embodiment, the particle movement type display device 100 shown in FIG. 1 has been described as including two layers of the scattering layer 108A having a high scattering property and the scattering layer 108B having a low scattering property. However, the present invention is not particularly limited to this configuration, and the configuration is such that the scattered light 110B and the scattered light 110C as shown in FIG. do it.

  Further, in the first embodiment, the scattering layer 108B shown in FIG. 1 has been described as the layer on the first substrate 101 from the partition wall 103 to the scattering layer 108A. In the case where the scattered light 110B and 110C is not scattered in the accumulation portion 105, the scattering layer 108B may be formed from the inside of the pixel to the scattering layer 108A by the width of the accumulation portion of the charged electrophoretic particles 105. At this time, the first substrate 101 corresponding to the width of the accumulation portion of the charged electrophoretic particles 105 may be scattering or transmissive. Desirably, in order to improve the reflectance of a pixel, it is good to have a scattering property or refractive index which scatters scattered light in the center part of a pixel.

  In the first embodiment, the second electrode 107 is described as being disposed below the partition wall 103 and in the vicinity of the first substrate 101. However, the second electrode 107 is disposed inside the partition wall 103 or the partition wall 103. The location is not particularly limited, for example, between the first substrate 102 and the second substrate 102.

<Second Embodiment>
Next, a particle movement type display device having four different types of scattering layers according to the second embodiment of the present invention will be described with reference to FIGS. FIG. 3 is a cross-sectional view showing an example of a particle movement type display device having four different scattering layers according to the second embodiment, and FIG. 4 has four different scattering layers according to the second embodiment. It is a top view which shows an example of a particle movement type display apparatus. The particle movement type display device 300 according to the second embodiment is a partial modification of the first embodiment, and the same reference numerals as those in FIG. 1 in FIG. 3 and FIG. An equivalent part is shown and the description is abbreviate | omitted including another identical part.

  The particle movement type display device 300 shown in FIGS. 3 and 4 is in a bright display state in which the charged electrophoretic particles 105 form an accumulation portion in the vicinity of the second electrode 107. In addition, the particle movement type display device 300 shows one pixel, and the first substrate 101 in the pixel has a scattering layer 201A to 201D distributed in a layer shape, and also functions as the first substrate 101.

  Here, light scattering by the scattering layers 201A to 201D according to the second embodiment will be described. 3 and 4, scattering layers 201 </ b> A to 201 </ b> D are arranged in order from a layer having a high scattering property to a layer having a low scattering property. Among these, the scattering property of the scattering layer 201A is the highest, and the incident light is scattered in the widest range. The other scattering layers 201B, 201C, and 201D have lower scattering properties in order, and the range in which incident light is scattered also becomes narrower according to the respective scattering properties.

  When the scattering layers 201 </ b> A to 201 </ b> D having the scattering properties as described above are configured, the light scattered by the scattering layers 201 </ b> A to 201 </ b> D irradiates the integrated portion of the partition wall 103 and the charged electrophoretic particles 105 shown in FIGS. 3 and 4. It becomes scattered to the extent of not being done. Thereby, the scattering layers 201 </ b> A to 201 </ b> D suppress the scattered light from being absorbed by the partition walls 103 and the charged electrophoretic particles 105.

  Next, a more detailed example of the particle movement type display device 300 according to the second embodiment will be described. The following shows the configuration of the particle movement type display device 300 with specific numerical values.

  The first substrate 101 is a scattering layer having four types of scattering characteristics. By controlling the particle size and number of silica fine particles in the scattering layers 201A to 201D, the haze value of the scattering layer 201A is 90% The haze value of the layer 201B is 70%, the haze value of the scattering layer 201C is 50%, and the haze value of the scattering layer 201D is 30%. The configuration other than the scattering layers 201 </ b> A to 201 </ b> D has the same conditions as in the detailed example shown in the first embodiment.

  As a result, light is incident from the normal direction 30 ° of the observation surface, the reflectivity during bright display in the 0 ° direction is 60%, and the scattered light absorbed by the charged electrophoretic particles 105 collected in the vicinity of the partition wall 103 is reduced. In addition, high contrast can be achieved.

  As described above, according to the particle movement type display device 300 according to the second embodiment, the scattering layers 201A to 201D whose scattering properties become lower in order from the central portion of the pixel to the peripheral portion of the first substrate 101. As a result of the distribution, it is possible to suppress the absorption of scattered light by the partition wall 103 and the charged electrophoretic particles 105 located in the periphery of the pixel, so that the reflectance as the pixel can be improved.

  According to the second embodiment, the first substrate 101 as shown in FIGS. 3 and 4 has been described as having four types of scattering layers, but the number of scattering layers is not limited. You may comprise a scattering layer in arbitrary kinds. Further, the scattering layer having a different scattering property is configured in a line shape as shown in FIG. 4, but the scattering layer is designed so that the scattered light is not scattered on the partition wall 103 or the accumulation portion of the charged electrophoretic particles 105 at the time of bright display. For example, the shape of the scattering layer is not limited to this.

  Further, according to the second embodiment, the scattering layer 201D shown in FIG. 3 has been described as the layer on the first substrate 101 from the partition wall 103 to the scattering layer 201C. In the case where scattered light is not scattered in the accumulation portion of the particles 105, the scattering layer 201D may be formed from the inside of the pixel to the scattering layer 201C by the width of the accumulation portion of the charged electrophoretic particles 105. At this time, the first substrate 101 corresponding to the width of the accumulation portion of the charged electrophoretic particles 105 may be scattering or transmissive. Desirably, in order to improve the reflectance of a pixel, it is good to have a scattering property or refractive index which scatters scattered light in the center part of a pixel.

<Third Embodiment>
Next, an example of a particle movement type display device including a plurality of scattering layers having different scattering properties according to the third embodiment of the present invention will be described with reference to FIG. FIG. 5 is a cross-sectional view illustrating an example of a particle movement type display device including a plurality of scattering layers having different scattering properties according to the third embodiment. The particle movement type display device 500 according to the third embodiment is a partial modification of the first embodiment. In FIG. 5, the same reference numerals as those in FIG. The description is omitted including other identical parts.

  The particle movement type display device 500 shown in FIG. 5 is in a bright display state in which the charged electrophoretic particles 105 form an accumulation portion in the vicinity of the second electrode 107. In addition, the particle movement display device 500 shows one pixel, and the first substrate 101 in the pixel also functions as a scattering layer, and the central portion of the pixel is thicker than the peripheral portion. It has a thick semicircular kamaboko shape. In the first substrate 101, the central portion of the thickest pixel is formed with the highest scattering property, and the scattering property becomes lower as it approaches the partition wall 103.

  The incident light 501A incident on the center portion of the first substrate 101 shown in FIG. 5 is incident on a position where the scattering property of the first substrate 101 is high, and thus becomes scattered light 502A scattered in a wide range, and a wide field of view as a pixel. Keep the corner.

  On the other hand, incident light 501B and 501C incident on the peripheral portion of the first substrate 101 are incident on a position where the scattering property of the first substrate 101 is low, and thus become scattered light 502B and 502C scattered in a narrow range. It does not scatter to the accumulation part of the charged electrophoretic particles 105 accumulated in the vicinity of 103. Therefore, the amount of scattered light 502B and 502C absorbed by the partition wall 103 and the charged electrophoretic particles 105 can be reduced, and the loss of incident light 501B and 501C is suppressed.

  In the dark display state (not shown), incident light is scattered by the first substrate 101, so that much light is absorbed by the charged electrophoretic particles 105 distributed on the first electrode 106. Thereby, the reflected light in the dark display state is further reduced as compared with the case where the scattering layer of the first substrate 101 is not provided.

  As described above, according to the particle movement type display device 100 according to the third embodiment, by using the first substrate 101 whose scattering property is continuously lowered from the central part to the peripheral part of the pixel. Since it is possible to suppress the absorption of scattered light by the partition walls 103 and the charged electrophoretic particles 105 located in the periphery of the pixel, the reflectance as the pixel can be improved.

  In the third embodiment, the first substrate 101 which is a scattering layer has been described as having a scattering property that continuously changes from the partition wall 103 toward the center of the pixel. In the case where the scattered light is not scattered on the accumulation portion 105, the scattering property of the first substrate 101 may be changed from the inside of the pixel toward the center portion of the pixel by the width of the accumulation portion of the charged electrophoretic particles 105. Good. At this time, the first substrate 101 corresponding to the width of the accumulation portion of the charged electrophoretic particles 105 may be scattering or transmissive. Desirably, in order to improve the reflectance of a pixel, it is good to have a scattering property or refractive index which scatters scattered light in the center part of a pixel.

  In the third embodiment, it has been described that the first substrate 101 has a semi-cylindrical shape. However, the scattering property of the central portion of the pixel is high and the scattering property is decreased toward the peripheral portion of the pixel. If a regular distribution can be formed, the shape of the first substrate 101 is not limited to this.

<Fourth embodiment>
Next, an example of a particle movement type display device having pixels composed of sub-pixels according to the fourth embodiment of the present invention will be described with reference to FIG. FIG. 6 is a cross-sectional view showing an example of a particle movement type display device having pixels composed of sub-pixels according to the fourth embodiment. The particle movement type display device 600 according to the fourth embodiment is a partial modification of the first embodiment. In FIG. 6, the same reference numerals as those in FIG. The description is omitted including other identical parts.

  In the particle movement type display device 600 shown in FIG. 6, one pixel is constituted by sub-pixels a1 and b1, and the outer shape of the one pixel is formed by a partition wall 601a and a partition wall 601b. The particle movement type display device 600 is also partitioned in the depth direction by a partition wall made of the same material as the partition walls 601a and 601b. The subpixel a1 and the subpixel b1 are separated by a transparent partition wall 601c, and the first electrode 106 common to the subpixels a1 and b1 is disposed on the second substrate 102. Here, the particle movement type display device 600 shown in FIG. 6 is in a bright display state in which the charged electrophoretic particles 105 form an accumulation portion in the vicinity of the second electrode 107.

  In the particle movement type display device 600 in FIG. 6, the partition wall 601c that partitions the sub-pixel a1 and the sub-pixel b1 is transparent. A scattering layer that does not proceed is formed. For example, the scattering property of the central portion of the first substrate 101 that is the central portion of the pixel is increased, and the scattering property of the peripheral portion of the pixel in which the partition wall 601a and the partition wall 601b are disposed is decreased. As a result, scattered light is not scattered in the accumulation portion of the charged electrophoretic particles 105 accumulated in the vicinity of the partition walls 601a and b and the partition walls 601a and b, and the loss of incident light (not shown) is suppressed.

  When the partition wall 601c that partitions the sub-pixel a1 and the sub-pixel b1 is colored, a scattering layer is formed so that the scattered light does not proceed to the partition wall 601c, similarly to the partition walls 601a and 601b. In this case, for example, in the case of the sub-pixel a1, the scattering property of the central portion is increased, and the scattering property is decreased toward the peripheral partition wall 601a and the colored partition wall 601c. The sub-pixel b1 has the same configuration.

  As described above, according to the particle movement type display apparatus 600 according to the fourth embodiment, one pixel is composed of the sub-pixel a1 and the sub-pixel b1, so that a plurality of pixels are included in one pixel. Even when the sub-pixel is included, the absorption of scattered light by the partition walls 601a and 601b and the charged electrophoretic particle 105 accumulation portion located in the peripheral portion of the pixel can be suppressed. The rate can be improved.

  In the fourth embodiment, the first substrate 101, which is a scattering layer (not shown), has been described as having a scattering property that continuously changes from each of the partition walls 601a and 601b toward the center of the pixel. In the case where the scattered light is not scattered in the accumulation portion of the charged electrophoretic particles 105 at the time of bright display, the first substrate 101 is scattered from the inside of the pixel toward the center portion of the pixel by the width of the accumulation portion of the charged electrophoretic particle 105. You may make it change sex. At this time, the first substrate 101 corresponding to the width of the accumulation portion of the charged electrophoretic particles 105 may be scattering or transmissive. Desirably, in order to improve the reflectance of a pixel, it is good to have a scattering property or refractive index which scatters scattered light in the center part of a pixel.

  In the first to fourth embodiments described above, in order to perform black and white display using the particle moving display devices 100, 300, 500, and 600, the charged electrophoretic particles 105 are black, The charged electrophoretic particles 105 may be driven by a shutter. On the other hand, in order to perform color display, the charged electrophoretic particles 105 may be colored, or other members may be colored appropriately. For example, in the particle movement type display device 100 shown in FIG. 1, color display is possible by using the black electrophoretic particles 105 and forming a color filter layer on the first substrate 101.

  In the first to fourth embodiments, the scattering layer shown by the scattering layers 108A and 108B in FIGS. 1 and 2 is a mixture of a plurality of materials having different refractive indexes, for example, titanium oxide particles. However, any method may be used as long as the scattering characteristics can be designed. For example, the scattering layer may be made of a transparent resin and spherical fine particles having different refractive indexes, or may be one in which spherical fine particles are dispersed in a coating film provided on the surface of the transparent resin.

  Also, in the first to fourth embodiments, the scattering characteristics of the scattering layers shown by the scattering layers 108A, 108B, etc. in FIGS. 1 and 2 can be designed as long as the desired scattering characteristics are obtained. You may produce by the method. For example, the refractive index, particle size, shape, number, or thickness of the scattering layer with respect to the transparent resin of the scattering layer is appropriately designed for the scattering layer in the pixel.

  As described above, the particle movement type display device according to the present invention is useful when displaying as a reflection type display device, and in particular, a display screen of a portable information terminal or the like that is required to display bright and highly visible. It is suitable for a particle movement type display device.

Sectional drawing of two adjacent pixels of the particle movement type display apparatus concerning 1st Embodiment. FIG. 3 is a top view of two adjacent pixels of the particle movement type display device according to the first embodiment. Sectional drawing which shows an example of the particle movement type display apparatus which has four types of different scattering layers concerning 2nd Embodiment. The top view which shows an example of the particle movement type display apparatus which has four types of different scattering layers concerning 2nd Embodiment. Sectional drawing which shows an example of the particle | grain movement type display apparatus provided with the scattering layer which has several different scattering property concerning 3rd Embodiment. Sectional drawing which shows an example of the particle movement type display apparatus which has a pixel comprised from the subpixel concerning 4th Embodiment.

Explanation of symbols

100, 300, 500, 600 Particle movement type display device 101 First substrate (scattering layer)
102 Second substrate 103, 601a, 601b Partition wall 105 Electrophoretic particles (particles)
106 1st electrode (reflection layer)
108A, 108B, 201A, 201B, 201C, 201D scattering layers a, b, a1, b1 pixels

Claims (7)

A first substrate and a second substrate disposed at positions facing each other with a predetermined gap; a partition wall that partitions a gap between the first substrate and the second substrate; the first substrate; A plurality of particles enclosed in a gap surrounded by a second substrate and the partition; a scattering layer disposed on the first substrate; and the first opposing on the second substrate. In a particle movement type display device having a plurality of pixels formed by a reflective layer disposed between the substrate and a plurality of electrodes disposed close to the gap,
In the pixel, the scattering layer has a distribution with different scattering properties.   2. The particle movement display according to claim 1, wherein the scattering layer has a different scattering property in the pixel according to a distance from the partition that forms a boundary of the pixel toward a central portion of the pixel. apparatus.   The scattering layer has a scattering property that varies depending on a distance from an accumulation portion toward a central portion of the pixel when the plurality of particles are accumulated in a peripheral portion of the pixel in the pixel. Item 4. The particle movement type display device according to Item 1.   3. The particle movement display according to claim 2, wherein the scattering layer has a high scattering property in the pixel in accordance with a distance from the partition that forms a boundary of the pixel toward a central portion of the pixel. apparatus.   4. The particle movement display device according to claim 3, wherein the scattering layer has a high scattering property in the pixel in accordance with a distance from the integrated portion toward the central portion of the pixel.   The particle movement type display device according to claim 4, wherein the haze value of the scattering layer increases in accordance with a distance from the partition toward the center of the pixel. The particle movement type display device according to claim 5, wherein the haze value of the scattering layer is increased according to a distance from the integrated portion toward a pixel central portion.

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