JP2013007985A - Electrophoretic display device and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophoretic display device capable of preventing a reduction in contrast and of displaying desired colors while being provided with desired resistance strength against force applied to a surface, and further to provide a manufacturing method of the electrophoretic display device capable of easily manufacturing the electrophoretic display by using existing techniques.SOLUTION: An electrophoretic display device of the present invention comprises: partition walls that are disposed between a first substrate and a second substrate disposed opposite to each other and have reflectivity while having a plurality of cells corresponding to pixel regions; an electrophoretic layer that is configured such that an electrophoretic material is held in each of the plurality of cells; first electrodes provided on an electrophoretic layer side surface of the first substrate; a second electrode provided on an electrophoretic layer side surface of the second substrate; and reflecting portions that are provided corresponding to each of the plurality of cells in the partition walls and have inclined surfaces inclined at a predetermined inclination angle θ toward cell sides with respect to a normal direction perpendicular to surfaces of the first substrate and the second substrate.

Description

  The present invention relates to an electrophoretic display device and a method for manufacturing the same.

  In an electrophoretic display device, a configuration in which an electrophoretic dispersion liquid (in which electrophoretic particles are dispersed in a dispersion medium) is enclosed in each cell partitioned by a partition formed between a pair of substrates is known. (For example, Patent Document 1).

  By the way, if the width of the partition wall is large, the portion that can be involved in the display decreases, the aperture ratio decreases, and the display becomes dark and low in contrast. Therefore, a configuration is known in which the partition wall has a trapezoidal shape in which the cross-sectional shape is narrow on the observation surface side and wide on the opposite side of the observation surface (for example, Patent Document 2).

JP 2004-4773 A JP 2003-208107 A

  However, if the width of the partition wall on the observation surface side is too narrow, the surface pressing resistance strength becomes weak. For example, when applying an electrophoretic display device to electronic paper with a pen input function, the pressure of the pen There is a problem that the partition wall is easily crushed. That is, there is a problem that increasing the aperture ratio is not compatible with increasing the surface pressing resistance strength.

  In the partition-type electrophoretic display device, all of the light incident from the outside may not enter the cells but enter the partitions. The light incident on the transparent partition is reflected by the backplane, and white light is emitted to the outside as it is. Since it does not pass through the electrophoretic layer (cell), a desired color display cannot be obtained as a whole. The light incident on the partition walls made of resin is attenuated and transmitted, so there is a problem that the amount of light is reduced when displaying white, and when displaying black, it is clear that white is mixed with the black background. There is a problem that black display cannot be obtained. As described above, another problem that the contrast of the display color is lowered has occurred.

  The present invention has been made in view of the above-described problems of the prior art, and has an electrophoretic display device that has a desired surface pressing resistance strength and can prevent a decrease in contrast and display a desired color, and an existing display device. An object of the present invention is to provide a method for manufacturing an electrophoretic display device that can be easily manufactured using technology.

  An electrophoretic display device according to the present invention includes a first substrate and a second substrate disposed to face each other, a partition wall disposed between the first substrate and the second substrate, having a plurality of cells and having reflectivity. An electrophoretic layer in which an electrophoretic material is held in each cell, a first electrode provided on a surface of the first substrate on the electrophoretic layer side, and an electrophoretic layer side of the second substrate A second electrode provided on a surface; and a reflective portion provided in the partition, wherein the partition is formed of a transparent member at least on the display surface side than the reflective portion.

  According to this, it is possible to effectively use the light incident from the outside for display by reflecting the light incident from the outside into the partition wall and reflecting the light into the cell. Raising the contrast can improve the contrast. Moreover, since the aperture ratio can be improved without reducing the width of the partition wall by providing the reflecting portion, the surface pressing resistance strength can be increased.

In the electrophoretic display device, it is preferable that the reflecting portion is provided corresponding to each cell.
According to this, since a reflection part is provided corresponding to every cell, it can guide light efficiently into each cell.

In the electrophoretic display device, the transparent member preferably has substantially the same refractive index as the electrophoretic material.
According to this, it is possible to make it difficult for light to be reflected at the interface between the transparent member and the electro-optical member.
In the electrophoretic display device, the electrophoretic material preferably includes a dispersion medium and electrophoretic particles. Furthermore, it is more preferable that the dispersion medium or the electrophoretic particles have substantially the same refractive index as that of the transparent member.
According to this, reflection of light can be made difficult to occur at the interface between the transparent member and the dispersion medium or electrophoretic particles contained in the electro-optical member.

In the electrophoretic display device, it is preferable that a height h from the first substrate to the tip of the reflecting portion is in a range of d / 2 ≦ h ≦ d with respect to the cell gap d.
According to this, since the external light incident on the partition wall from the second substrate side can be guided into the cell without being attenuated, a reduction in luminance can be prevented.

In the electrophoretic display device, it is preferable that the reflection portion includes a scattering surface that scatters light in the cell.
According to this, the light incident on the partition wall from the outside can be favorably reflected by the scattering surface provided in the partition wall to be guided into the cell.

Further, in the electrophoretic display device, it is preferable that the reflection portion is constituted by an optical member provided in the partition wall.
According to this, the light incident on the partition wall from the outside can be favorably reflected by the optical member provided in the partition wall and guided to the cell.

In the electrophoretic display device, the plurality of optical members are dispersed in the partition along a direction inclined at a predetermined angle toward the cell side with respect to a normal direction perpendicular to the substrate surface. More desirable.
According to this, since the plurality of optical members are dispersed along the direction inclined at a predetermined angle in the partition wall, the light incident on the partition wall can be efficiently reflected in the cell.

  In addition, the electrophoretic display device of the present invention is disposed between the first substrate and the second substrate that are arranged to face each other, and between the first substrate and the second substrate, and has a plurality of cells and has reflectivity. A partition, an electrophoretic layer in which an electrophoretic material is held in each cell, a first electrode provided on a surface of the first substrate on the electrophoretic layer side, and the electrophoretic layer of the second substrate A second electrode provided on the side surface, and an inclined surface provided corresponding to each cell in the partition, and inclined at a predetermined angle θ toward the cell side with respect to a normal direction perpendicular to the substrate surface And a reflection part having the above.

According to this, the light incident on the partition wall from the outside can be reflected by the reflecting portion and guided into the cell. As a result, light incident from the outside can be effectively used for display, and the contrast can be improved. Further, even when a plurality of pixels correspond to one cell, the above-described effect can be obtained in the pixel in contact with the partition wall.
Note that a structure in which one pixel corresponds to one cell may be employed.

Further, the angle θ may be in a range of 30 ° ≦ θ ≦ 60 °.
According to this, it is possible to efficiently guide the external light incident on the partition wall from the second substrate side into the cell.

Moreover, it is good also as a structure where the said reflection part corresponding to the said several cell arranged in one direction inclines in the same direction.
According to this, external light can be uniformly introduced into a plurality of cells arranged in one direction.

In addition, the reflection portion includes a first inclined surface that is inclined toward one of the cells adjacent to the partition via the partition wall, and a second inclined surface that is inclined toward the other cell side. Also good.
According to this, light can be guided to a pair of adjacent cells via the partition.

Further, the reflecting portion may be made of a metal film.
According to this, since the reflecting portion is made of a metal film, it can be easily formed by using a sputtering method, a vapor deposition method, or the like.

In addition, the partition includes a first partition part and a second partition part combined with the first partition part, and the reflection part is disposed between the first partition part and the second partition part. It is good also as composition which has.
According to this, it is easy to form the reflection portion at a predetermined position in the partition wall.

Moreover, it is good also as a structure in which the said partition contains the white pigment.
According to this, it is possible to scatter external light incident on the partition walls and guide the light into each cell.

In addition, one cell may correspond to one pixel.
Thereby, since the brightness | luminance of each pixel can be raised, it is possible to improve contrast more.

In addition, the reflection unit may be configured of fine particles including white fine particles or metal fine particles that are embedded in the partition walls to guide light entering the partition walls into the cells.
According to this, the external light incident on the partition wall can be reflected by the fine particles embedded in the partition wall and guided to each cell.

Further, a fine particle-free region where the fine particles are not present is set on the second substrate side of the partition, and the height of the fine particle-free region is 1/8 or more of the height of the partition 1 / It may be within a range of 2 or less.
According to this, it is possible to efficiently guide the external light incident on the partition wall from the second substrate side into the cell.

In addition, when the amount of the fine particles that can be arranged in the partition wall in a plan view is a, the amount of the fine particles embedded in the partition wall may be in the range of 2a to 8a.
According to this, since the fine particles are satisfactorily arranged in the partition wall, it is possible to efficiently guide the external light incident on the partition wall into the cell.

  In the method for manufacturing an electrophoretic display device of the present invention, a first partition wall section that partitions a plurality of pixel regions is formed on a first base material, and the second partition corresponding to the first partition wall section is formed on a second substrate. Forming a partition wall; forming a first engagement portion on an upper surface of the first partition wall portion; and forming a second engagement portion corresponding to the first engagement portion on an upper surface of the second partition wall portion. A step of forming a reflection portion on at least one of the first engagement portion and the second engagement portion, and the first engagement portion and the second engagement portion facing each other. A step of forming a partition by combining the first partition and the second partition, a step of bonding the partition on the first substrate, and at least an electric current in a cell surrounded by the partition and the first substrate. A step of filling the electrophoretic material, and the partition on the first substrate. And having a step of bonding the second substrate.

  According to this, since the reflection part can be formed at a predetermined position in the partition wall, it is possible to guide the outside light incident on the partition wall into the cell without being attenuated.

Further, the first engaging portion has a convex shape and the second engaging portion has a concave shape, and when the partition wall is bonded onto the first substrate, the convex first engaging portion is It is good also as a structure which bonds the said 1st partition part in the state which faced the opposite side to the 1st board | substrate.
According to this, by bonding the second partition wall portion on the first substrate in a state where the convex first engaging portion is directed to the side opposite to the first substrate (that is, the second substrate side), Light can be introduced into each cell existing on both sides of the partition wall by the reflection section existing between the first partition wall portion and the second partition wall portion.

1 is a cross-sectional view illustrating a schematic configuration of an electrophoretic display device that is an example of an electro-optical display device of the present invention. The top view which shows centering on a reflection part about the structure of a partition. Sectional drawing which shows centering on the structure of a partition about schematic structure of an electrophoretic display device. Explanatory drawing about the effect of an electrophoretic display device. The figure which shows the cross-sectional shape of a reflection part. The top view which shows the modification of a partition. The figure which shows the structure which concerns on another form of a reflection part. The figure which shows the structure which concerns on another form of a reflection part. The figure which shows the flow of the manufacturing process of an electrophoretic display device. Sectional drawing which shows the manufacturing process of an electrophoretic display device. Sectional drawing which shows the manufacturing process of an electrophoretic display device.

  Embodiments of the present invention will be described below with reference to the drawings. In each drawing used for the following description, the scale of each member is appropriately changed to make each member a recognizable size.

FIG. 1 is a cross-sectional view showing a schematic configuration of an electrophoretic display device which is an example of an electro-optical display device of the present invention.
As shown in FIG. 1, an electrophoretic display device (electro-optical display device) 100 includes an element substrate 300 including a first substrate 30 and a pixel electrode (first electrode) 35, a second substrate 31, and a counter electrode (second electrode). Electrophoresis layer 32 is sandwiched between counter substrate 310 including electrode 37.
In FIG. 1, a partition corresponding to each pixel region is formed. However, the present invention is not limited to this, and a plurality of pixel regions may exist in one region surrounded by the partition.

On the first substrate 30, a pixel transistor (for example, TFT (not shown)), a pixel electrode 35, and a partition wall 14 are provided for each pixel.
The first substrate 30 is a substrate made of an insulating resin material such as polycarbonate (PC) or polyethylene terephthalate (PET) (that is, a resin substrate) or a glass substrate, and has a thickness of 100 to 500 μm. is doing. Note that in the case of providing flexibility to the electrophoretic display device 100, a flexible resin substrate is selected. Further, since the pixel electrode 35 and the first substrate 30 are not on the viewing side, it is not always necessary to use a light-transmitting material, and a non-light-transmitting material can also be used.

  The pixel transistors are respectively connected to the pixel electrodes 35 through wirings, and a voltage can be selectively applied to the pixel electrodes 35 by turning the pixel transistors on and off.

  The pixel electrode 35 is formed on the surface of the element substrate 300 facing the electrophoretic layer 32. The pixel electrode 35 is made of ITO having a thickness of 50 nm, but is not limited thereto. The counter electrode 37 is formed on the surface of the counter substrate 310 that faces the electrophoretic layer 32. The pixel electrode 35 is an electrode formed for each pixel, and the counter electrode 37 is an electrode formed in common over a plurality of pixels. The pixel electrode 35 and the counter electrode 37 are made of a light-transmitting (opaque) conductive film such as aluminum (Al) or a light-transmitting conductive film such as indium tin oxide (ITO). Has been.

  When the element substrate 300 is a transparent substrate and the pixel electrode 35 is made of ITO or the like, characters, images, and the like displayed on the screen can be viewed from the element substrate 300 side. Alternatively, when the counter electrode 37 (not shown) is a transparent substrate and the counter electrode 37 is made of ITO or the like, characters, images, and the like displayed on the screen can be viewed from the counter substrate 310 side. That is, the surface of the counter substrate 310 constitutes the display surface 100 a of the electrophoretic display device 100.

The partition wall 14 is made of a transparent resin, forms a plurality of cells 15 corresponding to the pixel regions on the first substrate 30, and holds an electrophoretic material in each cell 15. In the present embodiment, one cell 15 corresponds to one pixel.
The material constituting the partition wall 14 may be either a flexible material or a hard material such as an epoxy resin, an acrylic resin, a urethane resin, a melamine resin, or a phenol resin. Examples thereof include resin materials and various ceramic materials such as silica, alumina, and titania. However, when plasticity is imparted to the electrophoretic display device 100, a resin material having plasticity is selected.

  In addition, it is preferable to select a material having a high affinity for the electrophoretic layer 32 as a material constituting the partition wall 14. For example, when the electrophoretic layer 32 is oleophilic, the partition wall 14 is preferably made of an oleophilic material. In this case, the partition wall 14 itself may be made of an oleophilic material, or only the surface of the partition wall 14 may be made oleophilic. As a method of making only the surface of the partition wall 14 oleophilic, for example, a lipophilic film is formed on the surface of the partition wall 14 by using a method such as surface treatment (that is, coating, physical vapor deposition or chemical vapor deposition). Treatment or treatment for applying a lipophilic film).

  Furthermore, it is preferable to use a material having substantially the same refractive index as that of the electrophoretic layer 32 (dispersion medium 21 or the like) described later as a material constituting the partition wall 14. In this way, it is possible to prevent reflection of light that occurs at the interface between the partition wall 14 and the electrophoretic layer 32.

  A plurality of reflecting portions 16 corresponding to the respective cells 15 are provided inside the partition wall 14 of the present embodiment. The reflection part 16 is inclined at a predetermined angle and has a function of guiding light incident from the counter substrate 310 side into each cell 15.

  The electrophoretic layer 32 is formed by filling each cell 15 of the partition wall 14 with an electrophoretic material 32A having a plurality of electrophoretic particles 26 and a dispersion medium 21 in which the electrophoretic particles 26 are dispersed. A desired color display is performed for each cell 15 corresponding to the region.

  The electrophoretic particles 26 are, for example, pigment particles, resin particles, or composite particles thereof. Examples of the pigment constituting the pigment particles include black pigments such as aniline black and carbon black, and white pigments such as titanium oxide and antimony oxide. Examples of the resin material constituting the resin particles include an acrylic resin, a urethane resin, a urea resin, an epoxy resin, polystyrene, and polyester. Examples of composite particles include those in which the surface of pigment particles is coated with a resin material or other pigment, the surface of resin particles coated with a pigment, or a mixture in which pigments and resin particles are mixed in an appropriate composition ratio. There are particles and so on. The electrophoretic particles 26 made of these various materials are dispersed in a dispersion medium, for example, in a positively or negatively charged state. The electrophoretic particles 26 according to the present embodiment include black and white particles 26a and white and white particles 26b (see FIG. 3). The black and white particles 26a have light absorption, and the white and white particles 26b have light reflectivity.

The dispersion medium 21 is, for example, a lipophilic hydrocarbon solvent, and includes, for example, Isopar (registered trademark). That is, the dispersion medium 21 is, for example, a liquid containing any one of Isopar E, Isopar G, Isopar H, Isopar L, and Isopar M, or a liquid in which two or more of these are mixed, or these It is the liquid which mixed any one or more of these, and the hydrocarbon solvent of another kind.
In the present embodiment, the constituent material of the partition wall 14 is the same as that of the electrophoretic particles 26 (particle surface material) or the dispersion medium 21. Thus, the partition wall 14 and the electrophoretic particles 26 or the dispersion medium are used. The reflection of the light which arises in the interface with 21 is prevented.

  Alternatively, the dispersion medium 21 includes, for example, aliphatic hydrocarbons such as pentane, hexane, and octane, alicyclic hydrocarbons such as cyclohexane and methylcyclohexane, benzene, toluene, xylene, hexylbenzene, heptylbenzene, octylbenzene, Aromatic hydrocarbons such as benzenes (alkylbenzene derivatives) having a long-chain alkyl group such as nonylbenzene, decylbenzene, undecylbenzene, dodecylbenzene, tridecylbenzene, tetradecylbenzene, pyridine, pyrazine, furan, pyrrole , Aromatic heterocycles such as thiophene and methylpyrrolidone, methyl acetate, ethyl acetate, butyl acetate, ethyl formate and other esters, acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, rutile isopropyl ketone, Ketones such as clohexanone, nitriles such as acetonitrile, propionitrile, acrylonitrile, amides such as N, N-dimethylformamide, N, N-dimethylacetamide, carboxylates or other various oils, etc. These can be used alone or as a mixture.

  FIG. 2 is a plan view showing the configuration of the partition with the reflecting portion as the center, and FIG. 3 is a cross-sectional view showing the schematic configuration of the electrophoretic display device with the configuration of the partition as the center. FIG. 4 is a diagram for explaining the effect of the electrophoretic display device 100 according to the present embodiment.

  As shown in FIGS. 2 and 3, the partition wall 14 having a square lattice shape in plan view is directly attached to the uppermost layer on the pixel electrode 35 side of the element substrate 300. The reflecting portion 16 embedded in the partition wall 14 has a convex shape (a square shape) protruding toward the counter substrate 310 side, and is inclined toward the adjacent one cell 15A side (first inclined surface). Surface) 16a and a second inclined surface (second inclined surface) 16b inclined toward the other cell 15B side. The inclination angle θ of the first inclined surface 16a and the second inclined surface 16b with respect to the normal direction perpendicular to the substrate surface is preferably in the range of 30 ° ≦ θ ≦ 60 °, and more preferably 35 ° ≦ θ ≦ 50 °. Further, the height h of the reflecting portion 16 from the first substrate 30 is set within a range of d / 2 ≦ h ≦ d with respect to the cell gap d. That is, the reflecting portion 16 is provided on the display surface 100a side with respect to half of the cell gap d. The height h of the reflecting part 16 is set by the distance between the tip of the reflecting part 16 and the substrate surface of the first substrate 30.

  Since the partition wall 14 according to the present embodiment is made of a transparent resin as described above, the display surface 100a side of the reflecting portion 16 is made of a transparent member. As a result, light incident from the outside passes through the partition wall 14 and is guided to the reflecting portion 16.

  Since the periphery of the cell 15A is surrounded by the four first inclined surfaces 16a and the periphery of the cell 15B is surrounded by the four second inclined surfaces 16b, the external light incident from the outside into the partition wall 14 is reflected by the reflecting portion. The light is reflected on the 16 inclined surfaces 16a and 16b and enters the adjacent cells 15A and 15B via the reflecting portion 16 (partition wall 14).

  According to the configuration of the present embodiment, out of the external light incident from the outside, the light incident in the partition wall 14 is reflected by the reflecting portion 16 embedded in the partition wall 14 and guided into each cell 15. Therefore, light incident from the outside can be effectively used for display in each cell. That is, the external light incident on the partition wall 14 can be reliably reflected into the cell 15 rather than reflected directly toward the counter substrate 310 side.

  Light from the outside enters the inside of the partition wall 14 made of a transparent resin, is reflected by the inclined surfaces 16a and 16b of the reflecting portion 16, and is guided to the cells 15A and 15B.

  Here, when performing black display, the electrophoretic display device 100 moves the black and white particles 26a of the electrophoretic particles 26 to the display surface 100a side (counter electrode 37 side) and the opposite side (pixel electrode 35) to the display surface 100a. The white particles 26b have moved to the side). Further, in the electrophoretic display device 100, when white display is performed, the white particles 26b of the electrophoretic particles 26 move to the display surface 100a side (counter electrode 37 side), and the side opposite to the display surface 100a (pixel electrode 35 side). The black and white particles 26a are moving.

  In the case of black display, as shown in FIG. 4A, the light guided to the cells 15A and 15B is absorbed by the black white particles 26a. Since the reflecting part 16 is arranged on the display surface 100a side as described above, the light reflected by the inclined surfaces 16a and 16b of the reflecting part 16 is reliably ensured by the black and white particles 26a moving to the display surface 100a side. Will be absorbed.

  On the other hand, in the case of white display, as shown in FIG. 4B, the light guided to the cells 15A and 15B is reflected by the white particles 26b. Further, since the reflecting portion 16 is arranged on the display surface 100a side as described above, the light reflected by the inclined surfaces 16a and 16b of the reflecting portion 16 is more reliably generated by the white particles 26b moving to the display surface 100a side. Will be reflected. The light reflected by the white particles 26b is reflected again by the inclined surfaces 16a and 16b of the reflecting portion 16, passes through the partition wall 14, and is emitted from the display surface 100a.

  Note that the cross-sectional shape of the reflecting portion 16 may be a concave shape that is recessed toward the element substrate 300 side. Here, as shown by the solid line A in FIG. 5, when the angle formed by the inclined surfaces 16a and 16b constituting the reflecting portion 16 is 90 degrees, most of the light in the substantially normal direction of the substrate (counter substrate 310) is absorbed. The light is emitted directly to the substrate side. Therefore, as shown by the one-dot broken line B and the two-dot broken line C in FIG. 5, the angle formed by the inclined surfaces 16a and 16b is larger or smaller than 90 degrees, so that much of the light in the substantially normal direction of the substrate is increased. It is desirable that the light be reflected in another angular direction without being directly emitted to the substrate side.

  Moreover, the reflection part 16 does not necessarily need to be a plane, and may be a curved surface. For example, the cross section of the reflecting portion 16 may be an elliptical mountain shape or valley (U-shaped valley) shape. Of course, there may be undulations in the longitudinal direction of the partition wall 14. This means that the shape of the partition wall 14 is allowed to change slightly depending on the cross-sectional position.

  According to the present embodiment, in the case of white display, the partition 14 portion looks bright, so that it is possible to obtain a high-brightness display in which a reduction in the amount of light is prevented. Further, in the case of black display, the partition 14 portion looks dark. In this manner, the partition wall portion becomes black during black display, and the partition wall portion becomes bright during white display. Therefore, the effective aperture ratio increases, and both bright display and high contrast can be achieved. Therefore, a vivid image display with high contrast can be performed. Further, since the aperture ratio can be increased without reducing the width of the partition wall 14, the physical strength of the partition wall 14 is not lowered. In addition, since the physical strength of the partition wall 14 is not reduced, the electrophoretic display device 100 according to the present embodiment is particularly required to have a surface pressing resistance strength with respect to the display surface 100a. It is suitable as a device application.

  The shape of the partition wall 14 in plan view may be, for example, a hexagonal lattice shape (see FIG. 6) or a triangular lattice shape, and is not limited thereto.

  In addition, as the configuration of the reflecting portion 16, the description has been given by taking as an example a configuration exhibiting a convex shape protruding toward the counter substrate 310 as described above, but the reflecting portion 16 is inclined in one direction as shown in FIG. It is good also as composition to do. In this case, the individual reflecting portions 16 corresponding to the plurality of cells 15 arranged in one direction are inclined in the same direction. According to this, since external light can be uniformly introduced into the plurality of cells 15 arranged in one direction, luminance unevenness in the display device can be eliminated.

  Moreover, as shown in FIG.7 (b), it is good also considering the reflection part 16 as a structure which consists of a surface of a light-scattering state. By providing such a light diffusing function in the partition wall 14, the angle of the light that has entered the partition wall 14 approximately perpendicularly can be changed and can be incident on the cell 15. Therefore, the light incident from the outside can be favorably guided into the cells 15A and 15B by being scattered on the surface of the reflecting portion 16.

  Moreover, as shown in FIG.7 (c), you may make it comprise the reflection part 16 using the some bead (optical member) Bz which has been embedded in the partition 14, and has light reflectivity. In the present embodiment, the plurality of beads Bz are along a direction inclined at a predetermined angle θ with respect to the normal direction perpendicular to the substrate surface, like the first inclined surface 16a and the second inclined surface 16b in the above-described embodiment. Dispersed in the partition wall 14. Here, as the predetermined angle θ, a range of 30 ° ≦ θ ≦ 60 ° is preferable, and 35 ° ≦ θ ≦ 50 ° is more preferable. According to this, the light incident on the partition wall 14 by the plurality of beads Bz can be favorably reflected to the cell 15.

  Further, as shown in FIG. 8, the reflecting portion 16 may be configured by fine particles 50 that are embedded in the partition wall 14 to guide the light incident on the partition wall 14 into the cell 15. FIG. 8A shows a cross-sectional view of this configuration, and FIG. 8B shows a plan view of this configuration.

  The fine particles 50 include white fine particles or metal fine particles. The fine particles 50 are provided in the partition 50 in a state of being unevenly distributed on the element substrate 300 side. As a result, a region 60 in which the fine particles 50 are not present (fine particle non-existing region) 60 is set above the partition wall 14. Here, the height L of the fine particle absence region 60 is in the range of 1/8 to 1/2 of the height of the partition wall 14 when the height of the partition wall 14 is d as shown in FIG. Is set to According to this, the fine particles 50 can satisfactorily take the external light incident in the partition wall 14 into the cell 15.

  Further, the amount of the fine particles 50 embedded in the partition wall 14 is defined as the amount of the fine particles 50 that can be arranged in the partition wall 14 in a plan view (a state in which the electrophoretic display device 100 is viewed from the second substrate 31 side). Is set to a range of 2a to 8a. According to this, the fine particles 50 can be satisfactorily embedded in the partition wall 14.

  As described above, according to the configuration shown in FIG. 8, the external light incident from the display surface 100 a side is reflected into the cell 15 by the fine particles 50 embedded in the partition wall 14. Display can be made. Moreover, the reflection part 16 can be simply configured by embedding the fine particles 50 in the partition wall 14. In this description, the case where the fine particles 50 are unevenly distributed on the element substrate 300 side in the partition wall 14 is described as an example. However, even if the fine particles 50 are embedded throughout the height direction of the partition wall 14. good.

Next, a manufacturing method of the electrophoretic display device in Example 1 will be described.
FIG. 9 is a flowchart illustrating a manufacturing process of the electrophoretic display device. FIG. 10 is a cross-sectional view illustrating the manufacturing process of the electrophoretic display device.
As shown in FIGS. 9 and 10, the manufacturing method of the electrophoretic display device according to the first embodiment includes a partition wall forming step S1, an inclined portion forming step S2, a reflecting portion forming step S3, a partition forming step S4, a partition and It has 1 board | substrate bonding process S5, electrophoretic material filling process S6, a partition and 2nd board | substrate bonding process S7.

  First, in the partition wall forming step S1, the first partition wall 42A for partitioning a plurality of pixel regions is formed on the first base material 41A made of a PET substrate, and the first base material 41B made of the PET substrate is made first. A second partition wall portion 42B corresponding to the partition wall portion 42A is formed.

  Specifically, as shown in FIG. 9A, a photosensitive resin material (for example, a photosensitive epoxy resin) is formed on the surface of the first base material 41A and the second base material 41B, for example, with a thickness of 15 It is applied by spin coating or printing so that the thickness becomes ˜30 μm. The dried coating film 42 is patterned into a lattice shape that partitions a plurality of pixel regions by photolithography using a resist mask RM, and the first substrate 41A and the second substrate 41B are formed as shown in FIG. 9B. A partition wall portion 42 ′ is formed in each.

  Next, in the inclined portion forming step S2, as shown in FIG. 9C, the convex portion (first engaging portion) 43 is formed by performing chamfering by etching from the upper surface side of the first partition wall portion 42A. Then, as shown in FIG. 9D, etching is performed from the upper surface side of the second partition wall portion 42B to form a recess (second engagement portion) 44 corresponding to the protrusion 43.

  Next, in the reflection portion forming step S3, as shown in FIG. 9E, a metal film is formed on the entire surface of the convex portion 43 of the first partition wall portion 42A to form the reflection portion 16. As a method for forming a film on the convex portion 43, film formation in a vacuum such as sputtering or vapor deposition, or other printing methods may be used.

  Next, in the partition wall forming step S4, as shown in FIG. 9 (f), the second partition wall portion 42B is disposed opposite to and bonded to the first partition wall portion 42A so that the convex portion 43 and the concave portion 44 are combined. Thus, the partition wall 14 having the reflective portion 16 is formed. The reflection portion 16 is located at a boundary portion between the first partition wall portion 42A and the second partition wall portion 42B. After bonding the first partition wall portion 42A and the second partition wall portion 42B, the first base material 41A and the second base material 41B are peeled from the partition wall 14.

  In the above embodiment, the case where the entire partition wall 14 is made of a transparent resin and a member constituting the reflection portion 16 is embedded therein has been described as an example. However, the partition wall 14 has a display surface 100a with respect to the reflection portion 16. The opposite side does not necessarily need to be transparent. That is, only the second partition wall portion 42B may be configured from a transparent member, and the first partition wall portion 42A may be configured from a non-transparent member.

  Next, in the partition wall-first substrate bonding step S5, as shown in FIG. 10A, the partition wall 14 is bonded to the element substrate 300 prepared separately. Here, the element substrate 300 has a pixel electrode 35, a transistor, and the like formed for each pixel region on a first substrate 30 made of a resin substrate or a glass substrate. The partition wall 14 is attached to the uppermost layer of the element substrate 300 on the pixel electrode 35 side with an adhesive or the like.

  Next, in step S6 of filling the electrophoretic material, as shown in FIG. 10B, a dispersion medium 21 containing a large number of electrophoretic particles 26 is supplied into each cell 15 of the partition wall 14. Examples of the method for supplying the dispersion medium 21 include various application methods such as a dropping method using a dispenser, an ink jet method (droplet discharge method), a spin coating method, and a dip coating method. It is preferable to use an inkjet method. According to the dropping method or the ink jet method, since the dispersion liquid can be selectively supplied to each cell 15, it can be supplied more reliably into the cell 15 without waste.

  It is preferable to provide a certain waiting time after supplying the electrophoretic material 32 </ b> A into the cell 15. Thereby, as shown in FIG.10 (c), the surface (liquid level) of the electrophoretic material 32A falls in the center part of the cell 15, and the shape by the cross-sectional view becomes concave.

  After that, as shown in FIG. 10D, the electrophoretic material 32A is enclosed in each cell 15 by covering the opening side of the partition wall 14 supplied with the electrophoretic material 32A with the encapsulating film 5. Also good. As a method for forming the encapsulating film 5, for example, a water-soluble polymer is dissolved in water or a hydrophilic liquid (for example, methanol or ethanol) to form a liquid, thereby creating an encapsulating liquid. For example, PVA is selected as the water-soluble polymer, and PVA is dissolved in water to prepare an encapsulating liquid of 3 [wt%] to 40 [wt%] (weight percent). The encapsulating film 5 is formed by applying this encapsulating liquid to the opening side of the partition wall 14 after the electrophoretic material 32A is supplied using a squeegee and drying. While the electrophoretic material 32A is oleophilic, the encapsulating liquid is hydrophilic, so they are not miscible. As described above, the encapsulating film 5 is formed so as to cover the liquid surface of the electrophoretic material 32A supplied into each cell 15 of the partition wall 14, so that the electrophoretic material 32A is sealed in each cell 15 with high hermeticity. can do. Further, since the electrophoretic material 32A and the counter electrode 37 are not in direct contact with each other, corrosion of the counter electrode 37 can be prevented.

  Next, as shown in FIG. 10E, in the partition wall-second substrate bonding step S7, a solid counter electrode 37 and a hot electrode are formed on the entire surface of the second substrate 31 made of a resin substrate or a glass substrate in advance. A counter substrate 310 on which the melt conductive adhesive film 38 is formed is prepared, and the surface on the hot melt conductive adhesive film 38 side of the counter substrate 310 is bonded to the upper surface of the partition wall 14 of the element substrate 300 to thereby oppose the counter substrate 310. The substrate 310 and the element substrate 300 are bonded. The hot-melt conductive adhesive film 38 is made of an adhesive film in which a plurality of transparent metal fillers are dispersed in a thermoplastic polymer that is solid at room temperature. Here, the counter substrate 310 is bonded using a vacuum laminating method.

  Thus, the electrophoretic display device 100 of the present embodiment is obtained by bonding the counter substrate 310 to the element substrate 300 via the partition wall 14.

  According to the method for manufacturing the electrophoretic display device 100 of the present embodiment, after the reflecting portion 16 is formed on the convex portion 43 of the first partition wall portion 42A, the first partition wall portion 42A and the second partition wall portion 42B are combined. Since the partition wall 14 is obtained by this, a desired reflecting portion 16 can be formed at a predetermined position in the partition wall 14. Thereby, the electrophoretic display device 100 capable of efficiently guiding the external light incident in the partition wall 14 to each cell 15 is obtained.

Next, a manufacturing method of the electrophoretic display device in Example 2 will be described.
In Example 2, the first partition wall portion and the second partition wall portion are formed by simultaneously performing the partition wall portion forming step S1 and the inclined portion forming step S2. In the present embodiment, the first partition wall portion 42 </ b> A having the convex portion 43 and the second partition wall portion 42 </ b> B having the concave portion 44 are formed by using the nanoimprint method.
First, a resist is applied to the surfaces of the first base material 41A and the second base material 41B, and a first mold corresponding to the shape of the first partition wall portion 42A is brought into contact with the resist on the first base material 41A and pressed. Then, by pressing the second mold corresponding to the shape of the second partition wall portion 42B against the resist on the second base material 41B, the unevenness (transfer pattern) of each mold is transferred to the resist. Thus, the 1st partition part 42A which has the convex part 43 on the 1st base material 41A is formed, and the 2nd partition part 42B which has the recessed part 44 is formed on the 2nd base material 41B. Subsequent processes are the same as those in the first embodiment.

  As in the present embodiment, by forming the first partition wall portion 42A and the second partition wall portion 42B using the nanoimprint method, it can be formed more easily than photolithography and a fine structure is formed by an inexpensive apparatus. be able to.

  In Example 3, in the partition wall forming step and the inclined portion forming step, a resist containing a white pigment was applied to the surfaces of the first base material 41A and the second base material 41B made of a PET substrate, respectively, and the nanoimprint method described above was applied. The white first partition wall portion 42A and the second partition wall portion 42B are formed. Thereafter, the reflection part forming step is omitted and the process proceeds to the partition wall forming step. The process after forming the partition wall 14 by combining the first partition wall portion 42A and the second partition wall portion 42B is the same as that in the first embodiment.

  Examples of white pigments include titanium oxides such as white rutile type titanium oxide and anatase type titanium oxide, zinc white, lead white, zinc sulfide, aluminum oxide, silicon oxide, zirconium oxide and the like. Further, white pigments having a uniform average particle diameter may be used, or white pigments having different average particle diameters may be used.

  As in the present embodiment, the first partition wall portion 42A and the second partition wall portion 42B formed using a resist containing a white pigment can provide the white partition wall 14 having scattering properties. The external light incident on the partition wall 14 can be scattered and guided into each cell by the partition wall 14 having scattering properties. Further, according to the present embodiment, since the scattering property is imparted by the white pigment, the reflection portion 16 is not necessary, and the reflection portion forming step of forming the metal film by sputtering can be omitted.

Next, a manufacturing method of the electrophoretic display device in Example 4 will be described.
Example 4 is different from the configuration shown in FIG. 8 in that it relates to a method for manufacturing an electrophoretic display device including a reflecting portion 16 composed of fine particles 50 embedded in the entire height direction of the partition wall 14. is there.

  In this embodiment, when forming the reflecting portion 16, first, a predetermined amount of fine particles 50 containing white fine particles or metal fine particles are added to the viscous material (resist) forming the partition 14, and stirred. Here, the addition amount of the fine particles 50 is set in the range of 2a to 8a as described above.

  Subsequently, the partition wall 14 containing the fine particles 50 is formed using a nanoimprint method. Specifically, a resist is applied to the surface of the first base material 41A or the second base material 41B, and a mold corresponding to the shape of the partition wall 14 is brought into contact with the resist on the first base material 41A or the second base material 41B. By applying pressure, the unevenness (transfer pattern) of each mold is transferred to the resist and thermally cured. In this way, the partition wall 14 in which the fine particles 50 are embedded on the first base material 41A or the second base material 41B is formed. Subsequent steps are the same as those in the previous embodiment.

Next, a manufacturing method of the electrophoretic display device in Example 5 will be described.
Example 5 relates to a method of manufacturing the electrophoretic display device shown in FIG. That is, unlike Example 4, the fine particles 50 are arranged unevenly in the partition wall 14.

  In this example, as in Example 4, a resist to which a predetermined amount of fine particles 50 were added was prepared, the resist was applied to the surface of the first base material 41A, and a mold corresponding to the shape of the partition wall 14 was formed on the first base. The lower part of the partition wall 14 in which the fine particles 50 are embedded on the first base material 41A by transferring the mold unevenness (transfer pattern) to the resist by applying pressure to the resist on the material 41A and applying heat. Form.

  Subsequently, a resist to which fine particles are not added is prepared, the resist is applied to the surface of the second base material 41B, and a mold corresponding to the shape of the partition wall 14 is brought into contact with the resist on the second base material 41B and pressed. Thus, the mold irregularities (transfer pattern) are transferred to a resist and thermally cured to form the upper part of the partition wall 14 without the fine particles 50 on the second base material 41B.

  Subsequently, the first base material 41 </ b> A and the second base material 41 </ b> B can be bonded to form the partition wall 14 including the upper part and the lower part of the partition wall 14.

Next, a method for manufacturing an electrophoretic display device in Example 6 will be described.
Example 6 relates to a method of manufacturing an electrophoretic display device in which a part of Example 5 is modified.

  In this example, as in Example 4, a resist to which a predetermined amount of fine particles 50 were added was prepared, the resist was applied to the surface of the first base material 41A, and a mold corresponding to the shape of the partition wall 14 was formed on the first base. By pressing and pressing the resist on the material 41A, the unevenness (transfer pattern) of the mold is transferred to the resist.

  In this embodiment, after the irregularities are transferred, they are left for a predetermined time. Thereby, after the fine particles 50 are submerged in the resist material, the partition walls 14 are formed by thermosetting. In this manner, the partition wall 14 provided in the state where the fine particles 50 are unevenly distributed on the element substrate 300 side can be formed.

  As described above, the preferred embodiments according to the present invention have been described with reference to the accompanying drawings, but the present invention is not limited to the examples. It is obvious for those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea described in the claims. It is understood that it belongs to.

For example, the formation method of the first partition wall portion 42A and the second partition wall portion 42B is not limited, but it is formed by a printing process such as a screen printing method, a relief printing method, a gravure printing method in addition to the photolithography method and the nanoimprint method described above. May be.
Further, in the previous embodiment, the partition structure is such that one cell 15 corresponds to one pixel, but a configuration in which one cell 15 corresponds to a plurality of pixels may be adopted. Even with this configuration, the above-described effect can be obtained in the pixel in contact with the partition wall.

  In the above-described embodiment, the case of an electrophoretic element as an optical element has been described as an example. However, the present invention is not limited to this, and electric paper powder fluid (registered trademark) or colored oil and pigment are used. In the case of an electrowetting element in which pixels are formed from dispersed water and the arrangement of oil and water is changed, the present invention can also apply a partition wall in which a reflecting portion is embedded.

d ... cell gap, h ... height, 14 ... partition wall, 14a ... upper surface, 15 (15A, 15B) ... cell, 16 ... reflecting part, 16a ... inclined surface, 30 ... first substrate, 31 ... second substrate, 32 ... Electrophoresis layer, 32A ... Electrophoretic material, 35 ... Pixel electrode (first electrode), 37 ... Counter electrode (second electrode), 41A ... First substrate, 42A ... First partition, 42B ... Second partition Part, 43 ... convex part (first engaging part), 44 ... concave part (second engaging part), 100 ... electrophoretic display device, 100a ... display surface

Claims (22)

A first substrate and a second substrate disposed opposite to each other;
A partition wall disposed between the first substrate and the second substrate and having a plurality of cells and having reflectivity;
An electrophoretic layer in which an electrophoretic material is held in each cell;
A first electrode provided on the electrophoretic layer side surface of the first substrate;
A second electrode provided on the electrophoretic layer side surface of the second substrate;
A reflection part provided in the partition,
2. The electrophoretic display device according to claim 1, wherein the partition wall is made of a transparent member at least on the display surface side of the reflecting portion.   The electrophoretic display device according to claim 1, wherein the reflection unit is provided corresponding to each cell.   The electrophoretic display device according to claim 1, wherein the transparent member has substantially the same refractive index as the electrophoretic material.   The electrophoretic display device according to claim 3, wherein the electrophoretic material includes a dispersion medium and electrophoretic particles.   The electrophoretic display device according to claim 4, wherein the dispersion medium or the electrophoretic particles have substantially the same refractive index as the transparent member.   The height h from the first substrate to the tip of the reflecting portion is within a range of d / 2 ≦ h ≦ d with respect to the cell gap d. The electrophoretic display device according to item.   The electrophoretic display device according to claim 1, wherein the reflection unit includes a scattering surface that scatters light in the cell.   The electrophoretic display device according to any one of claims 1 to 6, wherein the reflecting portion is configured by an optical member provided in the partition wall.   9. The electricity according to claim 8, wherein the plurality of optical members are dispersed in the partition wall along a direction inclined at a predetermined angle toward the cell side with respect to a normal line direction perpendicular to the substrate surface. Electrophoretic display device.   The electrophoretic display according to claim 1, wherein the reflection portion has an inclined surface that is inclined at a predetermined angle toward the cell side with respect to a normal direction perpendicular to the substrate surface. apparatus.   The electrophoretic display device according to claim 10, wherein an inclination angle of the inclined surface is in a range of 30 ° ≦ θ ≦ 60 °.   The electrophoretic display device according to claim 10 or 11, wherein the reflecting portions corresponding to the plurality of cells arranged in one direction are inclined in the same direction.   The reflecting portion includes the first inclined surface that is inclined toward the one cell side adjacent through the partition wall, and the second inclined surface that is inclined toward the other cell side. The electrophoretic display device according to claim 10 or 11.   The electrophoretic display device according to claim 9, wherein the reflection portion is made of a metal film.   The partition is composed of a first partition and a second partition made of the transparent member in combination with the first partition, and the reflection is between the first partition and the second partition. The electrophoretic display device according to claim 9, wherein a portion is disposed.   The electrophoretic display device according to claim 1, wherein a white pigment is contained in the partition wall.   The electrophoretic display device according to claim 1, wherein one cell corresponds to one pixel.   6. The reflecting portion is configured by fine particles including white fine particles or metal fine particles that are embedded in the partition walls to guide light incident in the partition walls into the cells. The electrophoretic display device according to any one of the above. On the second substrate side of the partition wall, a fine particle absence region where the fine particles are not present is set,
19. The electrophoretic display device according to claim 18, wherein the height of the fine particle absence region is in a range of 1/8 to 1/2 of the height of the partition wall.   The amount of the fine particles embedded in the partition wall is in a range of 2a or more and 8a or less, where a is the amount of the fine particles that can be arranged in the partition wall in a plan view. 18. The electrophoretic display device according to 18. Forming a first partition wall partitioning a plurality of pixel regions on the first substrate, and forming the second partition wall corresponding to the first partition wall on a second substrate;
Forming a first engagement portion on an upper surface of the first partition wall portion and forming a second engagement portion corresponding to the first engagement portion on an upper surface of the second partition wall portion;
Forming a reflecting portion on at least one of the first engaging portion and the second engaging portion;
Forming a partition wall by combining the first partition wall portion and the second partition wall portion so that the first engagement portion and the second engagement portion face each other;
Bonding the partition on the first substrate;
Filling an electrophoretic material into a cell surrounded by at least the partition and the first substrate;
And a step of bonding a second substrate on the first substrate through the partition wall. A method for manufacturing an electrophoretic display device. The first engagement portion has a convex shape and the second engagement portion has a concave shape,
The first partition wall portion is bonded to the first substrate with the convex first engaging portion facing away from the first substrate when the partition wall is bonded onto the first substrate. 22. A method for producing an electrophoretic display device according to item 21.

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