JP5477124B2 - Electrophoretic display device, electronic apparatus and electrophoretic display body - Google Patents

Description

  The present invention relates to an electrophoretic display technology.

When an electric field is applied to a dispersion liquid (also referred to as “dispersion system”) in which charged particles are dispersed in a solvent (dispersion medium), the particles move (migrate) in the dispersion medium by Coulomb force. This phenomenon is called electrophoresis, and an electrophoretic display (EPD) that displays desired information such as an image using the electrophoresis is known.
As a configuration example of EPD, for example, as shown in Patent Document 1 below, a pair of substrates is partitioned into a plurality of spaces (cells) by partition walls, and charged particles (electrophoretic particles) are contained in each cell. ) And a dispersion system containing a dispersion medium is known.

JP 2004-4773 A

  One cell of EPD can correspond to one pixel (pixel), and full color display is possible by associating three different colors (for example, red, green, and blue) with three cells. Examples of the cell configuration include (1) when white particles, black particles, and color dispersion are filled, (2) when white particles, black particles, and color particles are filled, and (3) white particles and black particles. And a color filter is attached.

  In the cell configurations of (1) and (2) above, when it is desired to display red, the two green and blue pixels other than the pixel displaying red are controlled to be in a white or black display state, respectively. That is, the display state of the three pixels is any one of (red, white, white), (red, white, black), (red, black, black). Similarly, when displaying green or blue, the two pixels other than the target color (single color) to be displayed are controlled to display in white or black, respectively.

That is, even if any one of the three primary colors (red, green, and blue) is displayed, the target color cannot be displayed with all of the three color areas (3 pixels). Only one third of the color area of three colors (three pixels), that is, one pixel can actually display the target color.
One of the objects of the present invention is to improve the display performance of an electrophoretic display device, for example, the efficiency and saturation of monochromatic display.
In addition, the present invention is not limited to the above-described object, and other effects of the present invention can be achieved by the functions and effects derived from the respective configurations shown in the embodiments for carrying out the present invention, which cannot be obtained by conventional techniques. It can be positioned as one of

[Mode 1] In order to achieve the above object, an electrophoretic display device of mode 1 includes a substrate,
A plurality of cells formed by spatially partitioning one surface of the substrate with a plurality of light-transmitting partitions;
A first electrode having a transparent electrode surface provided on the opening side of each of the cells and serving as a display surface in plan view from the viewing side;
A second electrode provided on the bottom side of each cell and having an electrode surface facing the bottom surface of each cell;
A dispersion medium having transparency and insulation provided inside each of the cells;
At least one kind of colored electrophoretic particles charged in a predetermined polarity, dispersed in the dispersion medium of each cell and colored in a different color from the adjacent cells;
Reflecting the light transmitted through the first electrode from the viewing side provided on the inner side of each cell, the reflected light is incident on an adjacent cell through the partition wall, and from the adjacent cell A reflecting member having a reflecting portion for reflecting the light incident through the partition wall and causing the reflected light to enter the first electrode of the cell;
Voltage applying means for applying a voltage of a predetermined polarity to the first electrode and the second electrode.

  In such a configuration, for example, in the first cell, it is assumed that the first electrophoretic particles colored in the first color are collected on the first electrode. In this case, the light incident on the first cell from the viewing side passes through the first electrophoretic particles, and is then reflected by the reflecting member inside the first cell. The reflected light becomes the first colored light that is the color light of the first color and enters the adjacent second cell, and the incident first colored light is reflected by the reflecting member of the second cell. . At this time, in the second cell, it is assumed that second electrophoretic particles colored in a second color different from the first color are gathered in the first electrode. In this case, the first colored light reflected by the reflecting member in the second cell passes through the second electrophoretic particles from the inside of the cell and travels to the viewing side via the first electrode of the second cell. Emitted.

  On the other hand, the light that has entered the second cell from the viewing side passes through the second electrophoretic particles, and is then reflected by the reflecting member inside the second cell. The reflected light becomes the second colored light that is the color light of the second color and enters the adjacent first cell, and the incident second colored light is reflected by the reflecting member of the first cell. . The second colored light reflected by the reflecting member in the first cell passes through the first electrophoretic particles from the inside of the cell and is emitted to the viewing side through the first electrode of the first cell.

  Thereby, the colored light observed on the viewer side is reflected on the first color reflected light of the first electrophoretic particles gathered on the first electrode of the first cell and on the first electrode of the second cell. The mixed color light resulting from the fact that both cells are adjacent to the reflected light of the second color of the aggregated second electrophoretic particles is included. In addition, the first color mixing light by the color mixing when the first colored light incident on the second cell from the first cell passes through the second electrophoretic particles in the second cell is included. Furthermore, the second color mixing light by the color mixing when the second colored light incident on the first cell from the second cell passes through the first electrophoretic particles in the first cell is included.

Here, in the first and second cells adjacent to each other, the first colored light of the first cell and the second colored light of the second cell are mixed by the juxtaposition of the cells (hereinafter, juxtaposed mixed color). The two are added and mixed. On the other hand, the first mixed color light and the second mixed color light are the same as the mixed color when the two color particles are stacked (hereinafter referred to as stacked mixed color), and the first colored light and the second mixed light are the same. Color mixing is performed by integrating with colored light. Then, the mixed color light obtained by adding the mixed color light by juxtaposition, the first mixed color light, and the second mixed color light becomes the final observation light.
In other words, the observation light is obtained by adding the first mixed color light and the second mixed color light by the layered mixed color to the mixed color light of the first color light and the second color light by the juxtaposed mixed color. .

  Accordingly, when performing mixed color display, it is possible to generate a stacked color mixture in each cell as compared with the case where only a conventional mixed color display is used, so that, for example, the juxtaposition is performed because the cell size is large. Even when color mixing is difficult to occur, the saturation of the display color (mixed color) can be increased. In addition, since mixed color display with adjacent pixels can be performed, one display color can be expressed by a plurality of cells.

[Embodiment 2] Furthermore, the electrophoretic display device of embodiment 2 is the electrophoretic display device of embodiment 1, wherein each adjacent three cells in the plurality of cells constitute one pixel,
Each of the three cells as the first to third cells,
Inside the first cell, as the colored electrophoretic particles, the first electrophoretic particles colored in red and charged in opposite polarities are colored in a cyan color that is complementary to the red color. Second electrophoretic particles
Inside the second cell, the colored electrophoretic particles are colored in a magenta color having a complementary color relationship with the third electrophoretic particles colored in green and charged in opposite polarities. A fourth electrophoretic particle,
Inside the third cell, as the colored electrophoretic particles, the fifth electrophoretic particles colored in blue and charged in opposite polarities are colored yellow that is complementary to the blue color. And sixth electrophoretic particles.

  In such a configuration, the red color of the first electrophoretic particle in the first cell is the magenta color of the fourth electrophoretic particle in the second cell and the sixth electrophoretic particle in the third cell. It can be expressed by a mixed color with yellow. The green color of the third electrophoretic particles in the second cell is a color mixture of the cyan color of the second electrophoretic particles in the first cell and the yellow color of the sixth electrophoretic particles in the third cell. Can be expressed by The blue color of the fifth electrophoretic particle in the third cell is a color mixture of the cyan color of the second electrophoretic particle in the first cell and the magenta color of the fourth electrophoretic particle in the second cell. Can be expressed by

  Thus, for example, the first electrophoretic particles are aggregated on the first electrode in the first cell, the fourth electrophoretic particles are aggregated on the first electrode in the second cell, and the sixth cell is in the third cell. It is assumed that the electrophoretic particles are assembled on the first electrode. In this case, first, red light is formed by color mixture by juxtaposition of the second cell and the third cell. In addition, the cyan light reflected by the reflecting member of the second cell and incident on the third cell is reflected by the reflecting member of the third cell, passes through the sixth electrophoretic particles, and passes through the third cell. The light is emitted through the first electrode. Further, the magenta light reflected by the reflecting member of the third cell and incident on the second cell is reflected by the reflecting member of the second cell, passes through the fourth electrophoretic particles, and passes through the second electrophoretic particles. The light is emitted from one electrode. That is, red light in which cyan light and magenta light are mixed is emitted from the second cell and the third cell due to the mixed color mixture.

  As a result, the observation light when the pixel composed of the first to third cells is viewed from the viewing side includes the red light of the first cell, the magenta light of the second cell, and the yellow light of the third cell. It includes red light obtained by adding together red light by juxtaposed color mixing, red light that is mixed and mixed in the second cell, and red light that is mixed and mixed in the third cell. Strictly speaking, color light and the like mixed in the first cell are also included.

  That is, the red color can be displayed by three cells, and the mixed color mixture is included in comparison with the mixed color only by juxtaposition. For example, the juxtaposed color mixture hardly occurs due to a large cell size or the like. Even in this case, red display with relatively high saturation can be performed. Therefore, display of any one of red, green, and blue having relatively high saturation can be performed by the first to third cells.

[Mode 3] Furthermore, the electrophoretic display device according to mode 3 is the electrophoretic display device according to mode 1 or 2, wherein the reflecting member is uncharged or colored electrophoretic having a size larger than the colored electrophoretic particles. White particles having a smaller charge amount than the particles.
With such a configuration, in each pixel, colored electrophoretic particles are gathered on the lower electrode, whereby white display can be performed with uncharged or minutely charged white particles.
In addition, since the white particles themselves serve as a reflecting member, the light transmitted through the colored electrophoretic particles assembled on the first electrode can be reflected and incident on an adjacent cell. The same operation and effect as can be obtained.

[Embodiment 4] Furthermore, the electrophoretic display device of embodiment 4 is the electrophoretic display device of embodiment 3, wherein the white particles as the reflection member are fixedly provided inside the cell.
Since the white particles are fixed in the cell, the control of the migration of the colored electrophoretic particles can be simplified as compared with the case where the white particles are not fixed.
[Embodiment 5] Furthermore, the electrophoretic display device according to Embodiment 5 is the electrophoretic display device according to any one of Embodiments 1 to 4, wherein the reflection member is concealed so as to conceal the lower electrode in plan view from the viewing side. Provided.
With such a configuration, when performing white display, it is possible to prevent the color of the colored electrophoretic particles assembled on the lower electrode from being viewed from the viewing side.

[Mode 6] Further, the electrophoretic display device according to mode 6 is the electrophoretic display device according to mode 5, and does not hinder the migration of the colored electrophoretic particles in a plan view from the viewing side inside each cell. In a range, a single white particle having a size capable of concealing the lower electrode or a plurality of white particles having a number capable of concealing the lower electrode were disposed.
With such a configuration, when performing white display, it is possible to prevent the color of the colored electrophoretic particles assembled on the lower electrode from being viewed from the viewing side.
[Mode 7] On the other hand, in order to achieve the above object, an electronic apparatus according to mode 7 includes the electrophoretic display device according to any one of modes 1 to 6.
With such a configuration, the same operation and effect as the electrophoretic display device according to any one of Embodiments 1 to 6 can be obtained.

[Embodiment 8] In order to achieve the above object, the electrophoretic display of Embodiment 8 includes a substrate,
A plurality of cells formed by spatially partitioning one surface of the substrate with a plurality of light-transmitting partitions;
A first electrode having a transparent electrode surface provided on the opening side of each of the cells and serving as a display surface in plan view from the viewing side;
A second electrode provided on the bottom side of each cell and having an electrode surface facing the bottom surface of each cell;
A dispersion medium having transparency and insulation provided inside each of the cells;
At least one kind of colored electrophoretic particles charged in a predetermined polarity, dispersed in the dispersion medium of each cell and colored in a different color from the adjacent cells;
Reflecting the light transmitted through the first electrode from the viewing side provided on the inner side of each cell, the reflected light is incident on an adjacent cell through the partition wall, and from the adjacent cell A reflecting member having a reflecting portion that reflects light incident through the partition wall and causes the reflected light to enter the first electrode of the cell.
With such a configuration, the same operations and effects as those of the electrophoresis apparatus of the first aspect can be obtained.

1 is an exploded perspective view schematically showing an electrophoretic display device 1 according to an embodiment. FIG. 2 is a schematic partial cross-sectional view of the electrophoretic display device 1 illustrated in FIG. 1. 3 is a plan view showing an example of electrode shape and arrangement of the electrophoretic display device 1. FIG. (A) is the fragmentary sectional view which shows typically the example of a combination of the color particle in the cell 6, (b) is the figure which listed the example of the combination of the color in (a). (A)-(c) is a top view which shows the example of arrangement | positioning structure of the 1st-3rd cell 6 (# 1- # 3). (A)-(c) is typical fragmentary sectional drawing of the electrophoretic display device which illustrated the mechanism of the color mixture by three sub pixels. It is a figure which shows the example of a combination of the display color of cell # 1-cell # 3. It is a figure which shows an example of the pattern of voltage polarity in the case of 4 electrode structure. (A) And (b) is a figure which shows the example of a notation of the electrode in the case of 4 electrode structure and 3 electrode structure. It is a typical fragmentary sectional view of an electrophoretic display device which shows an example of the voltage polarity of each electrode in the case of performing red display in a 4 electrode structure. It is a typical fragmentary sectional view of the electrophoretic display device which shows an example of the voltage polarity of each electrode in the case of performing white display in a 4 electrode structure. It is a typical fragmentary sectional view of the electrophoretic display device which shows an example of the voltage polarity of each electrode in the case of performing black display in a 4 electrode structure. It is a figure which shows an example of the pattern of the voltage polarity in the case of a 3 electrode structure. It is a typical fragmentary sectional view of the electrophoretic display device which shows an example of the voltage polarity of each electrode in the case of performing red display in a 3 electrode structure. It is a typical fragmentary sectional view of the electrophoretic display device which shows an example of the voltage polarity of each electrode in the case of performing white display in a 3 electrode structure. (A)-(d) is a figure which shows an example of the fixing method to the bottom face part of the cell 6 of the white large particle 5C. (A)-(c) is a typical top view which shows the example of arrangement | positioning structure in the cell 6 of the white large particle 5C. (A) is an xy chromaticity diagram created using measured values measured by the electrophoretic display devices of the present embodiment and comparative examples, and (b) is an xy chromaticity diagram of the present invention and comparative examples. It is a figure which shows the measured value used for. FIG. 10 is a schematic partial cross-sectional view illustrating a structure of an electrophoretic display device according to Modification 1.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIGS. 1-19 is a figure which shows embodiment of the electrophoretic display apparatus which concerns on this invention, an electronic device, and an electrophoretic display body.
However, the embodiment described below is merely an example, and there is no intention to exclude various modifications and technical applications that are not explicitly described below. That is, the present invention can be implemented with various modifications without departing from the spirit of the present invention. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. The drawings are schematic and do not necessarily match actual dimensions and ratios. In some cases, the dimensional relationships and ratios may be different between the drawings.

(One embodiment)
1 is an exploded perspective view schematically illustrating an electrophoretic display device 1 according to an embodiment, FIG. 2 is a schematic partial cross-sectional view of the electrophoretic display device 1 illustrated in FIG. 1, and FIG. 3 is a plan view illustrating an example of an electrode shape and arrangement of the display device 1. FIG. 2 represents the viewing direction of the observer of the electrophoretic display device 1, and FIG. 3 corresponds to a plan view of the viewing direction 100 in plan view.
As shown in FIGS. 1 and 2, the electrophoretic display device 1 of the present embodiment exemplarily includes a substrate 3 and a plurality of recesses spatially partitioned by a plurality of partition walls 30 on one surface of the substrate 3. 31 and the substrate 4 bonded to each partition wall 30 so as to close the opening of each recess 31.

  The partition wall 30 can be obtained, for example, by forming a predetermined pattern wall (projection) on one surface of the substrate 3. As an example of a method for forming such a convex portion, an inkjet method (droplet discharge method), a screen printing method, a gravure printing method, a printing method such as a nanoimprinting method, a photolithography method, or the like can be given. As another example, after a layer of a material forming a convex portion is formed on the substrate 3, this layer is mechanically, physically or chemically etched according to a predetermined pattern, or laser processing, embossing processing, etc. The partition wall 30 can also be formed by machining, blasting, or the like.

  The material of the partition wall 30 may be any material that transmits light, and exemplarily includes various resin materials such as an epoxy resin, an acrylic resin, a urethane resin, a melamine resin, and a phenol resin. One or more selected from these can be used in combination. As a non-limiting example, a permanent photoresist TMMR S2000 for MEMS manufactured by Tokyo Ohka Kogyo Co., Ltd. can be used. The average height of the partition walls 30 in the direction perpendicular to the substrate 3, in other words, the distance between the substrates 3 and 4 can be set to about 10 to 500 μm as a non-limiting example.

Further, as the material of the partition wall 30, it is preferable to use a material having a transmittance of 0.6 or more in the visible light wavelength region at a thickness of 100 μm, and more preferably a material having a transmittance of 0.75 or more. .
The closed space 6 formed by the inner wall of the recess 31 and the substrate 4 is called a cell. In each cell 6, the electrophoretic particles 5A to 5B are dispersed (suspended) in a predetermined solvent (dispersion medium). A solution (dispersion) 5 is enclosed. The dispersion of the electrophoretic particles 5A to 5B in the dispersion medium is performed by, for example, one or more of paint shaker method, ball mill method, media mill method, ultrasonic dispersion method, stirring dispersion method, and the like. be able to.

One cell 6 can correspond to one picture element (pixel) or one sub-pixel. For example, in the case of performing full-color display, each of the three cells 6 serves as a sub-pixel, and one cell 3 corresponds to one sub-pixel. A pixel (pixel) can be configured, and each cell 6 can correspond to one of three different colors. As the three different colors, three additive primary colors (red, green, and blue), or three subtractive primary colors (cyan, magenta, and yellow) that are complementary to the three primary colors can be used.
The shape of the cell 6 in plan view in the viewing direction 100 can be illustratively a triangle, a quadrangle, a hexagon, a circle, an ellipse, or the like. If the cell 6 has a hexagonal shape and the cell pattern has a honeycomb shape, the mechanical strength of the display unit (electrophoretic display 2) can be improved.

In addition, two electrodes 81 and 82 are provided per cell on the other surface side of the substrate 3 (the side opposite to the viewing direction 100), and one cell is provided on the side viewed from the viewing direction 100 of the substrate 4. Two electrodes 71 and 72 are provided. That is, a total of four electrodes 71, 72, 81 and 82 are provided in one cell 6.
For convenience, the first and second electrodes 71 and 72 viewed from the viewing direction 100 in FIG. 2 are “surface electrodes”, and the third and fourth electrodes 81 and 82 on the opposite side of the viewing direction 100 are “ Sometimes referred to as a “back electrode”. The front surface electrodes 71 and 72 form the first electrode portion 70, and the back surface electrodes 81 and 82 form the second electrode portion 80 that faces the first electrode portion 70 with the cell 6 interposed in the viewing direction 100. It is made.

Furthermore, as shown in FIG. 2, each cell 6 has white particles 5C (hereinafter referred to as white large particles 5C), which are electrophoretic particles colored white, which are larger in size than the particles 5A to 5B. Is enclosed.
The shape of the white large particles 5C is an oval shape in the example shown in FIG. 2, and the short and long diameters of the white large particles 5C are lower than the white large particles 5C when viewed from the viewing direction 100. The size is hidden.

The substrate 3, the substrate 4, the cell 6, and the electrodes 71, 72, 81, and 82 constitute the electrophoretic display body 2 that functions as a display unit of the electrophoretic display device 1. The electrophoretic display body 2 is a concept including, for example, an EPD panel and an EPD sheet.
For the substrate 4 and the surface electrodes 71 and 72 that are viewed from the viewing direction 100, a transparent substrate and a transparent electrode that transmit light in the visible light wavelength region are used so that the inside of the cell 6 corresponding to the pixel can be viewed. it can.

  As a material for the transparent substrate and the transparent electrode, a material having conductivity is sufficient. Non-limiting examples include metal materials such as copper, aluminum or alloys containing these, carbon-based materials such as carbon black, electronically conductive polymer materials such as polyacetylene, polypyrrole, or derivatives thereof, polyvinyl alcohol, polycarbonate Ionic conductive polymer material in which ionic substances such as NaCl, LiClO4, KCl, LiBr, LiNO3, LiSCN are dispersed in a matrix resin such as polyethylene oxide, indium tin oxide (ITO), fluorine-doped tin oxide Various conductive materials such as conductive oxide materials such as materials (FTO), tin oxide (SnO2), and indium oxide (IO) are used, and one or more of these are used in combination. be able to. As a non-limiting example of the transparent electrode, Toray's PET / ITO sheet NXC1 can be used. Note that the electrodes 81 and 82 can be made of the same material as described above.

  The back electrodes 81 and 82 may be formed on one surface of the circuit board 9. In addition to the back electrodes 81 and 82, the circuit board 9 includes, for example, a thin film transistor (TFT) that functions as a switching element, a control circuit 91 that controls a voltage applied to the electrodes 71, 72, 81, and 82, and the like. An electric circuit (not shown) is provided. The control circuit 91 is electrically connected to the electrodes 71, 72, 81, and 82, and can individually control the magnitude and polarity (positive / negative) of the voltage applied to each.

  Each of the substrate 3, the substrate 4, and the partition wall 30 has, for example, electrical insulation and impermeability (retainability) of the dispersion liquid sealed in the cell 6. For the substrate 3, the substrate 4, and the partition wall 30, for example, a glass substrate may be used, or a flexible sheet-like member may be used. If a flexible sheet-like member is used for the substrates 3 and 4, a deformable display unit such as an electronic paper can be obtained. Examples of the material for the sheet-like member having flexibility include polyolefins, liquid crystal polymers, thermoplastic elastomers, and the like, and copolymers, blends, polymer alloys, and the like mainly containing them. A seed or a mixture of two or more can be used. The thickness of the sheet-like member can be appropriately set while achieving harmony between flexibility and strength as an EPD, and can be about 20 to 500 μm as a non-limiting example.

(Electrode shape and arrangement)
The surface electrodes 71 and 72 on the substrate 4 side correspond to each region when the area of the rectangular cell 6 is divided into two in a plan view as viewed from the viewing direction 100 as illustrated in FIG. Can be provided. Similarly, the back surface electrodes 81 and 82 on the substrate 3 side can be provided corresponding to each region when the area of the rectangular cell 6 is divided into two in a plan view as viewed from the circuit substrate 9 side. However, some or all of the areas (sizes) of the electrodes 71, 72, 81, and 82 may be equal to or different from each other.

In addition, the shape and arrangement of the electrodes 71, 72, 81, and 82 are not limited to the shape and arrangement shown in FIG. For example, it is good also as a shape and arrangement | positioning as shown in FIG.3 (b) or FIG.3 (c). 3 (b) and 3 (c) are schematic partial plan views of the electrophoretic display device 1 corresponding to FIG. 3 (a).
In the example shown in FIG. 3B, the surface electrode 71 is provided so as to extend annularly along the peripheral region of the cell 6 in a plan view in the viewing direction 100, and the cell 6 surrounded by the annular surface electrode 71. This is an example in which the surface electrode 72 is provided in the central region. For example, the back electrodes 81 and 82 on the substrate 3 side can also have the same shape and arrangement as the front electrodes 71 and 72 facing each other across the cell 6.

  That is, when the electrophoretic display 2 is viewed from the circuit board 9 side, the back electrode 81 can be provided so as to extend in a ring shape along the peripheral region of the cell 6, and the back electrode 82 is formed in the ring shape. It can be provided in the central region of the cell 6 surrounded by the electrode 81. However, the shape (including size) and arrangement of the electrode 71 and the electrode 81 (electrode 72 and electrode 82) may not be the same.

  On the other hand, in the example shown in FIG. 3C, the band-shaped surface electrode 71 having a certain width and extending along each side on the two opposite sides of the rectangular cell 6 in a plan view in the viewing direction 100. And a band-shaped surface electrode 72 having a certain width and extending in parallel with the electrode 71 is provided in a region sandwiched between the electrodes 71. The back electrodes 81 and 82 on the substrate 3 side can also have the same shape and arrangement as the front electrodes 71 and 72. The width (area) of the electrode 72 (82) can be set larger than the width (area) of the electrode 71 (81) as illustrated in FIG. However, it is not limited to this.

  3A to 3C, the front surface electrodes 71 and 72 and the back surface electrodes 81 and 82 are spatially separated from each other and electrically insulated. Each of the electrodes 71, 72, 81 and 82 is individually (independently) controlled by the control circuit 91 described above. The voltage control includes control of the magnitude and polarity (positive / negative) of the applied voltage.

By controlling the magnitude of the applied voltage, the migration speed of the electrophoretic particles in the cell 6 shown in FIG. 2 can be controlled. In addition, by controlling the polarity of the applied voltage, the electrophoretic particles in the cell 6 are unevenly distributed on the substrate 4 side which is the viewing side, or conversely on the substrate 3 side which is the opposite side to the viewing side. Can be.
Further, in the electrode shapes and arrangements exemplified in FIGS. 3A to 3C, the polarity of the electrophoretic particles is controlled by controlling the pattern of voltage polarity (positive / negative) applied to each of the electrodes 71, 72, 81 and 82. It is also possible to bias the migration path of the particles to different regions in the cell 6 according to (positive or negative charge).

(Dispersion)
Next, the dispersion liquid 5 sealed in the cell 6 will be described.
FIG. 4 is a partial cross-sectional view schematically showing a combination example of the color particles in the cell 6.
A cell 6 shown in FIG. 4 is filled and sealed with a solution (dispersion) 5 in which electrophoretic particles (5A to 5B in the example of FIG. 2) are dispersed (suspended) in a predetermined solvent (dispersion medium). Yes. As an example of a method of filling the dispersion liquid 5 into the cell 6 (recess 31), a method of dipping the substrate 3 having the recess 31 in the dispersion 5, a dropping method using a dispenser, an ink jet method (droplet discharge method) And various coating methods such as spin coating, dip coating, and spray coating. If the dropping method or the ink jet method is used, the dispersion 5 can be selectively supplied to the target cell 6. Therefore, the dispersion 5 can be reliably supplied into the cell 6 without waste. The direction in which the dispersion 5 is supplied to the cell 6 is not necessarily limited to the vertically downward direction. It can also be supplied laterally or vertically upward.

  Examples of the dispersion medium include cellosolves such as methyl cellosolve, esters such as methyl acetate, ketones such as acetone, aliphatic hydrocarbons such as pentane (liquid paraffin), and alicyclic hydrocarbons such as cyclohexane, Aromatic hydrocarbons such as benzene, halogenated hydrocarbons such as methylene chloride, aromatic polycyclic rings such as pyridine, nitriles such as acetonitrile, amides such as N, N-dimethylformamide, carboxylates or Various other oils can be mentioned, and these can be used alone or as a mixture.

Especially, as a dispersion medium, what has aliphatic hydrocarbons (liquid paraffin) as a main component is preferable. A dispersion medium containing liquid paraffin as a main component is preferable because it has a relatively high aggregation suppressing effect on electrophoretic particles and a relatively low affinity (solubility) with the constituent materials of the cell 6. Thereby, it can prevent or suppress that the display performance of EPD deteriorates with time. In addition, liquid paraffin is preferable because it does not have an unsaturated bond and has excellent weather resistance and high safety.
In addition, in the dispersion medium, for example, an electrolyte, a surfactant (anionic or cationic) such as an alkenyl succinate, a metal soap, a resin material, a rubber material, an oil, a varnish, a compound Various additives such as a charge control agent comprising particles such as a dispersant, a dispersant such as a silane coupling agent, a lubricant, and a stabilizer may be added.

(Electrophoretic particles)
A plurality of types of electrophoretic particles can be contained in the dispersion liquid 5. FIG. 2 illustrates a state where three types of particles 5A, 5B, and 5C are contained in the dispersion 5.
As said particle | grains 5A-5C, at least 1 sort (s) of a pigment particle, a resin particle, or these composite particles can be used exemplarily.
Examples of pigments constituting the pigment particles include black pigments such as aniline black and carbon black, white pigments such as titanium oxide and antimony oxide, azo pigments such as monoazo, disazo and polyazo, isoindolinone, yellow lead, yellow Examples include yellow pigments such as iron oxide, red pigments such as quinacridone red and chrome vermilion, blue pigments such as phthalocyanine blue and indanthrene blue, and green pigments such as phthalocyanine green. They can be used in combination.

  For example, carbon black, spirit black, lamp black (CI No. 77266), magnetite, titanium black, yellow lead, cadmium yellow, mineral fast yellow, navel yellow, naphthol yellow S, Hansa yellow G, permanent yellow NCG, Chrome yellow, benzidine yellow, quinoline yellow, tartrazine lake, red mouth yellow lead, molybdenum orange, permanent orange GTR, pyrazolone orange, benzidine orange G, cadmium red, permanent red 4R, watching red calcium salt, eosin lake, brilliant carmine 3B , Manganese purple, fast violet B, methyl violet lake, bitumen, cobalt blue, alkali blue lake, victoria -Lake, First Sky Blue, Indanthrene Blue BC, Ultramarine, Aniline Blue, Phthalocyanine Blue, Calco Oil Blue, Chrome Green, Chrome Oxide, Pigment Green B, Malachite Green Lake, Phthalocyanine Green, Final Yellow Green G, Rhodamine 6G, Quinacridone Rose Bengal (C.I. No. 45432), C.I. I. Direct Red 1, C.I. I. Direct Red 4, C.I. I. Acid Red 1, C.I. I. Basic Red 1, C.I. I. Modern Tread 30, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 184, C.I. I. Direct Blue 1, C.I. I. Direct Blue 2, C.I. I. Acid Blue 9, C.I. I. Acid Blue 15, C.I. I. Basic Blue 3, C.I. I. Basic Blue 5, C.I. I. Modern Blue 7, C.I. I. Pigment blue 15: 1, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 5: 1, C.I. I. Direct Green 6, C.I. I. Basic Green 4, C.I. I. Basic Green 6, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 180, C.I. I. Pigment yellow 162, nigrosine dye (CI No. 50415B), metal complex dye, silica, aluminum oxide, magnetite, maghemite, various ferrites, cupric oxide, nickel oxide, zinc oxide, zirconium oxide, titanium oxide, Examples thereof include metal oxides such as magnesium oxide and magnetic materials containing magnetic metals such as Fe, Co, and Ni, and one or more of these can be used in combination.

Examples of the resin material constituting the resin particles include acrylic resin, urethane resin, urea resin, epoxy resin, polystyrene, polyester, and the like, and one or more of these are combined. Can be used. 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 of pigment and resin material mixed in an appropriate composition ratio. And the like. These particles have the advantage that they are easy to manufacture and the charge can be controlled relatively easily.
Examples of particles obtained by coating the surface of pigment particles with other pigments include those obtained by coating the surface of titanium oxide particles with silicon oxide or aluminum oxide. Such particles may be used as white particles. it can. Further, the carbon black particles or the particles covering the surface thereof can be used as colored particles (black particles).

  Further, a polymer having high compatibility with the dispersion medium may be physically adsorbed or chemically bonded to the surfaces of the particles 5A to 5B. By doing in this way, the dispersibility in the dispersion liquid 5 of particle | grains 5A-5B can be improved. Among these, the polymer is preferably chemically bonded from the viewpoint of release from the particle surface. Such binding acts in a direction that reduces the apparent specific gravity of the particles 5A to 5B, thereby improving the affinity of the particles 5A to 5B in the dispersion medium, that is, dispersibility.

  Examples of the polymer include, for example, a polymer having a group reactive with the electrophoretic particle and a chargeable functional group, a group reactive with the electrophoretic particle and a long alkyl chain, a long ethylene oxide chain, and a long chain. A polymer having a fluorinated alkyl chain, a long dimethylsilicone chain, and the like, and a group reactive with electrophoretic particles, a chargeable functional group, a long alkyl chain, a long ethylene oxide chain, a long fluorinated alkyl chain, Examples thereof include a polymer having a long chain dimethyl silicone chain.

In such a polymer, examples of groups (reactive groups) having reactivity with the particles 5A to 5B include epoxy groups, thioepoxy groups, alkoxysilane groups, silanol groups, alkylamide groups, aziridine groups, oxazone groups, And one or more of them can be appropriately selected according to the type of the particles 5A to 5B.
The average particle diameter of the particles 5A to 5B is appropriately selected, for example, within a range in which a sufficient hiding ratio (display contrast) is obtained in the visible light range, and the particles 5A to 5B are easily settled and display quality is not deteriorated. be able to. The average particle diameter of the particles 5A to 5B satisfying such a range is about 0.1 to 10 μm as a non-limiting example.

On the other hand, the particle size of the white large particles 5C is particularly true when the number of particles is singular and the cross section of the partition wall 30 of the cell 6 is a perfect sphere having a perfect circle (illustrated in FIG. 4). A particle size having a length of about 80% of the height can be selected. However, an elliptical sphere having an elliptical cross section can be selected according to the shape of the cell 6 and the positions where the back electrodes 81 and 82 are disposed.
In particular, as illustrated in FIG. 2, when the length of the cell 6 in the width direction (direction perpendicular to the viewing direction) is longer than the length in the height direction of the partition wall, The area can be expanded in the width direction by selecting an elliptical sphere having a major axis in the direction. Furthermore, since the area that can be concealed is increased by increasing the area in the width direction, the area of the back electrode can be increased. However, in order to reflect incident light in a target direction, it is necessary to configure the spherical surface to have a certain reflection angle. There is a need to.

Furthermore, the particles 5A and 5B can be charged particles having opposite polarities. Illustratively, the particle 5A is a positively charged particle charged positively (+), and the particle 5B is a negatively charged particle charged negatively (−).
On the other hand, the white large particles 5C are weakly charged particles having a charge amount sufficiently smaller than the charge amount per one of the particles 5A and 5B, or non-charged particles having substantially no polarity.
Here, FIGS. 17A to 17C are schematic plan views showing arrangement examples of the white large particles 5 </ b> C in the cell 6. FIGS. 17A to 17C are plan views when observed from the viewing direction 100.

Further, in the present embodiment, in the case of a single large white particle 5C, for example, as shown in FIG. 17 (a), the back electrodes 81 and 82 are covered in a plan view on the bottom surface inside each cell 6. It is fixedly arranged with an adhesive or the like at a position where it can be formed.
In this case, the white large particles 5C are not affected by the electric field applied by the electrodes 71, 72, 81, and 82, or even if they are received, the white large particles 5C do not move through the solvent because they are fixedly arranged.

Further, when two white large particles 5C are arranged inside each cell 6, for example, as shown in FIG. 17 (b), the white large particles 5C are made into an elliptical sphere according to the shape and arrangement position of the electrodes, The rear electrodes 81 and 82 are fixedly arranged side by side at a position where they can be covered in a plan view.
When four large white particles 5C are arranged inside each cell 6, for example, as shown in FIG. 17 (c), the large white particles 5C are matched to the shape and arrangement position of the electrodes. It is a spherical shape, and is arranged and fixed in a position where it can cover the back electrodes 81 and 82 in a plan view.
In each of the above examples, the configuration in which the white large particles 5C are fixed inside the cell 6 has been described. However, the present invention is not limited to this configuration, and the white large particles 5C may not be fixed in the cell 6.

Further, the arrangement configuration of the white large particles 5C is not limited to the example shown in FIG. 17, and another arrangement configuration including the number of the white large particles 5C may be employed.
The back electrodes 81 and 82 are desirably covered with the large white particles 5C when viewed in plan from the viewing direction 100. However, since the large white particles 5C are spherical and need to secure a space in which the colored particles 5A and 5B can be unevenly distributed near the upper portions of the back electrodes 81 and 82 inside the cell 6, in fact, all of them are covered. It is difficult to hide.

In addition, it is desirable that the inner bottom surface portion of each cell 6 be white at least a portion that does not overlap with the back electrodes 81 and 82 in plan view from the viewing direction 100. This prevents the color of the bottom surface of the cell 6 from being mixed and lowering the contrast when displaying white.
Since the positively charged particle 5A is a particle having a positive charge, the positively charged particle 5A faces the electrode so as to be adsorbed (attached) to the electrode to which a negative voltage is applied among the four electrodes 71, 72, 81 and 82. Run. Conversely, since the negatively charged particle 5B is a particle having a negative charge, the negatively charged particle 5B faces the electrode so as to be adsorbed to the electrode to which a positive voltage is applied among the four electrodes 71, 72, 81 and 82. Run.
Therefore, by controlling the pattern of the voltage polarity applied to the electrodes 71, 72, 81 and 82, the charged particles 5A and 5B can be made to move from the four electrodes 71, 72, 81 and 82 in the cell 6, respectively. It can be unevenly distributed in the area | region (space) corresponding to either.

  In this way, the electrophoretic display device 1 can change the color in the cell 6 viewed from the viewing direction 100 (hereinafter also referred to as “display color”). In addition, by controlling the voltage polarity pattern, it is also possible to individually control the migration paths in the cells 6 of the particles 5A and 5B charged to opposite polarities. Therefore, when the display color is switched, the charged particles 5A and 5B can be migrated between the substrates 3 and 4 through different paths, and the probability of mutual attachment (coupling) can be reduced.

(Color combination)
The colors of the particles 5A to 5B in one cell 6 can be different from each other. As the colors of the particles 5A to 5B, for example, black or an intermediate color such as white and black (gray) or an additive color mixture of red (R), green (G), and blue (B) 3 Any one of chromatic colors such as the primary colors, three primary colors of the subtractive color mixture of cyan (Cy), magenta (Ma), and yellow (Ye) can be arbitrarily selected.
However, the particle 5C always becomes white (W) in order to play a role as a reflecting member described later.

  For example, the particle 5A is any one of R, G, and B, and the particle 5B is any one of cyan (Cy), magenta (Ma), and yellow (Ye) corresponding to the complementary colors of R, G, and B. Or a combination of one color is possible. Or, conversely, the particle 5A may be any one of cyan (Cy), magenta (Ma), and yellow (Ye), and the particle 5B may be any one of R, G, and B. is there.

In other words, the cell 6 (dispersion 5) can be constituted by a combination of “white large particles 5C + colored particles 5A + complementary colored particles 5B of the colored particles 5A + colorless solvent”. The color particle 5A corresponds to one of the three additive primary colors, and the particle 5B corresponds to one of the three subtractive primary colors that are complementary to the three primary colors.
For example, it is assumed that each cell 6 is a sub-pixel, and that one pixel is configured by each of the three cells 6 (first to third cells 6).

  In this case, in the first cell 6, for example, if “color particle 5A” is a red (R) particle, the complementary color particle of the red particle is a cyan (Cy) particle. , White (W) particles, and dispersion 5 containing red particles, cyan particles, and a colorless solvent are encapsulated. Further, in the second cell 6, for example, if “color particle 5A” is green (G), the complementary color of the green particle is magenta (Ma) particle. , Green particles, magenta particles and a dispersion liquid 5 containing a colorless solvent are encapsulated. Similarly, in the third cell 6, for example, if the “color particle 5 </ b> A” is a blue (B) particle, the complementary color particle of the blue particle is a yellow (Ye) particle. The white particles and the dispersion 5 containing blue particles, yellow particles and a colorless solvent are encapsulated.

  In summary, as the dispersion 5 in the cell 6, three types (combinations) # 1 to # 3 can be selected as illustrated in FIGS. 4 (a) and 4 (b). By controlling the combination of the colors of the particles 5A to 5C viewed from the viewing direction 100 in the cells 6 of these three types of configurations # 1 to # 3, full-color display can be performed on the electrophoretic display body 2. .

(Cell layout)
FIGS. 5A to 5C are plan views showing examples of arrangement configurations of the first to third cells 6 (# 1 to # 3). FIG. 5 is a plan view when viewed from the viewing direction 100.
Hereinafter, regarding the first to third cells 6 constituting one pixel, the configuration of the first cell 6 is # 1, the configuration of the second cell 6 is # 2, and the configuration of the third cell 6 is # 3. The arrangement configuration of these # 1 to # 3 will be described. The first cell 6, the second cell 6, and the third cell 6 are referred to as cell # 1, cell # 2, and cell # 3.

Here, the shape of each cell 6 in plan view is a square, the display color of cell # 1 is red, the display color of cell # 2 is green, and the display color of cell # 3 is blue.
For example, as shown in FIG. 5A, the cells # 1 to # 3 have a cell # 1, a cell # 3, a cell # 2, a cell # 1, a cell # 3, a cell # in the row direction in the first row. It arrange | positions so that it may arrange | position in order of 2, .... Furthermore, the second row is arranged in the order of cell # 2, cell # 1, cell # 3, cell # 2, cell # 1, cell # 3,... In the row direction, and the third row is arranged in the row direction. The cell # 3, the cell # 2, the cell # 1, the cell # 3, the cell # 2, the cell # 1,... Are arranged in this order. The fourth and subsequent lines are repeated from the first line to the third line. That is, it arrange | positions so that the color of particle | grains 5A and 5B of each adjacent cell 6 may mutually differ.

  In addition, for example, as shown in FIG. 5 (b), in the row direction, cell # 1, cell # 3, cell # 2, cell # 1, cell # 3, cell # 2,. -Configured to be arranged in the order of. Furthermore, the second row can be configured to be arranged in the order of cell # 2, cell # 1, cell # 3, cell # 2, cell # 1, cell # 3,. The third and subsequent lines are repeated from the first line to the second line.

  Further, when the shape of each cell 6 in plan view is a hexagon, for example, as shown in FIG. 5C, in the first row, the upper side of the cell # 3 is adjacent to the lower side of the cell # 1, A configuration in which the upper left side of cell # 2 is adjacent to the lower right side of cell # 1 is defined as a unit block, and this unit block is configured to be continuously arranged in a plurality of rows. At this time, the lower left side of cell # 1 of the adjacent unit block is adjacent to the upper right side of cell # 2 of each unit block, and the cell of the adjacent unit block is adjacent to the lower right side of cell # 2 of each unit block. The upper left side of # 3 is adjacent.

Further, the second row is configured such that the unit block in the first row is reversed left and right, and a plurality of unit blocks are continuously arranged in the row direction in this posture. At this time, the upper side of cell # 2 of each unit block in the second row is adjacent to the lower side of cell # 3 in the first row, and the upper side of cell # 1 in each unit block in the second row is cell # 1 in the first row. 2 so as to be adjacent to the lower side.
The third and subsequent lines are repeated from the first line to the second line. At this time, the upper side of the cell # 1 of each unit block in the odd row is adjacent to the lower side of the cell # 2 in the even row, and the upper side of the cell # 2 in each unit block in the odd row is the cell # in the even row. 3 is configured to be adjacent to the lower side.
The arrangement configuration of the cells # 1 to # 3 is not limited to the arrangement configuration shown in FIGS. 5A to 5C, and the cells # 1 to # 3 are adjacent to each other so as to be able to form pixels, and the adjacent cells 6 Other arrangement configurations may be used as long as the colors of the particles 5A and 5B are different from each other.

(Color mixing mechanism)
FIGS. 6A to 6C are schematic partial cross-sectional views of an electrophoretic display device illustrating the mechanism of color mixing using three subpixels. 6A to 6B show an example in which cell # 1, cell # 2, and cell # 3 are arranged in this order.
Here, a cell 6 of a certain configuration #i (i = 1 to 1) is displayed in a single color by the primary color system (red, green or blue) color particles 5A, and the remaining two configurations #j (j = 1) ˜3 and j ≠ i) each cell 6 is set to a single color display by two color particles 5B of a complementary color system (cyan, magenta or yellow) different from the complementary color of the color particle 5A. Alternatively, a cell 6 of a certain configuration #i is displayed in a single color by a color particle 5B of a complementary color system (cyan, magenta or yellow), and the remaining two cells # 6 of the configuration #j are respectively primary color systems (red, green or blue). A single color display using two color particles 5A is used.

In any case, the display colors for the two cells (two subpixels) of the configuration #j are displayed as one color of the primary color system or the complementary color system displayed in one cell 6 of the configuration #i due to the color mixture effect. Is equivalent to Therefore, one of the three additive primary colors (red, green and blue) or the subtractive primary colors (cyan, magenta and yellow) can be displayed with three subpixels.
As an example, as schematically shown in FIGS. 6A to 6C, the cell # 1 is controlled to be displayed in red by the red particles 5A, and the cell # 2 is displayed in magenta color by the magenta particles 5B. In addition, the cell # 3 is controlled to display yellow by the yellow particles 5B. At this time, the mixed color of magenta and yellow is equivalent to displaying red by juxtaposed mixed color when observed from the viewing direction 100.

  Therefore, red can be displayed using the color areas of three cells 6, that is, three subpixels. Similarly, for other colors, it is possible to display a target color using a color area for three subpixels. Specifically, a green color is obtained using a color area corresponding to three subpixels, ie, the green color of the particle 5A of the cell # 2 and the green color of the cyan color of the particle 5B of the cell # 1 and the yellow color of the particle 5B of the cell # 3. Can be displayed. In addition, blue is displayed using a color area corresponding to three subpixels of blue of the particle 5A of the cell # 3 and blue of the cyan color of the particle 5B of the cell # 1 and the magenta color of the particle 5B of the cell # 2. can do.

  In addition, in the configuration of the cell # 1 to cell # 3 of the present embodiment, for example, as shown in FIG. 6A, the incident light L1 incident on the cell # 2 from the viewing direction 100 The magenta particles 5B that are unevenly distributed as display colors near the surface electrodes 71 and 72 are transmitted inside # 2. Then, the incident light L1 transmitted through the magenta color particle 5B becomes magenta color light, travels in the cell # 2, and is reflected by the surface of the white large particle 5C. Since the white large particles 5C of the present embodiment have a spherical shape, the magenta light reflected by the spherical surface (the surface whose reflection angle continuously changes) is scattered. A part of the scattered magenta color light is again transmitted through the magenta color particle 5B in the cell # 2 and emitted toward the viewing side, and the rest enters the adjacent cell # 3.

That is, as shown in FIG. 6A, the remaining magenta light L2 reflected by the spherical surface passes through the partition wall 30 made of a light-transmitting material and enters the adjacent cell # 3.
Next, the magenta light L2 incident on the cell # 3 is reflected (scattered) by the spherical surface of the white large particle 5C of the cell # 3. Part of the reflected magenta color light passes through the yellow color particles 5B that are unevenly distributed as the display color on the surface electrodes 71 and 72 side inside the cell # 3, and is emitted to the viewing side.
Thereby, from the display surface of the cell # 3, the red mixed color light L3 formed by mixing and laminating a part of the magenta light incident from the cell # 2 through the yellow color particle 5B is emitted to the viewing side. The

Further, the magenta color light scattered by the cell # 2 also enters the cell # 1 (not shown), and the magenta color light L2 incident on the cell # 1 is reflected (scattered) by the spherical surface of the white large particle 5C of the cell # 1. ) Part of the reflected magenta color light passes through the red particles 5A that are unevenly distributed as the display color on the surface electrodes 71 and 72 side inside the cell # 1, and is emitted from the display surface to the viewer side.
Thereby, from the display surface of the cell # 1, a part of the magenta color light incident from the cell # 2 passes through the red particles 5B to be mixed and mixed. In this case, the red and magenta are multiplied. Only the red component remains. Therefore, red light is emitted to the viewing side.

  On the other hand, as shown in FIG. 6B, the incident light L1 incident on the cell # 3 from the viewing direction 100 is first unevenly distributed as a display color near the surface electrodes 71 and 72 inside the cell # 3. It passes through the yellow particles 5B. The incident light L1 that has passed through the yellow particles 5B becomes yellow light, travels through the cell # 3, and is reflected by the surface of the white large particles 5C. A part of the reflected yellow light is transmitted again through the yellow particles 5B in the cell # 3 and emitted to the viewing side, and the remaining light enters the adjacent cell # 2.

Next, the yellow light L2 incident on the cell # 2 is reflected (scattered) by the spherical surface of the white large particle 5C of the cell # 2. A part of the reflected yellow light passes through the magenta color particles 5B that are unevenly distributed as the display color on the surface electrodes 71 and 72 inside the cell # 2, and is emitted from the display surface to the viewer side.
Thereby, from the display surface of the cell # 2, red mixed color light L3 formed by mixing and laminating a part of yellow light incident from the cell # 3 through the magenta color particle 5B is emitted to the viewing side. The

  6A and 6B, the incident light L1 incident on the cell # 1 from the viewing direction 100 is unevenly distributed as a display color near the surface electrodes 71 and 72 inside the cell # 1. It passes through the red particles 5A. Then, the incident light L1 transmitted through the red particles 5A becomes red light, travels through the cell # 1, and is reflected (scattered) by the spherical surface of the white large particles 5C. A part of the reflected red light passes through the red particles 5A in the cell # 1 again and is emitted to the viewing side, and the rest enters the adjacent cell # 2 and the like.

The red light incident on the cell # 2 is reflected (scattered) by the spherical surface of the white large particle 5C of the cell # 2. A part of the reflected red light is laminated and mixed by passing through magenta particles 5B that are unevenly distributed as display colors on the surface electrodes 71 and 72 inside the cell # 2, but as described above, the red color is red. Light is emitted to the viewer side.
Here, in the xyz chromaticity diagram (not shown), the red light x, y, z values are Re, the green light x, y, z values are Gr, the blue light x, y, z values are Bu, cyan. Assume that the x, y, and z values of color light are C, the x, y, and z values of magenta light are M, and the x, y, and z values of yellow light are Y.

For example, when 50% of the incident light L1 incident on the cell # 2 is reflected by the spherical surface of the white large particle 5C in the cell # 2 and is incident on the cell # 3, the red mixed color of red emitted from the cell # 3 Since the number of sub-pixels constituting one pixel is 3, light can be expressed as “1/3 × (M / 2 × Y / 2)”.
Similarly, for example, when 50% of the incident light L1 incident on the cell # 3 is reflected by the spherical surface of the white large particle 5C in the cell # 3 and incident on the cell # 2, the red light emitted from the cell # 2 is emitted. Can be expressed as “1/3 × (M / 2 × Y / 2)”.

Further, for example, the remaining 50% of the incident light L1 reflected by the spherical surface in the cell # 2 is emitted from the display surface of the cell # 2 as magenta color light, and the remaining 50% of the incident light L1 reflected by the spherical surface in the cell # 3. % Is emitted from the display surface of the cell # 3 as yellow light. In this case, the color mixture due to the juxtaposition of the cell # 2 and the cell # 3 can be expressed as “1/3 × (M / 2 + Y / 2)”.
For example, when 50% of the incident light L1 incident on the cell # 1 is reflected by the spherical surface of the white large particle 5C in the cell # 1 and enters the cell # 2, the red light emitted from the cell # 2 is emitted. The laminated color mixture light can be expressed as “1/3 × (Re / 2 × M / 2)”.

Also, assuming that the remaining 50% of the incident light L1 reflected by the spherical surface in cell # 1 is emitted as red light from the display surface of cell # 1, this red light is “1/3 × (Re / 2)”. It can be expressed as
From the above, in the cells # 1 to # 3, the display color observed from the viewing direction 100 is “Re / 6 + (2/3 × (2), considering only the target color mixture component in the cells # 2 and # 3. M / 2 + Y / 2)) + (2/3 × (M / 2 × Y / 2)) ”. Note that the second term of the above formula represents the juxtaposed color mixture of M (# 2) and Y (# 3), and the third term represents the stacked color mixture of M and Y.

  As shown in FIG. 6C, when a plurality of white small particles are used instead of the white large particles 5C of the cells # 1 to # 3, the white small particles 5C to the adjacent cells 6 Since the amount of the reflected light is small, the mixed color mixture hardly occurs. Therefore, the display color observed from the viewing direction 100 is “R / 3 + M / 3 + Y / 3” assuming that substantially all of the incident light is emitted from each cell. However, as the cell size increases, juxtaposed color mixing is less likely to occur, and depending on the cell size, the display color may become whitish, and the saturation may decrease.

On the other hand, in the configuration of the present embodiment illustrated in FIGS. 6A to 6B, the red light of the cell # 1, the magenta light of the cell # 2, and the yellow light of the cell # 3 are juxtaposed. The red light can be displayed by the red light obtained by adding together the red light obtained by mixing, the red light formed by mixing and mixing in the cell # 2, and the red light formed by mixing and mixing in the cell # 3.
That is, red can be displayed by the areas of the three cells # 1 to # 3, and also includes a red component due to layered color mixing as compared to color mixing only in juxtaposition. Compared with the configuration, it is possible to perform red display with higher saturation.
This means that if cell # 2 is displayed in green, cell # 1 is displayed in cyan, and cell # 3 is displayed in yellow, cell # 3 is displayed in blue, cell # 1 is displayed in cyan, and cell # 2 is magenta. The same applies to color display.

Also, “cyan (cell # 1) + green (cell # 2) + blue (cell # 3)”, “red (cell # 1) + magenta (cell # 2) + blue (cell # 3)”, Similarly, for the combination of “red (cell # 1) + green (cell # 2) + yellow color (cell # 3)”, the display color of one cell is changed to the side-by-side mixed color and the stacked color mixture in the remaining two cells. Both can be displayed together.
From the above, even when juxtaposed color mixing is difficult to occur due to, for example, a large cell size, color display with relatively high saturation can be performed by each of the three cells # 1 to # 3.

(Voltage polarity pattern)
(4-electrode structure)
FIG. 7 is a diagram illustrating a combination example of display colors of the cell # 1 to the cell # 3. FIG. 8 is a diagram showing an example of a voltage polarity pattern in the case of a four-electrode structure. FIGS. 9A and 9B are diagrams showing examples of electrode notations in the case of a four-electrode structure and a three-electrode structure. 10 to 12 are schematic partial cross-sectional views of the electrophoretic display device showing an example of the voltage polarity of each electrode when red display, white display, and black display are performed.

As shown in FIG. 7, cell # 1 to cell # 3 have white (W), red (R), green (G), blue (B), cyan (Cy), and magenta (Ma) as single display colors. One of eight colors, yellow (Ye) and black (K) is displayed.
In the comparative example in FIG. 7, each of the three cells # 1 to # 3 contains colored particles in a combination of (R, W, K), (G, W, K), (B, W, K). The combination of display colors of individual cells when any of the same eight colors is displayed using the three cells is shown.

  In the comparative example, when displaying any one color of R, G, and B, one of the three cells # 1 to # 3 displays R, G, or B that is the target display color, and the other These two are achromatic (W or K) display. Therefore, the area ratio of the pixels that actually display the target display color is 1/3. In the comparative example, when red is displayed, for example, two cells # 2 to # 3 are displayed in black, and red is displayed in one cell # 1.

On the other hand, in the case of this embodiment, one cell 6 displays with a certain color particle, and two cells 6 use two color particles that are different from the color particle complementary to the color particle. Each display is done. Therefore, the area ratio of the pixel displaying the target display color (red, green, blue, cyan, magenta, yellow) can be set to 100%, and the efficiency and saturation of single color display can be improved. .
In addition, when performing white display, all the three cells # 1 to # 3 may be white display by the white large particles 5C. Since all of the cells 6 for 3 pixels can display white by the white large particles 5C, it is possible to minimize the decrease in the reflectance of the white display, and it is possible to suppress whiteness with higher brightness (ideally white Is pure white).

  In addition, when performing black display, each of the three cells # 1 to # 3 includes color particles of any one color of R, G, and B and color particles of any one color of cyan, magenta, and yellow. May be displayed at the same time. In other words, when the first cell # 1 is controlled to be displayed by the color particle 5B together with the color particle 5A, each of the second and third cells # 2 and # 3 is colored together with the color particle 5B. The display state is controlled by the particles 5A.

In this case, all three cells 6 are mixed color display by the color particles 5A and 5B, and black is expressed by a total of six mixed colors of R, G, B, cyan, magenta and yellow. Therefore, it is possible to improve the black display absorptivity compared to the case of displaying black with three colors of R, G and B, or a mixed color of three colors of cyan, magenta and yellow. Can be expressed.
The display color control of the three cells # 1 to # 3 as described above individually controls the polarities of the voltages applied to the four electrodes 71, 72, 81 and 82 provided in one cell 6, in other words. For example, this can be realized by controlling the voltage polarity pattern.

  In the voltage polarity pattern shown in FIG. 8, the color particles 5A and 5B are charged with positive and negative polarities so that the uneven distribution regions and the electrophoresis paths in the cells 6 of the color particles 5A and 5B can be individually controlled. For example, it is assumed that the color particle 5A that is one of R, G, and B is positively charged, and the complementary color particle 5B that is any one of cyan, magenta, and yellow is negatively charged. Further, as schematically shown in FIG. 9A, the electrodes 71, 72, 81 and 82 are represented by X1, X2, X3 and X4 in FIG. 8, respectively. Here, the pair of electrodes X1 and X3 can take two states of positive polarity (+) or ground (g), and the pair of electrodes X2 and X4 can be two of negative polarity (−) or ground (g). The state can be taken.

The control circuit 91 shown in FIG. 2 described above controls the polarities of the individual electrodes X1, X2, X3, and X4 based on the voltage polarity pattern illustrated in FIG. Efficiency and saturation can be improved. The voltage polarity pattern information described above can be stored in a memory (not shown) in the control circuit 91 as table format data or the like.
Hereinafter, electrode polarity control when displaying red (R), white (W), and black (K) in the three cells # 1, # 2, and # 3 will be described as an example.

(Displayed in red)
When red (R) is displayed in the three cells # 1, # 2, and # 3, as illustrated in the schematic partial cross-sectional view of FIG. 10, the control circuit 91 controls the one surface electrode X1 for the cell # 1. Is controlled to the ground state, and the polarity of the other surface electrode X2 is controlled to the opposite polarity (-) to the charging polarity (+) of the R particles. Further, the control circuit 91 sets the polarity of one back electrode X3 (or X4) to the same polarity (+) as the charging polarity (+) of the R particles, and sets the polarity of the other back electrode X4 (or X3) to the ground state. Control each one.

For the cell # 2, the control circuit 91 sets the polarity of one surface electrode X1 to a polarity (+) opposite to the charged polarity (−) of the Ma particles, and sets the polarity of the pole X2 to the ground state on the other surface. Control. Further, the control circuit 91 sets the polarity of one back electrode X3 (or X4) to the ground state, and sets the polarity of the other back electrode X4 (or X3) to the opposite polarity (-) to the charging polarity (+) of the G particles. To control.
For the cell # 3, the control circuit 91 controls the polarity of one surface electrode X1 to a polarity (+) opposite to the charging polarity (-) of the Ye particles and the polarity of the other surface electrode X2 to the ground state. To do. Further, the control circuit 91 sets the polarity of one back electrode X3 (or X4) to the ground state, and sets the polarity of the other back electrode X4 (or X3) to a polarity (-) opposite to the charging polarity (+) of the B particles. Control.

  With the polarity control described above, positively charged R particles in cell # 1, negatively charged Ma particles in cell # 2, and negatively charged Ye particles in cell # 3 are attracted to the surface electrodes X1 and X2, which are the viewing side, respectively. On the other hand, in each of the cells # 1, # 2 and # 3, the particles having the opposite polarity to the R, Ma and Ye particles and having a complementary color relationship are attracted to the back electrode X4 side.

Therefore, cell # 1 displays red color due to R particles, and cells # 2 and # 3 indicate juxtaposed mixed color display based on Ma particles and Ye particles of two colors different from Cy particles complementary to the R particles (red color). Equivalent to display). In addition, the Ma light incident on the cell # 2 and reflected on the spherical surface of the W particle and incident on the cell # 3 via the partition wall 30 is reflected on the spherical surface of the W particle of the cell # 3, and is reflected on the cell # 3. By transmitting Ye particles unevenly distributed on the display surface side, Ma and Ye are mixed and mixed color (equivalent to red light) and emitted to the viewer side. Further, the Ye light incident on the cell # 3, reflected by the spherical surface of the W particle and incident on the cell # 2 via the partition wall 30, is reflected by the spherical surface of the W particle of the cell # 2, and is displayed on the cell # 2. By passing through the Ma particles unevenly distributed on the surface side, Ye and Ma are mixed and mixed color light (equivalent to red light) and emitted to the viewing side.
Therefore, the three cells # 1, # 2, and # 3 are formed by the red light of the cell # 1, the stacked mixed light of the cell # 2, the stacked mixed light of the cell # 3, and the juxtaposed mixed light of the cell # 2 and the cell # 3. Each is displayed in red.

(White display)
When displaying white (W) in the three cells # 1, # 2, and # 3, the control circuit 91 includes cells # 1, # 2, and # 3, respectively, as illustrated in the schematic partial sectional view of FIG. The polarity of the surface electrodes X1 and X2 is controlled to the ground state (nonpolar). Further, the control circuit 91 controls the polarities of the back electrodes X3 and X4 of the cells # 1, # 2 and # 3 to be opposite to each other. Note that which of the back electrodes X3 and X4 is controlled to be positive or negative may be the same or different for each of the cells # 1 to # 3.
As a result, in each cell # 1, # 2 and # 3, the positively or negatively charged color particles 5A and 5B are attracted to the back electrode X3 and X4 side, respectively, and are hidden under the white large particles 5C. Accordingly, the three cells # 1, # 2, and # 3 are each displayed in white.

(Black display)
When displaying black (K) in the three cells # 1, # 2, and # 3, the control circuit 91 includes cells # 1, # 2, and # 3, respectively, as illustrated in the schematic partial sectional view of FIG. The polarities of the surface electrodes X1 and X2 are controlled to be opposite to each other. Further, the control circuit 91 controls the polarities of the back electrodes X3 and X4 of the cells # 1, # 2 and # 3 to the ground state. Note that which of the surface electrodes X1 and X2 is controlled to be positive or negative may be the same or different for each of the cells # 1 to # 3.

  As a result, Cy particles and R particles in cell # 1, Ma particles and G particles in cell # 2, and Ye particles and B particles in cell # 3 are attracted to the surface electrodes X1 and X2, respectively. As a result, the white large particles 5C are obscured by the color particles 5A and 5B in the cells # 1, # 2 and # 3, respectively. Therefore, the three cells # 1, # 2, and # 3 are displayed in black, and the case where black is displayed in three colors of R, G, and B, or a mixed color of three colors of cyan, magenta, and yellow is displayed. The absorptance of black display can be improved, and black with a lower brightness can be expressed.

  Note that the voltage polarity pattern illustrated in FIG. 8 is merely an example, and may be appropriately changed as long as the combination of display colors illustrated in FIG. 7 is possible. Illustratively, the control circuit 91 is configured such that at a certain timing T1 (T1 is a positive real number), one of the electrodes X1 and X2 (or the electrodes X3 and X4) is positive or negative and the other is ground. From the state, at the subsequent timing T2 (> T1), the electrode in the ground state may be controlled to be positive or negative. In other words, after only one of the electrodes X1 and X2 (or the electrodes X3 and X4) is controlled to be positive or negative, both may be controlled to have the same positive or negative polarity. Accordingly, it is possible to control the color particles 5A or 5B to be dispersed in the vicinity of the electrodes X1 and X2 (or the electrodes X3 and X4) after being once unevenly distributed in the vicinity of the negative or positive electrode.

Further, the control circuit 91 controls the polarity and / or magnitude of the voltage applied to each of the electrodes X1 to X4, so that the color particle 5A or 5B in the cell 6 and the substrate 4 on the viewing side (see FIG. 2). It is also possible to control the distance between the two. By this control, the electrophoretic display device 1 (electrophoretic display body 2) can also display an intermediate color.
When black is displayed in the three cells # 1 to # 3 as illustrated in FIG. 12, the control circuit 91 controls the polarities of the surface electrodes X1 and X2 to be opposite to each other, The polarity of X2 may be exchanged at least once within a predetermined time. By performing the polarity switching, an alternating electric field is generated in the vicinity of the viewing side of the cells # 1 to # 3, and the colored particles 5A and 5B drawn near the surface electrodes X1 and X2 on the viewing side can be mixed. . As a result, the uneven distribution of the color particles 5A and 5B can be eliminated or reduced, and the reflectance of black display can be reduced to reduce the saturation of black display. Therefore, it becomes possible to express blackish black.

(3-electrode structure)
Next, the case where the electrode structure is a three-electrode structure will be described.
Here, FIG. 13 is a diagram illustrating an example of a voltage polarity pattern in the case of the three-electrode structure. 14 and 15 are schematic partial cross-sectional views of the electrophoretic display device showing an example of the voltage polarity of each electrode when performing red display and white display.
Here, as illustrated in the schematic partial cross-sectional view of FIG. 14, a total of three electrodes, one front surface electrode 73 and two back surface electrodes 81 and 82, are provided for each cell 6. By individually controlling the polarities of the electrodes 73, 81 and 82 by the control circuit 91, it is possible to display each color (eight colors) including white display. The surface electrode 73 can be rectangular as shown in FIG.

In the voltage polarity pattern shown in FIG. 13, the color particles 5A and 5B are charged with positive and negative polarities so that the uneven distribution regions and the electrophoresis paths in the cells 6 of the color particles 5A and 5B can be individually controlled. For example, it is assumed that the color particle 5A that is one of R, G, and B is positively charged, and the complementary color particle 5B that is any one of cyan, magenta, and yellow is negatively charged. When the charging polarity of the color particle 5A and the complementary color particle 5B is reversed between positive and negative, the polarity of the electrode polarity illustrated in Table 5 may be reversed. Further, as schematically shown in FIG. 9B, in the three-electrode structure, the electrodes 73, 81 and 82 are represented by X1, X3 and X4 in FIG. 13, respectively.
Hereinafter, electrode polarity control when displaying red (R) and white (W) in the three cells # 1, # 2, and # 3 will be described as an example.

(Displayed in red)
When displaying red (R) in the three cells # 1, # 2, and # 3, the control circuit 91 controls the polarity of the surface electrode X1 for the cell # 1, as illustrated in the schematic partial cross-sectional view of FIG. Is controlled to a polarity (-) opposite to the charged polarity (+) of the R particles, the polarity of one back electrode X3 (or X4) is grounded, and the polarity of the other back electrode X4 (or X3) is Cy particles The charging polarity (−) is controlled to the opposite polarity (+).

For cell # 2, the control circuit 91 controls the polarity of the surface electrode X1 to the polarity (+) opposite to the charged polarity (−) of the Ma particles, and the polarity of one back electrode X3 (or X4). In the ground state, the polarity of the other back surface electrode X4 (or X3) is controlled to a polarity (-) opposite to the charging polarity (+) of the G particles.
For cell # 3, the control circuit 91 controls the polarity of the surface electrode X1 to the polarity (+) opposite to the charging polarity (−) of the Ye particles, and the polarity of one back electrode X3 (or X4). In the ground state, the polarity of the other back electrode X4 (or X3) is controlled to a polarity (-) opposite to the charging polarity (+) of the B particles.

With the above polarity control, positively charged R particles in cell # 1, negatively charged Ma particles in cell # 2, and negatively charged Ye particles in cell # 3 are attracted to the surface electrode X1 side, which is the viewing side, respectively. In each of the cells # 1, # 2 and # 3, the particles which are charged with the opposite polarity to the R, Ma and Ye particles and have a complementary color relationship are attracted to the back electrode X4 side. Therefore, cell # 1 displays red due to R particles, and cells # 2 and # 3 display juxtaposed mixed color display (two red colors) of Ma particles and Ye particles that are different from Cy particles complementary to the R particles. Equivalent to display). In addition, the Ma light incident on the cell # 2 and reflected on the spherical surface of the W particle and incident on the cell # 3 via the partition wall 30 is reflected on the spherical surface of the W particle of the cell # 3, and is reflected on the cell # 3. By transmitting Ye particles unevenly distributed on the display surface side, Ma and Ye are mixed and mixed color (equivalent to red light) and emitted to the viewer side. Further, the Ye light incident on the cell # 3, reflected by the spherical surface of the W particle and incident on the cell # 2 via the partition wall 30, is reflected by the spherical surface of the W particle of the cell # 2, and is displayed on the cell # 2. By passing through the Ma particles unevenly distributed on the surface side, Ye and Ma are mixed and mixed color light (equivalent to red light) and emitted to the viewing side.
Accordingly, the three cells # 1, # 2, and # 3 are formed by the red light of the cell # 1, the stacked mixed light of the cell # 2, the stacked mixed light of the cell # 3, and the juxtaposed mixed light of the cell # 2 and the cell # 3. Are displayed in red.

(White display)
When displaying white (W) in three cells # 1, # 2, and # 3, the control circuit 91 includes cells # 1, # 2, and # 3, respectively, as illustrated in the schematic partial sectional view of FIG. The polarity of the front surface electrode X1 is controlled to the ground state (nonpolarity), while the polarity of the back surface electrodes X3 and X4 of the cells # 1, # 2 and # 3 is controlled to be opposite to each other. Note that which of the back electrodes X3 and X4 is controlled to be positive or negative may be the same or different for each of the cells # 1 to # 3.
As a result, in each cell # 1, # 2 and # 3, the positively or negatively charged color particles 5A and 5B are attracted to the back electrode X3 and X4 side, respectively, and are hidden under the white large particles 5C. Accordingly, the three cells # 1, # 2, and # 3 are each displayed in white.

(Method of fixing white particles)
FIGS. 16A to 16D are diagrams illustrating an example of a method for fixing the white large particles 5C to the bottom surface of the cell 6.
When fixing the white large particles 5C to the bottom surface in each cell 6, first, as shown in FIG. 16 (a), a plurality of rod-shaped application portions 41 attached in accordance with the arrangement interval of each cell 6 are provided. A jig 40 is prepared, and the adhesive 50 is attached to the tip of the application part 41.

Next, as shown in FIGS. 16 (b) and 16 (c), the jig 40 is operated to lower the coating unit 41 into the cell 6 before the dispersion system 5 is supplied. The adhesive 50 attached to the tip of the application part 41 is applied to the center of the bottom part.
After applying the adhesive, before the adhesive is solidified, as shown in FIG. 16D, the white large particles 5C are arranged on the adhesive 50 applied to the bottom surface of each cell 6, The adhesive 50 is solidified by natural drying, heat drying, or the like, and the white large particles 5C are fixed.

  In the example of FIG. 16, a method of fixing a single white large particle 5 </ b> C is shown. However, when fixing a plurality of white large particles 5 </ b> C to each cell 6, the jig 40 is used to fix the tip of the application unit 41. The operation of applying the adhesive 50 and applying the adhesive 50 to the center of the bottom surface is repeated while shifting the application position. Or it can respond by the method of providing the application part 41 with respect to each cell 6, and apply | coating at once.

(Example)
Next, an example using the electrophoretic display device 1 of the present embodiment will be described.
In this example, the electrophoretic display device of the present embodiment has the configuration exemplified in FIGS. 2, 4, 6A and 6B, and the electrophoretic display device of the comparative example is shown in FIG. The configuration exemplified in 6 (c) was used.
Here, FIG. 18A is an xy chromaticity diagram created using measured values measured by the electrophoretic display devices of the present embodiment and the comparative example, and FIG. 18B is an xy chromaticity diagram of the present invention and the comparative example. It is a figure which shows the measured value used for preparation of a chromaticity diagram. In FIG. 18A, a broken line A is a broken line corresponding to the present embodiment, and a broken line B is a broken line corresponding to the comparative example.

In the xy chromaticity diagram in which all colors are expressed, the vividness increases toward the periphery and becomes monochromatic light at the boundary. Therefore, the larger the area surrounded by the broken line formed by connecting the three primary colors of Re, Gr, and Bu and the plot of (x, y) values for the three primary colors of C, M, and Y with a straight line, the more the value is on the peripheral side (saturation) Is large).
Specifically, the color gamut area of the polygonal line A of this embodiment is 0.05, and the color gamut area of the polygonal line B of the comparative example is 0.038. That is, in the configuration of the present embodiment, the color gamut area is 1.33 times that of the comparative example using small particles as white particles.
Therefore, since the color gamut area of the polygonal line A is larger than that of the comparative example, it can be said that the display result of the electrophoretic device of the present invention has improved saturation compared to the comparative example.

(Modification 1)
Next, Modification Example 1 of the electrophoretic display device 1 of the present embodiment will be described.
FIG. 19 is a schematic partial cross-sectional view showing the structure of the electrophoretic display device of the first modification.
In the electrophoretic display device 1 having the above-described three-electrode structure, as shown in FIG. 19, the backside electrodes 81 and 82 are provided on the backside of the substrate 3 facing the peripheral edge of the bottom surface of the cell 6, It is configured to be provided at a position that does not overlap the back surface electrodes 81 and 82 on the substrate 4 when viewed from the viewing direction 100. In addition, a black matrix may be provided as a shielding film having a light shielding property at a position where the back electrodes 81 and 82 can be viewed in plan view from the viewing direction 100 on the substrate 4.

With such a configuration, since the color particles unevenly distributed on the back electrodes 81 and 82 can be concealed from the viewing side by the black matrix, the color particles unevenly distributed on the back electrodes 81 and 82 are formed by the white large particles 5C. It is not necessary to conceal, and the arrangement of the white large particles 5C becomes easy.
As a black matrix material, carbon black, low-order titanium oxide, iron oxide, chromium, silver fine particles, or the like can be used. In addition, gold, platinum group elements, or their alloys, or any of the above metals or alloys with silver added, are added to a metal such as copper, nickel, iron, etc. A black alloy having a black oxide layer with good properties can be used.

(Modification 2)
The electrophoretic display device 1 described above can be provided in various electronic devices. As an example of an electronic apparatus provided with the electrophoretic display device 1, an electronic paper, an electronic book, a television, a viewfinder type, a monitor direct-view type video tape recorder, a car navigation device, a pager, an electronic notebook, a calculator, an electronic newspaper, a word processor, Examples include personal computers, workstations, videophones, POS terminals, and devices equipped with touch panels.

In the above embodiment, the front surface electrodes 71, 72, 73 correspond to the first electrode, the back surface electrodes 81, 82 correspond to the second electrode, the white large particles 5C correspond to the reflecting member, and the control circuit 91. Corresponds to voltage application means.
In the above embodiment, the example in which the white large particles 5C are fixed to the inside of the cell 6 has been described. However, the configuration is not limited to this, and the white large particles 5C may be fixed.

Moreover, although the said embodiment gave and demonstrated the example which comprises 1 pixel by 3 pixels (each 3 cell 6), it may comprise not only this structure but 1 pixel by 2 pixels. In the case of forming one pixel with two pixels, for example, a configuration in which white large particles 5C and black particles are sealed in both of the two pixels, magenta particles are sealed in one, and yellow particles are sealed in the other is considered.
With this configuration, it is possible to perform white display, black display, and mixed color display of magenta color and yellow color (parallel color mixture + stacked color mixture).

DESCRIPTION OF SYMBOLS 1 ... Electrophoretic display device, 2 ... Electrophoretic display body, 3, 4 ... Substrate, 5 ... Dispersion liquid, 5A-5B ... (Electrophoresis) particle, 5C ... White large particle, 6 ... Cell, 9 ... Circuit board, DESCRIPTION OF SYMBOLS 30 ... Partition, 31 ... Recessed part, 40 ... Jig, 41 ... Application part, 50 ... Adhesive, 70 ... Electrode part, 71 (X1), 72 (X2), 73 (X1) ... Electrode (surface electrode), 80 ... Electrode unit 81 (X3), 82 (X4), 83 (X3) (back electrode), 91 control circuit, L1 incident light, L2 reflected light (scattered light), L3 laminated light mixture

Claims (6)

A substrate,
A plurality of cells formed by spatially partitioning one surface of the substrate with a plurality of light-transmitting partitions;
A first electrode having a transparent electrode surface provided on the opening side of each of the cells and serving as a display surface in plan view from the viewing side;
A second electrode provided on the bottom side of each cell and having an electrode surface facing the bottom surface of each cell;
A dispersion medium having transparency and insulation provided inside each of the cells;
At least one kind of colored electrophoretic particles charged in a predetermined polarity, dispersed in the dispersion medium of each cell and colored in a different color from the adjacent cells;
Reflecting the light transmitted through the first electrode from the viewing side provided on the inner side of each cell, the reflected light is incident on an adjacent cell through the partition wall, and from the adjacent cell A reflecting member having a reflecting portion for reflecting the light incident through the partition wall and causing the reflected light to enter the first electrode of the cell;
Voltage application means for applying a voltage of a predetermined polarity to the first electrode and the second electrode ,
The reflecting member is a single white particle having a size capable of concealing the second electrode within a range that does not hinder migration of the colored electrophoretic particles in a plan view from the viewing side,
An electrophoretic display device , wherein at least a portion of the bottom portion of the cell that does not overlap with the reflecting member is colored white when viewed from the viewing side . Each adjacent cell in the plurality of cells constitutes one pixel,
Each of the three cells as the first to third cells,
Inside the first cell, as the colored electrophoretic particles, the first electrophoretic particles colored in red and charged in opposite polarities are colored in a cyan color that is complementary to the red color. Second electrophoretic particles
Inside the second cell, the colored electrophoretic particles are colored in a magenta color having a complementary color relationship with the third electrophoretic particles colored in green and charged in opposite polarities. A fourth electrophoretic particle,
Inside the third cell, as the colored electrophoretic particles, the fifth electrophoretic particles colored in blue and charged in opposite polarities are colored yellow that is complementary to the blue color. The electrophoretic display device according to claim 1, further comprising sixth electrophoretic particles.   3. The reflecting member according to claim 1, wherein the reflecting member is an uncharged white particle having a size larger than that of the colored electrophoretic particle or having a smaller charge amount than the colored electrophoretic particle. Electrophoretic display device.   The electrophoretic display device according to claim 3, wherein the white particles as the reflecting member are fixedly provided inside the cell. An electronic apparatus comprising the electrophoretic display device according to any one of claims 1 to 4 . A substrate,
A plurality of cells formed by spatially partitioning one surface of the substrate with a plurality of light-transmitting partitions;
A first electrode having a transparent electrode surface provided on the opening side of each of the cells and serving as a display surface in plan view from the viewing side;
A second electrode provided on the bottom side of each cell and having an electrode surface facing the bottom surface of each cell;
A dispersion medium having transparency and insulation provided inside each of the cells;
At least one kind of colored electrophoretic particles charged in a predetermined polarity, dispersed in the dispersion medium of each cell and colored in a different color from the adjacent cells;
Reflecting the light transmitted through the first electrode from the viewing side provided on the inner side of each cell, the reflected light is incident on an adjacent cell through the partition wall, and from the adjacent cell A reflection member having a reflection part that reflects light incident through the partition wall and causes the reflected light to enter the first electrode of the cell ;
The reflecting member is a single white particle having a size capable of concealing the second electrode within a range that does not hinder migration of the colored electrophoretic particles in a plan view from the viewing side,
An electrophoretic display , wherein at least a portion of the bottom of the cell that does not overlap with the reflecting member is colored white when viewed from the viewing side .

Images