JP2012083386A - Display sheet driving method, control device and display device and electronic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display sheet driving method, a control device, and a display device and electronic equipment which can attain efficient driving.SOLUTION: A display device 20 is capable of taking a white display state for displaying the color of a while particle 5A, a red display state for displaying the color of a red particle 6A and a black display state for displaying black to be a mixed color of the red particle and a cyan colored dispersant. Voltage to be applied to an electrode to switch between the white display state and the black display state and voltage to be applied to the electrode to switch between the red display state and the black display state satisfy at least one of smaller sizes and shorter application time than voltage to be applied to the electrode to switch between the white display state and the red display state.

Description

  The present invention relates to a display sheet driving method, a control device, a display device, and an electronic apparatus.

For example, an electrophoretic display using particle electrophoresis is known as an image display unit of electronic paper (see, for example, Patent Document 1). The electrophoretic display has excellent portability and power saving, and is particularly suitable as an image display unit for electronic paper.
Patent Document 1 discloses an electrophoretic display device that has a pair of electrodes (a common electrode and a plurality of pixel electrodes) arranged opposite to each other and a plurality of divided cells provided therebetween, and is capable of full color display. Are listed. In this electrophoretic display device, one pixel is composed of three cells adjacent to each other. Specifically, the first cell is filled with a dispersion liquid in which white and yellow electrophoretic particles are dispersed in a blue dispersion medium, and the second cell is electrophoresed with white and magenta. A dispersion liquid in which particles are dispersed in a green dispersion medium is filled, and a third cell is filled with a dispersion liquid in which white and cyan electrophoretic particles are dispersed in a red dispersion medium. . The three cells in one pixel are configured to represent a desired color in the one pixel by independently controlling the state of the electrophoretic particles (eg, uneven distribution position).
In the first cell of such an electrophoretic display device (the same applies to the second cell and the third cell except that the colors are different), the color of white particles is displayed by applying a desired voltage to the electrodes. A white display state, a yellow display state in which white of yellow particles is displayed, and a blue display state in which the color of the dispersion is displayed.

  However, for example, the voltage pattern for changing to the white display state is the same regardless of what the display state immediately before the first cell is, that is, applied to change from the yellow display state to the white display state. Since the voltage to be applied is the same as the voltage applied to change the blue display state to the white display state, there is a possibility that an excessive voltage may be applied. There is a problem that the display quality is deteriorated because it is stuck to the inner wall of the cell and cannot move.

JP 2010-72617 A

  An object of the present invention is to provide, for example, a display sheet driving method, a control device, a display device, and an electronic apparatus, which can improve driving efficiency.

Such an object is achieved by the present invention described below.
The display sheet driving method of the present invention includes a first particle that is white and is positively or negatively charged, and a second particle that is different in color from the first particle and is charged at a polarity opposite to the first particle. And a display sheet driving method comprising a display layer filled with a dispersion liquid in which a dispersion medium of a color complementary to the color of the second particles is dispersed,
The display sheet causes the first particles to be unevenly distributed on the display surface side provided on one side of the display layer by applying an electric field to the display layer, and the color of the first particles on the display surface. A second color display state in which the second particles are unevenly distributed on the display surface side of the display layer and the color of the second particles is displayed on the display surface; Taking one of the third color display states in which the second particles are dispersed in a dispersion medium to display a mixed color of the second particles and the dispersion medium on the display surface; Can
In order to switch between the first color display state and the third color display state rather than an electric field applied to the display layer to switch between the first color display state and the second color display state. At least one of an electric field applied to the display layer and an electric field applied to the display layer to switch between the second color display state and the third color display state; It is characterized by satisfying.
As a result, it is possible to provide a display sheet driving method capable of increasing the driving efficiency.

According to the display sheet driving method of the present invention, the second color display state and the second color display state are more effective than the electric field applied to the display layer in order to switch between the first color display state and the third color display state. In order to switch between the three color display states, at least one of a magnitude of an electric field applied to the display layer and a short action time is satisfied.
Thereby, it is possible to further improve the efficiency of driving the display sheet.

In the display sheet driving method of the present invention, the mobility of the first particles in the dispersion medium is preferably different from the mobility of the second particles in the dispersion medium.
Thereby, black with a lower reflectance can be displayed.
In the display sheet driving method of the present invention, it is preferable that the mobility of the first particles in the dispersion medium is equal to the mobility of the second particles in the dispersion medium.
Thereby, control of 1st particle | grains and 2nd particle | grains can be performed easily.

In the display sheet driving method of the present invention, when switching from the first color display state to the third color display state, it is preferable to pass through the second color display state.
Thereby, the black reflectance to be displayed can be aligned more reliably.
In the display sheet driving method of the present invention, when switching from the second color display state to the third color display state, it is preferable to pass through the first color display state.
Thereby, the black reflectance to be displayed can be aligned more reliably.

The control device of the present invention includes a first particle that is white and is positively or negatively charged, and a second particle that is different in color from the first particle and is charged on the opposite pole of the first particle. A display layer filled with a dispersion liquid dispersed in a dispersion medium having a color complementary to the color of the second particles, and an electric field is applied to the display layer, whereby the first particles In a first color display state in which the color of the first particles is displayed on the display surface by unevenly distributing to the display surface side provided on one side of the display layer, and the second particles in the display layer A second color display state in which the second particles are unevenly distributed on the display surface side and display the color of the second particles on the display surface; and the second particles are dispersed in the dispersion medium and the second particles are dispersed on the display surface. Any one of the third color display states for displaying the mixed color of the particles and the dispersion medium can be taken. A control device for controlling the drive of the display sheet,
In order to switch between the first color display state and the third color display state rather than an electric field applied to the display layer to switch between the first color display state and the second color display state. At least one of an electric field applied to the display layer and an electric field applied to the display layer to switch between the second color display state and the third color display state; The driving of the display sheet is controlled so as to satisfy the condition.
Thereby, it is possible to provide a display sheet control device capable of increasing the driving efficiency.

The display device of the present invention includes first particles that are white and are positively or negatively charged, and second particles that are different in color from the first particles and are charged on the opposite pole of the first particles. A display layer filled with a dispersion liquid dispersed in a dispersion medium having a color complementary to the color of the second particles;
By applying an electric field to the display layer, the first particles are unevenly distributed on the display surface side provided on one side of the display layer, and the color of the first particles is displayed on the display surface. The color display state, the second particles are unevenly distributed on the display surface side of the display layer, and the second color display state displays the color of the second particles on the display surface. It can take any one of the third color display states in which the second particles are dispersed to display the mixed color of the second particles and the dispersion medium on the display surface,
In order to switch between the first color display state and the third color display state rather than an electric field applied to the display layer to switch between the first color display state and the second color display state. At least one of an electric field applied to the display layer and an electric field applied to the display layer to switch between the second color display state and the third color display state; It is characterized by satisfying.
Thereby, it is possible to provide a display device capable of increasing driving efficiency.
An electronic apparatus according to the present invention includes the display device according to the present invention.
As a result, a highly reliable electronic device can be obtained.

It is sectional drawing which shows 1st Embodiment of the display apparatus of this invention. It is a top view of the display apparatus shown in FIG. FIG. 2 is an enlarged cross-sectional view illustrating one pixel of the display device illustrated in FIG. 1. It is sectional drawing which shows the display state of the display apparatus shown in FIG. It is a figure which shows the voltage applied to the 1st electrode of the display apparatus shown in FIG. It is a graph which shows the relationship between the magnitude | size of an applied voltage, and the movement distance of particle | grains. It is a figure which shows the voltage applied to the 1st electrode of the display apparatus shown in FIG. It is sectional drawing which shows the black display state of a display apparatus. It is sectional drawing which shows the black display state of a display apparatus. It is sectional drawing which shows 5th Embodiment of the display apparatus of this invention. It is a perspective view which shows embodiment at the time of applying the electronic device of this invention to electronic paper. It is a figure which shows embodiment at the time of applying the electronic device of this invention to a display.

Hereinafter, a display sheet driving method, a control device, a display device, and an electronic apparatus according to the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.
1. Display Device First, a display device incorporating the display sheet of the present invention will be described.

<First Embodiment>
1 is a cross-sectional view showing a first embodiment of the display device of the present invention, FIG. 2 is a plan view of the display device shown in FIG. 1, and FIG. 3 shows one pixel of the display device shown in FIG. FIG. 4 is a sectional view showing a display state of the display device shown in FIG. 1, FIG. 5 is a diagram showing a voltage applied to the first electrode of the display device shown in FIG. 1, and FIG. It is a graph which shows the relationship between the magnitude | size of a voltage, and the movement distance of particle | grains. In the following description, for convenience of explanation, the upper side in FIGS. 1, 2, 3, and 4 will be described as “upper” and the lower side as “lower”.

A display device 20 (display device of the present invention) shown in FIG. 1 is an electrophoretic display device that displays a desired image using particle migration. The display device 20 includes a display sheet 21 and a circuit board (control device) 22.
As shown in FIG. 1, a display sheet 21 is provided on a substrate 12 having a flat base 2 and a second electrode 4 provided on the lower surface of the base 2, and filled with a dispersion 100. Display layer 400 having a plurality of cells (filling portions) 410 formed thereon.

  On the other hand, the circuit board 22 is provided with a counter substrate 11 having a flat base 1 and a plurality of first electrodes 3 provided on the upper surface of the base 1, and a counter substrate 11 (base 1) not shown. Circuit. The circuit includes, for example, TFTs arranged in a matrix, a plurality of gate lines and a plurality of data lines formed corresponding thereto, a gate driver that applies a desired voltage to the gate lines, and a data line. It has a data driver that applies a desired voltage, and a control unit (controller) that controls the driving of the gate driver and the data driver.

Hereinafter, the structure of each part is demonstrated sequentially.
The base 1 and the base 2 are each composed of a sheet-like (flat plate) member, and have a function of supporting and protecting each member disposed therebetween. Each of the base portions 1 and 2 may be either flexible or hard, but is preferably flexible. By using the bases 1 and 2 having flexibility, it is possible to obtain a display device 20 having flexibility, that is, for example, a display device 20 useful in constructing electronic paper.

  When each base part (base material layer) 1 and 2 is flexible, the constituent materials thereof are, for example, polyesters such as PET (polyethylene terephthalate) and PEN (polyethylene naphthalate), polyethylene, etc. Polyolefins, modified polyolefins, polyamides, thermoplastic polyimides, polyethers, polyether ether ketones, various thermoplastic elastomers such as polyurethanes and chlorinated polyethylenes, or their main copolymers, blends, polymer alloys, etc. 1 type or 2 types or more of these can be mixed and used.

  The average thicknesses of the bases 1 and 2 are appropriately set depending on the constituent materials, applications, and the like, and are not particularly limited. However, when having flexibility, the average thickness is about 20 μm or more and 500 μm or less. Preferably, it is about 25 μm or more and 250 μm or less. Thereby, size reduction (especially thickness reduction) of the display apparatus 20 can be achieved, aiming at harmony with the softness | flexibility of the display apparatus 20, and intensity | strength.

  The first electrode 3 and the second electrode 4 that form a layer (film shape) are provided on the surfaces of the bases 1 and 2 on the display layer 400 side, that is, on the upper surface of the base 1 and the lower surface of the base 2, respectively. ing. In the present embodiment, the second electrode 4 is a common electrode, and the first electrode 3 is an individual electrode (pixel electrode connected to the switching element) divided in a matrix (matrix). Further, the first electrode 3 is provided corresponding to each cell 410 included in the display layer 400 (so that one first electrode 3 is positioned in one cell 410). Note that the second electrode 4 may also be divided into a plurality of parts in the same manner as the first electrode 3.

The constituent materials of the electrodes 3 and 4 are not particularly limited as long as they are substantially conductive, for example, metal materials such as gold, silver, copper, aluminum or alloys containing these, carbon black, etc. An ionic substance such as NaCl, Cu (CF ₃ SO ₃ ) _{2 in} a matrix resin such as a carbon-based material such as polyacetylene, polyfluorene or a derivative thereof, or a matrix resin such as polyvinyl alcohol or polycarbonate. Various conductive materials such as dispersed ion conductive polymer materials, conductive oxide materials such as indium oxide (IO), indium tin oxide (ITO), fluorine-doped tin oxide (FTO), etc. One or more of these can be used in combination.
The average thickness of the electrodes 3 and 4 is appropriately set depending on the constituent material and application, and is not particularly limited, but is preferably about 0.01 μm or more and 10 μm or less, preferably 0.02 μm or more and 5 μm. More preferably, it is about the following.

  Here, among the bases 1 and 2 and the electrodes 3 and 4, the base and the electrode disposed on the display surface side are each transparent, that is, substantially transparent (colorless and transparent, colored and transparent). Or translucent). In the present embodiment, since the surface (upper surface) of the substrate 12 constitutes the display surface 121, at least the base 2 and the second electrode 4 are substantially transparent. Thereby, the state of the particles 5 and 6 in the dispersion liquid 100, that is, the information (image) displayed on the display device 20 can be easily recognized visually from the display surface 121 side.

  In the display sheet 21, a display layer 400 is provided in contact with the lower surface of the second electrode 4. The display layer 400 is configured by arranging a plurality of cells (filling portions) 410 filled (encapsulated) with the dispersion liquid (electrophoretic dispersion liquid) 100 in a matrix. The dispersion liquid 100 is a dispersion in which first particles 5 and second particles 6 charged to opposite poles are dispersed in a dispersion medium (liquid phase dispersion medium) 7.

As shown in FIG. 1, the display layer 400 includes a base body 401 in which a plurality of concave portions 401a are formed in a matrix (matrix shape), and a lid body that is bonded to the base body 401 so as to cover (close) the openings of the concave portions 401a. 402, whereby a plurality of cells 410 are formed.
The substrate 401 has a relatively high insulating property and the impermeability of the dispersion liquid 100. The constituent material of the base 401 is not particularly limited. For example, various resin materials such as an epoxy resin, an acrylic resin, a urethane resin, a melamine resin, and a phenol resin, silica, alumina, titania, and the like. These ceramic materials can be used, and one or more of them can be used in combination.

One lid 402 also has a relatively high insulating property and the impermeability of the dispersion liquid 100. Further, the lid body 402 is substantially colorless and transparent so that the inside of the cell 410 can be visually recognized from the outside of the cell 410. The constituent material of the lid 402 is not particularly limited. For example, polyolefin such as polyethylene, polypropylene, ethylene-vinyl acetate copolymer, modified polyolefin, polyamide (eg, nylon 6, nylon 66), styrene Various thermoplastic elastomers such as polyvinyl chloride, polyurethane, polyester, fluororubber, chlorinated polyethylene, etc., or copolymers, blends, polymer alloys, etc. mainly composed of these. One or two or more of them can be used in combination.
Note that the lid 402 may be omitted, and in that case, the substrate 12 may cover the opening of the recess 401a. Thereby, the configuration of the apparatus becomes simple. Further, since the number of members interposed between the display surface 121 and the dispersion liquid 100 can be reduced, light absorption can be suppressed, and a clearer and brighter image can be displayed.

As shown in FIG. 2, in the display device 20, one pixel Pix is configured by three adjacent cells 410, and a plurality of pixels Pix having such a configuration are arranged in a matrix.
Since each pixel Pix has the same configuration, for convenience of explanation, one pixel Pix will be representatively described below, and description of other pixels Pix will be omitted. In the following, the three cells 410 constituting the pixel Pix are referred to as a first cell 410A, a second cell 410B, and a third cell 410C, and the dispersion liquid 100 filled in the first cell 410A is used as the dispersion liquid. 100A, the dispersion 100 filled in the second cell 410B will be described as the dispersion 100B, and the dispersion 100 filled in the third cell 410C will be described as the dispersion 100C.

  As shown in FIG. 3, in the dispersion 100A filled in the first cell 410A, white particles (first particles) 5A forming white and red particles (second particles) 6A forming red are cyan. Is dispersed in a dispersion medium 7A. Further, the white particles 5A and the red particles 6A are electrophoretic particles charged to opposite poles. That is, one of the white particles 5A and the red particles 6A is positively charged, and the other particle is negatively charged. Further, the color of the dispersion medium 7A in which the white particles 5A and the red particles 6A are dispersed has a complementary color relationship with the color of the red particles 6A.

  The dispersion 100B filled in the second cell 410B is dispersed in a dispersion medium 7B in which white particles (first particles) 5B forming white and green particles (second particles) 6B forming green are magenta. It is a thing. Further, the white particles 5B and the green particles 6B are electrophoretic particles charged to opposite poles. That is, one of the white particles 5B and the green particles 6B is positively charged, and the other particle is negatively charged. Further, the color of the dispersion medium 7B in which the white particles 5B and the green particles 6B are dispersed has a complementary color relationship with the color of the green particles 6B.

Dispersion liquid 100C filled in third cell 410C is dispersed in dispersion medium 7C in which white particles (first particles) 5C forming white and blue particles (second particles) 6C forming blue are formed in yellow. It is a thing. Further, the white particles 5C and the blue particles 6C are electrophoretic particles charged to opposite poles. That is, one of the white particles 5C and the blue particles 6C is positively charged, and the other particle is negatively charged. The color of the dispersion medium 7C in which the white particles 5C and the blue particles 6C are dispersed has a complementary color relationship with the color of the blue particles 6C.
Dispersion of these electrophoretic particles (white particles 5A, 5B, 5C, red particles 6A, green particles 6B, and blue particles 6C; the same shall apply hereinafter) in the dispersion medium 7 (7A, 7B, and 7C) is, for example, a paint shaker method, One or two or more of ball mill method, media mill method, ultrasonic dispersion method, stirring dispersion method and the like can be used.

  As the dispersion medium 7 (7A, 7B and 7C), a material having low solubility in the base 401 and the lid 402 and having a relatively high insulating property is preferably used. Examples of the dispersion medium 7 include various types of water (for example, distilled water, pure water, etc.), alcohols such as methanol, cellosolves such as methyl cellosolve, esters such as methyl acetate, ketones such as acetone, pentane and the like. Aliphatic hydrocarbons (liquid paraffin), cyclohexane and other alicyclic hydrocarbons, benzene and other aromatic hydrocarbons, methylene chloride and other halogenated hydrocarbons, pyridine and other aromatic fluorinated rings, Nitriles such as acetonitrile, amides such as N, N-dimethylformamide, carboxylates or other various oils can be used, and these can be used alone or as a mixture.

  Among these, as the dispersion medium 7, an aliphatic hydrocarbon (liquid paraffin) or a material mainly composed of silicone oil is preferable. The dispersion medium 7 mainly composed of liquid paraffin or silicone oil is preferable because it has a high effect of suppressing aggregation of electrophoretic particles and has low affinity (low solubility) with the constituent material of the cell 410. Thereby, it can prevent or suppress more reliably that the display performance of the display apparatus 20 deteriorates with time. In addition, liquid paraffin or silicone oil is preferable from the viewpoint of excellent weather resistance and high safety because it does not have an unsaturated bond.

In the present embodiment, in order to color the dispersion media 7A, 7B, and 7C into cyan, magenta, and yellow, respectively, the dispersion media 7A, 7B, and 7C are, for example, anthraquinone dyes and azo dyes. Various dyes such as indigoid dyes are appropriately dissolved.
In addition, in the dispersion medium 7, for example, an electrolyte, a surfactant such as an alkenyl succinate (anionic or cationic), a metal soap, a resin material, a rubber material, an oil, a varnish, You may make it add various additives, such as charge control agents consisting of particles, such as a compound, dispersing agents, such as a silane coupling agent, a lubricant, and a stabilizer.

  The electrophoretic particles are particles that are charged and can be electrophoresed in the dispersion medium 7 by the action of an electric field. Any electrophoretic particles may be used as long as they have a charge. Although not particularly limited, at least one of pigment particles, resin particles, or composite particles thereof is preferably used. Is done. These particles have the advantage that they are easy to manufacture and the charge can be controlled relatively easily.

  Examples of the pigment constituting the pigment particles include black pigments such as aniline black, carbon black, titanium black and copper chromite, white pigments such as titanium oxide and antimony oxide, azo pigments such as monoazo, isoindolinone, Yellow pigments such as yellow lead, red pigments such as quinacridone red and chrome vermilion, blue pigments such as phthalocyanine blue and indanthrene blue, green pigments such as phthalocyanine green, etc. They 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.
The composite particles include, for example, those in which the surface of the pigment particles is coated with a resin material or other pigment, those in which the surface of the resin particles is coated with a pigment, or a mixture in which the pigment and the resin material are mixed at an appropriate composition ratio. The particle | grains comprised by these, etc. are mentioned.
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 include white particles 5A, 5B, It is suitably used as 5C.
The shape of the electrophoretic particles is not particularly limited, but is preferably spherical.

  In consideration of the dispersibility in the dispersion medium 7, the smaller electrophoretic particles are preferably used. Specifically, the average particle diameter is preferably about 10 nm or more and 500 nm or less. More preferably, it is about 20 nm or more and 300 nm or less. By setting the average particle diameter of the electrophoretic particles in the above range, aggregation of the electrophoretic particles and sedimentation in the dispersion medium 7 can be surely prevented and dispersed in the dispersion medium 7. Deterioration of display quality of the display device 20 can be suitably prevented.

  In the case of using two different types of particles as in the present embodiment, the average particle sizes of the two types of particles are made different. In particular, the average particle sizes of the white particles 5A, 5B, and 5C are changed to the red particles 6A and green. It is preferable to set larger than the average particle diameter of the particles 6B and the blue particles 6C. Thereby, the display contrast of the display device 20 can be further improved, and the holding characteristics can be improved. Specifically, the average particle diameter of the red particles 6A, the green particles 6B, and the blue particles 6C is about 20 nm to 100 nm, and the average particle diameter of the white particles 5A, 5B, and 5C is about 150 nm to 300 nm. preferable.

  Moreover, it is preferable that the specific gravity of the electrophoretic particles is set to be approximately equal to the specific gravity of the dispersion medium 7. Thereby, even after the application of the voltage between the electrodes 3 and 4 is stopped, the electrophoretic particles can stay in a certain position in the dispersion medium 7 for a long time. That is, a memory property can be given to the display device 20, and displayed information is held for a long time.

2. Driving method of display device (driving method of the present invention)
Such a display device 20 is driven as follows.
When a voltage is applied between the first electrode 3 and the second electrode 4 of the display device 20, an electric field is generated between them. In accordance with this electric field, the electrophoretic particles (white particles 5A, 5B, 5C, red particles 6A, green particles 6B, blue particles 6C) move (electrophoresis) toward one of the electrodes 3 and 4. Hereinafter, the case where positively charged particles are used as the white particles 5A, 5B, and 5C, and negatively charged particles are used as the red particles 6A, the green particles 6B, and the blue particles 6C will be representatively described.

  Further, the first cell 410A among the first cell 410A, the second cell 410B, and the third cell 410C will be described as a representative, and the second cell 410B and the third cell 410C will be described. Is omitted. In the following, it is assumed that the moving speeds of white particles 5A and red particles 6A (the moving distance of particles in the dispersion medium per unit time when a predetermined electric field is applied) are equal. In the following, driving at a predetermined temperature (for example, at room temperature) will be described. Further, it is assumed that the second electrode 4 is in a grounded state (0 V).

The first cell 410A has a white display state (first color display state) shown in FIG. 4A, a red display state (second color display state) shown in FIG. 4B, and (c). A black display state (third color display state) can be obtained. The white display state is a state in which white particles 5A are unevenly distributed on the second electrode 4 side, the red display state is a state in which red particles 6A are unevenly distributed on the second electrode 4 side, and the black display state is red. In this state, the particles 6A are dispersed in the dispersion 7A. In the black display state, it is preferable that the white particles 5A are unevenly distributed on the first electrode 3 side.
In the display device 20, at least switching between the white display state and the red display state, switching between the red display state and the black display state, and the black display state and the white display state are performed by a circuit formed on the circuit board (control device) 22. Can be switched. Hereinafter, these switching will be described.

-Switching between white display state and red display state-
When switching from the red display state to the white display state, the voltage V1 shown in FIG. 5A is applied to the first electrode 3 in the red display state. As a result, an electric field is generated between the first electrode 3 and the second electrode 4 such that the first electrode 3 side has a higher potential than the second electrode 4 side. By the action of this electric field, the white particles 5A move to the second electrode 4 side and are unevenly distributed on the second electrode 4, and the red particles 6A move to the first electrode 3 side to move to the first electrode 3 side. Is unevenly distributed. As a result, a white display state is established, and white is displayed on the display surface 121.
In the present specification, “uneven distribution” means that the plurality of white particles 5A (the same applies to the red particles 6A) substantially comes into contact with the inner wall of the first cell 410 and other particles. Are gathered in a state where they cannot move in the immediately preceding movement direction (the same applies hereinafter).

  Conversely, when switching from the white display state to the red display state, the voltage V2 shown in FIG. 5B is applied to the first electrode 3 in the white display state. As a result, an electric field is generated between the first electrode 3 and the second electrode 4 such that the first electrode 3 side is at a lower potential than the second electrode 4 side. By the action of this electric field, the white particles 5A move to the first electrode 3 side and are unevenly distributed on the first electrode 3, and the red particles 6A move to the second electrode 4 side to move to the second electrode 4 side. Is unevenly distributed. As a result, a red display state is established, and a red color is generated on the display surface 121.

The voltage V1 is a plus (+) voltage, has a rectangular waveform, and has a constant magnitude over time. Although the magnitude | size of the voltage V1 is not specifically limited, In this embodiment, it is set to + 15V. The application time of the voltage V1 to the first electrode 3 is such that the white particles 5A are moved from the second electrode 4 side to the first electrode 3 side in the first cell 410A (that is, the first cell 3). If it can be moved a distance equal to the thickness of 410A), it is not particularly limited, but the time required for the white particles 5A to move from the second electrode 4 side to the first electrode 3 side (that is, the first time) It is preferably approximately equal to or slightly longer than the time required to travel a distance equal to the thickness of cell 410A. Thereby, excessive voltage application to the 1st electrode 3 is prevented, and voltage application time can be optimized. Furthermore, the burning of the white particles 5A and the red particles 6A to the inner wall of the first cell 410A can be prevented or suppressed.
On the other hand, the voltage V2 is the same as the voltage V1 except that the polarity is different. That is, the voltage V2 is a minus (−) voltage, has a rectangular waveform, and has a constant magnitude over time. The magnitude of the voltage V2 is (−) 15V in the present embodiment. The application time of the voltage V2 to the first electrode 3 is the same as the application time of the voltage V1.

−Switching between red display state and black display state−
When switching from the red display state to the black display state, the voltage V3 shown in FIG. 5C is applied to the first electrode 3 in the red display state. The voltage V3 has a rectangular waveform, and the magnitude of the voltage is constant over time. The application time of the voltage V3 to the first electrode 3 is the same as the application time of the voltage V1.

Further, the magnitude (absolute value) of the voltage V3 is lower than the magnitude (absolute value) of the voltage V1, and is about ¼ or more and ½ or less of the magnitude (absolute value) of the voltage V1. preferable. In other words, the strength of the electric field generated between the first electrode 3 and the second electrode 4 by applying the voltage V3 to the first electrode 3 applies the voltage V1 to the first electrode 3. Accordingly, it is preferable that the intensity of the electric field generated between the first electrode 3 and the second electrode 4 is about ¼ or more and ½ or less. Thereby, as will be described later, a black display state in which black having a lower reflectance is displayed can be obtained. In the present embodiment, the magnitude of the voltage V3 is set to (+) 5V.
When such a voltage V3 is applied to the first electrode 3, the first electrode 3 side is at a higher potential than the second electrode 4 side between the first electrode 3 and the second electrode 4. An electric field is generated. By the action of this electric field, the white particles 5A move from the first electrode 3 side to the second electrode 4 side, and the red particles 6A move from the second electrode 4 side to the first electrode 3 side.

However, as described above, since the magnitude (absolute value) of the voltage V3 is smaller than the voltage V1, the white particles 5A reach the second electrode 4 even when the voltage V3 is applied for a time equal to the voltage V1. Similarly, the red particles 6 </ b> A do not reach the first electrode 3. As a result, as shown in FIG. 4C, the red particles 6A are dispersed on the second electrode 4 side in the first cell 410A and on the lower side (first electrode 3 side). The white particles 5A are dispersed. As a result, a black display state is established, and black, which is a mixed color of the color of the red particles 6A and the color of the dispersion medium 7A, is displayed on the display surface 121.
In the present specification, “dispersion” means that a plurality of white particles 5A (the same applies to red particles 6A) can be moved in the first cell 410A while being separated from each other, that is, in the immediately preceding movement direction. It is said that it is scattered substantially uniformly.

Here, when the voltage application time to the first electrode 3 is the same, the relationship between the magnitude of the applied voltage and the movement distance of the particles (white particles 5A and red particles 6A) is shown in FIGS. 6 (a) and 6 (b). Show. As can be seen from FIG. 6A, when the voltage application time is the same, the moving distance of the white particles 5A and the red particles 6A is proportional to the magnitude (absolute value) of the voltage.
By utilizing such a property, the magnitude of the voltage V3 is set to about １ ／ of the voltage V1, so that the red particles 6A are moved from the second electrode 4 to the first cell 410A in the black display state. The white particles 5A can be dispersed in the vicinity of a position separated from the second electrode 4 by about 2/3 of the thickness of the first cell 410A. Can do. Therefore, when the first cell 410A is viewed from the display surface 121 side, the white particles 5A can be effectively obscured by the red particles 6A, so that black with a lower reflectance can be displayed.

  On the contrary, when switching from the black display state to the red display state, the voltage V4 shown in FIG. 5D is applied to the first electrode 3 in the black display state. The voltage V4 is the same as the voltage V3 except that the polarity is different. That is, the voltage V4 is a minus (−) voltage, has a rectangular waveform, and has a constant magnitude over time. The magnitude of the voltage V4 is (−) 5V in the present embodiment. The application time of the voltage V4 to the first electrode 3 is equal to the application time of the voltage V1.

  When such a voltage V4 is applied to the first electrode 3, the first electrode 3 side is at a lower potential than the second electrode 4 side between the first electrode 3 and the second electrode 4. An electric field is generated. By the action of this electric field, the white particles 5A move from the dispersed state to the first electrode 3 side and are unevenly distributed on the first electrode 3, and the red particles 6A move from the dispersed state to the second electrode 4 side and move to the second electrode 4 side. The second electrode 4 is unevenly distributed. As a result, a red display state is established, and red is displayed on the display surface 121.

  Here, by setting the magnitude of the voltage V4 to about 1/3 of the magnitude of the voltage V2, the voltage V4 is dispersed in the vicinity of a position separated from the second electrode 4 by about 1/3 of the thickness of the first cell 410A. The red particles 6A can be moved to the second electrode 4 side by about 1/3 of the thickness of the first cell 410A, and similarly, the thickness of the first cell 410A from the first electrode 3 is increased. The white particles 5A dispersed in the vicinity of a position separated by about 1/3 can be moved to the first electrode 3 side by about 1/3 of the thickness of the first cell 410A. Therefore, it is possible to switch from the black display state to the red display state while preventing excessive voltage application.

-Switching between black display and white display-
When switching from the white display state to the black display state, the voltage V5 shown in FIG. 5E is applied to the first electrode 3 in the white display state. The voltage V5 has a rectangular waveform, and the magnitude of the voltage is constant over time. The application time of the voltage V3 to the first electrode 3 is equal to the application time of the voltage V1.

Further, the magnitude (absolute value) of the voltage V5 is lower than the magnitude (absolute value) of the voltage V1, and is higher than the magnitude (absolute value) of the voltage V3. Specifically, the magnitude (absolute value) of the voltage V5 is preferably about ½ or more and 3/4 or less of the magnitude (absolute value) of the voltage V1. In other words, the strength of the electric field generated between the first electrode 3 and the second electrode 4 by applying the voltage V5 to the first electrode 3 applies the voltage V1 to the first electrode 3. Accordingly, it is preferable that the intensity of the electric field generated between the first electrode 3 and the second electrode 4 is about ½ or more and 3/4 or less. Thereby, as will be described later, a black display state in which black having a lower reflectance is displayed can be obtained. In the present embodiment, the magnitude of the voltage V5 is set to (−) 10V.
When such a voltage V5 is applied to the first electrode 3, the first electrode 3 side is at a lower potential than the second electrode 4 side between the first electrode 3 and the second electrode 4. An electric field is generated. By the action of the electric field, the white particles 5A move from the second electrode 4 side to the first electrode 3 side, and the red particles 6A move from the first electrode 3 side to the second electrode 4 side.

  However, as described above, since the magnitude (absolute value) of the voltage V5 is smaller than the voltage V1, the white particles 5A reach the first electrode 3 even when the voltage V5 is applied for a time equal to the voltage V1. Similarly, the red particles 6 </ b> A do not reach the second electrode 4. As a result, as shown in FIG. 4C, the red particles 6A are dispersed on the second electrode 4 side in the first cell 410A and on the lower side (first electrode 3 side). The white particles 5A are dispersed. As a result, a black display state is established, and black is displayed on the display surface 121.

  Here, as can be seen from FIG. 6B, by setting the magnitude of the voltage V5 to about 2/3 of the voltage V1, the red particles 6A are separated from the second electrode 4 in the black display state. The white particles 5A can be dispersed in the vicinity of a position separated by about 1/3 of the thickness of one cell 410A, and the white particles 5A are located in the vicinity of a position separated by about 2/3 of the thickness of the first cell 410A from the second electrode 4. Can be dispersed. Therefore, when the first cell 410A is viewed from the display surface 121 side, the white particles 5A can be effectively obscured by the red particles 6A, so that black with a lower reflectance can be displayed. In addition, since the red display state can be the same color as the black display state (black having substantially the same reflectance), a clear image without display unevenness can be displayed.

  Conversely, when switching from the black display state to the white display state, the voltage V6 shown in FIG. 5F is applied to the first electrode 3 in the black display state. The voltage V6 is the same as the voltage V5 except that the polarity is different. That is, the voltage V5 is a (+) voltage, has a rectangular waveform, and has a constant magnitude over time. The application time of the voltage V4 to the first electrode 3 is equal to the application time of the voltage V1. In the present embodiment, the magnitude of the voltage V6 is set to (+) 10V.

  When such a voltage V6 is applied to the first electrode 3, the first electrode 3 side is at a higher potential than the second electrode 4 side between the first electrode 3 and the second electrode 4. An electric field is generated. By the action of this electric field, the white particles 5A move from the dispersed state to the second electrode 4 side and are unevenly distributed to the second electrode 4 side, and the red particles 6A move from the dispersed state to the first electrode 3 side. And unevenly distributed on the first electrode 3 side. As a result, a white display state is established, and white is displayed on the display surface 121.

  Here, by setting the magnitude of the voltage V6 to about 2/3 of the magnitude of the voltage V1, the voltage V6 is dispersed in the vicinity of a position separated from the second electrode 4 by about 2/3 of the thickness of the first cell 410A. The white particles 5A can be moved to the second electrode 4 side by about 2/3 of the thickness of the first cell 410A, and similarly, the thickness of the first cell 410A from the first electrode 3 is increased. Thus, the red particles 6A dispersed in the vicinity of a position separated by about 2/3 can be moved to the first electrode 3 side by about 2/3 of the thickness of the first cell 410A. Therefore, it is possible to switch from the black display state to the white display state while preventing excessive voltage application.

The driving method of the display device 20 using the first cell 410A has been described in detail above. According to such a driving method, since the voltage pattern to be applied to the first electrode 3 is selected according to the state immediately before the first cell 410A, the display state can be switched more efficiently. As a result, power saving driving can be achieved, and the white particles 5A and the red particles 6A can be effectively prevented or suppressed from being burned onto the inner wall of the first cell 410A.
In particular, in the present embodiment, the mobility of the white particles 5A and the red particles 6A is set equal, so the movement of the white particles 5A and the red particles 6A is controlled symmetrically in the thickness direction of the first cell 410A. Therefore, the display state of each color can be achieved more easily and reliably.

Note that the display state of the immediately preceding first cell 410A is the same in any of the white display state, the red display state, and the black display state (for example, when changing from the white display state to the white display state). In this case, the voltage as described above may not be applied to the first electrode 3. Thereby, power saving driving can be realized, and burn-in of the white particles 5A and the red particles 6A can be prevented.
Further, as shown in FIGS. 6A and 6B, the voltages V1 to V6 are all thresholds (Vmin) of the magnitude of the voltage (electric field) necessary for the migration of the white particles 5A and the red particles 6A. ) Is set higher.

  Next, color display in one pixel Pix will be described. Similar to the first cell 410A described above, the second cell 410B also has a white display state (first color display state), a green display state (second color display state), and a black display state (third Color display state) can be selected. Also in the third cell 410C, a white display state (first color display state), a blue display state (second color display state), and a black display state (third color display state) are selected. be able to.

  Therefore, in one pixel Pix, full color display can be performed by independently controlling (selecting) the display state of each cell 410A, 410B, 410C. For example, if (first cell 410A / second cell 410B / third cell 410C) is set to (red display state / green display state / white display state), a mixed color of red and green can be displayed. , (White display state / green display state / blue display state), a mixed color of green and blue can be displayed. Furthermore, a full color image can be displayed on the display surface 121 by selecting a display color for each pixel Pix.

<Second Embodiment>
FIG. 7 is a diagram illustrating a voltage applied to the first electrode of the display device illustrated in FIG. 1.
Hereinafter, the second embodiment will be described with a focus on differences from the above-described embodiment, and description of similar matters will be omitted.
The display device (display sheet driving method, control device) according to the second embodiment of the present invention is the same as the display device of the first embodiment, except that the pattern of the voltage applied to the first cell 410A is different. . In addition, the same code | symbol is attached | subjected to the structure similar to 1st Embodiment mentioned above.
The display device of the present embodiment has the same configuration as the display device 20 of the first embodiment. Therefore, a driving method of the display device 20 will be described below as a representative example of the first cell 410A.

-Switching between white display state and red display state-
When switching from the red display state to the white display state, the voltage V1 ′ shown in FIG. 7A is applied to the first electrode 3 in the red display state. As a result, an electric field is generated between the first electrode 3 and the second electrode 4 such that the first electrode 3 side has a higher potential than the second electrode 4 side. By the action of this electric field, the white particles 5A move to the second electrode 4 side and are unevenly distributed on the second electrode 4, and the red particles 6A move to the first electrode 3 side to move to the first electrode 3 side. Is unevenly distributed. As a result, a white display state is established, and white is displayed on the display surface 121.

  Conversely, when switching from the white display state to the red display state, the voltage V2 'shown in FIG. 7B is applied to the first electrode 3 in the white display state. As a result, an electric field is generated between the first electrode 3 and the second electrode 4 such that the first electrode 3 side is at a lower potential than the second electrode 4 side. By the action of this electric field, the white particles 5A move to the first electrode 3 side and are unevenly distributed on the first electrode 3, and the red particles 6A move to the second electrode 4 side to move to the second electrode 4 side. Is unevenly distributed. As a result, a red display state is established, and red is displayed on the display surface 121.

The voltage V1 ′ is a plus (+) voltage, and is a rectangular pulse wave whose magnitude changes with time. Although the magnitude | size of voltage V1 'is not specifically limited, In this embodiment, it is + 15V. The application time of the voltage V1 ′ to the first electrode 3 (number of pulse waves applied) is such that the white particles 5A are moved from the second electrode 4 side to the first electrode 3 side in the first cell 410. If it can be made, it is not particularly limited, but the time required for the white particles 5A to move from the second electrode 4 side to the first electrode 3 side (that is, a distance equal to the thickness of the first cell 410) is moved. Preferably approximately equal to or slightly longer than the time required for Thereby, excessive voltage application to the 1st electrode 3 is prevented, and voltage application time can be optimized.
On the other hand, the voltage V2 ′ is the same as the voltage V1 ′ except that the polarity is different. That is, the voltage V2 ′ is a minus (−) voltage, and is a rectangular pulse wave whose magnitude changes with time. The magnitude of the voltage V2 ′ is (−) 15V in the present embodiment. The application time of the voltage V2 ′ to the first electrode 3 is equal to the application time of the voltage V1 ′.

−Switching between red display state and black display state−
When switching from the red display state to the black display state, the voltage V3 ′ shown in FIG. 7C is applied to the first electrode 3 in the red display state. The voltage V3 ′ is a pulse wave having the same waveform (size and period) as the voltage V1 ′.
The application time of the voltage V3 ′ to the first electrode 3 is shorter than the application time of the voltage V1 ′ to the first electrode 3. Specifically, the application time of voltage V3 ′ (that is, the number of applied pulse waves) is preferably about ¼ or more and ½ or less of the application time of voltage V1 ′. In other words, when the voltage V3 ′ is applied to the first electrode 3 and the electric field generated between the first electrode 3 and the second electrode 4 acts, the voltage V1 ′ is applied to the first electrode 3. It is preferable that the electric field generated between the first electrode 3 and the second electrode 4 is applied to ¼, and is ¼ or more and ½ or less of the time during which the electric field acts. Thereby, as will be described later, a black display state in which black having a lower reflectance is displayed can be obtained. In the present embodiment, the application time of the voltage V3 ′ is set to about 1/3 of the voltage V1 ′.
When such a voltage V3 ′ is applied to the first electrode 3, the first electrode 3 side has a higher potential than the second electrode 4 side between the first electrode 3 and the second electrode 4. An electric field is generated. By the action of this electric field, the white particles 5A move from the first electrode 3 side to the second electrode 4 side, and the red particles 6A move from the second electrode 4 side to the first electrode 3 side.

  However, as described above, since the application time of the voltage V3 ′ is shorter than that of the voltage V1 ′, the white particles 5A do not reach the second electrode 4, and the red particles 6A are also the first electrode 3 similarly. Not reach. As a result, as shown in FIG. 4C, the red particles 6A are dispersed on the second electrode 4 side in the first cell 410A and on the lower side (first electrode 3 side). The white particles 5A are dispersed. As a result, a black display state is established, and black is displayed on the display surface 121.

Here, when the voltage applied to the first electrode 3 is the same, the moving distance of the white particles 5A and the red particles 6A is proportional to the voltage application time. By utilizing such a property, the application time of the voltage V3 ′ is set to about 1/3 of the voltage V1 ′, so that the red particles 6A are moved from the second electrode 4 to the first electrode in the black display state. The white particles 5A can be dispersed in the vicinity of a position separated by about 1/3 of the thickness of the cell 410A, and the white particles 5A are dispersed in the vicinity of a position separated by about 2/3 of the thickness of the first cell 410A from the second electrode 4. Can be made. Therefore, when the first cell 410A is viewed from the display surface 121 side, the white particles 5A can be effectively obscured by the red particles 6A, so that black with a lower reflectance can be displayed.
Conversely, when switching from the black display state to the red display state, the voltage V4 ′ shown in FIG. 7D is applied to the first electrode 3 in the black display state. The voltage V4 ′ is a pulse wave having the same waveform (size and period) as the voltage V2 ′. The application time of the voltage V4 ′ to the first electrode 3 is the same as the voltage V3 ′.

  When such a voltage V 4 ′ is applied to the first electrode 3, the first electrode 3 side has a lower potential than the second electrode 4 side between the first electrode 3 and the second electrode 4. An electric field is generated. By the action of this electric field, the white particles 5A move from the dispersed state to the first electrode 3 side and are unevenly distributed on the first electrode 3, and the red particles 6A move from the dispersed state to the second electrode 4 side and move to the second electrode 4 side. The second electrode 4 is unevenly distributed. As a result, a red display state is established, and a red color is generated on the display surface 121.

  By setting the application time of the voltage V4 ′ to about 1/3 of the magnitude of the voltage V2 ′, the voltage V4 ′ is dispersed in the vicinity of a position separated from the second electrode 4 by about 1/3 of the thickness of the first cell 410A. The red particles 6A can be moved to the second electrode 4 side by about 1/3 of the thickness of the first cell 410A. Similarly, the thickness of the first cell 410A from the first electrode 3 is increased. The white particles 5A dispersed in the vicinity of a position separated by about 1/3 can be moved to the first electrode 3 side by about 1/3 of the thickness of the first cell 410A. Therefore, it is possible to switch from the black display state to the red display state while preventing excessive voltage application.

-Switching between black display and white display-
When switching from the white display state to the black display state, the voltage V5 ′ shown in FIG. 7E is applied to the first electrode 3 in the white display state. The voltage V5 ′ is a pulse wave having the same waveform (size and period) as the voltage V2 ′.
The application time of the voltage V5 ′ to the first electrode 3 is shorter than the application time of the voltage V2 ′ and longer than the application time of the voltage V4 ′. Specifically, the application time of voltage V5 ′ (that is, the number of applied pulse waves) is preferably about ½ or more and 3/4 or less of the application time of voltage V2 ′. In other words, when the voltage V5 ′ is applied to the first electrode 3 and the electric field generated between the first electrode 3 and the second electrode 4 acts, the voltage V2 ′ is applied to the first electrode 3. It is preferable that the electric field generated between the first electrode 3 and the second electrode 4 is applied to ½, and is ½ or more and ¾ or less of the time during which the electric field acts. Thereby, as will be described later, a black display state in which black having a lower reflectance is displayed can be obtained. In the present embodiment, the application time of the voltage V5 ′ is set to about 2/3 of the voltage V2 ′.
When such a voltage V5 ′ is applied to the first electrode 3, the first electrode 3 side has a lower potential than the second electrode 4 side between the first electrode 3 and the second electrode 4. An electric field is generated. By the action of the electric field, the white particles 5A move from the second electrode 4 side to the first electrode 3 side, and the red particles 6A move from the first electrode 3 side to the second electrode 4 side.

  However, as described above, since the application time of the voltage V5 ′ is shorter than the voltage V2 ′, the white particles 5A are applied to the first electrode 3 even when the voltage V5 ′ having the same waveform as the voltage V2 ′ is applied. Similarly, the red particles 6 </ b> A do not reach the second electrode 4. As a result, as shown in FIG. 4C, the red particles 6A are dispersed on the second electrode 4 side in the first cell 410A and on the lower side (first electrode 3 side). The white particles 5A are dispersed. As a result, a black display state is established, and black is displayed on the display surface 121.

By setting the magnitude of the voltage V5 ′ to about 2/3 of the voltage V2 ′, the red particles 6A are removed from the second electrode 4 to 1/3 of the thickness of the first cell 410A in the black display state. The white particles 5A can be dispersed in the vicinity of a position separated from the second electrode 4 by about 2/3 of the thickness of the first cell 410A. Therefore, when the first cell 410A is viewed from the display surface 121 side, the white particles 5A can be effectively obscured by the red particles 6A, so that black with a lower reflectance can be displayed. In addition, since the red display state can be the same color as the black display state (black having substantially the same reflectance), a clear image without display unevenness can be displayed.
Conversely, when switching from the black display state to the white display state, the voltage V6 ′ shown in FIG. 7F is applied to the first electrode 3 in the black display state. The voltage V6 ′ is a pulse wave having the same waveform (size and period) as the voltage V1 ′. The application time of the voltage V6 ′ to the first electrode 3 is the same as the voltage V5 ′.

  When such a voltage V 6 ′ is applied to the first electrode 3, the first electrode 3 side has a higher potential than the second electrode 4 side between the first electrode 3 and the second electrode 4. An electric field is generated. By the action of this electric field, the white particles 5A move from the dispersed state to the second electrode 4 side and are unevenly distributed to the second electrode 4 side, and the red particles 6A move from the dispersed state to the first electrode 3 side. And unevenly distributed on the first electrode 3 side. As a result, a white display state is established, and white is displayed on the display surface 121.

  Here, by setting the application time of the voltage V6 ′ to about 2/3 of the application time of the voltage V1 ′, in the vicinity of a position separated from the second electrode 4 by about 2/3 of the thickness of the first cell 410A. The dispersed white particles 5A can be moved to the second electrode 4 side by about 2/3 of the thickness of the first cell 410A. Similarly, from the first electrode 3 to the first cell 410A, The red particles 6A dispersed in the vicinity of a position separated by about 2/3 of the thickness can be moved to the first electrode 3 side by about 2/3 of the thickness of the first cell 410A. Therefore, it is possible to switch from the black display state to the white display state while preventing excessive voltage application.

The driving method of the display device 20 using the first cell 410A has been described in detail above. According to such a driving method, since the voltage pattern to be applied to the first electrode 3 is selected according to the state immediately before the first cell 410A, the display state can be switched more efficiently. As a result, power saving driving can be achieved, and the white particles 5A and the red particles 6A can be effectively prevented or suppressed from being burned onto the inner wall of the first cell 410A.
In the present embodiment, the above-described driving is realized by controlling the voltage application time. However, according to this, for example, the driving method for controlling the magnitude of the voltage as in the first embodiment. Thus, the control device can be simplified. Specifically, when controlling the magnitude of the voltage as in the first embodiment, it is necessary to provide a booster circuit or the like, but in this embodiment, it is not necessary to provide such a circuit. Configuration is simplified.

<Third Embodiment>
FIG. 8 is a cross-sectional view showing a black display state of the display device.
Hereinafter, the third embodiment will be described with a focus on differences from the above-described embodiment, and description of similar matters will be omitted.
In the display device (display sheet driving method and control device) according to the third embodiment of the present invention, the mobility of the white particles 5A, 5B, and 5C is the mobility of the red particles 6A, the green particles 6B, and the blue particles 6C. It is the same as that of the display apparatus of 1st Embodiment except being larger than this. In addition, the same code | symbol is attached | subjected to the structure similar to 1st Embodiment mentioned above.
The display device of the present embodiment has the same configuration as the display device 20 of the first embodiment. Therefore, in the following, a driving method of the display device 20 will be described using the first cell 410A as a representative.

The mobility (migration speed) of the white particles 5A is set to be larger than the mobility of the red particles 6A. Specifically, the mobility of the white particles 5A is preferably at least twice that of the red particles 6A. Thereby, black of a lower reflectance can be displayed by switching from a white display state to a black display state.
Specifically, from the white display state, the red particles 6A are moved from the first electrode 3 side to the second electrode 4 side, and the red particles 6A are moved to the second electrode 4 side in the first cell 410A. In the dispersed state, as shown in FIG. 8A, the white particles 5A have already moved from the second electrode 4 side to the first electrode 3 side and gathered at the first electrode 3. Thereby, it can prevent more effectively that the color of the white particle 5A is further mixed with the black which is a mixed color of the color of the red particle 6A and the color of the dispersion medium 7A. Therefore, black with a lower reflectance can be displayed in the black display state.

On the other hand, an attempt is made to switch from the red display state to the black display state, the red particles 6A are moved from the second electrode 4 side to the first electrode 3 side, and the red particles 6A are the second electrodes in the first cell 410A. As shown in FIG. 8 (b), the white particles 5A have already reached the second electrode 4 side, and the color of the red particles 6A and the color of the dispersion medium 7A are obtained. There is a possibility that the color of the white particles 5A is further mixed with black, which is a mixed color, and black with low reflectance cannot be displayed.
Therefore, in this embodiment, when switching from the red display state to the black display state, the white display state is temporarily passed, that is, after the red display state is changed to the white display state, the black display state is driven. Is preferred. Thereby, since black with a lower reflectance can be displayed, high contrast can be exhibited.

<Fourth embodiment>
FIG. 9 is a cross-sectional view showing a black display state of the display device.
Hereinafter, the fourth embodiment will be described with a focus on differences from the above-described embodiment, and description of similar matters will be omitted.
In the display device (display sheet driving method, control device) according to the fourth embodiment of the present invention, the mobility of the white particles 5A, 5B, and 5C is the mobility of the red particles 6A, the green particles 6B, and the blue particles 6C. It is the same as that of the display apparatus of 1st Embodiment except being larger than this. In addition, the same code | symbol is attached | subjected to the structure similar to 1st Embodiment mentioned above.
The display device of the present embodiment has the same configuration as the display device 20 of the first embodiment. Therefore, in the following, a driving method of the display device 20 will be described using the first cell 410A as a representative.

The mobility (migration speed) of the white particles 5A is set lower than the mobility of the red particles 6A. Specifically, the mobility of the white particles 5A is set to ½ or less of the mobility of the red particles 6A. Thereby, black of a lower reflectance can be displayed by switching from a red display state to a black display state.
Specifically, the red particles 6A are moved from the second electrode 4 side to the first electrode 3 side from the red display state, and the red particles 6A are moved to the second electrode 4 side in the first cell 410A. In the dispersed state, as shown in FIG. 9A, the white particles 5A are still gathered on the first electrode 3 side. Thereby, it can prevent more effectively that the color of the white particle 5A is further mixed with the black which is a mixed color of the color of the red particle 6A and the color of the dispersion medium 7A. Therefore, black with a lower reflectance can be displayed in the black display state.

On the other hand, an attempt is made to switch from the white display state to the black display state, the red particles 6A are moved from the first electrode 3 side to the second electrode 4 side, and the red particles 6A are the second electrodes in the first cell 410A. As shown in FIG. 9B, the white particles 5A are still gathered on the second electrode 4 side, and the color of the red particles 6A and the color of the dispersion medium 7A are obtained. There is a possibility that the color of the white particles 5A is further mixed with black, which is a mixed color, and black with low reflectance cannot be displayed.
Therefore, in the present embodiment, when switching from the white display state to the black display state, the red display state is temporarily passed through, that is, the white display state is changed to the red display state and then the black display state is driven. Is preferred. Thereby, since black with a lower reflectance can be displayed, high contrast can be exhibited.

<Fifth Embodiment>
FIG. 10 is a sectional view showing a fifth embodiment of the display device of the present invention.
Hereinafter, the fifth embodiment will be described with a focus on differences from the above-described embodiments, and description of similar matters will be omitted.
The display device according to the fifth embodiment of the present invention is the same as the display device of the first embodiment, except that the display sheet and the control device are formed separately. In addition, the same code | symbol is attached | subjected to the structure similar to 1st Embodiment mentioned above.

  As illustrated in FIG. 10, the display device 20A includes a display sheet 21A and a control device 22A. 21 A of display sheets are the board | substrate 12 provided with the 2nd electrode 4 provided in the lower surface of the flat base 2 and the base 2, and several 1st provided in the upper surface of the flat base 81 and the base 81. A substrate 8 including the electrode 3 and a display layer 400 provided between the substrates 12 and 8 are provided. The base 81 is provided with a circuit (not shown). For example, the circuit includes a plurality of TFTs provided corresponding to the first electrodes 3 and a plurality of gate lines formed corresponding to the TFTs. And a plurality of data lines, a gate driver that applies a predetermined voltage to the gate lines, and a data driver that applies a predetermined voltage to the data lines.

The control device 22A is used by being connected to the display sheet 21A, and controls the driving of the gate driver and the data driver that the display sheet 21A has. Such a control device 22A includes a CPU 221A, a display sheet controller 222A, and a drive waveform generator 223A. The display sheet controller 222A controls the drive of the gate driver and the data driver so that the voltage (waveform, application time, voltage value, etc.) generated by the drive waveform generator 223A is applied to a predetermined gate line and data line. To do. Further, the CPU 221A controls driving of the display sheet controller 222A.
According to such a configuration, a desired image can be displayed on the display sheet 21A by the control device 22A configured separately from the display sheet 21A.

  Each of the display devices 20 described above can be incorporated into various electronic devices. As an electronic apparatus of the present invention provided with an electrophoretic display device, for example, 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, Examples include a word processor, a personal computer, a workstation, a videophone, a POS terminal, and a device equipped with a touch panel.

Of these electronic devices, an electronic paper will be described as an example for specific description.
FIG. 11 is a perspective view showing an embodiment when the electronic apparatus of the present invention is applied to electronic paper.
An electronic paper 600 shown in FIG. 11 includes a main body 601 composed of a rewritable sheet having the same texture and flexibility as paper, and a display unit 602. In such electronic paper 600, the display unit 602 includes the display device 20 as described above.

Next, an embodiment when the electronic apparatus of the present invention is applied to a display will be described.
FIG. 12 is a diagram showing an embodiment when the electronic apparatus of the present invention is applied to a display. Among these, (a) in FIG. 12 is a sectional view and (b) is a plan view.
A display (display device) 800 shown in FIG. 12 includes a main body 801 and an electronic paper 600 that is detachably attached to the main body 801. The electronic paper 600 has the same configuration as described above, that is, the configuration shown in FIG.

  The main body 801 has an insertion port 805 into which the electronic paper 600 can be inserted on its side (right side in FIG. 12A), and two pairs of conveying rollers 802a and 802b are provided inside. Yes. When the electronic paper 600 is inserted into the main body 801 through the insertion port 805, the electronic paper 600 is installed in the main body 801 in a state of being sandwiched between the pair of conveyance rollers 802a and 802b.

  A rectangular hole 803 is formed on the display surface side of the main body 801 (the front side in FIG. 12B), and a transparent glass plate 804 is fitted in the hole 803. . Thereby, the electronic paper 600 installed in the main body 801 can be viewed from the outside of the main body 801. That is, in the display 800, the display surface is configured by visually recognizing the electronic paper 600 installed in the main body 801 on the transparent glass plate 804.

Further, a terminal portion 806 is provided at the leading end of the electronic paper 600 in the insertion direction (left side in FIG. 12A), and the electronic paper 600 is installed in the main body 801 inside the main body 801. A socket 807 to which the terminal portion 806 is connected in the state is provided. A controller 808 and an operation unit 809 are electrically connected to the socket 807.
In such a display 800, the electronic paper 600 is detachably installed on the main body 801, and can be carried and used while being detached from the main body 801. This improves convenience.

The display sheet driving method, the control device, the display device, and the electronic apparatus according to the present invention have been described based on the illustrated embodiment. However, the present invention is not limited to this, and the configuration of each part is the same. It can be replaced with any configuration having the above function. In addition, any other component may be added to the present invention. Moreover, you may combine each embodiment suitably.
In the first embodiment described above, each display state is switched by controlling the magnitude of the voltage. In the second embodiment described above, each display state is switched by controlling the voltage application time. However, these may be combined.

  For example, in the first cell, a voltage applied to the first electrode for switching between the white display state and the red display state, and a voltage applied to the first electrode for switching between the white display state and the black display state. In order to switch between the red display state and the black display state, the voltage applied to the first electrode may be set to have a smaller magnitude (absolute value) and a shorter application time. As a result, more precise control is possible and a higher quality image can be displayed.

Further, in the above-described embodiment, one pixel is composed of three cells, and a configuration capable of full color display has been described. However, one pixel may be composed of one cell. That is, a display device capable of displaying three colors of white, black, and one other color (second particle color) may be used.
In the above-described embodiment, white particles (first particles) that form white and red particles (second particles) that form red form cyan as the dispersion filled in the first cell. Using a dispersion in a dispersion medium, a white particle (first particle) forming white and a red particle (second particle) forming green are magenta as a dispersion filled in the second cell. As a dispersion liquid filled in the third cell, a white particle (first particle) forming white and red particles (second particle) forming blue are used as a dispersion liquid filled in the third cell. Although the structure using what was disperse | distributed to the dispersion medium which comprises is demonstrated, it is not limited to this. That is, as a dispersion liquid filled in the first cell, white particles (first particles) forming white and red particles (second particles) forming cyan are dispersed in a dispersion medium forming red. As a dispersion filled in the second cell, white particles (first particles) forming white and red particles (second particles) forming magenta are dispersed in a dispersion medium forming green. As a dispersion filled in the third cell, white particles (first particles) forming white and red particles (second particles) forming yellow are dispersed in a dispersion medium forming blue. It is good also as a structure using what was done. Also by this, a display device capable of full color display can be obtained.

  In the above-described embodiment, the display device having a configuration in which the dispersion liquid is filled in the cell (so-called partition wall type) has been described. However, the present invention is not limited to this. It may be a configured microcapsule type display device. The microcapsule type display device encloses, for example, a dispersion liquid in which white particles forming a white color (first particles) and red particles forming a red color (second particles) are dispersed in a cyan dispersion medium. A second microcapsule, a white particle (first particle) that forms white, and a red particle (second particle) that forms green are dispersed in a magenta dispersion medium. A third microcapsule enclosing a dispersion liquid in which a microcapsule, white particles forming a white color (first particle), and red particles forming a blue color (second particle) are dispersed in a yellow dispersion medium It can be obtained by preparing and applying these to a predetermined region by, for example, an ink jet method.

  DESCRIPTION OF SYMBOLS 1 ... Base 2 ... Base 3 ... 1st electrode 4 ... 2nd electrode 5 ... 1st particle 5A, 5B, 5C ... White particle 6 ... 2nd particle 6A ... Red particle 6B ... Green particles 6C ... Blue particles 7, 7A, 7B, 7C ... Dispersion medium 8 ... Substrate 81 ... Base 100, 100A, 100B, 100C ... Dispersion liquid 11 ... Counter substrate 12 ... Substrate 121 Display surface 20, 20A Display device 21, 21A Display sheet 22, 22A Circuit board 221A CPU 222A Display sheet controller 223A Drive waveform generator 400 Display layer 401 Base 401a... Recess 402... Lid 410... Cell 410A... First cell 410B ... Second cell 410C ... Third cell 600 ... Electronic paper 601 ... Main body 602 ... Display unit 800 ... Display 801 ... Main body 802a, 802b ... Conveying roller pair 803 ... Hole 804 ... Transparent glass plate 805 ... Insertion slot 806 ... Terminal 807 ... Socket 808 …… Controller 809 …… Operation unit V1 to V6, V1 'to V6' ... Voltage

Claims (9)

The first particles that are white and are positively or negatively charged and the second particles that are different in color from the first particles and are charged to the opposite pole of the first particles are the colors of the second particles. And a display sheet driving method having a display layer filled with a dispersion liquid dispersed in a dispersion medium of a color complementary to each other,
The display sheet causes the first particles to be unevenly distributed on the display surface side provided on one side of the display layer by applying an electric field to the display layer, and the color of the first particles on the display surface. A second color display state in which the second particles are unevenly distributed on the display surface side of the display layer and the color of the second particles is displayed on the display surface; Taking one of the third color display states in which the second particles are dispersed in a dispersion medium to display a mixed color of the second particles and the dispersion medium on the display surface; Can
In order to switch between the first color display state and the third color display state rather than an electric field applied to the display layer to switch between the first color display state and the second color display state. At least one of an electric field applied to the display layer and an electric field applied to the display layer to switch between the second color display state and the third color display state; A display sheet driving method characterized by satisfying the above.   In order to switch between the second color display state and the third color display state rather than an electric field applied to the display layer to switch between the first color display state and the third color display state. A display sheet driving method characterized by satisfying at least one of a small electric field applied to the display layer and a short operation time.   The display sheet driving method according to claim 2, wherein the mobility of the first particles in the dispersion medium is different from the mobility of the second particles in the dispersion medium.   The display sheet driving method according to claim 2, wherein the mobility of the first particles in the dispersion medium is equal to the mobility of the second particles in the dispersion medium.   5. The display sheet driving method according to claim 1, wherein when switching from the first color display state to the third color display state, the display sheet passes through the second color display state.   5. The display sheet driving method according to claim 1, wherein when switching from the second color display state to the third color display state, the display sheet passes through the first color display state. The first particles that are white and are positively or negatively charged and the second particles that are different in color from the first particles and are charged to the opposite pole of the first particles are the colors of the second particles. And having a display layer filled with a dispersion liquid dispersed in a dispersion medium of a color complementary to each other, and applying an electric field to the display layer, the first particles are placed on one side of the display layer. A first color display state in which the color of the first particles is displayed on the display surface by being unevenly distributed on the display surface side provided in the display surface, and the second particles are unevenly distributed on the display surface side of the display layer. A second color display state in which the color of the second particles is displayed on the display surface, and the second particles are dispersed in the dispersion medium, and the second particles and the dispersion medium are mixed on the display surface. Driving the display sheet that can take any one of the third color display states for displaying colors A Gosuru control device,
In order to switch between the first color display state and the third color display state rather than an electric field applied to the display layer to switch between the first color display state and the second color display state. At least one of an electric field applied to the display layer and an electric field applied to the display layer to switch between the second color display state and the third color display state; A control device that controls driving of the display sheet to satisfy the condition. The first particles that are white and are positively or negatively charged and the second particles that are different in color from the first particles and are charged to the opposite pole of the first particles are the colors of the second particles. And a display layer filled with a dispersion liquid dispersed in a dispersion medium of a color complementary to each other,
By applying an electric field to the display layer, the first particles are unevenly distributed on the display surface side provided on one side of the display layer, and the color of the first particles is displayed on the display surface. The color display state, the second particles are unevenly distributed on the display surface side of the display layer, and the second color display state displays the color of the second particles on the display surface. It can take any one of the third color display states in which the second particles are dispersed to display the mixed color of the second particles and the dispersion medium on the display surface,
In order to switch between the first color display state and the third color display state rather than an electric field applied to the display layer to switch between the first color display state and the second color display state. At least one of an electric field applied to the display layer and an electric field applied to the display layer to switch between the second color display state and the third color display state; A display device characterized by satisfying.   An electronic apparatus comprising the display device according to claim 8.

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