JP2009145419A - Display medium, writing device, and display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display medium, a writing device and a display device capable of suppressing decrease in display density. <P>SOLUTION: The display medium 12 is configured to have a hollow structure 26 that includes: first spaces 26A arranged in at least the plane direction on a surface of a display substrate 18, the surface opposing to a back substrate 20; and connection holes 26B having hole diameters varying by imparting electric field stimulation as a first stimulus, the connection holes connecting the first spaces 26A with the outside in at least an open state with the largest hole diameter, and allowing first particles 36 to pass through from the outside to enter the first space 26A. After the connection holes 26B are opened by the first stimulus such as electricity, light, heat or pH, a voltage to induce electrophoresis of the first particles 36 toward the display substrate 18 is applied to allow the first particles 36 to reach into the first spaces 26A of the hollow structure 26, and further, the first stimulus is imparted to close the connection holes 26B. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a display medium, a writing device, and a display device.

  2. Description of the Related Art Conventionally, as a sheet-like display element that can be rewritten repeatedly, a display medium that encloses charged particles between substrates and performs display using movement of the particles between the substrates is known (for example, patents). Reference 1, Patent Document 2, Patent Document 3, and Patent Document 4).

  According to the technique of Patent Document 1, a porous layer having pores through which electrophoretic particles can move is provided between a pair of substrates, and a dispersion medium in which the electrophoretic particles are dispersed is enclosed between the substrates. The porous layer has a structure colored in two or more colors different from the electrophoretic particles, and the porous layer is shielded or released by the movement of the electrophoretic particles, so that The multicolor display is performed by visually recognizing the colored portion.

  Further, according to the techniques of Patent Document 2, Patent Document 3, and Patent Document 4, a spherical body is filled between the substrates, and display is performed by moving the electrophoretic particles through the spherical bodies. Yes. The spherical body functions as a shielding material that hinders the visual recognition of the electrophoretic particles, and the spherical body is configured to have a brightness and color different from those of the electrophoretic particles, so that the particles that have moved to the back substrate side are displayed on the display surface. It is prevented from being visually recognized from the side to suppress a decrease in contrast, and enables multicolor display.

In such a display medium, particles move when an electric field is formed between the substrates, and the particles do not move when there is no electric field. It has become. However, there are cases where particles that have moved during the formation of an electric field move even in the absence of an electric field, and there has been a concern about a decrease in image retention.
JP 2005-156808 A Japanese Patent Laid-Open No. 2003-186062 JP 2001-242492 A Japanese Patent Publication No. 50-152120

  It is an object of the present invention to provide a display medium, a writing device, and a display device that can suppress a decrease in display density.

The above problem is solved by the following means. That is,
According to the first aspect of the present invention, there is provided a display substrate that transmits at least light in a visible light region, a back substrate disposed to face the display substrate with a gap, and a space between the display substrate and the back substrate. A first particle that moves between the display substrate and the back substrate in response to the electric field formed between the substrate and the display substrate and the back substrate; A first space that is arranged at least in the surface direction on the surface of the display substrate facing the back substrate and in which at least a plurality of the first particles can exist, and the application of the first stimulus Because the hole diameter changes and the first space communicates with the outside at least in the opening state in which the hole diameter is the largest, and at least in the opening state, the first particles enter the first space from the outside. In The display medium includes a connection hole through which the first particle passes, and a hollow structure that transmits at least light in the visible light region.

  The invention according to claim 2 is the display medium according to claim 1, wherein the hole diameter of the connection hole is larger than the volume average primary particle diameter of the first particle in the opened state.

  The invention according to claim 3 is characterized in that the hole diameter of the connection hole is 2/3 or less of the hole diameter of the open state in the closed state where the hole diameter is the smallest. Display media.

  The invention according to claim 4 is characterized in that the hole diameter of the connecting hole is smaller than the volume average primary particle diameter of the first particle in the closed state where the hole diameter is the smallest. It is a display medium given in any 1 paragraph.

  The invention according to claim 5 is characterized in that the hole diameter of the connecting hole is smaller than the diameter of the first space at least in the opened state. It is a display medium.

  The invention according to claim 6 is characterized in that the connection hole further communicates with the adjacent first space at least in the opened state. It is a display medium.

  The invention according to claim 7 is characterized in that the first stimulus is any one of an electric field, light, heat, and pH. It is a display medium.

  The invention according to claim 8 is characterized in that the first spaces of the hollow structure are regularly arranged at least in the surface direction of the display substrate. The display medium according to Item 1.

  In the invention according to claim 9, a plurality of the first spaces of the hollow structure body are arranged in a direction in which the display substrate and the substrate face each other, and the connection holes are adjacent at least in the open state. The display medium according to claim 1, wherein the display medium communicates with each other.

  The invention according to claim 10 is characterized in that the first space of the hollow structure is regularly arranged in the facing direction of the display substrate and the back substrate. It is a display medium as described in above.

  According to an eleventh aspect of the present invention, the first space can hold at least a plurality of the first particles by aggregating the first particles by the repulsive force between the first particles and the inner wall. The display medium according to claim 1, wherein the display medium is a display medium.

  The invention according to claim 12 is the display medium according to any one of claims 1 to 10, wherein the first particles are aggregated or dispersed by applying a second stimulus. .

  The invention according to claim 13 is the display medium according to claim 12, wherein the second stimulus is any one of an electric field, light, and heat.

  The invention according to claim 14 is the display medium according to claim 12 or claim 13, wherein the second stimulus is the same stimulus as the first stimulus.

  The invention according to claim 15 is characterized in that the first particles include a plurality of types of particles having different absolute values of voltages necessary for moving in accordance with an electric field and colored in different colors. The display medium according to any one of claims 1 to 14.

  The invention according to claim 16 is provided between the display substrate and the back substrate, and has a first hole through which the first particles pass at least in the facing direction of the display substrate and the back substrate. The display medium according to any one of claims 1 to 15, further comprising an intermediate layer having a color different from that of the first particles.

  The invention according to claim 17 is the display medium according to claim 16, wherein the intermediate layer is an aggregate of a plurality of second particles.

  The invention according to claim 18 is the display medium according to claim 16, wherein the intermediate layer is a nonwoven fabric.

  The invention according to claim 19 is the display medium according to any one of claims 16 to 18, wherein the intermediate layer is white.

  The invention according to claim 20 further comprises a constraining layer that is laminated on the side of the back substrate facing the display substrate and has a function of constraining the first particles. The display medium according to claim 19.

  The invention according to claim 21 is characterized in that the constraining layer is arranged at least in a surface direction on the surface of the display substrate facing the back substrate, and at least a first space in which a plurality of the first particles can exist. The pore diameter is changed by the application of the first stimulus and at least the first space communicates with the outside in the open state where the pore diameter is the largest, and at least in the open state, the first particles are externally connected to the first particle. 21. A hollow structure body including a connecting hole through which the first particles pass to enter the space of the first space, and transmits at least light in a visible light region. It is a display medium given in any 1 paragraph.

  According to a twenty-second aspect of the present invention, there is provided a display substrate that transmits at least light in the visible light region, a back substrate disposed to face the display substrate with a gap, and a space between the display substrate and the back substrate. A first particle that moves between the display substrate and the back substrate in response to the electric field formed between the substrate and the display substrate and the back substrate; A first space that is arranged at least in the surface direction on the surface of the display substrate facing the back substrate and in which at least a plurality of the first particles can exist, and the application of the first stimulus Because the hole diameter changes and the first space communicates with the outside at least in the opening state in which the hole diameter is the largest, and at least in the opening state, the first particles enter the first space from the outside. And a hollow structure that transmits at least light in the visible light region, and a voltage between the display substrate and the back substrate of the display medium. Voltage applying means for applying the first stimulus, first stimulus applying means for applying the first stimulus, and control means for controlling the voltage applying means and the first stimulus applying means in accordance with image information. Writing device.

  The invention according to claim 23 comprises an acquisition means for acquiring image information, and the control means controls the voltage application means and the first stimulus applying means in accordance with the image information acquired by the acquisition means. 23. The writing device according to claim 22, wherein:

  The invention according to claim 24 is characterized in that the control means applies the voltage for moving the first particles to the display substrate side or the back substrate side between the display substrate and the back substrate. 24. The first stimulus applying unit is controlled so as to apply a stimulus that causes the connecting hole to be in a closed state with the smallest hole diameter after controlling the applying unit. It is a writing device.

  The invention according to claim 25 is characterized in that the first stimulus applying means applies a stimulus of any one of an electric field, light, and heat as the first stimulus. The writing device according to any one of the above.

  According to a twenty-sixth aspect of the present invention, there is provided a display substrate that transmits at least light in the visible light region, a back substrate disposed to face the display substrate with a gap, and a space between the display substrate and the back substrate. A first particle that moves between the display substrate and the back substrate in response to the electric field formed between the substrate and the display substrate and the back substrate; A first space that is arranged at least in the surface direction on the surface of the display substrate facing the back substrate and in which at least a plurality of the first particles can exist, and the application of the first stimulus Because the hole diameter changes and the first space communicates with the outside at least in the opening state in which the hole diameter is the largest, and at least in the opening state, the first particles enter the first space from the outside. A display medium comprising: a connecting hole through which the first particle passes, and a hollow structure that transmits at least light in a visible light region; and the display substrate and the back substrate of the display medium. Voltage applying means for applying a voltage between the substrates, first stimulus applying means for applying the first stimulus, and control means for controlling the voltage applying means and the first stimulus applying means according to image information And a display device.

  The invention according to claim 27 comprises an acquisition means for acquiring image information, and the control means controls the voltage application means and the first stimulus applying means in accordance with the image information acquired by the acquisition means. 27. The display device according to claim 26.

  The invention according to claim 28 is characterized in that the control means applies the voltage for moving the first particles to the display substrate side or the back substrate side between the display substrate and the back substrate. 28. The first stimulus applying means is controlled so as to give a stimulus in which the connecting hole is in a closed state having the smallest hole diameter after controlling the applying means. It is a display device.

  The invention according to claim 29 is characterized in that the first stimulus applying means applies a stimulus of any one of an electric field, light and heat as the first stimulus. The display device according to any one of the above.

  According to the present invention, there is an effect of suppressing a decrease in display density.

  Hereinafter, the present invention will be described in detail.

(First embodiment)
As shown in FIG. 1, the display device 10 according to the embodiment of the present invention includes a display medium 12 and a writing device 13.

  The writing device 13 includes a voltage application unit 14, an image information acquisition unit 17, and a control unit 16. The voltage application unit 14 and the image information acquisition unit 17 are connected to the control unit 16 so as to be able to exchange signals.

  The display medium 12 corresponds to the display medium of the present invention, the display device 10 corresponds to the display device of the present invention, and the writing device 13 corresponds to the writing device of the present invention. The voltage application unit 14 corresponds to a voltage application unit and a first stimulus application unit of the display device and the writing device of the present invention.

-Display media-
The display medium 12 includes a display substrate 18 that serves as an image display surface, a rear substrate 20 that faces the display substrate 18 with a gap, and holds a predetermined distance between the substrates, and a gap between the display substrate 18 and the rear substrate 20. The gap member 34 partitioned into a plurality of cells, the dispersion medium 42, the hollow structure 26, the intermediate layer 38, and the first particles 36 enclosed in each cell are configured.
Although described in detail later, the first particles 36 move between the substrates by the action of an electric field formed between the display substrate 18 and the back substrate 20. The change in display color in the display medium 12 is caused by the movement of the first particles 36 between the substrates.

The cell indicates a region surrounded by the display substrate 18, the back substrate 20, and the gap member 34. The dispersion medium 42 is sealed in the cell. A plurality of first particles 36 (details will be described later) are dispersed in the dispersion medium 42. The plurality of first particles 36 move in the dispersion medium 42 between the display substrate 18 and the back substrate 20 according to the electric field strength formed in the cell. An intermediate layer 38 is provided in the cell (details will be described later).
In addition, in this cell, as will be described in detail later, the hollow structure 26 is laminated on the surface of the display substrate 18 facing the back substrate 20 (opposite surface side).

  In addition, the gap member 34 is provided so as to correspond to each pixel when an image is displayed on the display medium 12, and one or a plurality of cells are formed so as to correspond to each pixel. Each color display can be made possible. Note that, in this embodiment, for simplification of explanation and drawings, one cell is focused on. 9 and 10 which are other drawings used in the present embodiment, and FIGS. 12, 15, 18, 21, and 24 in the second to sixth embodiments described later. Similarly, for the sake of simplicity of explanation and drawing, one cell is shown.

  The display substrate 18 is configured by sequentially laminating a display electrode 24 and a surface layer 25 on a support substrate 22. The back substrate 20 is configured by sequentially laminating a back electrode 30 and a surface layer 32 on a support substrate 28.

  Examples of the support substrate 22 and the support substrate 28 include glass and plastics such as polycarbonate resin, acrylic resin, polyimide resin, polyester resin, epoxy resin, and polyether sulfone resin.

  For the back electrode 30 and the display electrode 24, oxides such as indium, tin, cadmium and antimon, composite oxides such as ITO, metals such as gold, silver, copper and nickel, organic materials such as polypyrrole and polythiophene are used. can do. These can be used as a single layer film, a mixed film, or a composite film, and can be formed by vapor deposition, sputtering, coating, or the like. Further, the thickness is usually 100 mm or more and 2000 mm according to the vapor deposition method or the sputtering method. The back electrode 30 and the display electrode 24 may be formed in a desired pattern, for example, a matrix shape or a stripe shape that enables passive matrix driving, by a conventionally known means such as etching of a conventional liquid crystal display device or a printed circuit board. it can.

  In addition, the display electrode 24 may be embedded in the support substrate 22. Similarly, the back electrode 30 may be embedded in the support substrate 28. In this case, since the materials of the support substrate 22 and the support substrate 28 may affect the charging characteristics and fluidity of the first particles 36, the material is selected according to the composition of each particle of the first particles 36.

  Note that the back electrode 30 and the display electrode 24 may be separated from the display substrate 18 and the back substrate 20 and disposed outside the display medium 12. In this case, the display medium 12 is sandwiched between the back electrode 30 and the display electrode 24, the distance between the back electrode 30 and the display electrode 24 is increased, and the electric field strength is reduced. It is necessary to devise measures such as reducing the thickness of the support substrate 22 and the support substrate 28 of the display medium 12 and the distance between the support substrate 22 and the support substrate 28, that is, the length of the gap member 34 so that It is.

  In the above description, the case where the electrodes (the display electrode 24 and the back electrode 30) are provided on both the display substrate 18 and the back substrate 20 has been described, but the display substrate 18 and the back substrate 20 may be provided on only one of them.

  In order to enable active matrix driving, the support substrate 22 and the support substrate 28 may include a TFT (thin film transistor) for each pixel. The TFTs are preferably formed not on the display substrate but on the back substrate 20 because wiring can be easily laminated and components can be easily mounted.

  In addition, when the display medium 12 is a simple matrix drive, the configuration of a display device 10 including the display medium 12 described later can be simplified, and the active matrix drive using TFTs is simpler than the simple matrix drive. Display speed can be increased.

  When the display electrode 24 and the back electrode 30 are formed on the support substrate 22 and the support substrate 28, respectively, a leak between the electrodes that causes damage to the display electrode 24 and the back electrode 30 or adhesion of the first particles 36. In order to prevent the occurrence of this, it is preferable to form the surface layer 25 and the surface layer 32 as dielectric films on the display electrode 24 and the back electrode 30 as necessary.

  As materials for forming the surface layer 25 and the surface layer 32, polycarbonate, polyester, polystyrene, polyimide, epoxy, polyisocyanate, polyamide, polyvinyl alcohol, polybutadiene, polymethyl methacrylate, copolymerized nylon, ultraviolet curable acrylic resin, fluororesin Etc. can be used.

In addition to the insulating material described above, an insulating material containing a charge transport substance in an insulating material (volume low efficiency of 10 ⁹ Ω · cm or more) is also used as a material constituting the surface layer 25 and the surface layer 32. it can. By incorporating the charge transport material into the material constituting the surface layer 25 and the surface layer 32, the chargeability of the particles by the charge injection to the first particles 36 is improved, and the charge amount of the first particles 36 is extremely large. In this case, the charge of the first particles 36 is leaked, and the charge amount of the first particles 36 is stabilized.

Examples of the charge transport material include a hydrazone compound, a stilbene compound, a pyrazoline compound, and an arylamine compound that are hole transport materials. Further, a fluorenone compound, a diphenoquinone derivative, a pyran compound, zinc oxide, or the like, which is an electron transport material, can also be used. Furthermore, a self-supporting resin having a charge transporting property can also be used.
Specific examples thereof include polyvinyl carbazole and polycarbonate obtained by polymerization of a specific dihydroxyarylamine and bischloroformate described in US Pat. No. 4,806,443. Since the dielectric film may affect the charging characteristics and fluidity of the particles, it is selected according to the composition of the particles. Since the display substrate which is one of the substrates needs to transmit light, it is preferable to use a transparent one of the above materials.

―Gap member―
The gap member 34 for holding the gap between the display substrate 18 and the back substrate 20 is formed so as not to impair the transparency of the display substrate 18, and is a thermoplastic resin, thermosetting resin, electron beam curable resin, photocuring. It can be formed of resin, rubber, metal or the like.

  The gap member 34 includes a cell type and a particle type. An example of the cellular type is a net. Since the net is easy to obtain and inexpensive, and the thickness is relatively uniform, it is useful when manufacturing an inexpensive display medium 12. The net is not suitable for displaying a fine image, and is preferably used for a large-sized image display device that does not require a high resolution. In addition, as other cellular spacers, a sheet in which holes are formed in a matrix by etching, laser processing, or the like can be cited. In this sheet, the thickness, the shape of the holes, the size of the holes, etc. are compared with the net. Easy to adjust. For this reason, the sheet is used as an image display medium for displaying a fine image, and the contrast is further improved.

The gap member 34 may be integrated with one of the display substrate 18 and the back substrate 20, and the support substrate 22 or the support substrate 28 is etched, laser processed, or a prefabricated mold is used and pressed. The support substrate 22 or the support substrate 28 having a cell pattern of any size and the gap member 34 can be produced by processing, printing, or the like.
In this case, the gap member 34 can be produced on either the display substrate 18 side, the back substrate 20 side, or both.

  The gap member 34 may be colored or colorless, but is preferably colorless and transparent so as not to adversely affect the display image displayed on the display medium 12, and in this case, for example, transparent such as polystyrene, polyester, or acrylic Resin or the like can be used.

  The particulate gap member 34 is preferably transparent, and glass particles can be used in addition to transparent resin particles such as polystyrene, polyester, and acrylic.

-Hollow structure 26-
Next, the hollow structure 26 will be described.
As shown in FIG. 2 (A), the hollow structure 26 has a first space 26A arranged at least in the surface direction on the surface facing the back substrate 20 of the display substrate 18, and a first stimulus. And a connecting hole 26B whose hole diameter changes.

Examples of the first stimulus for changing the hole diameter of the connection hole 26B of the hollow structure 26 include heat, light, electric field, and pH. In the first embodiment, as the first stimulus, A case where the action of an electric field is used will be described.
That is, in the first embodiment, the connection hole 26B of the hollow structure 26 changes to an open state or a closed state by the action of an electric field as a first stimulus.

  The connection hole 26B being in the “open state” means that the hole diameter of the connection hole 26B is the largest possible hole diameter of the connection hole 26B, and is in the “closed state”. Indicates that the hole diameter of the connecting hole 26B is the smallest possible hole diameter of the connecting hole 26B.

  The connecting hole 26B communicates the first space 26A with the outside at least in the opened state. Further, in this connection hole 26B, at least in this open state, the first particles 36 pass through to enter the first space 26A from the outside via the connection hole 26B.

  The hollow structure 26 transmits at least light in the visible light region. The first particles 36 are electrophoresed in the dispersion medium 42 through at least the open connection holes 26 </ b> B of the hollow structure 26 and the first space 26 </ b> A, and are disposed inside or outside the hollow structure 26.

  As shown in FIG. 2A, the plurality of first spaces 26 </ b> A included in the hollow structure 26 are arranged at least in the surface direction of the display substrate 18 on the side facing the back substrate 20 of the display substrate 18. Has been. The first space 26A is substantially spherical and has a size that allows a plurality of the first particles 36 to exist in the space.

  In the present embodiment, the case where the plurality of first spaces 26A in the hollow structure 26 have the same size will be described, but they may have different sizes.

  In the present embodiment, the first space 26A in the hollow structure 26 is described as being substantially spherical. However, the first space 36 may have a shape and size that allow a plurality of the first particles 36 to exist in the space. What is necessary is not limited to a spherical shape.

  In the connection hole 26B, as described above, the hole diameter is changed by the application of the first stimulus, and the first space 26A communicates with the outside in the opening state in which the hole diameter of the connection hole 26B is the largest. In the open state, the first particles 36 pass through from the outside to enter the first space 26A through the connection hole 26B. One or more connection holes 26B are provided in each first space 26A so as to satisfy such characteristics.

  In the present embodiment, “outside of the hollow structure 26” refers to the hollow structure 26 in the region (cell) filled with the dispersion medium 42 between the display substrate 18 and the back substrate 20. It is an area other than the occupied area.

  The hole diameter of the connection hole 26B is larger than the volume average primary particle diameter of the first particles 36 in a state where the hole diameter is expanded most by the application of the first stimulus (open state) (see FIG. 2A). In the state (closed state) in which the pore diameter is most narrowed by the application of 1 stimulus (see FIG. 2B), the volume average primary particle size of the first particles 36 is preferably smaller.

  When the connection hole 26B is opened or closed by the application of the first stimulus, for example, the first particles 36 that have reached the first space 26A via the connection hole 26B in the open state are When the first stimulus is applied to the connection hole 26B and is in a closed state when it exists in the first space 26A, the first particles 36 that have reached the first space 26A are It is stably held in the space 26A.

  If the hole diameter of the connecting hole 26B in the open state is smaller than the volume average particle diameter of the first particles 36, it becomes difficult to enter the first particles 36 into the first space 26A via the connecting hole 26B. .

  When the hole diameter of the connection hole 26B in the closed state is larger than the volume average particle diameter of the first particles 36, the first particles 36 that have reached the first space 26A via the connection hole 26B are transferred to the first particles 36A. Since the function held in the space 26A is reduced, the effect of suppressing the reduction in display density may be reduced.

  Furthermore, the hole diameter of the connection hole 26B is smaller than the diameter of the first space 26A in the opened state, and is preferably 0.8 times or less and 0.5 times or less of the diameter of the first space 26A. More preferably, it is more preferably 0.3 times or less.

  When the hole diameter of the connection hole 26B in this open state is 0.8 times or less the diameter of the first space 26A, the details will be described later, but a plurality of first particles 36 are connected to the first space via the connection hole 26B. The first space 26A is easily retained.

Moreover, the hole diameter of the connection hole 26 </ b> B in the open state needs to be large enough to allow the first particles 36 to pass through. When the hole diameter of the connection hole 26B in the opened state is a size that allows the first particles 36 to pass through easily, the first particles 36 can pass through the connection hole 26B.
Specifically, the hole diameter of the connecting hole 26B is larger than the volume average primary particle diameter of the first particles 36 in the opened state, and is 1.5 times or more than the volume average primary particle diameter of the first particles 36. It is preferable that it is 150 times or more.

  That is, the hole diameter of the connecting hole 26B is adjusted to be larger than the volume average primary particle diameter of the first particles 36 and smaller than the diameter of the first space 26A at least in the opened state.

Further, as described above, the hole diameter of the connecting hole 26B is a size that makes it difficult for the first particles 36 to easily pass through in the closed state. Since the hole diameter of the connecting hole 26B in the closed state is a size that makes it difficult for the first particles 36 to pass through easily, the first particles 36 that have reached the first space 26A are in the first state. It is stably held in the space 26A.
Specifically, the hole diameter of the connecting hole 26B in the closed state is smaller than the hole diameter in the open state, preferably 3/4 times or less, more preferably 2/3 times or less the hole diameter in the open state, It is especially preferable that it is 1/3 or less. In addition, the hole diameter of the connecting hole 26 </ b> B in the closed state is particularly preferably smaller than the volume average primary particle diameter of the first particles 36.

  Note that, as described above, the hole diameter of the connecting hole 26B is at least a size through which the first particles 36 can pass in the open state in which the hole diameter is expanded most by the application of the first stimulus, and the first stimulus. In the closed state where the pore diameter is the narrowest, it is sufficient that the probability of passage of at least the first particles 36 is sufficiently reduced. The hole diameter between the closed state and the open state is changed from the closed state to the open state. What is necessary is just to change so that a hole diameter may expand toward a closed state, and a hole diameter may narrow toward a closed state on the contrary, and a hole diameter should just change continuously or in steps.

  Here, the hole diameter of the connecting hole 26B indicates a minimum distance between regions facing the openings constituting the connecting hole 26B at the time of measurement. In the present embodiment, the diameter of each of the connecting holes 26B is set such that each of arbitrary 10 connecting holes 26B among the plurality of connecting holes 26B existing in the hollow structure 26 in the same state (opened state or closed state). , The minimum value of the distance between the facing regions of the openings constituting each connection hole 26B was measured, and the average value of the measurement results was taken as the hole diameter of the connection hole 26B.

  As described above, the hole diameter of the connection hole 26B in the opened state is the average diameter of the maximum hole diameter that each connection hole 26B can take, that is, the hole diameter in the state where the hole diameter is expanded most by the application of the first stimulus. is there. This open state means that the stimulus intensity changes when the first stimulus application conditions such as the intensity of the stimulus to be applied are changed in the direction in which the hole diameter of the connection hole 26B is increased. It shows the hole diameter in a state where the hole diameter does not expand any further.

  On the other hand, the hole diameter of the connection hole 26B in the closed state is, as described above, the hole diameter in the state where the hole diameter is the narrowest by the application of the first stimulus, that is, the average value of the minimum hole diameters that can be taken by each connection hole 26B. It is. This closed state means that when the first stimulus application condition such as the intensity of the stimulus to be applied is changed in the direction in which the hole diameter of the connection hole 26B is narrowed, the intensity of the stimulus is changed. It shows the hole diameter in a state where the hole diameter is not narrowed even further.

  Further, the diameter of the first space 26A indicates the minimum value of the distance between the regions facing the inner walls constituting the first space 26A. In the present embodiment, the diameter of the first space 26A is the same for each of the ten first spaces 26A among the plurality of first spaces 26A existing in the hollow structure 26. The minimum value of the distance between the opposing regions on the inner wall constituting the first space 26A was measured, and the average value of the measurement results was taken as the hole diameter of the first space 26A.

  The minimum value of the distance between the facing regions on the inner wall constituting the first space 26A and the hole diameter of the connecting hole 26B were measured using a scanning electron microscope (SEM, VE-9800, manufactured by Keyence Corporation).

  The porosity of the hollow structure 26 is preferably in the range of 40% to 95%, and preferably in the range of 50% to 90%.

  Furthermore, the thickness of the hollow structure 26 (the length in the direction in which the display substrate 18 and the back substrate 20 face each other) depends on the cell depth, the concentration and the particle size of the first particles 36, and is within the range. More specifically, it is preferably in the range of 0.5 μm or more and 100 μm or less.

  Further, the hollow structure 26 transmits light in the visible light region. “Transmit light in the visible light region” in the present embodiment indicates that the light transmittance in the visible light region is 60% or more.

  The difference in refractive index between the hollow structure 26 and the dispersion medium 42 is preferably about 0.01 or more and 1 or less, for example. A small difference in refractive index is preferable from the viewpoint of optical characteristics because the transparency of the hollow structure 26 is increased.

  The first particles 36 encapsulated between the display substrate 18 and the back substrate 20 move between the substrates when an electric field for electrophoresis of the first particles 36 is formed between the substrates. The structure 26 reaches the first space 26 </ b> A via the open connection hole 26 </ b> B.

  In the present embodiment, a case where the first space 26A is further provided in a single layer in the direction in which the display substrate 18 and the back substrate 20 face each other will be described. As shown in FIG. It is preferable that a plurality of structures arranged in the surface direction of the display substrate 18 are formed as one layer, and a plurality of layers are further stacked in the facing direction of the display substrate 18 and the back substrate 20.

  The first space 26 </ b> A in the hollow structure 26 has a configuration in which a plurality of first spaces 26 </ b> A are arranged in the surface direction of the display substrate 18, and a plurality of first spaces 26 </ b> A are stacked in the facing direction of the display substrate 18 and the back substrate 20. In this case, the first particles 36 that have electrophoresed from the back substrate 20 side to the display substrate 18 side pass through one or a plurality of open connection holes 26B and a plurality of first spaces 26A of the hollow structure 26. Thus, it reaches any one of the plurality of first spaces 26 </ b> A in the hollow structure 26.

  When a plurality of first spaces 26A are stacked in the direction in which the display substrate 18 and the back substrate 20 face each other, for example, the first particles 36 that have reached the display substrate 18 side are formed into a plurality of layers of the first spaces 26A. It exists in the 1st space 26A of each layer of the hollow structure 26 which consists of. For this reason, compared with the case where the first particles 36 exist in each first space 26A of the hollow structure 26 constituted by the first layer 26A of one layer, the first space 26A of a plurality of layers is used. When the first particles 36 exist in each first space 26A in each layer of the structured hollow structure 26, a larger number of first particles 36 are formed depending on the facing direction of the display substrate 18 and the back substrate 20. When the display medium 12 is viewed from the display substrate 18 side, the color due to the first particles 36 can be presented more intensely. In addition, a decrease in concentration can be suppressed as compared with a single layer.

As described above, when the connection hole 26B is in the open state, the first particle that has entered the hollow structure 26 through the connection hole 26B having a larger diameter than the volume average primary particle diameter of the first particles 36. The particles 36 move between the first spaces 26A through the connection holes 26B. Here, since the hole diameter of the connection hole 26B is smaller than the diameter of the first space 26A even in the opened state, when the plurality of first particles 36 enter the same first space 26A, The first particles 36 are held in the first space 26 </ b> A, and as a result, are held in the hollow structure 26.
Further, since the connection hole 26B changes from the open state to the closed state or from the closed state to the open state by the application of the first stimulus, the first particle 36 enters the first space 26A. By applying the first stimulus for changing the connection hole 26B from the open state to the closed state, the first particles 36 can be held in the first space 26A.
For this reason, it can be said that the hollow structure 26 has a function of restraining the first particles 36 inside.

  The hollow structure 26 may be an inverted opal structure in which the first spaces 26A having the same size (diameter) are regularly arranged in the surface direction of the display substrate 18 and the facing direction between the substrates, The first space 26A having different sizes (diameters) may be irregularly arranged.

As a method for manufacturing the hollow structure 26 of the present embodiment, a solution of a stimulus response material (detailed later) is filled in a gap between colloidal particle structures to be described later, and the solvent of the solution is evaporated to cause capillary action. After the solution is localized in the contact area between the particles constituting the colloidal particle structure, the tubular body 27A constituting the connection hole 26B (FIG. 4 (FIG. C)) is adjusted.
Thereafter, a template is formed by, for example, plating, filling with a silica material, filling with a polymer material, impregnation and polymerization with a polymerizable monomer, electrolytic polymerization, etc. in the gap between the colloidal particle structures in which the tubular body 27A is formed in the contact region By filling the substance and then removing the structure, the hollow structure 26 in which the first space 26A and the connection hole 26B are formed is adjusted.

  In addition, after covering and filling the precursor of the template material, a treatment such as baking may be performed to obtain the template material. Further, an optical modeling technique such as a femtosecond laser may be used.

  The colloidal particle structure is a non-close-packed structure that is packed using repulsive forces between colloidal particles, or a close-packed structure that is closely packed with colloidal particles. Examples of colloidal particles include particles having a volume average primary particle size of 10 nm to 1,000 nm, silica particles, polymer particles (polystyrene, polyester, polyimide, polyolefin, methyl poly (meth) acrylate, polyethylene, polypropylene, polyethylene, polyethersulfone). , Nylon, polyurethane, polyvinyl chloride, polyvinylidene chloride, etc.) and other inorganic particles such as titanium oxide).

  Such colloidal particles include, for example, emulsion polymerization, suspension polymerization, two-stage template polymerization, chemical gas phase reaction method, electric furnace heating method, thermal plasma method, laser heating method, gas evaporation method, coprecipitation method, It can be prepared by a uniform precipitation method, a compound precipitation method, a metal alkoxide method, a hydrothermal synthesis method, a sol-gel method, a spray method, a freezing freezing method, and a nitrate decomposition method. The colloidal particle structure is a method in which colloidal particles are deposited on a substrate using a colloidal particle dispersion by self-organization by gravity sedimentation or coating / drying, or by the action of an electric or magnetic field. Further, the substrate can be produced by a method of immersing and pulling up the substrate in a colloidal particle dispersion and forming it on the substrate.

  The colloidal particle structure has a thickness of 1 μm to 5 mm, preferably 1 μm to 1 mm.

  As the stimulus response material used for adjusting the tubular body 27A constituting the connection hole 26B, in the present embodiment, the action of an electric field is used as the first stimulus for changing the hole diameter of the connection hole 26B. What is necessary is just to use the material from which the hole diameter of the connection hole 26B changes because an electric field acts on the tubular body 27A which comprises the hole 26B.

  Here, the change of the hole diameter of the connection hole 26B due to the action of the electric field causes the volume to shrink isotropically or anisotropically by the electric field acting on the material constituting the tubular body 27A constituting the connection hole 26B. As a result, the hole diameter of the connecting hole 26B is reduced.

  In order to cause the volume change of the tubular body 27A to change the connection hole 26B to the open state or the closed state, the voltage value and the voltage application time of the voltage applied between the display substrate 18 and the back substrate 20 are described. May vary depending on the material constituting the tubular body 27A, the dispersion medium, the additive, and the like, but may be measured in advance when the display medium 12 is configured.

  Specifically, as the stimulus-responsive material that changes by the action of the electric field, an electrolyte polymer material is preferable, and a cross-linked product of poly (meth) acrylic acid or a salt thereof, (meth) acrylic acid and (meth) Cross-linked products and salts of copolymers with acrylamide, hydroxyethyl (meth) acrylate, alkyl (meth) acrylate, cross-linked polymaleic acid and salts, maleic acid and (meth) acrylamide, hydroxyethyl (meta ) Copolymers and salts of copolymers with acrylates, (meth) acrylic acid alkyl esters, etc., crosslinked products of polyvinyl sulfonic acid, vinyl sulfonic acid and (meth) acrylamide, hydroxyethyl (meth) acrylate, (meth) acrylic Cross-linked products of copolymers with acid alkyl esters, cross-linked polyvinyl benzene sulfonic acid And salts thereof, crosslinked products of copolymers of vinylbenzene sulfonic acid and (meth) acrylamide, hydroxyethyl (meth) acrylate, alkyl (meth) acrylate, etc., and salts thereof, crosslinked products of polyacrylamide alkyl sulfonic acid, Cross-linked products and salts of such salts, acrylamide alkyl sulfonic acids and copolymers of (meth) acrylamide, hydroxyethyl (meth) acrylate, alkyl (meth) acrylate, and polydimethylaminopropyl (meth) acrylamide And its hydrochloride, dimethylaminopropyl (meth) acrylamide and (meth) acrylic acid, (meth) acrylamide, hydroxyethyl (meth) acrylate, (meth) acrylic acid alkyl ester cross-linked products and their Quaternized compounds, salts, poly A cross-linked product of a complex of methylaminopropyl (meth) acrylamide and polyvinyl alcohol, a quaternized product or a salt thereof, a cross-linked product of a composite of polyvinyl alcohol and poly (meth) acrylic acid or a salt thereof, a carboxyalkyl cellulose salt Examples thereof include a cross-linked product, a partial hydrolyzate of a cross-linked product of poly (meth) acrylonitrile, and a salt thereof.

In addition, as a material that stimulates and responds by an electrochemical reaction accompanying application of an electric field, a metal complex such as a ferrocene derivative, cobaltcenium, ruthenium, a transition metal, a fullerene derivative, a porphyrin, an expanded porphyrin, a pyrrole compound, a phenothiazine, a viologen derivative, Examples include phenothiazine derivatives, thiophene compounds, aniline compounds, carbazole derivatives, tetrathiafulvalene derivatives, diamine compounds, phthalocyanine compounds, hydrazone compounds, oxadiazole derivatives, perylene derivatives, naphthalene derivatives, and other porphyrins and oxides. Examples thereof include gel structures having ecologically derived substances such as reduced proteins as functional groups, and polymers such as polypyrrole and polyaniline that are oxidized and reduced by a polymer matrix.
In addition, stimuli-responsive materials that change in volume by the movement of ions in the gel by applying an electric field include polyether derivatives, polypyrrole derivatives, fluorine-based ion exchange resin derivatives, polyester derivatives, polyimine derivatives, and polymers impregnated with ionic liquids. Examples thereof include gels and polymers containing them.
Etc.

  Among these, a crosslinked product of poly (meth) acrylic acid or a derivative of its salt is preferably used for reasons of cost and handling.

  As the solvent for the stimulus responsive material, any known solvent may be used as long as it has an insulating function. Specifically, hexane, cyclohexane, toluene, xylene, decane, hexadecane, kerosene, paraffin, isoparaffin are used. , Silicone oil, dichloroethylene, trichlorethylene, perchlorethylene, high purity petroleum, ethylene glycol, alcohols, ethers, esters, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, N-methylpyrrolidone, 2-pyrrolidone, N- Methylformamide, acetonitrile, tetrahydrofuran, propylene carbonate, ethylene carbonate, benzene, diisopropylnaphthalene, olive oil, isopropanol, trichlorotrifluoroethane, te La chloroethane, and the like dibromotetrafluoroethane, mixtures thereof can be preferably used.

  In addition, as a template material used to form the first space 26A, inorganic materials such as silica and calcium carbonate, sol-gel glass, thermosetting resin, ultraviolet curable resin, electron beam curable resin, polyester, polyimide, polymethacrylic acid Acrylic resins such as methyl, polystyrene and derivatives thereof, polyethylene, polypropylene, polyamide, polyvinyl chloride, polyvinylidene chloride, polycarbonate, polyether sulfone, cellulose derivatives, fluorine resins, silicone resins, epoxy resins, polyacetal resins, etc. Is mentioned.

  As a method for producing the hollow structure 26, specifically, for example, as shown in FIG. 4A, a colloidal particle structure 29 made of, for example, silica particles is produced, and then the stimulus response material is dissolved in a solvent. The monomer solution 37 is filled in the gaps of the colloidal particle structure 29 (see FIG. 4B)). Then, the solvent of the monomer solution 37 filled in the colloidal particle structure 29 is evaporated by applying heat.

  At this time, when the volume of the monomer solution 37 is reduced by evaporation of the solvent of the monomer solution 37, the monomer solution 37 is localized to the contact region between the particles constituting the colloidal particle structure 29 by capillary action ( FIG. 6 (A) and FIG. 6 (B) refer to the monomer solution 37A in a localized state). Then, the monomer solution 37A in a state of being localized in the contact region between the particles constituting the colloid particle structure 29 is subjected to treatment such as thermal initiation reaction, redox initiation reaction, UV curing reaction, ion polymerization and the like. By curing or resinating (polymerization), a tubular body 27A as a monomer solution 37A cured or resinated is formed in the contact area between the particles constituting the colloidal particle structure 29 (FIG. 4). (See (C)).

Then, the surface and gaps of the colloidal particle structure 29 on which the tubular body 27A is formed are coated with a conductive material precursor such as furfuryl alcohol resin, fired, and fired as the conductive material 33. Carbonized carbon is filled in the surface and gaps of the colloidal particle structure 29 (FIG. 5D).
When the colloidal particle structure 29 is removed by etching with hydrofluoric acid or the like, the first space 26A having the same shape as the colloidal particle structure 29 and a tubular body whose pore diameter is changed by the action of an electric field as a first stimulus. A negative-type hollow structure 26 having a connection hole 26B formed by 27A is produced (see FIG. 5E).

  The method for producing the hollow structure 26 is not limited to the above method, and any method can be used as long as the hollow structure 26 can be manufactured using the hollow structure having the connection hole 26B and the first space 26A. It may be used.

-First particle 36-
A plurality of first particles 36 are enclosed in the dispersion medium 42 of the display medium 12 of the present invention. The first particles 36 have a voltage exceeding the voltage range for migration (hereinafter referred to as the migration voltage range) predetermined between the display substrate 18 and the back substrate 20 according to the first particles 36. When applied, an electric field of a predetermined electric field strength or more is formed between the display substrate 18 and the back substrate 20, thereby moving in the dispersion medium 42.

  The change in display color in the display medium 12 is caused by the movement of the plurality of first particles 36 in the dispersion medium 42 in the dispersion medium 42.

First, the movement of the first particles 36 by the electric field in the dispersion medium 42 will be described.
As described above, an electrophoretic voltage range necessary for the first particles 36 to move between the display substrate 18 and the back substrate 20 (in the dispersion medium 42) is defined. That is, the first particle 36 has a voltage required for the particle to start moving and a change in display density even when the voltage and voltage application time are further increased from the start of movement until the display density is saturated. It has a migration voltage range as a range up to the voltage.
The voltage indicates a voltage applied between the display substrate 18 and the back substrate 20.

  Note that a voltage having a voltage value within this migration voltage range will be referred to as a voltage necessary for the first particles 36 to move in accordance with the electric field.

  The display density when the “display density is saturated” is obtained by measuring the color density on the display substrate 18 side of the display medium 12 with an optical density (Optical Density = OD) reflection densitometer of X-rite. Then, a voltage is applied between the display substrate 18 and the back substrate 20 side, and this voltage is gradually changed in the direction of increasing the measured concentration (applied voltage value is increased or decreased) to change the concentration per unit voltage. Is saturated, and even when the voltage and the voltage application time are increased in this state, the concentration does not change, and the concentration is shown when the concentration is saturated.

  That is, when a voltage outside the above voltage range is applied between the display substrate 18 and the back substrate 20, the display density of the display medium 12 does not change, and the voltage within the migration voltage range does not change. And the back substrate 20, a change appears in the display density of the display medium 12 due to the movement of the first particles 36.

  In this “change in the display density of the display medium 12” state, a voltage is applied to the display electrode 24 and the back electrode 30 of the display medium 12, and this voltage value is continuously changed from 0 V to display The change in density is evaluated by visual observation, and represents a state in which the change appears. In this evaluation, the state in which the change in the display density appears is that the density of the display substrate 18 is measured by a densitometer (X-Rite 404A, manufactured by X-Rite). This represents a state where the amount of change was 0.1 or more.

  In order to adjust the migration voltage range of the first particles 36, the average charge amount of the particles constituting the first particles 36, the flow resistance to the dispersion medium on the surface of each particle, the average magnetic amount (magnetization strength) Any one or more of the volume average primary particle size of the particles and the shape factor of the particles may be adjusted.

  The first particles 36 do not have the voltage range necessary for moving the particles as described above, and may be configured to move regardless of the voltage applied. However, as described above, the voltage range is a desirable mode because the display image has a memory property and the image can be stored without consuming power.

  In the present embodiment, the case where only the first particles 36, that is, particles of one color, are enclosed in the display medium 12 will be described. A plurality of types of particles having different voltage ranges may be enclosed. In this case, the first particles 36 may be adjusted in advance so that the electrophoretic voltage ranges described above are different for each type (each color) of the plurality of types of first particles 36. In this way, by applying a voltage within a specific electrophoretic voltage range between the substrates, the first particles 36 of the color to be moved can be selectively moved between the substrates. Multicolor display by movement of the particles 36 between the substrates becomes possible.

  The first particles 36 are sized to pass through at least the open connection holes 26B of the hollow structure 26 and the holes (details will be described later) of the intermediate layer 38, that is, smaller than these hole diameters. The volume average primary particle size of the first particles 36 is preferably in the range of 10 nm to 5000 nm, more preferably in the range of 50 nm to 2000 nm, and still more preferably in the range of 70 nm to 1000 nm. .

  Here, as a method for measuring the volume average primary particle diameter, laser diffraction is performed by irradiating a plurality of first particles 36 with laser light and measuring the average particle diameter from the diffraction emitted from the first particle 36 and the intensity distribution pattern of scattered light. The scattering method is adopted. In addition, the measurement was performed at 25 ° C. using a dynamic light scattering type particle size distribution measuring device (LB-550, Horiba, Ltd.).

  The concentration (weight ratio) of the first particles 36 varies depending on the pigment concentration in the first particles 36, but is preferably not in the range of 1% by volume or more and 70% by volume or less with respect to the dispersion medium 42. More preferably, it is in the range of 2 volume% or more and 50 volume% or less, and more preferably 3 volume% or more and 30 volume% or less. If the density of the first particles 36 is too low, there may be a problem that a sufficient color density cannot be obtained. If the density is too high, agglomeration occurs or the display speed decreases due to an increase in viscosity. There is a case.

  The content (% by weight) of the first particles 36 with respect to the total mass in the cell is not particularly limited as long as the desired hue is obtained, and the cell thickness (that is, the display substrate 18 and The content is adjusted according to the distance between the back substrate 20 and the substrate. That is, in order to obtain a desired hue, the content decreases as the cell becomes thicker, and the content increases as the cell becomes thinner. Generally, it is 0.01 wt% or more and 50 wt% or less.

  Note that the size of the cell in the display medium 12 is not particularly limited, but in order to prevent display density unevenness due to a deviation in the display surface of the first particles 36, the display substrate 18 of the display medium 12 is usually used. The length in the plate surface direction is about 10 μm or more and 1 mm or less.

  Examples of the first particles 36 having the property of electrophoresis in the dispersion medium 42 by the electric field include glass beads, insulating metal oxide particles such as alumina and titanium oxide, thermoplastic or thermosetting resin particles, and the like. Examples include those having a colorant fixed on the surface of the resin particles, particles containing an insulating colorant in a thermoplastic or thermosetting resin, and the like by applying a specific surface treatment to these particles. The first particles 36 are brought into a dispersed state or agglomerated state by electric field stimulation as described above.

  Examples of the thermoplastic resin used for producing the first particles 36 include styrenes such as styrene and chlorostyrene, monoolefins such as ethylene, propylene, butylene, and isoprene, vinyl acetate, vinyl propionate, vinyl benzoate, and butyric acid. Α-methylene such as vinyl ester such as vinyl, methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, dodecyl methacrylate Aliphatic monocarboxylic acid esters, vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl butyl ether, homopolymers of vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, vinyl isopropenyl ketone, or It can be exemplified polymer.

  Examples of the thermosetting resin used for the production of the first particles 36 include cross-linked resins mainly composed of divinylbenzene and cross-linked resins such as cross-linked polymethyl methacrylate, phenol resins, urea resins, melamine resins, and polyester resins. And silicone resins. Particularly representative binder resins include polystyrene, styrene-alkyl acrylate copolymer, styrene-alkyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer. Examples thereof include a polymer, polyethylene, polypropylene, polyester, polyurethane, epoxy resin, silicone resin, polyamide, modified rosin, and paraffin wax.

As the colorant, organic or inorganic pigments, oil-soluble dyes, etc. can be used, magnetic powders such as magnetite and ferrite, carbon black, titanium oxide, magnesium oxide, zinc oxide, phthalocyanine copper-based cyan colorant, Known colorants such as an azo yellow color material, an azo magenta color material, a quinacridone magenta color material, a red color material, a green color material, and a blue color material can be given. Specifically, aniline blue, calcoil blue, chrome yellow, ultramarine blue, duPont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxalate, lamp black, rose bengal, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 57: 1, C.I. I. Pigment yellow 97, C.I. Blue 15: 1, C.I. I. Pigment Blue 15: 3, etc. can be exemplified as typical ones.
Also, porous sponge-like particles or hollow particles enclosing air can be used as white particles.

  A charge control agent may be mixed in the resin of the first particles 36 as necessary. As the charge control agent, known materials used for toner materials for electrophotography can be used. For example, cetylpyridyl chloride, BONTRON P-51, BONTRON P-53, BONTRON E-84, BONTRON E-81 (above, Quaternary ammonium salts such as Orient Chemical Industry Co., Ltd., salicylic acid metal complexes, phenol condensates, tetraphenyl compounds, metal oxide particles, and metal oxide particles surface-treated with various coupling agents. .

A magnetic material may be mixed in the inside and the surface of the first particles 36 as necessary. As the magnetic material, a color-coated inorganic magnetic material or organic magnetic material is used as necessary. Further, a transparent magnetic material, in particular, a transparent organic magnetic material does not hinder the color development of the color pigment, and the specific gravity is smaller than that of the inorganic magnetic material, and is more desirable.
As the colored magnetic powder, for example, a small-diameter colored magnetic powder described in JP-A-2003-131420 can be used. A material provided with magnetic particles serving as nuclei and a colored layer laminated on the surface of the magnetic particles is used. The colored layer may be selected such that the magnetic powder is opaquely colored with a pigment or the like, but it is preferable to use, for example, a light interference thin film. This optical interference thin film is a thin film having a thickness equivalent to the wavelength of light made of an achromatic material such as SiO ₂ or TiO ₂ , and reflects light in a wavelength selective manner by optical interference in the thin film. is there.

  An external additive may be attached to the surface of the first particle 36 as necessary. The color of the external additive is preferably transparent so as not to affect the color of the particles.

  As the external additive, inorganic particles such as silicon oxide (silica), titanium oxide, and metal oxides such as alumina are used. In order to adjust the charging property, fluidity, and environment dependency of the particles, they can be surface-treated with a coupling agent or silicone oil.

  Coupling agents include positively chargeable ones such as aminosilane coupling agents, aminotitanium coupling agents, nitrile coupling agents, and silanes that do not contain nitrogen atoms (consisting of atoms other than nitrogen). There are negatively charged ones such as coupling agents, titanium-based coupling agents, epoxy silane coupling agents, and acrylic silane coupling agents. Similarly, silicone oil includes positively charged ones such as amino-modified silicone oil, dimethyl silicone oil, alkyl-modified silicone oil, α-methylsulfone-modified silicone oil, methylphenyl silicone oil, chlorophenyl silicone oil, fluorine Examples include negatively chargeable ones such as modified silicone oils. These are selected according to the desired resistance of the external additive.

Of these external additives, well-known hydrophobic silica and hydrophobic titanium oxide are preferable, and in particular, the reaction of TiO (OH) ₂ described in JP-A-10-3177 with a silane compound such as a silane coupling agent. The titanium compound obtained in (1) is preferred. As the silane compound, any of chlorosilane, alkoxysilane, silazane, and a special silylating agent can be used. This titanium compound is produced by reacting TiO (OH) ₂ produced in a wet process with a silane compound or silicone oil and drying it. Since it does not pass through the firing step of several hundred degrees, a strong bond between Ti is not formed, there is no aggregation, and the particles are in the state of primary particles. Furthermore, since the silane compound or silicone oil reacts directly with TiO (OH) ₂ , the amount of silane compound or silicone oil treated can be increased, and the charging characteristics can be controlled by adjusting the amount of silane compound treated. The charging ability that can be imparted and can be imparted can be significantly improved over that of conventional titanium oxide.

  The primary particles of the external additive are generally 1 nm to 1000 nm, preferably 2 nm to 100 nm, but are not limited thereto.

  The mixing ratio of the external additive and the particles is adjusted based on the balance between the particle size of the particles and the particle size of the external additive. If the amount of the external additive added is too large, a part of the external additive is liberated from the particle surface and adheres to the surface of the other particle, so that desired charging characteristics cannot be obtained. In general, the amount of the external additive is 0.1 to 70 parts by weight, more preferably 1 to 50 parts by weight with respect to 100 parts by weight of the particles.

  The external additive may be added only to any one of a plurality of types of particles, or may be added to a plurality of types or all types of particles. When an external additive is added to the surface of all particles, the external additive may be applied to the particle surface with impact force, or the particle surface may be heated to firmly fix the external additive to the particle surface. desirable. As a result, the external additive is released from the particles, and the external additive of different polarity is strongly aggregated to prevent the formation of an aggregate of the external additive that is difficult to dissociate with an electric field. Is prevented.

  The first particles 36 are hollow due to the repulsive force between the inner wall of the hollow structure 26 and the particle surface, as well as the property of moving between the substrates by the electric field formed between the display substrate 18 and the back substrate 20. What further has the characteristic hold | maintained in the state aggregated inside the 1st space 26A of the structure 26 may be used.

  As described above, the first particles 36 are moved between the substrates by the electric field formed between the display substrate 18 and the back substrate 20, and the repulsive force between the inner wall of the hollow structure 26 and the particle surface. In the case of using the hollow structure 26 that further has the property of being held in an aggregated state in the first space 26 </ b> A, the first particles 36 are formed between the display substrate 18 and the back substrate 20. When a predetermined voltage within the migration voltage range or exceeding the migration voltage range is applied between the substrates, the substrate moves in the dispersion medium 42 and reaches the first space 26A of the hollow structure 26. The first space 26A is held in an aggregated state

  As the first particles 36 having the characteristics of electrophoresis in the dispersion medium 42 by this electric field and the aggregation characteristics due to the repulsive force with the inner wall constituting the first space 26A of the hollow structure 26, pigment particles and pigments are encapsulated. Particles having a pigment surface modified with a functional group, particles containing a pigment in a resin, dye particles, particles encapsulating a dye, particles containing a dye in a resin, and the like. By applying a specific surface treatment to either one or both of the particles and the inner wall constituting the first space 26A of the hollow structure 26, the aggregation characteristics due to repulsion with the inner wall of the hollow structure 26 as described above can be obtained. The first particles 36 are provided.

  As this specific surface treatment, in order to configure the first particles 36 so as to generate repulsive force between the inner walls of the first spaces 26 </ b> A of the hollow structures 26, For example, the surface of the inner wall of the structure 26 may be configured to carry the same charge and cause electrostatic repulsion.

  Specifically, for example, a hollow structure is made of a polymer material and subjected to corona discharge treatment to electret to charge a positive charge, while the surface of the first particle 36 is modified with an amino group. Is configured to generate a repulsive force between the first particle 36 and the inner wall of the first space 26A.

Further, the inner wall of the hollow structure 26 (the wall constituting the first space 26A and the connecting hole 26B) may be subjected to a surface treatment so that repulsive force is generated between the first particles 36. Good.
In this case, for example, an amino group is modified on the inner wall of the hollow structure 26 by a coupling agent to charge a positive charge, and similarly, the amino group is modified on the surface of the first particle 36 to charge it to a positive charge. Just do it. In either case, repulsive force is generated if the positive charges are negative charges.

  Specifically, the inner wall of the hollow structure 26 may be subjected to a surface treatment with a material having the same charge according to the material constituting the surface of the first particle 36.

  As a method for producing the first particles 36, the same method as the particles that move between the substrates according to the electric field described above can be used.

-Dispersion medium-
The dispersion medium 42 is determined according to the surface characteristics of the first particles 36. The dispersion medium 42 and the first particles 36 have high affinity in the dispersed state, and the dispersion medium 42 and the first particles 36 in the aggregated state. A liquid having a property of lowering the affinity with the liquid is used, and an insulating liquid is preferable because it provides a sufficient potential gradient in the bulk.

  Specific examples of the insulating liquid include hexane, cyclohexane, toluene, xylene, decane, hexadecane, kerosene, paraffin, isoparaffin, silicone oil, dichloroethylene, trichloroethylene, perchloroethylene, high-purity petroleum, ethylene glycol, and alcohols. , Ethers, esters, dimethylformamide, dimethylacetamide, dimethylsulfoxide, N-methylpyrrolidone, 2-pyrrolidone, N-methylformamide, acetonitrile, tetrahydrofuran, propylene carbonate, ethylene carbonate, benzine, diisopropylnaphthalene, olive oil, isopropanol, trichloro Trifluoroethane, tetrachloroethane, dibromotetrafluoroethane, etc. and mixtures thereof are preferred. It can be used for.

Moreover, water (so-called pure water) can also be suitably used as a dispersion medium by removing impurities so as to have the following volume resistance value. The volume resistance value is preferably 10 ³ Ωcm or more, more preferably 10 ⁷ Ωcm to 10 ¹⁹ Ωcm, and further preferably 10 ¹⁰ cm to 10 ¹⁹ Ωcm. By setting such a volume resistance value, the generation of bubbles due to the electrolysis of the liquid due to the electrode reaction is more effectively suppressed, and the electrophoretic characteristics of the particles are not impaired every time energization is achieved. Repeatable stability can be imparted.

  The insulating liquid can be added with an acid, alkali, salt, dispersion stabilizer, stabilizer for the purpose of anti-oxidation or UV absorption, antibacterial agent, preservative, etc., if necessary. It is preferable to add so that it may become the range of the specific volume resistance value shown above.

For insulating liquids, anionic surfactants, cationic surfactants, amphoteric surfactants, nonionic surfactants, fluorosurfactants, silicone surfactants, metal soaps as charge control agents , Alkyl phosphate esters, succinimides and the like can be added.
It has ionic and nonionic surfactants, block or graft copolymers consisting of lipophilic and hydrophilic parts, and also has a polymer chain skeleton such as cyclic, star-like, and dendritic polymers (dendrimers). Further, a compound selected from a metal complex of salicylic acid, a metal complex of catechol, a metal-containing bisazo dye, a tetraphenylborate derivative and the like can be used.
Can be given.

  More specific examples of the ionic and nonionic surfactants are as follows. Nonionic activators include polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene dodecyl phenyl ether, polyoxyethylene alkyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, And fatty acid alkylolamide. Examples of the anionic surfactant include alkylbenzene sulfonate, alkylphenyl sulfonate, alkyl naphthalene sulfonate, higher fatty acid salt, sulfate of higher fatty acid ester, sulfonic acid of higher fatty acid ester, and the like. Examples of the cationic surfactant include primary to tertiary amine salts and quaternary ammonium salts. These charge control agents are preferably 0.01% by weight or more and 20% by weight or less, and particularly preferably 0.05% by weight or more and 10% by weight or less, based on the solid content of the particles. If the amount is less than 0.01% by weight, the desired charge control effect is insufficient, and if it exceeds 20% by weight, the conductivity of the developer increases excessively, making it difficult to use.

  In addition, the viscosity of the dispersion medium 42 is in the range of 0.1 mPa · s to 20 mPa · s in an environment of a temperature of 20 ° C., which is essential from the viewpoint of the moving speed of the particles, and thus the display speed. It is preferably from s to 5 mPa · s, more preferably from 0.1 mPa · s to 2 mPa · s.

  When particles that aggregate due to repulsion with the inner wall of the hollow structure 26 are used as the first particles 36, the dispersion medium 42 inhibits repulsion of both the first particles 36 and the hollow structure 26. However, it is preferable to use a dispersion medium 42 having non-electrolyte characteristics among these dispersion mediums 42. As in the first embodiment, an insulating liquid is preferable.

―Middle layer―
As described above, the intermediate layer 38 is provided between the display substrate 18 of the display medium 12 and the rear substrate 20 on the rear substrate 20 side of the hollow structure 26 laminated on the rear substrate 20 side of the display substrate 18. It has been.

  The intermediate layer 38 in the display medium 12 of the present embodiment has a hole through which the first particles 36 move and has optical reflection characteristics different from those of the first particles 36.

  The holes provided in the intermediate layer 38 are at least holes extending in the direction of the electric field gradient formed in the display medium 12, and in the present embodiment, the display electrode 18 and the back electrode 30 form the display substrate 18. The holes are at least formed in the electric field gradient direction formed between the rear substrate 20, that is, in the direction in which the display substrate 18 and the rear substrate 20 face each other. The holes of the intermediate layer 38 are sized so that at least the particles constituting the first particles 36 can move from one of the display substrate 18 and the back substrate 20 to the other substrate side through the holes. It is configured.

  The intermediate layer 38 “has an optical reflection characteristic different from that of the first particles 36” means that the dispersion medium 42 in which only the first particles 36 are dispersed and the dispersion medium 42 penetrated into the holes. This means that when the hollow structure 26 is compared with the visual observation, there is a difference in which the difference between the two can be identified in hue, brightness, freshness, and the like.

  The intermediate layer 38 preferably has a function of shielding the first particles 36. Here, “concealment” in the present embodiment means a case where the transmittance is 50% or less with respect to visible light.

  Therefore, when the first particles 36 are closer to the display substrate 18 than the intermediate layer 38, the color of the first particles 36 is different from when the first particles 36 are closer to the rear substrate 20 than the intermediate layer 38. The color of the intermediate layer 38 is displayed on the display medium 12.

The color of the intermediate layer 38 is preferably white because the display can be performed with a bright white background, and the whiteness is preferably 30% or more, particularly 40% or more. preferable.
The whiteness is a measure of whiteness, and is specifically a value measured using a Hunter whiteness meter or X-rite colorimeter according to the method described in JIS-P8123.

  The thickness of the intermediate layer 38 is desirably at least equal to or larger than the volume average primary particle size of the particles constituting the first particles 36. Since the first particles 36 present on the back substrate 20 side of the intermediate layer 38 may be observed from the hole portion of the intermediate layer 38, the thickness of the intermediate layer 38 is the volume average primary particle of the first particles 36. It is further desirable that the diameter is 3 times or more of the diameter.

Specifically, the thickness of the intermediate layer 38 depends on the distance between the display substrate 18 and the back substrate 20, but is preferably 0.1 μm or more and 5000 μm or less, and preferably 1 μm or more and 500 μm or less. More preferably.
If the thickness of the intermediate layer 38 is less than 0.1 μm, there may be a problem that sufficient color developability cannot be obtained. If the thickness exceeds 5000 μm, the distance between the electrodes becomes large and a high driving voltage is required. There is a problem to say.

  The refractive index of the entire region of the intermediate layer 38 is preferably in the range of the refractive index of the dispersion medium -0.2 or more and the refractive index of the dispersion medium 42 +0.2 or less, and the refractive index of the dispersion medium -0 It is more preferable that the refractive index is within the range of 0.05 or more and the refractive index of the dispersion medium 42 +0.05 or less, and most preferably the same as the refractive index of the dispersion medium 42.

  If the refractive index of the intermediate layer 38 is within the above range, light scattering caused by the intermediate layer 38 can be further suppressed as compared with the case where the refractive index is outside the above range, so that a clear color display with higher saturation is achieved. Can be done.

  The refractive index can be measured by using a laser measuring instrument, and for particles by the Becke line method, the immersion method, the method of measuring attenuation for each wavelength, the method of measuring the critical angle of refraction, and the like.

  The form of the intermediate layer 38 is not particularly limited as long as it has a hole through which the first particles 36 move and has optical reflection characteristics different from those of the first particles 36, as described above. Particulate members such as inorganic material particles composed of materials such as titanium and zinc oxide, and organic material particles composed of materials such as methyl methacrylate resin, styrene acrylic resin, silicone resin, polytetrafluoroethylene resin ( Hereinafter, the aggregate may be referred to as the third particle 41), or a resin sheet, a nonwoven fabric, or the like may be used.

  In the case where the intermediate layer 38 is configured as an aggregate of the second particles 41, the volume average primary particle size of the second particles 41 is not particularly limited, but the aggregate of the second particles 41 is not limited. When the intermediate layer 38 made of is disposed in a region between the display substrate 18 and the back substrate 20, the volume average primary particle size is such that the first particles 36 can pass through the gap between the adjacent second particles 41. It is desirable to have

  For this reason, the volume average primary particle size of the second particles 41 is desirably 10 times or more of the volume average primary particle size of the first particles 36, and desirably 25 times or more. When the volume average primary particle size of the second particles 41 is less than 10 times the volume average primary particle size of the first particles 36, gaps (holes) between the plurality of second particles 41 constituting the intermediate layer 38 are formed. It may be difficult for the first particles 36 to pass through. The upper limit of the volume average primary particle size of the second particles 41 is not particularly limited, but when the intermediate layer 38 is configured as an aggregate of the second particles 41, the intermediate layer 38 and the display substrate 18 are not separated. In addition, the filling rate of the second particles 41, the number of layers to be laminated, and the like so that a gap of about the volume average primary particle size of the first particles 36 is formed between the intermediate layer 38 and the back substrate 20. You may adjust according to.

  In the present embodiment, the volume average primary particle size of the second particles 41 may be measured in the same manner as the first particles 36.

  Further, when the intermediate layer 38 is formed of a resin sheet or nonwoven fabric, examples of the material constituting the resin sheet or nonwoven fabric include polyethylene, polystyrene, polyester, polyacryl, polypropylene, and polytetrafluoroethylene ( Fluorinated resins such as PTFE) can be applied. Particularly desirable are polypropylene and PTFE resins since the first particles 36 are less likely to adhere. What is necessary is just to comprise as the aggregate | assembly of the fiber which consists of these materials, when comprising the intermediate | middle layer 38 with a nonwoven fabric.

  The porosity of the intermediate layer 38 is preferably 50% or more and 80% or less for the reason that both the passage performance through which the first particles 36 pass and the high color developability of the display medium 12 are compatible.

Further, the average pore diameter of the holes in the intermediate layer 38 is not particularly limited as long as the particles constituting the first particles 36 can pass therethrough, but the average particle diameter of the first particles 36 is the first particles 36. The volume average primary particle size is preferably in the range of 1.2 to 10,000 times, more preferably in the range of 2 to 1,000 times.
When the average pore diameter of the holes of the intermediate layer 38 is less than 1.2 times the volume average primary particle diameter of the first particles 36, each particle constituting the first particles 36 may move through the holes. When it exceeds 10,000 times, there is a case where the gap becomes large and the color development is lowered.

Further, when the intermediate layer 38 is made of a nonwoven fabric, the basis weight of the fibers constituting the nonwoven fabric is good because the passage rate of the first particles 36 is improved and the thickness of the display medium 12 is reduced. The range of 20 g / m ² or more and 100 g / m ² or less is good, and the range of 20 g / m ² or more and 50 g / m ² or less is better.

  The diameter of the fibers constituting the nonwoven fabric is in the range of 0.1 μm to 20 μm, and preferably in the range of 0.1 μm to 3 μm, to ensure a sufficient surface area and physical strength. To preferred.

  Next, the display device 10 and the writing device 13 of the present embodiment will be described.

  As described above, the display device 10 includes the display medium 12 and the writing device 13 for displaying an image on the display medium 12.

The writing device 13 includes a voltage application unit 14, a control unit 16, and an image information acquisition unit 17.
The voltage application unit 14 is connected to the control unit 16 so as to be able to exchange signals, and is connected to the display electrode 24 and the back electrode 30 so as to be able to apply a voltage.

  The image information acquisition unit 17 acquires image information indicating an image to be displayed on the display medium 12 from outside the display device 10 and the writing device 13. As the image information acquisition unit 17, for example, a general method for reading image information recorded on the image recording medium from an image recording medium such as a CD-R, FD (floppy (registered trademark) disk), MD, DVD, etc. And a general communication device for acquiring image information via a wireless or wired communication network can be used.

  The control unit 16 controls the voltage applied from the voltage application unit 14 to the display medium 12 according to the image information acquired by the image information acquisition unit 17. The control unit 16 includes a microcomputer including a CPU 16A, a ROM 16B, a RAM 16C, and a hard disk (not shown). The CPU 16A displays an image on the display medium 12 according to a program stored in the ROM 16B or a hard disk (not shown).

The display medium 12 may be provided so as to be detachable from the writing device 13 or may be fixed while being electrically connected to the writing device 13.
By providing the display medium 12 detachably with respect to the writing device 13, the display medium 12 can be exchanged, and an image can be displayed on a plurality of display media 12 using one writing device 13. .

  Below, the process performed by CPU16A of the control part 16 of the display apparatus 10 provided with the display medium 12 in this Embodiment is demonstrated.

  The CPU 16A of the control unit 16 reads the program indicated by the processing routine shown in FIG. 7 from the ROM 16B or the hard disk in the control unit 16 to execute the process shown in FIG.

  In the processing routine shown in FIG. 7, the case where particles having a characteristic of moving between substrates by an electric field formed between the substrates is used as the first particles 36 enclosed in the display medium 12 will be described. .

  In the present embodiment, in order to simplify the description, the image information acquisition unit 17 acquires information indicating the color of the image displayed in one specific cell of the display medium 12 as the image information. A case where a color based on the image information is displayed in one corresponding cell of the display medium 12 will be described.

  In the present embodiment, electrophoretic voltage information, closing voltage information, and opening voltage information are stored in advance in the ROM 16B.

The electrophoretic voltage information is stored in advance corresponding to the color information indicating the color displayed on the display medium 12.
The electrophoretic voltage information is information indicating a voltage applied between the display substrate 18 and the back substrate 20 in order to display a specific color on the display medium 12, and the first particles 36 in the display medium 12 Information indicating the voltage value, voltage application time (hereinafter referred to as electrophoresis time), polarity, etc. for moving from one of the display substrate 18 and the rear substrate 20 to the other substrate side. Contains. The electrophoretic voltage information is determined by the configuration of the first particles 36, the configuration of the display medium 12, and the like.

  The “polarity” indicates which of the display electrode 24 and the back electrode 30 is a negative electrode (minus electrode) and which is a positive electrode (plus electrode) to apply a voltage.

  The closed voltage information refers to the voltage value and voltage of the voltage applied between the display substrate 18 and the back substrate 20 necessary for changing the connection hole 26B of the hollow structure 26 from the open state to the closed state. This is information indicating the application time (hereinafter referred to as closing time), polarity, and the like. This closing voltage information is determined by the dissociation constant, the Donnan potential, the salt concentration, the oxidation-reduction potential, other characteristics, the configuration of the display medium 12, and the like of the material constituting the connection hole 26B.

  The closing time is, for example, the connection hole 26B that has been in an open state after the voltage having the voltage value included in the closing voltage information is applied between the display electrode 24 and the back electrode 30. The time required for the closed state, which is the smallest possible hole diameter, is shown.

  The opening voltage information is a voltage value of voltage applied between the display substrate 18 and the back substrate 20 and a voltage necessary for changing the connection hole 26B of the hollow structure 26 from the closed state to the open state. This is information indicating application time (hereinafter referred to as opening time), polarity, and the like. This opening voltage information is determined by the dissociation constant, the Donnan potential, the salt concentration, the oxidation-reduction potential, other characteristics, the configuration of the display medium 12, and the like of the material constituting the connection hole 26B.

  The opening time is, for example, the connection hole 26B that has been in a closed state after the voltage having the voltage value included in the opening voltage information is applied between the display electrode 24 and the back electrode 30 and the connection hole 26B takes the closed time. It shows the time required to reach the open state, which is the largest possible hole diameter state.

  The voltage of the voltage for moving the first particles 36 in the display medium 12 from the substrate side of either the display substrate 18 or the back substrate 20 to the other substrate side indicated by the electrophoresis voltage information. The absolute value of the value is based on the absolute value of the voltage value of the voltage applied between the display substrate 18 and the back substrate 20 necessary for changing the connecting hole 26B indicated by the opening voltage information from the closed state to the open state. Is adjusted in advance so as to be a large value.

  The voltage of the voltage for moving the first particles 36 in the display medium 12 from the substrate side of either the display substrate 18 or the back substrate 20 to the other substrate side, as indicated by the electrophoresis voltage information. The absolute value of the value is based on the absolute value of the voltage value of the voltage applied between the display substrate 18 and the back substrate 20 necessary for changing the connecting hole 26B indicated by the closed voltage information from the open state to the closed state. Is adjusted in advance so as to be a large value.

  Further, the voltage value of the voltage applied between the display substrate 18 and the rear substrate 20 necessary for changing the connecting hole 26B indicated by the opening voltage information from the closed state to the open state, and the closing voltage information. The voltage value of the voltage applied between the display substrate 18 and the back substrate 20 necessary for changing the connecting hole 26B from the open state to the closed state is a different value, and preferably the polarities are different. . In the present embodiment, description will be made assuming that the polarities are different.

  The electrophoretic voltage information, the closing voltage information, and the opening voltage information may be measured for each display medium 12 in advance and stored in the ROM 16B in advance.

The CPU 16A of the control unit 16 executes the processing routine shown in FIG.
In step 100, it is determined whether or not the image information acquisition unit 17 has acquired the image information. If the determination is negative, this routine is terminated. If the determination is positive, the process proceeds to step 102.

In step 102, the opening voltage information of the connection hole 26B is read from the ROM 16B.

  In step 104, the color information included in the image information acquired in step 100 is read.

  In the next step 106, electrophoretic voltage information corresponding to the color information read in step 104 is read from the ROM 16A.

  In the next step 108, the aperture voltage information read in step 102 is output to the voltage application unit 14. The voltage application unit 14 that has received the opening voltage information, based on the voltage value, opening time, and polarity of the voltage indicated in the opening voltage information, converts the voltage value with the polarity, the opening time, and the display electrode 24. And between the back electrode 30 and the back electrode 30.

  In the next step 110, after the opening voltage information is output to the voltage applying unit 14 in step 108, it is determined whether or not the opening time included in the opening voltage information has elapsed, and a negative determination is made until affirmative. If the determination is affirmative, the process proceeds to step 112.

  By the processing of Step 108 to Step 110, a voltage corresponding to the opening voltage information is applied from the voltage application unit 14 to the display electrode 24 and the back electrode 30, and the hole diameter of the connection hole 26B of the hollow structure 26 is expanded, so that from the closed state. It changes to an open state.

  In the next step 112, the electrophoretic voltage information read in step 106 is output to the voltage applying unit 14, and in the next step 114, the electrophoresis output to the voltage applying unit 14 in step 112 after the processing in step 112 is completed. It is determined whether or not the electrophoresis time included in the voltage information has elapsed, and the negative determination is repeated until it is affirmed.

  By the processing of Step 112 to Step 114, for example, a voltage for moving to the display substrate 18 side is applied to the display electrode 24 and the back electrode 30, and the first particles 36 dispersed in the dispersion medium 42 are formed. It reaches the display substrate 18 side. At this time, since the connection hole 26B of the hollow structure 26 is in an open state by the processing of step 108 to step 110, the first particles 36 that have reached the display substrate 18 are separated from the back substrate 20 of the display substrate 18. The first space 26A is reached through the connection hole 26B of the hollow structure 26 provided on the opposite surface.

In step 116, the closing voltage information of the connection hole 26 </ b> B is read from the ROM 16 </ b> B, and in the next step 118, the read closing voltage information is output to the voltage application unit 14.
In the next step 120, after the closing voltage information is output to the voltage applying unit 14 in the above step 116, the negative determination is repeated until the aggregation time included in the closing voltage information elapses. move on.

  By the process of step 118 to step 120, the voltage according to the closing voltage information is applied from the voltage application unit 14 to the display electrode 24 and the back electrode 30, thereby reducing the hole diameter of the connection hole 26 </ b> B of the hollow structure 26. It changes from an open state to a closed state. For this reason, it becomes difficult for the first particles 36 present in each first space 26A of the hollow structure 26 to pass through the connection hole 26B, and the first particles 36 are held in the first space 26A.

  In step 122, after outputting a signal indicating that the voltage application to the display medium 12 is stopped to the voltage application unit 14, this routine is finished. The voltage application unit 14 that has received the signal indicating the voltage application stop stops the voltage application to the display medium 12.

  For example, before the processing routine shown in FIG. 7 is executed, the first particles 36 are present on the back substrate 20 side, and the first particles are included in the image information acquired in the processing of step 100 above. When the color information indicating the 36 colors is included, the connection hole 26 </ b> B of the hollow structure 26 is difficult for the first particles 36 to pass through by performing the processing of Step 100 to Step 110. The closed state (see FIG. 8A), which is a state, is changed from the closed state (see FIG. 8B) to the open state (see FIG. 8B) in which the first particles 36 can pass by the expansion of the holes.

  Furthermore, the first particles 36 existing on the back substrate 20 side are electrophoresed in the dispersion medium 42 by executing the processing of the above step 112 to step 114 (see FIG. 8C), It reaches the first space 26A through the connecting hole 26B in the open state of the hollow structure 26 of the display medium 12 (see FIG. 8D).

  Here, by further executing the processing of step 116 to step 120, the connection hole 26 </ b> B of the hollow structure 26 is in an open state (a state in which the first particles 36 can pass due to the narrowing of the hole). 8D) to a closed state (see FIG. 8E), which is a state in which the first particles 36 are difficult to pass.

  Here, as shown in FIG. 8E, the first particles 36 have reached the first space 26A. For this reason, when the connecting hole 26B changes from the open state to the closed state, it becomes difficult for the first particles 36 to pass through the connecting hole 26B, and the first particles 36 that have reached the first space 26A. Is held in the first space 26A. Even if the voltage application by the voltage application unit 14 is stopped in this state, the closed state of the connection hole 26B is maintained, so the first particles 36 that have reached the first space 26A are in the first space 26A. Retained.

In this way, the movement of the first particles 36 between the first spaces 26A of the hollow structure 26 through the connection holes 26B and the movement from the inside of the hollow structure 26 to the outside are suppressed. .
Therefore, the density change of the display medium 12 is suppressed.

On the other hand, when the image information acquired in the processing of step 100 includes color information indicating the color of the intermediate layer 38 of the display medium 12, the processing of steps 102 to 122 is performed. Thus, for example, the connection hole 26B of the hollow structure 26 provided on the display substrate 18 side changes from the closed state shown in FIG. 8E to the open state shown in FIG. 8D. And after this connection hole 26B changes to an open state, the 1st particle | grains 36 currently hold | maintained in the 1st space 26A of the hollow structure 26 are hollow structure via the connection hole 26B in an open state. Electrophoresis is performed outside the body 26 (see FIG. 8C), and further reaches the back substrate 20 side through the holes of the intermediate layer 38 (see FIG. 8B). And then. Furthermore, the connection hole 26B of the hollow structure 26 changes from the open state (see FIG. 8B) to the closed state (see FIG. 8A). Thereby, when visually recognized from the display substrate 18 side, the color of the intermediate layer 38 is visually recognized, and multicolor display becomes possible.
Further, since the connection hole 26B of the hollow structure 26 provided on the display substrate 18 side is closed after the first particles 36 move to the back substrate 20 side, the connection holes 26B move to the back substrate 20 side. The density change of the display medium 12 due to the color of the first particle 36 group is suppressed.

  In the present embodiment, the case where one kind of particles having the same color as the first particles 36 is enclosed between the display substrate 18 and the back substrate 20 has been described. Furthermore, a plurality of types of particles having different colors and different electrophoretic voltage ranges may be enclosed between the substrates. In this case, a voltage for selectively moving the first particles 36 of a type corresponding to the color to be displayed on the display medium 12 is selectively applied, so that multi-color display by a combination of the first particles 36 having different colors is performed. May be realized.

  Also in this case, similarly to the above, the display substrate 18 and the back substrate 20 indicated by the electrophoretic voltage information of each of the plurality of types of first particles 36 are changed from one substrate side to the other. The absolute value of the voltage value of the voltage for moving to the substrate side is between the display substrate 18 and the rear substrate 20 necessary for changing the connecting hole 26B indicated by the opening voltage information from the closed state to the open state. What is necessary is just to adjust beforehand so that it may become a value larger than the absolute value of the voltage value of the voltage to apply.

  Similarly to the above, the display substrate 18 and the back substrate 20 move from one substrate side to the other substrate side indicated by the electrophoretic voltage information of each of the plurality of types of first particles 36. The absolute value of the voltage value for the voltage to be applied is a voltage voltage applied between the display substrate 18 and the rear substrate 20 necessary for changing the connecting hole 26B indicated by the closing voltage information from the open state to the closed state. What is necessary is just to adjust beforehand so that it may become a value larger than the absolute value of a value.

  Further, in this case, electrophoretic voltage information indicating the voltage for moving the first particles 36 according to the target color may be stored in advance in the ROM 16B in association with the corresponding color information.

As described above, according to the display device 10 and the writing device 13 of the present embodiment, the first space 26A arranged at least in the surface direction on the surface facing the back substrate 20 of the display substrate 18; The pore diameter is changed by the application of the electric field stimulus as the first stimulus, and the first space 26A communicates with the outside at least in the opening state having the largest hole diameter, and at least in the opening state, the first space from the outside is provided. 26A, a hollow structure 26 having a connection hole 26B through which the first particles 36 pass so as to enter the interior 26A. After the connection hole 26B is opened by electric field stimulation, the display substrate 18 side A voltage for electrophoresis of the first particles 36 is applied to the first particles 36 so as to reach the first space 26A of the hollow structure 26, and the connection holes 26B are passed through the first particles 36. It is a difficult closing state of.
For this reason, a decrease in image retention of the display medium 12 is suppressed.

  In the present embodiment, the case where the intermediate layer 38 is provided in the display medium 12 has been described. However, unlike the display medium 12A illustrated in FIG. 9, the intermediate layer 38 is not provided. Also good.

  A display device 10A shown in FIG. 9 includes a display medium 12A and a writing device 13. The display medium 12 </ b> A includes the display substrate 18, the back substrate 20, the gap member 34, the dispersion medium 42, the first particles 36, and the hollow structure 26. The display device 10A has the same configuration as the display device 10 except that the display medium 12A does not include the intermediate layer 38 in the configuration of the display medium 12 described above. The same reference numerals are given and detailed description is omitted.

  In the present embodiment, the case where the hollow structure 26 is provided only on the display substrate 18 side of the display medium 12 has been described. However, as shown in FIG. A configuration in which a constraining layer 31 for constraining 36 may be provided.

  A display device 10B shown in FIG. 10 includes a display medium 12B and a writing device 13. The display medium 12B further includes a constraining layer 31 in addition to the configuration of the display medium 12 described above, and the other configurations are the same as those of the display device 10 and the display medium 12, and thus detailed description thereof is omitted. To do.

The constraining layer 31 is stacked on the side of the back substrate 20 facing the display substrate 18.
The constraining layer 31 is a layer for constraining the first particles 36 as long as it can constrain the first particles 36 according to the electric field formed between the substrates.

  Note that, by using the configuration of the display medium 12B, it is possible to suppress a decrease in image retention, and it is possible to suppress a variation in density. Therefore, the constraining layer 31 is not necessarily provided further on the back substrate 20 side. However, the display medium 12B having the constraining layer 31 provided on the back substrate 20 in this manner (see FIG. 10) is compared with the display medium 12 having no constraining layer 31 provided on the back substrate 20. In addition, it is possible to further suppress a decrease in image retention.

  The constraining layer 31 may have such a configuration as long as it has the characteristics described above. For example, the constraining layer 31 may have the same configuration as the hollow structure 26 described above. Moreover, the layer by which the surface treatment for restraining the 1st particle | grains 36 was made may be sufficient.

  As the surface treatment, for example, the surface of the back substrate 20 on the side in contact with the dispersion medium 42 is charged with a charging polarity different from that of the first particles 36 or charged with the same polarity. The surface of the substrate 20 is appropriately selected according to the acting force between the first particles 36 and the surface of the back substrate 20, such as a treatment for controlling surface free energy and adhesiveness.

  For example, when the first particles 36 are charged to the positive electrode, the charging process of the constraining layer 31 is performed when the negative particles are charged to the negative electrode and the first particles 36 are charged to the negative electrode. In order to increase the binding force, it is preferable to use an electrical action of positively charging the positive electrode.

Specifically, this charging treatment is preferably performed by chemical treatment, and for example, it may be modified with an acidic group or a basic group. Specifically, for example, when a positive charge treatment is performed, the treatment is preferably performed using a basic compound, and when a negative charge treatment is performed, the treatment is preferably performed using an acidic compound. For example, when the treatment is performed with a basic compound, a basic group (for example, NH ₃ ⁺ ) is arranged on the surface and is positively charged. On the other hand, when the treatment is performed with an acidic compound, acidic groups (for example, SO ₃ ⁻ and COO ⁻ ) are arranged on the surface and are negatively charged.

As the basic compound for performing the positive charging treatment, for example, the following compounds can be used, but are not limited thereto.
・ Polylylamine hydrochloride
・ Poly (p-phenylene vinylene)
・ Poly (p-methylpyridinium vinylene)
・ Protonated poly (p-pyridine vinylene)
・ Poly (2-N-methylpyridinium acetylene)
・ Γ-Aminopropytriethoxysilane
N- [3- (trimethoxysilyl) propyl] ethylenediamine

As the acidic compound for performing the negative charging treatment, for example, the following compounds can be used, but are not limited thereto.
・ Sulfonated polyline
Poly (thiophene-3-acetic-acid)
・ Sulfonated polystyrene
・ Polyvinylsulfate potassium salt
Poly-4-vinylbenzyl- (N, N-diethyl-N-methyl-) ammonium iodide
・ Carboxyethylsilanetriol

  In order to process a substrate using these compounds, for example, it can be performed as follows. These compounds are dissolved in alcohol such as methanol, ethanol, and IPA, water, or a mixture of alcohol and water so that the concentration is 0.01 wt% or more and 10 wt% or less. Immerse. Thereafter, excess liquid adhering to the substrate is washed away with alcohol, water, or a mixture of alcohol and water. Thereafter, the substrate can be processed by drying at 100 ° C. to 150 ° C. for 5 minutes to 60 minutes. When the compound is dissolved in alcohol, water, or a mixture of alcohol and water, it is also effective to add hydrochloric acid, acetic acid, aqueous ammonia or the like in an amount of 0.01 wt% to 10 wt%.

Depending on the surface to be treated, a basic compound can be treated after treatment with an acidic compound. Of course, the reverse is possible. Furthermore, in addition to the silane coupling agent as described above, it is also desirable to coat the surface using a polymer having an acidic group or a basic group as described above.
Other surface treatments for the constraining layer 31 include fluorine compounds (for example, silane coupling agents having a fluorine substituent) and long chain alkyl compounds (for example, silane coupling agents having a long chain alkyl substituent). It is also desirable to react or coat various polymers such as fluorine-based polymers.

  The constraining layer 31 described above is more preferably the same configuration as the hollow structure 26 described above from the viewpoint of image retention.

  By providing the constraining layer 31 described above, an electric field is formed between the display substrate 18 and the back substrate 20 to restrain the first particles 36 that have reached the back substrate 20 side to the back substrate 20 side. Therefore, it is possible to further suppress a decrease in image retention of the display medium 12B.

  In the processing routine shown in FIG. 7, as the first particles 36 enclosed in the display medium 12, the first particles 36 having a characteristic of moving between the substrates by an electric field formed between the substrates are used. As described above, the characteristics of moving between the substrates by the electric field formed between the substrates, and agglomeration in the first space 26A of the hollow structure 26 due to the repulsive force between the inner wall of the hollow structure 26 and the particle surface. What has the characteristic further hold | maintained in the state made | formed may be used.

  In this case, when the processing routine shown in FIG. 7 is executed, for example, before the processing routine is executed, the first particles 36 are present on the back substrate 20 side, and When the image information acquired in the process of step 100 includes color information indicating the color of the first particle 36, the process of steps 100 to 110 is performed as shown in FIG. As a result, the connection hole 26B of the hollow structure 26 passes through the first particle 36 from the closed state (see FIG. 11A), which is a state in which the passage of the first particle 36 is difficult due to the expansion of the hole. It changes to the opening state (refer FIG. 11 (B)) which is the state of this.

  Furthermore, the first particles 36 existing on the back substrate 20 side are electrophoresed in the dispersion medium 42 by executing the processing of the above step 112 to step 114 (see FIG. 11C). It reaches the first space 26A through the connection hole 26B in the open state of the hollow structure 26 of the display medium 12 (see FIG. 11D).

  Here, the first particles 36 that have reached the first space 26 </ b> A are formed in the first space 26 </ b> A by the repulsive force between the inner wall of the hollow structure 26 and the surface of the first particle 36. The first space 26A is held in an aggregated state.

  Furthermore, by performing the processing of step 116 to step 120, the connection hole 26B of the hollow structure 26 is in an open state (FIG. 11 (FIG. 11 ()) in which the first particles 36 can pass due to the narrowing of the hole. D)) to a closed state (see FIG. 11E), in which it is difficult for the first particles 36 to pass through.

  Here, as shown in FIG. 11E, the first particles 36 reach the first space 26A and are in an aggregated state. For this reason, even when the connecting hole 26B is in the open state, the first particles 36 that have reached the first space 26A are prevented from moving to the outside through the connecting hole 26B. Furthermore, since the connection hole 26B changes from the open state to the closed state, it becomes more difficult for the first particles 36 to pass through the connection hole 26B, and the first particles 36 that have reached the first space 26A. Is held in the first space 26A. Even if the voltage application by the voltage application unit 14 is stopped in this state, the closed state of the connection hole 26B is maintained, so the first particles 36 that have reached the first space 26A are in the first space 26A. Retained.

Thus, since the first particles 36 are held in an aggregated state in the first space 26 </ b> A of the hollow structure 26, the substrate of the display substrate 18 and the back substrate 20 is used as the first particles 36. Along with the property of moving between the substrates by the electric field formed between them, it is held in an aggregated state in the first space 26A of the hollow structure 26 by the repulsive force between the inner wall of the hollow structure 26 and the particle surface. By having the characteristics, the first particles 36 can move between the first spaces 26A of the hollow structure 26 via the connection holes 26B, or can move from the inside of the hollow structure 26 to the outside. Is suppressed.
Therefore, the density change of the display medium 12 is further suppressed.

  In the above-described embodiment, the hollow structure 26 has been described as a case where the hole diameter of the connection hole 26B is changed by the action of an electric field as a first stimulus. The hole diameter of 26B may be changed.

In this case, the dispersion medium 42 may be any medium that causes a pH change by electrolysis. For example, water, an organic solvent, or a mixture thereof is used, and the hollow structure 26 has a connection hole 26B. What is necessary is just to use the material which responds by the change of pH of the dispersion medium 42 as a stimulus response material used in order to adjust the tubular body 27A.
Here, the change in pH of the dispersion medium 42 is caused by electrolysis of the dispersion medium 42 caused by an electric field acting on the dispersion medium 42. The change in the hole diameter of the connecting hole 26B is due to the change in pH due to the electrolysis of the dispersion medium 42. If the material constituting the tubular body 27A constituting the connecting hole 26B has, for example, an acidic group, the volume increases as the pH increases. It becomes an open state and becomes a closed state due to a decrease in volume due to a decrease in pH. On the other hand, if the material constituting the tubular body 27A constituting the connecting hole 26B has, for example, a basic group, the volume decreases with increasing pH and becomes a closed state, and becomes open when the volume increases with decreasing pH.

  In order to change the connection hole 26B to an open state or a closed state by such a change in pH of the dispersion medium 42, a predetermined amount for electrolyzing the dispersion medium 42 is provided between the display substrate 18 and the back substrate 20. The voltage value and voltage application time of the voltage applied between the display substrate 18 and the back substrate 20 in order to form this electric field are determined depending on the material constituting the tubular body 27A, the dissociation constant, Although it depends on the ion concentration, temperature, etc., it may be measured in advance when the display medium 12 is configured.

  Specifically, as the stimulus-responsive material constituting the tubular body 27A that forms the connecting hole 26B whose pore diameter is changed by the action of pH, an electrolyte polymer material is preferable, and poly (meth) acrylic acid is used. Cross-linked products and salts thereof, cross-linked products of (meth) acrylic acid and (meth) acrylamide, hydroxyethyl (meth) acrylate, (meth) acrylic acid alkyl ester and the like, salts thereof, cross-linked polymaleic acid, Its salts, cross-linked products of salts of maleic acid and (meth) acrylamide, hydroxyethyl (meth) acrylate, alkyl (meth) acrylate, etc., salts thereof, cross-linked polyvinyl sulfonic acid and vinyl sulfonic acid ( (Meth) acrylamide, hydroxyethyl (meth) acrylate, (meth) acrylic acid alkyl ester, etc. Of crosslinked copolymer of polyvinylbenzene, crosslinked product of polyvinylbenzenesulfonic acid and its salt, copolymer of vinylbenzenesulfonic acid and (meth) acrylamide, hydroxyethyl (meth) acrylate, (meth) acrylic acid alkyl ester, etc. Cross-linked products and salts thereof, cross-linked products and salts of polyacrylamide alkyl sulfonic acids, and cross-linked copolymers of acrylamide alkyl sulfonic acids with (meth) acrylamide, hydroxyethyl (meth) acrylate, (meth) acrylic acid alkyl esters, etc. Products and their salts, crosslinked products of polydimethylaminopropyl (meth) acrylamide and its hydrochloride, dimethylaminopropyl (meth) acrylamide and (meth) acrylic acid, (meth) acrylamide, hydroxyethyl (meth) acrylate, (meth) Alkyl acrylate Cross-linked copolymers of stellite and the like, quaternized products and salts thereof, cross-linked products of polydimethylaminopropyl (meth) acrylamide and polyvinyl alcohol, quaternized products and salts thereof, polyvinyl alcohol and poly (meta) ) Cross-linked products of complexes with acrylic acid and salts thereof, cross-linked products of carboxyalkyl cellulose salts, partially hydrolyzed products of cross-linked products of poly (meth) acrylonitrile, and salts thereof.

  Among these, a crosslinked product of poly (meth) acrylic acid, a salt thereof, or a derivative thereof is preferably used for reasons of cost and handling.

  Any known solvent can be used as the solvent for the stimulus-responsive material as long as it causes a pH change by electrolysis. Specifically, for example, water, an organic solvent, a mixture thereof, or the like is used.

  The colloidal particle structure is produced by producing the stimulation response material that responds by the action of pH as the material of the hollow structure 26 described above except that the tubular structure 27A that constitutes the connection hole 26B is used. 29 (refer to FIG. 5), and a negative hollow structure having a first space 26A having the same shape as a first stimulus and a connecting hole 26B formed by a tubular body 27A whose pore diameter is changed by pH change as a first stimulus. A body 26 is produced.

  The method for producing the hollow structure 26 is not limited to the above method, and any method can be used as long as the hollow structure 26 can be manufactured using the hollow structure having the connection hole 26B and the first space 26A. It may be used.

  Similarly, in the case of using the hollow structure 26 in which the hole diameter of the connection hole 26B changes due to such a change in pH, the display apparatus 10 that can suppress the change in concentration by executing the processing routine shown in FIG. Is provided.

  Specifically, as the closing voltage information, the voltage value of the voltage applied between the display substrate 18 and the back substrate 20 necessary for changing the connection hole 26B of the hollow structure 26 from the open state to the closed state. The display substrate 18 and the back substrate necessary for changing the connection hole 26B of the hollow structure 26 from the open state to the closed state by electrolysis of the dispersion medium 42 instead of the information indicating the closing time, polarity, etc. Information indicating the voltage value, closing time, polarity, and the like of the voltage applied to 20 is stored in the ROM 16B in advance, and the connection hole 26B of the hollow structure 26 is changed from the closed state to the open state as opening voltage information. The hollow structure is obtained by electrolysis of the dispersion medium 42 instead of information indicating the voltage value, the closing time, the polarity, and the like of the voltage applied between the display substrate 18 and the back substrate 20 necessary for the change. Information indicating the voltage value, closing time, polarity, etc. of the voltage applied between the display substrate 18 and the back substrate 20 necessary for changing the six connecting holes 26B from the closed state to the open state is stored in advance in the ROM 16B. You can memorize it.

  In this way, similarly to the case of using the hollow structure 26 in which the hole diameter of the connection hole 26B changes due to the change in pH, the change in concentration can be suppressed by executing the processing routine shown in FIG. A display device 10 is provided.

(Second Embodiment)
In the first embodiment, as the first particles 36, particles having a characteristic of moving between the substrates by an electric field formed between the display substrate 18 and the back substrate 20, or the display substrate 18 and the back surface. Along with the property of moving between the substrates by the electric field formed between the substrate 20 and the substrate, the particles are aggregated in the first space 26A of the hollow structure 26 by the repulsive force between the inner wall of the hollow structure 26 and the particle surface. The case of using particles having the characteristic of being held in a state has been described. In the present embodiment, the first particles 36 have a characteristic of moving between the substrates by an electric field formed between the display substrate 18 and the back substrate 20, and the display substrate 18 and the back surface as a second stimulus. A case will be described in which the first particles 36 having a property of being aggregated or dispersed by the action of an electric field formed between the substrate 20 and the substrate 20 are used.

  Since the present embodiment has the same configuration as that of the above embodiment, the same portions are denoted by the same reference numerals and detailed description thereof is omitted.

  As shown in FIG. 12, the display device 10C according to the present embodiment includes a display medium 12C and a writing device 13C.

  The writing device 13 </ b> C includes a voltage application unit 14, an image information acquisition unit 17, and a control unit 50. The voltage application unit 14 and the image information acquisition unit 17 are connected to the control unit 50 so as to be able to exchange signals.

  The display medium 12C corresponds to the display medium of the present invention, the display device 10C corresponds to the display device of the present invention, and the writing device 13C corresponds to the writing device of the present invention. The voltage application unit 14 corresponds to voltage application means of the display device and writing device of the present invention.

  The display medium 12C includes a display substrate 18 serving as an image display surface, a rear substrate 20 that faces the display substrate 18 with a gap, and maintains a predetermined distance between the substrates, and a gap between the display substrate 18 and the rear substrate 20. The gap member 34 partitioned into a plurality of cells, the dispersion medium 42, the hollow structure 26, the intermediate layer 38, and the first particles 36A enclosed in each cell are configured.

As the first stimulus for changing the hole diameter of the connection hole 26B of the hollow structure 26, the case where the action of an electric field is used will be described as in the first embodiment.
That is, in the second embodiment, the connection hole 26B of the hollow structure 26 changes to an open state or a closed state by the action of an electric field as a first stimulus.

  The first particles 36A used in the present embodiment move between the substrates by the electric field formed between the substrates, and as a second stimulus, the electric field formed between the display substrate 18 and the back substrate 20. It has the property of aggregating or dispersing by the action of.

  The aggregation and dispersion in the dispersion medium 42 due to the action of the electric field of the first particles 36A is caused by applying an electric field to the material constituting the surface (surface) of at least the first particle 36A in contact with the dispersion medium 42. This is caused by increasing the hydrophilicity or increasing the hydrophobicity of the first particles 36A by the oxidation-reduction reaction of the material constituting the surface.

  For this reason, when the material constituting the surface of the first particle 36A by applying an electric field is dispersed in the hydrophobic dispersion medium 42, an oxidation or reduction reaction is performed, and the particle is charged to increase the hydrophilicity. In this case, the first particles 36A aggregate. Conversely, when the first particles 36A dispersed in the charged state in the hydrophilic dispersion medium 42 are oxidized or reduced, the first particles 36A are dispersed when the charged state is weakened and the hydrophobicity is increased. .

  The voltage value and voltage application time applied between the display substrate 18 and the back substrate 20 to cause this oxidation-reduction reaction depend on the oxidation-reduction potential of the material constituting the surface of the first particle 36A. Can be determined in advance.

  When electric charge is present on the surface of the first particle 36A, an electric double layer is formed by counter ions and solvation. Depending on the type of charge and the conditions of the dispersion medium, when a high voltage above a certain level is applied, the electric double layer is stripped and the surface charge of the particles is exposed, resulting in unstable dispersion and aggregation. To do.

  In order to form the first particles 36A that are dispersed or aggregated by the action of the electric field as the second stimulus, the particles moving between the substrates by the action of the electric field described in the first embodiment are used. What is necessary is just to further modify the surface of the adjusted first particle 36 with a material that is redox active.

  Examples of the redox active materials include ferrocene derivatives, metal complexes such as cobalt cenium and ruthenium, transition metals, fullerene derivatives, porphyrins, expanded porphyrins, pyrrole compounds, phenothiazines, viologen derivatives, phenothiazine derivatives, thiophene compounds, anilines. Compounds, carbazole derivatives, tetrathiafulvalene derivatives, diamine compounds, phthalocyanine compounds, hydrazone compounds, oxadiazole derivatives, perylene derivatives, naphthalene derivatives, and the like.

  As a method for modifying the particle surface with a redox active material, introduction of an active group by a coupling agent or the like, surface activation by plasma discharge, corona discharge, X-ray irradiation, or the like may be used.

Any conventionally known method may be used as a method for producing the first particles 36A that are in an aggregated state or dispersed state by the action of such an electric field. For example, as described in JP-A-7-325434, a resin, a pigment, and a charge control agent are weighed so as to have a predetermined mixing ratio, and after the resin is heated and melted, the pigment is added, mixed, dispersed, and cooled. Then, a method of preparing particles using a pulverizer such as a jet mill, a hammer mill, a turbo mill, etc., and then dispersing the obtained particles in a dispersion medium can be used. Also, particles containing a charge control agent are prepared by polymerization methods such as suspension polymerization, emulsion polymerization, dispersion polymerization, coacervation, melt dispersion, emulsion aggregation, and then dispersed in a dispersion medium. A particle dispersion may be prepared. Furthermore, the resin, the colorant, the charge control agent, and the dispersion can be plasticized, the dispersion medium does not boil, and the temperature is lower than the decomposition point of the resin, the charge control agent and / or the colorant. There is a method using an appropriate apparatus capable of dispersing and kneading the raw material of the medium. Specifically, the pigment, the resin, and the charge control agent are heated and melted in a dispersion medium with a meteor mixer, a kneader, etc., and the molten mixture is cooled with stirring using the temperature dependence of the solvent solubility of the resin. Solidify / precipitate to produce particles.
Then, the surface of the produced particles may be modified with the redox-active material to adjust the first particles 36 that are in an aggregated state or a dispersed state by the action of an electric field.

  Furthermore, the above raw materials are put into a suitable container equipped with granular media for dispersion and kneading, for example, a heated vibration mill such as an attritor or a heated ball mill, and the container is placed in a preferred temperature range, for example, 80 A method of dispersing and kneading at a temperature of from 160 to 160 ° C. can be used. As granular media, steels such as stainless steel and carbon steel, alumina, zirconia, silica and the like are preferably used. In order to produce particles by this method, a raw material that has been sufficiently fluidized is dispersed in a container using granular media, and then the dispersion medium is cooled to precipitate a resin containing a colorant from the dispersion medium. The granular media generates a shear and / or impact to reduce the particle size while maintaining a motion state during and after cooling. Then, by modifying the surface of the produced particles with the redox-active material, the first particles 36A that are in an aggregated state or a dispersed state by the action of an electric field may be adjusted.

  The change in display color in the display medium 12C is caused by the movement of the plurality of first particles 36A in the dispersion medium 42 in the dispersion medium 42.

  Since the movement of the first particles 36A by the electric field in the dispersion medium 42 and the method for adjusting the migration voltage range are the same as those of the first particles 36 described in the first embodiment, detailed description thereof is omitted. To do.

  In the present embodiment, the case where only the first particle 36A, that is, one color particle is encapsulated in the display medium 12C will be described. However, the present invention is not limited to such a form. A plurality of types of particles having different voltage ranges may be enclosed. In this case, the first particles 36A may be adjusted in advance so that the electrophoretic voltage ranges described above are different for each type (each color) of the plurality of types of first particles 36A. In this way, by applying a voltage in a specific electrophoretic voltage range between the substrates, the first particles 36A of the color to be moved can be selectively moved between the substrates, and the first particles Multicolor display by movement between the substrates of 36A becomes possible.

  In addition, about preferable content (weight%) of the 1st particle | grains 36A with respect to the total mass in a cell, and a preferable volume average primary particle size, it is the same as the 1st particle | grains 36 demonstrated in the said 1st Embodiment. Since there is, explanation is omitted.

Next, the display device 10C and the writing device 13C of the present embodiment will be described.
As described above, the display device 10C includes the display medium 12C and the writing device 13C for displaying an image on the display medium 12C.

The writing device 13 </ b> C includes a voltage application unit 14, a control unit 50, and an image information acquisition unit 17.
The voltage application unit 14 is connected to the control unit 50 so as to be able to send and receive signals, and is connected to the display electrode 24 and the back electrode 30 so as to be able to apply a voltage.

  The image information acquisition unit 17 acquires image information indicating an image to be displayed on the display medium 12C from the outside of the display device 10C and the writing device 13C.

  The control unit 50 controls the voltage applied from the voltage application unit 14 to the display medium 12C according to the image information acquired by the image information acquisition unit 17. The control unit 50 includes a microcomputer including a CPU 50A, a ROM 50B, a RAM 50C, and a hard disk (not shown). The CPU 50A displays an image on the display medium 12C according to a program stored in the ROM 50B or a hard disk (not shown).

The display medium 12C may be provided so as to be detachable from the writing device 13C, or may be fixed while being electrically connected to the writing device 13C.
By providing the display medium 12C so as to be detachable from the writing device 13C, the display medium 12C can be replaced, and an image can be displayed on a plurality of display media 12C using one writing device 13C. .

  Below, the process performed by CPU50A of the control part 50 of 10 C of display apparatuses provided with the display medium 12C in this Embodiment is demonstrated.

  The CPU 50A of the control unit 50 reads the program shown by the processing routine shown in FIG. 13 from the ROM 50B or the hard disk in the control unit 50, thereby executing the process shown in FIG.

  In the present embodiment, in order to simplify the description, the image information acquisition unit 17 acquires information indicating the color of the image displayed in one specific cell of the display medium 12 as the image information. A case where a color based on the image information is displayed in one corresponding cell of the display medium 12 will be described.

  In the present embodiment, electrophoretic voltage information, closing voltage information, opening voltage information, distributed voltage information, and aggregation voltage information are stored in the ROM 50B in advance.

The electrophoretic voltage information is stored in advance corresponding to the color information indicating the color displayed on the display medium 12C.
The electrophoretic voltage information is information indicating a voltage applied between the display substrate 18 and the back substrate 20 in order to display a specific color on the display medium 12C, and the first particles 36A in the display medium 12 Information indicating the voltage value, voltage application time (hereinafter referred to as electrophoresis time), polarity, etc. for moving from one of the display substrate 18 and the rear substrate 20 to the other substrate side. Contains. The electrophoretic voltage information is determined by the configuration of the first particle 36A, the configuration of the display medium 12C, and the like.

  The “polarity” indicates which of the display electrode 24 and the back electrode 30 is a negative electrode (minus electrode) and which is a positive electrode (plus electrode) to apply a voltage.

  Since the closing voltage information and the opening voltage information have been described in the first embodiment, description thereof will be omitted.

  The dispersion voltage information is information indicating the voltage value, voltage application time (hereinafter referred to as dispersion time), polarity, and the like necessary for making the first particles 36A dispersed in the dispersion medium 42. . This dispersion voltage information is determined by the oxidation-reduction potential of the material constituting the surface of the first particle 36A, other characteristics of the first particle 36A, the configuration of the display medium 12C, and the like.

  The dispersion time is, for example, that the voltage of the voltage value included in the dispersion voltage information is applied between the display electrode 24 and the back electrode 30, and then the first particles 36 </ b> A are in the open state of the hollow structure 26. The time required for the dispersion state to be able to pass through a certain connection hole 26B is shown.

  The aggregation voltage information is information indicating the voltage value, voltage application time (hereinafter referred to as aggregation time), polarity, and the like necessary for bringing the first particles 36A into the aggregation state in the dispersion medium 42. It is. This aggregation voltage information is determined by the oxidation-reduction potential of the material constituting the surface of the first particle 36A, the other configuration of the first particle 36A, the configuration of the display medium 12, and the like.

  The aggregation time refers to, for example, the first particle 36 </ b> A of the hollow structure 26 after the voltage having the voltage value included in the aggregation voltage information is applied between the display electrode 24 and the back electrode 30. It shows the time required to reach the aggregated state to the extent that it is difficult to aggregate and pass through the connecting hole 26B in the open state in the space 26A.

  The absolute value of the voltage applied between the display substrate 18 and the back substrate 20 required to change the connecting hole 26B indicated by the opening voltage information from the closed state to the open state is the electric value. The absolute value of the voltage value of the voltage for moving the first particle 36 </ b> A in the display medium 12 </ b> C from one of the display substrate 18 and the back substrate 20 to the other substrate side indicated by the migration voltage information. Is adjusted in advance so as to be a smaller value.

  The absolute value of the voltage value of the voltage applied between the display substrate 18 and the back substrate 20 required for changing the connecting hole 26B indicated by the opening voltage information from the closed state to the open state is the first value. The particle 36A is adjusted in advance so as to have a value smaller than the absolute value of the voltage required to change the particle 36A from the aggregated state to the dispersed state.

  Furthermore, the absolute value of the voltage required to change the first particles 36A from the aggregated state to the dispersed state is indicated by the electrophoretic voltage information, and the first particles 36A in the display medium 12C are connected to the display substrate 18 and the back surface. The absolute value of the voltage value of the voltage for moving from any one of the substrates 20 to the other substrate side is adjusted in advance so as to be a smaller value.

  Further, the absolute value of the voltage required to change the first particles 36A from the dispersed state to the aggregated state is indicated by the electrophoretic voltage information in the first particles 36A in the display medium 12C. The voltage is adjusted in advance so as to be larger than the absolute value of the voltage value of the voltage for moving from one of the substrates to the other substrate.

  The absolute value of the voltage value of the voltage applied between the display substrate 18 and the back substrate 20 required to change the connecting hole 26B indicated by the closed voltage information from the open state to the closed state is the first value. It is adjusted in advance so as to have a value larger than the absolute value of the voltage required to change the particles 36A from the dispersed state to the aggregated state.

  Furthermore, the absolute value of the voltage value of the voltage applied between the display substrate 18 and the rear substrate 20 necessary for changing the connecting hole 26B indicated by the closed voltage information from the open state to the closed state is the display medium 12C. The first particles 36 </ b> A in the inside of the display substrate 18 and the rear substrate 20 are previously set to have a value larger than the absolute value of the voltage value for moving from one substrate side to the other substrate side. It has been adjusted.

  The electrophoretic voltage information, the closing voltage information, the opening voltage information, the dispersion voltage information, and the aggregation voltage information may be measured in advance for each display medium 12 and stored in the ROM 50B in advance.

In the CPU 50A of the control unit 50, the processing routine shown in FIG.
In step 200, it is determined whether or not the image information acquisition unit 17 has acquired image information. If the determination is negative, this routine is terminated. If the determination is affirmative, the process proceeds to step 202.

In step 202, the opening voltage information of the connection hole 26B is read from the ROM 50B.

  In step 204, the color information included in the image information acquired in step 200 is read.

  In the next step 206, electrophoretic voltage information corresponding to the color information read in step 204 is read from the ROM 50A.

  In the next step 208, the distributed voltage information is read from the ROM 50B.

  In the next step 210, the aperture voltage information read in step 210 is output to the voltage application unit 14. The voltage application unit 14 that has received the opening voltage information, based on the voltage value, opening time, and polarity of the voltage indicated in the opening voltage information, converts the voltage value with the polarity, the opening time, and the display electrode 24. And between the back electrode 30 and the back electrode 30.

  In the next step 212, after the opening voltage information is output to the voltage applying unit 14 in step 210, it is determined whether or not the opening time included in the opening voltage information has elapsed, and a negative determination is made until affirmative. If the determination is affirmative, the process proceeds to step 214.

  As a result of the processing of Step 210 to Step 212, a voltage corresponding to the opening voltage information is applied from the voltage application unit 14 to the display electrode 24 and the back electrode 30, thereby expanding the diameter of the connection hole 26B of the hollow structure 26. It changes from a closed state to an open state.

  In step 214, the distributed voltage information read in step 208 is output to the voltage application unit 14. The voltage application unit 14 that has received the dispersion voltage information displays the voltage value with the polarity, the electrophoresis time, and the display based on the voltage value, the electrophoresis time, and the polarity of the voltage indicated in the dispersion voltage information. Applied between the electrode 24 and the back electrode 30.

  In the next step 216, after the distributed voltage information is output to the voltage applying unit 14 in step 214, it is determined whether or not the dispersion time included in the distributed voltage information has elapsed, and a negative determination is made until affirmative. If the determination is affirmative again, the process proceeds to step 218.

  By applying the voltage according to the distributed voltage information from the voltage application unit 14 to the display electrode 24 and the back electrode 30 by the processing of Step 214 to Step 216, the voltage exists between the display substrate 18 and the back substrate 20. The first particles 36A are dispersed in the dispersion medium 42.

  In the next step 218, the electrophoretic voltage information read in step 206 is output to the voltage application unit 14, and in the next step 220, the electrophoresis output to the voltage application unit 14 in step 218 from the end of the processing in step 218. It is determined whether or not the electrophoresis time included in the voltage information has elapsed, and the negative determination is repeated until it is affirmed.

  By the processing of Step 218 to Step 220, for example, a voltage for moving to the display substrate 18 side is applied to the display electrode 24 and the back electrode 30, and the first particles 36A dispersed in the dispersion medium 42 are produced. It reaches the display substrate 18 side. At this time, since the connection holes 26B of the hollow structure 26 are in an open state by the processing of Step 210 to Step 212, the first particles 36A that have reached the display substrate 18 are separated from the back substrate 20 of the display substrate 18. The first space 26A is reached through the connection hole 26B of the hollow structure 26 provided on the opposite surface.

In the next step 222, the particle aggregation voltage information is read from the ROM 50 </ b> B, and in the next step 224, the read particle aggregation voltage information is output to the voltage application unit 14.
In the next step 228, after the particle aggregation voltage information is output to the voltage application unit in step 224, a negative determination is repeated until the aggregation time included in the particle aggregation voltage information elapses. Proceed to

  By executing the processing of step 224 to step 228, the first particles 36A that have reached the first space 26A are aggregated in the first space 26A of the hollow structure 26.

In the next step 230, the closing voltage information of the connection hole 26 </ b> B is read from the ROM 50 </ b> B, and in the next step 232, the read closing voltage information is output to the voltage application unit 14.
In the next step 234, after the closing voltage information is output to the voltage applying unit 14 in the above step 232, the negative determination is repeated until the aggregation time included in the closing voltage information elapses. move on.

  By applying the voltage corresponding to the closing voltage information from the voltage application unit 14 to the display electrode 24 and the back electrode 30 by the processing of Step 232 to Step 234, the hole diameter of the connection hole 26B of the hollow structure 26 is narrowed. It changes from an open state to a closed state. For this reason, the first particles 36A present in an aggregated state in each first space 26A of the hollow structure 26 are further difficult to pass through the coupling hole 26B, and are retained in the first space 26A. It becomes a state.

  In step 236, after outputting a signal indicating that the voltage application to the display medium 12C is stopped to the voltage application unit 14, this routine is finished. The voltage application unit 14 that has received the signal indicating the voltage application stop stops the voltage application to the display medium 12C.

  For example, before the processing routine shown in FIG. 13 is executed, the first particles 36A exist on the back substrate 20 side, and the first particles are included in the image information acquired in the processing of step 200 described above. When the color information indicating the color of 36A is included, the processing of Step 200 to Step 212 is performed, so that the connection hole 26B of the hollow structure 26 has the first particle 36A due to the expansion of the hole. From the closed state (see FIG. 14A), which is a difficult state for the passage of the first particle 36A, to the open state (see FIG. 14B) in which the first particles 36A can pass.

  Furthermore, the first particles 36 </ b> A are dispersed in the dispersion medium 42 by executing the processing of step 214 to step 216.

  Then, by executing the processing of step 218 to step 220, the first particles 36A existing on the back substrate 20 side are electrophoresed in the dispersion medium 42, and the hollow structure 26 of the display medium 12C. The first space 26A is reached through the connection hole 26B in the open state (see FIG. 14C).

Next, by executing the processing from step 222 to step 228, the first particles 36A that have reached the first space 26A are aggregated in the first space 26A (FIG. 14 ( D)).
Thus, since the first particles 36A are in an aggregated state in the first space 26A, the first particles 36A in the aggregated state move to the outside of the hollow structure 26 through the connection holes 26B. It is suppressed.

  Furthermore, the processing of step 230 to step 234 is performed, so that the connection hole 26B of the hollow structure 26 has the first particles 36 (first particles 36 that are not in an agglomerated state) due to the narrowing of the holes. The state changes from an open state (see FIG. 14D), which allows passage, to a closed state (see FIG. 14E), in which passage of the first particles 36A that are not in an aggregated state is difficult. .

  Here, as shown in FIG. 14E, the first particles 36A have reached the first space 26A. For this reason, when the connection hole 26B changes from the open state to the closed state, it becomes difficult for the first particles 36A to pass through the connection hole 26B, and the first particles 36A that have reached the first space 26A. Is held in the first space 26A. Even if the voltage application by the voltage application unit 14 is stopped in this state, the closed state of the connection hole 26B is maintained, so the first particles 36A that have reached the first space 26A are in the first space 26A. Retained. Furthermore, since the first particles 36A are in an aggregated state in the first space 26A due to the stimulation of the electric field as the second stimulus, the first particles 36A are more stable. It is held in the first space 26A.

  For this reason, it is further suppressed that the first particles 36A move between the first spaces 26A of the hollow structure 26 via the connecting holes 26B and move from the inside of the hollow structure 26 to the outside. . Therefore, the density change of the display medium 12 is suppressed.

(Third embodiment)
In the first embodiment and the second embodiment, the case where the connection hole 26B of the hollow structure 26 is changed to the open state or the closed state by the action of an electric field has been described as the first stimulus. . In the present embodiment, a case will be described in which the connection hole 26B of the hollow structure 26 changes to an open state or a closed state by the action of heat as a first stimulus.

  Since the present embodiment has the same configuration as that of the above embodiment, the same portions are denoted by the same reference numerals and detailed description thereof is omitted.

  As shown in FIG. 15, the display device 60 according to the present embodiment includes a display medium 62 and a writing device 64.

  The writing device 64 includes a voltage application unit 14, an image information acquisition unit 17, and a control unit 67. The voltage application unit 14 and the image information acquisition unit 17 are connected to the control unit 67 so as to be able to exchange signals.

  The display medium 62 corresponds to the display medium of the present invention, the display device 60 corresponds to the display device of the present invention, and the writing device 64 corresponds to the writing device of the present invention. The voltage application unit 14 corresponds to voltage application means of the display device and writing device of the present invention.

  The display medium 62 includes a display substrate 18 that serves as an image display surface, a rear substrate 20 that faces the display substrate 18 with a gap, and holds a predetermined distance between the substrates, and a gap between the display substrate 18 and the rear substrate 20. The gap member 34 partitioned into a plurality of cells, the dispersion medium 42, the hollow structure 90A, the intermediate layer 38, and the first particles 36 enclosed in each cell are configured.

  Further, a heating member 68 and a temperature detection unit 69 are provided on the surface of the back substrate 20 of the display medium 62 opposite to the surface facing the display substrate 18.

  The heating member 68 is a device for applying heat between the display substrate 18 and the back substrate 20, and a general heater, Peltier element, or the like can be used. The heating member 68 is connected to the control unit 67 so as to be able to send and receive signals, and heats the display substrate 18 and the back substrate 20 or releases the heating under the control of the control unit 67. In addition, laser, condensing, ultrasonic irradiation, etc. can be used as appropriate as other heating methods.

The temperature detection unit 69 is a temperature sensor for measuring the temperature between the display substrate 18 and the back substrate 20 and can use a general temperature sensor, and is connected to the control unit 67 so as to be able to send and receive signals. ing.
In the example illustrated in FIG. 15, the temperature detection unit 69 is described as being provided on the heating member 68, but is provided at a position where the temperature between the display substrate 18 and the back substrate 20 can be measured. However, the position is not limited to such a position. For example, the gap member 34 may be provided.

In the present embodiment, the case where the heating member 68 is provided integrally with the display medium 62 will be described. However, the heating member 68 is provided integrally with the writing device 64. Also good. In this case, the heating member 68 is provided at a position where heat can be applied between the display substrate 18 and the back substrate 20 of the display medium 62 in a state where the display medium 62 is mounted on the writing device 64. It only has to be.
Similarly, in the present embodiment, a case where the temperature detection unit 69 is configured integrally with the display medium 62 will be described. However, the temperature detection unit 69 is provided integrally with the writing device 64. It may be done.

In the hollow structure 90A, the first stimulus is the same as the hollow structure 26 described in the first embodiment, except that the hole diameter of the connection hole 26B is changed by the action of heat instead of the action of the electric field. Since it is a structure, detailed description is abbreviate | omitted.
That is, the hollow structure 90A provided in the display medium 62 of the present embodiment changes to an open state or a closed state by the action of heat as a first stimulus.

  The material, configuration, and manufacturing method that constitute such a hollow structure 90A are the same as those of the hollow structure 26 described in the first embodiment, except that the tubular body that constitutes the connection hole 26B. 27A (refer FIG. 4) is a different point.

  Specifically, the stimulus response material constituting the tubular body 27A that forms the connection hole 26B of the hollow structure 90A of the present embodiment is a material that responds by thermal stimulation, and this heat action A material that changes the hole diameter of the connecting hole 26B may be used.

  Here, the change in the hole diameter of the connecting hole 26B due to the action of heat is that the solubility in the solvent (dispersion medium) changes due to the heat acting on the material constituting the tubular body 27A constituting the connecting hole 26B. For example, if the solubility increases, the volume of the solvent (dispersion medium) permeates into the material and increases in volume, and if the solubility decreases, the solvent (dispersion medium) is discharged from the material. The volume decreases and becomes a closed state.

  In order to change the solubility of the solvent (dispersion medium) in the tubular body 27A and change the connection hole 26B to an open state or a closed state, heat applied between the display substrate 18 and the back substrate 20 is changed. The temperature and heating time vary depending on the material constituting the tubular body 27A, the solubility parameter of the solvent (dispersion medium), etc., but may be measured in advance when the display medium 12 is configured.

  Specific examples of such a stimulus-responsive material that changes by the action of heat include cross-linked N-alkyl-substituted (meth) acrylamides such as poly-N-isopropylacrylamide, N-alkyl-substituted (meth) acrylamide, and (meta ) Crosslinked products of copolymers of two or more components such as acrylic acid and its salts, or (meth) acrylamide or (meth) acrylic acid alkyl ester, crosslinked products of polyvinyl methyl ether, methyl cellulose, ethyl cellulose, hydroxypropyl cellulose, etc. Cross-linked products of alkyl-substituted cellulose derivatives, IPN bodies consisting of a cross-linked body of poly (meth) acrylamide and a cross-linked body of poly (meth) acrylic acid, semi-IPN bodies and partial neutralized bodies thereof (partially chlorinated acrylic acid units ) And poly (meth) acrylamide as the main component IPN body comprising a crosslinked body of the crosslinked poly (meth) acrylic acid copolymer, and the like semi-IPN bodies and their partial neutralization thereof. More preferably, a crosslinked product of poly N-alkyl-substituted alkylamide, an IPN product of a crosslinked product of poly (meth) acrylamide and a crosslinked product of poly (meth) acrylic acid, a semi-IPN product, and a partially neutralized product thereof. Can be mentioned. Etc.

  Among these, a N-alkyl-substituted (meth) acrylamide cross-linked product is preferably used for reasons of cost, handling, and stimulus responsiveness.

  As the solvent for the stimulus responsive material, a known solvent may be used as long as it has a function of causing a change in solubility of the stimulus responsive material within a use temperature range. Specifically, water, an organic solvent ( For example, alcohols such as methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, ethylene glycol, and propylene glycol; ketones such as acetone and methyl ethyl ketone; ethers; esters; etc., dimethylformamide, dimethylacetamide, dimethylsulfo Oxide, acetonitrile, ethylene carbonate, propylene carbonate, tetrahydrofuran, pyrrolidone derivatives), oils (for example, aliphatic, aromatic organic solvents, silicone oil), ionic liquids (for example, 1-ethyl-3-methylimidazole) Mubromide, 1-ethyl-3-methylimidazolium chloride, 1-ethyl-3-methylimidazolium lactate, 1-ethyl-3-methylimidazolium hexafluorophosphate, 1-ethyl-3-methylimidazolium bromide Tetrafluoroborate, 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, 1-butyl-3-methylimidazolium bromide, 1-butyl-3-methylimidazolium chloride, 1-butyl-3-hexafluorophosphate Methylimidazolium tetrafluoroborate, -1-butyl-3-methylimidazolium trifluoromethanesulfonate, -1-butyl-3-methylimidazolium lactate, 1-hexyl-3-methylimidazolium bromide, 1-hex 1-hexyl-3-methylimidazolium lactate, 1-hexyl-3-methylimidazolium hexafluorophosphate, 1-hexyl-3-methylimidazolium bromide tetrafluoroborate, 1-hexyl-3-methylimidazolium lactate -Ethyl-3-methylimidazolium trifluoromethanesulfonate, 1-octyl-3-methylimidazolium bromide, 1-octyl-3-methylimidazolium chloride, 1-octyl-3-methylimidazolium lactate, hexafluorophosphate- 1-octyl-3-methylimidazolium, 1-octyl-3-methylimidazolium bromide tetrafluoroborate, 1-octyl-3-methylimidazolium trifluoromethanesulfonate, 1-decyl-3-methyl Louis imidazolium bromide, 1-decyl-3-methylimidazolium chloride, 1-decyl-3-methylimidazolium lactate, 1-decyl-3-methylimidazolium hexafluorophosphate, 1-decyl-3-methylimidazole Lilium bromide tetrafluoroborate, 1-decyl-3-methylimidazolium trifluoromethanesulfonate, 1-dodecyl-3-methylimidazolium bromide, 1-dodecyl-3-methylimidazolium chloride, 1-dodecyl-3-methylimidazolium Lactate, 1-dodecyl-3-methylimidazolium hexafluorophosphate, 1-dodecyl-3-methylimidazolium bromide tetrafluoroborate, 1-dodecyl-3-methylimidazolium trifluoromethanesulfurate 1-ethyl-2,3-dimethylimidazolium bromide, 1-ethyl-2,3-dimethylimidazolium chloride, 1-ethyl-2,3-dimethylimidazolium lactate, hexafluorophosphate-1-ethyl- 2,3-dimethylimidazolium, 1-ethyl-2,3-dimethylimidazolium bromide tetrafluoroborate, 1-ethyl-2,3-dimethylimidazolium trifluoromethanesulfonate, 1-butyl-2,3-dimethylimidazolium Bromide, 1-butyl-2,3-dimethylimidazolium chloride, 1-butyl-2,3-dimethylimidazolium tetrafluoroborate hexafluorophosphate, -1-butyl-2,3-dimethylimidazolium trifluoromethanesulfonate , -1- Til-2,3-dimethylimidazolium lactate, 1-hexyl-2,3-dimethylimidazolium bromide, 1-hexyl-2,3-dimethylimidazolium chloride, 1-hexyl-2,3-dimethylimidazolium lactate, 1-hexyl-2,3-dimethylimidazolium hexafluorophosphate, 1-hexyl-2,3-dimethylimidazolium bromide tetrafluoroborate, 1-ethyl-2,3-dimethylimidazolium trifluoromethanesulfonate, 1- Octyl-2,3-dimethylimidazolium bromide, 1-octyl-2,3-dimethylimidazolium chloride, 1-octyl-2,3-dimethylimidazolium lactate, 1-octyl-2,3-hexafluorophosphate Dimethyl imidazole 1-octyl-2,3-dimethylimidazolium bromide tetrafluoroborate, 1-octyl-2,3-dimethylimidazolium trifluoromethanesulfonate, 1-decyl-2,3-dimethylimidazolium bromide, 1-decyl- 2,3-dimethylimidazolium chloride, 1-decyl-2,3-dimethylimidazolium lactate, 1-decyl-2,3-dimethylimidazolium hexafluorophosphate, 1-decyl-2,3-dimethylimidazolium Bromide tetrafluoroborate, 1-decyl-2,3-dimethylimidazolium trifluoromethanesulfonate, 1-dodecyl-2,3-dimethylimidazolium bromide, 1-dodecyl-2,3-dimethylimidazolium chloride, 1-dodecyl- 2 3-dimethylimidazolium lactate, 1-dodecyl-2,3-dimethylimidazolium hexafluorophosphate, 1-dodecyl-2,3-dimethylimidazolium bromide tetrafluoroborate, 1-dodecyl-2,3-dimethylimidazole Lithium trifluoromethanesulfonate, 1-ethylpyridinium bromide, 1-ethylpyridinium chloride, 1-ethylpyridinium lactate, 1-ethylpyridinium hexafluorophosphate, 1-ethylpyridinium tetrafluoroborate, 1-ethylpyridinium trifluoromethanesulfonate, 1 -Butylpyridinium bromide, 1-butylpyridinium chloride, 1-butylpyridinium lactate, 1-butylpyridinium hexafluorophosphate, 1-butylpyridinium tet Fluoroborate, 1-butylpyridinium trifluoromethanesulfonate, 1-hexylpyridinium bromide, 1-hexylpyridinium chloride, 1-hexylpyridinium lactate, hexafluorophosphate-1-hexylpyridinium, 1-hexylpyridinium tetrafluoroborate, 1-hexyl Pyridinium trifluoromethanesulfonate) and any mixtures thereof.

  Moreover, you may add surfactant etc. to the solution which melt | dissolved this irritation | stimulation response material in the said solvent as needed. By adding the surfactant, the effect of adjusting the temperature causing the solubility change can be obtained.

  The stimuli-responsive material that responds by the action of heat is produced in the same manner as the hollow structure 26 described in the first embodiment, except that the material is used to form the tubular body 27A that forms the connection hole 26B. In this way, the first space 26A having the same shape as the colloidal particle structure 29 (see FIG. 5), and the connecting hole 26B formed by the tubular body 27A whose pore diameter is changed by the action of heat as the first stimulus, A negative hollow structure 90 </ b> A having the following structure is manufactured.

  The manufacturing method of the hollow structure 90A is not limited to the above method, and any method can be used as long as the 26 can be manufactured with the hollow structure having the connection hole 26B and the first space 26A. It may be used.

Next, the display device 60 and the writing device 64 of the present embodiment will be described.
As described above, the display device 60 includes the display medium 62 and the writing device 64 for displaying an image on the display medium 62.

The writing device 64 includes a voltage application unit 14, a control unit 67, and an image information acquisition unit 17.
The voltage application unit 14 is connected to the control unit 67 so as to be able to send and receive signals, and is connected to the display electrode 24 and the back electrode 30 so as to be able to apply a voltage. Each of the heating member 68 and the temperature detection unit 69 is connected to the control unit 67 so as to be able to exchange signals.

  The image information acquisition unit 17 acquires image information indicating an image to be displayed on the display medium 62 from outside the display device 60 and the writing device 64.

  The control unit 67 controls the voltage applied from the voltage application unit 14 to the display medium 62 according to the image information acquired by the image information acquisition unit 17. The control unit 67 is constituted by a microcomputer including a CPU 67A, a ROM 67B, a RAM 67C, and a hard disk (not shown). The CPU 67A displays an image on the display medium 62 in accordance with a program stored in the ROM 67B or a hard disk (not shown).

The display medium 62 may be provided so as to be detachable from the writing device 64 or may be fixed while being electrically connected to the writing device 64.
By providing the display medium 62 so as to be detachable from the writing device 64, the display medium 62 can be exchanged, and an image can be displayed on a plurality of display media 62 using one writing device 64. .

  Below, the process performed by CPU67A of the control part 67 of the display apparatus 60 provided with the display medium 62 in this Embodiment is demonstrated.

  The CPU 67A of the control unit 67 reads the program shown by the processing routine shown in FIG. 16 from the ROM 67B or the hard disk in the control unit 67, thereby executing the process shown in FIG.

  In the present embodiment, in order to simplify the description, the image information acquisition unit 17 acquires information indicating the color of the image displayed in one specific cell of the display medium 62 as the image information. A case where a color based on the image information is displayed in one corresponding cell of the display medium 62 will be described.

  In the processing routine shown in FIG. 16, as the first particles 36 enclosed in the display medium 12, the first particles 36 having a characteristic of moving between the substrates by an electric field formed between the substrates are used. Explain the case.

  In this embodiment, it is assumed that the electrophoresis voltage information, the closing temperature information, and the opening temperature information are stored in the ROM 67B in advance.

The electrophoretic voltage information is stored in advance corresponding to the color information indicating the color displayed on the display medium 62.
The electrophoretic voltage information refers to the voltage value of the voltage for moving the first particles 36 in the display medium 62 from either the display substrate 18 or the back substrate 20 to the other substrate side, the voltage This is information indicating application time (hereinafter referred to as electrophoresis time), polarity, and the like, and is determined by the configuration of the first particles 36, the configuration of the display medium 62, and the like.

  The closed temperature information is the temperature of heat applied between the display substrate 18 and the back substrate 20 necessary for changing the connection hole 26B of the hollow structure 90A from the open state to the closed state, and the hollow structure body. This is information indicating the duration time (hereinafter referred to as the closing time) of the temperature required until the diameter of the connecting hole 26B of 90A becomes narrower and becomes the closed state from the open state. This closing temperature information is determined by the solubility parameter of the material constituting the connection hole 26B, other characteristics, the configuration of the display medium 12, and the like.

  The opening temperature information is the temperature of heat applied between the display substrate 18 and the back substrate 20 necessary for changing the connection hole 26B of the hollow structure 90A from the closed state to the open state, and the hollow structure body. This is information indicating a duration time (hereinafter referred to as an opening time) of the temperature necessary for the diameter of the connecting hole 26B of 90A to expand and change from the closed state to the open state. This opening temperature information is determined by the solubility parameter of the material constituting the connection hole 26B, other characteristics, the configuration of the display medium 12, and the like.

  The temperature of heat applied between the display substrate 18 and the back substrate 20 required to change the connection hole 26B of the hollow structure 90A from the closed state to the open state, and the connection hole 26B of the hollow structure 26 The temperature of the heat applied between the display substrate 18 and the back substrate 20 necessary for changing the aperture from the open state to the closed state is different from each other, preferably 10 degrees or more, preferably 50 More preferably, the difference is more than one degree.

  If these temperatures differ by 50 degrees or more, an effect is obtained that memory performance can be obtained in many living environments.

In the present embodiment, in order to change the connecting hole 26B of the hollow structure 90A from the closed state to the open state, a temperature exceeding the first temperature is applied between the display substrate 18 and the back substrate 20. In order to change the connection hole 26B of the hollow structure 26 from the open state to the closed state, the display substrate 18 and the back substrate 20 are less than the second temperature lower than the first temperature. A description will be given on the assumption that a temperature needs to be applied.
The opening temperature is determined in advance as a temperature exceeding the first temperature, and the closing temperature is determined as a temperature lower than the second temperature.

  Furthermore, it is preferable that this closing temperature is normal temperature (10 degreeC-40 degreeC) from a viewpoint of use environment.

  What is necessary is just to select suitably the stimulus responsive material which comprises the connection hole 26B so that these temperature may be satisfy | filled.

  The electrophoretic voltage information, the opening temperature information, and the aggregation temperature information may be measured for each display medium 62 in advance and stored in the ROM 67B in advance.

In the CPU 67A of the control unit 67, the processing routine shown in FIG.
In step 300, it is determined whether or not the image information acquisition unit 17 has acquired image information. If the determination is negative, the routine ends. If the determination is affirmative, the process proceeds to step 302.

  In step 302, the opening temperature information of the connection hole 26B is read from the ROM 67B.

  In the next step 304, the color information included in the image information acquired in step 300 is read.

  In the next step 306, the electrophoretic voltage information corresponding to the color information read in step 304 is read from the ROM 67B, and in the next step 308, the opening temperature information read in step 302 is output to the heating member 68. The heating member 68 that has received the opening temperature information starts to generate heat based on the temperature corresponding to the opening temperature information and the opening time.

  In the next step 310, it is determined whether or not the temperature in the display medium 62 is the same as the temperature information included in the opening temperature information read in step 302, and the negative determination is repeated until affirmative.

  The determination in step 310 is performed by determining whether or not the temperature information input from the temperature detection unit 69 is the same as the temperature information included in the opening temperature information read in step 302. Note that “whether or not they are the same” means that the temperature information input from the temperature detector 69 is within an error range of several percent with respect to the temperature information included in the opening temperature information read in step 302 above. As long as they match with each other. The value of several percent may be determined in advance according to the characteristics of the hollow structure 90A, the arrangement conditions of the display medium 62, and the like.

  In the next step 311, it is determined whether or not the opening time included in the opening temperature information has elapsed since the determination in step 310 is affirmed, and the negative determination is repeated until the determination is affirmed. move on.

  By heating the heating member 68 by performing the processing of Steps 308 to 311, the region between the display substrate 18 and the back substrate 20 is heated to a temperature corresponding to the opening temperature information read in Step 302. In the environment where the temperature is applied to the hollow structure 90A, the heating is continued until the connection hole 26B is changed from the closed state to the open state.

  For this reason, the connection hole 26 </ b> B of the hollow structure 90 </ b> A existing between the display substrate 18 and the back substrate 20 is brought into an open state by the processing of the above step 308 to step 311.

In the next step 312, the electrophoretic voltage information read in step 306 is output to the voltage application unit 14.
The voltage application unit 14 that has received the electrophoretic voltage information continues the electrophoretic time included in the electrophoretic voltage information with the voltage of the voltage value included in the received electrophoretic voltage information in the polarity included in the electrophoretic voltage information. Then, voltage application to be applied to the display electrode 24 and the back electrode 30 is started.

  In the next step 314, it is determined whether or not the voltage migration time included in the electrophoretic voltage information output to the voltage application unit 14 in step 312 has elapsed since the end of the processing in step 312, and a negative determination is made until affirmative. If the determination is affirmative again, the process proceeds to step 316.

  By the processing of step 312 to step 314, for example, a voltage for moving to the display substrate 18 side is applied to the display electrode 24 and the back electrode 30, and the first particles 36 are on the display substrate 18 side or the back substrate 20 side. To. Here, since the connection hole 26B of the hollow structure 90A is in an open state by the processing of Steps 308 to 311 described above, the first particles 36 that have reached the display substrate 18 side where the hollow structure 90A is provided. Passes through the connecting hole 26B of the hollow structure 90A and reaches the first space 26A.

  In step 316, the closing temperature information is read from the ROM 67 </ b> B, and in the next step 318, the read closing temperature information is output to the heating member 68.

  The heating member 68 that has received the closing temperature information starts a process of continuously heating the temperature information included in the received closing temperature information to the temperature for the aggregation time.

  In the next step 320, the negative determination is repeated until the temperature of the display medium 62 matches the temperature of the temperature information included in the closing temperature information read in step 316. If the determination is affirmative, the process proceeds to step 321. The determination in step 320 can be made by determining whether the temperature information input from the temperature detection unit 69 matches the temperature information included in the closing temperature information read in step 318. Note that the determination of whether or not they coincide does not necessarily indicate complete coincidence. For example, it may be coincident within a range of several percent of the temperature of the closing temperature information depending on the characteristics of the hollow structure 90A. What is necessary is just to define for every characteristic of 90 A of hollow structures.

  In the next step 321, after the closing temperature information is output to the heating member 68 in the above step 318, the negative determination is repeated until the closing time included in the closing temperature information read in the above step 316 elapses. Go to step 322.

  By the processing from step 318 to step 321, the connection hole 26 </ b> B of the hollow structure 90 </ b> A changes from the open state to the closed state.

  In the next step 321, after outputting a signal indicating voltage application stop to the voltage application unit 14, this routine is terminated. The voltage application unit 14 that has received the signal indicating the voltage application stop stops the voltage application to the display electrode 24 and the back electrode 30.

  By performing the processing of step 300 to step 322 shown in FIG. 16, for example, the first particle 36 is present on the back substrate 20 side before the processing routine is executed, and When the image information acquired in the process of step 300 includes color information indicating the color of the first particle 36, the hollow structure 90A is obtained by performing the process of steps 300 to 311. The connection hole 26 </ b> B is an opening that allows the passage of the first particles 36 from the closed state (see FIG. 17A), which is a state in which the passage of the first particles 36 is difficult due to the expansion of the holes. The state changes (see FIG. 17B).

  Further, by performing the processing of step 312 to step 314, the first particles 36 existing on the back substrate 20 side are electrophoresed in the dispersion medium 42 (see FIG. 17C). It reaches the first space 26A through the connecting hole 26B in the open state of the hollow structure 90A of the display medium 62 (see FIG. 17D).

  Here, by further executing the processing of step 316 to step 321, the connection hole 26 </ b> B of the hollow structure 90 </ b> A is in an open state (a state in which the first particles 36 can pass due to the narrowing of the hole). The state changes from the state shown in FIG. 17D to the closed state (see FIG. 17E) in which it is difficult for the first particles 36 to pass through.

  Here, as shown in FIG. 17E, the first particles 36 have reached the first space 26A. For this reason, when the connection hole 26B changes from the open state to the closed state due to temperature stimulation, it becomes difficult for the first particles 36 to pass through the connection hole 26B, and the first particle 26A that has reached the first space 26A is reached. The particles 36 are held in the first space 26A. Even if the heating by the heating member 68 is stopped in this state, the closed state of the connection hole 26B is maintained, so that the first particles 36 that have reached the first space 26A are retained in the first space 26A. The

As described above, the movement of the first particles 36 between the first spaces 26A of the hollow structure 90A through the connection holes 26B and the movement from the inside of the hollow structure 90A to the outside are suppressed. .
Therefore, the density change of the display medium 62 is suppressed.

On the other hand, when the image information acquired in the processing of step 300 includes color information indicating the color of the intermediate layer 38 of the display medium 62, the processing of steps 302 to 311 is performed. Thereby, for example, the connection hole 26B of the hollow structure 90A provided on the display substrate 18 side changes from the closed state shown in FIG. 17E to the open state shown in FIG. And after this connection hole 26B changes to an open state, the 1st particle | grains 36 currently hold | maintained in the 1st space 26A of 90 A of hollow structures are hollow structure via the connection hole 26B in an open state. Electrophoresis starts to the outside of the body 90A (see FIG. 17C), and further reaches the back substrate 20 side through the hole of the intermediate layer 38 (see FIG. 17B). And then. Further, the connecting hole 26B of the hollow structure 90A changes from the open state (see FIG. 17B) to the closed state (see FIG. 17A). Thereby, when visually recognized from the display substrate 18 side, the color of the intermediate layer 38 is visually recognized, and multicolor display becomes possible.
Further, since the connection hole 26B of the hollow structure 90A provided on the display substrate 18 side is closed after the first particles 36 move to the back substrate 20 side, the connection holes 26B move to the back substrate 20 side. The density change of the display medium 62 due to the color of the first particle 36 group is suppressed.

(Fourth embodiment)
In the third embodiment, the hollow structure 90A in which the connection hole 26B is changed to the open state or the closed state by the action of heat is used as the first stimulus, and the display substrate 18 is used as the first particle 36. The case where particles having the characteristic of moving between the substrates by the electric field formed between the rear substrate 20 and the substrate has been described.
In the present embodiment, as with the third embodiment, the hollow structure 90A in which the connection hole 26B is changed to an open state or a closed state by the action of heat is used as the hollow structure 90A as in the third embodiment. However, the first particle 36 has a characteristic that it moves between the substrates by an electric field formed between the display substrate 18 and the rear substrate 20, and the second stimulus between the display substrate 18 and the rear substrate 20. A case will be described in which the first particles 36B having a characteristic of being aggregated or dispersed by the action of heat applied therebetween are used.

  As shown in FIG. 18, the display device 60 </ b> A according to the present embodiment is configured to include a display medium 62 </ b> A and a writing device 64.

  The writing device 64 includes a voltage application unit 14, an image information acquisition unit 17, and a control unit 71. The voltage application unit 14 and the image information acquisition unit 17 are connected to the control unit 71 so as to be able to exchange signals.

  The display medium 62A corresponds to the display medium of the present invention, the display device 60A corresponds to the display device of the present invention, and the writing device 64 corresponds to the writing device of the present invention. The voltage application unit 14 corresponds to voltage application means of the display device and writing device of the present invention.

  The display medium 62A includes the display substrate 18, the back substrate 20, the gap member 34, the dispersion medium 42, the hollow structure 90A, the intermediate layer 38, and the first particles 36B.

  In addition, a heating member 68 and a temperature detection unit 69 are provided on the surface of the back substrate 20 of the display medium 62 </ b> A opposite to the surface facing the display substrate 18.

  Since the display medium 62A, the writing device 64, and the display device 60A of the present embodiment have the same configuration as that of the third embodiment, the same reference numerals are given to the same parts, and detailed description will be given. Omitted.

  The first particles 36 </ b> B have a property of being aggregated or dispersed by the action of heat as a second stimulus, in addition to a property of moving between the substrates by an electric field formed between the display substrate 18 and the back substrate 20. Particles. The first particles 36 </ b> B move in the dispersion medium 42 when a voltage within a predetermined migration voltage range and a voltage exceeding the migration voltage range is applied between the display substrate 18 and the back substrate 20. Aggregates or disperses by the action of heat as a stimulus of 2.

  The aggregation and dispersion of the first particles 36B in the dispersion medium 42 due to the action of heat is caused by the material constituting at least the surface (surface) of the first particles 36B in contact with the dispersion medium 42 being less than a predetermined temperature by the action of heat. This is caused by being dissolved in the dispersion medium 42 at a low temperature and precipitated on the surface of the first particles 36B at a high temperature equal to or higher than the predetermined temperature.

  That is, by configuring the material constituting at least the surface of the first particle 36B with a predetermined temperature, that is, a material that dissolves or precipitates in the dispersion medium 42 with the phase transition temperature as a boundary, in a temperature environment equal to or higher than the predetermined temperature. The first particles 36B that aggregate and disperse in a temperature environment below a predetermined temperature are adjusted.

  In order to cause dispersion and aggregation of the first particles 36B, the temperature of the heat applied between the display substrate 18 and the back substrate 20 and the continuous heating time are determined by the phase of the material constituting the surface of the first particles 36B. What is necessary is just to predetermine according to transition temperature, the kind of dispersion medium 42, etc.

  Examples of the first particles 36 </ b> B having the characteristics of electrophoresis in the dispersion medium 42 by the electric field and the characteristics of aggregation and dispersion by the thermal stimulation as the second stimulus include, for example, predetermined in the dispersion medium 42. By modifying the polymer chain having phase point transfer in the temperature range on the surface of the first particle 36 adjusted as a particle moving between the substrates by the action of the electric field described in the first embodiment, The first particles 36B are brought into a dispersed state or agglomerated state by thermal stimulation as described above.

  As this specific surface treatment, for example, a functional group or a polymer having desired characteristics in the first particle 36 by introducing an active group by a coupling agent or the like, or by surface activation by plasma discharge, corona discharge, X-ray irradiation, or the like. A chain may be introduced or encapsulated with a material having desired characteristics.

  For example, surface activation by plasma discharge, corona discharge, X-ray irradiation, etc. can be applied to almost all materials, and the characteristics of aggregation and dispersion by thermal stimulation by exposing the activated surface in the presence of a temperature sensitive monomer This first particle 36B can be obtained. In order to give the electrophoretic property in the dispersion medium 42 by an electric field, the temperature-sensitive monomer and the electrolyte monomer may coexist or may be modified stepwise, or the charged group may be modified in advance. Also good.

Next, the display device 60A and the writing device 64A of the present embodiment will be described.
As described above, the display device 60A includes the display medium 62A and the writing device 64A for displaying an image on the display medium 62A.

The writing device 64 </ b> A includes the voltage application unit 14, the control unit 71, and the image information acquisition unit 17.
The voltage application unit 14 is connected to the control unit 71 so as to be able to send and receive signals, and is connected to the display electrode 24 and the back electrode 30 so as to be able to apply a voltage. Each of the heating member 68 and the temperature detection unit 69 is connected to the control unit 71 so as to be able to exchange signals.

  The image information acquisition unit 17 acquires image information indicating an image to be displayed on the display medium 62A from outside the display device 60A and the writing device 64A.

  The control unit 71 controls the voltage applied from the voltage application unit 14 to the display medium 62A according to the image information acquired by the image information acquisition unit 17. The control unit 71 includes a microcomputer including a CPU 71A, a ROM 71B, a RAM 71C, and a hard disk (not shown). The CPU 71A displays an image on the display medium 62A according to a program stored in the ROM 71B or a hard disk (not shown).

The display medium 62A may be provided so as to be detachable from the writing device 64, or may be fixed while being electrically connected to the writing device 64A.
By providing the display medium 62A so as to be detachable from the writing device 64A, the display medium 62A can be replaced, and an image can be displayed on a plurality of display media 62A using one writing device 64A. .

  Below, the process performed by CPU71A of the control part 71 of 60 A of display apparatuses provided with the display medium 62A in this Embodiment is demonstrated.

  The CPU 71A of the control unit 71 executes the processing shown in FIG. 19 by reading the program shown by the processing routine shown in FIG. 19 from the ROM 71B or the hard disk in the control unit 71.

  In the present embodiment, in order to simplify the description, the image information acquisition unit 17 acquires information indicating the color of an image displayed in one specific cell of the display medium 62A as the image information. A case where a color based on the image information is displayed in one corresponding cell of the display medium 62A will be described.

  Further, in the present embodiment, it is assumed that the electrophoresis voltage information, the closing temperature information, the opening temperature information, the dispersion temperature information, and the aggregation temperature information are stored in the ROM 67B in advance.

The electrophoretic voltage information is stored in advance corresponding to the color information indicating the color displayed on the display medium 62A.
The electrophoretic voltage information refers to the voltage value and voltage of the voltage for moving the first particles 36B in the display medium 62A from either the display substrate 18 or the back substrate 20 to the other substrate side. This is information indicating the application time (hereinafter referred to as electrophoresis time), polarity, and the like, and is determined by the configuration of the first particle 36B, the configuration of the display medium 62A, and the like.

  Further, since the closing temperature information and the opening temperature information have been described in the above embodiment, detailed description thereof is omitted.

  The dispersion temperature information is a temperature necessary for bringing the first particles 36B into a dispersed state in the dispersion medium 42, and the first particles 36B shift from the dispersed state to the agglomerated state and become the intended agglomerated state. Information indicating the continuous holding time (hereinafter, referred to as dispersion time) of the temperature required until the phase, the phase transition temperature of the material constituting the surface of the first particle 36B, the type of the dispersion medium 42, the first It depends on the other characteristics of the particles 36B and the configuration of the display medium 62A.

  Further, the aggregation temperature information is a temperature necessary for bringing the first particles 36B into the aggregated state in the dispersion medium 42, and the first aggregated particles 36B are shifted from the dispersed state to the aggregated state and the target aggregated state is obtained. Information indicating a continuous holding time (hereinafter referred to as agglomeration time) of the temperature required until the phase is reached, and the phase transition temperature of the material constituting the surface of the first particle 36B, the type of the dispersion medium 42, It is determined by other characteristics of the first particles 36B, the configuration of the display medium 62A, and the like.

  The temperature of heat applied between the display substrate 18 and the back substrate 20 required to change the connection hole 26B of the hollow structure 90A from the closed state to the open state, and the connection hole 26B of the hollow structure 26 The temperature of heat applied between the display substrate 18 and the back substrate 20 required to change the temperature from the open state to the closed state, temperature information included in the aggregation temperature information, and temperature information included in the dispersion temperature information Are different from each other, preferably 10 degrees or more, more preferably 50 degrees or more.

  If these temperatures differ by 50 degrees or more, an effect is obtained that memory performance can be obtained in many living environments.

  In the present embodiment, the stimuli-responsive material constituting the connection hole 26B and the first particles 36B so that the temperature increases in the order of the closing temperature, the particle aggregation temperature, the opening temperature, the particle dispersion temperature, and the closing temperature. In the following description, it is assumed that the material constituting the material is appropriately selected. Further, the closing temperature will be described as being within a normal temperature range (10 ° C. or higher and 40 ° C. or lower).

  The electrophoretic voltage information, the opening temperature information, the closing temperature information, the aggregation temperature information, and the dispersion temperature information may be measured in advance for each display medium 62A and stored in the ROM 71B in advance.

In the CPU 71A of the control unit 71, the processing routine shown in FIG.
In step 400, it is determined whether or not the image information acquisition unit 17 has acquired image information. If the determination is negative, this routine is terminated. If the determination is affirmative, the process proceeds to step 402.

  In step 402, the opening temperature information of the connection hole 26B is read from the ROM 71B.

  In the next step 404, the color information included in the image information acquired in step 400 is read.

  In the next step 406, electrophoretic voltage information corresponding to the color information read in step 404 is read from the ROM 71B.

  In the next step 408, the particle dispersion temperature information is read from the ROM 71B.

  In the next step 410, the opening temperature information read in step 402 is output to the heating member 68. The heating member 68 that has received the opening temperature information starts to generate heat based on the temperature corresponding to the opening temperature information and the opening time.

  In the next step 412, it is determined whether or not the temperature in the display medium 62 is the same as the temperature information included in the opening temperature information read in step 402, and the negative determination is repeated until affirmative.

  The determination in step 412 is made by determining whether the temperature information input from the temperature detection unit 69 is the same as the temperature information included in the opening temperature information read in step 402. Note that “whether or not they are the same” means that the temperature information input from the temperature detector 69 is within an error range of several percent with respect to the temperature information included in the opening temperature information read in step 402 above. As long as they match with each other. The value of several percent may be determined in advance according to the characteristics of the hollow structure 90A, the arrangement condition of the display medium 62, and the like.

  By heating the heating member 68 by performing the processes of Steps 410 to 412, the region between the display substrate 18 and the back substrate 20 is heated to a temperature corresponding to the opening temperature information read in Step 402. Thus, the connecting hole 26B is changed from the closed state to the opened state.

  For this reason, the connection hole 26 </ b> B of the hollow structure 90 </ b> A existing between the display substrate 18 and the back substrate 20 is brought into an open state by the processing of Steps 410 to 412.

  In the next step 414, the particle dispersion temperature information read in step 408 is output to the heating member 68. The heating member 68 that has received the particle dispersion temperature information starts to generate heat to the temperature based on the temperature corresponding to the particle dispersion temperature information and the dispersion time.

  In the next step 414, it is determined whether or not the temperature in the display medium 62A is the same as the temperature of the particle dispersion temperature information read in step 408, and the negative determination is repeated until affirmative.

  The determination in step 414 is determined by determining whether the temperature information input from the temperature detection unit 69 is the same as the particle dispersion temperature information read in step 408. Note that “whether or not they are the same” means that the temperature information input from the temperature detector 69 is within an error range of several percent with respect to the temperature information included in the particle dispersion information read in step 408. As long as they match with each other. The value of several percent may be determined in advance according to the characteristics of the first particles 36B, the arrangement conditions of the display medium 62A, and the like.

  The first particles 36 </ b> B existing between the display substrate 18 and the back substrate 20 are dispersed in the dispersion medium 42 by the processing of the above steps 414 to 416.

In the next step 418, the electrophoretic voltage information read in step 406 is output to the voltage application unit 14.
The voltage application unit 14 that has received the electrophoretic voltage information continues the electrophoretic time included in the electrophoretic voltage information with the voltage of the voltage value included in the received electrophoretic voltage information in the polarity included in the electrophoretic voltage information. Then, voltage application to be applied to the display electrode 24 and the back electrode 30 is started.

  In the next step 420, it is determined whether or not the voltage migration time included in the electrophoretic voltage information output to the voltage applying unit 14 in step 418 has elapsed since the end of the process in step 418, and a negative determination is made until affirmative. If the determination is affirmative again, the process proceeds to step 422.

  By the processing of Step 418 to Step 420, for example, a voltage for moving to the display substrate 18 side is applied to the display electrode 24 and the back electrode 30, and the first particles 36B are displayed on the display substrate 18 side or the back substrate 20 side. To. Here, since the connection hole 26B of the hollow structure 90A is in an open state by the processing of Steps 410 to 412, the first particles 36B that have reached the display substrate 18 side where the hollow structure 90A is provided. Passes through the connecting hole 26B of the hollow structure 90A and reaches the first space 26A.

  In step 422, the particle aggregation temperature information is read from the ROM 71B, and in the next step 424, the read particle aggregation temperature information is output to the heating member 68.

  The heating member 68 that has received the particle aggregation temperature information starts a process of continuously heating the temperature information included in the received particle aggregation temperature information to the temperature for the aggregation time.

  In the next step 426, negative determination is repeated until the temperature of the display medium 62A matches the temperature of the aggregation temperature information read in step 422. If the determination is affirmative, the process proceeds to step 428. The determination in step 426 can be made by determining whether or not the temperature information input from the temperature detection unit 69 matches the temperature of the aggregation temperature information read in step 422. Note that the determination of whether or not they coincide does not necessarily indicate complete coincidence. For example, if the coincidence is within a range of several percent of the temperature of the aggregation temperature information due to the characteristics of the first particles 36B, for example. What is necessary is just to determine for every characteristic of the 1st particle | grains 36B.

  The first particles 36B are in an aggregated state by the processing of step 424 to step 426.

  In the next step 428, the closing temperature information is read from the ROM 71 </ b> B, and in the next step 430, the read closing temperature information is output to the heating member 68.

  The heating member 68 that has received the closing temperature information starts a process of continuously heating the temperature information included in the received closing temperature information to the temperature for the closing time.

  In the next step 432, negative determination is repeated until the temperature of the display medium 62 matches the temperature of the temperature information included in the closing temperature information read in step 428. If the determination is affirmative, the process proceeds to step 434. The determination in step 432 can be made by determining whether the temperature information input from the temperature detection unit 69 matches the temperature of the temperature information included in the closing temperature information read in step 428. Note that the determination of whether or not they coincide does not necessarily indicate complete coincidence. For example, the coincidence may be within a range of several percent of the temperature of the closing temperature information depending on the characteristics of the hollow structure 90A. What is necessary is just to define for every characteristic of 90 A of hollow structures.

  By the processing from step 428 to step 432, the connection hole 26B of the hollow structure 90A changes from the open state to the closed state.

  In the next step 434, a signal indicating that the voltage application is stopped is output to the voltage application unit 14, and then this routine is terminated. The voltage application unit 14 that has received the signal indicating the voltage application stop stops the voltage application to the display electrode 24 and the back electrode 30.

  By performing the processing of step 400 to step 434 shown in FIG. 19, for example, the first particle 36B is present on the back substrate 20 side before the processing routine is executed, and When the image information acquired by the process of step 400 includes color information indicating the color of the first particle 36B, the hollow structure 90A is obtained by performing the processes of step 400 to step 412. The connection hole 26B of the first opening 36B is an opening that allows passage of the first particles 36B from a closed state (see FIG. 20A), in which the passage of the first particles 36B is difficult due to the expansion of the holes. The state changes (see FIG. 20B).

  Furthermore, the first particles 36 </ b> B are in a dispersed state by executing the processing of step 414 to step 416.

  Then, by executing the processing of step 418 to step 420, the first particles 36B existing on the back substrate 20 side are electrophoresed in the dispersion medium 42 to form the hollow structure 90A of the display medium 62A. The first space 26A is reached through the connecting hole 26B in the open state (see FIG. 20C).

  Here, the processing of Steps 422 to 426 is further performed, whereby the first particles 36B are in an aggregated state. Here, since the first particles 36B have reached the first space 26A by the processing of the above steps 418 to 420, the first particles 36B have aggregated in the first space 26A. It will be in a state (refer to Drawing 20 (D)).

  Furthermore, by performing the processing of step 428 to step 432, the connection hole 26B of the hollow structure 90A is in an open state (see FIG. 20D) in which the first particles 36B can pass. Then, the first particle 36B changes to a closed state (see FIG. 20E), which is a difficult state for the passage of the first particle 36B.

As shown in FIG. 20E, the first particles 36B have reached the first space 26A. For this reason, it becomes difficult for the first particles 36B to pass through the connection hole 26B due to the change of the connection hole 26B from the open state to the closed state due to temperature stimulation, and the first particle 26B reaches the first space 26A. The particles 36B are held in the first space 26A. Even if the heating by the heating member 68 is stopped in this state, the closed state of the connecting hole 26B is maintained.
Furthermore, since the first particles 36B held in the first space 26A are in an aggregated state in the first space 26A, compared to a case where the first particles 36B are not in an aggregated state, Furthermore, movement to the outside of the hollow structure 90A through the connection hole 26B is suppressed.

  In this way, the movement of the first particles 36B between the first spaces 26A of the hollow structure 90A via the connection holes 26B and the movement from the inside of the hollow structure 90A to the outside are suppressed. . Therefore, the density change of the display medium 62A is suppressed.

  On the other hand, when the image information acquired in the process of step 400 includes color information indicating the color of the intermediate layer 38 of the display medium 62A, the processes of step 400 to step 412 are performed. Accordingly, for example, the connection hole 26B of the hollow structure 90A provided on the display substrate 18 side changes from the closed state shown in FIG. 20E to the open state shown in FIG. Further, by executing the processing of step 414 to step 420, the first particles 36B are released from the aggregated state to be in a dispersed state, and the first particles 36B in the dispersed state are It starts to move from the 18 side to the back substrate 20 side (see FIG. 20C).

  Further, the first particles 36B reach the back substrate 20 side through the holes of the intermediate layer 38 (see FIG. 20B). Further, by executing the processing of step 422 to step 426, the first particles 36B that have reached the back substrate 20 side are aggregated on the back substrate 20 side. For this reason, since it becomes difficult for the first particles 36B in the aggregated state to pass through the holes of the intermediate layer 38, a change in the concentration of the display medium 62A is suppressed.

Furthermore, the processing of step 428 to step 432 changes the connection hole 26B of the hollow structure 90A from the open state (see FIG. 20B) to the closed state (see FIG. 20A). Thereby, when visually recognized from the display substrate 18 side, the color of the intermediate layer 38 is visually recognized, and multicolor display becomes possible.
Further, the connection hole 26B of the hollow structure 90A provided on the display substrate 18 side is closed after the first particles 36B move to the back substrate 20 side, and the first particles 36B are in an aggregated state. Therefore, the color of the first particles 36B that have moved to the back substrate 20 side is suppressed from being visually recognized from the display substrate 18 side, and the change in the density of the display medium 62A is suppressed.

(Fifth embodiment)
In the first embodiment and the second embodiment, the case where the connection hole 26B of the hollow structure 26 is changed to the open state or the closed state by the action of an electric field has been described as the first stimulus. . In the present embodiment, a case will be described in which the connection hole 26B of the hollow structure 26 changes to an open state or a closed state by the action of light as a first stimulus.

  Since the present embodiment has the same configuration as that of the above embodiment, the same portions are denoted by the same reference numerals and detailed description thereof is omitted.

  As shown in FIG. 21, the display device 70 according to the present embodiment includes a display medium 72 and a writing device 74. In the display device 70, the same components as those of the display device 10 described above are given the same numbers, and detailed description thereof is omitted.

  The writing device 74 includes a voltage application unit 14, an image information acquisition unit 17, and a control unit 77. The voltage application unit 14 and the image information acquisition unit 17 are connected to the control unit 77 so as to be able to exchange signals.

  The display medium 72 corresponds to the display medium of the present invention, the display device 70 corresponds to the display device of the present invention, and the writing device 74 corresponds to the writing device of the present invention. The voltage application unit 14 corresponds to voltage application means of the display device and writing device of the present invention.

  The display medium 72 includes a display substrate 18 that serves as an image display surface, a rear substrate 20 that faces the display substrate 18 with a gap, and holds the substrates at a predetermined interval, and also between the display substrate 18 and the rear substrate 20. The gap member 34 partitioned into a plurality of cells, the dispersion medium 42, the hollow structure 90B, the intermediate layer 38, and the first particles 36 enclosed in each cell are configured.

  Further, a light irradiation unit 78 is provided on the surface of the back substrate 20 of the display medium 72 opposite to the surface facing the display substrate 18.

The light irradiation unit 78 is a device for irradiating light between the display substrate 18 and the back substrate 20, and is connected to the control unit 77 so that signals can be exchanged.
The light irradiation unit 78 is a device capable of selectively irradiating a region between the display substrate 18 and the back substrate 20 with light in a specific wavelength region corresponding to the information based on information input from the control unit 77. Any configuration can be used.

  Although illustration is omitted, the display medium 72 may be provided with a light intensity measurement device for measuring the intensity of light emitted from the light irradiation unit 78. In this case, the light intensity measuring device may be connected to the control unit 77 so as to be able to exchange signals.

  In the present embodiment, the case where the light irradiation unit 78 is provided integrally with the display medium 72 will be described. However, the light irradiation unit 78 has a configuration provided integrally with the writing device 74. There may be. In this case, in a state where the display medium 72 is mounted on the writing device 74, the light irradiation unit 78 is at a position where light can be irradiated between the display substrate 18 and the back substrate 20 of the display medium 72. What is necessary is just to be provided.

  A plurality of first particles 36 are enclosed in the dispersion medium 42 of the display medium 72. Since the first particles 36 have been described in the first embodiment, description thereof is omitted.

The hollow structure 90B has a first space 26A and a connection hole 26B, as with the hollow structure 26 described in the first embodiment.
In the hollow structure 90B, the first stimulus is the hollow structure 26 described in the first embodiment except that the diameter of the connection hole 26B is changed by the action of light instead of the action of the electric field. Since it is the same structure, detailed description is abbreviate | omitted.
That is, the connection hole 26B of the hollow structure 90B provided in the display medium 62 of the present embodiment changes to an open state or a closed state by the action of light as a first stimulus.

  The material, configuration, and manufacturing method of the hollow structure 90B are the same as those of the hollow structure 26 described in the first embodiment, except that the tubular body that forms the connection hole 26B. 27A (refer FIG. 4) is a different point.

  Specifically, as a stimulus responsive material used to adjust the tubular body 27A forming the connection hole 26B of the hollow structure 90B, a material that responds to light stimulation, and is connected as a result of the action of light. A material that changes the hole diameter of the hole 26B may be used.

  Here, the change of the hole diameter of the connecting hole 26B due to the action of light is that optical isomerization reaction occurs when light in a specific wavelength region acts on the material constituting the tubular body 27A constituting the connecting hole 26B. This is caused by the change in polarity and the solubility of the solvent.

  In order to cause optical isomerization of the tubular body 27A and change the connection hole 26B to an open state or a closed state, the wavelength of light irradiated between the display substrate 18 and the back substrate 20 or the light The irradiation time varies depending on the material constituting the tubular body 27A, the solvent (dispersion medium), the temperature, and the like, but may be measured in advance when the display medium 72 is configured.

  As such a stimulus-responsive material that changes by the action of light, specifically, a crosslinked product of a polymer compound having a group that is ionically dissociated by light, such as a triarylmethane derivative or a spirobenzopyran derivative, is preferable. As such, a cross-linked product of a vinyl-substituted triarylmethane leuco derivative or a cross-linked product of another copolymer can be used. In addition, a crosslinked product of a polymer compound having a group that causes cis-trans isomerization by light, such as a compound having an azo group (particularly, an azobenzene structure) is preferable. Examples thereof include (meth) acryloyl group-containing azobenzene and (meth) cross-linked products, or cross-linked products of other copolymers. Etc.

  Among these, a crosslinked product of a copolymer of azobenzene and (meth) acrylamide is preferably used for reasons of cost, handling, stability, and developability to liquid crystal compounds.

  As the solvent for the stimulus responsive material, a known solvent may be used as long as it has a function of changing the solubility in the photoisomerization reaction of the stimulus responsive material, but water, an organic material, a mixture thereof, or the like is used. It is done. Specifically, as a solvent for the stimulus responsive material, water, an organic solvent (for example, alcohols such as methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, ethylene glycol, propylene glycol; ketones such as acetone and methyl ethyl ketone; In addition to ethers; esters; and the like, dimethylformamide, dimethylacetamide, dimethylsulfoxide, acetonitrile, ethylene carbonate, propylene carbonate, tetrahydrofuran, pyrrolidone derivatives), oils (for example, aliphatic, aromatic organic solvents, Silicone oil), ionic liquids (eg 1-ethyl-3-methylimidazolium bromide, 1-ethyl-3-methylimidazolium chloride, 1-ethyl-3-methylimidazolium lactate) 1-ethyl-3-methylimidazolium hexafluorophosphate, 1-ethyl-3-methylimidazolium bromide tetrafluoroborate, 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, 1-butyl-3-methylimidazole 1-butyl-3-methylimidazolium chloride, 1-butyl-3-methylimidazolium tetrafluoroborate hexafluorophosphate, 1-butyl-3-methylimidazolium trifluoromethanesulfonate, 1-butyl -3-methylimidazolium lactate, 1-hexyl-3-methylimidazolium bromide, 1-hexyl-3-methylimidazolium chloride, 1-hexyl-3-methylimidazolium lactate, hexafluoroline -1-hexyl-3-methylimidazolium, 1-hexyl-3-methylimidazolium bromide tetrafluoroborate, 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, 1-octyl-3-methylimidazolium bromide, 1 -Octyl-3-methylimidazolium chloride, 1-octyl-3-methylimidazolium lactate, 1-octyl-3-methylimidazolium hexafluorophosphate, 1-octyl-3-methylimidazolium bromide tetrafluoroborate, 1-octyl-3-methylimidazolium trifluoromethanesulfonate, 1-decyl-3-methylimidazolium bromide, 1-decyl-3-methylimidazolium chloride, 1-decyl-3-methylimidazolium Mulactate, 1-decyl-3-methylimidazolium hexafluorophosphate, 1-decyl-3-methylimidazolium bromide tetrafluoroborate, 1-decyl-3-methylimidazolium trifluoromethanesulfonate, 1-dodecyl-3- Methylimidazolium bromide, 1-dodecyl-3-methylimidazolium chloride, 1-dodecyl-3-methylimidazolium lactate, hexafluorophosphate-1-dodecyl-3-methylimidazolium, 1-dodecyl-3-methylimidazole Rium bromide tetrafluoroborate, 1-dodecyl-3-methylimidazolium trifluoromethanesulfonate, 1-ethyl-2,3-dimethylimidazolium bromide, 1-ethyl-2,3-dimethylimidazolium chloride Id, 1-ethyl-2,3-dimethylimidazolium lactate, 1-ethyl-2,3-dimethylimidazolium hexafluorophosphate, 1-ethyl-2,3-dimethylimidazolium bromide tetrafluoroborate, 1- Ethyl-2,3-dimethylimidazolium trifluoromethanesulfonate, 1-butyl-2,3-dimethylimidazolium bromide, 1-butyl-2,3-dimethylimidazolium chloride, hexafluorophosphate-1-butyl-2, 3-dimethylimidazolium tetrafluoroborate, -1-butyl-2,3-dimethylimidazolium trifluoromethanesulfonate, -1-butyl-2,3-dimethylimidazolium lactate, 1-hexyl-2,3-dimethylimidazolium Bromide, 1- Xyl-2,3-dimethylimidazolium chloride, 1-hexyl-2,3-dimethylimidazolium lactate, 1-hexyl-2,3-dimethylimidazolium hexafluorophosphate, 1-hexyl-2,3-dimethyl Imidazolium bromide tetrafluoroborate, 1-ethyl-2,3-dimethylimidazolium trifluoromethanesulfonate, 1-octyl-2,3-dimethylimidazolium bromide, 1-octyl-2,3-dimethylimidazolium chloride, 1- Octyl-2,3-dimethylimidazolium lactate, 1-octyl-2,3-dimethylimidazolium hexafluorophosphate, 1-octyl-2,3-dimethylimidazolium bromide tetrafluoroborate, 1-octyl-2, 3-jime Tyrimidazolium trifluoromethanesulfonate, 1-decyl-2,3-dimethylimidazolium bromide, 1-decyl-2,3-dimethylimidazolium chloride, 1-decyl-2,3-dimethylimidazolium lactate, hexafluorophosphate -1-decyl-2,3-dimethylimidazolium, 1-decyl-2,3-dimethylimidazolium bromide tetrafluoroborate, 1-decyl-2,3-dimethylimidazolium trifluoromethanesulfonate, 1-dodecyl-2, 3-dimethylimidazolium bromide, 1-dodecyl-2,3-dimethylimidazolium chloride, 1-dodecyl-2,3-dimethylimidazolium lactate, hexafluorophosphate-1-dodecyl-2,3-dimethylimidazolium, 1 Dodecyl-2,3-dimethylimidazolium bromide tetrafluoroborate, 1-dodecyl-2,3-dimethylimidazolium trifluoromethanesulfonate, 1-ethylpyridinium bromide, 1-ethylpyridinium chloride, 1-ethylpyridinium lactate, hexafluoroline Acid-1-ethylpyridinium, 1-ethylpyridinium tetrafluoroborate, 1-ethylpyridinium trifluoromethanesulfonate, 1-butylpyridinium bromide, 1-butylpyridinium chloride, 1-butylpyridinium lactate, hexafluorophosphoric acid-1-butylpyridinium 1-butylpyridinium tetrafluoroborate, 1-butylpyridinium trifluoromethanesulfonate, 1-hexylpyridinium bromide, 1- Hexyl pyridinium chloride, 1-hexyl pyridinium lactate, hexafluorophosphate 1-hexyl pyridinium, 1-hexyl pyridinium tetrafluoro borate, 1-hexyl pyridinium trifluoromethanesulfonate) or any mixture thereof.

  The stimuli-responsive material that responds by the action of light is produced in the same manner as the hollow structure 26 described in the first embodiment, except that it is used as a material that constitutes the tubular body 27A that constitutes the connection hole 26B. Thus, the first space 26A having the same shape as the colloidal particle structure 29 (see FIG. 5), and the connection hole 26B formed by the tubular body 27A whose pore diameter is changed by the action of light as a first stimulus, A negative hollow structure 90B having the following structure is produced.

  The manufacturing method of the hollow structure 90B is not limited to the above method, and any method can be used as long as the hollow structure 90B having the configuration in which the connection hole 26B and the first space 26A are provided can be manufactured. May be.

  Next, the display device 70 and the writing device 74 of the present embodiment will be described.

  As described above, the display device 70 includes the display medium 72 and the writing device 74 for displaying an image on the display medium 72.

The writing device 74 includes a voltage application unit 14, a control unit 77, and an image information acquisition unit 17.
The voltage application unit 14 is connected to the control unit 77 so as to be able to exchange signals, and is connected to the display electrode 24 and the back electrode 30 so as to be able to apply a voltage. The light irradiation unit 78 is connected to the control unit 77 so as to be able to send and receive signals.

  The image information acquisition unit 17 acquires image information indicating an image to be displayed on the display medium 72 from outside the display device 70 and the writing device 74.

  The control unit 77 controls the voltage applied from the voltage application unit 14 to the display medium 72 according to the image information acquired by the image information acquisition unit 17 and irradiates the display medium 72 with light from the light irradiation unit 78. Control. The control unit 77 includes a CPU 77A, a ROM 77B, a RAM 77C, and a microcomputer including a hard disk (not shown). The CPU 77A displays an image on the display medium 72 according to a program stored in the ROM 77B or a hard disk (not shown).

The display medium 72 may be provided so as to be detachable from the writing device 74, or may be fixed while being electrically connected to the writing device 74.
By providing the display medium 72 so as to be detachable from the writing device 74, the display medium 72 can be exchanged, and an image can be displayed on a plurality of display media 72 using one writing device 74. .

  Below, the process performed by CPU77A of the control part 77 of the display apparatus 70 provided with the display medium 72 in this Embodiment is demonstrated.

  The CPU 77A of the control unit 77 reads the program shown by the processing routine shown in FIG. 22 from the ROM 77B or the hard disk in the control unit 77, thereby executing the process shown in FIG.

  In the present embodiment, in order to simplify the description, the image information acquisition unit 17 acquires information indicating the color of the image displayed in one specific cell of the display medium 72 as the image information. A case where a color based on the image information is displayed in one corresponding cell of the display medium 72 will be described.

  In the present embodiment, it is assumed that the electrophoresis voltage information is stored in the ROM 77B in advance.

The electrophoretic voltage information is stored in advance corresponding to the color information indicating the color displayed on the display medium 72.
The electrophoretic voltage information refers to the voltage value of the voltage for moving the first particles 36 in the display medium 72 from either the display substrate 18 or the back substrate 20 to the other substrate side, the voltage This is information indicating the application time (hereinafter referred to as electrophoresis time), polarity, and the like, and is determined by the above-described migration voltage range of the first particles 36 and the configuration of the display medium 72.

  The electrophoretic voltage information of the first particles 36 may be measured in advance for each display medium 72 and stored in the ROM 77B in advance.

  In this embodiment, it is assumed that aperture light information and closing light information are stored in the ROM 77B in advance.

  The aperture light information indicates a wavelength region (aperture wavelength region) of light necessary for expanding the diameter of the connection hole 26B of the hollow structure 90B and changing the connection hole 26B from the closed state to the open state. This is information indicating information and the irradiation time of light in the aperture wavelength region.

  The closed light information is a wavelength region (closed wavelength region) of light necessary for narrowing the diameter of the connection hole 26B of the hollow structure 90B and changing the connection hole 26B from the open state to the closed state. And information indicating the irradiation time of light in the closed wavelength region.

  The closed wavelength region and the aperture wavelength region are different from each other, and a material having such characteristics may be selected as the stimulus-responsive material. Specifically, a material having a group that is ionically dissociated by light, such as a triarylmethane derivative or a spirobenzopyran derivative, as a stimuli-responsive material, for example, a cross-linked product of a vinyl-substituted triarylmethane leuco derivative, or other common materials Examples include crosslinked polymers. Further, a material having a group that causes cis-trans isomerization by light, such as a compound having an azo group (particularly an azobenzene structure), such as a (meth) acryloyl group-containing azobenzene and a (meth) crosslinked product, or other Examples include a crosslinked product of a copolymer.

  The closing light information and the opening light information are determined by the characteristics of the material constituting the tubular body 27A forming the connection hole 26B, the type of the dispersion medium 42, the configuration of the display medium 72, and the like.

  The opening light information and the closing light information may be measured in advance for each display medium 72 and stored in the ROM 77B in advance.

  Below, the process performed by CPU77A of the control part 77 of the display apparatus 70 provided with the display medium 72 in this Embodiment is demonstrated.

In CPU 77A of control unit 77, the processing routine shown in FIG.
In step 500, it is determined whether or not the image information acquisition unit 17 has acquired image information. If the determination is negative, this routine is terminated. If the determination is affirmative, the process proceeds to step 502.

  In step 502, the opening light information of the connection hole 26B is read from the ROM 67B.

  In the next step 504, the color information included in the image information acquired in step 500 is read.

  In the next step 506, electrophoretic voltage information corresponding to the color information read in step 504 is read from the ROM 77B.

  In the next step 508, the light irradiation instruction signal including the aperture light information read in step 502 is output to the light irradiation unit 78. The light irradiation unit 78 that has received the light irradiation instruction signal, based on the wavelength region corresponding to the dispersion wavelength region information indicating the wavelength region of the light included in the aperture light information, and the continuous irradiation time information, Irradiation between the display substrate 18 and the back substrate 20 is started.

  In the next step 510, after the light irradiation instruction signal is output to the light irradiation unit 78 in step 508, the aperture light irradiation time included in the aperture light information of the light irradiation instruction signal output in step 508 elapses. If the negative determination is repeated and the determination is affirmative, the routine proceeds to step 512.

  By the processing from step 508 to step 510, the connection hole 26B of the hollow structure 90B changes from the closed state to the open state.

  In the next step 512, the electrophoretic voltage information read in step 506 is output to the voltage application unit 14, and in the next step 514, the electrophoresis output to the voltage application unit 14 in step 512 from the end of the processing in step 512. It is determined whether or not the electrophoresis time included in the voltage information has elapsed, and the negative determination is repeated until it is affirmed.

  The voltage application unit 14 that has received the electrophoretic voltage information starts applying the voltage of the electrophoretic voltage value included in the received electrophoretic voltage information between the display electrode 24 and the back electrode 30.

  For example, when a voltage for moving to the display substrate 18 side is applied to the display electrode 24 and the back electrode 30 by the processing of step 512 to step 514, the first particles that are dispersed in the dispersion medium 42. 36, the first particles 36 reach the display substrate 18 side and reach the first space 26A of the hollow structure 90B.

In step 516, the closing light information is read from the ROM 77 </ b> B, and in the next step 518, the read closing light information is output to the light irradiation unit 78.
The light irradiation unit 78 that has received the closed light information starts to irradiate light between the display substrate 18 and the back substrate 20 with light in the closed wavelength region of the received closed light information.

  In the next step 520, after the closing light information is output to the light irradiation unit 78 in the process of step 518, the light irradiation duration indicated by the closing light information output to the light irradiation unit 78 in step 520 elapses. If the negative determination is repeated until the determination is affirmative, the routine proceeds to step 522.

  By executing the processing of step 518 to step 520, the connection hole 26B of the hollow structure 90B changes from the open state to the closed state.

  Next, after outputting a signal indicating the stop of voltage application to the voltage application unit 14 by the process of step 522, after outputting a signal indicating the stop of light irradiation to the light irradiation unit 78 by the process of step 524, this routine is executed. finish.

  By executing the processing of step 522 and the processing of step 524, the voltage application by the voltage application unit 14 is stopped and the light irradiation by the light irradiation unit 78 is stopped.

  By performing the processing of step 500 to step 524 shown in FIG. 22, for example, before the processing routine is executed, the first particles 36 are present on the back substrate 20 side, and When the image information acquired in the process of step 500 includes color information indicating the color of the first particles 36, the hollow structure 90B is obtained by performing the process of steps 500 to 510. The connection hole 26 </ b> B is an opening that allows the passage of the first particles 36 from the closed state (see FIG. 23A), which is a state in which the passage of the first particles 36 is difficult due to the expansion of the holes. The state changes (see FIG. 23B).

  Furthermore, the first particles 36 existing on the back substrate 20 side are electrophoresed in the dispersion medium 42 by executing the processing of the above steps 512 to 514 (see FIG. 23C). It reaches the first space 26A through the connecting hole 26B in the open state of the hollow structure 90B of the display medium 72 (see FIG. 23D).

  Here, by further executing the processing of step 516 to step 520, the connection hole 26 </ b> B of the hollow structure 90 </ b> B is in an open state (a state in which the first particles 36 can pass due to the narrowing of the hole). The state changes from the state shown in FIG. 23D to the closed state (see FIG. 23E), which is a state in which the first particles 36 are difficult to pass.

  Here, as shown in FIG. 23E, the first particles 36 have reached the first space 26A. For this reason, when the connection hole 26B changes from the open state to the closed state by light stimulation, it becomes difficult for the first particles 36 to pass through the connection hole 26B, and the first particle 36 is held in the first space 26A. It becomes. Even if the light irradiation by the light irradiation unit 78 is stopped in this state, the closed state of the connection hole 26B is maintained, so the first particles 36 that have reached the first space 26A are in the first space 26A. Retained.

In this way, the movement of the first particles 36 between the first spaces 26A of the hollow structure 90B via the connection holes 26B and the movement from the inside of the hollow structure 90B to the outside are suppressed. .
Therefore, the density change of the display medium 72 is suppressed.

  On the other hand, when the image information acquired in the process of step 500 includes color information indicating the color of the intermediate layer 38 of the display medium 72, the processes of steps 502 to 510 are performed. Accordingly, for example, the connection hole 26B of the hollow structure 90B provided on the display substrate 18 side changes from the closed state shown in FIG. 23E to the open state shown in FIG. And after this connection hole 26B changes to an open state, the 1st particle | grains 36 currently hold | maintained in the 1st space 26A of the hollow structure 90B are hollow structure via the connection hole 26B in an open state. Electrophoresis starts to the outside of the body 90B (see FIG. 23C), and further reaches the back substrate 20 side through the hole of the intermediate layer 38 (see FIG. 23B). And then. Further, the connection hole 26B of the hollow structure 90B changes from the open state (see FIG. 23B) to the closed state (see FIG. 23A). Thereby, when visually recognized from the display substrate 18 side, the color of the intermediate layer 38 is visually recognized, and multicolor display becomes possible.

  Further, since the connection hole 26B of the hollow structure 90B provided on the display substrate 18 side is closed after the first particles 36 move to the back substrate 20 side, the connection holes 26B move to the back substrate 20 side. The density change of the display medium 72 due to the color of the first particle 36 group is suppressed.

(Sixth embodiment)
In the fifth embodiment, the hollow structure 90B in which the connection hole 26B changes to an open state or a closed state by the action of light is used as the first stimulus, and the display substrate 18 is used as the first particle 36. The case where the particles having the property of moving between the substrates by the electric field formed between the rear substrate 20 and the substrate has been described.
In the present embodiment, as with the fifth embodiment, as for the hollow structure 90B, the hollow structure 90B in which the connection hole 26B changes to an open state or a closed state by the action of light is used as the first stimulus. However, the first particle 36 has a characteristic that it moves between the substrates by an electric field formed between the display substrate 18 and the rear substrate 20, and the second stimulus between the display substrate 18 and the rear substrate 20. A case will be described in which the first particles 36C having a characteristic of being aggregated or dispersed by the action of light irradiated therebetween are used.

  As shown in FIG. 24, the display device 70A according to the present embodiment includes a display medium 72A and a writing device 74A.

  The writing device 74 </ b> A includes a voltage application unit 14, an image information acquisition unit 17, and a control unit 79. The voltage application unit 14 and the image information acquisition unit 17 are connected to the control unit 79 so as to exchange signals.

  The display medium 72A corresponds to the display medium of the present invention, the display device 70A corresponds to the display device of the present invention, and the writing device 74A corresponds to the writing device of the present invention. The voltage application unit 14 corresponds to voltage application means of the display device and writing device of the present invention.

  The display medium 72A includes the display substrate 18, the back substrate 20, the gap member 34, the dispersion medium 42, the hollow structure 90B, the intermediate layer 38, and the first particles 36C.

  In addition, a light irradiation unit 78 is provided on the surface of the back substrate 20 of the display medium 72 </ b> A opposite to the surface facing the display substrate 18.

  Note that the display medium 72A, the writing device 74A, and the display device 70A of the present embodiment have the same configuration as that of the fourth embodiment, and therefore, the same parts are denoted by the same reference numerals and detailed description thereof will be given. Omitted.

  The first particles 36 </ b> C further have a property of aggregating or dispersing by the action of light as a second stimulus, in addition to the property of moving between the substrates by the electric field formed between the display substrate 18 and the back substrate 20. Particles. The first particles 36 </ b> C move in the dispersion medium 42 when a voltage within a predetermined migration voltage range or exceeds the migration voltage range is applied between the display substrate 18 and the back substrate 20. Aggregate or disperse by the action of light as a stimulus of 2.

  Specifically, the first particles 36C aggregate when irradiated with light in a predetermined wavelength region (hereinafter referred to as an aggregation wavelength region), and a wavelength region outside the aggregation wavelength region (hereinafter referred to as a dispersion wavelength region). The light is dispersed in the dispersion medium 42.

  The aggregation and dispersion in the dispersion medium 42 due to the action of light of the first particles 36C is caused by the fact that the material constituting at least the surface (surface) in contact with the dispersion medium 42 of the first particles 36C is light in a specific wavelength region. It is generated by dissolving in the dispersion medium 42 by the action and depositing on the surface of the first particle 36C by the action of light in a wavelength region different from the wavelength region.

  That is, the wavelength of the light to be irradiated is adjusted by forming the material constituting at least the surface of the first particle 36C with a material that dissolves or precipitates in the dispersion medium 42 in accordance with the wavelength region of the light to be irradiated. Thus, the first particles 36C to be aggregated or dispersed are adjusted.

  In order to cause dispersion and aggregation of the first particles 36C, the wavelength region of light applied between the display substrate 18 and the back substrate 20 and the irradiation time of light in the wavelength region are determined by the surface of the first particle 36C. May be determined in advance according to the characteristics of the material constituting the material, the type of the dispersion medium 42, and the like.

  As the first particles 36C having the characteristics of electrophoresis in the dispersion medium 42 by this electric field and the characteristics of aggregation and dispersion by light stimulation, for example, by the action of the electric field explained in the first embodiment. The surface of the particles prepared as particles moving between the substrates is further modified with a material whose solubility is changed by irradiation with light, so that the first particles 36C become dispersed or aggregated by the light stimulation as described above. That's fine.

  As this specific surface treatment, the first particles 36 described in the first embodiment are treated by surface activation such as introduction of an active group by a coupling agent or the like, plasma discharge, corona discharge, X-ray irradiation, or the like. A functional group or a polymer chain having desired characteristics may be introduced into the first particles, or may be encapsulated with a material having desired characteristics.

  Specifically, photochromic active materials such as azobenzenes, spiropyrans, spirooxazines, diarylethenes, fulgides, and chromenes may be used.

  The first particles 36C can be produced by emulsion polymerization, suspension polymerization, membrane emulsion polymerization, force-free polymerization, seed polymerization, core / shell polymerization, plasma spray method, rolling granulation. Extrusion granulation method, compression granulation method, melt granulation method, spray drying granulation method, fluidized bed granulation method, crushing granulation method, stirring granulation method, coating granulation method, liquid phase granulation method, It is produced by vacuum freeze granulation.

  In addition, when using the 1st particle | grains 36C aggregated or disperse | distributed by the effect | action of light, the dispersion medium 42 is selected according to the material which forms the 1st particle | grains 36C, and the 1st particle | grains 36C are formed by light irradiation. A liquid having a characteristic that the solubility greatly changes before and after the photochromic rearrangement is used, and it is preferably a non-electrolyte liquid in order to obtain a potential gradient in the system from the dispersion medium 42 mentioned in the first embodiment.

  Next, the display device 70A and the writing device 74A according to the present embodiment will be described.

  As described above, the display device 70A includes the display medium 72A and the writing device 74A for displaying an image on the display medium 72A.

The writing device 74 </ b> A includes a voltage application unit 14, a control unit 79, and an image information acquisition unit 17.
The voltage application unit 14 is connected to the control unit 79 so as to be able to send and receive signals, and is connected to the display electrode 24 and the back electrode 30 so as to be able to apply a voltage. The light irradiation unit 78 is connected to the control unit 79 so as to be able to send and receive signals.

  The image information acquisition unit 17 acquires image information indicating an image to be displayed on the display medium 72A from outside the display device 70A and the writing device 74A.

  The control unit 79 controls the voltage applied from the voltage application unit 14 to the display medium 72A according to the image information acquired by the image information acquisition unit 17, and irradiates light from the light irradiation unit 78 into the display medium 72A. Control. The control unit 79 includes a CPU 79A, ROM 79B, RAM 79C, and a microcomputer including a hard disk (not shown). The CPU 79A displays an image on the display medium 72A according to a program stored in the ROM 79B or a hard disk (not shown).

The display medium 72A may be provided so as to be detachable from the writing device 74A, or may be fixed while being electrically connected to the writing device 74A.
By providing the display medium 72A so as to be detachable from the writing device 74A, the display medium 72A can be exchanged, and an image can be displayed on the plurality of display media 72A using one writing device 74A. .

  Hereinafter, processing executed by the CPU 79A of the control unit 79 of the display device 70A provided with the display medium 72A in the present embodiment will be described.

  The CPU 79A of the control unit 79 executes the processing shown in FIG. 25 by reading the program shown by the processing routine shown in FIG. 25 from the ROM 79B or hard disk in the control unit 79.

  In the present embodiment, in order to simplify the description, the image information acquisition unit 17 acquires information indicating the color of the image displayed in one specific cell of the display medium 72A as the image information. A case will be described in which a color based on the image information is displayed in one corresponding cell of the display medium 72A.

  In the present embodiment, it is assumed that electrophoretic voltage information is stored in the ROM 79B in advance.

The electrophoretic voltage information is stored in advance corresponding to the color information indicating the color displayed on the display medium 72A.
The electrophoretic voltage information refers to the voltage value and voltage of the voltage for moving the first particles 36C in the display medium 72A from either the display substrate 18 or the back substrate 20 to the other substrate side. This is information indicating the application time (hereinafter referred to as electrophoresis time), polarity, and the like, and is determined by the above-mentioned migration voltage range of the first particles 36C and the configuration of the display medium 72A.

  The electrophoretic voltage information of the first particles 36C may be measured in advance for each display medium 72A and stored in the ROM 79B in advance.

  Further, in the present embodiment, it is assumed that the aperture light information, the closing light information, the dispersed light information, and the aggregated light information are stored in the ROM 79B in advance.

  Since the opening light information and the closing light information have been described in the above embodiment, a detailed description thereof will be omitted.

  The dispersion light information is information indicating a wavelength region (dispersion wavelength region) of light necessary for dispersing the first particles 36C in the display medium 72A in the dispersion medium 42, and irradiation of light in the dispersion wavelength region. Information indicating time and the like.

  The aggregated light information includes information indicating a wavelength region (aggregated wavelength region) of light necessary for aggregating the first particles 36C in the display medium 72A in the dispersion medium 42, and the aggregated wavelength region. This is information indicating the light irradiation time and the like.

  These dispersed light information and aggregated light information are determined by the characteristics of the material constituting the surface of the first particle 36C, the type of the dispersion medium 42, the configuration of the display medium 72A, and the like.

  The opening light information, closing light information, aggregated light information, and dispersed light information may be measured in advance for each display medium 72A and stored in the ROM 79B in advance.

  In addition, information indicating the wavelength region included in each of the aperture light information, the closed light information, the aggregated light information, and the dispersed light information is different from each other. For this reason, the display medium 72A is a stimulus that constitutes the tubular body 27A that forms the connection hole 26B of the hollow structure 90B so that the aperture wavelength region, the closed wavelength region, the aggregation wavelength region, and the dispersion wavelength region are different from each other. What is necessary is just to select the response material and the material which comprises the 1st particle | grains 36C.

  Hereinafter, processing executed by the CPU 79A of the control unit 79 of the display device 70A provided with the display medium 72A in the present embodiment will be described.

In the CPU 79A of the control unit 79, the processing routine shown in FIG.
In step 600, it is determined whether or not the image information acquisition unit 17 has acquired image information. If the determination is negative, this routine is terminated. If the determination is affirmative, the process proceeds to step 602.

  In step 602, the opening light information of the connection hole 26B is read from the ROM 79B.

  In the next step 604, the color information included in the image information acquired in step 600 is read.

  In the next step 606, electrophoretic voltage information corresponding to the color information read in step 604 is read from the ROM 79B.

  In the next step 608, the dispersed light information is read from the ROM 79B.

  In the next step 610, a light irradiation instruction signal including the aperture light information read in step 602 is output to the light irradiation unit 78. The light irradiation unit 78 that has received the light irradiation instruction signal, based on the wavelength region corresponding to the dispersion wavelength region information indicating the wavelength region of the light included in the aperture light information, and the continuous irradiation time information, Irradiation between the display substrate 18 and the back substrate 20 is started.

  In the next step 612, after the light irradiation instruction signal is output to the light irradiation unit 78 in step 610, the aperture light irradiation time included in the aperture light information of the light irradiation instruction signal output in step 610 elapses. If the negative determination is repeated and the result is affirmative, the routine proceeds to step 612.

  By the processing from step 610 to step 612, the connection hole 26B of the hollow structure 90B changes from the closed state to the open state.

  In the next step 614, a light irradiation instruction signal including the dispersed light information read in step 608 is output to the light irradiation unit 78. The light irradiation unit 78 that has received the light irradiation instruction signal, based on the wavelength region corresponding to the dispersion wavelength region information indicating the wavelength region of the light included in the dispersion light information, and the continuous irradiation time information, Irradiation between the display substrate 18 and the back substrate 20 is started.

  In the next step 616, the light irradiation instruction signal is output to the light irradiation unit 78 in step 614, and then negated until the light irradiation time included in the dispersed light information of the light irradiation instruction signal output in step 614 elapses. If the determination is repeated and affirmed, the process proceeds to step 618.

  Through the processing of Step 614 to Step 616, the first particles 36C in the display medium 72A are dispersed in the dispersion medium 42.

  In the next step 618, the electrophoretic voltage information read in step 606 is output to the voltage application unit 14, and in the next step 620, the electrophoresis output to the voltage application unit 14 in step 618 after the processing in step 618 is completed. It is determined whether or not the electrophoresis time included in the voltage information has elapsed, and the negative determination is repeated until it is affirmed.

  The voltage application unit 14 that has received the electrophoretic voltage information starts applying the voltage of the electrophoretic voltage value included in the received electrophoretic voltage information between the display electrode 24 and the back electrode 30.

  For example, when a voltage for moving to the display substrate 18 side is applied to the display electrode 24 and the back electrode 30 by the processing of Step 618 to Step 620, the first particles that are dispersed in the dispersion medium 42. In 36C, the first particles 36C reach the display substrate 18 side and reach the first space 26A of the hollow structure 90B.

In the next step 622, the aggregated light information is read from the ROM 79 </ b> B, and in the next step 624, the read aggregated light information is output to the light irradiation unit 78.
The light irradiation unit 78 that has received the aggregated light information starts to irradiate between the display substrate 18 and the back substrate 20 with light in the wavelength region of the aggregated wavelength region of the received aggregated light information.

  In the next step 626, after the aggregated light information is output to the light irradiation unit 78 in the processing of step 624, the light irradiation duration indicated by the aggregated light information output to the light irradiation unit 78 in step 624 elapses. If the negative determination is repeated until the determination is affirmative, the routine proceeds to step 628.

In step 628, the closing light information is read from the ROM 79 </ b> B, and in the next step 630, the read closing light information is output to the light irradiation unit 78.
The light irradiation unit 78 that has received the closed light information starts to irradiate light between the display substrate 18 and the back substrate 20 with light in the closed wavelength region of the received closed light information.

  In the next step 632, the closing light information is output to the light irradiation unit 78 in the process of step 630, and then the light irradiation duration indicated by the closing light information output to the light irradiation unit 78 in step 630 elapses. If the negative determination is repeated until the determination is affirmative, the routine proceeds to step 634.

  By executing the processing of Step 628 to Step 632, the connection hole 26B of the hollow structure 90B changes from the open state to the closed state.

  Next, after outputting a signal indicating the stop of voltage application to the voltage application unit 14 by the process of step 634, and outputting a signal indicating the stop of light irradiation to the light irradiation unit 78 by the process of step 636, this routine is executed. finish.

  By executing the processing of step 634 and the processing of step 636, the voltage application by the voltage application unit 14 is stopped and the light irradiation by the light irradiation unit 78 is stopped.

  25, the first particles 36C are present on the back substrate 20 side, for example, before the processing routine is executed, and the processing of Step 600 to Step 636 shown in FIG. When the image information acquired by the process of step 600 includes color information indicating the color of the first particle 36C, the hollow structure 90B is performed by performing the processes of step 600 to step 612. The connection hole 26B of FIG. 6 is an opening that is in a state in which the first particles 36C can pass from the closed state (see FIG. 26A), in which the passage of the first particles 36C is difficult due to the expansion of the holes. The state changes (see FIG. 26B).

  Further, by performing the processing of step 614 to step 616, the first particles 36C existing on the back substrate 20 side are electrophoresed in the dispersion medium 42, so that the hollow structure 90B of the display medium 72A is obtained. The first space 26A is reached through the connecting hole 26B in the open state (see FIG. 26C).

  Here, by further executing the processing of step 622 to step 626, the first particles 36C change from the dispersed state to the aggregated state. Since the first particles 36C have reached the first space 26A by the processing of step 614 to step 616, the first particles 26C are aggregated in the first space 26A (FIG. 26D). reference).

  Furthermore, the processing of step 628 to step 632 is executed, so that the connection hole 26B of the hollow structure 90B is in an open state (FIG. 26 (FIG. 26 (D) in which the first particles 36C can pass through due to the narrowing of the hole). D)) to a closed state (see FIG. 26E), which is a difficult state for the passage of the first particles 36C.

Here, as shown in FIG. 26E, the first particles 36C have reached the first space 26A. For this reason, when the connection hole 26B changes from the open state to the closed state by light stimulation, it becomes difficult for the first particles 36C to pass through the connection hole 26B, and the first particle 36C is held in the first space 26A. It becomes. Even if the light irradiation by the light irradiation unit 78 is stopped in this state, the closed state of the connection hole 26B is maintained, so that the first particles 36C that have reached the first space 26A are in the first space 26A. Retained.
Furthermore, since the first particles 36C in the first space 26A are held in the first space 26A in an agglomerated state, the first particles 36C are further stabilized in the first state. Is held in the section 2A.

  Therefore, the density change of the display medium 72A is suppressed.

  On the other hand, when the image information acquired in the process of step 600 includes color information indicating the color of the intermediate layer 38 of the display medium 72A, the process of steps 600 to 612 is performed. Accordingly, for example, the connection hole 26B of the hollow structure 90B provided on the display substrate 18 side changes from the closed state shown in FIG. 26E to the open state shown in FIG. And after this connection hole 26B changes to an open state, after the 1st particle | grain 36C currently hold | maintained in the aggregated state in the 1st space 26A of the hollow structure 90B is made into the dispersed state, it will be in an open state Electrophoresis starts to the outside of the hollow structure 90B through a certain connection hole 26B (see FIG. 26C). Further, the first particles 36C reach the back substrate 20 side through the holes of the intermediate layer 38 (see FIG. 26B). And then. Furthermore, the first particles 36C that have reached the back substrate 20 side are aggregated by light irradiation, and the connection hole 26B of the hollow structure 90B is changed from the open state (see FIG. 26B) to the closed state (see FIG. 26). 26 (A)). Thereby, when visually recognized from the display substrate 18 side, the color of the intermediate layer 38 is visually recognized, and multicolor display becomes possible.

  Furthermore, since the connection hole 26B of the hollow structure 90B provided on the display substrate 18 side is closed after the first particles 36C move to the back substrate 20 side, the connection holes 26B move to the back substrate 20 side. The density change of the display medium 72A due to the color of the first particles 36C is suppressed.

  In the second embodiment, the fourth embodiment, and the sixth embodiment, when the first particles that are dispersed or aggregated by the second stimulus are used, the second particles are used. However, the present invention is not limited to such a form. However, the present invention is not limited to the above-described case where the type of stimulation is the same as the first type of stimulation for opening or closing the connection hole 26B of the hollow structure.

  That is, in the second embodiment, the fourth embodiment, and the sixth embodiment, when the first stimulus and the second stimulus are stimuli caused by an electric field, respectively, In the case of a stimulus and a case of a stimulus by light, each case has been described. For example, a hollow structure that is opened or closed by stimulation of an electric field, and an aggregated or dispersed state by stimulation of light It is good also as a display medium of the form which combined the 1st particle | grains 36 which become. In this case, a mechanism for applying each first stimulus and each second stimulus may be provided in the writing device.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, these examples do not limit the present invention. In this example, a display medium having the same structure as that shown in FIGS. 1, 15, and 24 was manufactured and evaluated.

Example 1
First, the display medium 62 shown in FIG. 15 was produced and evaluated. That is, in the first embodiment, a case where a hollow structure 90A in which the connection hole 26B changes to an open state or a closed state by thermal stimulation is provided in the display medium 62 as a hollow structure.

  First, the hollow structure 26 provided on the display substrate 18 side was produced by the following method.

As the display substrate 18 and the back substrate 20, an ITO glass substrate (5 cm × 10 cm, thickness 2 mm) was prepared one by one.
Next, the display substrate 18 is infiltrated into an ethanol suspension of monodispersed polystyrene particles (trade name: 5300A, manufactured by Duke Scientific) having a volume average primary particle size of 3.0 μm, and the substrate is formed using a dip coating method. A close-packed colloidal crystal layer made of polystyrene particles of about 15 μm was formed on the top (ITO surface of the display substrate 18).

  As stimuli responsive materials, 6 parts by weight of N-isopropylacrylamide, 0.01 parts by weight of cross-linking agent N, N′-methylenebisacrylamide (BIS) (manufactured by Wako Pure Chemical Industries, Ltd.), initiator acetaminophenone (Wa) 0.1 g of Koyo Pure Chemical Industries, Ltd.) was dissolved in 100 parts by weight of dioxane as a solvent and sufficiently substituted with nitrogen to obtain Solution F.

  The display substrate 18 on which the close-packed colloidal crystal layer is formed is placed on a weighing balance, and the adjusted solution F is dropped, whereby the solution F is placed in the particle gap of the close-packed colloidal crystal layer. And the solvent was evaporated until the added weight of the solution F became 1/6 by volatilizing the solvent at room temperature and normal pressure. Further, the close-packed colloidal crystal layer was irradiated with UV light to polymerize the monomer. Thus, the tubular body 27A that forms the connection hole 26B was adjusted.

  Further, by dropping a mixture of acrylic acid monomer (manufactured by Wako Pure Chemical Industries, Ltd.), BIS and acetaminophenone into the close-packed colloidal crystal layer, the mixture is introduced into the particle gap of the close-packed colloidal crystal layer. After being filled, a curing treatment was performed by UV light irradiation. A hollow structure having a thickness of 15 μm was formed on the display substrate 18 by immersing the obtained substrate in a sufficient amount of toluene and etching the polystyrene particles.

  When the obtained hollow structure (hollow structure 90A) was observed with a scanning electron microscope (SEM) in an environment at a temperature of 25 ° C., a void structure (corresponding to the first space 26A) having substantially the same shape as the polystyrene particles. It was observed that all the holes were connected through the connecting holes 26B. The hole constituting this void structure, that is, the long diameter of the first space 26A was 3 μm, and the hole diameter of the connecting hole 26B between the first spaces 26A constituting the void structure or the outside was 1 μm.

  Furthermore, when the temperature was increased at a rate of 1 ° C./second, it was observed that the connecting hole 26B was the largest in the opening state at the temperature of 20 ° C., and the closing state was the smallest in the connecting hole 26B at the temperature of 40 ° C. .

  The hole diameter of the connection hole 26B in the closed state was 0.3 μm, and the hole diameter of the connection hole 26B in the open state was 1.2 μm.

  Further, the connecting hole 26B formed a continuous space from the surface to the inside of the porous silica (hollow structure 90A). From the film thickness of this porous silica body (hollow structure 90A), this first space 26A is considered to be composed of about 8 layers (periods).

The following particles were used as the first particles 36 that move in the dispersion medium 42 in accordance with the electric field formed between the display substrate 18 and the back substrate 20 in Example 1.
Specifically, 8.0 g of a blue pigment (Dainippon Ink Chemical Co., Ltd .: Microencapsulated Pigment, MC Cyan) having a volume average primary particle size of 0.1 μm is added as a coloring material to 3 g of vinylferrocene, and these are stirred and mixed. The prepared acetonitrile / water mixed solution was prepared, and a pigment whose surface was modified with polyvinylferrocene by plasma polymerization was used as the first particles 36.

  The first particles 36 were negatively charged and the volume average primary particle size was 100 nm. A dispersion liquid in which the first particles 36 are dispersed in silicone oil as the dispersion medium 42 was prepared. The concentration of the first particles 36 in this dispersion was 4% by volume.

  Further, in Example 1, the hole diameter of the open connection hole 26B of the hollow structure 90A and the first space 26A of the hollow structure 90A are relative to the volume average primary particle size (100 nm) of the first particles 36. Were 5 times and 30 times, respectively.

  Next, as the intermediate layer 38, polymethyl methacrylate particles having a volume average primary particle size of 10 μm in which titanium oxide particles (volume average primary particle size of 0.2 μm) are dispersed at 60% by weight are used. Then, a dispersion liquid in which the polymethyl methacrylate particles were dispersed in ethanol at 5% by weight was applied to form a layer made of white particles (third particles 41) as the intermediate layer 38. The intermediate layer 38 had a thickness of 50 μm.

  Next, after providing a 100 μm resin spacer on the back substrate 20, the display substrate 18 on which the hollow structure 90A is formed is connected to the hollow structure 90A and the ITO side surface of the back substrate 20 through the resin spacer. And side-sealing was performed, leaving some openings. Further, the dispersion medium 42 was filled with a dispersion liquid in which the first particles 36 were dispersed by the decompression method from the opening, and then the opening was sealed to produce a display medium 62 for evaluation.

  When the display medium 62 manufactured in Example 1 was applied to the display electrode 24 and the back electrode 30 in a 20 ° C. environment for 5 seconds with a DC voltage of 5 V so that the display electrode 24 was a negative electrode, White color due to the intermediate layer 38 was displayed. When the reflection density at the time of white display was measured by X-rite 404 manufactured by X-rite, it was about 0.3.

  Next, from this white display state, under a 20 ° C. environment, when a DC voltage of 5 V was applied for 5 seconds so that the display electrode 24 became a positive electrode, the display medium 62 was blue. The concentration at this time was measured by X-rite 404 manufactured by X-rite, and was about 1.4. When the environment at 20 ° C. was further maintained, this blue color disappeared in about 1 minute.

Next, in the same manner as described above, when a DC voltage of 5 V was applied for 5 seconds in an environment of 20 ° C. so that the display electrode 24 became a positive electrode, the display medium 62 exhibited a blue color. Here, when the temperature is further raised to 40 ° C. and the display medium 62 is placed in the temperature environment of 40 ° C. and then the voltage application is canceled, the display medium 62 remains blue and 3 Even after being left in the environment for more than a month, no decolorization was observed.
Further, when each of the concentration immediately after placing the display medium 62 in an environment of 40 ° C. and the concentration after being left for 3 months was measured by X-rite 404 manufactured by X-rite,
Both were about 1.4, and suppression of concentration reduction was achieved.

  From the above, it has been confirmed that a decrease in density can be suppressed and a display medium 62 capable of multicolor display is obtained.

(Example 2)
In the first embodiment, the case where the hollow structure 90A in which the connection hole 26B is changed to the open state or the closed state by the thermal stimulation is provided in the display medium 62 has been described. In the second embodiment, the light stimulation is performed. The case where the hollow structure 90B (see FIG. 21) in which the connecting hole 26B changes to the open state or the closed state is provided in the display medium 62 will be described.

  In Example 2, the hollow structure 26 provided on the display substrate 18 side was produced by the following method.

As the display substrate 18 and the back substrate 20, an ITO glass substrate (5 cm × 10 cm, thickness 2 mm) was prepared one by one.
Next, the display substrate 18 is infiltrated into an ethanol suspension of monodispersed polystyrene particles (trade name: 5300A, manufactured by Duke Scientific) having a volume average primary particle size of 3.0 μm, and the substrate is formed using a dip coating method. A close-packed colloidal crystal layer made of polystyrene particles of about 15 μm was formed on the top (ITO surface of the display substrate 18).

  As stimulus-responsive materials, acrylamide 6 parts by weight, 4-acryloylaminoazobenzene 1 part by weight, cross-linking agent N, N′-methylenebisacrylamide (BIS) (manufactured by Wako Pure Chemical Industries, Ltd.) 0.01 part by weight, Initiator acetaminophenone (manufactured by Wako Pure Chemical Industries, Ltd.) (0.1 g) was dissolved in 100 parts by weight of dioxane as a solvent and sufficiently substituted with nitrogen to obtain Solution B.

  The display substrate 18 on which the close-packed colloidal crystal layer is formed is placed on a weighing balance, and the adjusted solution B is dropped, whereby the solution B is placed in the particle gap of the close-packed colloidal crystal layer. And the solvent was evaporated until the added weight of the solution B became 1/6 by volatilizing the solvent at room temperature and normal pressure. Further, the close-packed colloidal crystal layer was irradiated with UV light to polymerize the monomer. Thus, the tubular body 27A that forms the connection hole 26B was adjusted.

  Further, by dropping a mixture of acrylic acid monomer (manufactured by Wako Pure Chemical Industries, Ltd.), BIS and acetaminophenone into the close-packed colloidal crystal layer, the mixture is introduced into the particle gap of the close-packed colloidal crystal layer. After being filled, a curing treatment was performed by UV light irradiation. A hollow structure having a thickness of 15 μm was formed on the display substrate 18 by immersing the obtained substrate in a sufficient amount of toluene and etching the polystyrene particles.

  When the obtained hollow structure (hollow structure 90B) was observed with a scanning electron microscope (SEM), a porous body in which a void structure (corresponding to the first space 26A) having substantially the same shape as the polystyrene particles was formed. Thus, it was observed that all the holes were connected via the connecting hole 26B. The hole constituting this void structure, that is, the long diameter of the first space 26A was 3 μm, and the hole diameter of the connecting hole 26B between the first spaces 26A constituting the void structure or between the outside was 0.7 μm.

  When this hollow structure is irradiated with light and the wavelength of the irradiated light is changed, the connection hole 26B has the largest opening state when irradiated with light in the visible light region, and light in the wavelength region of 366 nm. It was observed that the connection hole 26B is in the closed state when the light is irradiated.

  The hole diameter of the connecting hole 26B in the closed state was 0.4 μm, and the hole diameter of the connecting hole 26B in the opened state was 1.1 μm.

  Further, the connecting hole 26B formed a continuous space from the surface to the inside of the porous silica (hollow structure 90B). From the film thickness of this porous silica (hollow structure 90B), it is considered that the first space 26A is composed of about 8 layers (periods).

  As the first particles 36 that move in the dispersion medium 42 according to the electric field formed between the display substrate 18 and the back substrate 20 in the second embodiment, the same first particles 36 as in the first embodiment. Was used.

  In Example 2, the diameter of the connection hole 26B in the open state of the hollow structure 90B and the first space 26A of the hollow structure 90B are relative to the volume average primary particle size (100 nm) of the first particles 36. Were 5 times and 30 times, respectively.

  Next, as the intermediate layer 38, polymethyl methacrylate particles having a volume average primary particle size of 10 μm in which titanium oxide particles (volume average primary particle size of 0.2 μm) are dispersed at 60% by weight are used. Then, a dispersion liquid in which the polymethyl methacrylate particles were dispersed in ethanol at 5% by weight was applied to form a layer made of white particles (third particles 41) as the intermediate layer 38. The intermediate layer 38 had a thickness of 50 μm.

  Next, after a 100 μm resin spacer is provided on the back substrate 20, the display substrate 18 on which the hollow structure 90A is formed is connected to the hollow structure 90B and the ITO side surface of the back substrate 20 through the resin spacer. And side-sealing was performed, leaving some openings. Further, after filling the dispersion medium 42 with the dispersion liquid in which the first particles 36 are dispersed by the decompression method from the opening, the opening is sealed to prepare a display medium 72 for evaluation (see FIG. 21).

  The display medium 72 manufactured in Example 2 was irradiated with light of 366 nm for 3 minutes using a high-pressure mercury lamp and a color filter, and then irradiated with the light of 366 nm. When a DC voltage of 5 V was applied to the electrode 30 for 5 seconds so that the display electrode 24 became a negative electrode, white color was displayed by the intermediate layer 38. When the reflection density at the time of white display was measured by X-rite 404 manufactured by X-rite, it was about 0.3.

  Next, from this white display state, the display medium 24 is irradiated with 366 nm light for 1 minute using a high-pressure mercury lamp and a color filter, and then the display electrode 24 is exposed to the 366 nm light. When a DC voltage of 5 V was applied for 5 seconds in such a manner, the display medium 62 exhibited a blue color. The concentration at this time was measured by X-rite 404 manufactured by X-rite, and was about 1.4. Further, when the irradiation of 366 nm light was maintained, this blue color disappeared in about 1 minute.

Next, in the same manner as described above, after irradiating the display medium 62 with light of 366 nm for 1 minute using a high pressure mercury lamp and a color filter, the display electrode 24 becomes a positive electrode in the state of irradiation with the light of 366 nm. When a DC voltage of 5 V was applied for 5 seconds, the display medium 62 was blue. Here, further, when the visible light region is irradiated to the display medium 62 using a visible light lamp and the voltage application is released 3 minutes after the light irradiation, the display medium 62 remains blue. There was no discoloration even when left in the environment for more than 3 months.
Further, after irradiating the display medium 62 with light in the visible light region, the concentration immediately after the voltage application is canceled one minute after the light irradiation, and after leaving the light in the visible light region for 3 months. As a result of measurement with X-rite 404 manufactured by X-rite, both of them were about 1.3.

  From the above, it has been confirmed that a decrease in density can be suppressed and a display medium 62 capable of multicolor display is obtained.

(Example 3)
In the first embodiment, the case where the hollow structure 90A in which the connection hole 26B is changed to the open state or the closed state by the thermal stimulation is provided in the display medium 62 has been described. However, in the third embodiment, the electrical stimulation is performed. The case where the hollow structure 26 (see FIG. 1) in which the connection hole 26B changes to the open state or the closed state is provided in the display medium 12 will be described.

  In Example 3, the hollow structure 26 provided on the display substrate 18 side was produced by the following method.

As the display substrate 18 and the back substrate 20, an ITO glass substrate (5 cm × 10 cm, thickness 2 mm) was prepared one by one.
Next, the display substrate 18 is infiltrated into an ethanol suspension of monodispersed polystyrene particles (trade name: 5300A, manufactured by Duke Scientific) having a volume average primary particle size of 3.0 μm, and the substrate is formed using a dip coating method. A close-packed colloidal crystal layer made of polystyrene particles of about 15 μm was formed on the top (ITO surface of the display substrate 18).

  As a stimulus-responsive material, N, N-dimethylaminoethyl acrylate methyl chloride and BIS were dissolved in 100 parts by weight of water as a solvent and sufficiently substituted with nitrogen to obtain Solution H.

  The display substrate 18 on which the close-packed colloidal crystal layer is formed is placed on a weighing balance, and the adjusted solution B is dropped, so that the solution H is introduced into the particle gap of the close-packed colloidal crystal layer. The solvent was evaporated until the added weight of the solution H became 1/6 by volatilizing the solvent at room temperature and normal pressure. Further, the close-packed colloidal crystal layer was irradiated with UV light to polymerize the monomer. Thus, the tubular body 27A that forms the connection hole 26B was adjusted.

  Further, by dropping a mixture of acrylic acid monomer (manufactured by Wako Pure Chemical Industries, Ltd.), BIS and acetaminophenone into the close-packed colloidal crystal layer, the mixture is introduced into the particle gap of the close-packed colloidal crystal layer. After being filled, a curing treatment was performed by UV light irradiation. A hollow structure having a thickness of 15 μm was formed on the display substrate 18 by immersing the obtained substrate in a sufficient amount of toluene and etching the polystyrene particles.

  When the obtained hollow structure (hollow structure 26) was observed with a scanning electron microscope (SEM), a porous body in which a void structure (corresponding to the first space 26A) having substantially the same shape as the polystyrene particles was formed. Thus, it was observed that all the holes were connected via the connecting hole 26B. The hole constituting this void structure, that is, the long diameter of the first space 26A was 3 μm, and the hole diameter of the connecting hole 26B between the first spaces 26A constituting the void structure or the outside was 1 μm.

  The connection hole 26B formed a continuous space from the surface to the inside of the porous silica (hollow structure 26). From the thickness of the porous silica (hollow structure 26), it is considered that the first space 26A is composed of about 8 layers (periods).

  As the first particles 36 that move in the dispersion medium 42 in accordance with the electric field formed between the display substrate 18 and the back substrate 20 in Example 3, the same first particles 36 as in Example 1 may be used. Was used.

  Next, as the intermediate layer 38, polymethyl methacrylate particles having a volume average primary particle size of 10 μm in which titanium oxide particles (volume average primary particle size of 0.2 μm) are dispersed at 60% by weight are used. Then, a dispersion liquid in which the polymethyl methacrylate particles were dispersed in ethanol at 5% by weight was applied to form a layer made of white particles (third particles 41) as the intermediate layer 38. The intermediate layer 38 had a thickness of 50 μm.

  Next, after providing a resin spacer of 100 μm on the back substrate 20, the display substrate 18 on which the hollow structure 90A is formed is connected to the surface of the hollow structure 26 and the back substrate 20 on the ITO side through the resin spacer. And side-sealing was performed, leaving some openings. Further, the dispersion medium 42 was filled with the dispersion liquid in which the first particles 36 were dispersed by the decompression method from the opening, and then the opening was sealed to produce a display medium 12 for evaluation (see FIG. 1).

  A voltage is applied to the display electrode 24 and the back electrode 30 between the display substrate 18 and the back substrate 20 of the display medium 12 manufactured in Example 3, and the voltage value of the applied voltage is changed. As a result, it was observed that when the voltage of + 3V was applied, the connection hole 26B was in the largest open state, and when the voltage of -3V was applied, the connection hole 26B was in the closed state.

  The hole diameter of the connecting hole 26B in the closed state was 0.3 μm, and the hole diameter of the connecting hole 26B in the opened state was 1.1 μm.

  Next, after applying a voltage of 3 V to the display electrode 24 and the back electrode 30 to the display medium 12 manufactured in Example 3 so that the display electrode 24 becomes a negative pole for 10 seconds, the display electrode 24 and the back electrode When a direct current voltage of 5 V was applied to 30 so that the display electrode 24 became a negative pole, white color was displayed by the intermediate layer 38. When the reflection density at the time of white display was measured by X-rite 404 manufactured by X-rite, it was about 0.3.

  Next, from this white display state, a 3V DC voltage was applied for 3 seconds so that the display electrode 24 became a positive electrode, and then a 5V DC voltage was further applied for 5 seconds. Presented. The concentration at this time was measured by X-rite 404 manufactured by X-rite, and was about 1.4. This blue color disappeared in about 1 minute.

  Next, in the same manner as described above, from the white display state, a direct current voltage of 3 V is applied for 3 seconds so that the display electrode 24 becomes a positive electrode, and the connecting hole 26B is opened. When the voltage was applied for 5 seconds, the display medium 62 was blue. Here, further, after applying the DC voltage of 3V for 5 seconds so that the display electrode 24 becomes a negative pole to close the connection hole 26B, the voltage application is released, and the display medium 62 exhibits blue. Even if it was left in the environment for more than 3 months, no decolorization was observed.

  Further, when the concentration immediately after the voltage application was canceled and the concentration after standing for 3 months were measured by X-rite 404 manufactured by X-rite, both were about 1.3, and the concentration decreased. Suppression was attempted.

  From the above, it was confirmed that the density reduction could be suppressed and the display medium 12 capable of multicolor display was obtained.

Example 4
In the first embodiment, the case where the hollow structure 90A in which the connection hole 26B is changed to the open state or the closed state by heat stimulation is provided in the display medium 62 has been described. In the fourth embodiment, the dispersion medium is used. A case will be described in which a hollow structure 26 (see FIG. 1) in which the connection hole 26B changes to an open state or a closed state due to a change in pH of 42 is provided in the display medium 12.

  In Example 4, the hollow structure 26 provided on the display substrate 18 side was produced by the following method.

As the display substrate 18 and the back substrate 20, an ITO glass substrate (5 cm × 10 cm, thickness 2 mm) was prepared one by one.
Next, the display substrate 18 is infiltrated into an ethanol suspension of monodispersed polystyrene particles (trade name: 5300A, manufactured by Duke Scientific) having a volume average primary particle size of 3.0 μm, and the substrate is formed using a dip coating method. A close-packed colloidal crystal layer made of polystyrene particles of about 15 μm was formed on the top (ITO surface of the display substrate 18).

  As stimuli-responsive materials, acrylic acid 6 parts by weight, cross-linking agent N, N′-methylenebisacrylamide (BIS) (manufactured by Wako Pure Chemical Industries, Ltd.) 0.01 part by weight, initiator acetaminophenone (Wako Pure Chemical) 0.1 g (manufactured by Kogyo Co., Ltd.) was dissolved in 100 parts by weight of dioxane as a solvent and sufficiently substituted with nitrogen to obtain Solution I.

  The display substrate 18 on which the close-packed colloidal crystal layer is formed is placed on a weighing balance, and the adjusted solution I is dropped, whereby the solution I is put into the particle gap of the close-packed colloidal crystal layer. Then, the solvent was evaporated until the added weight of the solution I became 1/6 by volatilizing the solvent at room temperature and under normal pressure. Further, the close-packed colloidal crystal layer was irradiated with UV light to polymerize the monomer. Thus, the tubular body 27A that forms the connection hole 26B was adjusted.

  Further, by dropping a mixture of acrylic acid monomer (manufactured by Wako Pure Chemical Industries, Ltd.), BIS and acetaminophenone into the close-packed colloidal crystal layer, the mixture is introduced into the particle gap of the close-packed colloidal crystal layer. After being filled, a curing treatment was performed by UV light irradiation. A hollow structure having a thickness of 15 μm was formed on the display substrate 18 by immersing the obtained substrate in a sufficient amount of toluene and etching the polystyrene particles.

  When the obtained hollow structure (hollow structure 26) was observed with a scanning electron microscope (SEM), a porous body in which a void structure (corresponding to the first space 26A) having substantially the same shape as the polystyrene particles was formed. Thus, it was observed that all the holes were connected via the connecting hole 26B. The hole constituting this void structure, that is, the long diameter of the first space 26A was 3 μm, and the hole diameter of the connecting hole 26B between the first spaces 26A constituting the void structure or the outside was 1 μm.

  The connection hole 26B formed a continuous space from the surface to the inside of the porous silica (hollow structure 26). From the thickness of the porous silica (hollow structure 26), it is considered that the first space 26A is composed of about 8 layers (periods).

As the first particles 36 that move in the dispersion medium 42 in accordance with the electric field formed between the display substrate 18 and the back substrate 20 in the fourth embodiment, the same first particles 36 as in the first embodiment. Was used.
In the fourth embodiment, water is used as the dispersion medium 42 for dispersing the first particles 36.

  Next, as the intermediate layer 38, polymethyl methacrylate particles having a volume average primary particle size of 10 μm in which titanium oxide particles (volume average primary particle size of 0.2 μm) are dispersed at 60% by weight are used. Then, a dispersion liquid in which the polymethyl methacrylate particles were dispersed in ethanol at 5% by weight was applied to form a layer made of white particles (third particles 41) as the intermediate layer 38. The intermediate layer 38 had a thickness of 50 μm.

  Next, after providing a resin spacer of 100 μm on the back substrate 20, the display substrate 18 on which the hollow structure 26 is formed is connected to the surface of the hollow structure 26 and the back substrate 20 on the ITO side through the resin spacer. And side-sealing was performed, leaving some openings. Further, the dispersion medium 42 was filled with the dispersion liquid in which the first particles 36 were dispersed by the decompression method from the opening, and then the opening was sealed to produce a display medium 12 for evaluation (see FIG. 1).

A voltage is applied to the display electrode 24 and the back electrode 30 between the display substrate 18 and the back substrate 20 of the display medium 12 manufactured in Example 4 so that the display electrode 24 becomes a negative electrode, and further applied. When the voltage value of the voltage to be changed is changed, 30 seconds have elapsed since the voltage of 3 V was applied so that the connecting hole 26B became the largest opening state in the state where no voltage was applied, and the display electrode 24 became a positive electrode. It has been observed that sometimes the connecting hole 26B is in a closed state.
This is because when a voltage of 3 V is applied, the pH of the dispersion medium 42 is lowered due to the electrolysis of water, and the reduction of the pH of the dispersion medium 42 causes the connection holes 26B to contract and close from the open state. It is thought that it changed to the state.

  The hole diameter of the connection hole 26B in the closed state was 0.3 μm, and the hole diameter of the connection hole 26B in the open state was 1 μm.

  Next, a DC voltage of 5 V is applied to the display medium 12 manufactured in Example 4 for 5 seconds so that the display electrode 24 and the back electrode 30 are negative, and the display electrode 24 and the back electrode 30 are negative. As a result, white color due to the intermediate layer 38 was displayed. When the reflection density at the time of white display was measured by X-rite 404 manufactured by X-rite, it was about 0.3.

  Next, from this white display state, when a DC voltage of 5 V was applied for 5 seconds so that the display electrode 24 became a positive electrode, the display medium 62 was blue. The concentration at this time was measured by X-rite 404 manufactured by X-rite, and was about 1.4. Further, when the voltage application was stopped, the blue color disappeared in about 1 minute.

  Next, in the same manner as described above, when a DC voltage of 5 V was applied for 5 seconds from the state of white display, the display medium 62 exhibited blue. Here, further, after applying the DC voltage of 3V for 30 seconds so that the display electrode 24 becomes a positive pole to close the connection hole 26B, the voltage application is released, and the display medium 62 exhibits blue. Even if it was left in the environment for more than 3 months, no decolorization was observed.

  Further, when the concentration immediately after the voltage application was canceled and the concentration after standing for 3 months were measured by X-rite 404 manufactured by X-rite, both were about 1.3, and the concentration decreased. Suppression was attempted.

  From the above, it was confirmed that the density reduction could be suppressed and the display medium 12 capable of multicolor display was obtained.

(Comparative Example 1)
A display medium was produced and evaluated in the same manner as in Example 1 except that the following hollow structure was used as the hollow structure.

  In this comparative example 1, a hollow structure provided on the display substrate 18 side was produced by the following method.

As the display substrate 18 and the back substrate 20, an ITO glass substrate (5 cm × 10 cm, thickness 2 mm) was prepared one by one.
Next, the display substrate 18 is infiltrated into an ethanol suspension of monodispersed polystyrene particles (trade name: 5300A, manufactured by Duke Scientific) having a volume average primary particle size of 3.0 μm, and the substrate is formed using a dip coating method. A close-packed colloidal crystal layer made of polystyrene particles of about 15 μm was formed on the top (ITO surface of the display substrate 18).

Using this close-packed colloidal crystal layer as a template, a SiO ₂ particle suspension aqueous solution (volume average primary particle size of SiO ₂ particles 6 nm, concentration 10% by weight, trade name: Cataloid. Catalyst Chemical Industry Co., Ltd.) is dip coated. By filling the particle gap of the structure by the above method and further heating at 500 ° C. for 1 hour, the polystyrene particles are decomposed to disappear the colloidal crystal structure, and the silica porous body having a thickness of about 15 μm (negative structure) Body).

When the obtained porous silica (hollow structure) was observed with a scanning electron microscope (SEM), it was a porous body in which a void structure (corresponding to the first space 26A) having substantially the same shape as the polystyrene particles was formed. It was observed that all the holes were connected via the connecting hole 26B. The long diameter of the holes constituting the void structure, that is, the first space 26A, was 3 μm, and the long diameter of the connecting holes 26B between the first spaces 26A constituting the void structure or between the outsides was 500 nm.
Further, the connecting hole 26B formed a continuous space from the surface to the inside of the porous silica (hollow structure). From the film thickness of this porous silica body (hollow structure), this first space 26A is considered to be composed of about 8 layers (periods).

  When the display medium manufactured in Comparative Example 1 was applied to the display electrode 24 and the back electrode 30 with a DC voltage of 5 V for 5 seconds in an environment of 20 ° C. so that the display electrode 24 became a negative pole, A white color due to layer 38 was displayed. When the reflection density at the time of white display was measured by X-rite 404 manufactured by X-rite, it was about 0.3.

  Next, from this white display state, under a 20 ° C. environment, when a DC voltage of 5 V was applied for 5 seconds so that the display electrode 24 became a positive electrode, the display medium 62 was blue. The concentration at this time was measured by X-rite 404 manufactured by X-rite, and was about 1.4. When the environment at 20 ° C. was further maintained, this blue color disappeared in about 1 minute. For this reason, in the structure of the comparative example 1, it can be said that it is difficult to suppress a density | concentration fall compared with the said Examples 1-4.

1 is a schematic configuration diagram illustrating a display device according to a first embodiment. (A) (B) It is an expansion schematic diagram of the display substrate periphery of the display medium which concerns on 1st Embodiment. It is an expansion schematic diagram of the display substrate periphery of the display medium based on 1st Embodiment. It is a schematic diagram which shows an example of the production method of the hollow structure in (A)-(C) 1st Embodiment. (D)-(E) It is a schematic diagram which shows an example of the production method of the hollow structure in 1st Embodiment. (A) (B) It is a conceptual diagram which shows the monomer solution 37A of the state localized to the contact area | region between each particle | grains which comprise a colloid particle structure at the time of preparation of the hollow structure in 1st Embodiment. is there. It is a flowchart which shows the process performed by CPU of the display apparatus in 1st Embodiment. (A)-(E) It is a schematic diagram which shows a mode that the 1st particle | grains of a display medium enter / exit with respect to a hollow structure in 1st Embodiment. It is a schematic diagram which shows a different form from the display medium shown in FIG. 1 in 1st Embodiment. It is a schematic diagram which shows a different form from the display medium shown in FIG. 1 in 1st Embodiment. (A)-(E) It is a schematic diagram which shows the form different from the form shown in FIG. 8 in 1st Embodiment. It is a schematic block diagram which shows the display apparatus in 2nd Embodiment. It is a flowchart which shows the process performed by CPU of the display apparatus in 2nd Embodiment. (A)-(E) It is a schematic diagram which shows a mode that the 1st particle | grains of a display medium enter / exit with respect to a hollow structure in 2nd Embodiment. It is a schematic block diagram which shows the display apparatus in 3rd Embodiment. It is a flowchart which shows the process performed by CPU of the display apparatus in 3rd Embodiment. (A)-(E) It is a schematic diagram which shows a mode that the 1st particle | grains of a display medium enter / exit with respect to a hollow structure in 3rd Embodiment. It is a schematic block diagram which shows the display apparatus in 4th Embodiment. It is a flowchart which shows the process performed with CPU of the display apparatus in 4th Embodiment. (A)-(E) It is a schematic diagram which shows a mode that the 1st particle | grains of a display medium enter / exit with respect to a hollow structure in 4th Embodiment. It is a schematic block diagram which shows the display apparatus in 5th Embodiment. It is a flowchart which shows the process performed by CPU of the display apparatus in 5th Embodiment. (A)-(E) It is a schematic diagram which shows a mode that the 1st particle | grains of a display medium enter / exit with respect to a hollow structure in 5th Embodiment. It is a schematic block diagram which shows the display apparatus in 6th Embodiment. It is a flowchart which shows the process performed by CPU of the display apparatus in 6th Embodiment. (A)-(E) It is a schematic diagram which shows a mode that the 1st particle | grains of a display medium enter / exit with respect to a hollow structure in 6th Embodiment.

Explanation of symbols

10, 10A, 10B, 10C, 60, 60A, 70, 70A Display device 12, 12A, 12B, 12C, 62, 62A, 72, 72A Display medium 13, 13C, 64, 64A, 74, 74A Writing device 14 Voltage Application unit 16, 50, 67, 71, 77, 79 Control unit 17 Image information acquisition unit 18 Display substrate 20 Back substrate 26A First space 26, 90A, 90B Hollow structure 26B Connection hole 31 Constraining layers 36, 36A, 36B 36C First particle 38 Intermediate layer 42 Dispersion medium 68 Heating member 69 Temperature detection unit 78 Light irradiation unit

Claims (29)

A display substrate that transmits at least visible light; and
A rear substrate disposed facing the display substrate with a gap;
First particles encapsulated between the display substrate and the back substrate and moving between the display substrate and the back substrate according to the electric field by forming an electric field between the substrates;
A dispersion medium sealed between the display substrate and the back substrate;
A first space that is arranged at least in the surface direction of the display substrate facing the rear substrate and in which at least a plurality of the first particles can exist, and the pore diameter changes due to the application of the first stimulus. At least the first particle communicates with the outside in the open state with the largest pore diameter, and the first particle enters the first space from the outside in at least the open state. A hollow structure that includes a coupling hole through which the light passes, and transmits at least light in the visible light region,
A display medium comprising:   The display medium according to claim 1, wherein the hole diameter of the connection hole is larger than a volume average primary particle diameter of the first particle in the opened state.   The display medium according to claim 1, wherein the hole diameter of the connection hole is 2/3 or less of the hole diameter in the open state in the closed state where the hole diameter is the smallest.   The display according to any one of claims 1 to 3, wherein the hole diameter of the connection hole is smaller than a volume average primary particle diameter of the first particle in a closed state where the hole diameter is the smallest. Medium.   The display medium according to any one of claims 1 to 4, wherein the hole diameter of the connection hole is smaller than the diameter of the first space at least in the opened state.   The display medium according to claim 1, wherein the connecting hole further communicates with the adjacent first space at least in the opened state.   The display medium according to claim 1, wherein the first stimulus is any one of an electric field, light, heat, and pH.   The display medium according to claim 1, wherein the first spaces of the hollow structures are regularly arranged at least in a surface direction of the display substrate.   A plurality of the first spaces of the hollow structure are arranged in a direction in which the display substrate and the substrate face each other, and the connection holes communicate with the first spaces adjacent at least in the opened state. The display medium according to any one of claims 1 to 8, wherein:   The display medium according to claim 9, wherein the first space of the hollow structure is regularly arranged in a direction in which the display substrate and the back substrate face each other.   The first space can hold at least a plurality of the first particles by aggregating the first particles by a repulsive force between the first particles and an inner wall. The display medium according to claim 10.   The display medium according to claim 1, wherein the first particles are aggregated or dispersed by applying a second stimulus.   The display medium according to claim 12, wherein the second stimulus is any one of an electric field, light, and heat.   The display medium according to claim 12, wherein the second stimulus is the same stimulus as the first stimulus.   The first particles include a plurality of types of particles that have different absolute values of voltages necessary for moving in accordance with an electric field and are colored in different colors. 14. The display medium according to any one of 14.   Disposed between the display substrate and the back substrate and having a first hole through which the first particles pass at least in the direction in which the display substrate and the back substrate face each other and different from the first particles. The display medium according to claim 1, further comprising an intermediate layer having a color.   The display medium according to claim 16, wherein the intermediate layer is an aggregate of a plurality of second particles.   The display medium according to claim 16, wherein the intermediate layer is a nonwoven fabric.   The display medium according to claim 16, wherein the intermediate layer is white.   20. The constraining layer, further comprising a constraining layer that is laminated on a side of the back substrate facing the display substrate and has a function of constraining the first particles. The display medium described in 1.   The constraining layer is arranged at least in a plane direction on the side of the display substrate facing the back substrate, and at least a first space in which a plurality of the first particles can exist, and by applying a first stimulus In order for the first particle and the outside to communicate with each other in the open state where the hole diameter changes and at least the hole diameter is the largest, and so that the first particles enter the first space from the outside in at least the open state 21. The display according to any one of claims 1 to 20, wherein the display includes a connecting hole through which the first particle passes, and is a hollow structure body that transmits at least light in a visible light region. Medium. A display substrate that transmits at least light in a visible light region, a back substrate disposed opposite to the display substrate with a gap, and a substrate between the display substrate and the back substrate, wherein an electric field is generated between the substrates. First particles that move between the display substrate and the back substrate in response to the electric field, a dispersion medium sealed between the display substrate and the back substrate, and the display A first space in which at least a plurality of the first particles are arranged in the surface direction of the substrate facing the rear substrate, and a pore diameter is changed by applying a first stimulus, and at least the first space; The first space communicates with the outside in the opening state having the largest pore diameter, and the first particles pass because the first particles enter the first space from the outside in at least the opening state. Do A voltage applying means for applying a voltage between the display substrate and the back substrate of a display medium comprising a connecting hole, and a hollow structure body that transmits at least light in a visible light region;
First stimulus applying means for applying the first stimulus;
Control means for controlling the voltage applying means and the first stimulus applying means according to image information;
A writing device comprising:   23. The image processing apparatus according to claim 22, further comprising an acquisition unit configured to acquire image information, wherein the control unit controls the voltage application unit and the first stimulus applying unit according to the image information acquired by the acquisition unit. The writing device described. The control means, after controlling the voltage application means to apply a voltage for moving the first particles to the display substrate side or the back substrate side between the display substrate and the back substrate,
The writing device according to claim 22 or 23, wherein the first stimulus applying unit is controlled so as to apply a stimulus in which the connection hole is in a closed state having a smallest hole diameter.   25. The first stimulus applying unit according to any one of claims 22 to 24, wherein the first stimulus applying unit applies a stimulus of an electric field, light, or heat as the first stimulus. Writing device. A display substrate that transmits at least light in a visible light region, a back substrate disposed opposite to the display substrate with a gap, and a substrate between the display substrate and the back substrate, wherein an electric field is generated between the substrates. First particles that move between the display substrate and the back substrate in response to the electric field, a dispersion medium sealed between the display substrate and the back substrate, and the display A first space in which at least a plurality of the first particles are arranged in the surface direction of the substrate facing the rear substrate, and a pore diameter is changed by applying a first stimulus, and at least the first space; The first space communicates with the outside in the opening state having the largest pore diameter, and the first particles pass because the first particles enter the first space from the outside in at least the opening state. Do A hollow structure that includes at least a visible light region and includes a coupling hole, and a display medium comprising:
Voltage applying means for applying a voltage between the display substrate and the back substrate of the display medium;
First stimulus applying means for applying the first stimulus;
Control means for controlling the voltage applying means and the first stimulus applying means according to image information;
A display device comprising:   27. The image processing apparatus according to claim 26, further comprising an acquisition unit configured to acquire image information, wherein the control unit controls the voltage application unit and the first stimulus applying unit according to the image information acquired by the acquisition unit. The display device described. The control means, after controlling the voltage application means to apply a voltage for moving the first particles to the display substrate side or the back substrate side between the display substrate and the back substrate,
28. The display device according to claim 26 or 27, wherein the first stimulus applying unit is controlled so as to apply a stimulus in which the connection hole is in a closed state having a smallest hole diameter.   The said 1st stimulus provision means gives the stimulus of any one of an electric field, light, and heat as said 1st stimulus, The any one of Claims 26-28 characterized by the above-mentioned. Display device.

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