Particle movement type display device and image display device with the particle movement type display device

The present invention relates to a particle moving display device in which charged particles are filled between opposing substrates, particularly a particle moving display device capable of color display, and further to an image display device provided with the particle moving display device.

A particle moving display device in which charged particles are filled between opposing substrates and an image display device provided with the particle moving display device are known, but in recent years, the demand for a display device capable of color display has increased. ing. In order to realize this, for example, a particle moving display device has been proposed in which charged particles of different colors are painted separately for each section (cell) of the display area. However, in this case, the work of separately painting the charged particles of each color for each section is very troublesome, and the manufacturing cost of the particle moving display device increases.

Further, as another color-displayable particle-moving display device, a particle-moving display device that performs color display using a color filter has also been proposed (see, for example, Patent Document 1). However, in general, in a particle moving display device, display is performed by reflecting external light without using a backlight or the like. Therefore, in the particle moving display device described in Patent Document 1, light by a color filter is used. Due to the absorption of, the display becomes dark and it becomes difficult to realize a clear color display. Therefore, in order to deal with this, a particle moving display device using three or more types of charged particles having different colors has been proposed (see, for example, Patent Document 2).<patcit num="1"><text>JP 2007-140157</text></patcit><patcit num="2"><text>JP 2007-140129</text></patcit>

<p> The particle moving display device described in Patent Document 2 includes at least two types of charged particles having different colors, and these charged particles have charging characteristics having the same polarity and different electric field thresholds from each other. As a result, only charged particles having an electric field threshold lower than that are selectively moved according to the strength of the electric field applied from the electrodes, and color display is realized. Therefore, in the particle moving display device described in Patent Document 2, the color of the charged particles can be directly visually recognized without passing through a filter, so that it is possible to prevent the display from becoming dark.</p><p> However, in this particle moving display device, since a plurality of types of voltage control are required according to the electric field threshold value of each charged particle, the voltage drive circuit becomes complicated and it is necessary to use an expensive voltage control device. Further, in a state where a plurality of types of charged particles are actually mixed, it is expected that the electric field thresholds of the charged particles will vary and become non-uniform, so that it is difficult to realize an appropriate color display. Further, in order to deal with this, a very complicated voltage control in consideration of the variation of the electric field threshold value is required.</p><p> Therefore, an object of the present invention is a particle-moving display device capable of solving the above-mentioned problems and realizing a clear color display with high reproducibility without using a complicated voltage control or an expensive control device. An object of the present invention is to provide an image display device equipped with a particle moving display device at a low manufacturing cost.</p>

<p> In order to solve the above-mentioned problems, the embodiment of the particle mobile display device according to claim 1 of the present invention is charged with the same polarity (hereinafter referred to as "first polarity") between the opposing substrates. Two or more types of first-polarized charged particles, each of which has a different color and a different moving speed when a voltage is applied, and a polarity opposite to the first polarity (hereinafter referred to as "second polarity"). ), And one or more types of charged particles with a color different from the first polar charged particles, and when there are two or more types of charged particles, each color is different and when a voltage is applied It is characterized in that it is filled with second polar charged particles having different moving speeds.</p><p> According to this embodiment, by using two or more types of charged particles that are charged to the same polarity, have different colors, and have different moving speeds when a voltage is applied, the moving speed of each charged particle can be determined. By using the difference, the charged particles of the color to be displayed are arranged closest to the display surface side, and the application of the voltage is stopped in that state, the display of the desired color can be realized. Further, by using the first charged particles and the second charged particles charged with different polarities, it is possible to display a wider variety of colors.</p><p> Therefore, it is possible to realize a highly reproducible and clear color display without using complicated voltage control or an expensive control device. Further, in the present embodiment, since all kinds of charged particles are uniformly put in each section of the display area, it is not necessary to separately paint the charged particles of each color for each section, and the manufacturing cost of the particle moving display device is reduced. Can be reduced.</p><p> In the embodiment of the particle moving display device according to claim 2 of the present invention, the moving speed of the first polar charged particles or the second polar charged particles is determined according to the relative luminous efficiency of the color of the charged particles. It is characterized by being able to be.</p><p> In the present embodiment, for example, the moving speed of the charged particles of a color having a relatively high luminous efficiency such as green is lowered, and the moving speed of the charged particles of a color having a relatively low luminous efficiency such as red is increased. can do. As a result, since there is no or little color display having high relative luminous efficiency at the time of rewriting, it is possible to realize color display rewriting with less flicker. However, it is not limited to this, and conversely, depending on the application, the moving speed of the charged particles of the color having high luminous efficiency is high, and the moving speed of the electric particles of the color having low luminous efficiency is lowered. Is also possible.</p><p> In the embodiment of the particle mobile display device according to claim 3 of the present invention, the moving speed of the first polar charged particles or the second polar charged particles is determined, the charge amount of each particle is determined, and the type of charge control agent is used. It is characterized in that it is made different depending on the amount of addition.</p><p> According to this embodiment, the amount of charge of the charged particles can be made different depending on the type and the amount of the charge control agent added, so that the force received by the charged particles from the electric field can be made different. As a result, the moving speed of the charged particles can be made different, so that the moving speed of each charged particle can be easily and surely set.</p><p> An embodiment of the particle moving display device according to claim 4 of the present invention is characterized in that the moving speed of the first polar charged particles or the second polar charged particles is made different depending on the shape of each particle. ..</p><p> According to this embodiment, since the moving speed can be made different depending on the shape of the charged particles, the moving speed of each charged particle can be easily and surely set.</p><p> An embodiment of the particle-moving display device according to claim 5 of the present invention is characterized in that the moving speed of the first polar charged particles or the second polar charged particles differs depending on the surface shape of each particle. To do.</p><p> According to this embodiment, since the moving speed can be made different depending on the surface shape of the charged particles, the moving speed of each charged particle can be easily and surely set.</p><p> In the embodiment of the particle moving display device according to claim 6 of the present invention, the moving speed of the first polar charged particles or the second polar charged particles is determined by the means according to claims 2 to 5. It is characterized by differentiating by a combination of at least two means.</p><p> According to this embodiment, by combining means for making the moving speed of each charged particle different, it is possible to easily and surely set a different moving speed for each charged particle in a wide speed range.</p><p> An embodiment of the particle mobile display device according to claim 7 of the present invention is a group of particles composed of at least red, green, and blue charged particles as the first polar charged particles, or at least cyan, magenta, and yellow charged particles. It is characterized in that the second polar charged particle is composed of at least white charged particles.</p><p> According to this embodiment, the three primary colors can be displayed by using the first polar charged particles, and further, by charging only white to different polarities, white with less turbidity can be displayed, so that a clear color can be displayed. Display can be realized.</p><p> An embodiment of the particle mobile display device according to claim 8 of the present invention is characterized in that the first polarity is a positive charge polarity and the second polarity is a negative charge polarity.</p><p> The embodiment of the image display device according to claim 9 of the present invention is installed on the display surface side of the particle mobile display device according to any one of claims 1 to 8 and the particle mobile display device. The electrode is provided with an electrode, an electrode installed on the back side of the particle moving display device, and a voltage control unit for controlling a voltage applied between the electrode on the display surface side and the electrode on the back side. It is characterized in that an image is displayed on a particle moving display device.</p><p> According to this embodiment, it is possible to realize a highly reproducible and clear color display without using a complicated voltage control or an expensive voltage control device.</p><p> In the embodiment of the image display device according to claim 10 of the present invention, the voltage control unit has a potential at which the display side attracts the first polar charged particles and a potential at which the back surface attracts the second polar charged particles. When a voltage is applied to the first polar charged particles to move them so as to reach a position closest to the display side substrate in descending order of the moving speed, the first polar charged particles have the highest moving speed. It is characterized in that the color of the first polar charged particle having the highest moving speed is displayed by stopping the application of voltage when the first polar charged particle reaches a position close to the display side substrate. ..</p><p> According to the present embodiment, the application of the voltage is stopped when the first polar charged particle having the highest moving speed reaches the position closest to the display side substrate, so that the first polar charged particle having the highest moving speed is subjected to. It is possible to display colors, and it is possible to easily realize clear color display simply by controlling the voltage application time without changing the voltage value to be applied according to the electric field threshold or the like. The "closest position to the display side substrate" includes the case where the charged particles of the color to be displayed are arranged at the position in contact with the display side substrate, and the fully charged particles are not in contact with the display side substrate. The case where it is arranged at the position closest to the display side substrate is also included.</p><p> In the embodiment of the image display device according to claim 11 of the present invention, the voltage control unit has a potential at which the display side attracts the first polar charged particles and a potential at which the back surface attracts the second polar charged particles. When a voltage is applied to move the first polar charged particles so as to reach a position closest to the display side substrate in descending order of moving speed, the moving speed is the nth among the first polar charged particles. When the first polar charged particle of (n is an integer of 2 or more) reaches the position close to the display side substrate, the potential relationship between the display side substrate and the back surface substrate is reversed to the position close to the display side substrate. The first polar charged particles that have reached are separated from the position closest to the display side substrate to the back side in descending order of the moving speed, and only the first polar charged particles having the nth moving speed are located near the display side substrate. By stopping the application of the voltage when the state exists in, the color of the first polar charged particle whose movement speed is nth is displayed.</p><p> According to this embodiment, when the charged particles of the color to be displayed after the second moving speed reach the position close to the display side substrate, the potential relationship between the display side substrate and the back surface substrate is inverted, and the charged particles The color of the charged particles can be displayed by stopping the application of the voltage when only the particles are present near the display side substrate. That is, according to the present embodiment, the voltage application time and the display side substrate and the back surface are not changed according to the electric field threshold value or the like for the charged particles of any color having the second or later moving speed. A clear color display can be easily realized simply by controlling the potential relationship with the substrate.</p><p> In the embodiment of the image display device according to claim 12 of the present invention, the voltage control unit performs a voltage such that the display side has a potential for attracting the first polar charged particles and the back side has a potential for attracting the second polarity. Is applied to move the first polar charged particles so as to reach a position closer to the display side substrate in descending order of the moving speed, the moving speed is nmth (n) among the first polar charged particles. Is an integer of 2 or more, m is an integer of 1 or more and satisfies n&gt; m), the first polar charged particle reaches a position close to the display side substrate, and the first polar charged particle having the nth moving speed The potential relationship between the display side substrate and the back surface substrate is reversed at a predetermined timing before reaching the position closest to the display side substrate, and the first polar charged particles having the 1st to nth movement speeds are moved at each movement speed. The movement is performed by moving from the display side to the back side and stopping the application of the voltage when only the first polar charged particle having the nth movement speed is present near the display side substrate. It is characterized by displaying the color of the first polar charged particle having the nth velocity.</p><p> According to this embodiment, the potential relationship between the display side substrate and the back surface substrate is reversed before the charge particles of the display color having the second or later moving speed reach the position close to the display side substrate, and only the charged particles are used. The color of the charged particles can be displayed by stopping the application of the voltage when is in a state of being close to the display side substrate. That is, according to the present embodiment, the voltage application time and the display side substrate and the back surface are not changed according to the electric field threshold value or the like for the charged particles of any color having the second or later moving speed. By simply controlling the potential relationship with the substrate, it is possible to achieve a clear color display easily and efficiently in terms of time.</p><p> In the embodiment of the image display device according to claim 13 of the present invention, the voltage control unit has a potential at which the display side attracts the first polar charged particles and a potential at which the back surface attracts the second polar charged particles. When a voltage is applied to the first polar charged particles so that they reach a position closest to the display side substrate in descending order of movement speed, or when the potential relationship between the display side substrate and the back surface substrate is reversed thereafter. In addition, by stopping the application of the voltage in a state where the first polar charged particles of a plurality of colors are present near the display side substrate, the first polar charged particles existing near the display side substrate are present. It is characterized by displaying a mixed color of the above colors.</p><p> According to this embodiment, by stopping the application of the voltage in a state where the charged particles of a plurality of colors are present near the display side substrate, the mixed color of the colors of these charged particles can be displayed. A wider variety of color displays can be realized. In addition, the display rewriting time can be shortened to reduce power consumption.</p><p> An embodiment of the image display device according to claim 14 of the present invention is to apply a voltage obtained by inverting the potential relationship between the display side substrate and the back side substrate with respect to the applied voltage according to any one of claims 10 to 13. It is characterized in that the color of the second polar charged particle is displayed by the above.</p><p> According to this embodiment, since the color of the second polar charged particles can be displayed, it is possible to easily realize a clear color display with high reproducibility for various colors.</p>

<p> As described above, in the particle moving display device and the image display device according to the present invention, highly reproducible and clear color display can be realized without using complicated voltage control or expensive voltage control device. .. Further, in the present invention, since all kinds of charged particles are uniformly put in each section of the display area, it is not necessary to separately paint the charged particles of each color for each section, and the particle moving display device and the image display device can be used. The manufacturing cost can be reduced.</p>

Embodiments of the particle moving display device and the image display device according to the present invention will be described in detail below with reference to the drawings. (Explanation of One Embodiment of the Particle Mobile Display Device According to the Present Invention) First, the outline of the structure of one embodiment of the particle mobile display device according to the present invention will be described with reference to FIG. In the present embodiment, a wet display device filled with a display medium containing charged particles in the solvent will be described as an example. However, the present invention is not limited to this, and it is also possible to use a dry display device filled with only charged particles. Further, an inert gas or a dry gas may be filled together with the charged particles.

Here, FIG. 1 is a plan view of the particle moving display device 2 (referred to as display device 2 in the following description) according to the present invention as viewed from the display surface side, and is one of the display side substrates 4. The part is cut out so that the inside is exposed. As is clear from the cutout portion in FIG. 1, in this display device 2, the display area surrounded by the partition wall 14 is formed in a cross shape when viewed from the display surface side, and is a partition wall for dividing the display area. A plurality of 8s are arranged, and a plurality of substantially square compartments 40 divided by a partition wall 8 are formed for each pixel. That is, when the partition walls 8 are formed in a grid pattern, the partition walls 8 are not continuous in the region between the intersections of the orthogonal partition walls 8 and have a predetermined gap. However, the present invention is not limited to this, and an embodiment in which the grid-like partition walls 8 are continuously formed can be considered. Further, in the present embodiment, the partition 40 divided by the partition wall 8 is provided for each pixel, but the present invention is not limited to this, and the partition wall 8 is provided for each of a plurality of pixels to include a plurality of pixels. A compartment 40 can also be formed.

Further, FIGS. 2 and 3 are side sectional views seen from the arrow AA of FIG. 1, and schematically show the internal structure of the display device 2. The upper surface in FIGS. 2 and 3 is the display surface, and the lower surface is the back surface. Here, FIG. 2 shows a 4-particle system display device 2 containing four types of charged particles having different colors, and FIG. 3 shows a five-particle system containing five types of charged particles having different colors. Display device 2 is shown. The color of the charged particles means a color that can be visually recognized when the charged particles are viewed from the outside.

First, the four-particle system display device 2 shown in FIG. 2 will be described. As shown in FIG. 2, the display device 2 is located between a display-side substrate 4 having a common electrode 10, a back-side facing substrate 6 having a pixel electrode 12, and a display-side substrate 4 and a facing substrate 6. It is mainly composed of the provided partition wall 8. In the present embodiment, the display device 2 is divided into partition walls 8 for each pixel, and individual pixel electrodes 12 are provided for each partition 40 divided by the partition wall 8. Further, in the display side substrate 4, electrodes are also provided in the portion where the partition wall 8 is not continuous, whereby the electrodes of the respective compartments 40 divided by the partition wall 8 are electrically connected to each other, and the common electrode 10 is formed. Is forming.

The common electrode 10 and the pixel electrode 12 are arranged so as to face each other by the height of the partition wall 8, excluding the thickness of the electrode. The image display device provided with the display device 2 and displaying an image on the display device 2 further includes a voltage control unit for controlling the voltage applied between the common electrode 10 and the pixel electrode 12, and is equipped with the common electrode 10. By generating an electric field having a predetermined polarity and a predetermined intensity between the pixel electrodes 12, the charged particles enclosed between the two electrodes can be moved to rewrite the display.

In the present embodiment, a display medium containing four types of charged particles 30 to 36 in the solvent is enclosed in a closed space formed between the common electrode 10 and the pixel electrode 12. In this embodiment, methacrylic resin (PMMA) is used as the material for the charged particles 30 to 36, but the material is not limited to this, and other materials such as fluorinated acrylic resin, polypropylene (PC), and high density are used. Density polyethylene (HDPE), polypropylene (PP), acrylonitrile butadiene styrene (ABS), polyethylene terephthalate (PET), polyacetal (POM), polystyrene (PS) and the like can be used. Further, as a means for developing the colors of the charged particles 30 to 36 into a desired color, it is conceivable to use the color originally possessed by the raw material, or to add a coloring material of the desired color to the raw material, and to form the particles. It is also conceivable to form a coating layer or coating layer of a desired color on the surface of the charged particles, or any other coloring means can be used. Further, as the solvent, a solvent such as a hydrocarbon or silicone oil having high insulating properties can be appropriately used.

More specifically, as shown in FIG. 2, the charged particles are negatively charged white charged particles 30 (hereinafter referred to as white charged particles 30"" in the space between the common electrode 10 and the pixel electrode 12. ), Positively charged red charged particles 32 (hereinafter referred to as "red charged particles 32"), positively charged blue charged particles 34 (hereinafter referred to as "blue charged particles 34"), And four types of charged particles of positively charged green charged particles 36 (hereinafter, referred to as "green charged particles 36") are enclosed. All of these charged particles 30 to 36 have a spherical shape having the same radius. Here, the moving speeds of the positively charged red charged particles 32, the blue charged particles 34, and the green charged particles 36 when a voltage is applied between the electrodes 10 and 12, respectively, are Vr. , Vb, Vg, in this embodiment, there is a relationship of Vr&gt; Vb&gt; Vg.

In this embodiment, positively charged blue, red, and green (three primary colors of light) charged particles are used, but the present invention is not limited to this, and for example, cyan, magenta, and yellow (three primary colors of pigment) are used. ) Charged particles can also be used. A detailed description of the display rewriting method using these charged particles 30 to 36 will be described later with reference to FIGS. 4A to 4F.

As the dimensions of the display device 2 of the present embodiment, for example, the width of the compartment 40, that is, the distance between the adjacent partition walls 8 is 250 μm, and the distance between the electrodes 10 between the common electrode 10 and the pixel electrode 12 is 40 μm. can do. However, the dimensions of the display device 2 are not limited to this, and any other dimension can be adopted.

To outline the material of the display device 2 of the present embodiment, the display side substrate 4 is formed of a material having high transparency and high insulating property, for example, polyethylene naphthalate, polyether sulfone, polyimide, polyethylene terephthalate. Resin materials such as, glass materials, and the like can be used. Further, the common electrode 10 is formed of a material having high transparency and can be used as an electrode, and for example, a conductive oxide such as ITO (Indium Tin Oxide) or a conductive polymer can be used. Further, the facing substrate 6 is formed of a material having high insulating properties, and for example, a material such as glass or a metal film having an insulating coating treatment or a resin material such as polyethylene terephthalate can be used. The facing substrate 6 may be transparent or opaque, unlike the display substrate 4. Further, for the pixel electrode 12, for example, in addition to the same material as the common electrode 10, an opaque material such as a copper material can be used. Further, for the partition wall 8, the same material as that of the facing substrate 6 can be used.

Next, the five-particle system display device 2 shown in FIG. 3 will be described. The difference from the above-mentioned 4-particle system display device 2 is that, in addition to the above-mentioned four types of charged particles 30 to 36, a positively charged black spherical charged particle 38 (hereinafter referred to as "black charged particle 38") is described. Is enclosed in the space between the common electrode 10 and the pixel electrode 12. That is, in the 5-particle system display device 2 shown in FIG. 3, negatively charged white charged particles 30, positively charged red charged particles 32, blue charged particles 34, green charged particles 36, and black charged particles 38 are enclosed. ing. The black charged particles 38 are made of the same material as the other charged particles 30 to 36.

Here, a voltage was applied between the electrodes 10 and 12 of the positively charged red charged particles 32, the blue charged particles 34, the green charged particles 36, and the black charged particles 38. Assuming that the moving speeds are Vr, Vb, Vg, and Vbk, respectively, in this embodiment, there is a relationship of Vr&gt; Vb&gt; Vg&gt; Vbk. In other respects, the 5-particle system display device 2 shown in FIG. 3 is basically the same as the 4-particle system display device 2 shown in FIG. 2, including the dimensions and materials. A detailed description of the display rewriting method using these charged particles 30 to 38 will be described later with reference to FIGS. 5A to 5H.

(Explanation of Display Rewriting Method in Display Device According to the Present Invention) Next, a method of rewriting the display in the 4-particle system display device 2 shown in FIG. 2 and the 5-particle system display device 2 shown in FIG. 3 will be described. &lt;4 Explanation of display rewriting method in particle-based display device&gt; First, a method of rewriting the display in the 4-particle system display device 2 will be described with reference to FIGS. 4A to 4F.

As shown in FIGS. 4A to 4F, negatively charged white charged particles 30 and positively charged red charged particles 32, blue charged particles 34, and green charged particles 36 having different moving speeds are used. White display (see Fig. 4A), red display (see Fig. 4B), blue display (see Fig. 4D), black display (see Fig. 4E), green display (see Fig. 4F), etc. can be performed. As described above, in the present embodiment, the moving speed Vr of the positively charged red charged particles 32, the moving speed Vb of the blue charged particles 34, and the moving speed Vg of the green charged particles 36 are Vr&gt; Vb&gt; Vg. Has a relationship of.

That is, of the three positively charged particles, the red charged particle 32, which has the lowest luminous efficiency, has the highest moving speed Vr, and the green charged particle 36, which has the highest luminous efficiency, has the lowest moving speed Vg. It has become. More specifically, for example, assuming that the distance L between the common electrode 10 and the pixel electrode 12 is 40 μm, the fastest moving speed Vr of the red charged particles 32 is reached in about 50 msec. The speed that can be achieved (Vr = 40 μm / 50 msec = 800 μm / sec) can be set, and the moving speed Vg of the slowest green charged particles 36 can be set to the speed that can be reached in about 100 msec (Vg = 40 μm / 100 msec = 400 μm / sec). Further, the moving speed Vb of the blue charged particles having an intermediate speed can be set to a substantially intermediate value between Vr and Vg. Note that this moving speed is an example, and any other moving speed can be adopted.

&lt;&lt; Explanation of means to make a difference in the moving speed of charged particles &gt;&gt; The following means can be considered as means for making a difference in the moving speed of each charged particle. Means 1: The amount of charge of the charged particles can be different from the force received from the electric field by making the type of charge control agent and the amount of addition different. When an electric field of the same strength is applied to a charged particle, the charged particle with a large amount of charge receives a larger force from the electric field, so that the moving speed becomes a high value, and the charged particle with a small amount of charge receives from the electric field. Since the force is small, the moving speed is low. Here, examples of the charge control agent for imparting positive chargeability include quaternary ammonium salts and niglosin dyes, while the charge control agent for imparting negative chargeability includes, for example, metal-containing salicylic acid. Examples thereof include a complex and a chloro-containing organic dye. However, the present invention is not limited to this, and any other charge control agent can be used. Further, the charge amount of the charged particles can be controlled by a surface treatment agent for externally adding the particle surface, for example, silica fine particles, or the charge amount can be controlled by combining these.

Means 2: Different shapes of charged particles By making the shape of the charged particles different, the magnitude of the flow resistance can be made different, and even if the same force is applied from the electric field, the moving speed can be made different. For example, comparing a spherical charged particle of the same volume with a disk-shaped charged particle having an oval cross-sectional shape, if the same force is applied from an electric field, the disk-shaped charged particle is most projected. Since the surface having a smaller area moves in a posture perpendicular to the moving direction, the disk-shaped charged particles can have a smaller flow resistance during movement than the spherical charged particles. Therefore, the disk-shaped charged particles can move at a higher speed than the spherical charged particles. The disk-shaped and spherical shapes are merely examples, and any other shape can be used to make a difference in the moving speed of the charged particles.

Means 3: Different surface shapes of charged particles By making the surface shape of the charged particles different, the magnitude of the flow resistance can be made different, and even if the same force is applied from the electric field, the moving speed can be made different. For example, in the case of charged particles having the same surface shape other than the surface shape, comparing the charged particles having a smooth surface shape and the charged particles having an uneven shape on the surface, even if the same force is applied from the electric field. Since the flow resistance of the charged particles having a smooth surface shape is smaller than the flow resistance of the charged particles having an uneven shape, the moving speed can be increased. The above surface shape is just an example, and any other surface shape can be used to make a difference in the moving speed of the charged particles.

The means for making the moving speeds of the charged particles different as described above can be used individually or in combination of a plurality of means. As a result, it is possible to make a clear difference in the moving speed of each charged particle, and by extension, it is possible to realize a clear color display with high reproducibility. The means for changing the moving speed of the charged particles is not limited to the above, and any other method can be used.

&lt;&lt; Explanation of Figure 4A &gt;&gt; In the display device 2 in which the charged particles 30 to 36 as described above are enclosed, first, as shown in FIG. 4A, the common electrode 10 on the display surface side becomes the positive electrode, and the pixel electrode 12 on the back surface side becomes the negative electrode. A voltage is applied to form an electric field. As a result, the negatively charged white charged particles 30 move to a position near the display side substrate 4 or in contact with the display side substrate 4 (hereinafter, referred to as "closest position to the display side substrate"), and are positively charged red charge. The particles 32, the blue charged particles 34, and the green charged particles 36 move to a position in the vicinity of the facing substrate 6 on the back surface side or in contact with the facing substrate 6 (hereinafter, referred to as "closest position to the back surface side substrate"). When the voltage application is stopped in this state, the positional relationship of the charged particles 30 to 36 is maintained. When this state is viewed from the display surface side, since the layer of the white charged particles 30 is arranged at the position closest to the display surface side, the compartment 40 divided by the partition wall 8 is displayed in white.

&lt;&lt; Explanation of Figure 4B &gt;&gt; From this white display state, the potential relationship between the electrode 10 and the electrode 12 in the case of FIG. 4A is inverted, and the voltage is applied so that the common electrode 10 on the display surface side becomes the negative electrode and the pixel electrode 12 on the back surface side becomes the positive electrode. Apply. Due to the electric field formed by this, the negatively charged white charged particles 30 located near the display side substrate move to the back side, and the positively charged red charged particles 32 and blue charged particles 34 located near the back side substrate move. , And the green charged particles 36 move to the display surface side. In this case, the positively charged charged particles 32, 34, and 36 move in descending order of moving speed (Vr&gt; Vb&gt; Vg) so as to reach the position closest to the display side substrate. That is, when the voltage application is continued, the red charged particles 32, the blue charged particles 34, and the green charged particles 36 reach the positions closest to the display side substrate in this order.

Here, as shown in FIG. 4B, when the voltage application is stopped when the red charged particles 32 reach the position close to the display side substrate, the positional relationship of the charged particles 30 to 36 is maintained. When this state is viewed from the display surface side, since the layer of the red charged particles 32 is arranged at the position closest to the display surface side, the compartment 40 divided by the partition wall 8 is displayed in red. As described above, it is possible to display the color of the red charged particles 32 having the highest moving speed among the plurality of types of positively charged charged particles 32 to 36.

&lt;&lt; Explanation of Figure 4C &gt;&gt; From this red display state, when a voltage is applied so that the same potential relationship, that is, the common electrode 10 on the display surface side becomes the negative electrode and the pixel electrode 12 on the back surface side becomes the positive electrode, red charging is performed as shown in FIG. 4C. Following the particles 32, the blue charged particles 34 reach a position close to the display side substrate. From the white display shown in FIG. 4A, when the voltage application is continued as it is without stopping the voltage application when the red charged particles 32 reach the position close to the display side substrate, the white display shown in FIG. 4A is displayed. It can be continuously changed up to the state shown in Fig. 4C. Further, in FIG. 4C, the white charged particles 30 have not yet reached the position close to the back surface substrate, and are located at a position Lw away from the common electrode 10. This distance Lw will be described in detail later in the description of the relational expression of the moving speed of the charged particles.

It can be said that the state shown in FIG. 4C is in the middle of rewriting to shift from the red display shown in FIG. 4B to the blue display shown in FIG. 4D or the black display shown in FIG. 4E. In this case, the positional relationship of each of the charged particles 30 to 36 is maintained, and a mixed color of red and blue (that is, purple) can be displayed. In the section 40 corresponding to each pixel, the three primary colors of red, blue, and green are displayed, and the mixed color is basically displayed by the combination of the pixels displayed in the three primary colors. It is also possible to display mixed colors in each pixel. This is a method that cannot be realized by color display using a color filter, enables more diverse color display, and can contribute to shortening the display rewriting time and reducing power consumption.

&lt;&lt; Explanation of Figure 4D &gt;&gt; Next, when the blue charged particles 34 reach a position close to the display side substrate (see FIG. 4C), the potential relationship between the electrode 10 and the electrode 12 is reversed, and the common electrode 10 on the display surface side becomes the positive electrode, and the back side becomes the positive electrode. A voltage is applied so that the pixel electrode 12 of the above becomes a negative electrode. As a result, the positively charged red-charged particles 32 and the blue-charged particles 34, which were close to the display surface side substrate, move to the back side in descending order of moving speed (Vr&gt; Vb). That is, as shown in FIG. 4D, a state is formed in which the red-charged particles 32 advance to the back side of the blue-charged particles 34 and only the blue-charged particles 34 are close to the display-side substrate.

When the voltage application is stopped at this point, the positional relationship of the charged particles 30 to 36 is maintained, and when this state is viewed from the display surface side, the layer of the blue charged particles 34 is arranged at the position closest to the display surface side. Therefore, the compartment 40 divided by the partition wall 8 is displayed in blue. In this case, in order to realize a clear blue display, the white charged particles 30 moving to the display surface side should be closer to the display surface side than the blue charged particles 34 due to the reversal of the potential relationship between the electrodes 10 and 12. This needs to be prevented, but this will be explained in detail later.

In the case shown in FIG. 4D, the layer of the blue charged particles 34 is arranged at the position closest to the display surface, but the blue charged particles 34 also move to the back side due to the formed electric field, so that the blue charged particles 34 are charged in blue. The particles 34 are arranged not in contact with the common electrode 10 but at a position some distance from the common electrode 10. However, since the contrast of the displayed image does not differ greatly depending on the distance from the common electrode 10 (display surface), the color of the charged particles arranged at the position closest to the display surface can be clearly displayed.

&lt;&lt; Explanation of Figure 4E &gt;&gt; Next, when the blue charged particles 34 reach a position close to the display side substrate (see FIG. 4C), the common electrode 10 on the display surface side becomes the negative electrode without reversing the potential relationship between the electrode 10 and the electrode 12, and the back surface becomes the negative electrode. When the voltage application is continued so that the pixel electrode 12 on the side becomes the positive electrode, the green charged particles 36 reach the position closest to the display side substrate following the red charged particles 32 and the blue charged particles 34. Further, in FIG. 4E, the white charged particles 30 also reach a position close to the back surface side substrate. When the voltage application is stopped at this point, the positional relationship between the charged particles 30 to 36 is maintained, and when this state is viewed from the display surface side, the red charged particles 32 and the blue charged particles are located at the positions closest to the display surface. Since the three primary colors of 34 and the green charged particles 36 are arranged, the compartment 40 divided by the partition wall 8 is displayed in a dark color (black) which is a mixed color of them.

&lt;&lt; Explanation on the 4th floor &gt;&gt; Next, following the red charged particles 32 and the blue charged particles 34, when the green charged particles 36 reach the position closest to the display side substrate (see FIG. 4E), the potential relationship between the electrode 10 and the electrode 12 is reversed. A voltage is applied so that the common electrode 10 on the display surface side serves as a positive electrode and the pixel electrode 12 on the back surface side serves as a negative electrode. As a result, the positively charged red-charged particles 32, blue-charged particles 34, and green-charged particles 36 that were close to the display surface-side substrate move to the back side in descending order of moving speed (Vr&gt; Vb&gt; Vg). .. That is, as shown in FIG. 4F, the red-charged particle 32 advances to the back side of the blue-charged particle 34, the blue-charged particle 34 advances to the back side of the green-charged particle 36, and only the green-charged particle 36 is on the display side. A state of being close to the substrate is formed.

When the voltage application is stopped at this point, the positional relationship of the charged particles 30 to 36 is maintained, and when this state is viewed from the display surface side, the layer of the green charged particles 36 is arranged at the position closest to the display surface side. Therefore, the display area partitioned by the partition wall 8 is displayed in green. In this case, in order to realize a clear green display, the white charged particles 30 that move to the display surface side due to the reversal of the potential relationship between the electrodes 10 and 12 are closer to the display surface side than the green charged particles 36. It is necessary to prevent this, but this point will be explained in detail later.

As described above, as shown in the blue display shown in FIG. 4D and the green display shown in FIG. 4F, among the two types of positively charged charged particles 32 to 36, the charged particles having the second or later movement speed are described. When the charged particles reach the position closest to the display side substrate, the potential relationship between the electrodes 10 and 12 is reversed so that the charged particles are placed at the position closest to the display surface and the color of the charged particles is displayed. can do. As the number of a plurality of types of charged particles charged with the same polarity, three charged particles 32 to 36 are used in the four-particle system embodiment, and four charged particles 32 to 38 are used in the five-particle system embodiment described later. Although it is used, it is not limited to these, and any number of other charged particles can be used.

That is, in general terms applicable to an arbitrary number of charged particles, in the display device according to the present invention, the positively charged moving speed is the nth (n is an integer of 2 or more) charged particles. When it reaches the position closest to the display side substrate, the potential relationship between the electrodes 10 and 12 is reversed, and the charged particles that reach the position closest to the display side substrate are moved to the back side in descending order of the moving speed, and the moving speed is increased. When only the nth charged particle is present near the display side substrate, the color of the charged particle can be displayed by stopping the application of the voltage.

Further, in the present embodiment, when the charged particles of the displayed color (for example, the blue charged particles 34 and the green charged particles 36) reach the position close to the display side substrate, the potential relationship between the electrodes 10 and 12 is reversed. However, the present invention is not limited to this, and the potential relationship between the electrodes 10 and 12 is reversed before the charged particles of the displayed color reach the position closest to the display side substrate, and the charged particles are moved in descending order of moving speed. It can also be moved to the back side. In this case, the charged particles having a higher moving speed than the charged particles of the displayed color move to the back side overtaking the charged particles of the displayed color, and only the charged particles of the displayed color are placed at the position closest to the display surface. Can be placed.

In general terms, which can be applied to an arbitrary number of charged particles, in the display device according to the present invention, the moving speed is nm-th (n is 2 or more) among the positively charged charged particles. The electrode 10 is the time before the charged particles of (m is an integer greater than or equal to 1 and satisfies n&gt; m) reach the position near the display side substrate, and the charged particles with the nth moving speed reach the position near the display side substrate. By reversing the potential relationship between the particle and the electrode 12, the charged particles with the 1st to nth moving speeds are moved from the display side to the back side at each moving speed, and only the charged particles with the nth moving speed are close to the display side substrate. By stopping the application of the voltage when the state exists at the position, the color of the charged particle can be displayed.

As described above, the 4-particle system display device 2 using the negatively charged white charged particles 30, the positively charged red charged particles 32, the blue charged particles 34, and the green charged particles 36, which are positively charged and have different moving speeds, respectively. Therefore, the three primary colors of white, black, red, blue, and green, and their mixed colors can be displayed in the compartment 40 divided by the partition wall 8 corresponding to each pixel. In this case, without performing voltage control using the electric field threshold value, that is, without using complicated voltage control or an expensive voltage control device, control of the application time when applying a voltage of a constant value, and electrodes 10 and 12 A clear color display with high reproducibility can be easily realized only by the inversion control of the potential relation of. Further, since the charging polarity of the white charged particles 30 is the opposite polarity of the charging polarity of the charged particles of other colors, it is possible to display white with less turbidity.

Further, in the present embodiment, since it is not necessary to separately apply charged particles of each color to each section 40 surrounded by the partition wall 8, it is possible to facilitate the manufacture of the display device 2 for color display and reduce the manufacturing cost thereof. .. Further, in the present embodiment, the moving speed of the red charged particles 30 having a relatively low luminous efficiency is set to be high, and the moving speed of the green charged particles 36 having a relatively high luminous efficiency is set to be low. Sometimes there is no or little color display with high luminous efficiency, so it is possible to rewrite the color display with less flicker.

As described above, it is desirable to set the moving speed of the charged particles having a low luminous efficiency faster than the moving speed of the charged particles having a high luminous efficiency. The moving speeds of the plurality of types of charged particles may be set faster in ascending order of relative luminous efficiency, but it is not necessary to strictly set the moving speeds of all charged particles in ascending order of relative luminous efficiency. For example, consider the case where charged particles A, charged particles B, charged particles C, and charged particles D are present in descending order of relative luminous efficiency. At this time, if the moving speed of the charged particles A, which is the most cause of the flicker, is set to be the slowest, the flicker can be caused to some extent even if the moving speeds of the remaining types of charged particles are not set to be faster in ascending order of relative luminous efficiency. Can be prevented. Alternatively, if there is not much difference between the relative sensitivity of the charged particle B and the relative sensitivity of the charged particle A, the moving speed of each particle is increased in descending order of the charged particle D, the charged particle C, the charged particle A, and the charged particle B. It may be set so as to be.

Further, for example, when the color of the charged particle C is not displayed so much, the moving speed of the charged particle C may be set to be slower than the moving speed of the charged particle A and the charged particle B. In this case, the moving speed of each charged particle is charged particle D, charged particle B, charged particle A, and charged particle C in descending order. In this way, in at least one set (for example, charged particles A and D, or charged particles B and D), the moving speed of the one having the higher relative sensitivity is slower than the one having the lower relative sensitivity (for example). If the moving speed of the charged particle A is slower than the moving speed of the charged particle D, or the moving speed of the charged particle B is slower than the moving speed of the charged particle D), flicker can be suppressed at the time of rewriting. be able to. As described above, if the moving speeds of the plurality of types of charged particles are set faster in ascending order of relative sensitivity (for example, charged particles D, charged particles C, charged particles B, and charged particles A in descending order of moving speed). (If it is set to be), it is possible to display all colors with the least flicker at the time of rewriting.

&lt;5 Explanation of display rewriting method in particle-based display device&gt; Next, a method of rewriting the display in the 5-particle system display device 2 will be described with reference to FIGS. 5A to 5H. As shown in FIGS. 5A to 5H, negatively charged white charged particles 30, positively charged red charged particles 32, blue charged particles 34, green charged particles 36, and black-green charged particles have different moving speeds. Using 38, white display (see Fig. 5A), red display (see Fig. 5B), blue display (see Fig. 5D), green display (see Fig. 5F), black display (see Fig. 5G, H), etc. be able to. As described above, in the present embodiment, the moving speed Vr of the positively charged red charged particles 32, the moving speed Vb of the blue charged particles 34, the moving speed Vg of the green charged particles 36, and the moving speed of the black charged particles 38. For Vbk, there is a relationship of Vr&gt; Vb&gt; Vg&gt; Vbk.

More specifically, the moving speed of each charged particle is described in more detail. For example, assuming that the distance L between the common electrode 10 and the pixel electrode 12 is 40 μm, the fastest moving speed Vr of the red charged particles is about the distance between the electrodes. The speed that can be reached in 50 msec (Vr = 40 μm / 50 msec = 800 μm / sec), and the moving speed Vbk of the slowest black charged particle 38 should be the speed that can be reached in about 100 msec (Vbk = 40 μm / 100 msec = 400 μm / sec). Can be done. Further, the moving speeds Vb and Vg of the blue charged particles 34 and the green charged particles 36 having intermediate speeds can be set to equal values between the moving speeds Vr and Vbk. However, these are examples and can be set to any other moving speed.

&lt;&lt; Explanation of Figures 5A to 5F &gt;&gt; In the display device 2 in which the charged particles 30 to 38 are enclosed as described above, the rewriting of the display shown in FIGS. 5A to 5F is not a display using the black charged particles 38, so basically, from FIG. 4A. It is the same as the rewriting of the display shown in Fig. 4F. Therefore, detailed description will be omitted. The rewriting stage of the 5-particle system shown in FIG. 5E corresponds to the dark color (black) display of the 4-particle system shown in FIG. 4E. In FIG. 5E, the red charged particles 32 and the blue charged particles 34, And the green charged particles 36 have reached the position close to the display side substrate, but the black charged particles 38 have not yet reached the position close to the display side substrate. Further, in FIG. 4E, the white charged particles have reached the position close to the back surface substrate, but in FIG. 5E, the white charged particles 30 have not yet reached the position close to the back surface substrate, and the common electrode 10 Lw'away from. This distance Lw'will be described in detail later in the description of the relational expression of the moving speed of the charged particles.

In the case shown in Fig. 5E, it is possible to display a dark color (black) by mixing the three primary colors in the same way as the black display shown in Fig. 4E. In the form, as shown in FIG. 5G or FIG. 5H, a black display using the black charged particles 38 is performed. Further, also in the 5-particle system, as in the case of the 4-particle system described above, by stopping the application of voltage to the electrodes in a state where a plurality of charged particles of different colors are present near the display side substrate, they are formed. It is possible to display a mixed color of the colors of the charged particles of.

&lt;&lt; Explanation of Figure 5G &gt;&gt; As shown in FIG. 5E, with the red charged particles 32, the blue charged particles 34, and the green charged particles 36 reaching the positions close to the display side substrate, the common electrode 10 on the display surface side becomes the negative electrode, and the back side becomes the negative electrode. When the voltage application in which the pixel electrode 12 serves as the positive electrode is continued, the black charged particles 38 reach the position close to the display side substrate as shown in FIG. 5G. The white charged particles 30 also reach a position close to the back surface substrate. When the voltage application is stopped at this point, the positional relationship between the charged particles 30 to 38 is maintained, and when this state is viewed from the display surface side, the black charged particles 38 and the red charged particles 38 are located at the positions closest to the display surface. Since the three primary colors of the particles 32, the blue charged particles 34, and the green charged particles 36 are arranged, the compartment 40 divided by the partition wall 8 is displayed in black (No. 1) depending on the mixed colors of black and the three primary colors. Be done.

&lt;&lt; Explanation of Figure 5H &gt;&gt; Next, when the black charged particles 38 reach the position closest to the display side substrate (see FIG. 5G) following the red charged particles 32, the blue charged particles 34, and the green charged particles 36, the potential relationship between the electrodes 10 and 12 is reached. Is inverted, and a voltage is applied so that the common electrode 10 on the display surface side becomes the positive electrode and the pixel electrode 12 on the back surface side becomes the negative electrode. As a result, the positively charged red-charged particles 32, blue-charged particles 34, green-charged particles 36, and black-charged particles 38 that were close to the display surface-side substrate have high moving speeds (Vr&gt; Vb&gt; Vg&gt; Vbk). ) Move to the back side in order. That is, as shown in FIG. 5H, the red-charged particle 32 advances to the back side of the blue-charged particle 34, the blue-charged particle 34 advances to the back side of the green-charged particle 36, and the green-charged particle 36 advances to the black-charged particle 38. A state is formed in which only the black charged particles 38 are located close to the display side substrate.

When the voltage application is stopped at this point, the positional relationship of the charged particles 30 to 38 is maintained, and when this state is viewed from the display surface side, the layer of the black charged particles 38 is arranged at the position closest to the display surface side. Therefore, the compartment 40 divided by the partition wall 8 is displayed in black (No. 2). In this case, in order to realize a clear black display, the white charged particles 30 that move to the display surface side due to the reversal of the potential relationship between the electrodes 10 and 12 are closer to the display surface side than the black charged particles 38. It is necessary to prevent this, but this point will be explained in detail later.

As described above, a 5-particle system using negatively charged white charged particles 30, positively charged red charged particles 32, blue charged particles 34, green charged particles 36, and black charged particles 38, respectively. The display device 2 can display the three primary colors of white, black, red, blue, and green, and their mixed colors in the compartment 40 divided by the partition wall 8 corresponding to each pixel. In this case, without performing voltage control using the electric field threshold value, that is, without using complicated voltage control or an expensive voltage control device, control of the application time when applying a voltage of a constant value, and electrodes 10 and 12 A clear color display with high reproducibility can be easily realized only by the inversion control of the potential relation of. Further, since the charging polarity of the white charged particles 30 is the opposite polarity of the charging polarity of the charged particles of other colors, it is possible to display white with less turbidity. In particular, in the present embodiment of the 5-particle system, black display with lower brightness can be performed as compared with the above-described four-particle system embodiment, so that a color display with higher contrast can be realized.

(Relational expression regarding the moving speed of each charged particle) Next, in the above-mentioned 4-particle system or 5-particle system display device 2, the moving speed of each positively charged particle and the negatively charged white charged particle, which are necessary for realizing a clear color display, and the negatively charged white particle. The relational expression with the moving speed will be described in detail below.

The following symbols are used in the relational expression regarding the moving speed of charged particles. L: Particle movable distance between the common electrode 10 and the pixel electrode 12 (That is, the distance between the electrodes minus the diameter of 2R of the charged particles 30 to 38) Vw: Movement speed of white charged particles 30 Vr: Movement speed of red charged particles 32 Vb: Moving speed of blue charged particles 34 Vg: Moving speed of green charged particles 36 Vbk: Moving speed of black charged particles 38 R: Radius of charged particles 30 ~ 38

&lt;In the case of a four-particle system embodiment&gt; Relational expression 1: Relational expression when displaying green First, the "relationship formula 1 of the moving speed of charged particles" in the case of displaying green in a four-particle system as shown in FIG. 4F will be described. When displaying green, it is necessary that only the green charged particles 36 are located closest to the display surface side. For that purpose, the blue charged particles 34 and the green charged particles 36 are located from the position closest to the display side substrate to the back surface. When moving to the side, due to the difference in moving speed (Vb-Vg), the blue charged particle 34 needs to overtake the green charged particle 36 by at least one particle 2R. In other words, if the time required at that time is Tbg, then Tbg = 2R / (Vb-Vg).

During this time Tbg, the green charged particles 36 (see Fig. 4E) that were close to the display side substrate moved to the back side at a moving speed of Vg, and the white charged particles 30 that were close to the back surface substrate (see Fig. 4E). However, it moves to the display surface side at the moving speed Vw. Due to the movement of both particles during this time Tbg, when the white charged particles 30 are located closer to the display surface than the green charged particles 36, white is mixed in the green display, so that a clear display is hindered. Therefore, it is necessary to make the sum of the distances that the green charged particles 36 and the white charged particles 30 move during this Tbg smaller than the distance L between the electrodes. Therefore, L&gt; (Vg + Vw) × tbg, that is, L&gt; (Vg + Vw) x 2R / (Vb-Vg) It is necessary to have the relation of (relationship formula 1).

Relational expression 2: Relational expression when displaying blue Next, "Relationship 2 of the moving speed of charged particles when displaying blue" in a 4-particle system as shown in FIG. 4D will be described. When displaying blue, it is necessary that only the blue charged particles 34 are located closest to the display surface side, and for that purpose, the red charged particles 32 and the blue charged particles 34 are located from the position closest to the display side substrate to the back side. Due to the difference in moving speed (Vr-Vb), the red charged particles 32 need to overtake the blue charged particles 34 by at least one particle 2R when moving to. In other words, if the time required at that time is Trb, then Trb = 2R / (Vr-Vb).

During this time Trb, the blue charged particles 34 (see 4C) that were close to the display side substrate moved to the back side at the moving speed Vb, and the white charged particles were located a predetermined distance Lw from the common electrode 10. 30 (see Fig. 4C) moves to the display surface side at a moving speed of Vw. When the white charged particles 30 are located closer to the display surface than the blue charged particles 34 due to the movement of both particles during this time Trb, white is mixed in the blue display, so that a clear display is hindered. To be more precise, the distance Lw is the distance between the center of the white charged particles 30 and the common electrode 10 minus the radius R of the white charged particles 30.

Here, the distance Lw of the white charged particles 30 from the common electrode 10 as shown in FIG. 4C is obtained as follows. The time Tb (see FIGS. 4A to 4C) when the blue charged particles 34 located near the back substrate move to the display surface side at the moving speed Vb and reach the display surface side substrate close position is Tb = L / Vb. Can be represented. During this time Tb, the white charged particles 30 that were close to the display surface side substrate move to the back side at a moving speed of Vw (see FIGS. 4A to 4C), so that the white charged particles 30 are at the positions shown in FIG. 4C. The distance Lw from the common electrode 10 is Lw = Vw × Tb = Vw × L / Vb.

Therefore, it is necessary to make the sum of the moving distances of the blue charged particles 34 and the white charged particles 30 during the time Trb smaller than the above Lw. Therefore, Lw&gt; (Vb + Vw) × Trb, that is, L&gt; Vb / Vw × (Vb + Vw) × 2R / (Vr-Vb) It is necessary to have the relation of (relationship formula 2).

&lt;In the case of the embodiment of the 5-particle system&gt; Relational expression 3: Relational expression when displaying in black Next, "Relationship formula 3 of the moving speed of charged particles when displaying black" in a 5-particle system as shown in FIG. 5H will be described. When displaying black, it is necessary that only the black charged particles 38 are located closest to the display surface side. For that purpose, the green charged particles 36 and the black charged particles 38 are located from the position closest to the display side substrate to the back surface. When moving to the side, due to the difference in moving speed (Vg-Vbk), the green charged particles 36 need to overtake the black charged particles 38 by at least one particle 2R. In other words, if the time required at that time is Tgbk, Tgbk = 2R / (Vg-Vbk).

During this time Tgbk, the black charged particles 38 (see Fig. 5G) that were close to the display side substrate moved to the back side at a moving speed of Vbk, and the white charged particles 30 that were close to the back surface substrate 30 (see Fig. 5G). ) Moves to the display surface side at the moving speed Vw. Due to the movement of both particles during this time Tgbk, when the white charged particles 30 are located closer to the display surface than the black charged particles 38, white is mixed in the black display, so that a clear display is hindered. Therefore, it is necessary to make the sum of the moving distances of the black charged particles 38 and the white charged particles 30 smaller than the distance L between the electrodes during this Tgbk. Therefore, L&gt; (Vbk + Vw) × tgbk, that is, L&gt; (Vbk + Vw) x 2R / (Vg-Vbk) It is necessary to have the relation of (relationship formula 3).

Relational expression 4: Relational expression when displaying green Next, "Relationship formula 4 of the moving speed of charged particles when displaying green" in a 5-particle system as shown in FIG. 5F will be described. When displaying green, it is necessary that only the green charged particles 36 are located closest to the display surface side, and for that purpose, the blue charged particles 34 and the green charged particles 36 are located from the position closest to the display side substrate to the back side. Due to the difference in moving speed (Vb-Vg), the blue charged particles 34 need to overtake the green charged particles 36 by at least one particle 2R when moving to. In other words, if the time required at that time is Tbg, then Tbg = 2R / (Vb-Vg).

During this time Tbg, the green charged particles 36 (see Fig. 5E) that were close to the display side substrate moved to the back side at a moving speed of Vg, and were white that was a predetermined distance Lw'from the common electrode 10. The charged particles 30 (see FIG. 5E) move toward the display surface at a moving speed of Vw. Due to the movement of both particles during this time Tbg, when the white charged particles 30 are located closer to the display surface than the green charged particles 36, white is mixed in the green display, so that a clear display is hindered. To be more precise, the distance Lw'is the distance between the center of the white charged particles 30 and the common electrode 10 minus the radius R of the white charged particles 30.

Here, the distance Lw'of the white charged particles 30 from the common electrode 10 as shown in FIG. 5E is obtained as follows. The time Tg (see Fig. 5A to Fig. 5E (excluding Fig. 5D)) is the time Tg (see Fig. 5A to Fig. 5E (excluding Fig. 5D)) when the green charged particles 36 that were in the position near the back side substrate move to the display surface side at the moving speed Vg and reach the position near the display surface side substrate. It can be expressed as Tg = L / Vg. During this time Tg, the white charged particles 30 located close to the display surface side substrate move to the back side at a moving speed of Vw (see FIGS. 5A to 5E (excluding FIG. 5D)), and are shown in FIG. 5E. The distance Lw'from the common electrode 10 at the position of the white charged particles 30 is Lw'= Vw × Tg = Vw × L / Vg.

Therefore, it is necessary to make the sum of the moving distances of the green charged particles 36 and the white charged particles 30 between the Tbg smaller than the above Lw'. Therefore, Lw'&gt; (Vg + Vw) × Tbg, that is, L&gt; Vg / Vw × (Vg + Vw) × 2R / (Vb-Vg) It is necessary to have the relation of (relationship formula 4). Even in the embodiment of the 5-particle system, it is necessary to satisfy the above relational expression 2 among the red-charged particles 32, the blue-charged particles 34, and the white-charged particles 30 in order to realize a clear blue display. ..

In the above calculation of the relational expression regarding the moving speed of each charged particle, the case where the particle diameters of the charged particles 30 to 38 are the same has been described as an example, but the present invention is not limited to this, and the particles of each charged particle are not limited to this. Even when the diameters are different, the relational expression regarding the moving speed of the charged particles can be obtained based on the same idea as described above.

(Explanation of Other Embodiments of Particle Mobile Display Device According to the Present Invention&gt; In the above embodiment, the negatively charged white charged particles 30, the positively charged red charged particles 32, the blue charged particles 34, the green charged particles 36, and the black charged particles 38 are used for color display. However, the charging polarity of the charged particles is not limited to this, and the positive and negative can be reversed, and any other color can be used. Further, in the above embodiment, only one type of charged particles (white charged particles in the above) is set as charged particles charged in one polarity (negative electrode in the above), but the present invention is not limited to this. , A plurality of types of charged particles having different colors and moving speeds can be set for each of the positive and negative electrodes.

In the above embodiment, a wet particle moving display device filled with a display medium containing charged particles and a solvent is exemplified, but the present invention is not limited to this, and a dry particle moving display device is used. You can also. This dry particle moving display device can be formed, for example, by enclosing an inert gas in a closed space formed between opposing substrates, and further encapsulating a plurality of types of charged particles. Further, air or nitrogen can be filled instead of the inert gas, the filled gas can be dried and used, or the closed space can be evacuated.

In the case of a dry display device, even after the voltage application is stopped, the moving particles adhere to the substrate in the traveling direction due to the inertial force, or if the inertia is weak, before reaching the substrate. Fall in the direction of gravity. However, since the distribution of charged particles for each type (that is, the order from the transparent substrate) is not changed, a desired color can be displayed. In addition, even when the panel is leaned against the panel, it may be unevenly arranged on one of the partition walls, but even in this case, the order from the transparent substrate is not disturbed, so that the desired color is used. Can be displayed.

In the above embodiment, in order to display the desired color, the applied voltage is turned off when the particle distribution of the desired color is reached, but the present invention is not limited to this, and the particle distribution of the desired color is obtained. When it reaches, it is also possible to apply a braking pulse voltage of a reverse potential for stopping the charged particles. Further, in the case of a system in which the charged particles show some flow immediately after the applied voltage is turned off, it is possible to turn off the applied voltage immediately before the particle distribution of a desired color is obtained in anticipation of this.

Further, the present invention also includes an embodiment of an image display device including the above-mentioned embodiment of the particle mobile display device and a control device for displaying an image on the particle mobile display device. The embodiment of the particle mobile display device according to the present invention and the image display device provided with this display measure is not limited to the above embodiment, and various other embodiments are included in the present invention.

<figref num="1">It is a top view which looked at the particle movement type display device which concerns on this invention from the display surface side.</figref><figref num="2">It is a cross-sectional view seen from the direction of arrow AA of FIG. 1, and is the figure which showed typically the internal structure of the four-particle system display device.</figref><figref num="3">It is a cross-sectional view seen from the direction of arrow AA of FIG. 1, and is the figure which showed typically the internal structure of the 5 particle system display device.</figref><figref num="4A">It is sectional drawing which shows typically the embodiment of the display rewriting in the four-particle system display device which concerns on this invention, and is the figure which shows the case of performing white display.</figref><figref num="4B">It is sectional drawing which shows typically the embodiment of the display rewriting in the four-particle system display device which concerns on this invention, and is the figure which shows the case of performing red display.</figref><figref num="4C">It is sectional drawing which shows typically the embodiment of the display rewriting in the four-particle system display device which concerns on this invention, and is the figure which shows the stage in the process of rewriting before performing the blue display.</figref><figref num="4D">It is sectional drawing which shows typically the embodiment of the display rewriting in the four-particle system display device which concerns on this invention, and is the figure which shows the case of performing the blue display.</figref><figref num="4E">It is sectional drawing which shows typically the embodiment of the display rewriting in the four-particle system display device which concerns on this invention, and is the figure which shows the case of performing black display.</figref><figref num="4F">It is sectional drawing which shows typically the embodiment of the display rewriting in the four-particle system display device which concerns on this invention, and is the figure which shows the case of performing green display.</figref><figref num="5A">It is sectional drawing which shows typically the embodiment of the display rewriting in the 5 particle system display device which concerns on this invention, and is the figure which shows the case of performing white display.</figref><figref num="5B">It is sectional drawing which shows typically the embodiment of the display rewriting in the 5 particle system display device which concerns on this invention, and is the figure which shows the case of performing red display.</figref><figref num="5C">It is sectional drawing which shows typically the embodiment of the display rewriting in the 5 particle system display device which concerns on this invention, and is the figure which shows the stage in the process of rewriting before performing the blue display.</figref><figref num="5D">It is sectional drawing which shows typically the embodiment of the display rewriting in the 5 particle system display device which concerns on this invention, and is the figure which shows the case of performing the blue display.</figref><figref num="5E">It is sectional drawing which shows typically the embodiment of the display rewriting in the 5 particle system display device which concerns on this invention, and is the figure which shows the rewriting stage before performing the green display.</figref><figref num="5F">It is sectional drawing which shows typically the embodiment of the display rewriting in the 5 particle system display device which concerns on this invention, and is the figure which shows the case of performing green display.</figref><figref num="5G">It is sectional drawing which shows typically the embodiment of the display rewriting in the 5 particle system display device which concerns on this invention, and is the figure which shows the case where black display (the 1) is performed.</figref><figref num="5H">It is sectional drawing which shows typically the embodiment of the display rewriting in the 5 particle system display device which concerns on this invention, and is the figure which shows the case where black display (the 2) is performed.</figref>

Code description

2 (Particle mobile) display device 4 Display side board 6 Opposed board 8 bulkhead 10 Common electrodes 12 pixel electrode 14 outer frame 30 white charged particles 32 Red charged particles 34 Blue charged particles 36 green charged particles 38 Black charged particles 40 parcels