JP2002014654A - Image display device and image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image display device and an image forming method capable of obtaining a constant image without burdening a power source with a load. SOLUTION: This display device secures a potential difference |A| V which is large enough to move grains between row electrodes and column electrodes with a driving power source capable of applying the voltage of the order of |A/2| V, for example, by allowing a voltage control part to apply a voltage having A/2 (V) (provided, A is a potential which is irreducibly needed in order to move coloring grains) to row electrodes (for example, display-side electrodes) including an area provided on a display substrate and for moving the coloring grains and to apply a voltage having -A/2 (V) to column electrodes (for example, back-side electrodes 25) including an area provided on a back substrate and for moving the coloring grains.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display apparatus and an image forming method, and more particularly, to a position in which colored particles moving by an electric field are sealed between a pair of substrates arranged opposite to each other, and where the colored particles adhere. The present invention relates to an image display apparatus and an image forming method for displaying an image by using the method.

[0002]

2. Description of the Related Art Conventionally, as a rewriteable sheet-like display medium, Twisting Ball Disp has been known.
For example, a lay (two-color coated particle rotating display medium), an electrophoretic display medium, a magnetophoretic display medium, a thermal rewritable display medium, and a liquid crystal having memory properties have been proposed.

[0003] Among these repeatedly rewritable display media, a thermal rewritable display medium and a liquid crystal having a memory property are characterized by being excellent in an image memory property.

[0004] A display medium utilizing electrophoresis and magnetophoresis disperses colored particles movable by an electric field or a magnetic field in a white liquid, and forms an image with the color of the colored particles and the color of the white liquid. It is. For example, the image portion displays the color of the colored particles by attaching the colored particles to the display surface,
In the non-image portion, the colored particles are removed from the display surface, and white is displayed by the white liquid. In a display medium using electrophoresis and magnetophoresis, since the movement of the colored particles does not occur without the action of an electric field or a magnetic field, the display medium has a display memory property.

[0005] Also, Twisting Ball Dis
In the play, the spherical particles having the half surface painted white and the other surface painted black are reversely driven by the action of an electric field. For example, in the image portion, the black surface is on the display surface side, and in the non-image portion, the white surface is the display surface side. The display is performed by applying an electric field such that

According to this method, the particles do not undergo inversion driving unless there is an action of an electric field. Also, inside the display medium, oil exists only in the cavities around the particles, but since it is almost in a solid state,
It is relatively easy to make the display medium into a sheet.

However, a thermal rewritable display medium, a liquid crystal having a memory function, etc. cannot display a display surface of sufficient white like paper, and when an image is displayed, an image portion and a non-image portion are not displayed. Because the contrast is small,
It is difficult to provide a clear display.

In a display medium utilizing electrophoresis and magnetophoresis, white display is excellent with a white liquid, but when displaying the color of colored particles, the white liquid enters gaps between the colored particles. The concentration will drop. Therefore, the contrast between the image part and the non-image part becomes small, and it is difficult to obtain a clear display.

Further, since a white liquid is sealed in these display media, when the display medium is detached from the image display device and handled roughly like paper, the white liquid may leak from the display medium. There is.

[0010] Twist Ball Displa
In the case of y, even if the hemisphere painted white is completely aligned with the display side, the light rays entering the gap between the spheres are not reflected and are lost inside. Can not. Further, the white display becomes grayish due to the influence of light absorption and light scattering in the cavity portion. Further, it is difficult to completely invert the particles, which also causes a decrease in contrast, and as a result, it is difficult to obtain a clear display. Further, since the particle size is required to be smaller than the pixel size, fine particles having different colors must be manufactured for high-resolution display, which requires advanced manufacturing technology. There is also a problem.

For this reason, several display media using toner (particles) have been proposed as new display media for solving the above problems (Japan Har).
dccopy, '99 Transactions, p249-p252, Ja
Pan Hardcopy, '99 fall Preprints,
p10-p13).

These display media include a transparent display substrate,
Two types of particle groups (toners) having different colors and charging characteristics are sealed between the substrate and a rear substrate opposed with a small gap, and an electric field is applied between these substrates according to image information. By doing so, an image is displayed by attaching particles of any color to the display substrate.

According to the particle display medium using the particle group, the particle group does not move unless an electric field acts, so that the image display medium has a memory property. No liquid leakage problem. Since the display between white and black can be switched by 100% in principle, it is possible to display a clear image with high contrast. Further, a two-color image (for example, a black-and-white image) having a high display contrast can be displayed by using particles having a high concealing property. In the following, a display medium using a particle group is simply referred to as an image display medium.

[0014]

In an image display apparatus using the above-described image display medium, the image quality is determined by the moving state of the particles, and moving the particles stably and instantaneously improves the image quality. It is a big factor to make it happen.

In order to move the particles stably and instantaneously, it is necessary to control three factors: the charge amount of the particles, the adhesive force between the particles and the substrate, and the electric field applied to the space. However, among these three factors, the charge amount of the particles is determined by the material constituting the particles, and the adhesion between the particles and the substrate is determined by the electrical properties of the material constituting the particles and the material constituting the substrate. Therefore, it is difficult to adjust the charge amount of the particles and the adhesive force between the particles and the substrate in the image display medium once manufactured. For this reason, there is a problem that it is difficult to stably and instantaneously move the particles.

In an image display device using an image display medium, a high-contrast image of a reflection type display can be obtained, but the difference is that particles do not move well due to application of a voltage during image formation, that is, There is a problem that an unstable image display is largely affected by the moving state of the particles. In an image display device using liquid crystal, an electric field is constantly applied, so that correction can be easily performed.However, in an image display device using an image display medium that displays an image by adhesion of particles, the image display device is stable within an electric field application time. There is a regulation that it must be configured to enable image output. Further, since the image is displayed by moving the particles, there is a problem that the image display speed is slower than other image display devices such as an image display device using a liquid crystal.

In view of the above, an object of the present invention is to provide an image display device capable of obtaining a stable image without imposing a load on a power supply. Another object of the present invention is to provide an image forming method capable of forming a stable image without imposing a burden on a power supply.

[0018]

According to a first aspect of the present invention, there is provided an image display apparatus comprising: a pair of substrates arranged opposite to each other; A plurality of electrodes arranged so as to face each other, and sealed between the pair of substrates, move between the substrates according to a predetermined potential difference generated between the electrodes arranged facing each other. A colored particle group attached to one of the substrates and, when a predetermined potential difference is generated between electrodes facing each other at a predetermined position among the plurality of electrodes, the polarity of the potential of one of the electrodes facing each other, Display control means for controlling a voltage to be applied such that the polarity of the potential of the other electrode is different,
It has.

According to a tenth aspect of the present invention, a plurality of electrodes provided on each of a pair of opposing substrates have a predetermined potential difference between opposing electrodes at positions corresponding to image information. To form an electric field between the opposing electrodes, and the electric field moves particles sealed between the pair of substrates so that the particles are attached to one of the pair of substrates. An image forming method for forming an image by the color of particles adhered to, when a predetermined potential difference is generated between the opposed electrodes, the polarity of the potential of one of the opposed electrodes, the other The applied voltage is controlled so that the polarity of the potential of the electrode is different from that of the electrode.

In order to obtain stable images by moving particles with a short voltage application time, it is necessary to generate a higher potential difference between the electrodes as compared with a liquid crystal display medium. Therefore, it is necessary to boost the voltage by using a transformer or the like, and an expensive driving device capable of generating such a high potential difference is required.

In the present invention, in order to secure a potential difference required for the movement of the colored particles, the potential applied to the opposing electrodes is made to have the opposite polarity. Can be increased. Therefore, driving with a low potential that does not require boosting by a transformer or the like can be performed. Therefore, image display can be performed well without using an expensive drive device.

The invention described in claim 2 is the first invention.
In the image display device according to the above, the display control means,
It is characterized in that one of the electrodes in an area where particle movement is not required during image formation is grounded.

By grounding one of the electrodes disposed opposite to each other, a potential difference required for the movement of the particles cannot be ensured. Therefore, while the state in which the particles do not move is maintained, electrical control is performed on the electrode to be grounded. No need to do. Therefore, the movement control of the colored particles can be performed only by the driving source of the single potential setting. In addition, the burden on the power supply is reduced,
The voltage control sequence can be simplified.

According to a third aspect of the present invention, there is provided an image display device comprising:
A pair of substrates disposed opposite each other, and at least one of the substrates forming an image display region, and a plurality of electrodes provided on each of the pair of substrates and disposed to face each other in the image display region And a colored particle group that is sealed between the pair of substrates and moves between the substrates according to a predetermined potential difference generated between the electrodes, and adheres to one of the pair of substrates, and is displayed in an image display area. When applying a voltage based on the image information of one frame to generate a predetermined potential difference between the plurality of electrodes, the application of the voltage to the plurality of electrodes based on the same image information of one frame is performed a plurality of times. Display control means for performing repetition.

According to the eleventh aspect of the present invention, there is provided an image processing apparatus, comprising: a plurality of electrodes provided on each of a pair of substrates which are arranged to face each other and at least one of the substrates forms an image display area; A predetermined potential difference is generated between opposing electrodes at positions corresponding to each other to form an electric field between the opposing electrodes, and the electric field moves particles encapsulated between the pair of substrates, thereby causing the pair of substrates to move. An image forming method of forming an image by attaching the particles to one of the substrates and forming the image by the color of the particles attached to the one substrate, wherein the image information is formed based on one frame of image information displayed in the image display area. When the electric field is formed between the opposing electrodes by generating a predetermined potential difference between the opposing electrodes at the position corresponding to the same frame, the same one frame is applied to the opposing electrodes at the position corresponding to the image information. Image of And performing repeated a plurality of times the application of voltage based on the broadcast.

The application of the voltage causes the particles to move and an image is displayed, but it takes a predetermined time for the particles to completely move to the substrate. This time depends on the strength of the electric field formed between the substrates, but the strength of the electric field depends on the potential difference. If the potential difference is too large, a load is imposed on the power supply, which is not preferable. Therefore, in the present invention, when the display control unit applies a voltage based on the image information of one frame displayed in the image display area to generate a predetermined potential difference between the plurality of electrodes, Thus, the application of a voltage based on the same one frame of image information is repeated a plurality of times.

That is, in the present invention, even if the coloring particles are not completely moved to the substrate side by one application of the voltage, the display control means controls the application of the voltage repeatedly so that the coloring particles can be completely removed. To the substrate side. At this time, in the image display area of the board, an image of one frame whose outline is not sufficiently blurred initially appears, and the image is displayed so that the contrast gradually increases and the outline becomes clear. Become. For this reason, even in the image state in which the outline is blurred, the viewer can recognize the image to some extent, and the viewer can recognize the image quickly. This is highly effective, for example, when the image display device of the present invention is used for an advertising signboard or the like.

Further, by repeatedly applying a voltage based on the same one-frame image information a plurality of times, the time required to display a one-frame image is reduced without applying a high voltage. Although this is not clear, when a voltage is applied, a stronger electric field is generated in a region corresponding to the edge portion of the electrode than in a region other than the edge, and it is better to apply such a strong electric field repeatedly. This is presumably because the effect of promoting the movement of the particles is greater than when a long-time voltage is applied or when a high voltage is applied. Therefore, according to the present invention, a stable image can be obtained with a short voltage application time.

According to a fourth aspect of the present invention, there is provided an image display apparatus comprising: a pair of substrates disposed to face each other; and a line shape corresponding to a row or a column of an image in which at least one of the substrates is composed of a plurality of pixels. A plurality of electrodes formed and provided on each of the pair of substrates and opposed to each other, and are sealed between the pair of substrates, and move between the substrates according to a predetermined potential difference generated between the electrodes. A color particle group attached to one of the pair of substrates, and a pixel position of the linear electrode corresponding to a pixel that is connected to the linear electrode and moves a particle from a connection position with the linear electrode. Display control means for applying a correction voltage amount determined according to the distance to the linear electrode to a voltage value determined according to the pixel information.

According to a twelfth aspect of the present invention, there is provided a semiconductor device comprising: a line provided on each of a pair of substrates arranged to face each other, wherein at least one of the lines corresponds to a row or a column of an image composed of a plurality of pixels; Of the plurality of electrodes formed in a shape,
An electric field is formed between the opposing electrodes by generating a predetermined potential difference between the opposing electrodes at positions corresponding to the image information, and the electric field moves particles sealed between the pair of substrates, thereby causing the pair of substrates to move. Attached to one of the substrates,
An image forming method for forming an image based on the color of particles adhered to said one substrate, wherein a pixel position on said linear electrode corresponding to a pixel for moving particles from a voltage application position to said linear electrode A correction voltage amount determined according to the distance to the linear electrode is superimposed on a voltage value determined according to pixel information.

In the present invention, the display control means superimposes and applies a correction voltage to a voltage value determined according to pixel information.

That is, since the electrode itself is also a resistor, when a linear electrode is provided on the substrate, a voltage drop occurs from the position where the voltage is applied to the position where the colored particles are deposited, and the colored particles are removed. In some cases, the voltage at the position where the color particles are attached is insufficient, and an electric field sufficient to move the colored particles cannot be formed. Therefore, the voltage at the position where the colored particles are attached is insufficient, and an electric field sufficient for the movement of the colored particles may not be formed.

This voltage drop increases as the distance from the position where the voltage is applied to the position where the colored particles are attached increases. Therefore, in the present invention, the correction voltage amount for correcting the voltage corresponding to the voltage drop amount that increases according to the distance from the connection position with the linear electrode to the pixel position of the linear electrode corresponding to the pixel for moving the particles. Is superimposed on the voltage value determined according to the pixel information,
An electric field strong enough to move the colored particles can be formed.

In order to superimpose such a correction voltage amount on a voltage value determined according to the pixel information, for example, the display control means may be configured so that the display control means includes The display device may be configured to control the magnitude of the voltage applied to the electrode, or as described in the invention of claim 6, so that the display control means controls the drive time of the voltage applied to the linear electrode. Can be configured.

According to a seventh aspect of the present invention, there is provided an image display apparatus, comprising: a pair of substrates arranged to face each other; and a plurality of electrodes provided on each of the pair of substrates and arranged to face each other. And sealed between the pair of substrates,
Moving between the substrates according to a predetermined potential difference generated between the electrodes, and a group of colored particles attached to one of the pair of substrates, and generating a predetermined potential difference between the plurality of electrodes based on image information. And display control means for applying the same voltage to each of the unit pixels using a predetermined number of electrodes as a unit pixel when displaying an image.

According to a thirteenth aspect of the present invention, of the plurality of electrodes provided on each of the pair of opposing substrates, the predetermined potential difference between the opposing electrodes at a position corresponding to the image information is provided. To form an electric field between the opposing electrodes, and the electric field moves particles sealed between the pair of substrates so that the particles are attached to one of the pair of substrates. An image forming method for forming an image by the color of particles adhered to the unit pixel, wherein when a predetermined potential difference is generated between the opposing electrodes, a predetermined number of electrodes adjacent to each other are set as unit pixels, and The same voltage is applied every time.

In an image display apparatus and an image forming method using an image display medium for displaying an image by using particles, the particles between the substrates adhere to the display substrate while the image display is repeated. There is a drawback that image quality is degraded due to missing pixels of the image.

Therefore, in the present invention, the same voltage is applied to each unit pixel using a predetermined number of electrodes as a unit pixel. By forming one pixel with a predetermined number of electrodes, a plurality of edge portions of the electrode are present in one pixel, so that a plurality of places where a strong electric field is generated in one pixel. In addition, as the unit pixel of the present invention, in addition to the rectangular shape of m rows and n columns, for example, pixels are arranged radially, or pixels are arranged in a honeycomb shape, and a predetermined number is set to one unit. Including cases.

As a result, a plurality of places where a strong electric field is partially formed in one pixel are generated, so that a stronger electric field is generated in one pixel than when one pixel corresponds to one electrode. The colored particles move faster between the substrates,
The display speed of one frame image is increased. Therefore, the voltage application time required for displaying one frame can be reduced, and a stable image can be obtained with a short voltage application time.

Further, in the image display device according to the present invention, there are provided a pair of substrates arranged to face each other, and a plurality of electrodes provided on each of the pair of substrates and arranged to face each other. A colored particle group enclosed between the pair of substrates and moved between the substrates according to a predetermined potential difference generated between the electrodes, and attached to one of the pair of substrates; Each of the electrodes constituting the pixel is configured such that the voltage is applied to each of the unit pixels using the electrodes as unit pixels, and when the density of the adjacent pixels is the same, the arrangement of the colored particles attached in the pixel is different. And display control means for controlling the voltage applied to the display device.

According to the fourteenth aspect of the present invention, a predetermined potential difference is generated between the opposing electrodes at positions corresponding to the image information among the plurality of electrodes provided on each of the pair of opposing substrates. To form an electric field between the opposing electrodes,
By the electric field, the particles sealed between the pair of substrates are moved and attached to one of the pair of substrates, and an image is formed by an image forming method based on the color of the particles attached to the one substrate. A voltage is applied to each of the unit pixels using a predetermined number of electrodes adjacent to each other as a unit pixel, and when the density of the adjacent pixels is the same, the arrangement of the colored particles adhering in the pixel The voltage applied to each of the electrodes constituting the pixel is controlled so as to be different from each other.

In the present invention, a voltage is applied to each unit pixel using a predetermined number of electrodes as a unit pixel, and when the density of adjacent unit pixels is the same, the electrode adheres to the electrode in the pixel. The voltage applied to each electrode constituting the pixel is controlled so that the arrangement of the colored particles is different.

As described above, even if the density is the same, by making the adhesion positions of the colored particles different between the adjacent unit pixels, it becomes difficult to recognize the pixels (dots) constituting the image, thereby improving the image quality. Can be done. Further, even if the densities are the same, since the arrangement is different between adjacent unit pixels, it is difficult for the particles to stay on the same electrode continuously, so that it is possible to prevent the deterioration of the image quality due to the adhesion of the particles.

According to a ninth aspect of the present invention, in the image display device according to the eighth aspect, the display control means displays the pixel having the same density as the previously displayed density when rewriting the image. The voltage applied to each electrode constituting the pixel is controlled so that the arrangement of the colored particles attached to the pixel is different.

As a result, even when the same density is displayed in a specific pixel, the particle does not continuously adhere to the same electrode in the specific pixel, but the color particles can be randomly changed. In addition, it is possible to prevent the image quality from deteriorating due to sticking of particles caused by the particles continuing to adhere to a specific electrode.

[0046]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an example of an embodiment to which an image display medium and an image display device of the present invention are applied will be described in detail with reference to the drawings.

The image display device according to the present embodiment has the structure shown in FIG.
As shown in the figure, the image display unit 10 and the image display unit 10
And a voltage control unit 12 for forming an image on the recording medium.

As shown in FIG. 2, the image display section 10 includes a transparent display substrate 20 forming an image display surface and a back substrate 23.
, The display-side electrode 22, the spacer 26, and the back-side electrode 25 are sequentially formed. The display side electrode 2
A transparent surface coat layer 28 is formed on the surfaces of the second electrode 2 and the back electrode 25, respectively.

The image display device corresponds to the image display device of the present invention, the image display unit 10 corresponds to the image display medium of the present invention, and the display substrate 20 and the rear substrate 23 constituting the image display unit 10 are The display-side electrode 2 corresponds to a pair of substrates of the invention.
2 and the back-side electrode 25 correspond to a plurality of electrodes of the present invention, and the voltage control unit 12 corresponds to a display control means of the present invention.

The display substrate 20 is made of 705 with transparent ITO.
The display-side electrode 22 formed on the display substrate 20 is composed of a plurality of linear ITO electrodes arranged in parallel. Note that, as the display substrate 20, a transparent film or a flexible substrate FPC can be used instead of the glass substrate with the transparent electrode ITO.

The back substrate 23 is formed of a printed wiring board. The printed wiring board is the most versatile member for supplying an electric field, and is suitable because it can be formed into an arbitrary shape by etching a body foil and can be laminated to an epoxy resin to perform wiring to electrodes. .

Of course, the present invention is not limited to a printed wiring board, but may be a member that temporarily stores and holds electric charges, such as a dielectric or a photoconductor using a photoconductive material used in electrophotography. Any member having a function of generating a substrate electric field can be applied.

Further, between the display substrate 20 and the rear substrate 23, two kinds of particles, a first particle 40 and a second particle 42, are sealed. As the first particles 40, for example,
White spherical particles 40 of titanium oxide-containing polymethyl methacrylate having a volume average particle diameter of 20 μm obtained by stirring and mixing fine particles of titania treated with isobutyltrimethoxysilane in white particles at a weight ratio of 100: 0.1 may be used. it can.

As the second particles 42, for example,
Fine particles obtained by treating black particles with silica (A-130 manufactured by Nippon Aloesil Co., Ltd.) with aminopropyltrimethoxysilane are stirred and mixed at a weight ratio of 100: 0.2. Carbon having a volume average particle diameter of 20 μm is obtained. Black spherical powder of the containing crosslinked polymethacrylate (hereinafter, referred to as black spherical particles 42) can be used. The first particles 40 and the second particles 42 correspond to the colored particles of the present invention.

The display-side electrode 22 and the back-side electrode 25 each have a configuration in which linear electrodes are arranged in parallel, and as shown in FIG. 1, have a simple matrix structure in which the extending directions are orthogonal to each other.

The display side electrode 22 and the back side electrode 25
Are connected to the voltage control unit 12, respectively, and the connection with the wiring of the voltage control unit 12 can be performed by, for example, thermocompression bonding with an anisotropic conductive sheet in which conductive particles are embedded. When the display substrate 20 has a large screen and large individual pixels, the display substrate 20 may be directly mounted on the substrate, for example,
The display side electrode 22 of the display substrate 20 and the wiring of the voltage control unit 12 can be electrically connected to each other by applying a conductive paste such as DOTITE (trade name; manufactured by Fujikura Kasei Co., Ltd.) to achieve conduction.

As shown in FIG. 1, the voltage control section 12 comprises an electric field generator 30, a sequencer 32, and a controller (logic IC) 19;
Reference numeral 0 denotes a power supply 34, a waveform generator 36, an amplifier (not shown), and a relay (not shown) or a transistor circuit (not shown). In addition, a relay (not shown) short-circuits all the electrodes connected by the ON signal. Further, the waveform generator 36 generates a waveform determined by a trigger-on signal input from the outside.

In the image display device of this embodiment, the electric field is generated by the electric field generator 30 on each electrode, and the potential of the electrodes is controlled by the sequencer 32 to form one of the display substrate 20 and the rear substrate 23. An electric field corresponding to the image information is simultaneously applied to the formed electrodes in the plane, and an electric field capable of driving the particles in units of one row is applied to the other formed electrodes.

Here, how to apply a voltage to the display side electrode 22 and the back side electrode 25 by the voltage control unit 12 will be described. FIG. 3 shows the relationship between the potential difference between the row and column electrodes and the reflectance of the display surface. As shown in FIG. 3, when a high positive electric field is applied, the black spherical particles 42
0, the reflectance of the display surface of the display substrate 20 decreases, and black display is performed. When a high negative electric field is applied, the white spherical particles 40 move to the display substrate 20, and the reflectance of the display surface of the display substrate 20 increases, and white display is performed. Since similar effects occur when the particles have different charging polarities, an arbitrary color can be displayed by using a combination of particles other than white and black.

As described above, the movement of the particles occurs when a predetermined potential difference exists between the row electrode and the column electrode.
The voltage control unit 12 controls the display-side electrode 2 so that a predetermined potential difference occurs between the display-side electrode 22 and the back-side electrode 25.
A voltage is applied to each of the second and rear electrodes 25.

For example, in a simple matrix structure in which a row electrode is formed on one of a pair of substrates and a column electrode is formed on the other substrate, the potential difference required for moving the colored particles is represented by A.
(Where A = V3-V1) (V), and the potential difference at which the particles do not move is B (where (V3-V1)> B = (V2-V
1)) In the case of (V), in order to obtain the potential difference A necessary for moving the colored particles, the potential of the row electrode and the potential of the column electrode are set to the same polarity as shown in FIG. Applying a voltage of V1 (V) to a row electrode including a region where colored particles are moved, and applying a voltage of V3 (V) to a column electrode including a region where colored particles are moved, or moving the colored particles It is common practice to apply a voltage of V3 (V) to a row electrode including a region and to apply V1 (V) to a column electrode. However, with such a method of multiplying the voltage, in order to secure a necessary potential difference A (V), V
A driving power supply capable of applying a voltage of 3 (V) or more is required, and this voltage value is rather high, which is not preferable.

Further, in the case of such a configuration, it is necessary to always multiply the potential. Alternatively, even if the potential is multiplied only during the movement of the particles, it is necessary to simultaneously write the matrix, and the load on the sequence is large. Further, setting of a high potential via air not only involves a risk of spark discharge but also increases a load on a power source, which is not preferable.

Therefore, in the present embodiment, as shown in FIG. 4B, the voltage control unit 12
A / 2 (V) (however, A / 2 V) is applied to the row electrode (for example, the display-side electrode 22) including the region for moving the colored particles provided in
Applies a voltage of at least a potential difference necessary for moving the colored particles) and applies -A / to the column electrode (for example, the back side electrode 25) provided on the back substrate 23 and including the region for moving the colored particles. 2 (V) voltage is applied.

Thus, even with a drive power supply capable of applying a voltage of about | A / 2 | (V), a potential difference | A | (V) that is large enough to move particles between the row electrode and the column electrode. ) Can be secured.

In the image display device of the present embodiment, when displaying an image, as shown in FIG.
And both the back side electrode 25 are grounded. As a result, the particles remain disposed on either the display substrate 20 side or the rear substrate 23 side and do not move until the next voltage application for image rewriting.

At the time of image rewriting, the voltage control unit 12 applies a voltage to the display side electrode 22 and the back side electrode 25 according to the image information. For example, as shown in FIG. 5B, the voltage control unit 12 applies a voltage of A / 2 (V) to the back electrode 25, and applies the voltage of the display electrode 22 to the electrode corresponding to the region where the particles move. A voltage of -A / 2 (V) is applied, and an area where the particles do not need to be moved is grounded. Thus, A
Only the particles in the space between the rear electrode 25 to which the voltage of / 2 (V) is applied and the display electrode 22 to which the voltage of -A / 2 (V) is applied move. The image is rewritten.

As described above, since the voltage control section 12 only needs to apply a voltage to only the electrodes that need to move the particles, the sequence is facilitated. In addition, since power is not required, there is an advantage that a load on a power supply is reduced.

Further, the image display unit of the present embodiment has a simple matrix structure. However, in order to form an image on the image display unit 10 having such a simple matrix structure, one image is required.
The operation is performed for one frame by generating an electric field corresponding to the column data for each row and driving the particles for each row. In this case, a clear image is displayed on the display surface of the display substrate 20 line by line.

When an image is formed on the image display section of this embodiment by such a method, as shown in FIG. 6, it takes about 10 msec until a good image with sufficient contrast is obtained. Take it.

In the present embodiment, the voltage application time per row is set to 1 msec, and an electric field corresponding to the column data for each row is generated for each row based on the same image data, so that particles are generated for each row. The voltage application process of performing the driving operation for one frame was controlled to be repeated a plurality of times. in this case,
An image for one frame whose outline is blurred is first displayed on the display surface of the display substrate 20, and the image for one frame gradually becomes clear each time the voltage application process is repeated.

As described above, by performing the voltage application processing based on the same image data a plurality of times while shortening the voltage application time, a sufficient contrast can be obtained by the repetition of three times as shown in FIG. Can be. This is presumably because the repeated application of the same voltage promotes the movement of the particles.

Further, in the image display device of the present embodiment,
The operation of applying a voltage to one selected row electrode and all the column electrodes based on the image information of the pixel position where the row electrode and the column electrode overlap each other is performed on the row electrodes formed on the substrate. A voltage is applied so as to sequentially perform one frame image.

At this time, the voltage control unit 12 applies a voltage to each of the row electrode and the column electrode (a power supply position).
Is a specific one of each of the row electrode and the column electrode, and as shown in FIG. 8, as the distance (X) from the power supply position to which the voltage is applied becomes larger, the voltage drop causes the predetermined pixel position to decrease. Is applied by a voltage drop amount C (V),
Will go down.

Therefore, in the image display device of the present embodiment, the voltage control section 12 applies to each electrode a voltage in which the voltage drop C (V) is superimposed as a correction voltage according to the distance from the power supply. ing. Thereby, as shown in FIG. 9, a constant voltage value can be given regardless of the distance (X) from the power supply position to which the voltage is applied, so that the potential difference A between the row electrode and the column electrode can be secured. , Particles can be moved well.

As another method, as shown in FIG. 10, the voltage control section 12 may apply the voltage drop C (V) as a correction voltage to the column electrode according to the distance from the power supply. In addition, the voltage value applied to the other voltage may be corrected so that the potential difference becomes A according to the balance between the voltage drop amount of one of the row electrodes and the column electrode. For example, when the voltage drop amount of the row electrode is h (where h is an arbitrary number) and the voltage drop amount of the column electrode is i (where i is an arbitrary number), (h + i) (V) is corrected. It is preferable to apply a voltage superimposed as a voltage to the column electrode.

By superimposing the correction voltage in this manner,
The display-side electrode 22 and the back-side electrode 2 are made of an electrode material having high resistance.
Even with the configuration 5, it is possible to prevent the potential difference from becoming insufficient due to the voltage drop and hindering the movement of the particles, thereby obtaining a stable image.

Such a correction voltage can be obtained by controlling the drive time (voltage application time), or controlling the magnitude of the voltage. By controlling the driving time (voltage application time), the amount of movement of the particles can be finely adjusted. By controlling the magnitude of the voltage, it is possible to finely adjust the particles that have a large adhesive force and are difficult to move. it can.

When a potential is applied to the electrode, as shown in FIG. 11, the electric field in the region corresponding to the edge of the electrode becomes stronger. Therefore, as shown in FIG. 12, one pixel of the image is constituted by a plurality of electrode units which are divided into, for example, m rows and n columns (where m and n are positive integers), thereby obtaining a pixel shown in FIG.
As shown in (1), by including a region corresponding to the edge of a plurality of electrodes in one pixel, the electric field generated in one pixel can be increased and the particles can be moved quickly. FIG. 12 shows, as an example, four pixels of an image when one pixel of the image is composed of 56 electrode regions, and employs an area-density gradation that represents the density by the area where the particles adhere.

Further, as shown in FIG. 14, when displaying one concentration in a plurality of blocked electrode portions, the electrode positions where the particles are attached are randomly dispersed and arranged, so that the particles are aggregated. Can be prevented, and a good image display state can be maintained. In addition, by randomly dispersing the electrodes to which the particles are attached, it becomes difficult to recognize the dots, so that the image quality can be improved.

Further, FIG. 15 shows the electrode positions to which particles adhere when the plurality of blocked electrode portions display the same density in all four rewrites.
Even in the case of repeatedly displaying pixels of the same density in this way, by changing the arrangement of the electrodes to which the particles are attached,
Since it is possible to avoid particles from continuing to adhere to the same location for a long period of time, it is possible to prevent particles from sticking to the electrode due to long-term adhesion and to prevent deterioration of the quality of a displayed image, which is preferable.

As described above, the present embodiment has a configuration in which the electric field applied to the space for the movement of particles is changed by controlling the applied voltage by the voltage control unit 12 as the display control means for controlling the voltage. A stable image can be obtained with a long voltage application time.

In this embodiment, the case where the present invention is applied to the image display section 10 having a simple matrix structure in which the linear electrodes are arranged so as to be orthogonal to each other has been described. For example, FIG. As shown in FIG. 16B, the present invention can be applied to an image display unit 10 having an active matrix structure in which pixel electrodes are two-dimensionally arranged.

In the above-described embodiment, the case where the image display unit 10 of the image display device has the configuration including the two substrates of the display substrate 20 and the back substrate 23 has been described. The image display unit 10 may include a pair of substrates, such as a two-layer image display unit in which three substrates are opposed to each other, or a three-layer image display unit in which four substrates are opposed to each other. The present invention is also applicable to an image display unit having a multilayer structure.

[0084]

As described above, according to the present invention, there is an effect that a stable image can be obtained without burdening the power supply.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating a schematic configuration of an image display device according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a schematic configuration of an image display unit of the image display device shown in FIG.

FIG. 3 is a graph showing a relationship between a potential difference between a row electrode and a column electrode and a reflectance of a display surface, and an explanatory diagram for explaining an attached state of particles.

FIG. 4A is a graph showing a voltage value required when a voltage having the same polarity is applied between opposing electrodes,
FIG. 4B is a graph showing a voltage value required when voltages of different polarities are applied between opposing electrodes.

FIG. 5A is an explanatory diagram showing an electrode potential and an attached state of particles when an image is displayed, and FIG. 5B is an explanatory diagram showing an electrode potential and an attached state of particles when an image is rewritten. is there.

FIG. 6 is a graph showing a relationship between a voltage application time (drive time) and image contrast.

FIG. 7 is a graph showing the relationship between the number of repetitions and the contrast of an image when the same voltage is repeatedly applied in a short time.

FIG. 8 is a graph showing a row potential with respect to a distance from a power supply.

FIG. 9 is a graph showing a row potential with respect to a distance from a power supply when a correction voltage is superimposed.

FIG. 10 is a graph showing a column potential with respect to a distance from a power supply when a correction voltage is superimposed.

FIG. 11 is an explanatory diagram showing the strength of an electric field in an electrode and a region corresponding to an edge of the electrode.

FIG. 12 is an explanatory diagram illustrating a display state of an image when one pixel of the image is configured by a plurality of electrode units that are divided into, for example, m rows and n columns (where m and n are positive integers). .

FIG. 13 is an explanatory diagram showing the electric field strength in the region corresponding to the electrode and the edge of the electrode in the region where particles are attached by five electrodes in one pixel of FIG. 12;

FIG. 14 shows a block diagram of a plurality of electrode portions,
FIG. 4 is an explanatory diagram showing an electrode position where particles adhere when displaying a concentration.

FIG. 15 shows a graph of 4
FIG. 9 is an explanatory diagram showing electrode positions to which particles adhere when the same density is displayed in all four rewritings.

FIG. 16A is a schematic diagram illustrating the configuration of an image display unit having an active matrix structure, and FIG. 16B is a schematic diagram illustrating the configuration of an image display unit having an active matrix structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Image display part 12 Voltage control part 20 Display board 22 Display side electrode 23 Back substrate 25 Back side electrode 26 Spacer 28 Surface coat layer 30 Electric field generator 32 Sequencer 34 Power supply 36 Waveform generator 40 First particle (white spherical particle) 42 Second particles (black spherical particles)

Continued on the front page (72) Inventor Motohiko Sakamaki 430 Green Tech Nakai, Nakaicho, Ashigara-gun, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (72) Inventor Shota Oba 2274 Hongo, Ebina-shi, Kanagawa Pref. Inventor Nobuyuki Nakayama 430 Green Tech Nakai-cho, Nakai-cho, Ashigarakami-gun, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. 430 Green Tech Nakai, Nakai-cho, Ashigara-gun Fuji Xerox Co., Ltd. F-term (reference) 5C080 AA16 BB05 DD26 DD30 EE26 FF12 JJ02 JJ04 JJ05 JJ06

Claims (14)

[Claims] A pair of substrates disposed to face each other, a plurality of electrodes provided on each of the pair of substrates and disposed so as to face each other, and sealed between the pair of substrates. The colored particles that move between the substrates according to a predetermined potential difference generated between the electrodes disposed opposite to each other and adhere to one of the pair of substrates are opposed to each other at a predetermined position among the plurality of electrodes. Display control means for controlling a voltage applied such that a polarity of a potential of one of the opposed electrodes is different from a polarity of a potential of the other electrode when a predetermined potential difference is generated between the electrodes. An image display device comprising: 2. The image display device according to claim 1, wherein the display control unit grounds one of electrodes in an area where particle movement is not required during image formation. 3. A pair of substrates, which are arranged to face each other, wherein at least one of the substrates forms an image display area, and is provided on each of the pair of substrates, and is arranged to face each other in the image display area. And a plurality of electrodes, while being enclosed between the pair of substrates, a colored particle group that moves between the substrates according to a predetermined potential difference generated between the electrodes, and adheres to one of the pair of substrates, When applying a voltage based on one frame of image information displayed in the image display area to generate a predetermined potential difference between the plurality of electrodes, a voltage based on the same one frame of image information is applied to the plurality of electrodes. And a display control means for repeating the application of a plurality of times. 4. A pair of substrates disposed to face each other, at least one of which is formed in a line shape corresponding to a row or a column of an image composed of a plurality of pixels, and provided on each of the pair of substrates. A plurality of electrodes arranged to face each other, and a colored particle group that is sealed between the pair of substrates and moves between the substrates according to a predetermined potential difference generated between the electrodes, and adheres to one of the pair of substrates. And connected to the linear electrode, the correction voltage amount determined according to the distance from the connection position with the linear electrode to the pixel position of the linear electrode corresponding to the pixel to move the particles A display control unit that superimposes a voltage value determined according to pixel information and applies the voltage value to the linear electrode. 5. The image display device according to claim 4, wherein the display control unit superimposes the correction voltage amount by controlling a magnitude of a voltage applied to the linear electrode. . 6. The image display apparatus according to claim 4, wherein the display control unit superimposes the correction voltage amount by controlling a driving time of a voltage applied to the linear electrode. . 7. A pair of substrates arranged to face each other, a plurality of electrodes provided on each of the pair of substrates, arranged so as to face each other, and sealed between the pair of substrates. It moves between the substrates according to a predetermined potential difference generated between the electrodes, and a group of colored particles adhered to one of the pair of substrates, and generates a predetermined potential difference between the plurality of electrodes based on image information. An image display device comprising: a display control unit configured to apply a same voltage to each unit pixel using a predetermined number of electrodes as a unit pixel when displaying an image. 8. A pair of substrates arranged to face each other, a plurality of electrodes provided on each of the pair of substrates and arranged to face each other, and sealed between the pair of substrates. A colored particle group that moves between the substrates according to a predetermined potential difference generated between the electrodes and adheres to one of the pair of substrates, and sets a voltage for each unit pixel with a predetermined number of electrodes as a unit pixel Display control means for controlling the voltage applied to each electrode constituting the pixel so that the density of adjacent pixels is the same when the density is applied to the adjacent pixels. Image display device provided. 9. The display control unit according to claim 1, wherein when displaying a pixel having the same density as that previously displayed at the time of image rewriting,
9. The image display device according to claim 8, wherein an applied voltage to each electrode constituting the pixel is controlled so that the arrangement of the colored particles attached to the pixel is different. 10. A plurality of electrodes provided on each of a pair of opposing substrates, a predetermined potential difference is generated between opposing electrodes at positions corresponding to image information, and the distance between the opposing electrodes is increased. An electric field is formed, and the particles sealed between the pair of substrates are moved by the electric field to be attached to one of the pair of substrates, and an image is formed by the color of the particles attached to the one substrate. An image forming method for forming, when a predetermined potential difference is generated between the opposed electrodes,
The polarity of the potential of one of the opposed electrodes,
An image forming method, comprising: controlling a voltage applied so that the polarity of the potential of the other electrode is different from that of the other electrode. 11. A plurality of electrodes provided on each of a pair of substrates which are arranged to face each other and at least one of the substrates forms an image display area. An electric field is formed between the opposed electrodes by generating a predetermined potential difference, and the particles sealed between the pair of substrates are moved by the electric field to adhere to one of the pair of substrates, An image forming method for forming an image based on the color of particles attached to one of the substrates, comprising: an inter-electrode located at a position corresponding to the image information based on one frame of image information displayed in the image display area When the electric field is generated between the opposing electrodes by generating a predetermined potential difference between the opposing electrodes at a position corresponding to the image information, a voltage based on the same one frame of image information is applied. Multiple Image forming method, which comprises carrying out repeatedly. 12. A plurality of electrodes provided on each of a pair of substrates arranged to face each other and at least one of which is formed in a line shape corresponding to a row or a column of an image composed of a plurality of pixels. Among them, an electric field is formed between the opposing electrodes by generating a predetermined potential difference between the opposing electrodes at positions corresponding to the image information, and the particles sealed between the pair of substrates are moved by the electric field. An image forming method in which an image is formed by attaching particles to one of a pair of substrates and the color of the particles attached to the one substrate, wherein the particles are moved from a position where a voltage is applied to the linear electrode. Applying a correction voltage amount determined according to a distance to a pixel position on the linear electrode corresponding to a pixel to be superimposed on a voltage value determined according to pixel information to the linear electrode. Special Image forming method according to. 13. A plurality of electrodes provided on each of a pair of opposing substrates, a predetermined potential difference is generated between opposing electrodes at positions corresponding to image information, and the distance between the opposing electrodes is increased. An electric field is formed, and the particles sealed between the pair of substrates are moved by the electric field to be attached to one of the pair of substrates, and an image is formed by the color of the particles attached to the one substrate. An image forming method for forming, when a predetermined potential difference is generated between the opposed electrodes,
An image forming method, wherein a predetermined number of electrodes adjacent to each other are used as unit pixels, and the same voltage is applied to each unit pixel. 14. A plurality of electrodes provided on each of a pair of opposing substrates, a predetermined potential difference is generated between opposing electrodes at positions corresponding to image information, and the distance between the opposing electrodes is increased. An electric field is formed, and the particles sealed between the pair of substrates are moved by the electric field to be attached to one of the pair of substrates, and an image is formed by the color of the particles attached to the one substrate. A method of forming an image, comprising applying a voltage to each unit pixel using a predetermined number of electrodes adjacent to each other as a unit pixel, and adhering to the pixel when the density of the adjacent pixels is the same. Controlling the voltage applied to each of the electrodes constituting the pixel so that the arrangement of the colored particles is different.