JP2003186055A - Electrophoretic display device and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low-cost and high-definition display medium which can change a display color by a simple matrix driving with a simple cell structure. <P>SOLUTION: The manufacturing method for the electrophorestic display device has a plurality of microcapsules 5 each comprising liquid 3 in which a plurality of particles 2 are dispersed and a shell 4 containing the dispersed liquid and 1st and 2nd substrates 6 and 7 where the microcapsules are arrayed in two dimensions and supported, and controls an electric field applied to the respective microcapsules to make the particles electrophoresis. In the method, the microcapsules in coating liquid are precisely arranged at the positions of opening parts by composing of the 1st substrate of a base, a surface layer 10 having the opening parts 10a provided corresponding to the respective microcapsules and a gap layer 9 which is provided between the base and surface layer and make components other than the microcapsules in the coating liquid wherein the microcapsules are dispersed flow. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophoretic display device and a method for manufacturing the same.

[0002]

2. Description of the Related Art Expectations for a reflective display device have been increasing from the viewpoint of reducing power consumption or reducing the burden on the eyes. An electrophoretic display device described in, for example, U.S. Pat. No. 3,668,106 is known as one of the reflective display devices. This electrophoretic display device
As shown in FIG. 15, it comprises a dispersion liquid containing electrophoretic particles A having an electric charge and an insulating liquid B, and a pair of electrodes C and D facing each other with the dispersion liquid interposed therebetween. By applying an electric field to the dispersion liquid, the electrophoretic particles are moved onto an electrode having a polarity opposite to that of the electric charge to perform display. The contrasting color of the electrophoretic particles is carried by the insulating liquid in which the dye is dissolved. More specifically, as shown in FIG. 15A, when the electrophoretic particles A adhere to the surface of the first electrode C near the observer, the color of the electrophoretic particles is observed (particle color display state). ), Meanwhile, FIG.
As shown in 5 (2), when the electrophoretic particles adhere to the surface of the second electrode D far from the observer, the color of the electrophoretic particles is hidden by the insulating liquid and the color of the insulating liquid changes. Observed (background color display state).

Such an electrophoretic device is, for example, a Pro
c. As described in SID, 18, 267 (1977), it has the advantages of a wide viewing angle, high contrast, and low power consumption, but there is no threshold characteristic between the applied voltage and the display color characteristic. Therefore, each pixel electrode must have a switching element, but the required applied voltage is high and the standard thin film transistor (TFT) technology used in liquid crystal displays and the like cannot be used. Furthermore, the use of TFT technology requires a complicated process in a clean environment similar to semiconductor manufacturing.
In addition, if the circuit of the switching element of each pixel is provided on a substrate different from the display panel and the display panel and the substrate are connected by a plurality of wirings, the number of wirings increases in the case where the number of pixels is large, which is not feasible. is there.

On the other hand, with respect to this problem, Proc. SI
D, 18, 255 (1977) and SID 00 DIG
As described in EST, 24 (2000), there is an example in which a simple matrix drive is enabled by devising a cell structure. However, making the cell complicated leads to an increase in the cost of the display device without utilizing the features of the simple electrophoretic display device. Further, making the cell complicated also hinders an increase in resolution. In the above structure for driving a simple matrix, a partition for providing a control electrode is present in the cell. Even if the resolution of the display device becomes higher and the cell becomes smaller, the size of the partition wall cannot be made smaller, resulting in a reduction in the aperture ratio and deterioration of the display characteristics.

In view of the above problems, the present inventors have developed an electrophoretic display device that realizes simple matrix driving with a simple structure, and have already applied for a patent (Japanese Patent Application No. 2001).
-316760: unpublished). The display operation will be described with reference to FIG. In this electrophoretic display device, a microcapsule 5 containing a dispersion liquid 3 containing an insulating liquid 1 and a plurality of electrophoretic particles 2 in a shell 4 between a first substrate 6 and a second substrate 7. Are arranged. First substrate 6
On the surface of the dispersion liquid side, protruding first electrodes 11a and second electrodes 11b are alternately formed in parallel between the microcapsules. By making the shape of the first and second electrodes projecting, the positional accuracy of the microcapsules 5 and the first and second electrodes can be improved. Can be formed into a triangular or trapezoidal shape having a height of about 10 to 20 μm by screen printing or gravure printing technology. On the dispersion liquid side surface of the second substrate 7, the first and second electrodes 11a and 11b are formed.
A transparent third electrode 12 intersecting with is provided. The first to third electrodes 11a, 11b, 12 are connected to a power source 14, and a desired electric field is formed inside the microcapsule 5 under the control of the power source 14 to cause the electrophoretic particles 2 to move to a third position. Electrode 12 side, first electrode 1
Electrophoresis on the 1a side or the second electrode 11b side,
The display color of each microcapsule 5 is controlled.

In the aforementioned electrophoretic display device for which the present inventors have applied for a patent, the dispersion liquid is contained in microcapsules, and the microcapsules and the driving electrodes are printed on a predetermined substrate to be manufactured. However, although it is effective from the manufacturing process, how to properly arrange the microcapsules at a predetermined position on the drive electrode greatly affects the display characteristics.

Further, in such an electrophoretic display device, the display color displayed by a single cell (microcapsule) is two colors, that is, the color of the insulating liquid and the color of the particles dispersed in the liquid. Is limited to. Therefore, in order to display a plurality of colors, it is necessary to arrange a plurality of cells having different colors in a dot matrix to perform a color display, which complicates the manufacturing process and complicates the driving circuit.
It was not suitable for a simple device.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to solve the problems of the prior art. That is, in an electrophoretic display device having a high resolution and a large number of pixels, it is difficult to use a standard thin film transistor technology used in a liquid crystal display or the like because the voltage for moving electrophoretic particles is high. Further, manufacturing a thin film transistor requires a complicated process and a clean environment similar to those of a semiconductor. On the other hand, although simple matrix driving in an electrophoretic display device has been proposed, the cell structure becomes complicated. The complicated cell leads to an increase in the cost of the display device and cannot utilize the feature of the electrophoretic display device having a simple structure. The purpose of the present invention is to
It is an object of the present invention to provide an electrophoretic display device having a simple cell structure and a background color that can be changed. Another object of the present invention is to provide an excellent manufacturing method capable of accurately arranging cells.

[0009]

A first aspect of the present invention provides a plurality of microcapsules consisting of a dispersion liquid in which a plurality of electrophoretic particles are dispersed in an insulating liquid and a shell containing the dispersion liquid.
The microcapsules are arranged and held two-dimensionally, and the first and second substrates provided with electrodes for applying an electric field to the microcapsules are provided. In the electrophoretic display device in which the electrophoretic particles contained in the microcapsules are electrophoresed under control, the first substrate is
A substrate body, and a surface layer having a space between the substrate body and an opening penetrating the space corresponding to the position where each of the microcapsules is arranged; An electrophoretic display device comprising:

In the first aspect of the present invention, the background color can be changed by providing a means for injecting and discharging a liquid such as a coloring liquid in the void layer, which is connected to the void layer.

The second aspect of the present invention is a two-dimensional two-dimensional microcapsule including a plurality of microcapsules each comprising a dispersion liquid in which a plurality of electrophoretic particles are dispersed in an insulating liquid and a shell containing the dispersion liquid. First and second substrates provided with electrodes for arraying and holding and for applying an electric field to the microcapsules, and controlling the electric field applied to each of the microcapsules, In the method of manufacturing an electrophoretic display device in which the electrophoretic particles contained therein are electrophoresed, the first substrate is disposed with a space between the substrate body and the substrate body, and A surface layer having openings penetrating the voids corresponding to the positions where the microcapsules are provided on the surface of the first substrate. It is characterized in that the dispersed coating liquid is applied, and the liquid components in the coating liquid are caused to flow out from the openings and the voids connected to the openings to arrange the microcapsules in correspondence with the openings. It is a method of manufacturing an electrophoretic display device.

In the second aspect of the present invention, the void layer has a structure in which an arbitrary space is held between the support and the surface layer. Further, the void layer may have a groove-shaped structure. Further, the void layer may have a structure in which spaces are formed between the support and the surface layer by partition walls or spacers. Further, the void layer may have a porous structure. The size of the opening is 10
It may have a structure of not more than μm. Further, the openings may be arranged in a matrix, and the contour shape may have a structure of a circle, a regular triangle, a square, a rectangle, or a regular hexagon in a plan view. Further, this opening may be configured by arranging small holes so as to have a required opening area. This makes it possible to prevent the microcapsules from flowing out of the openings when the microcapsules are placed at the predetermined positions.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The electrophoretic display device of the present invention will be specifically described below with reference to the drawings. FIG. 1 is a schematic sectional view of an electrophoretic display device of the present invention, showing a sectional configuration diagram of one pixel portion. In this electrophoretic display device, a microcapsule 5 is arranged between a pair of substrates (first substrate 6 and second substrate 7) having electrodes 11a, 11b and 12 for applying an electric field. Electrodes 11a, 11b, 1
2 is connected to the power supply 14 by electric wirings 15a, 15b, and 15c so that different potentials can be applied to each, and the magnitude and polarity of the applied voltage can be freely set. Further, in the case of the electrophoretic display device having the configuration shown in FIG. 1, an observer looks at the display device from the outside of the second substrate 7 toward the first substrate 6.

In the microcapsule 5, a dispersion liquid 3 in which positively or negatively charged electrophoretic particles 2 are dispersed in an insulating liquid 1 such as isoparaffin is used as a hydrophilic transparent polymer such as gelatin-arabic gum. The electrophoretic particles 2 are sealed by using a shell 4 formed of a film or the like, and it is possible to appropriately select a combination of the materials so that the electrophoretic particles 2 will not dissolve or swell depending on the insulating liquid 1. preferable. The electrophoretic particles 2 are made of black resin toner,
It is a chargeable particle such as an organic or inorganic colored pigment, and the visibility of the display can be improved by coloring it with a color different from that of the insulating liquid 1 or the coloring layer 8 described later. The average particle size of the electrophoretic particles is 0.1 to 5
The range is preferably μm, more preferably 1 μm.

The first substrate 6 is provided with a colored layer 8 formed on one surface of a substrate body 6a formed of a transparent glass plate or a transparent plastic plate, and the colored layer 8 provided so as to face the colored layer 8. A surface layer 10 formed of transparent glass or the like,
The void layer 9 formed between the colored layer 8 and the surface layer 10.
Is equipped with. Then, as shown in FIG. 2, on the surface of the surface layer 10, the first electrodes 11a and the second electrodes 11b extend in one direction of the plurality of microcapsules 5 arranged in a two-dimensional manner and have a predetermined interval. Is formed by. These electrodes are formed of transparent electrodes such as ITO. Also,
At a predetermined position of the surface layer 10, an opening 10a is formed which connects the surface of the first substrate facing the microcapsule 5 and the void layer 9.

The colored layer 8 is formed by spin coating or the like in which fine powder such as barium sulfate, calcium carbonate, silicon dioxide or titanium dioxide and resin such as fluororesin are dispersed / dissolved in a solvent. The thickness is preferably about 0.5 μm. This first
In the substrate 6, the colored layer 8 can be omitted when the insulating liquid 1 is opaque.

The opening 10a is for letting out the liquid component of the coating liquid in which the microcapsules 5 are dispersed when the microcapsules 5 are aligned and arranged on the first substrate 6, and its diameter is The diameter of the microcapsules 5 needs to be smaller than that of the microcapsules 5 so that the microcapsules 5 do not flow out together with the liquid component. The opening 10a may have a circular shape, or may have a slit shape as shown in FIGS. 13 (1), (2), and (3). With such a slit shape, the area of the opening can be increased without fear of the microcapsule 5 flowing out, and the time of the step of forming the microcapsule layer can be shortened, which is preferable. Also, FIG.
3 (4), the opening end of the opening 10a may be chamfered to form a tapered shape. by this,
This is preferable because there is no risk of the microcapsules 5 being broken by the open ends of the openings. Further, the opening 10a
The inner surface of the can be subjected to a hydrophilic treatment. This makes it possible to further reduce the possibility of breaking the microcapsules 5.

The void layer 9 may be formed over the entire surface of the electrophoretic display device of the present invention, or may be a groove formed in the surface layer 10 or the first substrate body 6a. Good. Further, the void layer 9 may be a porous body having pores communicating with each other, not just a gap formed by the substrate body 6a or the colored layer 8 and the surface layer 10. In any case, this void layer 9
When assembling the electrophoretic display device of the present invention, the liquid component in which the microcapsules as the coating liquid are dispersed is discharged to the outside of the system, or the coloring liquid is used to change the background color of the electrophoretic display device. It is configured to be able to inject and discharge. For that purpose, it is preferable to be able to connect to a liquid injection / drainage means such as a pump.

On the other hand, the second substrate 7 which constitutes the viewer-side surface of the electrophoretic display device of the present invention is one in which the transparent electrode 12 is formed on the surface of the substrate body 7a such as transparent glass. As shown in FIG. 2, the transparent electrode 12 is patterned and formed so as to be substantially orthogonal to the first electrode 11a and the second electrode 11b.

FIG. 2 is a block diagram of the main part of the electrophoretic display device shown in FIG. 1 viewed from the second substrate 7 side. In FIG. 2, FIG. 1 is a view of a cross section taken along the line AA ′ in the arrow direction. The first electrode 11a and the second
The electrodes 11b are alternately arranged at a predetermined interval in parallel in the vertical direction of the paper surface, the microcapsules 5 have substantially the same size, and two-dimensional printing is performed so that each center is the center of the opening 10a. It is aligned by the means of. In this figure, in the void layer 9, grooves are arranged in parallel in the left-right direction on the paper at a predetermined interval, and 2 × 2 in which one pixel is surrounded by a thick frame 16
4 microcapsules, and the third electrode 12 is formed on the second substrate 7 correspondingly.

Although not shown in FIGS. 1 and 2, a means such as a pump for injecting or discharging the liquid into the void layer may be connected to the void layer 9. When the insulating liquid 1 is a transparent solution, the background color can be made the hue of the coloring liquid by injecting the coloring liquid into the void layer 9 using this means. When the colored liquid in the void layer 9 is opaque, the color of the colored liquid is visible to an observer, while when the colored liquid is transparent, the color of the colored liquid and the colored layer 8 are A subtractive mixed color of the colors is visually recognized.

The operating principle of the electrophoretic display device will be described below with reference to FIG. 3, which is a schematic diagram showing the operation of the electrophoretic display device of the present invention. In this description, it is assumed that the electrophoretic particles are positively charged. Also,
The potentials applied to the first electrode are 0V, 25V and 50V.
Three stages of V, the potential applied to the second electrode is a fixed potential of 15 V, and the potential applied to the third electrode is 0.
The display operation of the electrophoretic display element can be controlled by setting the potentials in three stages of V, 15V, and 30V and controlling these potentials. It should be noted that these potentials are not limited to this value, and can be set appropriately in consideration of materials used and the like. First, at the initial stage of driving the electrophoretic display device of the present invention, the first electrode is set to 0.
V, 15 V is applied to the second electrode, and 15 V is applied to the third electrode, and the electrophoretic particles 2 are collected on the first electrode 11a and rewritten as shown in FIG. This voltage setting is kept until the timing comes, and the electrophoretic particles 2
Are held on the first electrode 11a. When the rewriting timing comes and the first electrode 11a is boosted to 25V, the electrophoretic particles 2 move in different directions depending on the voltage value of the third electrode 12. That is, the third electrode 12
When the potential of the electrode is 30V, the electrophoretic particles 2 are directed toward the second electrode 11b as shown in (2) -a of FIG. 3, and when the potential of the third electrode 12 is 0V, (2) of FIG. It goes toward the 3rd electrode 12 like -b. Then, while the electrophoretic particles 2 are moving to a desired position, the potential of the first electrode 11a can be raised to 50 V to accelerate the moving speed of the electrophoretic particles 2. In the pixels in the column that has been rewritten,
The voltage of the first electrode 11a is kept at 50V, but the potential of the third electrode 12 becomes a different potential of 30V or 0V when rewriting another pixel column. At that time, the electrophoretic particles 2 move to some extent due to changes in these potentials, as shown in (3) -a and (3) -b of FIG. However, after rewriting the other pixel columns, the third electrode 12 is
When the electrophoretic particles 2 are maintained at V, the electrophoretic particles 2 are (4) -a in FIG.
And (4) -b returns to the desired position.

After the rewriting of all pixel columns is completed, each electrode has 50 V for the first electrode and 15 V for the second electrode.
By applying a voltage of V and 15 V to the third electrode, the electrophoretic particles 2 are attached to the third electrode 12 or the second electrode 11b, and the rewriting operation of the pixel is completed. By doing so, the electrophoretic particles 2 reciprocate between a desired position and an intermediate position while the entire screen is being rewritten, and the electrophoretic particles 2 should be stably positioned at the desired position after rewriting the entire screen. become. During rewriting, the electrophoretic particles 2 are moving, so the image is not stable and becomes a blurred image, but it is intended to display a still image such as an advertisement display board or electronic paper. There is no particular hindrance to the display device.

In addition, the electrophoretic particles 2 are connected to the second electrode 11b.
When collected, the observer sees the colored liquid in the colored layer 8 or the void layer 9 or a mixed color thereof. With the structure shown in FIG. 1, the electricity on the second electrode 11b is changed. The electrophoretic particles 2 are also visible, and the color mixture of the colored layer 8 and the electrophoretic particles 2 is seen. To prevent this, the second
A shielding layer (not shown) that shields the electrophoretic particles 2 on the second electrode 11b may be provided on the surface of the substrate 7.

(Driving Operation of Electrophoretic Display Device) The driving operation of the electrophoretic display device will be described in more detail below. FIG. 4 shows the second electrophoretic display device shown in FIG.
In the view seen from the substrate 7 side, the pixel structure is set to 8 × 8 pixels in order to simplify the description. The third electrode 12 extends leftward and rightward on the paper surface of the first electrode 11a and the second electrode 1
1b extends in the vertical direction on the paper surface. The portion B surrounded by a bold line in FIG. 4 corresponds to one pixel, and as described above, 2 ×
It is composed of 4 microcapsules of 2. A voltage is applied to the eight first electrodes 11a by the driver 14-1 of the power supply circuit, and the same voltage is always applied to all electrodes of the second electrode 11b by the driver 14-2 of the power supply circuit. The voltage of the eight third electrodes 12 is controlled by the driver 14-3 of the power supply circuit. And
First electrode 11a, second electrode 11b, third electrode 12
The magnitude and timing of the voltage to the power supply circuit are controlled by the controller 14-4 of the power supply circuit.

When the screen of the display device is rewritten, a plurality of pixels in the column of the first electrodes 11a-1 are sequentially arranged from the left in FIG.
Rewriting is performed in the order of a plurality of pixels in the first electrode 11a-2 column. FIG. 5 shows the first electrode 11a and the third electrode 1
2 shows a method of applying a voltage to No. 2. First, as the first operation, as shown in the timing (S) of FIG.
0 V, the third electrode 12 of 15 V, and the second electrode 11 b of 15 V are applied to the electrode 11a. Then, the electrophoretic particles 2 gather on the first electrode 11a having a low electric potential. It will be rewritten according to the data to be displayed next. Timings (1) to (8) in FIG. 5 are timings at which the eight pixel columns in FIG. 5 are sequentially rewritten from the left. The voltage of the first electrode shown in FIG. 5 indicates the voltage of the electrode 11a-2 corresponding to, for example, the second pixel column from the left in FIG.
Further, the voltage to the third electrode shown in FIG. 5 indicates one of the eight third electrodes shown in FIG. Until each pixel row is rewritten,
The potential of the first electrode is set to 0 V, and the electrophoretic particles 2 are set to the first position.
Hold it on the electrode. Then, when it comes to the rewriting order of the corresponding pixel column, the potential of the first electrode is raised to 25V. At this time, the potential of the third electrode 12 is 0 V when displaying black and 30 V when displaying white. Then, in the column for which rewriting is completed, the value of the first electrode is raised to 50V.

In the cell in the column whose display has been rewritten,
As shown in Fig. 5, the voltage of the first electrode is 50V,
The voltage on the third electrode is zero due to the signals to the pixels in the other columns.
It becomes V or 30V. At this time, as shown in FIG.
The voltage to the electrodes of the
Provide a time for 5V. In this embodiment, the time for 0V or 30V is 10 msec, and the time for 15V is 10 msec. By doing so, during the first 10 msec, the electrophoretic particles 2 slightly move in a direction different from the desired position depending on the voltage value of the third electrode, but during the next 10 msec. Then it returns to the desired position again. In this way, in the cell after rewriting, the electrophoretic particles 2 reciprocate near the desired position, but eventually return to the desired position.

Then, as the final operation of screen rewriting,
By keeping the state of 50 V for the first electrode, 15 V for the third electrode, and 15 V for the second electrode for a certain time, the electrophoretic particles 2
Settles on the electrode at the desired location. In this embodiment, this holding time is 100 msec. Even if the voltage of each electrode is set to 0 V after rewriting, the electrophoretic particles 2 are held on the electrodes and the screen information can be maintained, as in the conventional electrophoretic display device.

[Method of Manufacturing Electrophoretic Device] The method of manufacturing the electrophoretic display device of the present invention will be described below. The electrophoretic display device of the invention can be manufactured by the steps of manufacturing a substrate, manufacturing microcapsules, forming microcapsule layers, and assembling the device.

(Production of Substrate) The first substrate 6 of the electrophoretic display device of the present invention is the first substrate body 6 as described above.
a, surface layer 10, electrode 11 formed on surface layer 10
a, 11b, and a colored layer 8 formed on the surface of the first substrate body if desired, and a void layer 9 is formed between the substrate body 6a or the colored layer 8 and the surface layer 10. Electrodes 11a formed on the surface of the surface layer 10,
11b can be easily formed by patterning a transparent film formed by a method such as vapor deposition. In addition, the opening 10a formed in a required portion of the surface layer 10
Can be formed by laser processing. Further, the void layer 9 formed between the surface layer 10 and the substrate body 6a or the colored layer 8 is formed by laser processing the substrate body 6a or the surface layer 10 when formed in a groove shape. can do. In addition, this void layer 9
In the case where the substrate body 6a and the surface layer 10 are formed by a gap, the substrate body 6a and the surface layer 10 can be formed by adhering the substrate body 6a and the surface layer 10 via a spacer having an appropriate thickness. . Further, as the void layer 9,
To adopt a porous body, it can be formed by providing a porous aluminum oxide layer on the surface of the substrate body 6a or the surface layer 10 by electroless plating, or a sintered porous ceramic plate. It can also be formed by producing and laminating a porous plate-like body such as. Further, the colored layer 8 can be formed by applying a coating material formed by dispersing a pigment in a binder and a solvent by a method such as spin coating. Any of these methods can employ a conventional means.

The second substrate 7 comprises a substrate body 7a and a third electrode 12 formed on the surface of the substrate body 7a.
Similarly to the first and second electrodes described above, the electrode 12 can be easily manufactured by patterning the transparent electrode film.

(Production of Microcapsules) Microcapsulation techniques include coacervation method, interfacial polymerization method, in situ polymerization method, in-liquid curing coating method, phase separation method from organic solution system, melt dispersion cooling method, gas There are a medium suspension method, a spray drying method, and the like, which can be appropriately selected depending on the use and form of the display medium. The coating of the microcapsules has hydrophilic properties, and in addition to gelatin-arabic gum, condensation type polymers such as melanin resin, epoxy resin, urea resin, phenol resin, furan resin,
A thermosetting resin such as a three-dimensional crosslinked vinyl polymer such as a styrene-divinylbenzene copolymer or a methyl methacrylate-vinyl acrylate copolymer can be appropriately used. Moreover, you may form the multilayer coating film which comprises a microcapsule using 2 or more types selected from the above-mentioned thermosetting resin and thermoplastic resin. In this case, from the viewpoint of improving the thermal stability of the microcapsules, it is desirable to use a thermosetting resin for the outermost shell of the coating.

(Formation of Microcapsule Layer) In the present invention, in order to align the microcapsules 5 containing the electrophoretic particles 2 in the gap formed by the first substrate 6 and the second substrate 7, the openings are formed. A coating liquid consisting of a binder resin solution in which microcapsules 5 are dispersed is applied to the surface of the first substrate 6 having the surface layer 10 on which the microcapsules 10 are formed, and the solvent in which the microcapsules are dispersed flows out from the opening 10a. Or the opening 10a as described above.
From the void layer 9 connected to the substrate 1, the pressure is reduced by a means such as a pump, or the second substrate 7 is placed on the upper surface of the first substrate 6 coated with the coating liquid in which the microcapsules 5 are dispersed. By applying pressure, the solvent of the microcapsule dispersion liquid is caused to flow out from the opening 10a of the first substrate,
Depending on the pressure of the solvent flowing out at that time, the microcapsules 5
Are aligned just above the opening 10a. In the present invention, it is preferable to use a water-soluble resin such as a water-soluble polyamide resin as the binder resin, and water is preferable as the solvent that dissolves the binder resin.

(Assembly of Electrophoretic Display Device) According to the above method, the first substrate 6 and the second substrate 7 on which the microcapsules 5 are aligned are fixed to each other with an adhesive or the like, and , The first electrode 11a, the second electrode 11
The required wiring is formed from b and the third electrode 12,
The electrophoretic display device of the present invention can be assembled.

[0035]

EXAMPLES The present invention will be described in detail below with reference to examples. (Example 1) In an electrophoretic display device having a structure similar to that shown in Fig. 1, selection, formation, and setting of each member were performed as follows. That is, as the first and second substrate bodies 6a and 7a, transparent glass plates with a thickness of 1 mm were used. The first substrate 6 was manufactured by the following method. First, on a transparent glass having a thickness of 1 mm, a coloring layer 8 having a thickness of about 0.5 μm was formed by spin coating a mixture of fine powder of barium sulfate, calcium carbonate, silicon dioxide, titanium dioxide and the like in a fluororesin. next,
A photosensitive glass was used as the surface layer 10, and a groove-shaped void layer 9 and an opening 10a were formed in this by patterning. The void layer 9 and the opening 10a are connected to each other. Further, the glass plate provided with the colored layer 8 was bonded with a UV curable resin. ITO is vapor-deposited thereon with a thickness of about 0.5 μm to form the first and second electrodes 11a, 1
The 1st board | substrate 6 was produced by forming 1b. Also the third
The electrode 12 is made of transparent ITO on the second substrate 7 with a thickness of about 0.
It was prepared by vapor deposition to 1 μm. In this example, the resolution of the display device was set to about 300 dpi, the distance between the centers of the first and second electrodes was set to 40 μm, and the microcapsule particle size was set to 40 μm. As described above, the size in which two microcapsules are arranged vertically and two horizontally is one pixel.

The microcapsules 5 were prepared by the coacervation method. First, black resin toner (particle size 1 μm) was used as the electrophoretic particles 2, and isoparaffin was used as the insulating liquid, and both were mixed so that the mixing weight ratio of the electrophoretic particles 2 was 10%, and the dispersion stability was further improved. A dispersion liquid 3 was prepared by adding a small amount of a surfactant to improve the dispersion. In this case, the surface of the electrophoretic particles 2 was positively charged. Next, 11 parts by weight of the dispersion liquid 3 was emulsified with 100 parts by weight of pure water and 2 parts by weight of an emulsifier with a homogenizer.
This emulsified mixed solution was added dropwise to a 5% gelatin-arabic gum aqueous solution at 40 ° C., and 10% acetic acid was added dropwise with stirring to adjust the pH to 3.5. After that, the temperature is 5 ℃
Down to 37% formalin and add 10% N
Aqueous aOH solution was added dropwise to adjust the pH to 8.5, and the temperature was raised to 50 ° C. to cure the film. Then, wash with pure water and
After that, the microcapsules having an average particle size of 40 μm and contained in the transparent polymer film having hydrophilic property were obtained.

Microcapsules 5 prepared by the above method
Water was mixed with water and a water-soluble polyamide as a binder resin to form an ink, and a microcapsule ink as a coating liquid in which the microcapsules 5 were dispersed was prepared. Then, this was printed on the first substrate 6 through a screen plate in which predetermined openings were two-dimensionally perforated.

FIG. 6 is a conceptual diagram of the printing process of the microcapsule ink in the method for manufacturing an electrophoretic display device of the present invention. The process of forming the microcapsule layer of the present invention will be described with reference to FIG. That is, FIG. 6 (1)
As shown in FIG. 6, a first substrate 6 is prepared, and a microcapsule ink, which is a coating liquid in which the microcapsules 5 are dispersed, is applied on the surface on the side where the microcapsule layer is formed by printing (FIG. 6 (2)). After that, the liquid component in which the microcapsules 5 are dispersed, that is, the binder resin and the solvent,
It flows out to the void layer 9 through the opening 10a. At that time, the microcapsule 5 is attracted to the opening 10a by the fluid pressure when the liquid component forming the microcapsule ink is discharged to the void layer 9 through the opening, and finally the microcapsule 5 is opened. It comes to be located at the center of the portion 10a (FIG. 6 (3)). Then, the second substrate 7
However, when the second capsule is covered with the microcapsule coating layer and pressed against the first substrate 6 side by the weight of the second substrate or the external pressure, the residual liquid component in the microcapsule ink is further discharged from the opening 10a. Finally, the microcapsules 5 themselves are also deformed into a shape suitable for a single cell for display (FIG. 6 (5)). Further, the binder resin forming the microcapsule coating liquid has a function of adhering these microcapsules 5 to the first substrate and the second substrate. Even when the microcapsule cannot be arranged at a desired position during printing, the solvent component other than the microcapsule in the microcapsule ink is moved from the opening 10a to the void layer 9, so that the microcapsule is opened. Attracted to 10a (suction)
I was able to position it precisely at the pinpoint position.

Next, the second substrate 7 on which the third electrode 12 is formed is made of a thermosetting resin, an ultraviolet curing resin or the like, and the third electrode 12 and the microcapsule 5 are shown in FIG. An electrophoretic display panel was manufactured by adjusting and adhering it to the position.

(Example 2) In Example 1 described above, the opening and the groove-shaped void layer were formed of photosensitive glass. However, the void layer retained a space between the support and the surface layer with a spacer. It can be made into a structure. In the electrophoretic display device shown in FIG. 7, each member was selected, formed, and set as follows. First and second substrate body 6
A transparent glass plate with a thickness of 1 mm was used as a and 7a. The first substrate 6 was manufactured by the following method. First, as shown in FIG. 8, a layer having a thickness of about 0.5 μm was formed as a colored layer 8 on a transparent glass plate in the same manner as in Example 1. Next, the surface layer 10 provided with the opening 10a was formed by patterning using photosensitive glass. I on it
The first and second electrodes 1 are formed by depositing TO with a thickness of about 0.5 μm.
1a and 11b were formed. Further, the glass plate provided with the colored layer 8 was used as a spacer 13 by potting a UV curable resin so as to have a uniform thickness, and bonding the UV curable resin to each other to manufacture the first substrate 6. The third electrode 12 was formed by depositing transparent ITO on the second substrate 7 to a thickness of about 0.1 μm.

The microcapsule 5 is the same as in the second embodiment.
It was created by the coacervation method in the same manner as. The microcapsules 5 prepared by the above method are mixed with water and a water-soluble polyamide as a binder resin to form an ink, and the microcapsule ink is printed on the first substrate 6 through a screen plate in which predetermined openings are two-dimensionally perforated. did. FIG. 9 shows a conceptual diagram of the printing process of the microcapsule ink. Even when the microcapsule cannot be arranged at a desired position during printing, the solvent component in the microcapsule ink moves from the opening 10a to the void layer 9 to attract the microcapsule to the opening 10a ( I was able to suction it) and position it precisely at the pinpoint position. Next, the electrophoretic display device panel was manufactured by adjusting and adhering the above-mentioned second substrate 7 on which the third electrode 12 is formed with a thermosetting resin or an ultraviolet curable resin.

(Third Embodiment) In the first embodiment, the opening and the groove-shaped void layer are made of the photosensitive glass, but they may be made of a porous material. The first substrate 6 was manufactured by the following method. First, as shown in FIG. 10, a transparent plastic substrate having a thickness of 1 mm was used as the first substrate body 6a. First, a layer having a thickness of about 0.5 μm was formed as a colored layer 8 on a transparent plastic substrate in the same manner as in Example 1. Next, the void layer 9 is formed by electroless plating using aluminum oxide as the porous material.
Was formed. Next, the surface layer 1 is coated with a polyimide resin.
After forming 0, ITO was vapor-deposited to a thickness of about 0.5 μm to form the first and second electrodes 11a and 11b. Next, the opening 10a was formed by die molding to fabricate the first substrate 6. The third electrode 12 was formed by depositing transparent ITO to a thickness of about 0.1 μm on the second substrate 7 using a transparent plastic substrate having a thickness of 1 mm.

The microcapsule 5 is the same as in the second embodiment.
It was created by the coacervation method in the same manner as. The microcapsules 5 prepared by the above method are mixed with water and a water-soluble polyamide as a binder resin to form an ink, and the microcapsule ink is printed on the first substrate 6 through a screen plate in which predetermined openings are two-dimensionally perforated. To do. FIG. 11 shows a conceptual diagram of the printing process of the microcapsule ink. Even when the microcapsule cannot be arranged at a desired position during printing, the solvent component in the microcapsule ink moves from the opening 10a to the void layer 9 to attract the microcapsule to the opening 10a ( I was able to suction it) and position it precisely at the pinpoint position. Next, the electrophoretic display device panel was manufactured by adjusting and adhering the above-mentioned second substrate 7 on which the third electrode 12 is formed with a thermosetting resin or an ultraviolet curable resin.

Example 4 As shown in FIG. 12, a first substrate 6 was manufactured in the same manner as in Example 1 above. The opening of the void portion 9 facing the outer periphery of the obtained first substrate was sealed, and the suction portion 16 connected to the pump so as to suck from a part thereof was formed. Thereafter, in the same manner as in Example 1, the microcapsule layer was formed, and the microcapsules 5 were aligned while being sucked. Hereinafter, in the same manner as in Example 1,
An electrophoretic display panel was created. In this device, the time for disposing the microcapsules 5 could be shortened. Moreover, the position accuracy was also improved.

The present invention has been described above with reference to the embodiments.
The electrophoretic display devices described in these examples are
The microcapsules can be arranged with high precision, and a display device having excellent resolution can be realized. Further, by injecting the coloring liquids having various different hues into the void layer 9, a display device having an excellent visual effect was realized. The present invention can be variously modified as long as it has the function of each constituent element adopted in these embodiments.

[0046]

As described above, according to the electrophoretic display device of the first aspect of the present invention, it is possible to realize a display device capable of changing the background color or the foreground color of the display screen with a simple structure. Further, in the electrophoretic display device manufacturing method of the second aspect of the present invention, the display color can be changed by simple matrix driving, so that a low-cost display medium can be provided.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a main part of an electrophoretic display device of the present invention.

FIG. 2 is a plan configuration diagram of an electrophoretic display device of the present invention.

FIG. 3 is a conceptual diagram illustrating movement of electrophoretic particles in the display device of the present invention.

FIG. 4 is a schematic top view of the electrophoretic display device of the invention.

FIG. 5 is a diagram illustrating a voltage application sequence to electrodes of the electrophoretic display device of the present invention.

FIG. 6 is a manufacturing process diagram of the electrophoretic display device according to the first embodiment of the present invention.

FIG. 7 is a cross-sectional view of essential parts of an electrophoretic display device that is a second embodiment of the present invention.

FIG. 8 is a perspective view of essential parts of an electrophoretic display device that is a second embodiment of the present invention.

FIG. 9 is a manufacturing process diagram of an electrophoretic display device that is a second embodiment of the present invention.

FIG. 10 is a cross-sectional view of essential parts of an electrophoretic display device that is a third embodiment of the present invention.

FIG. 11 is a manufacturing process diagram of an electrophoretic display device that is a third embodiment of the present invention.

FIG. 12 is a cross-sectional view of essential parts of an electrophoretic display device that is a fourth embodiment of the present invention.

FIG. 13 is a schematic view showing the shape of the opening of the present invention.

FIG. 14 is a cross-sectional view of a main part for explaining a prior art of an electrophoretic display device.

FIG. 15 is a cross-sectional view of a main part for explaining a conventional display device.

[Explanation of symbols]

1 ... Insulating liquid 2 ... Electrophoretic particles 3 ... Dispersion 4 ... shell 5: Microcapsules 6, 7 ... First and second substrates 8 ... Colored layer 9 ... Void layer 11a, 11b, 12 ... First, second and third electrodes 10 ... Surface layer 10a ... opening 13 ... Spacer 14-1, -2, -3, -4 ... Power supply circuit 15 ... Electrical wiring 16 ... Suction section

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Sadao Kajiura             1st Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa             Inside the Toshiba Research and Development Center (72) Inventor Hideyuki Nakao             1st Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa             Inside the Toshiba Research and Development Center

Claims (5)

[Claims] 1. A plurality of microcapsules consisting of a dispersion liquid in which a plurality of electrophoretic particles are dispersed in an insulating liquid and a shell containing the dispersion liquid, and the microcapsules arranged and held in a two-dimensional manner and A first and a second substrate provided with electrodes for applying an electric field to the microcapsules, and controlling the electric field applied to each of the microcapsules so that the electrophoretic particles encapsulated in the microcapsules are formed. In the electrophoretic display device for electrophoresis, the first substrate is arranged with a gap between the substrate body and the substrate body, and corresponds to a position where each of the microcapsules is arranged. And a surface layer having an opening penetrating the void portion. 2. A plurality of microcapsules consisting of a dispersion liquid in which a plurality of electrophoretic particles are dispersed in an insulating liquid and a shell containing the dispersion liquid, and the microcapsules arranged and held two-dimensionally. A first and a second substrate provided with electrodes for applying an electric field to the microcapsules, and controlling the electric field applied to each of the microcapsules so that the electrophoretic particles encapsulated in the microcapsules are formed. In the method of manufacturing an electrophoretic display device for electrophoresis, the first substrate is arranged with a gap between the substrate body and the substrate body, and each of the microcapsules is arranged. A surface layer having an opening penetrating the void corresponding to a position, and applying a coating liquid in which the microcapsules are dispersed on the surface of the first substrate. A method for manufacturing an electrophoretic display device, characterized in that the microcapsules are arranged corresponding to the openings by causing a liquid component in the coating liquid to flow out from the openings and the voids connected to the openings. . 3. The method of manufacturing an electrophoretic display device according to claim 2, wherein the surface layer forms the groove-shaped void portion between the surface layer and the substrate body. 4. The method of manufacturing an electrophoretic display device according to claim 2, wherein the surface layer is disposed on the surface of the substrate body via a partition or a spacer. 5. The method for manufacturing an electrophoretic display device according to claim 2, wherein the void portion is formed with a porous structure.