JPH01280794A - Display device - Google Patents

Abstract

PURPOSE:To prevent separation of particles from a fluid even when the title display device is left untouched for a long period and, at the same time, to realize multicolored displays by forming small cells in a transparent insulating container and forming an electric field color developing medium by arranging numerous small cells on a conductive base plate. CONSTITUTION:When a control power supply 15 is impressed so that the upper- and lower-electrode 10a and 10b sides of a write electrode 10 can respectively become (+) and (-), the electric field is directed in the forward direction and corona ions pass. Then an electrostatic image is formed on small cells 22 on the electrode 10 and color development is performed. The color-developed image becomes a displaying image when it is viewed from a conductive transparent electrode 21 side. When the displaying image is erased, potential which is opposite to the potential applied at the writing is applied across a corona wire 11 and scanning is performed by setting corona ions to a passable state. Then corona ions of the polarity opposite to the polarity applied at the time of writing ride on the electric field color developing medium 20 and the displaying image is erased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a display device that can display high-resolution characters and graphics on a screen about the size of a blackboard.

[Conventional technology]

Conventionally, display devices capable of displaying images as large as a blackboard include those in which liquid crystal cells or CRTs are connected and arranged,
Alternatively, there is one that uses magnetophoresis.

By the way, in conventional display devices, the above-mentioned liquid crystal cell and C
Those using RT had the problem that the circuitry was complicated and expensive because the screen information was divided.

Furthermore, those using magnetophoresis have the problem that the magnetic head used during display scanning is complicated and expensive.

On the other hand, a display device that solves the above-mentioned problems is disclosed in Japanese Patent Laid-Open No. 62-34187. This device consists of a medium that develops color using an electric field and a writing electrode that controls corona ions.As the electrochromic medium, an electrophoretic medium is used in which charged colored particles migrate under the action of an electric field and develop color. This allows a large screen to be displayed at low cost.

[Problem to be solved by the invention]

However, because conventional electrophoretic media had an electrophoretic substance injected into a cell with a structure in which two substrates, at least one of which was transparent, were sandwiched through a spacer, if left for a long time, There are problems in which the particles settle and separate from the fluid, and particles and fluids of different colors cannot be kept separated from each other, making it impossible to display multiple colors of three or more colors.

In order to solve this problem, it is possible to divide the electrophoretic medium into many small cells using lattice-like spacers, but it is difficult to inject the electrophoretic material and it is difficult to remove the air bubbles. The problem was that it was difficult. In addition, when using a lattice-shaped spacer, it is difficult to inject particles and fluids of different colors while separating them from each other.
There was a problem that multicolor display of three or more colors was not possible.

This invention was made to solve the above problems, and provides a display device that does not cause separation of particles and fluid even if left for a long time, and that is capable of displaying three or more colors. The purpose is to

[i! l! Means to solve the problem]

In the display device according to the present invention, charged colored particles and colored fluid or non-colored fluid are sealed in a transparent insulating container to form small cells, and a large number of these small cells are arranged on a conductive substrate to form an electrochromic medium. It is composed of

Two or more types of small cells may be used that differ in the color combination of charged colored particles and colored fluid.

(Function) In the present invention, an electric field is applied to the small cell by a write electrode that controls the flow of corona ions to form an electrostatic image, thereby causing charged colored particles to move and displaying.

When small cells are used in combinations of various colors, a multicolor display can be obtained.

〔Example〕

FIG. 1 is a schematic diagram showing an embodiment of the present invention. In this figure, 10 is a write electrode that controls the flow of corona ions generated from the corona wire 11. Note that 12 is a shield case, and 13 is a write electrode control circuit. Further, 20 is an electrochromic medium, and a conductive transparent substrate 21. The small cell 22 mainly consists of a transparent insulating container 23 and charged colored particles 24 and colored fluid 25 accommodated therein. 22A shows a colored region that is colored due to the electric field. The corona wire 11 is a gold-plated tungsten wire with a diameter of 60 to 120 μm, and a positive or negative voltage of 4 to 10 kV is applied to generate corona ions.

The passage of corona ions through the write electrode 8i 10 is controlled based on the principle shown in FIGS. 2(a) and 2(b). The write electrode 10 is configured such that an upper electrode 10a and a lower electrode 10b are arranged at a predetermined interval, and a corona ion flow can pass through a through hole provided in the center. Reference numeral 14 denotes a high voltage power supply, and 15 denotes a control power supply, which are controlled by the write electrode control circuit 13 shown in FIG. 16 is a bias power supply.

Next, the operation will be explained.

As shown in Fig. 2(a), when the control power supply 15 is applied so that the upper electrode +Oa side is + and the lower electrode 10b side is -, the electric field becomes forward direction, corona ions pass through, and the
As in b), if the direction is the opposite, corona ions will not pass through. Using the electrostatic image writing electrode 10 based on the above principle, an electrostatic image is formed on the small cell 22 and colored. The colored image can be seen as a displayed image when viewed from the side of the conductive transparent electrode 21 made of glass or the like. When erasing a displayed image, apply a potential opposite to that during writing to the corona wire 11 to allow corona ions to pass through, and scan by applying corona ions of opposite polarity to that during writing or electrochromic medium 20. Get on top of it and the displayed image will be erased.

FIGS. 3(a) and 3(b) are external perspective views showing the structure of the small cell 22, showing an example of a transparent insulating container 23 having a rectangular and circular cross-sectional shape. Charged colored particles 24 and colored fluid 25 are placed inside a transparent insulating container 23 to form a transparent insulating container 2.
By sealing both ends of 3, a small cell 22 is produced. The transparent insulator container 23 only needs to be an insulator, and various materials can be used. However, a circular plastic tube or a plastic tube formed into a rectangular shape or the like has good mechanical resistance and transparency. is particularly suitable as it is an excellent insulating material.

FIG. 4 is an external perspective view showing an example of the electrochromic medium 20. FIG. A horizontally elongated transparent insulating container 2 filled with charged colored particles 24 and colored fluid 25 is placed on the surface of a conductive transparent substrate 21.
The electrochromic medium 20 is formed by arranging three small cells 22. This structure was effective in preventing separation in the vertical direction, such as sedimentation of the charged colored particles 24 due to the action of gravity.

FIG. 5 is an external perspective view showing another structure of the transparent insulator container 23, in which a transparent plastic duplex formed into a rectangular shape or the like is filled with charged colored particles 24 and colored fluid 25.
Bead-shaped small cells 22 are formed by regularly bonding them.

FIG. 6 is an external perspective view showing another example of the electrochromic medium 20. A transparent insulator container 2 is placed on the surface of the 4-electric transparent substrate 21.
The electrochromic medium 20 is formed by arranging bead-shaped small cells 22 filled with charged colored particles 24 and colored fluid 25 inside the coloring medium 3 . This structure not only prevents the charged colored particles 24 from settling, but also has the effect of preventing the charged colored particles 24 from shifting in the lateral direction due to repeated display operations.

FIG. 7 is an external perspective view showing still another example of the electrochromic medium 20. The electrochromic medium 20 is formed by arranging horizontally long small cells 22 filled with charged colored particles 24 and colored fluid 25 inside a transparent insulating container 23 on the surface of a conductive transparent substrate 21. Here, the electrolytic coloring medium 20 includes white charged colored particles 24 and yellow colored fluid 2.
5, a horizontally long small cell 22a containing white charged colored particles 24
and a horizontally long small cell 22b containing a magenta colored fluid 25.
, horizontally elongated small cells 22c containing white charged colored particles 24 and cyan colored fluid 25 are arranged periodically, and can display color.

FIGS. 8(a) and 8(b) are configuration diagrams showing the principle of operation using an electric field. The electrochromic medium 20 is composed of a transparent insulator container 23, an electrochromic layer 26, and a conductive transparent substrate 21. The conductive transparent substrate 21 consists of a transparent conductive film 21a and a transparent support 21b. The electrochromic layer 26 consists of charged colored particles 24 and a colored fluid 25 colored in a different color. colored fluid 25
As the material, a dye and an ionic surfactant dissolved in an insulating liquid such as high-purity petroleum (Esso Co., Ltd., trade name Isopar) or xylene were used. When the ionic surfactant is adsorbed onto particles, the particles become electrochemically stably charged and dispersed, and exhibit electrophoretic properties.

FIG. 8(a) shows the case where the transparent conductive film 21a is grounded and ten electrostatic images are written. Ten charged colored particles 2
4 is drawn toward the transparent conductor 1Ii21a according to the electric field formed by the electrostatic image, and the color of the f-electro-colored powder 24 is visible from the conductive transparent substrate 21 side. FIG. 8(b) shows a case where a - electrostatic image is written, and this time, on the contrary, the charged colored particles 24 are drawn toward the electrostatic image,
The color of the colored fluid 25 is visible from the conductive transparent substrate 21 side. Display is achieved by changing the polarity of the electrostatic image in this way.

FIGS. 9(a) and 9(b) are configuration diagrams showing another operating principle using an electric field, and the electrochromic N26 is composed of two types of charged colored particles 24a and 24b with different charged polarities and colors and an uncolored fluid. Consists of 27.

FIG. 9(a) shows the case where the transparent conductive film 21a is grounded and ten electrostatic images are written. Ten charged colored particles 2
4a is drawn toward the transparent conductive film 21a due to the electric field formed by the electrostatic image, and the conductive transparent substrate 2
The color of the charged colored particles 24a can be seen from the side 1. FIG. 9(b) shows a case where a negative electrostatic image is written, and this time, the charged colored particles 24b or the transparent conductive film 21a are drawn toward the charged colored particles 24b, and the charged colored particles are drawn from the side of the conductive transparent substrate 21. I can see the color of Powder 24b. Display can be performed by changing the polarity of the electrostatic image in this way.

Up to now, we have described the case where the display is viewed from the side of the conductive transparent substrate 21, but it is also possible to view the display from the side of the small cell 22 consisting of the electrochromic layer 26 and the transparent insulator container 23. . In that case, conductive transparent substrate 21 need not be transparent; instead, any opaque conductive substrate can be used.

FIG. 10 shows an external perspective view of an embodiment of the display device of the present invention. In this figure, reference numeral 30 denotes an electrostatic image writing section, in which a large number of the writing electrodes 10 shown in FIG. will also move accordingly. That is, an electrostatic image is written and displayed on the electrochromic layer 26 on the conductive transparent substrate 21 by scanning the writing electrode 10. It has an input terminal 31 for a power line (AC, 100 mm) and an input terminal 32 for a signal from a computer.

〔Effect of the invention〕

As explained above, the display device of the present invention uses an electrochromic medium, which is constructed by arranging small cells each containing charged colored particles and a colored fluid or an uncolored fluid in a transparent insulating container, arranged on a conductive substrate. Since it is used as a visualization medium, even if it is left for a long time, the charged colored particles and the colored fluid or uncolored fluid will not separate, so there will be no deterioration in display quality.

Furthermore, by using small cells with various color combinations, multicolor display of three or more colors is possible.

As described above, the present invention is very convenient when used as an electronic whiteboard in a conference, and has the advantage of increasing its utility value.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the configuration of an embodiment of the present invention, and FIG. 2 (
Figures a) and (b) are diagrams showing the principle of controlling corona ions by the writing electrode, and Figure 3 (a). (b) and FIG. 5 are external perspective views showing structural examples of a transparent insulator container, FIG. 4, FIG. 6, and FIG. 7 are external external perspective views showing structural examples of an electrochromic medium, respectively. (a)
, (b), Figure 9 (a). (b) is a diagram showing the operating principle of an electrochromic medium using an electric field;
FIG. 10 is an external perspective view of an embodiment of the display device of the present invention. In the figure, 10 is a write electrode, 10a is an upper electrode, 10b
1 is a lower electrode, 11 is a corona wire, 12 is a shield case, 13 is a write electrode control circuit, 14 is a high voltage power supply, 1
5 is a control power supply, 16 is a bias power supply, 20 is an electrochromic medium, 21 is a conductive transparent substrate, 21a is a transparent conductive film, 22
23 is a small cell, 23 is a transparent insulator container, 24 is charged colored particles, 25 is a colored fluid, 26 is an electrochromic layer, and 27 is an uncolored fluid. Snake) I+L, I

Claims (2)

[Claims] (1) A writing electrode that controls the flow of corona ions to form an electrostatic image, and an electric field that causes charged colored particles to migrate in a colored or uncolored fluid and develop color when an electric field is applied by the electrostatic image. In a display device made of a coloring medium, the charged colored particles and the colored fluid or uncolored fluid are sealed in a transparent insulating container to form a small cell, and the small cell is
A display device characterized in that a large number of the electrochromic media are arranged on a conductive substrate. (2) The display device according to claim (1), wherein two or more types of small cells having different combinations of charged colored particles and colored fluids are alternately arranged on a conductive substrate.