JPH0652358B2 - Display device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a display device which is thin, has no flicker, and has good display quality.

[Conventional technology]

Conventionally, as this type of display device, there is one that uses the principle of electrophoresis, and FIG. 7 shows a cross-sectional view of an example thereof. 7th
In the figure, a colored or opaque insulating liquid 5 containing charged colored particles 6 therein is shown as a sealing member 1 and a separating member 2.
The cells are filled with a cell-shaped space formed by, the individual transparent electrode 3 is arranged for each cell 7 on the display surface, and the grounded common electrode 4 is arranged on the other surface. To operate this, the individual transparent electrode 3 is selectively applied with a potential of about several tens of V, which is opposite to the charge polarity of the charged colored particles 6, in accordance with the display signal. Then, the individual transparent electrodes 3 to which an electric potential is applied
The charged colored particles 6 in the cell 7 corresponding to the
The charged colored particles 6 in the cell 7 corresponding to the individual transparent electrode 3 to which no electric potential was applied, remain on the common electrode 4 side while moving to the side by the principle of electrophoresis. Since the insulating liquid 5 in the cell 7 is opaque or colored, when viewed from the surface of the individual transparent electrode 3, the cell 7 in which the charged colored particles 6 are gathered on the individual transparent electrode 3 side is close to the color of the charged colored particle 6. Visible cell 7 in which charged colored particles 6 are gathered on the common electrode 4 side
Then, it looks like the color of the insulating liquid 5 itself. Therefore, display can be performed by selectively applying a potential to any individual transparent electrode 3.

[Problems to be solved by the invention]

Since the conventional display device utilizing electrophoresis has such a configuration and operation, it is essential that the insulating liquid 5 in the cell 7 is opaque or colored. For this reason, it is generally difficult to form the insulating liquid 5 with a single component, and it is common that the insulating liquid 5 is formed by mixing some colored particles or ions in the insulating liquid 5. The presence of particles or ions for liquid coloring tends to act as a destabilizing factor for the desired electrophoretic phenomenon when attempting to electrophorese charged particles for display, and thus stability as a display device. However, it had the drawback of significantly shortening the life.

[References on conventional technology: SID 84 DIGEST P142 "A Def
ect-Tolerant Active-Matrix Electro-phoretic Displa
y "Reference] An object of the present invention is to provide an electrophoretic display device that eliminates the unstable element of the electrophoretic phenomenon in the conventional electrophoretic display device.

[Means for solving problems]

The display device according to the present invention displays the visible area of the cell containing the charged colored particles when the charged colored particles are at the position on the display surface side in order to display by utilizing the electrophoretic phenomenon. This is different from the case where it is located away from the surface.

[Action]

According to the present invention, when the charged colored particles are gathered on the display surface side by the application of an electric field and when they are gathered apart from the display surface, the area covered by the charged colored particles is different, so that the color is changed, whereby a display is made. It

〔Example〕

FIG. 1 is a sectional view for explaining the first embodiment of the present invention.

In FIG. 1, a cell 7 composed of a separating member 2 and a sealing member 1 is filled with a mixture of an insulating liquid 5 and an organic substance containing an ionic surfactant and a pigment.
As a result, the ionic surfactant is adsorbed to the organic substance containing the pigment, is electrochemically stabilized, and is dispersed to exhibit the electrophoretic property. The cross-sectional shape of the cell 7 is different from that of the conventional example shown in FIG.

In order to operate this, the desired individual transparent electrode 3 is applied with a potential opposite to the charge polarity of the charged colored particles 6 of about several tens of V in accordance with the display signal. Then, the charged colored particles 6 in the cell 7 at the position corresponding to the individual transparent electrode 3 to which the potential is applied move to the individual transparent electrode 3 side by the electrophoretic phenomenon and correspond to the individual transparent electrode 3 to which the potential is not applied. The charged colored particles 6 in the cell 7 at the position to be left remain on the common electrode 4 side.
Since each cell 7 has a conical shape whose cross-sectional area decreases from the individual transparent electrode 3 side toward the common electrode 4 side, when the charged colored particles 6 gather on the common electrode 4 side, they gather on the individual transparent electrode 3 side. The area covered by the charged colored particles 6 viewed from the display surface side is smaller than that in the case. Therefore, in the cells 7 in which the charged colored particles 6 are gathered on the individual transparent electrode 3 side, the color of the charged colored particles 6 seems to be dominant, and the cells 7 in which the charged colored particles 6 are gathered on the common electrode 4 side are other than the charged colored particles 6. Separation member 2
Alternatively, the color of the common electrode 4 becomes dominant, and this change is used for display.

Since the insulating liquid 5 in the cell 7 is transparent, it can be configured without containing a dye or the like, and in the insulating liquid 5 compared to the insulating liquid 5 containing a dye or the like as in the prior art. The stability of the electrophoretic phenomenon and the life of the charged colored particles 6 are significantly improved.

Although the individual transparent electrode 3 is used as the display surface in the above embodiment, the common electrode 4 may be used as the individual transparent electrode 3 and the common electrode 4 side may be used as the display surface. Further, the cross-sectional area of the cell 7 is shown to be larger toward the individual transparent electrode 3 side, but of course the opposite may be true.

In this embodiment, the cell 7 may have a depth of about several tens of μm.

Further, as the insulating liquid 5, for example, high-purity petroleum (for example, trade name of Esso Co .: Isopar) may be used. It is desirable that the sealing member 1 and the separating member 2 be made of an insulator.

2 to 4 are views showing the sectional shape of the cell 7 of another embodiment of the present invention.

If the bottom areas of one side and the other side of the display surface are different, the cell 7 can have various shapes as shown in these drawings.

Further, the shape of the cell 7 viewed from the display surface can be various shapes such as a circle and a rectangle, and it does not matter even if it is directly in the shape of a character.

FIG. 5 is a view showing still another embodiment of the present invention,
1A is a transparent sealing member, and 2A is a colored separating member. In this embodiment, the bottom areas of the cells 7 on the individual transparent electrode 3 side and the common electrode 4 side are the same, but there is a constriction in the middle of the cell 7, and the cell 7 itself has a colored separating member 2A. Therefore, when the charged colored particles 6 are on the individual transparent electrode 3 side, the color of the charged colored particles 6 appears dominant, but when the charged colored particles 6 are on the common electrode 4 side, the individual transparent When viewed from the electrode 3 side, the color of the wall surface of the cell 7 appears to be dominant, and display can be performed by the difference between the two colors. According to this embodiment, the charged colored particles 6
The housing portion of the is wider than the embodiment of FIGS. 1 to 4,
The overall thickness can be reduced.

FIG. 6 is a view showing still another embodiment of the present invention,
Reference numeral 8 is a corona ion generator, 9 is an ion flow control plate, 10 is a surface charge, 11 is an ion flow control pulse, and others are the same as in FIG.

In order to operate this, a high voltage of about several Kv is applied to the corona ion generator 8 to generate corona ions, and an ion flow controlling pulse is applied to the ion flow control plate 9 to add the ion flow emitted from the corona ion generator 8. ON-OFF control is performed by 11, an electrostatic image is formed by the surface charge 10 on the transparent sealing member 1A, and the charged colored particles 6 are electrophoresed by the electric field generated by this electrostatic image. Is displayed in the same manner as.

After all, the individual transparent electrodes 3 as in the embodiment of FIGS.
Instead of giving an electrophoretic electric field by means of the above, the electric field for electrophoretic is given by the surface charge 10 due to the irradiation of the ion stream, and the structure of the display medium, the driver circuit, etc. are further provided as compared with the case where the individual transparent electrode 3 is installed. Can be simplified.

In this embodiment, in order to erase the image once formed, for example, uniform corona charging having a polarity opposite to that at the time of writing may be performed. Also in the embodiment shown in FIG. 6, the shape of the cell 7 and the relationship between the upper and lower sides of the cell 7 can be in various forms as in the above-mentioned embodiments.

Of course, a means for forming an electrostatic image by using a pin electrode for electrostatic recording may be used instead of using the ion current.

In the embodiment using the individual transparent electrodes 3 described above, the individual transparent electrodes 3 and the common electrodes 4 may be formed in a matrix, and a desired cell 7 may be selected for display.

Further, the insulating liquid 5 in each of the above embodiments may be opaque or colored.

〔The invention's effect〕

As described above, in order to perform display using the electrophoretic phenomenon, as described above, the visible area of the cell in which the charged colored particles are housed is as follows: Since it is different from the case where it is located away from the display surface, it suffices to disperse the particles to be electrophoresed in a transparent insulating liquid. Since it is not necessary to add colored particles,
There is an advantage that the electrophoretic phenomenon is stabilized and, as a result, the stability and life of the display device are very long.

In addition, as an application field of the present invention, a thin display device can be formed, and since it has no flicker, it can be applied as a display device replacing a CRT.

Also, since it is easy to configure a large-screen display device, it can be applied as a large-screen display or as a bulletin board-like display device for a large number of people to see at the same time.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention, FIG. 2 and FIG.
4 and 5 are sectional views showing the shape of an electrophoretic cell according to another embodiment of the present invention, FIG. 5 is a sectional view showing yet another embodiment of the present invention, and FIG. FIG. 7 is a sectional view showing another embodiment, and FIG. 7 is a sectional view showing an example of a conventional display device using the electrophoretic phenomenon. In the figure, 1 is a sealing member, 2 is a separating member, 3 is an individual transparent electrode, 4 is a common electrode, 5 is an insulating liquid, 6 is a charged colored particle, 7 is a cell, 8 is a corona ion generator, and 9 is An ion flow control plate, 10 is a surface charge, and 11 is an ion flow control pulse.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshio Nishida 162 Shirahane, Shirahoji, Tokai-mura, Naka-gun, Ibaraki Prefecture, Nippon Telegraph and Telephone Corporation, Ibaraki Telecommunications Research Institute (56) Reference JP-A-59-171930 (JP, A)

Claims (3)

[Claims] 1. The charged colored particles are displayed on a display surface when the electric field is not applied and when the electric field is applied by utilizing the electrophoretic phenomenon of the charged colored particles dispersed in an insulating liquid enclosed in a closed cell. From the position away from the display surface side, or vice versa, in the device for performing display, the visible area of the cell containing the charged colored particles, the charged colored particles to the display surface side position. A display device characterized in that it is different from the case where it is present and the case where it is located away from the display surface. 2. A shape in which a required portion on the inner surface side of a sealed cell is made opaque, and a cross-sectional area parallel to the display surface of this cell is the minimum at an intermediate portion between the display surface and the opposite side of this display surface. The display device according to claim (1), characterized in that. 3. The display device according to claim 1, wherein the electric field is applied by irradiating a corona ion flow.