JPH04367826A - Optical modulating element - Google Patents

Abstract

PURPOSE:To obtain the optical modulating element of high quality with an optical address by utilizing an optical switching element. CONSTITUTION:The photoconductor part 12 of an (N)th line electrode 11 (scanning electrode) is irradiated with linear line by, for example, an EL element from behind and then the resistance of the photoconductor part 12 decreases, thereby applying a voltage pulse from a voltage supply source 14 through a bus bar. At this time, a display signal voltage is applied from the line electrode 15 (signal electrode) of the other substrate to apply an electric field corresponding to a target pattern to the optical modulating element (e.g. liquid crystal element) sandwiched between both the substrates. Similarly, an (N+1)th line is selected and a pattern is written. This operation is repeated in order to make a large-capacity matrix display.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical modulation element, a shutter, and a display device, and more particularly to a large-capacity optical modulation element having a switching element.

0002

2. Description of the Related Art Conventionally, optical modulation elements have had the disadvantage that contrast, brightness, etc. decrease when the capacity increases.

[0003] In particular, the STN method (super twisted nematic method) is currently widely used as a display element.
However, as the capacity increases, there are problems with contrast, brightness, response time, etc., and display quality deteriorates.

In order to overcome these drawbacks, a system called an active matrix system in which each pixel is provided with a switching element is currently being considered. In such a method, each pixel is provided with a transistor element (this is called a TFT method), or a two-terminal element (MIM method: metal insulated metal, or a method with a diode element, etc.) is provided. Things can be given.

[0005] In these systems, although there is little deterioration in display quality due to increase in capacity, the manufacturing process is complicated.

[0006]

[Problems to be Solved by the Invention] Although the active matrix method is useful in dealing with the quality deterioration that accompanies the increase in capacity, it has a complicated structure or a complicated process, resulting in poor yield and tact time. As a result, there was a problem that the cost was high.

An object of the present invention is to eliminate the above-mentioned drawbacks and provide an active element suitable for a large-capacity optical modulation element.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention uses active elements that are switched by light.

[0009]

[Operation] Application of non-selective waveforms is prevented by switching by light instead of the conventional active matrix switching by voltage.

For example, by connecting a photodiode to each pixel and sequentially irradiating the lines with light, voltage can be applied to each line, which has the effect of shutting out unselected waveforms (hereinafter referred to as crosstalk) that degrade display quality. Therefore, deterioration in display quality due to increase in capacity can be prevented. Furthermore, since it has a simpler configuration than the conventional active matrix method, it has the effect of easily reducing costs.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An optical modulation element according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 shows a configuration diagram of the optical modulation element of the present invention. In the same figure, indium
A photoconductor section 23 made of cadmium sulfide (hereinafter abbreviated as CdS) was installed in each pixel 22 made of a tin oxide transparent electrode (hereinafter referred to as an ITO electrode).

These pixels are connected in a line by lines 24 (hereinafter referred to as bus bars) made of aluminum. In addition, another substrate 25 on which ITO electrodes 22 were etched in a line shape was fabricated. RN707 (manufactured by Nissan Chemical Co., Ltd.) was formed as an organic alignment film on both substrates using a normal printing method. Thereafter, both substrates were subjected to an alignment treatment using a normal rubbing method so as to form a liquid crystal panel with a 90° twist configuration.

Next, sealing resin 2 is applied to bond both substrates.
6 (Structbond manufactured by Mitsui Toatsu Co., Ltd.) was screen printed around the substrate 25 using a conventional method. After this, board 2
After scattering 5 μm spacers (Micro Pearl manufactured by Sekisui Fine Chemical Co., Ltd.) on the substrate 5 at a density of about 150 spacers/square millimeter to adjust the distance between the substrates, the substrate 11 is bonded to the substrate 11 at a pressure of about 0.5 kg/square centimeter at 135°C. After curing under pressure for 30 minutes, a blank panel was produced by main curing at normal pressure of 150° C. for 2 hours. At this time, the upper and lower line electrodes were bonded together so that they crossed each other.

A liquid crystal panel was obtained by injecting liquid crystal into the blank panel thus prepared using a nematic liquid crystal ZLI4792 (manufactured by Merck & Co., Ltd.) by a conventional vacuum injection method. EL (electroluminescence) was used as the light supply means.

FIG. 3 shows a cross-sectional configuration diagram of a liquid crystal panel as an example of the optical modulation element manufactured by the present invention. In the figure, 31 indicates upper and lower glass substrates, 32 an ITO electrode, 33 an alignment film, 34 a liquid crystal layer, and 35 a sealing resin.

EL3 is attached to the photoconductor portion 36 of each pixel.
Light can be emitted in a line from 7, and various drive waveforms can be applied to the line electrodes of the upper and lower substrates using program voltage generators as voltage supply sources.

FIG. 1 shows an actual operational configuration diagram of an optical modulation element which is an example of the present invention. In the figure, the photoconductor portion 12 of the Nth line electrode 11 (scanning electrode) is irradiated with light in a line form from the EL 13 from the rear.
The resistance of was reduced and a voltage pulse was applied from the voltage supply 14 through the bus bar.

At this time, the line electrode 1 of the other substrate
A signal voltage for display was applied to 5 (signal electrode), and an electric field corresponding to a desired pattern was applied to the liquid crystal layer sandwiched between both substrates. Next, the N+1st line 16 was selected, and a signal voltage was applied while synchronizing the EL irradiation in the same manner. At this time, the EL irradiation on the Nth line was turned off. By selecting lines sequentially in this way, various display patterns could be shown.

[0020] Although the above explanation mainly uses EL light, it is not limited to this, and it is also possible to use an optical shutter element (for example, a ferroelectric liquid crystal element).
It goes without saying that a photodiode can also be used as the optical switching element.

[0021]

As described above, the present invention is an element that performs optical modulation by addressing with light, and has the effect that the display quality does not deteriorate as the capacity increases. Furthermore, since the manufacturing process is much simpler than that of conventional active matrix (TFT, etc.), it has the effect of reducing costs.

[Brief explanation of drawings]

FIG. 1: An actual operational configuration diagram of an optical modulation element that is an example of the present invention.

FIG. 2 is a configuration diagram of an optical modulation element according to an embodiment of the present invention.

[Figure 3
] Cross-sectional configuration diagram of a liquid crystal panel as an example of the optical modulation element of the present invention

[Explanation of symbols]

11 Nth line (scanning electrode) 12 Photoconductor part 13 EL 14 Voltage supply source 15 Line electrode (signal electrode)

Claims (9)

[Claims] 1. An optical modulation element having a matrix configuration, comprising a light-switching element between a scanning line and a portion where optical modulation is performed. 2. An optical modulation element characterized in that a liquid crystal element is used as the optical modulation element. 3. The optical modulation element according to claim 1, wherein the switching element has a resistance that changes depending on light. 4. The optical modulation element according to claim 1, wherein the switching element is a photodiode. 5. An optical modulation element, characterized in that a switching element is irradiated with light line-sequentially, and an electric field is synchronously applied to the optical modulation element. 6. The optical modulation element according to claim 5, wherein the optical modulation element is a liquid crystal element. 7. The optical modulation element according to claim 5, wherein an electroluminescence element is used to line-sequentially irradiate the switching element with light. 8. The optical modulation element according to claim 5, further comprising an optical shutter element for irradiating the switching element with light line-sequentially. 9. The optical modulation element according to claim 8, wherein the shutter element is a ferroelectric liquid crystal element.