JPS6040618B2 - image display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an image display device using an electro-optic medium such as a liquid crystal, in which the display section operates an element composed of many picture elements in a multi-digit time-division driving system, The purpose of this is to enable display of information, TV images, etc.

In recent years, there has been active research into display devices that can replace cathode ray tubes (CRTs), and in particular, flat-type display devices are being actively developed.

Among them, the liquid crystal display is a light-receiving type display, consumes little power, has a low driving voltage, and has a simple panel configuration, so the development of matrix display devices is expected. However, matrix displays using liquid crystals have problems such as crosstalk, and unless a storage type liquid crystal (with memory function) is used, which can only be used to display still images, the number of scanning electrodes that can be time-divisionally driven is limited. Sisters,
In reality, even if temperature compensation is performed, time-division driving of only about a few dozen scanning electrodes is possible.

Therefore, it has been almost impossible to display high-resolution TV images except by integrating switching elements for each picture element.
The present invention overcomes the above-mentioned drawbacks of the conventional art and provides an image display device that has a simple configuration and is capable of time-division driving of several tens or more digits.

The principle of the present invention is that when a photoconductive layer and an electro-optic medium such as a liquid crystal are electrically connected in series and a voltage is applied to both ends, when no incident light is irradiated onto the photoconductive layer, the voltage is almost light. When the incident light is applied to the conductive layer and the photoconductive layer is irradiated, a voltage is applied to the electro-optic medium such as liquid crystal, and the optical properties of the electro-optic medium change. The photoconductive surface is scanned by the photoconductive surface, and an image signal is supplied by applying a voltage.The voltage is applied only to the electro-optic medium of Sohata that receives the incident light momentarily, and the display is sequentially performed. It is something. The details of the present invention will be described below using Examples.

Example 1 FIG. 1 schematically shows the configuration of an electro-optical element used in implementing the present invention. This electro-optical device consists of a transparent glass substrate 2 on which a transparent electrode layer 1 divided into 250 lines is attached, and a light reflection layer 3 divided into 250×250 picture elements.
It has a structure in which a liquid crystal layer 8 exists between a photoconductive layer 4 and a transparent glass substrate 6 on which a transparent electrode 5 is attached with a surfacer 7 interposed therebetween. The light reflecting layer 3, which is divided into picture elements, is formed of a finely processed AI thin film, and each row thereof is arranged so as to overlap with a linear transparent electrode 1 made of indium oxide to form a cell. . The liquid crystal used is a negative nematic liquid crystal, which causes dynamic scattering (DS) when a voltage is applied. Further, as the photoconductive layer 4, a deposited film of CdSe is used. FIG. 2 shows a schematic configuration of an image display device used in Example 1 of the present invention.

Light emitted from the He-Ne laser light source 9 (^=688 ribs) is reflected by the surface of the rotating mirror 10 and irradiated onto the cylindrical mirror 11. At this time, the reflected light is repeatedly swept from top to bottom of the cylindrical mirror 11 (frequency: 30 days Z) and irradiated. Then, the light reflected on the surface of the cylindrical mirror 11 spreads in a plane,
The light on this plane is applied to the photoconductive surface of the electro-optical element 12 in a horizontal straight line and is swept from top to bottom. On the other hand, the electro-optical element 12 has the configuration shown in FIG. 1, and is set so that the linear transparent electrodes are oriented vertically. , a linear light is irradiated in a direction perpendicular to the length direction of the good-shaped transparent electrode layer 1. At this time, the linear portion of the photoconductive layer 4 that is irradiated with the light has a low resistance, and this portion has a low resistance. An electrical signal is applied only to the liquid crystal layer in contact with it, and no electrical signal is applied to most other liquid crystal layers.Therefore, the optical signal acts as a gate signal for each line, and one line of the image is , will be displayed at the same time.Next, by a slight rotation of the rotating mirror 10, the laser emitted from the laser light source 9 will scan the cylindrical mirror 11 in the vertical direction. The light that spreads out is swept in the vertical direction, and therefore the displayed lines shift in the vertical direction, resulting in a line-sequential scanning display.Also,
In the driver 13, a sampled signal of the TV image signal corresponding to 250 TV lines is converted into an applied voltage,
250 of the transparent electrode layer 1 in synchronization with the optical scanning signal.
It is supplied between each line of the book and the common transparent electrode 5. As a result, a pulse voltage of approximately 133 As was applied to the liquid crystal layer corresponding to the Tanie element at a cycle of 30 Hz.
The liquid crystal responds by following the effective value. The TV images displayed as described above still have some problems, which are thought to be caused by the rather long response time of the liquid crystal itself, but it is possible to display a high-quality image without any crosstalk. did it. In the above embodiments, a direct view type image display device is shown, but it is also possible to enlarge and project images by using a projection optical system. This embodiment is shown in FIG. 26
2 is a scanning optical system shown in FIG. 2, and 27 is an electro-optical element shown in FIG.

Image information is formed on the liquid crystal layer of the electro-optical element 27. Light emitted from the projection light source 28 and condensed onto the bar mirror 301 by the condenser lens 29 is reflected while changing direction, and is incident on the electro-optical element 27 by the projection lens 31 as a parallel beam. Here, the light incident on the picture element that is not scattered by light is directly reflected by the reflective layer, and is focused again on the bar mirror 30 by the lens 31, where the light is blocked. However, the light incident on the picture element that causes light scattering is reflected as scattered light, and this light is reflected by the projection lens 3.
1, the light passes outside the bar mirror 30 and is imaged on the screen 32. That is, image information formed on the liquid crystal layer of the electro-optical element is enlarged and projected onto the screen. In the above embodiments, a liquid crystal exhibiting a dynamic scattering phenomenon was used as the electro-optic medium, but even if a field-effect liquid crystal is used, in principle it is possible to display high-quality images without crosstalk in exactly the same way. The thing is clear.

Further, electro-optic media other than liquid crystal, ie, P is T, thermoplastic, KDP, etc., can also be applied as the electro-optic media of the present invention. As described using the embodiments, the image display device according to the present invention is a device that can display high-quality images by multi-digit time-division driving, and is considered to be of great value.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of an electro-optical element according to Example 1 for explaining the present invention, FIG. 2 is a schematic configuration diagram of an image display device according to Example 1, and FIG. 3 is a projection type image according to Example 2. FIG. 1 is a schematic configuration diagram of a display device. 8... Electro-optic medium (liquid crystal), 4... Photoconductive layer, 12, 27... Electro-optic element. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. An electro-optic medium whose optical properties change in response to an electrical signal supplied from the outside and a photoconductive layer whose resistance value changes in response to light irradiation are arranged in series between opposing electrodes. is,
Among the opposing electrodes, at least one electrode is arranged in one direction and is composed of a group of elongated electrically independent electrodes, and at least the electrode on the side that contacts the electro-optic medium is a transparent electrical an optical element means, a means for independently supplying an electrical signal corresponding to an image signal to each of the electrode groups, and a resistor of the photoconductive layer applied to the photoconductive layer in a direction substantially perpendicular to the longitudinal direction of the electrode group. An image display device comprising means for supplying linear light that causes a change, and for sweeping the linear light in the longitudinal direction of the electrode group in accordance with the image signal. 2. The image display device according to claim 1, wherein the electro-optic medium is a liquid crystal.