JPS59807B2 - image conversion element - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an element that converts an optical image of a specific wavelength, such as an X-ray, ultraviolet ray, visible light, or infrared image, into a liquid crystal scattering image in a sandwich cell using a field-effect nematic liquid crystal. It is something.

Essentially, nematic field-effect liquid crystals have the property that when an electric field is applied, the liquid crystal causes scattering, and by comparing this with the non-scattering part to which no electric field is applied, it is possible to recognize and distinguish patterns of characters, symbols, and optical images. However, it does not emit light itself, and the displayed image can be seen by external light. Therefore, identification of the displayed object is influenced by ambient light illumination and lighting, and this is a means of obtaining an optical image with sufficient brightness by using strong external light. The present invention utilizes this feature to realize an effective light conversion element, which converts weak optical images and invisible electromagnetic wave images into images with strong light intensity, and can be applied to various optical devices. That is. For example, an optical image intensifier (Imag)
eIntensifier), visible image converter for ultraviolet rays, This technology can be put to practical use in facsimile applications as a technology that combines these techniques.
Conventionally, liquid crystal cells equipped with a photoconductive material have been devised, but in these, both the light source for forming an image and the light beam for obtaining a scattered image must be limited depending on the characteristics of the photoconductive material. Also, there is an interface where the photoconductive material and the liquid crystal layer are in direct contact, and the interaction between the photoconductive material and the liquid crystal and the direct conduction of current affect the operational stability and lifespan of the liquid crystal. In the present invention, the wavelength of the image-forming light beam and the wavelength of the scattered image formation can be separated or selected by using an insulating layer, and at the same time scattering is caused by an alternating electric field, thereby preventing deterioration of the liquid crystal due to energization. and improve operational stability.
It is possible to extend its life. To explain the features of the present invention in more detail, the effects through the insulating layer are as follows:
The filter may reflect the scattered image-forming light beam, or absorb or reflect wavelengths of the image-forming light beam, or selectively transmit (or absorb) only certain wavelengths, such as a reflective insulator. Even if an image is formed at visible wavelengths through a layer, a light scattering image at visible wavelengths can be seen, and it can be used as an image intensifier that converts a weak visible light image into a strong visible light image.

This is because visible-to-visible image conversion can be performed by providing visible light reflection performance to the insulating layer according to the present invention, but the insulating layer has a structure that separates or separates the image-forming light beam and the scattered image light beam. By reflecting and providing selective properties, various changes are possible, and these are not limited to single layers, but can also be used as several types of composite multilayer films.

Therefore, the present invention is not particularly limited to these insulating layers, and by providing an insulating film, various optical modulations can be imparted to them, and moreover, direct contact between the photoconductive layer and the liquid crystal can be achieved. prevents electrode reactions and chemical interactions caused by
Moreover, it is based on the discovery that an alternating current electric field produces the same effect as scattering with a direct current electric field. The present invention will be explained below with reference to embodiments shown in the drawings.

9 shows a schematic cross section of a liquid crystal cell according to the present invention, in which 1 is a substrate, 2 is a conductive layer, 3 is a photoconductive layer, 4 is an insulating layer according to the present invention, and 5 is held by a suitable spacer. 6 is a conductive layer, 7 is a substrate, and 8 is a power source connected to the conductive layers 2 and 6 by lead wires.

Among the substrates 1 and 7 described above, at least the substrate 7 is transparent.

Generally, image forming light beams enter the cell 9 from 10 directions,
The photoconductive layer becomes conductive in accordance with the strength of the image light, and thereby a liquid crystal scattering image formed by the effect of an electric field is obtained as a reflected image from 11 directions, but it is also possible to obtain an image from 10 directions. In some cases, a light source for scattering images is used at the same time as the forming light beam.
Furthermore, it is also possible to simultaneously apply the image forming light beam and the light beam for scattering image in the 11 directions. The most typical application example of the device of the present invention will be described.

In the cell 9, the substrate 1 is made of transparent ordinary glass, the conductive layer 2 is an indium oxide transparent conductive electrode, the photoconductive layer 3 is cadmium sulfide, and on top of this is a metal oxide known as a cold mirror. (For example, high refractive index Ti
The insulating layer 4 has a thin film of O2, CeO2, etc.) that reflects visible light, which is alternately laminated with thin films with a low refractive index of 1/4 wavelength each, and the liquid crystal layer 5 has a room temperature liquid crystal (nematic liquid crystal ), for example, use p-methoxybenzylideneaminophenyl butyrate to make a cell with a transparent conductive electrode as the conductive layer 6 and glass as the substrate 7, make the spacer of the liquid crystal 5 15μ thick, and make the spacer of the liquid crystal 5 15 μm thick for the power supply 8. An alternating current electric field of ~100V is applied, and visible light is imaged on the CdS surface of the photoconductive layer 3 from the direction 10, and when viewed under sunlight stronger than the direction 11, a clear light scattering visible image is obtained. The photoconductivity of the above CdS was not affected by sunlight, which is external light.

[Brief explanation of drawings]

The drawings are explanatory diagrams illustrating the image conversion element of the present invention. 1...Substrate, 2...Conductive layer, 3...
...Photoconductive layer, 4...Insulating layer, 5...
-Liquid crystal layer, 6...conductive layer, 7...substrate, 8...power supply, 9...liquid crystal cell.

Claims (1)

[Claims] 1 A transparent electrode layer is provided on one side of one transparent substrate, and a visible light reflective insulating layer having a conductive electrode layer, a photoconductive layer, and a metal oxide layer is sequentially laminated on one side of the other substrate. 1. A liquid crystal image conversion element, comprising: a nematic liquid crystal layer sandwiched between the transparent electrode layer and the visible light reflective insulating layer.