JPS5913000B2 - image conversion element - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The purpose of the present invention is to convert an X-ray image into a visible image,
The present invention relates to an X-ray visual conversion element that directly converts a ray image into a visible image with sufficient brightness and allows the user to safely view the image.

Essentially, nematic field-effect liquid crystals can be used to recognize and distinguish patterns in optical images such as letters and symbols by scattering the liquid crystal when an electric field is applied and comparing this with the non-scattering part to which no electric field is applied. However, it does not emit light itself, and the displayed image can be distinguished by external light.

Therefore, the identification of the displayed object is influenced by the illumination and daylighting of the surroundings, and this is a means of obtaining an optical image of sufficient brightness using strong external light. The present invention utilizes this feature to realize an effective X-ray visible conversion element.
Conventionally, fluorescent materials are the most well-known and widely used means of directly visualizing X-rays, but it is difficult to obtain sufficient brightness and the clarity is only second-order. It was difficult.

In response to this, a device using an electroluminescent material has recently been devised, but even in this case, in a sufficiently bright environment, sufficient contrast can be achieved due to the scattering and reflection of external light on the electroluminescent material and its support. It had the disadvantage of not being able to produce anything. Furthermore, there are devices such as microchannel plates known as image intensifiers, and devices that convert image pickup tubes into TV images, but these are difficult to put into practical use, have insufficient resolution, or are difficult to put into practical use. Since it essentially uses a light-emitting material, it has the drawback of reducing contrast due to external light. The X-ray visible conversion element according to the present invention eliminates these drawbacks and uses the principles of the image conversion element already developed by the present inventors to provide a light-receiving type image display that provides an extremely easy-to-see image when exposed to external light. It is easy to view directly, enlarge and project images, and take photographs.

This will be explained below with reference to embodiments shown in the drawings.

12 in FIG. 1 is a schematic cross-sectional view 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 a visible light reflective insulating layer, and 5 is a suitable spacer. 6 is a conductive layer, T is a substrate, and 8 is a power source connected to the conductive layers 2 and 6 by lead wires. Reference numeral 9 is a grid that cuts off scattered X-ray beams, and reference numeral 10 is an outer box lined with a lead plate to prevent leakage of X-rays to the outside.

Note that at least one of the substrates 1 and 7 is transparent, and it is effective to use so-called lead glass as the transparent substrate. Generally, X-rays are irradiated from 11 directions, and cell 1
An image is formed on the photoconductive layer 3 of the cell 12 as an X-ray image transmitted through the subject 14 placed between the cell 12 and the cell 12. A conductive pattern is formed according to the strength of the X-rays, and a scattering image can be obtained by applying an alternating current electric field to the conductive layers 2 and 6.
This scattered image can be illuminated from 13 directions or viewed as a visible image under external light. A more effective element according to the present invention, as shown in FIG. Although FIG. 2 shows a case where the visible light blocking layer 15 is formed outside the cell 12, the present invention is not limited to this.

In FIG. 1, the substrate 1 can be made of ordinary glass, the conductive layer 2 is made of indium oxide, tin oxide, or an extremely thin metal layer, and the photoconductive layer 3 is made of CdS, CdSe,
It is made of a material such as Se, Sb2S3, PbO, etc. that can obtain photoconductivity by X-rays.

The visible light reflective insulating layer 4 can be an optical thin film made of a metal oxide, in which low refractive index and high refractive index layers are alternately laminated at % wavelength. For example, if a substance called methoxybenzylidene butylaniline is used, the liquid crystal layer 5 exhibits a liquid crystal state at room temperature and can be easily used. For the electrode layer 6, a thin film of indium oxide, tin oxide, etc., which is known as a transparent conductive film, is effective. For the substrate 7, a lead-containing glass plate is used whose lead content and thickness are taken into consideration depending on the X-ray intensity. If an AC power source of about 15 to 100 V is used as the power source 8, a good scattering state can be obtained when the liquid crystal layer is about 10 to 50 microns. The thickness of each thin film is determined by the intensity of X-rays and manufacturing reasons, but is approximately in the range of 0.1 μm to 10 μm, which can be considered as the optical thickness. When a panel with such a structure is irradiated with X-rays in a prescribed manner, after the photoconductive layer is made conductive by the X-rays, the leaked X-rays reach the lead glass of the substrate on the observer side of the panel. Therefore, the radiation is absorbed and the observer can be prevented from being harmed by X-rays.

On the other hand, the reflective insulating layer completely blocks the photoconductive material from becoming conductive due to external light, and at the same time reflects the scattered light caused by forward scattering of the liquid crystal toward the observer, thereby preventing the influence of external light. At the same time, it increases scattering contrast. Furthermore, since ultraviolet light is blocked by the lead-containing glass and the transparent electrode layer, it does not affect the photoconductive surface. The X-ray visible image converter thus obtained can be viewed as a sharper image as long as there is sufficient external light, and it also facilitates photographing and enlarged projection. As shown in Figure 2, when an opaque plastic material is coated on the X-ray irradiation side as a member to block visible light, or when the substrate itself is made of opaque glass, both the subject part and the observer's side should be placed in a bright place. This makes it possible to operate the device, and it can become an extremely effective X-ray observation equipment for non-destructive inspection of products.

It is also possible to use an X-ray grid as the opaque member 15, and use an opaque adhesive around the periphery of the cell 12 in close contact with the cell 12. As described above, the X-ray visible conversion element according to the present invention has an insulating layer based on the image conversion element developed earlier by the present inventors, and thus becomes an extremely practical element and at the same time can safely convert X-ray images. If only direct viewing and an X-ray source are provided, it can be used as a lightweight, portable panel, and can be used to inspect various product processes without interfering with them, or as equipment for experimental research. This makes it easy to incorporate it into the system.

[Brief explanation of drawings]

FIGS. 1 and 2 are explanatory diagrams of image conversion elements according to embodiments of the present invention. 1...Scarred plate, 2...Conductive layer, 3...
...Photoconductive layer, 4...Visible light reflective insulating layer, 5
...Liquid crystal layer, 6... Conductive layer, 7...
... Board, 8... Power supply, 9... Grid, 10... Outer box lined with shingle board, 12...
...Liquid crystal cell, 14...Subject, 15...
...Visible light blocking layer.

Claims (1)

[Claims] 1 It has a nematic liquid crystal layer sandwiched between two substrates, one of which is a transparent substrate made of lead-containing glass, with a transparent electrode layer provided on its inner wall surface, and the other substrate is a transparent substrate made of lead-containing glass. The whole or the wall surface of the substrate is made of a material that is transparent to X-rays and opaque to visible light, and a conductive electrode layer, a photoconductive layer, and a visible light reflective insulating layer are provided on the inner wall surface of the substrate. A liquid crystal image conversion element characterized by: