JPS6213782B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a method for manufacturing a fluorescent surface that converts radiation images such as X-rays and γ-rays and electron beam images into visible images.

Fluorescent surfaces that convert high-energy radiation images such as X-rays and γ-rays and electron beam images into light images are used, for example, on the input surface and output surface of an X-ray fluorescence multiplier tube, the fluorescent plate, and the electron multiplier of a night vision tube. Used for the output surface of double-type image pickup tubes, etc. The main characteristics of such fluorescent surfaces are resolution and conversion efficiency.

Figure 1 shows a cross-sectional view of the input surface of an X-ray fluorescence multiplier tube, which is an example of the use of a conventional fluorescent surface.
In the figure, the input surface of the linear fluorophore multiplier tube is made by laminating a phosphor layer 2 made of cesium iodide on an aluminum substrate 1, and further forming a photocathode 3 on the upper surface of the phosphor layer 2. are doing. When this input surface is irradiated with X-rays 4, the X-rays 4 pass through the substrate 1 and cause the phosphor to emit light. Light emitted at one point P of the phosphor layer 2 is emitted in all directions. Therefore, when the light emitted at one point P reaches the upper surface of the phosphor layer 2, "blur" occurs. This blur increases as the distance from the upper surface of the phosphor layer to point P increases. That is, the phosphor layer 2
As the thickness increases, the blur increases and the resolution decreases. On the other hand, the conversion efficiency of the phosphor surface improves as the thickness of the phosphor layer 2 increases, and it is difficult to achieve both resolution and conversion efficiency.

An input screen having a structure as shown in FIG. 2 has been proposed as a high-resolution image intensifier screen that improves the above-mentioned conventional drawbacks. That is, there are a large number of small chambers 13 that are formed on one surface of the aluminum substrate 11 and partitioned by light shielding walls 12 that protrude from the aluminum substrate 11 in the vertical direction. This light shielding wall 12 is thin and opaque to the light emitted by the phosphor 14 filled in the small chamber 13. Small room 13
A phosphor made of, for example, cesium iodide is filled inside the phosphor layer 14 by vapor deposition or the like to form a phosphor layer 14. A photocathode 15 is formed on the upper surface of the phosphor layer 14. When the input surface having such a structure is irradiated with X-rays 16, the X-rays 16 pass through the aluminum substrate 11 and cause the phosphor layer 14 to emit light. Light emitted at one point Q on the phosphor layer is emitted in all directions. However, the light emitted laterally is reflected by the light shielding wall 12 and extracted only onto the upper surface of the small chamber 13. Since the lateral diffusion of light is thus restricted, an input surface with good resolution can be provided. Further, even if the phosphor layer 14 is thickened to improve conversion efficiency, the resolution does not deteriorate.

By the way, regarding the manufacturing method of the input surface of the above-mentioned structure, especially the fluorescent surface, the present applicant previously published Japanese Patent Application No. 52-102571.
It is proposed as. That is, the above manufacturing method includes a step of forming a mosaic pattern on the surface of a substrate, a step of filling a light-shielding material into the grooves that partition the mosaic pattern, and a step of removing the mosaic portion leaving the filling material and filling the surface of the substrate. The method consists of a step of forming a light-shielding wall with a material made of the same material, and a step of forming a phosphor layer on the substrate.

Therefore, the present invention is a further improvement of the invention of the above-mentioned Japanese Patent Application No. 52-102571, and includes a fluorescent input surface, particularly a fluorescent surface, having the structure shown in FIG. 2, which can be manufactured easily and with good reproducibility. A method of manufacturing a light surface is provided.

That is, in the method for manufacturing a fluorescent surface according to the present invention, when forming a light shielding wall, an auxiliary layer of a mosaic structure is formed on the surface of a substrate by an electrochemical method, particularly a plating method, and then a groove section is formed to partition the mosaic structure. After filling the substrate with a light shielding material and removing the mosaic portion while leaving the filling material so that the material filled on the substrate surface remains on the substrate as a light shielding wall,
This forms a phosphor layer. For forming the phosphor layer, a well-known method of vapor depositing an alkali halide phosphor is applicable to the present invention.
However, the invention is not limited to alkali halide phosphors.

Embodiments of the present invention will be described below in Figures 3 to 6.
This will be explained with reference to the figures.

Example 1 After cleaning the surface of an aluminum substrate 21 with a thickness of 0.5 mm by degreasing and etching, chromium is plated on the aluminum substrate 21 as an auxiliary layer 22 on the surface on which the phosphor layer is to be formed under the following conditions. . The temperature is maintained at 30 to 70°C in a plating bath consisting of 200 to 500 g of chromium trioxide and 0.5 to 2 g of sulfuric acid, and chromium is deposited to a thickness of about 50 μm at a current density of 10 to 50 A/dm ² . The formed chromium layer forms a mosaic with fine cracks (not shown) to form an auxiliary layer 22. After thoroughly cleaning the substrate,
When heat-treated at .degree. C., the mosaic of the auxiliary layer 22 is further refined by cracks, and at the same time, the mosaic chromium surface 23 is oxidized and inactivated. Next, the portions of the substrate 21 not covered with chromium, that is, the coating (not shown) on the bottom surface of the fine grooves 20, is removed using caustic soda. As a result, as shown in FIG. 3, an auxiliary layer 22 is formed on the substrate in which the mosaic size is 20 to 50 μm, the thickness is 50 μm, and the groove width formed by the cracks is 1 to 2 μm. be done. Next, when the substrate subjected to the above treatment is plated with metal, for example, gold plating, the gold is preferentially deposited in the fine grooves 20, and the light shielding material 24 defines the auxiliary layer 22. The height of the light shielding material 24 is
It can be easily precipitated to the same level or slightly higher than the auxiliary layer (Figure 4). After the above treatment, the substrate is subjected to anodic electrolysis in a bath containing 500 to 1000 cc of phosphoric acid and 100 to 500 cc of triethanolamine at a bath temperature of 65 to 95°C to form the auxiliary layer 2.
Step 2 is to remove the deposited chromium. After removing the auxiliary layer, rinse thoroughly with water. After completing the steps up to this point, the board is made of aluminum 21 with approximately 50
A light shielding wall 25 with a height of μ is formed, and the light shielding wall 25 is
The size of the small chamber 26 surrounded by 5 is 20 to 50μ
The height is approximately 50μ (Figure 5). A cesium iodide phosphor is deposited on a substrate with such a surface structure at a substrate temperature of 80 to 150°C and a deposition rate of 0.5 μ/min or more.
Deposit a thickness of 150μ. The cesium iodide phosphor layer 27 formed under these conditions covers the light shielding wall 2.
The small chamber 26 surrounded by 5 is filled. It is preferable that the thickness of the phosphor layer 27 is higher than that of the light shielding wall 25. Next, a thin aluminum oxide film is formed as a protective layer 28 to a thickness of 0.01 to 1 μm, for example, 0.05 μm. A photocathode 29 is formed on the protective layer 28 and serves as an input screen (FIG. 6).

In the input screen formed by the manufacturing method described above, it is easy to form fine chambers 26 separated by light shielding walls 25 through the auxiliary layer 22, and the phosphor filled in the chambers 26 can be easily formed. In the layer 27, the light shielding wall 25 prevents the emitted light from spreading in the lateral direction, resulting in improved resolution.

In the above embodiment, the case was described in which chromium was deposited, but after the auxiliary layer 22 having a mosaic structure was formed by depositing nickel, manganese, etc., the grooves 20 of the auxiliary layer were filled with another metal 24. Furthermore, it is possible to form a light shielding wall 25 by removing the auxiliary layer 22. Furthermore, if zircon or the like is previously deposited on the aluminum before depositing chromium, the deposition of chromium becomes much easier.

As described above, the method for manufacturing a fluorescent surface of the present invention is easy to manufacture, allows the height of the light shielding wall to be set at any desired height, and can form extremely narrow light shielding walls with good reproducibility. Since the size of the small chamber divided by the light-shielding wall is extremely small, 20 to 100 μm, the blocks of the phosphor layer formed correspondingly are also small, making it possible to provide a high-resolution input screen. .

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the input phosphor surface of a conventional X-ray fluorescence multiplier tube, FIG. 4 and 5 are cross-sectional views for explaining the manufacturing method according to the present invention, and FIG. 6 is a diagram showing an example in which the fluorescent surface according to the present invention is applied to the input fluorescent surface of an X-ray fluorescence multiplier tube. It is. 21... Substrate, 27... Fluorescent layer, 22... Auxiliary layer,
29...Photocathode, 25...Light shielding wall.

Claims (1)

[Claims] 1. A step of forming an auxiliary layer of a mosaic structure on the surface of the substrate, a step of filling a light shielding material into the grooves that partition the mosaic structure, and a step of removing the mosaic portion leaving the filling material and filling the surface of the substrate. A method for manufacturing a phosphor surface, comprising the steps of forming a light shielding wall with a substance, and forming a phosphor layer on the substrate, wherein the auxiliary layer of the mosaic structure on the surface of the substrate is formed by a plating method. A method for manufacturing a fluorescent surface, characterized in that it is formed by.