JPH08129979A - Image intensifier - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide an image intensifier which can obtain good electron focusing accuracy by a simple manufacturing process and which is not adversely affected by internally scattered light. [Structure] X-rays emitted from an X-ray tube 10 and transmitted through a subject B are converted into electrons e ⁻ at an input fluorescent screen 2, and the converted electron lens e ⁻ is reflected on a glass wall surface 3 ′ of a vacuum container 3. It is focused by the electron lens 4 composed of the formed titanium oxide film 4a and the metal plate 4b, collides with the output surface 5, and is output as visible light. On the other hand, on the input phosphor screen 2, a part of the incident X-rays is converted into visible light, but since they are absorbed by the titanium oxide film 4a, the internal scattered light does not adversely affect the captured image.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image intensifier for converting an incident X-ray image or an invisible light ray image used in a medical instrument such as an X-ray image pickup device into a visible light ray image.

[0002]

2. Description of the Related Art An image intensifier converts an incident X-ray image or an invisible light ray image into a visible light ray image and is widely used in medical equipment such as an X-ray image pickup device. Figure 2
1 is a schematic diagram of a conventional image intensifier 11, in which X-rays emitted from an X-ray tube 10 and transmitted through a subject B are converted into electrons e ⁻ at an input phosphor screen 12, and the converted electrons e ⁻ are vacuum. The light is focused along the glass wall surface 13 ′ of the container 13 by the electron lens 14 having a metal plate in an umbrella shape, collides with the output surface 15, and is output as visible light.

Here, a part of the incident X-rays is converted into visible light by the input fluorescent screen 12 and reaches the electron lens 14, but is reflected by the electron lens 14 formed of a metal plate and internally scattered light. Then, the input phosphor screen 12 is returned to again. In this case, unnecessary electrons are generated on the input phosphor screen 12 due to the internal scattered light, which is a factor of lowering the contrast of the captured image. Therefore, conventionally, the metal plate forming the electron lens 14 is blackened to prevent the internal scattering.

On the other hand, as shown in FIG.
In some cases, the metal vapor deposition film 14 'was directly formed on the glass wall 13' of No. 3 as an electrode and used as an electron lens. In such a case, a metal such as chromium or titanium was used as the film material.

[0005]

However, as shown in FIG. 2, in the case where the electron lens 14 is formed of a metal plate, blackening treatment is performed to obtain a photographed image by visible light generated from the input phosphor screen 12. Although it is possible to prevent the deterioration of the contrast of, the metal plate is formed into an umbrella shape and blackened,
Since a process such as disposing on the glass wall surface 3'is required,
The manufacturing process is complicated and the cost is high. Further, since the assembly accuracy is also limited, the accuracy of focusing the electrons generated from the input phosphor screen 12 cannot be increased to a certain level or higher.

On the other hand, as shown in FIG. 3, the vacuum container 1
In the method of directly forming the metal vapor deposition film 14 'as an electrode on the glass wall 13' of No. 3 with a material such as chromium or titanium, an umbrella-shaped metal plate used for the electrode is not required, and thus cost and electron focusing accuracy are improved. From the point of view, it is preferable, but the metal vapor deposition film 1
Since it is impossible to blacken 4 ′ like a metal plate, it is not possible to avoid adverse effects such as reduction in contrast of a captured image due to unnecessary electrons generated by internal scattered light.

The present invention was devised in order to solve these problems, and an image in which good electron focusing accuracy can be obtained by a simple manufacturing process and which is not adversely affected by internal scattered light. The purpose is to provide an intensifier.

[0008]

In order to achieve the above object, the present invention is an image intensifier in which a metal conductive film is formed as an electrode on a glass wall of a vacuum container.
The metal conductive film is formed of one or more materials selected from titanium oxide, aluminum oxide, zirconium oxide, aluminum oxide, chromium oxide, and nickel oxide.

[0009]

The operation of the image intensifier according to the present invention will be described with reference to FIG.

The X-rays emitted from the X-ray tube 10 and transmitted through the subject B are converted into electrons e ⁻ by the input fluorescent screen 2, and the converted electron lens e ⁻ is a glass wall surface 3 ′ of the vacuum container 3.
Which is focused by the electron lens 4 composed of the titanium oxide film 4a and the metal plate 4b formed on
It is output as visible light. On the other hand, on the input phosphor screen 2, part of the incident X-rays is converted into visible light, but since they are absorbed by the titanium oxide film 4a, the adverse effect on the image due to the internal scattered light does not occur.

[0011]

An embodiment of the present invention will be described below with reference to FIG.

FIG. 1 shows an image intensifier 1, an X-ray tube 10 and an object B according to the present invention. Reference numeral 2 denotes an input fluorescent screen, which is mainly formed of cesium iodide and has an incident X-ray intensity. Emits an electron e ⁻ according to Reference numeral 3 denotes a vacuum container, which is usually made of glass and whose inside is kept in a vacuum. Reference numeral 4 denotes an electron lens for focusing electrons generated from the input phosphor screen 2, which is composed of a titanium oxide film 4a and a metal plate 4b formed on the glass wall surface 3 ', and the titanium oxide film 4a and the metal plate 4b are A desired voltage is appropriately applied so as to focus the electrons e ⁻ . The titanium oxide film 4a is formed on the glass wall surface 3'by thermal spraying or vacuum deposition (CVD), and has a function of absorbing visible light. An output surface 5 is formed of a compound such as zinc sulfide and converts incident electron e ⁻ into visible light and outputs it.

When the X-ray transmitted through the subject B enters the image intensifier 1 configured as above,
Electrons e ⁻ are emitted from the input phosphor screen 2 in accordance with the incident X-ray intensity, are focused by the electron lens 4 composed of the titanium oxide film 4a and the metal plate 4b, collide with the output surface 5, and are output as visible light. To be done. In this case, on the input phosphor screen 2, a part of the incident X-rays is converted into visible light and reaches the titanium oxide film 4a formed on the glass wall surface 3 ', but since they are absorbed by the titanium oxide film 4a, There is no adverse effect due to the internal scattered light as in the conventional case.

Thus, according to the present invention, the vacuum container 3
Since the metal conductive film is formed directly on the glass wall of the above, an umbrella-shaped metal plate used for the electrode is not required, and cost and electron focusing accuracy can be improved, and the film material of the metal conductive film is oxidized. Since titanium is used, generation of internal scattered light can be removed in a simple process without blackening treatment, and a good photographed image can be obtained.

In the above embodiments, titanium oxide was used as the film material for the metal conductive film, but the present invention is not limited to this, and titanium oxide, aluminum oxide, zirconium oxide, aluminum nitride, chromium oxide, nickel oxide are used. Any metal conductive film may be used as long as it is formed of at least one of the above.

[0016]

According to the present invention, since the metal conductive film is formed directly on the glass wall of the vacuum container with a material that does not absorb light, such as titanium oxide, an umbrella-shaped metal plate used for the electrodes is unnecessary. At the same time, the blackening process becomes unnecessary. Therefore, cost and electron focusing accuracy can be improved, and further, generation of internal scattered light can be removed by a simple process without performing blackening treatment, and a good photographed image can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an image intensifier according to the present invention.

FIG. 2 is a schematic diagram of a conventional image intensifier.

FIG. 3 is a schematic diagram of an image intensifier.

[Explanation of symbols]

 1 ... Image intensifier 2 ... Input phosphor screen 3 ... Vacuum container 3 '... Glass wall 4 ... Electronic lens 4a ... Titanium oxide film 4b ... Metal Board 5 ... Output surface

Claims (1)

[Claims] 1. An image intensifier in which a metal conductive film is formed as an electrode on a glass wall of a vacuum container, wherein the metal conductive film is made of titanium oxide, aluminum oxide, zirconium oxide, aluminum nitride, chromium oxide or nickel oxide. An image intensifier characterized by being formed of one or more selected materials.