JP2002015689A - X-ray image tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an X-Ray image tube having an improved quality of images, such as contrast or the like, by suppressing generation of a secondary electron in its output section. SOLUTION: In the X-Ray image tube composed of an input section 12 converting an X-Ray image into photoelectron, a converging electrode 13 accelerating and converging the photoelectron converted in the input section 12 and an anode 14, an output section 15 converging the photoelectron into visible light images, and a vacuum envelope 11 containing the input section 12, the converging electrode 13, the anode 14, and the output section 15, a secondary- electron-emission inhibition layer 17 is prepared at the side of capturing the photoelectron of the output section 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray image tube having improved characteristics such as image quality.

[0002]

2. Description of the Related Art An X-ray image tube is an electron tube for converting an X-ray image into an output image such as a visible light image, and is used in medical diagnostic equipment and the like.

Here, a conventional X-ray image tube will be described with reference to FIG. Reference numeral 31 denotes a vacuum envelope, and an input unit 3 for receiving an X-ray image at one end in the vacuum envelope 31.
2 are provided. The X-ray image input to the input unit 32 is converted into an electronic image, for example, photoelectrons, and output from the input unit 32 as photoelectrons. The photoelectrons output from the input unit 32 are supplied to a plurality of electrodes, for example, the first to third focusing electrodes 33 and the anode 3.
The beam is accelerated and focused at 4 and reaches an output section 35 provided at the other end in the vacuum envelope 31. The photoelectrons reaching the output section 35 are converted into an output image, for example, a visible light image, and
6 to the outside.

Next, the structure of the output section 35 of the X-ray image tube will be described with reference to the sectional view of FIG. Reference numeral 36 denotes a glass output window constituting a part of the vacuum envelope 31,
On the output window 36, a fluorescent layer 351 constituting the output section 35 and a metal layer 352 as a metal back layer are formed in order.

[0005]

The output section 35 of the conventional X-ray image tube has a metal layer 352 made of aluminum or the like on the side for capturing photoelectrons. Therefore, when the accelerated and focused photoelectrons reach the output section 35, the metal layer 35
2, and secondary electrons are generated from the metal layer 352.

[0006] As shown by an arrow e1, the secondary electrons are supplied to the input section 3 by the energy at the time of jumping out of the metal layer 352.
Move in two directions. After that, the focusing electrode 33 and the anode 34
, And are captured by the output unit 35 as shown by the arrow e2, and the fluorescent screen 351 of the output unit 35 emits light. In this case, the secondary electrons that fly out of the metal surface 252 are
2 does not have information as an X-ray image to be input. Therefore, the light emitted from the output unit 35 by the secondary electrons becomes extra light, and deteriorates the image quality such as the contrast of the X-ray image tube.

An object of the present invention is to solve the above-mentioned drawbacks, and an object of the present invention is to provide an X-ray image tube in which the generation of secondary electrons in an output section is suppressed and the image quality such as contrast is improved.

[0008]

SUMMARY OF THE INVENTION The present invention provides an input unit for converting an X-ray image into photoelectrons, a plurality of electrodes for accelerating and focusing the photoelectrons converted by the input unit, and converting the photoelectrons into an output image. An X-ray image tube having an output part, and a vacuum envelope accommodating the input part, the plurality of electrodes, and the output part, and a secondary electron emission suppression layer on a side of the output part that captures photoelectrons. It is characterized by having provided.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIG. Reference numeral 11 denotes a vacuum envelope, and an input unit 12 for inputting an X-ray image is provided at one end in the vacuum envelope 11. The input unit 12 is formed, for example, as a spherical surface having a convex surface on the side to which the X-ray image is input. The photoelectrons output from the input unit 12 are accelerated and focused by a plurality of substantially cylindrical electrodes, for example, a focusing electrode 13 and an anode 14, and reach an output unit 15 provided at the other end in the vacuum envelope 11. Output unit 1
The photoelectrons that have reached 5 are converted into an output image, for example, a visible light image, and output to the outside through an output window 16. Further, a secondary electron emission suppressing layer 17 is provided on the side of the output section 15 where photoelectrons are captured.
Is provided.

Next, the structure of the output unit 15 of the X-ray image tube will be described with reference to FIG. Reference numeral 16 denotes an output window made of glass constituting a part of the vacuum envelope 11.
On 6, a fluorescent layer 151 constituting the output unit 15 and a metal layer 152 as a metal back layer are sequentially formed. On the metal layer 152, a secondary electron emission suppression layer 17 coated with a substance that suppresses secondary electron emission such as titanium nitride is provided.

According to the above configuration, the photoelectrons are output from the output unit 1.
5, the secondary electron emission suppressing layer 17
The emission of secondary electrons is suppressed. Therefore, the output unit 15 eliminates extra light emission due to secondary electrons, and the input unit 12
The information of the X-ray image by the photoelectrons output from the device is transmitted to the fluorescent layer of the output unit, and is converted into a visible light image. As a result, a visible light image having good image quality without a decrease in contrast characteristics can be obtained.

In the above embodiment, the secondary electron emission suppressing layer is formed by coating. In this case, the secondary electron emission suppressing layer is formed uniformly, and a good effect of suppressing secondary electron emission can be obtained.

As described above, according to the present invention, the generation of secondary electrons due to photoelectrons reaching the output portion is suppressed, and an X-ray image tube with improved image quality such as contrast can be obtained.

[0014]

According to the present invention, an image having improved image quality such as contrast is provided by suppressing secondary electrons in the output section.
A line image tube can be realized.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram for explaining an embodiment of the present invention.

FIG. 2 is a schematic sectional view for explaining an output unit of the present invention.

FIG. 3 is a schematic configuration diagram for explaining a conventional example.

FIG. 4 is a schematic cross-sectional view for explaining a conventional output unit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Vacuum envelope 12 ... Input part 13 ... Focusing electrode 14 ... Anode 15 ... Output part 16 ... Output window 151 ... Fluorescent layer 152 ... Metal layer 17 ... Secondary electron emission suppression layer

Claims (4)

[Claims] An input unit for converting an X-ray image into photoelectrons, a plurality of electrodes for accelerating and focusing the photoelectrons converted by the input unit, an output unit for converting the photoelectrons into an output image, and the input unit And an X-ray image tube including the plurality of electrodes and a vacuum envelope accommodating the output unit, wherein a secondary electron emission suppression layer is provided on a side of the output unit that captures photoelectrons. X-ray image tube. 2. An output unit comprising: a fluorescent layer and a metal layer sequentially formed on a glass surface of an output unit constituting a part of a vacuum envelope; and a secondary electron emission suppressing layer formed on the metal layer. The X-ray image tube according to claim 1, which is provided. 3. The X-ray image tube according to claim 1, wherein the secondary electron emission suppressing layer is formed by coating. 4. The X-ray image tube according to claim 1, wherein the secondary electron emission suppressing layer is formed of titanium nitride.