JP2003217488A - X-ray image tube - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an X-ray image tube improved in strength and stiffness of connection between a metal and ceramics. <P>SOLUTION: An X-ray inputted from an input cover 2 is converted into fluorescence by an input board 21 and converted into photo-electrons. The photo-electrons are converged and accelerated by a converging electrode 22 and an accelerating electrode 23 and transformed into a visible light image on an output surface 18 of an output cover 3 to output it to the outside. The vacuum airtightness of a ceramics body 7 and an output-side metal body 8 is kept by brazing of a metal thin film 15 of the ceramics body 7 to a knife edge part at a tip of the metal body 8. Loading such as load or vibration from the outside is directly transmitted to the ceramics body 7 from the output cover 3, so that transmission of the load and the vibration to the thin film 15 for joining the ceramics body 7 to a knife-edge-like sharp part of the metal body 8 raising concerns about strength and stiffness is significantly reduced to improve reliability. <P>COPYRIGHT: (C)2003,JPO

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 provided with an envelope having a ceramic body at least in part.

[0002]

2. Description of the Related Art Generally, X-rays are used for nondestructive investigation of the internal structure of a human body or an object. And
An X-ray image intensifier, which is an X-ray image tube, is used as an apparatus for converting an X-ray intensity distribution of X-rays irradiated on a human body or an object or an X-ray image into a visible light image.

Conventionally, as the X-ray image intensifier of this type, a structure disclosed in, for example, Japanese Patent Laid-Open No. 56-141152 is known. This Japanese Patent Laid-Open No. 56-1
The X-ray image intensifier described in Japanese Patent No. 41152 has an input lid on the input side and an output lid facing the input lid on the output side, and these input lids are provided between the input lid and the output lid. An envelope that holds vacuum tightness is connected together with the output lid.

Further, the envelope is a cylindrical metal body made of metal welded to the input lid on the input lid side and between the input lid and the output lid, and for insulation on the output lid side brazed to the output lid. The cylindrical ceramic body made of ceramics is used, and the metal body and the ceramic body are brazed to each other with the tip of the metal body being sharpened.

Further, the envelope has an input phosphor screen for converting X-rays into fluorescence on the input lid side and a photocathode formed on the input phosphor screen for converting fluorescence generated from the phosphor screen into photoelectrons. An input board is provided, and an output surface for converting the photoelectrons to visible light is provided on the output lid. For convergence and acceleration, the input board and the output surface are electrically insulated from the envelope. An electron lens composed of a single electrode member or a plurality of electrode members is arranged.

Then, the X-rays that have passed through the human body or the object are made incident from the input lid, and the X-rays are converted into fluorescence and further converted into photoelectrons by the input substrate arranged in the envelope. Then, the photoelectrons are converged by the electron lens, reach the output lid, and are converted into a visible light image on the output surface.

[0007]

However, since the X-ray image intensifier has a vacuum inside the envelope, a load due to atmospheric pressure from the outside of the envelope, vibration generated during transportation or product use, etc. However, since the tip of the metal body is made thin and sharp to be joined to the ceramic body, a large addition is added to the metal body, and there is a problem that strength and rigidity may not be obtained.

The present invention has been made in view of the above problems, and an object thereof is to provide an X-ray image tube having improved strength and rigidity of connection between metal and ceramics.

[0009]

According to the present invention, an input lid formed on the input surface side, an output lid formed on the output surface side facing the input lid, and one end of which is connected to the input lid. A tubular metal input side metal body, a tubular metal output side metal body whose other end is connected to the output lid, and a connection between the input side metal body and the output side metal body And a ceramic body made of ceramics, a part of which is connected to either the input lid or the output lid, and an envelope for maintaining airtightness together with the input lid and the output lid. Since it is connected between the input side metal body and the output side metal body and a part of it is connected to either the input cover or the output cover, the input cover or the output cover can be applied to the ceramic body with a force applied in the compression direction. Connected, ceramics Improved strength and rigidity of the connection.

[0010]

DETAILED DESCRIPTION OF THE INVENTION An X-ray image intensifier according to an embodiment of the X-ray image tube of the present invention will be described below with reference to the drawings.

This image intensifier is shown in FIG.
As shown in FIG. 1, a vacuum container 1 that maintains the vacuum tightness inside
The vacuum container 1 has an input lid 2, an output lid 3 faces the input lid 2, and an envelope 4 is formed between the input lid 2 and the output lid 3.

Further, in the envelope 4, from the input lid 2 side toward the output lid 3, the input side metal body 6 of the Kovar material, the ceramic body 7 and similarly the output side metal body 8 of the Kovar material are formed into a cylindrical shape. It is formed by being connected. Each of the Kovar materials has a thickness of about 1.0 to 1.5 mm, and the thickness of the portion connected to the ceramic body 7 is 0.5 mm. In general, the input side metal body 6 is about several hundreds of volts and the output side metal body 8 is about several tens of kilovolts. Since the input side metal body 6 and the output side metal body 8 have a large potential difference, they are insulated by the ceramic body 7. There is.

The input lid 2 has an arcuate cross section bulging outward, and an input lid flange 5 is formed around the entire circumference of the input lid 2. The input lid 2 side of the envelope 4 is provided with an input side metal body 6 having a large diameter on the input lid 2 side and a small diameter on the output lid 3 side. An input side metal body flange 11 having a shape corresponding to the input cover flange 5 is formed on the entire circumference of the input side 2
The input lid flange 5 and the input side metal body flange 11 of the input side metal body 6 sandwich the airtight member 12 and are connected by welding or the like, so that the input lid 2 and the input side metal body 6 maintain vacuum airtightness. Connected.

Further, the tip of the input side metal body 6 on the output lid 3 side is sharply formed in a knife edge shape, and the tip of the input side metal body 6 on the output lid 3 side is the output of the input side metal body 6. It is brazed to a cylindrical ceramic body 7 made of ceramics and having the same diameter as the lid 3 side and containing alumina (Al ₂ O ₃ ).
A metal thin film 13 such as nickel (Ni) or an alloy containing nickel is coated and sintered on the joint portion of the ceramic body 7 to which the input side metal body 6 is connected. A joining material made of an alloy containing silver (Ag) flows into the metal thin film 13 at the tip of the knife edge of the input side metal body 6 using the capillary phenomenon and is brazed at a temperature of 770 ° C. to 830 ° C. But vacuum tightness is maintained.

Further, on the output side metal body 8 side of the ceramics body 7, a protrusion 14 having an inner peripheral side extended to be flush is formed in a circumferential shape, and the output side metal of the ceramics body 7 having no protrusion 14 is formed. The tip of the output-side metal body 8 which is sharply formed in a knife-edge shape on the side of the input lid 2 is brazed to the joint portion of the body 8. Also in this case, a metal thin film 15 such as nickel or an alloy containing nickel is coated and sintered on the joint portion of the ceramic body 7 to which the output side metal body 8 is connected. Similarly, a joining material made of an alloy containing silver is poured into the metal thin film 15 at the tip of the knife edge of the output side metal body 8 by using the capillary phenomenon, and 770 ° C. to 830 ° C.
It is brazed at a temperature of 10 ° C., and vacuum tightness is maintained even at this joint. The brazing temperature is 770 ° C to 83 ° C.
The temperature is not limited to 0 ° C, but may be about 680 ° C.

Around the output-side metal body 8 on the output lid 3 side, an output-side metal body flange 16 is formed over the entire circumference corresponding to the outer peripheral edge of the output lid 3. Then, the output side metal body flange 16 of the output lid 3 and the output side metal body flange 16 of the output side metal body 8 are connected by welding or the like so that the output lid 3 and the output side metal body 8 maintain vacuum airtightness. Connected.

Further, at the tip of the protrusion 14 of the ceramic body 7, a metal thin film such as a plating of nickel or an alloy containing nickel is formed on the basis of molybdenum (Mo).
17 is applied and sintered, and the ceramic body 7 is this metal thin film.
It is in contact with the output lid 3 via 17. The metal thin film 17
Is formed, the protrusion of the ceramic body 7
This prevents the powder 14 from coming out of contact with the output side metal body flange 16 by rubbing against the output side metal body flange 16.

An output surface 18 for converting photoelectrons into visible light is formed substantially in the center of the output lid 3.

Further, the vacuum container 1 has an input substrate formed of substantially the same material as the input lid 2 in the vicinity of the inner surface side of the input lid 2.
21 is provided, and the input substrate 21 has an input phosphor screen for converting X-rays into fluorescence and a photocathode formed on the input phosphor screen for converting fluorescence generated from the phosphor screen into photoelectrons.

Further, between the input substrate 21 and the output surface 18 in the vacuum container 1, a focusing electrode 22 and an accelerating electrode are provided as an electrode member or a plurality of electrode members while being electrically insulated from the envelope 4. An electronic lens 24 composed of 23 is provided.

Next, the operation of the above embodiment will be described.

First, X-rays that have passed through a human body or an object are made incident from the input lid 2 and converted from the X-rays into fluorescence by the input substrate 21 and further into photoelectrons. The converted photoelectrons are converged by the converging electrodes 22 to which different potentials are applied and accelerated by the accelerating electrodes 23, that is, they are converged by the electron lenses 24 of the converging electrodes 22 and the accelerating electrodes 23 and reach the output lid 3. Then, it is converted into a visible light image on the output surface 18 of the output lid 3 and output to the outside.

Next, the operation of the above embodiment will be described.

First, the ceramic body 7 and the input side metal body 6
And the output side metal body 8 and the input side metal body 6 and the output side metal body 8 are brazed by sharpening the tips of the metal body 8 into a knife edge, and thereby the ceramic body 7 and the input side metal body 6 and the output side metal body 8 are connected. Even if the coefficient of thermal expansion differs, the amount of thermal deformation due to the difference in coefficient of thermal expansion is relaxed, and the thin metal films 13 and 15 on the joint surface of the ceramic body 7 are peeled off or the ceramic body 7 itself is damaged by cracking or cracking. To prevent that.

By contacting the projection 14 of the ceramic body 7 with the surface of the output lid 3, a load due to atmospheric pressure is applied from the outside because the inside of the vacuum container 1 is a vacuum, and during transportation or product use. In order to reduce the load and vibration transmitted to the sharp edges of the knife-edge-shaped metal body 6 and the tip of the input-side metal body 6 and the output-side metal body 8 even if affected by the generated vibration, the ceramic body 7 is reduced. By forming the protrusion 14, the strength and rigidity of the ceramic body 7 are improved by the contact between the ceramic body 7 and the output lid 3 by utilizing the compressive strength characteristic of the ceramic body 7. That is, the vacuum tightness of the ceramic body 7 and the output side metal body 8 is maintained by the brazing of the metal thin film 15 of the ceramic body 7 and the knife edge portion of the tip of the output side metal body 8 while the external airtightness The load such as load or vibration is applied from the output lid 3 to the ceramic body 7.
Is transmitted directly to the metal thin film 15 where the knife-edge-shaped sharp portions of the ceramic body 7 and the output-side metal body 8 which are concerned about strength and rigidity are joined, and the transmission of load and vibration is significantly increased. It is reduced and reliability is improved.

Further, in the above embodiment, the protrusion 14 of the ceramic body 7 is located on the vacuum side inside the output side metal body 8, but it may be formed on the outside atmosphere side.

Further, although the projection 14 of the ceramic body 7 is brought into contact with the output lid 3, the same effect can be obtained by bringing it into contact with the input lid 2.

[0028]

According to the present invention, the ceramic body is connected between the input side metal body and the output side metal body, and a part of the ceramic body is connected to either the input lid or the output lid. It is connected to the input lid or the output lid in a state where a force is applied in the compression direction, and the strength and rigidity of the connection of the ceramic body can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view showing an X-ray image intensifier of an embodiment of an X-ray image tube of the present invention.

[Explanation of symbols]

2 input lid 3 output lid 4 envelope 6 Input side metal body 7 Ceramics body 8 Output side metal body

Claims (4)

[Claims] 1. An input lid formed on the input surface side, an output lid formed on the output surface side facing the input lid, and a cylindrical metal input side whose one end is connected to the input lid. A metal body, a cylindrical metal output side metal body having the other end connected to the output lid, and a part connected to the input side metal body and the output side metal body and partly the input lid and An X-ray image tube having a ceramics body made of ceramics connected to any of the output lids, and an envelope for keeping airtightness together with the input lid and the output lid. 2. The X-ray image tube according to claim 1, wherein the ceramic body has a portion connected to the output lid in parallel with the output side metal body. 3. The X-ray image tube according to claim 1, wherein the ceramic body is brazed to the input side metal body and the output side metal body, respectively. 4. The ceramic body is connected through an alloy containing nickel.
The X-ray image tube according to any one of the above.