JPS58915Y2 - X-ray image tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an X-ray image tube, and particularly relates to an improvement in the structure of an optical system position adjustment member attached to the X-ray image tube.

An X-ray image tube is an electron tube that converts radiation such as X-rays and γ-rays into visible images.

This X-ray image tube has an input fluorescent surface that converts an X-ray image into a visible image, for example, at one end of the envelope, and a photocathode that emits photoelectrons depending on the strength of the light of this visible image. , a focusing electrode and an anode for accelerating and focusing photoelectrons, and an output fluorescent surface that emits light from the accelerated and focused photoelectrons at the other end of the envelope to produce a visible image thereon.

The visible image appearing on the output fluorescent surface is transmitted onto the film of an X-ray television camera or spot camera by an optical lens placed opposite the output fluorescent surface.
At this time, it is necessary to correctly match the optical axis and parallelism of the output phosphor surface and the optical lens, and this accuracy significantly affects the resolution and shape distortion of the optical image formed on the film of the X-ray television camera or spot camera. influence

FIG. 1 schematically shows the structure of a conventional X-ray image tube equipped with the above-mentioned output fluorescent surface and members that enable adjustment of the optical axis and parallelism of the optical system.

That is, this X-ray image tube 1 is made of glass and includes a cylindrical part 5 which is connected to the enlarged part 3 via a shoulder part 4 and whose end is closed. Although not shown in the drawings, an output fluorescent surface 7 is provided at the end of the cylindrical portion 5 in the vicinity of the input window 2.

In addition, a plurality of screw rods 8, 8 for adjusting the position of the optical system are implanted in the shoulder portion 4 of the envelope 6 of the X-ray image tube 1, parallel to the tube axis and oriented in the direction of the output fluorescent surface 7. Furthermore, an annular support plate 9 to which an optical system is fitted is inserted through the position adjustment screw rods 8, 8.

However, the method of adjusting the annular support plate 9 as a lever will not be described in detail here, but the parallelism and optical axis with respect to the output fluorescent surface 7 can be determined using a dial depth gauge, an optical microscope, etc.
That is, after adjusting the position with respect to the tube axis xx', the nuts 10, 10 .
It is tightened and fixed by 10.

After that, an optical lens 11 is attached to the annular support plate 9, and the position adjustment of this optical lens 11 is performed using the output fluorescent surface 7 described above.
Since the annular support plate 9 and the annular support plate 9 have been adjusted in advance, they can be matched with each other with only a slight adjustment.

In this way, the screw rods 8, 8 have the function of a member for adjusting the position of the optical system.

After the position adjustment of the annular support plate 9 has been completed, the X-ray image tube 1 is housed in a cylindrical casing 14 having an X-ray shielding plate 12 and a magnetic shielding plate 13 attached to the side wall, and is ready for use.

However, in conventional X-ray image tubes with such a structure, the position adjustment screw rod is implanted in the shoulder of the glass envelope as described above, and this is done by heating and melting the shoulder with a gas burner or the like. However, since the post-position adjustment screw rods are manually embedded and welded and fixed, the accuracy of the finished dimensions is extremely poor, making it impossible to make sufficient adjustments.

In addition, the thickness of the glass at the welded portion becomes uneven, weakening the mechanical strength, which may cause damage to the tube during adjustment.

Furthermore, it requires heat treatment to remove distortion after welding, which increases the number of work steps, and has other disadvantages in manufacturing.

Therefore, a proposal for eliminating the inconvenience of installing a threaded rod in the envelope is disclosed in the specification and drawings of Japanese Utility Model Application No. 130653/1983.

In this method, one end of a cylindrical or band-shaped holding member is held by a flange provided on the input surface or body of the tube, and a ring-shaped adjustment plate is screwed to the other end, and an elastic presser ring and this are tightened. It is fixed using a presser screw, and this adjustment plate is provided with a tension rod for position adjustment.

According to this method, manufacturing is easy because no tension rod is installed in the tube envelope, but on the other hand, a cylindrical or band-shaped holding member is provided coaxially surrounding most of the body, and this can be attached to the input surface or The structure is still large-scale because it is tightened and fixed by the flange of the body, the adjusting plate, the retaining ring, and the retaining screw.

In addition, since the adjustment plate equipped with the position adjustment screw that determines the position of the optical system is displaced together by the tightening of the presser screw used to secure it to the tube envelope, it is possible to fix them mutually and adjust their position. It must be assembled in such a way as to satisfy both the positioning of the cap screw, and it is difficult to satisfy both, and it is considered difficult to obtain sufficient mechanical strength and precision in assembly.

The present invention has been developed in view of the above circumstances, and has a simple structure that allows the screw rod for adjusting the position of the optical system to be easily fixed to the tube envelope, and which eliminates the risk of damage to the tube envelope. This provides an X-ray image tube with a reduced number of configurations.

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

That is, FIGS. 2 and 3 schematically show the structure of the X-ray image tube according to the present invention.
Reference numeral 0 is a glass-made vacuum outer part consisting of an enlarged part 22 with a manual window 21 formed at one end, and a small-diameter cylindrical part 24 connected to this enlarged part 22 via a shoulder part 23 and closed at the other end. Enclosure 25
Although not shown in the drawings, there is a human power section 2 located close to the input window 21 of the envelope 25 and consisting of an input fluorescent surface and a photocathode.
6 is provided, and a focusing electrode 27 is further provided on the inner wall of the envelope 25.

On the other hand, a cylindrical anode 2 is provided at the end of the small diameter cylindrical portion 24 made of glass.
8 is provided, and surrounded by this anode 28, an output fluorescent surface 29 is provided.

A holding structure 30 is coaxially arranged on the outer wall surface of the shoulder portion 23 of the envelope 24 of the X-ray image tube 20.

This holding structure 30 has a cylindrical portion 30 as is not clear in FIG.
Subsequently, an annular plate 39 is integrally molded, and the output fluorescent surface 2
Three position adjustment screw rods 31.31.3 pointing toward the 9 side
1 and has an opening 32 in the center thereof for extracting a visible image from the output fluorescent surface 29.

This holding structure 30 is adhesively fixed to the outer wall surface of the shoulder portion 23 so as to surround the small diameter cylindrical portion 24 using an adhesive 33.

Then, screw rods 31.31. for adjusting the position of the holding structure 30.
This threaded rod is inserted through the annular support plate 34.
will be placed.

This annular support plate 34 is adjusted using a dial depth gauge and an optical microscope in the same manner as before to adjust the parallelism to the output fluorescent surface 29 and the position with respect to the optical axis, that is, the tube axis x-x'. It is tightened and fixed by nuts 35, 35, 35.35 which are screwed into 31, 31°31.

The X-ray image tube 20 that has been adjusted in this way is housed in a cylindrical casing 38 having an X-ray shielding plate 36 and a magnetic shielding 37 attached to the inner wall, and is further placed in a position facing the output fluorescent surface 29. An optical lens (not shown) is disposed in the holder for use.

Here, by attaching an X-ray shielding plate made of lead, for example, to the holding structure 30, leakage of X-rays to the output side can be prevented.

In addition, magnetic shielding can be achieved by forming or attaching a magnetic shielding plate made of a magnetic metal such as iron to this holding structure 30, and furthermore, if an X-ray shielding plate and a magnetic shielding plate are installed together, leakage can occur. It is possible to combine X-ray blocking and magnetic shielding.

As described above, the present invention arranges a holding structure in which a plurality of screw rods for position adjustment are provided on an annular plate so that a small-diameter cylindrical part is attached to the outer wall surface of the shoulder part of the X-ray image tube envelope. One part is fixed with adhesive, and this eliminates the welding seen in the X-ray image tube, where the conventional position adjustment screw rod was implanted in the shoulder of the glass envelope. This prevents weakening of the mechanical strength due to uneven glass wall thickness in the tube, thereby eliminating damage to the tube during adjustment.

Further, since no heat treatment is required to remove strain, the working process can be simplified.

Furthermore, it has an extremely simple structure, and the attachment of each position adjustment screw rod to the holding structure and the fixing of this holding structure to the shoulder can be completed to the specified dimensions with high precision using a jig, etc., and fixed. This makes it possible to precisely adjust the parallelism and optical axis alignment between the output fluorescent surface and the support plate.

Furthermore, the holding structure can be attached to the tube with almost no protrusion in the periphery and axial direction, and can be constructed in a convex manner.

As described above, the present invention is extremely significant in manufacturing X-ray image tubes and has great practical value.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view showing a part of a conventional X-ray image tube housed in a housing, and FIG. 2 is a schematic cross-sectional view of the X-ray image tube of the present invention housed in a housing. Figure 3 is a perspective view of the holding structure attached to the X-ray image tube of the present invention. 29... Holding structure, 30... Screw rod for position adjustment, 39... Annular plate.

Claims (1)

[Scope of utility model registration request] An ampulla 22 having an input window 21 at one end;
A vacuum envelope 25 is provided with a small diameter cylindrical part 24 made of glass which is connected to the body via a shoulder part 23 and has an output fluorescent surface 29 at the other end, and the shoulder part 23 of this envelope 25. In an X-ray image tube having a plurality of screw rods 31 for adjusting the position of the optical system integrally fixed in parallel with the tube axis, the envelope 2
A holding structure 30 having an annular plate 39 surrounding the small diameter cylindrical portion 24 of No.
An X-ray image tube characterized in that the plurality of screw rods 31 are fixed to the.