JPS6047346A - Electron gun - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electron gun, such as one used in an image pickup tube.

To construct an electron gun, the parts of the electron gun (e.g.
(one or more gratings and cathodes) are first positioned on the axis and then pushed together. Next, melt f, +1
Three strips of steel IJ are attached lengthwise to the parts and allowed to harden to hold the parts together.

However, glass is brittle and may break, and is not rigid enough to prevent deformation. Additionally, if the electron gun is unsatisfactory, the components used in the gun cannot be corrected. This is because only Kokichi can easily cut the glass without damaging the available parts.

Once the parts are damaged, they cannot be subsequently realigned.

These drawbacks are particularly significant for electron guns used in small image pickup tubes. (If three crow strips are used, these are required.) The IJ tube must be thin enough to fit into the image tube, but the rigidity of the strips is very low, making it difficult to keep the grating and cathode precisely aligned. There is a strong tendency for it to be broken. Because of the tolerances that must be met in the manufacture of the grid and cathode, it is particularly desirable that components used in small image tubes be able to be reused if the electron gun proves unsatisfactory during testing.

One method proposed so far to reduce these drawbacks is to use two large pieces of glass that almost completely surround the part to be positioned. (Shizu) Beshita et al.
Parts are still not salvageable, fragility is still a problem, and two pieces of glass are less stable than three pieces. This makes the kind of access needed to do further work inside the image tube very difficult.

It is an object of the present invention to reduce or eliminate these difficulties.

According to a first aspect of the invention, the element is positioned 16 by means including an elongate member extending through an aperture in the element, the elongate member having two a holder is provided, the holder being initially free relative to the elongated member, in order to hold said element in the desired position;
An electron gun is provided that is fixedly positioned on the elongate member in contact with the element. The element may be a grid-like component or a support for a grid or cathode-like component. The parts can thus be recovered by simply removing one of the holders. The elongated member is preferably a flexible wire that is tensioned to hold the element in place with sufficient rigidity. A single member passing through a hole in each of the several elements may be used to position the several elements. Also, to provide stability, multiple members are used distributed around the edges of the element.

Preferably, the retaining body is located between the end piece and the element and has at least one hole passing through said member.
It consists of two spacers. The members, end pieces, elements and spacers thus form columns. Preferably, the end piece is held in place by an element that secures it to the member itself.

If the elongated member is a wire and the part of said element through which this wire passes is electrically conductive, preferably 1,41 is a tubular electrical insulator passing through the hole in the element and the hole in said at least one spacer. surrounded by Thus, if a column contains multiple elements, these elements may be at different potentials. The insulator is preferably made of ceramic like the spacer.

According to a feature of the invention, the image pickup tube has an electron gun as described in -.

According to a second aspect of the invention, a method for positioning an element of an electron gun includes passing an elongate member through a hole in the element, sliding a holder having a hole over the member on each side of the element, and applying tension to the member. Additionally, it includes contacting the holder and the element and then fixing the holder in that position.

The present invention will be further described with reference to the accompanying drawings.

Referring to No. 11>4+, the electron gun of the image pickup tube is surrounded by a glass cover (not shown) and has an electron tube glass space 1 fi 1-, with several bottles 2 passing through this base j. . Pin 2 forms the electrical connection between the various parts of the electron gun and the power supply outside the glass envelope.

A cathode 3 is placed inside the electron gun, and this cathode 3 is connected to a cathode heater 4.
is heated to generate an electron beam. The electrons are heated by the grating 5 and sent through a cylindrical focusing assembly 6 to a target (not shown).

The cathode 3 and the grid 5 are each held in place by elements 7.8. The element 7 consists of a cylinder surrounding the cathode 3, the cylinder having a flange 4 around its base. Element 8 consists of a metal plate and is positioned at a distance from element 8 by grid 5 (J ceramic ring 9).

Element 7.8 has at its edges three columns 10.11.
having an extension forming part of the first. 3 in IZI
Only two of the book's columns are shown.

Three columns 10.11.12 are equally spaced around the elements 7.8 as shown in FIG. 2 and hold them in place. Another element 13 forms part of column 10.11.12.

Element 13 is a cylindrical body with a flange at its base and fits inside the base of focusing assembly 6 to form column 10.1.
1.12, thus fixing the two elements 7.8 in place.

One of the three columns 10 is shown in FIG.

Elongated IL material or wire 14 forms the central core of column 10 and is surrounded by an electrically insulating ceramic tube 15. Each element 7.8.13 has three holes in its edge, through which the ceramic tube 15 passes. The holes are only slightly larger than the diameter of the ceramic tube 15 to improve the fit. Element 7.8.13 is an electrically insulating ceramic spacer 16.17.18.1 constituting the holder.
They are separated from each other by 9. Element 7.8.13 and ceramic spacer 16.17.18.19 are held in two holders or metal end pieces 20.21 at each end of column 10. The other columns 11, 12 have a similar structure.

Korat 10.11.12 fitted wire 14 ceramic tube 15, element 7.8.13 and ceramic spacer 16
．． 17, 18, 19 are assembled by sliding them into position on the tube 15.

An end piece 20.21 is then attached to each end of the column 10.11.12. Tension the wire and bring the end piece 20.21, spacer 16.17.18.19 and element 7.8.13 into contact with each other. Once the columns 10.11.12 are properly aligned, the end pieces 20.21 are spot welded in place to form the rigid structure 4.

The line forming the central core of the corato 12 extends to form an electrical contact between a portion of the focusing assembly 6 and the pin 2 of the electron tube base 1. The lines of the other column 10.11 extend from the base of the column and are bent under the cathode assembly to form the support 22.23 of the cathode heater 4.

[Brief explanation of drawings]

FIG. 1 is a partial cross-sectional view of an example of an electron gun and a small image pickup tube according to the present invention, FIG. 2 is a cross-sectional view taken along the IT-TI line in FIG. 1, and FIG. 3 is a part of FIG. 1. FIG. 7.8.13... Element, 14... Elongated member, 16.17.18.19.20.21... Holder. Su11

Claims (1)

Claims: (1) positioning the element by means including an elongated member extending through a hole in the element;
The material is provided with two retainers, one on each side of said element, the retainers being initially free relative to said elongate member, but in order to hold said element in the desired position, said retainer is The electron gun is fixedly positioned in contact with the element. (2) The retainer comprises an end piece and at least one spacing hole positioned between the end piece and the element and having a hole 4 passing through the member.
Electron gun described in section. (3) The electron gun according to claim (2), wherein the at least one spacer is an electrical insulator. (4) The electron gun according to claim 1, (2), or (3), wherein the elongated member is a flexible wire. (5) The electron gun through which the wire passes. parts of the element are conductive;
Electron gun according to claim 4, wherein the wire is surrounded by a tubular electrical insulator passing through the hole in the element and the hole in the at least one spacer. (6) The element is positioned by means comprising three elongate members equirVJ spaced at the edge of the element and their respective holders. ) according to claim 6, comprising a plurality of elements, each of which has three holes through which the respective elongated member passes. Electron gun. (8) An imaging tube having an electron gun as described in any one of claims (1) to (7). (9) Passing the elongated member through the hole in the element, sliding a holder having a holder on each side of the element over said member, tensioning said member to bring the holder and element into contact, and then fixing the holder in that position. A method of positioning the elements of an electron gun, including: