JPS61253747A - Electron gun composition for image pickup tube - Google Patents

Abstract

PURPOSE:To enable to fix a ceramic ring while avoiding damage and the like of the ceramic ring, by furnishing a metallic ring of a nonmagnetic metal at the outer peripheral surface of the ceramic ring which is installed to a cylindrical electrode, covering the outer peripheral surface of the metallic ring with a mesh electrode holder, and welding to fix them. CONSTITUTION:At the outer peripheral surface of a ceramic ring 4 which is fixed to a cylindrical electrode 1, a metallic ring 7 made of a nonmagnetic metal such as a stainless metal is installed and fixed. The outer peripheral surface of the metallic ring 7 is covered with a mesh electrode holder 5, the side of which is fixed by resistant-welding or laser welding at its plural portions adequately shown as B in the figure. In this case, the shrinkage fit can be applied to fix the metallic ring 7 to the ceramic ring 4.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an electron gun assembly for an 8A magnification tube, and particularly relates to a mesh electrode support structure for holding a mesh electrode.

[Background of the invention]

For image pickup tubes, prevention of abnormal phenomena such as flicker-1 ripples,
To improve signal uniformity and resolution uniformity across the entire image plane and reduce image distortion, adjust the trajectory of the electron beam so that it is approximately perpendicular to the photoconductive surface within the scanning area. Equipped with a sulcollimation lens.

FIG. 1 is a sectional view of a main part showing a support structure for a collimation lens section of a conventionally used image pickup tube electron gun. In the figure, in the case of an electromagnetic focusing type image pickup tube, 1 is a cylindrical electrode which normally serves as a third grid, and is arranged so that its upper end face faces the lower end face of a mesh electrode 2. Mesh electrode 2
The mesh ring 22 is made of copper mesh 21 with a fine pitch of K100 to 2000 mesh so as not to impair the image quality.
It is sandwiched between the 7-rank part and the ring plate 23, and is constructed by welding at multiple points at approximately equal intervals on the circumference.

In the above configuration, when the image pickup tube is operated, the cylindrical electrode 1 is
The applied voltage Ea is (0,5 to 0.8)XEm to form a collimation lens, so the upper end surface of the cylindrical electrode 1 and the lower end surface of the mesh electrode 2 are insulated and supported coaxially in parallel with a predetermined interval. There is a need to.

In order to prevent this, conventional methods have been to wrap a metal ribbon 3 around the outer periphery of the cylindrical electrode 1 at a predetermined position from the end face of the cylindrical electrode 1 and weld it, insert the ceramic ring 4 until it touches the metal ribbon 3, and then attach another metal ribbon 3 to the ceramic ring. The ceramic ring 4 is fixed by wrapping it around the cylindrical electrode 1 while pressing the ring 4 in between and welding it. On the other hand, the mesh electrode support 5 has a plurality of protrusions 51 on its inner periphery, and after covering the ceramic ring 4 fixed to the cylindrical electrode 1, the mesh electrode support 5 has an end protruding from the end surface of the ceramic ring 4. As shown by A in the figure, the part is bent at a plurality of locations and caulked to fix it to the ceramic ring 4 (Kiken 1@58-16296).

FIGS. 2 and 3 show a conventional caulking method for this mesh electrode support 5. Figure 2 shows an example in which caulking is performed by pushing out the caulking punch 6b from the horizontal direction, and Figure 3 shows an example in which caulking is performed by applying pressure from the vertical direction with the caulking punch 6b.
In either case, if caulking is performed with strong pressure, the end of the ceramic ring 4 will be damaged, such as chipping, and if the broken pieces adhere to the photoconductive surface, it will cause non-serious defects in the performance of the image pickup tube, resulting in a defective product. . In addition, if the soft crimping pressure to avoid damage is weak, the mesh electrode support 5 will not be sufficiently fixed to the ceramic ring 4, and the end of the cylindrical electrode 1 will be damaged when shock or vibration is applied from outside the image pickup tube. A misalignment occurs in the collimation lens constituted by the mesh 21 and the end of the mesh 21, causing inconveniences such as a longer time for the microphony phenomenon due to the vibration of the mesh 21 which causes distortion in the image height, and impairing the performance of the image pickup tube. There was a drawback.

[Purpose of the invention]

The present invention was made in view of the above circumstances, and its purpose is to prevent damage such as chipping of the ceramic ring, and to easily fix the mesh electrode support by welding. An object of the present invention is to provide an electron gun assembly for an image pickup tube that can be firmly fixed to an image pickup tube.

[Summary of invention O]

In order to achieve the above objects, the present invention provides a metal ring made of a magnetic metal material on the outer surface of a ceramic ring that is combined and fixed to a cylindrical electrode, and a mesh electrode support is covered on the outer peripheral surface of this metal ring. By welding the sides thereof, the cylindrical electrode and the mesh electrode support are insulated and fixedly arranged.

[Embodiments of the invention]

Next, embodiments of the present invention will be described in detail using Examples.

FIG. 4 is a cross-sectional configuration diagram of essential parts showing an example of an electron gun assembly for an image pickup tube according to the present invention), and the same parts as in the previous figures are given the same reference numerals. In the same figure, a metal ring T made of a cylindrical body made of a non-magnetic metal such as stainless steel is fixedly arranged on the outer peripheral surface of a ceramic ring 4 fixed to a cylindrical electrode 1. is covered with a mesh electrode support 5, and its side surface is fixed by resistance welding or laser welding at a plurality of locations as indicated by B in the figure.

Here, as a method for fixing the metal ring 7 to the ceramic ring 4, there is a shrink fitting method.
Stainless steel material with a linear expansion coefficient of 150 to 200XIO/'C at °C and a linear expansion coefficient of 30 at 20 to 800 °C
For example, a stainless steel ring with a linear expansion coefficient of 180 x 10-7 is heated to about 500°C to expand, and then a room temperature ceramic ring with a linear expansion coefficient of 50 x 10/'C is inserted. Then, cool it to room temperature and fix it. In this case, when the stainless steel ring is cooled to room temperature, the stainless steel ring contracts and presses the ceramic ring, but it is possible that the ceramic ring may be damaged by pressing too much.

Therefore, at least one
The structure is such that these protrusions usually press down on the ceramic ring. Here, if the stainless steel ring were to shrink too much, the protrusion mentioned above would be crushed, so fix the stainless steel ring while avoiding damage to the ceramic ring due to excessive pressure. It becomes possible to do so.

〔Effect of the invention〕

As explained above, according to the present invention, a metal ring made of a magnetic metal material is provided on the outer peripheral surface of a ceramic ring that is fixed in combination with a cylindrical electrode, and a mesh electrode support is placed on the outer peripheral surface of this metal ring and fixed by welding. As a result, the ceramic ring can be easily fixed while avoiding damage, etc., and the mesh electrode support can be fixed and arranged sufficiently firmly, greatly improving the performance of the image pickup tube. An extremely excellent effect can be obtained.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing the support structure of the collimation lens part of the image pickup tube electron gun, FIGS. 2 and 3 are cross-sectional views showing the conventional caulking method for the mesh electrode support, and FIG. 4 is the imaging method according to the present invention. It is a cross-sectional configuration diagram of essential parts showing an example of a tube electron gun structure. 01...Cylindrical electrode, 2...Mesh electrode, 4...φ ceramic ring, 5...Mesh electrode support, 7 ...Metal ring.

Claims (1)

[Claims] In an electron gun assembly for an image pickup tube in which a cylindrical electrode and a mesh electrode support are disposed on the same axis with a ceramic ring interposed therebetween, a magnetized metal ring is fixedly arranged on the outer peripheral surface of the ceramic ring, and the An electron gun assembly for an image pickup tube, characterized in that a magnetic metal ring and a mesh electrode support are welded and fixedly arranged.