JPS5810345A - Formation of metallic film for image pickup-tube deflecting electrode - Google Patents

Abstract

PURPOSE:To reduce hours taken for vapordeposition work so as to increase the productivity, and enable a metallic film with a sufficient thickness to be homogeneously formed on the inner wall of a glass tube by vacuum vapordeposition by installing a metal-powder evaporating source within the glass tube, and heating the glass tube from its outside while rotating the tube. CONSTITUTION:The symbol 15 represents a glass tube placed with its tubular axis corresponding to the lateral direction. The symbol 16 represents a vapordeposition mask, the symbol 20 represents a tungsten boat which is horizontally placed in the glass tube 15, the symbols 21 represent current terminals which support both ends of the tungsten boat 20, and the symbol 22 represents chromium powder provided within the tungsten boat 20. The symbols 23 represent rollers which support the glass tube 15 on their circumference surfaces and rotate the tube 15 around the axis of the tube 15, and the symbols 24 represent heaters provided under the tube 15. When the tube 15 is heated with the heaters 24 while being rotated with the rollers 23 and a current is fed between the terminals 21, the chromium powder 22 vaporizes, and a chromium film with a sufficient thickness is homogeneously formed on the inner wall of the tube 15 by vapordeposition.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for forming a thick metal film for a deflection electrode on the inner surface of a glass tube of an image pickup tube.

FIG. 1 is a cross-sectional structural diagram of an image pickup tube. In the figure, 1 is a face plate made of a transparent glass substrate, 2 is a transparent conductive film made of 5nOz or the like formed on the inner surface of the face plate 1, and 3 is a photoconductive film formed on the inner surface.
The area around these faceplate assemblies is indium 4
is sealed to the open end of the glass tube 5 through the indium 4
A signal electrode 6 for extracting signals from the transparent conductive film 2 is provided on the outer periphery of the transparent conductive film 2.
is provided. 7 is an electron gun assembly built into the glass tube 5, 8 is a deflection electrode formed on the inner surface of the glass tube 5, and the inside of the glass tube 5 is airtightly evacuated. Subject 9
The incident light 10 forms an image on the photoconductive film 3 through the optical lens system 11, and a charge pattern corresponding to the image of the subject 9 is formed on the photoconductive film 3. The electron beam 12 emitted from the electron gun assembly 7 passes through a focusing coil 13 arranged around the outer periphery of the glass tube 5 . It is focused by the magnetic field created by the alignment coil 14 and deflected by the deflection electrode 8 to scan the surface of the photoconductive film 3. By scanning the electron beam 12, the charge pattern is converted into an electric current, and the transparent conductive film 2. The signal is extracted from the signal electrode 6 through the indium 4 as an electric signal to the outside of the tube.

Here, the deflection electrode 8 is obtained by depositing metal chromium or the like on the inner surface of the glass tube 5, and then forming the deposited film into a predetermined shape by laser beam processing. In order to vacuum-deposit such a metal film inside a glass tube, the glass tube must first be heated, and the deposition must be carried out while being heated to about 200° C. or higher.

FIG. 2 is an explanatory diagram of a conventional method for forming a metal film for a deflection electrode. 15 is a glass tube arranged with the tube axis in the vertical direction; 1
6 is an evaporation mask; 17 is a chromium-plated tungsten wire that serves as an evaporation source and is disposed within the glass tube 15 so as to be substantially aligned with the central axis; 18 is a current terminal that supports both ends of the tungsten wire 17; and 19 is a glass tube 15. This is a coil heater placed so as to surround the outside of the The glass tube 15 is heated by the coil heater 19, and a current is passed between the current terminals 18 to heat the tungsten wire 17 to evaporate and deposit chromium.

However, with this method, since the glass tube must be placed inside the coil heater, it takes time and effort to attach and detach the glass tube, which is the object to be deposited, resulting in poor production efficiency. . In addition, the substance to be evaporated (metallic chromium, etc.) is coated on the evaporation source in advance by plating, etc., but there is a limit to the amount that can be coated by plating, etc., so the thickness of the evaporated film must be made to be more than a predetermined thickness. For example, it is difficult to apply a coating, which makes production difficult.

The present invention aims to eliminate these conventional drawbacks, and its purpose is to develop a metal film for image pickup tube deflection electrodes that can be vacuum-deposited to a sufficient thickness on the inner surface of a glass tube in a short period of time. The object of the present invention is to provide a forming method.

FIG. 3 is an explanatory diagram of a method for forming a metal film for a deflection electrode according to the present invention. 15 is a glass tube arranged with the tube axis in the horizontal direction;
16 is a vapor deposition mask, 20 is a tungsten board placed horizontally inside the glass tube 15, 21 is a current terminal that supports both ends of the tungsten boat 20, 22 is a chromium powder provided inside the tungsten boat 20, and 23 is a glass A roller 24 that supports the tube 15 on its circumferential surface and rotates it around the tube axis is a heater disposed below the glass tube 15. When the glass tube 15 is heated by the heater 24 while being rotated by the roller 23, and a current is passed between the current terminals 21,
The chromium powder 22 is evaporated, and a chromium film is deposited uniformly and to a sufficient thickness on the inner surface of the glass tube 15.

According to this method, the fragile glass tube can be installed in a stable state in the lateral direction, the heater can be used continuously once installed, and the evaporation source material can be easily replenished. Furthermore, the glass tube does not need to be placed inside the heater as in the conventional case, but can simply be placed on the rotor, which simplifies the work.

As described above, according to the present invention, the time required for the vapor deposition operation is shortened, productivity is increased, and the metal film can be uniformly vacuum-deposited to a sufficient thickness within the glass tube.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional structural diagram of an image pickup tube, FIG. 2 is an explanatory diagram of a conventional method of forming a metal film, and FIG. 3 is an explanatory diagram of a method of forming a metal film of the present invention. s, is-...0 glass tube, 4 pieces 8 φ... deflection electrode,
16@...Vapor deposition mask, 20...++9 tungsten boat, 21...Current terminal, 22...Chromium powder, 23...Roller, 24...ψ heater.

Claims (1)

[Claims] For image pickup tube deflection electrodes, a metal powder evaporation source is installed inside a glass tube arranged with the tube axis in the horizontal direction, and the glass tube is heated from the outside while rotating to deposit a metal film on the inner surface of the glass tube. Method of forming metal film.