JPS59166682A - Intra-tube part - Google Patents

Abstract

PURPOSE:To obtain an intra-tube part of high strength, by providing chromium oxide converted from a chromium compound with heat on the surface of an Invar alloy substrate for the intra-tube part. CONSTITUTION:A substrate is an intra-tube part comprising an Invar alloy to be used in an electron gun. Said substrate is dipped in a solution of specific gravity of 1.6-1.7 containing chromic acid as a main component and then heat treated. This cycle is repeated several times, while gradually raising the temp. within the range of a heating temp. of 310-700 deg.C. As a result, a dark green chromium oxide layer is formed on its surface. When said intra-tube part is used as a shadow mask or a frame, it has sufficient strength as the shadow mask so that no deformation is formed even after attaching and detaching it several times in the step of incorporating it in a cathode-ray tube.

Description

[Detailed description of the invention] (Technical field of invention) The present invention relates to tube internal parts used in electron tubes.

(Technical background of the invention and its problems) In a shadow mask type picture tube, the shadow mask reproduces a color image by irradiating a predetermined phosphor dot with an electron beam emitted from an electron gun through a number of openings. It is intended to help people achieve this goal, and it plays an extremely important role. However, at this time, not all of the electron beams pass through the aperture, so the shadow mask is heated by the electron beams that do not pass through the opening. As a result, the position of the opening shifts due to thermal expansion.

There is a risk of color shift.

To prevent this, the conventional method has been to support the shadow mask with a bimetal and use the curvature of the bimetal due to heat to bring the shadow mask closer to the phosphor surface to prevent color shift.

2. If the thermal expansion coefficient of the shadow mask were sufficiently small, this troublesome process could be avoided, and an attempt has been made to form the shadow mask itself from an invar alloy with the smallest thermal expansion coefficient.

However, the mechanical strength of the two conventional shadow masks was not sufficient.

That is, the shadow mask is usually 0.1 yarn to 0.1 yarn.
Since it is formed from two thin plates and has a large number of holes, it cannot maintain an accurate shape if its mechanical strength is low. Furthermore, the shadow mask is attached to and detached from the cathode ray tube several times until the cathode ray tube is completed.1 If the mechanical strength is insufficient, the shadow mask may become deformed due to repeated attachment and detachment, and may become misaligned with respect to the predetermined phosphor screen. This could sometimes occur.

(Objective of the Invention) An object of the present invention is to provide a highly strong internal pipe component suitable for, for example, a shadow mask and a mask holder.

(Summary of the Invention) The pipe internal component of the present invention is characterized in that the surface of the base is provided with chromium oxide, which is converted from a chromium compound by heating.

The chromium compound is preferably impregnated or chemically bonded to the substrate. In this case, the chromium compound is in liquid form, chromic acid, chromium chloride.

A material containing chromium nitrate or magnesium chromate as a main component, and a material containing a soluble complex chromium compound as a main component can be used. In addition.

Contains zinc oxide, guic acid, aluminum oxide, etc. as necessary.

The base material is an invar alloy with low thermal expansion (Ni25~50
% iron alloy) is preferred, but mild steel, which has been conventionally used as a shadow mask, may also be used.

To obtain the pipe inner part of the present invention 2 For example, the pipe inner part set in a predetermined shape is immersed in a reaction solution containing a chromium compound as a main component, and then heat-treated to convert it into a layer containing chromium oxide. . A desired surface condition is obtained by repeating this cycle multiple times. It is effective to previously perform surface treatment 2 such as plating, thermal spraying, etc. on the inner parts of the pipe before impregnation.

The tube internal parts thus obtained have improved springiness due to the two surface layers and good wear resistance, so there is little dimensional deterioration due to attachment and detachment from pins during the process.

In addition, there is little sagging due to heat treatment, etc. Also, the obtained surface layer exhibits a dark green color and has good heat absorption.

(Embodiment of the Invention) After casting an iron alloy containing 36% Ni, it was forged and hot rolled to a thickness of 4 to 10 mm, and then hot rolled to a plate material of 0.15 m++ thickness. At this time, a plate material was obtained by appropriately inserting annealing in the intermediate process. This plate material was subjected to the following treatments.

After the plate material is immersed in a solution mainly composed of chromic acid with a specific gravity of 1.6 to 1.7, it is heat-treated.

This cycle was repeated multiple times (3 to 10 times) while gradually increasing the heating temperature from 310° to 700°C.

As a result, a dark green chromium oxide layer was obtained on one surface.

The obtained plate material has improved mechanical strength (hardness) and a coefficient of thermal expansion that is not so large (15 to 30 x 10-
7/℃).

(Effects of the Invention) When used as a shadow mask or frame, the tube internal component of the present invention has sufficient strength as a shadow mask and will not be deformed even if it is attached and detached multiple times during the process of assembling it into a cathode ray tube.

In addition, the spring properties are improved, and the tendency to set due to heating is reduced, so that the action can be made stable and uniform.

Representative Patent Attorney Noriyuki Chika (1 other person)

Claims (2)

[Claims] (1) Pipe inner parts with chromium oxide converted by heating from Chrome Kitakanamono on the surface of the base. (2) The pipe internal component according to claim 1, wherein the base body is an invar alloy.