JPH09259761A - Manufacture of cathode-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain the occurrence of a microcrack by a metallic band to the possible minimum level in an envelope (a face panel) by forming a through hole part to prevent contact with a mold match line, and installing the lugs in a part except a corner part of the metallic band. SOLUTION: In a cathode-ray tube which has an implosion preventive metallic band 4 fastened to a bending skirt part 1b on the funnel side from a display surface part of a face panel 1A to constitute an envelope and in which lugs 5 supported with a casing of an image receiver are installed on this metallic band, a through hole part 6 to prevent contact with a mold match line formed in the skirt part 1b in its corner part, is formed in the metallic band 4, and the lugs 5 are installed in a part except the corner part of the metallic band 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a cathode ray tube, for example, a method of manufacturing a cathode ray tube in which a metal band for implosion prevention is attached to the envelope before heating and exhausting the envelope. Regarding the method.

[0002]

2. Description of the Related Art A cathode ray tube is manufactured through a process of exhausting gas in the tube by heating its envelope to about 400 ° C. in a heating and exhausting furnace in the manufacturing process.

In this case, as the cathode ray tube itself becomes larger and the display portion becomes flat, a metal band for preventing the destruction or implosion of the envelope (hereinafter, simply referred to as a metal band if necessary). (Sometimes called) may be attached before the work of heating and exhausting the envelope.

This is extremely effective in preventing damage during quenching (25 ° C.) when the envelope is taken out from the heating / exhaust furnace by attaching a metal band before heating / exhausting the envelope. It is known that

Here, the envelope has a face panel on the display surface side, a neck containing an electron gun arranged to face the display surface, and a neck for connecting the face panel to the neck. The metal band is formed of a funnel, and the metal band is a portion bent from the display surface portion of the face panel to the funnel side, and is fastened to a so-called skirt portion. This is because stress is concentrated in the skirt portion after exhausting, which easily causes destruction of the envelope or implosion.

Incidentally, such a technique is described in detail in, for example, Japanese Patent Laid-Open No. 62-5533.

[0007]

However, in the cathode ray tube having such a structure, since the display panel side and the skirt portion of the face panel are formed by two different dies, they are different from each other. 0.2 to 0.3m in height at the so-called mold match line between
It has been pointed out that an adverse effect of forming a protrusion of about m and fastening the metal band on the protrusion is provided.

That is, due to the rapid cooling when taking out from the heating / exhaust furnace, the metal band is displaced relative to the envelope due to the difference in the coefficient of thermal expansion, and the face panel exerts a pressing force particularly on the metal band. A large number of so-called microcracks are generated in the corner portion that receives the strongest force.

Then, it has been found that the microcracks thereafter cause destruction or implosion of the envelope.

The present invention has been made under these circumstances, and an object thereof is to provide a method of manufacturing a cathode ray tube capable of suppressing the generation of microcracks due to a metal band in an envelope (face panel) as much as possible. To do.

[0011]

In order to achieve such an object, the present invention is basically fastened to a skirt portion bent from the display surface portion of the face panel constituting the envelope to the funnel side. Equipped with a metal band for implosion prevention,
Further, in the cathode ray tube in which a lug supported by the housing of the receiver is attached to this metal band, the metal band does not come into contact with the mold match line formed in the skirt portion at its corner portion. And the lug is attached to a portion of the metal band other than the corner portion.

In the thus constructed cathode ray tube, a metal band for preventing implosion, which is fastened to the skirt portion bent from the display surface portion of the face panel to the funnel side, is formed on the skirt portion at the corner portion. A through hole is formed so as not to contact the existing mold match line.

This through hole allows the mold match line to avoid direct pressure applied from the metal band, and suppresses generation of microcracks.

Further, by providing the above-mentioned through hole portion in the metal band, deterioration of mechanical strength against a lug (a lug supported by a casing of a receiver) which has been mounted in the vicinity of that portion so far. But especially,
To prevent this, this lug is attached to the parts other than the corners.

In this case, the attachment of the lug to the metal band is performed by spot welding, which helps to promote the generation of microcracks on the mold match line where the projections on the face panel side at the welding points are close to each other. However, by attaching the lug to a portion other than the corner portion as described above, it is possible to further suppress the generation of the microcracks.

Each of the above effects is particularly remarkable in a cathode ray tube in which a metal band for implosion prevention is attached to the envelope before the work of heating and exhausting the envelope.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the cathode ray tube according to the present invention will be described below with reference to the drawings.

FIG. 1 shows a cathode ray tube according to the present invention,
In particular, the external plan view of the cathode ray tube before the work of heating and exhausting the envelope is shown.

In FIG. 1, there is an envelope 1 for a cathode ray tube. The envelope 1 is made of glass, and is arranged so as to face the display panel and a face panel 1A on the display side of the cathode ray tube. The neck 1C includes the electron gun structure 2 and a funnel 1B connecting the neck 1C and the face panel 1A.

Here, while the funnel 1B and the neck 1C are integrally formed, the face panel 1A is formed separately from them, and the face panel 1A and the funnel 1B are fused by the low melting point glass 1D. As a result, the envelope 1 is configured.

The electron gun assembly 2 includes a stem 2A which closes the insertion opening when the electron gun assembly 2 is inserted into the neck 1C,
An exhaust pipe 2B for exhausting the gas in the envelope 1 is integrally formed.

By fusion-sealing the stem 2A and the neck 1C, the electron gun assembly 2 is fixedly arranged at a predetermined position with respect to the neck 1C.

The face panel 1A is provided with a flat portion 1a which is flattened in a portion which becomes a display surface of the cathode ray tube, and the funnel 1B extends from the outer periphery of the flat portion 1a.
It is provided with a skirt portion 1b that bends and extends to the side.

The skirt portion 1b is fastened with a metal band 4 for preventing implosion covering the periphery thereof via a glass cloth tape 3 and is fastened to the skirt portion 1b in the vicinity of the corner portion of the receiver. A lug 5 supported by the housing is attached.

Here, the glass cloth tape 3 serves as a non-flammable cushioning material, the details of which will be described later.

FIG. 2 (a) is a sectional view taken along line II-II of FIG. 1, and FIG. 2 (b) is a partially enlarged view thereof, wherein the metal band 4 is composed of an annular member covering the skirt portion 1b. The glass cloth tape 3 is interposed between the metal band 4 and the skirt portion 1b.

The skirt portion 1 of this glass cloth tape 3
For example, the glass cloth tape 3 may be wound around b.
Has an auxiliary tape made of cotton attached to both ends or one end in the width direction with an adhesive, and is wound around the skirt portion 1b as it is, and the metal band 4 is fastened to the auxiliary tape. It is designed to be peeled off.

In this case, since the glass cloth tape 3 is made of only a material that does not generate combustion gas or the like in the heat treatment, it contaminates the inside of the exhaust furnace and the cathode ray tube itself during the heating and exhausting process. This has the effect of eliminating such anxiety.

A so-called mold match line 7 is formed in the portion of the skirt portion 1b covered by the metal band 4 as shown in FIG. 3 (a) in which the portion of FIG. 1 is enlarged. . This mold match line 7
Is formed inevitably between the two dies since the face panel 1A is formed by two different dies, and as shown in FIG. 3B, the height is 0.2 to 0. .3
The protrusion 8 having a size of about mm is formed. here,
FIG. 3B shows a sectional view of FIG. 3A taken along a plane parallel to the paper surface.

The metal band 4 covering the mold match line 7 has a through hole 6 at each corner.
Is formed, and the mold match line 7 is positioned substantially at the center of the through hole 6.

By means of the through holes 6, the mold match line 7 can avoid direct pressure applied from the metal band 4, and the generation of microcracks caused by the pressure can be suppressed.

The through holes 6 are formed at the respective corners of the metal band 4 because the metal band is pressed against the skirt 1b due to the difference in the coefficient of thermal expansion when the temperature is lowered during the heating and exhausting process. This is because they concentrate most on the club.

In order to fasten the metal band, the metal band is formed into a frame shape corresponding to the outer peripheral shape and size of the skirt portion 1b, which is heated and expanded to form the skirt portion 1b.
It is made by cooling after fitting into.

That is, due to the displacement of the metal band 4,
The pressurization from the metal band 4 directly acts on the mold match line 7, and it is possible to completely eliminate the adverse effect that microcracks are generated.

In this embodiment, the lug 5 attached to the metal band 4 is formed in the vicinity of the corner, avoiding the corner.

The reason for this is to prevent the supporting force from being directly transmitted at the corner portion when it is supported by the casing of the image receiver (not shown), which allows the metal band 4 to have a through hole. The configuration is such that measures are taken against deterioration of mechanical strength due to the formation of the portion 6.

Further, by mounting the lug 5 in this manner, it is possible to further suppress the generation of microcracks generated on the mold match line 7.

That is, the attachment of the lug 5 to the metal band 4 is performed by spot welding. When the lug 5 is attached to a corner portion (which has been done in the past), the skirt portion 1b side at the welded portion. This is because it has been found that the projections of 1 helped promote the generation of microcracks on the adjacent mold match line 7.

[0039]

As is apparent from the above description,
According to the cathode ray tube of the present invention, it is possible to suppress the occurrence of microcracks in the envelope (face panel) of the implosion-preventing metal band as much as possible.

[Brief description of drawings]

FIG. 1 is an external plan view showing an embodiment of a cathode ray tube according to the present invention.

2 is a cross-sectional view taken along line II-II in FIG. 1 and a partially enlarged view thereof.

FIG. 3 is an enlarged view of FIG. 1 and a sectional view thereof.

[Explanation of symbols]

1A ... face panel, 1b ... skirt part, 3 ...
Glass cloth tape, 4 ... metal band, 5 ... lug,
6 ... Through hole.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hideo Tanabe, 3300 Hayano, Mobara-shi, Chiba Electronic device division, Hitachi, Ltd. (72) Inventor, Akio Nakamura 3300, Hayano, Mobara-shi, Chiba Hitachi, Ltd. Electronic device Within the business unit

Claims (2)

[Claims] 1. An implosion-preventing metal band to which a lug supported by a casing of a receiver is attached, and a face panel of the envelope before heating and exhausting is bent from the display surface portion to the funnel side. In the method of manufacturing a cathode ray tube to be fastened to a skirt part, the metal band is formed with a through hole part at its corner part so as not to contact a mold match line formed in the skirt part, and the lug is formed. Is a method of manufacturing a cathode ray tube, characterized in that the metal band is attached to a portion other than a corner portion. 2. The method of manufacturing a cathode ray tube according to claim 1, wherein the fastening of the metal band to the envelope is performed via a glass cloth tape.