JPH1196941A - Glass bulb for cathode-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a glass bulb for a cathode-ray tube having high mechanical strength without increasing the weight of the glass bulb. SOLUTION: In a glass bulb for a cathode-ray tube comprising a substantially rectangular panel part 1, a funnel part 2 continuously joined to the panel part 1, and a neck part 3, a compressive stress layer is formed on an outer surface and on an inner surface of the panel part 1, and a compressive stress value C of the compressive stress layer has a relation, C>=TMAX, to a maximum tensile stress value TMAX generated in the panel part 1 of the evacuated glass bulb for a cathode-ray tube by a load of the atmospheric pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glass bulb for a cathode ray tube.

[0002]

2. Description of the Related Art As shown in FIG. 1, a glass bulb for a cathode ray tube has a panel section 1 on which an image is projected and a panel section 1.
And a neck portion 3 connected to the rear end of the funnel portion 2 and having an electron gun sealed therein, and the inside thereof is evacuated to form a vacuum vessel. used.

[0003]

However, in an exhausted glass bulb for a cathode ray tube, the interior of the glass bulb is evacuated to generate a stress due to the atmospheric pressure being applied to the outer surface of the glass bulb. I do. For this reason, a glass bulb for a cathode ray tube needs to have sufficient mechanical strength. If the mechanical strength is insufficient, the glass bulb cannot withstand the stress caused by the load of the atmospheric pressure and may be broken. Since the glass bulb for a cathode ray tube has a non-spherical shape, as for the stress distribution generated by the atmospheric pressure, as shown in FIG. 1, there is a region where a compressive stress is generated inside the glass bulb and a tensile stress is generated outside. doing. Glass structures are generally strong against compressive stress, but weak against tensile stress, and therefore
In particular, in the cathode ray tube glass bulb after exhaustion, breakage or implosion is likely to occur starting from the panel where the region where the maximum tensile stress occurs is located.

In order to solve such a problem, it is conceivable to improve the mechanical strength of the glass by increasing the thickness of the glass. However, increasing the thickness of the glass increases the weight and makes the handling inconvenient. Not only will it be expensive,
It is not preferable in terms of workability and economy.

It is an object of the present invention to provide a glass bulb for a cathode ray tube having high mechanical strength without increasing the weight of the glass bulb.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems and objects, and has a glass panel for a cathode ray tube comprising a substantially rectangular panel portion and a funnel portion and a neck portion connected to the panel portion. Wherein a compressive stress layer is formed on an outer surface and an inner surface of the panel portion, and a compressive stress value C of the compressive stress layer is generated by an atmospheric pressure load on the exhausted panel portion of the cathode ray tube glass bulb. the maximum tensile stress value T _MAX, is a glass bulb for a cathode ray tube characterized by having a C ≧ T _MAX the relationship.

In the present invention, the compressive stress value C of the compressive stress layer has a relation of 2T _MAX ≧ C ≧ T _MAX .

[0008]

In the glass bulb for a cathode ray tube of the present invention,
By forming the compressive stress layer on the outer surface and the inner surface of the panel portion, the mechanical strength of the panel portion is improved, and the glass surface forming the panel portion is hardly damaged. Moreover, the compressive stress value C of the compressive stress layer is larger than the maximum tensile stress value T _MAX generated in the panel portion by the load of the atmospheric pressure after exhausting the inside of the glass bulb for a cathode ray tube, C ≧
With _TMAX, it is possible to sufficiently withstand the tensile stress generated in the panel portion of the glass tube for a cathode ray tube after evacuation, and to prevent breakage and destruction of the glass bulb for a cathode ray tube used as a vacuum vessel.

In the present invention, the reason why the compressive stress value C of the compressive stress layer of the panel portion is 2T _MAX ≧ C ≧ T _MAX is that the compressive stress value C is larger than the maximum tensile stress value T _MAX generated in the panel portion. If it is too small, it cannot withstand the tensile stress generated in the panel part of the glass bulb for a cathode ray tube after exhaustion, and as a result, the glass bulb will be damaged or broken, and the compressive stress value C is larger than 2T _MAX. If it is large, it is difficult to form a uniform compressive stress layer on the entire panel.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a glass panel for a cathode ray tube according to the present invention will be described based on embodiments.

The drawings will be described with reference to FIG.

The glass bulb for a cathode ray tube comprises a panel portion 1, a funnel portion 2 and a neck portion 3 connected to the panel portion 1, and in this embodiment, the panel portion 1 has a short side of 471.6 mm and a long side. Use a 29-inch glass panel with an effective screen of 600.8 mm. A compressive stress layer is formed on the inner surface and the outer surface of the panel portion 1 of the glass bulb for a cathode ray tube, and a compressive stress value C of the compressive stress layer is formed.
Is 105.6 kg / cm ² . In the present embodiment, the maximum tensile stress value T _MAX generated in the panel unit 1 by the atmospheric pressure load after exhausting the inside of the glass bulb for a cathode ray tube is 8
Was 4.5 kg / cm ^2, the compressive stress layer formed in the panel portion 1, the compression stress value C is about the maximum tensile stress value T _MAX occurring panel portion 1 after the glass bulb exhaust 1.25 It is formed with twice the size. The formation of the compressive stress in the panel portion 1 is performed by molding the panel, transferring the panel to an annealing furnace in which the maximum temperature is set to 480 ° C. between the annealing point and the strain point of the panel glass, annealing the panel, and slowly cooling the panel. This is done by cooling to

Thirty such glass bulbs for a cathode ray tube are prepared, and after evacuating each of the glass bulbs for a cathode ray tube, the outer surface of a panel portion is subjected to No. 150 abrading. After the temperature was raised to 400 ° C. and maintained for 15 minutes, the temperature was lowered at 20 ° C./minute,
A down shock destruction test was performed.

As a result, in all the glass bulbs for cathode ray tubes, no breakage, destruction, etc. occurred, and good results were obtained.

[0015]

As described above, according to the glass bulb for a cathode ray tube of the present invention, the mechanical strength is improved by the compressive stress layers formed on the outer surface and the inner surface of the panel portion.
Compressive stress value C of such compressive stress layer, the maximum tensile stress value T _MAX occurring panel portion by the load of atmospheric pressure after evacuation of the internal CRT glass bulb, by a C ≧ T _MAX, after evacuation It can fully withstand the tensile stress generated in the panel part of the glass tube for cathode ray tubes,
This has an excellent effect that breakage and destruction of the glass bulb for a cathode ray tube used as a vacuum vessel can be prevented.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a glass bulb for a cathode ray tube.

[Explanation of symbols]

 1 Panel 2 Funnel 3 Neck

Claims (2)

[Claims] 1. A cathode ray tube glass bulb comprising a substantially rectangular panel portion and a funnel portion and a neck portion connected to the panel portion, wherein a compressive stress layer is formed on an outer surface and an inner surface of the panel portion. The compressive stress value C of the compressive stress layer has a relationship of C ≧ T _{MAX with} respect to a maximum tensile stress value T _MAX generated by an atmospheric pressure load on the exhausted glass panel for a cathode ray tube. Glass bulb for cathode ray tube. 2. A compression stress value C of the compression stress layer is 2T.
CRT glass bulb of claim 1, characterized in that it comprises a _MAX ≧ C ≧ T _MAX the relationship.