JP2000133171A - Glass bulb for cathode-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a glass bulb for a cathode-ray tube, the glass bulb having high mechanical and structural strength without increasing in weight. SOLUTION: In a glass bulb 1 for a cathode-ray tube, comprising a panel part 2 having a face part 2a and a skirt part 2b extending almost vertically from the peripheral edge of the face part 2a, a funnel part 3 joined to the panel part 2, and a neck part 4, with an anti-explosion band 5 fastened to the outer surface of the skirt part 2b which serves as the maximum outer peripheral part of the panel part 2, compressive stress layers are formed at least on the outer and inner surfaces of the panel part 2. For a maximum tensile stress value Tmax produced by the load of atmospheric pressure on the cathode- ray tube glass bulb 1 evacuated inside, the compressive stress value C of the compressive stress layer and a compressive stress value Cb achieved by fastening of the anti-explosion band 5 have a relation of |C+Cb|>=Tmax.

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 FIGS. 1 and 2, a glass bulb 1 for a cathode ray tube has a panel section 2 on which an image is projected.
And a funnel-shaped funnel 3 connected to the panel 2
And a tubular neck portion 4 in which an electron gun is mounted inside, which is welded to the small opening end of the funnel portion 3. The panel portion 2 has a face portion 2a serving as a visual image area and a skirt portion 2b extending substantially perpendicularly from the periphery of the face portion 2a, and an end face of the skirt portion 2b (hereinafter referred to as a seal edge). And the end face of the wide opening end of the funnel portion 3 is sealed via a sealing glass for sealing.

The glass bulb 1 for a cathode ray tube is used as a vacuum container by exhausting the inside of the glass bulb 1 after mounting an electron gun on the neck portion 4.
A vacuum stress is generated on the outer surface of the glass bulb 1 due to a load of atmospheric pressure. Therefore, the glass bulb 1 needs sufficient mechanical and structural strength. That is, if these strengths are insufficient, the glass bulb 1 cannot withstand the vacuum stress caused by the load of the atmospheric pressure, causing not only fatigue destruction but also fine scratches on the glass surface or impact on the glass surface. Addition of a physical factor such as being performed also results in destruction. Further, since the temperature of the glass bulb 1 is raised to about 400 ° C. in the manufacturing process of the cathode ray tube, the thermal stress generated by the temperature rise and the vacuum stress generated by the above-described exhaust may be combined to cause breakage. is there.
In particular, in the case of the glass bulb 1 for a cathode ray tube, since the inside thereof is in a vacuum, a sudden inflow and outflow of air occurs inside and outside the glass bulb at the same time as the destruction, so that the "broken-out" in which the broken glass pieces are scattered. It is dangerous.

[0004] Incidentally, the stress generated in the glass bulb for a cathode ray tube due to the vacuum stress after evacuation includes a compressive stress acting toward the inside of the glass bulb 1 and a compressive stress toward the outside because the glass bulb 1 has a non-spherical shape. In this case, the regions where the tensile stress is generated coexist with the distribution shown in FIG.
Therefore, the glass bulb 1 for an evacuated cathode ray tube has a high strength against compressive stress, but has a low strength against tensile stress. Breaking and implosion are likely to occur starting from a region where the generated tensile stress is maximum, that is, a region from the periphery of the face portion 2a of the panel portion 2 to the skirt portion 2b.

For this reason, in the conventional glass bulb 1 for a cathode ray tube, the thickness of the glass is increased, and the tensile stress generated in the glass bulb due to the vacuum stress after evacuation is suppressed. As described above, the metal explosion-proof band 5 is fastened to the outer surface of the skirt portion 2b of the panel portion 2, which is the maximum outer peripheral portion of the glass bulb 1, and a compressive stress is given by the explosion-proof band 5 so that the panel portion The strength of the glass bulb 1 is maintained by relaxing the tensile stress generated from the periphery of the face 2a to the skirt 2b.

[0006]

However, increasing the thickness of the glass increases the weight of the glass bulb, which not only makes it inconvenient to handle, but also increases the cost and increases workability and economy. Is not preferred. In particular,
As the size of the cathode ray tube increases, the problem of weight increase due to the thickening of the glass of the glass bulb becomes more serious.

Further, in a glass bulb in which the face portion of the panel portion is flattened for the purpose of improving visibility, the tensile stress generated in the glass bulb due to vacuum stress after evacuation increases in proportion to the flattening of the face portion. Because they tend to
From the viewpoint of flattening the face portion, it is desired to provide the glass bulb with strength that does not cause breakage or implosion without increasing the weight of the glass bulb.

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

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems and objects, and has a panel having a substantially rectangular face portion and a skirt portion extending substantially perpendicularly from the periphery of the face portion. And a funnel portion and a neck portion connected to the panel portion, and a glass bulb for a cathode ray tube having an explosion-proof band fastened to an outer surface of a skirt portion which is a maximum outer peripheral portion of the panel portion. it is formed compressive stress layer on the outer and inner surfaces of the parts, the compression stress value C _b by the compression stress value C and the fastening of the explosion-proof band of the compression stress layer is, for a cathode ray tube having an evacuated internal For the maximum tensile stress value _Tmax generated by the atmospheric pressure load on the glass bulb, | C + _Cb | ≧ T
_A glass bulb for a cathode ray tube, characterized by having a relation of _max .

[0010] In the present invention, the compression stress value C _b by fastening of the compression stress value of the compressive stress layer C and the explosion-proof band, 4T _max ≧ | to have ≧ T _max the relationship | C + C _b It is characterized by.

In the present invention, the maximum tensile stress T
_max indicates the maximum tensile stress value generated in the glass bulb when the glass bulb is evacuated in a state where no explosion-proof band or the like is applied to the glass bulb for a cathode ray tube.

[0012]

In the glass bulb for a cathode ray tube of the present invention,
Since the compressive stress layer is formed on at least the outer surface and the inner surface of the panel portion, the mechanical and structural strength of the panel portion is increased, and the glass surface is less likely to be scratched. Considering that the tensile stress generated from the periphery of the face portion of the panel portion to the skirt portion is alleviated by the explosion-proof band fastened to the outer surface of the skirt portion as the maximum outer peripheral portion, the compression stress layer compressive stress value C and the compression stress value C _b by fastening of the explosion-proof band, the maximum tensile stress value T _max caused by the load of atmospheric pressure in a glass bulb for a cathode ray tube which is evacuated internally, | C + C _b | By having a relationship of ≧ T _max, it is possible to sufficiently withstand the tensile stress generated in the glass bulb for a cathode ray tube after evacuation, and the glass for a cathode ray tube used as a vacuum vessel is used. Subaru can be prevented from destruction and implosion.

In the present invention, 4T _max ≧ | C
It is more preferable to have a relationship of + C _b | ≧ T _max .

[0014] The absolute value of the sum of the compressive stress value C _b by the compression stress value C and the explosion-proof band of compressive stress formed in the panel layers and smaller than the maximum tensile stress value T _max of the glass bulb, after evacuation It cannot withstand the tensile stress generated in the glass bulb for a cathode ray tube, resulting in breakage and implosion of the glass bulb.

Further, the absolute value of the sum of the compressive stress value C _b by the compression stress value C and the explosion-proof band of the compressive stress layer formed in the panel portion and larger than 4T _max, due to the increase of the glass inside the tensile stress Implosion easily occurs. That is, when a compressive stress layer is formed on the inner and outer surfaces of the glass, at the same time, a tensile stress layer is formed at the center of the inside of the glass at a value of の of the compressive stress. Once the entered scratch reaches the internal tensile stress layer, it rapidly becomes implosive due to rapid crack development. on the other hand,
The compressive stress value of the explosion-proof band fastened to the outer surface of the skirt, which is the maximum outer periphery of the panel, varies slightly depending on the thickness and shape of the panel and funnel, which constitute the glass bulb, and their measurement positions. although some average was 78.2kg / cm ^2, the change in the absolute value of the sum of the compressive stress value C _b by the compression stress value C and the explosion-proof band of the compressive stress layer formed in the panel portion of the compressive stress layer This is largely due to the change in the compressive stress value C. Therefore, from the viewpoint of preventing implosion caused by tensile stress inside glass, | C +
C _b | is more preferably 4T _max or less.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The glass bulb for a cathode ray tube according to the present invention will be described below based on embodiments.

The glass bulb for a cathode ray tube is shown in FIG.
As shown in FIG. 2, an explosion-proof band 5 is formed on the outer surface of a skirt portion 2b which is composed of a panel portion 2, a funnel portion 3 and a neck portion 4 connected to the panel portion 2, and which is the maximum outer peripheral portion of the panel portion 2. Is fastened. The formation of the compressive stress in the panel section 2 is performed by feeding a molten glass lump to a mold and pressing the glass panel to form the glass panel, and then setting the maximum temperature to 480 ° C. between the annealing point and the strain point of the glass panel. The glass panel is conveyed and passed through a slow cooling furnace set at a temperature of 40 ° C., gradually cooled, and then cooled to room temperature.

(Embodiment 1) In this embodiment, a 25-inch panel having an aspect ratio of 4: 3 is used for a panel portion.
A compressive stress layer is formed on the inner surface and the outer surface of the panel portion, and the compressive stress value C of the compressive stress layer is 101.2.
kg / cm ² . The compressive stress value C _b by explosion-proof band is 101.3kg / cm ² at the corner portions of the diagonal axis end of the panel portion. On the other hand, in the present example, the maximum tensile stress value T _max generated in the glass bulb for a cathode ray tube whose inside was evacuated was 78.8 kg / cm ² ,
The absolute value of the sum of the compressive stress value C _b by the compression stress value C and the explosion-proof band of compressive stress layer formed in the panel portion is approximately 2.6 times the maximum tensile stress value T _max occurring in the glass bulb after evacuation It is.

(Embodiment 2) In this embodiment, a 28-inch panel having an aspect ratio of 16: 9 is used for the panel portion, and a compressive stress layer is formed on the inner surface and the outer surface of the panel portion. The compressive stress value C of the compressive stress layer is 14
2.1 kg / cm ² . The compressive stress value C _b by explosion-proof band is 75.7kg / cm ² at the corner portions of the diagonal axis end of the panel portion. On the other hand, in the present embodiment, the maximum tensile stress value _Tmax generated in the glass bulb for a cathode ray tube whose inside is evacuated is 86.8 kg / cm ² , and the compressive stress value C of the compressive stress layer formed on the panel portion is equal to the maximum tensile stress value _Tmax. the absolute value of the sum of the compressive stress value C _b by explosion band, the maximum tensile stress value T generated in the glass bulb after evacuation
It is about 2.5 times _max .

Thirty glass bulbs for cathode ray tubes of Examples 1 and 2 were prepared, and 150 bulbs were placed on the outer surface of the panel.
Then, the glass bulb for a cathode ray tube was heated at a rate of 5 ° C./min to 400 ° C. and maintained for 15 minutes.
After the temperature was lowered at 0 ° C./min, a down shock destruction test was performed. As a result, in all of the glass bulbs for cathode ray tubes of Examples 1 and 2, no destruction occurred at all, and good results were obtained.

In order to evaluate the explosion-proof characteristics of the glass bulbs of Examples 1 and 2, an explosion-proof test using the ball impact method was performed on each of ten glass bulbs. No implosion of the valve was observed.

[0022]

As described above, according to the glass bulb for a cathode ray tube of the present invention, a high mechanical strength capable of sufficiently withstanding the tensile stress generated in the glass bulb after exhausting without increasing the weight of the glass bulb. Further, it has an excellent effect that it has structural strength and can prevent breakage and implosion of a glass bulb for a cathode ray tube used as a vacuum vessel.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a distribution of stress generated in a glass bulb for a cathode ray tube.

FIG. 2 is an explanatory view of a glass bulb for a cathode ray tube.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Glass bulb for cathode ray tubes 2 Panel part 2a Face part 2b Skirt part 3 Funnel part 4 Neck part 5 Explosion-proof band

Claims (2)

[Claims] 1. A substantially rectangular face portion and a periphery of the face portion.
Panel having a skirt extending substantially perpendicularly from the edge
And a funnel portion and a neck portion connected to the panel portion.
Of the skirt, which is the maximum outer periphery of the panel
Glass for cathode ray tubes with explosion-proof band fastened to the outer surface
In the valve, at least the outer surface and the panel
And a compressive stress layer formed on the inner surface.
The compression stress value C of the force layer and the fastening of the explosion-proof band
Compressive stress value C_b But the inside of the cathode ray tube exhaust
Maximum tensile stress T caused by atmospheric pressure load on the valve
_max | C + C_b | ≧ T_max Have a relationship
A glass bulb for a cathode ray tube characterized by the above-mentioned. 2. A compression stress value C _b by fastening of the compression stress value of the compressive stress layer C and the explosion-proof band, 4T
_max ≧ | C + C _b | a cathode ray tube glass bulb according to claim 1, wherein a ≧ T _max following relationship.