JP2001220162A - Method and device for cooling glass panel for cathode ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and device for cooling a glass panel for a cathode ray tube be which deformation of the glass panel can be suppressed and cooling can be efficiently executed. SOLUTION: In the method for cooling the glass panel for the cathode ray tube 10 having a face part 10a of nearly rectangular shape and a skirt part which extends from the face part 10a nearly in a vertical direction via a blend part, the glass panel for the cathode ray tube is press-molded and then when the glass panel 10 in a metallic die is cooled by blowing air from a cooling duct 14 thereabove, cooling is executed by blowing air upon a peripheral region 11 of the face part 10a at both end parts of either one axis among a short axis and a long axis of the glass panel 10 from the cooling duct 14 having two blow-out ports 13 and 13 formed in parallel across a central region.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for cooling a glass panel for a cathode ray tube, in particular, a glass panel for a cathode ray tube immediately after molding.

[0002]

2. Description of the Related Art As shown in FIG. 4, a glass panel 10 for a cathode ray tube comprises a substantially rectangular face portion 10a and a skirt portion 10c extending substantially vertically from the face portion 10a via a blend portion 10b. .

[0003] A glass panel for a cathode ray tube is generally manufactured by press-molding a high-temperature molten glass lump in the following manner.

First, high-temperature molten glass is supplied to a molding die arranged at a predetermined interval on a table which rotates intermittently in a press molding apparatus, and the die is moved to a molding position by intermittent rotation of the table. Then, the plunger is lowered to push the molten glass block in the mold, and then the plunger is raised. Thus, a substantially rectangular glass panel for a cathode ray tube is formed from the molten glass lump. Since the glass panel for a cathode ray tube after press molding is still in a high temperature state, the mold is successively moved to a plurality of cooling positions by intermittent rotation of the table to cool the glass panel in the mold. Normally, cooling at the cooling position is performed by blowing air onto the inner surface of the glass panel from a cylindrical or substantially rectangular cooling duct having a circular or substantially rectangular outlet. The glass panel is taken out of the mold after being cooled to a predetermined temperature suitable for releasing from the mold, and the mold from which the glass panel is taken out is transferred to the molten glass lump supply position again by intermittent movement of the table. You.

In recent years, with the flattening of the outer surface of the face portion of the glass panel for a cathode ray tube, the inner surface thereof has been relatively flattened as compared with the related art, but is attached to the inner surface of the glass panel. In order to maintain the shadow mask stable and maintain the mechanical strength of the cathode ray tube,
As shown in FIG. 5, on the inner surface of the glass panel 10, the increase in the glass thickness t (referred to as a wedge) from the central region to the peripheral region of the face portion 10 a is caused by the short-axis end portions of the glass panel 10 or There has been proposed a glass panel 10 having a shape that is enlarged in one of the peripheral regions at both ends of the long axis.

That is, the shadow mask is attached to the inner surface side of the glass panel via a pin sealed to the skirt portion of the glass panel, and the distance from the shadow mask to the inner surface of the glass panel is equal to any one of the shadow masks. Although it must be exactly the same at the points, since the shadow mask itself is a thin plate of only about 0.2 to 0.3 mm, if it is mounted along the flattened inner surface, sufficient shadow mask There is a problem that stable retention cannot be obtained. Therefore, the wedge is increased in the peripheral region of either the short-axis end portion or the long-axis end portion of the inner surface of the glass panel, and the shadow mask is attached by bending the mask vertically or vertically along the periphery. Thus, the shape retention of the shadow mask is supplemented. In addition, since the inside of the cathode ray tube is evacuated, a load of atmospheric pressure is generated, and the maximum tensile stress is easily generated at the short axis end of the glass panel. In some cases, the wall thickness may be larger than the end of the long axis.

Some of the glass panels for a cathode ray tube in consideration of such circumstances have, for example, a thickness difference of 10 mm or more between a peripheral region at a long axis end and a peripheral region at a short axis end.

[0008]

In the conventional cooling process for a glass panel for a cathode ray tube, the cross section of the cooling duct is circular or substantially rectangular, and the cooling duct is blown from the cooling duct to the central region of the face of the glass panel. Since the air is cooled by flowing to the peripheral area of the face, the central area of the face tends to be intensively cooled.

However, when cooling a glass panel in which one peripheral region of the face portion is thicker than the other, the central region of the face portion is intensively cooled and the heat capacity of the glass is reduced. In the peripheral region where the surface portion 10a is large, as shown by the hatched region in the plan view of FIG. 6, the high-temperature region along the thick peripheral region 11 is generated over a wider range than the other peripheral region 12, so that the face portion 10a Temperature balance deteriorates extremely, and as a result,
As shown by the dotted lines in FIGS. 6 and 7, the central region of the face portion 10 a, which is a low-temperature region, warps in the inner surface direction,
There is a problem that the glass panel is deformed.

If the amount of air blown from the cooling duct to the glass panel per unit time is reduced in order to solve such a problem, the cooling time at each cooling position must be prolonged, and the table of the press forming apparatus needs to be prolonged. The intermittent rotation cycle becomes longer, resulting in lower production efficiency.

Accordingly, an object of the present invention is to suppress deformation of a glass panel for a cathode ray tube by suppressing the deformation of the glass panel when the glass panel is press-molded and then cooled by blowing cooling air from above. It is an object of the present invention to provide a method and an apparatus for cooling a glass panel for a cathode ray tube, which can be cooled in a short time.

[0012]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems and objects, and has a substantially rectangular face portion and a skirt portion extending substantially vertically from the face portion via a blend portion. A method of cooling a glass panel for a cathode ray tube having a method of supplying molten glass to a mold, and then lowering a plunger to press-mold the glass panel for a cathode ray tube, and then with respect to the glass panel for a cathode ray tube in the mold. When cooling by blowing air from a cooling duct above the cooling duct having two outlets formed in parallel with a central area therebetween, a short axis or a long axis of the glass panel for the cathode ray tube is formed. A method for cooling a glass panel for a cathode ray tube, wherein air is blown to a peripheral region of a face portion at either end of one of the shafts to cool the surface.

Further, the present invention is an apparatus for cooling a glass panel for a cathode ray tube having a substantially rectangular face portion and a skirt portion extending from the face portion through a blend portion in a substantially vertical direction. A cooling duct having two outlets formed in parallel with a central area therebetween along the peripheral area of the face part at either end of either the short axis or the long axis of the glass panel for a cathode ray tube in A cooling device for a glass panel for a cathode ray tube, comprising:

[0014]

According to the cooling method and the cooling device of the present invention, a cooling duct having two outlets formed in parallel with a central area therebetween is used to separate one of the face portions of the face portion of the glass panel for a cathode ray tube from facing one another. By cooling the area by blowing air, the central area of the face of the glass panel can be prevented from being intensively cooled, and the central area of the face is not overcooled. In the CRT glass panel where the peripheral area of the part has a larger thickness than the other part, it is possible to intensively cool one peripheral area that is a thick part, thereby suppressing the deterioration of the temperature balance of the face part However, the glass panel is not deformed in the cooling step.

Also, since it is not necessary to reduce the amount of air blown from the cooling duct to the glass panel per unit time, good cooling can be performed without lowering production efficiency.

In particular, the present invention is suitable for cooling a glass panel for a cathode-ray tube in which the outer surface of the face portion is substantially flat and the peripheral regions at both ends of one shaft have a larger thickness than the other. It is suitable for cooling a glass panel for a cathode ray tube having a substantially cylindrical inner surface such that the thickness of the peripheral region at both ends of one shaft is 1.5 times or more the thickness of the other peripheral region. It is. When the thickness difference between the one peripheral region and the other peripheral region is small, the entire inner surface exhibits a surface approximating a spherical shape, and the deterioration of the temperature balance due to the thickness difference in the peripheral region is small. Since it tends to be suppressed, the conventional deformation hardly occurs. Here, that the outer surface of the face portion is substantially flat means that the radius of curvature of the outer surface in the diagonal axis direction is 30,000 mm.
As described above, the thickness in the peripheral region of the face portion refers to the thickness at the end of the effective screen.

Further, as described above, according to the present invention, the dies arranged at predetermined intervals on the intermittently rotating table are sequentially moved to a plurality of cooling positions by the intermittent rotation of the table, so that the dies inside the die can be moved. This is suitable for cooling a glass panel, and the present invention may be applied to at least one of a plurality of cooling positions.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments.

In this embodiment, a case will be described in which a glass panel for a cathode ray tube having a size of 32 inches is press-molded and then sequentially moved to three cooling positions to cool the glass panel in a mold.

In the figure, the same parts as those described above are denoted by the same reference numerals, and description thereof will be omitted.

FIGS. 1 and 2 show the basic structure of the present invention. FIG. 1 is a sectional view of a glass panel in a mold in a short axis direction, and FIG. 2 is a long axis of FIG. AA in the direction
FIG. 3 is a cross-sectional view, and FIG. 3 is an explanatory diagram showing an arrangement relationship between the face portion of the glass panel and the cooling duct.

The outer surface of the face portion 10a of the glass panel 10 has a radius of curvature of 100,000 m in the diagonal axis direction.
m, and the thickness t at the center of the face portion 10a is 13.8 m.
m, the thickness ts at both ends of the short axis which is the thick peripheral region 11 is 22.6 mm, and the thickness tl of the peripheral region at both ends of the long axis which is one peripheral region 12 is 13.4 mm.

A cooling duct 14 having two outlets 13, 13 formed parallel to each other with a central area therebetween along the peripheral area of the short axis end of the glass panel 10 is connected to the cooling duct 14 after the press position. Of the three cooling positions, it is attached to the third cooling position, and the first and second cooling positions are provided with a conventional rectangular (400 mm × 680 m).
m) cooling duct (not shown) is used.

The outlets 13 are provided in the glass panel 1.
The opening size is 70 mm in the short axis direction and 450 mm in the long axis direction.

In order to compare the cooling method of the present invention with the conventional cooling method, as the conventional cooling method, the conventional substantially rectangular and cylindrical cooling ducts of φ200 mm were attached to three cooling positions after the press position. The glass panel having the same size and the same shape as the glass panel 10 described above was cooled. Table 1 shows the cooling conditions and the results.

[0026]

[Table 1]

As can be seen from Table 1, in the conventional cooling method, in order to suppress the deformation of the glass panel due to cooling and to cool the temperature of the glass panel to a predetermined temperature suitable for mold release, the first to the first cooling methods are used. In order to reduce the air pressure from the third duct to a low pressure, and particularly to suppress the deterioration of the temperature balance with the thick surrounding area in the face portion, the air pressure in the third duct is set to be lower than the air pressure in the first and second ducts. 80%
Had to be reduced. As a result, the production efficiency was reduced by prolonging the cycle time, and the non-defective rate was only 52%.

On the other hand, according to the present invention, the yield rate was improved by 22% as compared with the prior art, and the deformation of the glass panel due to cooling was improved. In addition, since the central region of the face portion is not overcooled and one peripheral region which is a thick portion can be intensively cooled, the air pressure at each cooling position can be made higher than before, and as a result, The cycle time was reduced by about 10% compared to the conventional case.

In the cooling method of the present invention, the reason why the air pressure in the third duct is lower than the air pressure in the first and second ducts is that the glass panel at the first and second cooling positions Although the central region of the face portion is cooled intensively, the air blown from the cooling duct to the central region of the face portion of the glass panel flows to the peripheral region of the face portion, so that the glass transferred to the third cooling position. This is because, in the case of the panel, the temperature in the peripheral area of the face part is somewhat lowered.

[0030]

As described above, according to the present invention,
For the glass panel in the mold after press-molding the glass panel for the cathode ray tube, suppress the deformation of the glass panel,
In addition, there is an excellent effect that cooling can be performed efficiently.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a glass panel in a mold in a short axis direction.

FIG. 2 is a sectional view taken along the line AA in the long axis direction of FIG.

FIG. 3 is an explanatory diagram showing an arrangement relationship between a face portion of a glass panel and a cooling duct.

FIG. 4 is an explanatory view of a glass panel for a cathode ray tube.

FIG. 5 is an explanatory view of a wedge of a glass panel for a cathode ray tube.

FIG. 6 is an explanatory diagram showing temperature balance and deformation of a face portion.

FIG. 7 is a sectional view taken along the line BB of FIG. 6;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Glass panel for cathode ray tubes 11, 12 Peripheral area 13 Outlet 14 Cooling duct

Claims (2)

[Claims] 1. A method for cooling a glass panel for a cathode ray tube having a substantially rectangular face portion and a skirt portion extending substantially vertically from the face portion via a blend portion, wherein molten glass is supplied to a mold. Then, after lowering the plunger to press-mold the glass panel for a cathode ray tube, the central area is cooled by blowing air from a cooling duct above the glass panel for a cathode ray tube in a mold. Cooling is performed by blowing air from a cooling duct having two outlets formed in parallel to each other to the peripheral region of the face portion at both ends of either the short axis or the long axis of the glass panel for a cathode ray tube. A method for cooling a glass panel for a cathode ray tube, characterized in that: 2. An apparatus for cooling a glass panel for a cathode ray tube having a substantially rectangular face portion and a skirt portion extending in a substantially vertical direction from the face portion via a blend portion, the cathode ray tube being provided in a mold. A cooling duct having two outlets formed in parallel with a central region therebetween along a peripheral region of a face portion at either end of either the short axis or the long axis of the glass panel. A cooling device for a glass panel for a cathode ray tube, characterized in that: