JP3407581B2 - Cathode ray tube - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cathode ray tube using a face panel glass, and more particularly to a cathode ray tube capable of locally controlling the destruction range of the face panel when the cathode ray tube is imploded.

[0002]

2. Description of the Related Art Recently, a CR having a cathode ray tube (hereinafter referred to as a CRT), which has a large screen and a high image quality
T is flattening the face panel glass from the viewpoint of improving visibility. In order to obtain a face panel glass with a flat feeling, the face curved surface of a large screen is made an aspherical surface indicated by a hyperbola or a power-law polynomial, or the radius of curvature is increased, for example, the radius of curvature is 8000 mmR to 1000 mm.
The face panel glass is made substantially flat by increasing the size to about 00 mmR.

Generally, in the manufacturing process of a CRT, R (red), G (green), B (blue) phosphor stripes and carbon stripes are formed on the inner surface of a face panel glass, and a color selection is made by an assembled aperture grill. After the electrodes are set, the funnel portion coated with the neck carbon and the interior carbon and the panel portion are bonded and fixed with frit glass, and the electron gun is sealed in the neck portion of the funnel portion.
^{-5 to} 10 ^-7 Torr vacuum evacuation
A vacuum is applied to the inside of the glass tube composed of the funnel portion and the panel portion.

After that, the getter is high-frequency heated from the outside of the funnel portion to evaporate barium or the like to make the inside of the glass tube a high vacuum, and the skirt portion of the panel portion is covered with an explosion-proof band or the like to prevent implosion of the glass. The glass tube is fitted in such a manner as to be surrounded by shrink fitting, and a reinforcing process is performed to apply external pressure to the glass tube.

After that, carbon is coated on the outer surface of the funnel, and after performing knocking, aging, etc., it is inspected whether the fluorescent surface of the CRT or the electron gun operates normally,
The CRT is completed.

When a flat face panel glass, which is formed by molding the face panel 3 of the panel portion 2 of the flat tube body 1 into a flat shape, is used in the vacuum evacuation step in the above-described manufacturing process, as shown in FIG. Atmospheric compressive stress 6a acts on the funnel 4, tensile stress 6b acts on the side wall of the panel portion 2, and the face panel 3 is sucked toward the neck 5 side as shown by the alternate long and short dash line, like the face panel 3 '. The curved surface will have a concave R.

For example, a flat tube body 1 having a 28-inch tube and a face panel 3 having a thickness of 15.5 mm is 10 ^{-5 to} 10
The deformation amount δ when exhausted at ⁻⁷ Torr becomes approximately 400 μm at the center position of the face panel 3 and has a concave curvature.

The compressive stress 6a due to the atmosphere applied to the flat tube body 1 is applied to the tensile stress 6a by the band 7 for shrink fitting.
By applying an external force F in the direction opposite to b, the tensile stress (glass is weak to tensile stress) in the side wall of the panel portion 2 is canceled and the compressive stress 6 is applied from the inside of the face panel 3.
Face panel 3'with a pressing stress 6c facing a
The original flat face panel 3 position is returned from the position.

However, the recovery rate of the deformation amount δ to the original is as low as about 20% by such compensation processing by the implosion prevention band 7, and the center of the face panel 3 is displaced in the 28-inch flat tubular body described above. Since the amount δ = 320 μm is also present and a CRT having a flat face panel cannot be obtained, the face panel glass of the panel portion 2 is not flattened at the time of pressing, and the curved surface of the face panel is, for example, a vacuum deformation amount when evacuated. In consideration of this, the curvature of the face panel 2 is selected in advance as a convex curvature, or the flat tube 1 is obtained with a curvature that allows for the amount of deformation due to the compression force of the band.

[0010]

According to the method described in the above-mentioned conventional configuration, for example, assuming that the face panel 3 is completely flat, a vertical external force V _F orthogonal to the face panel 3 is obtained. Is applied as shown in FIG. 5, the reaction force H _F parallel to the surface of this face panel does not work like a face panel having a curvature, so that the external force V
_{By F} , the face panel 3 is depressed as it is toward the inside of the flat tube body 1 (direction of the neck 5), and so-called implosion occurs.

That is, as the radius of curvature R of the face panel 3 of the panel portion 2 becomes larger and approaches a flat surface, it becomes more difficult to improve the impact resistance.

Therefore, it is necessary to take measures to increase the thickness of the glass of the face panel 3 of the panel portion 2 or to attach a safety panel to the front surface of the face panel 3, resulting in an increase in the weight of the flat tube body 1 and a cost reduction. Problems such as rising prices occurred.

The present invention is intended to provide a CRT which solves the above problems, and an object of the present invention is to prevent a large implosion of the CRT even if a crack is formed by an external impact and to prevent a flat face panel. It is intended to obtain a CRT that can be made into a material and does not cause an increase in weight.

[0014]

The CRT of the present invention is a CRT made of face panel glass, in which a fragile portion is provided on the front surface of the face panel glass, and the stress distribution when the inside of the CRT is evacuated is locally reduced. It is designed to be controlled dynamically.

The CRT according to the present invention is formed by filling a groove, which is a fragile portion formed on the front surface of the face panel glass, with a resin having the same refractive index as that of the face panel and making it optically uniform.

According to the CRT of the present invention, even if an external impact is applied to the face panel and a crack is generated, the face panel of the CRT can be flattened without causing implosion and increasing the weight. You can get something.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The CRT of the present invention will be described in detail below with reference to FIGS. Note that the same parts as those of the CRT 1 described with reference to FIG. 1A and 1B are explanatory views showing an embodiment of the configuration of the CRT of this example,
2A to 2E are explanatory views of the manufacturing process of the CRT.

FIG. 1B is a side view in which the face panel 3 portion of the CRT 1A is cut away, and FIG. 1A is a front view of the face panel 3 as seen from the front. The flat tube body 1 of the CRT 1A is shown.
Is composed of a panel portion 2 and a funnel portion 4 including a neck 5.

A curved surface R having an extremely large radius of curvature is formed along the long side direction of the face panel 3, and the face panel 3 is substantially flat.

In such a panel portion 2, R, G and B
A phosphor 9 composed of a primary color stripe and a carbon stripe is formed, and a color selection electrode 10 such as an aperture grill is arranged as shown in FIG. 1B.

The neck 5 and the funnel-shaped funnel portion 4 are joined to the panel portion 2 by the frit paste at the sealing surface 22. Of course, a sub-assembled electron gun is arranged in the neck 5 via the stem 12.

Further, the adhesive tape 11 and the tightening band 7 are compressed so as to surround the skirt portion of the panel portion 2. The band 7 is crimped by a mechanical tightening method, shrink fitting, or the like. The fittings 13 for the CRT 1A are arranged at the four corners of the band 7.

When obtaining the CRT 1A as described above, when the glass of the face panel 3 of the panel portion 2 is pressed, for example, an arc-shaped groove 14 is formed on the front surface of the face panel 3 (the surface on which the television image is viewed). For example, the entire surface of 3
It is formed simultaneously so as to be divided into three parts.

The depth of the groove 14 is selected to be, for example, about 1 mm. When the CRT 1A is formed by the panel portion 2 using the flat face panel glass as described above, the flat tube body 1 is evacuated so that the flat tube body 1 is evacuated. , Stress concentrates and cracks run more easily than the surroundings.

When an impact is applied from the outside to the internal impact point 16 surrounded by the groove 14 of the face panel 3 of the CRT 1A having the above-mentioned structure, this impact force is transmitted to the groove 14. Since the stress in the groove 14 is weaker than that in other portions of the face panel 3 due to stress concentration, a crack 15 is generated in the groove 14 and the area surrounded by the arc-shaped groove 14 is intensively destroyed. It Therefore, this area is depressed in the flat tube body 1, but the left and right ends of the face panel 3 outside the groove 14 and the space between the grooves are not destroyed, and as a result, even with a large screen CRT 1A, a large implosion occurs. As a result, it is possible to minimize the scattering of glass fragments over the entire surface in front of the face panel of the CRT.

Even when an external impact is applied to the external impact point 17 between the left and right ends of the short side of the face panel 3 and the groove 14, the crack 15 from the periphery stops at the groove 14 on the right side, Only about 1/3 of the area of panel 3 is depressed, and there is no big implosion.

Of course, the above-mentioned groove 14 must be formed so as to withstand various thermal stresses applied in the CRT manufacturing process and long-term compression or tensile stress. Therefore, it is not possible to make the depth of the groove 14 too deep, but in general, the compressive stress is present in the vicinity of the outer center of the front surface of the face panel 3 as described above, and cracks are generated from the groove 14 by static pressure. It never happens.

As described above, the groove 1 is formed on the front surface of the face panel 3.
Forming 4 causes optical non-uniformity when viewing a television image, resulting in poor image quality. Therefore, this groove 1
A resin having a refractive index equal to that of the glass of the face panel 3 is embedded in the surface 4 to eliminate the optical nonuniformity.

2A to 2E show the process of FIG. 1A.
A-A 'sectional drawing of is shown. As shown in FIG. 2A, in the groove 14 formed on the front surface of the face panel 3, for example, ultraviolet rays (UV) based on acrylic monomers and oligomers are used.
The cured resin 18 is embedded (see FIG. 2B).

Although the refractive index of the glass used for the face panel 3 is n = 1.42, the above-mentioned VU curing resin 18 is used.
Can have the same refractive index, so that the optical nonuniformity can be eliminated by making the refractive index in the groove 14 the same as shown in FIG. 2B.

Since the above-mentioned UV curable resin shrinks to some extent during curing, it is necessary to devise a flatness equal to that of the panel glass surface after being embedded in the groove 14.

FIG. 2C shows the first method, in which the UV curable resin is excessively embedded in the groove 14 and a surface smoothing treatment 19 for removing the UV curable resin flat surface after curing is performed.

Further, as shown in FIG. 2B, a resin film (PET or the like) having a lower surface coated with an adhesive UV curing resin 21 similar to the UV curing resin injected into the groove 14 as shown in FIG. 2D is used as a face panel. If it is adhered to the entire surface of 3, the UV curable resin for adhesion 21 and the UV curable resin 18 in the groove 14 become compatible with each other, and at the time of curing, some irregularities can be made inconspicuous as shown in FIG. 3E.

In the above-mentioned structure, the case where the arcuate groove 14 is formed on the front side of the front surface of the face panel 3 has been described. However, as shown in FIGS. 3A to 3C, the front and rear skirt portions of the panel portion 2 or The groove 14 may be formed on the back side when the glass is pressed.

3A is a perspective view of the panel portion 2 viewed from the back side, FIG. 3B is a sectional view taken along the line BB 'in FIG. 3A, and FIG. 3C is a sectional view taken along the line CC' in FIG. 3A. As shown in FIGS. 3A and 3C, the left and right skirt portions (short side) 25L and 25R of the panel portion 2 are provided on the back side (inside) of the left and right skirt portions so as to be orthogonal to the longitudinal direction of the left and right skirt portions 25L, 25R. The left and right grooves 14L and 14R are formed so as to divide into n (4 in FIG. 3A).

Similarly, as shown in FIGS. 3A and 3B, the front and rear skirt portions (long side portions) 25D and 25U of the panel portion 2 are arranged on the front side (outer side) of the front and rear skirt portions 25D and 25U so as to be orthogonal to the longitudinal direction. The front and rear skirts are divided into n equal parts (Fig. 3A
Even if the front and rear grooves 14D and 14U are formed so as to be divided into four equal parts, it is possible to complete the depression in a predetermined small area of the face panel 3.

FIG. 4 shows still another configuration of the CRT of the present invention. Although grooves are formed in the face panel 3 and the skirt portion in each of the above-described configurations, the same as in FIG. 1 is formed by forming the fragile portion 14A by changing the material selection and the processing temperature when the panel portion 2 is pressed. In addition, the depression 3A or 3B of the face panel 3 can be selected according to the external stress applied to the impact point 16 or 17. Although the embodiment of the present invention has been described by taking the flat face panel as an example, it can be applied to a conventional CRT having a small radius of curvature of the panel.

[0038]

According to the CRT of the present invention, stress concentration is caused on the surface or the side surface of the face panel.
Even if an external shock is applied to the face panel of the RT, it is possible to avoid the implosion over the entire face panel, so that the scattering of the panel glass to the outside can be avoided. Further, since the resin having the same refractive index as the glass of the face panel improves the optical non-uniformity, deterioration of image quality is avoided, and C
This has the effect of preventing the RT weight from increasing and making the face panel flat.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a cathode ray tube of the present invention.

FIG. 2 is an explanatory view of the manufacturing process of the cathode ray tube of the present invention.

FIG. 3 is another configuration diagram of the cathode ray tube of the present invention.

FIG. 4 is still another configuration diagram of the cathode ray tube of the present invention.

FIG. 5 is an explanatory diagram of a conventional variation amount compensation of a glass tube.

[Explanation of symbols]

1 flat tube, 1A, CRT, 2 panel, 3
Face panel, 7 bands, 14, 14L, 14R, 1
4D, 14U groove

Claims (4)

(57) [Claims] 1. A cathode ray tube having a face panel , wherein a fragile portion is formed on the front surface of the face panel glass.
A cathode ray tube, wherein the cathode ray tube is provided to locally control a stress distribution when the inside of the cathode ray tube is evacuated. 2. The cathode ray tube according to claim 1, wherein the fragile portion is a groove portion. 3. The face panel glass in the groove
The cathode ray tube according to claim 1 or 2, wherein a resin having the same refractive index is embedded to make it optically uniform . 4. A cathode ray tube having a face panel , wherein grooves are formed on the front surface of the face panel glass.
And a face panel g
A resin with the same refractive index as lath is embedded to make it optically uniform.
The cathode ray tube is characterized in that a groove is provided on the front surface or the back surface of the side surface so that the stress distribution when the inside of the cathode ray tube is evacuated is locally controlled.