JPH11307018A - Cathode ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cathode ray tube lowering the difference of transmittance between the center and the periphery of the image, without using a colored glass plate even when a face part of a glass panel has a great difference of thickness between the center and the periphery. SOLUTION: A face part of a glass panel 11 of this cathode ray tube has thickness in the diagonal direction of 10 mm in the center, and that of 20 mm in the periphery. The portion near the center of the face part is inwardly stretched to depress the outside surface of it from the periphery to the center. A colored resin plate 15 is bonded to the outside surface of the face part of the glass panel 11. The colored resin plate 15 is made of an acrylic resin, and the bonding surface of it has a convex surface for fitting with the outside surface of the face part, and an approximately flat exterior surface.

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 used for a television receiver or the like.

[0002]

2. Description of the Related Art FIG. 2 is a partially broken schematic explanatory view showing the structure of a general cathode ray tube. This cathode ray tube is provided with a glass bulb composed of a glass panel 11 having a fluorescent film 10 on its inner surface, a funnel-shaped funnel 12 forming the back of the glass panel 11 and a neck 13 for accommodating an electron gun as an envelope. I have. A shadow mask 14 is provided so as to face the fluorescent film 10, and an electron beam emitted from the electron gun passes through the shadow mask 14
Is projected on the rectangular face portion, which is the front portion of the glass panel 11.

[0003] The inside of such a cathode ray tube is in a high vacuum state, compressive stress and tensile stress are generated in the glass bulb, and there is a danger of implosion when a mechanical shock is applied to the glass bulb. Therefore, the thickness of the face portion of the panel glass is thicker near the periphery than near the center in order to maintain sufficient strength as a cathode ray tube.

[0004] For this reason, in a normal glass panel, a difference tends to occur in the transmittance between the periphery and the center of the face portion, and the luminance at the periphery is lower than that at the center.

[0005] The transmittance of the glass panel varies depending on the application, but as the transmittance of the glass panel decreases, the transmittance difference due to the difference in thickness between the center and the periphery of the face portion increases.

[0006] Against this background, a glass panel made of glass having high transmittance is used, and a colored glass plate is attached to the face of the glass panel with an adhesive to reduce the difference in transmittance between the center and the periphery. In addition, a cathode ray tube with a reduced luminance difference has been proposed.

[0007]

In recent years, flattening of glass panels has been demanded, and attempts have been made to increase the radius of curvature of the outer surface of the face portion in the diagonal axis direction to 10,000 mm or more. When the radius of curvature of the face portion of the glass panel increases, the risk of implosion increases. Therefore, as described above, the radius of curvature of the outer surface of the face portion of the glass panel in the diagonal axis direction is set to 1000.
When the thickness is set to 0 mm or more, the peripheral thickness (TE) and the central thickness (T ₀ ) in the diagonal direction of the face portion are determined by:
It is designed to satisfy the equation: 1.2 ≦ TE / T ₀ ≦ 4.0.

However, if the difference in thickness between the periphery and the center of the face portion of the glass panel becomes large, even if the above-described colored glass plate is pasted on the front surface, the difference in the transmittance between the periphery and the center is increased. Is difficult to make sufficiently small.

Further, the cathode ray tube becomes heavier as the thickness of the face portion of the glass panel becomes larger. However, if a colored glass plate is pasted on the front surface of the cathode ray tube, the weight of the cathode ray tube further increases, making transport difficult. There is also.

Further, the radius of curvature of the outer surface of the face portion in the diagonal axis direction is extremely increased (for example, 100,000).
When a glass bulb is manufactured using such a glass panel and the inside is kept in a vacuum, the vicinity of the center of the face part is pulled inward, and the outer surface becomes concave from the periphery toward the center. And the image becomes difficult to see.

The present invention has been made in view of the above circumstances, and a main object of the present invention is to use a colored glass plate without using a colored glass plate even if the thickness difference between the center and the periphery of the face portion of the glass panel is large. An object of the present invention is to provide a cathode ray tube capable of reducing a difference in transmittance between the center and the periphery of an image.

[0012]

SUMMARY OF THE INVENTION A cathode ray tube according to the present invention comprises a glass panel having a fluorescent film on the inner surface, a glass bulb comprising a funnel forming the back of the glass panel, and a neck for accommodating an electron gun. The inside is kept in a vacuum, and the face portion of the glass panel has an outer surface in which the thickness at the center is smaller than the thickness at the periphery and is concave from the periphery toward the center, and the face portion A colored resin plate is adhered to the outer surface of the glass panel, and the colored resin plate has a convex adhesive surface that fits on the outer surface of the face portion and a substantially flat outer surface. Characterized in that the difference in transmittance due to the difference in thickness between the center and the periphery of the face portion is reduced.

Further, in the present invention, the peripheral thickness of the outer surface of the face portion of the glass panel in the diagonal axis direction is set to T.
E, when the center of the wall thickness _{T 0, 1.2 ≦ TE / T} 0 ≦
4.0, wherein the difference in transmittance between the center and the periphery of the face of the glass panel having the colored resin plate adhered to the outer surface is within 5%.

[0014]

The colored resin plate of the present invention has a gradually decreasing thickness from the center to the periphery, and therefore has a lower brightness at the center than at the periphery. When this colored resin plate is bonded to the outer surface of the glass panel, The decrease in luminance occurring around the face portion is eliminated, the difference in transmittance between the center and the periphery of the face portion is reduced (smaller), and the transmittances of the two can be approximated.

In consideration of explosion protection, when the peripheral thickness of the face portion of the glass panel in the diagonal axis direction is TE and the central thickness is T ₀ , TE / T ₀ is 1.2 or more. Even in this case, the difference in transmittance between the center and the periphery of the face portion after the colored resin plate is bonded can be suppressed to within 5%, and unevenness in image brightness can be substantially suppressed. . However, it is not preferable that TE / T ₀ be 4.0 or more, because the weight of the cathode ray tube becomes too large.

In the cathode ray tube according to the present invention, the outer surface of the face portion of the glass panel is concave from the periphery toward the center, and the colored resin plate adhered to the outer surface is:
Since it has a convex adhesive surface that fits on the outer surface of the face portion, a strong adhesive surface can be obtained. Moreover, since the outer surface of the colored resin plate is substantially flat, it is easier to see than a curved image. Further, that one surface of the colored resin plate is flat also has an advantage that it is easier to mold as compared to a case where both surfaces are curved surfaces.

The material of the colored resin plate in the present invention includes acrylic resin, polyethylene terephthalate resin,
Colored resins such as polypropylene resin, polycarbonate resin, polyvinyl chloride resin, polyvinylidene chloride resin, and polystyrene resin are suitable.

The material of the adhesive for bonding the colored resin plate to the outer surface of the face of the glass panel is as follows.
Transparent resins such as acrylic resins, unsaturated polyester resins, urethane resins, polyvinyl acetate, butadiene acrylonitrile rubber, and the like are preferred.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a cathode ray tube of the present invention will be described in detail based on embodiments.

FIG. 1 shows a cathode ray tube (21 inches) according to the present invention.
It is a partially broken schematic explanatory view showing, the glass panel 11,
A glass bulb is produced by sealing the funnel 12 and the neck 13, and the inside thereof is evacuated (10 ^−6).
torr).

The center thickness (T ₀ ) of the face portion of the glass panel 11 of the cathode ray tube in the diagonal axis direction is 10 m.
m, the peripheral thickness (TE) is 20 mm, the outer surface is concave from the periphery to the center by being pulled inward near the center of the face portion, and the transmittance at the center of the face portion is 80 mm. % And the peripheral transmittance is 70%.

A colored resin plate 15 is adhered to the outer surface of the face of the glass panel 11. The colored resin plate 15 is formed of an acrylic resin, and has an adhesive surface having a convex adhesive surface fitted to the outer surface of the face portion and a substantially flat outer surface. The center of this colored resin plate 15 (with a radius of about 100 mm from the center point)
Is 58%, and the transmittance of the other peripheral portions is 66%.

The adhesion of the colored resin plate 15 to the glass panel 11 is performed by applying an acrylic transparent adhesive to the entire adhesive surface of the colored resin plate 15 and then attaching it to the outer surface of the face of the glass panel 11. Was.

When the image of the cathode ray tube was observed, no unevenness was observed in the brightness, and the transmittance of the glass panel 11 to which the colored resin plate 15 was attached was measured. All were 46%.

As the transmittance of the above-mentioned glass panel, an average luminous transmittance at a wavelength of 380 to 780 mm measured by a spectrophotometer was applied.

[0026]

As described above, the cathode ray tube of the present invention uses a glass panel having different thicknesses at the center and the periphery of the face portion, but the transmittance of the transmittance at the center and the periphery of the face portion is increased by the colored resin plate. Since the difference is reduced, the difference in luminance between the center and the periphery of the image is reduced, and there is no unevenness in brightness.

Further, in the cathode ray tube of the present invention, since a colored resin plate is adhered to the outer surface of the glass panel, the increase in weight is remarkably small as compared with the case where a colored glass plate is used.

Further, the face portion of the glass panel in the present invention has an outer surface in which the thickness at the center is smaller than the thickness at the periphery and which is concave from the periphery toward the center.
Since a colored resin plate having a convex bonding surface that fits on the outer surface is bonded to the outer surface, a strong bonding surface is obtained.

Further, since the outer surface of the colored resin plate is a flat surface, there is an advantage that an image can be easily viewed.

[Brief description of the drawings]

FIG. 1 is a partially cutaway schematic explanatory view showing a cathode ray tube of the present invention.

FIG. 2 is a schematic explanatory view, partially broken away, showing a structure of a general cathode ray tube.

[Explanation of symbols]

 11 Glass panel 12 Funnel 13 Neck 15 Colored resin plate

Claims (3)

[Claims] A glass panel having a fluorescent film on an inner surface thereof;
A glass bulb consisting of a funnel forming the back of the glass panel and a neck for accommodating the electron gun is provided, and the inside of the glass bulb is maintained in a vacuum. It has an outer surface that is smaller than the periphery and is concave from the periphery toward the center, and a colored resin plate is adhered to the outer surface of the face portion, and the colored resin plate is fitted to the outer surface of the face portion It has a convex adhesive surface like this and a substantially flat outer surface, which reduces the difference in transmittance due to the difference in thickness between the center and the periphery of the face portion of the glass panel. CRT. 2. When the peripheral thickness of the face portion of the glass panel in the diagonal axis direction is TE and the central thickness is T ₀ , the expression 1.2 ≦ TE / T ₀ ≦ 4.0 is satisfied. The cathode ray tube according to claim 1, wherein 3. The cathode ray tube according to claim 1, wherein the difference in transmittance between the center and the periphery of the face portion of the glass panel having the colored resin plate adhered to the outer surface is within 5%.