JPH11283532A - Cathode-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cathode-ray tube in which a face part can be thinned, because high X-ray absorption coefficient can be given to a panel glass, without having it contain PbO in it, and which is satisfactorily explosion proof. SOLUTION: A reinforcement plate 15 of transparent resin (about 3 mm thickness) is pasted entirely on an outer surface of a face part of panel glass 11 through a transparent adhesive 16. This reinforcement plate 15 of transparent resin is made by chemically coupling and integrating lead in acrylic resin by copolymerization, and its lead content is 5-60 wt.%. A film thickness of a center part of the face part of the panel glass is not more than 15 mm.

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. The cathode ray tube has a panel glass 11 having a fluorescent film 10 on an inner surface thereof, and a funnel glass 12 having a funnel shape behind the panel glass 11.
And a glass bulb comprising a neck glass 13 for accommodating an electron gun as an envelope. In addition, a shadow mask 14 is provided so as to face the fluorescent film 10, and an electron beam emitted from an electron gun is applied to the fluorescent film 10 through the shadow mask 14, so that a front surface of the panel glass 11 ( The image is projected on the face)
At this time, if a braking X-ray is generated and leaks out of the tube through the panel glass 11, it has a bad effect on the human body.
The panel glass 11 is required to have a high X-ray absorption capacity.

At present, glass having an X-ray absorption coefficient of 28 to 29 cm ^-1 at a wavelength of 0.6 A is used as a material of a panel glass of a cathode ray tube. It contains SrO, BaO, ZrO _{2 and the} like. The X-ray absorption ability of the panel glass is determined by the X-ray absorption coefficient of the glass and the thickness of the glass. It needs to be raised.

[0004]

When the X-ray absorption coefficient of glass is increased for the purpose of reducing the thickness of the face portion of the panel glass, lead (PbO) has the highest X-ray absorption ability and is an effective component. However, glass containing PbO is not preferable because it causes coloring called browning when irradiated with an electron beam or X-ray.

It is widely known that lead is harmful to the human body. However, in recent years, when a cathode ray tube is disposed of, the cathode ray tube may be buried in the ground. There is concern that it may elute into the environment and contaminate the environment. Therefore, it is necessary to avoid containing PbO in the panel glass as much as possible from an environmental point of view.

In order to further increase the X-ray absorption coefficient of the panel glass while avoiding the inclusion of PbO, it is necessary to use SrO, BaO, ZrO ₂
It is necessary to contain more X-ray absorbing components such as the above. On the other hand, if the content of these components is too large, the liquidus temperature rises and the glass is apt to be devitrified, and the molding of the glass becomes difficult. Is not preferred.

The present invention has been made in view of such circumstances, and can provide a high X-ray absorption coefficient without containing PbO in a panel glass, so that the face portion can be made thinner. Moreover, it is an object to provide a cathode ray tube having excellent explosion-proof properties.

[0008]

A cathode ray tube according to the present invention is characterized in that a transparent resin reinforcing plate containing an X-ray absorbing substance is adhered to an outer surface of a face portion of a panel glass.

The cathode ray tube according to the present invention is characterized in that the X-ray absorbing substance is lead and the lead content in the transparent resin reinforcing plate is 5 to 60% by weight.

The cathode ray tube according to the present invention is characterized in that the thickness of the center of the face of the panel glass is 15 mm or less, and the radius of curvature of the outer surface of the face of the panel glass in the diagonal axis direction is 10000 mm or more. There is a feature.

[0011]

In the cathode ray tube of the present invention, a transparent resin reinforcing plate is attached to the outer surface of the face portion of the panel glass, so that implosion of the cathode ray tube can be prevented. Since the plate contains the X-ray absorbing substance, the transparent resin reinforcing plate improves the X-ray absorbing ability of the front part. Therefore, even if the thickness of the center portion of the face portion of the panel glass is set to 15 mm or less, a desired X-ray absorbing ability can be obtained, and the weight can be reduced.

As the X-ray absorbing substance in the present invention, lead is preferable because it has the highest X-ray absorbing ability.
When lead is used in this way, the lead content in the resin is 5%.
It is desirably set to 〜60% by weight. That is, when the lead content is less than 5% by weight, the X-ray absorption ability decreases,
This is because it becomes difficult to obtain a desired X-ray absorbing ability, while if it exceeds 60% by weight, the transparency and mechanical strength of the transparent resin reinforcing plate tend to decrease.

As the material of the transparent resin reinforcing plate, acrylic resin, polyethylene terephthalate resin, polypropylene resin, polycarbonate resin, polyvinyl chloride resin,
A transparent resin such as a polyvinylidene chloride resin and a polystyrene resin is preferable.

When the transparent resin reinforcing plate is mounted on the outer surface of the face portion of the panel glass, a spacer is arranged so as to maintain a certain gap between the panel glass and the transparent resin reinforcing plate, and a transparent adhesive is attached to the gap. Although it is possible to inject the adhesive and fix it, it is better to apply the transparent adhesive over the entire surface to which the transparent resin reinforcing plate is attached and then attach it to the face of the panel glass because workability is better. preferable.

In particular, when the radius of curvature in the diagonal axis direction of the outer surface of the face of the panel glass in the diagonal axis direction is 10,000 mm or more, the outer surface of the face of the panel glass becomes almost flat, and it is necessary to curve the transparent resin reinforcing plate. However, it is preferable because it can be easily adhered by a method of applying a transparent adhesive to a transparent resin reinforcing plate and bonding it.

As the material of the transparent adhesive in the present invention, a transparent resin such as acrylic resin, unsaturated polyester resin, urethane resin, polyvinyl acetate, butadiene acrylonitrile rubber is preferable.

When the cathode ray tube of the present invention is discarded, it is environmentally preferable to remove the transparent resin reinforcing plate attached to the panel glass before disposing.

[0018]

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

FIG. 1 is a partially cutaway schematic view showing a cathode ray tube (21 inches) according to the present invention. A glass bulb is produced by sealing a panel glass 11, a funnel glass 12 and a neck glass 13. Have been.

The panel glass 11 of this cathode ray tube is made of Si
O ₂ 61%, Al ₂₃ 2%, CaO 1%, SrO
8%, BaO 10%, ZrO ₂ 2%, Na ₂ O 7
_{%, K 2 O 8%,} CeO 2 0.5%, TiO 2 0.
The face portion has a thickness of 10 mm at the center in the diagonal direction, a peripheral thickness of 20 mm, and a radius of curvature of the outer surface of the face portion in the diagonal direction of 100 mm.
000 mm.

A transparent resin reinforcing plate 15 (thickness: 3 mm) is provided on the entire outer surface of the face portion of the panel glass 11.
Are adhered by a transparent adhesive 16. The transparent resin reinforcing plate 15 is produced by chemically bonding and integrating lead in an acrylic resin by copolymerization, and has a lead content of 30% by weight.

The transparent resin reinforcing plate 15 is attached to the panel glass 11 by applying an acrylic transparent adhesive to the entire surface to which the transparent resin reinforcing plate 15 is attached and then to the outer surface of the face of the panel glass 11. It was done by pasting.

When the X-ray absorption characteristics of the image surface of the cathode ray tube to which the transparent resin reinforcing plate was attached were examined, the attenuation rate was 1 / (9 × 10 ¹⁴ ).

Next, a panel glass similar to the above was prepared, a cathode ray tube was prepared without attaching a transparent reinforcing resin plate to the panel glass, and the X-ray absorption characteristics of the image plane were measured.
The attenuation rate was 1 / (4 × 10 ¹² ), and the X-ray absorbing ability was inferior to that of the cathode ray tube to which the transparent reinforcing resin plate was attached.

The above-mentioned X-ray absorption characteristics are calculated from the mass absorption coefficients of the panel glass and the transparent resin reinforcing plate.

[0026]

As described above, the cathode ray tube of the present invention can prevent implosion because the transparent resin reinforcing plate is attached to the outer surface of the face portion of the panel glass. Since it contains an X-ray absorbing substance, a high X-ray absorbing ability can be imparted even when a panel glass containing no PbO is used. Therefore, the thickness of the face portion of the panel glass can be reduced, and the weight can be reduced.

[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 Panel glass 12 Funnel glass 13 Neck glass 15 Transparent reinforcing resin plate 16 Transparent adhesive

Claims (4)

[Claims] 1. An X surface is formed on the outer surface of a face of a panel glass.
A cathode ray tube comprising a transparent resin reinforcing plate containing a radiation absorbing material attached thereto. 2. The cathode ray tube according to claim 1, wherein the X-ray absorbing substance is lead, and the lead content in the transparent resin reinforcing plate is 5 to 60% by weight. 3. The cathode ray tube according to claim 1, wherein the thickness of the center of the face portion of the panel glass is 15 mm or less. 4. The cathode ray tube according to claim 1, wherein a radius of curvature in a diagonal axis direction of an outer surface of the face portion of the panel glass is 10,000 mm or more.