JP2964939B2 - Color 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 shadow mask type color cathode ray tube, and more particularly to a color cathode ray tube having a shadow mask which has high mechanical strength and high electron beam transmittance and is suitable for high definition.

[0002]

2. Description of the Related Art As shown in FIG. 3, a shadow mask type color cathode ray tube is provided on an inner surface of a panel 1 on which an image is displayed in a direction perpendicular to a scanning line of an electron beam emitted from an electron gun 2. A phosphor screen 3 in which a number of vertically continuous three-color phosphor stripes are arranged in a row is formed. And
A substantially conical funnel 5 having a tubular neck 4 is connected to the panel 1 to form a vacuum vessel. Also,
Three electron guns 2 are mounted in the neck portion 4 in-line, and a deflection yoke 6 for deflecting the electron beam is mounted on the outer periphery of the funnel 5, and the electron beam is opposed to the fluorescent screen 3 on the inner surface of the panel 1. A shadow mask 8 having a through hole 7 for selective transmission is mounted. The shadow mask type color cathode-ray tube having the above-described configuration has the 3
The electron beam is deflected by a horizontal deflection magnetic field and a vertical deflection magnetic field formed by the deflection yoke 6, is scanned over the entire fluorescent surface of the fluorescent film 3, passes through the through holes 7 of the shadow mask 8, and emits the fluorescent light of the corresponding color. A color image is displayed by projecting on the body and exciting the phosphor to emit light.

As shown in FIG. 4, a normal shadow mask 8 is formed by arranging a plurality of through-holes 7 in which rectangular through-holes 7 are arranged at a constant pitch Pv in the vertical direction of the screen in a regular and horizontal manner. It is configured as a mosaic. The amount of the effective electron beam passing through each through-hole is less than 1/3 due to its mechanism. The remaining electron beam collides with the shadow mask and is converted into thermal energy. Heating causes a so-called doming phenomenon in which the central portion expands due to thermal expansion. JP 60
As a countermeasure against this, JP-A-148036 discloses that a low conductivity glass coating layer 9 is provided on the surface of the shadow mask 8 on the electron gun side as shown in FIG. A shadow mask type color cathode ray tube having a configuration in which a doming phenomenon is prevented by preventing the electron beam from being mislanding due to electrostatic deflection of the electron beam due to charging of the coating layer 9 is disclosed. Japanese Patent Laid-Open Publication No. 64-38941 discloses a shadow mask having a structure in which a doming suppressing material 9a is spray-coated on both surfaces of a shadow mask 8a and a conductive film 14 is formed thereon as shown in FIG. A color cathode ray tube is disclosed.

[0004]

However, in these conventional examples, since the vitreous material is applied to the electron gun side of the shadow mask, the electron beam scanned over the entire surface of the shadow mask is exposed to the vitreous material. In this case, a problem such as a partial loss of the coating occurs due to a temperature rise of the glass itself or a thermal cycle. In addition, non-uniformity of the vitreous property due to fluctuations and variations in the manufacturing process, and non-uniformity of the conductive film resulted in non-uniform charging of the vitreous substance, which caused problems such as the appearance of a non-uniform pattern on the screen. . In particular, in the latter case of FIG. 6, since the vitreous material is also applied to the phosphor screen side, not only the drawback of the case where the vitreous material is applied to the electron gun side cannot be solved, but also the man-hours are complicated in the manufacturing process. There are drawbacks in terms of cost and cost. Accordingly, the present invention has been proposed in order to solve the above-mentioned problems, and a glass coating layer is formed on the periphery of a large number of through holes of a shadow mask on the phosphor screen side of a shadow mask panel to form a shadow mask. The purpose of the present invention is to provide a color cathode ray tube which improves the mechanical strength of the color cathode ray tube, minimizes the problems caused by unnecessary charging as described above, and improves the landing accuracy by the electron beam convergence effect by forming a selective glass coating layer. And

[0005]

A panel having a phosphor screen of a group of phosphors having different emission colors, and a panel arranged in close proximity to the phosphor screen,
A color cathode ray tube comprising: a shadow mask having a large number of through-holes formed by etching; and an electron gun which is arranged on the opposite side of the phosphor screen with respect to the shadow mask and emits an electron beam for causing the phosphor group to emit light. An insulating glass coating layer is formed on a side of the etching peripheral portion of the through hole of the shadow mask facing the phosphor screen.

According to the above structure, in the shadow mask having a large number of through holes formed by the etching process, the peripheral portion of the thin and small through hole is reinforced with the glass coating layer, and the mechanical strength of the shadow mask is improved. I do. Moreover, this glass coating layer is only charged by secondary electrons emitted from the phosphor screen by the electron beam, and the electrostatic lens formed by this charging is used for convergence of the electron beam, and the electron lens on the phosphor surface Landing accuracy is improved by reducing the beam spot diameter. That is, since the insulating glass coating layer is formed on the periphery of the through-hole formed by etching, the through-hole region, which causes a reduction in strength, can be directly reinforced. In addition, since an electron lens effect can be obtained around the through hole, unnecessary portions are not made vitreous, and the manufacturing process can be simplified. Furthermore, by making the coefficient of thermal expansion of the glass coating layer smaller than the coefficient of thermal expansion of the shadow mask, a state in which compressive stress is applied to the fused glass around the shadow mask having the through-holes, which is the main cause of the strength reduction. , The strength of the shadow mask can be improved. In addition, by insulating the shadow mask and the electrically providing a conductive layer on the glass coating layer, it is possible to uniform the charged charge distribution in the coating layer, stable convergence force of the electrostatic lens with respect to the electron beam The electron beam spot diameter on the phosphor screen can be stably converged.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. The same parts as those in the conventional example are denoted by the same reference numerals, and description thereof will be omitted. As shown in FIG. 1, a shadow mask made of an invar alloy (coefficient of thermal expansion: 50.times.10@-7 / DEG C.) of a color cathode ray tube according to an embodiment of the present invention has a rectangular through hole 7 in the vertical direction of the screen. A large number of through-holes arranged at a constant pitch Pv are arranged in parallel and regularly in a horizontal direction so as to form a mosaic shape. The peripheral portion 7 of the through hole 7 on the surface of the shadow mask 10 facing the fluorescent screen 3
A glass coating layer 11 made of borosilicate glass (coefficient of thermal expansion: 45.times.10@-7 / DEG C.) is formed on a. further,
An aluminum conductor thin film 12 is formed on the glass coating layer 11. The coating layer 11 on these shadow masks 10 is formed as follows. For example, a glass slurry in which borosilicate glass powder is dispersed in a butyl acetate solution in which several percent of nitrocellulose is dissolved is applied to the main surface of the shadow mask 10 on the fluorescent screen 3 side by a spray method, and the shadow mask is mounted on a predetermined frame base. And put on 1
After calcining at about 00 ° C to remove the binder,
After passing through a furnace heated at about 40 ° C. for about 40 minutes, a smooth glass coating layer 11 is formed at the connection portion of the shadow mask 10. Next, a conductive thin film 12 of aluminum or the like is formed on the glass coating layer 11 of the shadow mask 10 on which the glass coating layer 11 has been formed by a method such as vacuum evaporation. In addition,
The method of selectively applying a vitreous material to the peripheral portion of the through-hole is, in advance, a method of forming a glass-applied layer by a photoresist method or the like, or after flowing the glass material on the shadow mask surface,
There is a method in which a gas flow is sent and pressed into the peripheral edge of the through hole so that the through hole is not blocked by ventilation from the opposite side.

According to this embodiment, the connecting portion of the shadow mask is reinforced by the glass coating layer, and a slight compressive stress is applied to the glass in a hardened state of the glass due to a difference in thermal expansion coefficient between the glass and the shadow mask. Can be added,
A shadow mask structure with improved mechanical strength can be provided. Then, as shown in FIG. 2, since the aluminum conductive thin film 12 electrically insulated from the shadow mask 10 is formed on the glass coating layer 11, the electron beam 13
The electron beam 13 is formed on the glass coating layer 11 on the periphery of the through hole 7 of the shadow mask 10 on the fluorescent screen 3 side by an electrostatic lens formed by being charged by secondary electrons emitted from the fluorescent screen 3.
Are converged and the electron beam spot diameter on the phosphor screen 3 is reduced, so that the landing margin (accuracy) is improved.

In the above, an example has been described in which a glass coating layer made of borosilicate glass and a conductive thin film made of aluminum are sequentially formed on the main surface on the phosphor screen side of a shadow mask made of an Invar alloy. However, the material of the shadow mask or the glass may be a combination of a cold-rolled steel sheet and a glass having a smaller coefficient of thermal expansion such as a lead borate glass than the shadow mask. Also,
An oxide layer may be interposed to improve the sealing property of the glass coating layer with the shadow mask, or a multilayer may be used.
Since the electrostatic lens is formed on the glass coating layer by charging, the convergence effect of the electron beam is also reduced as compared with the above-described example, but if the design is sufficient, a conductive thin film on the glass coating layer is provided. You don't have to.

[0010]

According to the present invention, the connecting portion of the shadow mask which is thin and has a small area is reinforced by the glass coating layer.
The mechanical strength of the shadow mask can be improved, and the electron beam is converged by an electrostatic lens formed by charging the glass coating layer on the periphery of the through-hole of the shadow mask. Since the size becomes smaller, the landing accuracy is improved. Therefore, it is possible to provide a color cathode ray tube having a shadow mask which has high mechanical strength and high electron beam transmittance and is suitable for high definition. Further, according to the present invention, without being irradiated to the glass by a large amount of electron beam occurring in the case of the conventional example,
Lifetime and reliability can be ensured, and the vitreous beam is selectively and effectively irradiated to the vitreous material in the peripheral beam shown in FIG. Improvements are made.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a shadow mask of a color cathode ray tube according to an embodiment of the present invention.

FIG. 2 is a sectional view of an essential part showing a converged state of an electron beam according to one embodiment of the present invention.

FIG. 3 is a configuration diagram of a general color cathode ray tube.

FIG. 4 is a perspective view of a shadow mask of a general color cathode ray tube.

FIG. 5 is a sectional view of a main part of a shadow mask of a conventional color cathode ray tube.

FIG. 6 is a sectional view of a main part of a shadow mask of another conventional color cathode ray tube.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Panel 2 Electron gun 3 Phosphor screen 7 Through-hole 7a Peripheral part 10 Shadow mask 11 Glass coating layer 12 Conductive thin film (conductive layer) 13 Electron beam

Claims (1)

(57) [Claims] 1. A panel having a phosphor screen of a group of phosphors having different emission colors, a shadow mask disposed in close proximity to the phosphor screen and having a large number of through holes formed by etching, An electron gun that emits an electron beam that causes the phosphor group to emit light, in a color cathode ray tube that is disposed on the opposite side, of the etching peripheral portion of the through hole of the shadow mask, on the side facing the phosphor screen.
Forming an insulating glass coating layer only on the insulating glass coating layer.
Laminated on the cover layer and electrically insulated from the shadow mask
A color cathode ray tube comprising a conductive layer formed thereon so as to make charge uniform .