JPH06267447A - Color cathode ray tube - Google Patents

Abstract

(57) [Abstract] [Purpose] A sufficient tension is applied to the grill to reduce electron beam landing mistakes and to reduce the overall weight of the shadow mask structure. [Structure] Shadow mask structure 7 and mask frame 9
a, 9b and a large number of grilles 8a stretched between the mask frames, and a hollow portion 8d having a concave cross section is provided in the grill portion over the entire length of at least one side face in the longitudinal direction. [Effect] Since sufficient tension is applied to the grills, thermal expansion due to collision of electron beams does not cause displacement in the electron beam passage apertures formed between the grills.
No reduction in color purity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color cathode ray tube, and more particularly to a color cathode ray tube having a grill type shadow mask.

[0002]

2. Description of the Related Art A color cathode ray tube which is widely used at present is a so-called shadow mask type color cathode ray tube. The shadow mask provided in the color cathode ray tube has three electron beams emitted from an electron gun, which are divided into the inner surface of the panel and are divided into three phosphors of red, green, and blue, which are applied to the shadow mask to project. The purpose is to selectively control the path of each electron beam.

This type of shadow mask generally has a thin plate of iron or an iron-nickel alloy having a small coefficient of thermal expansion and has a round hole, a rectangle, or a comb-shaped electron beam passage hole, and the shadow is formed on the inner surface of the panel. The phosphors are formed by being divided as described above in a shape corresponding to the shape of the electron beam passage hole of the mask. A shadow mask having a round hole will be referred to as a dot shadow mask, a shadow mask having a rectangular shape will be referred to as a slot shadow mask, and a shadow mask having a blind electron beam passage hole will be referred to as a grill shadow mask.

Generally, the dot type shadow mask and the slot type shadow mask are often formed in a spherical shape,
The grill-type shadow mask is held in a cylindrical shape (cylindrical) by applying vertical tension. The temperature of the shadow mask rises due to the collision of the electron beam during the operation of the cathode ray tube, the position of the electron beam passage hole is displaced by the thermal expansion, and the landing mistake to the phosphor occurs to lower the color purity.

In recent years, the demand for high-definition display has been strengthened in the cathode ray tube, and as the accuracy of image display has increased, the fluorescent screen on the phosphor screen due to the displacement of the electron beam passage hole due to the thermal expansion of the shadow mask described above. The need to highly suppress the deviation of the landing position of the electron beam has become stronger and stronger. In order to reduce the above-mentioned thermal expansion, expensive iron-nickel alloys having a small thermal expansion coefficient are used as a constituent material of the shadow mask, or the shadow mask is tensioned and held by tensioning the mask frame. .

In a case where a large number of strips (grills) are stretched and held by tension in the vertical direction of the image display surface such as a grill type shadow mask, the mask frame holding the grills can withstand the tension. However, there is a problem in that the weight is increased and the grill vibrates greatly due to an external impact and the reproduced image is adversely affected.

Further, as the weight of the shadow mask structure increases, it is necessary to strengthen the support structure of the shadow mask structure.
There is also a problem in that the entire color cathode ray tube becomes heavy and hinders handling. It should be noted that as a disclosure of the prior art related to this type of technology, for example, US Pat.
No. 73283 can be mentioned.

[0008]

As described above, in the prior art, when a large number of grilles constituting a grill type shadow mask are vertically held on the image display surface and are cylindrically held in the mask frame, the mask is used. The frame is required to have sufficient mechanical rigidity to withstand the above-mentioned tension and has a drawback that the weight increases.

Further, if the rigidity of the mask frame is reduced in order to reduce the weight of the mask frame, there is a problem that sufficient tension cannot be applied to the grill. In general, a grill type shadow mask, like a dot type or slot type shadow mask, applies photoresist to a thin plate of thin iron or iron-nickel alloy, and bake it into a predetermined pattern.
After that, a large number of grills are formed by etching, and the slits formed between the grills are used as electron beam passage holes.

To lighten the shadow mask structure including the mask frame, the mask frame may be lightened and the thickness of the grill may be reduced, but the iron plate forming the grill is thinly rolled to a required size with a certain thickness. However, if it is too thin, it is difficult to handle during etching. An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a color cathode ray tube in which landing mistakes of an electron beam are reduced by applying sufficient tension to a grill and the shadow mask structure has a reduced total weight. Especially.

[0011]

In order to achieve the above object, the present invention comprises a panel having a phosphor screen formed on its inner surface, a neck for accommodating an electron gun, and a funnel for connecting the panel and the neck. In a color cathode ray tube comprising a vacuum envelope and at least a shadow mask structure having a grill type shadow mask suspended in the panel,
The shadow mask structure comprises a mask frame and a plurality of grills stretched between a pair of opposing frames of the mask frame, and the grill portion has a hollow portion having a concave cross section on at least one side surface in the longitudinal direction thereof. Is provided.

[0012]

As described above, the grill type shadow mask is
A tension is applied in the extension direction (vertical direction) of the grill between opposing sides of the mask frame, and the mask frame is cylindrically fixed and held. With the above configuration of the present invention, the substantial thickness of the grill can be reduced, and sufficient tension can be applied to the grill without imposing a heavy load on the mask frame. Therefore, the mask frame is not required to have high rigidity, and the weight can be reduced.

Since sufficient tension is applied to the grills, thermal expansion due to collision of electron beams does not cause displacement in the electron beam passage apertures formed between the grills.
No reduction in color purity. Further, the entire shadow mask structure is lightened, and the vibration of the grill due to an external impact is also reduced.

[0014]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 shows a color cathode ray tube 1 of the present invention.
1 is a schematic cross-sectional view for explaining an embodiment, where 1 is a panel and 2 is
Is a funnel, 3 is a neck, 4 is an electron gun, 5 is a deflection yoke, 6 is a fluorescent screen, 7 is a shadow mask structure, 8 is a shadow mask consisting of many grills, 9a and 9b are mask frames, and 10a (10b is a figure Not shown) is a support frame.

In the figure, the shadow mask structure 7 comprises a shadow mask 8 comprising a large number of grills stretched by applying tension to mask frames 9a and 9b fixed by a pair of support frames 10a (10b) at predetermined intervals. It will be fixed. In this configuration, the three electron beams R, G, B emitted from the electron gun 4 are deflected by the deflection yoke 5 in two directions, horizontal and vertical, between the grilles forming the shadow mask 8 of the shadow mask structure 7. The formed slit is subjected to color selection as an electron beam passage hole and projected onto a predetermined phosphor forming the phosphor screen 6.

Each electron beam R, G, B is driven by a drive signal given to a control electrode constituting an electron gun, and a predetermined color image is expressed by a predetermined current ratio of the three electron beams. The shadow mask structure 7 is suspended and supported on the side wall of the panel 1 by a spring suspension mechanism. FIG. 2 is a perspective view of a shadow mask structure attached to the color cathode ray tube of the present invention, in which the same reference numerals as those in FIG. 1 correspond to the same parts, 8a is a grill, 8b is a slit, 9 is a vibration-proof wire, and 11a. , 11b are wire supports.

In the figure, the shadow mask structure 7 is
A shadow mask 8 including a large number of grills 8a fixed to the mask frames 9a and 9b fixed by a pair of support frames 10a and 10b at a predetermined interval by applying tension.
Consists of. The shadow mask 8 has mask frames 9a and 9b at the connecting portions 8c of the grilles 8a at both ends in the longitudinal direction.
It is welded and fixed by applying tension to.

The tension applied to the grill 8a of the shadow mask 8 is supported by the support frames 10a and 10b which support the mask frames 9a and 9b at predetermined intervals. The slit 8b formed between the grilles 8a constitutes an electron beam passage hole, and the vibration-proof wire 9 supported by the wire supports 11a and 11b is elastic in the direction (lateral direction) intersecting the extending direction of the grill 8a. It is touched.

FIG. 3 is an explanatory view of the main structure of the shadow mask structure mounted on the color cathode ray tube of the present invention, and FIG. 4 is a sectional view taken along line AA of FIG. In the figure, the shadow mask 8 is composed of a large number of grills 8a arranged in parallel, and the slits 8b formed between the adjacent grills 8a form electron beam passage holes.

A cavity 8d having a concave cross section is formed on the surface of the grill 8a on the electron gun side, and the thickness of the grill 8a is substantially reduced by the formation of the cavity 8d.
The concave cavity portion 8d is formed by etching. When the original thickness of the shadow mask 8 is 0.10 mm, the width W ₁ of the grill 8a on the fluorescent screen side is 0.125 m.
m, the width W ₂ on the electron gun side is 0.225 mm, the gap W ₃ between the grills is 0.3 mm, and the width W ₄ of the cavity 8d is 0.125.
mm, and the depth d thereof is 0.05 mm.

In this structure, the substantial thickness of the grill 8a can be reduced by about 28%. FIG. 5 is an explanatory view of the structure of the fixed portion of the shadow mask structure attached to the color cathode ray tube of the present invention. In the figure, a pair of mask frames 9
a (9b) is supported in parallel by a pair of support frames 10a (10b) provided in the left-right direction of the screen, and the shadow mask 8 is provided between the pair of mask frames 9a (9b).
Are welded and fixed in tension.

On the electron gun side of the grill 8a forming the shadow mask 8, a cavity 8d having the above-mentioned concave cross section is formed. Due to the hollow portion 8d, the plate thickness of the grill 8a is substantially reduced, and sufficient tension can be achieved with less tension than conventional. Therefore, the mask frame 9a (9b)
Also, the rigidity of the support frame 10a (10b) can be reduced, and the weight of the entire shadow mask structure can be reduced.

The cavity 8d formed in the grill 8a may be provided on the fluorescent screen side instead of the one provided on the electron gun side, and may be provided on both the electron gun side and the fluorescent screen side. . As described above, according to this embodiment, the thickness of the grill can be substantially reduced, and the weight of the shadow mask structure can be significantly reduced.

It is needless to say that the present invention can be applied to the slot type shadow mask as disclosed in US Pat. No. 4,973,283 described in the section of the prior art.

[0025]

As described above, according to the present invention,
It is possible to provide a color cathode ray tube using a grill type shadow mask structure having an excellent function of solving the problem of the conventional technique that a heavy mask frame has to be used.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view illustrating one embodiment of a color cathode ray tube of the present invention.

FIG. 2 is a perspective view of a shadow mask structure attached to the color cathode ray tube of the present invention.

FIG. 3 is a plan view of relevant parts for explaining an embodiment of the shadow mask structure mounted on the color cathode ray tube of the present invention.

FIG. 4 is a cross-sectional view taken along the line AA of FIG. 3 for explaining an embodiment of the shadow mask structure mounted on the color cathode ray tube of the present invention.

FIG. 5 is a cross-sectional view of an essential part for explaining a structure of a fixed portion of the shadow mask structure of one embodiment of the shadow mask structure mounted on the color cathode ray tube of the present invention.

[Explanation of symbols]

 1 panel 2 funnel 3 neck 4 electron gun 5 deflection yoke 6 fluorescent screen 7 shadow mask structure 8 grill type shadow mask 8a grill 8b slit 8d cavity 9 vibration isolation wire 9a, 9b mask frame 10a, 10b support frame 11a, 11b wire support body.

Claims (1)

[Claims] 1. A grill type suspended in the panel, comprising a vacuum envelope comprising a panel having a phosphor screen formed on the inner surface thereof, a neck accommodating an electron gun, and a funnel connecting the panel and the neck. In a color cathode ray tube having at least a shadow mask structure having a shadow mask, the shadow mask structure is composed of a mask frame and a plurality of grills stretched between a pair of opposing frames of the mask frame. A color cathode ray tube, characterized in that a hollow portion having a concave cross section is provided on at least one side surface in the longitudinal direction thereof.