JPH11265662A - Color cathode-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently emit an ultrasonic wave to the whole surface in ultrasonic cleaning and prevent a foreign matter from being left in a shadow mask structure by reducing the area of the flat porous bottom surface of a frame within the range never reducing the strength of the frame constituting the shadow mask structure. SOLUTION: The porous bottom part 12a of a frame 12 is formed so that the part excepting the corner part 12b and inner shield mounting part 12c of the frame 12 is narrowed as much as possible, compared with a conventional porous bottom 5a. According to this, ultrasonic vibration in ultrasonic cleaning is transmitted to a shadow mask in the upper part with being hardly shielded by the porous bottom part 12a, so that a foreign matter adhered to the shadow mask can be surely removed, and the removed foreign matter can be also easily removed from the frame 12. Even if the foreign matter is adhered within the porous bottom part 12a of the frame 12, it can be easily removed by vibrating the frame 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a perforated bottom structure of a frame in a mask structure of a color cathode ray tube having a shadow mask.

[0002]

2. Description of the Related Art The structure of a conventional color cathode ray tube having a shadow mask structure will be described with reference to FIG. In the figure, reference numeral 1 denotes a cathode ray tube bulb, in which a panel 1a having a fluorescent film 2 formed on an inner surface thereof and a neck portion 1b containing an electron gun 3 therein are connected to both sides of a funnel portion 1c. Reference numeral 4 denotes a shadow mask structure disposed in the cathode ray tube bulb 1, in which a shadow mask 6 is fixed to one end of a rectangular cylindrical frame 5 having a perforated bottom 5a. A spring 8 engaged with a stud pin 7 embedded in the inner periphery of the frame 5 is welded, and an inner shield 9 is fixed to the other end of the frame 5 by a connection pin 10.

After the shadow mask structure 4 is welded to the frame 5, the shadow mask structure 4 is immersed in a cleaning liquid and subjected to ultrasonic cleaning to remove foreign substances. When the black matrix film and the fluorescent film 2 of three primary colors are sequentially formed on the inner surface of the panel 1a, the shadow mask structure 4 is combined with the panel 1a, and is repeatedly attached and detached. Finally, the inner shield 9 is attached.

In this color cathode ray tube, an electron beam emitted from an electron gun 3 is deflected by a deflection yoke and passes through a shadow mask 6, though not shown, though not shown.
To display an image. In recent years, in the color cathode ray tube, the fluorescent film 2 has been miniaturized in order to increase the resolution of an image, and the electron beam transmission hole of the shadow mask 6 has also been miniaturized correspondingly.

[0005]

However, if foreign matter adheres to the shadow mask structure 4, the shadow mask 6 may be clogged or re-adhered to an undesired portion of the cathode ray tube bulb 1, causing a quality problem. Becomes Therefore, the shadow mask structure 4 is subjected to ultrasonic cleaning in a cleaning liquid prior to the operation of forming the fluorescent film 2.

However, in order to ensure the attachment of the inner shield 9 to the frame 5 of the shadow mask structure 4, the wide perforated bottom 5a is formed in a rectangular shape. Inner surface, perforated bottom 5
Ultrasonic vibrations are hardly transmitted to the portion blocked by a, and it has been difficult to reliably remove foreign matter attached to such a portion. In addition, the cleaning liquid containing foreign matter is circulated, and foreign matter is removed by a filter inserted in the circulation path. There was something to do.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems. The flat and perforated bottom of a frame constituting a shadow mask structure of a color cathode ray tube has a corner portion and an inner shield. The portion other than the portion to be connected is narrowed.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A color cathode ray tube according to the present invention
By reducing the area of the perforated bottom within the range that does not reduce the strength of the frame that composes the shadow mask structure, the ultrasonic wave passing through the perforated bottom can be efficiently applied to the entire surface of the shadow mask during ultrasonic cleaning. Can be applied well.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a partial sectional side view of a color cathode ray tube showing one embodiment of the present invention. In the drawing, the same parts as those in FIG. 4 are denoted by the same reference numerals, and the description thereof will not be repeated.

FIG. 1 differs from FIG. 4 in that
As shown in FIG. 2, the perforated bottom 12 a of the frame 12 is different from the conventional perforated bottom 5 a shown by a two-dot chain line in FIG.
2 corner portion 12b and inner shield mounting portion 1
The only difference is that the portion other than the vicinity of the center of the side of the rectangular perforated bottom portion 12a of the frame 12 which is 2c is made as narrow as possible. Specifically, the rectangular perforated bottom 12a of the frame 12
The part to which the inner shield 9 is connected is
In the center of four sides of the rectangular perforated bottom 12a. Note that the portion of the frame 12 to which the inner shield 9 of the rectangular perforated bottom 12a is connected is the one of the perforated bottom 12a.
Needless to say, a plurality of portions may be provided on the side.

As a result, as shown in FIG. 3, the ultrasonic vibration during the ultrasonic cleaning is transmitted to the shadow mask 6 almost without being blocked by the perforated bottom 12a as shown by the arrow in the figure. Therefore, the foreign matter adhering to the shadow mask 6 can be reliably removed, and additionally, the removed foreign matter can be easily removed from the inside of the frame 12. By vibrating, it can be easily removed.

As a result, quality problems such as withstand voltage characteristics caused by poor light emission of the fluorescent film due to foreign matter and redeposition on an undesired portion in the cathode ray tube bulb can be solved.

[0013]

As described above, according to the present invention,
By reducing the area of the perforated bottom within the range that does not reduce the strength of the frame that composes the shadow mask structure, the ultrasonic wave passing through the perforated bottom can be efficiently applied to the entire surface of the shadow mask during ultrasonic cleaning. Since it can be applied well, it is possible to prevent foreign matter from remaining on the shadow mask structure.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional side view of a color cathode ray tube showing one embodiment of the present invention.

FIG. 2 is a bottom view of a frame used for the cathode ray tube of FIG. 1;

FIG. 3 is a side sectional view of a shadow mask structure for explaining the operation and effect of the present invention.

FIG. 4 is a partial cross-sectional side view showing a conventional color cathode ray tube.

[Explanation of symbols]

 Reference Signs List 1 cathode ray tube bulb 1a panel 1b neck 1c funnel 2 fluorescent film 3 electron gun 6 shadow mask 7 stud pin 8 spring 9 inner shield 11 shadow mask assembly 12 frame 12a perforated bottom 12b corner 12c inner shield connection

Claims (4)

[Claims] 1. A color cathode ray tube in which a fluorescent film formed on the inner surface of a panel of a cathode ray tube bulb and a shadow mask fixed to one end of a cylindrical frame are opposed to each other and an inner shield is connected to the other end of the frame. A color cathode ray tube having a flat perforated bottom at an end, and a portion excluding a corner of the perforated bottom and a portion to which an inner shield is connected is made as narrow as possible. 2. A part to which the inner shield is connected,
2. The color cathode ray tube according to claim 1, wherein the color cathode ray tube is provided near the center of the side of the bottom of the rectangular hole of the frame. 3. The color cathode ray tube according to claim 2, wherein the portion to which the inner shield is connected is provided at the center of four sides of the rectangular hole-shaped bottom of the frame. 4. A part to which the inner shield is connected,
2. A color cathode ray tube according to claim 1, wherein a plurality of portions are provided on one side of the rectangular bottom of the frame.