JPH0218919Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a color cathode ray tube, and particularly to a black conductive film formed on the inner surface of the panel.

[Technical background of the invention and its problems] In a color cathode ray tube, a bulb is formed by sealing a panel with a phosphor screen formed on its inner surface and a funnel in which an electron gun is sealed inside the neck.
As shown in the figure, a shadow mask 3 is disposed facing the phosphor screen 2 on the inner surface of the panel 1 at a predetermined distance, and the peripheral edge of the shadow mask 3 is fixed to a mask frame 4. The shadow mask 3 is disposed by fitting a holder (not shown) welded to the frame into a pin (not shown) protruding from the inner surface of the panel. Black conductive films 6 and 7 are coated on the inner surfaces of the funnel 5 and the panel 1, respectively, and an inner shield 8 is attached to the frame 4. As shown in FIG. 3, this inner shield 8 is provided with openings 9 at each corner. Further, a getter 10 is disposed in a predetermined manner within the tube, and a ring 11 containing a getter material is attached to the distal end of the getter 10.

When such a color cathode ray tube is operated, voltages are applied to each part as prescribed, but a problem may occur in which abnormal light emission is observed at the outer corner of the phosphor screen. In this case, the peripheral edge of the panel is in a state as shown in FIG. That is, the getter is scattered through the opening 9 at the corner of the inner shield, and a vapor deposited getter film 13 is formed on the panel surface, the thick part 13A of which is the umbra, and the thin part 1
3B is a penumbra, but this part of the vapor deposited film and the black conductive film 14 extending from the phosphor screen 2 do not overlap, which causes the above-mentioned problem. be. Under these conditions, when the cathode ray tube is operating, some of the electron beams enter through the openings in the corners of the inner shield and hit the getter vapor deposited film formed on the inner surface of the panel, accumulating electrons and lowering the potential. Therefore, electrons are emitted toward the frame, panel, and funnel, which are at + potential, and at this time, they are also emitted to the phosphor screen as shown by the arrow, causing the phosphor to emit light. Deteriorates image characteristics. In this way, the problem that the phosphor emits light due to electrons that do not pass through the holes in the shadow mask continues for a long time, resulting in poor characteristics and the failure of the cathode ray tube. There was a demand for something that would not cause such problems.

[Purpose of the invention] The present invention was made in consideration of the above-mentioned points, and its purpose is to provide a color cathode ray tube with good characteristics that does not cause abnormal light emission that impairs image characteristics over a long period of time. .

[Summary of the invention] In the color cathode ray tube of the invention, the funnel-side end of the black conductive film formed on the inner surface of the panel passes through the openings at the corners of the inner shield and passes through the umbra of the getter vapor-deposited film formed on the inner surface of the panel. A black conductive film is formed so as to be in contact with the panel, and the occurrence of abnormal light emission from the phosphor screen formed on the inner surface of the panel can be prevented and the characteristics can be improved.

[Embodiments of the invention] Examples of the invention will be described below with reference to the drawings. As shown in FIG. 1, the black conductive film 21 formed on the inner surface of the panel 1 has a funnel-side tip 2.
1A is formed extending toward the funnel 5 side so as to come into contact with the umbral portion 13A of the vapor deposited film formed on the inner surface of the panel 1 through the opening 9 at the corner of the inner shield 8. In other words, the extension point 22 on the inner surface of the panel of the line connecting the panel side end of the getter ring and the panel side end of the opening in the inner shield, and the funnel side end of the getter ring and the funnel side end of the opening in the inner shield. The umbra part of the vapor deposited film is formed on the panel surface between the extension point 23 of the connecting line onto the inner surface of the panel, and conduction is established through contact between this part and the black conductive film, and fluorescence is emitted. Abnormal light emission on the surface can be prevented.

[Effects of the invention] As described above, in the color cathode ray tube of the invention, electrical conduction is established between the black conductive film on the inner surface of the panel and the vapor deposited film formed on the inner surface of the panel through the openings in the corners of the inner shield. It is possible to prevent the phosphor screen from emitting abnormal light for a long time due to electron emission from this vapor-deposited film, thereby improving the characteristics of color cathode ray tubes and further improving the manufacturing yield. It is something.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing the main parts of the color cathode ray tube of the present invention, Fig. 2 is an explanatory view showing a part of the structure of the color cathode ray tube, Fig. 3 is a perspective view of the inner shield, and Fig. 4 is the peripheral portion of the panel. FIG. 1... Panel, 2... Fluorescent screen, 3... Shadow mask, 4... Mask frame, 5... Funnel, 8... Inner shield, 9... Corner opening of inner shield, 21... Inner surface of panel 13... Getter vapor deposited film, 13A... Umbrella portion of getter vapor deposited film.

Claims (1)

[Scope of utility model registration request] A getter disposed inside the funnel and having a ring at the tip, an inner shield attached to a frame that fixes a shadow mask disposed opposite to the fluorescent screen on the inner surface of the panel, and a getter formed on the inner surface of the funnel and panel. In a color cathode ray tube including a black conductive film, a funnel-side end of the black conductive film formed on the inner surface of the panel connects the panel-side end of the getter ring and the panel-side end of the corner opening of the inner shield. A color cathode ray tube characterized by being located further toward the funnel than the inner surface of the panel, which is an extension of the tube.