JPH05190111A - Cathode ray tube - Google Patents

Abstract

PURPOSE:To suppress the breakage of a neck and the discharge of gas from an electrode at an electron beam discharge edge part by suppressing the temperature rise of the electrode at the electron beam discharge edge part. CONSTITUTION:A cathode ray tube has a plurality of bulb spacers 33 which are installed on an electrode 29 at the electron beam discharge edge part of an electron gun 28, and brought into pressure contact with the inner surface of a neck through an inside electric conductive film 26 which is coating-formed on the inner surface of the neck 25, and the bulb spacer is constituted of four bulb spacers arranged in the vertical symmetrical form with respect to a horizontal axis which crosses at right angle with the tube axis. Four bulb spacers 33 are installed at the position in the equal angle of 45 deg. or less from the vertical axis which crosses at right angle with the tube axis, around the tube axis.

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, and more particularly to a cathode ray tube having an improved mounting method of a valve spacer for supporting an electron beam emitting end of an electron gun.

[0002]

2. Description of the Related Art Generally, in a cathode ray tube, an electron gun is arranged in a neck of an envelope, and an electron beam emitted from this electron gun is generated by a deflection yoke mounted outside the envelope. It is formed in a structure for displaying an image by horizontally and vertically scanning a phosphor screen formed on the inner surface of the face plate of the envelope by deflecting by a vertical deflection magnetic field.

The electron gun is formed in a structure in which a cathode, a heater for heating the cathode, and a plurality of electrodes arranged in the phosphor screen direction so as to be adjacently arranged on the cathode are integrally fixed by an insulating support rod, The cathode side is fixed and supported by a stem pin that hermetically penetrates the stem that seals the neck end, and the electron beam emitting end is
It is attached to the electrode at the electron beam emitting end and is supported by a plurality of valve spacers that are pressed against the inner surface of the neck.

FIG. 4 shows the structure for supporting the above-mentioned electron beam emitting end portion for a color picture tube. The electron beam emitting end of the electron gun 1 of this color picture tube is composed of a convergence cup 2, and a plurality of valve spacers 3 (four in the illustrated example) are attached to the outer surface of the convergence cup 2 at equal intervals. The inner surface of the funnel-shaped funnel 4 of the envelope is pressed against the inner surface of the neck 5 through the inner conductive film 6 formed by coating from the inner surface of the large-diameter portion to the inner surface of the adjacent portion of the neck 5.

Reference numeral 7 is a getter attached to the convergence cup 2, and 8 is a deflection yoke attached to the outside of the envelope.

The valve spacer 3 not only guides the high voltage supplied through the anode terminal provided on the funnel 4 and the internal conductive film 6 to the high voltage application electrode of the electron gun for accelerating and focusing the electron beam, but also The electron beam emitting end of the gun 1 is supported, the electron gun 1 is held coaxially with the tube axis (Z axis), and the shock and vibration applied to the color picture tube are absorbed.
It has the function of preventing the position shift of the electron gun 1 due to the impact and vibration.

Therefore, from the viewpoint that the transmission of the shock and vibration applied to the color picture tube to the electron gun 1 is attenuated, the valve spacer 3 is used in a large number and the shock and vibration from all directions are effective. It is good to absorb into. However, when the number of used tubes is large, internal conductive due to friction occurs when the color gun is manufactured, when the electron gun 1 is sealed in the neck, and after impact or vibration is applied to the completed color picture tube after the electron gun is sealed. The film 6 peels off, and the particles of the peeled internal conductive film adhere to the electrodes of the electron gun 1 and the like, and the withstand voltage characteristics deteriorate. Therefore, the electron beam emitting end of the electron gun 1 is normally supported by 3 to 4 valve spacers 3.

However, if a plurality of valve spacers 3 are attached to the convergence cup 2 at the electron beam emitting end like the color picture tube, the convergence cup 2 at the electron beam emitting end usually comes close to the deflection yoke 7. As shown in FIG. 5, an eddy current in the direction of arrow 10 that cancels the change of the deflection magnetic field 9 (mainly the horizontal deflection magnetic field) generated by the deflection yoke is generated in the convergence cup 2 as shown in FIG. In addition to the rise, the valve spacer 3 is arranged in the region of the strong deflection magnetic field 9 generated by the deflection yoke.
A large eddy current in the direction of arrow 11 flows in the closed circuit formed by the cup 2 and the inner conductive film 6, and the eddy current causes the temperature of the convergence cup 2 to rise further.

When the electron gun is moved closer to the phosphor screen to reduce the magnification of the electron gun in order to improve the focus characteristics, the electron gun is closer to the deflection yoke.
Under the influence of the strong deflection magnetic field, the temperature rises more greatly. Therefore, defects such as breakage of the neck near the electrode whose temperature has risen and electron emission characteristics of the cathode deteriorate due to gas emission from the electrode or the like occur.

[0010]

As described above, the electron gun of the cathode ray tube has a plurality of electrodes which are in pressure contact with the inner surface of the neck through the inner conductive film formed by coating on the inner electrode of the electron beam emitting end of the electron gun. Valve spacers are attached, and the electron beam emission ends are supported by the valve spacers.

However, when a plurality of valve spacers are attached to and supported by the electrode at the electron beam emitting end as described above, the electrode at the electron beam emitting end is usually located close to the deflection yoke, and therefore the electron beam emitting electrode is emitted. Not only does the eddy current in the direction of canceling the change of the deflection magnetic field generated by the deflection yoke generate on the electrode at the end portion to raise the temperature, but the valve spacer is arranged in the region of the strong deflection magnetic field generated by the deflection yoke. As a result, a large eddy current flows in the closed circuit formed by the valve spacer, the electrode at the electron beam emission end and the internal conductive film, and the temperature at the electrode at the electron beam emission end is further increased by this eddy current. become.

When the electron gun is moved closer to the phosphor screen to reduce the magnification of the electron gun in order to improve the focus characteristics, the electron gun comes closer to the deflection yoke, and thus the influence of the strong deflection magnetic field causes Causes a greater temperature rise. Therefore, the neck near the electrode whose temperature has risen is damaged, or gas is released from the electrode or the like, which causes a defect such as deterioration of electron emission characteristics of the cathode.

The present invention has been made to solve the above-mentioned problems, and the electrode at the electron beam emission end of the electron gun is arranged close to the deflection yoke, and the electrode at the electron beam emission end is Even when placed in a strong deflection magnetic field generated by the deflection yoke, a closed circuit formed by a plurality of valve spacers attached to the electrodes at the electron beam emission end, electrodes at the electron beam emission end, and an internal conductive film is formed. The purpose is to reduce the flowing eddy current and suppress the temperature rise of the electrode at the electron beam emission end.

[0014]

The neck of an envelope is attached to an electrode of an electron beam emitting end of an electron gun, and an inner conductive film formed by coating is formed on the inner surface of the neck. In a cathode ray tube having a plurality of valve spacers pressed against the inner surface, the valve spacers are four valve spacers arranged vertically symmetrical with respect to a horizontal axis orthogonal to the tube axis. It was mounted at an equiangular position of less than 45 ° from the vertical axis orthogonal to the tube axis with the axis as the center.

[0015]

As described above, the valve spacers are four valve spacers arranged vertically symmetrically with respect to the horizontal axis orthogonal to the tube axis, and these four valve spacers are respectively connected to the tube axis about the tube axis. When installed at positions equiangularly less than 45 ° from the orthogonal vertical axes, it is possible to reduce the horizontal deflection magnetic field that crosses the closed circuit formed by these valve spacers, the electron beam emitting end electrodes of the electron gun, and the internal conductive film. As a result, the eddy current flowing in the closed circuit can be reduced and the temperature rise of the electrode at the electron beam emission end can be suppressed.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described based on embodiments with reference to the drawings.

FIG. 1 shows a color picture tube which is one of the embodiments. This color picture tube has an envelope composed of a panel 20 and a funnel-shaped funnel 21, and a phosphor screen 22 composed of a three-color phosphor layer that emits blue, green, and red is provided on the inner surface of the panel 20. A shadow mask 23 having a large number of electron beam passage holes formed therein is disposed so as to face the phosphor screen 22. On the other hand, an internal conductive film 26 is formed by coating from the inner surface of the large-diameter portion 24 of the funnel 21 to the inner surface of the adjacent portion of the neck 25. In the neck 25 of the funnel 21, three electron beams 27B, 27G, 27R
An electron gun 28 that emits is emitted. Then, the three electron beams 27B, 27G, and 27R emitted from the electron gun 28 are generated by the horizontal and vertical deflection magnetic fields generated by the deflection yoke 30 mounted outside the boundary between the large-diameter portion of the funnel 21 and the neck 25. The phosphor screen 22 is deflected and horizontally and vertically scanned to form a structure for displaying a color image.

The electron gun 28 comprises a cathode, a heater for heating the cathode, and a plurality of electrodes which are sequentially arranged on the cathode so as to be adjacent to each other and are integrally fixed by an insulating support. The cathode side of the electron gun 28 is mounted and supported by a stem pin 32 that hermetically penetrates a stem 31 that seals the end of the neck 25, and the electron beam emitting end is located near the deflection yoke 30. It is supported by four valve spacers 33 attached to the cup 29 and pressed against the inner surface of the neck 25 through the inner conductive film 26 of the neck 25.

The four valve spacers 33 are shown in FIG.
As shown in (b), a vertical axis (Y axis) that is vertically symmetrical with respect to a horizontal axis (X axis) orthogonal to the tube axis (Z axis) and that is orthogonal to the tube axis about the tube axis. ) Is less than 45 ° and is attached at a position of 30 ° or more.

In FIG. 1, 34 is a getter attached to the convergence cup 29, and 35 is an anode terminal.

By the way, if four valve spacers 33 are attached to the convergence cup 29 which is the electrode at the electron beam emission end of the electron gun 28 as described above, the support of the electron beam emission end of the electron gun 28 is deteriorated. Deflection yoke without
The temperature rise of the electrode at the electron beam emitting end portion due to the deflection magnetic field of 30 can be significantly suppressed.

That is, when the four valve spacers 33 are arranged vertically symmetrical with respect to the horizontal axis as described above, FIG.
As shown in (a), the horizontal deflection magnetic field 36 generated by the deflection yoke is substantially parallel to the vertical axis, and as shown in (b), the plane of the convergence cup 29 intersects with the horizontal deflection magnetic field 36. An eddy current indicated by arrow 37 is generated at. Further, in FIG. 3 (a), four valve spacers 33 are attached to 33a, 33b,
As shown separately from 33c and 33d, a closed circuit formed by two valve spacers 33a and 33d facing each other across the vertical axis, a convergence cup 29 and an internal conductive film 26,
Also, an eddy current flows in a closed circuit formed by the two valve spacers 33b and 33c, the convergence cup 29, and the inner conductive film 26, and the eddy current indicated by the arrow 39 generally flows.

In this case, the eddy current flowing through the closed circuit is
A plane including the tube axis and the horizontal axis of this closed circuit (XZ plane)
The larger the projected area onto the plane, the larger the projected area. Therefore, in order to reduce this eddy current, the projected area onto the plane including the tube axis and the horizontal axis of the closed circuit should be made as small as possible. Therefore, when the four valve spacers 33a, 33b, 33c, 33d are arranged vertically symmetrically with respect to the horizontal axis as described above, the horizontal deflection magnetic fields 36a, 33b, 33c and 33d are substantially parallel to the vertical axis. And two closed circuits (valve spacers 33a and 33d, a closed circuit formed by the convergence cup 29 and the internal conductive film 26) and valve spacers 33b and 33c that are parallel to each other and are formed above and below the horizontal axis. It is possible to make the size of the closed circuit formed by the convergence cup 29 and the internal conductive film 26 the same, and reduce the eddy current efficiently,
In particular, by arranging the valve spacers 33a, 33b, 33c, 33d at positions less than 45 ° from the vertical axis with the tube axis as the center, the support of the electron beam emitting end of the electron gun 28 is not deteriorated. The area of the closed circuit can be reduced, the eddy current generated by the horizontal deflection magnetic field 36 of the deflection yoke can be reduced, and the temperature rise of the convergence cup 29 can be suppressed.

On the other hand, regarding the vertical deflection magnetic field of the deflection yoke, since the vertical deflection magnetic field generally has a lower frequency than the horizontal deflection magnetic field 36, not only the eddy current generated in the convergence cup 29 but also the valve spacer 33 and the convergence magnetic field are generated.
Two closed circuits formed by the cup 29 and the internal conductive film 26 (in this case, the valve spacers 33a and 33b, the closed circuit formed by the convergence cup 29 and the internal conductive film 26, and the valve spacers 33c and 33d). And convergence
The eddy current generated in the closed circuit formed by the cup 29 and the inner conductive film 26) is also extremely small, and has almost no effect on the rise in temperature of the convergence cup 29.

If the angle θ from the vertical axis centering on the tube axes of the four valve spacers 33 becomes smaller than about 30 °, the support of the electron beam emitting end portion deteriorates.
At least about 30 ° is necessary.

Therefore, as described above, the four valve spacers 33 are vertically symmetrical with respect to the horizontal axis with respect to the convergence cup 29 at the electron beam emission end of the electron gun 28 and from the vertical axis about the tube axis. When it is arranged at a position of less than 45 ° and more than 30 °, the convergence cup 29 is located close to the deflection yoke 30, and the valve spacer 33 is disposed at the deflection yoke.
Even if it is arranged in the strong horizontal deflection magnetic field generated by 30, it suppresses a large eddy current flowing in the closed circuit formed by the valve spacer 33, the convergence cup 29, and the internal conductive film 26 caused by the strong horizontal deflection magnetic field. It is possible to reduce the damage of the neck caused by the temperature rise of the electrode at the electron beam emission end of the conventional electron gun and the gas emission from the electrode at the electron beam emission end of the electron gun.

In order to reduce the magnification of the electron gun and obtain good focusing characteristics, the electron gun is brought closer to the phosphor screen and the electrode at the electron beam emitting end of the electron gun is brought closer to the deflection yoke. Even if the horizontal deflection frequency is increased for higher performance, the temperature rise of the convergence cup is suppressed by suppressing the large eddy current flowing in the closed circuit formed by the valve spacer, the convergence cup and the internal conductive film. Can be suppressed.

Although the above embodiment has been described with respect to the color picture tube, the present invention can be applied to other cathode ray tubes.

[0029]

The valve spacers attached to the electrodes at the electron beam emitting end of the electron gun are four valve spacers arranged vertically symmetrical with respect to the horizontal axis orthogonal to the tube axis.
When these four valve spacers are arranged at positions at an equal angle of less than 45 ° from a vertical axis orthogonal to the tube axis with the tube axis as the center, these valve spacers, the electrode at the electron beam emission end of the electron gun, and the internal conductivity are arranged. The horizontal deflection field across the closed circuit formed by the membrane can be reduced. Thereby,
The eddy current flowing in the closed circuit can be reduced to suppress the temperature rise of the electrode at the electron beam emission end, and the neck damage and electron beam emission end of the electron gun caused by the temperature rise of the electrode at the electron beam emission end in the past. It is possible to reduce gas emission from the electrodes of the section.

[Brief description of drawings]

FIG. 1 (a) is a diagram showing a configuration of a color picture tube which is an embodiment of the present invention, and FIG. 1 (b) is a diagram showing an arrangement of valve spacers attached to a convergence cup thereof. ..

2 (a) and 2 (b) are views for explaining the action of a horizontal deflection magnetic field on a valve spacer attached to the convergence cup. FIG.

FIG. 3 is a diagram showing a main part configuration of a conventional color picture tube.

4 (a) and 4 (b) are diagrams for explaining the action of a horizontal deflection magnetic field on a valve spacer attached to a conventional convergence cup.

[Explanation of symbols]

 21 ... Funnel 25 ... Neck 26 ... Inner conductive film 28 ... Electron gun 29 ... Convergence cup 30 ... Deflection yoke 33 ... Valve spacer

Claims (1)

[Claims] 1. An inner surface of the neck is attached through an internal conductive film, which is attached to an electrode of an electron beam emitting end of an electron gun disposed in the neck of the envelope and is formed by coating on the inner surface of the neck. In a cathode ray tube having a plurality of valve spacers pressed against each other, the valve spacers are composed of four valve spacers arranged vertically symmetrical with respect to a horizontal axis orthogonal to the tube axis. A cathode ray tube, characterized in that it is mounted at an equiangular position of less than 45 ° from a vertical axis orthogonal to the tube axis with the axis as the center.