JP2000243313A - Cathode-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve an impact resistant characteristic of a cathode-ray tube without incurring the degradation of a withstand voltage characteristic, a neck crack and the deterioration of productivity. SOLUTION: In a cathode-ray tube where the electron beam emitting end side of an electron gun 27 is fixed to this electron beam emitting end side electrode C to be supported by plural elastic supports 34 brought into pressure contact with a neck inside surface via a conductive film 33 formed on the inside surface of a neck 25, and the central axis of the electron gun on the electron beam emitting end side coincideds with the central axis of the neck by support of these elastic supports, a projecting part 36 projecting in the neck inside surface direction is formed in the electron beam emitting end side electrode.

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 such as a color cathode ray tube and, more particularly, to a cathode ray tube having improved support of an electron gun on an electron beam emitting end side.

[0002]

2. Description of the Related Art Generally, a color cathode ray tube has an envelope composed of a panel and a funnel-shaped funnel, and a phosphor screen composed of a three-color phosphor layer is provided on the inner surface of the panel. Then, a shadow mask is arranged on the inside. On the other hand, an electron gun that emits three electron beams is arranged in the cylindrical neck of the funnel. Then, the three electron beams emitted from the electron gun are deflected by the horizontal and vertical deflection magnetic fields generated by the deflection yoke mounted outside the funnel, and the phosphor screen is horizontally and vertically scanned through a shadow mask. , And a structure for displaying a color image.

As such a color cathode ray tube, an in-line type color cathode ray tube in which an electron gun emits three electron beams arranged in a row is widely used at present.

As shown in FIG. 4, the electron gun is provided with three cathodes K, three heaters (not shown) for heating these cathodes K, and the cathode K in order from the cathode K toward the phosphor screen. A plurality of electrodes G1 to G6 (six electrodes in the illustrated example) and a shield cup C attached to the phosphor screen side end of the sixth electrode G6;
These heater, cathode K and a plurality of electrodes G1 to G
6 is formed in a structure fixed by a pair of insulating support rods 1. The shield cup C is formed in a cup shape having an opening on the phosphor screen side as shown in FIG.

In this electron gun, the cathode K side is supported by a stem pin 4 provided on a stem 3 for sealing the end of the neck 2, the electron beam emitting end side is attached to a shield cup C, and the funnel has a large diameter. It is supported by a plurality of elastic supports 7 that are in pressure contact with the inner surface of the neck 2 via a conductive film 6 applied and formed from the inner surface to the inner surface of the neck 2. Thereby, the electron gun is connected so that the central axis of the electron gun coincides with the central axis of the neck 2 (coincident with the tube axis Z).

[0006] As shown in FIG.
At one end, a fixing portion 9 welded to the shield cup is formed by bending, and at the other end, a contact portion 10 having a convex curved surface is formed by pressing the inner surface of the neck through a conductive film. It is formed in a strip shape with a leaf spring portion 11 interposed between it and the contact portion 10.

[0007]

As described above, in the electron gun of the color cathode ray tube, the cathode side is supported by the stem pin provided on the stem for sealing the neck end, and the electron beam emitting end is located at the electron beam emitting end. Mounted on the side electrode (shield cup) and supported by a plurality of elastic supports pressed against the inner surface of the neck via the conductive film, whereby the center axis of the electron gun is supported so as to coincide with the center axis of the neck. ing.

The elastic support body has a fixed portion welded to the electrode on the electron beam emitting end side formed at one end by bending, and a surface pressed against the inner surface of the neck via a conductive film at the other end has a convex curved surface. The contact portion is formed, and is formed in a strip shape with a leaf spring portion interposed between the fixed portion and the contact portion.

However, if the electron beam emitting end side is supported by the elastic support, after the convergence adjustment, the position of the electron gun is shifted due to an external impact applied during transportation or the like, and the convergence characteristics and landing characteristics may be deteriorated.

That is, generally, a color cathode ray tube has 3
By adjusting the mounting angle of the deflection yoke so that the electron beam passes through a predetermined position of the deflection magnetic field generated by the deflection yoke, adjustment is performed so that optimum convergence is obtained over the entire surface of the phosphor screen. Therefore, in order to display a good image, it is necessary to immediately return to the original position even if the electron gun is displaced due to an external impact. However, the conventional elastic support has a problem in that the spring strength is not sufficient against the above-mentioned external impact, and when a large external impact is applied, the elastic support does not return to its original position, and the convergence characteristics and the landing characteristics are significantly deteriorated. .

In order to prevent such deterioration in characteristics, the spring strength of the elastic support may be increased to increase the support strength of the electron gun. However, if the spring strength of the elastic support is increased, the color cathode ray tube manufacturing process may be increased. When the electron gun is inserted into the neck and sealed, the conductive film on the inner surface of the neck is shaved due to friction with the contact portion of the elastic support, and the scraps of the shaved conductive film adhere to the electron gun or its vicinity. As a result, a discharge in the tube, a leak between the electrodes, etc. occur to deteriorate not only the withstand voltage characteristic but also damage the inner surface of the neck and cause a neck crack.

As a means for solving such a problem, there is a method of mounting a large number (6 to 8 or more) of elastic supports having relatively low spring strength. According to this means,
A supporting strength equivalent to that of using the elastic support having high spring strength is obtained. In addition, it is possible to prevent the conductive film from being scraped, thereby preventing deterioration of withstand voltage characteristics such as discharge in a tube and leakage between electrodes, and neck cracks caused by damage to the inner surface of the neck. However, such means has a problem in that the number of parts increases, the mounting time increases, and the productivity decreases.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is an object of the present invention to improve the impact resistance of a cathode ray tube without deteriorating withstand voltage characteristics, neck cracks, and lowering productivity. Aim.

[0014]

An electron gun having a plurality of electrodes is provided in a neck of a funnel, and an electron beam emitting end side of the electron gun is fixed to the electrode on the electron beam emitting end side and is provided on an inner surface of the neck. It is supported by a plurality of elastic supports pressed against the inner surface of the neck via the formed conductive film, and the center axis of the electron gun at the electron beam emission end side coincides with the center axis of the neck by the support of the elastic supports. In the cathode ray tube, a protruding portion protruding toward the inner surface of the neck was formed on the electrode on the electron beam emitting end side.

When the electron beam emitting end is eccentric due to an external impact, the projecting portion of the electrode on the electron beam emitting end is formed between the fixed portion of the elastic support on the eccentric side with the electrode and the press contact portion with the inner surface of the neck. It was configured to contact between.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a color cathode ray tube which is one embodiment of the present invention. This color cathode ray tube has an envelope composed of a panel 20 and a funnel 21 having a funnel shape.
A phosphor screen 22 made of a three-color phosphor layer that emits blue, green, and red light is provided on the inner surface of 0, and a shadow mask 23 is disposed inside the phosphor screen 22 so as to face the phosphor screen 22. On the other hand, in a cylindrical neck 25 of the funnel 21, three electron beams 2 arranged in a line passing on the same horizontal plane
An electron gun 27 for emitting 6B, 26G, 26R is connected. The three electron beams 26B, 26G, and 26R emitted from the electron gun 27 are deflected by horizontal and vertical deflection magnetic fields generated by a deflection yoke 29 mounted outside the funnel 21, and the phosphors are passed through a shadow mask 23. The screen 22 is formed to display a color image by scanning the screen 22 horizontally and vertically.

The electron gun 27 has three cathodes K arranged in a row in the horizontal direction, three heaters (not shown) for heating these cathodes K, and a plurality of cathodes K arranged in the direction of the phosphor screen in order from the cathode K. The plurality of electrodes G1 to
G6 (six in the illustrated example) and a shield cup C attached to the end of the sixth electrode G6 on the phosphor screen side, the heater, the cathode K and the plurality of electrodes G1.
G6 are formed in a structure fixed by a pair of insulating support rods 1.

In the electron gun 27, the cathode K side is supported by a stem pin 32 provided on a stem 31 for sealing the end of the neck 25, the electron beam emission end side is attached to the side surface of the shield cup C, and the funnel It is supported by a plurality of elastic supports 34 which press against the inner surface of the neck 25 via a conductive film 33 formed by coating from the inner surface of the large diameter portion to the inner surface of the neck 25. Thereby the electron gun 27
Are arranged so that the central axis of the central axis (5) coincides with the central axis of the neck 25 (coincident with the tube axis Z).

The elastic support 34 has, similarly to the elastic support shown in FIG. 6, a fixed portion 9 which is welded to a side surface of the shield cup formed at one end and a conductive film formed at the other end via a conductive film. Contact part 1 in which the surface pressed against the inner surface of the neck is a convex curved surface
It is formed in a strip shape in which a leaf spring portion 11 is interposed between the fixed portion and the contact portion 10.

In particular, in this embodiment, as shown in FIG. 2, the shield cup C is attached to the sixth electrode all around the opening edge on the phosphor screen side and disposed in the neck. A flange-shaped annular projection 36 is formed to project in the inner surface direction of the neck. The protruding length of the protruding portion 36 in the direction of the inner surface of the neck is such that the protruding portion 36 is arranged so that the central axis of the electron gun coincides with the central axis of the neck, so that the protruding portion 36 does not contact the elastic support member and is as close as possible. Is formed.

When the projection 36 protruding in the neck inner surface direction is provided on the shield cup C constituting the electron beam emitting end of the electron gun 27 as described above, the conductive film 33 is cut when the electron gun 27 is sealed. It can be inserted into the neck 25 without any damage and without damaging the inner surface of the neck 25. Therefore, it is possible to prevent deterioration of withstand voltage characteristics such as discharge in a tube and leakage between electrodes. In addition, even if the electron gun is displaced due to an external impact, the color CRT can be immediately returned to the original position and the convergence characteristics and the landing characteristics are not deteriorated.

That is, the spring constant k of a leaf spring is generally
The length of the leaf spring is 1, the width is b, the thickness is h, and the longitudinal elastic modulus is E.
Then, k = b × h ³ × E / 4 × l ³ . Therefore, when the length 1 is shortened, the spring constant of the leaf spring increases, and the leaf spring becomes a spring having relatively high spring strength. Conversely, when the length 1 is increased, the spring constant k decreases, and the spring has a relatively low spring strength.

Therefore, with the configuration as in this embodiment, as shown in FIG. 3A, the contact portion 10 extends from the boundary 38 between the fixed portion 9 acting as a leaf spring and the leaf spring portion 11.
The length l1 to the contact point 39 with the conductive film 33 can be made sufficiently long to reduce the spring strength. When the electron gun is sealed, the inner surface of the neck 25 can be formed without shaving the conductive film 33. It can be inserted into the neck 25 without damage. Therefore, it is possible to prevent deterioration of withstand voltage characteristics such as discharge in a tube and leakage between electrodes caused by the scraps of the conductive film shaved off and attached to the electron gun or its vicinity.

Further, when the electron beam emitting end side of the electron gun is eccentric due to an external impact, as shown in FIG.
The leaf spring portion 11 of the elastic support 34 attached in the eccentric direction contacts the protrusion 36 of the shield cup C. In this case, the portion acting as a leaf spring has a length l2 from the contact point 40 with the protrusion 36 to the contact point 39 with the conductive film 33 of the contact portion 10, and the spring strength is increased. Moreover, the difference in spring strength between the elastic support 34 attached in the eccentric direction and the elastic support 34 on the opposite side increases. Therefore,
Due to the high spring strength and the difference in spring strength between the elastic support 34 on the opposite side, the eccentric electron beam emitting end can be quickly and correctly returned to the original position.

In the above embodiment, the projecting portion is formed at the open end of the shield cup. However, the same effect can be obtained by forming an annular projecting portion at the intermediate portion of the side wall of the shield cup.

In the above embodiment, the protrusion is formed in a ring shape. However, the protrusion may be formed at least at a portion of the elastic support member facing the spring portion, and is not necessarily formed in a ring shape. Absent.

Although the above embodiment has been described with reference to a color cathode ray tube, the present invention can be applied to a cathode ray tube other than the color cathode ray tube.

[0029]

As described above, when the electrode on the electron beam emitting end side of the electron gun is provided with a protruding portion projecting toward the inner surface of the neck, the conductive film on the inner surface of the neck is sealed by the elastic support when the electron gun is sealed. Can be inserted into the neck without shaving the inner surface of the neck and without damaging the inner surface of the neck, thereby preventing deterioration of withstand voltage characteristics such as discharge in a tube and leakage between electrodes. In addition, even if the electron gun is displaced due to an external impact, the cathode ray tube can be immediately returned to the original position, and the convergence characteristics and the landing characteristics are not deteriorated.

[Brief description of the drawings]

FIG. 1A is a diagram showing a configuration of a color CRT according to an embodiment of the present invention, and FIG. 1B is a diagram showing an arrangement of an electron gun in a neck.

FIG. 2 is a view showing a structure of a shield cup on an electron beam emitting end side of the electron gun.

FIGS. 3A and 3B are diagrams for explaining the action of a shield cup on an elastic support for supporting the electron beam emitting end side of the electron gun. FIG.

FIG. 4 is a view showing an arrangement of a conventional color cathode ray tube in a neck of an electron gun.

FIG. 5 is a view showing a structure of a shield cup of a conventional color CRT electron gun.

FIG. 6 is a view showing the structure of a conventional elastic support for supporting an electron beam emitting end side of an electron gun of a color cathode ray tube.

[Explanation of symbols]

 21 Funnel 25 Neck 27 Electron Gun 33 Conductive Film 34 Elastic Support 36 Projection C Shield Cup

Claims (2)

[Claims] An electron gun having a plurality of electrodes is provided in a neck of a funnel, and an electron beam emitting end of the electron gun is fixed to an electrode on the electron beam emitting end and formed on the inner surface of the neck. It is supported by a plurality of elastic supports that are in pressure contact with the inner surface of the neck via a conductive film, and the central axis of the electron gun at the electron beam emitting end side coincides with the central axis of the neck due to the support of the elastic supports. A cathode ray tube, wherein a projection protruding toward the inner surface of the neck is formed on the electrode on the electron beam emitting end side. 2. When the electron beam emitting end side is eccentric due to an external impact, the projecting portion of the electrode on the electron beam emitting end side is fixed to the electrode of the elastic support member on the eccentric side, and is pressed against the inner surface of the neck. 2. The cathode ray tube according to claim 1, wherein the cathode ray tube is in contact with the cathode ray tube.