JPS6326916Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a cathode structure used in cathode ray tube electronics, and particularly improves the insulation between the cathodes and the first control electrode, or between the cathodes when a plurality of cathodes are arranged on the same plane. The present invention relates to improvements in cathode structures for

Figure 1 shows a cathode structure 1 commonly used in the past.
FIG. 3 is a partial cross-sectional view including the first control electrode showing 0;
The cathode cylinder 13, which is a cap-shaped cylinder with a thermionic emissive material layer deposited on the top, is caulked to an insulating stone 11 made of ceramic such as alumina or steatite.
The lower end portion is welded and fixed to the outer cathode support cylinder 12 which is fixed by caulking or the like at 12B. The insulating stone 11 that supported the cathode tube 13 is placed inside the first control electrode 14 which is a bottomed cylindrical shape with a through hole in the closed surface, and the upper surface position of the insulating stone 11 is regulated by a spacer 15, and the lower surface thereof is regulated by a spacer 15. The stator 16 is pressed into contact with the first control electrode 14, and the stator 16 is welded to the side surface of the first control electrode 14 to be supported and fixed. At this time, the height of the spacer 15 is the same as that of the cathode tube 13.
The distance between the top of the insulating stone 11 and the top surface of the insulating stone 11 is selected so that the difference in distance becomes a predetermined value.

Normally, a groove 11A surrounding the outer cathode support tube 12 is bored in the upper surface of the insulating stone 11 on the electron emitting surface side of the cathode tube 13. This is the cathode tube 1 during cathode ray tube operation.
The metal Ba that is reduced and produced from the electron emitting surface at the top of the cathode is evaporated by the heat of the heating wire inserted into the cathode cylinder 13 and the first control electrode even if this evaporated substance adheres to the upper surface 11B of the insulating stone 11. In order to prevent the insulation between the cathodes 14 and 14 from deteriorating, a blind spot is created within the angle from which the grooves 11A are viewed from the top of the cathode.

However, in the method of forming a blind spot for evaporated matter from the top of the cathode using the groove 11A described above, the deeper the groove 11A is, the more the groove 11A is required to improve the insulation between the cathode tube 13 and the first control electrode 14. The narrower the width, the better, but the thickness of the insulating stone 11 is usually about 1 to 2 mm, and if the width is made too deep, the mechanical strength of the insulating stone will be impaired. This makes it difficult to form the groove when forming the groove, making it impossible to obtain a necessary and sufficient blind spot. In particular, in cathode assemblies used in narrow electron guns for cathode ray tubes, the overall dimensions are reduced, and the annular groove 11A is formed in the insulating stone 11.
It is very difficult to process the extrusion die of the insulating stone 11 that forms the groove 11A, and it is also difficult to form the groove when pressing the insulating stone 11, resulting in poor accuracy and Due to the above restrictions, etc., there was a drawback that an effective blind spot could not be obtained.

The present invention eliminates the above-mentioned drawbacks and provides one or more cap-shaped cathode tubes fixed to one or more insulating stones by welding, respectively, the lower ends of one or more cap-shaped cathode tubes having a thermionic emissive material layer deposited on the top. In a cathode assembly equipped with an outer cathode support tube, the fixed portion of the outer cathode support tube on the upper surface of the insulating stone facing the top of the cathode tube has respective annular rings formed to surround each outer cathode support tube. To provide a cathode assembly for a cathode ray tube in which the upper part of an outer cathode support cylinder is fixed by inserting an elastic washer having an annular edge covering a groove except for a part of the outer side.

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

FIG. 2 shows a cathode structure 2 based on an embodiment of the present invention.
FIG. 3 shows a perspective view of an elastic washer with an annular edge, and for the sake of simplicity, the same parts as those in FIG. Add a sign. The upper caulked part of the outer cathode support cylinder 12 on the upper surface of the insulating stone 11 facing the top side of the cathode cylinder 13 is made up of an aperture 21B that fits into the outer diameter of the outer cathode support cylinder 12 and an annular edge 21A. An elastic washer 21 is inserted, and the outer cathode support tube 12 is caulked and fixed to the insulating stone 11 with caulked edges 12A and 12B as in the conventional case. The elastic washer 21 is made of a heat-resistant elastic material such as Inconel, and as shown in FIG. The outer diameter of the annular edge 21A is selected to be large enough to cover the outer side of the annular groove 11A formed on the upper surface 11B of the insulating stone 11 so as to surround the outer cathode support tube 12, leaving about 0.1 to 0.2 mm. It is. A cap-shaped cathode tube 13 whose top part is coated with a thermionic emissive material layer is welded and fixed to the outer cathode support tube 12 fixed to the insulating stone 11 at the lower end of the outer cathode support tube 12. The supported and fixed insulating stone 11 has its upper surface 11B positioned within the first control electrode 14 by a spacer 15, and its lower surface is supported and fixed to the first control electrode 14 by a stator 16.

According to the embodiment of the present invention, the annular groove 11A is for preventing insulation deterioration between the outer cathode support tube 12 and the first control electrode 14 due to deposition of evaporated matter from the top of the cathode tube 13.
Most of the groove is covered by the annular edge 21A of the elastic washer 21, so even if the width and depth of the annular groove 11A alone do not provide a sufficient blind spot against evaporative accretion, the annular edge 21A provides a perfect blind spot, and when forming the insulating stone 11, there is no need to make the groove deep and narrow at the expense of its strength and workability. Alternatively, even if there is little dimensional margin to form the necessary and sufficient annular groove 11A in the insulating stone 11, especially when the cathode assembly 20 is downsized, the annular groove 11A may be of insufficient size by applying the present application. Molding mold processing and manufacturing become extremely easy.

In addition, the metal Ba generated by reduction from the top of the cathode tube 13 during operation of the cathode ray tube not only accretes linearly onto the upper surface of the insulating stone 11, but also collides with residual gas molecules in the tube and scatters, and accretes vertically onto the upper surface of the insulating stone 11. However, this embodiment can form a sufficient blind spot and cover these problems.

Alternatively, as shown in another embodiment of the present invention shown in FIG. 4, in an in-line cathode assembly 30 in which three cathode cylinders 13 are arranged in-line in the same plane and fixed to an insulating stone 31, the central and both outer cathodes Support tube 12
In between, evaporated matter is deposited from the cathode tubes 13 on both sides, but the conventional annular groove 31A alone cannot provide a sufficient blind spot. However, in the embodiment, since the elastic washer 21 is inserted into the upper caulking part of each outer cathode support cylinder 12 and fixed by caulking, the first control electrode (not shown) in which the cathode structure 30 is housed is attached.
Not only the insulation between the two cathodes, but also the insulation between adjacent cathodes does not deteriorate.

Furthermore, since the elastic washer 21 made of metal is inserted into the upper caulking part of the outer cathode support tube 12 and caulked, the two fit together at the caulking edge 12A, and the elastic washer made of a heat-resistant elastic material presses against the caulking fixing part. Since the caulking is crimped, the strength of the crimping is dramatically improved, and the thermal aging effect that conventionally occurs when the outer cathode support cylinder 12 expands thermally during operation of the cathode ray tube and causes play in the crimped portion is prevented, resulting in an extremely stable cathode. characteristics are obtained. During operation of the cathode ray tube, the temperature at the top of the cathode tube 13 is approximately 700 to 800°C, and the temperature at the top of the cathode tube 13 is approximately 700 to 800 degrees Celsius, and the temperature at the top of the cathode tube 13 is approximately 700 to 800 degrees Celsius.
Although the temperature rises to about 500 to 600°C, since the elastic washer is made of a heat-resistant elastic material, it will not lose its elasticity even during thermal cycles during operation and non-operation. Furthermore, if the elastic washer 21 is made of a material with a coefficient of thermal expansion larger than that of the outer cathode support cylinder 12, the thermal expansion force of the elastic washer 21 is added during operation, and its caulking strength is further improved.

FIG. 5 is a perspective view showing another embodiment of the elastic washer 41, and inside the annular edge 41A is a chrysanthemum petal 41.
B is cut and raised alternately on the upper and lower surfaces of the annular edge 41A, and it is clear that the same effect as described above can be obtained even if this is used in the cathode structure described above.

[Brief explanation of the drawing]

FIG. 1 is a partial cross-sectional view including a first control electrode showing a conventionally used cathode structure; FIG. 2 is a cross-sectional view including a first control electrode showing a cathode structure according to an embodiment of the present invention; 5 is a perspective view showing an elastic washer according to one embodiment of the present invention, and FIG. 4 is a sectional view of an in-line cathode structure according to another embodiment of the present invention. 11, 31... Insulating stone, 11A, 31A... Annular groove, 12... Outer cathode support tube, 13... Cap-shaped cathode tube, 14... First control electrode, 15... Spacer,
16... Stator, 21, 41... Elastic washer.

Claims (1)

[Scope of utility model registration request] The cathode structure includes an outer cathode support tube fixed to an insulating stone to which the lower end of the cap-shaped cathode tube, the top of which is coated with a thermionic emissive material layer, is fixed by welding. At the fixed part of the outer cathode support tube,
An elastic washer made of a heat-resistant elastic material and having an annular edge that covers the annular groove on the upper surface of the insulating stone formed to surround the outer cathode support cylinder, leaving only a part of the outside thereof, is inserted, and the outer cathode A cathode assembly for a cathode ray tube, characterized in that the upper part of a support tube is fixed.