JPH01200533A - Manufacture of electron gun cathode - Google Patents

Abstract

PURPOSE:To spray a metal oxide to a coil in a non-dense condition and obtain a small electron gun by pressing and fixing one end of both end parts of a directly heated type cathode coil densely wound to the upper surface of one of a cathode support pin pair, and pressing and fixing the other end to the upper surface of another cathode support pin with the coil tensioned and the winding thereof kept in a non-dense condition. CONSTITUTION:In the manufacture of an electron gun cathode used for a small cathode-ray tue, one end 9 of a coil 5 densely wound is pinched with forceps and the like, a part immediately near the winding start of the coil 5 is set to the upper surface of a cathode support pin 8 and a part near the inner side of the pin 8 is pressed and fixed, using a crimp style terminal 10. Furthermore, a part near the outside of the pin 8 is pressed and fixed, and the remnant of the unnecessary end 9 is separated with the terminal 10 pressed. Then, while the coil 5 is being elongated, a part immediately near the winding end of the coil 5 is set to the upper surface of another pin 3, and pressed and fixed near the inner side of the pin 8' via the terminal 10. Finally, the coil 5 after pressed and fixed is set to an electron emission substance spray tool and an electron emission substance 6 is sprayed to a part corresponding to the coil.

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a method for manufacturing an electron gun cathode used in a small cathode ray tube.

[Conventional technology]

As video cameras become more widespread, demand for small cathode ray tubes used as viewfinders is increasing. There is also a desire to take pictures immediately when needed for mobile use, and a cathode ray tube that is small, quick-response, and low-power consumption is desired. As the cathode of the electron gun used in such a cathode ray tube, a directly heated cathode in which a heater wire is wound into a coil is used. The heater wire is formed into a coil by winding it around a suitable core wire, shaping it by heat treatment, and then removing the core wire by chemical treatment. FIG. 3 is a schematic diagram for explaining coil manufacturing. Spool (1) as shown in figure A
Pull out the core wire (2 wire (e.g. molybdenum wire)) wound around the spool (3), and pull out and wrap the heater wire (4) (e.g. tungsten wire) wound around the spool (3) around the outer periphery of the core wire. (5) is wrapped tightly,
The space between the coil parts (5) is loosely wound. Figure B
is an enlarged view of the rolled up part. A heater wire with a wire diameter of 5.8 μm is wound around a core wire with a wire diameter of 50 μm, and the coil pitch is about 10 μm and the coils are tightly wound. After that, it is shaped, the core wire is removed by chemical treatment, and metal oxide, which is an electron emitting substance, is applied in a cylindrical shape. FIG. 4 is a cross-sectional view of a coil coated with an electron emitting material according to the prior art. FIG. 5 is an external view of the coil fixed to the cathode support pin. The electron emitting material (6) is deposited in a cylindrical shape on the coil (4) by an electrodeposition method or a spraying method. As shown in FIG. 5, both ends of this coil are fixed onto a pair of cathode support pins (8), (8°) set up on, for example, a ceramic insulating support (7). At this time, since the coil (5) is coated with the electron emitting material (6), both ends of the coil are not stretched, and the cathode support pin (8) is attached to the coil (5).
) and (8'). [Problems to be solved by the invention] The technique of depositing electron emitting material in a cylindrical shape on a tightly wound heater wire coil is difficult, and materials deposited by electrodeposition tend to crack when heated. , the resolution of the cathode ray tube decreases. In addition, in the spraying method, since the coil is dense, it is difficult to fill the electron emitting material into the coil, and the electron emitting material can only be deposited on the surface. If the surface layer is too thick, the adhesion strength will be weak and the electron emitting material will fall off due to vibration.
If it is thin, the absolute amount of electron-emitting material will be small, which has the disadvantage of shortening the life of the cathode. Also, as shown in Figure 5, since the coil (5) is located in the center of the cathode support pin and the heater wire is thin, the coil (5) may be damaged by shock or vibration.
) vibrates, causing the image of the cathode ray tube to fluctuate, making it inconvenient for use as a cathode ray tube for the viewfinder of a video camera intended for portable use. Also, the ends (9), (9') of the heater wire protrude after the coil is crimped, and when the electron gun is completed as shown in Figure 6, the ends (9), (9') of the heater wire protrude. There were some cases in which the wire came into contact with the first grid, resulting in poor conduction. FIG. 6 is a sectional view of the electron gun, in which G1 is the first grid, which is the control grid, and G2 is the second grid, which is the acceleration grid. [Means for Solving the Problems] In order to solve the above-mentioned drawbacks, the present invention has provided that one end of both ends of a tightly wound directly heated cathode coil is connected to the two sides of one of a pair of cathode support pins. , pull the directly heated cathode coil, make the winding state loose, and then press the other end to the top surface of the other cathode support pin. Now sprays metal oxide. The coil was crimped the first time on the inside of the pair of opposing cathode support pins, and the second time was crimped on the outside to separate the rest of the coil. [Embodiment] FIG. 1 is a schematic diagram for explaining an embodiment of the present invention. A-C in the same figure is a partial cross-sectional view for explaining the process of crimping the coil to the cathode support pin, and the same figure is a partial cross-sectional view for explaining the method of spraying the electron emitting material onto the coil. Figure E is an external view after spraying has been completed, and Figure F is a sectional view of the coil coated with electron emitting material. Part 1 below
DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the figures. First, as shown in Figure A, pinch one end (9) of the tightly wound coil (5) with tweezers or the like (not shown), and then insert the cathode support pin (8) at the end closest to the beginning of the winding of the coil (5). , and crimp the inside of the cathode support pin (8) with the crimp terminal (lO). Next, press the outer side as shown in Figure B. While pressing the crimp terminal (10), use tweezers or the like to cut off the remainder of the unnecessary end (9). Next, as shown in Figure 0, hold the other end (9') with tweezers or the like, and while pulling and stretching the coil (5), insert the part closest to the end of the coil (5) onto the other cathode support pin (8'). ) and crimp the inside of the cathode support pin (8') using the crimp terminal (10). Furthermore, as in Figure B, the outer side is crimped and the remainder of the end (9') is cut off. After the crimping is completed, set it in a jig for spraying electron emitting material as shown in Figure D. In the figure, (12) is a shielding member to prevent electron emitting material from adhering to unnecessary parts, and (11) is a part corresponding to the coil so that electron emitting material does not adhere to the coil. This is a shielding member with a hole (13) provided in it. As shown by the arrow, the electron emitting material is deposited on the coil by spraying it from above. According to this embodiment, the electron emitting material is deposited in the shape of a mountain with a high center in the longitudinal direction of the coil. Figure E is its external view. Also, Figure F is a cross-sectional view of a coil coated with an electron emitting material, but since the coil is in a sparse state, the electron emitting material easily enters the coil from between the wires of the coil and is densely packed. ing. In this example, the interval between the lIa pole support pins is 1200 μm.
, the diameter of the heater wire is 5.8 μm, the number of turns is 60,
The distance between the heater wires is approximately 14 μm. The particle size of the electron emitting material is 2 to 3 μm, but since it is sprayed in the form of a paste, condensation occurs, and if the coil is tightly wound, it will not enter the coil. FIG. 2 is a cross-sectional view of an electron gun incorporating an electron gun cathode manufactured according to the present invention. The center part of the coil that emits electrons is sufficiently coated with electron emitting material, and the emitted electrons are transferred to the first grid (Gl) and the second grid (G3).
There is no remaining part of the crimped end of the coil that pops out from the hole drilled in the center of the coil in the direction of the upper part (not shown, but toward the phosphor screen), so there is a risk of it coming into contact with the first grid. There isn't. [Effects of the Invention] According to the present invention, since the coil is crimped to the cathode support pin in a stretched state, (1) the coil is loosely wound, so the electron emitting substance fills into the inside of the coil; This makes it possible to produce cathodes with long lifetimes. (2) The coil is tightly wound and crimped, then pulled and crimped during crimping, so the coil is under tension due to the tension, making it difficult for the coil to vibrate even when subjected to shock or vibration. , it was possible to prevent image fluctuation. (3) After crimping, the remaining part of the coil is separated while the crimping terminal is pressed, so the remaining part can be separated while being sufficiently crimped, and the crimping strength does not deteriorate. (4) Since there is no remaining part of the coil, it is no longer possible to contact the first grid and cause a conduction failure. As explained above, according to the present invention, a high-quality compact cathode ray electron gun with a long life can be manufactured, and the present invention is useful from an industrial standpoint.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram for explaining one embodiment of the present invention.
D is a partial cross-sectional view for explaining the method of spraying electron emitting material onto the coil, E is an external view after spraying is completed, and F is a cross-sectional view of the coil coated with electron emitting material. . FIG. 2 is a sectional view of an electron gun according to the present invention. FIG. 3A is a schematic diagram for explaining the manufacturing of the coil, and FIG. 3B is an enlarged view of the rolled up portion. FIG. 4 is a cross-sectional view of a coil coated with an electron emitting material according to the prior art, FIG. 5 is an external view of the coil fixed to a cathode support pin, and FIG. 6 is a cross-sectional view of the electron gun. (4) Heater wire (5) Coil (6) Electron emitting material (8), (8') Cathode support pin (9), (9') Coil end (10) Crimp terminal 12 Figure 6 Figure 3

Claims (2)

[Claims] (1) One end of the tightly wound directly heated cathode coil is crimped onto the upper surface of one of a pair of cathode support pins, and the directly heated cathode coil is pulled to loosen the winding state. and crimping the other end to the upper surface of another cathode support pin, and spraying metal oxide, which is an electron emitting substance, onto the sparse coil. (2) A first crimping process is performed on the inside of the pair of opposing cathode support pins, and a second crimping process is performed on the outside of the pair of opposing cathode support pins to separate the remainder of the coil. Method for manufacturing an electron gun cathode.