CN1160281A - Electron gun and cathode assembly for cathode ray tube and manufacturing method - Google Patents

Abstract

A method of manufacturing an electron gun for a cathode ray tube with a cathode and a plurality of grids, comprising the steps of: assembling first, second and third supports with insulating material; fixing the first grid at the second Align the first grid with the second support; fix the spacer on the second support, the spacer defines the distance between the first and second grid; make the first grid and the second grid aligning the third supports; and fixing the cathode on the third supports.

Description

Electron gun and cathode assembly for cathode ray tube and manufacturing method

The present invention relates to a method of manufacturing an electron gun and a cathode assembly of a cathode ray tube, in which a cathode, a spacer for a first grid and a second grid are assembled in one body in advance.

An example of a conventional electron gun for a cathode ray tube is outlined below with reference to FIG. 2. FIG. The electron gun shown in this figure is a single gun three-beam type (Trinitron type) electron gun matched with a color cathode ray tube, such as disclosed by Japanese Patent Publication Hei 5-166459. The electron gun includes three cathode assemblies 100 integrally fixing the cathode, the first grid and the spacer for the second grid. The electron gun also includes second to fifth grids G2-G5. Assemble the three cathode assemblies 100 with the second grid G2 through spacers in an inclined state, fix the second grid G2 and the third to fifth grids G3-G5 with each other with glass struts (bead glass) 101, and assemble It is a single-gun three-beam electron gun. The first and second grids G1 and G2 constitute a pre-focus system, and the third, fourth and fifth grids G3, G4 and G5 constitute a main lens system.

FIG. 3 shows an example of a cathode assembly 100 as disclosed, for example, in Japanese Patent Laid-Open No. 7-14508. The cathode assembly includes a first grid G1; a support 110 made of insulating material and fixing the first grid G1; and a cathode 111 disposed on the support 110 and opposite to the first grid G1. The first grid G1 is made of, for example, Kovar material, and the support member 110 is made of alumina ceramics. A spacer 112 is installed on a side of the support 110 on which the first grid G1 is installed. The second grid G2 is mounted on the upper surface 112a of the spacer 112 (see FIG. 2). The spacer 112 determines the distance between the first gate G1 and the second gate G2. The cathode 111 includes a cylindrical sleeve 120, a cathode cap 122 disposed on the front end of the sleeve 120, and an oxide 124 disposed on the top of the cathode cap 122 as an electron emission source. The cathode 111 of this configuration is inserted into the sleeve support 128 mounted on the lower surface of the support 110 . The heater 126 is placed inside the sleeve 120 .

A method of assembling the cathode assembly 100 is outlined below with reference to FIG. 4 . First, a soldering jig 140 is prepared, which has a first side 140b and a second side 140c. Several shafts 140a are placed on the first face 140b of the soldering jig 140 . A second surface 140c is formed outside the first surface 140b, which is in a state lower than the first surface 140b. The step between the first surface 140b and the second surface 140c is set to be equal to the distance d12 between the first grid G1 and the second grid G2. The first grid G1 and the spacer 112 are assembled on one side of the supporter 110 made of an insulating material, and a cathode (not shown) is placed on the other side of the supporter 110 . Specifically, the first grid G1 is placed on the first face 140b of the brazing jig 140, inserted on the shaft 140a of the brazing jig 140, and made of metal such as Fe-Ni alloy or Fe-Co-Ni alloy. The spacer 112 is disposed on the second face 140C of the jig 140 . Then, the support 110 is placed on the first grid G1 and the spacer 112 such that the plane 110 b of the support 110 is in contact with the first grid G1 and the spacer 112 . Furthermore, the plane 110b is metallized beforehand. The first grid G1 has an emission hole E at its center, and the supporting member 110 has a through hole 110a corresponding to the emission hole E (see FIG. 3 ). The supporting member 110 is pressed against the jig 140 side by the pressing member 140d, and in this state, the first grid G1 and the spacer 112 are fixed on the plane of the supporting member 110 by brazing. Thereby, opposite surfaces of the first grid G1 and the supporter 110 and opposite surfaces of the spacer 112 and the supporter 110 are brazed to each other.

In the existing assembly method, the first grid G1, the spacer 112 and the cathode support 128 are fixed to the support 110 made of ceramics or the like by brazing to assemble the cathode assembly; After measuring the distance between the first grid G1 and the cathode 111, the cathode sleeve 120 is inserted into the cathode assembly and welded together. The advantage of this method is that since the distance d1 between the first grid G1 and the second grid G2 is preset with a brazing jig before the cathode sleeve 120 is fixed on the cathode assembly, these can be assembled precisely. part. However, the disadvantage of this method is that since the brazing jig 140 must have high-precision dimensions and high heat resistance against thermal deformation, and it is necessary to manufacture supports made of ceramics or the like to fix these parts with high precision. 110, so the assembly cost is high. In order to overcome such disadvantages, another method has been proposed, which is to fix parts with glass, thereby reducing the assembly cost. However, this method has the following disadvantages: the accuracy of assembly is lower than that of brazing assembly, making the subsequent process difficult to operate.

The object of the present invention is to provide a method for manufacturing an electron gun of a cathode ray tube, which can reduce manufacturing cost and ensure assembly accuracy; the invention also provides a cathode assembly suitable for an electron gun.

In order to achieve the above object, according to a first aspect of the present invention, a method for manufacturing an electron gun of a cathode ray tube having a cathode and a plurality of grids is provided, which includes the following steps: The support is assembled as a whole; the first grid is fixed on the first support; the first grid is aligned with the second support; the spacer is fixed on the second support, and the spacer defines the first and second spacing between the two grids; aligning the first grid with the third support; and fixing the cathode on the third support. Preferably, the assembling step further includes a second support member consisting of a metal ring, a third support member consisting of a metal cylinder placed within the second support member, and a pair of metal rods placed inside the second support member. The first support and the third support are hermetically sealed to fix each other.

To achieve the above object, according to the second aspect of the present invention, a cathode assembly of an electron gun of a cathode ray tube having a cathode and a plurality of grids is provided, including a cathode for emitting electrons; The spacer of interval; The first supporting member of fixing first grid; The second supporting member of fixing spacer; And the third supporting member of fixed cathode; It is characterized in that the first, second and third supporting members are assembled as one. Preferably, the second support member constituted by a metal ring, the third support member constituted by a metal cylinder placed inside the second support member, and the second support member constituted by a pair of metal rods placed in the second and third support members The first support members in between are fixed to each other with an airtight seal.

According to the method described above, the base member is obtained by fixing the supporting member supporting the cathode, the supporting member supporting the first grid, and the supporting member supporting the spacer with an airtight seal; The components are precisely positioned on the base components, and they are fixed by welding; and the distance between the cathode and the first grid is precisely adjusted, and the cathode is fixed on the corresponding support by welding. The cathode assembly is assembled in the electron gun of the cathode ray tube. Therefore, this method is advantageous in precisely setting the distance between the cathode and the first grid and the distance between the first grid and the second grid.

Through the detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings, the above-mentioned and other objects, features and advantages of the present invention will be clear, wherein:

1A to 1D are schematic diagrams showing process steps in a method of manufacturing an electron gun for a cathode ray tube according to the present invention;

Fig. 2 is a block diagram showing an example of an electron gun of the related art for a cathode ray tube;

3 is a typical sectional view of a related art example of a cathode assembly of an electron gun for a cathode ray tube;

FIG. 4 is a typical view showing a manufacturing method of the cathode ray tube shown in FIG. 3. Referring to FIG.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

1A-1D are schematic diagrams showing the process steps of the manufacturing method of the cathode ray tube electron gun of the present invention. As shown in FIG. 1A, the first supporting member 1 for fixing the first grid, the second supporting member 2 for fixing the spacer to determine the distance between the first grid and the second grid are made with lower accuracy. The third supports 3 for fixing the cathodes are positioned relative to each other and are made integral with each other by insulating material 5, thus forming the base structure 4. Specifically, the second support member 2 constituted by a metal ring, the third support member 3 constituted by a metal cylinder placed inside the second support member 2, and the The first supporting member 1 placed between the second supporting member 2 and the third supporting member 3 is fixed together as a whole. Here, glass ceramics is used as the insulating material 5 . Please note that the present invention is not limited to the above constructions, and other alternative constructions that do not use hermetic welding can also be used. For example, it is possible to replace the insulating material 5 for hermetic sealing with ceramic parts, and to fix the supports to the insulating material 5 with glass. Compared with the method of using brazing method in the prior art to precisely position and fix the components relative to each other, the present invention is configured in such a way that only the support components are fixed with low precision by means of airtight sealing or the like. The support, forming the base member 4 .

Then, as shown in FIG. 1B , the first grid 6 is assembled on the pair of first supports 1 by welding or the like. The first grid 6 is formed in the shape of a cup capable of receiving the top of the third support, with an emission hole 7 in its center.

As shown in FIG. 1C , a pair of spacers 8 are installed on the second support 2 of the base member 4 so that the spacers 8 are precisely positioned with the first grid 6 pre-installed on the first support 1 . Here, before the pair of spacers 8 are welded on the second support 2, the distance between the upper surface 9 of the first grid 6 and the upper surface 10 of each spacer 8 is precisely set with a jig. In a subsequent step, a second grid will be mounted on the upper surface of the spacer 8 . The distance between the upper surface 9 of the first grid 6 and the upper surface 10 of each spacer 8 defines a distance d12 between the first and second grids. This distance d12 must be precisely controlled. The cathode assembly 11 in which the first grid and the spacer for the second grid are integrated is thus obtained.

As shown in FIG. 1D , the cathode 12 is mounted on the third support 3 of the base member 4 so that it is precisely aligned with the first grid 6 . The cathode 12 includes a cylindrical sleeve 13, a cathode cap 14 placed on the front end of the sleeve 13, and an oxide 15 disposed on the top of the cathode cap as an electron emission source. The sleeve 13 is inserted into the third support 3 . The cylindrical sleeve 13 has a bottom with a diameter slightly larger than the front end. The sleeve 13 is temporarily fitted in the third support member 3 by the frictional contact between the outer peripheral surface of the sleeve 13 and the inner peripheral surface of the third support member 3 . Thereafter, the distance d01 between the oxide 15 and the first grid 6 is measured with a pneumatic micrometer or the like, and adjusted appropriately. In addition, the measurement of the distance d01 with a micrometer can be accomplished by feeding air into the oxide 15 under pressure through the emission hole 7 formed in the first grid 6, and measuring the return pressure from the oxide 15. After accurately adjusting the distance between the oxide 15 and the first grid 6 , the sleeve 13 is welded on the third support member 3 .

The finally assembled cathode assembly 11 is mounted on the second grid through the spacer 8 . Thereafter, as shown in FIG. 2, the second grid G2, the third grid G3, the fourth grid G5, the fifth grid G5, etc. are fixed by the rods, and the electron gun of the cathode ray tube is assembled.

As described above, according to the present invention, the first supporting member for fixing the first grid, the second supporting member for fixing the spacer for defining the space between the first and second grids, and the third supporting member for fixing the cathode the supports are positioned relative to each other with relatively low precision and are integrated with hermetic sealing, thus forming the base member; and the corresponding supports for assembling the first grid, the spacer, and the cathode to the base member with high precision superior. Therefore, the distance d12 between the first gate and the second gate can be easily and precisely set with the spacer. Since supports made of metal and having various shapes can be easily fixed together by airtight sealing or the like, the present invention is advantageous in terms of manufacturing cost. In addition, to provide electron guns having different first grid emission hole diameters and d12 values, it can be easily produced only by changing the first grid member and the spacer assembling jig.

Although preferred embodiments of the invention have been described in specific forms, such description is for the purpose of illustration only, and it will be understood that improvements and modifications may be made to the invention without departing from the spirit and scope of the appended claims.

Claims (4)

1. A method for manufacturing an electron gun of a cathode ray tube with a cathode and a plurality of grids, comprising the following steps: Assembling the first, second and third support members as a whole with an insulating material; fixing the first grid on a first support; aligning the first grid with the second support; fixing a spacer on the second support, the spacer defining a spacing between the first and second grids; aligning the first grid with the third support; and Fix the cathode on the third support. 2. The method of claim 1, wherein the assembling step comprises: A second support made of a metal ring, a third support made of a metal cylinder placed inside the second support, and a pair of metal rods made of a pair of metal rods placed between the second and The first supports between the third supports are fixed to each other. 3. A cathode assembly for an electron gun of a cathode ray tube having a cathode and a plurality of grids, comprising: a cathode that emits electrons; a spacer defining a spacing between the first gate and the second gate; fixing the first support member of the first grid; a second support for securing the spacer; and a third support for fixing the cathode; Wherein the first, second and third supports are assembled into one body. 4. The cathode assembly according to claim 3, wherein the second support member constituted by a metal ring, the third support member constituted by a metal cylinder and placed within the second support member, are hermetically sealed, and the first support member, which is formed by a pair of metal rods and placed between the second and third support members, are fixed to each other.

Images