JP2685467B2 - Electron gun electrode assembly for color picture tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention provides a color image receiving method capable of welding and joining a plurality of components at a flange facing portion by a laser welding method without damaging an assembly jig by laser irradiation. The present invention relates to an electron gun electrode assembly for a tube. [Prior Art] Electron gun electrode assembly for color picture tube
Since the image quality of the image receiving screen is greatly affected, it is necessary to improve the assembly accuracy of the electron gun electrode assembly in order to obtain a color picture tube of good image quality. FIG. 2 shows an example of a conventional bipotential focusing type in-line type electron gun. FIG. 2A is a sectional view taken along a plane where three electron beams exist in parallel, and FIG. 2B is orthogonal to the plane. It is sectional drawing by a plane. 1A, 1B, 1C in the figure
Is a cathode that emits electron beams A, B, and C from the top surface, 2 is a control electrode that controls the electron beams A to C, 3 is an accelerating electrode that accelerates the electron beams A to C, and 4 is an electron beam A to C Is a focusing electrode for focusing the lower focusing electrode 5 and the upper focusing electrode 6 which are joined together in advance. Reference numeral 7 is an anode, and 8 is a convergence electrode. The control electrode 2, the acceleration electrode 3, and the lower focusing electrode 5 are provided with electron beam passage holes 2A to 2C, 3A to 3C, and 5A to 5C, respectively, and face the bottom surfaces of the upper focusing electrode 6 and the anode 7, respectively. Together with the three throttle holes 6A-6C and 7A-7C
Three main lenses corresponding to the three electron beams A to C are formed. The operating voltage of the electron gun is, for example, 0 V applied to the control electrode 2, 700 V applied to the acceleration electrode 3, about 7 kV applied to the focusing electrode 4, and 25 kV applied to the anode 7. In the electron gun constructed in this way, three cathodes 1A
The three electron beams A to C, whose electron beam amounts are controlled by the signal potentials given to 1C to 1C, are slightly separated by the prefocus lens formed between the opposing holes of the acceleration electrode 3 and the lower focusing electrode 5. After receiving the focusing action, the upper focusing electrode 6
The respective main lenses formed by the anode and the anode 7 are focused so as to form an image on the fluorescent surface of a picture tube (not shown). At the same time, the electron beams A and C on both sides pass through the electron beam passage holes 7A and 7C of the anode 7 and the electron beam passage hole 6 of the upper focusing electrode 6, respectively.
The electron beam A, B, C is provided with an inclination of an angle θ by a known means for slightly eccentricity to A, 6C.
Concentrate on one point. FIG. 3 (a) is a top view of the focusing electrode 4 taken along the line PP 'shown in FIG. 2 (a). The electrodes 2 to 7 of the electron gun are insulated and supported by the multi-form glass 9 shown in FIG. 3 (a) and arranged in a cylindrical neck tube (not shown). The cylindrical portion 6a of 6 is an ellipse having a major axis in the arrangement direction of the three electron beam passage holes 6A to 6C, and the joint portion of the flange 6b is inserted into and supported by the multi-form glass 9. The lower focusing electrode 5 is similarly formed. The focusing electrode 4 includes a lower focusing electrode 5 and an upper focusing electrode 6.
Are preliminarily combined and joined by an assembly jig as shown in the central sectional view in the minor axis direction shown in FIG. 3 (b). As can be seen from this figure, at least two cores 11 (which appear as one overlapping in this figure) set up on the jig substrate 10,
Holes 6A, 6B, 6C of the upper focusing electrode 6 and holes 5 of the lower focusing electrode 5
A, 5B, 5C (6A, 6C and 5A, 5C are not shown) are fitted together, the above focusing electrodes are sandwiched between the substrate 10 and the substrate 12, and the plural places of the flanges 6b and 5b pressed against each other are placed. The focus welding electrode 4 is assembled by joining at the resistance welding point 13. Each of the lower focusing electrode 5 and the upper focusing electrode 6 has a thickness of about 0.3 m.
The stainless steel sheet of m is produced by press drawing, but the relative error of the parallelism between the upper and lower surfaces becomes larger in the minor axis direction of the tubular portions 5a and 6a than in the major axis direction. Therefore, in the assembling method shown in FIG. 3 (b), the parallelism error between the lower focusing electrode 5 and the upper focusing electrode 6 remains in the focusing electrode 4 as shown in FIG. 2 (b). The bottom surface of the lower focusing electrode 5 is inclined. The in-line color picture tube uses a static convergence method in which the magnetic field distribution of a deflection coil (not shown) is pincushion-shaped in the horizontal direction and barrel-shaped in the vertical direction to concentrate three electron beams over the entire fluorescent surface. When the bottom surface of the lower focusing electrode 5 is inclined as shown in FIG. 5, the electron beam B emitted from the cathode 1B has a difference in image resolution, that is, focusing characteristics, above and below the fluorescent surface, as is well known. The image quality was degraded. As a measure against such a problem, for example, Japanese Patent Application Laid-Open No. 60-163335 discloses a method of joining and assembling upper and lower focusing electrodes as shown in FIGS. In FIG. 4, the focusing electrode 40 is composed of a lower focusing electrode 50 and an upper focusing electrode 60 as in the conventional case, and the central electron beam passage holes 50B and 60B are shown in the figure.
At least two cored bars 71 are provided on the lower substrate 70 so as to be vertically movable by springs 72. The upper board 73 has multiple pins
The spring 74 is arranged so as to be vertically movable. A plurality of spacers 76 are arranged between the lower and upper substrates 70, 73, and these spacers 76 are set to be slightly longer than the sum of the lengths of the electrodes 50, 60. It should be noted that, at the location where the pin 74 presses the flange 60b of the upper focusing electrode downward, the protrusion of the flange 50b of the lower focusing electrode is made small so as to avoid the pin 74. The lower focusing electrode 50 and the upper focusing electrode 60 have holes 50A to 5 respectively.
Fit 0C, 60A to 60C to the core metal 71, and place the upper substrate 73 on the spacer 7
Press it closely to 6. While being held in this way, laser light is emitted from the direction of the arrow to weld the flanges 50b and 60b at a plurality of positions from the side surface to join them. Since welding with laser light does not require mechanical stress, it is possible to assemble parts with high precision while maintaining parallelism at the time of setting and coaxiality of holes. FIG. 5 shows the focusing electrode 40 assembled by such a method, and in the figure, 78 are a plurality of welding points by laser light. FIG. 6 is a sectional view of a main part of a laser welding part. Thus, when the focusing electrode 40 with improved accuracy of parallelism and coaxiality of the upper and lower surfaces is used in the electron gun, an excellent color picture tube having good and uniform focusing performance over the entire fluorescent surface can be obtained. . However, in the case of such a structure, as can be seen from FIG. 6, during laser welding, the laser light passes through the gap (0.05 to 0.5 mm) between the flanges 50b and 60b and directly irradiates the cored bar 71. As a result, the cored bar 71 is locally melted, and splash is attached to the periphery of the cored bar 71.
There were problems such as the 40 being stuck in the core 71 and the life of the assembly jig being extremely short. [Problems to be Solved by the Invention] The present invention solves the problems that occur when assembling the above-described conventional multi-component electrodes into a single electrode assembly by laser-welding the flange portion of the husband, etc. The assembly jig is not damaged by irradiation, and the composite electrode can be easily removed after assembly.
Moreover, it is an object of the present invention to provide an electron gun electrode assembly for a color picture tube in which bonding and assembling are performed while maintaining high accuracy and good characteristics are obtained. [Means for Solving the Problems] In order to solve the above problems, according to the present invention, at least two tubular parts are formed by joining respective facing flanges to each other. In the electrode structure, a difference is provided between the overhanging dimension of the flange of one component forming the above flange joint and the overhanging dimension of the flange of the other component, and the two tubular components are held in correct relative positions. We decided to weld the flange facing parts to be joined. [Operation] By adopting the above means, the core metal of the assembly jig is not directly irradiated with the laser beam during the laser welding, so that the problems due to the damage of the core metal of the jig and the splash adhesion due to the laser beam irradiation are eliminated. As a feature of laser welding, it is possible to weld even if there is a slight gap between the facing flange surfaces to be joined, so it is possible to absorb the dimensional error of the two parts to be joined in the above gap, so after assembly It is possible to maintain high precision in the composite electrode. [Embodiment] FIG. 1 (a) is an enlarged sectional view of an essential part of an embodiment of the present invention. In the figure, 41 is a focusing electrode according to the present invention, 51 is a lower focusing electrode, 51B is a central electron beam passage hole of the lower focusing electrode, 51b is a flange of the lower focusing electrode, 61 is an upper focusing electrode, and 61B is an upper focusing electrode. The central electron beam passage hole, 61b is the flange of the upper focusing electrode, 77 is the irradiation direction of the laser light beam for welding,
Reference numerals 70 and 73 are substrates of the assembly jig, and 71 is a core metal of the jig. As shown in the drawing, a step δ is provided in the overhanging dimension of the flanges 51b and 61b to which the lower focusing electrode 51 and the upper focusing electrode 61 are to be joined by laser welding. At the time of welding, as shown in this figure, a laser light beam is emitted from the side with a small flange overhang, that is, from the outer upper side of the lower focusing electrode 51, in a direction 77 obliquely inclined by an angle θ with respect to the flange surface. In this case, in detail, as shown in FIG. 1B, the laser light beam A irradiates both the end surface 51c of the flange of the lower focusing electrode 51 and the upper focusing electrode 61b. As a result, the end surface 51c of the lower focusing electrode flange 51b and the upper focusing electrode flange 61c are
b and are welded, and the shape after laser welding is as shown in FIG. 1 (c). With both electrodes mounted on the assembly jig so as to hold the correct relative positions, the gap Δl remaining between the opposing flange surfaces of both electrodes hardly changed before and after laser welding, and A highly assembled focusing electrode 41 is obtained. According to the experiment, when the flange thickness of the lower focusing electrode and the upper focusing electrode is 0.4 mm and Δl = 0.05 to 0.10 mm, the flange step difference δ = 0.4 mm, that is, the flange thickness is approximately equal to the best assembly. It turns out that accuracy can be obtained. Further, since the laser light is applied to the flange surface at an angle θ, the core metal 71 of the jig is not damaged by the laser light. As described above, a highly accurate assembly electrode can be obtained by providing a difference in the overhanging dimension of the laser welding flange, and therefore the electron beam focusing state is good over the entire fluorescent surface, and a high quality image can be obtained. To be In the above description, between the flange surfaces to be joined,
The case of using the characteristics of laser welding by creating a gap has been explained, but a means that does not cause deformation of the component electrode in the assembly jig (for example, the jig can be elastically expanded and contracted slightly in the vertical direction). Even if there is no gap, if there is a difference in the bulging of the opposing flanges that should be joined, it is possible to irradiate the flange surface with laser light diagonally and weld it. It is possible to obtain an effect that there is no possibility that the core metal of the assembly jig is damaged by the laser light due to the unevenness of itself. [Effects of the Invention] As described above, according to the present invention, since the assembly is performed while keeping the parallel accuracy of the end faces of both component electrodes constituting the assembly electrode high, the focused state of the electron beam is good and a high quality image is obtained. It is possible to mass-produce color picture tube electron guns with high yield.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 (a) is an enlarged sectional view of an essential part of an embodiment of the present invention.
FIGS. 2 (b) and 2 (c) are diagrams for explaining flange welding according to the present invention, FIGS. 2 (a) and 2 (b) are sectional views of an example of a conventional in-line type electron gun, and FIG. FIG. 3 (b) and FIG. 4 are views for explaining a conventional assembling method of the focusing electrode, FIG. 5 is a perspective view of the conventional focusing electrode, and FIG. 6 is a conventional focusing electrode. It is a figure explaining the problem at the time of laser welding. 40, 41 ... Focusing electrodes, 50, 51 ... Lower focusing electrodes, 50B, 51B ...
Central electron beam passage hole of lower focusing electrode, 50b, 51b ... Flange of lower focusing electrode, 51c ... End face of flange of lower focusing electrode, 60,61 ... Upper focusing electrode, 60B, 61B ... Passing central electron beam of upper focusing electrode Holes, 60b, 61b ... Flange of upper focusing electrode, 71 ... Core of assembly jig, 77 ... Irradiation direction of laser light beam for welding.

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Masahiro Miyazaki               3300 Hayano Mobara-shi, Chiba Sun               Inside the Mobara factory (72) Inventor Yoshiaki Takahashi               3681 Hayano, Mobara-shi, Chiba Hitachi, Ltd.               Su Engineering Co., Ltd.                (56) References JP-A-60-163335 (JP, A)

Claims (1)

(57) [Claims] In an electron gun electrode assembly for a color picture tube, wherein at least two tubular parts are formed by joining mutually facing flanges, the flange overhanging dimension of one of the parts forming the flange joint and the other At least a part of the flange size of the component is different from that of the flange, and the end faces of the parts facing the flange that are different in the flange size and have a small size are joined by laser welding. An electron gun electrode assembly for a color picture tube characterized by the above. 2. The electron gun electrode assembly for a color picture tube according to claim 1, characterized in that the difference between the flange overhanging dimensions of the two tubular parts to be joined is set to be substantially equal to the flange wall thickness. 3. An electron gun electrode assembly for a color picture tube according to claim 2, characterized in that a gap of 0.05 to 0.1 mm is left between the opposed flange surfaces of the two tubular parts to be joined and laser welding is performed. .