JPH0630217B2 - Method for manufacturing electron gun electrode assembly for color picture tube - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to an in-line type electron gun electrode assembly for a color picture tube in which variation in focus characteristics is prevented, and a manufacturing method thereof.

[Background of the Invention]

Generally, in an electron gun for a color picture tube, the assembling accuracy has a great influence on the focus characteristic, and therefore, the assembling accuracy needs to be improved in order to obtain an electron gun having a uniform focus characteristic.

FIG. 1 is a horizontal sectional view of an essential part showing an example of a conventional bipotential focusing type in-line type electron gun. In the figure, 1A, 1B, and 1C are cathodes that emit three electron beams from the top surface, 2 is a control electrode that controls the electron beam, 3 is an accelerating electrode that accelerates the electron beam, and 4 is the electron beam focusing This focusing electrode 4 is a focusing electrode
Is formed by previously combining the lower focusing electrode 5 and the upper focusing electrode 6. 7 is an anode. In this case, the electron beam passage holes 2A, 2B, 2C, 3A, 3B, 3C and 5 for passing the three electron beams through the respective electrodes 2, 3 and 5 described above.
A, 5B, 5C are provided, and the upper focusing electrode 6 and the anode 7 are provided with three electron beam passage apertures 6A, 6B, 6C and 7A, 7B, 7C facing the respective bottom surfaces. Thus, three main lenses corresponding to the three electron beams are formed. In this case, the operating voltage of the electron gun is 0V to the control electrode 2, about 700V to the acceleration electrode 3, about 7KV to the focusing electrode 4, and about 25KV to the anode 7.

In the electron gun constructed in this way, three cathodes
Three electron beams A, B, C whose electron beam amounts are controlled by the signal potentials given to 1A, 1B, 1C
Are holes 3A facing the accelerating electrode 3 and the lower focusing electrode 5,
After being slightly focused by the prefocus lens formed between 3B, 3C and 5A, 5B, 5C, the respective holes 6A, 6B, 6C and 7A facing the upper focusing electrode 6 and the anode 7 are formed. , 7B, 7C, the main lens forms a focusing action so as to form an image on the picture tube fluorescent surface (not shown). At the same time, the electron beams A and C on both sides are inclined at an angle θ by a known means for slightly eccentricizing the electron beam passage holes 7A and 7C of the anode 7 to the electron beam passage holes 6A and 6C of the upper focusing electrode 6. Then, the three electron beams A, B, and C are converged at one point. In addition, 8 is a convergence electrode.

FIG. 2 is a plan view of the focusing electrode 4 shown in the section II 'of FIG. In the figure, the electron gun has a multi-form glass 9 for insulating and supporting each electrode component arranged above and below and is housed in a cylindrical neck tube (not shown). The holes 6A, 6B, and 6C have an elliptical shape having a major axis in the arrangement direction, and the joint portion of the flange 62 is inserted into the multi-form glass 9 and supported.

However, the electron gun having the above-mentioned structure has the following problems.

That is, the lower focusing electrode 5 and the upper focusing electrode 6 are manufactured by press-drawing a stainless steel plate having a thickness of about 0.3 mm, respectively, and combining the two to form the focusing electrode 4. There is a problem in that the relative error in the parallelism between the upper and lower surfaces in the minor axis direction of the tubular portions of the electrodes 5 and 6 is larger than that in the major axis direction. That is, FIG. 3 shows a cross section of the assembly jig for the focusing electrode 4 in the minor axis direction. In FIG. 3, at least two cored bars 11 planted in the first substrate 10 are used to focus the upper focus. The hole 6B of the electrode 6 and the hole 5B of the lower focusing electrode 5 are fitted to each other, and the flange portions 62 and 52 sandwiched by the second substrate 12 and pressed against each other are joined at a plurality of resistance welding points 40 to be assembled. To be However, according to such an assembling method, the parallelism error between the lower focusing electrode 5 and the upper focusing electrode 6 remains in the focusing electrode 4.

Further, FIG. 4 shows a vertical cross section of the central electron gun, showing a case where the bottom surface of the lower focusing electrode 5 is inclined. In the figure, the electron beam B emitted from the cathode 1B is slightly focused by the prefocus lens formed by the electron beam passage holes 3B and 5B of the accelerating electrode 3 and the lower focusing electrode 5, and at the same time The light is deflected to a narrow upper side, that is, to the upper side of the picture tube fluorescent surface, and eccentrically enters and is focused on the upper side of the main lens formed by the electron beam passage holes 6B and 7B of the upper focusing electrode 6 and the anode 7. Fig. 5 shows the beam spot at the center of the fluorescent surface. When the electron beam is incident on the center of the main lens, the core 20 with a high electron beam density and the halo with a low density are shown in Fig. 5 (a). 21 and 21 appear concentrically, but as described with reference to FIG. 4, when the electron beam is eccentrically incident on the main lens, the spherical aberration of the main lens causes greater refraction toward a portion closer to the end.
The core 20 and the halo 21 'are eccentric as shown in FIG. For this phenomenon, in the in-line type color picture tube, the magnetic field distribution of the deflection coil (not shown) is set to the pink direction in the horizontal direction and the barrel shape in the vertical direction to adopt the convergence method in which the three electron beams are aligned over the entire fluorescent surface. Therefore, the horizontal bright line obtained by scanning the electron beam in the horizontal direction is as shown in FIG. That is, FIG. 6 (a) is shown in FIG.
It shows a case where the beam spot in the state where the halo 21 is not eccentric to the core 20 as shown in (a) is deflected and scanned, and in the center of the fluorescent surface 30, the upper and lower sides of the bright line 22 having a high electron beam density. A relatively narrow halo portion 23 appears symmetrically. In the upper horizontal bright line 24, the halo 25 is emphasized downward, and in the lower direction, it is in the opposite direction. Here, the halo lowers the resolution of the image, that is, the focus characteristic, but it does not cause a problem when the center is concentric. However, as shown in FIG. 5 (b), when the beam spot in which the halo 21 'is offset with respect to the core 20 is deflected and scanned, as shown in FIG. 6 (b), Although the halo disappears around the bright line 28, there is a serious drawback that the central halo 27 and the upper halo 29 facing downward are emphasized and the image quality of this portion is significantly deteriorated.

[Object of the Invention]

Therefore, the present invention has been made to solve the above-mentioned conventional drawbacks, and an object of the present invention is to provide an electron gun electrode assembly for a color picture tube in which variation in focus characteristics is prevented. Another object of the present invention is to provide a manufacturing method capable of stably and accurately producing such an electron gun electrode assembly.

[Outline of Invention]

In order to achieve such an object, the present invention is to provide a joining portion which is partially connected to a predetermined portion of the overlapping portion by axially combining cylindrical electrodes having different inner and outer diameters. Further, when joining the overlapped portions, the bottom surfaces of both electrodes are held in parallel and irradiated with laser light to be fixed by welding.

Example of Invention

 Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 7 is a sectional view of an essential part for explaining an example of an assembling method of the electron gun electrode assembly for a color picture tube according to the present invention. First, an assembly jig will be described before describing the present invention. That is, in the figure, 100 is a first substrate, 101 is a hole formed in the first substrate 100, and is movable upward and downward by the elastic force of a first spring 102, and the first substrate 100 is movable. At least 2 cores, which are planted so as not to separate from the
3 is a second substrate arranged above the first substrate 100 and having a hole for inserting the leading end portion of the cored bar 101, and 104 is a second substrate.
At least two pins that are movable in the upward and downward directions by the elastic force of the second spring 105 in the holes formed in the base plate 103 and that are implanted so as not to separate from the second base plate 103,
Reference numeral 106 denotes a spacer that sets the distance between the opposing surfaces of the first substrate 100 and the second substrate 103 to a dimension approximately equal to the length of the assembly component. Similarly, at least two spacers 106 are also provided and each spacer 106 has the same length. Precision machined so that the difference is 0.01 mm or less.

Next, a method of assembling the electron gun electrode using the assembling jig configured as described above will be described. First, the lower focusing electrode 5'and the upper focusing electrode 6 each having a thin cylindrical portion having an inner diameter of about 0.3 mm between the inner diameter of the upper focusing electrode 6 and the entire circumference thereof are connected to the respective electron beam passage holes 5B '. And 6B are inserted into the core metal 101, and the second substrate 103 is brought into close contact with the spacer 106 and pressed. In this case, the lower focusing electrode 5'is connected to the first spring 10
Due to the elasticity of 2, the bottom surface is pressed against the second substrate 103 by being pushed by the stepped portion of the core metal 101, and the upper focusing electrode 6 is
The flange portion 62 is pushed by the plurality of pins 104 by receiving the elastic force of the spring 105, and the top surface is brought into close contact with the top surface of the first substrate 100. Here, the first substrate 100 and the second substrate 1
Since 03 has a high degree of parallelism due to the plurality of spacers 106, the bottom surface of the lower focusing electrode 5 ′ and the top surface of the upper focusing electrode 6 which are in close contact with each other are held in a highly parallel state.
Further, the cylindrical portion of the lower focusing electrode 5'is set so that the entire circumference of the cylindrical portion of the upper focusing electrode 6 has a gap of about 0.3 mm. Even if there is a tilt error in the gap, the gap is absorbed by this gap, so that even with the current pressing technology, the gap around the entire circumference is sufficiently set within 0.05 to 0.5 mm, and a contact portion is not formed. Therefore, the adhesion between the top surface of the first substrate 100 and the upper focusing electrode 6 and the bottom surface of the second substrate 103 and the lower focusing electrode 5'is not disturbed. Thus, the lower focusing electrode 5'and the upper focusing electrode 6
While holding and, the laser beam 110 is irradiated from the side surface to weld and join a plurality of overlapping portions of the tubular part from the side surface. In this case, if the gap between the inner and outer tubular parts is too large,
Since the joining strength due to laser welding decreases, it is desirable that the distance be about 0.5 mm or less. In addition, since welding with laser light does not require mechanical stress, it is possible to assemble parts with high precision while maintaining parallelism and coaxiality of holes at the time of setting. FIG. 8 is a perspective view of the focusing electrode 4'assembled by such a method, and 111 is a plurality of welding points by laser light.

When the focusing electrode 4'having improved parallelism and coaxiality of the upper and lower surfaces is used in the electron gun, the electron beam is not deflected by the prefocus lens as described with reference to FIG. Is incident on the center of the main lens,
Therefore, it is possible to produce a color picture tube having an improved focus characteristic on the entire fluorescent surface without the halo being biased. Further, according to such a method, the focusing electrode 4 '
The length is determined by the plurality of spacers 106 that are processed with high precision, so that it is not affected by the length error between the lower focusing electrode 5'and the upper focusing electrode 6. Further, by changing the length of the overlapping portion of the fitting, it is possible to construct the focusing electrodes 4'having different lengths by the same component, which is excellent in mass production.

In addition, in the above-described embodiment, the method of assembling the focusing electrode for the bipotential focusing type electron gun has been described, but the present invention is not limited to this, and a multi-stage focusing method formed from a plurality of electrode parts. It is needless to say that the same effect as described above can be obtained even when applied to the electron gun structure.

〔The invention's effect〕

As described above, according to the present invention, the electrode structure composed of a plurality of parts, regardless of the parallelism error of each part,
By ensuring the parallel accuracy of both end surfaces and the relative accuracy of the electron beam passage holes provided on both end surfaces, a high-precision electron gun can be obtained, so that a color picture tube with extremely few fluctuations in focus characteristics is stable. It is possible to obtain an extremely excellent effect that it can be produced with good performance.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a main part showing a configuration and an operating state of a conventional in-line type electron gun, FIG. 2 is a plan view of a focusing electrode showing a II ′ cross section of FIG. 1, and FIG. 3 is a conventional focusing. FIG. 4 is a longitudinal sectional view of an in-line type electron gun using a conventional focusing electrode, and FIGS. 5 (a) and 5 (b) are beam spots appearing on the fluorescent surface. Figure showing the shape, No. 6
5 (a) and 5 (b) are plan views showing the state of horizontal bright lines obtained by scanning the beam spot shown in FIG. 5 on the fluorescent surface, and FIG. 7 is a diagram showing the manufacture of an electron gun electrode assembly for a color picture tube according to the present invention. FIG. 8 is a sectional view of an essential part for explaining an embodiment of a method, and FIG. 8 is a perspective view showing an embodiment of an electron gun electrode assembly for a color picture tube according to the present invention. 4 '... Focusing electrode, 5' ... Lower focusing electrode, 5B '... Electron beam passage hole, 6 ... Upper focusing electrode, 6B' ... Electron beam passage hole, 62 ... Flange, 100 ... First Board of 1
01 ...... core metal, 102 ...... first spring, 103 ...... second substrate, 104 ...... pin, 105 ...... second spring, 106 ...
… Spacer, 110 …… Laser light, 111,112 …… Welding point

Front page continuation (72) Inventor Ryo Endo 3300, Hayano, Mobara-shi, Chiba Inside the Mobara factory, Hitachi, Ltd. (56) References JP 48-80272 (JP, A) Actual development 55-39640 (JP, U) Japanese Patent Publication Sho-31-682 (JP, B1)

Claims (1)

[Claims] 1. A first cylindrical electrode and a second cylindrical electrode, which have mutually different inner and outer diameters and are formed with overlapping portions having a clearance of 0.05 to 0.5 mm over the inner and outer circumferences. To
Inserting the respective electron beam passage holes into a plurality of cored bars that are movably planted vertically in the first substrate and combining them in the axial direction, and the step of the cored bar for the second The bottom surface of the tubular electrode is pressed against a second substrate arranged to face the first substrate, and the first tubular shape is formed by a plurality of pins vertically movably planted on the second substrate. The bottom surface of the first tubular electrode is pressed against the first substrate while pressing the flange portion of the electrode to hold the bottom surface of the first tubular electrode and the bottom surface of the second tubular electrode in parallel. And a step of irradiating a laser beam to the overlapping portion of the first tubular electrode and the second tubular electrode to weld and fix the first tubular electrode and the second tubular electrode. A method for manufacturing an electron gun electrode assembly for a color picture tube, which comprises at least.