JPH0558208B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a method of assembling an electron gun electrode assembly for a color picture tube.

[Background of the invention]

The assembly precision of the electron gun electrode assembly for color picture tubes greatly affects the focus characteristics, so it is necessary to improve the assembly precision of the electrode assembly in order to obtain a product with uniform focus characteristics.

FIG. 1 shows an example of a conventional bipotential focusing type in-line electron gun, in which (a) is a central sectional view on the long side of the electrode, and (b) is a central sectional view on the short side of the electrode.
In the figure, 1A, 1B, and 1C are cathodes that emit electron beams A, B, and C from their top surfaces, respectively;
2 is a control electrode that controls the electron beams A to C; 3 is an acceleration electrode that accelerates the electron beams A to C; 4 is a focusing electrode that focuses the electron beams A to C; a lower focusing electrode 5 and an upper focusing electrode 6 are They are pre-bonded and formed. 7 is an anode, and 8 is a convergence electrode.

Electron beam passing holes 2A to 2C, 3 are provided in the control electrode 2, acceleration electrode 3, and lower focusing electrode 5, respectively.
A to 3C and 5A to 5C are provided, and the upper focusing electrode 6 and anode 7 have three aperture holes 6A to 6C and 7A to 7C provided opposite to each other on their bottom surfaces.
and form three main lenses corresponding to the three electron beams A to C.

The general operating voltage of the electron gun is the voltage applied to the control electrode 2.
0V, 700V to acceleration electrode 3, about 7KV to focusing electrode 4,
25KV is applied to the anode 7.

In the electron gun configured in this way, the three electron beams A, B, and C, each of which has an electron beam amount controlled by the signal potential applied to the three cathodes 1A to 1C, are focused by the accelerating electrode 3 and the lower part. After receiving a slight focusing effect from the prefocus lenses formed between the holes facing the electrode 5, the picture tube (not shown) is moved by the main lenses formed by the upper focusing electrode 6 and the anode 7. It receives a focusing action so that it forms an image on the fluorescent surface of. At the same time, the electron beams A and C on both sides are tilted at an angle θ by a known means of slightly eccentrically eccentricizing the electron beam passing holes 7A and 7C of the anode 7 outward with respect to the electron beam passing holes 6A and 6C of the upper focusing electrode 6. and three electron beams A, B,
Let C converge to one point.

FIG. 2 is a top view of the focusing electrode 4 showing a cross section taken along the line PP in FIG. The electron gun has multiform glasses 9 disposed above and below that insulate and support the parts 2 to 7, and is housed in a cylindrical neck tube (not shown), so the cylindrical portion 6a of the upper focusing electrode 6 of the focusing electrode 4 is It has an oval shape with its major axis extending in the direction in which the holes 6A to 6C are arranged, and the joint portion of the flange portion 6b is inserted into and supported by the multiform glass 9. Note that the lower focusing electrode 5 is also formed in the same manner, although not shown.

The focusing electrode 4 is used by assembling a lower focusing electrode 5 and an upper focusing electrode 6 in advance using an assembly jig as shown in FIG. This figure shows a central cross section in the short axis direction of the assembly jig for the focusing electrode 4, and shows holes 6A to 6C of the upper focusing electrode 6 and the lower focusing electrode 5 in at least two core metals 11 planted on the substrate 10. hole 5A~
5C (6A, 6C and 5A, 5C are not shown) are fitted together, sandwiched between substrates 12, and a plurality of flange portions 6b and 5b pressed against each other are joined at resistance welding points 13 to be assembled.

By the way, the lower focusing electrode 5 and the upper focusing electrode 6
are manufactured by press-drawing a stainless steel plate with a thickness of about 0.3 mm, respectively.
The relative error in the parallelism of the upper and lower surfaces is larger in the minor axis direction of a than in the major axis direction. Therefore, in the assembly method shown in FIG. 3, the parallelism errors of the lower focusing electrode 5 and the upper focusing electrode 6 remain in the focusing electrode 4, and for example, as shown in FIG. is inclined.

In this way, when the bottom surface of the lower focusing electrode 5 is tilted, the electron beam B emitted from the cathode 1B passes through the acceleration electrode 3 and the beam passing hole 3B of the lower focusing electrode 5.
The beam is slightly focused by a prefocus lens formed by the upper focusing electrode 6 and the beam passing hole 7B of the anode 7, and is carried to the narrowly spaced upper side, that is, above the fluorescent surface of the picture tube. The beam enters eccentrically above the main lens and is focused.

Figure 4 shows the beam spot at the center of the fluorescent surface.
If the electron beam is incident on the center of the main lens,
As shown in figure a, core 2 with high electron beam density
0 and the low density halo 21 appear concentrically,
As shown in Figure 1b, when an electron beam is eccentrically incident on the main lens, the spherical aberration of the main lens causes it to be refracted more toward the edges, so the fourth
As shown in FIG. b, the core 20 and the halo 21 are eccentric.

In-line color picture tubes use a convergence method in which the magnetic field distribution of a deflection coil (not shown) is pink in the horizontal direction and barrel-shaped in the vertical direction, making the three electron beams coincident over the entire fluorescent surface. The horizontal bright line scanned in the direction is as shown in FIG.

FIG. 5a shows the case where the beam spot is deflected and scanned with no eccentricity of the halo 21 with respect to the core 20 as shown in FIG. A comparatively narrow halo portion 21B appears symmetrically above and below.
In the upper horizontal bright line 20A, the halo 21A is emphasized on the lower side, and in the lower horizontal bright line 20C, the halo 21C is on the upper side in the opposite direction. Hello 21 (21A~
21C) reduces the resolution of the image, that is, the focus characteristic, but this is not a problem if the images are concentric at the center.

However, when the beam spot with the halo 21 biased toward the core 20 is deflected and scanned as shown in FIG. 4b, the bright line 20C on the lower side of the fluorescent surface 22 as shown in FIG. Halo around 21C
is in the direction of disappearing, but the downward center halo 21B and the upper halo 21A are emphasized,
A serious drawback was that the image quality in this area was significantly degraded.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for assembling an electron gun assembly for a color picture tube, which can improve assembly accuracy and prevent fluctuations in focus characteristic quality.

[Summary of the invention]

In order to achieve the above object, the present invention provides two spacers that sandwich a plurality of spacers precisely machined to have the same length.
At least two cylindrical parts are stacked coaxially between two parallel substrates by inserting their respective holes into the core metal, and the cylindrical parts are stacked so that a gap of 0.05 to 0.5 mm is created in the stacked part of the cylindrical parts. The method is characterized in that the stacked parts are welded together using a laser by elastically urging the cylindrical parts in directions away from each other so that both end surfaces of the cylindrical parts are brought into close contact with the parallel substrates, respectively.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIG. The focusing electrode 40 is the lower focusing electrode 5 as in the conventional case.
0 and an upper focusing electrode 60, each having three electron beam passing holes 50A to 50C and 60A to
60C is provided. In the figure, only the central electron beam passing holes 50B and 60B are shown. The lower substrate 70 has the electron beam passing holes 50A to 50.
C and at least 2 inserted into 60A-60C
A book core bar 71 is arranged to be movable up and down with a spring 72. A plurality of pins 74 are arranged on the upper substrate 73 so as to be movable up and down by springs 75.
A plurality of spacers 76 are arranged between the lower and upper substrates 70 and 73, and these spacers 76 are approximately 0.3 mm longer than the sum of the lengths of each component 50 and 60.
Precision processing is performed so that the difference in length between the spacers 76 is 0.01 mm or less. Note that the flange portion 50b of the lower focusing electrode 50 is formed to have a small diameter so as not to engage with the pin 74.

Therefore, the lower focusing electrode 50 and the upper focusing electrode 60, which have a slight parallelism error on the upper and lower surfaces, connect the respective holes 50A to 50C and 60A to 60C to the core metal 71.
and press the upper substrate 73 in close contact with the spacer 76. As a result, the bottom focusing electrode 50 is pushed by the stepped portion of the core metal 71 by the biasing force of the spring 72 and its bottom surface is pressed against the upper substrate 73, and the upper focusing electrode 60 receives the biasing force of the spring 75. The flange portion 60b is pushed by the plurality of pins 74 so that the top surface is brought into close contact with the upper surface of the lower substrate 70. Since the lower substrate 70 and the upper substrate 73 have a high degree of parallelism due to the plurality of spacers 76, the bottom surface of the lower focusing electrode 50 and the top surface of the upper focusing electrode 60, which are in close contact with them, are held in a state of parallelism. Ru.

While held in this manner, a laser beam is irradiated from the direction of arrow 77 to separate the flange portions 50b and 60b.
are joined by welding in multiple places from the side. Since laser beam welding does not require mechanical stress, it is possible to assemble parts with high precision while maintaining parallelism and coaxiality of holes during setting.

As mentioned above, the spacer 76 is connected to each component 50, 60.
Because it is set approximately 0.3 mm longer than the sum of the lengths, even if each part has a parallelism error of approximately 0.05 mm and a length error of 0.05 mm,
The interval between and 60b is 0.1 to 0.5 mm. Therefore, the adhesion between the lower substrate 70 and the top surface of the upper focusing electrode 60 and between the upper substrate 73 and the bottom surface of the lower focusing electrode 50 is not impaired. Flange parts 50b, 60b
If the gap is too large, the joining accuracy by laser welding will decrease, so it is preferable that the gap is 0.05 to 0.5 mm.

FIG. 7 shows the focusing electrode 40 assembled in this manner, with reference numeral 78 indicating a plurality of laser welding points.

When the focusing electrode 40 with improved accuracy such as the parallelism and coaxiality of the upper and lower surfaces is used in an electron gun, the deflection of the electron beam by the prefocus lens as shown in FIG. 1b is eliminated. Since the electron beam is incident on the center of the main lens, there is no misalignment of the halo. Therefore, it is possible to obtain a color picture tube with improved focus performance over the entire fluorescent surface.

FIG. 8 shows another embodiment of the present invention, in which two intermediate cups 80, 81 are arranged between the lower focusing electrode 51 and the upper focusing electrode 61.
1 is welded and joined. The lower substrate 90 has holes 51A to 5 provided in the lower focusing electrode 51, the upper focusing electrode 61, and the intermediate cups 80 and 81, respectively.
1C, 61A-61C and 80A-80C, 81
A to 81C (51B, 61B, 80B, 8 in the figure)
At least two core metals 91 are installed to be inserted into the core (only 1B is shown). The upper substrate 92 has a core metal 9
A hole is formed into which the tip of No. 1 is inserted. The spacer 93 is connected to each component 51, 6 as in the previous embodiment.
It is approximately 0.3 mm longer than the sum of the lengths of 1, 80, and 81, and is precisely machined so that the difference in length between each spacer 93 is 0.01 mm or less. Further, a plurality of elastic bodies 94 are arranged between the flange portions 80b and 81b of the intermediate cups 80 and 81.

Therefore, the upper focusing electrode 61, intermediate cups 81, 80, and lower focusing electrode 51 are sequentially inserted into the core bar 91, the elastic body 94 is arranged between the intermediate cups 80, 81, and the upper substrate 92 is brought into close contact with the spacer 93. and press it. First, the flange 51b of the lower focusing electrode 51 and the flange 80b of the intermediate cup 80, and the flange 61b of the upper focusing electrode 61 and the intermediate cup 80 are connected.
1 flange 81b is connected to a plurality of resistance welding points 97, respectively.
Join with. Furthermore, the flange portions 8 of the intermediate cups 80 and 81 are irradiated with a laser beam from the direction of the arrow 95.
The spaced parts 0b and 81b are joined by welding at multiple locations from the side.

In this way, since the intermediate cups 80 and 81 are urged away from each other by the elastic body 94, the bottom surface of the lower focusing electrode 51 is in close contact with the upper substrate 92, and the top surface of the upper focusing electrode substrate 61 is in close contact with the lower substrate. 90, and both 51 and 61 are parallel, and the middle cup 8
0,81 are joined.

FIG. 9 shows the focusing electrode 41 assembled by such a method, and 96 indicates a welding point using a laser beam.

Although each of the above embodiments describes a method for assembling a focusing electrode for a bipotential focusing electron gun, the present invention can be similarly applied to an electrode structure of a multi-stage focusing electron gun formed from a plurality of electrode parts. Further, although the case where the focusing electrode has three holes has been described, the same applies if there is one or more holes.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, the parallel accuracy of both end surfaces and the coaxial accuracy of the electron beam passing holes provided on both end surfaces are ensured regardless of the parallelism error of each component, so that higher A highly accurate electron gun can be obtained, and a color picture tube with less variation in focus quality can be produced.

[Brief explanation of the drawing]

Figure 1 shows a conventional in-line electron gun, a
1 is a horizontal sectional view, b is a vertical sectional view, FIG. 2 is a top view of the focusing electrode taken along the line P-P in FIG. 4A and 4B are diagrams of the shape of the beam spot appearing on the fluorescent surface, and FIGS. 5A and 5B are state diagrams of horizontal bright lines obtained by scanning the beam spot shown in FIG. 4 on the fluorescent surface. FIG. 6 is a sectional view of essential parts showing an embodiment of the assembly method of the present invention, FIG. 7 is a perspective view of a focusing electrode obtained by the method of FIG. 6, and FIG. 8 is an assembly method of the present invention. 9th cross-sectional view of main parts showing another embodiment of
The figure is a perspective view of a focusing electrode obtained by the method of FIG. 8. 50, 51...Lower focusing electrode, 50B, 51B
...Electron beam passing hole, 50b, 51b...Flange portion, 60, 61...Top focusing electrode, 60B,
61B...Electron beam passage hole, 60b, 61b...
...Flange part, 70 ... Lower board, 71 ... Core metal,
72...Spring, 73...Upper board, 74...
Pin, 75...spring, 76...spacer,
77... Laser beam irradiation direction, 80, 81... Intermediate cup, 80B, 81B... Hole, 80b, 81b
...Flange portion, 90...Lower board, 91...Core metal, 92...Upper board, 93...Spacer, 94...
...Elastic body, 95... Laser beam irradiation direction.

Claims (1)

[Claims] 1. A method for assembling an electron gun electrode assembly for a color picture tube, in which at least two cylindrical parts are stacked and joined together, and at least one hole provided on each end face forms an electron lens with a counter electrode, At least two cylindrical parts are stacked coaxially between two parallel substrates that sandwich a plurality of spacers precision-machined to the same length, and the cylindrical parts are stacked coaxially through their respective holes inserted into the core metal. 0.05~ for the stacked part
The cylindrical parts are elastically urged in directions away from each other so as to create a gap of 0.5 mm, both end surfaces of the cylindrical parts are brought into close contact with the parallel substrates, and the stacked parts are welded together using a laser. A method for assembling an electron gun electrode structure for a color picture tube, characterized in that: