JPS6145345B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electron beam adjusting device for magnetically adjusting the beam position of a multi-electron beam cathode ray tube.

Color television receivers use cathode ray tubes in which three electron guns are arranged at the vertices of a triangle, or cathode ray tubes in which three electron guns are arranged on the same plane. In these cathode ray tubes, in a static state, in other words, when the electron beams emitted from the three-electron gun are not affected by any magnetic field, the three electron beams strike a predetermined dot on the fluorescent surface of the cathode-ray tube. It is configured to hit. For example, in a so-called in-line cathode ray tube in which three electron guns are arranged on the same plane, the central electron beam passes through the tube axis, and the other two electron beams pass through the central electron beam. arranged symmetrically with respect to the beam,
It is designed to provide good electron beam focusing on the fluorescent surface.

However, the cathode ray tubes actually used are manufactured with tolerances within an allowable range, so the electron beams emitted from the three-electron gun are focused at the phosphor surface. A situation may arise where this is not possible.

In such cases, an adjustable magnetic field created using a ring magnet is generally used to modify the trajectory of the electron beam so that the three electron beams strike the correct dots on the phosphor surface.

Magnet means 10 for generating an adjustable magnetic field is mounted between the deflection yoke ₁₃ on the net 12 of the cathode ray tube 11 and the electron gun ₁₄ , as shown in FIG. _c to adjust its focusing. This magnet means 10 is composed of two ring-shaped magnets 10 _a and 10 _b magnetized with four poles at equal intervals in the circumferential direction, as shown in FIG. 2, or as shown in FIG. 3. As shown, it is composed of two ring-shaped magnets 10 _c and 10 _d magnetized with six poles.

However, if the adjustable magnetic field is formed by two ring-shaped magnets as described above, a zero magnetic field cannot be obtained within the neck 12 no matter how the rotation of the ring-shaped magnets is adjusted. That is, since ring-shaped magnets are thick, even if two magnets are placed closely together, the centers of the magnetic fields generated from each magnet will be spaced apart by a certain distance. To explain this in detail using FIG. 4, which is exaggerated, for example, the ring-shaped magnet 1
Assuming that magnets 0 _a and 10 _b are arranged l apart from each other in the direction of the tube axis 16 as shown in Figure A, in order to obtain a zero magnetic field within the net 12, the magnet 10 _a must have a N pole, for example, as shown in Figure B. If the magnetic field distribution B _a is from magnet 1
0 _b becomes the magnetic field distribution B _b from the S pole. Naturally, since the strength and distribution of the magnetic fields generated by the magnets 10 _a and 10 _b are made the same, the magnetic field distribution B
When the centers 17 and 18 of _a and _Bb coincide, the adjustable magnetic field on the tube axis 16 becomes zero.

However, in reality, two ring-shaped magnets _10a ,
Since 10 _b is l apart as mentioned above, magnet 1
Even if the rotation of 0 _a and 10 _b is adjusted, the electron beam will still be affected by the magnetic field generated by each magnet. FIG. 4C shows the trajectory of the electron beam emitted from the electron guns 14 _a and 14 _b located on both sides of the three electron guns arranged in-line. When the ring-shaped magnets _10a and _10b are adjusted to have a zero magnetic field, if the adjustable magnetic field in the net 12 is zero, the electron beam will reach the fluorescent surface without being subjected to static deflection. It should be.

However, as described above, the ring-shaped magnet 10
Since the centers of the magnetic field distributions of magnets 10 a and 10 _b are far apart, the electron beams are affected by the magnetic fields from the respective magnets 10 _a and 10 _{b ,} and the electron beams 15 _a and 15 _c in Figure C
is deflected as follows.

This means that the electron beams 15 _a , 15 _b , 15 _c emitted from the three electron guns 14 _a , 14 _b , 14 _c are subjected to unwanted deflection before being deflected by the deflection magnetic field of the deflection yoke 13 . It means. Therefore, since the position where the three electron beams enter the deflection magnetic field is different from the original position, the deflection trajectory of the electron beam is symmetrical with respect to the tube axis 16 in the horizontal deflection direction, the vertical deflection direction, or both directions. First, there were drawbacks such as deformation of the screen and misfocusing of the electron beam.

The present invention has been made in view of the above points, and provides an electron beam adjustment device configured to adjust the adjustable magnetic field acting on the electron beam passing through the network of a cathode ray tube to zero magnetic field.

FIG. 5 explains the outline of the device of the present invention,
The magnet means 20 for generating an adjustable magnetic field is composed of a set of three ring-shaped magnets 20 _a , 20 _b , 20 _c , and these magnets are arranged in the direction of the tube axis 20 _a , 20
_c and _20b , and are closely held using a holder 19 that can be inserted into and fixed in the cathode ray tube network. Ring-shaped magnets 20 _a , 20 _b ,
20 _c is N at equal angles in the circumferential direction, for example, at every angle of 180°, 90°, 60°, etc. around the tube axis 16.
Two, four, and six south poles are magnetized. Figure 6 shows an in-line array of electron beams _15a , 1
The ring-shaped magnets 20 _a , 20 b , and 20 _c magnetized with four poles at a 90° angle and used in the _magnets 5 _b and 15 _c are shown.

The three ring-shaped magnets 20 _a , 20 _b , 20 _c are
The electron beam may be statically deflected by adjusting the rotation in any clockwise or counterclockwise direction, but when actually used in a television receiver,
Ring-shaped magnets 20 _a on both sides of ring-shaped magnet 20 _c ,
20 _b is simultaneously rotated in the same direction and at the same angle with respect to the magnet 20 _c , and positioned so that the same magnetic pole (for example, N pole) is located on a plane passing through the tube axis 16 . The magnets 20 _a and 20 _b are magnetized to approximately the same amount of magnetism, while the magnets 20 _{c are}
It is magnetized to a magnetic quantity with a magnetic field strength that is approximately equal to the composite magnetic field of 0 _b .

In the above configuration, three ring-shaped magnets 20
Even if _a , 20 _b , and 20 _c are close together, the center of the magnetic field is l ₁ and l ₂ apart due to the thickness of each magnet, as shown in Fig. 7A, which is exaggerated (usually l ₁ = l ₂ ). Therefore, for example, from the S poles of the ring-shaped magnets 20 _a and 20 _b , a magnetic field distribution B of H _A and H _B as shown in FIG. 7B is generated, and these magnetic fields form a combined magnetic field distribution H' _C It acts on the electron beam as (=H _A +H _B ). The magnetic field center of this magnetic field distribution H' _C almost coincides with the magnetic field center of the ring-shaped magnet 20 _c . For example, from the N pole of the ring-shaped magnet 20 _c , a magnetic field distribution H _C corresponding to the composite magnetic field distribution H' _C is generated and acts on the electron beam.

From the above, ring-shaped magnets 20 _a , 20 _b , and 2
The force by which 0 _c moves the electron beams 15 _a and 15 _b is canceled, and the N pole (or S pole) of the ring magnet 20 _c
and the S _pole (or _N
When the two poles overlap, the trajectory of the electron beam does not substantially change. Therefore, at this time, since the adjustable magnetic field is a zero magnetic field, the three electron beams are focused at the center of the screen without being subjected to static deflection.

FIGS. 8 to 11 show specific examples of the apparatus of the present invention. In FIG. 8, the holder 21 includes a cylindrical portion 22 on which the ring-shaped magnets 20 _a , 20 _b , and 20 _c are attached, and gears 24 and 25 that rotate the magnets 20 _a , 20 _b , and 20 _c .
After installing the gears 24, 25 and the ring-shaped magnets _20a , _20b , _20c , the lid body 28 of FIG. The hook part 29 provided at the appropriate position of the lid body 28 is hooked into the position of the recessed part 30 of the holder 21 and fixed. The lid body 28 has a flange part 31 that fits into the cylindrical part of the holder 21 and a plate part 3 that covers the expansion chamber part 23.
2, and the plate portion 32 has a ring-shaped magnet 20.
A protruding shaft 34 is provided to support a gear 33 that meshes with one of the gears _a and _20b .

The ring-shaped magnet 20 _c is the ring-shaped magnet 20 _a , 20
The outer periphery is made to have a larger diameter _{than b ,} and teeth are carved on each circumferential surface, _and as shown in FIGS. 25, the ring-shaped magnets _20c are simultaneously rotated. The gear 25 is integrally provided with a large-diameter pickup wheel, and a portion thereof is exposed outside the bulge chamber 23 so that the gear 25 can be rotated from outside the bulge chamber 23.

Note that the holder in the present invention is not limited to the above-mentioned example, but may be one related to a deflection yoke bobbin.

As described above, the device of the present invention can adjust the adjustable magnetic field that statically deflects the electron beam to zero magnetic field, so when the tolerance of the electron gun arrangement in the cathode ray tube is almost zero, the electron beam There will be no situation where this will result in an involuntary bias.

Therefore, the electron beam does not draw a deflection trajectory that is distorted by the dynamic deflection magnetic field of the deflection yoke, eliminating deformation of the screen, defocusing of the electron beam, and convergence error especially at the edges of the screen. You can.

[Brief explanation of the drawing]

Figure 1 is a schematic configuration diagram of a conventional magnet means attached to a cathode ray tube, Figures 2 and 3 are plan views of a ring-shaped magnet, and Figure 4 is for explaining the operation of the conventional magnet means. , A indicates the arrangement of the magnets, B indicates the magnetic field distribution generated from the magnets, and C indicates the electron beam trajectory deflected by the magnetic field distribution of B.
The figures are a side view with a part cut away showing the schematic structure of the electron beam adjustment device of the present invention, FIG. 6 is a plan view showing an example of a ring-shaped magnet used in the device of the present invention, and FIG.
The figure is for explaining the operation of the device of the present invention.
A shows the arrangement of the magnets, B shows the magnetic field distribution generated from the magnets, and FIGS. 8 to 11 show specific examples of the device of the present invention. FIG. 8 is a front view of the holder, and FIG. 9 10 is a sectional view taken along line XX in FIG. 8, and FIG. 11 is a sectional view taken along line YY in the same figure. In the figure, 19 is a holder, 20 is a magnet means, 20
_a , _20b , and _20c are ring-shaped magnets.

Claims (1)

[Claims] 1 3 Among the three magnetizing bodies arranged in the tube axis direction on the net of a color cathode ray tube having a net surrounding the trajectory of the electron beam, the magnetic field strength of the magnetizing body at the center position and the magnetic generating bodies at both ends a magnetic means capable of adjusting the adjustable magnetic field acting on the electron beam to zero magnetic field by substantially equalizing the combined magnetic field strength of the electron beam;
An electron beam adjustment device comprising a holder for supporting the means on the neck.