JP2746932B2 - Magnet device for color CRT - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an external magnet type magnet device for adjusting the static convergence and the illuminance of a color cathode ray tube by external magnetization.

2. Description of the Related Art A color cathode ray tube is provided with a magnet device for adjusting static convergence and the brightness at the center of a screen in order to absorb errors in parts and manufacturing variations.

Conventional magnet devices are described, for example, in U.S. Pat.
As shown in the specification, a plurality of magnet rings preliminarily magnetized to 2, 4, and 6 poles are rotatably mounted on a neck portion of a color cathode-ray tube, and these magnet rings are rotated. I am adjusting.

However, this structure has a very large number of parts, and it is necessary to magnetize each magnet ring with high precision, resulting in an increase in cost. In addition, the adjustment needs to rely on a highly skilled worker, and it is extremely difficult to adjust in a short time.

In order to solve such a problem, for example, as shown in U.S. Patent No. 4,138,628, U.S. Patent No. 4,159,456, U.S. Patent No. 4,162,470, a barium ferrite sheet is directly wound around a net portion. The barium ferrite sheet is fixed using a tie band or the like, and is magnetized at a predetermined intensity at a plurality of positions on the barium ferrite sheet, and is multipolar magnetized so as to generate a magnetic field for achieving a desired correction. Has been proposed.

[Problems to be solved by the invention]

In the above prior art, the difference in the amount of magnetization is 1000 times as large as that for obtaining the optimum magnetization pattern.However, since there is a magnetized surface over the entire circumference of the sheet, when the amount of magnetization increases, the adjacent magnetic poles And the optimum magnetization pattern cannot be obtained.

Also, barium ferrite has a large magnetization temperature characteristic of about -0.2% / ° C, and its characteristics change due to a rise in the temperature of the neck portion and the cabinet, a large static convergence drift, and a high-precision holding required for display applications. Is difficult.

In order to solve such difficulties, a plurality of pole pieces are fixed to a pole piece holder made of a non-magnetic material attached to the neck of a color cathode ray tube, and these pole pieces are magnetized before use. As a result, a magnet device for a color cathode-ray tube has been developed in which the static convergence and the purity of the color cathode-ray tube are adjusted, and this type of magnet device for a color cathode-ray tube is disclosed in, for example, JP-A-55-27781. This is disclosed in, for example, a microfilm of JP-A-57-1443837 (see Japanese Utility Model Application Laid-Open No. 59-47958) and JP-A-55-27781.

In this case, a magnet device for a color cathode ray tube disclosed in Japanese Patent Application Laid-Open No. 55-27781 discloses a plurality of (4 in the illustrated example) Magnetic pole pieces are fixed at substantially equal intervals, and the magnet device for a color cathode ray tube disclosed in the microfilm of Japanese Utility Model Application No. Sho 57-143837 has a ring-like shape in which the center hole is inserted into the neck portion. A plurality of (four in the illustrated example) pole pieces having a small temperature coefficient are embedded at substantially equal intervals on one side surface of the pole piece holder.
The magnet device for a color cathode ray tube disclosed in Japanese Patent Application Laid-Open No. 55-27781 discloses a plurality of (eight in the illustrated example) pole pieces on a peripheral surface of a cylindrical pole piece holder having a central hole inserted into a neck portion. It is a structure fixed at substantially equal intervals.

However, the magnet device for a color cathode-ray tube disclosed in JP-A-55-27781 has a configuration in which a plurality of magnetic pole pieces are fixed to a disk-shaped portion of a magnetic pole piece holder that protrudes in a flange shape, It is difficult to arrange a plurality of pole pieces close to the outer wall of the neck portion, it is difficult to perform high sensitivity adjustment of static convergence and purity based on the plurality of pole pieces, and it is difficult to arrange other various types of color cathode ray tubes. There is a problem that the protruding disk-shaped portion becomes an obstacle when the characteristics are adjusted.

Further, the magnet device for a color cathode ray tube disclosed in the microfilm of Japanese Utility Model Application No. Sho 57-143837 has a plurality of pole pieces embedded inside a ring-shaped pole piece holder. Not only can the problem of the magnet device for a color cathode ray tube disclosed in Japanese Patent No. 27781 be solved, but also because the pole pieces having a small temperature coefficient Is small, and the drift of the adjustment of the static convergence and the purity with respect to the ambient temperature fluctuation can be reduced, but the configuration is such that a plurality of pole pieces are embedded in one side surface of the ring-shaped pole piece holder. Therefore, in order to obtain such a magnet device, many complicated manufacturing processes are required, and the magnet device becomes expensive. There is a new problem that.

Further, the magnet device for a color cathode-ray tube disclosed in JP-A-55-27781 has a configuration in which a plurality of magnetic pole pieces are fixed to the peripheral surface of a cylindrical magnetic pole piece holder,
In view of the mechanical strength of the pole piece holder to which the plurality of pole pieces are fixed, it is difficult to dispose the plurality of pole pieces close to the outer wall of the neck portion, so that static convergence and purity based on the plurality of pole pieces are difficult. It is difficult to perform the adjustment with high sensitivity, and when attaching a plurality of pole pieces to a cylindrical pole piece holder, it is necessary to have a fixing strength that can withstand various environmental changes. In this respect, there is a problem that a design constraint is generated.

The present invention solves these problems altogether, and its object is to make it easy and inexpensive to manufacture and to adjust the sensitivity with high sensitivity. It is another object of the present invention to provide a color CRT magnet device having excellent temperature characteristics.

[Means for solving the problem]

In order to achieve the above object, a magnet device for a color cathode ray tube according to the present invention is a ring-shaped pole piece holder made of a non-magnetic material, the center hole into which the neck portion of the color cathode ray tube is inserted, and the periphery of the ring. A pole piece holder having a plurality of pole piece insertion holes radially from a surface toward a center hole, a plurality of metal alloy pole pieces inserted and fixed in the plurality of pole piece insertion holes, respectively, and a pole piece. Attachment means for attaching the holding body to the neck portion.

[Action]

Since each pole piece is mounted in a pole piece insertion hole provided in the pole piece holder, when the pole piece holder is fixed to the neck portion, the pole piece position is fixed, and The position of the magnetic pole does not change due to the displacement of the use coil.

In addition, since adjacent pole pieces are separated by the non-magnetic material of the pole piece holder, even if the amount of magnetization on each pole piece is large in order to optimize the static convergence and the spur, the magnetization surface Can be prevented from expanding, and the deviation of the magnetic pole due to the amount of magnetization is eliminated.

Further, since the pole piece is made of a metal alloy, for example, when a rare earth cobalt or an Fe—Cr—Co alloy is used, the temperature change after magnetization is −0.03% / ° C., which is about the same as that used conventionally.
1/10 and small.

Furthermore, since the pole pieces are inserted and fixed in a plurality of pole piece insertion holes provided on the peripheral surface of the ring-shaped pole piece holder, the plurality of pole pieces are arranged close to the outer wall of the neck portion. It is possible to perform static convergence and purity adjustment with high sensitivity, and the means for fixing a plurality of pole pieces to a ring-shaped pole piece holder is simple and reliable. And an inexpensive magnet device for a color CRT can be obtained.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. A deflection yoke 2 is mounted on a funnel portion of the color cathode ray tube 1, and a pole piece holder 4 of a magnet device 3 is fastened and fixed to a neck portion 1a by a fastening band 5 and a fixing screw 6. The pole piece holder 4 is made of a non-magnetic material, and is provided with a plurality of pole piece insertion holes 4a radially. Each pole piece insertion hole 4a has a rare earth cobalt or Fe
A magnetic pole piece 7 made of a metal alloy such as a Cr-Co alloy is inserted and fixed.

Then, the pole piece holder 4 is fastened to the neck portion 1a by the tightening band 5
The pole piece 7 is tightened and fixed with the fixing screw 6.
Is held at an accurate position with respect to the electron guns R, G and B.
With the pole piece holder 4 having the pole pieces 7 attached to the color cathode-ray tube 1, magnetization corresponding to the correction amount required for each pole piece 7 is performed from outside using a magnetizing coil (not shown). Thus, the static convergence and the pirity are adjusted. This adjustment will be described with reference to FIG.

FIG. 3 (a) shows a case in which both side beams are adjusted in opposite directions in the vertical direction. This adjustment is performed by the pole pieces 7A, 7C, 7E and 7G. FIG. 3B shows the case where the side beam is adjusted in the opposite direction to the left and right.
Performed by FIG. 3C shows a case where the side beam is adjusted by moving the side beam in the same direction in the left-right direction.
A, 7B, 7D, 7E, 7F, and 7H are used. In an actual color CRT, the necessary correction amount is a combination of these, and accordingly, the magnetization is also in a magnetized state in which these are superimposed.

Thus, each pole piece 7 (7A-7H) is a pole piece holder 4
, The pole piece holder 4 is connected to the neck 1a.
In this state, the position of the magnetic pole piece 7 is fixed, and the position of the magnetic pole does not change due to the displacement of the magnetizing coil. In addition, since the adjustment is performed by the independent magnetic pole pieces 7, mutual interference can be prevented even if the adjacent magnetic force difference caused by the adjustment of the static convergence and the adjustment of the pyura is large. Also, since the pole piece 7 is made of a metal alloy,
Even when the temperature of the network rises during operation, the change in the magnetic flux density is small, and the change in the static convergence and the adjustment amount of the pirity can be ignored in practical use.

FIG. 4 shows another embodiment of the present invention. In this embodiment, the pole piece holder 4 is integrated with the rear part of the deflection yoke 2. The other structure is the same as that of the above embodiment, and the description thereof will be omitted.

Even with such a configuration, the same effect as in the above embodiment can be obtained. Further, in this embodiment, the pole piece holder 4 is completed by merely attaching the deflection yoke 2 to the color cathode ray tube 1, and the variation in the attachment position in the tube axis direction is suppressed. Further, there is an effect that the fastening band 5 and the fixing screw 6 are shared.

〔The invention's effect〕

ADVANTAGE OF THE INVENTION According to this invention, the position of a magnetic pole does not generate | occur | produce and there exists an effect that there is no deviation of the magnetic pole by the amount of magnetization, and the magnet apparatus for color cathode-ray tubes which has excellent temperature characteristics is obtained.

Further, according to the present invention, since the pole pieces are inserted and fixed in the plurality of pole piece insertion holes provided on the peripheral surface of the ring-shaped pole piece holder, the plurality of pole pieces are fixed to the outer wall of the neck portion. Can be arranged close to the, and it is possible to perform static convergence and purity adjustment with high sensitivity, and a plurality of pole pieces are fixed to the ring-shaped pole piece holder on it There is an effect that the means for performing this operation is simple, can be securely fixed, and an inexpensive magnet device for a color CRT can be obtained.

[Brief description of the drawings]

FIG. 1 is a side view of a magnet device according to an embodiment of the present invention mounted on a color cathode ray tube, and FIG.
3A, 3B and 3C are explanatory views showing the relationship between the magnetized state of the pole pieces and the movement of the electron beam, and FIG. 4 is a magnet according to another embodiment of the present invention. It is a side view of an apparatus. DESCRIPTION OF SYMBOLS 1 ... Color cathode ray tube, 1a ... Network part, 2 ... Deflection yoke, 3 ... Magnetic device, 4 ... Magnetic pole piece holder, 4a ... Magnetic pole piece insertion hole, 7, 7A-7H ... Magnetic pole piece.

Continuation of the front page (72) Inventor Norio Tsukii 3300 Hayano Mobara-shi, Chiba Pref. JP-A-55-27781 (JP, A) JP-A-63-138633 (JP, A) Actually open sho 59-47958 (JP, U)

Claims (1)

(57) [Claims] 1. A ring-shaped pole piece holder made of a non-magnetic material, comprising: a central hole into which a neck portion of a color cathode-ray tube is inserted; and a plurality of radially extending from the peripheral surface of the ring toward the central hole. A pole piece holder having a pole piece insertion hole, a plurality of metal alloy pole pieces which are inserted and fixed in the plurality of pole piece insertion holes, respectively, and for attaching the pole piece holder to the neck portion. A magnet device for a color cathode ray tube, comprising a mounting means.