JP2746931B2 - 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.

[Conventional technology]

A color CRT is provided with a static convergence and a magnet device for adjusting the brightness at the center of the screen in order to absorb component errors 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 operator, 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. Pat.No. 4,138,628, U.S. Pat.No. 4,159,456, U.S. Pat. The barium ferrite sheet is wound and fixed using a tie band or the like, and a plurality of portions of the barium ferrite sheet are magnetized at a controlled predetermined intensity, and multipole magnetized so as to generate a magnetic field for achieving a desired correction. Things have been suggested.

[Problems to be solved by the invention]

In the above prior art, since a barium ferrite sheet is used as a magnet member for magnetization, the temperature characteristic of the magnetization is as large as about -0.2% / ° C., and the characteristic changes due to a rise in the temperature of the neck portion and the cabinet. There is a problem that the convergence drift is large and it is difficult to maintain high precision required for display applications.

In order to solve such a problem, the applicant of the present application arranges a plurality of pole pieces made of a metal alloy to be magnetized around a neck tube, and uses a magnetic field created by magnetizing the plurality of pole pieces to form a stator. A magnetic device for adjusting the topic convergence and the brightness is pending. This will be described in more detail.

Since conventionally used barium ferrite has a large temperature drift, it is necessary to use a rare-earth cobalt or Fe-Cr-Co-based magnet material having excellent temperature characteristics for display. However, this kind of magnet wood
Unlike conventional magnet materials, it is difficult to obtain a flexible sheet-like material, and it is difficult to take an integrated structure. Even when integrated, it is difficult to obtain a magnetic field distribution necessary for adjustment because of the high magnetic permeability of the material. For these reasons, it is necessary to arrange a plurality of independent magnetic pole pieces around the neck portion, adjust the amount of magnetization, and adjust the static convergence and the pyramid characteristics.

In order to dispose a plurality of such independent pole pieces outside the neck portion, the plurality of pole pieces are circumferentially fixed to a ring-shaped magnetic pole holder, and the magnetic pole holder is fixed to another magnetic ring for fine adjustment. In the same manner as described above, it is fixed to a holder fixed to the outer diameter portion of the net portion or to a net portion attachment such as a net fixing portion of the deflection yoke. However, when the magnetic pole holder is inserted and fixed to the outer diameter of the neck mounting body, the magnetic pole pieces are arranged in a direction away from the center of the network, and the size of the magnetic pole pieces required for the same beam position adjustment is reduced. The problem of growing larger arises.

It is also conceivable that a plurality of magnetic pole pieces are directly and integrally molded with the above-mentioned neck portion mounting body. However, this is disadvantageous in terms of manufacturing cost, and there is a problem with changing the magnetic pole characteristics, especially in changing the magnetic pole characteristics.

SUMMARY OF THE INVENTION An object of the present invention is to provide a magnet device for a color cathode-ray tube in which a plurality of pole pieces can be brought close to a tube wall of a network.

[Means for solving the problem]

In order to achieve the above object, the present invention provides a magnetic pole in which an inner peripheral portion is fitted into a neck portion of a color cathode-ray tube, and a plurality of magnetized magnetic pole pieces for adjusting static convergence and purity are circumferentially attached. A holder, a neck ring having an inner peripheral portion fitted into the neck portion, a magnet ring mounted on the outer peripheral portion, and a neck portion mounting body at one end of which the magnetic pole holder is elastically engaged; A groove is provided between the mounting portions of the pole pieces, and the protrusion of the neck mounting body is elastically engaged with the groove, and the protrusion of the neck mounting body at the mounting portion of the plurality of magnetic pole pieces is determined by the depth of the groove. Is formed thin or the formation of the protrusion is omitted.

[Action]

A groove is provided between the attachment portions of the plurality of pole pieces on the inner periphery of the pole holder, and the protrusion of the neck attachment body is elastically engaged with the groove, so that the attachment portion of the plurality of pole pieces is provided. That is, it becomes possible to bring a plurality of pole pieces closer to the neck tube wall than the depth of the groove.

In addition, since the magnetic pole holder is detachably attached to the neck attachment body, it is easy to cope with a change due to a pipe type and a design change. Furthermore, when another magnet ring or the like for fine adjustment (for re-adjustment) is attached to the neck portion mounting body, the magnet ring or the like can be easily inserted.

Also, the elastic engagement between the groove of the magnetic pole holder and the protrusion of the neck part mounting body is performed by the engaging part provided in the groove part and the claw part provided at the tip of the protrusion part. Elastic engagement with the magnetic pole holder and the neck mounting body after the elastic engagement are accurately maintained.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. As shown in FIG. 9, the color cathode ray tube 1 is equipped with a deflection yoke 2 and a magnet device 3 for static convergence and for adjusting the brightness.
Here, since the deflection yoke 2 is not directly related to the gist of the present invention, its detailed description is omitted.

The magnet device 3 has a structure as shown in FIGS. That is, the tubular neck portion mounting body 4 made of an electrical insulating material such as plastic and attached to the neck portion 1a of the color cathode-ray tube 1 has a collar portion 4a.
A fixing locking ring 5, a spacer 6A, a fine adjustment magnetic ring 7 and a spacer 6B are mounted on the deflection yoke 2 side from the flange 4a. Here, the locking ring 5 and the magnet ring 7 are rotatable. But,
The spacers 6A and 6B are formed with a convex portion on the spacers 6A and 6B and a concave portion on the neck portion mounting body 4 in order to prevent the magnet ring 7 from rotating together when the locking ring 5 is tightened. There is, but cannot rotate.
A plurality of magnetic pole pieces 8A to 8H, which are magnetized to adjust the static convergence and the brightness, are circumferentially embedded on the outer periphery of the tip end portion of the network mounting member 4 from an electric insulating material such as plastic. The magnetic pole holder 9 is detachably mounted. The pole pieces 8A to 8H are made of rare earth cobalt, Fe-Cr-Co alloy, or the like, and the temperature change of the magnetic flux density after magnetization is -0.03% / ° C, which is about 1/10 of that used conventionally. And small. For this reason, the network
Even if the temperature of 1a rises, the temperature change of the magnetic flux density is small, and the change of the static convergence and the adjustment amount of the pirity can be practically ignored.

The structure for mounting the magnetic pole holder 9 to the neck mounting body 4 is as follows. The magnetic pole holder 9 has
As shown in FIGS. 2, 3, and 7, a groove 9a is formed between the mounting portions of the plurality of pole pieces 8a to 8h. As shown in FIGS. 2 to 6, a plurality of protrusions 4b each having a claw portion 4b 'at the tip and a plurality of protrusions 4b are provided on both sides of each protrusion 4b. Slit 4d and a plurality of insulating protrusions 4c formed between the slits 4d and thinner than the protrusions 4b. in this case,
The plurality of protrusions 4b are provided at positions corresponding to the grooves 9a between the attachment portions of the plurality of pole pieces 8A to 8H, respectively, and the plurality of insulating protrusions are provided.
4c is provided at a position corresponding to each of the attachment portions of the plurality of pole pieces 8A to 8H. Further, the magnetic pole holder 9 is provided in each groove portion.
An engagement portion 9b that engages with the claw portion 4b 'is provided in 9A.
Therefore, when the magnetic pole holder 9 is pushed into one end of the neck mounting body 4 and mounted, the claw 4b 'of the projection 4b of the neck mounting body 4 inserted into the groove 9a of the magnetic pole holder 9 is formed by the groove.
When the claw portion 4b 'rides over the engagement portion 9b in a state where the claw portion 4b' comes into contact with the engagement portion 9b in the 9a and the projection portion 4b is bent, the deflection of the projection portion 4b is eliminated by elasticity, and the claw portion 4b ' The magnetic pole holder 9 is attached to the neck attachment body 4 by engaging with the engagement portion 9b.

Thus, the plurality of pole pieces 8A to 8H of the pole holder 9 are
The protrusions 4b of the neck mounting member 4 are engaged with the grooves 9 between the mounting portions of the magnetic head, and the magnetic pole holder 9 is mounted on the neck mounting body 4, and the plurality of magnetic pole pieces 8A to 8H are mounted. The plurality of insulating protrusions 4c of the neck attachment 4 corresponding to the attachment portions do not contribute to mounting the magnetic pole holder 9 on the neck attachment 4. Accordingly, as shown in FIGS. 1, 2 and 4, the outer diameter dψ of the insulating protrusion 4c can be formed smaller than the outer diameter Dψ of the protrusion 4b.
It is also possible to omit the provision of 4c, and it is possible to form the outer diameter dψ of the insulating protrusion 4c smaller than the outer diameter Dψ of the protrusion 4b, and to omit the installation of the insulating protrusion 4c. A plurality of pole pieces 8A to 8H can be arranged close to the tube wall of the neck portion 1a, so that static convergence and purity with high sensitivity can be adjusted.

As shown in FIG. 1, a fastening tongue piece 4e is provided on the side of the collar part 4a of the neck part mounting body 4 opposite to the magnetic pole holder 9. The tightening tongue 4e is a tightening band 10 and tightening bolt
In order to fix the entire neck portion mounting body 4 to the neck portion 1a by means of 11, a slit 4f is provided to have elasticity.

By the way, in order to integrally form the neck portion mounting body 4 having such a shape, it is necessary to insert a mold pin for forming the claw portion 4b from the fastening tongue piece portion 4e side. In view of this, the flange portion 4a is provided with a mold pin insertion hole 4g (see FIG. 4) at an axial portion corresponding to the claw portion 4b.
Further, a fastening tongue piece 4e is provided at an axial extension of the claw 4b. When the tongue piece 4e is provided on the extension of the claw 4b in this manner, the network attachment 4 can be firmly fixed to the network 1a.

On the other hand, in order to firmly engage and attach the magnetic pole holder 9 to the neck mounting body 4, the grooves 9a and the engaging portions 9b may be provided evenly on the inner periphery of the magnetic pole holder 9, and in this embodiment, , Eight magnetic pole pieces 8A to 8H are evenly arranged circumferentially, and a groove 9a and an engaging part 9b are provided between the eight magnetic pole pieces 8A to 8H, respectively.

Next, the magnetization of the pole pieces 8A to 8H will be described. As shown in FIG. 9, after the deflection yoke 2 and the magnet device 3 are mounted on the cathode ray tube 1, the magnetic pole pieces 8A to 8H are magnetized in accordance with the necessary correction amounts, thereby adjusting the static convergence and the pirity. Do. This pole piece 8A ~ 8H
Will be described with reference to FIG. FIG. 9A shows a case where both side beams are adjusted in the opposite directions in the vertical direction. This adjustment is performed by the pole pieces 8A, 8C, 8E, and 8G. FIG.
Is to adjust the side beam in the opposite direction from side to side.
This adjustment is performed by the pole pieces 8B, 8D, 8F, and 8H. 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.
Perform by 8H. 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.

In the above embodiment, the case where eight magnetic pole pieces 8A to 8H are used has been described.

By the way, the magnetic pole pieces 8A to 8H having a small temperature change in magnetic flux density are expensive because rare metals are used, but the magnetic pole pieces 8A to 8H are expensive.
8H requires only a small volume and requires only a small amount of use, so it can be realized at low cost. In this embodiment, the pole pieces 8A to 8H are 3.5 mm
φ × 7mm. Further, these pole pieces 8A to 8H can be easily manufactured by cutting from a wire rod or the like, and there is no problem in manufacturing when forming into an annular shape or a sheet shape.

As is clear from the above description, the engaging portion 9b provided in the groove 9 between the mounting portions of the plurality of magnetic pole pieces 8A to 8H of the magnetic pole holder 9 has the claw portions of the projecting portion 4b of the neck portion mounting body 4. 4b 'are formed so as to engage with each other, so that the outer diameter d 絶 縁 of the insulating protrusion 4c can be formed smaller than the outer diameter Dψ of the protrusion 4b. In some cases, the insulating protrusion 4c is provided. Can be omitted, so that the pole pieces 8A to 8H can be arranged very close to the tube wall of the neck portion 1a. As much as the pole pieces 8A to 8H can be arranged close to the network portion 1a in this manner, a large adjustment amount of about 30% can be obtained with the same pole pieces 8A to 8H, so that the pole pieces 8A to 8H having a small temperature coefficient can be obtained. Can be reduced in size, and magnetization can be facilitated.

Further, since the magnetic pole holder 9 is detachably attached to the neck attachment body 4, it is easy to cope with a change due to a pipe type or a design change. Further, when the fine adjustment magnetic ring 6 or the like is attached to the neck portion mounting body 4, the magnetic ring 6 can be easily inserted.

Further, the elastic engagement between the magnetic pole holder 9 and the neck mounting body 4 is performed by an engaging portion provided in the groove 9 on the inner periphery of the magnetic pole holder 9.
9b and a claw portion of a protruding portion 4b provided at one end of the neck portion mounting body 4.
Since the magnetic pole holder 9 is engaged with the neck part 4, the magnetic pole holder 9 can be easily engaged with the neck part mounting body 4.

〔The invention's effect〕

As described above, according to the first aspect of the present invention, a groove is provided between the attachment portions of the plurality of pole pieces on the inner peripheral portion of the pole holder, and the protrusion of the neck attachment body is elastically engaged with the groove. Let
The plurality of pole pieces of the pole holder are attached to the neck portion by forming the protrusions of the neck attachment body at the attachment portions of the plurality of pole pieces to be thinner than the depth of the grooves or omitting the formation of the protrusions. It can be placed close to the tube wall,
There is an effect that a plurality of magnetic pole pieces can be small and can be easily magnetized.

According to the second aspect of the present invention, the elastic engagement between the magnetic pole holder and one end of the neck portion attaching body is made detachable, so that it is possible to easily cope with a change in the type of the color cathode-ray tube. In addition to this, there is an effect that a fine adjustment magnet ring or the like can be easily attached.

According to the third aspect of the present invention, the tip of the protrusion of the neck attachment body has a claw that elastically engages with an engagement portion provided in the groove of the magnetic pole holder, and both sides of the protrusion. The magnetic pole holder is easily elastically engaged with one end of the neck attachment body by forming a slit along the projection and providing elasticity to the claw of the projection that elastically engages with the engagement part of the groove. In addition, there is an effect that the magnetic pole holder can be easily engaged and attached to the neck attachment body while maintaining the mutual position.

[Brief description of the drawings]

FIG. 1 is a half sectional view of a magnet device according to an embodiment of the present invention, FIG. 2 is a left side view of FIG. 1, and FIG. 3 is A of FIG.
FIG. 4 is a sectional view taken along the line A, FIG.
FIG. 6 is a side view of FIG. 4, FIG. 6 is a partial view of an arrow B in FIG. 4, FIG. 7 is a front view of a magnetic pole holder, and FIG.
(B) and (c) are explanatory views showing the relationship between the magnetized state of the pole pieces and the movement of the electron beam. FIG. 9 is a side view of the magnet device shown in FIG. 1 attached to a color cathode ray tube. DESCRIPTION OF SYMBOLS 1 ... Color cathode ray tube, 1a ... Net part, 3 ... Magnetic device, 4 ... Net part mounting body, 4b ... Projection part, 4b '... Claw part, 4c ... Insulation projection part,
4d …… Slit, 8A ～ 8H …… Pole piece, 9 …… Pole holder, 9a …… Groove,
9b: engagement part.

Claims (3)

(57) [Claims] 1. A magnetic pole holder in which an inner peripheral portion is fitted into a neck portion of a color cathode ray tube and a plurality of magnetized magnetic pole pieces for adjusting static convergence and purity are circumferentially mounted on the neck portion. A magnet ring is attached to the outer peripheral portion while the inner peripheral portion is fitted therein, and a neck portion attachment body at one end of which the magnetic pole holder is elastically engaged is provided. A groove is provided between the attachment portions, the protrusion of the neck attachment body is elastically engaged with the groove, and the projection of the neck attachment body at the attachment portion of the plurality of pole pieces is formed at a depth of the groove. A color cathode ray tube magnet device characterized in that it is formed thinner than the above or the formation of the projection is omitted. 2. The color cathode ray tube magnet device according to claim 1, wherein the elastic engagement between the magnetic pole holder and one end of the neck attachment body is detachable. 3. The neck attachment body has a claw at an end of the protruding portion for elastically engaging with an engaging portion provided in a groove of the magnetic pole holder, and the protruding portion is provided on both sides of the protruding portion. 2. The color cathode ray tube magnet device according to claim 1, wherein a slit is formed along the portion, and elasticity is imparted to the claw portion of the protruding portion which elastically engages with the engaging portion of the groove portion.