TWI234391B - Centering magnet - Google Patents

Abstract

In the centering magnet 10a, a groove or a through hole is provided on one side of opposing magnetic poles, and the quantity of resin in the region on the opposite side to the gate hole side of the center where the density of the magnetic powder becomes higher is lessened, thereby the deviation of the magnetizing strength is reduced.

Description

1234391 (1) 发明 Description of the invention [Technical field to which the invention belongs] The present invention relates to a one-pole center position adjustment magnet installed in a deflection range of a cathode ray tube. [Prior art]

In a cathode ray tube of a television receiver or a display device, the electron beam deflected by the deflection yoke can be correctly irradiated to a desired position on the fluorescent surface, and the centering adjustment of the electron beam is performed. The centering adjustment is performed by rotating the adjustment magnet provided at the center position of the ring shape which is biased toward the yoke. The center position adjustment magnet is made of resin mixed with magnetic powder. When using a mold resin to shape the center position of the magnet, unevenness (i.e., deviation) occurs in the density of the magnetic powder.

If a deviation occurs in the density of the magnetic powder when the magnet is adjusted at the center position of the resin molding, the magnetization varies with the density. If there is a deviation in the magnetization, the cross-sectional shape of the electron beam will be deformed, the focusing performance of the image will be deteriorated, and the sharpness will be reduced. A method for reducing the deviation of the magnetization of the magnet in order to reduce the center position is disclosed in Japanese Patent Application Laid-Open No. 2002-75250, but there are still several shortcomings in this direction. [Summary of the Invention] Therefore, an object of the present invention is to provide a central position adjustment that removes deviations in magnetization and reduces the focus performance and sharpness of an image ►4-(2) 1234391 whole magnet, and using the central position Adjust the deflection of the magnet to the yoke. ^ In order to solve the above-mentioned problems, the present invention is to reduce the amount of resin in the area where the density of the magnetic powder on the opposite side of the gate to the center portion is reduced in the center position adjustment magnet, thereby reducing the deviation of magnetization after magnetization. And reduce the focus performance and sharpness of the image. A center position adjusting magnet according to an embodiment of the present invention is provided with a recessed portion or a through hole on one side of the opposing magnetic poles that are required to reduce the dispersion of magnetic powder density during resin molding. [Embodiment] An embodiment of the present invention will be described in detail with reference to the drawings. Fig. 1 is a cross-sectional view showing an example of a CRT projection display device to which the present invention is applied, and schematically shows the overall structure of an optical system. In Fig. 1, the following deflection yoke, speed modulation coil, etc. are omitted. In FIG. 1, a CRT (cathode ray tube) 12 is mounted with a CRT driving circuit board 1 1, and C RT 12 is driven by an image signal supplied from the driving circuit board 11 to display an image thereon. Fluorescent surface. The image displayed on the fluorescent surface of the CRT 12 is incident on the lens 14 via the optical coupling system 13. The optical coupling system 13 is filled with a cooling liquid and absorbs heat generated when the CRT 12 operates. The image incident on the lens 14 is enlarged, and is reflected on the mirror 15 to reach the back of the shield 16. As a result, the image displayed on the fluorescent screen of the CRT 12 is enlarged and displayed on the mask 16, and the user can view the image on the mask 6. (4) 1234391 FIG. 4 is a diagram showing the configuration of the deflection yoke 2; FIG. 4A is a top view; FIG. 4B is a front view; and FIG. 4C is a side view. 2a is the deflection yoke body, 2Hc is the belt and locking screw used to fix the deflection yoke 2 to the tube neck 1 2a of 12; 1 〇 is the center position # adjustment magnet, the center position adjustment magnet 10 is the electron beam For centering adjustment.

The centering adjustment of the electron beam is as shown in Fig. 5. The center position adjustment magnets 10 of the two ring-capped dogs are superimposed and installed on the tube neck of the yoke 2. The center position adjustment magnets are adjusted by rotating them separately. Carried out. Fig. 6 shows the entire center position adjusting magnet 10; Fig. 6 A shows a side view; and Fig. 6 B shows a front view. In this embodiment, the center position adjusting magnet is a two-pole magnetized permanent magnet.

FIG. 7 is a diagram showing a state of centering adjustment. The centering adjustment is performed for each CRT when assembling a projection tube in a manufacturing plant to perform positioning of each RGB image displayed on the shield. In the centering adjustment, a still picture drawn with ~ circles in the center of the portrait is displayed on the shield 16. When the centering adjustment is not adjusted, for example, the circle is displayed at a position deviating from the center of C3, such as an ellipse. As shown in FIG. 5, the rotation angle difference between the two central position adjustment magnets 10 is changed by using the knob portion 20 to make the two central positions adjust the strength or direction of the combined magnetic field of the magnets 10. If the direction of the synthesized magnetic field is not changed but only the intensity is changed, that is, the knob portions 20 a and 20 b are rotated only by the same angle in opposite directions, the circle C is moved in the direction of the arrow & Without changing the rotation angle difference of 0, but rotating the two center position adjustment magnets in the same direction as (5) 1234391, the circle C moves in the direction of arrow b in FIG. 7. The magnetic field directions of the two center position adjustment magnets and iron 10 can overlap the knob portions 20a and 20b exactly, and the combined magnetic field strength becomes the strongest. Then, a circle is displayed at the position farthest from the center, such as circle C2, and the circle Deformation is the greatest. The centering adjustment can be changed by adjusting the rotation position of the knob. Adjust the size and direction of the combined magnetic field of the magnet 10 according to two center positions. 俾 Display circle C at the center of the shield 16. When the centering adjustment is performed correctly, the circle C is displayed at the center of the shield 16 without distortion. With this adjustment, the electron beam is irradiated to the regular position on the fluorescent surface of the CRT. The center position adjusting magnet 10 is formed by flowing a resin mixed with magnetic powder into a mold as shown in Fig. 8. At this time, as shown in Fig. 9, a resin molding gate is provided on one of the rotary adjustment knob portions 20, and the magnetic material powder is mixed into the resin and flows through the gate (the arrow indicates the flow of the resin). In this way, since the center position adjustment magnet 10 has a single gate, it can be resin-formed in two rows at the same time as shown in FIG. 8. Therefore, it is possible to simultaneously form a plurality of metal films, and the manufacturing efficiency is high. After molding with mold resin, the center position adjustment magnet is completed by magnetizing at the two poles. Aluminium-nickel-cobalt alloy system, ferrite magnetic system, and rare-earth system are used to adjust the magnetic material of the magnet 10 at the center position. However, from the viewpoint of magnetic strength, temperature characteristics, price, and productivity, generally, aluminum-nickel-cobalt alloy system By. Compared with the ferrite magnetic system, the magnetic powder of the aluminum-nickel-cobalt alloy system used to adjust the magnet at the center position made of resin is larger in size than the ferrite magnetic system. In the process of (6) 1234391, the inside of the magnet is adjusted at the center position A problem that a deviation in the density of the magnetic powder occurs is caused. As shown in FIG. 9 in detail, the magnetic powder density decreases and decreases at the inlet of the resin, and at the opposite part of the gate, that is, after the inflow of the resin is divided in two directions by the molding die, the magnetic powder is merged. The density of the magnetic powder becomes higher.

When the magnetization magnetic force of the magnet is adjusted at the center position where the deviation of the density of the magnetic material powder occurs in this way, the deviation of the magnetization occurs in accordance with the deviation of the density. As shown in Fig. 10, the magnetic flux density becomes dispersed at the gate side where the magnetic material density is low, and the opposite side of the gate has a high magnetic material density and a high magnetic flux density. As a result, the pole points are biased from the center of the poles to one of the strength concentrations of the magnetic poles. In this way, when the two center position adjustment magnets with the depolarized points are assembled for centering adjustment, the cross-sectional shape of the electron beam is deformed, the focusing performance of the image is deteriorated, and the sharpness of the image is reduced.

Fig. 11 is a center position adjusting magnet 10a showing an embodiment of the present invention; Fig. 11A is a plan view; Fig. 11B is a cross-sectional view taken along the line A-A of Fig. 11A; Fig. 11C is a view showing 11A Figure B-B sectional view. On the opposite side of the gate, adjust the ring shape setting structure of the magnet along the center position at a position from 45 ° to 135 ° from the center line d of the magnetic pole. In the intervals from 45 ° to 85 ° and 95 ° to 135 ° from the center line d between the magnetic poles, the groove bottom surface is sloped, and the depth of the interval from 85 ° to 95 ° is constant. . In addition, the range (angle) of the groove and the depth and width of the groove are adjusted by adjusting the size of the magnet and the molding conditions or materials at the center position.

-9- (7) 1234391 The amount of resin can be adjusted by the shape (size) of the groove, as shown in Figure 12 to achieve the balance of magnetization. That is, the groove is a partial density reduction portion that functions to reduce the variation in the density of the magnetic powder. This groove has the same effect as when the groove is opened in a magnetized current product. Fig. 13 shows a center position adjusting magnet 10b according to another embodiment of the present invention. The center position adjustment magnet 1 Ob serves as a reduction in partial density, and instead of the above-mentioned grooves, by providing holes of a large size, the same amount of magnetization can be obtained as in the above embodiment. The same effect can be obtained if the hole is opened before magnetization or after magnetization. Fig. 14 shows a center position adjusting magnet 10C according to another embodiment of the present invention. The center position adjusting magnet 10C serves as a partial density reduction portion, and a recessed portion is provided on the opposite side of the gate instead of the above-mentioned groove or hole. This concave portion is provided as a convex portion in the mold when resin molding is performed as shown in FIG. 8. Therefore, the center position adjustment magnet 10C is a shape suitable for mass production. As can be seen from FIG. 14, the center position adjusting magnet according to the present invention includes a knob portion 20 and a ring portion 21. The ring portion 21 is divided into two pairs on a straight line d including the center point f of the ring portion. When the N-pole side and the S-pole side are oriented, the volume differs between the N-pole side and the s-pole side. The present invention is naturally applicable to the uniformity of the magnetization amount of a PCM magnet (for center convergence adjustment) used in a color brown tube. [Brief Description of the Drawings] FIG. 1 is a cross-sectional view showing an example of -10- 1234391 (8) of a c R T projection display device to which the present invention is applied. Fig. 2 is a diagram showing the relationship between the lens 14 and the shield of the CRT 12; Fig. 3 is a perspective view showing the structure of a projection device used in the CRT projection type display device as shown in Fig. 1; 4A to 4C are diagrams showing the configuration of the deflection yoke 2. Fig. 5 is a diagram showing two center position adjustment magnets overlapping each other. 6A and 6B are diagrams showing the entire center position adjustment magnet. FIG. 7 is a diagram showing a state of centering adjustment. Fig. 8 is a view showing a state in which the magnet is adjusted by the position of the resin molding center using a mold. Fig. 9 is a view showing a state in which a center position adjusting magnet is injected into a mold; Fig. 10 is a diagram showing the adjustment of the magnet at the center position where the pole-polarization point of the magnetic pole deviates from the center between the poles due to the deviation of the magnetic material powder density. 11A to 11C are diagrams showing a center position adjusting magnet 10a according to an embodiment of the present invention. Fig. 12 is a diagram showing a central position adjustment magnet for achieving a balance of magnetization amounts according to the present invention. Fig. 13 is a diagram showing a central position adjustment magnet 10b according to another embodiment of the present invention. Fig. 14 is a diagram showing a center position adjusting magnet 10b according to another embodiment of the present invention. -11-(9) (9) 1234391 Component comparison table 2: Offset yoke 5, 1 1: CRT drive circuit board 6: Speed modulation circuit board 7: Speed modulation coil 1 〇: Center position adjustment magnet 12: CRT (Cathode ray tube) 1 3: Optical coupling system 1 4: Lens 15: Reflector 16: Shield 20: Rotary adjustment knob part -12-

Claims (1)

1234391 The scope of the patent application is 92 1 22774. The Chinese patent application is amended. The Republic of China was revised on February 24, 2013. 1. A center position adjusting magnet, which belongs to the centering adjustment of the electron beam of a cathode ray tube. The central position adjustment magnet is characterized by: It is formed of a resin containing a magnetic powder and has an opposing magnetic pole. On one of the opposing magnetic poles, a partial density reduction section is provided to reduce the deviation of the magnetic powder density. 2 · The center position adjustment magnet according to item 1 of the scope of the patent application, wherein the partial density reduction portion is a groove provided along the center position adjustment magnet shape. 3. The center position adjusting magnet according to item 1 of the scope of patent application, wherein the reduced partial density portion is a concave portion. 4. The center position adjusting magnet according to item 1 of the scope of the patent application, wherein the reduced partial density portion is a through hole. 5 · The center position adjusting magnet according to item 1 of the scope of patent application, which includes a knob portion and a ring portion, and the straight line including the center point of the ring portion is bisected to the N-pole side of the ring portion and In the S-pole side, the volume is different on the N-pole side and the S-pole side. 6 · —A kind of deflection yoke, which belongs to a deflection yoke used in a cathode ray tube, which is characterized in that the deflection yoke is a two-pole magnetization center position adjustment magnet with an electron beam for centering adjustment; the center position adjustment magnet is a resin reduction 1234391 The partial density reduction portion of the variation in magnetic powder density during molding is provided on one of the opposing magnetic poles. 7. The deflection yoke according to item 6 of the scope of patent application, wherein the upper deflection density reduction portion is a structure provided by adjusting the shape of the magnet along the center position. 8. A deflection yoke, which belongs to a deflection yoke used in a cathode ray tube, #Characteristics: the deflection yoke is a two-pole magnetization center position adjustment magnet for centering adjustment of the electron beam; the center position adjustment magnet is a straight line including a knob portion and a ring portion, and a straight line including the center point of the ring portion; When divided into the N-pole side and the S-pole side facing each other in the ring portion, the volume is different between the N-pole side and the S-pole side.