KR19980014953A - CRT Raster Distortion Correction Device - Google Patents

Abstract

The present invention relates to a cathode ray tube and a raster distortion correcting apparatus for correcting an electron beam scanned and deflected in a structure of a cathode ray tube to compensate for distortion of a raster due to maximum shake of deflection at a peripheral portion of a cathode ray tube.

This apparatus includes a core 22 for focusing a magnetic field in front of a bobbin 21 and a deflection coil 23 forming a horizontal and vertical deflection magnetic field, the deflection yoke assembly comprising: Four pieces 24 having a predetermined magnetic force are arranged at regular intervals on a circumference having a predetermined radius and are spaced apart from the deflection coil 23 at a constant interval.

Accordingly, by appropriately mounting a predetermined piece to the deflection yoke assembly, the deflection of the deflection at the periphery of the cathode ray tube can be minimized to prevent the cathode ray and the raster on the front panel from being distorted into a failure type, Can be simplified.

Description

CRT Raster Distortion Correction Device

The present invention relates to a color cathode-ray tube (or cathode ray tube), and more particularly, to a cathode ray tube which corrects distortion of a raster due to a maximum shake of deflection at the periphery of a cathode ray tube, To a raster distortion correcting apparatus.

In general, a cathode ray tube is a vacuum bulb structure in which a panel and a funnel are bonded. As shown in FIG. 1, a shadow mask 15 and an electron gun assembly And a deflection yoke assembly 13 is mounted to the front of the electron gun assembly 12 from the outside thereof to complete the cathode ray tube assembly 10.

The electron gun assembly 12 is composed of a cathode (not shown) and a plurality of lenses (not shown). The electron beam 14 emitted from the cathode is focused and accelerated by various lens systems, Accelerated and then deflected by the deflection yoke assembly 13 to reach the shadow mask 15.

The electron beam 14 passing through each aperture (or slot) in the shadow mask 15 in which numerous fine holes are formed is scanned on the fluorescent surface formed on the inner surface of the front panel 11 to form a phosphor Thereby forming each pixel corresponding to the aperture.

Due to the structure of the cathode ray tube, when the central portion of the cathode ray tube is the deflection center, the angle of deflection of the electron beam 14 toward the peripheral portion becomes larger. As a result, the electron beam 14 is distorted in a failure mode in which the rubbing of the deflection at the four corners of the cathode ray tube is maximized and the raster indicating the deflection area by the deflection yoke assembly 13 is defective.

Accordingly, it is an object of the present invention to provide a cathode ray tube raster distortion correcting apparatus which is provided with a predetermined means in a deflection yoke assembly to minimize distortion of a deflection at a peripheral portion of a cathode ray tube, have.

1 is an exemplary view showing a color cathode-ray tube in partial cross-section,

2 is a side view showing a deflection yoke assembly according to the present invention,

3 is a cross-sectional view taken along line X-X of FIG. 2;

4 is a state diagram showing a conventional and raster of the present invention in comparison;

Description of the Related Art

10: cathode ray tube assembly, 11: front panel, 12: electron gun assembly,

13: deflection yoke assembly, 14: electron beam, 15: shadow mask,

21: bobbin, 22: core, 23: deflection coil, 24:

25: fastening band, 26: fastening screw, R: raster (conventional), R ': raster (present invention)

In order to achieve the above object, a deflection yoke assembly supporting a core 22 for focusing a magnetic field in front of a bobbin 21 and a deflection coil 23 forming a horizontal / vertical deflection magnetic field, Characterized in that four pieces (24) having a predetermined magnetic force are arranged at regular intervals on a circumference of a predetermined radius at a front surface of the bobbin (21) and a constant gap is maintained between the deflection coil (23) Tube raster distortion correction device.

At this time, the magnetic poles 24 are arranged at symmetrical positions from the vertical and horizontal lines passing through the center of the core 22, and are rotated clockwise and N-S poles are repeated.

Example

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a side view showing a deflection yoke assembly according to the present invention.

The deflection yoke assembly to which the present invention is applied also includes the bobbin 21, the core 22, the deflection coil 23, and the like as main components. This deflection yoke assembly is mounted on the funnel portion at the rear end of the cathode ray tube by the tightening band 25 and the tightening screw 26. [

The deflection coil 23 is constituted by a horizontal coil and a vertical coil, and forms a magnetic field which horizontally and vertically deflects the electron beam 14 (Fig. 1), respectively.

The core 22 typically uses a ferrite material and concentrates the magnetic field generated by the deflection coil 23.

The bobbin 21 serves to separate and support the horizontal coil and the vertical coil, and the tightening band 25 and the tightening screw 26 are attached to the rear end thereof.

At this time, in the present invention, four pieces 24 having a predetermined magnetic force are arranged on the front surface of the bobbin 21 at regular intervals on a circle having a predetermined radius. The pieces 24 do not contact the deflection coil 23 but maintain a constant gap therebetween.

The magnetic piece 24 may be a rod-shaped permanent magnet or an electromagnet.

Figure 3 shows a short view of X-X in Figure 2.

The arrangement of the pieces 24 is shown to be symmetrical with respect to the vertical and horizontal lines passing through the center of the core 22. That is, on the front panel 11 (see FIG. 1) of the cathode ray tube.

The magnetic pole arrangement of the individual pieces 24 is rotated in the clockwise direction in the figure, and the N-S pole is repeated in the view.

The body 24 may be molded at a predetermined position when the bobbin 21 is molded or may be formed to be slightly different from the bobbin 21 by a minute distance on the circumference where the body 24 is provided. Considering the thermal deformation of the bobbin 21 due to the temperature change inside the cathode ray tube, the latter variable fixing method is preferable.

4 is a state diagram showing a conventional and raster of the present invention in comparison with each other.

In the drawing, the raster R is formed when the front panel 11 (see FIG. 1) is viewed. As the angle of deflection toward the periphery of the front panel 11 increases, the electron beam 14 It is possible to observe the raster (R) which is distorted to the failure type by the maximum shake of the deflection at the four corners of the cathode ray tube.

At this time, the magnetic piece 24 disposed around the deflection coil 23 exerts a predetermined magnetic force on the electron beam deflected to the four corners of the cathode ray tube.

The direction of the magnetic field to which the present invention is externally applied for exerting magnetic force in the direction of the arrow in the drawing is determined by Fleming's left-hand rule. Since the direction of the current is the direction toward the inside of the front panel 11 and the direction of the magnetic field is the direction of N → S, the direction of the magnetic force is formed in the direction toward the center as shown by an arrow.

Therefore, at the four corners of the cathode ray tube, the electron beam is compressed to the center and the distorted phenomenon as raster (R ') indicated by the dotted line disappears.

On the other hand, the cathode ray tube raster distortion correcting apparatus of the present invention may be used in combination with the conventional correcting circuit means for preventing the raster failure type distortion, and in some cases, such correction circuit may be omitted.

In the cathode ray tube and distortion correcting apparatus according to the present invention, the deflection yoke assembly is suitably fitted with a predetermined piece, thereby minimizing deflection at the periphery of the cathode ray tube, so that the cathode ray and the raster on the front panel are distorted There is an effect to prevent.

In addition, the correction means does not require a high degree of accuracy in terms of the shape and distribution of the vertical and horizontal oriented coils, thereby simplifying the deflection coil.

Although the present invention has been shown and described with respect to certain preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as set forth in the following claims It will be readily apparent to those skilled in the art.

Claims (2)

A deflection yoke assembly supporting a core (22) for magnetic field focusing and a deflection coil (23) forming a horizontal / vertical deflection magnetic field in front of a bobbin (21) Characterized in that four pieces (24) having a predetermined magnetic force are arranged on the front surface of the bobbin (21) at regular intervals on a circumference having a predetermined radius, and a constant gap is maintained between the deflection coil (23) Tube raster distortion correction device. [2] The apparatus according to claim 1, wherein the body pieces (24) are disposed at points mutually symmetric with respect to a vertical line and a horizontal line passing through the center of the core (22) A cathode ray tube raster distortion correcting device.