JPH10210491A - Degaussing device for cathode-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a CRT(cathode-ray tube) degaussing device which can place an object to be demagnetized within a loop of a demagnetizing coil of an intensive magnetic field by defining the rising angle in a specific range at the side of the degaussing coil. SOLUTION: A front side 2c of a degaussing coil 2, which cover the upper and lower surfaces of a CRT 5 of this degaussing device protrudes toward a panel surface 5a from a bezel attachment tool 6. Then an aperture grill 7 is located within a loop formed by the coil 2. Here, the rising angle α (set between a virtual plane 5b of the surface 5a of the CRT 2 and the coil 2) is set at 55 to 90 degrees at both sides 2d1 and 2d2 of the coil 2 respectively. As a result, more of the grill 7 can be included in the loop of the coil 2, and accordingly the demagnetization efficiency is improved. The angle α can be defined on the basis of the plane 5b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a degaussing apparatus for a cathode ray tube, and more particularly to a degaussing apparatus for degaussing a metal part of a cathode ray tube magnetized by geomagnetism or the like.

[0002]

2. Description of the Related Art Conventionally, an aperture grill, a shadow mask, a frame and a shield disposed inside a cathode ray tube are made of a magnetic material, and are magnetized by geomagnetism or the like. In particular, when the aperture grill is magnetized, the direction of the beam is changed when the electron beam passes between the slits of the aperture grill due to the influence of the magnetic field, causing mislanding. Therefore, a degaussing coil is placed around the cathode ray tube, and a degaussing current flows through the coil to degauss the aperture grill and the like. This device is configured to automatically degauss each time the television receiver is turned on.

The demagnetizing current is, for example, as shown in FIG.
Generated by the degaussing current generation circuit. The degaussing current generating circuit is constituted by connecting a degaussing coil 2, a positive temperature characteristic resistance element 3, a switch 4 and the like in series to an AC power supply 1, and when the switch 4 is turned on in conjunction with a power switch of the television receiver, the AC current is generated. Flows through the degaussing coil 2 and the positive temperature characteristic resistance element 3,
A current that decays with time flows through the degaussing coil 2.

The degaussing coil 2 is formed with a loop wound by several tens of turns. As shown in FIGS. 4 and 5, a pair of degaussing coils are arranged above and below the cathode ray tube 5 to constitute a degaussing device. doing. The upper degaussing coil 2a and the lower degaussing coil 2b have the current flowing in their loops in the same direction, and the magnetic field formed by this is in the vertical direction of the cathode ray tube 5.

However, in the conventional degaussing device, the front side 2c of the degaussing coil 2 did not reach the front surface of the cathode ray tube 5, but only reached the front of the bezel mounting bracket 6. This was because the bezel mounting bracket 6 hindered the mounting.

However, as shown in FIG. 4, an aperture grille 7 requiring the most degaussing is located in front of the bezel mounting bracket 6, and its position is outside the loop of the degaussing coil 2. Since the magnetic field generated by the degaussing coil 2 is strong in the loop, it is desirable to place the object to be degaussed in the loop.

[0007]

Accordingly, an object of the present invention is to provide a degaussing apparatus for a cathode ray tube which can position an object requiring degaussing in a loop of a degaussing coil having a strong magnetic field. That is.

[0008]

According to a first aspect of the present invention, there is provided a degaussing apparatus for a cathode ray tube, wherein each front side of a pair of degaussing coils protrudes from a bezel mounting bracket toward a panel surface. In the cathode ray tube degaussing device, which is disposed above and below the cathode ray tube so that the member requiring the most degaussing is located in the loop formed by the degaussing coil, the rising angle of the side of the degaussing coil (the panel of the cathode ray tube) The angle between the virtual plane of the surface and the degaussing coil) is set to 55 ° to 90 ° to improve the degaussing effect.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a degaussing apparatus according to the present invention will be described below with reference to FIGS.
In the degaussing apparatus of the present invention, the front side 2c of the degaussing coil 2 disposed on the upper and lower surfaces of the cathode ray tube 5 is moved from the bezel mounting bracket 6 to the panel surface 5.
It is configured to protrude to the a side. And degaussing coil 2
The aperture grill 7 is positioned in the loop constituted by the above. In this case, in particular, the sides 2d1, 2d of the degaussing coil 2
The rising angle α of d2 (the angle formed by the virtual plane 5b of the panel surface of the cathode ray tube and the degaussing coil) was 55 to 90 degrees.

As a result, almost the entire aperture grille 7 can be put in the loop of the degaussing coil 2 and the degaussing effect can be improved. The sides 2d1, 2d of the degaussing coil 2
The rising angle α of d2 is the virtual plane 5b of the panel surface 5a.
Can be defined as an angle based on

In the above-described embodiment, an example of a cathode ray tube of the Trinitron (trademark of Sony Corporation) system has been described. However, the present invention can be applied to a cathode ray tube of a shadow mask system. In that case, the member that needs to be demagnetized most is a shadow mask.

[0012]

According to the degaussing apparatus for a cathode ray tube of the present invention,
Almost the entire member that requires the most degaussing, such as an aperture grill and a shadow mask, can be put in the loop of the degaussing coil, and the degaussing effect can be improved.

[Brief description of the drawings]

FIG. 1 is a perspective view of a degaussing device of the present invention.

FIG. 2 is a plan view of the degaussing device of the present invention.

FIG. 3 is a diagram showing a demagnetizing current generation circuit.

FIG. 4 is a plan view of a conventional degaussing device.

FIG. 5 is a rear side view of a conventional degaussing device.

[Explanation of symbols]

1: AC power supply, 2: degaussing coil, 2a: upper degaussing coil, 2b: lower degaussing coil, 2c: front side, 2d1, 2d
2 ... side edge, 3 ... positive temperature characteristic resistance element, 4 ... switch, 5
... Cathode tube, 5a ... Panel surface, 5b ... Virtual plane, 6 ... Bezel mounting bracket, 7 ... Aperture grill

Claims (1)

[Claims] 1. A pair of degaussing coils are disposed above and below a cathode ray tube such that respective front sides of the degaussing coils protrude from a bezel mounting bracket toward a panel surface, and a member requiring the most degaussing is located in a loop formed by the degaussing coils. In the cathode ray tube degaussing apparatus, the rising angle of the side of the degaussing coil is set to 55 degrees to 90 degrees.
A degaussing device for a cathode ray tube, characterized in that: