JP2003070013A - Earth magnetism correction device and cathode-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive earth magnetism correction device with high accuracy, capable of correcting the effect on a CRT by earth magnetism. SOLUTION: The device has a structure, in which an earth magnetism correction coil is an approximately rectangular, and the center portions of right and left sides thereof are curved inwardly toward the rectangle so as to be close to a reflection yoke.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a geomagnetism correction device capable of correcting a deviation of an electron beam due to geomagnetism in a cathode ray tube and a cathode ray tube equipped with the same.

[0002]

2. Description of the Related Art A color cathode ray tube, as shown in FIG.
A fluorescent surface 12 is formed on the inner surface of the panel surface 11 of the tubular body 10, and a color selection electrode 13 called a shadow mask is arranged facing the fluorescent surface. The neck portion 16 of the tube body 10
Electrons E emitted from the electron gun 14 installed at the position are deflected by the deflection yoke 15 to scan the predetermined fluorescent screen 12.

However, before the electron beam E emitted from the electron gun 14 reaches the fluorescent screen 12, a phenomenon occurs in which the electron beam E deviates from a predetermined orbit due to the influence of the geomagnetic field in the north-south direction. Due to the influence of the magnetic field due to the earth's magnetism, raster rotation in which the entire screen rotates and becomes slanted on the screen and mislanding in which the electron beam deviates from the center of the phosphor stripe occur.

In order to suppress the influence of the earth's magnetism, a magnetic shield is installed inside the pipe body 10. In addition, as shown in FIG.
Circular raster rotation correction coil 1 around
7 is arranged and this raster rotation correction coil 1
By applying a current to 7 to generate a magnetic field in the direction of canceling the geomagnetism near the deflection yoke, the raster rotation due to the deviation of the electron beam caused by the geomagnetism is corrected, and further, the rectangular surface is surrounded so as to surround the rear surface of the tubular body 10. A geomagnetic correction coil 18 having a shape is attached, and a current is passed through the geomagnetic correction coil 18 to generate a magnetic field in a direction of canceling the geomagnetism near the screen of the tubular body 10 to correct mislanding due to deviation of an electron beam caused by geomagnetism. is doing.

[0005]

In recent years, more accurate geomagnetic correction has been required due to the flattened screen, large size, and high deflection angle of the color cathode ray tube.

However, in the case of the conventional geomagnetic correction device as shown in FIG. 7, since the magnetic field generated by the raster rotation correction coil and the magnetic field generated by the geomagnetic correction coil for performing mislanding correction affect each other,
Accurate correction is difficult, and raster rotation and mislanding due to geomagnetism cannot be corrected at the same time.

[0007]

In order to achieve the above object, a geomagnetism correction device according to claim 1 of the present invention comprises a geomagnetism correction coil and a degaussing coil, and the geomagnetism correction coil has a substantially rectangular shape, The structure is characterized in that the central portions of the left and right sides are curved toward the inside of the rectangle to approach the deflection yoke.

A geomagnetism correction device according to claim 2 of the present invention comprises a geomagnetism correction circuit and a geomagnetism correction coil,
It is characterized in that the geomagnetism correction coil has a substantially rectangular shape, and the central portions of the left and right sides thereof are curved toward the inside of the rectangular shape so as to approach the deflection yoke.

In the geomagnetism correction device according to the third aspect of the present invention, the geomagnetism correction coil has a substantially rectangular shape, and the central portions of the left and right sides of the geomagnetism correction coil are curved toward the inside of the rectangle to approach the deflection yoke. It is characterized by having a structure.

Further, a cathode ray tube according to a fourth aspect of the present invention comprises a geomagnetism correction coil and a degaussing coil, the geomagnetism correction coil is substantially rectangular, and the central portions of the left and right sides thereof are directed to the inside of the rectangle. It is characterized by comprising a geomagnetism correction device having a structure in which the magnetic field is curved toward the deflection yoke to approach the deflection yoke.

A cathode ray tube according to a fifth aspect of the present invention includes a geomagnetism correction circuit and a geomagnetism correction coil, wherein the geomagnetism correction coil has a substantially rectangular shape, and the center portions of the left and right sides thereof are inside the rectangle. It is characterized by comprising a geomagnetism correction device having a structure in which the magnetic field is curved toward the deflection yoke and is brought close to the deflection yoke.

In the cathode ray tube according to claim 6 of the present invention, the geomagnetism correction coil has a substantially rectangular shape, and the central portions of the left and right sides thereof are curved toward the inside of the rectangle so as to approach the deflection yoke. It is characterized by including the geomagnetic correction device.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be specifically described below with reference to the drawings. 1 is a front view of a geomagnetic correction coil that constitutes a geomagnetic correction device according to a first embodiment of the present invention. Figure 2 shows a CRT (color cathode ray tube)
The perspective view of the state where the geomagnetic correction coil is attached is shown in FIG.
In FIG. 2, reference numeral 0 is a CRT (color cathode ray tube), 1 is a geomagnetism correction coil, 2 is a deflection yoke (DY), 3 is a vertical split type degaussing coil and a tape for fixing the geomagnetism correction coil,
Reference numeral 5 denotes a degaussing coil above the upper and lower split type degaussing coils, and 6 denotes a degaussing coil below the upper and lower split type degaussing coils. In this case, as an example, the screen size is 16: 9 and the deflection angle is 120.
32 inch CRT0 with vertical degaussing coil 5,
6 and the geomagnetic correction coil 1 are installed.

The geomagnetic correction coil 1 has a substantially rectangular shape,
It has a structure in which the central portions of the left and right sides are curved toward the inside of the rectangle so as to approach the deflection yoke (DY).
Further, as shown in FIG. 2, the upper and lower sides of the substantially rectangular shape of the geomagnetic correction coil 1 are installed on the upper and lower surfaces of the CRT (color cathode ray tube) 0, respectively, and the geomagnetic correction coil 1 is placed on the rear surface of the CRT (color cathode ray tube) 0. It is arranged along the line. Then, the central portions of the left and right sides of the geomagnetism correction coil 1 are curved toward the inside of the rectangle, and at four positions which are close to the deflection yoke (DY), the decoupling coil of the upper and lower split type is fixed at four positions by using the fixing tape 3. It is fixed to 5 and 6. Further, in the geomagnetism correction device shown in FIG.
A geomagnetism correction circuit for generating DC currents I and I2 is connected.

In the above configuration, when no current is flowing through the geomagnetic correction circuit 19, if the CRT tube surface is directed northward or southward of the geomagnetism, as shown in FIG.
The raster position on the screen moves or raster rotates (rotates) like the dimension A. At the same time, as shown in FIG. 5, at the positions of the upper part 21 and the lower part 22 of the CRT screen, a north magnetic field and a south magnetic field (tube axis direction magnetic field) cause mislanding by about +0.5 to -0.5 gauss, and It becomes uneven.

In particular, a large size, high deflection angle CRT,
Alternatively, the flattening of the screen has made the angle of incidence of the electron beam on the phosphor steeper, so that the influence of geomagnetism has become greater.

At the upper end and the lower end of the CRT screen, the electron beam is affected by the magnetic field in the tube axial direction and deviates from the center of the regular R, G, B phosphor stripes or irradiates adjacent phosphors. Cause color irregularity. At the same time, the electron beam near the deflection yoke is affected by the geomagnetism in the tube axis direction, causing the entire screen to rotate on the screen and cause a diagonal raster rotation.

The shadow mask of the CRT, the IMS, the bimetal fixing the shadow mask, and the demagnetization alone do not solve the color unevenness due to mislanding and the raster rotation. In order to solve this, a magnetic field in the tube axis direction is applied to the geomagnetic field correction circuit 20 of FIG.
It is sufficient to pass the DC current of to cancel the geomagnetism in the tube axis direction. That is, the operation may be performed so that the magnetic field formed by the geomagnetism correction coil 19 and the tube-axis direction geomagnetism become the same. As a result, it is possible to prevent color unevenness due to the raster rotation shown in FIG. 4 and mislanding in the upper screen portion 21 and the lower screen portion 22 of FIG.

The CRT mounting position of the geomagnetic correction coil 1 is important for highly accurate and efficient geomagnetic correction. In the geomagnetism correction apparatus of the present invention, the upper and lower sides of the general rectangle of the geomagnetism correction coil, which are symmetrical in the vertical and horizontal directions, are arranged above and below the CRT, respectively. By adjusting the strength of the correction magnetic field that the geomagnetic correction coil affects the CRT, and by adjusting the distribution of the magnetic field generated by the geomagnetic correction coil according to the lateral lengths of the upper and lower sides,
The unevenness of color due to mislanding caused by the influence of the geomagnetic field in the tube axis direction is corrected by generating a magnetic field in the direction opposite to the magnetic field in which the axial magnetic field in the tube axis direction affects the landing and the magnetic field having the same distribution is generated. ing.

At the same time, the central portions of the left and right sides of the general rectangular shape of the geomagnetic correction coil are curved inward of the general rectangular shape so as to approach the deflection yoke (DY), so that the geomagnetism in the tube axis direction is reversed near the deflection yoke. Raster rotation is corrected by generating a directional correction magnetic field. The curved portion of the geomagnetic correction coil is fixed to the degaussing coil with a fixing tape 3.

Here, the magnitude of the raster rotation correction amount is adjusted according to the degree to which the central portions of the left and right sides of the general magnetism correction coil are curved inward of the general rectangle. Since the magnetic field generated by the side of has almost no effect on the landing, there is almost no effect on the landing correction by bending the central part of the left and right sides of the approximate rectangle of the geomagnetic correction coil to the inside of the approximate rectangle. Absent.

With the above structure, the raster rotation shown in FIGS. 4 and 5 and the color unevenness due to mislanding can be corrected with high accuracy by one geomagnetic correction coil.

[0023]

As described above, the cathode ray tube using the geomagnetism compensating device of the present invention has a flat CRT on the screen, a high deflection angle, and a large CRT, and has a magnetic field facing south and north (axial direction of the CRT tube). The raster rotation of the CRT screen and the color irregularity of the screen due to mislanding can be corrected by one geomagnetic correction coil, resulting in low cost. In addition, magnetic correction in the south and north directions becomes extremely easy, and color unevenness due to raster rotation and mislanding is prevented.

[Brief description of drawings]

FIG. 1 is a diagram showing a form of a geomagnetic correction coil according to the present invention.

FIG. 2 is a perspective view showing an example of a geomagnetism correction device according to the present invention.

FIG. 3 is a configuration diagram showing an example of a geomagnetism correction device according to the present invention.

[Fig. 4] Illustration of raster rotation of the CRT screen in the geomagnetic southward and northward directions

[Fig. 5] An illustration of uneven color on the CRT screen facing south and north of the earth's magnetism.

FIG. 6 is an explanatory diagram showing an example of a general configuration of a cathode ray tube.

FIG. 7 is a perspective view showing an example of a conventional geomagnetic correction coil.

[Explanation of symbols]

0 CRT with 16: 9 screen size 1 Geomagnetic correction coil 2 Deflection yoke (DY) 3 fixing tape 5 degaussing coil 6 degaussing coil 10 tubes 11 panel side 12 Fluorescent screen 13-color selection electrode 14 electron gun 15 Deflection yoke 16 neck 17 Raster rotation correction coil 18 Geomagnetic correction coil 19 Geomagnetic correction coil 20 Geomagnetic correction circuit 21 Top of screen 22 Bottom of screen

Claims (6)

[Claims] 1. A structure including a geomagnetism correction coil and a degaussing coil, wherein the geomagnetism correction coil has a substantially rectangular shape, and central portions of the left and right sides of the geomagnetism correction coil are curved toward the inside of the rectangle to approach a deflection yoke. A geomagnetism correction device characterized in that 2. A geomagnetism correction circuit and a geomagnetism correction coil are provided, wherein the geomagnetism correction coil has a substantially rectangular shape, and central portions of the left and right sides of the geomagnetism correction coil are curved toward the inside of the rectangle so as to approach the deflection yoke. Geomagnetic correction device characterized by having a structure. 3. The geomagnetic correction coil has a substantially rectangular shape,
A geomagnetism correction device having a structure in which the central portions of the left and right sides are curved toward the inside of the rectangle to approach the deflection yoke. 4. A structure comprising a geomagnetism correction coil and a degaussing coil, wherein the geomagnetism correction coil is substantially rectangular, and the central portions of the left and right sides of the geomagnetism correction coil are curved toward the inside of the rectangle so as to approach the deflection yoke. And a geomagnetism correction device. 5. A terrestrial magnetism correction circuit and a terrestrial magnetism correction coil are provided, said terrestrial magnetism correction coil having a substantially rectangular shape, and the central portions of the left and right sides thereof are curved toward the inside of the rectangle so as to approach the deflection yoke. A cathode ray tube comprising a structured geomagnetism correction device. 6. The geomagnetic correction coil has a substantially rectangular shape,
A cathode ray tube comprising a geomagnetism correction device having a structure in which central portions of the left and right sides are curved toward the inside of a rectangle so as to approach a deflection yoke.