JPH08307889A - Automatic earth magnetism correction device - Google Patents

Abstract

PURPOSE: To correct the earth magnetism automatically with higher accuracy corresponding to a change in earth magnetism at any time. CONSTITUTION: A magnetism detector 4 detects total sum of magnetism in the device and gives a voltage depending on the total sum to a magnetism comparator 5. The magnetism comparator 5 catches a change in the total sum of the magnetism as a voltage change and gives a voltage required to correct the earth magnetism to correction current generators 6, 7, 8. Then a current outputted by the correction current generators 6, 7, 8 is supplied to correction coils 1, 2, 3 to make the total sum of the magnetism in the device constant at all times thereby correcting the effect of the earth magnetism.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device, a television device or the like for automatically correcting a change in the state of a screen caused by the influence of the earth's magnetism.

[0002]

2. Description of the Related Art A conventional geomagnetic correction circuit uses a geomagnetic detection result after a lapse of time from when the power of a television receiver set is turned on to when the operation of the degaussing circuit is almost completed.
The current direction and required current value of the geomagnetic correction current are set and stored, and the geomagnetic correction current increases from 0 to the set current direction by a predetermined step every specified time, and rises to the set required current value. A current data signal is created so as to be supplied to the geomagnetic correction current generation circuit.

However, in this case, since the geomagnetic correction circuit operates only when the power is turned on, the geomagnetic correction is not performed even if the orientation of the screen is changed after the power is turned on.

Such a known example is disclosed in JP-A-5-1459.
No. 36 publication.

[0005]

In the conventional geomagnetism correction circuit described above, the geomagnetism correction circuit is made to perform the geomagnetism correction operation only when the power is turned on. The geomagnetism correction operation is not performed, and the screen tilt and the purity / convergence shift continue to occur.

Therefore, the present invention eliminates the above problems,
It is an object of the present invention to provide a geomagnetism correction device capable of automatically performing geomagnetism correction at any time.

[0007]

In order to achieve the above object, the geomagnetism correction device according to the present invention has an X, Y, Z in the device.
One set of axial correction coils and a magnetic detection device are provided. With this magnetic detection device, changes in the total sum of the magnetism generated by the geomagnetism and the correction coil itself are detected, and the changes in the total magnetism are corrected by the detected values. A magnetic correction current required for this purpose is passed through the correction coil so that the total magnetism in the device is always constant, so that the influence of geomagnetism can be corrected at any time.

[0008]

With this configuration, the geomagnetism can be constantly corrected not only when the power is turned on, but also when the screen orientation is changed after the power is turned on. Therefore, the tilt of the screen and the purity / convergence deviation can be corrected with higher accuracy at any time. You can do it.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG.

FIG. 1 is a block diagram showing an embodiment of the geomagnetism correction device of the present invention.

In FIG. 1, magnetism in the X-, Y-, and Z-axis directions in the apparatus is detected by the magnetic detection apparatus 4, and a voltage corresponding to the detected value is supplied to the magnetic comparison apparatus 5. Then, this magnetic comparison device compares the voltage value at the time of factory adjustment completion with the input voltage, and the voltage required to correct the change in magnetism is the correction current generation device 6, 7 for controlling each axial direction. 8
Is supplied to. Then, the current output by the correction current generator 6 is passed through the X-axis direction correction coil 1, and the current output by the correction current generator 7 is passed by the Y-axis direction correction coil 2.
The current output by the correction current generator 8 to Z
The influence of the geomagnetism is corrected at any time by flowing it in the axial correction coil 3 so that the total sum of the magnetism in the device always coincides with the completion of the factory adjustment.

[0012]

According to the present invention, a correction current corresponding to a change in the earth's magnetism can be supplied to the correction coil at any time, and by keeping the total sum of magnetism in the apparatus constant, the tilt of the screen and the purity Convergence deviation can be corrected automatically with higher accuracy.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of a geomagnetism correction device of the present invention.

[Explanation of symbols]

1 ... X-axis direction correction coil, 2 ... Y-axis direction correction coil, 3
... Z-axis direction correction coil, 4 ... Magnetic detection device, 5 ... Magnetic comparison device, 6 ... Correction current generator (X-axis direction), 7 ... Correction current generator (Y-axis direction), 8 ... Correction current generator ( Z
Axial direction), 9 ... CRT.

Claims (1)

[Claims] 1. A display device using a cathode ray tube, wherein a device for detecting a sum of a coil for generating a reference magnetic field by itself and a magnetism outside the device is provided in the display device, and a change in total magnetism is detected, A geomagnetism correction device characterized in that a magnetic field that cancels out the change is generated in the coil to constantly automatically correct a change in screen state.