JPH07240934A - Automatic geomagnetism corrector - Google Patents

Abstract

PURPOSE:To form the automatic geomagnetism corrector capable of varying a current to be supplied from an geomagnetism correcting current generating circuit to a coil for geomagnetism correction corresponding to geomagnetism so as to eliminate picture inclination or color nonuniformity even with any geomagnetism. CONSTITUTION:This device is provided with a geomagnetism detector 3 for outputting a voltage corresponding to the geomagnetism, the output voltage of the geomagnetism detector 3 is inputted to a correction amount control circuit 4 and with the output of the correction amount control circuit 4 as a reference voltage, a current direction and a required current value are set from a geomagnetism correcting current generating circuit 5 and supplied to a coil 2 for geomagnetism correction. Thus, the current to be supplied to the coil 2 for geomagnetism correction is automatically varied corresponding to the geomagnetism. Therefore, the geomagnetism can be automatically canceled at any destination or direction.

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 receiver and the like, and more particularly to a geomagnetism correction device capable of always correcting screen tilt and color unevenness according to geomagnetism.

[0002]

2. Description of the Related Art In a display device, a television receiver or the like which is compatible with various geomagnetisms, it is necessary to cancel the geomagnetism in order to correct an adverse effect on the screen (for example, screen tilt, color unevenness).

Conventionally, in order to solve the above-mentioned problems, a geomagnetic correction coil is used, and the geomagnetism is detected after a lapse of time from the power-on of a set such as a display device and a television receiver to the end of the operation of the degaussing circuit. From the results, the direction of the geomagnetic correction current and the required value were set to correct the geomagnetism.

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

[0005]

In the above prior art, since the geomagnetism is detected and the direction of the geomagnetism correction current and the necessary value are set after the operation of the degaussing circuit is completed after the power supply of the set is turned on, the power is turned on after the power is turned on. However, when the set was rotated after a while, problems such as screen tilt and color unevenness were problems.

An object of the present invention is to always perform automatic geomagnetic correction regardless of the state (destination, direction) of the set in order to prevent problems such as screen tilt and color unevenness.

[0007]

In order to achieve the above object, according to the present invention, a geomagnetism detector for detecting the geomagnetism is provided, and the reference voltage used in the geomagnetism correction current generating circuit is set to the output voltage of the correction amount control circuit. By using, it is possible to automatically and constantly correct according to the geomagnetism.

[0008]

When the geomagnetism is input to the geomagnetism detection device, a voltage corresponding to the geomagnetism is obtained at the output. This voltage is input as the reference voltage of the correction amount control circuit.

When the geomagnetism changes, the output voltage from the geomagnetism detecting device changes correspondingly, and the reference voltage of the correction amount control circuit also changes.

Since the output of the control circuit in the geomagnetic correction current generating circuit is fed back to the correction amount control circuit, the output of the geomagnetic correction current generating circuit also changes when the reference voltage changes. Therefore, the output of the geomagnetic correction current generation circuit changes according to the change of the geomagnetism.

[0011]

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 present invention.

In FIG. 1, 1 is a cathode ray tube, 2 is a geomagnetism correction coil, 3 is a geomagnetism detection device, 4 is a correction amount control circuit, and 5 is a geomagnetism correction current generation circuit.

In FIG. 1, when geomagnetism is generated in the set, it is detected by the geomagnetism detection device 3, and its output voltage is supplied as a reference voltage of the correction amount control circuit 4. A current required for geomagnetic correction is supplied to the geomagnetic correction coil 2 by the geomagnetic correction current generating circuit 5 to which the reference voltage is applied.

[0015]

According to the present invention, since a correction current corresponding to the geomagnetism can be supplied to the geomagnetic correction coil, the geomagnetism can always be canceled even if the geomagnetism changes, and screen tilt and color unevenness can be corrected. You can

[Brief description of drawings]

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

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Braun tube, 2 ... Geomagnetic correction coil, 3 ... Geomagnetic detection device, 4 ... Correction amount control circuit, 5 ... Geomagnetic correction current generation circuit.

Claims (1)

[Claims] 1. A terrestrial magnetism correction coil, a terrestrial magnetism detection device, a correction amount control circuit, and a terrestrial magnetism correction current generation circuit. A detector is provided to correct screen tilt and color unevenness due to terrestrial magnetism, and the detection is performed. An automatic geomagnetism correction device characterized in that the output voltage of the device is used as a reference voltage and the correction coil is used to set a current value and a direction required for the correction to constantly correct the screen.