Magnetic cancelling apparatus for color cathode-ray tube
AssigneeMitsubishi Denki Kaisha Kaisha
InventorHidenori Takita
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Abstract
A magnetic cancelling apparatus for a color cathode-ray tube which is to cancel external magnetic fields acting on the color cathode-ray tube, can prevent deterioration of the screen color purity. The apparatus includes a magnetic sensor for detecting a magnetic field in a predetermined direction acting on the cathode-ray tube. The output of the magnetic sensor is amplified and then fed to a cancelling coil, thereby permitting the screen purity to be kept in best condition even under change in direction of the external magnetic field such as the geomagnetism.
Claims3
A magnetic cancelling apparatus for a color cathode-ray tube, comprising:
- a magnetic sensor for detecting an external magnetic field acting on said color cathode-ray tube in a direction parallel to the axis of said tube;
- an amplifier for amplifying an output signal provided from said magnetic sensor;
- and
- a cancelling coil wound annularly around the periphery of said tube and energized by an output signal from said amplifier for generating a magnetic field cancelling said external magnetic field.
Dependencies are inferred from the claim text.