Cathode-ray tube and semiconductor device for use in such a cathode-ray tube
AssigneeU.S. Philips Corporation
InventorsArthur M. E. Hoeberechts, Gerardus G. P. van Gorkom
Life of this patent
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Abstract
A semiconductor cathode is provided with deflection electrodes, with which a dipole field can be generated. As a result of this, electrons released at the surface of the semiconductor cathode leave the surface at a certain angle. For use inter alia in camera tubes, display tubes, such an inclined beam can be aligned without any problems. Positive ions which are released inter alia from residual gases and are accelerated in the direction of the cathode impinge on the cathode at an acute angle. As a result of this, the active part of the cathode is substantially not attacked by said positive ions, so that degradation is prevented.
Claims13
A device for recording or displaying pictures, comprising an elongated cathode-ray tube with an elongated axis and having, in an evacuated envelope, a target and a semiconductor cathode having a semiconductor body with a major surface on which a first electrically insulating material layer having at least one aperture is provided, which semiconductor body comprises at least a p-n junction in which the application of voltage in the reverse direction across the p-n junction causes electrons to be generated in the semiconductor body by avalanche multiplication, said electrons emanating from the semiconductor body at the area of the aperture in the first electrically insulating material, and in which at least an accelerating electrode is provided on the first electrically insulating material at least at the area of the edge of the aperture in said layer, wherein the improvement comprises additional electrically-insulating material covering at least part of the semiconductor body other than said aperture in the first insulating material, said additional electrically insulating material having at least two deflection electrodes on it for generating a static dipole field.
A device for recording or displaying pictures comprising an elongated cathode-ray tube with an elongated axis and having, in an evacuated envelope, a target and a semiconductor cathode comprising a semiconductor body having a major surface, a p-type surface zone at said major surface and comprising at least two connections of which at least one comprises an injecting connection at a distance from the major surface which is smaller than the diffusion recombination length of electrons in the p-type surface zone, characterized in that the major surface is covered at least partly with an electrically insulating layer which leaves at least a part of the p-type surface zone uncovered, at least two deflection electrodes being provided on said electrically insulating layer for generating a static dipole field.
Dependencies are inferred from the claim text.