Apparatus and method for shaping high voltage potentials on an insulator
AssigneeVarian Medical Systems, Inc.
InventorCharles Lynn Chidester
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Abstract
An apparatus and method for reducing the incidence of electric field stress on portions of insulating structures within high voltage devices is disclosed. Each of the embodiments disclosed herein modifies the conductive properties of the insulating structure surface in a non-uniform manner such that the distribution of voltage potential along the surface thereof is more fully equalized during operation of the high voltage device. This, in turn, reduces the per unit stress on the insulating structure caused by the electric field of the high voltage device. Though embodiments of the present invention are preferably directed to utilization in x-ray tube devices, a variety of high voltage devices may benefit from application of the disclosed matter.
Claims42
An insulating structure for use in a high voltage device, wherein at least a portion of the structure is configured such that the surface thereof possesses an electrical conductivity that varies as a function of position on the surface of the insulating structure.
A method for manufacturing an insulating structure for use in a high voltage device such that the voltage potential distribution along the surface of the insulating structure is modified during operation of the high voltage device, the method comprising the steps of:
- applying to at least a portion of the surface of the insulating structure a layer of coating material having an electrical conductivity greater than the conductivity of the material of which the insulating structure is composed;
- and
- varying a characteristic of the applied layer of coating material such that the applied layer is non-uniform.
A method for manufacturing an insulating structure for use in an x-ray tube such that the voltage potential along a surface of the anode insulating structure is modified during operation of the x-ray tube, wherein the insulating structure comprises leaded glass, the method comprising the steps of:
- (a) masking a portion of the surface of the insulating structure;
- (b) heating the insulating structure in a hydrogen-rich atmosphere such that the conductivity of the unmasked portions of at least a portion of the surface of the structure is increased;
- (c) unmasking the portion of the surface of the insulating structure;
- (d) cooling the insulating structure;
- (e) masking a lesser portion of the surface of the insulating structure than was previously masked;
- and
- (f) repeating steps (b) through (e) as desired.
A method for manufacturing an insulating structure for use in a high voltage producing device such that the voltage potential along the surface of the insulating structure is modified during operation of the high voltage device, wherein the insulating structure comprises a cylindrical surface, the method comprising the steps of:
- applying a layer of coating material to the cylindrical surface of the insulating structure, the coating material having an electrical conductivity greater than the surface of the material comprising the insulating structure;
- and
- defining a non-uniform groove in the layer of coating material such that a portion of the cylindrical surface of the insulating structure is exposed by the groove.
A method for manufacturing an insulating structure for use in a high voltage device such that the voltage potential along the surface of the insulating structure is modified during operation of the high voltage device, the insulating structure comprising two or more segments comprising distinct materials, each material having surfaces with different electrical conductivities, the method comprising the steps of:
- joining the two or more segments together to form the insulating structure;
- heating the insulating structure;
- and
- shaping the two or more segments to a desired shape such that the electrical conductivity varies along the surface of the insulating structure.
An x-ray tube comprising:
- a vacuum enclosure having disposed therein a cathode for producing electrons, and an anode positioned to receive electrons emitted by the cathode;
- a cathode insulating structure affixed to the cathode for electrically isolating the cathode from other portions of the x-ray tube;
- an anode insulating structure affixed to the anode for electrically isolating the cathode from other portions of the x-ray tube;
- and
- means for modifying the voltage potential along the surface of at least one of the insulating structures of the x-ray tube during operation thereof.
An x-ray tube comprising:
- a vacuum enclosure having disposed therein a cathode for producing electrons and an anode positioned to receive the electrons emitted by the cathode;
- a cathode insulator for electrically isolating a high voltage potential produced by the cathode from other portions of the x-ray tube;
- an anode insulator for electrically isolating a high voltage potential produced by the anode from other portions of the x-ray tube;
- and
- a layer of coating material applied in a non-uniform fashion to the surface of at least one of the cathode and anode insulators for modifying the voltage potential along the surface thereof.
Dependencies are inferred from the claim text.