Patent ID: 6760407
Filing Date: 2004-07-06
Classification: H01J

Abstract:
An X-ray source comprising:a cold cathode, the cold cathode having a curved emission surface capable of emitting electrons; and an anode, the anode being spaced apart from the cathode, the anode being capable of emitting X-rays in response to being bombarded with electrons emitted from the curved emission surface; wherein the cold cathode comprises a plurality of emitters disposed on a substrate and a gate conductor disposed adjacent the plurality of emitters, and wherein the plurality of emitters are operative to emit electrons when a bias voltage is applied to the gate conductor; wherein the electrons bombard the anode at a focal spot of the anode, wherein the plurality of emitters comprises a first set of emitters, the first set of emitters being operative to emit a first electron beam having a first focal spot with a first shape, and a second set of emitters, the second set of emitters being operative to emit a second electron beam having a second focal spot with a second shape, the second shape being different than the first shape, and wherein the first set of emitters and the second set of emitters are located on the same curved emission surface and are separately energizable.