X-ray tube with capacitively coupled filament drive

A rotating anode x-ray tube comprising:

• an evacuated envelope;
• an anode formed at least along an annular surface adjacent one end of the envelope;
• a cathode assembly rotatably mounted within the envelope, the cathode assembly including a cathode means which undergoes thermionic emission under electrical stimulation;
• a means for rotating the envelope and anode;
• a means for holding the cathode assembly stationary as the envelope and anode rotate;
• at least first and second capacitor members mounted to the cathode assembly, the first and second capacitor members being mounted inside of the envelope and closely adjacent thereto, the cathode means being connected with the first and second capacitor members to receive electrical stimulation therefrom;
• third and fourth capacitor members mounted exterior to the envelope and closely adjacent thereto, the third capacitor member being capacitively coupled to the first capacitor member and the fourth capacitor member being capacitively coupled to the second capacitor member, such that the capacitor members transfer stimulating AC electrical power from an external AC electrical source to the cathode means.

An x-ray tube comprising:

• an evacuated envelope;
• an anode formed at least along an annular surface within the envelope;
• a cathode assembly rotatably mounted within the envelope;
• a capacitive coupling means for providing an AC electrical communication path from an exterior of the envelope to an interior of the envelope, the capacitive coupling means being connected with the cathode assembly.