US Patent 7496180 Focal spot temperature reduction using three-point deflection

An x-ray tube includes an anode comprising a focal track and a cathode assembly configured to emit an electron beam toward a focal spot on the focal track. The x-ray tube also includes a controller configured to wobble the electron beam among a plurality of focal points in a direction tangent to the focal track. The plurality of focal points includes at least one focal point that is bounded by a pair of boundary focal points. The controller is further configured to delay a wobble of the electron beam away from the at least one focal point for a pre-determined amount of time.