X-ray tube electron beam switching and biasing method and apparatus
US4685118A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 3, 1985 |
| Grant date | Aug 4, 1987 |
| Priority date | — |
| Expiry date | Jul 3, 2005 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2235/068
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
An X-ray tube having a capability to produce multiple anode spots. The X-ray tube can produce three or more different size anode focal spots without modification of the connectors, cabling, or high voltage supply for routing high voltage signals to the X-ray tube. An isolating fiber optic control input connects an external light emitting diode to a controller inside the tube housing. The controller responds to light signals from the light emitting diode to control the size of focus spots on the tube anode. In a preferred embodiment each of three filaments are individually energized to produce three different size focal spots and a cathode cup to which the filaments are mounted is also biased to add a four spot capability. In an alternate embodiment a split or segmented cathode cup has its segments biased to different electrical potentials by tapping power from a conventional high voltage filament supply used in energizing a cathode filament. Confirmation circuitry monitors operation of the controller and deactivates the X-ray tube in the event of a controller malfunction.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.