Cathode blade for a field emission x-ray tube
Abstract
Abstract A cathode blade comprising a thin electron emitting layer formed from tungsten that projects from a copper support layer. The tungsten layer is extremely thin so that electrons will be readily emitted from the edge of the blade without requiring that the portion of the blade proximate the electron emitting edge be tapered. The copper support layer is spaced from the electron emitting edge of the tungsten layer, and therefore, does not reduce the sharpness of that edge. The blade is formed by vapor depositing a thin tungsten layer on a copper layer that is somewhat larger than the desired blade. The copper and tungsten layers are covered with coatings that are unaffected by electroetching processes for removing unwanted portions of those layers. The portions of the copper and tungsten layers having outlines corresponding to the desired outlines of the copper and tungsten layers respectively of the desired blade are masked. The protective coating is removed from the remaining unmasked surfaces. The exposed portion of each layer is then removed by electro-etching.
Inventors
- 👤 W Rogers
- 👤 R Ayres
Bibliographic Details
Claims Analysis
Total Claims: 3References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-05-21 | 1976-11-20 | 1977-05-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-05-21 | 1980-11-20 | 1981-05-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-05-21 | 1984-11-20 | 1985-05-22 | $7700.00 | Window Closed / Lapsed |