US4346325A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electron gun
Assignee: Toshiba Corp
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Filing: 1980-03-27
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Granted: 1982-08-24
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Expires: 2000-03-27
Abstract
Abstract An electron gun for a shaped beam type electron beam delineating system is provided with a cathode which is prepared from a single crystal of lanthanum hexaboride (LaB 6 ) the convex end portion of which has a tip radius ranging between 260 and 1,000 microns. The electron gun of the invention has a long effective life for producing a stable electron beam which can irradiate a limiting aperture with a uniform current density and insures the sufficiently high brightness of the electron beam image projected on a target.
Inventors
- 👤 Mamoru Nakasuji
- 👤 Hirotsugu Wada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 19:06
CPC Classifications
H; H01; H01J; H01J1/00; H01J1/02; H01J1/13; H01J1/15; H01J1/16; H01J37/00; H01J37/02; H01J37/04; H01J37/06
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
35 words
An electron gun for a shaped-beam-type electron beam delineating system, comprising: a cathode including a single crystal of lanthanum hexaboride having a convex end portion with a tip radius ranging between 260 and 1,000 microns.
Claim 2
Dependent Claim
35 words
An electron gun for a shaped-beam-type electron beam delineating system, comprising: a cathode including a single crystal of lanthanum hexaboride having a convex end portion with a tip radius ranging between 260 and 1,000 microns.
Claim 3
Dependent Claim
25 words
The electron gun according to claim 1, wherein the convex end portion of said cathode has a tip radius ranging between 300 and 600 microns.
Claim 4
Dependent Claim
23 words
The electron gun according to claim 1 or 2, wherein the convex end portion of said cathode has a crystal orientation of <110>.
References Cited (Backward Citations)
FR603005A
Cited
US4055780A
Cited
JPS5230151A
Cited
US4054946A
Cited
US4137476A
Cited
US4200555A
Cited
US4258283A
Cited
US4260525A
Cited
JPS5588233A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-08-23 | 1986-02-22 | 1986-08-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-08-23 | 1990-02-22 | 1990-08-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-08-23 | 1994-02-22 | 1994-08-24 | $7700.00 | Window Closed / Lapsed |