US3676670A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electron gun biasing system
Assignee: Etec Systems Inc
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Filing: 1970-10-09
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Granted: 1972-07-11
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Expires: 1990-10-09
Abstract
Abstract An electron gun biasing system, particularly adapted for use in an electron microscope, in which a plurality of resistors are provided in series with the cathode of the electron gun. In parallel with each of the resistors is a photoconductor, and means are provided for selectively illuminating the various photoconductors so as to short out various resistors, and thus vary the bias. Typically, the resistors and photoconductors may be located inside a shielded box, and a plurality of light pipes may be directed through openings in the shielded box, so that the ends of the light pipes will be adjacent the photoconductors. A plurality of lamps may then be disposed at the ends of the light pipes outside the box, the lamps being selectively illuminated by a simple lamp illumination circuit.
Inventors
- 👤 James Dao
- 👤 Nelson C Yew
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 11:05
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/02; H01J37/24; H01J37/243
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
102 words
In an electron gun having a cathode, a grid disposed adjacent said cathode, and a source of high voltage D.C., said grid being connected to said source of high voltage, the improvement comprising: a plurality of resistors connected end to end to form a sEries circuit solely of resistors, one end of said series resistors being connected to said cathode and the other end of said series resistors being connected to said source of high voltage, a plurality of photoconductors, each of said photoconductors being connected in parallel with one of said resistors, and means for selectively illuminating said photoconductors on demand.
Claim 2
Dependent Claim
102 words
In an electron gun having a cathode, a grid disposed adjacent said cathode, and a source of high voltage D.C., said grid being connected to said source of high voltage, the improvement comprising: a plurality of resistors connected end to end to form a sEries circuit solely of resistors, one end of said series resistors being connected to said cathode and the other end of said series resistors being connected to said source of high voltage, a plurality of photoconductors, each of said photoconductors being connected in parallel with one of said resistors, and means for selectively illuminating said photoconductors on demand.
Claim 3
Dependent Claim
21 words
Apparatus according to claim 1 further comprising a shielded box, said resistors and said photoconductors being disposed within said shielded box.
Claim 4
Dependent Claim
40 words
Apparatus according to claim 2 wherein said means for selectively illuminating said photoconductors comprises a plurality of lamps, means for selectively illuminating said lamps on demand, and means for optically coupling each of said lamps with one of said photoconductors.
Claim 5
Dependent Claim
78 words
Apparatus according to claim 3 wherein said lamps are disposed outside of said shielded box, said shielded box having a plurality of apertures therein and said optical coupling means comprising a plurality of light pipes, said light pipes passing through said apertures in said shielded box, one end of each of said light pipes being disposed adjacent one of said photoconductors and the other end of each of said light pipes being disposed adjacent one of said lamps.
Claim 6
Dependent Claim
100 words
An electron gun D.C. biasing system comprising a cathode, a grid disposed adjacent said cathode, a source of high voltage D.C., said grid being connected to said source of high voltage, a plurality of resistors connected end to end to form a series circuit solely of resistors, one end of said series resistors being connected to said cathode and the other end of said series resistors being connected to said source of high voltage, a plurality of photoconductors, each of said photoconductors being connected in parallel with one of said resistors, and means for selectively illuminating said photoconductors on demand.
Claim 7
Dependent Claim
100 words
An electron gun D.C. biasing system comprising a cathode, a grid disposed adjacent said cathode, a source of high voltage D.C., said grid being connected to said source of high voltage, a plurality of resistors connected end to end to form a series circuit solely of resistors, one end of said series resistors being connected to said cathode and the other end of said series resistors being connected to said source of high voltage, a plurality of photoconductors, each of said photoconductors being connected in parallel with one of said resistors, and means for selectively illuminating said photoconductors on demand.
Claim 8
Dependent Claim
21 words
Apparatus according to claim 5 further comprising a shielded box, said resistors and said photoconductors being disposed within said shielded box.
Claim 9
Dependent Claim
40 words
Apparatus according to claim 6 wherein said means for selectively illuminating said photoconductors comprises a plurality of lamps, means for selectively illuminating said lamps on demand, and means for optically coupling each of said lamps with one of said photoconductors.
Claim 10
Dependent Claim
78 words
Apparatus according to claim 7 wherein said lamps are disposed outside of said shielded box, said shielded box having a plurality of apertures therein and said optical coupling means comprising a plurality of light pipes, said light pipes passing through said apertures in said shielded box, one end of each of said light pipes being disposed adjacent one of said photoconductors and the other end of each of said light pipes being disposed adjacent one of said lamps.
Claim 11
Dependent Claim
131 words
In an electron microscope having a housing containing a specimen, a cathode disposed within said housing, a grid disposed adjacent said cathode, a source of high voltage D.C., said grid being connected to said source of high voltage, means for focusing the electrons emitted by said cathode on said specimen and means for evacuating the interior of said housing, the improvement comprising: a plurality of resistors connected end to end to form a series circuit solely of resistors, one end of said series resistors being connected to said cathode and the other end of said series resistors being connected to said source of high voltage, a plurality of photoconductors, each of said photoconductors being connected in parallel with one of said resistors, and means for selectively illuminating said photoconductors on demand.
Claim 12
Dependent Claim
131 words
In an electron microscope having a housing containing a specimen, a cathode disposed within said housing, a grid disposed adjacent said cathode, a source of high voltage D.C., said grid being connected to said source of high voltage, means for focusing the electrons emitted by said cathode on said specimen and means for evacuating the interior of said housing, the improvement comprising: a plurality of resistors connected end to end to form a series circuit solely of resistors, one end of said series resistors being connected to said cathode and the other end of said series resistors being connected to said source of high voltage, a plurality of photoconductors, each of said photoconductors being connected in parallel with one of said resistors, and means for selectively illuminating said photoconductors on demand.
Claim 13
Dependent Claim
21 words
Apparatus according to claim 9 further comprising a shielded box, said resistors and said photoconductors being disposed within said shielded box.
Claim 14
Dependent Claim
40 words
Apparatus according to claim 10 wherein said means for selectively illuminating said photoconductors comprises a plurality of lamps, means for selectively illuminating said lamps on demand, and means for opticaLly coupling each of said lamps with one of said photoconductors.
Claim 15
Dependent Claim
77 words
Apparatus according to claim 11 wherein said lamps are disposed outside of said shielded box, said shielded box having a plurality of apertures therein and said optical coupling means comprising a plurality of light pipes, said light pipes passing through said apertures in said shielded box, one end of each of said light pipes being disposed adjacent one of said photoconductors and the other of each of said light pipes being disposed adjacent one of said lamps.
Claim 16
Dependent Claim
144 words
In a scanning electron microscope having a housing containing a specimen, a cathode disposed within said housing, a grid disposed adjacent said cathode, a source of high voltage D.C., said grid being connected to said source of high voltage, means for focusing the electrons emitted by said cathode on said specimen, means for scanning the electrons emitted by said cathode on said specimen, and means for evacuating the interior of said housing, the improvement comprising: a plurality of resistors connected end to end to form a series circuit solely of resistors, one end of said series resistors being connected to said cathode and the other end of said series resistors being connected to said source of high voltage, a plurality of photoconductors, each of said photoconductors being connected in parallel with one of said resistors, and means for selectively illuminating said photoconductors on demand.
Claim 17
Dependent Claim
144 words
In a scanning electron microscope having a housing containing a specimen, a cathode disposed within said housing, a grid disposed adjacent said cathode, a source of high voltage D.C., said grid being connected to said source of high voltage, means for focusing the electrons emitted by said cathode on said specimen, means for scanning the electrons emitted by said cathode on said specimen, and means for evacuating the interior of said housing, the improvement comprising: a plurality of resistors connected end to end to form a series circuit solely of resistors, one end of said series resistors being connected to said cathode and the other end of said series resistors being connected to said source of high voltage, a plurality of photoconductors, each of said photoconductors being connected in parallel with one of said resistors, and means for selectively illuminating said photoconductors on demand.
Claim 18
Dependent Claim
21 words
Apparatus according to claim 13 further comprising a shielded box, said resistors and said photoconductors being disposed within said shielded box.
Claim 19
Dependent Claim
40 words
Apparatus according to claim 14 wherein said means for selectively illuminating said photoconductors comprises a plurality of lamps, means for selectively illuminating said lamps on demand, and means for optically coupling each of said lamps with one of said photoconductors.
Claim 20
Dependent Claim
78 words
Apparatus according to claim 15 wherein said lamps are disposed outside of said shielded box, said shielded box having a plurality of apertures therein and said optical coupling means comprising a plurality of light pipes, said light pipes passing through said apertures in said shielded box, one end of each of said light pipes being disposed adjacent one of said photoconductors and the other end of each of said light pipes being disposed adjacent one of said lamps.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-07-11 | 1976-01-10 | 1976-07-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-07-11 | 1980-01-10 | 1980-07-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-07-11 | 1984-01-10 | 1984-07-11 | $7700.00 | Window Closed / Lapsed |