US3887839A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pulsed field emission type electron gun
Assignee: Jeol Ltd
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Filing: 1973-07-10
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Granted: 1975-06-03
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Expires: 1993-07-10
Abstract
Abstract A pulsed field emission type electron gun in which the pulse voltage peak between the heated emitter and its associated electrode is maintained constant, and the pulse duty factor or emitter heating temperature of bias voltage is controlled to keep the field emitted electron beam constant, during the pulse rest time, thereby prolonging the life of the emitter regardless of any discrepancy between the radius of curvature of one emitter and another.
Inventors
- 👤 Susumu Ota
- 👤 Ryuzo Aihara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 03:10
CPC Classifications
H; H01; H01J; H01J3/00; H01J3/02; H01J3/021
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
114 words
A field emission type electron gun comprising: a. an emitter having a tip, b. a control electrode, c. a power supply for supplying a pulse voltage having a constant peak value between said emitter and Control electrode such that during the pulse an intense electric field in the vicinity of the emitter tip causes field emission therefrom and for supplying a bias voltage between pulses, d. means for heating said emitter, e. means for detecting the emitter current and f. means responsive to the emitter current for adjusting one of the heating means and/or power supply to maintain the current substantially constant whereby the radius of curvature of the emitter tip remains substantially constant.
Claim 2
Dependent Claim
114 words
A field emission type electron gun comprising: a. an emitter having a tip, b. a control electrode, c. a power supply for supplying a pulse voltage having a constant peak value between said emitter and Control electrode such that during the pulse an intense electric field in the vicinity of the emitter tip causes field emission therefrom and for supplying a bias voltage between pulses, d. means for heating said emitter, e. means for detecting the emitter current and f. means responsive to the emitter current for adjusting one of the heating means and/or power supply to maintain the current substantially constant whereby the radius of curvature of the emitter tip remains substantially constant.
Claim 3
Dependent Claim
114 words
A field emission type electron gun comprising: a. an emitter having a tip, b. a control electrode, c. a power supply for supplying a pulse voltage having a constant peak value between said emitter and Control electrode such that during the pulse an intense electric field in the vicinity of the emitter tip causes field emission therefrom and for supplying a bias voltage between pulses, d. means for heating said emitter, e. means for detecting the emitter current and f. means responsive to the emitter current for adjusting one of the heating means and/or power supply to maintain the current substantially constant whereby the radius of curvature of the emitter tip remains substantially constant.
Claim 4
Dependent Claim
114 words
A field emission type electron gun comprising: a. an emitter having a tip, b. a control electrode, c. a power supply for supplying a pulse voltage having a constant peak value between said emitter and Control electrode such that during the pulse an intense electric field in the vicinity of the emitter tip causes field emission therefrom and for supplying a bias voltage between pulses, d. means for heating said emitter, e. means for detecting the emitter current and f. means responsive to the emitter current for adjusting one of the heating means and/or power supply to maintain the current substantially constant whereby the radius of curvature of the emitter tip remains substantially constant.
Claim 5
Dependent Claim
114 words
A field emission type electron gun comprising: a. an emitter having a tip, b. a control electrode, c. a power supply for supplying a pulse voltage having a constant peak value between said emitter and control electrode such that during the pulse an intense electric field in the vicinity of the emitter tip causes field emission therefrom and for supplying a bias voltage between pulses, d. means for heating said emitter, e. means for detecting the emitter current and f. means responsive to the emitter current for adjusting the power supply to vary the duty factor to maintain the current substantially constant whereby the radius of curvature of the emitter tip remains substantially constant.
Claim 6
Dependent Claim
114 words
A field emission type electron gun comprising: a. an emitter having a tip, b. a control electrode, c. a power supply for supplying a pulse voltage having a constant peak value between said emitter and control electrode such that during the pulse an intense electric field in the vicinity of the emitter tip causes field emission therefrom and for supplying a bias voltage between pulses, d. means for heating said emitter, e. means for detecting the emitter current and f. means responsive to the emitter current for adjusting the power supply to vary the duty factor to maintain the current substantially constant whereby the radius of curvature of the emitter tip remains substantially constant.
Claim 7
Dependent Claim
116 words
A field emission type electron gun comprising: a. an emitter having a tip, b. a control electrode, c. a power supply for supplying a pulse voltage having a constant peak value between said emitter and control electrode such that during the pulse an intense electric field in the vicinity of the emitter tip causes field emission therefrom and for supplying a bias voltage between pulses, d. means for heating said emitter, e. means for detecting the emitter current and f. means responsive to the emitter current for adjusting the power supply to vary the bias voltage between pulses to maintain the current substantially constant whereby the radius of curvature of the emitter tip remains substantially constant.
Claim 8
Dependent Claim
116 words
A field emission type electron gun comprising: a. an emitter having a tip, b. a control electrode, c. a power supply for supplying a pulse voltage having a constant peak value between said emitter and control electrode such that during the pulse an intense electric field in the vicinity of the emitter tip causes field emission therefrom and for supplying a bias voltage between pulses, d. means for heating said emitter, e. means for detecting the emitter current and f. means responsive to the emitter current for adjusting the power supply to vary the bias voltage between pulses to maintain the current substantially constant whereby the radius of curvature of the emitter tip remains substantially constant.
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) | 1978-06-02 | 1978-12-02 | 1979-06-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-02 | 1982-12-02 | 1983-06-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-02 | 1986-12-02 | 1987-06-03 | $7700.00 | Window Closed / Lapsed |