Patent US3192921A successfully refreshed from Google Patents.
US3697833A
Expired / Lapsed
US
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Light activated thyristor
Assignee: Mitsubishi Electric Corp
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Filing: 1971-02-18
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Granted: 1972-10-10
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Expires: 1991-02-18
Abstract
Abstract The disclosed thyristor includes an annular N emitter layer disposed on a P base layer to encircle the central portion of the latter. Another N emitter layer is disposed on the exposed surface of the central base portion to form an auxiliary thyristor around which a main thyristor is formed. The auxiliary thyristor responds to light falling upon its emitter layer to be fired. A current flowing through the fired thyristor flows into the annular emitter layer through a gate electrode bridging the auxiliary emitter layer and P base layer to fire the main thyristor.
Inventors
- 👤 Josuke Nakata
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 11:24
CPC Classifications
H; H10; H10F; H10F30/00; H10F30/20; H10F30/21; H10F30/26; H10F30/263
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
184 words
A light activated thyristor comprising, in combination a wafer of semiconductive material including, a first layer of one type conductivity, a second layer of opposite type conductivity disposed on said first layer to form a first P-N junction therebetween, a third layer of one type conductivity disposed on said second layer to form a second P-N junction therebetween, a fourth layer of opposite type conductivity disposed on said third layer to form a third P-N junction therebetween and a fifth layer of opposite type conductivity disposed on said third layer to form a fourth P-N junction therebetween, said fifth layer having a portion defining an exposed surface providing a light recEiving surface, said portion being of lesser thickness than said fourth layer; said third layer having a portion encircling said fifth layer; a gate electrode disposed in ohmic contact with adjacent portions of said fifth and third layers to electrically bridge the latter, a first main electrode disposed in ohmic contact with the surface of said first layer, and a second main electrode disposed in ohmic contact with the surface of said fourth layer.
Claim 2
Dependent Claim
184 words
A light activated thyristor comprising, in combination a wafer of semiconductive material including, a first layer of one type conductivity, a second layer of opposite type conductivity disposed on said first layer to form a first P-N junction therebetween, a third layer of one type conductivity disposed on said second layer to form a second P-N junction therebetween, a fourth layer of opposite type conductivity disposed on said third layer to form a third P-N junction therebetween and a fifth layer of opposite type conductivity disposed on said third layer to form a fourth P-N junction therebetween, said fifth layer having a portion defining an exposed surface providing a light recEiving surface, said portion being of lesser thickness than said fourth layer; said third layer having a portion encircling said fifth layer; a gate electrode disposed in ohmic contact with adjacent portions of said fifth and third layers to electrically bridge the latter, a first main electrode disposed in ohmic contact with the surface of said first layer, and a second main electrode disposed in ohmic contact with the surface of said fourth layer.
Claim 3
Dependent Claim
36 words
A light activated thyristor as claimed in claim 1 wherein a distance between said second P-N junction and said fourth P-N junction is smaller than that between said second P-N junction and said third P-N junction.
Claim 4
Dependent Claim
22 words
A light activated thyristor as claimed in claim 2 wherein said fifth layer is higher in impurity concentration than said fourth layer.
Claim 5
Dependent Claim
23 words
A light activated thyristor as claimed in claim 1 wherein said fifth layer is positioned on the central portion of said third layer.
Claim 6
Dependent Claim
36 words
A light activated thyristor as claimed in claim 4 wherein a distance between said second P-N junction and said fourth P-N junction is smaller than that between said second P-N junction and said third P-N junction.
Claim 7
Dependent Claim
22 words
A light activated thyristor as claimed in claim 5 wherein said fifth layer is higher in impurity concentration than said fourth layer.
References Cited (Backward Citations)
US3476989A
Cited
US3489962A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-10-10 | 1976-04-10 | 1976-10-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-10 | 1980-04-10 | 1980-10-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-10 | 1984-04-10 | 1984-10-10 | $7700.00 | Window Closed / Lapsed |