Patent US3700947A successfully refreshed from Google Patents.
US3700947A
Expired / Lapsed
US
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Increased sensitivity photocathode structure
Assignee: Bendix Corp
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Filing: 1971-04-08
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Granted: 1972-10-24
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Expires: 1991-04-08
Abstract
Abstract A photocathode substrate includes a plurality of prisms to refract radiation before it impinges upon a photocathode material. The refraction causes most of the radiation to meet the photocathode material at an angle other than 90* so that internal reflection of the energy within the photocathode material occurs. This greatly enhances the probability of electrons being released from the photocathode material.
Inventors
- 👤 George W Goodrich
- 👤 William B Colson
- 👤 Calvin C Matle
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 17:10
CPC Classifications
H; H01; H01J; H01J40/00; H01J40/02; H01J40/04; H01J40/06
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
80 words
A photocathode structure for detecting radiation comprising: an input surface transparent to said radiation; a planar photocathode surface in the proximity of said input surface; a plurality of refractive elements interposed between said input surface and said photocathode surface, said refractive elements refracting radiation emerging from said input surface away from a perpendicular disposition with respect to said photocathode surface to increase internal reflection of said radiation and enhance the probability that electrons will be emitted by said photocathode surface.
Claim 2
Dependent Claim
80 words
A photocathode structure for detecting radiation comprising: an input surface transparent to said radiation; a planar photocathode surface in the proximity of said input surface; a plurality of refractive elements interposed between said input surface and said photocathode surface, said refractive elements refracting radiation emerging from said input surface away from a perpendicular disposition with respect to said photocathode surface to increase internal reflection of said radiation and enhance the probability that electrons will be emitted by said photocathode surface.
Claim 3
Dependent Claim
29 words
The photocathode structure of claim 1 wherein said refractive elements are longitudinal elements arranged in a parallel relationship so that substantially all of said radiation passes through said elements.
Claim 4
Dependent Claim
18 words
The photocathode structure of claim 2 wherein said refractive elements have an index of refraction greater than unity.
Claim 5
Dependent Claim
27 words
The photocathode structure of claim 2 wherein said refractive elements are longitudinal prisms, the bases of said prisms forming a planar surface for supporting said photocathode surface.
Claim 6
Dependent Claim
42 words
The photocathode structure of claim 4 wherein said input surface is supported by the apexes of said prisms; and including a second plurality of prisms between said longitudinal prisms, the index of refraction of said second plurality of prisms being approximately unity.
Claim 7
Dependent Claim
42 words
The photocathode structure of claim 5 wherein said longitudinal prisms are constructed in accordance with the constraint: (n2 - 1)1/2 cos Alpha - sin Alpha > 1 where: n index of refraction of the prisms Alpha half apex angle of the prisms.
Claim 8
Dependent Claim
50 words
The photocathode structure of claim 1 wherein said refractive elements are longitudinal prisms having a triangular cross-section, the apexes of said prisms supporting said input surface; a second plurality of prisms between said longitudinal prisms and said input surface, the index of refraction of said second prisms being approximately unity.
Claim 9
Dependent Claim
31 words
The photocathode structure of claIm 7 wherein said input surface has an index of refraction n1, said photocathode surface has an index of refraction n2 and n2 is greater than n1.
Claim 10
Dependent Claim
43 words
The photocathode structure of claim 7 wherein said longitudinal prisms are fabricated in accordance with the constraint: (n2 - 1)1/2 cos Alpha - sin Alpha > 1 where: n index of refraction of the longitudinal prisms Alpha half apex angle of longitudinal prisms.
Claim 11
Dependent Claim
22 words
The photocathode structure of claim 9 further including a support substrate interposed between said photocathode layer and the bases of said prisms.
Claim 12
Dependent Claim
41 words
The photocathode structure of claim 10 wherein said input surface and said support substrate are formed from glass, said second plurality of prisms are composed of air, and said longitudinal prisms have an index of refraction greater than Square Root 2.
References Cited (Backward Citations)
US2892096A
Cited
US3030514A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-10-24 | 1976-04-24 | 1976-10-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-24 | 1980-04-24 | 1980-10-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-24 | 1984-04-24 | 1984-10-24 | $7700.00 | Window Closed / Lapsed |