Patent US4477148A successfully refreshed from Google Patents.
US4477148A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical low-pass filter
Assignee: Canon Inc
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Filing: 1982-05-12
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Granted: 1984-10-16
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Expires: 2002-05-12
Abstract
Abstract An optical low-pass filter is comprized of micro stripe prisms arranged on the surface of a transparent member. A transmissive medium which is of different refractive index from that of air is used to fill the grooves of the microprisms to permit the arrangement to have micro stripe prisms with a large vertex angle.
Inventors
- 👤 Sadahiko Tsuji
- 👤 Akira Tajima
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 09:30
CPC Classifications
G; G02; G02B; G02B5/00; G02B5/04; G02B5/045; G02B27/00; G02B27/42; G02B27/46; G02B5/18; G02B5/1866; G02B5/1871
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
99 words
An optical low-pass filter comprising: (a) first and second transmission members respectively having a stripe micro prism formed on one surface thereof, said micro prism of the first transmission member having a shape different from that of the micro prism of the second transmission member; and (b) a transmissive layer provided between the micro prism surface of the first transmission member and the micro prism surface of the second transmission member, said transmissive layer filling up a space between the first and second transmission members and consisting of an adhesive having a refractive index different from that of air.
Claim 2
Dependent Claim
99 words
An optical low-pass filter comprising: (a) first and second transmission members respectively having a stripe micro prism formed on one surface thereof, said micro prism of the first transmission member having a shape different from that of the micro prism of the second transmission member; and (b) a transmissive layer provided between the micro prism surface of the first transmission member and the micro prism surface of the second transmission member, said transmissive layer filling up a space between the first and second transmission members and consisting of an adhesive having a refractive index different from that of air.
Claim 3
Dependent Claim
34 words
An optical low-pass filter according to claim 1, wherein the vertex angle of the micro prism of the first transmission member is different from that of the micro prism of the second transmission member.
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) | 1987-10-16 | 1988-04-16 | 1988-10-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-10-16 | 1992-04-16 | 1992-10-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-10-16 | 1996-04-16 | 1996-10-16 | $7700.00 | Window Closed / Lapsed |