US4989959A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Anti-aliasing optical system with pyramidal transparent structure
Assignee: Polaroid Corp
•
Filing: 1989-06-12
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Granted: 1991-02-05
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Expires: 2009-06-12
Abstract
Abstract Optical, low-pass filter, anti-aliasing apparatus for an array of photosensor elements is a substantially wavelength independent optical, low-pass phase filter formed from a substantially transparent, convex or concave pyramidal structure.
Inventors
- 👤 William T. Plummer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 22:49
CPC Classifications
G; G02; G02B; G02B27/00; G02B27/42; G02B27/46
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
73 words
An optical, low-pass filter, anti-aliasing apparatus comprising: an objective lens for forming an image; and a pyramidal structure fabricated of a substantially transparent material and located at or near the aperture stop of said objective lens or at or near its image to create a multiplicity of overlapping object images for the purpose of providing the low-pass filtering, said low-pass filtering remaining substantially constant as the aperture size of said objective lens changes.
Claim 2
Dependent Claim
73 words
An optical, low-pass filter, anti-aliasing apparatus comprising: an objective lens for forming an image; and a pyramidal structure fabricated of a substantially transparent material and located at or near the aperture stop of said objective lens or at or near its image to create a multiplicity of overlapping object images for the purpose of providing the low-pass filtering, said low-pass filtering remaining substantially constant as the aperture size of said objective lens changes.
Claim 3
Dependent Claim
20 words
The optical, anti-aliasing apparatus of claim 1 wherein the pyramidal structure is a concave structure comprised of four wedge-like depressions.
Claim 4
Dependent Claim
33 words
The optical, anti-aliasing apparatus of claim 2 wherein the angles of the wedge-like depressions are predetermined to offset the light passing therethrough by an amount sufficient to provide a predetermined low-pass filter function.
Claim 5
Dependent Claim
22 words
The optical, anti-aliasing apparatus of claim 1 further comprising an array of photosensing elements located in the imaging plane of said apparatus.
Claim 6
Dependent Claim
21 words
The optical, anti-aliasing apparatus of claim 4 wherein said pyramidal structure comprises wedge-like protrusions and said transparent material comprises barium fluoride.
Claim 7
Dependent Claim
21 words
The optical anti-aliasing apparatus of claim 4 wherein said pyramidal structure comprises wedge-like protrusions and said transparent material comprises magnesium fluoride.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-02-04 | 1994-08-06 | 1995-02-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-02-04 | 1998-08-06 | 1999-02-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-02-04 | 2002-08-06 | 2003-02-05 | $7700.00 | Window Closed / Lapsed |