US5144483A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Diffractive multifocal optical device
Assignee: CooperVision International Ltd
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Filing: 1991-04-17
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Granted: 1992-09-01
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Expires: 2011-04-17
Abstract
Abstract A bifocal lens of the Cohen lens design utilizing phase zone plate optics and a facet depth of one-half wavelength of the design wavelength, where the primary focal points are at two orders, specifically the 0 th and 1 st orders, and the brightness at each primary focal point is equal at about 0.40.
Inventors
- 👤 Allen L. Cohen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 22:17
CPC Classifications
A; A61; A61F; A61F2/00; A61F2/02; A61F2/14; A61F2/16; A61F2/1613; A61F2/1616; A61F2/1618; A61F2/1654; A61F2/1656; G; G02; G02B; G02B5/00; G02B5/18; G02B5/1876; G02C; G02C7/00; G02C7/02; G02C7/04; G02C7/041; G02C7/042; G02C7/044; G02C7/06; G02C2202/00; G02C2202/20
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
55 words
A multiple focal point profiled phase plate having a plurality of annular concentric zones in which a repetitive step with an optical path length equal to one-half wavelength is incorporated into the profile between blazed facets to provide two focal points of substantially equal brightness of about 40% of the intensity of the incident light.
Claim 2
Dependent Claim
55 words
A multiple focal point profiled phase plate having a plurality of annular concentric zones in which a repetitive step with an optical path length equal to one-half wavelength is incorporated into the profile between blazed facets to provide two focal points of substantially equal brightness of about 40% of the intensity of the incident light.
Claim 3
Dependent Claim
26 words
A multiple focal point profiled phase plate according to claim 1 wherein said blazed facets cause said two focal points to occur at adjacent diffractive orders.
Claim 4
Dependent Claim
21 words
A multiple focal point profiled phase plate according to claim 2 wherein said adjacent orders are the 0th and 1st orders.
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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) | 1995-09-01 | 1996-03-02 | 1996-09-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-09-01 | 2000-03-02 | 2000-09-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-09-01 | 2004-03-02 | 2004-09-01 | $7700.00 | Window Closed / Lapsed |