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Patent US4830481A successfully refreshed from Google Patents.
US4830481A
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US
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Multifocal diffractive lens
Assignee: 3M Co
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Filing: 1988-08-12
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Granted: 1989-05-16
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Expires: 2008-08-12
Abstract
Abstract A multifocal ophthalmic lens has a plurality of concentric diffractive zones with adjacent zones separated by steps having predetermined heights. Each step has an outer corner and each outer corner has a radius of curvature equal to at least one half the height of the step associated therewith.
Inventors
- 👤 John A. Futhey
- 👤 William B. Isaacson
- 👤 Ricky L. Neby
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 09:13
CPC Classifications
G; G02; G02C; G02C7/00; G02C7/02; G02C7/06; G02B; G02B5/00; G02B5/18; G02B5/1876; G02B5/189; G02B5/1895
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
54 words
A multi-focal ophthalmic lens having diffractive power, said lens having a plurality of concentric diffractive zones, said zones being separated by steps, said steps having predetermined heights, each step having an outer corner and each outer corner having a radius of curvature equal to at least one half said height of its associated step.
Claim 2
Dependent Claim
54 words
A multi-focal ophthalmic lens having diffractive power, said lens having a plurality of concentric diffractive zones, said zones being separated by steps, said steps having predetermined heights, each step having an outer corner and each outer corner having a radius of curvature equal to at least one half said height of its associated step.
Claim 3
Dependent Claim
14 words
The multi-focal ophthalmic lens of claim 1 wherein said lens is a contact lens.
Claim 4
Dependent Claim
26 words
The multi-focal ophthalmic lens of claim 1 wherein each outer corner has a radius of curvature equal to at least the height of its associated step.
Claim 5
Dependent Claim
14 words
The multi-focal ophthalmic lens of claim 3 wherein said lens is a contact lens.
Claim 6
Dependent Claim
27 words
The multi-focal ophthalmic lens of claim 3 wherein each outer corner has a radius of curvature equal to at least twice the height of its associated step.
Claim 7
Dependent Claim
14 words
The multi-focal ophthalmic lens of claim 5 wherein said lens is a contact lens.
Claim 8
Dependent Claim
36 words
The multi-focal ophthalmic lens of claim 1 wherein each step has an inner corner and each inner corner has a radius of curvature equal to at least one half of the height of its associated step.
Claim 9
Dependent Claim
14 words
The multi-focal ophthalmic lens of claim 7 wherein said lens is a contact lens.
Claim 10
Dependent Claim
25 words
The multi-focal contact lens of claim 8 wherein each inner corner has a radius of curvature equal to at least the height of its associated.
Claim 11
Dependent Claim
26 words
The multi-focal contact lens of claim 9 wherein each outer corner has a radius of curvature equal to at least the height of its associated step.
Claim 12
Dependent Claim
26 words
The multi-focal contact lens of claim 9 wherein each inner corner has a radius of curvature equal to at least twice the height of its associated.
Claim 13
Dependent Claim
27 words
The multi-focal contact lens of claim 11 wherein each outer corner has a radius of curvature equal to at least twice the height of its associated step.
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) | 1992-05-15 | 1992-11-14 | 1993-05-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-05-15 | 1996-11-14 | 1997-05-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-05-15 | 2000-11-14 | 2001-05-16 | $7700.00 | Window Closed / Lapsed |