US4641929A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Biaspherical lens
Assignee: US Philips Corp
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Filing: 1985-01-07
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Granted: 1987-02-10
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Expires: 2005-01-07
Abstract
Abstract A single element lens having two aspherical refractive surfaces comprises a lens substrate and two layers of transparent plastic. Each layer has an aspherical outer profile. The lens substrate is a sphere and can be manufactured simply and cheaply.
Inventors
- 👤 Josephus J. M. Braat
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 22:19
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/12; G11B7/135; G11B7/1372; G11B7/1374; G02; G02B; G02B3/00; G02B3/02; G02B3/04
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
66 words
An lens having two aspheric refractive surfaces, said lens comprising: a lens substrate, said lens substrate being a sphere; and first and second layers of transparent plastic on the substrate, said first layer being arranged on a first side of the substrate, said second layer being arranged on a second side of the substrate opposite to the first side, each layer having an aspheric outer surface.
Claim 2
Dependent Claim
66 words
An lens having two aspheric refractive surfaces, said lens comprising: a lens substrate, said lens substrate being a sphere; and first and second layers of transparent plastic on the substrate, said first layer being arranged on a first side of the substrate, said second layer being arranged on a second side of the substrate opposite to the first side, each layer having an aspheric outer surface.
Claim 3
Dependent Claim
21 words
A lens as claimed in claim 1, characterized in that the substrate has a refractive index between approximately 1.45 and 1.65.
Claim 4
Dependent Claim
94 words
An optical scanning unit comprising: a radiation source which emits a diverging radiation beam; and an objective lens for focusing the diverging radiation beam to form a radiation spot on a surface to be scanned, said lens comprising: a lens substrate, said lens substrate being a sphere; and first and second layers of transparent plastic on the substrate, said first layer being arranged on a first side of the substrate, said second layer being arranged on a second side of the substrate opposite to the first side, each layer having an aspheric outer surface.
Claim 5
Dependent Claim
94 words
An optical scanning unit comprising: a radiation source which emits a diverging radiation beam; and an objective lens for focusing the diverging radiation beam to form a radiation spot on a surface to be scanned, said lens comprising: a lens substrate, said lens substrate being a sphere; and first and second layers of transparent plastic on the substrate, said first layer being arranged on a first side of the substrate, said second layer being arranged on a second side of the substrate opposite to the first side, each layer having an aspheric outer surface.
Claim 6
Dependent Claim
23 words
An optical scanning unit as claimed in claim 3, characterized in that the substrate has a refractive index between approximately 1.45 and 1.65.
Claim 7
Dependent Claim
26 words
An optical scanning unit as claimed in claim 3, characterized in that the unit has no radiation collecting element between the radiation source and the lens.
Claim 8
Dependent Claim
23 words
An optical scanning unit as claimed in claim 5, characterized in that the substrate has a refractive index between approximately 1.45 and 1.65.
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) | 1990-02-09 | 1990-08-11 | 1991-02-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-02-09 | 1994-08-11 | 1995-02-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-02-09 | 1998-08-11 | 1999-02-10 | $7700.00 | Window Closed / Lapsed |