US4707085A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fθ lens for use in light beam scanner
Assignee: Ricoh Co Ltd
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Filing: 1986-01-24
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Granted: 1987-11-17
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Expires: 2006-01-24
Abstract
Abstract An fθ lens for use in a light beam scanner for deflecting a monochromatic or quasi-monochromatic light beam. The fθ lens comprises two positive-meniscus lenses having concave surfaces directed to a deflection point about which the light beam is deflected. The lenses have lens surfaces having radii of curvature R1, R2, R3, R4 in order from the deflection point, and have a combined focal length f, the fθ lens meeting the following conditions: ##EQU1##
Inventors
- 👤 Kenichi Takanashi
- 👤 Nobuo Sakuma
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 17:06
CPC Classifications
G; G02; G02B; G02B13/00; G02B13/0005
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
79 words
An fθ lens for use in a light beam scanner for deflecting a light beam, said fθ lens comprising: two positive-meniscus lenses having concave surfaces directed to a deflection point about which the light beam is deflected, said lenses having lens surfaces having radii of curvature R1, R2, R3, R4 in order from said deflection point, said lenses having a focal length f of the entire lens system as a whole, said fθ lens meeting the following conditions: ##EQU4##
Claim 2
Dependent Claim
79 words
An fθ lens for use in a light beam scanner for deflecting a light beam, said fθ lens comprising: two positive-meniscus lenses having concave surfaces directed to a deflection point about which the light beam is deflected, said lenses having lens surfaces having radii of curvature R1, R2, R3, R4 in order from said deflection point, said lenses having a focal length f of the entire lens system as a whole, said fθ lens meeting the following conditions: ##EQU4##
Claim 3
Dependent Claim
13 words
An fθ lens according to claim 1, wherein the light beam is monochromatic.
Claim 4
Dependent Claim
13 words
An fθ lens according to claim 1, wherein said light beam is quasi-monochromatic.
Claim 5
Dependent Claim
82 words
A light beam scanner comprising: a light beam source for producing a light beam; deflection means for deflecting said light beam in a scanning direction; an fθ lens including two positive-meniscus lenses having concave surfaces directed toward said deflecting means, saids lenses having lens surfaces with radii of curvature R1, R2, R3, R4 in order from said deflection means, said lenses having a focal length f of the entire lens system as a whole, said fθ lens meeting the following conditions: ##EQU5##
Claim 6
Dependent Claim
82 words
A light beam scanner comprising: a light beam source for producing a light beam; deflection means for deflecting said light beam in a scanning direction; an fθ lens including two positive-meniscus lenses having concave surfaces directed toward said deflecting means, saids lenses having lens surfaces with radii of curvature R1, R2, R3, R4 in order from said deflection means, said lenses having a focal length f of the entire lens system as a whole, said fθ lens meeting the following conditions: ##EQU5##
Claim 7
Dependent Claim
14 words
A light beam scanner according to claim 4, wherein said light beam is monochromatic.
Claim 8
Dependent Claim
14 words
A light beam scanner according to claim 4, wherein said light beam is quasi-monochromatic.
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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) | 1990-11-16 | 1991-05-18 | 1991-11-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-11-16 | 1995-05-18 | 1995-11-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-11-16 | 1999-05-18 | 1999-11-17 | $7700.00 | Window Closed / Lapsed |