Patent US4643516A successfully refreshed from Google Patents.
US4643516A
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Laser beam scanning apparatus
Assignee: Ricoh Co Ltd
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Filing: 1983-02-03
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Granted: 1987-02-17
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Expires: 2003-02-03
Abstract
Abstract In laser beam scanning by a rotating polygonal mirror, a hologram scanner, etc., a cylindrical lens having a refractive power in a sub-scanning direction is introduced to place the beam deflecting surface and the scanning surface in a geometrical-optically conjugative relation, in order to prevent occurrence of a deviation in position of scanning line due to a deviation of the beam deflecting surface. However, in a Gauss beam such as a laser beam, a beam waist is not produced in a geometrical-optical conjugate point. This relation is utilized to select optical elements whereby apparatus may be miniaturized and the size of the beam spot may be adjusted.
Inventors
- 👤 Yukio Ogura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 23:33
CPC Classifications
G; G02; G02B; G02B26/00; G02B26/08; G02B26/10; G02B26/106
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
162 words
A light beam scanning apparatus comprising a semi-conductor laser, a coupling lens for forming a beam from said laser into a substantially parallel beam, a beam deflector, and a focussing lens for condensing beams on a scanning surface, wherein first and second cylindrical lenses having a refractive power only in a sub-scanning direction are disposed between said coupling lens and a deflecting surface of the deflector and between the focussing lens and the scanning surface, respectively, and said deflecting surface and said scanning surface are in a geometrical-optically conjugative relation with respect to the coupling lens and said second cylindrical lens, the improvement wherein said first cylindrical lens comprises a positive lens and negative cylindrical lens, the spacing between which is variable to each other, a prism having a refractive power within a main scanning direction is disposed between said coupling lens and deflecting surface, and a beam spot size may be adjusted independently in the main scanning direction and sub-scanning direction.
Claim 2
Dependent Claim
162 words
A light beam scanning apparatus comprising a semi-conductor laser, a coupling lens for forming a beam from said laser into a substantially parallel beam, a beam deflector, and a focussing lens for condensing beams on a scanning surface, wherein first and second cylindrical lenses having a refractive power only in a sub-scanning direction are disposed between said coupling lens and a deflecting surface of the deflector and between the focussing lens and the scanning surface, respectively, and said deflecting surface and said scanning surface are in a geometrical-optically conjugative relation with respect to the coupling lens and said second cylindrical lens, the improvement wherein said first cylindrical lens comprises a positive lens and negative cylindrical lens, the spacing between which is variable to each other, a prism having a refractive power within a main scanning direction is disposed between said coupling lens and deflecting surface, and a beam spot size may be adjusted independently in the main scanning direction and sub-scanning direction.
References Cited (Backward Citations)
US3853406A
Cited
JPS5588016A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-02-16 | 1990-08-18 | 1991-02-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-02-16 | 1994-08-18 | 1995-02-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-02-16 | 1998-08-18 | 1999-02-17 | $7700.00 | Window Closed / Lapsed |