US4635244A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical beam shaping system
Assignee: Ricoh Co Ltd
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Filing: 1985-07-05
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Granted: 1987-01-06
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Expires: 2005-07-05
Abstract
Abstract An optical system includes a semiconductor laser for emitting a laser beam, a coupling lens for converting the laser beam a parallel beam, an optical beam shaping system for increasing the diameter of the parallel beam in a direction in which the semiconductor laser has a smaller far field pattern, and an objective lens for focusing a beam shaped by the optical beam shaping system into a spot. To make the spot substantially circular in shape and increase the light utilization efficiency, the magnification of the optical beam shaping system in a direction parallel to the junction plane of the semiconductor laser is selected to fall in a certain range.
Inventors
- 👤 Hiroshi Gotoh
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 14:59
CPC Classifications
G; G02; G02B; G02B27/00; G02B27/09; G02B19/00; G02B19/0004; G02B19/0009; G02B19/0014; G02B19/0033; G02B19/0047; G02B19/0052; G02B27/0938; G02B27/095; G02B27/0955; G02B27/0966; G02B27/0972; G11; G11B; G11B7/00; G11B7/12; G11B7/135; G11B7/1372; G11B7/1378; G11B7/1398
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
134 words
An optical system comprising a semiconductor laser for emitting a laser beam, a coupling lens for converting the laser beam a parallel beam, an optical beam shaping system for increasing the diameter of the parallel beam in a direction in which said semiconductor laser has a smaller far field pattern, and an objective lens for focusing a beam shaped by said optical beam shaping system into a spot, said optical beam shaping system having a magnification selected to fall in the following range: ##EQU4## where M: magnification of the optical beam shaping system; fc: focal length of the coupling lens; θ//: divergent angle of the laser beam in a direction parallel to the junction plane of the semiconductor laser; fo: focal length of the objective lens; and NAo: numerical aperture of the objective lens.
Claim 2
Dependent Claim
134 words
An optical system comprising a semiconductor laser for emitting a laser beam, a coupling lens for converting the laser beam a parallel beam, an optical beam shaping system for increasing the diameter of the parallel beam in a direction in which said semiconductor laser has a smaller far field pattern, and an objective lens for focusing a beam shaped by said optical beam shaping system into a spot, said optical beam shaping system having a magnification selected to fall in the following range: ##EQU4## where M: magnification of the optical beam shaping system; fc: focal length of the coupling lens; θ//: divergent angle of the laser beam in a direction parallel to the junction plane of the semiconductor laser; fo: focal length of the objective lens; and NAo: numerical aperture of the objective lens.
Claim 3
Dependent Claim
15 words
An optical system according to claim 1, wherein said coupling lens comprises a convex lens.
Claim 4
Dependent Claim
33 words
An optical system according to claim 1, wherein said optical beam shaping system comprises a divergent cylindrical lens closer to said coupling lens and a convergent cylindrical lens closer to said objective lens.
Claim 5
Dependent Claim
21 words
An optical system according to claim 1, including an optical information storage disk disposed in confronting relation to said objective lens.
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) | 1990-01-05 | 1990-07-07 | 1991-01-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-01-05 | 1994-07-07 | 1995-01-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-01-05 | 1998-07-07 | 1999-01-06 | $7700.00 | Window Closed / Lapsed |