Patent US5303221A successfully refreshed from Google Patents.
US5303221A
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Optical pickup for an optical disc reproducing system
Assignee: Pioneer Corp
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Filing: 1993-06-08
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Granted: 1994-04-12
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Expires: 2013-06-08
Abstract
Abstract An optical pickup has a light source for generating a first light having a longer wavelength and a second light having a shorter wavelength, an objective, and a phase hologram disposed between the light source and the objective. The objective is designed to have a larger spherical aberration for the first light than a spherical aberration for the second light. The phase hologram is arranged to give a phase difference of an integer multiple of 2π for the second light. The phase hologram is further arranged so that a spherical aberration given to the first light has an opposite polarity to the polarity of the spherical aberration given by the objective.
Inventors
- 👤 Takanori Maeda
- 👤 Noriaki Murao
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 15:58
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/12; G11B7/135; G11B7/1353; G11B2007/0003; G11B2007/0006
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
161 words
An optical pickup for an optical disc reproducing system, comprising a light source for generating a first light having a first wavelength and a second light having a second wavelength; wherein the first wavelength is longer than the second wavelength, a focusing lens assembly for focusing the first and second lights on the optical disc, respectively, and a phase hologram disposed between the light source and the focusing lens assembly; wherein the focusing lens assembly has a spherical aberration coefficient for the first light larger than a spherical aberration coefficient for the second light; and the phase hologram corrects a phase difference of the second light by providing a phase difference of an integer multiple of 2π to the phase difference of the second light, and corrects a spherical aberration coefficient of the first light by providing the spherical aberration coefficient of the first light an opposite polarity to a polarity of the spherical aberration coefficient of the focusing lens assembly.
Claim 2
Dependent Claim
161 words
An optical pickup for an optical disc reproducing system, comprising a light source for generating a first light having a first wavelength and a second light having a second wavelength; wherein the first wavelength is longer than the second wavelength, a focusing lens assembly for focusing the first and second lights on the optical disc, respectively, and a phase hologram disposed between the light source and the focusing lens assembly; wherein the focusing lens assembly has a spherical aberration coefficient for the first light larger than a spherical aberration coefficient for the second light; and the phase hologram corrects a phase difference of the second light by providing a phase difference of an integer multiple of 2π to the phase difference of the second light, and corrects a spherical aberration coefficient of the first light by providing the spherical aberration coefficient of the first light an opposite polarity to a polarity of the spherical aberration coefficient of the focusing lens assembly.
References Cited (Backward Citations)
US5208801A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-04-11 | 1997-10-11 | 1998-04-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-04-11 | 2001-10-11 | 2002-04-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-04-11 | 2005-10-11 | 2006-04-12 | $7700.00 | Window Closed / Lapsed |