US5428588A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical head
Assignee: Ricoh Co Ltd
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Filing: 1993-09-15
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Granted: 1995-06-27
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Expires: 2013-09-15
Abstract
Abstract The present invention relates to an optical head for recording, reproducing and erasing data on an optical data recording medium. The optical head has a fixed optical system having a laser optical source for emitting a light and a signal detecting optical system for detecting an error signal. A movable optical system having a beam splitter provided with a prism boundary face and having an objective at a position thereof opposing a surface of the optical data recording medium for receiving the emitted light through the beam splitter and focusing the received light onto the surface of the optical data recording medium as an optical spot. The beam splitter has, at the prism boundary face thereof, a polarizing film for transmitting one portion of the emitted light from the laser light source. The beam splitter has, at one side face thereof, reflective face for reflecting one portion of or all of the transmitted light through the polarizing film, and has, at another side face thereof, a light receiving element thereof for receiving the reflected light from the reflective face and one portion of said reflected light from the surface of the optical data recording medium.
Inventors
- 👤 Shigeru Ohuchida
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 06:42
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/12; G11B7/135; G11B7/1356; G11B7/08; G11B7/09; G11B7/094
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
202 words
An optical head for recording, reproducing and erasing data on an optical data recording medium, comprising: a fixed optical system having a laser optical source for emitting a light, and a signal detecting optical system for detecting an error signal; and a movable optical system having a beam splitter provided with a prism boundary face, and an objective at a position thereof opposing a surface of said optical data recording medium, said objective for receiving said emitted light from said laser light source through said beam splitter and focusing said received light on to said surface of said optical data recording medium as an optical spot; said beam splitter having at said prism boundary face thereof a polarizing film for transmitting one portion of said emitted light from said laser light source, having at one side face thereof a reflective face for reflecting one portion of or all of said transmitted light through said polarizing film, and having at another side face thereof a light receiving element for receiving both of said reflected light from said reflective face and one portion of said reflected light from said surface of said optical data recording medium to cancel an offset of an optical axis.
Claim 2
Dependent Claim
202 words
An optical head for recording, reproducing and erasing data on an optical data recording medium, comprising: a fixed optical system having a laser optical source for emitting a light, and a signal detecting optical system for detecting an error signal; and a movable optical system having a beam splitter provided with a prism boundary face, and an objective at a position thereof opposing a surface of said optical data recording medium, said objective for receiving said emitted light from said laser light source through said beam splitter and focusing said received light on to said surface of said optical data recording medium as an optical spot; said beam splitter having at said prism boundary face thereof a polarizing film for transmitting one portion of said emitted light from said laser light source, having at one side face thereof a reflective face for reflecting one portion of or all of said transmitted light through said polarizing film, and having at another side face thereof a light receiving element for receiving both of said reflected light from said reflective face and one portion of said reflected light from said surface of said optical data recording medium to cancel an offset of an optical axis.
Claim 3
Dependent Claim
55 words
An optical head according to claim 1, wherein said reflective face is inclined in such a manner that an optical path of said reflected light from said reflective face of said beam splitter is not parallel to an optical path of a reflected light from said optical disc which advances toward said fixed optical system.
Claim 4
Dependent Claim
30 words
An optical head according to claim 1, wherein said beam splitter further includes a 1/4 wavelength plate between said one side face of said beam splitter and said reflective face.
Claim 5
Dependent Claim
149 words
An optical head for recording, reproducing and erasing data on an optical data recording medium, comprising: a fixed optical system having a laser optical source for emitting a light, and a signal detecting optical system for detecting an error signal; and a movable optical system having a beam splitter for transmitting one portion of said emitted light from said laser optical source, having an objective at a position thereof opposing a surface of said optical data recording medium, said objective for receiving said emitted light from said laser optical source through said beam splitter and focusing said received light onto said surface of said optical data recording medium as an optical spot, and having a light receiving element for receiving the other portion of said emitted light from said laser optical source to detect an offset of an optical axis at an optical path passing through said beam splitter.
Claim 6
Dependent Claim
149 words
An optical head for recording, reproducing and erasing data on an optical data recording medium, comprising: a fixed optical system having a laser optical source for emitting a light, and a signal detecting optical system for detecting an error signal; and a movable optical system having a beam splitter for transmitting one portion of said emitted light from said laser optical source, having an objective at a position thereof opposing a surface of said optical data recording medium, said objective for receiving said emitted light from said laser optical source through said beam splitter and focusing said received light onto said surface of said optical data recording medium as an optical spot, and having a light receiving element for receiving the other portion of said emitted light from said laser optical source to detect an offset of an optical axis at an optical path passing through said beam splitter.
Claim 7
Dependent Claim
37 words
An optical head according to claim 4, wherein said light receiving element for correcting the offset of the optical axis is arranged in said optical path passing through said beam splitter, but outside said movable optical system.
Claim 8
Dependent Claim
42 words
An optical head according to claim 4, wherein said beam splitter is provided on one face thereof with a total reflection prism for reflecting said emitted light from said laser optical source and causing said reflected light to enter said beam splitter.
Claim 9
Dependent Claim
175 words
An optical head for recording reproducing and erasing data on an optical data recording medium, comprising: a fixed optical system having a laser optical source for emitting a light, and a signal detecting optical system for detecting an error signal; and a movable optical system having a beam splitter provided with an inclined reflective face for reflecting one portion of said emitted light from said laser optical source at a different angle from said emitted light without reflecting said emitted light to said optical data recording medium having an objective at a position thereof opposing a surface of said optical data recording medium said objective for receiving said emitted light from said laser light source through said beam splitter and focusing said received light onto said surface of said optical data recording medium as an optical spot, said signal detecting optical system further including a light receiving element for receiving said light which is reflected on said inclined reflective face and returns to said fixed optical system to detect an offset of an optical axis.
Claim 10
Dependent Claim
175 words
An optical head for recording reproducing and erasing data on an optical data recording medium, comprising: a fixed optical system having a laser optical source for emitting a light, and a signal detecting optical system for detecting an error signal; and a movable optical system having a beam splitter provided with an inclined reflective face for reflecting one portion of said emitted light from said laser optical source at a different angle from said emitted light without reflecting said emitted light to said optical data recording medium having an objective at a position thereof opposing a surface of said optical data recording medium said objective for receiving said emitted light from said laser light source through said beam splitter and focusing said received light onto said surface of said optical data recording medium as an optical spot, said signal detecting optical system further including a light receiving element for receiving said light which is reflected on said inclined reflective face and returns to said fixed optical system to detect an offset of an optical axis.
Claim 11
Dependent Claim
42 words
An optical head according to claim 7, wherein said beam splitter is provided on one face thereof with a total reflection prism for reflecting said emitted light from said laser optical source and causing said reflected light to enter said beam splitter.
References Cited (Backward Citations)
JPS63263637A
Cited
US5120136A
Cited
US5272685A
Cited
US5206852A
Cited
US5200946A
Cited
US5235574A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-06-26 | 1998-12-26 | 1999-06-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-06-26 | 2002-12-26 | 2003-06-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-06-26 | 2006-12-26 | 2007-06-27 | $7700.00 | Window Closed / Lapsed |