US5600620A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical head apparatus having means to eliminate noise caused by side-lobes
Assignee: NEC Corp
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Filing: 1995-11-08
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Granted: 1997-02-04
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Expires: 2015-11-08
Abstract
Abstract An optical head apparatus includes a light source, an optical modulation unit, an objective lens, a reflected beam condensing unit, and a photodetection unit. The light source emits a light beam. The optical modulation unit modulates one of a light intensity and a phase in a section of the light beam from the light source and adjusts a generation position of a side lobe light beam of the light beam. The optical modulation unit has at least a first strip-like light-shielding area inclined by a first predetermined angle with respect to a vertical axis in the section of the light beam. The objective lens focuses the light beam from the optical modulation unit to form a small spot on a recording medium. The reflected beam condensing unit condenses a reflected beam from the small spot on the recording medium. The photodetection unit detects the reflected beam from the reflected beam condensing unit to reproduce information.
Inventors
- 👤 Osamu Ohguri
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 11:34
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/12; G11B7/135; G11B7/1381; G11B7/1356; G11B7/1359; G11B7/1392
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
142 words
An optical head apparatus comprising: a light source for emitting a light beam; optical modulation means for modulating one of a light intensity and a phase in a section of the light beam from said light source and controlling the position of a generated side lobe light beam, said optical modulation means having at least a first strip-like light-shielding area rotated about the light beam propagation direction by a first predetermined angle with respect to a vertical axis in the section of the light beam; an objective lens for focusing the light beam from said optical modulation means to form a super-resolution light spot on a recording medium; reflected beam condensing means for condensing a reflected beam from the small spot on said recording medium; and photodetection means for detecting the reflected beam from said reflected beam condensing means to reproduce information.
Claim 2
Dependent Claim
142 words
An optical head apparatus comprising: a light source for emitting a light beam; optical modulation means for modulating one of a light intensity and a phase in a section of the light beam from said light source and controlling the position of a generated side lobe light beam, said optical modulation means having at least a first strip-like light-shielding area rotated about the light beam propagation direction by a first predetermined angle with respect to a vertical axis in the section of the light beam; an objective lens for focusing the light beam from said optical modulation means to form a super-resolution light spot on a recording medium; reflected beam condensing means for condensing a reflected beam from the small spot on said recording medium; and photodetection means for detecting the reflected beam from said reflected beam condensing means to reproduce information.
Claim 3
Dependent Claim
21 words
An apparatus according to claim 1, wherein said optical modulation means has an elongated light-shielding plate as the first light-shielding area.
Claim 4
Dependent Claim
32 words
An apparatus according to claim 1, wherein said optical modulation means has a second strip-like light-shielding area crossing the first light-shielding area near a center of the section of the light beam.
Claim 5
Dependent Claim
22 words
An apparatus according to claim 3, wherein said optical modulation means has X-shaped light-shielding plates as the first and second light-shielding areas.
Claim 6
Dependent Claim
30 words
An apparatus according to claim 1, wherein said optical modulation means is constituted by a light intensity modulator for modulating the intensity of the light beam from the laser source.
Claim 7
Dependent Claim
40 words
An apparatus according to claim 1, wherein said optical modulation means is constituted by a light phase modulator for modulating the light beam from said laser source such that a phase difference between incident light and exit light becomes π.
Claim 8
Dependent Claim
39 words
An apparatus according to claim 1, further comprising an optical filter, arranged between said reflected beam condensing means and said photodetection means, for shielding the side lobe light beams of the reflected beam from said reflected beam condensing means.
Claim 9
Dependent Claim
30 words
An apparatus according to claim 7, wherein said optical filter has a slit-like transmission area crossing the first light-shielding area of said optical modulation means at a second predetermined angle.
Claim 10
Dependent Claim
59 words
An apparatus according to claim 8, wherein the first light-shielding area of said optical modulation means is inclined by 45° with respect to the vertical axis as the first predetermined angle, and the transmission area of said optical filter crosses the first light-shielding area at a pitch corresponding to an integer multiple of 45° as the second predetermined angle.
Claim 11
Dependent Claim
23 words
An apparatus according to claim 7, wherein said optical filter has a pinhole-like transmission area substantially matching the section of the light beam.
Claim 12
Dependent Claim
165 words
An optical head apparatus comprising: a laser source for emitting a laser beam as a light beam; optical modulation means for modulating one of a light intensity and a phase in a section of the light beam from said laser source and controlling the position of a generated side lobe light beam, said optical modulation means having an elongated reflecting plate rotated about the light beam propagation direction by a predetermined angle with respect to a vertical axis in the section of the light beam; an objective lens for focusing the light beam from said optical modulation means to form a super-resolution light spot on a recording medium; reflected beam condensing means for condensing a reflected beam from the small spot on said recording medium; an optical filter for transmitting a main beam of the reflected beam from said reflected beam condensing means and shielding the side lobe light beam; and photodetection means for detecting the reflected beam from said optical filter to reproduce information.
Claim 13
Dependent Claim
165 words
An optical head apparatus comprising: a laser source for emitting a laser beam as a light beam; optical modulation means for modulating one of a light intensity and a phase in a section of the light beam from said laser source and controlling the position of a generated side lobe light beam, said optical modulation means having an elongated reflecting plate rotated about the light beam propagation direction by a predetermined angle with respect to a vertical axis in the section of the light beam; an objective lens for focusing the light beam from said optical modulation means to form a super-resolution light spot on a recording medium; reflected beam condensing means for condensing a reflected beam from the small spot on said recording medium; an optical filter for transmitting a main beam of the reflected beam from said reflected beam condensing means and shielding the side lobe light beam; and photodetection means for detecting the reflected beam from said optical filter to reproduce information.
Claim 14
Dependent Claim
153 words
An optical head apparatus comprising: a laser source for emitting a laser beam as a light beam; optical modulation means for modulating one of a light intensity and a phase in a section of the light beam from said laser source and controlling the position of a generated side lobe light beam, said optical modulation means having X-shaped reflecting plates crossing each other near a center of the section of the light beam; an objective lens for focusing the light beam from said optical modulation means to form a super-resolution light spot on a recording medium; reflected beam condensing means for condensing a reflected beam from the small spot on said recording medium; an optical filter for transmitting a main beam of the reflected beam from said reflected beam condensing means and shielding the side lobe light beam; and photodetection means for detecting the reflected beam from said optical filter to reproduce information.
Claim 15
Dependent Claim
153 words
An optical head apparatus comprising: a laser source for emitting a laser beam as a light beam; optical modulation means for modulating one of a light intensity and a phase in a section of the light beam from said laser source and controlling the position of a generated side lobe light beam, said optical modulation means having X-shaped reflecting plates crossing each other near a center of the section of the light beam; an objective lens for focusing the light beam from said optical modulation means to form a super-resolution light spot on a recording medium; reflected beam condensing means for condensing a reflected beam from the small spot on said recording medium; an optical filter for transmitting a main beam of the reflected beam from said reflected beam condensing means and shielding the side lobe light beam; and photodetection means for detecting the reflected beam from said optical filter to reproduce information.
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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) | 2000-02-04 | 2000-08-05 | 2001-02-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-02-04 | 2004-08-05 | 2005-02-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-02-04 | 2008-08-05 | 2009-02-04 | $7700.00 | Window Closed / Lapsed |