US4464011A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Light beam scanning apparatus and the method
Assignee: Hitachi Ltd
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Filing: 1982-08-06
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Granted: 1984-08-07
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Expires: 2002-08-06
Abstract
Abstract A light beam scanning apparatus projects a light beam swept by a light scanner to a spherical mirror and scans by a light beam spot reflected and focused by the spherical mirror a surface of an object arranged to oppose to the spherical mirror at a position spaced from the spherical mirror by a distance equal to a focal distance f of the spherical mirror. An optical path length between the light scanner and the spherical mirror is set to 0.78 f-0.84 f to minimize a curvature of field (circle of confusion).
Inventors
- 👤 Kensaku Takahashi
- 👤 Yasuo Yatsugake
- 👤 Fukuo Iwaya
- 👤 Makoto Ito
- 👤 Katsumi Takami
- 👤 Kyo Suda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 07:15
CPC Classifications
G; G02; G02B; G02B26/00; G02B26/08; G02B26/10
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
100 words
A light beam scanning apparatus for projecting a light beam swept by a light scanner to a concave mirror and scanning by a light beam spot reflected and focused by said concave mirror a surface of an object arranged to oppose to said concave mirror at a position spaced from said concave mirror by a distance substantially equal to a focal distance f of said concave mirror; characterized in that said concave mirror is a spherical mirror and an optical path length between said light scanner and said spherical mirror is set between about 0.78 f and about 0.84 f.
Claim 2
Dependent Claim
100 words
A light beam scanning apparatus for projecting a light beam swept by a light scanner to a concave mirror and scanning by a light beam spot reflected and focused by said concave mirror a surface of an object arranged to oppose to said concave mirror at a position spaced from said concave mirror by a distance substantially equal to a focal distance f of said concave mirror; characterized in that said concave mirror is a spherical mirror and an optical path length between said light scanner and said spherical mirror is set between about 0.78 f and about 0.84 f.
Claim 3
Dependent Claim
32 words
A light beam scanning apparatus according to claim 1 further comprising a planar mirror for reflecting said light beam arranged in the optical path between said light scanner and said spherical mirror.
Claim 4
Dependent Claim
24 words
A light beam scanning apparatus according to claim 1 wherein said light scanner includes a fine adjusting mechanism for adjusting said optical path length.
Claim 5
Dependent Claim
95 words
A light beam scanning apparatus comprising: a source of substantially parallel light beam; a scanning means for angularly scanning said parallel light beam; a spherical mirror having a focal length f and disposed to receive said scanned parallel light beam at a position optically distanced from said scanning means by kf where k is between about 0.78 and about 0.84, so as to reflect said parallel light beam; an object plane disposed substantially optically normal to the reflected light beam at a position optically distanced substantially by the focal length f from said spherical mirror.
Claim 6
Dependent Claim
95 words
A light beam scanning apparatus comprising: a source of substantially parallel light beam; a scanning means for angularly scanning said parallel light beam; a spherical mirror having a focal length f and disposed to receive said scanned parallel light beam at a position optically distanced from said scanning means by kf where k is between about 0.78 and about 0.84, so as to reflect said parallel light beam; an object plane disposed substantially optically normal to the reflected light beam at a position optically distanced substantially by the focal length f from said spherical mirror.
Claim 7
Dependent Claim
28 words
A light beam scanning apparatus according to claim 4, wherein said scanning means, said spherical mirror and said object plane are so disposed to constitute an off-axis configuration.
Claim 8
Dependent Claim
29 words
A light beam scanning apparatus according to claim 5, further including a beam bender for bending said beam scanned by said scanning means and directed to said spherical mirror.
Claim 9
Dependent Claim
30 words
A light beam scanning apparatus according to claim 4, 5 or 6, wherein said source of light beam includes a laser source and said scanning means includes a rotating mirror.
Claim 10
Independent Claim
89 words
A method of scanning a light spot on an object plane comprising the steps of: generating a substantially parallel light beam; angularly scanning said parallel light beam; reflecting said parallel light beam by a spherical mirror having a focal length f, at a position optically distanced by kf from the point of scanning, where k is between about 0.78 and about 0.84; impinging said reflected light beam substantially optically normal to an object plane at a position optically distanced substantially by the focal length f from said spherical mirror.
Claim 11
Independent Claim
89 words
A method of scanning a light spot on an object plane comprising the steps of: generating a substantially parallel light beam; angularly scanning said parallel light beam; reflecting said parallel light beam by a spherical mirror having a focal length f, at a position optically distanced by kf from the point of scanning, where k is between about 0.78 and about 0.84; impinging said reflected light beam substantially optically normal to an object plane at a position optically distanced substantially by the focal length f from said spherical mirror.
References Cited (Backward Citations)
US4196961A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-08-07 | 1988-02-06 | 1988-08-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-08-07 | 1992-02-06 | 1992-08-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-08-07 | 1996-02-06 | 1996-08-07 | $7700.00 | Window Closed / Lapsed |