US5155616A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Scanning optical system
Assignee: Ricoh Co Ltd
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Filing: 1991-10-29
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Granted: 1992-10-13
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Expires: 2011-10-29
Abstract
Abstract A scanning optical system has a light source for emitting a light beam; a condenser lens for changing the light beam from the light source to a parallel light beam; a connection holding member for supporting the light source and the condenser lens; a deflector for deflecting an approximately parallel light beam transmitted from the condenser lens at an equiangular velocity; and a lens for optical scanning for scanning a scanned face at an approximately equal speed while converging the light beam deflected by the deflector and forming an image in the shape of a spot on the scanned face, the lens for optical scanning being formed by a plastic material for optics. This scanning optical system is constructed such that a coefficient of linear expansion of the connection holding member, a focal length of the condenser lens, a focal length, a refractive index and a coefficient of linear expansion of the lens for optical scanning, and a change in refractive index of the lens for optical scanning with respect to the change in environmental temperature satisfy a predetermined condition. Another condition using other parameters with respect to the lens optical system may be set.
Inventors
- 👤 Katsumi Yamaguchi
- 👤 Nobuo Sakuma
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 01:12
CPC Classifications
G; G02; G02B; G02B13/00; G02B13/0005; G02B26/00; G02B26/08; G02B26/10; G02B26/12
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
245 words
A scanning optical system comprising: a light source for emitting a light beam; a condenser lens for changing the light beam from the light source to a convergent light beam; a connection holding member for supporting the light source and the condenser lens; a deflector for deflecting the convergent light beam transmitted from said condenser lens at an equiangular velocity; and a single lens for optical scanning for scanning a scanned face at an approximately equal speed while further converging the convergent light beam deflected by the deflector and forming an image in the shape of a spot on the scanned face, said lens for optical scanning being formed by a plastic material for optics; said scanning optical system being constructed such that a shift dλ/dT in wavelength of the light beam emitted from said light source with respect to a change in environmental temperature, a coefficient α of linear expansion of said connection holding member, a focal length f 1 and a lateral magnification β 1 of said condenser lens, chromatic aberration df 1 /dλ of the condenser lens on an optical axis thereof, a focal length f 2 , a refractive index n and a coefficient α' of linear expansion of said lens for optical scanning, a change dn/dT in refractive index of said lens for optical scanning with respect to the change in environmental temperature, and a lateral magnification β 2 of the lens for optical scanning satisfy the following condition, ##EQU30##
Claim 2
Dependent Claim
245 words
A scanning optical system comprising: a light source for emitting a light beam; a condenser lens for changing the light beam from the light source to a convergent light beam; a connection holding member for supporting the light source and the condenser lens; a deflector for deflecting the convergent light beam transmitted from said condenser lens at an equiangular velocity; and a single lens for optical scanning for scanning a scanned face at an approximately equal speed while further converging the convergent light beam deflected by the deflector and forming an image in the shape of a spot on the scanned face, said lens for optical scanning being formed by a plastic material for optics; said scanning optical system being constructed such that a shift dλ/dT in wavelength of the light beam emitted from said light source with respect to a change in environmental temperature, a coefficient α of linear expansion of said connection holding member, a focal length f 1 and a lateral magnification β 1 of said condenser lens, chromatic aberration df 1 /dλ of the condenser lens on an optical axis thereof, a focal length f 2 , a refractive index n and a coefficient α' of linear expansion of said lens for optical scanning, a change dn/dT in refractive index of said lens for optical scanning with respect to the change in environmental temperature, and a lateral magnification β 2 of the lens for optical scanning satisfy the following condition, ##EQU30##
Claim 3
Dependent Claim
94 words
A scanning optical system as claimed in claim 1, wherein a material of the connection holding member and the plastic material for optics constituting the lens for optical scanning are suitably selected in accordance with respective values of the focal length f 1 of the condenser lens, the lateral magnification β 1 of the condenser lens, the focal length f 2 of the lens for optical scanning, the lateral magnification β 2 of the lens for optical scanning, and the chromatic aberration df 1 /dλ of the condenser lens on the optical axis thereof.
Claim 4
Dependent Claim
60 words
A scanning optical system as claimed in claim 1, wherein in a case where the value of said chromatic aberration df 1 /dλ is nearly equal to zero, a focal length of said condenser lens is maintained at a substantially constant value even when the change in said wavelength of said light is caused by the change in environmental temperature.
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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) | 1995-10-13 | 1996-04-13 | 1996-10-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-10-13 | 2000-04-13 | 2000-10-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-10-13 | 2004-04-13 | 2004-10-13 | $7700.00 | Window Closed / Lapsed |