Patent US2407515A successfully refreshed from Google Patents.
Patent US3284661A successfully refreshed from Google Patents.
Patent US3460574A successfully refreshed from Google Patents.
Patent US5155616A successfully refreshed from Google Patents.
US5155616A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Scanning optical system
Assignee: Ricoh Co Ltd
•
Filing: 1991-10-29
•
Granted: 1992-10-13
•
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 02:04
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.
References Cited (Backward Citations)
JPS587109A
Cited
JPS5915205A
Cited
US4720168A
Cited
JPS62183411A
Cited
US4815059A
Cited
US4855987A
Cited
US4906061A
Cited
US4934772A
Cited
US4962982A
Cited
US5005928A
Cited
US4955682A
Cited
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 |