Scanning optical system
Filing Information
- Patent Number: US5715079
- Application Number: US8547502
- Filing date: 10/24/1995
- Issue date: 02/03/1998
- Predicted expiration date: 12/13/2014
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analyzing 100 million+ documents to uncover your network...- U.S. Classifications: 359/205 · 359/206 ·
- International Classifications: G02B 2608 ·
- International Classifications: 359196-219;220;662;711;717;793;795 ·
- Related U.S. Application Data:
This is a division of prior application Ser. No. 08/354,604, filed on Dec. 13, 1994, for a SCANNING OPTICAL SYSTEM. - Foreign Priority: JP5316757 - 12/16/1993 · JP6195257 - 08/19/1994 ·
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Abstract
A scanning optical system has a deflector and a scanning lens. A convergent beam is deflected at a uniform angular velocity by the deflector. The scanning lens forms the scanned beam into an image on a scanned surface to scan the surface substantially at a uniform velocity. The scanning lens includes from the side of the deflector a negative lens element and at least one more lens element. The convergent beam is incident on a surface of the deflector which faces the deflector. The scanning lens fulfills predetermined conditions.References Cited
U.S. Patent Documents
| Document Number | Assignees | Inventors | Issue/Pub Date |
|---|---|---|---|
| US4443055 | Canon Kabushiki Kaisha | Matsuoka et al. | Apr 1984 |
| US5111219 | Canon Kabushiki Kaisha | Makino | May 1992 |
| US5128795 | Ricoh Company, Ltd. | Endou et al. | Jul 1992 |
| US5179277 | Ricoh Company, Ltd. | Tomita | Jan 1993 |
| US5247385 | Ricoh Company, Ltd. | Takanashi | Sep 1993 |
| US5499107 | Minolta Co., Ltd. | Kuroda | Mar 1996 |
Foreign Patent Documents
| Document Number | Assignees | Inventors | Issue/Pub Date |
|---|---|---|---|
| JP242414 | Feb 1990 | ||
| JP4110817 | Apr 1992 | ||
| JP4153616 | May 1992 |
Referenced By
| Document Number | Assignee | Inventors | Issue/Pub Date |
|---|---|---|---|
| US6100912 | Kabushiki Kaisha Toshiba | Takashi Shiraishi et al. | Aug 2000 |
| US5808773 | Minolta Co., Ltd. | Satoru Ono | Sep 1998 |
| US7557974 | Canon Kabushiki Kaisha | Yuichi Tomioka et al. | Jul 2009 |
| US7295722 | Seiko Epson Corporation | Masatoshi Yonekubo | Nov 2007 |
| US7116347 | Ricoh Company, Ltd. | Atsushi Kawamura | Oct 2006 |
| US6154303 | Samsung Electro-Mechanics Co., Ltd. | Cheon Seog Rim et al. | Nov 2000 |
| US6556332 | Canon Kabushiki Kaisha | Keiichiro Ishihara | Apr 2003 |
| US6690497 | Canon Kabushiki Kaisha | Keiichiro Ishihara | Feb 2004 |
| US6549227 | Kabushiki Kaisha Toshiba | Takashi Shiraishi et al. | Apr 2003 |
| US7050082 | Ricoh Company, Ltd. | Mitsuo Suzuki et al. | May 2006 |
| US6075637 | Minolta Co., Ltd. | Yoshihiro Inagaki | Jun 2000 |
| US6134040 | Samsung Electro-Mechanics Co. | Cheon Seoq Rim et al. | Oct 2000 |
| US6657652 | Kabushiki Kaisha Toshiba | Takashi Shiraishi et al. | Dec 2003 |
| US7450284 | Canon Kabushiki Kaisha | Yuichi Tomioka et al. | Nov 2008 |
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Independent Claims | See all claims (20)
- 1. A scanning optical system comprising:a deflector;a scanning lens on which a convergent beam deflected by the deflector at a uniform angular velocity is incident, said scanning lens forming the convergent beam into an image on a scanned surface to scan the scanned surface substantially at a uniform velocity,wherein said scanning lens includes from a deflector side a first lens element of a negative refractive power and a second lens element of a positive refractive power, and wherein one surface of the second lens element is a toric surface where its refractive power in a main scanning direction and its refractive power in a sub scanning direction are different, and wherein said scanning lens fulfills the following condition:.vertline.1-.beta..vertline.<0.25where .beta. is a magnification of the scanning lens in the main scanning direction.
- 4. A scanning optical system comprising:a deflector;a scanning lens on which a convergent beam deflected by the deflector at a uniform angular velocity is incident, said scanning lens forming the convergent beam into an image on a scanned surface to scan the scanned surface substantially at a uniform velocity,wherein said scanning lens includes from a deflector side a first lens element of a negative refractive power and a second lens element of a positive refractive power, and wherein said scanning lens fulfills the following condition:.vertline.-.beta..vertline.< 0. 25where .beta. is a magnification of the scanning lens in a main scanning direction.
- 13. A scanning optical system comprising:a deflector;a scanning lens on which a convergent beam deflected by the deflector at a uniform angular velocity is incident, said scanning lens forming the convergent beam into an image on a scanned surface to scan the scanned surface substantially at a uniform velocity,wherein said scanning lens includes from a deflector side a first lens element of a negative refractive power and a second lens element of a positive refractive power, and wherein one surface of the second lens element is a toric surface where its refractive power in a main scanning direction and its refractive power in a sub scanning direction are different, and wherein said scanning lens fulfills the following condition: ##EQU22## wherein .beta. is a magnification of the scanning lens in the main scanning direction, f.sub.1M is a focal length of the first lens element in the main scanning direction, f.sub.1S is a focal length of the first lens element in the sub scanning direction, f.sub.2M is a focal length of the second lens element in the main scanning direction, and f.sub.2S is a focal length of the second lens element in the sub scanning direction.
- 16. A scanning optical system comprising:means for providing an optical beam;means for converging the optical beam;a deflector for scanning the converging optical beam and positioned relative to the means for converging to deflect an optical beam as a reflected convergent beam; anda scanning lens on which a convergent beam deflected by the deflector at a uniform angular velocity is incident, said scanning lens forming the convergent beam into an image on a scanned surface to scan the scanned surface substantially at a uniform velocity,wherein said scanning lens includes, from a deflector side a first lens element of a negative refractive power and a second lens element of a positive refractive power, at least one of the first and second lens elements is made from a resin material, and wherein one surface of the second lens element is a toric surface where its refractive power in a main scanning direction and its refractive power in a sub scanning direction are different, and wherein said scanning lens fulfills the following condition:.vertline.1-.beta..vertline.<0.25where .beta. is a magnification of the scanning lens in the main scanning direction.
- 18. A scanning optical system comprising:means for providing an optical beam;means for converging the optical beam;a deflector for scanning the converging optical beam and positioned relative to the means for converging to deflect an optical beam as a reflected convergent beam; anda scanning lens on which a convergent beam deflected by the deflector at a uniform angular velocity is incident, said scanning lens forming the convergent beam into an image on a scanned surface to scan the scanned surface substantially at a uniform velocity,wherein said scanning lens includes, from a deflector side a first bi-concave lens element of a negative refractive power and a second meniscus lens element of a positive refractive power, at least one of the first and second lens elements is made from a resin material, and wherein one surface of the second lens element is a toric surface where its refractive power in a main scanning direction and its refractive power in a sub scanning direction are different, and wherein said scanning lens fulfills the following condition:.vertline.1-.beta..vertline.<0.25where .beta. is a magnification of the scanning lens in the main scanning direction.
- 20.20. A scanning optical system comprising:a deflector;a scanning lens on which a convergent beam deflected by the deflector at a uniform angular velocity is incident, said scanning lens forming the convergent beam into an image on a scanned surface to scan the scanned surface substantially at a uniform velocity,wherein said scanning lens includes from a deflector side a first lens element of a negative refractive power and a second lens element of a positive refractive power, and wherein said scanning lens fulfills the following conditions:.vertline.1-.beta..vertline.<0.25where .beta. is a magnification of the scanning lens in a main scanning direction, ##EQU23## where f.sub.2M is a focal length of the second lens element in the main scanning direction and f.sub.2S is a focal length of the second lens element in a sub scanning direction.
