Title:
TELECENTRIC FTHETA LENS AND OPTICAL SCANNING DEVICE
Document Type and Number:
Japanese Patent JP3142380
Kind Code:
B2
Abstract:
PURPOSE: To provide the telecentric fθ lens which is bright and has high performance and the new optical scanning device which excellently correct the surface tilt of an optical deflector by using the fθ lens.
CONSTITUTION: A 1st group is a positive meniscus lens 1, a 2nd group a combined lens of a meniscus lens 3 and a negative lens 2, a 3rd group a positive meniscus lens 4, a 4th group a positive meniscus lens, and a 5th group a positive lens 6; and conditions of (1) -0.9<R2/f1<-0.1, (2) -0.7<f2/f1<-0.1, (3) -0.8<f2/f<-0.3, (4) 0.5<R8/R10<1.0, and (5) 0.4<f3,4/f<1.8 are satisfied, where f is the focal length of the whole system, f1 the focal length of the 1st group, f2 the composite focal length of the 2nd group, f3,4 a the composite focal length of the 3rd and 4th groups, and Ri(i=1-12) a radius of curvature of an (i)th lens surface.
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Inventors:
Katsuaki Ono
Application Number:
JP20235092A
Publication Date:
March 07, 2001
Filing Date:
July 29, 1992
Export Citation:
Assignee:
Ricoh Optical Co., Ltd.
International Classes:
G02B13/00; G02B26/10; (IPC1-7): G02B13/00; G02B26/10
Domestic Patent References:
| JP497211A | ||||
| JP60123815A | ||||
| JP293511A |
Attorney, Agent or Firm:
Toru Kabayama (1 person outside)