Title:
F-THETA LENS
Document Type and Number:
Japanese Patent JPH02162316
Kind Code:
A
Abstract:
PURPOSE:To obtain an f.theta lens with excellent aberration characteristics by arranging four positive, negative, positive, and positive lenses with specific radii of curvature and specific refracting indexes at specific positions in order from a beam deflector. CONSTITUTION:A 1st lens counted from the beam deflector is a positive lens, a 2nd lens a negative lens, and 3rd and 4th lenses are positive lenses. Then the distance from a pupil to the 1st lens is set to 42.3mm and various elements of the 1st, 2nd, 3rd, and 4th lenses are specified. Namely, r1 is -101.17mm, r2 -82.754mm, d1 8.8mm, n1 1.7379, d2 2.9mm, r3 84.32mm, r4 -706.0mm, d3 6.0mm, n2 1.59302, d4 19.55mm, r5 -519.1mm, r6 -149.0mm, d5 15.0mm, n3 1.7379, d6 0.5mm, r7 3465.0mm, r8 -439.5mm, d7 10.0mm, n4 1.7379, and d8 564.36mm.
Inventors:
TASHIRO KATSU
YAMAGISHI YASUSHIGE
SUGIZAKI IWAO
KINOSHITA SABURO
FUNASHIMA TOSHIO
YAMAGISHI YASUSHIGE
SUGIZAKI IWAO
KINOSHITA SABURO
FUNASHIMA TOSHIO
Application Number:
JP31623488A
Publication Date:
June 21, 1990
Filing Date:
December 16, 1988
Export Citation:
Assignee:
COPAL ELECTRONICS
International Classes:
G02B26/10; G02B3/06; G02B13/00; (IPC1-7): G02B3/06; G02B13/00; G02B26/10