Title:
OPTICAL SCANNER
Document Type and Number:
Japanese Patent JPH0497210
Kind Code:
A
Abstract:
PURPOSE:To reduce the production cost of an optical scanner by arranging an ftheta lens between a deflective reflection face and a face to be scanned and constituting the ftheta lens of a specific 3rd group lens. CONSTITUTION:The optical scanner is provided with a cylindrical lens 1, the deflective reflection face 2 for deflecting a linear converged beam projected from the lens 1 and the ftheta lens A arranged between the reflection face 2 and the face to be scanned. The ftheta lens is constituted of the 3rd group lens having the 1st group 3 consisting of a parallel plane plate, the 2nd group 4 having positive power and a spherical surface in which the center of curvature of a scanned face side face is arranged on the deflector side and the 3rd group 5 having positive power and a toric face in which the center of curvature of the scanned face side face is arranged on the deflector side in both the main scanning and sub-scanning directions. Since a comparatively inexpensive glass material can be used and an image point position in the sub-scanning direction can be corrected without selecting a semiconductor laser light source, the production cost of the whole optical scanner can be reduced.
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Inventors:
TAKEI SHOICHI
FURUTA HIROYUKI
FURUTA HIROYUKI
Application Number:
JP21332690A
Publication Date:
March 30, 1992
Filing Date:
August 10, 1990
Export Citation:
Assignee:
TOMIOKA KOUGAKU KK
International Classes:
G02B26/10; G02B13/00; G03G15/04; (IPC1-7): G02B13/00; G02B26/10; G03G15/04
Attorney, Agent or Firm:
Hideki Yamamoto
Next Patent: TELECENTRIC FTHETA LENS