Title:
POST OBJECTIVE TYPE SCANNING OPTICAL SYSTEM AND IMAGE FORMING DEVICE USING THIS SYSTEM
Document Type and Number:
Japanese Patent JPH03211520
Kind Code:
A
Abstract:
PURPOSE:To reduce the cost and size of the above device and to provide a higher resolution by disposing an optical deflector, the reflecting surface of which is a cylindrical or spherical surface, and a correcting lens having such refracting power in a sub-scanning direction which changes in the central part and peripheral part of a main scanning direction and such exit surface which negates the refracting power in the main scanning direction on the incident surface. CONSTITUTION:The reflecting surface of the optical deflector 4 is formed as the cylindrical or spherical surface, by which the curvature of field in the main scanning direction is corrected. The refracting power in the sub-scanning direction of the correcting lens 5 disposed between the optical deflector 4 and the scanning surface is changed from the center in the main scanning direction toward the periphery, by which the curvature of field in the sub- scanning direction is corrected. The exit surface of the correcting lens 5 is formed to such cylindrical surface which has no refracting power in the main scanning direction over the entire part of the lens. The exertion of an adverse influence on the imaging in the main scanning direction by the correcting lens 5 is averted in this way. Further, the incident surface of the correcting lens is formed as a rotationally symmetrical surface 10 rotated around a rotationally symmetrical axis 8 parallel with the main scanning direction, by which the working is facilitated and the cost is reduced.
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Inventors:
YOSHIKAWA TOMONOBU
YAMAMOTO YOSHIHARU
YAMAMOTO YOSHIHARU
Application Number:
JP741890A
Publication Date:
September 17, 1991
Filing Date:
January 17, 1990
Export Citation:
Assignee:
MATSUSHITA ELECTRIC IND CO LTD
International Classes:
G02B26/12; G02B5/09; (IPC1-7): G02B26/10
Domestic Patent References:
| JPS61156020A | 1986-07-15 | |||
| JPH01177512A | 1989-07-13 |
Attorney, Agent or Firm:
Tomoyuki Takimoto (1 person outside)
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