Title:
OPTICAL SCANNER
Document Type and Number:
Japanese Patent JPH03102309
Kind Code:
A
Abstract:
PURPOSE:To obtain a scanning optical system which has small curvature of field without using any ftheta lens by combining a lens which includes a diffraction grating structure with a movable spot light source and a light source whose oscillation frequency is variable. CONSTITUTION:A semiconductor laser 101 is used as the light source whose oscillation frequency is variable, and a 1st lens 103 is provided with an actuator 104, which moves a 1st image point 105 in the optical axis direction. A 2nd lens 106 is provided with a micro-Fresnel lens 107 which has the diffraction grating structure. When a rotary polygon mirror 108 rotates in such constitution, the image point 105 is shifted in position through the actuator 104 onto a straight scanning line 111, and the oscillation frequency of the semiconductor laser 101 is varied to cancel the movement of the image point and aberrations.
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Inventors:
YOKOYAMA OSAMU
Application Number:
JP24117389A
Publication Date:
April 26, 1991
Filing Date:
September 18, 1989
Export Citation:
Assignee:
SEIKO EPSON CORP
International Classes:
G02B26/10; H04N1/04; H04N1/113; (IPC1-7): G02B26/10; H04N1/04
Attorney, Agent or Firm:
Kisaburo Suzuki (1 outside)