Optical beam scanner

Abstract

Abstract PURPOSE:To correct the wobbling and surface inclination of a deflector and to reduce the curvature of field so as to make highly accurate scanning, by converging beams in the auxiliary scanning direction by means of a concave cylindrical half mirror provided between a scanning lens and scanning surface. CONSTITUTION:Light from a laser light source 1 is made incident on a concave cylindrical half mirror 10 provided under a condition where it is elongated in the main scanning direction and converged onto a scanning surface 9 after the light is reflected and deflected by means of a rotary polygon mirror 5 and made incident on a scanning lens 6. The length of the optical path from the lens 6 to the scanning surface 9 is set equally to the focal length of the lens 6 and the light is converged on the surface 9 irrespectively of the wobbling and surface inclination of the polygon mirror 5, and thus, the light makes auxiliary scanning in the direction shown by the arrow C and main scanning in the direction shown by the arrow A. On the other hand, a beam 2b transmitted through the half mirror 10 is condensed on a light condensing bar 12 after passing through a grid 11 and the scanning location is detected by a detector 13. Since the mirror 10 is used, the wobbling and surface inclination of the deflector can be corrected and the curvature of field is reduced, resulting in highly accurate scanning.

Inventors

• 👤 Masaru Noguchi
• 👤 勝 野口

Bibliographic Details