Light scanning system

• US 5,130,840 A
• Filed: 11/12/1991
• Issued: 07/14/1992
• Est. Priority Date: 08/26/1987
• Status: Expired due to Term

• Current Assignee: Asahi Kogaku Kogyo Kabushiki Kaisha
• Original Assignee: Asahi Kogaku Kogyo Kabushiki Kaisha
• Inventors: Iima, Mitsunori, Morimoto, Akira
• Primary Examiner(s): Arnold, Bruce Y.
• Assistant Examiner(s): Phan, James
• Application Number:
  US07/791,017
• Time in Patent Office: 245 Days
• Field of Search: 359/205, 359/207, 359/196, 359/209-210, 359/212, 359/216, 359/220, 359/221, 359/223, 359/226, 359/433, 359/710, 359/711
• US Class Current: 359/220.1
• CPC Class Codes: G02B 26/12 using multifaceted mirrors
• CPC Class Codes: G02B 27/0031 for scanning purposes
• CPC Class Codes: G02B 5/09 Multifaceted or polygonal mirrors , e.g. polygonal scanning mirrors; Fresnel mirrors

Abstract

A light scanning system has a light source, a deflecting device, an anamorphic scanning lens having different refracting powers in a principal scanning plane and in a secondary scanning plane perpendicular to the principal scanning plane, and another anamorphic convex lens, such as a cylindrical lens, having a larger refracting power in the secondary scanning plane than in the principal scanning plane. The anamorphic convex lens is rotatable for adjustment about an axis of rotation that is substantially parallel with the optical axis of the optical system. When a tapered polygon mirror is used as the deflecting device, the anamorphic convex lens is mounted in a tilted manner such that two principal meridians projected via the reflecting surface of the deflecting device substantially coincide with respective scanning planes.

Claims

1. A light scanning system, comprising:

a light source;

a tapered polygon mirror having a plurality of reflecting surfaces respectively inclined by a substantially identical angle with respect to the axis of rotation thereof for reflecting and deflecting a beam of light emitted from said light source;

a scanning lens for converging said deflected light beam onto a subject surface to be scanned; and

an anamorphic convex lens having a refracting power in a principal scanning plane, containing the direction of scanning of said light beam, that is smaller than in a secondary scanning plane that is perpendicular thereto, said anamorphic convex lens being mounted in a tilted manner such that two principal meridians projected via said reflecting surface substantially coincide with each scanning plane.

2. The light scanning system as claimed in claim 1, wherein said anamorphic convex lens comprises a cylindrical lens.

3. The light scanning system as claimed in claim 1, wherein said scanning lens comprises an anamorphic system having different refracting powers in said principal scanning plane and in said secondary scanning plane, said anamorphic convex lens being mounted in a tilted manner such that the principal meridians of said anamorphic convex lens projected via said reflecting surfaces substantially coincide with each principal meridian of said scanning lens.