Patent ID: 8004553
Filing Date: 2011-08-23
Classification: G02B

Abstract:
1. An optical scanning device for scanning a member with light, comprising: a light source configured to emit a light beam; a light deflector configured to deflect the light beam; and a focusing optical system configured to guide the deflected light beam to a predetermined position of the member and including a plastic optical element, wherein the plastic optical element is molded using a die and guides the light beam to the predetermined position of the member, and wherein the plastic optical element includes: at least two transfer surfaces, which are formed by contacting with transfer surfaces of the die and which include: a light entrance surface from which the light beam enters; and a light exit surface from which the light beam exits; a third surface including a non-transfer surface formed without contacting a transfer surface of the die using compressed air; and four ribs, each formed on one of the transfer surfaces and each extending away from a center of the plastic optical element in a direction parallel to an optical axis of the plastic optical element, two of the ribs extending in one direction, and another two of the ribs extending in a direction opposite said one direction, the ribs preventing the compressed air from forming air bubbles in the light entrance surface and the light exit surface, wherein the deflected light beam passes through the plastic optical element in such a manner that an optical axis center of the deflected light beam extends in a direction parallel to a shorter side of the plastic optical element while being shifted from a dimensional center of the plastic optical element toward the third surface thereof.