Patent ID: 6540146
Filing Date: 2003-04-01
Classification: G02B,G06K

Abstract:
An improvement of scanning projection light source for barcode device, comprising:a laser diode for emitting a laser light spot; a converging lens located in font of the laser diode for receiving and converting the laser light spot to a parallel light beam; a first photo mask located in front of the converging lens having a round aperture for transforming the parallel light beam to become a projecting round light spot; a second photo mask located in front of the first photo mask having a second aperture which has two light blocking tabs located at two lateral sides thereof for partly blocking the projecting round light spot to become an output light spot which has arched tangent sides; wherein each arched tangent side approximates to a straight line at a selected distance close to the second photo mask for generating a higher resolution, and becomes an arched tangent side at a selected distance remote from the second photo mask for generating a lower resolution.