Patent ID: 6062479
Filing Date: 2000-05-16
Classification: B82Y,G02B,G06K,G07F,G07G

Abstract:
A holographic laser scanning system, comprising:a support disc rotatable about an axis of rotation, and having an inner perimeter, an outer perimeter, and an available light collecting region defined between said inner perimeter and said outer perimeter;a laser light source for producing a laser beam having first and second components characterized by first and second polarization states, respectively, said first polarization state being orthogonal to said second polarization state;a plurality of holographic optical elements supported on said support disc between said inner and outer perimeters, for scanning said laser beam and producing a laser scanning pattern for scanning a code symbol,each said holographic optical element having a beam steering portion disposed adjacent said outer perimeter for scanning said laser beam, and a light collecting portion disposed between said inner and outer perimeters for collecting laser light reflected off a code symbol scanned by said laser beam,wherein said beam steering portion of each said holographic optical element has a light diffraction efficiency that is optimized for said first polarization state of said laser beam incident thereon, and said light collecting portion of each holographic optical element has a light diffraction efficiency optimized for said second polarization state of laser light reflected off said scanned code symbol;a photodetector for detecting laser light reflected off said scanned code symbol; anda polarization-selective filter disposed before said photodetector for transmitting collected laser light having said second polarization state and blocking collected laser light having said first polarization state.