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An optical device for detecting bar codes (markings or patterns which symbolize data such as the name and vendor of a product) are detected by an optical device which serves as a bar code scanner. A laser diode and associated optics provides an invisible beam. A visible marker beam coincident with t

An optical device for detecting bar codes (markings or patterns which symbolize data such as the name and vendor of a product) are detected by an optical device which serves as a bar code scanner. A laser diode and associated optics provides an invisible beam. A visible marker beam coincident with the laser beam is generated by a lamp and associated optics and directed coaxial with the laser beam so as to enable the laser beam to be scanned across the bar code by moving a housing in which the laser and the lamp and their associated optics are disposed. Also contained in the housing is a photodetector on which scattered light from the code is incident after passing through a collection lens located at an outlet port for the beams. An aperture is positioned between the collection lens and the detector. The location and size of the aperture and the focal length of the lens are related such that the illumination by the reflected light of the detector is substantially constant and the output signal from the detector which represents the bar code is also constant amplitude over a wide depth of focus in front of the beam port. Unwanted reflections (gloss over the bar code) are rejected by selecting the polarization of the reflections opposite to the polarization of the laser beam, as by the use of a polarizing beam splitter. A spectral beam splitter is used near the detector to select the scattered laser light for the photodetector which generates electrical signals corresponding to the bar code.

대표청구항 ▼

An optical device for detecting coded symbols having relatively more and less reflective regions which comprises means for illuminating said code symbols with a first light beam which is substantially invisible, means for simultaneously illuminating said symbols with a marker beam of light which is

An optical device for detecting coded symbols having relatively more and less reflective regions which comprises means for illuminating said code symbols with a first light beam which is substantially invisible, means for simultaneously illuminating said symbols with a marker beam of light which is visible and which is coincident with said first beam to enable said first beam to be located with respect to said symbols, and means responsive to reflections of said first beam from said symbols for translating said symbols into corresponding electrical signals.