Mathieu-Gaussian beam for optical scanners
AssigneeSymbol Technologies, Inc.
InventorYajun Li
Life of this patent
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Abstract
A laser beam having a Mathieu-Gaussian intensity profile is provided, which may be used for various optical scanning applications at various scanning distances. The Mathieu-Gaussian beam exhibits a zone of illumination characterized by a central spot and side lobes centered on an axis of elongation of the zone of illumination. The zone of illumination may be used with scanners that either generate a single scan line, or another omni- or multi-directional raster pattern, to scan symbols over large variations of distance.
Claims25
An apparatus for generating a scanning beam, comprising:
- a source of an apodized Mathieu beam of coherent light;
- and
- means for scanning the beam across a target optical code.
An apparatus for generating a laser beam comprising:
- a means for generating a beam of laser light;
- a means for introducing Gaussian apodization to the beam;
- and
- a means for filtering the beam to produce confocal symmetry in the beam.
A method for creating a Mathieu-Gaussian beam comprising the steps of:
- generating a beam;
- filtering the beam;
- and
- apodizing the beam, wherein said steps are performed in any order or simultaneously to create a Mathieu-Gaussian beam.
A laser beam that is a Mathieu-Gaussian laser beam having an illumination pattern with a central spot and at least one pair of side lobes.
A laser beam for scanning a target barcode, the laser beam being an apodized Mathieu beam having a central spot and at least one pair of side lobes which define a zone of illumination which zone is elongated in a direction that is generally perpendicular to a direction in which the target barcode is scanned.
A method for designing a scanning laser beam source for an optical code reader in which a laser diode, optical system and aperture are selected for producing a Gaussian-Mathieu beam having a central spot and at least one pair of side lobes defining a zone of illumination which is relatively constant through the working range of the optical code reader, and which zone of illumination is elongated having an aspect ratio selected in accordance with the anticipated dimensions of target codes to be read by the code reader.
Dependencies are inferred from the claim text.