Beam with extended confinement for scanning purposes
AssigneeSymbol Technologies, Inc.
InventorsEmanuel Marom, Naim Konforti, David Mendlovic
Life of this patent
Estimating the term…
Abstract
Scanner optics, usable for example in a bar code reader, generate a multitude of Gaussian beams derived from a common light source to produce a beam with extended working range. In the preferred embodiment, a 360 degree fan of Gaussian beams is generated by passing a laser beam through at least one diffractive element, e.g., computer generated holographic (CGH) plate, computed to perform the transformation of the illuminating beam into the desired output beam. The beam thus produced, having a small diameter over a large longitudinal distance, is useful for long range scanning.
Claims37
A device for generating a narrow beam with limited spread along the beam's propagation direction, said device comprising:
- (a) a radiation source;
- (b) means for producing, from said radiation source, an effect of a plurality of Gaussian beams surrounding a common axis and intersecting in a common spatial region to define a synthesized long working range beam;
- and
- (c) means for directing said synthesized long working range beam toward at least one preferred direction.
A scanner for scanning optically encoded indicia of varying light reflectivity, said scanner comprising:
- (a) a light source for generating a collimated Gaussian beam of light;
- (b) means for producing from said Gaussian beam of light, an effect of a plurality of Gaussian beams surrounding a common axis and intersecting in a common spatial region to produce a synthesized long working range beam;
- (c) means for directing said synthesized beam toward indicia to be scanned and for causing the synthesized beam to move along a scan line;
- and
- (d) a light detector positioned to receive light reflected from said indicia.
A scanner for scanning optically encoded indicia of varying light reflectivity, said scanner comprising:
- (a) means for generating an effect of a plurality of Gaussian light beams angularly displaced about a common axis by a given angle and intersecting each other in a common spatial region to form a synthesized beam of light;
- (b) means for directing said synthesized beam of light toward indicia to be scanned and for causing the synthesized beam to move along a scan line;
- and
- (c) a light detector positioned to receive light reflected from said indicia.
A method of scanning a symbol, comprising the steps of:
- generating an effect of a plurality of Gaussian light beams of prescribed relative amplitudes and phases, surrounding a common axis and intersecting each other in a common spatial region to form a synthesized beam of light;
- directing said synthesized beam of light toward a symbol to be scanned and causing the synthesized beam to move along a scan line;
- and
- detecting light reflected from said symbol.
A bar code reader comprising:
- a housing;
- symbol detection means, contained in said housing, for generating a laser beam directed along a path toward a bar code symbol to be read and for receiving light reflected from the bar code symbol to produce electrical signals corresponding to the intensity of the reflected light;
- and
- means, positioned in said path, for generating from said laser beam an effect of a plurality of Gaussian light beams angularly displaced about a common axis by a given angle and intersecting each other in a common spatial region to form a synthesized beam of light which impacts on and is reflected by said bar code symbol.
Dependencies are inferred from the claim text.