Optical system for scanning and reading barcodes with manually controlled scan beam length
First Claim
1. In a bar code scanner which has a motor, a source providing an optical beam and means driven by said motor for scanning the beam across a code, a system for controlling a motor to vary a distance across the code over which the beam is scanned which comprises:
- means for driving said motor with first control signals operative to provide a marker beam that is indexed at an initial location at a point or area on the code where said marker beam is located on the code by visual observation;
manual control means for generating multi bit digital second control signals which increase said distance such that said marker beam becomes a variable scan length scanning beam which scans across the codes with a generally constant velocity to illuminate said code to provide light which is returned from said code corresponding thereto; and
means for obtaining signals corresponding to data represented by said code from said light which is returned from said code.
5 Assignments
0 Petitions
Accused Products
Abstract
A unitary hand-held bar code scanner and reader produces an elliptical beam, oriented with its major axis along the direction of the bars, utilizing optics employing far field diffraction effects to shape the beam and maintain its elliptical aspect (length to width ratio) constant over a distance in front of the scanner were bar codes may be located. The optics eliminates parallax even though the photodetector and light source (preferably a laser diode) are located offset from each other on a board on which the optics are mounted. A housing assembly has channels which mount the board therein without shock absorbing devices. A digital microcomputer controller and peripheral devices regulate the optical power output from the laser diode and prevents catastrophic failure, if the electrical current through the laser diode exceeds safe limits. Digital control of the gain of the electronic circuits which provide the signals from which bar code information can be decoded and for the operation and control of a motor for oscillating a deflector which scans the beam across the code are also provided utilizing the microcomputer. The microcomputer also controls interface circuits to provide compatibility with auxiliary equipment and host computers which generate commands and requires data inputs of various polarity and format.
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Citations
10 Claims
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1. In a bar code scanner which has a motor, a source providing an optical beam and means driven by said motor for scanning the beam across a code, a system for controlling a motor to vary a distance across the code over which the beam is scanned which comprises:
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means for driving said motor with first control signals operative to provide a marker beam that is indexed at an initial location at a point or area on the code where said marker beam is located on the code by visual observation; manual control means for generating multi bit digital second control signals which increase said distance such that said marker beam becomes a variable scan length scanning beam which scans across the codes with a generally constant velocity to illuminate said code to provide light which is returned from said code corresponding thereto; and means for obtaining signals corresponding to data represented by said code from said light which is returned from said code. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification