Coaligned bar codes and validation means
First Claim
1. A bar code scanner for reading coaligned bar codes comprising:
- electro-optical means for receiving and focusing light from a bar code onto a photo sensor array to produce signals corresponding to the bar code pattern;
a plurality of individually controlled light emitters each producing substantially the same wavelength of light and each being optically modulated to illuminate the bar code in a field of view of the electro-optical means;
first and second light emitters located such that an angle formed by lines from each light emitter to a common point on the bar code in the center of the field of view of the electro-optical means is at least 20 degrees;
control means having a plurality of control algorithms for controlling each of the light emitters, means for evaluating signals produced by the electro-optical means and producing evaluation data and evaluation output for an operator;
a first control algorithm means for turning on only the first light emitter, evaluating signals produced by the electro-optical means, and producing first evaluation data;
a second control algorithm means for turning on only the second light emitter, evaluating signals produced by the electro-optical means, and producing second evaluation data;
a third control algorithm means for comparing the first and second evaluation data and setting a state of authenticity to logical “
false”
if either of first and second evaluation data are invalid or if the first and second evaluation data are the same; and
a fourth control algorithm means for utilizing at least the state of authenticity to produced an evaluation output for an operator.
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Abstract
A security mark having multiple optically orthogonal coaligned bar codes is produced using a reflection hologram visible substantially at only a first wavelength that is layered over a wavelength sensitive filter, which blocks light transmission at the first wavelength but transmits light at a second wavelength, and having beneath it an additional bar code visible through the hologram and the wavelength sensitive filter at the second wavelength. A validation means reads multiple holographic bar codes with light at the first wavelength by illuminating the hologram separately from multiple directions, and further reads the bar code beneath the wavelength sensitive filter by illuminating the mark with light of the second wavelength. By suitable choice of multi-directional and multi-wavelength illumination, multiple coaligned bar codes may be read in the same physical location with no mutual interference.
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Citations
6 Claims
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1. A bar code scanner for reading coaligned bar codes comprising:
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electro-optical means for receiving and focusing light from a bar code onto a photo sensor array to produce signals corresponding to the bar code pattern; a plurality of individually controlled light emitters each producing substantially the same wavelength of light and each being optically modulated to illuminate the bar code in a field of view of the electro-optical means; first and second light emitters located such that an angle formed by lines from each light emitter to a common point on the bar code in the center of the field of view of the electro-optical means is at least 20 degrees; control means having a plurality of control algorithms for controlling each of the light emitters, means for evaluating signals produced by the electro-optical means and producing evaluation data and evaluation output for an operator; a first control algorithm means for turning on only the first light emitter, evaluating signals produced by the electro-optical means, and producing first evaluation data; a second control algorithm means for turning on only the second light emitter, evaluating signals produced by the electro-optical means, and producing second evaluation data; a third control algorithm means for comparing the first and second evaluation data and setting a state of authenticity to logical “
false”
if either of first and second evaluation data are invalid or if the first and second evaluation data are the same; anda fourth control algorithm means for utilizing at least the state of authenticity to produced an evaluation output for an operator. - View Dependent Claims (2, 3)
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4. A bar code scanner for reading coaligned bar codes comprising:
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electro-optical means for receiving and focusing light from a bar code onto a photo sensor array to produce signals corresponding to the bar code pattern; a plurality of individually controlled light emitters each producing substantially one of a first or different second wavelength of light, and each being optically modulated to illuminate the bar code in the field of view of the electro-optical means; first and second light emitters for producing the first wavelength of light located so that a first angle formed by lines from each light emitter to a common point on the bar code in the center of the field of view of the electro-optical means is at least 20 degrees; third and fourth light emitters for producing the second wavelength of light substantially colocated respectively with the first and second light emitters so that a second angle formed by lines from each light emitter to a common point on the bar code in the center of the field of view of the electro-optical means is substantially the same as the first angle control means having a plurality of control algorithms for controlling each of the light emitters, evaluating the signals produced by the electro-optical means, producing evaluation data, and producing an evaluation output for an operator; a first control algorithm for turning on only the first light emitter, evaluating the signals produced by the electro-optical means, and producing first evaluation data; a second control algorithm for turning on only the second light emitter, evaluating the signals produced by the electro-optical means, and producing second evaluation data; a third control algorithm for turning on only the third light emitter, evaluating the signals produced by the electro-optical means, and producing third evaluation data; a fourth control algorithm for turning on only the fourth light emitter, evaluating the signals produced by the electro-optical means, and producing fourth evaluation data; a fifth control algorithm for comparing the first and second evaluation data and setting a state of authenticity to logical “
false”
if either of first and second evaluation data are invalid or if first and second evaluation data are the same; anda sixth control algorithm for comparing the third and fourth evaluation data and setting the state of authenticity to logical “
false”
if either of third and fourth evaluation data are invalid, or if the third and fourth evaluation data are not identical; anda seventh control algorithm for utilizing at least the state of authenticity to produce an evaluation output for an operator. - View Dependent Claims (5, 6)
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Specification