Patent ID: 7370798

Claim:
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.