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Bar code scanner system and scanner circuitry therefor

  • US 4,970,379 A
  • Filed: 10/12/1988
  • Issued: 11/13/1990
  • Est. Priority Date: 04/30/1987
  • Status: Expired due to Fees
First Claim
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1. In an optical scanner system,scanner means having controllable light source means for illuminating a surface containing optical information to be scanned during a scanning operation, and controllable for emitting light of adjustable intensity,optical sensor means for supplying an information signal varying in accordance with input optical information as it is scanned during a scanning operation, anda scanner circuit comprising:

  • information signal translating means coupled with said optical sensor means and supplying an output signal as a function of the intensity of the input optical information, andcontrol loop means coupled with said information signal translating means and controlling said light source means such that the light output from the light source means is reduced with increased average illumination of the optical sensor means, but said control loop means having a response time such that the information content of the optical information being scanned is reliably transmitted,said information signal translating means comprising variable gain signal amplifier means, and further control loop means coupled with said optical sensor means and responsive to intensities of the input optical information exceeding an effective operating range of the first mentioned control loop means for progressively reducing the gain of the signal amplifier means.

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