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Tristimulus colorimeter

  • US 4,125,329 A
  • Filed: 09/07/1976
  • Issued: 11/14/1978
  • Est. Priority Date: 09/07/1976
  • Status: Expired due to Term
First Claim
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1. A comparison type optical measuring apparatus, comprising:

  • photosensitive means for producing an electrical output representative of light received thereby,optical means for sequentially directing unknown and reference light beams to said photosensitive means thereby to cause said photosensitive means to produce, respectively, unknown and reference electrical signals,integrator means for integrating in one polarity direction one of said unknown and reference electrical signals for a predetermined duration to produce an integrated signal level and then in the opposite polarity direction the other of said unknown and reference electrical signals, and common circuit means for directing said unknown and reference electrical signals to said integrator meansoutput means for producing an electrical output signal indicative of the time required for said integrator means to integrate said other of said unknown and reference electrical signals from such integrated signal level to a predetermined signal level, whereby said electrical output signal is representative of a comparison of said unknown and reference light beams.

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