Apparatus for reading optical codes

A reader for optically encoded information such as a credit card having an embossed data track includes an array of radiant energy transmitting elements and a single detector element formed on a planar chip. The chip is seated in a recessed area formed in a unitary lens assembly which includes a first integral lens array for focusing energy from each of the transmitting elements at particular points on the credit card, and a second integral lens array for focusing energy reflected from each of the points on the card onto the detector. Circuitry is provided to sequentially energize the transmitting elements, so that the focusing points, which preferably form a line transverse to the data track, are scanned. Signals from the detector element are processed by establishing a continuously variable threshold level derived as a function of the peak amount of reflected energy and by comparing the detector element output with the thresold value at several time intervals within the scanning period. The entire data track is read by repeating the scanning cycle as the credit card or other record medium is moved relative to the lens assembly.