METHOD FOR MISMATCH SIGNALS GENERATION FOR AUTOFOCUS SYSTEMS AND FOR SYSTEMS WHICH TRACE TRACK OF REMOVABLE OPTICAL INFORMATION CARRIER Russian patent published in 1995 - IPC

FIELD: systems for recording and reading information. SUBSTANCE: mismatch signal is generated by means of subtraction of sum of photo currents in one part of three-plate photodetector from sum of photo currents in its another part. The latter part is four photodetector side plates elements which are grouped in diagonal and oriented in same direction. Former part is four other photodetector side plates elements. Mismatch signal for track tracing system is generated by subtraction of sum of photo currents in four elements of one side plate of three-plate photodetector from sum of photo currents in four elements of its another side plate. EFFECT: increased precision and validity of tracing. 2 dwg