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(57) ABSTRACT A reflection-type photoelectric proximity detector and switch is capable of detecting the incremental and bi nary proximity of a finger through several layers of glass, cancelling out extraneous reflections and stray sources of radiation. The circuitry includes a modulated infrared emitter, an infrared detector, an optical barrier, an infrared filter, a bandpass filter, a signal rectifier, a biasing circuit to remove unwanted detected modulated signal, an amplifier, an incremental proximity output, a comparator, a detection reference, and a binary proxim ity detect output. In one embodiment a multitude of photoelectric proximity switches are installed on the inside of a store window, detect finger proximity from outside the window, and control electric appliances inside the store window. From outside the window, a user can select what is displayed inside the window.