The OPB608B series Reflective Switches which consist of an infrared emitting diode and a NPN silicon phototransistor mounted "side-by-side" on a parallel axis in a black opaque plastic housing. Both the emitting diode and a phototransistor that are encapsulated in a visible filtering epoxy to further reduce ambient light noise. The phototransistor responds to radiation from the emitter only when a reflective object passes within its field of view. The phototransistor has enhanced low current roll-off to improve the contrast ratio and immunity to background irradiance.
