Light Sensors and Switches

A wide range of light sensing components and light switching options. Ambient Light Sensors can be used whenever a high resolution light sensor with a two-wire digital interface is required. Applications include street light control, security lighting, sunlight harvesting, machine vision, automotive instrumentation clusters. Ambient light sensing offers up to 30% in energy saving for portable products, by controlling the display brightness depending on the lighting environment. Transmissive IR Switches - including slotted switches, optical digital encoders and transmissive photo ICs – contain an emitter which transmits IR light and a detector in line which detects the light directly. Reflective IR Switches, or reflective optical switches, consist of a housing containing both a light source and a detector. Light from the source radiates outward, and is reflected back if an object passes in front of the switch. The reflected light is sensed by the detector. Reflective switches can be used to detect the proximity of an object and may therefore be referred to as proximity sensors. Photodiodes are solid state light detectors that, when illuminated, generate an output which is proportional to light level. A photodiode consists of a shallow diffused P-N junction with accessible connections. Phototransistors are solid state light detectors that possess internal gain (which can range from 100 to over 1500) and are consequently much more sensitive than photodiodes of comparably sized area. An optoisolator, or optocoupler, is a semiconductor device which transfers an electrical signal optically between two parts of a circuit, thereby keeping them electrically isolated.