Design of Optical Proximity Switch

Design of Optical Proximity SwitchAn optical proximity switch is an electronic device which reacts to the changes of a received light flux. Optical proximity switches determine presence or absence of an object in space. Such switches consist of two stand-alone units - a source of optical radiation and a radiation receiver. A source of optical radiation, i.e. radiator, and a receiver may be designed either in a common or individual frames. The radiator consists of:a generator which produces a sequence of electric pulses onto the radiator;an emitter based on the LED which generates the optical band emission;an indicator which shows presence of supply voltage on the transmitter;an optical system which forms a radiation pattern and, if necessary, radiation polarization.The compound ensures a desired degree of protection against penetration of solids and water. The frame ensures an easy installation of the switch and protects it from mechanical strains.The receiver consists of:an optical system which forms a radiation pattern and, if necessary, performs a polarized selection.a photodetector which receives optical radiation and converts it into an electric signal.an amplifier for magnifying the input signal to a necessary value.a threshold component which ensures a necessary steepness of the output wave front and a required hysteresis value.an electronic switch for switching the output current of the device. It also determines a load connection diagram and is protected against overload and short-circuit failure.an LED colour indicator which shows state of the switch, and determines a functional backup of the selected object. It controls the operational integrity and efficiency of adjustments.A sensitivity controller adjusts the switch to a real contrast of the object in the background of surrounding objects. Modulation and spatial discrimination of light emission help to increase the efficiency of object detection. This eliminates influence of foreign exposure and interferences of other optical switches.

Category:

Science & Technology

Tags:

• light source
• receiver
• sensor