Siemens Optoelectronics Semiconductors. Data Book 1973/74

Munchen: Bereich Bauelemente, 1974. — 183 p.Optoelectronic components are used in modern electronics to an ever increasing degree. The main fields of application are light barriers for production control and protective devices, light control and regulating devices, e. g. twilight switches, fire detectors and devices for optical heat supervision, scanning of punched cards and perforated tapes, positioning of machine tools (for measuring length, angle and position), checking of optical equipment and ignition processes, signal transmission in case of an electrical separation of input and output, and conversion of light into electrical energy. Depending upon the application, photo-voltaic cells, solar elements, photo transistors or photodiodes are used. Photodiodes are to be preferred in cases where amplifiers with high input impedances are used. Photo transistors are primarily employed in conjunction with transistor circuits or to drive integrated circuits, whereas photo-voltaic cells are used to scan large surfaces when a strictly linear relationship between light and useful signal and optimum reliability are required. Apart from photo-electric receivers, light emitters on a semiconductor basis are used, namely light emitting diodes. Difference is here made between light emitter- on the basis of GaAs (gallium arsenide) operating in conjunction with the photo receivers mentioned above and being tuned to them with regard to spectrum and emitters on the basis of GaAsP (gallium arsenide phosphide) or GaP (gallium phosphide) radiating visible light and serving mainly as signal indicators. Components comprising both emitter and detector are termed optically coupled isolators or optoelectronic couplers. They serve to transmit electrical signals in case of an electrical separation. Furthermore, the elimination of signal feedback to the input may be an inherent advantage. The following will give further information as to technology, special characteristics and possibilities of application in the various fields. A final chapter is devoted to measuring techniques for optoelectronic components and to the most important tables and performance charts.