Punched card locating appts. - includes array of photodiodes supplying secondary light sources via optical fibres to produce light beams across path of card

摘要

The digital positioning device includes a number of light emitting sources which may be light emitting diodes. A source supplies these light with an excitation signal having a binary level of 0 or 1. Each light source is at one end of a bundle of p opical fibres, the second ends of the fibres being spaced apart. The ends of the fibres are arranged so that in order along the array of secondary light sources are the first fibres from each source in turn, then the second fibre from each source in turn. The light sources are arranged opposite phototransistors. There are p groups of n primary light receivers connected to p secondary receivers comprising phototransistors. The array is used to locate the position of a punched card in a punched card reader.