Opto-electronic code character reader - has light source with multiple photodetectors forming multi-linear or concentric array and light barrier for light path

摘要

The reader (1) detects perforations of applied reflective markings (9) using a spaced light source (3) and photodetector (4), with a cylindrical, spherical or hemispherical lens (5) in the light path between them. The light source (3) and photodetector (4) are spaced in the direction of relative displacement of the reader (1) and the support (6) carrying the markings (7), or alternatively a single light source (3), is surrounded concentrically by a number of photodetectors (4). Alternately a number of light sources (3) concentrically surround a single photodetector. A light barrier (2) blocks the direct light path between the light source (3) and the photodetector (4). The reader (1) may incorporate more than one light source and photodetector group which lie along a line perpendicular to the direction of relative displacement. The reader can be used for a data input using perforated cards or data tapes.