Thin-film-silicon position sensors made using laser scribing

Position detectors are useful for alignment and orientation sensing. Charge-coupled devices (CCDs) are used in small-area systems. Four-quadrant diodes are a low-cost, limited-accuracy alternative. In cases where either large area or reliability under harsh conditions are required, thin-film-silicon sensors may become the only reasonable choice. The paper proposes a simple structure for making such devices, describes the first experiments and discusses the key issues faced, with emphasis on laser scribing.