A sensor system for detecting concealed blood vessels including a handpiece having a passage for transmitting a laser beam and a detector housing at the distal end of the handpiece, the housing including a common electrode, a plurality of segmented electrodes spaced from the common electrode and between...http://www.google.co.uk/patents/US5897550?utm_source=gb-gplus-sharePatent US5897550 - Sensor system for detecting concealed blood vessels
