To improve a safety detection system for a sliding door.

The safety system for detecting an obstruction approaching doors in closing operation includes transmitter stack 40 and detector stack 42. Each transmission stack 40 includes a plurality of transmitter three-dimensional lenses. Each detector stack 42 includes a plurality of detector three-dimensional lenses. The three-dimensional lenses are offset from the corresponding optical devices to angle an outgoing or incoming signal. The present invention results in more compact packaging for the safety system and in reduced cost of the assembly therefor.