摘要 |
A laser diode (22) emits laser light which is collimated into parallel rays with a collimating lens (24). The collimated beams travel about 5 to 50 cm before being reflected back to an adjustable mirror (28), to a fixed mirror (30), and then on to a photoreceiver (34). The adjustable mirror (28) is pivoted by turning an adjusting screw (40). The adjustable mirror (28) has a toothed cam (48) on its backside that mate with the threads of the adjusting screw (40). When the adjusting screw (40) is turned, it forces the cam to move with it, thus changing the angle of the adjustable mirror (28). A ball lens (32) focuses the reflected light onto the photoreceiver (34). The photoreceiver (34) and laser diode (22) are synchronized so that the receiver (34) can only receive light during appropriate windows of time corresponding to when the laser light was emitted. The photoreceiver (34) has the ability to tell when it is and when it is not receiving laser light and has the ability to initiate action based upon that information.
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