KEYENCE LS-3100/3100W Series - Manual (Page 89)

83
APPENDIX A
O
PERATING
P
RINCIPLE
Laser beam emitted by semiconductor is reflected first by the polygonal
mirror, then by the reflector mirror. Laser beam is scanned according to the
rotational angle of the polygonal mirror during this process. Then, scanned
beams pass through the collimator lens so that they run parallel to each
other. These beams are directed at the target and converged onto a
photodiode by another lens. The beams thus collected are converted into an
electric signal corresponding to the light-dark pattern produced.
The dimension of the target is determined by the width of "dark" region
measured in terms of time.
Photodiode
Receiving
lens Collimeter lens
(Fθ lens) Photodiode
(for synchronization)
Reflector
(mirror)
Target
Edge
detection
Semiconductor
laser
Polygonal mirror
Waveform
shaping
Latch Counter
Clock
pulse
Data
display
Key input
Relay output
Analog output
Control I/O BCD output*
*Option *Option
CPU
RAM
ROM
RS232C GP-IB*
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