Operating Principles
Laser 1000/1500 Service Manual
2.1.2.5
Laser Diode Drive
Figure 2-23 shows the laser diode
drive circuit. Laser diode emission is controlled by three signals
(L
DATA, DA1,
and
from the engine controller board
S SCAN
co
LD
DAI
Sos
L DATA
Engine Controller
Board
Laser Diode
SOS Mirror
SOS sensor
Figure 2-23. Laser Diode Drive Circuit
The L DATA signal is the laser ON/OFF signal. When it is LOW, the laser emits, and when it is
HIGH, laser stops emitting. L DATA is the combination of the two signals in the figure below. If
the VIDEO or the FORCED LASER DIODE ON signal is activated (LOW), the
L DATA signal will be active. The VIDEO signal is an image signal sent from the video controller
board
MAIN board). The FORCED LASER DIODE ON signal is a laser emission signal to
apply the
beam to the SOS sensor.
Forced
Diode ON
from the Video Controller
Board
MAIN Board)
Figure 2-24. /L DATA Generation Circuit
The laser diode is forcibly activated within between
0.2
seconds and 0.1 seconds after the scanner
mirror motor
turns ON. At this time, laser emission power is adjusted.
and
are the laser emission power adjust signals; they are analog signals.
is a tuning.
is a
fine tuning.
Scanner Motor On
LDATA
k
0.1
0.2
I
(CN5A-7)
I
: :
(CN5A-1O)
:
:
LDLVL
: :
: : :
(CN5A-11)
2-25. Laser Emission Power Adjustment Timing
