RTC
®
5 PC Interface Board
Rev. 1.9 e
7 Basic Functions for Scan Head and Laser Control
145
innovators for industry
The example diagram in
illustrates how the
nonlinearity curve can be determined.
The straight line in the diagram describes ideal linear
behavior in the relationship between laser power and
the laser control signal parameter (here, the term
laser power also represents the pulse frequency =
0.5/
LaserHalfPeriod
). The curved line is an example
of a realistic relationship: here, the laser power
rises/falls more slowly than the signal parameter.
S
0
is the signal parameter value defined as the 100%
value and P
0
is the associated laser power. At point
(S
0
P
0
), the two curves intersect (this corresponds to
the data point
Percent0
= 100,
Scale0
= 1.0).
An increase (decrease) of the signal parameter to S
1
(S
2
) results in an ideal laser power P
1
(P
2
) and a real
laser power P
1r
(P
2r
). For the actually desired laser
power P
1
(P
2
), a corrective signal parameter value S
1k
(S
2k
) is needed. In this example, the following two
value pairs would then be entered as data points for
the nonlinearity curve:
Percent1
= S
1
/S
0
· 100 = P
1
/P
0
· 100
Scale1
= S
1k
/S
1
Percent2
= S
2
/S
0
· 100 = P
2
/P
0
· 100
Scale2
= S
2k
/S
2
53
S
0
S
1
S
1k
S
2
S
2k
P
0
P
1
P
1r
P
2
P
2r
Signal
Laser
power
Real
curve
Ideal
curve
0
Laser power progression – example of determining a nonlinearity
curve
