Datalogic VLASE IR 1109-1 42 Series, Руководство пользователя

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THERMALIZATION AND SUPPRESSION OF GIANT PULSES
USER MANUAL
111
THERMALIZATION AND SUPPRESSION OF GIANT PULSES
Thermalization is useful in order to obtain a good marking quality.
To obtain uniform markings and work processes it is important to keep the Nd:YVO4
crystal constantly pumped. This operation is called thermalization and it is implemented
by supplying the laser diode with a suitable level of current. In this way a certain
amount of pumping radiation at 808 nm excites the crystal, but with the Q-switch
closed, no laser radiation is emitted by the system.
With the Vlase™ source, this procedure can be implemented using Software Thermal-
ization.
Software thermalization
Software thermalization is implemented automatically by the Lighter marking software
and consists in defining, within the marking project, a certain thermalization level at
which the crystal is maintained during the non-emission intervals. It is generally recom-
mended to keep the level of thermalization similar to the power level used for the mark-
ing or slightly lower.
10V
5V
5V
LEVEL
EMISSION
Q-SW; MOD
DIODE CURRENT
33A
Q-SW Close
Thermalization
level
30A
150 μ s FPK time = 450 μ s
Marking time Thermalization
Marking time FPK
t
t
t
t
Figure 1: Temporal diagram of Software Thermalization
As you can see in the graph shown in the Figure, during the marking phase the Q-Switch
Modulation signal determines the frequency with which the laser pulses are generated,
the effect of the LEVEL signal is a corresponding change in the laser diode current.
Please note that, in order for this to occur, the EMISSION signal has to be active.
NOTE
During the thermalization phase, the EMISSION signal stays active, while the LEVEL sig-
nal goes into a pre-set thermalization level (i.e. 90%) and the Q SW MOD signal stays
fixed at 0 V.
Please also note that the current supplied to the laser diode is intentionally
forced to have rising and falling times in the range of 150
μ s. This protec-
tion from rapid commutations (generated by faster changes of LEVEL or
EMISSION signal fronts) is intended to reduce the risk of damage risk and
extend lifetime of the diode itself.