The Hurryscan ® 10 - Principle Of Operation; Dynamic Positioning Laser Beams; Customized Optical Configuration - Scanlab hurrySCAN 10 Installation & Operation Manual

2 The hurrySCAN
2.1 Dynamic Positioning Laser
Beams
The primary tasks of an X-Y scan head are to deflect
a laser beam in the X-Y directions and to focus the
beam onto the working plane.
X
F-Theta
Objective
Y
d
i e l
Beam in
e F
a g
I m
Basis of Operation: beam deflection via two galvanometer scanners
The beam deflection task is realized with the help of
two tiltable deflection mirrors (see
beam enters the scan head through the input aper-
ture and is first deflected in the Y direction by
mirror 1 attached to galvanometer scanner 1. The
beam then goes on to be deflected in the X direction
by mirror 2 attached to galvanometer scanner 2. The
resulting deflection angles can be precisely and high-
dynamically adjusted by controlling the positions of
the galvanometer scanners.
Focusing the beam onto the working plane can be
achieved with the help of a scan lens fitted to the
scan head's beam exit hole. If an F-Theta objective is
used, the position of the focal point on the image
field will be directly proportional to the angle of inci-
dence of the beam.
Alternatively, focusing of the beam can be realized
with the help of a dynamic focusing system (for
instance, SCANLAB's varioSCAN 20) positioned in
front of the scan head's entrance aperture.
®
hurrySCAN 10, digital, 1064 nm, f = 254 mm
Rev. 2.6 e
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2 The hurrySCAN 10 – Principle of Operation
®
10 – Principle of Operation

Customized Optical Configuration

To obtain optimum optical performance for a partic-
ular laser application, the scan head's optical config-
uration must meet the requirements of the
application and the used laser system. To achieve
optimum reflectivity at the mirrors, SCANLAB there-
fore selects mirror coatings appropriate for the wave-
Galvanometer
length and power of the user's laser. The size of the
Scanner 2
mirrors or the scan head's aperture is selected in
accordance with the desired spot size and scan
speed. The spot size is also influenced by the objec-
Mirror 2
tive, which is also selected in accordance with the
Mirror 1
desired field size (or working distance A between the
laser input and the image field) as well as the wave-
length and power of the user's laser.
The user, on the other hand, has to ensure that the
Galvanometer
Scanner 1
parameters of the entering laser beam (wavelength,
power density and diameter) match the specifica-
2
tions of the scan head.
First the coatings of the deflection mirrors are
designed for a defined wavelength or wavelength
range. If the wavelength of the employed laser devi-
figure 2). The
ates from the specified value, the mirrors will not
work properly and can be destroyed.
Second for the mirror coatings also the allowed laser
rating is defined. If the specified values are exceeded,
destruction of the coatings might result (also see
section "Checking the Laser Parameters" on page
In addition the deflection mirrors are intended for a
specific beam diameter and a maximum allowed scan
angle. If the beam diameter or the scan angle exceeds
the specified maximum values, vignetting of the
beam can occur. The beam is then no longer fully
deflected by the mirrors or can no longer fully pass
through the objective. A portion of the beam is then
absorbed by the scan head, resulting in a loss of
power density at the edges of the image field.
Furthermore, the interior of the scan head and the
objective might be damaged due to the absorption of
laser radiation.
26).
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