A polymer scanner actuates a lens to achieve dynamic focusing of a laser spot on a target, while scanning a second lens to collect the reflected light. This synchronous scanning and detection enables extended range imaging of targets such as bar-codes, etc.

1. Koç University
Electromagnetically Actuated Optical Micro-
Mechatronic Systems Integrated on PCB
SerhanO. ISIKMAN
Advisor: Prof. Hakan Urey
http://mems.ku.edu.tr
http://www.serhanisikman.com 1

2. FR4 Technology: Printed Circuit Boards
(PCBs) as Actuated Platforms
 FR4 (Flame Retardant – Type 4) is the main substrate used in today’s
PCBs
 PCB sheets can be cut in the desired shape with high precision (<30um
precision) using standard, cost-effective PCB technology
 Different structural thicknesses available for design flexibility: 130um,

3. FR4 Technology: Main Advantages
 Uses existing standard PCB technology
 Comes with a seed copper layer suitable for electrical
interconnects, electro-magnetic actuation, and electro-
deposition of other metals (e.g. Nickel, permalloy)
 Well engineered material with excellent
electrical, thermal, and mechanical properties
 Compliant but strong material: Allows large deflections at
low frequencies, without vacuum !
 Can integrate electrical, mechanical, and optical
components on the same board for improved robustness
and form factor

4. Large scan-angle is achieved over an extended
depth-of-field using the FR4 scanner technology
Collection lens:
collects the light that is reflected off the
object-of-interest, and focuses it to an on-
chip, die-level detector underneath. Note
that the detector is powered through the
interconnects on the PCB platform, which is Torsionalflexures:
an additional flexibility of FR4 scanners (stress-resistant design to bear
large—angle deflections)
Opto-mechanical holder:
to mount the synchronously
scanned lenses
Focusing lens:
focuses the laser-light to a
distance, which is dynamically
changed as the laser is
actuated in/out of plane
Electro-coil:
“Laser-plunger”: to actuate the scanner in torsion
flexures actuate the VCSEL out-of-planew.r.t. the mode (for scanning) resonantly at
focusing lens for changing the focal-plane of scanning 50 Hz

5. Large scan-angle is achieved over an extended
depth-of-field using the FR4 scanner technology
(moving magnet
(moving magnet
scheme)
scheme)
Torsion @ 60 Hz Plunger @ 150 Hz

6. FR4 Laser Scanner with Dynamic Focusing
Dynamic Focusing Operation -
 Plunger is actuated in moving-coil fashion
 4 copper traces are patterned on the 500um wide plunger:
1 for laser diode (VCSEL), 3 for electro-magnetic actuation
 Plunger moves the laser diode out-of-plane with respect the lens to
modulate the beam waist location

7. FR4 Scanner with Scanned Detection + Dynamic
Focusing for Extended Depth-of-field Imaging

8. Barcodes with 125um lines are rapidly scanned over a 10cm
range, while more common bar codes (with 500um lines) are
scanned up to a 60cm range using the same bar-code reader
- experimental results -