1
M.S. Research (2006-2008)M.S. Research (2006-2008)Electromagnetically Actuated Electromagnetically Actuated Optical Micro-Mechatronic Optical Micro-Mechatronic Systems Integrated on PCB Systems Integrated on PCB
Serhan O. ISIKMAN
Advisor: Prof. Hakan Urey
http://mems.ku.edu.trhttp://www.serhanisikman.com
Koç University
1) Scanned-detection drastically improves signal-to-noise ratio (SNR)
Conventional Systems: The laser spot is scanned across an object (e.g. a bar-code), and the detection optics is static.
The presented system: The collection-lens is scanned synchronously with the mirror that is used to scan the laser-spot to increase SNR.
detected signal with a conventional system
detected signal with the scanned detection system
same barcode
LD
LD
75 mm
650 mm
500 um
500 μm displacement of the light-source with respect to a fixed lens (f= 6mm) results in about 600mm displacement of the focused spot position. In most scanning platforms, actuating an integrated light source w.r.t. to a fixed lens is challenging
f = 6 mm
fdido111
Imaging Equation
2) Achieving dynamic focusing would allow scanning objects within a long depth-of-field, i.e. close objects as well as distant ones
FR4 SCANNERS:
A new opto-electro-mechanical system platform for highly integrated AND
miniaturized scanning and imaging systems
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, 200um, 250um, 300um …
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 for excellent electrical, thermal, and mechanical properties
Compliant but strong material: Allows high deflections at low frequencies, without vacuum !
Can integrate electrical, mechanical, and optical components on the same board for improved robustness and form factor
Large scan-angle is achieved over an extended depth-of-field using
the FR4 scanner technology
S-shaped torsional flexures: (stress-resistant design to bear large—angle deflections)Opto-mechanical holder:to mount the synchronously scanned lensesFocusing lens:focuses the laser-light to a distance, which is dynamically changed as the laser is actuated in/out of plane
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 an additional flexibility of FR4 scanners
Electro-coil: to actuate the scanner in torsion mode (for scanning) resonantly at 50 Hz
“Laser-plunger”: to actuate the VCSEL out-of-plane for changing the focal-plane of scanning
Large scan-angle is achieved over an extended depth-of-field using
the FR4 scanner technology
Torsion @ 60 Hz Plunger @ 150 Hz
(moving magnet scheme)
(moving magnet scheme)
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 out-of-plane to modulate the beam waist location
Electromagnetic Actuation Schemes Utilized in FR4 Scanners
H2H1
S NMFN
Fs
€
T =V ⋅M⋅H⊥LiBF
N
kkkrFT
12
- MOVING MAGNET - - MOVING COIL-
FR4 Scanner with Scanned Detection + Dynamic Focusing for Extended
Depth-of-field Imaging
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 -
Patents & Publications1. S. O. Isikman, R. B. Sprague, H. Urey, " Advanced imaging
with dynamic focus and extended depth using integrated FR4 platform", Optics Express, Vol. 17, Issue 19 (2009)
2. S. O. Isikman, H. Urey, “Dynamic Modeling of Soft Magnetic Film Actuated Scanners”, IEEE Transactions on Magnetics, Volume 45, Issue 7, pp: 2912 - 2919 (2009)
3. S. O. Isikman, R. B. Sprague, H. Urey, “FR4 Laser Scanner with Dynamic Focus”, IEEE Photonics Technology Letters, vol.21, no.4 (2009)
4. S. O. Isikman, et al., “Self-Oscillating FR4 Laser Scanner with Integrated Dynamic Focus and Extended Imaging Range”, to be presented in International Symposium on Opto-mechatronic Technologies, Istanbul, Turkey (2009)
5. H. Urey, S. O. Isikman, S. Holmstrom, “MEMS and FR4 Scanners for Micro-display and Imaging Applications (Invited Paper),” ICMEMS Conference, Chennai, India, (2009)
6. S. O. Isikman, O. Ergeneman, A.D. Yalcinkaya, H. Urey, “Modeling and Characterization of Soft Magnetic Film Actuated 2D Scanners,” Journal of Selected Topics in Quantum Electronics, Vol. 12, pp.283-289, Mar/Apr. 2007
7. S. O. Isikman, H. Urey, “Dynamic Modeling of Magnetic Film Actuators”, IEEE LEOS Special Symposium on Optical MEMS and NEMS, Orlando, USA, Nov 2007
8. S. Holmstrom, A. D. Yalcinkaya, S. O. Isikman, C. Ataman, H. Urey, “FR-4 as a New MOEMS Platform”, IEEE-LEOS Optical MEMS Conference, p.25-26, Hualien, Taiwan, August 2007
9. H. Urey, A. Yalcinkaya, S. O. Isikman, S. Holmstrom “Electromagnetic Actuators for Scanners (Keynote Paper),” Eurosensors XX Conference, Göteborg, Sweden, Sep. 2006
