Optical Microscanner Research Articles

Design and modeling of a novel electromechanical optical micro-scanner

This article presents a design principle of a novel small-sized compliant optical micro-scanner with two translational (X, Y) and a rotational (θz) degree of freedoms (3-DOFs). A novel normal-stress electromagnetic actuator system is proposed to provide 3-DOFs actuating forces with the working strokes of hundreds of microns for the optical micro-scanner within a very compact structural envelope. The electromagnetic actuator system can not only generate high actuating force density which is similar to solenoid, but also has linear force-current relations along three actuating axes by adopting magnetic configuration design strategy. The theoretical analysis model of the actuator system is derived by using equivalent magnetic circuit method and the actuating force is analyzed through energy store method. Permanent magnet flux leakage and magnetic saturation of stator core in excitation situation are taken into consideration to improve the modelling accuracy. Finite element analysis (FEA) software is utilized to investigate the critical characteristics of the micro-scanner. By FEA comparison, both the theoretical and FEA results show that the actuating force generated by the designed electromagnetic actuator system has a linear relationship with the excitation current. Compare with the normal optical micro-scanner actuated by voice coil motors (VCMs) or piezoelectric (PZT) actuators, the normal-stress based micro-scanner can not only offer movements with three degrees of freedom within a very compact structural envelope, but also achieve high actuating forces which are over 6 times higher than the same sized VCM-actuated micro-scanners. The workspace of this scanner is more than 800 × 800 μm2, which is more than 8 times larger than that of PZT-actuated scanner. The volume of this stage is 60 * 60 * 14 mm3, resulting in a high area-ratio of 1.2%. The cross-axis coupling motion is less than 24 μm at the full primary motion. The resonant frequencies of the two working axes are about 184 Hz.

Temperature dependence of the scanning performance of an electrostatic microscanner

An optical microscanner is one examples of an optical-MEMS device, which scans a laser beam across one or two dimensions by reflecting it. The microscanner has a range of applications, such as laser printers, laser displays and bio-medical imaging. For each application, the mirror is required to oscillated at a certain frequency and optical scan angle. However, its scanning performance varies with temperature. To address this issue, the temperature dependence of the natural frequency of a 1D electrostatic microscanner formed of single-crystal silicon is investigated both theorectically and experimentally in this paper. As the temperature rises from 30 °C to 80 °C, the calculated value of the natural frequency decreased from 1910.81 Hz to 1908.68 Hz, and the experimental value decreased from 2123.85 Hz to 2120.56 Hz. The percentage changes in calculated and experimental results were −0.11% and −0.15%, and thus the former was consistent with the latter. The factors of the variation of natural frequency are the deformation caused by thermal expansion and the temperature dependence of shear modulus. The results of theoretical calculations indicated that the principal factor in the change of natural frequency was the shear modulus on the temperature.

Optical Microscanner Using a Pair of Thermal Microactuators with Alternating Drive

Prototypes of optical microscanners using a pair of thermal microactuators have been designed, fabricated and evaluated. A micromirror with an area of 200×200µm is suspended by a pair of serpentine beams which are connected to a pair of thermal microactuators. The tilted angle of the mirror was simulated using FEM simulator Intelli Suite to optimize the beam parameters. The measured scan angle was about ±1.8°, which agreed reasonably well with the simulated results.

High-Throughput and Low-Cost Fabrication of Polymer Microscanner for Lighting Applications

A high-throughput and low-cost fabrication process for an optical microscanner is proposed for lighting applications. The process utilizes mold replication and transfer of printed functional layers to form a film. We confirmed that a high-throughput fabrication lasting less than 30 s could be obtained by using a mold with a knife edge. A polymer microscanner with feature size of 0.6×2 mm2 was successfully fabricated using our process. The scanner was actuated by magnetic forces generated by an external coil, and the mirror tilt angle was successfully measured by a strain gauge formed by the functional layer transfer. By synchronizing the LED input signal and the polymer scanner tilt angle, the illuminance distribution could be controlled. For example, this distribution could be expanded from 10 to 50° or divided into two separated spots. We believe that our developed process can address new MEMS applications such as commercial lighting.

Polymeric (SU-8) optical microscanner driven by electrostatic actuation

A torsional micromechanical scanner was fabricated using photosensitive polymer (SU-8). The scanner consists of two parts; top layer (micro mirror) and bottom layer (an anchor and electrodes). The SU-8 scanner is actuated by electrostatic force generated from the gap-closing electrodes. For the fabricated optical scanner with the mirror area of 3×3 mm2, the experimentally determined scanning angles were 0.85° and 3.1° for 60Hz (non-resonant) and 1.13 kHz (resonant) driving frequencies, respectively, at an input voltage of 160V. A polymer-based actuator offers advantages including a low-cost fabrication process and low frequency operation.

Single-cell bacteria growth monitoring by automated DEP-facilitated image analysis

Growth monitoring is the method of choice in many assays measuring the presence or properties of pathogens, e.g. in diagnostics and food quality. Established methods, relying on culturing large numbers of bacteria, are rather time-consuming, while in healthcare time often is crucial. Several new approaches have been published, mostly aiming at assaying growth or other properties of a small number of bacteria. However, no method so far readily achieves single-cell resolution with a convenient and easy to handle setup that offers the possibility for automation and high throughput. We demonstrate these benefits in this study by employing dielectrophoretic capturing of bacteria in microfluidic electrode structures, optical detection and automated bacteria identification and counting with image analysis algorithms. For a proof-of-principle experiment we chose an antibiotic susceptibility test with Escherichia coli and polymyxin B. Growth monitoring is demonstrated on single cells and the impact of the antibiotic on the growth rate is shown. The minimum inhibitory concentration as a standard diagnostic parameter is derived from a dose-response plot. This report is the basis for further integration of image analysis code into device control. Ultimately, an automated and parallelized setup may be created, using an optical microscanner and many of the electrode structures simultaneously. Sufficient data for a sound statistical evaluation and a confirmation of the initial findings can then be generated in a single experiment.

Low speed piezoelectric optical microscanner actuated by piezoelectric microcantilevers usingLaNiO3 bufferedPb(Zr,Ti)O3 thin film

We have developed piezoelectric optical microscanners for lowspeed scanning actuated by piezoelectric microcantilevers usingLaNiO3 (LNO)buffered Pb(Zr,Ti)O3 (PZT) thin films. The microscanners were fabricated from multilayers of Pt/LNO/PZT/LNO/Pt/Ti/SiO2 deposited on silicon on insulator (SOI) wafers through a microelectromechanical system(MEMS) microfabrication process. The microcantilevers were also fabricated through the samemicrofabrication process. Using the microcantilevers, we investigated the actuation conditionsfor the microscanners. We found that the microscanners actuated under non-resonant ACactuation need DC bias application to realize the mirror rotation. Application of 10 V ofDC bias resulted in a linear increase in the mirror rotation angle with the amplitude of theAC actuation voltage. The mechanical half rotation angle of the mirror reached5.3° under actuation byan AC voltage of 20 Vpp–30 Hz and a DC bias of 10 V.

Two-dimensional optical micro-scanner on silicon technology

A two-dimensional optical micro-scanner, which main components are two mobile flat and a concave micro-mirrors, is designed such that, all optical components can be fabricated on the same substratum. The optical parameters, which physical dimensions are between 50 and 500 μm, are obtained within the geometrical optics. The optical performance is evaluated by means of the MTF and Rayleigh resolution criteria, given 80% of modulation for a frequency of 8 cycles/mm with a Gaussian source, the resolution limit is 30 μm.

Tunable Optical Microscanner Driven by Piezoelectric Actuator

In this study, we developed a tunable piezoelectric optical microscanner. The characteristic of the present microscanner is that the Pb(Zr,Ti)O3 film is formed on the torsion hinges of the scanner and the hinges act as a tuner themselves. DC voltage applied to the tuner varies the resonant frequency of the rotation of the mirror. A laser displacement meter measures the resonant frequencies to be 6457 Hz for no tuning and 6471 Hz for 15 V tuning. The resonant frequency with tuning between 0 and 15 V shows a hysteresis curve. Moreover, tuning between -15 and 15 V results in the butterfly curve of resonant frequency. The scanning angle under resonant actuation at 6457 Hz is decreased from 5.6 to 5.0° by applying a DC voltage of 15 V to the tuner. The result is in good agreement with the displacement of the edge of the mirror measured using the laser displacement meter.

Smart optical microscanner with piezoelectric resonator, sensor, and tuner using Pb(Zr,Ti)O3 thin film

The present study describes the design, fabrication, and demonstration of the optical microscanner with a piezoelectric resonator, sensor, and tuner: a smart optical microscanner. Pb(Zr,Ti)O3 thin film is deposited not only on the resonators but also on the hinges to act as the sensor or tuner. dc voltage applied to the tuner has shifted the resonant frequency and the sensor has successfully detected the shift of the resonant frequency. Though the frequency shift is only 1Hz∕V and the signal from the sensor is noisy, the results indicate the potential of the smart optical microscanner.

High-speed metal-based optical microscanners using stainless-steel substrate and piezoelectric thick films prepared by aerosol deposition method

High-speed metal-based optical microscanning devices were successfully fabricated in combination with piezoelectric thick films directly deposited by the aerosol deposition method (ADM) and specially designed stainless steel frame. A large optical scanning angle (41°) was achieved at a high resonance frequency (28.24 kHz) in ambient air without vacuum packaging. The well-polished metal-based mirror has good flatness of less than 105 nm, which is lower than λ/4. The metal-based microscanners enable faster scanning, higher scanning angles, lower production cost, and simpler fabrication processes.

A Method to Measure Beam Deflections in Different Resonance Modes Piezoresistively and its Incorporation into 2D Optical Microscanners

This paper describes a sensing technique to detect beam deflections caused by the two different vibration modes, i.e. bending and torsion modes of a micro cantilever, separately with two piezoresistor bridge circuits. Fabrication process to incorporate this detection circuitry into a two-dimensional optical microscanner together with the signal processing circuitry for self-sustaining vibrations are presented, which enables a compact feedback control of the two-dimensional optical scanning. Prototype optical scanners with this detection circuitry and magnetostirictive actuation have been fabricated with MEMS technology and tested to verify this technology.

High-Speed Optical Microscanner Driven with Resonation of Lam Waves Using Pb(Zr,Ti)O3 Thick Films Formed by Aerosol Deposition

A high-performance optical microscanner with a resonance frequency over 20 kHz and a scan angle (peak-to-peak value) over 30° in atmospheric ambient, was successfully fabricated by deposit piezoelectric materials at a high rate by the AD method onto a metal scanner structure, which was fabricated by mechanical machining. The scanner is applicable to SVGA high-resolution display of 800×600 or more. This method is a powerful tool for realizing ceramic integration with metal components.

9002 高速光スキャナーの有限要素解析(GS-A1 一般セッション(製造関連解析技術))

9002 高速光スキャナーの有限要素解析(GS-A1 一般セッション(製造関連解析技術))

P2-50 Time transient analysis of a high speed optical microscanner(Short presentation for poster)

P2-50 Time transient analysis of a high speed optical microscanner(Short presentation for poster)

A novel actuation mechanism on the basis of ferromagnetic SMA thin films

A novel actuation mechanism is presented, which makes use of the antagonism of intrinsic magnetic and shape recovery forces acting on a ferromagnetic shape memory alloy (SMA) microactuator in a magnetic field. This mechanism is associated with large actuation and small biasing forces in each actuation direction resulting in a large stroke. Since no additional biasing elements are required, extremely compact designs are possible. As a demonstrator, an optical microscanner of 7 mm×3 mm×5 mm size is presented showing large scanning angles up to 120° in off-resonance mode. The scanning performance keeps frequency independent below a critical frequency, which is determined by heat transfer times.

STUDY ON BIMORPH AND MULTIMORPH MICROACTUATORS

International Journal of Computational Engineering ScienceVol. 04, No. 02, pp. 215-219 (2003) Actuators and SensorsNo AccessSTUDY ON BIMORPH AND MULTIMORPH MICROACTUATORSAJAY AGARWAL, TERENCE GAN, JANAK SINGH, YUE K. HOH, and ANDREW A. O. TAYAJAY AGARWALInstitute of Microelectronics, 11 Science Park Road, Singapore Science Park II, Singapore 117685, Singapore Search for more papers by this author , TERENCE GANInstitute of Microelectronics, 11 Science Park Road, Singapore Science Park II, Singapore 117685, Singapore Search for more papers by this author , JANAK SINGHInstitute of Microelectronics, 11 Science Park Road, Singapore Science Park II, Singapore 117685, Singapore Search for more papers by this author , YUE K. HOHDepartment of Mechanical Engineering, National University of Singapore, Singapore Search for more papers by this author , and ANDREW A. O. TAYDepartment of Mechanical Engineering, National University of Singapore, Singapore Search for more papers by this author https://doi.org/10.1142/S1465876303000934Cited by:0 PreviousNext AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsRecommend to Library ShareShare onFacebookTwitterLinked InRedditEmail AbstractThis paper presents the simulation and the experimental results of various bimorph and multimorph structures, which are formed using Si, SiO2, and Al. These results include effects of thickness variation of the single/ composite material. The effect of multiple heat cycles, on the stress of various structural materials is investigated. The cantilever tip bending mainly due to intrinsic stresses, is measured using Optical Interferometer and compared with the simulated data which is obtained by an analytical model developed using ANSYS. A combination of various materials is predicted that are suitable for released cantilevers with variable bending. Finally, the bimorph and multimorph structures that have yielded the high and low intrinsic stresses are also discussed.Keywords:BimorphCantileverintrinsic stresscoefficient of thermal expansion References S. P. Timoshenko, Journal of the Optical Society of America 11, 233 (1925). Crossref, Google ScholarW. Riethmuller and W. Benecke, IEEE Trans. Electron Devices 35, 758 (1988). Crossref, Google Scholar C. Doering, T. Grauer, J. Marek, M. S. Mettner, H.-P. Trah and M. William, Micromachined thermoelectrically driven cantilever structures for fluid deflection, Proc. Micro Electromechanical Systems '92 (Travemuende) (1992) 12-18 . Google ScholarJ. Buehleret al., Sensors Actuators A 46-47, 572 (1995). Google Scholar S. Schweizer, P. Cousseau, S. Calmes and Ph Renaud, Two dimensional thermally actuated optical microscanner Proc. Eurosensors XIII (The Hague) (1999) 11-12 . Google Scholar FiguresReferencesRelatedDetails Recommended Vol. 04, No. 02 Metrics History KeywordsBimorphCantileverintrinsic stresscoefficient of thermal expansionPDF download

Magnetically-driven bi-directional optical microscanner

A magnetically-driven bi-directional optical microscanner has been designed, fabricated and characterized. Magnetic and structural modeling and analysis has been applied to the design of the scanner. The micromachined scanner can be operated bi-directionally under the condition of static operation. Under dynamic operation, the prototype scanner has shown stable bi-directional scanning performance at the operating frequency of 30 Hz, corresponding to 60 Hz in the regular uni-directional scanner. Compared with a conventional scanner, the microscanner has the advantages of low power consumption due to its small size and high scanning efficiency as a result of unique bi-directional actuation.

Thermally actuated optical microscanner with large angle and low consumption

A monolithic silicon integrated optical micro-scanner is presented. The device consists of a mirror located on the tip of a thermal bimorph actuator beam. The fabrication process is very simple and compatible with IC fabrication techniques. The device is excited electrothermally at its resonance frequency, enabling large angular deflections at low power consumption. The technological process consists of basic frontside silicon micromachining steps requiring only three mask levels. The moving part is defined by selective silicon bulk etching. The bimorph beam is made of silicon dioxide and a thin film conductor. The residual stress in the two layers is used to achieve a 45° out-of-plane rest position of the mirror. This allows optical components (e.g., laser diode, collimating lens) to be placed directly on the silicon substrate. Mirrors of 500×300 to 800×800 μm 2 with resonant frequencies varying from 600 to 100 Hz were realized. Mechanical scan angles of above 90° were achieved. The devices are very robust and have run through fatigue tests of billions of cycles at 300 Hz and 90° deflection. The power consumption of the device is typically 1 mW for 30° mirror deflection.