Jui-che Tsai

The Evolution of MEMS Displays

Due to the advancement of microoptoelectromechanical systems and microelectromechanical systems (MEMS) technologies, novel display architectures have emerged. One of the most successful and well-known examples is the Digital Micromirror Device from Texas Instruments, a 2-D array of bistable MEMS mirrors, which function as spatial light modulators for the projection display. This concept of employing an array of modulators is also seen in the grating light valve and the interferometric modulator display, where the modulation mechanism is based on optical diffraction and interference, respectively. Along with this trend comes the laser scanning display, which requires a single scanning device with a large scan angle and a high scan frequency. A special example in this category is the retinal scanning display, which is a head-up wearable module that laser-scans the image directly onto the retina. MEMS technologies are also found in other display-related research, such as stereoscopic (3-D) displays and plastic thin-film displays.

Dental optical coherence tomography.

This review paper describes the applications of dental optical coherence tomography (OCT) in oral tissue images, caries, periodontal disease and oral cancer. The background of OCT, including basic theory, system setup, light sources, spatial resolution and system limitations, is provided. The comparisons between OCT and other clinical oral diagnostic methods are also discussed.

Gimbal-less MEMS two-axis optical scanner array with high fill-factor

In this paper, we report on a MEMS-based two-axis optical scanner array with a high fill factor (>96%), large mechanical scan angles (/spl plusmn/4.4/spl deg/ and /spl plusmn/3.4/spl deg/), and high resonant frequencies (20.7 kHz). The devices are fabricated using SUMMiT-V, a five-layer surface-micromachining process. High fill factor, which is important for 1/spl times/N/sup 2/ wavelength-selective switches (WSSs), is achieved by employing crossbar torsion springs underneath the mirror, eliminating the need for gimbal structures. The proposed mirror structure can be readily extended to two-dimensional (2-D) array for adaptive optics applications. In addition to two-axis rotation, piston motion with a stroke of 0.8 /spl mu/m is also achieved. [1496].

1/spl times/N/sup 2/ wavelength-selective switch with two cross-scanning one-axis analog micromirror arrays in a 4-f optical system

A new high-port-count wavelength-selective switch (WSS) has been realized using two cross-scanning one-axis analog micromirror arrays in a 4-f optical system. The number of output ports is increased from N to N/sup 2/, where N is the maximum linear port count limited by optical diffraction. Using surface-micromachined micromirrors with hidden vertical comb drives, large scan angles (>/spl plusmn/5/spl deg/ mechanical), low drive voltages (7 V), and high fill factors (> 96.25%) are achieved for both scanning mirrors. Experimental results for WSS are demonstrated using both two-dimensional (2-D) array of discrete collimators and monolithic 2-D collimator array. A fiber-to-fiber insertion loss ranging from 6 to 18 dB and a switching time of <700 /spl mu/s have been achieved.

Design, Fabrication, and Characterization of a High Fill-Factor, Large Scan-Angle, Two-Axis Scanner Array Driven by a Leverage Mechanism

We report on the design, fabrication, and characterization of a high fill-factor, large scan-angle, two-axis scanner array. The two-axis microelectromechanical-systems (MEMS) mirror is driven by electrostatic vertical comb-drive actuators through four motion amplifying levers. The maximum mechanical rotation angles are

A high port-count wavelength-selective switch using a large scan-angle, high fill-factor, two-axis MEMS scanner array

pm 6.7^circ

Two-axis MEMS scanners with radial vertical combdrive actuators : design, theoretical analysis, and fabrication

at 75 V for both axes, leading to total optical scan angle of 26.8

Linearization of a two-axis MEMS scanner driven by vertical comb-drive actuators

^circ

A MEMS Doubly Decoupled Gyroscope With Wide Driving Frequency Range

. The resonant frequency is 5.9 kHz before metallization. A linear fill factor of 98% is achieved for the one-dimensional (1-D) micromirror array. This 1D array of two-axis micromirrors was designed for

Recovery of stiction-failed MEMS structures using laser-induced stress waves

1times N ^2