Measurements of a fabricated micro mirror using a lateral-effect position-sensitive photodiode

The characteristics of a fabricated micro mirror were determined using an optical measurement-system. The system consisted of a helium-neon laser, a p-i-n lateral-effect photodiode, and other fundamental optical elements. For testing, we used a micro mirror array (1 x 4) in which each mirror was composed of a mirror plate, two torsional flexure hinges, two address electrodes, and two support posts. A mirror plate was designed to a size of 100 x 110 x 1.5 [[[micro]meter].sup.3] and the hinge size was 20 [[micro]meter] long, 5 [[micro]meter] wide, and 0.5 [[micro]meter] thick. The micro mirror array was fabricated using micromachining technology and a lithography-galvanoformung-abformung-like process using nickel electroplating. The variation in the mirror's deflection angle with applied voltage was measured as a static characteristic. The downward threshold voltage of the 0.5-[[micro]meter] thick hinge was 48 V. The step response time, as a dynamic characteristic, was 21.8 [[micro]seconds] when a 64-V step voltage higher than the downward threshold voltage was applied to an address electrode. The lifetime of the fabricated micro mirror was tested for both unidirectional and bidirectional operation. Index Terms - Lifetime, micro mirror array, optical measurement system, p-i-n lateral-effect photodiode.