Micromachined 2-D scanner for 3-D optical coherence tomography

With the inherent advantages of micromachining technologies such as small size, small mass, low cost, low power consumption and high reliability, there will be radical changes to biomedical devices and how clinical diagnoses are made. One of the most promising applications of microtechnologies is in the field of medical science. This paper presents a potentially low voltage high electrostatic torque micromachined mirror capable of two-dimensional (2-D) scans (simultaneous transverse and longitudinal scans) for optical coherence tomographic imaging. When the micro-mirror is integrated with an optical coherence tomography (OCT) system, three-dimensional (3-D) sample images can be obtained in one longitudinal scan period. 3-D images of internal-organs of fruit fly (Drosophila melanogaster) and its larva are acquired using the micromachined-based OCT system. The dimension of the micromachined mirror is 1000 um × 1000 um. The entire MEMS scanner is made of single-silicon crystal, to act as mechanical reinforcement counteracting the inherent stresses of the deposited thin films on the mirror. The scanning mirror is actuated electrostatically.