Miniature Flipping Disk Device for Size Measurement of Objects Through Endoscope

Finding the size and distance of objects viewed through a single optical path-a typical endoscopic condition-is a challenge. Stereo imaging, which would provide the size and distance information, typically requires multiple optical channels or other elaborate techniques, increasing the endoscope diameter and system complexity. This paper reports the development of a miniature flipping disk device that enables stereo measurement, and demonstrates the operation of the device installed in an endoscope. The fabricated Pyrex disk (1.2 mm in diameter and 485 μm in thickness), anodically bonded to a 50-μm-thick silicon vertical comb-drive actuator, is flipped to ±10.7° at a resonant frequency of 414 Hz by 10 V_AC of electrostatic actuation. The image shift made by such glass flipping provides a reference dimension, against which the real size and distance of objects seen through a standard single-channel endoscope can be estimated.