Tohoku University Technology: Scanning mirror and its manufacturing method: T18-504

Torsion bar resistant to torsional fatigue! Vacuum sealing not needed but long life and low cost MEMS laser scanner

The micro-scanner which is being developed to reduce the LiDAR (Light Detection and Ranging) size is a MEMS device that has a mirror and a torsion bar to support it, and scans with the laser beam in 2D. So far, the torsion bar could break in a short time due to hydroxylation/oxidation caused by moisture/oxygen adhesion to its surface. In addition, even a standard protective film is formed on the torsion bar surface, it cannot completely prevent moisture and oxygen adhesion, so the degradation of the torsion bar cannot be avoided. As consequence, vacuum sealing of the mirror device was required to obtain a practical life of the torsion bar. 　This invention is able to provide a scanning mirror and its manufacturing method that can prevent deterioration from oxidation and hydroxylation of the torsion bar in the atmosphere. This invention is composed of a mirror section and a torsion bar in which the surface is covered with an ALD (Atomic Layer Deposition) layer.

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