Compact triangulation sensor array constructed by wafer bending

An optical triangulation distance sensor array was constructed by bending a silicon wafer. Since bending is the final process in the fabrication sequence, planar photolithography can be included in the fabrication sequence. The elements on the Si wafer are all prealigned under a planar condition, and the position-sensitive detector, mirror, and alignment pit for the collimation ball lens are prepared before bending the wafer. The size of the optical bench produced by the sensor substrate is 1.4 mm deep. By batch fabrication, a 2 × 2 sensor array was produced. A dynamic range of 4 mm and a noise level of ±1 % was confirmed by testing.