Compact triangulation sensor realized by bending Si wafer with optical elements at metal hinges

A triangulation distance sensor is constructed bending the wafer with metal hinges. On the Si wafer, elements are pre-aligned at the planer condition using the photolithography. The position sensitive detector (PSD), mirror, and alignment pit for a ball lens are prepared. 3-sensor array is integrated in 20×17×10 mm³ size. Compared with our previous study using polymer, the metal hinge stabilizes the long-term performance and the process. Optical elements including LD chip are all included on the wafer. The demonstrated measurement range is 18-40 mm.