Multi-axial confocal distance sensor using varifocal liquid lens

The paper repots on a multi-axial confocal distance sensor using a combination of varifocal liquid lens and a scanning mirror. The liquid lens can change its focal length only by applying a voltage. Thus the sensor can scan laser without using a long stroke actuators. From this point, the sensor size can be miniaturized to attach on hand-held observation equipment. We measured the surface posture of randomly arrayed bumps with the sensor and confirmed that the sensor can detect the posture with 1.65 mm error in its X-axis position and 0.11 mm error in its Z-axis position.