A compact and sensitive two-dimensional angle probe for flatness measurement of large silicon wafers

On-machine measurement of a cylindrical surface with sinusoidal micro-structures by an optical slope sensor

“…Fig. 7 shows a schematic of the sensor, which is based on the principle of autocollimation [24][25][26][27][28][29][30]. The p-polarization laser light from a laser diode is collimated to a beam with a diameter of 6 mm.…”

A surface motor-driven planar motion stage integrated with an XYθ surface encoder for precision positioning

“…The autocollimation unit consists of a lens and a position-sensing photo-detector placed at the focal plane of the lens. Quadrant photodiodes are used as the photo-detectors in the sensor for 2D detection [28,29]. The autocollimation allows for the angle-detection independent from the distance between the sensor unit and the angle grid surface.…”

Development of high-precision micro-roundness measuring machine using a high-sensitivity and compact multi-beam angle sensor

“…Compared with multi-orientation methods, multiprobe methods are more suitable for on-machine measurements because it does not depend on the repeatability of the spindle error [8][9][10].…”