Analysis for the characteristic of a four-quadrant photo-detector applied to a novel laser aligning system

Abstract

A novel alignment method is provided for the mask-plate alignment with two four-quadrant photodetectors. The location of lasers and four-quadrant photo-detectors are fixed. The mask-plate, which is carried by a manipulator with an adjustable platform, is between the lasers and the four-quadrant photo-detectors. Through two transparent reticle alignment marks, the laser beam is projected onto the active area of the four-quadrant photo-detectors. According to the output signals of the four-quadrant photo-detectors, the errors of the mask's position and pose are calculated out. So the mask-plate's position and pose are adjusted to implement alignment by the mask-plate-transferring manipulator with the adjustable platform. The alignment algorithm and the ε-Δ characteristic curve were deduced. Show more