An optical module including a light source and an optical sensor is provided. The optical sensor includes a pixel matrix and an opaque layer. The pixel matrix includes a plurality of unblocked pixels, a plurality of first pixels and a plurality of second pixels. The opaque layer covers upon a first region, which is a part of each first pixel, and upon a second region, which is a part of each second pixel, but does not cover upon the unblocked pixels, wherein the first region and the second region are symmetrically arranged in a first direction, and uncovered regions of the first pixels and the second pixels are arranged to be larger at a pixel edge than at a pixel center.