A light shielding layer 11 is disposed on the substrate 10, and the light shielding layer 11 includes a plurality of through holes 111. The through hole 111 is circular in this embodiment, while the through hole 111 is not limited to be circular and may be rectangular, elliptical or the like in other embodiments. A plurality of light detection units 4 are disposed at a side of the light shielding layer 11 adjacent to the substrate, and the light detection unit 4 may be a photosensitive diode, a phototriode, a CCD or the like. As shown in FIG. 2, the light detection unit 4 is disposed on the substrate 10. In other embodiments, the light detection unit 4 is disposed on the light shielding layer 11, as long as the light detection unit 4 is disposed at a side adjacent to the substrate 10. The plurality of through holes 111 and the plurality of light detection units 4 are correspondingly disposed one by one, wherein “correspondingly disposed” means that a projection of the through hole 111 on the substrate 10 overlaps with a projection of the light detection unit 4 on the substrate 10. For example, projections of the light detection units 4 on the substrate 10 are all within projections of the through holes on the substrate 10, and further located at a central position of projections of the through holes 111 on the substrate 10.