Traditionally, in optical devices used for fingerprint recognition, light-shielding layers are disposed on both sides of a collimator to prevent incident light from leaking into neighboring pixel regions. For example, it is one of the ways to set multi-layered light-shielding layers on both sides of the collimator to try to solve the above-mentioned light leakage problem. The multi-layered light-shielding layer is formed by stacking black light-shielding material layers and transparent material layers on top of each other. Although the light-shielding layer is relatively simple to fabricate, since the black light-shielding material layers and the transparent material layers are stacked on top of each other, it is still possible for light entering the collimator to leak from the transparent material layers on both sides of the collimator into neighboring pixel regions by means of refraction or diffraction, which can cause further interference with the light reception of the neighboring pixel regions. From this point of view, this design does not really solve the problem of cross-talk interference.
Therefore, development of an optical device having an optimal collimation effect and capable of avoiding cross-talk, and a related fabrication method thereof, is desirable.