An optical proximity sensor arrangement comprises a semiconductor substrate (100) with a main surface (101). A first integrated circuit (200) comprises at least one light sensitive component (201). The first integrated circuit is arranged on the substrate at or near the main surface. A second integrated circuit (300) comprises at least one light emitting component (301), and is arranged on the substrate at or near the main surface. A light barrier (400) is arranged between the first and second integrated circuits. The light barrier being designed to block light to be emitted by the at least one light emitting component from directly reaching the at least one light sensitive component. A multilayer mask (500) is arranged on or near the first integrated circuit and comprising a stack (501) of a first layer (502) of first elongated light blocking slats (503) and at least one second layer (504) of second elongated light blocking slats (505). The light blocking slats are arranged in the mask to block light, incident on the mask from a first region of incidence (701), and to pass light, incident on the mask from a second region of incidence (702), from reaching the at least one light sensitive component.