Optical layer and optical system

An optical layer comprising:

• a structured first major surface and an opposite second major surface, the structured first major surface comprising a plurality of microlenses arranged along orthogonal first and second directions;
• and
• an embedded optically opaque first mask layer disposed between and spaced apart from the first and second major surfaces, the first mask layer defining a plurality of laser-ablated through first openings therein arranged along the first and second directions, there being a one-to-one correspondence between the microlenses and the first openings, wherein for each first opening in at least a majority of the first openings, the first opening defines a voided region having a maximum thickness greater than an average thickness of the first mask layer, wherein the average thickness of the first mask layer is t, the first openings have an average largest lateral dimension d, and t/d<0.05.

An optical layer comprising:

• a structured first major surface and an opposite second major surface, the structured first major surface comprising a plurality of microlenses arranged along orthogonal first and second directions;
• and
• an embedded optically opaque first mask layer disposed between and spaced apart from the first and second major surfaces, the first mask layer defining a plurality of laser-ablated through first openings therein arranged along the first and second directions, there being a one-to-one correspondence between the microlenses and the first openings, wherein for each first opening in at least a majority of the first openings, the first opening defines a voided region having a top major surface facing the first major surface and an opposite bottom major surface facing the second major surface, wherein in a cross-section of the optical layer substantially perpendicular to optical layer, the top and bottom surfaces have a separation closer to a center of the voided region greater than a separation closer to an edge of the voided region, and at least one of the top and bottom major surfaces has a surface roughness in a range of 10 nm to 200 nm.