Illumination systems employing multi-layer laminated sheet-form optical structures with embedded tir channels

An illumination system, comprising:

• a lighting module comprising a plurality of light emitting diodes (LEDs);
• a flexible optically transmissive sheet disposed in an energy receiving relationship with respect to the lighting module, the flexible optically transmissive sheet having a multi-layer laminated structure, a generally rectangular shape, and a thickness between 200 micrometers and 1 millimeter, the flexible optically transmissive sheet comprising:
• a first layer of an optically transmissive material,
• a regular array of linear channels formed in the first layer, the linear channels in the regular array extending parallel to one another between two edges of the flexible optically transmissive sheet, each of the linear channels in the regular array defining a pair of side walls configured to reflect light using total internal reflection,
• a textured optically transmissive layer coextensive with the first layer and having a textured outer surface, and
• an optically transmissive adhesive layer coextensive with the first layer and the textured optically transmissive layer, the optically transmissive adhesive layer being disposed between the first layer and the textured optically transmissive layer;
• and
• a broad-area reflective surface disposed in direct or indirect energy receiving relationship with respect to the flexible optically transmissive sheet and configured to reflectively scatter light,
• wherein at least some of the linear channels are separated from one another by surface portions of the first layer bonded to a surface of the textured optically transmissive layer using the optically transmissive adhesive layer.

A method of making an illumination system, comprising:

• providing a lighting module comprising a plurality of light emitting diodes (LEDs);
• providing a flexible optically transmissive sheet, the flexible optically transmissive sheet having a multi-layer laminated structure, a generally rectangular shape, and a thickness between 200 micrometers and 1 millimeter, the flexible optically transmissive sheet comprising:
• a first layer of an optically transmissive material,
• a regular array of linear channels formed in the first layer, the linear channels in the regular array extending parallel to one another between two edges of the flexible optically transmissive sheet, each of the linear channels in the regular array defining a pair of side walls configured to reflect light using total internal reflection,
• a textured optically transmissive layer coextensive with the first layer and having a textured outer surface, and
• an optically transmissive adhesive layer coextensive with the first layer and the textured optically transmissive layer, wherein the optically transmissive adhesive layer is disposed between the first layer and the textured optically transmissive layer, and wherein at least some of the linear channels are separated from one another by surface portions of the first layer bonded to a surface of the textured optically transmissive layer using the optically transmissive adhesive layer;
• disposing the flexible optically transmissive sheet in an energy receiving relationship with respect to the lighting module;
• providing a broad-area reflective surface configured to reflectively scatter light;
• and
• positioning the broad-area reflective surface in direct or indirect energy receiving relationship with respect to the flexible optically transmissive sheet.