US Patent 9086516 Light-guide apparatus

A light-guide apparatus comprising a light-guide plate for guiding light rays and a plurality of light extraction features is described. The light extraction features comprise a transparent material applied to the light-guide plate so as to form an uneven surface. The transparent material may comprise a textured ink applied to the surface of the light-guide plate via a printing process. The incorporation of an uneven surface provides micro-lens like elements on the surface of the extraction feature which have a higher aspect ratio and so lend themselves to the refraction of the light out of the light-guide plate. In this way a device is produced wherein the size, height, location and surface profile of the extraction features can be carefully controlled. As a result the described light-guide apparatus provides for a highly efficient and relatively uniform light output.