Patent ID: 9025253
Filing Date: 2015-05-05
Classification: G02B

Abstract:
1. An optical device, comprising: a light-transmitting substrate having a first part including an input aperture surface, a second part including an output aperture surface and at least first and second major surfaces parallel to each other and edges; at least one partially reflecting surface for coupling out light waves from the substrate, the partially reflecting surface being located in the second part of the substrate and is nonparallel to the major surfaces of the substrate; optical means, outside of the substrate, for changing the direction of incident light waves impinging on the optical means so that the light waves are trapped inside the substrate by total internal reflection, and wherein the optical means has an output aperture surface, the output aperture surface of the optical means being optically cemented to the input aperture surface of the substrate, the first part of the substrate between the two major surfaces located next to the substrate input aperture surface, including the input aperture surface being substantially transparent, the trapped light waves passing through the output aperture surface without any substantial reflection from one of the first and second major surfaces of the substrate, the only optical element inside the substrate being the at least one partially reflecting surface located in the second part of the substrate and the input aperture surface of the substrate being located at one of the two major surfaces of the substrate.