Patent ID: 9726893
Date: 2017-08-08
CPC Classifications: G02B,G03B,G06T,H04N

Claim:
1. A compact optical see-through head-mounted display, capable of combining a see-through path with a virtual view path such that the opaqueness of the see-through path can be modulated and the virtual view occludes parts of the see-through view and vice versa, the display comprising: a. a microdisplay for generating an image to be viewed by a user, the microdisplay having a virtual view path associated therewith; b. a transmission-type spatial light modulator ( c. an objective optics, facing an external scene, configured to receive the incoming light from the external scene and to focus the light upon the spatial light modulator, where the objective optics is a three-reflection freeform prism, comprising five optical freeform surfaces: refractive surface S d. a beamsplitter configured to merge a digitally generated virtual image from a microdisplay and a modulated see-through image of an external scene passing from a spatial light modulator, producing a combined image; e. an eyepiece configured to magnify the combined image, where the eyepiece is a two-reflection freeform prism, comprising four optical freeform surfaces: refractive surface S f. an exit pupil configured to face the eyepiece, the exit pupil whereupon the user observes the combined view of the virtual and see-through views in which the virtual view occludes portions of the see-through view; wherein the objective optics is disposed upon a front layer of the display, where the spatial light modulator is disposed on the back layer of the display at or near an intermediate image plane of the see-through path, facing a side of the beam splitter where the microdisplay is disposed on the back layer of the display, facing a different side of the beam splitter where the beam splitter is disposed such that the see-through path is merged with the virtual view path and the light from the merged path is directed to the eyepiece wherein the eyepiece is disposed upon the back layer of the display, whereupon the incoming light from the external scene enters the objective optics through the refractive surface S