Ergonomic head mounted display device and optical system

An image display system which projects displayed virtual image into a pupil of a user through a waveguide prism, allowing the user to see displayed content overlaid upon a real world scene, where the system has a wide see-through field of view, of up to 90° in the temple direction, up to 60° in the nasal direction, and up to 60° above and below a straight-ahead view, and where the system fits into the shape of an eyeglass form factor, the system comprising:

• a. An image display unit 105, disposed towards the temple side of a users head, which projects light into a waveguide, where the image display unit is constrained to be outside of a reference curved surface defined by the shape of an average human head;
• b. an optional coupling lens group 110, disposed between the image display unit and a waveguide, composed of one or more lenses, which guide light from the image display unit 105 into the waveguide 100 and corrects for optical aberration;
• c. a transparent optical waveguide prism 100, which accepts the light from the image display unit and propagates the light until the, image is projected into the field of view of the user;
• where the waveguide has. a physical inner surface 115, physical edge surface 120 and physical outer surface 125, a first refractive surface 130, and a second refractive surface 135, and a plurality of reflective surfaces, where the waveguide has a shape that fits into an eyeglass form factor and has a wide see-through field of view of up to 90° in the temple direction, up to 60° in the nasal direction, and up to 60° above and below a straight-ahead view;
• d. a compensation lens 160, secured to the physical outer surface 125 of the waveguide 100, which corrects for optical distortion caused by viewing the world through the waveguide prism;
• where the inner surface of the compensation lens 165 approximates the shape of the outer surface 125 of the waveguide;
• where a small air gap 195 is maintained between the compensation lens and the waveguide on surfaces where the total internal reflection criterion is satisfied for the outer surface 125 of the waveguide;
• whereupon the image display unit 105 transmits light 140 into the optional coupling lens 110 followed by the waveguide 100, or into the waveguide directly, through a first refractive surface 130;
• whereupon the light 140 follows a path 145 along the waveguide that comprises a plurality of reflections from the first refractive surface 130 to the second refractive surface 135;
• whereupon light 140 passes through the second refractive surface 135 beyond which where the user places his or her pupil 150 to view the image;
• whereupon light 198 from the real-world scene passes through the compensation lens 160 and the waveguide 100 before reaching the pupil 150, where the see-through field of view of the real-world scene is up to 90° in the temple direction, up to 60° in the nasal direction, and up to 60° above and below a straight-ahead view.