Patent ID: 8878780

Claim:
A display apparatus suitable for viewing by a user, the display apparatus comprising: at least an image generator displaying at least an image; a projection lens set located between the image generator and the user, the image projected by the projection lens set and generating a floating real image between the projection lens set and the user, wherein each beam forming the floating real image has a light-cone angle θ, each beam has a chief ray and a plurality of marginal rays, each marginal ray and the corresponding chief ray has an included angle α, and the light-cone angle θ=2α; a depth detecting module detecting the position of the user, the image generator and the projection lens set adjusting the position of the floating real image according to the position of the user, wherein the size of the floating real image is L, the distance between two eyes of the user is W, the distance between the user and the floating real image is D, and the light-cone angle θ satisfies a formula: θ ≥ tan - 1 ⁡ ( L + W D ) ; and a control unit electrically connected to the image generator, the projection lens set, and the depth detecting module.