An image projector with a high optical efficiency projects an image at an arbitrary distance from an observer. The image projector includes an illumination module having at least one spatially coherent light source; a phase image generator with an array of optical phase shifting elements; an electronic image controller connected electrically to the phase image generator; and a waveguide which includes at least one embedded partial reflector. The waveguide may be positioned either between the illumination module and the waveguide, or between the waveguide and the observer. The phase image generator may include phase shifts for canceling speckle, correcting optical aberrations, and/or compensating interference caused by light rays having different optical path lengths.