An image generation device having: a spatial light modulator; a source of light; a beam deflector; an illumination waveguide and an image transport waveguide, each waveguide containing at least one switchable grating; and a coupler for directing scanned light into a first set of TIR paths in said illumination waveguide. A switchable grating in the illumination waveguide diffracts light onto the SLM, a switchable grating in the image transport waveguide diffracting image-modulated from the SLM into a waveguide path.