An optical apparatus includes a touch substrate; a waveguide layer arranged on the touch substrate, the waveguide layer including a plurality of waveguides; an optical output structure arranged on the waveguide layer and configured to output light propagating in the plurality of waveguides at touched locations on the touch substrate; a gap layer arranged to provide a predetermined gap between the waveguide layer and the optical output structure; and an optical system, which projects light output by the optical output structure.