Patent ID: 7773293

Claim:
A laser projection system comprising a laser source, a wavelength conversion device, and beam projection optics, wherein: the wavelength conversion device comprises an input face, an output face, and a waveguide region extending from the input face to the output face; the waveguide region comprises an axial waveguide portion and a pair of lateral planar waveguide portions confined between a pair of cladding layers; the waveguide region is structured such that an optical signal propagating from the input face to the output face along the waveguide region will define relatively high intensity light propagating in the axial waveguide portion and will be subject to a degree of scattering to define relatively low intensity laterally distributed parasitic light propagating in the lateral planar waveguide portions; the effective index of refraction n EFF (A) in the axial waveguide portion of the waveguide region, and the effective index of refraction n EFF (B) in the lateral planar waveguide portions of the waveguide region are established such that the relatively low intensity laterally distributed parasitic light is characterized by a scattering angle θ that is at least as large as the beam divergence angle of the relatively high intensity light propagating in the axial waveguide portion; and the beam projection optics are structured to discriminate between the laterally distributed parasitic light and the relatively high intensity light by discriminating against light emitted from the output face of the wavelength conversion device at angles larger than the divergence of the relatively high intensity light.