Color combiner for solid-state light sources

Abstract

An illumination apparatus has first and second optical condenser systems sharing a common aperture. The first optical condenser system has a first solid-state light source having a first spectral band and a first curved surface spaced apart from the first solid-state light source and treated to reflect the first spectral band along a first optical path to exit at the common aperture and to pass light outside the first spectral band. The second optical condenser system has a second solid-state light source having a second spectral band and a second curved surface disposed behind the first curved surface with respect to the first and second light sources and treated to reflect the second spectral band along a second optical path to exit at the common aperture.

1 . A display apparatus comprising:
 a) an illumination apparatus comprising at least first and second optical condenser systems sharing a common aperture, the first optical condenser system comprising:
 a first solid-state light source having a first spectral band; 
 a first curved surface spaced apart from the first solid-state light source and treated to reflect the first spectral band along a first optical path to exit at the common aperture and to pass light outside the first spectral band; 
   and the second optical condenser system comprising:
 a second solid-state light source having a second spectral band; 
   a second curved surface disposed behind the first curved surface with respect to the first and second light sources and treated to reflect the second spectral band along a second optical path to exit at the common aperture;   b) a light homogenizer disposed near the common aperture for uniformizing illumination from the illumination apparatus;   c) a spatial light modulator in the path of the uniformized illumination from the light homogenizer for providing modulated light; and   d) a projection lens disposed to project modulated light towards a display surface.   
   
   
       2 . The display apparatus of  claim 1  wherein the illumination apparatus further comprises a third optical condenser system that comprises
 a third solid-state light source having a third spectral band; and   a third curved surface spaced apart from the third solid-state light source and treated to reflect the third spectral band along a first optical path to exit at the common aperture.   
   
   
       3 . The display apparatus of  claim 1  wherein the first and second solid-state light sources are taken from the group consisting of light-emitting diodes, organic light-emitting diodes, and polymer light-emitting diodes. 
   
   
       4 . The display apparatus of  claim 1  wherein the light homogenizer is taken from the group consisting of a lenslet array, a fly's-eye lenslet array, a light tunnel, an integrator bar, a mirror, one or more lenses, a compound parabolic concentrator, and a diffuser. 
   
   
       5 . The display apparatus of  claim 1  wherein the spatial light modulator is taken from the group consisting of a digital micromirror device and a liquid crystal display device. 
   
   
       6 . The display apparatus of  claim 1  wherein the common aperture lies in the plane containing the first and second solid-state light sources. 
   
   
       7 . The display apparatus of  claim 1  wherein at least one of the first and second curved surfaces is a dichroic surface. 
   
   
       8 . The display apparatus of  claim 1  wherein the first curved surface has a shape that is substantially spherical, ellipsoidal, or paraboloid. 
   
   
       9 . The display apparatus of  claim 1  wherein the first and second solid-state light sources are optically immersed in a dielectric. 
   
   
       10 . A display apparatus comprising:
 a) an illumination apparatus comprising at least:
 a first concave curved reflective surface having a first axis and a first vertex; 
 a second concave curved surface treated to reflect light of a first spectral band and to transmit other light and having a second axis and a second vertex, wherein the concavity of the second concave curved surface is opposed to the concavity of the first concave curved reflective surface and the second axis is non-collinear with the first axis; 
 a third concave curved surface behind the second concave curved surface with respect to the first concave curved reflective surface and treated to reflect light transmitted through the second concave curved surface, and further having a third axis non-collinear with the second axis and having a third vertex; 
 a first solid-state light source disposed near the first vertex and along the second axis; 
 a second solid-state light source disposed near the first vertex and along the third axis; and 
 an aperture extending through the second and third vertices; 
   b) a light homogenizer disposed near the aperture for uniformizing illumination from the illumination apparatus;   c) a spatial light modulator in the path of the uniformized illumination from the light homogenizer for providing modulated light; and   d) a projection lens disposed to project modulated light towards a display surface.   
   
   
       11 . A display apparatus comprising:
 a) an illumination apparatus comprising at least first and second optical condenser systems sharing a common aperture, the first optical condenser system comprising:
 a first solid-state light source having a first spectral band; 
 a first curved surface spaced apart from the first solid-state light source and treated to reflect the first spectral band along a first optical path to exit at the common aperture and to pass light outside the first spectral band; 
   and the second optical condenser system comprising:
 a second solid-state light source having a second spectral band; 
   a second curved surface disposed behind the first curved surface with respect to the first and second light sources and treated to reflect the second spectral band along a second optical path to exit at the common aperture;   b) a diffuser disposed to accept light collimated through a collimating lens from the common aperture;   c) a spatial light modulator in the path of illumination from the diffuser for providing modulated light; and   d) a projection lens disposed to project modulated light towards a display surface.