Controllable illumination device
The invention relates to a controllable illumination device for an autostereoscopic or holographic display, which illumination device contains an illumination matrix of primary light sources having at least one luminous element per light source and a controllable light modulator (SLM) and a reproduction matrix. A computer-generated hologram (CGH) illuminated by the primary light sources ( 11, . . . , 1 n ) is coded on the controllable light modulator (SLM) and generates, in at least one plane downstream of the SLM, a matrix—reconstructed from the computer-generated hologram (CGH)—of secondary light sources ( 2 ) having a secondary light distribution for the purpose of illuminating the reproduction matrix ( 4 ) and for the purpose of focussing in light bundles onto each eye of the viewer via an imaging matrix. The CGH is calculated and reconstructed on the basis of the number of and the positions of the viewers and the system parameters. Owing to the reconstruction of the secondary light sources in a plurality of planes, it is possible for the image information of the display to be tracked for the viewers not only in the case of lateral movements but also in the axial direction.
1. Controllable illumination device comprising an illumination matrix of primary light sources with at least one light-emitting element per light source and a controllable light modulator, the light of which penetrates a reproduction matrix comprising image information and is directed in bundles from an imaging matrix onto each eye of a viewer in a viewing plane, the imaging matrix comprising at least one imaging element; and a computer-generated hologram being encoded in the controllable light modulator and illuminated by primary light sources, whereby
the encoding is performed using variable parameters in order to realize an illumination configurable depending on the position of the viewer's eyes, and in at least one plane following the controllable light modulator a matrix of secondary light sources with a secondary light distribution is reconstructed by the computer-generated hologram.
2. Controllable illumination device according to claim 1 , wherein the reproduction matrix is a stereoscopic or holographic display.
3. Controllable illumination device according to claim 1 , wherein the secondary light sources form a matrix which optionally comprises point shaped light elements, line shaped light elements or area shaped light elements with a secondary light distribution.
4. Controllable illumination device according to claim 1 , wherein the secondary light distribution is modified by changing the matrix of primary light sources and/or by changing the encoding of the computer-generated hologram.
5. Controllable illumination device according to claim 1 , wherein the secondary light distribution is variable as regards the number of secondary light sources and the distances among the individual secondary light sources.
6. Controllable illumination device according to claim 1 , wherein the secondary light sources can be moved in lateral, but also in axial direction.
7. Controllable illumination device according to claim 1 , wherein the controllable light modulator for hologram encoding is a transmissive or a reflective element.
8. Controllable illumination device according to claim 1 , wherein the controllable light modulator is preceded or followed by further optical elements for shaping, deflecting or eliminating bundles of rays, whereby an additional optical element can be a phase mask when a amplitude-modulating CGH is used.
9. Controllable illumination device according to claim 1 , wherein the controllable light modulator with encoded computer-generated hologram (CGH) is followed by another transmissive controllable light modulator with variable openings to eliminate diffused light and light of higher diffraction orders, and to limit the extension of the secondary light sources.
10. Controllable illumination device according to claim 1 , wherein the secondary light distributions corresponding with a multitude of viewers' eye positions and the individual computer-generated holograms (CGH) are pre-calculated and stored in a look-up table.
11. Controllable illumination device according to claim 2 with a holographic display as the reproduction matrix, wherein the primary and secondary light sources used to reconstruct the hologram of the reproduction matrix exhibit sufficient spatial and temporal coherence.