Optics: image projectors – Prism in light path
Reexamination Certificate
2007-04-24
2010-02-23
Lee, Diane I (Department: 2851)
Optics: image projectors
Prism in light path
C353S033000, C359S490020, C359S638000, C349S030000, C348S771000
Reexamination Certificate
active
07665850
ABSTRACT:
Prism elements having TIR surfaces placed in close proximity to the active area of a SLM device to separate unwanted off-state and/or flat-state light from the projection ON-light bundle. The TIR critical angle of these prisms is selected to affect either the off-state light or additionally, any portion of flat-state light reflected from the SLM. These TIR surfaces are placed to immediately reflect the unwanted light as it comes off the SLM, thereby preventing the contamination of light along the projection path, which tends to degrade the system contrast. To further improve the optical performance of the system, these TIR prisms can be attached directly to the SLM package, completely eliminating the package window. Also, these TIR prism can be coupled to DMDs having asymmetric mirrors, which tilt through a larger angle for the ON-light to provide high etendue and lumen output, but through near-zero degrees for the OFF-light, thereby improving the separation of any unwanted light from the off/flat states.
REFERENCES:
patent: 6144498 (2000-11-01), Bryars et al.
patent: 6249387 (2001-06-01), Poradish et al.
patent: 6250763 (2001-06-01), Fielding et al.
patent: 6461000 (2002-10-01), Magarill
patent: 6644813 (2003-11-01), Bowron
patent: 6663243 (2003-12-01), Fielding et al.
patent: 6873450 (2005-03-01), Patel et al.
Brady III Wade James
Brill Charles A.
Crud Magda
Lee Diane I
Telecky , Jr. Frederick J.
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