Optics: image projectors – Light shield – mask – hood – or diaphragm
Reexamination Certificate
2007-02-27
2007-02-27
Perkey, W. B. (Department: 2851)
Optics: image projectors
Light shield, mask, hood, or diaphragm
C353S001000, C359S740000, C359S649000
Reexamination Certificate
active
10662268
ABSTRACT:
A method and system for improving the contrast ratio of a projected image. An asymmetric aperture stop improves the contrast ratio of a projected image. Using slightly offset projection, the majority of the on-state projection light from the modulator array passes through a region that is not centered in the projection lens pupil. The blocked region of the asymmetric aperture is oriented toward the illumination path and away from the specular reflection path. The asymmetric aperture is able to block a significant portion of the diffracted light using the blocked region, without blocking much of the desired projection light passing through the remainder of the aperture. The result is that dark regions of the image become significantly darker, while light regions remain about the same. The same effect occurs without offset illumination.
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Dewald D. Scott
Penn Steven M.
Segler, Jr. Dana J.
Brady III Wade James
Brill Charles A.
Cruz Magda
Perkey W. B.
Telecky , Jr. Frederick J.
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