Directional polarization preserving screen
A directional polarization preserving front projection screen may be preferably produced using an engineered surface. Unlike statistical surfaces, engineered surfaces may provide locally specular reflections, with little to no bulk scatter, while substantially eliminating features smaller than a wavelength of illumination and thus true depolarization. Most, if not all, contours contributing to the slope probability density can be engineered to achieve a desired macroscopic gain profile. The screen may diffuse light by using locally specular reflections, in which a bias angle introduced to the gain profile of the screen may be determined by the slope of the ramps, and with resets that may be substantially hidden from projector illumination.
1 . A directional polarization preserving screen, comprising:
a substrate; and
a periodic diffuser structure disposed on the substrate, the periodic structure comprising:
a plurality of illuminated facets and a plurality of occluded facets, wherein the illuminated and the occluded facets are connected to and alternate with one another respectively, further wherein the illuminated facets substantially direct light to a predetermined area.
2 . The directional polarization preserving screen of claim 1 , further wherein the periodic diffuser structure allows incident light to undergo locally specular reflections.
3 . The directional polarization preserving screen of claim 1 , wherein the plurality of occluded facets are substantially hidden from projector illumination.
4 . The directional polarization preserving screen of claim 1 , wherein the plurality of illuminated facets further comprise features smaller than a wavelength of illumination.
5 . The directional polarization preserving screen of claim 1 , wherein the plurality of illuminated facets are smaller than the resolvable area on the substrate.
6 . The directional polarization preserving screen of claim 1 , wherein the illuminated facets are smaller than approximately 600 microns.
7 . The directional polarization preserving screen of claim 1 , wherein the illuminated facets are smaller than the pixel size of a projector.
8 . The directional polarization preserving screen of claim 1 , wherein the plurality of illuminated facets and the plurality of occluded facets comprise continuous horizontal facets.
9 . The directional polarization preserving screen of claim 1 , wherein the plurality of illuminated facets have a variable slope.
10 . The directional polarization preserving screen of claim 9 , wherein the variable slope of the plurality of illuminated facets change vertically.
11 . The directional polarization preserving screen of claim 9 , wherein the slope of the plurality of illuminated facets approximate an elliptical surface.
12 . The directional polarization preserving screen of claim 1 , wherein the plurality of illuminated and occluded facets are coated with an engineered polarization preserving pigment.
13 . A method for directing projection light, comprising:
allowing projection light to reflect off of a plurality of illuminated facets disposed on a projection screen; and
substantially preventing projection light from reflecting off of a plurality of occluded facets disposed on the projection screen, wherein the illuminated and occluded facets connect to and alternate with one another, respectively.
14 . The method for directing projection light of claim 13 , further comprising primarily determining the bias angle from the slope of the illuminated facets.
15 . The method for directing projection light of claim 13 , further comprising allowing ambient light to be steered away from a predetermined area.
16 . The method for directing projection light of claim 14 , wherein allowing projection light to reflect off of a plurality of illuminated facets disposed on a projection screen further comprises, allowing the projection light to be directed to a predetermined area.
17 . The method for directing projection light of claim 16 , further comprising allowing incident light to undergo locally specular reflections.
18 . The method for directing projection light of claim 13 , wherein the plurality of illuminated facets and the plurality of occluded facets comprise continuous horizontal facets.
19 . The method for directing projection light of claim 13 , further comprising varying the slope of the illuminated facets.
20 . The method for directing projection light of claim 19 , wherein the slope of the plurality of illuminated facets varies vertically.
21 . The method for directing projection light of claim 13 , further comprising approximating an elliptical surface with the slope of the plurality of illuminated facets.
22 . The method for directing projection light of claim 13 , further comprising coating the plurality of illuminated and occluded facets with an engineered polarization preserving pigment.