TIR light valve
View Patent ↗A light valve that switches light does so by enabling and disabling total internal reflection (TIR) on a surface of the light valve. The disabling of the TIR is accomplished by putting another optical element in contact with the surface and then diffusing or changing the direction of the light. These valves may be used in an array for a projection system or one at a time. The mechanical mechanism to move the optical element is a simple in that it only moves the optical element a small distance to change the valve from an on position to an off position.
1. A light valve comprising:
a means for bending light, said means for bending light having an index of refraction much greater than an index of refraction of a surrounding area, so that light projected onto a first surface of said means for bending light is reflected off a second surface of said means for bending light,
a switching element comprising a reflecting surface, and
a means for moving said reflecting surface of said switching element relative to said second surface of said means for bending light; wherein
when said switching means is in an on position, light passing through said first surface of said means for bending light reflects off of said second surface of said means for bending light and passes through an output surface of said means for bending light in a direction not substantially parallel to a direction of said light passing through said first surface, and
when said switching means is in an off position, said reflecting surface is moved to a position in close proximity to said second surface of said means for bending light, so that light passing through said first surface of said means for bending light is not reflected off said second surface, but rather continues on to a surface of said switching means and is redirected through said switching means in a direction not substantially parallel to a direction of said light passing through said first surface of said means for bending light.
2. The light valve of claim 1 wherein:
said switching means is moved between said on position and said off position by an electrostatic force.
3. The light valve of claim 1 wherein:
light is reflected off a serrated surface of said switch element when said switch element is in said off position.
4. The light valve of claim 1 wherein:
light is absorbed by said switch element when said switch element is in said off position.
5. The light valve of claim 1 wherein:
light is diffused by said switch element when said switch element is in said off position.
6. The light valve of claim 1 wherein:
said switch element has a diffuse topography.
7. The light valve of claim 1 wherein:
said means for bending light is a prism.
8. A light valve comprising:
an array of functionally equivalent light valves, each said light valve comprising:
a means for bending light, said means for bending light having an index of refraction much greater than an index of refraction of a surrounding area, so that light projected onto a first surface of said means for bending light is reflected off a second surface of said means for bending light,
a switching element comprising a reflecting surface, and
a means for moving said reflecting surface of said switching element relative to said second surface of said means for bending light; wherein
when said switching means is in an on position, light passing through said first surface of said means for bending light reflects off of said second surface of said means for bending light and passes through an output surface of said means for bending light, and
when said switching means is in an off position, said reflecting surface is moved to a position in close proximity to said second surface of said means for bending light, so that light passing through said first surface of said means for bending light is not reflected off said second surface, but rather continues on to a surface of said switching means and is redirected through said switching means in a direction not substantially parallel to a direction of said light passing through said first surface of said means for bending light.
9. The light valve of claim 8 wherein:
at least one of said switching means is moved between said on position and said off position by an electrostatic force.
10. The light valve of claim 8 wherein:
light is reflected off a serrated surface of each said switch element when said switch array is in said off position.
11. The light valve of claim 8 wherein:
light is absorbed by said switch elements comprising said array when said switch array is in said off position.
12. The light valve of claim 8 wherein:
light is diffused by each said switch element when said switch array is in said off position.
13. The light valve of claim 8 wherein:
at least one of said switch elements has a diffuse topography.
14. The light valve of claim 8 wherein:
said means for bending light is a prism.