Spatial light modulator with integrated optical compensation structure
View Patent ↗A spatial light modulator comprises an integrated optical compensation structure, e.g., an optical compensation structure arranged between a substrate and a plurality of individually addressable light-modulating elements, or an optical compensation structure located on the opposite side of the light-modulating elements from the substrate. The individually addressable light-modulating elements are configured to modulate light transmitted through or reflected from the transparent substrate. Methods for making such spatial light modulators involve fabricating an optical compensation structure over a substrate and fabricating a plurality of individually addressable light-modulating elements over the optical compensation structure. The optical compensation structure may be a passive optical compensation structure. The optical compensation structure may include one or more of a supplemental frontlighting source, a diffuser, a black mask, a diffractive optical element, a color filter, an anti-reflective layer, a structure that scatters light, a microlens array, and a holographic film.
1. A spatial light modulator comprising:
a substrate;
a plurality of light-modulating elements over the substrate, the light-modulating elements configured to interferometrically modulate light transmitted through the substrate;
a first optical compensation structure under the substrate;
a second optical compensation structure between the substrate and the light-modulating elements, at least a portion of the second optical compensation structure, facing the plurality of light-modulating elements, being non-planar; and
a planarization layer between the second optical compensation structure and the plurality of light-modulating elements, the planarization layer contacting the non-planar portion of the second optical compensation structure.
2. The spatial light modulator of claim 1 , wherein the substrate is transparent to light.
3. The spatial light modulator of claim 1 , wherein the first optical compensation structure comprises a diffuser.
4. The spatial light modulator of claim 1 , wherein the second optical compensation structure comprises a plurality of scattering elements.
5. The spatial light modulator of claim 1 , wherein the second optical compensation structure comprises a microlens array.
6. The spatial light modulator of claim 1 , wherein the second optical compensation structure comprises a diffractive optical element.
7. The spatial light modulator of claim 1 , wherein the second optical compensation structure comprises a scattering element.
8. The spatial light modulator of claim 1 , wherein the first optical compensation structure is a passive optical compensation structure.
9. The spatial light modulator of claim 1 , wherein the second optical compensation structure is a passive optical compensation structure.
10. The spatial light modulator of claim 1 , wherein the second optical compensation structure comprises one or more of the group consisting of a plurality of scattering elements, a microlens array, a diffuser, a black mask, and a diffractive optical element.
11. The spatial light modulator of claim 10 , wherein the first optical compensation structure comprises one or more of the group consisting of a diffuser, a color filter, a black mask, a plurality of scattering elements, a microlens array, a holographic film, and a diffractive optical element.
12. The spatial light modulator of claim 1 , wherein the light-modulating elements each comprise a cavity and a movable wall comprising a reflective metal.
13. The spatial light modulator of claim 1 , wherein the first optical compensation structure is configured to have a different optical effect than the second optical compensation structure.
14. The spatial light modulator of claim 1 , wherein the first optical compensation structure is substantially non-planar.
15. The spatial light modulator of claim 1 , wherein the second optical compensation structure is between the light-modulating elements and a viewer of the spatial light modulator.
16. The spatial light modulator of claim 1 , wherein the second optical compensation structure is between the light-modulating elements and a front surface of the spatial light modulator.
17. The spatial light modulator of claim 1 , wherein the planarization layer forms a support layer for subsequent fabrication steps.
18. The spatial light modulator of claim 1 , wherein the planarization layer is fabricated on the second optical compensation structure by a thin film deposition process.
19. A spatial light modulator comprising:
a substrate;
a plurality of light-modulating elements over the substrate, the light-modulating elements configured to interferometrically modulate light transmitted through the substrate;
a first optical compensation structure under the substrate;
a second optical compensation structure having a non-planar portion and arranged between the substrate and the light-modulating elements, wherein the second optical compensation structure comprises one or more of the group consisting of a plurality of scattering elements, a microlens array, a diffuser, and a diffractive optical element; and
a planarization layer between the second optical compensation structure and the plurality of light-modulating elements, the planarization layer in contact with the non-planar portion of the second optical compensation structure.
20. The spatial light modulator of claim 19 , wherein the second optical compensation structure is between the light-modulating elements and a viewer of the spatial light modulator.
21. The spatial light modulator of claim 19 , wherein the second optical compensation structure is between the light-modulating elements and a front surface of the spatial light modulator.
22. The spatial light modulator of claim 19 , wherein the light-modulating elements each comprise a cavity and a movable wall comprising a reflective metal.
23. The spatial light modulator of claim 19 , wherein the planarization layer forms a support layer for subsequent fabrication steps.
24. The spatial light modulator of claim 19 , wherein the planarization layer is fabricated on the second optical compensation structure by a thin film deposition process.
25. The spatial light modulator of claim 19 , wherein the second optical compensation structure comprises a plurality of scattering elements.
26. The spatial light modulator of claim 19 , wherein the second optical compensation structure comprises a microlens array.
27. The spatial light modulator of claim 19 , wherein the second optical compensation structure comprises a diffuser.
28. The spatial light modulator of claim 19 , wherein the second optical compensation structure comprises a diffractive optical element.
29. A spatial light modulator comprising:
a substrate;
a plurality of light-modulating elements over the substrate, the light-modulating elements configured to interferometrically modulate light transmitted through the substrate;
a first optical compensation structure under the substrate;
a second optical compensation structure arranged between the substrate and the light-modulating elements, wherein the first optical compensation structure is configured to achieve a different optical effect than the second optical compensation structure; and
a planarization layer between the second optical compensation structure and the plurality of light-modulating elements, the planarization layer in contact with a non-planar portion of the second optical compensation structure.
30. The spatial light modulator of claim 29 , wherein the second optical compensation structure is between the light-modulating elements and a viewer of the spatial light modulator.
31. The spatial light modulator of claim 29 , wherein the second optical compensation structure is between the light-modulating elements and a front surface of the spatial light modulator.
32. The spatial light modulator of claim 29 , wherein the light-modulating elements each comprise a cavity and a movable wall comprising a reflective metal.
33. The spatial light modulator of claim 29 , wherein the planarization layer forms a support layer for subsequent fabrication steps.
34. The spatial light modulator of claim 29 , wherein the planarization layer is fabricated on the second optical compensation structure by a thin film deposition process.