Corrective optics for reducing fixed pattern noise in head mounted displays
An electronic display assembly includes a display element and a corrective element coupled to the display element. The display element has a first plurality of sub-pixels of a first type and a second plurality of sub-pixels of a second type. Two adjacent sub-pixels of the first plurality of sub-pixel are separated by a sub-pixel distance. The corrective element has a plurality of features configured to diffuse light emitted by the first plurality of sub-pixels such that an apparent distance between the two adjacent sub-pixels of the first type, viewed at a viewing distance away from the electronic display assembly, is less than the sub-pixel distance.
1. An electronic display assembly comprising:
a display element having a first plurality of sub-pixels of a first type and a second plurality of sub-pixels of a second type, wherein two adjacent sub-pixels of the first plurality of sub-pixel are separated by a sub-pixel distance; and
a corrective element coupled to the display assembly, the corrective element having a plurality of stepped pillars configured to diffuse light emitted by the first plurality of sub-pixels such that an apparent distance between the two adjacent sub-pixels of the first type, viewed at a viewing distance away from the electronic display assembly, is less than the sub-pixel distance, wherein a pitch between adjacent stepped pillars of the plurality of stepped pillars satisfies the following equation:
d f =3λ D/d p ,
wherein d f represents the pitch between the adjacent stepped pillars, λ represents a wavelength of light emitted by the first plurality of sub-pixels, D represents the viewing distance, and d p represents the sub-pixel distance.
2. The electronic display assembly of claim 1 , wherein the corrective element includes features selected from a group consisting of: holes and stepped holes.
3. The electronic display element of claim 1 , wherein the stepped pillars are arranged in a square grid.
4. The electronic display element of claim 1 , wherein the stepped pillars are arranged in a hexagonal grid.
5. The electronic display assembly of claim 1 , wherein a pitch between adjacent stepped pillars of the corrective element is less than the sub-pixel distance.
6. The electronic display assembly of claim 1 , wherein a portion of the sub-pixel distance is dark space, and the plurality of stepped pillars are configured to correct for fixed pattern noise by blurring an image of each the two adjacent sub-pixels to mask the dark space between the two adjacent sub-pixels.
7. The electronic display assembly of claim 1 , wherein the plurality of stepped pillars are configured to blur images of each the two adjacent sub-pixels by causing light emitted by each sub-pixel to appear as a plurality of closely spaced sub-pixels at the viewing distance.
8. The electronic display assembly of claim 1 , wherein the first plurality of sub-pixels are configured to emit light at a first wavelength, and the second plurality of sub-pixels are configured to emit light at a second wavelength.
9. The electronic display assembly of claim 8 , wherein the corrective element is configured to selectively diffuse light emitted by the first plurality of sub-pixels and to not diffuse light emitted by the second plurality of sub-pixels.
10. The electronic display assembly of claim 8 , wherein the corrective element is configured to diffuse light emitted by the first plurality of sub-pixels by a greater amount than the light emitted by the second plurality of sub-pixels.
11. The electronic display assembly of claim 1 , wherein the corrective element comprises a surface of the display element, and the stepped pillars are etched onto the surface of the display element using a single step process.
12. The electronic display assembly of claim 11 , wherein the stepped pillars are etched onto the surface of the display element using a nanoimprint lithography process.
13. The electronic display assembly of claim 1 , wherein the display element is a screen of a mobile device, and the corrective element is a film applied to a mobile device to reduce the appearance of defects on the screen.
14. An electronic display assembly comprising:
a display element having a plurality of sub-pixels, wherein two sub-pixels of the plurality of sub-pixels are separated by a sub-pixel distance; and
a corrective element coupled to the display assembly, the corrective element having a plurality of stepped pillars configured to diffuse light emitted by the plurality of sub-pixels such that an apparent distance between the two adjacent sub-pixels, viewed at a viewing distance away from the electronic display assembly, is less than the sub-pixel distance, wherein a pitch between adjacent stepped pillars of the plurality of stepped pillars satisfies the following equation:
d f =3λ D/d p ,
wherein d f represents the pitch between the adjacent stepped pillars, λ represents a wavelength of light emitted by the first plurality of sub-pixels, D represents the viewing distance, and d p represents the sub-pixel distance.
15. The electronic display assembly of claim 14 , wherein the corrective element includes features selected from a group consisting of: one of holes and stepped holes, and the features are arranged in one of a square grid or a hexagonal grid.
16. The electronic display assembly of claim 14 , wherein a pitch between adjacent stepped pillars of the corrective element is less than the sub-pixel distance.
17. The electronic display assembly of claim 14 , wherein a portion of the sub-pixel distance is dark space, and the plurality of stepped pillars are configured to correct for fixed pattern noise by blurring an image of each the two adjacent sub-pixels to mask the dark space between the two adjacent sub-pixels.
18. The electronic display assembly of claim 14 , wherein the plurality of stepped pillars are configured to blur images of each the two adjacent sub-pixels by causing light emitted by each sub-pixel to appear as a plurality of closely spaced sub-pixels at the viewing distance.
19. The electronic display assembly of claim 14 , wherein the corrective element comprises a surface of the display element, and the stepped pillars are etched onto the surface of the display element using a single step nanoprint lithography process.