Eyepiece for head-mounted display and method for making the same
A method, includes providing a wafer including a first surface grating extending over a first area of a surface of the wafer and a second surface grating extending over a second area of the surface of the wafer; de-functionalizing a portion of the surface grating in at least one of the first surface grating area and the second surface grating area; and singulating an eyepiece from the wafer, the eyepiece including a portion of the first surface grating area and a portion of the second surface grating area. The first surface grating in the eyepiece corresponds to an input coupling grating for a head-mounted display and the second surface grating corresponds to a pupil expander grating for the head-mounted display.
1. A method, comprising:
providing a wafer comprising a first plurality of surface gratings extending over a first area of a surface of the wafer and a second plurality of surface gratings extending over a second area of the surface of the wafer, the first and second areas being spaced apart;
de-functionalizing a portion of at least two of the first plurality of surface gratings in a first surface grating area or the second plurality of surface gratings in a second surface grating area; and
singulating at least two eyepieces, each eyepiece incorporating a part of the wafer comprising a pair of surface gratings, each pair including a defunctionalized grating from the first or second surface gratings and a corresponding one of the remaining first or second surface gratings, wherein a distance between the defunctionalized grating and the one of the remaining first or second of surface gratings is different for each eyepiece.
2. The method of claim 1 , wherein de-functionalizing the portion of at least two of the first plurality of surface gratings in the first surface grating area or second plurality of surface gratings in the second surface grating area comprises planarizing the portion of the corresponding surface grating.
3. The method of claim 2 , wherein planarizing the portion of at least two of the first plurality of surface gratings in the first surface grating area or second plurality of surface gratings in the second surface grating area comprises casting a material over the corresponding portion of the surface grating.
4. The method of claim 3 , wherein the material being cast is the same material as the material forming the surface grating.
5. The method of claim 3 , wherein the material is a polymer material.
6. The method of claim 2 , wherein the first plurality of surface gratings or the second plurality of surface gratings comprise multiple grating heights above the surface of the wafer following de-functionalizing.
7. The method of claim 1 , further comprising depositing a reflective material on a portion of one of the first plurality of surface gratings.
8. The method of claim 7 , wherein the reflective material is a metal.
9. The method of claim 1 , wherein the de-functionalized portion of the first surface grating area or second surface grating areas have a height above the surface that is greater than a height of the first surface grating or second surface grating.
10. The method of claim 9 , wherein the height of the de-functionalized portion is no more than 100 nm greater than the height of the corresponding surface grating.
11. The method of claim 1 , wherein providing the wafer comprises imprinting the first plurality and second plurality of gratings onto the surface of the wafer.
12. The method of claim 1 , wherein providing the wafer comprises a casting a wafer with the first plurality and second plurality of gratings.
13. The method of claim 1 , wherein the second area has a minimum lateral dimension of more than 30 mm.
14. The method of claim 1 , wherein the second plurality of surface gratings has a maximum lateral dimension of 30 mm or less.
15. The method of claim 1 , wherein the first plurality of surface gratings has a maximum lateral dimension of 5 mm or less.
16. A wafer, comprising:
a first plurality of surface gratings extending over a first area of a surface of the wafer and a second plurality of surface gratings extending over a second area of the surface of the wafer, the first and second areas being spaced apart, wherein at least two of the first plurality or the second plurality of surface gratings include a surrounding de-functionalized portion, and
wherein each surface grating of the first plurality or the second plurality of surface gratings is spaced part from a corresponding one of the first plurality or the second plurality of surface gratings by a distance which is different for each pair of corresponding surface gratings.
17. The wafer of claim 16 , wherein the first plurality of surface gratings or the second plurality of surface gratings comprise multiple grating heights above the surface of the wafer in the de-functionalized portion.
18. The wafer of claim 16 , wherein the de-functionalized portion has a height above the surface that is greater than a height of the first plurality or the second plurality of surface gratings.
19. The wafer of claim 16 , wherein a portion of the first plurality of surface gratings includes a reflective material.
20. The wafer of claim 16 , wherein de-functionalized portion comprises a planarized portion of the corresponding surface grating.