Manufacturing for virtual and augmented reality systems and components
Disclosed is an improved diffraction structure for 3D display systems. The improved diffraction structure includes an intermediate layer that resides between a waveguide substrate and a top grating surface. The top grating surface comprises a first material that corresponds to a first refractive index value, the underlayer comprises a second material that corresponds to a second refractive index value, and the substrate comprises a third material that corresponds to a third refractive index value. According to additional embodiments, improved approaches are provided to implement deposition of imprint materials onto a substrate, which allow for very precise distribution and deposition of different imprint patterns onto any number of substrate surfaces.
1. A diffractive optical element, comprising:
a first substrate, the first substrate having a first region and a second region; and
a first layer disposed on the first substrate, the first layer having
a first diffractive optical element having a first depth and disposed on the first region of the first substrate, and
a second diffractive optical element having a second depth and disposed on the second region of the first substrate,
wherein the first depth is different from the second depth.
2. The diffractive optical element of claim 1 ,
wherein the first diffractive optical element has a first optical index, and
wherein the second diffractive optical element has a second optical index different from the first optical index.
3. The diffractive optical element of claim 1 ,
wherein the first diffractive optical element has a first diffraction pattern, and
wherein the second diffractive optical element has a second diffraction pattern different from the first diffraction pattern.
4. The diffractive optical element of claim 1 ,
wherein the first diffractive optical element has a first optical function, and
wherein the second diffractive optical element has a second optical function.
5. The diffractive optional element of claim 4 ,
wherein the first optical function is in-coupling, and
wherein the second optical function is orthogonal pupil expansion or exit pupil expansion.
6. The diffractive optical element of claim 1 ,
wherein the first diffractive optical element is an in-coupling grating, and
wherein the second diffractive optical element is an orthogonal pupil expander or an exit pupil expander.
7. The diffractive optical element of claim 1 ,
wherein the first diffractive optical element has a first refractive index, and
wherein the second diffractive optical element has a second refractive index different from the first refractive index.
8. The diffractive optical element of claim 7 ,
wherein the first substrate has a substrate refractive index,
wherein the first refractive index value is smaller than the second refractive index value and the substrate refractive index value of the first substrate, and
wherein the substrate refractive index value is smaller than the second refractive index value.
9. The diffractive optical element of claim 1 , further comprising a second layer disposed above the first layer,
wherein the second layer comprises
a first region includes a first material having a first refractive index, and
a second region includes a first material having a second refractive index,
wherein the first substrate includes a third material having a third refractive index, and
wherein the first, second, and third refractive index values are selected based at least in part upon a first requirement for a diffraction efficiency or a second requirement for a field of view provided by the diffractive optical element.
10. An eyepiece, comprising the diffractive optical element of claim 1 .
11. The eyepiece of claim 10 , further comprising:
a first lens stacked on top of the diffractive optical element; and
a second diffractive optical element stacked on top of the first lens,
wherein the diffractive optical element is closer to a viewer's eye than the second diffractive optical element.
12. The eyepiece of claim 11 ,
wherein the diffractive optical element defines a first focal plane with a first focal distance,
wherein the second diffractive element comprises a second substrate and defines a second focal plane with a second focal distance that is smaller than the first focal distance, and
wherein the second diffractive element is separated from the first diffractive element by the first lens.
13. The eyepiece of claim 12 , further comprising:
a second lens stacked on top of the second diffractive optical element; and
a third diffractive optical element stacked on top of the second lens,
wherein the third diffractive optical element is disposed farther away from the viewer's eye than the second diffractive optical element.
14. The eyepiece of claim 13 , wherein the third diffractive optical element defines a third focal plane with a third focal distance that is smaller than the second focal distance.
15. The eyepiece of claim 13 , further comprising a compensation lens stacked on top of the third diffractive optical element,
wherein the compensation lens is selected based at least in part upon an aggregate power of the first and the second lens.
16. The eyepiece of claim 13 , further comprising:
an additional lens stacked on top of the third diffractive optical element; and
one or more additional diffractive optical elements stacked on top of the additional lens.
17. The eyepiece of claim 16 , further comprising a compensation lens stacked on top of the one or more additional diffractive optical elements,
wherein the compensation lens is selected based at least in part upon an aggregate power of lenses separating diffractive optical layers in the eyepiece.
18. The eyepiece of claim 13 , wherein at least two of the diffractive optical element, the second diffractive optical element, and the third diffractive optical element are multiplexed to create at least one additional focal plane in addition to the first focal plane, the second focal plane, and the third focal plane.
19. The eyepiece of claim 10 , further comprising:
a second layer disposed an opposite surface opposing a surface onto which the first layer is deposited,
wherein the second layer comprises
a first region includes a first material having a first refractive index, and
a second region includes a first material having a second refractive index.
20. The eyepiece of claim 12 ,
wherein the first substrate has a first imprinted pattern; and
wherein the second substrate has a second imprinted pattern.