Optical combiner lens with spacers between lens and lightguide
An optical combiner lens includes a lens and a lightguide with a gap defined between the lens and the lightguide. Spacers are disposed in the gap to maintain the gap at a set height. A method of making the optical combiner lens and a wearable heads-up display including the optical combiner lens are disclosed.
1. An optical combiner lens, comprising:
a lens having an outer lens surface and an inner lens surface;
a lightguide in a stack with the lens, the lightguide having a top lightguide surface and a bottom lightguide surface, the top lightguide surface in opposing relation to the inner lens surface with a gap defined between the top lightguide surface and the inner lens surface; and
a plurality of spacers, independent from the inner lens surface and lightguide, disposed in the gap to maintain the gap at a set height, wherein the plurality of spacers are distributed across the center of the top lightguide surface to maintain the gap at a set height.
2. The optical combiner lens of claim 1 , wherein the set height of the gap is in a range from 2 microns to 100 microns.
3. The optical combiner lens of claim 1 , wherein the spacers are microbeads.
4. The optical combiner lens of claim 1 , wherein the spacers are micropillars.
5. The optical combiner lens of claim 1 , wherein the spacers comprise silica.
6. The optical combiner lens of claim 1 , wherein the spacers comprising a plastic material.
7. The optical combiner lens of claim 1 , wherein the gap contains a medium in spaces between and around the spacers, the medium having a refractive index that is lower than a refractive index of the lightguide.
8. The optical combiner lens of claim 1 , wherein a concentration of the spacers on the top lightguide surface is in a range from 1 to 100 spacers per mm2.
9. The optical combiner lens of claim 1 , wherein the distribution of the spacers across the top lightguide surface is nonuniform.
10. The optical combiner lens of claim 9 , wherein the lightguide has an input zone at which light enters the lightguide, an output zone from which light exits the lightguide, and a propagation zone between the input zone and the output zone that provides a propagation path for light from the input zone to the output zone;
wherein the top lightguide surface has a first area coinciding with at least one of the input zone, the output zone, and the propagation zone of the lightguide and a second area outside of the first area; and
wherein a concentration of the spacers on the first area is lower than a concentration of the spacers on the second area.
11. The optical combiner lens of claim 10 , wherein the concentration of the spacers in the first area is zero.
12. The optical combiner lens of claim 1 , further comprising an adhesive layer applied to at least one of the inner lens surface and the top lightguide surface, wherein at least some of the spacers contact the adhesive layer and are retained in place in the gap by the adhesive layer.
13. The optical combiner lens of claim 1 , further comprising a deformable layer formed on the top lightguide surface, wherein at least some of the spacers are pressed into the deformable layer and retained in place in the gap by the deformable layer.
14. The optical combiner lens of claim 1 , further comprising an output coupler positioned to couple light out of the lightguide and an input coupler positioned to couple light into the lightguide.
15. The optical combiner lens of claim 1 , wherein the lens is a planoconvex lens or a meniscus lens, and wherein the lightguide is a planar lightguide.
16. The optical combiner lens of claim 1 , further comprising a seal engaging the lens and the lightguide and circumscribing the gap, wherein the lightguide has a side edge extending from a perimeter of the top lightguide surface to a perimeter of the bottom lightguide surface, wherein at least a portion of the seal wraps around at least a portion of the side edge of the lightguide, and wherein the at least a portion of the seal comprises nanoparticles that absorb and/or scatter light.
17. The optical combiner lens of claim 1 , further comprising a seal engaging the lens and the lightguide and circumscribing the gap, wherein the lightguide has a side edge extending from a perimeter of the top lightguide surface to a perimeter of the bottom lightguide surface, wherein at least a portion of the seal wraps around at least a portion of the side edge of the lightguide, and wherein the at least a portion of the side edge has an edge treatment selected from a shaped edge, a coated edge, a roughened edge, a polished edge, and an etched edge.