Display for augmented reality and virtual reality systems
A gradient refractive index (GRIN) lens includes a transparent central disk and transparent annular segments, including central annular segments and peripheral annular segments. The central disk and each annular segment has a continuous optical phase profile at a design wavelength along a radial direction extending outward from a center of the central disk. An optical phase discontinuity is present at the interface between the central disk and the innermost central annular segment and at the interface between each pair of adjacent annular segments. Radial widths of the central annular segments decrease with increasing distance away from the center of the central disk. The peripheral annular segments have optical phase profiles for the design wavelength that are linear or have maximum first derivatives that are constant or become smaller with increasing distance of the peripheral annular segments away from the center of the central disk.
1 . A refractive optical device comprising:
a gradient refractive index (GRIN) lens shaped as a disk and including a central disk and a plurality of annular segments including:
a plurality of central annular segments disposed around the central disk, and
a plurality of peripheral annular segments disposed around the plurality of central annular segments;
wherein:
the central disk and each annular segment is transparent at a design wavelength;
the central disk and each annular segment has a continuous optical phase profile at the design wavelength along a radial direction extending radially outward from a center of the central disk;
an optical phase discontinuity is present at the interface between the central disk and the innermost central annular segment and at the interface between each pair of adjacent annular segments;
radial widths of the central annular segments decrease with increasing distance away from the center of the central disk; and
the peripheral annular segments have optical phase profiles for the design wavelength with magnitudes of maximum first derivatives that are constant or become smaller with increasing distance of the peripheral annular segments away from the center of the central disk.
2 . The refractive optical device of claim 1 wherein each peripheral annular segment has a linear optical phase profile at the design wavelength.
3 . The refractive optical device of claim 1 wherein the central disk and each central annular segment has a parabolic optical phase profile at the design wavelength.
4 . The refractive optical device of claim 1 wherein the peripheral annular segments each have a fixed width W.
5 . The refractive optical device of claim 4 wherein the fixed width W of the peripheral annular segments is 0.8 mm or larger.
6 . The refractive optical device of claim 1 wherein the peripheral annular segments have optical phase profiles for the design wavelength with constant first derivatives.
7 . The refractive optical device of claim 1 further comprising:
light blocking material disposed over the interface between the central disk and the central annular segment adjacent the central disk and over the interface between each pair of adjacent annular segments, the light absorbing material effective to block light at the design wavelength.
8 . The refractive optical device of claim 7 wherein the GRIN lens is shaped as said disk having a thickness and the light blocking material disposed over each interface has a radial width of at least 1.5 times the thickness of the disk.
9 . The refractive optical device of claim 1 wherein the central disk and each annular segment of the GRIN lens comprises a liquid crystal material, the refractive optical device further comprising:
a pair of substrates confining the central disk and the plurality of annular segments; and
electrodes arranged to electrically bias the central disk and the plurality of annular segments;
wherein the GRIN lens and the electrodes form a variable power GRIN lens whose focus is electrically tunable using the electrodes.
10 . An augmented reality (AR) or virtual reality (VR) system including:
An AR or VR headset; and
a variable power left eye lens and a variable power right eye lens each comprising a refractive optical device as set forth in claim 9 , wherein the variable power left and right eye lenses are configured to provide accommodation for viewing of AR or VR content at different distances.
11 . A refractive optical device comprising:
a gradient refractive index (GRIN) lens shaped as a disk having a radius of at least 2.5 cm and including a central disk and a plurality of annular segments including:
a plurality of central annular segments disposed around the central disk, and
a plurality of peripheral annular segments disposed around the plurality of central annular segments;
wherein:
the central disk and each annular segment is transparent at a design wavelength;
the central disk and each annular segment has a continuous optical phase profile at the design wavelength along a radial direction extending radially outward from a center of the central disk;
an optical phase discontinuity is present at the interface between the central disk and the innermost central annular segment and at the interface between each pair of adjacent annular segments;
radial widths of the central annular segments decrease with increasing distance away from the center of the central disk; and
the peripheral annular segments have widths of at least 0.8 mm.
12 . The refractive optical device of claim 11 wherein each peripheral annular segment has a linear optical phase profile at the design wavelength.
13 . The refractive optical device of claim 11 wherein the central disk and each central annular segment has a parabolic optical phase profile at the design wavelength.
14 . The refractive optical device of claim 11 further comprising:
light blocking material disposed over the interface between the central disk and the innermost central annular segment and over the interface between each pair of adjacent annular segments, the light absorbing material effective to block light at the design wavelength.
15 . The refractive optical device of claim 14 wherein the GRIN lens is shaped as said disk having a thickness and the light blocking material disposed over each interface has a radial width of at least 1.5 times the thickness of the disk.
16 . The refractive optical device of claim 11 wherein the central disk and each annular segment of the GRIN lens comprises a liquid crystal material, the refractive optical device further comprising:
a pair of substrates confining the central disk and the plurality of annular segments; and
electrodes arranged to electrically bias the central disk and the plurality of annular segments;
wherein the GRIN lens and the electrodes form a variable power GRIN lens whose focus is electrically tunable using the electrodes.
17 . An augmented reality (AR) or virtual reality (VR) system including:
An AR or VR headset; and
a variable power left eye lens and a variable power right eye lens each comprising a refractive optical device as set forth in claim 16 , wherein the variable power left and right eye lenses are configured to provide accommodation for viewing of AR or VR content at different distances.
18 . The refractive optical device of claim 11 wherein the peripheral annular segments each have a fixed width W of at least 0.8 mm.
19 . A refractive optical device comprising:
a gradient refractive index (GRIN) lens shaped as a disk and including a central disk and a plurality of annular segments disposed around the central disk; and
light blocking material disposed over the interface between the central disk and the innermost central annular segment and over the interface between each pair of adjacent annular segments, the light absorbing material effective to block light at a design wavelength;
wherein:
the central disk and each annular segment is transparent at the design wavelength;
the central disk and each annular segment has a continuous optical phase profile at the design wavelength along a radial direction extending radially outward from a center of the central disk;
an optical phase discontinuity is present at the interface between the central disk and the innermost central annular segment and at the interface between each pair of adjacent annular segments;
the plurality of annular segments disposed around the central disk include a plurality of central annular segments disposed around the central disk and a plurality of peripheral annular segments disposed around the plurality of central annular segments;
radial widths of the central annular segments decrease with increasing distance away from the center of the central disk; and
the peripheral annular segments each have a fixed width W.
20 . The refractive optical device of claim 19 wherein the GRIN lens is shaped as said disk having a thickness and the light blocking material disposed over each interface has a radial width of at least 1.5 times the thickness of the disk.
21 . The refractive optical device of claim 19 wherein the light blocking material comprises chrome oxide.