Optical displays
An apparatus for providing an optical display includes an optical substrate for propagating light received from a light source, a first set of one or more switchable diffractive elements in the substrate, and a second set of one or more switchable diffractive elements in the substrate. Each diffractive element in the second set corresponds to a diffractive element in the first set. Each of the diffractive elements in the first and second sets is configured to switch between on and off states. One of the states is for diffracting light and the other state for allowing light to pass through. Each of the first set of diffractive elements is configured to diffract the light at an angle for propagation in the substrate. Each of the second set of diffractive elements is configured to diffract the light for display.
1. An apparatus for providing light from a light source to an eye location, comprising:
a substrate having a first glass layer and a second glass layer;
a first set of fold gratings disposed between the first glass layer and the second glass layer in the substrate arranged to receive light from the light source and to diffract the received light in a first direction as first diffracted light for propagation in the substrate; and
a second set of output gratings disposed between the first glass layer and the second glass layer in the substrate arranged to receive the first diffracted light and to diffract the first diffracted light in a second direction as second diffracted light to the eye location, wherein the first direction is different from the second direction, wherein the first set of fold gratings, the second set of output gratings, the first glass layer and the second glass layer are part of a same waveguide structure.
2. The apparatus of claim 1 , wherein the first direction is orthogonal to the second direction.
3. The apparatus of claim 1 , wherein the first direction is orthogonal to an incident light direction of the light received from the light source.
4. The apparatus of claim 1 , further comprising a collimating device for providing light from the light source to the first set of fold gratings.
5. The apparatus of claim 4 , wherein the collimating device comprises a diffractive lens.
6. The apparatus of claim 1 , wherein the apparatus is mounted in a head mounted display, a heads-up display, or eyewear.
7. The apparatus of claim 1 , wherein the first set of fold gratings and the second set of output gratings comprise one or more of Bragg gratings or gratings recorded in holographic polymer dispersed liquid crystal.
8. The apparatus of claim 1 , wherein the diffractive power of each of the first set of fold gratings is the same as each of the second set of output gratings.
9. The apparatus of claim 1 , wherein the light source is a laser.
10. The apparatus of claim 1 , wherein the light from the light source comprises light waves from varying angles, and each of the gratings in the first and second sets are configured to diffract light from a specific set of angles.
11. The apparatus of claim 1 , wherein the apparatus is a holographic waveguide display.
12. The apparatus of claim 1 , wherein the apparatus expands the field of view of the light source.
13. An apparatus for providing light from a light source to an eye location, comprising:
a substrate having a first glass layer and a second glass layer;
a first set of fold gratings, disposed between the first glass layer and the second glass layer, arranged to receive light from the light source and to diffract the received light in a first direction as first diffracted light for propagation in the substrate; and
a second set of output gratings, disposed between the first glass layer and the second glass layer, arranged to receive the first diffracted light and to diffract the first diffracted light in a second direction as second diffracted light to the eye location, wherein the first direction is different from the second direction,
wherein the first set of fold gratings, the second set of output grating, the first glass layer and the second glass layer are part of a same waveguide structure,
wherein the display expands the field of view of the light source.
14. The apparatus of claim 13 , wherein the first direction is orthogonal to the second direction.
15. The apparatus of claim 13 , wherein the first direction is orthogonal to an incident light direction of the light received from the light source.
16. The apparatus of claim 13 , wherein the field of view provided for display is greater than 30 degrees.
17. The apparatus of claim 13 , wherein the apparatus is a holographic waveguide display.
18. An apparatus for providing light from a light source to an eye location, comprising:
a substrate having a first glass layer and a second glass layer;
a first set of fold gratings in a first region of a substrate, disposed between the first glass layer and the second glass layer, arranged to receive light from the light source and to diffract the received light in a first direction as first diffracted light;
a second set of output gratings in a second region of the substrate, disposed between the first glass layer and the second glass layer, arranged to receive the first diffracted light and to diffract the first diffracted light to the eye location in a second direction as second diffracted light, wherein the first direction is orthogonal to the second direction; and
a third region, without gratings, of the substrate, disposed between the first glass layer and the second glass layer, arranged between the first and second regions, and arranged to propagate the first diffracted light to the second set of output gratings,
wherein the first set of fold gratings, the second set of output grating, the first glass layer, the second glass layer and the third region are part of a same waveguide structure.