Photochromic optical element

1. A head mounted device comprising:

a frame including electronics that dissipate heat when the head mounted device is turned on; and

an optical element mounted in the frame, wherein the optical element receives the heat dissipated by the electronics in the frame, the optical element comprising:

a scene-side transparent boundary layer;

an eyeward transparent boundary layer; and

a solution disposed between the scene-side transparent boundary layer and the eyeward transparent boundary layer, the solution including liquid crystals co-mingled with oblong photochromic dye molecules, wherein the liquid crystals are configured to become increasingly disordered in response to increased temperature, and wherein the oblong photochromic dye molecules are configured to align with the liquid crystals and increase a cross-section of the oblong photochromic dye molecules with respect to incoming light as the liquid crystals increase in disorder,

wherein the oblong photochromic dye molecules are matched to the liquid crystal to offset a decrease in absorption of the oblong photochromic dye molecules in response to increased temperature such that a transmission of the incoming light is approximately equal across the optical element when a temperature gradient exists across the optical element.

2. The head mounted device of claim 1 , wherein the incoming light is incident upon the scene-side transparent boundary layer approximately normal to the scene-side transparent boundary layer, and wherein long axes of the liquid crystals are self-aligned approximately normal to the scene-side transparent boundary layer and the eyeward transparent boundary layer.

3. The head mounted device of claim 1 , wherein a first refractive index of the liquid crystal is substantially equal to a second refractive index of the oblong photochromic dye molecules.

4. The head mounted device of claim 1 , wherein the liquid crystals are rod-shaped liquid crystal molecules.

5. The head mounted device of claim 1 , wherein the optical element further includes a display optical element configured to present images to an eye of a wearer of the head mounted device.

6. An optical element comprising:

a scene-side transparent boundary layer;

an eyeward transparent boundary layer; and

a solution disposed between the scene-side transparent boundary layer and the eyeward transparent boundary layer, the solution including liquid crystals co-mingled with oblong photochromic dye molecules, wherein the liquid crystals are configured to become increasingly disordered in response to increased temperature, and wherein the oblong photochromic dye molecules are configured to align with the liquid crystals and increase a cross-section of the oblong photochromic dye molecules with respect to incoming light as the liquid crystals increase in disorder,

wherein the oblong photochromic dye molecules are matched to the liquid crystal to offset a decrease in absorption of the oblong photochromic dye molecules in response to increased temperature such that a transmission of the incoming light is approximately equal across the optical element when a temperature gradient exists across the optical element.

7. The optical element of claim 6 , wherein the incoming light is incident upon the scene-side transparent boundary layer approximately normal to the scene-side transparent boundary layer, and wherein long axes of the liquid crystals are self-aligned approximately normal to the scene-side transparent boundary layer and the eyeward transparent boundary layer.

8. The optical element of claim 6 , wherein a first refractive index of the liquid crystal is substantially equal to a second refractive index of the oblong photochromic dye molecules.

9. The optical element of claim 6 , wherein the liquid crystals are rod-shaped liquid crystal molecules.

10. The optical element of claim 6 further comprising:

a display optical element configured to present images to an eye of a wearer of a head mounted device that includes the optical element.

11. An optical element comprising:

a first transparent conductive layer;

a second transparent conductive layer; and

a solution disposed between the first transparent conductive layer and the second transparent conductive layer, the solution including liquid crystals co-mingled with oblong photochromic dye molecules, wherein a voltage applied across the first transparent conductive layer and the second transparent conductive layer controls an alignment of the liquid crystals with respect to the first transparent conductive layer and the second transparent conductive layer, wherein the liquid crystals are configured to become increasingly disordered in response to increased temperature, and wherein the oblong photochromic dye molecules are configured to align with the liquid crystals and increase a cross-section of the oblong photochromic dye molecules with respect to incoming light as the liquid crystals increase in disorder,

wherein the oblong photochromic dye molecules are matched to the liquid crystal to offset a decrease in absorption of the oblong photochromic dye molecules in response to increased temperature such that a transmission of the incoming light is approximately equal across the optical element when a temperature gradient exists across the optical element.

12. The optical element of claim 11 , wherein increasing the voltage across the first transparent conductive layer and the second transparent conductive layer increases a light transmission through the optical element by increasing the alignment of the liquid crystals between the first transparent conductive layer and a second transparent conductive layer.

13. The optical element of claim 11 , wherein a first refractive index of the liquid crystal is substantially equal to a second refractive index of the oblong photochromic dye molecules.

14. The optical element of claim 11 , wherein the first transparent conductive layer and the second transparent conductive layer include indium tin oxide (ITO).