DIMMING ELEMENT WITH EDGE-MOUNTED ILLUMINATORS FOR AN OPTICAL ASSEMBLY

1 . An optical assembly, comprising:

an eyeward side and a backside, wherein the optical assembly is configured to receive visible scene light at the backside of the optical assembly and to direct the visible scene light on an optical path toward the eyeward side;

a dimming element disposed on the optical path between the eyeward side and the backside, wherein the dimming element includes a photochromic material that is configured to darken in response to exposure to a range of light wavelengths; and

at least one illuminator coupled to an edge of the dimming element, wherein the at least one illuminator is configured to selectively emit an activation light within the range of light wavelengths to activate a darkening of the photochromic material to dim the visible scene light.

2 . The optical assembly of claim 1 , wherein the dimming element comprises a lens, and wherein the photochromic material is included in a coating on at least one optical surface of the lens.

3 . The optical assembly of claim 1 , wherein the dimming element comprises a lens, and wherein the photochromic material is included in a dye embedded within the lens.

4 . The optical assembly of claim 1 , wherein the dimming element is configured to guide the activation light by total internal reflection to activate the darkening of the photochromic material.

5 . The optical assembly of claim 4 , wherein the at least on illuminator is configured to selectively emit the activation light to darken the photochromic material across a field of view provided by the optical assembly.

6 . The optical assembly of claim 5 , further comprising a reflective coating disposed on the edge of the dimming element, wherein the reflective coating is configured to reflect the activation light within the dimming element.

7 . The optical assembly of claim 1 , wherein the at least one illuminator is configured to selectively emit the activation light to darken the photochromic material for a region that is less than a field of view provided by the optical assembly.

8 . The optical assembly of claim 1 , wherein the activation light comprises non-visible light, ultraviolet light, infrared light, or violet light.

9 . The optical assembly of claim 1 , further comprising:

a display layer disposed on the optical path between the eyeward side of the optical assembly and the dimming element, wherein the display layer is configured to direct visible display light toward the eyeward side.

10 . A head-mounted device, comprising:

a frame; and

an optical assembly secured within the frame, wherein the optical assembly is configured to receive visible scene light at a backside of the optical assembly and to direct the visible scene light on an optical path toward an eyeward side of the optical assembly, wherein the optical assembly includes:

a dimming element disposed on the optical path between the eyeward side and the backside, wherein the dimming element includes a photochromic material that is configured to darken in response to exposure to a range of light wavelengths; and

at least one illuminator coupled to an edge of the dimming element, wherein the at least one illuminator is configured to selectively emit an activation light within the range of light wavelengths to activate a darkening of the photochromic material to dim the visible scene light.

11 . The head-mounted device of claim 10 , wherein the dimming element is configured to guide the activation light by total internal reflection to activate the darkening of the photochromic material.

12 . The head-mounted device of claim 11 , wherein the at least one illuminator is configured to selectively emit the activation light to darken the photochromic material across a field of view provided by the optical assembly.

13 . The head-mounted device of claim 12 , further comprising a reflective coating disposed on the edge of the dimming element, wherein the reflective coating is configured to reflect the activation light within the dimming element.

14 . The head-mounted device of claim 13 , wherein the frame positioned to absorb activation light that escapes the dimming element through the at least one illuminator at the edge of the dimming element.

15 . The head-mounted device of claim 10 , further comprising:

a computing device included in the frame and configured to control the at least one illuminator to emit the activation light.

16 . The head-mounted device of claim 10 , wherein the activation light comprises non-visible light, ultraviolet light, infrared light, or violet light.

17 . The head-mounted device of claim 10 , wherein the optical assembly further comprises:

a display layer disposed on the optical path between the eyeward side of the optical assembly and the dimming element, wherein the display layer is configured to direct visible display light toward the eyeward side.

18 . An optical assembly, comprising:

a dimming element that includes:

a lens; and

a photochromic material, wherein the photochromic material is included in a coating on an optical surface of the lens or in a dye embedded within the lens, wherein the photochromic material is configured to darken in response to exposure to a range of light wavelengths; and

a plurality of illuminators coupled to an edge of the lens, wherein the plurality of illuminators are configured to selectively emit an activation light within the range of light wavelengths to activate a darkening of the photochromic material to dim visible scene light, and wherein the dimming element is configured to guide the activation light by total internal reflection.

19 . The optical assembly of claim 18 , wherein the dimming element further comprises a reflective coating disposed on the edge of the dimming element, wherein the reflective coating is configured to reflect the activation light within the dimming element.

20 . The optical assembly of claim 18 , wherein the activation light comprises non-visible light, ultraviolet light, infrared light, or violet light.