Lighting device with switching material
A lighting device comprises a light-emitting module with light-emitting elements, wherein the light-emitting elements are arranged adjacent to each other and are configured to emit light towards a light-emitting side. The light-emitting module is configured such that the light-emitting elements can be addressed partially independently of each other, such that some may be brought into a switched-on state while others are brought into a switched-off state. A top layer is disposed on the light-emitting module at the light-emitting side. Further comprising a switching material capable of a reversible change in transmittance for the light emitted by changing to a higher transmittance in regions where the top layer situated on light-emitting elements in the switched-on state or to a lower transmittance in regions of the top layer situated in the switched-off state. The invention further refers to methods for producing and operating a lighting device and using a lighting device.
1. A device comprising:
an adjustable-transmittance layer having independently-addressable regions configured to change states between a lower transmittance state and a higher transmittance state that has a higher transmittance than the lower transmittance state to light of a predetermined wavelength, each region having a porous structure that comprises:
a non-light absorbing material having a plurality of pores, and
material disposed in the pores, a difference between a refractive index of the non-light absorbing material structure and a refractive index of the material disposed in the pores configured to change in response to an external stimulus to change the state of at least one of the regions.
2. The device according to claim 1 , wherein the external stimulus includes temperature.
3. The device according to claim 1 , further comprising a controller configured to independently adjust a temperature of each region to provide the external stimulus.
4. The device according to claim 1 , wherein the external stimulus applied to each region is waste heat generated by another element of the device provided by convection.
5. The device according to claim 1 , wherein the external stimulus applied to one of the regions is waste heat generated by another element of the device provided by a heat conduction element coupled to the other element and to the one of the regions.
6. The device according to claim 1 , wherein the external stimulus applied to one of the regions is waste heat generated by a wavelength conversion element configured to provide the light of the predetermined wavelength to the one of the regions.
7. The device according to claim 1 , wherein the external stimulus applied to one of the regions is waste heat generated by a light emitting device configured to generate light of the predetermined wavelength for the one of the regions.
8. The device according to claim 1 , wherein the adjustable-transmittance layer comprises another layer having regions of an electrochromic material whose transmittance changes with applied voltage.
9. The device according to claim 1 , wherein the porous structure of each region is encapsulated within a protective material.
10. The device according to claim 1 , wherein the pores have at least one characteristic dimension that is sub-micron in size and the material disposed in the pores is a polymer matrix.
11. The device according to claim 1 , wherein:
in the higher transmittance state, each region is substantially transparent to the light of the predetermined wavelength, and
in the lower transmittance state, each region is substantially opaque to the light of the predetermined wavelength.
12. The device according to claim 1 , wherein:
in the higher transmittance state, each region is substantially transparent to the light of the predetermined wavelength,
in the lower transmittance state, each region is translucent to the light of the predetermined wavelength, and
the adjustable-transmittance layer is used instead of a diffusion layer in the device.
13. The device according to claim 1 , wherein the material comprises a porous particle having at least one pore disposed therein.
14. The device according to claim 1 , wherein the non-light absorbing material structure comprises a mesh slab and the pores comprise an interconnected network of sub-micron pores.
15. The device according to claim 2 , wherein each region is configured to switch from the lower transmittance state to the higher transmittance state with increasing temperature.
16. The device according to claim 10 , wherein the polymer matrix is silicone-based and the non-light absorbing material structure is formed from porous silica.