Nanostructured meta-materials and meta-surfaces to collimate light emissions from LEDs
A system, method and device for collimating the output of a light emitting diode (LED) are disclosed. The system, method and device include an LED substrate including a top surface from which the light is emitted, and an array of subwavelength scattering antennas positioned within the emitted light path, the array of subwavelength scattering antennas configured to select directions of scatter of the LED emitted light to provide collimated light output from the device. The array may be aligned perpendicular to the plane of propagation of the light emitted from the LED and may be positioned adjacent to the top surface. The array may be at least partially, or completely, positioned within the LED substrate. The array may be spaced a distance from the top surface and the spacing may be achieved using a dielectric spacer adjacent to the top surface. The array may be positioned within the dielectric spacer.
1. A light emitting device comprising:
a light emitting diode comprising a light emitting surface through which light is emitted in operation of the light emitting device; and
at least a first array of light scattering antennas arranged in a plane parallel to the light emitting surface, each light scattering antenna having dimensions in the plane of the first array less than or equal to a free space wavelength of light emitted by the light emitting diode, the light scattering antennas having structural, optical, or structural and optical properties that vary with the spatial location of the light scattering antennas in the plane of the first array to affect phase and amplitude of light emitted through the light emitting surface in a spatially varying manner that collimates or partially collimates the light emitted through the light emitting surface.
2. The light emitting device of claim 1 , wherein a spacing between the light scattering antennas varies with the spatial location of the light scattering antennas in the plane of the first array.
3. The light emitting device of claim 1 , wherein shapes of the light scattering antennas vary with the spatial location of the light scattering antennas in the plane of the first array.
4. The light emitting device of claim 1 , wherein sizes of the light scattering antennas vary with the spatial location of the light scattering antennas in the plane of the first array.
5. The light emitting device of claim 1 , wherein refractive indices of the light scattering antennas vary with the spatial location of the light scattering antennas in the plane of the first array.
6. The light emitting device of claim 1 , wherein the light scattering antennas have structural, optical, or structural and optical properties that vary with distance from a center of the first array of light scattering antennas.
7. The light emitting device of claim 1 , wherein the light scattering antennas have dimensions perpendicular to the plane of the first array less than or equal to the free space wavelength of light emitted by the light emitting diode.
8. The light emitting device of claim 1 , wherein the light scattering antennas are external to the light emitting diode and arranged on the light emitting surface.
9. The light emitting device of claim 1 , wherein the light scattering antennas are located within the light emitting diode beneath the light emitting surface.
10. The light emitting device of claim 1 , wherein the light scattering antennas are external to the light emitting diode and spaced apart from the light emitting surface.
11. The light emitting device of claim 1 , comprising a second array of light scattering antennas arranged parallel to and spaced apart from the first array of light scattering antennas, each light scattering antenna in the second array having dimensions in the plane of the second array less than or equal to the free space wavelength of light emitted by the light emitting diode, the light scattering antennas in the second array having structural, optical, or structural and optical properties that vary with the spatial location of the light scattering antennas in the plane of the second array to affect phase and amplitude of light emitted through the light emitting surface in a spatially varying manner that in combination with the first array of light scattering antennas collimates or partially collimates the light emitted through the light emitting surface.
12. The light emitting device of claim 11 , wherein the light scattering antennas of the first array of light scattering antennas are external to the light emitting diode and arranged on the light emitting surface and the light scattering antennas of the second array of light scattering antennas are also external to the light emitting diode.
13. The light emitting device of claim 12 , wherein:
the light scattering antennas of the first array of light scattering antennas have structural, optical, or structural and optical properties that vary with distance from a center of the first array of light scattering antennas; and
the light scattering antennas of the second array of light scattering antennas have structural, optical, or structural and optical properties that vary with distance from a center of the second array of light scattering antennas.
14. The light emitting device of claim 13 , wherein:
the light scattering antennas of the first array of light scattering antennas have dimensions perpendicular to the plane of the first array of light scattering antennas less than or equal to the free space wavelength of light emitted by the light emitting diode; and
the light scattering antennas of the second array of light scattering antennas have dimensions perpendicular to the plane of the second array of light scattering antennas less than or equal to the free space wavelength of light emitted by the light emitting diode.
15. The light emitting device of claim 11 , wherein the light scattering antennas of the first array of light scattering antennas are located within the light emitting diode beneath the light emitting surface.
16. The light emitting device of claim 15 , wherein:
the light scattering antennas of the first array of light scattering antennas have structural, optical, or structural and optical properties that vary with distance from a center of the first array of light scattering antennas; and
the light scattering antennas of the second array of light scattering antennas have structural, optical, or structural and optical properties that vary with distance from a center of the second array of light scattering antennas.
17. The light emitting device of claim 16 , wherein:
the light scattering antennas of the first array of light scattering antennas have dimensions perpendicular to the plane of the first array of light scattering antennas less than or equal to the free space wavelength of light emitted by the light emitting diode; and
the light scattering antennas of the second array of light scattering antennas have dimensions perpendicular to the plane of the second array less than or equal to the free space wavelength of light emitted by the light emitting diode.
18. The light emitting device of claim 11 , wherein the light scattering antennas of the first array of light scattering antennas are external to the light emitting diode and spaced apart from the light emitting surface and the light scattering antennas of the second array are also external to the light emitting diode.
19. The light emitting device of claim 18 , wherein:
the light scattering antennas of the first array of light scattering antennas have structural, optical, or structural and optical properties that vary with distance from a center of the first array of light scattering antennas; and
the light scattering antennas of the second array of light scattering antennas have structural, optical, or structural and optical properties that vary with distance from a center of the second array of light scattering antennas.
20. The light emitting device of claim 19 , wherein:
the light scattering antennas of the first array of light scattering antennas have dimensions perpendicular to the plane of the first array of light scattering antennas less than or equal to the free space wavelength of light emitted by the light emitting diode; and
the light scattering antennas of the second array of light scattering antennas have dimensions perpendicular to the plane of the second array less than or equal to the free space wavelength of light emitted by the light emitting diode.