Optimized optical element for LED
A lens comprises a base and a head where the base may have one or more side walls with a straight cross-section and the head may have one or more surfaces with a curved cross-section forming an apex at the top of the lens with an effective radius of curvature. The base thickness, the total thickness of the lens, and/or the effective radius of curvature may be tuned to improve emission directionality and/or light extraction efficiency of an LED over which the lens is disposed. Individual ones of the lens may be disposed over individual LEDs in an array. To reduce crosstalk.
1 . An optical element comprising:
a base portion comprising a flat surface having an outer perimeter and one or more side walls angled inward toward a central axis of the base portion, the central axis oriented perpendicular to the flat surface, each side wall of the one or more side walls having a perimeter end along the outer perimeter of the flat surface and a distal end that is distal from the flat surface, the perimeter of the flat surface having a diameter of 0.5 mm to 5 mm; and
an upper portion comprising one or more surfaces collectively extending from the distal end of each of the one or more side walls to form an apex centered on the central axis, the upper portion having an effective radius of curvature of 700 microns to 1100 microns at the apex,
wherein the distance measured parallel to the central axis from the flat surface to the apex is 1000 microns to 1300 microns,
wherein the one or more surfaces of the upper portion comprises two or more surfaces that collectively form polygonal shapes in planes perpendicular to the flat surface and including the central axis.
2 . The optical element of claim 1 , wherein the distance measured parallel to the central axis from the flat surface of the base portion to the distal end of the base side walls is 100 microns to 700 microns.
3 . The optical element of claim 1 , wherein the distance measured parallel to the central axis from the flat surface to the apex is 900 microns to 1300 microns.
4 . The optical element of claim 1 , wherein the upper portion is integral with the base portion.
5 . The optical element of claim 1 , wherein:
the outer perimeter of the flat surface is circular or elliptical;
the base portion comprises only a single continuous side wall extending along the outer perimeter of the flat surface and angled toward the central axis; and
the single continuous side wall has circular or elliptical cross-sectional shapes in at least some planes parallel to the flat surface corresponding to the circular or elliptical shape of the outer perimeter.
6 . The optical element of claim 5 , wherein the single continuous side wall has polygonal shapes in planes perpendicular to the flat surface and including the central axis.
7 . The optical element of claim 5 , wherein the upper portion has a lower end extending from the distal end of the base portion, the lower end forming an inner perimeter of the optical element that is circular or elliptical.
8 . The optical element of claim 1 , wherein the base portion comprises a same material as the upper portion.
9 . The optical element of claim 1 , wherein the base portion comprises a different material as the upper portion.
10 . The optical element of claim 1 , wherein:
the base portion is integral with the upper portion,
the base portion and the upper portion comprise silicone, and
the base portion comprises a hollow at the flat surface through which the central axis extends.
11 . A light emitting device, comprising:
a substrate;
an LED disposed on the substrate; and
the optical element of claim 1 disposed on the substrate and the LED.
12 . The light emitting device of claim 11 , wherein the optical element is disposed in direct contact with the substrate and the LED.
13 . The light emitting device of claim 11 , wherein the LED comprises InGaN and is configured to emit blue light.
14 . A light emitting array, comprising:
a plurality of substrates;
a plurality of LEDs disposed on the substrate; and
a plurality of optical elements, each of the optical elements comprising the optical element of claim 1 disposed on a respective one of the substrates and on a respective one of the LEDs.
15 . An optical element comprising:
a base portion comprising a flat surface having an outer perimeter and a single continuous side wall extending along the outer perimeter of the flat surface and angled toward a central axis of the base portion, the central axis oriented perpendicular to the flat surface, the single continuous side wall having a perimeter end along the outer perimeter of the flat surface and a distal end that is distal from the flat surface, the single continuous side wall having circular or elliptical cross-sectional shapes in at least some planes parallel to the flat surface corresponding to the circular or elliptical shape of the outer perimeter, the perimeter of the flat surface having a diameter of 0.5 mm to 5 mm, the outer perimeter of the flat surface being circular or elliptical; and
an upper portion comprising one or more surfaces collectively extending from the distal end of the single continuous side wall to form an apex centered on the central axis, the upper portion having an effective radius of curvature of 700 microns to 1100 microns at the apex;
wherein the distance measured parallel to the central axis from the flat surface to the apex is 1000 microns to 1300 microns, and
wherein the upper portion has a lower end extending from the distal end of the base portion, the lower end forming an inner perimeter of the optical element that is polygonal.
16 . The optical element of claim 15 , wherein the one or more surfaces of the upper portion comprises two or more surfaces that collectively form polygonal shapes in planes perpendicular to the flat surface and including the central axis.
17 . An optical element comprising:
a base portion comprising a flat surface having an outer perimeter and one or more side walls angled inward toward a central axis of the base portion, the central axis oriented perpendicular to the flat surface, each side wall of the one or more side walls having a perimeter end along the outer perimeter of the flat surface and a distal end that is distal from the flat surface, the perimeter of the flat surface having a diameter of 0.5 mm to 5 mm; and
an upper portion comprising one or more surfaces collectively extending from the distal end of each of the one or more side walls to form an apex centered on the central axis, the upper portion having an effective radius of curvature of 700 microns to 1100 microns at the apex;
wherein the distance measured parallel to the central axis from the flat surface to the apex is 1000 microns to 1300 microns; and
wherein the one or more surfaces of the upper portion includes two or more surfaces that are each a polygon.