Lighting device and primary optics for shaping far-field light emission of LED array and method of manufacture

1 . A lighting device comprising:

an LED array comprising rows and columns of light-emitting diode (LED) dies on a common substrate; and

a lens array over the array of LED dies,

wherein the lens array comprises a plurality of lenses each having a bullet-shaped cross-section and disposed over a respective row of the LED dies in the LED array such that an invariant axis of each lens is aligned along a respective row of LEDs and an axis of periodicity of the lenses is perpendicular to the invariant axis, and

wherein each of the LED dies in the LED array is longer along the axis of periodicity than along the invariant axis.

2 . The lighting device of claim 1 , wherein each of the plurality of lenses comprises a single molded lens.

3 . The lighting device of claim 1 , wherein each of the plurality of lenses comprises a single molded hemispherical lens over at least one planar silicone layer.

4 . The lighting device of claim 1 , wherein an aspect ratio of each of the LED dies between 1:1.1 and 8:1.

5 . The lighting device of claim 1 , further comprising a first layer of a reflective material over the common substrate and surrounding each of the LED dies.

6 . The lighting device of claim 5 , further comprising a second layer of a reflective material over the first layer of reflective material and covering a portion of an outer surface of each of the plurality of lenses, creating apertures through which portions of the lenses are exposed.

7 . The lighting device of claim 6 , wherein a height of the second layer of reflective material above the first layer of reflective material is between 0.1 μm and a full height of the lens.

8 . The lighting device of claim 6 , wherein the first reflective material and the second reflective material are either a dispensed reflective side coat (DSC) or an optical side coat (OSC) applied by other means.

9 . The lighting device of claim 1 , wherein each of the plurality of lenses is narrower along the axis of periodicity than a pitch between adjacent LED dies.

10 . The lighting device of claim 9 , wherein a side wall of each of the plurality of lenses is nominally vertical.

11 . The lighting device of claim 1 , wherein at least two of:

each of the LED dies in the LED array is longer along the axis of periodicity than along the invariant axis;

the lighting device comprises a layer of reflective material over the substrate covering a portion of an outer surface of each of the plurality of lenses, creating apertures through which portions of the lenses are exposed; or

each of the plurality of lenses is thinner along the axis of periodicity than the pitch between adjacent LED dies.

12 . The lighting device of claim 1 , wherein the lighting device is one of a display-based tail light, a standard tail light, a signaling light, a daytime running light, decorative trim, a pool light, a headlight, or other matrix display.

13 . A method of manufacturing a lighting device, the method comprising:

forming an LED array by arranging rows and columns of light-emitting diode (LED) dies on a common substrate;

selecting an aspect ratio for the LED dies between 1.1:1 and 8:1 with each of the LED dies being longer along the axis of periodicity than along the invariant axis such that light emission from each of the LED dies appears square on direct view;

forming a lens array to have a plurality of lenses, each having a bullet-shaped cross-section;

aligning the lens array over the LED array such that each of the lenses is aligned along a respective row of the LEDs and an axis of periodicity of the lenses is perpendicular to the invariant axis.

14 . The method of claim 13 , further comprising forming a layer of a reflective material over the common substrate and covering a portion of an outer surface of each of the plurality of lenses, creating apertures through which portions of the lenses are exposed.