Light-emitting diode display panel with micro lens array
A light-emitting diode (LED) display panel includes a substrate, a driver circuit array on the substrate and including a plurality of pixel driver circuits arranged in an array, an LED array including a plurality of LED dies each being coupled to one of the pixel driver circuits, a micro lens array including a plurality of micro lenses each corresponding to and being arranged over at least one of the LED dies, and an optical spacer formed between the LED array and the micro lens array.
1. A light-emitting diode (LED) display panel, comprising:
a substrate;
a driver circuit array on the substrate and including a plurality of pixel driver circuits arranged in an array;
an LED array including a plurality of LED dies each being coupled to one of the pixel driver circuits;
an electrical coupling layer formed between the driver circuit array and the LED array, the electrical coupling layer including a plurality of layers stacked in a vertical direction;
a micro lens array including a plurality of micro lenses each corresponding to and being arranged over at least one of the LED dies;
an optical spacer formed between the LED array and the micro lens array; and
a dielectric isolation layer arranged between the driver circuit array and the LED array, the dielectric isolation layer including first protrusion structures and second protrusion structures surrounding each of the first protrusion structures,
wherein the optical spacer includes a polymer material, a dielectric material, a semiconductor material, or an air gap,
the electrical coupling layer includes a plurality of electrical coupling pads arranged in an array and isolated from each other, each of the pixel driver circuits corresponding to one of the electrical coupling pads,
each first protrusion structure is formed between one of the electrical coupling pads and one of the pixel driver circuits, and has a through hole formed from an upper surface of the first protrusion structure to a lower surface of the first protrusion structure, at least a portion of the electrical coupling pad being arranged in the through hole, and
each of the first protrusion structures and the second protrusion structures surrounding the first protrusion structure define a continuous recess surrounding the first protrusion structure.
2. The LED display panel of claim 1 , wherein each of the micro lenses is aligned with the corresponding one of the LED dies.
3. The LED display panel of claim 1 , wherein the micro lens array is made of one of a polymer material, a dielectric material, or a semiconductor material.
4. The LED display panel of claim 1 , wherein the micro lenses are arranged in a triangular matrix, a square matrix, a rectangular matrix, or a hexagonal matrix.
5. The LED display panel of claim 1 , wherein each of the micro lenses has a lateral size larger than a lateral size of the corresponding at least one of the LED dies.
6. The LED display panel of claim 1 , wherein each of the micro lenses includes one of a spherical lens, an aspherical lens, or a Fresnel lens.
7. The LED display panel of claim 1 , wherein a bottom of each of the micro lenses has one of a circular shape, a square shape, a rectangular shape, a triangle shape, or a hexagonal shape.
8. The LED display panel of claim 1 , wherein the optical spacer and the micro lens array are formed of a same material.
9. The LED display panel of claim 1 , wherein each pixel driver circuit is coupled to two or more LED dies.
10. The LED display panel of claim 9 , wherein the two or more LED dies coupled to the same pixel driver circuit are coupled to each other in parallel.
11. The LED display panel of claim 1 , wherein each of the micro lenses corresponds to and is arranged over two or more of the LED dies.
12. The LED display panel of claim 1 , wherein:
the micro lens array includes a protrusion portion of a micro lens assembly,
the optical spacer includes a base portion of the micro lens assembly and a bonding polymer layer between the micro lens assembly and the LED array,
the micro lens assembly is made from a single piece of material separate from the LED array, and
the micro lens assembly is bonded to the LED array through the bonding polymer layer.
13. The LED display panel of claim 1 , further comprising:
a mechanical fixture holding the driver circuit wafer and the micro lens array,
wherein the optical spacer includes an air gap.
14. The LED display panel of claim 13 , wherein:
the micro lens array includes a protrusion portion of a micro lens assembly, and
the protrusion portion faces the LED array.
15. The LED display panel of claim 13 , wherein:
the micro lens array includes a protrusion portion of a micro lens assembly,
the micro lens assembly further includes a base portion supporting the protrusion portion,
the protrusion portion faces opposite to the LED array, and
the optical spacer further includes the base portion.
16. The LED display panel of claim 1 , wherein the LED array, the optical spacer, and the micro lens array are made from a same semiconductor epitaxial layer grown on a semiconductor growth substrate.
17. The LED display of claim 16 , wherein:
the optical spacer includes a plurality of spacer units separated and electrically isolated from each other, and
each of the spacer units corresponds to and is formed over one of the LED dies.