MICRO LED ARRAY AND MICRO LED DISPLAY PANEL
A micro LED array includes a first type epitaxial layer; a light emitting layer continuously formed on a top surface of the first type epitaxial layer; a second type epitaxial layer formed on a top surface of the light emitting layer; and a top contact formed on a top of the second type epitaxial layer, the top contact having a circular structure or a spiral structure.
1 . A micro LED array, comprising:
a first type epitaxial layer;
a light emitting layer continuously formed on a top surface of the first type epitaxial layer;
a second type epitaxial layer formed on a top surface of the light emitting layer; and
a top contact formed on a top of the second type epitaxial layer, the top contact having a circular structure or a spiral structure.
2 . The micro LED array according to claim 1 , wherein the top contact is transparent.
3 . The micro LED array according to claim 2 , wherein the top contact includes metal wires arranged in a pattern.
4 . The micro LED array according to claim 1 , wherein the second type epitaxial layer comprises:
a bottom continuous layer formed on the light emitting layer;
an upper mesa array comprising a plurality of upper mesas extending up from the bottom continuous layer, wherein the upper mesa comprises a plurality of projections and a plurality of sunken portions; and
a trench formed between adjacent ones of the upper mesas.
5 . The micro LED array according to claim 4 ,
wherein each of the plurality of projections comprises a sharp tip.
6 . The micro LED array according to claim 4 , wherein the plurality of projections are formed in an array.
7 . The micro LED array according to claim 6 , wherein the array of the plurality of projections is a photonic crystal array, and a cross-sectional shape of a photonic crystal is round or polygonal.
8 . The micro LED array according to claim 4 , wherein the upper mesa further comprises a center sub-mesa, and a top surface of the center sub-mesa is flat and the plurality of projections are formed around the center sub-mesa.
9 . The micro LED array according to claim 4 , wherein a height of the projections is in a range of 10 nm to 5000 nm.
10 . The micro LED array according to claim 4 , wherein the bottom continuous layer is a second bottom continuous layer, the upper mesa is a second upper mesa, the upper mesa array is a second upper mesa array, and the trench is a second trench; wherein the first type epitaxial layer comprising:
a first upper continuous layer;
a first bottom mesa array comprising a plurality of first bottom mesas, wherein the first bottom mesa array is formed at a bottom of the first upper continuous layer and extends down from the first upper continuous layer; and
a first trench formed between adjacent first bottom mesas.
11 . The micro LED array according to claim 10 , wherein a sidewall of the first trench is vertical to the first upper continuous layer.
12 . The micro LED array according to claim 11 , wherein an error angle between the sidewall of the first trench and the first upper continuous layer is not more than ±5°.
13 . The micro LED array according to claim 11 , wherein a depth to width ratio of the first trench is not less than 5.
14 . The micro LED array according to claim 13 , wherein a width of the first trench is from 100 nm to 3 μm.
15 . The micro LED array according to claim 10 , wherein a thickness of the second bottom continuous layer is from 2 nm to 15 nm, and a thickness of the first upper continuous layer is from 2 nm to 15 nm.
16 . The micro LED array according to claim 10 , wherein a width of the second trench is greater than a width of the first trench.
17 . The micro LED array according to claim 10 , further comprising an isolation structure formed in the second trench.
18 . The micro LED array according to claim 17 , wherein the isolation structure is not transparent, and a material of the isolation structure is metal or isolation material.
19 . The micro LED array according to claim 17 , wherein the isolation structure comprises an isolation core and a reflective shell formed on the isolation core.
20 . The micro LED array according to claim 19 , wherein a material of the isolation core is not metal, and a material of the reflective shell is metal.
21 . The micro LED array according to claim 17 , further comprising a top dielectric layer formed on the second type epitaxial layer and the isolation structure, and at least part surface of each second upper mesa is exposed from the top dielectric layer.
22 . The micro LED array according to claim 21 , further comprising a top conductive layer formed on the top dielectric layer and on the exposed surface of the second upper mesa.
23 . The micro LED array according to claim 22 , wherein the top contact is formed between the exposed surface of the second upper mesa and the top conductive layer.
24 . The micro LED array according to claim 23 , wherein an area of the top contact is less than half of an area of the second upper mesa.
25 . The micro LED array according to claim 22 , wherein a top surface of the top conductive layer is not flat, and conforms with a top surface of the top dielectric layer.
26 . The micro LED array according to claim 10 , further comprising a first bottom contact layer formed at a bottom surface of the first bottom mesa.
27 . The micro LED array according to claim 26 , further comprising:
a bottom dielectric layer formed at a bottom of the first bottom contact layer and filled in the first trench; and
a bottom via array comprising a plurality of bottom vias formed at the bottom of the first bottom contact layer, wherein one bottom via corresponds to one first bottom mesa.
28 . The micro LED array according to claim 27 , further comprising a bottom reflective layer formed under the first bottom mesa, filled in the first trench, and around the bottom via, wherein the bottom reflective layer is provided in the bottom dielectric layer.
29 . The micro LED array according to claim 28 , wherein the bottom reflective layer is a reflective trench in the first trench, and the bottom dielectric layer is filled in the reflective trench.
30 . The micro LED array according to claim 27 , further comprising a bottom reflective layer formed under the first bottom mesa and around the bottom via, wherein the bottom reflective layer is provided in the bottom dielectric layer.
31 . The micro LED array according to claim 27 , further comprising a second bottom contact layer formed at a bottom of the first bottom contact layer, wherein a material of second bottom contact layer is a reflective material.
32 . The micro LED array according to claim 31 , wherein an area of the second bottom contact layer corresponding to each first bottom mesa is not less than an area of a top surface of each bottom via.
33 . The micro LED array according to claim 31 , wherein a material of the first bottom contact layer is transparent conductive material, a material of the second bottom contact layer is metal, and a material of the bottom dielectric layer is SiO 2 or Si 3 N 4 .
34 . The micro LED array according to claim 27 , wherein a bottom of the bottom via extends down from a bottom of the first bottom contact layer.
35 . The micro LED array according to claim 22 , further comprising a transparent micro lens array comprising a plurality of micro lenses formed on a top surface of the top conductive layer.
36 . The micro LED array according to claim 22 , wherein the top conductive layer and the top dielectric layer are transparent.
37 . The micro LED array according to claim 22 , wherein a material of the top dielectric layer is SiO 2 or Si 3 N 4 , and a material of the top conductive layer is a transparent conductive material.
38 . The micro LED array according to claim 10 , wherein a material of the first type epitaxial layer is one of AlGaInP, InP, AlInP, GaAs, or GaP; a material of the second type epitaxial layer is one of AlGaInP, InP, AlInP, GaAs, or GaP; the light emitting layer is a quantum well layer; a diameter of the first bottom mesa is not greater than 50 μm; and a diameter of the second upper mesa is not greater than the diameter of the first bottom mesa.
39 . A micro LED display panel, comprising,
an integrated circuit (IC) backplane comprising:
a first dielectric layer formed on the IC backplane; and
a top pad array comprising a plurality of top pads formed in the first dielectric layer; and
a micro LED array bonded with the IC backplane, wherein the micro LED array comprises:
a first type epitaxial layer;
a light emitting layer continuously formed on a top surface of the first type epitaxial layer;
a second type epitaxial layer formed on a top surface of the light emitting layer; and
a top contact formed on a top of the second type epitaxial layer, the top contact having a circular structure or a spiral structure.