Micro assembled LED displays and lighting elements
View Patent ↗The disclosed technology provides micro-assembled micro-LED displays and lighting elements using arrays of micro-LEDs that are too small (e.g., micro-LEDs with a width or diameter of 10 μm to 50 μm), numerous, or fragile to assemble by conventional means. The disclosed technology provides for micro-LED displays and lighting elements assembled using micro-transfer printing technology. The micro-LEDs can be prepared on a native substrate and printed to a display substrate (e.g., plastic, metal, glass, or other materials), thereby obviating the manufacture of the micro-LEDs on the display substrate. In certain embodiments, the display substrate is transparent and/or flexible.
1. A micro-LED display, comprising:
a display substrate that is at least partially transparent;
an array of color-conversion structures disposed on the display substrate, each color-conversion structure comprising a color-conversion material that converts light of a relatively higher frequency to light of a relatively lower frequency; and
an array of micro-LEDs separate from the color-conversion structures, each micro-LED in the array of micro-LEDs disposed on and in direct contact with a corresponding one of the color-conversion structures in the array of color-conversion structures, so that the color-conversion structures are between the micro-LEDs and the display substrate.
2. The display of claim 1 , wherein the display substrate comprises an array of recesses in which the color-conversion material(s) are located.
3. The display of claim 2 , wherein the recesses are filled with the color-conversion material(s).
4. The display of claim 1 , wherein the micro-LEDs are disposed on the color-conversion material(s) on a side of the color-conversion material(s) opposite the display substrate so that most or all of the light emitted from the micro-LEDs emits downward through the color-conversion material(s) and the display substrate.
5. The display of claim 1 , comprising one or more reflective structures substantially covering a side of the micro-LEDs opposite the display substrate, so that the micro-LEDs reflect emitted light toward the display substrates.
6. The display of claim 5 , wherein the one or more reflective structures comprise array connection metals or micro-LED contacts.
7. A micro-LED display, comprising:
a display substrate;
an array of micro-LEDs on and in contact with the display substrate; and
an array of color-conversion structures separate from the micro-LED structures, each color-conversion structure in the array of color-conversion structures disposed directly on a corresponding one of the micro-LEDs in the array of micro-LEDs so that the color-conversion structures are between the micro-LEDs and the display substrate, wherein each color-conversion structure comprises a color-conversion material that converts light of a relatively higher frequency to light of a relatively lower frequency.
8. The display of claim 7 , wherein the color-conversion material(s) are disposed on top of or at least partially surrounding the micro-LEDs on a side of the micro-LEDs opposite the display substrate.
9. The display of claim 1 , wherein the color-conversion material(s) comprise(s) at least one member selected from the group consisting of a phosphor-bearing gel, a phosphor-bearing resin, a phosphor ceramic, and a single-crystal phosphor.
10. The display of claim 1 , wherein the color-conversion material(s) are chips of direct band gap semiconductors.
11. The display of claim 1 , wherein the color-conversion material(s) at least partially surrounding the micro-LEDs.
12. The display of claim 1 , comprising supplementary mirror structures on the display substrate.
13. The display of claim 1 , wherein each micro-LED has an LED substrate separate from the display substrate.
14. The display of claim 1 , wherein the micro-LEDs are formed in a native substrate distinct and separate from the display substrate.
15. The display of claim 1 , wherein the display substrate has a thickness from 5 to 10 microns, 10 to 50 microns, 50 to 100 microns, 100 to 200 microns, 200 to 500 microns, 0.5 to 1 mm, 1 mm to 5 mm, 5 mm to 10 mm, or 10 mm to 20 mm.
16. The display of claim 1 , wherein each micro-LED has a width from 2 to 5 μm, 5 to 10 μm, 10 to 20 μm, or 20 to 50 μm.
17. The display of claim 1 , wherein each micro-LED has a length from 2 to 5 μm, 5 to 10 μm, 10 to 20 μm, or 20 to 50 μm.
18. The display of claim 1 , wherein each micro-LED has with a height from 2 to 5 μm, 4 to 10 μm, 10 to 20 μm, or 20 to 50 μm.
19. The display of claim 1 , wherein each micro-LED has an anode and a cathode disposed on a same side of the respective micro-LED.
20. The display of claim 19 , wherein the anode and cathode of a respective light emitter are horizontally separated by a horizontal distance, wherein the horizontal distance is from 100 nm to 500 nm, 500 nm to 1 micron, 1 micron to 20 microns, 20 microns to 50 microns, or 50 microns to 100 microns.
21. The display of claim 1 , comprising one or more electrodes disposed on the common side of the display substrate and the micro-LEDs are electrically connected to one or more of the electrodes.
22. The display of claim 1 , comprising one or more control circuits are disposed on the common side of the display substrate and each micro-LED is electrically connected to one of the control circuits.
23. The display of claim 1 , wherein the micro-LEDs include at least a portion of a tether.