Micro assembled LED displays and lighting elements

• US 9,991,423 B2
• Filed: 06/18/2015
• Issued: 06/05/2018
• Est. Priority Date: 06/18/2014
• Status: Active Grant

• Current Assignee: X Display Company Technology Limited (Sensinnovat BVBA)
• Original Assignee: X-Celeprint Limited
• Inventors: Bower, Christopher, Meitl, Matthew, Gomez, David, Bonafede, Salvatore, Kneeburg, David, Fecioru, Alin, Prevatte, Carl
• Primary Examiner(s): Toledo, Fernando L.
• Assistant Examiner(s): NGUYEN, LAWRENCE-LIN T
• Application Number:
  US14/743,940
• Publication Number:
  US 20150372051A1
• Time in Patent Office: 1,083 Days
• CPC Class Codes: F21V 9/08 for producing coloured light, e.g. monochromatic; for reducing intensity of light with provision for controlling the colour F21V9/40
• CPC Class Codes: F21Y 2105/10 comprising a two-dimensional array of point-like light-generating elements
• CPC Class Codes: F21Y 2113/13 comprising an assembly of point-like light sources
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: G02B 26/04 by periodically varying the intensity of light, e.g. using choppers shutters, diaphragms for cameras G03B9/00; devices for eliminating or reducing the effect of flicker in projection systems G03B21/40
• CPC Class Codes: G02F 1/167 by electrophoresis
• CPC Class Codes: G09G 2300/0452 Details of colour pixel setup, e.g. pixel composed of a red, a blue and two green components
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2310/0264 Details of driving circuits
• CPC Class Codes: G09G 3/22 using controlled light sources
• CPC Class Codes: G09G 3/32 semiconductive, e.g. using light-emitting diodes [LED]
• CPC Class Codes: H01L 2224/18 High density interconnect [HDI] connectors; Manufacturing methods related thereto
• CPC Class Codes: H01L 2224/73267 Layer and HDI connectors
• CPC Class Codes: H01L 2224/92244 the second connecting process involving a build-up interconnect
• CPC Class Codes: H01L 23/4821 Bridge structure with air gap
• CPC Class Codes: H01L 23/5381 Crossover interconnections, e.g. bridge stepovers
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 25/167 comprising optoelectronic devices, e.g. LED, photodiodes
• CPC Class Codes: H01L 27/156 two-dimensional arrays
• CPC Class Codes: H01L 33/20 with a particular shape, e.g. curved or truncated substrate
• CPC Class Codes: H01L 33/36 : characterised by the electrodes
• CPC Class Codes: H01L 33/38 : with a particular shape
• CPC Class Codes: H01L 33/385 : the electrode extending at least partially onto a side surface of the semiconductor body
• CPC Class Codes: H01L 33/405 : Reflective materials
• CPC Class Codes: H01L 33/48 : characterised by the semiconductor body packages
• CPC Class Codes: H01L 33/50 : Wavelength conversion elements
• CPC Class Codes: H01L 33/502 : Wavelength conversion materials
• CPC Class Codes: H01L 33/508 : having a non-uniform spatial arrangement or non-uniform concentration, e.g. patterned wavelength conversion layer, wavelength conversion layer with a concentration gradient of the wavelength conversion material
• CPC Class Codes: H01L 33/58 : Optical field-shaping elements
• CPC Class Codes: H01L 33/60 : Reflective elements
• CPC Class Codes: H01L 33/62 : Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls
• CPC Class Codes: H05K 1/0306 : Inorganic insulating substrates, e.g. ceramic, glass
• CPC Class Codes: H05K 1/09 : Use of materials for the conductive, e.g. metallic pattern
• CPC Class Codes: H05K 1/181 : associated with surface mounted components
• CPC Class Codes: H05K 1/182 : associated with components mounted in the printed circuit board, e.g. insert mounted components [IMC]
• CPC Class Codes: H05K 2201/0329 : Intrinsically conductive polymer [ICP]; Semiconductive polymer
• CPC Class Codes: H05K 2201/10106 : Light emitting diode [LED]
• CPC Class Codes: H05K 2201/10128 : Display
• CPC Class Codes: H05K 2201/10166 : Transistor
• CPC Class Codes: H05K 5/0017 : with operator interface units

Abstract

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.

Claims

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.

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 μ

m, 5 to 10 μ

m, 10 to 20 μ

m, or 20 to 50 μ

m.

17. The display of claim 1, wherein each micro-LED has a length from 2 to 5 μ

m, 5 to 10 μ

m, 10 to 20 μ

m, or 20 to 50 μ

m.

18. The display of claim 1, wherein each micro-LED has with a height from 2 to 5 μ

m, 4 to 10 μ

m, 10 to 20 μ

m, or 20 to 50 μ

m.

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.

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.