Patterned inorganic LED device

• US 7,919,342 B2
• Filed: 11/07/2008
• Issued: 04/05/2011
• Est. Priority Date: 03/05/2007
• Status: Expired due to Fees

• Current Assignee: Nanoco Technologies Limited (Nanoco Group Plc)
• Original Assignee: Eastman Kodak Company
• Inventors: Cok, Ronald S.
• Primary Examiner(s): Vu; David
• Assistant Examiner(s): Chi; Suberr
• Application Number:
  US12/266,775
• Publication Number:
  US 20090068918A1
• Time in Patent Office: 879 Days
• Field of Search: 313/503, 313/504, 313/506, 257/79, 257/88, 257/89, 257/93, 257/98, 257/99, 438/22, 438/26, 438/27, 438/29, 438/42, 438/46
• US Class Current: 438/42
• CPC Class Codes: H05B 33/145 Arrangements of the electroluminescent material

Abstract

A method of making an inorganic light-emitting diode display having a plurality of light-emitting elements including providing a substrate, and forming a plurality of patterned electrodes over the substrate. A raised area is formed around each patterned electrode to provide a well before depositing a dispersion containing inorganic, light-emissive core/shell nano-particles into each well. The dispersion is dried to form a light-emitting layer including the inorganic, light-emissive core/shell nano-particles. An unpatterned, common electrode is formed over the light-emitting layer. The light-emitting layer emits light by the recombination of holes and electrons supplied by the electrodes.

Claims

1. A method of making an inorganic light-emitting diode display having a plurality of light-emitting elements comprising:

(a) providing a substrate;

(b) forming a plurality of patterned electrodes over the substrate;

(c) forming a raised area around each patterned electrode to provide a well;

(d) depositing a dispersion containing inorganic, light-emissive core/shell nano-particles into each well;

(e) drying the dispersion to form a light-emitting layer comprising the inorganic, light-emissive core/shell nano-particles;

(f) forming an unpatterned, common electrode over the light-emitting layer;

(g) wherein the light-emitting layer emits light by the recombination of holes and electrons supplied by the electrodes; and

(h) forming a patterned conductive layer disposed over the unpatterned, common conductive layer.

2. The method of claim 1, further comprising providing a plurality of conductive or semi-conductive nano-particles in the dispersion.

3. The method according to claim 1, further comprising annealing the light-emitting layer after drying the dispersion.

4. The method according to claim 1, further comprising employing inkjet, spray, curtain, or hopper coating to deposit optical material into one or more wells.

5. The method according to claim 4 wherein the optical material is a color filter material, a light-scattering material, or a liquid material that self-aligns to form a lenslet.

6. The method according to claim 1 further including forming a patterned conductive layer in electrical contact with the common, unpatterned electrode.

7. The method according to claim 6 wherein the patterned conductive layer is substantially in contact with the common, unpatterned electrode in the raised areas and substantially free from contact with the common, unpatterned electrode in the areas within the well.

8. The method according to claim 6 wherein the patterned conductive layer forms the raised areas.

9. The method according to claim 1 wherein the patterned conductive layer is located at least partially on the raised areas.

10. The method according to claim 1 wherein the dispersion containing inorganic, light-emissive core/shell nano-particles is deposited into the wells by employing ink jet, spray deposition, curtain, or hopper coating.

11. The method according to claim 1 further comprising providing a plurality of dispersions, each dispersion containing different inorganic, light-emissive particles that emit different colors of light, and the different dispersions being deposited into different wells.

12. The method according to claim 1, wherein dispersion does not fill the well and the raised areas serve as barriers to prevent the diffusion of dispersions from one well to another.

13. The method according to claim 1, wherein the wells are greater than or equal to 1 micron deep.

14. The method according to claim 1, wherein the wells are greater than or equal to 3 microns deep.