Light-extraction element including raspberry-like particles

• US 9,391,299 B2
• Filed: 12/09/2013
• Issued: 07/12/2016
• Est. Priority Date: 05/08/2013
• Status: Active Grant

• Current Assignee: Industrial Technology Research Institute
• Original Assignee: Industrial Technology Research Institute
• Inventors: Chien, Pei-Chi, Chen, Ping-Chen
• Primary Examiner(s): GORDON, MATTHEW E
• Application Number:
  US14/100,474
• Publication Number:
  US 20140332773A1
• Time in Patent Office: 946 Days
• Field of Search: 257/40
• US Class Current: 1/1
• CPC Class Codes: G02B 5/0242 by means of dispersed particles
• CPC Class Codes: H10K 50/854 comprising scattering means
• CPC Class Codes: Y10T 428/2848 Three or more layers

Abstract

The invention provides a light-extraction element, comprising a light-diffusion layer which including a resin; and a plurality of raspberry-like particles uniformly dispersed in the resin, wherein the raspberry-like particles feature a surface with a plurality of round bumps, and the plurality of raspberry-like particles are composed of a material having a single reflective index. The invention also provides a light-emitting device, including a pair of electrodes composed of an anode and a cathode; an organic light-emitting unit disposed between the pair of electrodes, wherein the organic light-emitting unit includes a light-emitting layer; and a light-extraction element which is disposed on a light-emitting surface of the light-emitting device.

Claims

1. A light-extraction element, comprising:

a light-diffusion layer, the light-diffusion layer comprising;

a resin; and

a plurality of raspberry-like particles uniformly dispersed in the resin, wherein the raspberry-like particles feature a surface contour with a plurality of round bumps, and the plurality of raspberry-like particles are composed of a material having a single reflective index, wherein the plurality of raspberry-like particles per se are primary particles and has a homogeneous cross-section, wherein the homogeneous cross-section has no interface, wherein the raspberry-like particles are used as diffusion materials in the light-extraction element and the scattering caused by the surface contour of the raspberry-like particles enhances the light-extraction efficiency and reduces the color shift.

2. The light-extraction element as claimed in claim 1, wherein the light-diffusion layer further comprises an aggregate form of the plurality of raspberry-like particles.

3. The light-extraction element as claimed in claim 1, wherein each of the plurality of raspberry-like particles has a particle size between 0.01 μ

M and 50 μ

m.

4. The light-extraction element as claimed in claim 1, wherein each of the plurality of raspberry-like particles has a particle size between 0.3 μ

m and 40 μ

m.

5. The light-extraction element as claimed in claim 1, wherein the ratio of the weight of the plurality of raspberry-like particles to the weight of the resin is between 1/10 and 10/1.

6. The light-extraction element as claimed in claim 1, wherein the resin comprises a thermoplastic resin, a thermo-curable resin, a light-curable resin, or combinations thereof.

7. The light-extraction element as claimed in claim 1, wherein the plurality of raspberry-like particles are formed of an organic material, comprising polystyrene, polymethyl methacrylate, polydivinylbenzene, polyethylene glycol dimethacrylate, polytrimethylolpropane trimethacrylate, or copolymers thereof, polycarbonate, polyethylene, or combinations thereof.

8. The light-extraction element as claimed in claim 1, wherein the plurality of raspberry-like particles are formed of an inorganic material, comprising silicone resin, calcium carbonate, silicon dioxide, titanium dioxide, or combinations thereof.

9. The light-extraction element as claimed in claim 1, wherein the resin covers the plurality of raspberry-like particles and forms a flat top surface.

10. The light-extraction element as claimed in claim 1, wherein the resin covers the plurality of raspberry-like particles and forms an irregular top surface.

11. The light-extraction element as claimed in claim 1, further comprising a substrate, and the light-diffusion layer is disposed on the substrate.

12. The light-extraction element as claimed in claim 11, further comprising an adhesive layer which is disposed on an opposite surface of the substrate relative to the light-diffusion layer.

13. The light-extraction element as claimed in claim 12, wherein the adhesive layer comprises a transparent glue including polypropylene, a thermo-curable glue, or an ultraviolet light-curable glue.

14. The light-extraction element as claimed in claim 13, further comprising an additive including at least one non-ionic dispersant, at least one surfactant, or combinations thereof.

15. The light-extraction element as claimed in claim 14, wherein the ratio of the additive is 0.005-15 wt % based on the weight of the plurality of raspberry-like particles.

16. The light-extraction element as claimed in claim 14, wherein the ratio of the additive is 0.1-10 wt % based on the weight of the plurality of raspberry-like particles.

17. A light-emitting device, comprising:

a pair of electrodes composed of an anode and a cathode;

an organic light-emitting unit disposed between the pair of electrodes, wherein the organic light-emitting unit comprises a light-emitting layer; and

a light-extraction element as claimed in claim 1, which is disposed on a light-emitting surface of the light-emitting device.

18. The light-emitting device as claimed in claim 17, wherein the organic light-emitting unit further comprises:

a hole injection layer disposed on the anode;

a hole transport layer disposed on the hole injection layer;

an electron transport layer disposed on the hole transport layer; and

an electron injection layer disposed on the electron transport layer and under the cathode.