TRANSLUCENT SUBSTRATE, PROCESS FOR PRODUCING THE SAME, ORGANIC LED ELEMENT AND PROCESS FOR PRODUCING THE SAME

• US 20090153972A1
• Filed: 12/12/2008
• Published: 06/18/2009
• Est. Priority Date: 07/27/2007
• Status: Active Grant

• Current Assignee: AGC, Inc.
• Original Assignee: Asahi Glass Company, Limited (AGC, Inc.)
• Inventors: Ohkawa, Hiroyuki, Imakita, Kenji, Ishibashi, Nao, Hayashi, Kazutaka, NAKAMURA, Nobuhiro, Odaka, Hidefumi
• Granted Patent: US 8,018,140 B2
• Time in Patent Office: Days
• US Class Current: 359/599
• CPC Class Codes: C03C 17/36 at least one coating being a metal
• CPC Class Codes: C03C 17/3644 the metal being silver
• CPC Class Codes: C03C 17/3657 the multilayer coating having optical properties
• CPC Class Codes: C03C 2217/425 consisting of a porous layer
• CPC Class Codes: C03C 2217/45 Inorganic continuous phases
• CPC Class Codes: C03C 2217/948 Layers comprising indium tin oxide [ITO]
• CPC Class Codes: C03C 3/21 containing titanium, zirconium, vanadium, tungsten or molybdenum
• CPC Class Codes: C03C 8/08 containing phosphorus
• CPC Class Codes: H01L 2924/16152 Cap comprising a cavity for hosting the device, e.g. U-shaped cap
• CPC Class Codes: H05B 33/02 Details
• CPC Class Codes: H05B 33/10 Apparatus or processes specially adapted to the manufacture of electroluminescent light sources
• CPC Class Codes: H05B 33/22 characterised by the chemical or physical composition or the arrangement of auxiliary dielectric or reflective layers
• CPC Class Codes: H10K 50/854 comprising scattering means
• CPC Class Codes: H10K 59/877 comprising scattering means

Abstract

The present invention provides an organic LED element in which the extraction efficiency is improved up to 80% of emitted light. Further, the invention relates to an electrode-attached translucent substrate having a translucent substrate, a scattering layer formed over the glass substrate and containing a base material having a first refractive index for at least one wavelength of wavelengths of emitted light of an organic LED element and a plurality of scattering materials positioned in the base material and having a second refractive index different from that of the base material, and a translucent electrode formed over the scattering layer and having a third refractive index equal to or lower than the first refractive index, in which distribution of the scattering materials in the scattering layer decreases from the inside of the scattering layer toward the translucent electrode.

Claims

1. An electrode-attached translucent substrate comprising:

a translucent glass substrate;

a scattering layer formed over the glass substrate and comprising a glass which contains;

a base material having a first refractive index for at least one wavelength of light to be transmitted; and

a plurality of scattering materials dispersed in the base material and having a second refractive index different from that of the base material; and

a translucent electrode formed over the scattering layer and having a third refractive index equal to or lower than the first refractive index,

wherein distribution of the scattering materials in the scattering layer decreases from the inside of the scattering layer toward the translucent electrode.

2. The translucent substrate according to claim 1, satisfying ρ

₄>

ρ

₃, wherein ρ

₃ is a density of the scattering material at a distance x (x≦

0.2 μ

m) from a surface of the scattering layer and ρ

₄ is a density of the scattering material at a distance x being 2 μ

m.

3. The translucent substrate according to claim 1, wherein a surface of the scattering layer has waviness constituting a curved surface.

4. The translucent substrate according to claim 3, wherein the ratio Ra/Rλ

a of a waviness roughness Ra of the surface of the scattering layer to a wavelength Rλ

a of the waviness of the surface is from 1.0×

10<sup>−

3</sup> to 3.0×

10<sup>−

2</sup>.

5. The translucent substrate according to claim 1, wherein a surface roughness Ra of the surface of the scattering layer is 30 nm or less.

6. The translucent substrate according to claim 1, wherein the content of the scattering material in the scattering layer is at least 1 vol %.

7. The translucent substrate according to claim 1, wherein the scattering materials are pores.

8. The translucent substrate according to claim 1, wherein the scattering materials are material particles having a composition different from that of the base layer.

9. The translucent substrate according to claim 1, wherein the scattering materials are precipitated crystals of a glass constituting the base layer.

10. The translucent substrate according to claim 1, wherein the number of the scattering materials per 1 mm² of the scattering layer is at least 1×

10⁴.

11. The translucent substrate according to claim 1, wherein the scattering layer has an average thermal expansion coefficient over the range of 100°

C. to 400°

C. of 70×

10<sup>−

7</sup>(°

C.<sup>−

1</sup>) to 95×

10<sup>−

7</sup>(°

C.<sup>−

1</sup>), and a glass transition temperature of 450°

C. to 550°

C.

12. The translucent substrate according to claim 1, wherein the scattering layer contains 20 to 30 mol % of P₂O₅, 3 to 14 mol % of B₂O₃, 10 to 20 mol % of Li₂O, Na₂O and K₂O in terms of total amount thereof, 10 to 20 mol % of Bi₂O₃, 3 to 15 mol % of TiO₂, 10 to 20 mol % of Nb₂O₅ and 5 to 15 mol % of WO₃.

17. The translucent substrate according to claim 1, having a wavelength of light to be transmitted being equal to a wavelength of emitted light of an organic LED element.

18. An organic LED element comprising an organic layer formed over the translucent electrode layer of the translucent substrate according to claim 17 and a reflective electrode formed over the organic layer.

13. A process for producing a translucent substrate comprising the steps of:

preparing a translucent glass substrate,

forming over the glass substrate a scattering layer comprising;

a base material having a first refractive index; and

a plurality of scattering materials dispersed in the base material and having a second refractive index different from that of the base material, and

forming a translucent electrode over the scattering layer,

wherein the scattering layer forming step includes the steps of;

applying a coating material containing a glass powder onto the glass substrate, and

firing the applied glass powder, and

wherein the intralayer distribution of the scattering materials in the scattering layer decreases from the inside of the scattering layer toward the outermost surface thereof.

14. The process for producing a translucent substrate according to claim 13, wherein the firing step includes a step of firing the glass powder at a temperature which is 60 to 100°

C. higher than the glass transition temperature of the applied glass material.

15. The process for producing a translucent substrate according to claim 13, wherein the applying step includes a step of applying the glass powder having a particle size D₁₀ of 0.2 μ

m or more and D₉₀ of 5 μ

m or less.

16. A process for producing an organic LED element comprising:

the process for producing a translucent substrate according to claim 13;

a step of forming a layer having a light emitting function over the translucent layer as a first electrode; and

a step of forming a second electrode over the layer having a light emitting function.

19. The process for producing a translucent substrate according to claim 13, wherein the base material and the scattering materials constituting the scattering layer are a base material having a first refractive index for at least one wavelength of wavelengths of emitted light of an organic LED element and a plurality of scattering materials positioned in the base material and having a second refractive index different from that of the base material, respectively, and

the translucent electrode layer has a third refractive index equal to or lower than the first refractive index at the wavelength.

20. A process for producing an organic LED element comprising the steps of:

forming an organic layer over the translucent electrode of the translucent substrate according to claim 19, and

forming a reflective electrode over the organic layer.