Light transmitting substrate, method for manufacturing light transmitting substrate, organic LED element and method for manufacturing organic LED element

1. A translucent substrate comprising:

a translucent glass substrate;

a scattering layer formed on 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 on the scattering layer and having a third refractive index higher than the first refractive index,

wherein distribution of the scattering materials in the scattering layer decreases toward the translucent electrode in a vicinity of a surface at a translucent electrode side of the scattering layer.

2. The translucent electrode according to claim 1 , satisfying ρ 4 >ρ 3 , wherein ρ 3 is a density of the scattering materials at a distance x (x≦0.2 μm) from the surface of the scattering layer and ρ 4 is a density of the scattering materials at a distance x being 2 μm.

3. The translucent electrode according to claim 1 , wherein the distribution of the scattering materials in the scattering layer has in-plane uniformity.

4. The translucent electrode according to claim 3 , wherein difference between the first refractive index and the third refractive index is 0.2 or less.

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

6. The translucent electrode according to claim 5 , wherein a ratio (Ra/Rλa) between a roughness Ra of the waviness of the surface of the scattering layer and a wavelength Rλa of the waviness of the surface thereof is from 1.0×10 −3 to 3.0×10 −2 .

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

8. The translucent electrode according to claim 1 , wherein a content of the scattering materials in the scattering layer is at least 1 vol %.

9. The translucent electrode according to claim 1 , wherein the scattering materials are pores.

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

11. The translucent electrode according to claim 1 , wherein the number of the scattering materials per 1 mm 2 of the scattering layer is at least 1×10 4 .

12. The translucent electrode according to claim 1 , wherein the scattering layer contains 20 to 30 mol % of P 2 O 5 , 3 to 14 mol % of B 2 O 3 , 10 to 20 mol % of Li 2 O, Na 2 O and K 2 O in terms of total amount thereof, 10 to 20 mol % of Bi 2 O 3 , 3 to 15 mol % of TiO 2 , 10 to 20 mol % of Nb 2 O 5 and 5 to 15 mol % of WO 3 .

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

preparing a translucent glass substrate,

forming on the glass substrate a scattering layer comprising:

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

forming on the scattering layer a translucent electrode having a third refractive index higher than the first refractive index,

wherein the scattering layer forming step includes steps of:

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

firing the applied glass powder, and

wherein distribution of the scattering materials in the scattering layer decreases toward the translucent electrode in a vicinity of a surface at a translucent electrode side of the scattering layer.

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 40 to 60° C. higher than a 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 D 10 of 0.2 μm or more and D 90 of 5 μm or less.

16. An organic LED element comprising:

a translucent glass substrate;

a scattering layer formed on 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;

a translucent electrode formed on the scattering layer and having a third refractive index higher than the first refractive index;

an organic layer formed on the translucent electrode, and

a reflective electrode formed on the organic layer,

wherein distribution of the scattering materials in the scattering layer decreases toward the translucent electrode in a vicinity of a surface at a translucent electrode side of the scattering layer.

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

preparing a translucent glass substrate,

forming on the glass substrate a scattering layer comprising:

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;

forming on the scattering layer a translucent electrode having a third refractive index higher than the first refractive index;

forming an organic layer on the translucent electrode; and

forming a reflective electrode on the organic layer,

wherein distribution of the scattering materials in the scattering layer decreases toward the translucent electrode in a vicinity of a surface at a translucent electrode side of the scattering layer.