Granted Patent B2

US 7,952,270 · App. 11/995,385 · Granted May 31, 2011

Abstract

Claims (39)

1. An electroluminescent device comprising:

at least one electroluminescent light source with an electroluminescent layer for emitting a primary radiation with an emission characteristic around a mean emission direction, and

at least one light-converting element for converting at least part of the primary radiation into a secondary radiation, the at least one light-converting element having first, second and edge surfaces, a first spacing and a second larger spacing between the first and second surfaces, the first spacing is in a center of the at least one light-converting element and the second spacing is around its perimeter,

wherein a shape of the second and edge surfaces of the light-converting element is adapted to the emission characteristic of the electroluminescent light source so as to generate a defined correlated color temperature as a function of a viewing angle,

wherein the first surface faces toward the electroluminescent light source, the second surface faces away from the electroluminescent light source, and the edge surface is arranged between the first and second surface, and

wherein the edge surface is arranged at an acute angle to a plane normal of the electroluminescent layer of the electroluminescent light source.

2. The electroluminescent device as claimed in claim 1 , wherein the light-converting element is optically connected to the electroluminescent light source.

3. The electroluminescent device as claimed in claim 1 , wherein the light-converting element comprises a material selected from at least one of ceramic and a dimensionally stable matrix material with embedded light-converting particles.

4. The electroluminescent device as claimed in claim 3 , wherein the ceramic material has a density greater than 97% of the theoretical solid density.

5. The electroluminescent device as claimed in claim 3 , wherein the light-converting element reflects less than 20% of the primary radiation.

6. The electroluminescent device as claimed in claim 1 , wherein the shape of the light-converting element is selected from the group consisting of sheet-like shapes, disk-like shapes, bowl-like shapes.

7. The electroluminescent device as claimed in claim 6 , wherein the light-converting element protrudes beyond the electroluminescent layer by an excess length U LKE parallel to the electroluminescent layer of the electroluminescent light source.

8. The electroluminescent device as claimed in claim 1 , wherein the acute angle is between 20° and 70°.

9. The electroluminescent device as claimed in claim 1 , wherein at least one surface from the group consisting of first surface, second surface and edge surface has a refractive structure.

10. An electroluminescent device comprising:

at least one electroluminescent light source with an electroluminescent layer for emitting a primary radiation with an emission characteristic around a mean emission direction, and

at least one light-converting element for converting at least part of the primary radiation into a secondary radiation, the at least one light-converting element having first, second and edge surfaces, a first spacing and a second larger spacing between the first and second surfaces, the first spacing is in a center of the at least one light-converting element and the second spacing is around its perimeter,

wherein the electroluminescent layer protrudes beyond the light-converting element by an excess length U EL parallel to the first surface of the light-converting element.

11. An electroluminescent device comprising:

at least one electroluminescent light source with an electroluminescent layer for emitting a primary radiation with an emission characteristic around a mean emission direction, and

at least one light-converting element for converting at least part of the primary radiation into a secondary radiation, the at least one light-converting element having first, second and edge surfaces, a first spacing and a second larger spacing between the first and second surfaces, the first spacing is in a center of the at least one light-converting element and the second spacing is around its perimeter,

wherein a shape of the second and edge surfaces of the light-converting element is adapted to the emission characteristic of the electroluminescent light source so as to generate a defined correlated color temperature as a function of a viewing angle,

wherein the light-converting element protrudes beyond the electroluminescent layer by an excess length U LKE parallel to the electroluminescent layer of the electroluminescent light source, and

wherein the excess length U LKE is equal to or greater than the distance between the electroluminescent layer and the first surface of the light-converting element.

12. An electroluminescent device comprising:

at least one electroluminescent light source with an electroluminescent layer for emitting a primary radiation with an emission characteristic around a mean emission direction, and

at least one light-converting element for converting at least part of the primary radiation into a secondary radiation, the at least one light-converting element having first, second and edge surfaces, a first spacing and a second larger spacing between the first and second surfaces, the first spacing is in a center of the at least one light-converting element and the second spacing is around its perimeter,

wherein a shape of the second and edge surfaces of the light-converting element is adapted to the emission characteristic of the electroluminescent light source so as to generate a defined correlated color temperature as a function of a viewing angle,

wherein the first surface faces toward the electroluminescent light source, the second surface faces away from the electroluminescent light source, and the edge surface is arranged between the first and second surface, and

wherein the second spacing is less than or equal to four times the first spacing.

13. A method for producing an electroluminescent device having at least one electroluminescent light source with an electroluminescent layer for emitting a primary radiation with an emission characteristic around a mean emission direction, the method comprising acts of:

providing at least one light-converting element for converting at least part of the primary radiation into a secondary radiation, the at least one light-converting element having first, second and edge surfaces, a first spacing and a second larger spacing between the first and second surfaces, the first spacing is in a center of the at least one light-converting element and the second spacing is around its perimeter, wherein the first surface faces toward the electroluminescent light source, the second surface faces away from the electroluminescent light source, the edge surface is arranged between the first and second surface and is arranged at an acute angle to a plane normal of the first surface,

defining a desired correlated color temperature as a function of a viewing angle, and

adapting a shape of the second and edge surfaces of the light-converting element to the emission characteristic of the electroluminescent light source so as to generate a defined correlated color temperature as a function of the viewing angle.

14. An electroluminescent device comprising:

at least one electroluminescent light source with an electroluminescent layer for emitting a primary radiation with an emission characteristic around a mean emission direction, and

at least one light-converting element for converting at least part of the primary radiation into a secondary radiation, the at least one light-converting element having first, second and edge surfaces, a first spacing and a second larger spacing between the first and second surfaces, the first spacing is in a center of the at least one light-converting element and the second spacing is around its perimeter,

wherein the first surface faces toward the electroluminescent light source, the second surface faces away from the electroluminescent light source, the edge surface is arranged between the first and second surface, wherein the second spacing extends beyond the first spacing in a direction away from the electroluminescent light source, and

wherein a shape of the second and edge surfaces of the light-converting element is adapted to the emission characteristic of the electroluminescent light source so as to generate a defined correlated color temperature as a function of a viewing angle.

Assignments (6)