Flip-chip side emitting LED with top reflector, peripheral wavelength conversion element, and optical element between light emitting element and lightguide element
View Patent ↗Application of a wavelength conversion element is substantially independent of the fabrication of a side-emitting light emitting device. In an example embodiment, the wavelength conversion element is situated around the periphery of a non-wavelength converting lightguide that is situated above the light emitting surface. One or more specular and/or diffusing reflectors are used to direct the light in the lightguide toward the wavelength conversion element at the periphery. In another embodiment, an interference filter may be used to provide predominantly side-emitted light at interfaces between the elements of the light emitting device.
1. A side-emitting device, comprising:
a light emitting element having a light emitting surface that emits light in an upward direction,
a non-wavelength-converting lightguide element that is situated above the light emitting surface and receives the light emitted from the light emitting element,
top reflectors situated above the lightguide element that serve to direct the light in the lightguide element to exit from one or more first side surfaces of the lightguide element, the top reflectors comprising a specular reflector situated above the lightguide element and a diffusing reflector situated above the specular reflector, and
one or more wavelength conversion elements situated at the one or more first side surfaces of the lightguide element, which receive and convert some or all of the light emitted by the lightguide element to a different wavelength.
2. The device of claim 1 , wherein the lightguide element comprises a growth substrate upon which the light emitting element was formed.
3. The device of claim 1 , wherein the lightguide element comprises one of sapphire, glass, and transparent ceramic.
4. The device of claim 1 , wherein the light emitting element is configured to provide a light output pattern from the light emitting surface with a luminance in at least one direction that is greater than the luminance in a direction normal to the light emitting surface.
5. The device of claim 1 , further comprising one or more side reflectors situated at one or more second side surfaces of the lightguide element so the light emitted by the lightguide element exits only from the one or more first side surfaces of the lightguide element.
6. A side-emitting device, comprising:
a light emitting element having a light emitting surface that emits light in an upward direction,
a first optical element situated above the light emitting element,
an interface between the light emitting element and the first optical element,
one or more reflective elements situated on sidewalls of the first optical element,
a second optical element situated above the first optical element, the second optical element having a same or lower index of refraction than the first optical element, the second optical element comprising a non-wavelength-converting lightguide element that receives the light emitted from the light emitting element through the first optical element,
one or more top reflectors situated above the lightguide element that serve to direct the light in the lightguide element to exit from one or more side surfaces of the lightguide element, and
one or more wavelength conversion elements situated on the one or more side surfaces of the lightguide element, which receive and convert some or all of the light emitted by the lightguide element to a different wavelength.
7. The device of claim 6 , wherein the first optical element comprises a growth substrate upon which the light emitting element was formed.
8. The device of claim 6 , wherein the first optical element comprises one of sapphire, glass, and transparent ceramic.
9. The device of claim 6 , wherein the lightguide element comprises one of sapphire, glass, and transparent ceramic.
10. The device of claim 6 , wherein the light emitting element is configured to provide a light output pattern with a luminance in at least one direction that is greater than the luminance in a direction normal to the light emitting surface.
11. The device of claim 6 , including an interference filter situated between the first and the second optical elements, the interference filter providing a light output pattern from a surface of the interference filter with a luminance in at least one direction that is greater than the luminance in a direction normal to the light emitting surface.
12. The device of claim 6 , wherein the one or more top reflectors comprise:
a specular reflector that is situated above the lightguide element, and
a diffusing reflector that is situated above the specular reflector.
13. A method of forming a side-emitting device, comprising:
providing a light emitting element having a light emitting surface that emits light in an upward direction,
providing a non-wavelength-converting lightguide element that is situated above the light emitting surface,
providing top reflectors situated above the lightguide element that serve to direct light in the lightguide element to exit one or more first side surfaces of the lightguide element, the top reflectors comprising a specular reflector situated above the lightguide element and a diffusing reflector is situated above the specular reflector, and
providing one or more wavelength conversion elements situated at the one or more first side surfaces of the lightguide element to receive and convert some or all of the light emitted by the lightguide element to a different wavelength.
14. The method of claim 13 , wherein providing the lightguide element and the light emitting element includes providing a growth substrate upon which the light emitting element is formed.
15. The method of claim 13 , further comprising providing one or more side reflectors situated at one or more second side surfaces of the lightguide element so the light emitted by the lightguide element exits only from the one or more first side surfaces of the lightguide element.
16. A method of forming a side-emitting device comprising:
providing a light emitting element having a light emitting surface that emits light in an upward direction,
providing a first optical element situated above the light emitting element, an interface existing between the light emitting element and the first optical element,
providing one or more reflective elements situated on sidewalls of the first optical element,
providing a second optical element situated above the first optical element, the second optical element having a same or lower index of refraction than the first optical element, the second optical element comprising a non-wavelength-converting lightguide element that receives the light emitted from the light emitting element through the first optical element,
providing one or more top reflectors situated above the lightguide element that serve to direct light in the lightguide element to exit one or more side surfaces of the lightguide element, and
providing one or more wavelength conversion elements situated on the one or more side surfaces of the lightguide element to receive and convert some or all of the light emitted by the lightguide element to a different wavelength.
17. The method of claim 16 , including providing an interference filter situated between the first and the second optical elements, the interference filter providing a light output pattern from a surface of the interference filter with a luminance in at least one direction that is greater than the luminance in a direction normal to the light emitting surface.
18. The method of claim 16 , wherein said providing one or more top reflectors comprises:
providing a specular reflector that is situated above the lightguide element, and
providing a diffusing reflector that is situated above the specular reflector.
19. The method of claim 16 , wherein the first optical element comprises a growth substrate upon which the light emitting element was formed.
20. The method of claim 16 , wherein the first optical element comprises one of sapphire, glass, and transparent ceramic.
21. The method of claim 16 , wherein the lightguide element comprises one of sapphire, glass, and transparent ceramic.
22. The method of claim 16 , wherein the light emitting element is configured to provide a light output pattern with a luminance in at least one direction that is greater than the luminance in a direction normal to the light emitting surface.