Multiple die LED and lens optical system

• US 20070034890A1
• Filed: 08/10/2005
• Published: 02/15/2007
• Est. Priority Date: 08/10/2005
• Status: Active Grant

• Current Assignee: Lumileds LLC (Apollo Global Management, Inc.)
• Original Assignee: Lumileds Lighting US LLC (Apollo Global Management, Inc.)
• Inventors: Quan, Xina, Wang, Nanze, Daschner, Walter
• Granted Patent: US 8,163,580 B2
• Time in Patent Office: Days
• US Class Current: 257/100
• CPC Class Codes: G03B 15/03 Combinations of cameras with lighting apparatus; Flash units
• CPC Class Codes: G03B 2215/0503 Built-in units
• CPC Class Codes: G03B 2215/0567 Solid-state light source, e.g. LED, laser
• CPC Class Codes: G03B 2215/0571 With second light source
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 33/58 Optical field-shaping elements
• CPC Class Codes: H04N 23/56 provided with illuminating means

Abstract

A light emitting device includes a number of light emitting diode dies (LEDs) mounted on a shared submount and covered with a single lens element that includes a corresponding number of lens elements. The LEDs are separated from each other by a distance that is sufficient for lens element to include separate lens elements for each LED. The separation of the LEDs and lens elements may be configured to produce a desired amount of light on a target at a predefined distance. In one embodiment, the lens elements are approximately flat type lens elements, such as Fresnel, TIR, diffractive lens, photonic crystal type lenses, prism, or reflective lens.

Claims

1. An apparatus comprising:

an approximately planar submount;

a plurality of light emitting diode dies mounted on the submount, the plurality of light emitting diode dies being separated from each other; and

a lens system positioned over the plurality of light emitting diode dies, the lens system having an individual lens element for each of the plurality of light emitting diode dies, the individual lens elements being integrally formed, each of the individual lens elements being aligned with a respective light emitting diode die.

2. The apparatus of claim 1, wherein the individual lens elements are separated from each other, the separation between the light emitting diode dies, the separation between the individual lens elements, and the alignment of the individual lens elements with a respective light emitting diode die are configured to produce a desired light distribution on target at a predefined distance.

3. The apparatus of claim 2, wherein the plurality of light emitting diode dies are separated from each other by a distance greater than 130% center to center of the size of the light emitting diode dies.

4. The apparatus of claim 3, wherein the individual lens elements are separated from each other by a distance that is equal to or greater than the separation of the plurality of light emitting diode dies.

5. The apparatus of claim 1, wherein the individual lens elements are substantially flat.

6. The apparatus of claim 5, wherein each of the individual lens elements are at least one of a Fresnel lens, Total Internal Reflection type lens, a diffractive lens, photonic crystal type lens, a prism and a reflective lens.

7. The apparatus of claim 1, wherein the lens system is formed by at least one of injection molding, casting, and transfer molding.

8. The apparatus of claim 1, further comprising an electrostatic discharge circuit mounted on the submount.

9. The apparatus of claim 8, wherein the electrostatic discharge circuit is mounted between at least two of the plurality of light emitting diode dies.

10. The apparatus of claim 1, wherein the submount comprises at least one metal trace formed on the surface of or within the submount, wherein one of the plurality of light emitting diode dies is electrically connected to the metal trace.

11. The apparatus of claim 1, wherein at least one of the light emitting diode dies is an inverted type having all of a plurality of electrical contacts on a bottom surface of the light emitting diode die wherein the plurality of electrical contacts are between the submount and the bottom surface of the light emitting diode die.

12. The apparatus of claim 1, further comprising a cell phone, wherein the submount, the plurality of light emitting diodes and the lens system are mounted to the cell phone.

13. A method comprising:

providing a first substrate comprising a plurality of submounts;

mounting a plurality of light emitting diode dies on each of the plurality of submounts;

providing a second substrate comprising an array of lens systems, each lens system in the array comprising individual lens elements;

mounting the second substrate over the first substrate to form a plurality of devices, wherein the second substrate is positioned with respect to the first substrate so that each individual lens element is aligned with an underlying light emitting diode die; and

separating said plurality of devices.

14. The method of claim 13, wherein the plurality of light emitting diode dies are separated from each other by a distance greater than 130% center to center of the size of the light emitting diode dies.

15. The method of claim 14, wherein the individual lens elements are separated from each other, the separation between the light emitting diode dies, the separation between the individual lens elements, and the alignment of the individual lens elements with a respective light emitting diode die are configured to produce a desired light distribution on target at a predefined distance.

16. The method of claim 13, wherein each individual lens element is substantially flat.

17. The method of claim 16, wherein each of the individual lens elements are at least one of a Fresnel lens, Total Internal Reflection type lens, a diffractive lens, photonic crystal type lens, a prism and a reflective lens.

18. The method of claim 13, wherein second substrate having an array of lens systems is formed by at least one of injection molding, casting, and transfer molding.

19. The method of claim 13, wherein each of the plurality of submounts comprises at least one metal trace formed on the surface of or within the submount, wherein one of the plurality of light emitting diode dies is electrically connected to the metal trace.

20. The method of claim 19, wherein at least one of the light emitting diode dies is an inverted type having all of a plurality of electrical contacts on a bottom surface of the light emitting diode die wherein the plurality of electrical contacts are between the submount and the bottom surface of the light emitting diode die.

21. The method of claim 13, further comprising providing an encapsulant between the first substrate and the second substrate.

22. The method of claim 21, wherein the encapsulant bonds the first substrate to the second substrate.

23. A method comprising:

providing an approximately planar submount;

positioning and mounting a plurality of light emitting diode dies on the submount, the plurality of light emitting diode dies being positioned to be separated from each other;

providing a lens system comprising integrally formed individual lens element, wherein there is an individual lens element for each of the plurality of light emitting diode dies; and

optically coupling the submount with the plurality of mounted light emitting diode dies to the lens system so that each of the individual lens elements is aligned with a corresponding light emitting diode die.

24. The method of claim 23, wherein the plurality of light emitting diode dies are positioned to be separated from each other by a distance greater than 130% center to center of the size of the light emitting diode dies.

25. The method of claim 24, wherein the individual lens elements are separated from each other, the separation between the light emitting diode dies, the separation between the individual lens elements, and the alignment of the individual lens elements with a respective light emitting diode die are configured to produce a desired light distribution on target at a predefined distance.

26. The method of claim 23, wherein each individual lens element is substantially flat.

27. The method of claim 23, wherein each of the individual lens elements are at least one of a Fresnel lens, Total Internal Reflection type lens, a diffractive lens, photonic crystal type lens, a prism and a reflective lens.

28. The method of claim 23, wherein the submounts comprises at least one metal trace formed on the surface of or within the submount, wherein one of the plurality of light emitting diode dies is electrically connected to the metal trace.

29. The method of claim 28, wherein at least one of the light emitting diode dies is an inverted type having all of a plurality of electrical contacts on a bottom surface of the light emitting diode die wherein the plurality of electrical contacts are between the submount and the bottom surface of the light emitting diode die.

30. The method of claim 23, further comprising providing an encapsulant between the submount with a plurality of light emitting diode dies and the lens system.

31. The method of claim 30, wherein the encapsulant bonds the lens system to the submount with a plurality of light emitting diode dies.