LED DEVICE HAVING A TILTED PEAK EMISSION AND AN LED DISPLAY INCLUDING SUCH DEVICES

• US 20120119230A1
• Filed: 06/15/2011
• Published: 05/17/2012
• Est. Priority Date: 04/24/2006
• Status: Active Grant

• Current Assignee: Cree Huizhou Solid State Lighting Company Limited (Smart Global Holdings Incorporated)
• Original Assignee: Cree Huizhou Solid State Lighting Company Limited (Smart Global Holdings Incorporated)
• Inventors: Lau, Yue Kwong, Fei, Xiang, Liu, Hao, Emerson, David Todd, CHAN, Chi Keung, Zhang, Zhi Kuan, Sheng, Ju Zuo
• Granted Patent: US 8,487,326 B2
• Time in Patent Office: Days
• US Class Current: 257/88
• CPC Class Codes: G02B 6/0023 provided by one optical element, or plurality thereof, placed between the light guide and the light source, or around the light source
• CPC Class Codes: G02B 6/0068 Arrangements of plural sources, e.g. multi-colour light sources
• CPC Class Codes: G02B 6/0073 Light emitting diode [LED]
• 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 33/54 having a particular shape
• CPC Class Codes: H01L 33/60 Reflective elements
• CPC Class Codes: H01L 33/62 Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls

Abstract

An LED package and a lead frame include a reflector cup having a bottom surface with an LED asymmetrically positioned on the bottom surface and a wall surface inclined relative to the bottom surface and defining an opening at an upper end thereof. The bottom surface of the reflector cup has a first axial dimension along a first axis and a second axial dimension along a second axis, orthogonal to the first axis. A display having an asymmetrical FFP and asymmetrical screen curve includes an array of the LED modules including a plurality of LED packages. At least some of the LED packages include a dome-shaped lens asymmetrically positioned with respect to a geometric center of the bottom surface of the reflector cup.

Claims

1. A light emitting diode (LED) package comprising:

a reflector cup having a bottom surface and a wall surface inclined relative to the bottom surface and defining an opening at an upper end thereof; and

an LED mounted on the bottom surface,

wherein the bottom surface has a first axial dimension about 0.91 mm to about 1.1 mm along a first axis and a second axial dimension of about 0.66 mm to about 0.91 mm along a second axis orthogonal to the first axis.

2. The LED package of claim 1, wherein the first axial dimension is about 0.2 mm to about 0.4 mm longer than the second axial dimension.

3. The LED package of claim 1, wherein an area of the bottom surface is greater than an area of a bottom surface of the LED and less than an area of the opening.

4. The LED package of claim 1, wherein the first axial dimension is about 0.95 mm to about 1.05 mm.

5. The LED package of claim 1, wherein the second axial dimension is about 0.75 mm to about 0.85 mm.

6. The LED package of claim 1, wherein the wall surface has a height about 0.2 mm to about 0.3 mm.

7. The LED package of claim 1, wherein the LED is displaced away from a crossing point of a first and second axis.

8. The LED package of claim 1, wherein a crossing point of the first and second axis is asymmetrically positioned with respect to a geometric center of the of the bottom surface.

9. The LED package of claim 1, wherein a crossing point of the first and second axis coincides with a geometric center of the bottom surface.

10. The LED package of claim 1, wherein a geometric center of the opening is displaced away from a crossing point of the first and second axis.

11. The LED package of claim 1, wherein a geometric center of the opening coincides with a crossing point of the first and second axis.

12. The LED package of claim 1, wherein a wall extending away from the wall surface has non-uniform thickness.

13. The LED package of claim 12, wherein a degree of inclination of the wall surface relative to the bottom surface continually varies such that the wall surface has a steep portion and a shallow portion.

14. The LED package of claim 13, wherein the shallow portion is inclined at an angle of about 40°

to about 50°

relative to the bottom surface, and the steep portion is inclined at an angle of about 50°

to about 85°

relative to the bottom surface.

15. The LED package of claim 2, wherein the ratio of the first axial dimension to the second axial dimension is about 5:

4.

16. The LED package of claim 1, further comprising a dome-shaped lens asymmetrically positioned with respect to a geometric center of the bottom surface and that covers the reflector cup.

17. The LED package of claim 16, wherein the lens has an asymmetric cross-section having a first dimension of about 3.5 mm to about 4.5 mm and a second dimension orthogonal to the first dimension of about 2.5 to about 3.5 mm.

18. The LED package of claim 17, wherein the lens has a profile height of about 5.3 mm to about 7.3 mm.

19. The LED package of claim 16, wherein the lens has rounded upper surface having a geometric center that is displaced about 0.2 mm to about 0.4 mm away from the geometric center with respect to a bottom cross-section of the lens.

20. The LED package of claim 16, wherein LED package generates a peak luminous intensity of about 3000 mcd and has a working current less than about 20 mA.

21. A display comprising:

a substrate carrying an array of light emitting diode (LED) packages arranged in vertical columns and horizontal rows;

at least one of the LED packages comprising a lead frame having a reflector cup, the reflector cup having a bottom surface and a wall surface inclined relative to the bottom surface and defining an opening at an upper end thereof;

an LED mounted on the bottom surface, wherein the bottom surface has a first axial dimension about 0.91 mm to about 1.1 mm along a first axis and a second axial dimension of about 0.66 mm to about 0.91 mm along a second axis orthogonal to the first axis; and

signal processing and LED drive circuitry electrically connected to selectively energize the array of LED packages for producing visual images on the display.

22. The display of claim 21, wherein an area of the bottom surface is greater than an area of a bottom surface of the LED and less than an area of the opening.

23. The display of claim 22, wherein a ratio of the first axial dimension to the second axial dimension ranges from about 1:

1 to about 11;

7.

24. The display of claim 21, wherein the first axial dimension is about 0.2 mm to about 0.4 mm longer than the second axial dimension.

25. The display of claim 24, wherein the display has an asymmetrical far field pattern with a peak luminous intensity below a horizontal center axis of the display.

26. The display of claim 21, wherein the LED is mounted away from a crossing point of the first and second axis.

27. The display of claim 26, wherein the bottom surface is asymmetrical about the first axis.

28. The display of claim 27, wherein the bottom surface is symmetrical about the second axis.

29. The display of claim 21, wherein the first axial dimension is about 0.95 mm to about 1.05 mm.

30. The display of claim 21, wherein the second axial dimension is about 0.75 mm to about 0.85 mm.

31. A lead frame comprising:

a reflector cup having a bottom surface and a wall surface inclined relative to the bottom surface and defining an opening at an upper end thereof,

wherein the bottom surface has a first axial dimension about 0.91 mm to about 1.1 mm along a first axis and a second axial dimension of about 72% to about 100% of the first axial dimension along a second axis orthogonal to the first axis.

32. The lead frame of claim 31, wherein the first axial dimension is about 0.95 mm to about 1.05 mm.

33. The lead frame of claim 31, wherein the second axial dimension is about 0.75 mm to about 0.85 mm.

34. The lead frame of claim 31, wherein the reflector cup has a depth about 0.2 mm to about 0.3 mm.

35. The lead frame of claim 31, wherein a wall extending from the wall surface has non-uniform thickness.

36. The lead frame of claim 31, wherein the bottom surface has a curved border portion and a straight border portion.

37. The lead frame of claim 36, wherein the curved border portion is longer than the straight border portion.

38. The lead frame of claim 36, wherein second axial dimension is about 80% of the first axial dimension.

39. A light emitting diode (LED) package comprising:

a reflector cup having a bottom surface and a wall surface inclined relative to the bottom surface and defining an opening at an upper end thereof; and

an LED mounted on the bottom surface,

wherein the bottom surface has a first axial dimension along a first axis and a second axial dimension along a second axis orthogonal to the first axis, the bottom surface has a curved border portion and a straight border portion, the curved border portion has a length greater than half of a perimeter of the bottom surface.

40. The LED package of claim 39, wherein the straight border portion has a length less than the first axial dimension.

41. A light emitting diode (LED) package comprising:

a reflector cup having a bottom surface and a wall surface inclined relative to the bottom surface and defining an opening at an upper end thereof; and

an LED mounted on the bottom surface,

wherein the bottom surface has a first axial dimension of less than about 0.89 mm and a second axial dimension of less than about 0.64 mm along a second axis orthogonal to the first axis.

42. The LED package of claim 41, wherein the wall surface has a height less than about 0.25 mm.

43. The LED package of claim 42, wherein the height is less than about 0.2 mm.

44. The LED package of claim 42, wherein the height is less than about 0.15 mm.

45. The LED package of claim 42, wherein the height is about 0.16 mm to about 0.24 mm.