LIGHT EMITTING DEVICE WITH DARK LAYER

• US 20130307013A1
• Filed: 05/15/2012
• Published: 11/21/2013
• Est. Priority Date: 05/15/2012
• Status: Abandoned Application

• Current Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Original Assignee: Avago Technologies ECBU IP Singapore Pte Limited (Broadcom, Inc.)
• Inventors: Chan, Bit Tie, Ng, Keat Chuan, Ong, Kiam Soon
• Application Number:
  US13/472,285
• Publication Number:
  US 20130307013A1
• Time in Patent Office: Days
• US Class Current: 257/99
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 33/44 characterised by the coatings, e.g. passivation layer or anti-reflective coating
• CPC Class Codes: H01L 33/486 adapted for surface mounting
• CPC Class Codes: H01L 33/58 Optical field-shaping elements

Abstract

A light-emitting device having a plurality of leads, a body, a light source die, a dark layer, and a substantially transparent encapsulant is disclosed. The dark layer absorbs a substantial portion of ambient light. The light source die may be a top emitting die. The light-emitting devices may be suitable for applications such as a large scale electronic display where each pixel is represented by each light-emitting device. The dark layer may contribute towards high contrast ratio by absorbing substantial amount of ambient light falling thereon.

Claims

1. A light-emitting device, comprising

a body having a base portion;

a plurality of conductors, a portion of the conductors being located on the base portion;

at least one light source die attached on a portion of one of the conductors adapted to accommodate the light source die; and

a dark layer characterized by a dark visual appearance arranged adjacent to the light source die on the base portion for absorbing light falling thereon.

2. The light-emitting device of claim 1, wherein the dark layer substantially occludes the portion of the plurality of conductors located on the base portion.

3. The light-emitting device of claim 1, wherein the dark layer is configured to occlude the base portion, substantially inhibiting the base portion from reflecting light.

4. The light-emitting device of claim 1, wherein the dark layer comprises black pigment.

5. The light-emitting device of claim 1, wherein the dark visual appearance of the dark layer is substantially black.

6. The light-emitting device of claim 1, wherein approximately ninety percent of light falling onto the dark layer is absorbed.

7. The light-emitting device of claim 1, wherein the dark layer is in direct contact with the light source die.

8. The light-emitting device of claim 1, wherein the dark layer has a thickness that is approximately less than forty percent the height of the light source die.

9. The light-emitting device of claim 1 further comprising an encapsulant substantially encapsulating the dark layer, the light source die and at least part of the base portion.

10. The light-emitting device of claim 1, wherein the at least one light source die is a top emitting die configured to emit light substantially in a direction approximately perpendicular to the base portion.

11. The light-emitting device of claim 1, wherein the body is substantially dark but lighter than the dark visual appearance of the dark layer.

12. The light-emitting device of claim 1, wherein the body comprises a printed circuit board.

13. The light-emitting device of claim 1, wherein the body further comprises at least a sidewall having an inner surface arranged substantially perpendicular to the base portion.

14. The light-emitting device of claim 13, wherein the at least one sidewall is substantially non-reflective.

15. The light-emitting device of claim 1, wherein the light-emitting device is adapted to form a portion of an electronic display.

16. A light source, comprising:

a body having a surface and at least one sidewall;

a cavity defined by the surface and the at least one sidewall;

a light source die configured to emit light, the light source die being disposed within the cavity on the surface of the body;

an aperture directly connecting the cavity externally for light emission;

a dark layer characterized by a dark visual appearance and arranged within the cavity adjacent to the light source die for absorbing light; and

an encapsulant substantially encapsulating the light source die, the surface and the dark layer within the cavity.

17. The light source of claim 16, wherein the at least one cavity sidewall comprises an inner surface arranged substantially perpendicular to the surface.

18. The light source of claim 16 further comprising a plurality of leads arranged with a portion of the leads disposed on the surface, wherein the dark layer is arranged to occlude light from falling on the portion of the leads disposed on the surface.

19. The light source of claim 16, wherein the dark layer is in direct contact with the light source die.

20. An electronic display system, comprising:

a substrate;

a plurality of light-emitting devices attached on the substrate;

a flat surface located on each of the light-emitting devices;

at least one light source die located on the flat surface; and

a dark layer adjacent to the light source die covering the flat surface to occlude the flat surface from light.