LIGHT EMITTING DEVICE WITH DARK LAYER
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.
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.