Light emitting device, light emitting diode package, backlight unit, and liquid crystal display
A light emitting diode including a circuit board, at least one light emitting diode chip disposed on the circuit board, the light emitting diode chip including a substrate, a light emitting structure disposed under the substrate and including a first conductivity type semiconductor layer and a second conductivity type semiconductor layer, a transparent electrode layer disposed on a lower surface of the light emitting structure, first and second electrode pads electrically connected to the first and second conductivity type semiconductor layers, respectively, a reflective layer covering at least part of the lower surface of the light emitting structure, a reflective member covering an upper surface of the light emitting diode chip and including at least one of a distributed Bragg reflector (DBR) and metal, and a light transmitting resin surrounding the light emitting diode chip and the reflective member on the circuit board.
1. A light emitting diode comprising:
a circuit board;
at least one light emitting diode chip disposed on the circuit board, the light emitting diode chip comprising:
a substrate;
a light emitting structure disposed under the substrate and including a first conductivity type semiconductor layer and a second conductivity type semiconductor layer;
a transparent electrode layer disposed on a lower surface of the light emitting structure;
a first electrode pad electrically connected to the first conductivity type semiconductor layer of the light emitting structure; and
a second electrode pad electrically connected to the second conductivity type semiconductor layer of the light emitting structure;
a reflective member disposed on an upper surface of the light emitting diode chip;
a light transmitting resin contacting the light emitting diode chip and the reflective member on the circuit board; and
a dam disposed on the circuit board to surround the light emitting diode chip while being spaced apart from a side surface of the light emitting diode chip,
wherein the dam has a portion having a curved shape.
2. The light emitting diode according to claim 1 , wherein the circuit board includes at least one of a printed circuit board (PCB), a metal PCB, and a flexible printed circuit board (FPCB).
3. The light emitting diode according to claim 1 , wherein the light transmitting resin comprises a transparent epoxy resin or a transparent silicone resin.
4. The light emitting diode according to claim 3 , wherein the dam surrounds the light emitting diode chip in substantially a rectangular shape.
5. The light emitting diode according to claim 3 , wherein the dam surrounds the light emitting diode chip in substantially a circular shape.
6. The light emitting diode according to claim 1 , wherein the substrate comprises a transparent substrate.
7. The light emitting diode according to claim 1 , wherein the transparent electrode layer is disposed on a lower surface of the second conductivity type semiconductor layer.
8. The light emitting diode according to claim 7 , wherein the transparent electrode layer comprises ITO or ZnO.
9. The light emitting diode according to claim 1 , further comprising a reflective layer comprising a single layer or multilayer DBR.
10. The light emitting diode according to claim 1 , further comprising a reflective layer comprising an insulating layer and a metal layer.
11. The light emitting diode according to claim 1 , wherein the reflective member comprises the DBR, the DBR having a multilayer structure including at least two layers of SiO 2 , TiO 2 , SiN, and TiN stacked one above another.
12. The light emitting diode according to claim 1 , wherein the reflective member comprises at least one of Ag and Al.
13. The light emitting diode according to claim 1 , wherein the dam includes a material configured to block light emitted from the light emitting diode chip.
14. The light emitting diode according to claim 13 , wherein the dam comprises a silicone resin.
15. The light emitting diode according to claim 1 , wherein the dam has a height to form an angle (θ) from an optical axis of a light emitting surface to a top surface of the dam to be greater than a peak beam angle of the light emitting diode chip.
16. A backlight unit comprising:
a light emitting diode comprising:
a circuit board;
at least one light emitting diode chip disposed on the circuit board, the light emitting diode chip comprising:
a substrate;
a light emitting structure disposed under the substrate and including a first conductivity type semiconductor layer and a second conductivity type semiconductor layer;
a transparent electrode layer disposed on a lower surface of the light emitting structure;
a first electrode pad electrically connected to the first conductivity type semiconductor layer of the light emitting structure; and
a second electrode pad electrically connected to the second conductivity type semiconductor layer of the light emitting structure;
a reflective layer covering at least part of the lower surface of the light emitting structure; and
a light transmitting resin surrounding the light emitting diode chip on the circuit board; and
an optical member disposed on the light emitting diode and overlapping the light emitting diode in a thickness direction of the light emitting diode.
17. The backlight unit according to claim 16 , wherein the optical member comprises at least one of a diffusion sheet, a quantum dot (QD) sheet, a reflective film, a phosphor sheet, a prism sheet, a brightness enhancement film (BEF), and a dual brightness enhancement film (DBEF).
18. The backlight unit according to claim 16 , further comprising a sealing member disposed between the light emitting diode and the optical member and comprising a light transmitting resin.
19. The backlight unit according to claim 18 , wherein the sealing member comprises a light diffusing agent dispersed in the light transmitting resin.
20. The backlight unit according to claim 16 , further comprising a dam disposed on the circuit board and surrounding the light emitting diode chip while being spaced apart from the light emitting diode chip,
wherein:
the light emitting diode and the dam are formed in plural; and
at least one of the dams has a portion having a curved shape.