Light Emitting Device

• US 20170025395A1
• Filed: 07/22/2016
• Published: 01/26/2017
• Est. Priority Date: 07/22/2015
• Status: Abandoned Application

• Current Assignee: Everlight Electronics Company Limited
• Original Assignee: Everlight Electronics Company Limited
• Inventors: Tu, Ya Chin, Lin, Chun Min, Kang, Chieh-Yu, Chen, Chien-Chih
• Application Number:
  US15/216,839
• Publication Number:
  US 20170025395A1
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 33/483 Containers
• CPC Class Codes: H01L 33/505 characterised by the shape, e.g. plate or foil
• 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
• CPC Class Codes: H05B 45/30 Driver circuits

Abstract

A light emitting device including a first work circuit and a second work circuit is provided. The first work circuit includes a first LED chip and a first bonding adhesive. The first LED chip and the first bonding adhesive are electrically connected in series. The second work circuit includes a second LED chip. When an operation current of the first work circuit and an operation current of the second work circuit are the same, the first work circuit has a first voltage V_W1 and the second work circuit has a second voltage V_W2, wherein V_W1≈V_W2.

Claims

1. A light emitting device, comprising:

a first work circuit, comprising a first light emitting diode (LED) chip and a first bonding adhesive, wherein the first LED chip has a first forward voltage V1, and wherein the first LED chip and the first bonding adhesive are electrically connected in series; and

a second work circuit, comprising a second LED chip, wherein the second LED chip has a second forward voltage V2, and wherein a diversity ratio between the second forward voltage V2 and the first forward voltage V1 is greater than about 15%,

wherein the first work circuit has a first voltage drop V_W1, wherein the second work circuit has a second voltage drop V_W2, and wherein the first voltage drop V_W1 is approximately equal to the second voltage drop V_W2.

2. The light emitting device of claim 1, further comprising:

a third work circuit, comprising a third LED chip,

wherein the third work circuit has a third voltage drop V_W3, and wherein the first voltage drop V_W1 is approximately equal to the third voltage drop V_W3.

3. The light emitting device of claim 1, wherein the diversity ratio between the first forward voltage V1 and the second forward voltage V2 is greater than about 30%.

4. The light emitting device of claim 2, wherein the first LED chip is a red-light chip, and wherein each of the second LED chip and the third LED is a green-light chip or a blue-light chip.

5. The light emitting device of claim 1, wherein a ratio between V_W1 and V_W2 is about 0.785 to about 0.95.

6. The light emitting device of claim 1, wherein the first bonding adhesive comprises a resin composition that contains electrically conductive ceramic particles.

7. The light emitting device of claim 6, wherein the electrically conductive ceramic particles have a concentration of about 20% to about 80% based on weight percentage.

8. The light emitting device of claim 7, wherein the electrically conductive ceramic particles comprise indium-tin oxide particles, carbon particles, and a combination thereof.

9. The light emitting device of claim 8, wherein the resin composition comprises about 28% to about 30% of epoxy resin and about 70% to about 72% of indium-tin oxide particles based on weight percentage of the resin composition.

10. The light emitting device of claim 8, wherein the resin composition comprises about 48% to about 50% of epoxy resin and about 50% to about 52% of carbon particles based on weight percentage of the resin composition.

11. The light emitting device of claim 6, wherein the resin composition comprises metal particles.

12. The light emitting device of claim 2, wherein the first LED chip, the second LED chip and the third LED chip are electrically connected to an external power source in a common-anode or common-cathode manner.

13. The light emitting device of claim 1, wherein the first bonding adhesive has a thickness between 2 μ

m and 15 μ

m.

14. The light emitting device of claim 1, wherein the first bonding adhesive has an area between 0.015 mm² and 0.15 mm².

15. The light emitting device of claim 1, wherein the first bonding adhesive is applied through a screen printing process or a B-stage prepreg process.

16. The light emitting device of claim 1, further comprising a fluorescent powder covering the first LED chip, the second LED chip, or both the first LED chip and the second LED chip.

17. The light emitting device of claim 16, further comprising a retaining wall that is located between the first LED chip and the second LED chip.

18. The light emitting device of claim 16, wherein the retaining wall comprises a reflective material.

19. The light emitting device of claim 1, further comprising a second bonding adhesive configured to secure the second LED chip, wherein the second bonding adhesive and the second LED chip are electrically isolated.

20. The light emitting device of claim 2, further comprising a third bonding adhesive configured to secure the third LED chip, wherein the third bonding adhesive and the third LED chip are electrically isolated.