Light-emitting diode (LED) module with light sensor configurations for optical feedback

• US 8,714,778 B2
• Filed: 06/26/2013
• Issued: 05/06/2014
• Est. Priority Date: 09/14/2010
• Status: Active Grant

• Current Assignee: Epistar Corporation (Ennostar, Inc.)
• Original Assignee: TSMC Solid State Lighting Ltd. (Ennostar, Inc.)
• Inventors: Tang, Yu-Sheng, Wu, Yi-Tsuo
• Primary Examiner(s): Williams, Joseph L
• Application Number:
  US13/927,421
• Publication Number:
  US 20130285102A1
• Time in Patent Office: 314 Days
• Field of Search: 362/230, 362/231, 362/800, 362/234, 362/253, 362/276, 362/802, 362/804, 362572-575, 315/312, 315/307, 315/149, 315/152, 315/360, 315/169.1, 315/169.3
• US Class Current: 362/276
• CPC Class Codes: H01L 2224/48091 Arched
• 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 2924/00014 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 2924/1305 Bipolar Junction Transistor [BJT]
• CPC Class Codes: H01L 2924/13091 Metal-Oxide-Semiconductor Field-Effect Transistor [MOSFET]
• CPC Class Codes: H01L 33/60 Reflective elements
• CPC Class Codes: H05B 45/22 using optical feedback

Abstract

An embodiment of the disclosure includes a LED module. A substrate is provided. A light sensor is positioned in the substrate. A LED chip is attached to the substrate. The LED chip has a first side and a second side. The second side is covered by an opaque layer with an opening. The opening is substantially aligned with the light sensor. The light sensor receives a light output emitting from the LED chip through the opening.

Claims

1. An apparatus, comprising:

a substrate;

a light-sensing element disposed in the substrate; and

a light-emitting diode (LED) chip disposed over, and electrically coupled to, the substrate, the LED chip containing a light-emitting layer and a light-reflective layer disposed between the light-emitting layer and the substrate, wherein the light-reflective layer includes an opening that is aligned with the light-sensing element.

2. The apparatus of claim 1, wherein the light-sensing element includes a photodiode.

3. The apparatus of claim 1, wherein the LED chip further comprises:

a first doped semiconductor layer and a second doped semiconductor layer disposed on opposite sides of the light-emitting layer, the first and second doped semiconductor layers having different types of conductivity; and

a growth substrate coupled to one of the first and second doped semiconductor layers.

4. The apparatus of claim 3, wherein the MQW layer is disposed between the growth substrate and the light-reflective layer.

5. The apparatus of claim 3, wherein the growth substrate is disposed between the MQW layer and the light-reflective layer.

6. The apparatus of claim 1, wherein the light-sensing element is wider than the opening.

7. The apparatus of claim 1, wherein:

the substrate includes a first side and a second side opposite the first side;

the LED chip is disposed over the first side of the substrate; and

the light-sensing element is disposed near the first side.

8. The apparatus of claim 7, further comprising:

a circuit board attached to the second side of the substrate; and

a lens disposed over the circuit board, wherein the substrate and the LED chip are housed within the lens.

9. The apparatus of claim 8, further comprising a further light sensor disposed over the circuit board and outside of the lens.

10. The apparatus of claim 8, further comprising:

a further LED chip disposed over the circuit board and housed within the lens, wherein the LED chip and the further LED chip are configured to emit different colors of light.

11. A method, comprising:

forming a light-sensing element in a substrate;

providing a light-emitting diode (LED) chip, the LED chip including;

a first doped semiconductor layer and a second doped semiconductor layer having different types of conductivity;

a light-emitting layer disposed between the first doped semiconductor layer and the second doped semiconductor layer; and

a light-reflective layer configured to reflect light emitted by the light-emitting layer, the light-reflective layer having an opening; and

bonding the LED chip to the substrate in a manner such that the opening of the light-reflective layer is aligned with the light-sensing element.

12. The method of claim 11, wherein the bonding the LED chip comprises bonding the LED chip through solder bumps.

13. The method of claim 11, wherein the bonding the LED chip comprises a wire bonding process.

14. The method of claim 11, further comprising:

attaching the substrate to a circuit board, wherein the circuit board and the LED chip are disposed on different sides of the substrate; and

forming a lens over the circuit board, the lens covering the LED chip and the substrate.

15. The method of claim 14, further comprising:

forming a further light sensor over an area of the circuit board outside of the lens.

16. The method of claim 14, further comprising:

providing a further LED chip;

bonding the further LED chip to a further substrate; and

attaching the further LED chip to the circuit board through the further substrate;

wherein;

the further LED chip is housed within the lens; and

the LED chip and the further LED chip are configured to emit different colors of light.

17. A method, comprising:

providing a light-emitting diode (LED) module that contains a circuit board and one or more LED components located over the circuit board, wherein each LED component includes an LED chip bonded to a substrate having an embedded light sensor;

sensing a first light and a second light emitted by the LED module, the first light having a first wavelength and the second light having a second wavelength;

comparing the first wavelength and the second wavelength to a predetermined target first wavelength and a predetermined target second wavelength; and

adjusting an electrical current driving the one or more LED components based on the comparing.

18. The method of claim 17, wherein:

the one or more LED components include a first LED component and a second LED component;

the first light is emitted by a first LED chip and sensed by a first light sensor of the first LED component; and

the second light is emitted by a second LED chip and sensed by a second light sensor of the second LED component.

19. The method of claim 17, wherein:

the LED module further includes a non-embedded light sensor disposed over the circuit board;

the first light is emitted by the LED chip and sensed by the embedded light sensor of one of the LED components; and

the second light is emitted by one of the LED components and sensed by the non-embedded light sensor.

20. The method of claim 17, wherein each LED chip includes a light-reflective layer with an opening that is aligned with the embedded light sensor.