Solid-state light source

• US 9,480,108 B2
• Filed: 04/18/2013
• Issued: 10/25/2016
• Est. Priority Date: 04/18/2012
• Status: Active Grant

• Current Assignee: Axlen Incorporated
• Original Assignee: Axlen Incorporated
• Inventors: Pi, Bo
• Primary Examiner(s): Wells, Kenneth B
• Application Number:
  US13/865,930
• Publication Number:
  US 20130278153A1
• Time in Patent Office: 1,286 Days
• Field of Search: 315/185.R, 315/291, 315/307
• US Class Current: 1/1
• CPC Class Codes: H05B 44/00 Circuit arrangements for operating electroluminescent light sources for operating light emitting diodes H05B45/00
• CPC Class Codes: H05B 45/20 Controlling the colour of the light
• CPC Class Codes: H05B 45/22 using optical feedback
• CPC Class Codes: H05B 45/48 having LEDs organised in strings and incorporating parallel shunting devices

Abstract

In one aspect, a light source module includes one or more light emitters of a first color forming a first color group, one or more light emitters of a second color forming a second color group, the one or more light emitters of the second color group connected in series to the one or more light emitters of the first color group, a second color group adjustment circuit connected in parallel to the one or more light emitters of the second color group, the second color group adjustment circuit configured to adjust one or both of color and intensity of output light of the second color group, and a current source connected in series to solid-state color emitters of the first and the second color groups.

Claims

1. A light source module, comprising:

one or more light emitters of a first color forming a first color group;

one or more light emitters of a second color forming a second color group, the one or more light emitters of the second color group connected in series with the one or more light emitters of the first color group;

a second color group adjustment circuit connected in parallel with the one or more light emitters of the second color group, the second color group adjustment circuit configured to adjust color, to adjust intensity of output light, or to adjust color and intensity of output light of the second color group; and

a current source connected in series with solid-state color emitters of the first and the second color groups, wherein the second color group adjustment circuit includes a feedback mechanism configured to simultaneously provide adjusted non-zero currents to flow through the one or more light emitters of the second color group and the second color group adjustment circuit, wherein a first sensing resistor is in series with the second color group and a second sensing resistor is in series with the second color group adjustment circuit and wherein the feedback mechanism senses currents at outputs of the first sensing resistor and the second sensing resistor.

2. The light source module of claim 1, wherein the one or more light emitters of the first color and the one or more light emitters of the second color are light emitting diodes (LEDs).

3. The light source module of claim 1, wherein the one or more light emitters of the first color and the one or more light emitters of the second color are laser diodes.

4. The light source module of claim 1, wherein the first color group is a yellow color group and the second color group is one of a red color group or a blue color group.

5. The light source module of claim 1, wherein the feedback mechanism is configured to control a ratio of the current that flows through the one or more light emitters of the second color group to the current that flows through the second color adjustment circuit.

6. The light source module of claim 1, wherein the second color adjustment circuit includes a programmable module to provide a current sink, the programmable module including:

an analog-to-digital converter (ADC) to convert an analog signal associated with the current to a digital signal,

a programmable microcontroller or CPU to process data corresponding to the digital signal to determine an adjusted current to flow through the one or more light emitters of the second color group,

a memory unit coupled to the programmable microcontroller or CPU to store at least one of processing algorithms or look-up table data, and

one or both of a digital-to-analog converter (DAC) and a pulse width modulation (PWM) output component to provide the adjusted current.

7. The light source module of claim 1, further comprising:

one or more light emitters of a third color forming a third color group, the one or more light emitters of the third color group connected in series with the one or more light emitters of the second color group; and

a third color group adjustment circuit connected in parallel with the one or more light emitters of the third color group, the third color group adjustment circuit configured to adjust color, to adjust intensity of output light, or to adjust color and intensity of output light of the third color group.

8. The light source module of claim 7, wherein the first color group is a yellow color group, the second color group is a red color group, and the third color group is a blue color group.

9. The light source module of claim 7, wherein the second color adjustment circuit is configured to adjust the current that flows through the one or more light emitters of the second color group.

10. The light source module of claim 7, wherein the second color adjustment circuit is configured to adjust the current that flows through the one or more light emitters of the second color group, and the third color adjustment circuit is configured to adjust the current that flows through the one or more light emitters of the third color group.

11. The light source module of claim 10, wherein the second color adjustment circuit includes a feedback mechanism to control a ratio of the current that flows through the one or more light emitters of the second color group to the current that flows through the second color adjustment circuit, and the third color adjustment circuit includes a feedback mechanism to control a ratio of the current that flows through the one or more light emitters of the third color group to the current that flows through the third color adjustment circuit.

12. The light source module of claim 10, wherein at least one of the second color adjustment circuit or the third color adjustment circuit includes a programmable module to provide a current sink, the programmable module including:

an ADC to convert an analog signal associated with the current to a digital signal,

a programmable microcontroller or CPU to process data corresponding to the digital signal to determine an adjusted current to flow through the one or more light emitters of the corresponding color group,

a memory unit coupled to the programmable microcontroller or CPU to store at least one of processing algorithms or look-up table data, and

one or both of a DAC and a PWM output component to provide the adjusted current.

13. The light source module of claim 12, wherein the programmable module further includes an interface port to provide connectivity to enable the capability to provide one or more of data, signaling information, or program code for storage in the memory unit.

14. The light source module of claim 12, wherein the programmable module operates using power supplied by the current source.

15. The light source module of claim 1, wherein the second color adjustment circuit includes one or more sensors configured to sense one or more of temperature, color value or intensity of light emitted by the second color group.

16. The light source module of claim 7, wherein the third color adjustment circuit includes one or more sensors configured to sense one or more of temperature, color value or intensity of light emitted by the third color group.

17. A method for producing a light of a particular color at an output of a light source module, comprising:

providing a current flow through a series of light emitters, wherein the series of light emitters comprises one or more light emitters of a first color and one or more light emitters of a second color; and

adjusting current flow through the light emitters of the second color, wherein adjusting the current flow is carried out by one or more iterations of;

measuring light output of the light source module, and

adjusting, based on the measured light output, a current flow through a second color adjustment circuit that is connected in parallel with the light emitters of the second color, wherein adjusted non-zero currents respectively flow through the light emitters of the second color and the color adjustment circuit to provide a combined light output of all light emitters of the first color and the second color with a particular color characteristic, wherein a first sensing resistor is in series with the second color group and a second sensing resistor is in series with the second color group adjustment circuit and wherein the feedback mechanism senses currents at outputs of the first sensing resistor and the second sensing resistor.

18. The method of claim 17, wherein the particular color characteristic includes one or more of a particular color index, a range of color values in a CIE color space, a color intensity value, or a color temperature value.

19. The method of claim 17, wherein the series of light emitters includes one or more additional light emitters corresponding to one or more additional colors.

20. The method of claim 19, wherein a particular color characteristic associated with all light emitters of the first color, the second color, and the additional colors is obtained by additionally adjusting current flow through the one or more additional light emitters.