ILLUMINATION DEVICE AND METHOD FOR EMBEDDING DATA SYMBOLS IN A LUMINANCE OUTPUT

• US 20120002974A1
• Filed: 03/08/2010
• Published: 01/05/2012
• Est. Priority Date: 03/13/2009
• Status: Active Grant

• Current Assignee: Signify Holding B.V. (Signify N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Schenk, Tim Corneel Wilhelmus, Wendt, Matthias, Radermacher, Harald Josef Günther, Kuppen, Johan Wilhelmus Hermanus
• Granted Patent: US 9,042,738 B2
• Time in Patent Office: Days
• US Class Current: 398/130
• CPC Class Codes: H04B 10/1149 Arrangements for indoor wireless networking of information
• CPC Class Codes: H04B 10/116 Visible light communication

Abstract

The invention relates to embedding data symbols of a data signal into a luminance output of an illumination device. The device includes a controller configured for receiving a first base pattern and a second base pattern within a frame period, and generating a shifted second pattern by phase shifting the second base pattern within the frame period with respect to the first base pattern in response to the data signal such that the data symbols are embedded in the luminance output of the device. The device also includes a first light source configured to generate a first luminance output in response to the first base pattern and a second light source configured to generate a second luminance output in response to the shifted second pattern. The first and second luminance outputs have different output spectra and the luminance output of the illumination device comprises both the first and second luminance outputs. With this approach, the short-time average light output of the illumination device remains constant, decreasing the visible flicker and allowing the use of lower switching frequencies relative to the prior art approaches.

Claims

1. An illumination device for embedding one or more data symbols of a data signal into a luminance output of the illumination device, the device comprising:

a controller configured for;

receiving a first base pattern within a frame period and a second base pattern within the frame period, and

generating a shifted second pattern by phase shifting the second base pattern within the frame period with respect to the first base pattern in response to the data signal such that the one or more of the data symbols are embedded in the luminance output of the illumination device;

a first light source configured to generate a first luminance output in response to the first base pattern; and

a second light source configured to generate a second luminance output in response to the shifted second pattern;

wherein;

the luminance output of the illumination device comprises the first luminance output and the second luminance output, and

the first luminance output and the second luminance output have different output spectra.

2. The illumination device of claim 1, wherein:

the controller is further configured for;

receiving a third base pattern within the frame period, and

generating a shifted third pattern by phase shifting the third base pattern within the frame period with respect to the first base pattern in response to the data signal such that the one or more of the data symbols are embedded in the luminance output of the illumination device; and

the device further comprises a third light source configured to generate a third luminance output in response to the shifted third pattern,

wherein;

the luminance output of the illumination device further comprises the third luminance output, and

the first luminance output, the second luminance output and the third luminance output have different output spectra.

3. The illumination device of claim 2, further comprising a demultiplexer configured to demultiplex the data signal into a first data stream and a second data stream, wherein the controller generates the shifted second pattern by phase shifting the second base pattern in response to the first data stream of the data signal and generates the shifted third pattern by phase shifting the third base pattern in response to the second data stream of the data signal.

4. The illumination device of claim 1, wherein the data signal is a binary signal and the one or more of the data symbols embedded in the luminance output are determined by a direction of phase shifting of the second base pattern with respect to the first base pattern.

5. The illumination device of claim 1, wherein the data signal is a multilevel signal and the one or more of the data symbols embedded in the luminance output are determined by a direction and an amount of phase shifting of the second base pattern with respect to the first base pattern.

6. The illumination device of claim 1, further comprising means for providing the first base pattern and the second base pattern, or derivatives thereof, to an optical receiver.

11. An illumination system comprising one or more illumination devices according to claim 1 and a remote control device for controlling the one or more illumination devices, the remote control comprising at least one optical receiver comprising:

an optical detector configured for separately detecting a first luminance output and a second luminance output of the illumination device, wherein the first luminance output and the second luminance output have different output spectra, and the luminance output of the illumination device comprises the first luminance output and the second luminance output; and

a processing unit configured for;

receiving a first base pattern within a frame period and a second base pattern within the frame period,

receiving a shifted second pattern based on the detected second luminance output of the illumination device,

determining a first phase difference between the second base pattern and the first base pattern for the frame period,

determining a second phase difference between the shifted second pattern and the first base pattern for the frame period, and

determining one or more data symbols of a data signal by comparing the second phase difference with the first phase difference for the frame period.

15. A computer program comprising software code portions configured for, when executed in the optical receiver according to claim 11, performing the steps comprising:

determining a first phase difference between a second base pattern and a first base pattern for a frame period;

determining a second phase difference between a shifted second pattern and the first base pattern for the frame period; and

determining one or more data symbols of a data signal by comparing the second phase difference with the first phase difference for the frame period.

16. The illumination system of claim 11, wherein the optical receiver further comprises a memory, wherein:

the first base pattern and the second base pattern are stored in the memory, and

the processing unit is configured to receive the first base pattern and the second base pattern from the memory.

17. The illumination system of claim 11, wherein the processing unit of the optical receiver is configured to receive the first base pattern and the second base pattern from an illumination device.

18. The illumination system of claim 11, wherein the data signal is a binary signal and the one or more of the data symbols are determined by a direction of phase shifting of the second base pattern with respect to the first base pattern.

7-10. -10. (canceled)

12. A method for embedding one or more data symbols of a data signal into a luminance output of an illumination device, the method comprising:

receiving a first base pattern and a second base pattern within a frame period;

generating a shifted second pattern by phase shifting the second base pattern within the frame period with respect to the first base pattern in response to the data signal comprising data symbols such that the one or more of the data symbols are embedded in the luminance output of the illumination device;

generating a first luminance output in response to the first base pattern; and

generating a second luminance output in response to the shifted second pattern;

wherein;

the luminance output of the illumination device comprises the first luminance output and the second luminance output, and

the first luminance output and the second luminance output have different output spectra.

13. The method of claim 12, further comprising the steps of:

receiving a third base pattern within the frame period; and

generating a third luminance output in response to a shifted third pattern,

wherein;

the shifted third pattern is generated by phase shifting the third base pattern within the frame period with respect to the first base pattern in response to the data signal comprising data symbols such that the one or more of the data symbols are embedded in the luminance output of the illumination device,

the luminance output of the illumination device further comprises the third luminance output, and

the first luminance output, the second luminance output and the third luminance output have different output spectra.

14. The method of claim 12, wherein the data signal is a binary signal and the one or more of the data symbols embedded in the luminance output are determined by a direction of phase shifting of the second base pattern with respect to the first base pattern.