METHOD OF VISIBLE LIGHT COMMUNICATION USING ILLUMINANCE SENSOR AND MOBILE COMMUNICATION TERMINAL FOR THE SAME

• US 20130016978A1
• Filed: 07/12/2012
• Published: 01/17/2013
• Est. Priority Date: 07/12/2011
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Son, Jae-Seung, Bae, Tae-Han, Won, Eun-Tae
• Granted Patent: US 8,965,218 B2
• Time in Patent Office: Days
• US Class Current: 398/118
• CPC Class Codes: H04B 10/116 Visible light communication
• CPC Class Codes: H04B 10/40 Transceivers
• CPC Class Codes: H04W 88/06 adapted for operation in multiple networks or having at least two operational modes, e.g. multi-mode terminals

Abstract

According to one embodiment, a photo detector-combined illuminance sensor includes a circuit for a Photo Detector (PD) function to detect the illuminance of the ambient environment. The illuminance sensor operates under the control of a controller in a visible light communication terminal. When an optical signal detected by the illuminance sensor is a visible light communication signal, the controller switches to cause the illuminance sensor to operate as the photo detector for the visible light communication in a visible light communication mode.

Claims

1. A mobile communication terminal configured to perform a visible light communication, the mobile communication terminal comprising:

an illuminance sensor configured to;

receive an optical signal, convert the optical signal to an electrical signal, and output the converted electrical signal; and

and

a controller configured to;

control the illuminance sensor to operate in one of a visible light communication mode and a illuminance measurement mode based on the signal output from the illuminance sensor.

2. The mobile communication terminal of claim 1, wherein the illuminance sensor comprises:

a light receiving element configured to receive the optical signal and convert the received optical signal to the electrical signal;

an optical data processor configured to measure an illuminance by using the electrical signal converted by the light receiving element;

an electric current amplifier configured to convert an illuminance value measured by the optical data processor to a current value;

a low noise amplifier configured to amplify the electrical signal converted by the light receiving element; and

a filter configured to remove DC noise from the signal amplified by the light receiving element.

3. The mobile communication terminal of claim 2, wherein the light receiving element comprises a photo diode.

4. The mobile communication terminal of claim 2, wherein the illuminance sensor further comprises:

a selector configured to interconnect the light receiving element and one of the low noise amplifier and the optical data processor.

5. The mobile communication terminal of claim 4, wherein, when an operation mode of the illuminance sensor is in the illuminance measurement mode, the controller is configured to control the selector to cause the selector configured to interconnect the light receiving element and the optical data processor to enable the electrical signal outputted from the light receiving element to be transferred to the optical data processor.

6. The mobile communication terminal of claim 4, wherein, when an operation mode of the illuminance sensor is in the visible light communication mode, the controller is configured to control the selector to cause the selector to interconnect the light receiving element and the low noise amplifier to enable the electrical signal outputted from the light receiving element to be transferred to the low noise amplifier.

7. The mobile communication terminal of claim 1, wherein the controller is configured to demodulate the signal outputted from the illuminance sensor to data based on a visible light communication scheme to determine whether the output signal is a visible light signal.

8. The mobile communication terminal of claim 2, further comprising a display unit having a backlight, a brightness of the backlight configured to be controlled according to the converted current value.

9. A method for visible light communication by a mobile communication terminal comprising an illuminance sensor, the method comprising:

demodulating a signal outputted from the illuminance sensor to data based on a visible light communication scheme in a visible light communication mode;

determining whether the output signal corresponds to a visible light communication signal by using the demodulated data; and

when the output signal does not correspond to a visible light communication signal, switching the visible light communication mode into an illuminance measurement mode for measuring an illuminance by the illuminance sensor.

10. The method of claim 9, wherein the signal outputted from the illuminance sensor in the visible light communication mode includes a signal obtained by converting an optical signal received through a light receiving element into an electrical signal, amplifying the converted electrical signal by a low noise amplifier, and then removing DC noise from the amplified signal by a filter.

11. The method of claim 9, further comprising:

when the mobile communication terminal is in the illuminance measurement mode, receiving an optical signal and converting the received optical signal to an electrical signal; and

measuring an illuminance by using the electrical signal.

12. The method of claim 10, further comprising:

interconnecting the light receiving element and the low noise amplifier to enable the electrical signal outputted from the light receiving element to be transferred to the low noise amplifier when the mobile communication terminal is in the visible light communication mode.

13. The method of claim 12, further comprising:

when the output signal corresponds to a visible light communication signal, controlling the illuminance sensor to operate the visible light communication mode.

14. The method of claim 9, further comprising:

controlling a brightness of a backlight of a display unit according to an illuminance measured by the illuminance sensor in the illuminance measurement mode.

15. A wireless device comprising:

an illuminance sensor configured to;

receive an optical signal and convert the optical signal to an electrical signal;

amplify, filter, and output the converted electrical signal when the mobile communication terminal is in a visible light communication mode; and

measure an illuminance by using the converted electrical signal and then output the measured illuminance when the mobile communication terminal is in an illuminance measurement mode; and

a controller configured to;

determine whether a signal output from the illuminance sensor includes a visible light communication signal; and

control the illuminance sensor to measure an illuminance when the signal output from the illuminance sensor is not a visible light communication signal.

16. The wireless device of claim 15, wherein the illuminance sensor comprises:

a light receiving element configured to receive the optical signal and convert the received optical signal to an electrical signal;

an optical data processor configured to measure an illuminance by using the electrical signal converted by the light receiving element;

an electric current amplifier configured to convert an illuminance value measured by the optical data processor to a current value;

a low noise amplifier configured to amplify the electrical signal converted by the light receiving element; and

a filter configured to remove DC noise from the signal amplified by the light receiving element.

17. The wireless device of claim 16, wherein the light receiving element comprises a photo diode.

18. The wireless device of claim 16, wherein the illuminance sensor further comprises:

a selector configured to interconnect the light receiving element and the low noise amplifier to enable the electrical signal outputted from the light receiving element to be transferred to the low noise amplifier under control of the controller when the mobile communication terminal is in the visible light communication mode.

19. The wireless device of claim 18, wherein, when the mobile communication terminal is in the illuminance measurement mode, the selector is configured to interconnect the light receiving element and the optical data processor to enable the electrical signal outputted from the light receiving element to be transferred to the optical data processor.

20. The wireless device of claim 19, wherein, when the output signal is not a visible light signal, the controller is configured to control the selector to cause the selector to interconnect the light receiving element and the optical data processor.