Modulation system and modulation method

Patent metadata

Field	Value
Publication number	US-10193625-B2
Application number	US-201715697498-A
Country	US
Kind code	B2
Filing date	Sep 7, 2017
Priority date	Mar 8, 2016
Publication date	Jan 29, 2019
Grant date	Jan 29, 2019

Abstract

A system with which any abnormality can be easily found is provided. A system includes: a first modulator that generates a control signal and modulates an input signal in accordance with the generated control signal, to control luminance of a first light source that emits light according to the modulated input signal, the first modulator outputting the control signal; a second modulator that acquires the control signal output from the first modulator and modulates an input signal in accordance with the control signal, to control luminance of a second light source that emits light according to the modulated input signal, the second modulator outputting the control signal. The first modulator generates, as a light ID signal, a control signal for transmitting a visible light signal by luminance variations of the first light source, and acquires a light information signal being the control signal output from the second modulator.

First claim

What is claimed is:

1. A system comprising:
a first modulator configured to (i) generate a control signal, (ii) modulate a first voltage value of the first modulator to be more than or equal to a predetermined value or less than to the predetermined value according to the control signal, to control luminance of a first light source, and (iii) output the control signal; and
a second modulator configured to (i) acquire the control signal output from the first modulator and (ii) modulate a second voltage value of the second modulator to be more than or equal to the predetermined value or less than the predetermined value according to the control signal, to control luminance of a second light source, and (iii) output the control signal to the first modulator,
wherein the first modulator (i) generates, as a light information signal, the control signal for transmitting a visible light signal by change in luminance of the first light source, and (ii) acquires the light information signal being the control signal output from the second modulator.

2. The system according to claim 1 , further comprising a plurality of second modulators each structured as the second modulator and arranged in a predetermined order to form an array,
wherein the plurality of second modulators each acquire and output the control signal in accordance with the order in the array of the plurality of second modulators, such that the control signal is relayed from a top to an end of the array, and
the first modulator acquires, as an input light information signal, the light information signal being the control signal output from an endmost one of the second modulators in the array.

3. The system according to claim 2 , wherein the first modulator determines whether or not at least one of the plurality of second modulators has failed based on the input light information signal.

4. The system according to claim 3 , wherein the first modulator determines whether or not the input light information signal is correct, and when the first modulator determines that the input light information signal is not correct, the first modulator determines that at least one of the plurality of second modulators has failed.

5. The system according to claim 4 , wherein the first modulator determines that the input light information signal is not correct when the input light information signal is different from an original light information signal being the light information signal generated by the first modulator.

6. The system according to claim 5 , wherein the first modulator determines that the input light information signal is not correct when the original light information signal is at one of two different signal levels and the input light information signal is at other one of the two different signal levels.

7. The system according to claim 5 , wherein the first modulator determines that the input light information signal is not correct when a frequency of the input light information signal is different from a frequency of the original light information signal.

8. The system according to claim 7 , wherein the first modulator determines that the input light information signal is not correct when the frequency of the input light information signal is higher than the frequency of the original light information signal.

9. The system according to claim 5 , wherein the first modulator determines that the input light information signal is not correct when a duty ratio of the input light information signal is different from a duty ratio of the original light information signal.

10. The system according to claim 9 , wherein the first modulator determines that the input light information signal is not correct when a difference between the duty ratio of the input light information signal and the duty ratio of the original light information signal is equal to or greater than a predetermined value.

11. The system according to claim 4 , wherein, when the first modulator determines that at least one of the plurality of second modulators has failed, the first modulator further generates and outputs, as the control signal, a failure notifying signal that causes the first light source to blink in a pattern to be recognized by a human.

12. The system according to claim 4 , wherein, when the first modulator determines that at least one of the plurality of second modulators has failed, the first modulator further generates and outputs, as the control signal, a failure notifying signal that extinguishes the first light source.

13. An illumination device comprising the system according to claim 1 .

14. A display comprising the system according to claim 1 .

15. A projector comprising the system according to claim 1 .

16. A method for modulating an input signal, the method comprising:
generating, by a master modulator, a light information signal, which is a control signal for transmitting a visible light signal by a change in luminance of a first light source;
modulating, by the master modulator, the input signal according to the control signal, to control luminance of the first light source;
outputting, by the master modulator, the light information signal to a first slave modulator of a plurality of slave modulators arranged in a predetermined order;
acquiring and outputting, by each of the plurality of slave modulators, the light information signal in accordance with the predetermined order, such that the light information signal output from the master modulator is relayed from the first slave modulator to a last slave modulator of the plurality of slave modulators in the predetermined order;
modulating, by the plurality of slave modulators, the input signal according to the acquired light information signal, to control luminance of respective second light sources;
acquiring, by the master modulator, as an input light information signal, the light information signal output from the last slave modulator; and
determining, by the master modulator, whether or not at least one of the plurality of slave modulators has failed based on the input light information signal.

Assignees

• Panasonic Ip Corp America

Inventors

• Maeda Toshiyuki
• Oshimi Masanori
• Oku Hiroyuki

Classifications

• H05B47/21

  of two or more light sources connected in parallel · CPC title

• H04B10/116 Primary

  Visible light communication · CPC title

• H04B10/1125

  using a single common optical path · CPC title

• H04B3/54

  Systems for transmission via power distribution lines · CPC title

• H04B2203/5408

  using protocols · CPC title