Visible light communication apparatus

• US 9,553,667 B2
• Filed: 09/29/2014
• Issued: 01/24/2017
• Est. Priority Date: 10/07/2013
• Status: Active Grant

• Current Assignee: Panasonic Intellectual Property Management Co., Ltd. (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Intellectual Property Management Co., Ltd. (Panasonic Holdings Corporation)
• Inventors: Kido, Shojirou, Shiohama, Eiji, Matsukawa, Yoshihiko, Ikehara, Masaaki
• Primary Examiner(s): Vanderpuye, Ken N
• Assistant Examiner(s): Alagheband, Abbas H
• Application Number:
  US14/499,437
• Publication Number:
  US 20150098708A1
• Time in Patent Office: 848 Days
• Field of Search: 398/130, 398/118, 398/184, 398/65, 398/79, 315/397, 315/186
• US Class Current: 1/1
• CPC Class Codes: H04B 10/116 Visible light communication
• CPC Class Codes: H04B 10/25 Arrangements specific to fibre transmission
• CPC Class Codes: H04B 10/532 Polarisation modulation
• CPC Class Codes: H05B 45/37 Converter circuits
• CPC Class Codes: H05B 47/10 Controlling the light source
• CPC Class Codes: H05B 47/195 the transmission using visible or infrared light

Abstract

A visible light communication apparatus includes a constant current circuit and a load circuit including light emitting elements connected to output terminals of the constant current circuit. Further, the visible light communication apparatus includes a load variation circuit configured to change load characteristics of the load circuit by electrically connecting to the load circuit, the load variation circuit including a series circuit of a diode and a resistor connected in series to the load circuit and a switching element configured to electrically connect or disconnect the load variation circuit to the load circuit in response to a binary communication signal.

Claims

1. A visible light communication apparatus comprising:

a constant current circuit;

a load circuit including light emitting elements connected to output terminals of the constant current circuit;

a load variation circuit configured to change load characteristics of the load circuit by electrically connecting to the load circuit, the load variation circuit including a series circuit of a diode and a resistor connected in series to the load circuit; and

a switching element configured to electrically connect or disconnect the load variation circuit to the load circuit in response to a binary communication signal,

wherein the load variation circuit and the switching element are connected in parallel,

wherein the load variation circuit partially changes load characteristics of the load circuit,

wherein a resistance value of the resistor is greater than a resistance value of an equivalent resistance of the diode, and

wherein a modulation degree MH of illumination light of the light emitting elements as a result of turning the switching element on and off is represented by;

2. The visible light communication apparatus of claim 1, wherein the diode is a rectifier diode.

3. The visible light communication apparatus of claim 1, wherein the diode is a light emitting diode.

4. The visible light communication apparatus of claim 1,

wherein a magnitude of a load current flowing through the load circuit when the load variation circuit is electrically connected to the load circuit is smaller than a magnitude of a load current flowing through the load circuit when the load variation circuit is electrically disconnected from the load circuit.