JP2005277809A - Illumination light communication system, illumination light modulating device and receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize data transmission by an illumination light in way of adding to an existing illumination device. <P>SOLUTION: An external optical modulator 12 for modulating intensity of an illumination light to be outputted from an illumination light source 10A of an illumination device 10. A storage device 14 stores ID information etc. for specifying the illumination device 10. A driving circuit 16 drives the device 12 in accordance with the ID information to be stored in the storing device 14 to repeatedly apply intensity modulation to the illumination light. Thus, the illumination light having been transmitted through the device 12 carries the ID information to be stored in the storage device 14. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an illumination light communication system that transmits information using illumination light, and an illumination light modulation device and a reception device used in the illumination light communication system.

  Patent Documents 1 to 3 describe information communication systems using lighting fixtures. Patent Documents 1 to 3 describe a so-called direct modulation method that modulates the intensity of the output light of the illumination light source by modulating the power source of the illumination light source. As light sources, fluorescent lamps and light emitting diodes (LEDs) have been studied.

  The information transmitted from the luminaire is, for example, ID information that identifies each luminaire, and this type of ID information can be used to identify the location and position where the luminaire is installed. Others are general information transferred from other equipment to the luminaire. Such general information is transferred from another device to a lighting fixture via a power transmission line and a data transmission medium such as a LAN (local area network).

Conventionally, GPS (Global Positioning System) is used as means for obtaining position information outdoors. However, the position cannot be measured unless it is a place where radio waves from GPS satellites can be received directly. Especially indoors, since radio waves from GPS satellites cannot be received, only low-accuracy position information can be obtained by other methods. By using the illumination light communication system, the position can be specified with high accuracy indoors.
Japanese Patent No. 3465017 JP-A-11-127170 JP 2002-290335 A

  However, power supply modulation in lighting equipment basically requires processing or replacement of the power supply circuit of the lighting fixture, which is inconvenient for recalling the illumination light communication system.

  An object of the present invention is to provide an illumination light communication system, an illumination light modulation device, and a reception device that can easily add an information communication function to an existing illumination light source.

  An illumination light communication system according to the present invention includes an external light modulator that can transmit illumination light from an illumination light source with different transmittances, a storage device that stores predetermined information, and the predetermined information stored in the storage device. A drive circuit that changes the transmittance of the external light modulator according to the predetermined information by driving the external light modulator, a light receiver that receives illumination light modulated by the external light modulator, and the light receiver And a restoration device that restores the predetermined information from the output signal.

  Illumination light modulation device according to the present invention. By driving the external light modulator according to the predetermined information stored in the storage device, the storage device storing the predetermined information, and the external light modulator capable of transmitting the illumination light from the illumination light source with different transmittances And a drive circuit that changes the transmittance of the external optical modulator according to the predetermined information.

  A receiving apparatus according to the present invention is an apparatus that receives information in an illumination light communication system that transmits information by modulating illumination light from an illumination light source, and a light receiver that receives the modulated illumination light; A first filter for extracting a component carrying the information from the output of the light receiver, a second filter for extracting a variable frequency component of the illumination light from the output of the light receiver, and A demodulation circuit that demodulates the information from the output and a demodulation control circuit that controls a demodulation timing of the demodulation circuit according to the output of the second filter are provided.

  ADVANTAGE OF THE INVENTION According to this invention, communication using illumination light is realizable, without carrying out repair replacement | exchange of the power supply part of lighting equipment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows a schematic block diagram of a first embodiment of the present invention.

  The existing lighting fixture 10 includes an illumination light source 10A such as a fluorescent lamp and a light-emitting diode, and a power supply circuit 10B that is connected to a commercial AC power source and supplies power for light emission to the illumination light source 10A. The illumination light source 10A is made of, for example, a fluorescent lamp, an incandescent bulb, or a light emitting diode. The lighting fixture 10 may be not only an indoor lighting fixture but also an outdoor lighting fixture and a guide light. The frequency of the commercial AC power supply is usually 50 Hz or 60 Hz. For example, in a fluorescent lamp, the power supply circuit 10B raises the driving frequency of the illumination light source 10A to a frequency higher than the commercial AC frequency, for example, about 1 kHz or more. Although an inverter may be built in, it is assumed here that the illumination light source 10A is driven at 50 Hz for easy understanding. Therefore, the luminance of the illumination light output from the illumination light source 10A varies at 100 Hz.

  In the present embodiment, an external light modulator 12 that modulates the intensity of illumination light, that is, an optical device that can externally control the transmittance of illumination light is disposed outside the illumination light source 10A. The external modulator 12 does not need to modulate all of the output illumination light of the illumination light source 10A, and may modulate only a part of the output illumination light of the illumination light source 10A. The storage device 14 stores ID information or the like that identifies the lighting fixture 10 in which the external light modulator 12 is installed. The drive circuit 16 operates with power from a commercial AC power source. The drive circuit 16 drives the external light modulator 12 so that the illumination light is repeatedly intensity-modulated according to the ID stored in the storage device 14. Thereby, the illumination light transmitted through the external light modulator 12 repeatedly conveys the ID stored in the storage device 14. Preferably, the drive circuit 16 drives the external modulator 12 in synchronism with the intensity variation of the illumination light so that data can be transmitted in a bright period of the illumination light.

  In the present embodiment, the external light modulator 12, the storage device 14, and the drive circuit 16 constitute an illumination light modulation device.

  The external light modulator 12 intensity-modulates the illumination light at a modulation frequency different from the luminance fluctuation frequency of the illumination light. A commonly available external light modulator uses, for example, a liquid crystal shutter. When the liquid crystal shutter is used as the external light modulator 12, the modulation frequency can be, for example, about several kHz.

  The mobile terminal 20 includes a mobile phone or a mobile information terminal, and includes the following components. The light receiver 22 receives the modulated illumination light and converts it into an electrical signal. The output electrical signal of the light receiver 22 is applied to a filter 24 that extracts a modulated signal component from the external modulator 12 and a filter 26 that extracts a change in luminance of illumination light output from the illumination light source 10A. The output of the filter 24 is applied to the demodulation circuit 28, and the output of the filter 26 is applied to the demodulation control circuit 30.

  The filter 26 extracts the luminance fluctuation frequency component of the illumination light from the output of the light receiver 22, and the demodulation control circuit 30 performs a demodulation operation in a period in which the illumination light has a sufficiently high luminance according to the output of the filter 26. The demodulation circuit 28 is controlled. The demodulating circuit 28 demodulates the output signal of the filter 24 in a period instructed by the demodulation control circuit 30, that is, a period in which the luminance of the illumination light is sufficiently high. By controlling the timing of the demodulation operation of the demodulation circuit 28 by the filter 26 and the demodulation control circuit 30, the ID can be received with a high signal-to-noise ratio regardless of the luminance fluctuation of the illumination light itself.

  The demodulation circuit 28 outputs the ID information obtained by the demodulation to the CPU 32. When the ID information indicates the position of the lighting fixture 10 as it is, the ID information may be displayed as it is. In such a case, the CPU 32 displays the ID information from the demodulation circuit 28 on the display device 34. When the ID information is merely a unique value that identifies the lighting fixture 10, it is necessary to convert the unique value into position information or the like. In that case, the CPU 32 inquires of the server 40 that manages the correspondence between the ID information and the position information via the communication control circuit 36. The server 40 converts the ID information from the mobile terminal 20 into corresponding position information and transmits it to the mobile terminal 20. The CPU 32 of the portable terminal 20 displays the position information obtained from the server 40 on the display device 34.

  The position information is not limited to latitude and longitude coordinates, and may be information indicating a small area in a wide area of a theme park, an amusement park, a large-scale exhibition hall, and a large-scale parking lot, for example. By displaying the position over the map, it is easy to grasp the position. If the correspondence between the ID and position of each illumination light source and the map data are downloaded to the portable terminal 20 in advance, it is not necessary to access the server 40 each time the ID is acquired. That is, the inquiry to the server 40 is not limited after the ID is acquired.

  This embodiment can also be used for attendance management in schools and the like. The acquired ID information is transmitted to the attendance management server together with the acquisition date information and the identification information of the portable terminal 20. Thereby, it can be easily confirmed that each student has attended a specific classroom at a specific date and time.

  FIG. 2 shows a schematic block diagram of the second embodiment of the present invention. In the embodiment shown in FIG. 1, the operating power of the drive circuit 16 is supplied from a commercial AC power supply. However, in the embodiment shown in FIG. 2, a solar cell 18 that generates power using illumination light output from the illumination light source 10A is provided. The solar cell 18 supplies the operating power of the drive circuit 16. Other configurations and operations are the same as those of the embodiment shown in FIG.

  In the first and second embodiments, fixed data is transmitted to the mobile terminal 20, but variable data can also be transmitted. FIG. 3 shows a schematic block diagram of a third embodiment capable of transmitting variable data. In the third embodiment, the power line can be used as a LAN (local area network) line. A data transmission system that can use a power line as a LAN (local area network) line is well known.

  The drive circuit 16A writes the data D from the power supply line to the storage device 14 or updates the storage information of the storage device 14 with the data D. The drive circuit 16A drives the external modulator 12 so as to repeatedly modulate the intensity of the illumination light output from the illumination light source 10A with the data D in accordance with the stored information in the storage device 14. In this configuration, variable data can be transmitted to the mobile terminal 20. The variable data is, for example, exhibition information in the vicinity of a location in a large-scale exhibition hall, special sale information on products in the vicinity of a location in a large-scale retail store, and attention information in a school. Of course, fixed information such as position information and general variable information can be transmitted alternately.

  In the present embodiment, the external light modulator 12, the storage device 14, and the drive circuit 16A constitute an illumination light modulation device.

  A normal wired or wireless LAN line may be connected to the drive circuit 16A, and data may be transmitted from an external server to the drive circuit 16A.

  FIG. 4 shows a schematic block diagram of a fourth embodiment of the present invention. In the present embodiment, information transmitted by illumination light can be changed. The same components as those in FIG. 1 are denoted by the same reference numerals. Changes to the embodiment shown in FIG. 1 will be described in detail.

  Similarly to the drive circuit 16, the drive circuit 16B drives the external light modulator 12 according to the information stored in the storage device 14, and repeatedly modulates the intensity of the illumination light. Thereby, the external light modulator 12 modulates the illumination light with the stored information of the storage device 14, and the modulated illumination light enters the portable terminal 20A. The part of the mobile terminal 20 </ b> A that receives the modulated illumination light is the same as the mobile terminal 20. In addition, the portable terminal 20A includes a modulation circuit 38 and an electric / optical converter 39 that converts an electric signal output from the modulator 38 into an optical signal, for example, a light emitting diode. Corresponding to these, the illumination light modulation device includes a light receiver 42 and a demodulation circuit 44.

  The modulation circuit 38 outputs a modulation signal that carries new information to be stored in the storage device 14. The electrical / optical converter 39 converts the modulation signal from the modulation circuit 38 into an optical signal and outputs the optical signal to the light receiver 42. The light receiver 42 converts the optical signal from the electrical / optical converter 39 into an electrical signal, and the demodulation circuit 44 demodulates the output electrical signal of the light receiver 42. The output of the demodulating circuit 44 is a signal indicating a new ID, and is applied to the driving circuit 16B. The drive circuit 16B writes the information from the demodulation circuit 44 into the storage device 14 or updates the information in the storage device 14 with the information from the demodulation device 44.

  In the present embodiment, the external light modulator 12, the storage device 14, the drive circuit 16B, the light receiver 42, and the demodulation circuit 44 constitute an illumination light modulation device.

  In this way, in the present embodiment, the data to be transmitted can be easily changed by modulating the illumination light. For example, variable data can be transmitted without providing a function of connecting to a network like the drive circuit 16A.

  Although the embodiment in which the modulation circuit 38 and the photoelectric converter 39 for changing the information are arranged in the portable terminal 20A that receives the information transmitted by the illumination light is illustrated, of course, the modulation circuit 38 and the photoelectric converter 39 are illustrated. May be installed in another portable terminal, for example, a dedicated portable terminal for changing data. It is easy to prevent transmission data from being changed by mischief.

  Although the invention has been described with reference to specific illustrative embodiments, various modifications and alterations may be made to the above-described embodiments without departing from the scope of the invention as defined in the claims. This is obvious to an engineer in the field to which the present invention belongs, and such changes and modifications are also included in the technical scope of the present invention.

It is a schematic block diagram of the first embodiment of the present invention. It is a schematic block diagram of the 2nd Example of this invention. It is a schematic block diagram of the 3rd Example of this invention. It is a schematic block diagram of the 4th Example of this invention.

Explanation of symbols

10: Lighting fixture 10A: Illumination light source 10B: Power supply circuit 12: External light modulator 14: Storage device 16, 16A, 16B: Drive circuit 18: Solar cell 20, 20A: Mobile terminal 22: Light receiver 24, 26: Filter 28 : Demodulation circuit 30: Demodulation control circuit 32: CPU
34: display device 36: communication control circuit 38: modulation circuit 39: photoelectric converter 40: server 42: light receiver 44: demodulation circuit

Claims (11)

An external light modulator (12) capable of transmitting illumination light from the illumination light source (10A) with different transmittances;
A storage device (14) for storing predetermined information;
A drive circuit (16, 16A, 16B) for changing the transmittance of the external light modulator according to the predetermined information by driving the external light modulator according to the predetermined information stored in the storage device (14);
A light receiver (22) for receiving illumination light modulated by the external light modulator (12);
Restoration device (24 to 28) for restoring the predetermined information from the output signal of the light receiver (22)
An illumination light communication system comprising:   The illumination light communication system according to claim 1, wherein the drive circuit (16B) stores the predetermined information transmitted from an external device in the storage device (14).   Furthermore, a receiving means (42) for receiving the predetermined information from an external device and an updating means (44, 16B) for updating the storage device (14) with the predetermined information received by the receiving means (42) are provided. The illumination light communication system according to claim 1. The restoration device is
A first filter (24) for extracting a component carrying the predetermined information from the output of the light receiver (22);
A second filter (26) for extracting the fluctuation frequency component of the illumination light from the output of the light receiver (22);
A demodulation circuit (28) for demodulating the predetermined information from the output of the first filter (24);
A demodulation control circuit (30) for controlling the demodulation timing of the demodulation circuit (28) according to the output of the second filter (26).
The illumination light communication system according to any one of claims 1 to 3, further comprising:   The illumination light communication system according to any one of claims 1 to 4, wherein the predetermined information includes information unique to the illumination light source. An external light modulator (12) capable of transmitting illumination light from the illumination light source (10A) with different transmittances;
A storage device (14) for storing predetermined information;
Drive circuits (16, 16A, 16B) for changing the transmittance of the external optical modulator according to the predetermined information by driving the external optical modulator according to the predetermined information stored in the storage device (14)
An illumination light modulation device comprising:   The illumination light modulation device according to claim 6, wherein the drive circuit (16B) stores the predetermined information transmitted from an external device in the storage device (14).   Furthermore, a receiving means (42) for receiving the predetermined information from an external device and an updating means (44, 16B) for updating the storage device (14) with the predetermined information received by the receiving means (42) are provided. The illumination light modulation device according to claim 6.   The illumination light modulation device according to claim 6, wherein the predetermined information includes information unique to the illumination light source. In an illumination light communication system for transmitting information by modulating illumination light from an illumination light source (10A), an apparatus for receiving the information,
A light receiver (22) for receiving the modulated illumination light;
A first filter (24) for extracting a component carrying the information from the output of the light receiver (22);
A second filter (26) for extracting the fluctuation frequency component of the illumination light from the output of the light receiver (22);
A demodulation circuit (28) for demodulating the information from the output of the first filter (24);
A demodulation control circuit (30) for controlling the demodulation timing of the demodulation circuit (28) according to the output of the second filter (26).
A receiving apparatus.   The receiving apparatus according to claim 10, wherein the information includes information unique to the illumination light source.

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