JP4676494B2 - Illumination light communication apparatus, illumination light communication method, and computer program - Google Patents

Description

The present invention relates to an illumination light communication apparatus , an illumination light communication method, and a computer program that communicate information using illumination light.

  Currently, the development of illumination optical communication technology is underway. The illumination light communication technology is generally a technology for performing information communication using illumination light emitted from illumination light irradiation means such as a lighting fixture installed indoors or an illumination lamp installed outdoors.

  In illumination light communication, a light-emitting diode (LED) is often used as a light source of illumination light irradiation means. With the recent progress of LED technology, bright white illumination light can be created by the LED. The LED can switch between light emission and non-light emission at high speed. If such a property of the LED is used, the illumination light can be modulated by digital information (pulse signal), and the digital information can be transmitted via the illumination light. Then, the illumination light modulated by the digital information is received by the light receiving element, and the digital information is extracted from the electrical signal corresponding to the illumination light, thereby realizing the reception of the digital information. Thus, information communication using illumination light is realized.

  For example, Japanese Laid-Open Patent Publication No. 2004-229273 discloses a method for performing information communication using illumination light.

JP 2004-229273 A

  By the way, in illumination light communication, the illumination light irradiated from light sources, such as a lighting fixture, is modulated with digital information (pulse signal). As a result, the brightness of the illumination light changes at high speed. In other words, the illumination light blinks at high speed.

  Although the illumination light is blinking, the blinking speed is high. Therefore, each change in the brightness of the illumination light corresponding to the change in the level of the pulse signal cannot be directly recognized through the human eye.

  However, when there is a bias in the arrangement of 0 and 1 in the digital information, the brightness of the illumination light seen over a relatively long period changes. Since this change in brightness is relatively slow, it may be recognized directly through the human eye.

  For example, if 0 continues in the digital information, the low level continues in the pulse signal, and the illumination light is dark or the illumination light is off for a long period. As a result, humans feel that the illumination light has become dark. On the other hand, if 1 continues in digital information, the human will feel that the illumination light has become brighter.

  For example, if illumination light emitted from a light source such as a lighting fixture is modulated by digital information due to such circumstances, flickering that can be directly recognized by humans may occur in the illumination light depending on the content of the digital information. . This is not preferable because it lowers the performance originally required for lighting fixtures, lighting lamps, etc., that is, the performance of illuminating an object to make it brighter and maintaining its brightness.

  The present invention has been made in view of the above-described problems, and a first object of the present invention is to flicker illumination light that can be directly recognized by humans even when the illumination light is modulated by information. An object of the present invention is to provide an illumination light communication device, an illumination light communication method, and a computer program that can be reduced.

  A second object of the present invention is to provide an illumination light communication device, an illumination light communication method, and a computer program capable of stabilizing the brightness (luminance) of illumination light modulated by information.

In order to solve the above problems, an illumination light communication apparatus according to the present invention is an illumination light communication apparatus that communicates information via illumination light, a light source that emits illumination light that is visible light, and an illumination that is emitted from the light source. A modulation unit that modulates light based on the information; and a light amount control unit that controls light emission by the light source so that a light amount per predetermined period of the illumination light modulated by the modulation unit is constant , The modulation means generates a first pulse signal corresponding to the information expressed by a binary code, and adds an adjustment pulse signal to the first pulse signal generated by the pulse signal generation means Adjusting pulse adding means for generating a second pulse signal, the light source emits illumination light whose brightness changes in accordance with the waveform of the second pulse signal, and the light quantity control means comprises: Adjustment pulse signal control means for changing the amplitude, duty ratio or length of the adjustment pulse signal is provided .

In order to solve the above problems, an illumination light communication method of the present invention is an illumination light communication method for communicating information via illumination light that is visible light emitted from a light source, and the illumination light is transmitted based on the information. A modulation step for modulating, and a light amount control step for controlling light emission in the light source so that the light amount per predetermined period of the illumination light modulated in the modulation step is constant . A pulse signal generating step for generating a first pulse signal corresponding to the information represented by a code, and a second pulse signal by adding an adjustment pulse signal to the first pulse signal generated by the pulse signal generating step. An adjustment pulse adding step for generating, the light source emits illumination light whose brightness changes in accordance with the waveform of the second pulse signal, and the light amount control step includes the adjustment pulse signal. An adjustment pulse signal control step for changing the amplitude, duty ratio, or length of the signal .

In order to solve the above problems, a computer program of the present invention causes a computer in the illumination light communication device (including various aspects thereof) of the present invention to function as a light amount control means .

In order to solve the above problems, a computer program product in a computer-readable medium clearly embodies a computer-executable program instruction, and includes the illumination light communication apparatus (including various aspects thereof ) of the present invention. The computer is caused to function as a light amount control means .

  According to the computer program product of the present invention, when the computer program product is read into a computer from a recording medium such as a ROM, CD-ROM, DVD-ROM, or hard disk storing the computer program product, or, for example, by a transmission wave. If the computer program product is downloaded to a computer via communication means, the above-described illumination light communication apparatus of the present invention can be implemented relatively easily. More specifically, the computer program product may be configured by computer-readable code (or computer-readable instructions) that functions as the illumination light communication device of the present invention described above.

  Such an operation and other advantages of the present invention will become apparent from the embodiments described below.

It is a block diagram which shows 1st Embodiment of the illumination light communication apparatus of this invention. It is explanatory drawing which shows the specific example at the time of applying the illumination light communication apparatus in FIG. 1 to an indoor illuminating device. It is explanatory drawing which shows the specific example at the time of applying the illumination light communication apparatus in FIG. 1 to an illumination lamp. It is a block diagram which shows the internal structure of the illumination light communication apparatus in FIG. 1 in detail. It is explanatory drawing which shows the communication information sent from the information source. It is a wave form diagram which shows the pulse signal corresponding to the communication information before a biphase encoding process, the pulse signal corresponding to the communication information after a biphase encoding process, and the pulse signal after a waveform inversion process. It is a block diagram which shows 2nd Embodiment of the illumination light communication apparatus of this invention. It is a circuit diagram which shows the more specific one aspect | mode of 2nd Embodiment of the illumination optical communication apparatus of this invention. It is a block diagram which shows 3rd Embodiment of the illumination light communication apparatus of this invention. It is a circuit diagram which shows the more specific one aspect | mode of 3rd Embodiment of the illumination optical communication apparatus of this invention. It is a block diagram which shows 4th Embodiment of the illumination light communication apparatus of this invention. It is a circuit diagram which shows the more specific one aspect | mode of 4th Embodiment of the illumination optical communication apparatus of this invention. It is a wave form diagram which shows the pulse signal produced | generated by adding an adjustment pulse signal to the pulse signal produced | generated by the pulse signal generation circuit. It is a block diagram which shows 5th Embodiment of the illumination light communication apparatus of this invention. It is a wave form diagram which shows the pulse signal by which the pulse signal produced | generated by the pulse signal production | generation part, the pulse signal divided | segmented by the pulse division | segmentation part, and the number of division | segmentation pulses was changed by the pulse number control part.

Explanation of symbols

1, 60, 70, 80, 90, 100, 110, 120 Illumination light communication device 11, 66, 86, 106, 126 Light source 12, 61, 81, 101, 121 Modulator 13, 63, 83, 104, 124 Control unit 41 Bi-phase encoding processing unit 42, 62, 82, 102, 122 Pulse signal generation unit 43 Waveform inversion unit 51 Communication information 64 Light amount detection unit 65, 85 Amplitude control unit 84 Integral value acquisition unit 105 Adjustment pulse signal control unit 123 Pulse division unit 125 Pulse number control unit

  Hereinafter, the best mode for carrying out the present invention will be described in order for each embodiment based on the drawings.

(First embodiment)
FIG. 1 shows a first embodiment of the illumination light communication apparatus of the present invention. An illumination light communication device 1 in FIG. 1 is a device that communicates information via illumination light. The illumination light communication device 1 can communicate information of various forms, types, and contents. However, it is desirable that the form of information communicated by the illumination light communication device 1 is digital information expressed by a binary code. However, in the case of analog information, for example, the analog information may be converted into binary digital information by an analog-to-digital converter, and then communication may be performed. Is converted into binary digital information and then communication is performed. Hereinafter, for convenience of explanation, information communicated through illumination light is referred to as “communication information”.

  As shown in FIG. 1, the illumination light communication device 1 includes a light source 11, a modulation unit 12, and a light amount control unit 13.

  The light source 11 spontaneously emits illumination light. The illumination light is visible light. The illumination light is preferably white light. The light source 11 is preferably a light emitting diode (LED). Further, the light source 11 is preferably a light emitting diode that emits white light, that is, a white light emitting diode. However, instead of the white light emitting diode, the light source 11 may be configured by a combination of a blue light emitting diode, a green light emitting diode, and a red light emitting diode. Further, instead of the light emitting diodes, other light emitting elements that spontaneously emit visible light and can switch between light emission and non-light emission at high speed (for example, organic electroluminescence elements, inorganic electroluminescence elements, or silicon light emitting elements) Etc.) may constitute the light source 11.

  The modulation unit 12 modulates the illumination light emitted from the light source 11 based on the communication information. The light amount control unit 13 controls light emission by the light source 11 so that the light amount per predetermined period of the illumination light modulated by the modulation unit 12 is constant. Specifically, the light amount control unit 13 controls generation of illumination light by the light source 11 or modulation of illumination light by the modulation unit 12. Further specific description of the modulation unit 12 and the light amount control unit 13 will be described later.

  FIG. 2 shows a specific example when the illumination light communication device 1 is applied to an indoor lighting device. The indoor lighting device 20 in FIG. 2 has both a function as indoor lighting and a function of communicating communication information via illumination light.

  As shown in FIG. 2, in the indoor lighting device 20, a plurality of white light emitting diodes 11 </ b> A, 11 </ b> A,... These white light emitting diodes 11 </ b> A are covered with a transparent cover 22. The light emitting diode array plate 21 is attached to the attachment unit 23, and is further attached to the ceiling 24 via the attachment unit 23. A modulation unit 12 and a light amount control unit 13 are provided inside the mounting unit 23.

  The white light emitting diode 11A emits white illumination light. The modulation unit 12 modulates the illumination light based on communication information sent from the information source. That is, the white light emitting diode 11A emits illumination light modulated based on communication information. Thereby, the indoor lighting device 20 communicates communication information with various devices such as information home appliances, personal computers, and AV (Audio Vidual) devices in the place where the illumination light hits indoors via the illumination light. It can be carried out. For example, the indoor lighting device 20 communicates communication information with a refrigerator 31 having a communication function, a PDA (Personal Digital Assistance) 32, a notebook personal computer 33, a DVD recorder 34 having a communication function, and the like. Can do.

  The light amount control unit 13 controls the light amount of the illumination light emitted from the white light emitting diode 11A so that the light amount per predetermined period of the illumination light modulated by the modulation unit 12 is constant. Thereby, the brightness of the illumination light emitted from the white light emitting diode 11A is stabilized, and flickering of the illumination light is reduced.

  FIG. 3 shows a specific example when the illumination light communication apparatus 1 is applied to an illumination lamp. The illuminating lamp 30 in FIG. 3 has both a function as outdoor illumination and a function of communicating communication information through illumination light.

  As shown in FIG. 3, in the illuminating lamp 30, a plurality of white light emitting diodes 11 </ b> B, 11 </ b> B,. In addition, a modulation unit 12 and a light amount control unit 13 are provided in a storage box 42 provided at the lower end of the column 41.

  The white light emitting diode 11B emits white illumination light. The modulation unit 12 modulates the illumination light based on communication information sent from the information source. Thereby, the illuminating lamp 30 communicates communication information with the apparatus in the place where the illuminating light hits, for example, the communication apparatus provided in the automobile passing under the illuminating lamp 30 via the illuminating light. be able to.

  The light amount control unit 13 controls the light amount of the illumination light emitted from the white light emitting diode 11B so that the light amount per predetermined period of the illumination light modulated by the modulation unit 12 is constant. Thereby, the brightness of the illumination light emitted from the white light emitting diode 11B is stabilized, and flickering of the illumination light is reduced.

  FIG. 4 shows the internal structure of the illumination light communication device 1 in FIG. 1 in detail. As shown in FIG. 4, the light quantity control unit 13 includes a biphase encoding processing unit 41. The modulation unit 12 includes a pulse signal generation unit 42 and a waveform inversion unit 43. The bi-phase encoding processing unit 41, the pulse signal generation unit 42, and the waveform inversion unit 43 can be configured by a microcomputer, a multiprocessor, or the like in which an arithmetic device, a control device, a logic circuit, a storage element, and the like are incorporated.

  The operation of the illumination light communication apparatus 1 will be described with reference to FIGS. 5 and 6. FIG. 5 shows communication information and the like sent from the information source. FIG. 6 shows a pulse signal P11 corresponding to communication information before the bi-phase encoding process, a pulse signal P12 corresponding to communication information after the bi-phase encoding process, and a pulse signal P13 after the waveform inversion process.

  First, communication information 51 is sent from the information source to the illumination light communication apparatus 1. When the illumination light communication device 1 is applied to an indoor lighting device 20 as shown in FIG. 2, the information source is, for example, a main provided in any place of a building including a room where the indoor lighting device 20 is provided. A computer (for example, a personal computer). When the illumination light communication device 1 is applied to an illuminating lamp 30 as shown in FIG. 3, the information source is, for example, a computer base provided in a communication base, an information center of an intelligent road traffic system (ITS), or the like. It is.

  As shown in FIG. 5, the synchronization information 52 and the reception blank 53 are added to the communication information 51 sent from the information source. The synchronization information 52 is information for synchronizing the information source and the illumination light communication device 1. The reception blank 53 is provided for two-way communication between the illumination light communication device 1 and a communication device (for example, the refrigerator 31, the PDA 32, the notebook personal computer 33, the DVD recorder 34, etc. in FIG. 2). It is blank. That is, the illumination light communication apparatus 1 transmits the communication information 51 to the communication device via the illumination light. In response to this, the communication device transmits response information to the illumination light communication device 1 through a wireless communication medium such as white visible light or infrared light. The illumination light communication device 1 receives this response information. The reception blank 53 is provided to secure time for receiving this response information.

  A header 54 is provided at the head of the communication information 51. The header 54 includes identification information for identifying individual communication devices that communicate with the illumination light communication device 1. For example, when the illuminating light communication apparatus 1 communicates with four communication devices such as the refrigerator 31, the PDA 32, the notebook personal computer 33, and the DVD recorder 34 in FIG. Such identification information is included. That is, when identification numbers such as “01” are assigned to the refrigerator 31, “02” to the PDA 32, “03” to the notebook personal computer, and “04” to the DVD recorder 34, “01”, “02”, Identification information indicating “03” or “04” is included in the header 54. Each communication device can determine whether or not the communication information 51 transmitted from the illumination light communication device 1 is the communication information 51 addressed to itself, based on the identification information. Thereby, the illumination light communication apparatus 1 can communicate with one of a plurality of communication devices.

  When the communication information 51 is sent from the information source to the illumination light communication device 1, the communication information 51 is first supplied to the bi-phase encoding processing unit 41. The bi-phase encoding processing unit 41 performs bi-phase encoding processing on the communication information 51. Subsequently, the pulse signal generation unit 42 generates a pulse signal P12 corresponding to the communication information 51 that has been subjected to the biphase encoding processing by the biphase encoding processing unit 41.

  The biphase encoding process is, for example, the following process. That is, if the pulse signal corresponding to the communication information 51 before the bi-phase encoding process is, for example, the pulse signal P11 in FIG. 6, in the bi-phase encoding process, the high level part of the pulse signal P11 is the duty ratio. Is converted into a first pulse a of 50%. Further, the low level portion of the pulse signal P11 is converted into a second pulse b having a duty ratio of 50% and a phase different from the first pulse a by 180 degrees. In this way, the pulse signal P11 is converted into a pulse signal P12 having a duty ratio of 50% as a whole.

  Subsequently, the waveform inverting unit 43 determines that the pulse signal P11 corresponding to the communication information 51 before the biphase encoding process is low level (or high level) in the pulse signal P12 corresponding to the communication information 51 after the biphase encoding process. The waveform of the section corresponding to the section of (may be) may be inverted. That is, as shown in FIG. 6, the waveform inversion unit 43 inverts a portion corresponding to the second pulse b of the pulse signal P12. Thereby, the pulse signal P12 is converted into a pulse signal P13. According to this waveform inversion process, in the pulse signal P13, a pulse always rises at a position corresponding to a position where the level of the pulse signal P11 is inverted. Thus, by performing signal processing based on the rising position of the pulse in the pulse signal P13, the original information, that is, the communication information 51 before the bi-phase encoding process can be restored easily and with high accuracy.

  Subsequently, the pulse signal P <b> 13 is supplied from the waveform inversion unit 43 to the light source 11. The light source 11 emits illumination light modulated by the pulse signal P13, that is, illumination light whose brightness changes in accordance with the waveform of the pulse signal P13.

  Since the average frequency of the pulse signal P13 is, for example, about 100 kHz or more, a change in the brightness of the illumination light corresponding to the waveform of the pulse signal P13 cannot be directly recognized by human eyes. Further, since the pulse signal P13 is a pulse signal having a duty ratio of 50% as a whole, the amount of illumination light modulated by the pulse signal P13 per predetermined period (for example, about 0.5 to 1 second) is substantially constant. Become. Thereby, the brightness of the illumination light emitted from the light source 11 is maintained over a long period of time regardless of the contents of the communication information 51, that is, the arrangement state of “1” and “0” in the communication information 51 (the light source 11 emits the illumination light). It is almost constant)

  As described above, the illumination light communication apparatus 1 performs bi-phase encoding processing on communication information, sets the duty ratio of the pulse signal corresponding to the communication information to 50%, and modulates the illumination light by this pulse signal. Therefore, the amount of illumination light per predetermined period can be made substantially constant. Therefore, the brightness (luminance) of illumination light can be stabilized, and flickering of illumination light that can be directly recognized by humans can be reduced. As a result, when the illumination light communication device 1 is applied to an indoor lighting device (see FIG. 2), an illuminating lamp (see FIG. 3), etc., the original performance as these illuminations, that is, light is applied to the object to make it brighter, The performance of maintaining the brightness can be maintained or improved.

  Moreover, in the illumination light communication apparatus 1, the structure which makes constant the light quantity of illumination light by performing the biphase encoding process was employ | adopted. As a result, the configuration is simplified compared to a case where a configuration in which the amount of illumination light is detected and the detection result is fed back to adjust the amount of illumination light (for example, the illumination light communication device 60 described later) is adopted. Reduction of the number of parts can be realized.

  1 to 4 is a specific example of the modulation unit, and the light amount control unit 13 is a specific example of the light amount control unit. The biphase encoding processing unit 41 in FIG. 4 is a specific example of the biphase encoding processing means, the pulse signal generation unit 42 is a specific example of the pulse signal generation means, and the waveform inversion unit 43 is a specific example of the waveform inversion means. It is an example.

(Second Embodiment)
FIG. 7 shows a second embodiment of the illumination light communication apparatus of the present invention. The illumination light communication device 60 in FIG. 7 detects the light amount per predetermined period of the illumination light, and changes the amplitude of the pulse signal for modulating the illumination light so that the detected light amount is constant. Is adopted.

  That is, in the illumination light communication device 60, the modulation unit 61 includes a pulse signal generation unit 62. The light quantity control unit 63 includes a light quantity detection unit 64 and an amplitude control unit 65.

  The operation of the illumination light communication device 60 is as follows. When communication information is sent from the information source, the pulse signal generation unit 62 generates a pulse signal corresponding to the communication information. The light source 66 emits illumination light whose brightness changes in accordance with the waveform of the pulse signal generated by the pulse signal generation unit 62. The light amount detection unit 64 detects the light amount per predetermined period of the illumination light emitted from the light source 66. The amplitude control unit 65 changes the amplitude of the pulse signal generated by the pulse signal generation unit 62 so that the light amount detected by the light amount detection unit 64 becomes a predetermined light amount.

  FIG. 8 shows a more specific example of the illumination light communication device 60 according to the second embodiment of the present invention. 8 includes a pulse signal generation circuit 71, an amplifier 72, a white light emitting diode (white LED) 73, a light receiving element 74, an integration circuit 75, a reference value output circuit 76, and a comparator 77. . The light receiving element 74 is provided at a place where the illumination light emitted from the white light emitting diode 73 hits. Taking the indoor lighting device 20 in FIG. 2 as an example, the light receiving element 74 is attached to, for example, the central portion of the inner surface of the transparent cover.

  The operation of the illumination light communication device 70 is as follows. When communication information is sent from the information source, the pulse signal generation circuit 71 generates a pulse signal P21 corresponding to the communication information. For example, a pulse signal P21 having amplitudes of high level and low level corresponding to the codes “1” and “0” in the communication information is generated. The amplifier 72 amplifies the pulse signal P21 and supplies it to the white light emitting diode 73 as the pulse signal P22. The white light emitting diode 73 emits illumination light modulated by the pulse signal P22, that is, illumination light whose brightness changes in accordance with the waveform of the pulse signal P22.

  Subsequently, the light receiving element 74 receives the illumination light emitted from the white light emitting diode 73, generates an electrical signal whose amplitude changes according to the intensity of the illumination light, and supplies the electrical signal to the integration circuit 75. The integrating circuit 75 generates an integrated value per predetermined period (for example, about 0.5 to 1 second) of the electric signal, and supplies the integrated value to one input terminal of the comparator 77. A predetermined reference value is input from the reference value output circuit 76 to the other input terminal of the comparator 77. The comparator 77 compares the integrated value supplied from the integrating circuit 75 with a predetermined reference value, and supplies a DC control signal having a voltage corresponding to the difference between the two to the amplifier 72.

  The amplifier 72 changes the amplification factor according to the voltage of this control signal. As a result, the amplitude of the pulse signal P22 changes according to the voltage of the control signal, that is, the difference between the integrated value supplied from the integrating circuit 75 and the predetermined reference value. More specifically, when the integrated value supplied from the integrating circuit 75 is larger than a predetermined reference value, the voltage of the control signal supplied from the comparator 77 to the amplifier 72 becomes negative, which causes the amplifier 72 to Gain is reduced. Therefore, the amplitude of the pulse signal P22 is reduced, and as a result, the amount of illumination light per predetermined period is reduced. On the other hand, when the integrated value supplied from the integrating circuit 75 is smaller than a predetermined reference value, the voltage of the control signal supplied from the comparator 77 to the amplifier 72 becomes positive, and thereby the amplification factor of the amplifier 72 increases. Therefore, the amplitude of the pulse signal P22 increases, and as a result, the amount of illumination light per predetermined period increases. By repeating such an operation, the light quantity per predetermined period of the illumination light converges to a constant light quantity.

  As described above, the illumination light communication devices 60 and 70 detect the light amount per predetermined period of the illumination light, and the amplitude of the pulse signal for modulating the illumination light so that the detected light amount is constant. Change. Thereby, the light quantity per predetermined period of illumination light can be made substantially constant. Therefore, the brightness (luminance) of illumination light can be stabilized, and flickering of illumination light that can be directly recognized by humans can be reduced.

  Further, the illumination light communication devices 60 and 70 employ a configuration in which the light amount per predetermined period of the illumination light actually emitted is detected, and the light amount per predetermined period of the illumination light is feedback-controlled using the detection result. Yes. For this reason, the amount of illumination light can be made constant with high accuracy.

  In the illumination light communication device 70, an integration value per predetermined period is generated by the integration circuit 75 and used for comparison by the comparator 77. However, an average value may be used instead of the integral value. For example, the integrated value per predetermined period generated by the integrating circuit 75 may be divided by the length of the predetermined period to generate an average value, which may be used for comparison by the comparator 77.

  In FIG. 7, the modulation unit 61 is a specific example of the modulation unit, and the light amount control unit 63 is a specific example of the light amount control unit. The pulse signal generation unit 62 is a specific example of the pulse signal generation unit, the light amount detection unit 64 is a specific example of the light amount detection unit, and the amplitude control unit 65 is a specific example of the amplitude control unit. In FIG. 8, a pulse signal generation circuit 71 is a specific example of the pulse signal generation means. The white light emitting diode 73 is a specific example of the light source. The light receiving element 74 and the integrating circuit 75 are specific examples of the light amount detecting means. The reference value output circuit 76, the comparator 77, and the amplifier 72 are specific examples of the amplitude control means.

(Third embodiment)
FIG. 9 shows a third embodiment of the illumination light communication apparatus of the present invention. The illumination light communication device 80 in FIG. 9 acquires the integral value per predetermined period of the pulse signal for modulating the illumination light, and adjusts the amplitude of the pulse signal so that the acquired integral value is constant. A configuration that changes is adopted.

  That is, in the illumination light communication device 80, the modulation unit 81 includes a pulse signal generation unit 82. The light quantity control unit 83 includes a light quantity detection unit 84 and an amplitude control unit 85.

  The operation of the illumination light communication device 80 is as follows. When communication information is sent from the information source, the pulse signal generation unit 82 generates a pulse signal corresponding to the communication information. The light source 86 emits illumination light whose brightness changes in accordance with the waveform of the pulse signal generated by the pulse signal generation unit 82. The integral value acquisition unit 84 acquires an integral value per predetermined period of the pulse signal supplied from the pulse signal generator 82 to the light source 86. The amplitude controller 85 changes the amplitude of the pulse signal generated by the pulse signal generator 82 so that the integrated value acquired by the integrated value acquisition unit 84 becomes a predetermined reference value.

  FIG. 10 shows a more specific example of the illumination light communication device 80 according to the third embodiment of the present invention. The illumination light communication device 90 in FIG. 10 includes a pulse signal generation circuit 91, an amplifier 92, a white light emitting diode (white LED) 93, an integration circuit 94, a reference value output circuit 95, and a comparator 96.

  The operation of the illumination light communication device 90 is as follows. When communication information is sent from the information source, the pulse signal generation circuit 91 generates a pulse signal P31 corresponding to the communication information. For example, a pulse signal P31 having amplitudes of high level and low level corresponding to the codes “1” and “0” in the communication information is generated. The amplifier 92 amplifies the pulse signal P31 and supplies it to the white light emitting diode 93 as the pulse signal P32. The white light emitting diode 93 emits illumination light modulated by the pulse signal P32, that is, illumination light whose brightness changes in accordance with the waveform of the pulse signal P32.

  The pulse signal P32 output from the amplifier 92 is also supplied to the integrating circuit 94. The integration circuit 94 generates an integration value per predetermined period (for example, about 0.5 to 1 second) of the pulse signal P32 and supplies this integration value to one input terminal of the comparator 96. A predetermined reference value is input from the reference value output circuit 95 to the other input terminal of the comparator 96. The comparator 96 compares the integrated value supplied from the integrating circuit 94 with a reference value, and supplies a DC control signal having a voltage corresponding to the difference between the two to the amplifier 92.

  The amplifier 92 changes the amplification factor according to the voltage of this control signal. As a result, the amplitude of the pulse signal P32 changes according to the voltage of the control signal, that is, the difference between the integrated value supplied from the integrating circuit 94 and the reference value. More specifically, when the integration value supplied from the integration circuit 94 is larger than the reference value, the voltage of the control signal supplied from the comparator 96 to the amplifier 92 becomes negative, thereby the amplification factor of the amplifier 92 is increased. Go down. Therefore, the amplitude of the pulse signal P32 is reduced, and as a result, the amount of illumination light per predetermined period is reduced. On the other hand, when the integral value supplied from the integration circuit 94 is smaller than the reference value, the voltage of the control signal supplied from the comparator 96 to the amplifier 92 becomes positive, thereby increasing the amplification factor of the amplifier 92. Therefore, the amplitude of the pulse signal P32 increases, and as a result, the amount of illumination light per predetermined period increases. By repeating such an operation, the light quantity per predetermined period of the illumination light converges to a constant light quantity.

  As described above, in the illumination light communication devices 80 and 90, the pulse signal for modulating the illumination light is obtained with an integral value per predetermined period, and the pulse signal is set so that the obtained integral value becomes constant. Change the amplitude of. Thereby, the light quantity per predetermined period of illumination light can be made substantially constant. Therefore, the brightness (luminance) of illumination light can be stabilized, and flickering of illumination light that can be directly recognized by humans can be reduced.

  In addition, the illumination light communication devices 80 and 90 obtain an integral value per predetermined period of the pulse signal actually supplied to the light source 93, and feedback control the light amount per predetermined period of the illumination light using this integral value. The configuration is adopted. For this reason, the amount of illumination light can be made constant with high accuracy.

  In FIG. 9, the modulation unit 81 is a specific example of the modulation unit, and the light amount control unit 83 is a specific example of the light amount control unit. The pulse signal generation unit 82 is a specific example of the pulse signal generation unit, the integral value acquisition unit 84 is a specific example of the integration value acquisition unit, and the amplitude control unit 85 is a specific example of the amplitude control unit. In FIG. 10, a pulse signal generation circuit 91 is a specific example of the pulse signal generation means. The white light emitting diode 93 is a specific example of the light source. The integration circuit 94 is a specific example of the integrated value acquisition means. The reference value output circuit 95, the comparator 96, and the amplifier 92 are specific examples of the amplitude control means.

(Fourth embodiment)
FIG. 11 shows a fourth embodiment of the illumination light communication apparatus of the present invention. In the illumination light communication apparatus 100 in FIG. 11, the adjustment pulse signal is added to the pulse signal corresponding to the communication information, and the illumination light is modulated by the pulse signal to which the adjustment pulse signal is added. Then, the amplitude of the adjustment pulse signal is changed so that the amount of illumination light per predetermined period is constant.

  That is, in the illumination light communication apparatus 100, the modulation unit 101 includes a pulse signal generation unit 102 and an adjustment pulse addition unit 103. The light amount control unit 104 includes an adjustment pulse signal control unit 105.

  The operation of the illumination light communication apparatus 100 is as follows. When communication information is sent from the information source, the pulse signal generation unit 102 generates a first pulse signal corresponding to the communication information. Subsequently, the adjustment pulse adding unit 103 generates the second pulse signal by adding the adjustment pulse signal to the first pulse signal generated by the pulse signal generation unit 102. The light source 106 emits illumination light whose brightness changes according to the waveform of the second pulse signal generated by the adjustment pulse adding unit 103. The adjustment pulse signal control unit 105 changes the amplitude of the adjustment pulse signal so that the amount of illumination light emitted from the light source 106 per unit time is constant. As a method of changing the amplitude of the adjustment pulse signal in order to make the amount of light constant, the amount of illumination light emitted from the light source 106 is detected in substantially the same manner as the illumination light communication device 60 described above, and based on this detection result. Thus, a feedback control method can be used. Alternatively, a method of obtaining an integrated value of the second pulse signal supplied to the light source 106 and performing feedback control based on the integrated value can be used in substantially the same manner as the illumination light communication device 80 described above.

  FIG. 12 shows a more specific example of the illumination light communication apparatus 100 according to the fourth embodiment of the present invention. 12 includes a pulse signal generation circuit 111, an adjustment pulse generation circuit 112, an amplifier 113, a pulse addition circuit 114, a white light emitting diode (white LED) 115, a light receiving element 116, an integration circuit 117, a reference value. An output circuit 118 and a comparator 119 are provided.

  The operation of the illumination light communication device 110 is as follows. When communication information is sent from the information source, the pulse signal generation circuit 111 generates a pulse signal P41 corresponding to the communication information. Further, the adjustment pulse generation circuit 112 generates an adjustment pulse signal P42. The amplifier 113 amplifies the adjustment pulse signal P42. Then, the pulse adding circuit 114 generates the pulse signal P43 by adding the amplified adjustment pulse signal P42 to the pulse signal P41.

  FIG. 13 shows a waveform of a pulse signal P43 obtained by adding the adjustment pulse signal P42 to the pulse signal P41. The pulse signal P41 is, for example, a signal whose amplitude becomes a high level and a low level corresponding to the codes “1” and “0” in the communication information. On the other hand, the frequency, duty ratio, and length (total signal length of one unit) of the adjustment pulse signal P42 are determined in advance as initial values, and are constant, for example. However, the amplitude of the adjustment pulse signal P42 changes due to a change in the amplification factor of the amplifier 113. The reception period in FIG. 13 corresponds to the reception blank 53 in FIG.

  Such a pulse signal P43 is supplied from the pulse addition circuit 114 to the white light emitting diode 115. The white light emitting diode 115 emits illumination light modulated by the pulse signal P43, that is, illumination light whose brightness changes in accordance with the waveform of the pulse signal P43.

  Subsequently, the light receiving element 116 receives the illumination light emitted from the white light emitting diode 115, generates an electrical signal whose amplitude changes according to the intensity of the illumination light, and supplies the electrical signal to the integration circuit 117. The integration circuit 117 generates an integrated value per predetermined period (for example, about 0.5 to 1 second) of the electric signal, and supplies the integrated value to one input terminal of the comparator 119. A predetermined reference value is input from the reference value output circuit 118 to the other input terminal of the comparator 119. The comparator 119 compares the integrated value supplied from the integrating circuit 117 with a reference value, and supplies a DC control signal having a voltage corresponding to the difference between the two to the amplifier 113.

  The amplifier 113 changes the amplification factor according to the voltage of this control signal. As a result, the amplitude of the adjustment pulse signal P42 changes according to the voltage of the control signal, that is, the difference between the integrated value supplied from the integrating circuit 117 and the predetermined reference value. More specifically, when the integrated value supplied from the integrating circuit 117 is larger than a predetermined reference value, the voltage of the control signal supplied from the comparator 119 to the amplifier 113 becomes negative, which causes the amplifier 113 to Gain is reduced. Therefore, the amplitude of the adjustment pulse signal P42 is reduced, and as a result, the amount of illumination light per predetermined period is reduced. On the other hand, when the integral value supplied from the integration circuit 117 is smaller than a predetermined reference value, the voltage of the control signal supplied from the comparator 119 to the amplifier 113 becomes positive, thereby increasing the amplification factor of the amplifier 113. Therefore, the amplitude of the adjustment pulse signal P43 increases, and as a result, the amount of illumination light per predetermined period increases. By repeating such an operation, the light quantity per predetermined period of the illumination light converges to a constant light quantity.

  The communication device that has received the illumination light emitted from the illumination light communication device 110 acquires a signal corresponding to the pulse signal P43 from the illumination light, removes the signal corresponding to the adjustment pulse signal P42 from this signal, Only the signal corresponding to the signal P41 is extracted. Such an extraction process can be realized as follows, for example. That is, the timing (interval) for adding the adjustment pulse signal P42 to the pulse signal P41 and the length of the adjustment pulse signal P42 per unit in the illumination light communication apparatus 110 are determined in advance. Accordingly, the communication device can specify the signal corresponding to the adjustment pulse signal P42 from the signal corresponding to the pulse signal P43 under a state in which the illumination light communication device 110 and the communication device are synchronized. It becomes possible. Therefore, the communication device can extract only the signal corresponding to the pulse signal P41 from the signal corresponding to the pulse signal P43, and can reproduce the communication information from this signal.

  As described above, in the illumination light communication apparatuses 100 and 110, the adjustment pulse signal is added to the pulse signal corresponding to the communication information, and the illumination light is modulated by the pulse signal to which the adjustment pulse signal is added. Then, the amplitude of the adjustment pulse signal is changed so that the amount of illumination light per predetermined period is constant. Thereby, the light quantity per predetermined period of illumination light can be made substantially constant. Therefore, the brightness (luminance) of illumination light can be stabilized, and flickering of illumination light that can be directly recognized by humans can be reduced.

  Further, the illumination light communication apparatuses 100 and 110 employ a configuration in which an adjustment pulse signal is added to a pulse signal corresponding to communication information. Thereby, the light quantity of illumination light can be set and adjusted in a wide range by arbitrarily setting and adjusting initial values such as the amplitude, frequency, duty ratio, and length of the adjustment pulse signal. Therefore, the range of setting / adjustment of the brightness of the illumination can be widened, and it is possible to realize an illumination in which the brightness can be freely controlled.

  In addition, in the illumination light communication apparatuses 100 and 110 described above, the configuration in which the amplitude of the adjustment pulse signal is changed so that the amount of illumination light is constant is adopted, but the present invention is not limited to this. For example, the frequency, duty ratio, or length of the adjustment pulse signal may be changed so that the amount of illumination light is constant.

  In FIG. 11, the modulation unit 101 is a specific example of the modulation unit, and the light amount control unit 104 is a specific example of the light amount control unit. The pulse signal generation unit 102 is a specific example of the pulse signal generation unit, the adjustment pulse addition unit 103 is a specific example of the adjustment pulse addition unit, and the adjustment pulse signal control unit 105 is a specific example of the adjustment pulse signal control unit. is there. In FIG. 12, the pulse signal generation circuit 111 is a specific example of the pulse signal generation means. The white light emitting diode 115 is a specific example of the light source. The adjustment pulse generation circuit 112 and the pulse addition circuit 114 are specific examples of adjustment pulse addition means. The light receiving element 116, the integration circuit 117, the reference value output circuit 118, the comparator 119, and the amplifier 113 are specific examples of the adjustment pulse signal control means.

(Fifth embodiment)
FIG. 14 shows a fifth embodiment of the illumination light communication apparatus of the present invention. In the illumination light communication apparatus 120 in FIG. 14, the pulse of the pulse signal for modulating the illumination light is divided into subdivided pulses. Then, the number of subdivided pulses is changed so that the amount of illumination light per predetermined period is constant.

  That is, in the illumination light communication apparatus 120, the modulation unit 121 includes a pulse signal generation unit 122 and a pulse division unit 123. The light amount control unit 124 includes a pulse number control unit 125.

  The operation of the illumination light communication device 120 is as follows. When communication information is sent from the information source, the pulse signal generator 122 generates a pulse signal P51 corresponding to the communication information. Subsequently, the pulse dividing unit 123 divides the pulse (on pulse) of the pulse signal P51 generated by the pulse signal generating unit 122 into a plurality of subdivided pulses having a width smaller than the minimum width of the pulse of the pulse signal P51. Thereby, the pulse signal P53 is generated. The light source 126 emits illumination light whose brightness changes corresponding to the waveform of the pulse signal P53.

  The adjustment pulse signal control unit 105 changes the number of subdivided pulses of the pulse signal P53 so that the amount of illumination light emitted from the light source 106 per predetermined period is constant. As a method of changing the number of subdivided pulses of the pulse signal P53 in order to make the light quantity constant, the light quantity of the illumination light emitted from the light source 126 is detected and detected in substantially the same manner as the illumination light communication apparatus 60 described above. A method of performing feedback control based on the result can be used. Alternatively, a method of obtaining an integral value of the pulse signal P53 supplied to the light source 126 and performing feedback control based on the integral value can be used in substantially the same manner as the illumination light communication device 80 described above.

  FIG. 15 shows a pulse signal P51 generated by the pulse signal generator 122, a pulse signal P52 divided by the pulse divider 123, and a pulse signal P53 in which the number of divided pulses is changed by the pulse number controller 125. Yes.

  The pulse dividing unit 123 divides the pulse W1 of the pulse signal P51 into divided pulses W2 having a width smaller than one half of the minimum pulse width of the pulse signal P51, for example.

  When the amount of illumination light is larger than the predetermined reference amount, the pulse number control unit 125 reduces the number of divided pulses W2 of the pulse signal P52. At this time, as in a pulse signal P53 shown in FIG. 15, at least a divided pulse (first divided pulse W2a) positioned at the rising portion of the pulse W1 and a divided pulse (end divided pulse W2b) positioned at the falling portion of the pulse W1. ) And remain. That is, the pulse number control unit 125 reduces the number of divided pulses W2 existing between the leading divided pulse W2a and the trailing divided pulse W2b. As a result, in the communication device that communicates with the illumination light communication device 120, the signal corresponding to the pulse signal P51 can be easily and accurately restored based on the signal corresponding to the pulse signal P53. That is, based on the illumination light modulated by the pulse signal P53, the signal corresponding to the pulse signal P51 can be restored easily and with high accuracy, so that communication information can be reproduced easily and with high accuracy. become.

  As described above, in the illumination light communication apparatus 120, the pulse of the pulse signal for modulating the illumination light is divided into subdivided pulses, and the number of subdivided pulses is set so that the light quantity per predetermined period of the illumination light is constant. Change. Thereby, the light quantity per predetermined period of illumination light can be made substantially constant. Therefore, the brightness (luminance) of illumination light can be stabilized, and flickering of illumination light that can be directly recognized by humans can be reduced. As a result, when the illumination light communication device 1 is applied to an indoor lighting device (see FIG. 2), an illuminating lamp (see FIG. 3), etc., the original performance as these illuminations, that is, light is applied to the object to make it brighter, The performance of maintaining the brightness can be maintained or improved.

In FIG. 14, the modulation unit 121 is a specific example of the modulation unit, and the light amount control unit 124 is a specific example of the light amount control unit. The pulse signal generation unit 122 is a specific example of the pulse signal generation unit, the pulse division unit 123 is a specific example of the pulse division unit, and the pulse number control unit 125 is a specific example of the pulse number control unit.
In the illumination light communication apparatus described above, the configuration in which the amplitude of the pulse signal or the adjustment pulse signal is changed so that the amount of illumination light is constant has been described, but the present invention is not limited to this. For example, a DC offset may be applied and appropriately changed so that the amount of illumination light is constant.
In addition, the amount of illumination light for each predetermined period can be made constant by adjusting the potential of the pulse signal in the low level period. Further, it goes without saying that the adjustment of the potential during the high level period of the pulse signal may also be performed.

  Further, the present invention can be appropriately changed within a scope not departing from the gist or idea of the present invention that can be read from the claims and the entire specification, and the illumination light communication apparatus and the illumination light communication method, and the like, accompanied by such changes A computer program for realizing the above functions is also included in the technical idea of the present invention.

  The illumination light communication apparatus and the illumination light communication method according to the present invention can be used for illumination light communication in which information is communicated using illumination light, for example. Further, for example, it can be used for an illumination light communication device or the like that is mounted on or can be connected to various computer equipment for consumer use or business use.

Claims (5)

An illumination light communication device that communicates information via illumination light,
A light source that emits illumination light that is visible light;
Modulation means for modulating illumination light emitted from the light source based on the information;
A light amount control unit that controls light emission by the light source so that the light amount per predetermined period of the illumination light modulated by the modulation unit is constant ,
The modulating means includes
Pulse signal generating means for generating a first pulse signal corresponding to the information represented by a binary code;
Adjusting pulse adding means for generating a second pulse signal by adding an adjusting pulse signal to the first pulse signal generated by the pulse signal generating means,
The light source emits illumination light whose brightness changes corresponding to the waveform of the second pulse signal,
The illumination light communication apparatus , wherein the light amount control means includes adjustment pulse signal control means for changing an amplitude, a duty ratio, or a length of the adjustment pulse signal . The illumination light communication apparatus according to claim 1 , wherein the light amount control unit controls generation of illumination light by the light source or modulation of illumination light by the modulation unit. The illumination light communication apparatus according to claim 1 , wherein the light source is a light emitting diode. An illumination light communication method for communicating information via illumination light that is visible light emitted from a light source,
A modulation step of modulating the illumination light based on the information;
A light amount control step for controlling light emission in the light source so that the light amount per predetermined period of the illumination light modulated in the modulation step is constant ,
The modulation step includes
A pulse signal generation step of generating a first pulse signal corresponding to the information represented by a binary code;
An adjustment pulse adding step of generating a second pulse signal by adding an adjustment pulse signal to the first pulse signal generated by the pulse signal generation step,
The light source emits illumination light whose brightness changes corresponding to the waveform of the second pulse signal,
The illumination light communication method , wherein the light amount control step includes an adjustment pulse signal control step of changing an amplitude, a duty ratio, or a length of the adjustment pulse signal . A computer program for causing a computer to function in the illuminating light communication device according as the light quantity control means to one of claims the first term to the third term.

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