Abstract:
Disclosed herein is a solar cell system including: a plurality of power generation panels that differ in the range of wavelengths of light they absorb from each other and convert light into power; a voltage detection section adapted to detect the voltage of power generated by each of the plurality of power generation panels; a reproduction section adapted to compare the voltages of the plurality of power generation panels detected by the voltage detection section so as to reproduce an audio or music signal appropriate to the comparison result; and an output section adapted to output audio or music reproduced by the reproduction section.

Description:
BACKGROUND 
       [0001]    The present disclosure relates to a solar cell system, and more particularly, to a solar cell system capable of outputting audio or music appropriate to environmental light with a simple configuration. 
         [0002]    Solar cells or photoelectric conversion elements adapted to convert sunlight into electric energy use sunlight as a source of energy, making their impact on the global environment extremely small and raising expectations for more widespread use. Crystalline silicon-based solar cells using monocrystalline or polycrystalline silicon and amorphous silicon-based solar cells have been primarily used to date. 
         [0003]    Recent years have seen progress in the commercialization of dye sensitized solar cells using organic dyes. Dye sensitized solar cells can be manufactured at lower cost and with lower energy than silicon-based solar cells. In addition, dye sensitized solar cells use a plastic sheet, making them flexible. Moreover, selection of a dye allows for these solar cells to have a variety of colors. Dye sensitized solar cells differ in the range of wavelengths of light they absorb depending on the organic dye used. 
         [0004]    For example, the present applicant has proposed an apparatus operable to perform a process according to the color of environmental light or the type of illumination by taking advantage of the above characteristics of a dye sensitized solar cell and without using any dedicated sensor (refer, for example, to Japanese Patent Laid-Open No. 2008-20253). 
       SUMMARY 
       [0005]    Efforts are in progress to commercialize dye sensitized solar cells as described above, and hopes are pinned on various examples of application taking advantage of the characteristics of these solar cells. For example, an apparatus is sought after which is capable of outputting audio or music appropriate to environmental light with a simple configuration. 
         [0006]    The present disclosure has been made in light of the foregoing, and it is desirable to be able to output audio or music appropriate to environmental light with a simple configuration. 
         [0007]    A solar cell system according to a mode of the present disclosure includes a plurality of power generation panels, a voltage detection section, a reproduction section and an output section. The plurality of power generation panels differ in the range of wavelengths of light they absorb from each other and convert light into power. The voltage detection section detects the voltage of power generated by each of the plurality of power generation panels. The reproduction section compares the voltages of the plurality of power generation panels detected by the voltage detection section, reproducing an audio or music signal appropriate to the comparison result. The output section outputs the audio or music reproduced by the reproduction section. 
         [0008]    In the mode of the present disclosure, the voltage of power generated by each of the plurality of power generation panels is detected. The plurality of power generation panels differ in the range of wavelengths of light they absorb and convert light into power. The detected voltages of the plurality of power generation panels are compared. The audio or music signal appropriate to the comparison result is reproduced, thus outputting audio or music. 
         [0009]    In the mode of the present disclosure, audio or music appropriate to environmental light can be output with a simple configuration. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIGS. 1A and 1B  are diagrams illustrating a configuration example of an embodiment of a solar cell system to which the present disclosure is applied; 
           [0011]      FIG. 2  is a block diagram illustrating a configuration example of the solar cell system; and 
           [0012]      FIG. 3  is a diagram illustrating the sunlight spectra. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0013]    A detailed description will be given below of a specific embodiment to which the present disclosure is applied with reference to the accompanying drawings. 
         [0014]      FIGS. 1A and 1B  are diagrams illustrating a configuration example of an embodiment of a solar cell system to which the present disclosure is applied.  FIG. 1A  illustrates a perspective view of a solar cell system  11 , and  FIG. 1B  illustrates a plan view of the same system  11 . 
         [0015]    As illustrated in  FIGS. 1 , the solar cell system  11  includes four power generation panels  12 R,  12 G,  12 B- 1  and  12 B- 2 , four piezoelectric elements  13 - 1  to  13 - 4  and a control unit  15 . 
         [0016]    The power generation panels  12 R,  12 G,  12 B- 1  and  12 B- 2  generate power by absorbing sunlight. Power generated by the power generation panels  12 R,  12 G,  12 B- 1  and  12 B- 2  is supplied to the control unit  15 . Dye sensitized solar cells can be used as the power generation panels  12 R,  12 G,  12 B- 1  and  12 B- 2 . 
         [0017]    A dye sensitized solar cell typically includes a dye sensitized porous semiconductor layer and counter electrode that are opposed to each other. The dye sensitized porous semiconductor layer is formed on a transparent conductive substrate by causing a porous semiconductor layer such as titanium oxide to carry a sensitizing dye. The counter electrode is obtained by forming, for example, a platinum layer on a substrate. The outer peripheries thereof are sealed with a sealant. An electrolyte containing redox species such as iodine or iodide ions is filled between the two electrodes. On the other hand, among common red-based sensitizing dyes are ruthenium complex (N719) {=cis-bis(isothiocyanato)-N,N-bis(2,2′-bipyridyl-4,4′-dicarboxylato)-ruthenium(II)}, merocyanines (D149) {=5-[[4-[4-(2,2-diphenylethenyl)phenyl]-1,2,3,3a,4,8b-hexahydrocyclopent[b]indol-7-yl]-methylene]-2-(3-ethyl-4-oxo-2-thioxo-5-thiazolidinylidene)-4-oxo-Thiazolidineacetic acid}, porphyrins (TCPP) {=Tetrakis(4-carboxyphenyl)porphyrin}, xanthene-based dyes {=Rhodamine  6G} and fluorescein- or xanthene-based dyes {rose bengal}. 
         [0018]    Further, among common green-based sensitizing dyes are squarylium-based dyes, croconium-based dyes, copper phthalocyanine {=phthalocyanines} and ruthenium complex (black dye) {tris(isothiocyanato)-ruthenium(II)-2,2′:6′,2″-terpyridine-4,4′,4″-tricarboxylic acid}. Among common blue-based sensitizing dyes are squarylium-based dyes and cyanine-based dyes. Among common yellow-based sensitizing dyes are cyanine-based dye (D131) {=2-Cyano-3-[4-[4-(2,2-diphenylethenyl)phenyl]-1,2,3,3a,4,8b-hexahydrocyclopent[b]indol-7-yl]-2-propenoic acid}, coumarin-based dye {=coumarin 343} and stilbene-based dyes. 
         [0019]    For example, the power generation panel  12 R absorbs the wavelengths of sunlight other than red to generate power. The power generation panel  12 G absorbs the wavelengths of sunlight other than green to generate power. The power generation panels  12 B- 1  and  12 B- 2  absorb the wavelengths of sunlight other than blue to generate power. 
         [0020]    As illustrated in  FIG. 1 , the power generation panels  12 R,  12 G,  12 B- 1  and  12 B- 2  of the solar cell system  11  are arranged so that each of the four panels forms one of the four sides of a cube. Sunlight irradiated onto each side is used to generate power. 
         [0021]    The piezoelectric elements  13 - 1  to  13 - 4  vibrate as they are supplied with power from the control unit  15 . The piezoelectric element  13 - 1  is affixed to the power generation panel  12 B- 1  and vibrates the same panel  12 B- 1 , and the piezoelectric element  13 - 2  is affixed to the power generation panel  12 B- 2  and vibrates the same panel  12 B- 2 . Further, the piezoelectric element  13 - 3  is affixed to the power generation panel  12 R and vibrates the same panel  12 R, and the piezoelectric element  13 - 4  is affixed to the power generation panel  12 G and vibrates the same panel  12 G. 
         [0022]    As described above, the power generation panels  12 R,  12 G,  12 B- 1  and  12 B- 2  serve as vibration plates thanks to the piezoelectric elements  13 - 1  to  13 - 4  affixed thereto and produce a sound as a result of the vibration of the same elements  13 - 1  to  13 - 4 . 
         [0023]    The control unit  15  operates on power supplied from the power generation panels  12 R,  12 G,  12 B- 1  and  12 B- 2 . For example, the control unit  15  supplies power to the piezoelectric elements  13 - 1  to  13 - 4  based on the power output of each of the power generation panels  12 R,  12 G,  12 B- 1  and  12 B- 2 , thus vibrating the same panels  12 R,  12 G,  12 B- 1  and  12 B- 2 . 
         [0024]    The solar cell system  11  configured as described above is used as an audio or music source adapted to output set audio or music according to the power output of each of the power generation panels  12 R,  12 G,  12 B- 1  and  12 B- 2 . 
         [0025]    A detailed description will be given below of the functions of the solar cell system  11  with reference to  FIG. 2 . 
         [0026]    The sections other than the power generation panels  12 R,  12 G,  12 B- 1  and  12 B- 2  and piezoelectric elements  13 - 1  to  13 - 4  illustrated in  FIG. 2  are housed in the control unit  15  ( FIG. 1B ). That is, the solar cell system  11  includes four capacitors  21 - 1  to  21 - 4 , switch  22 , A/D (Analog/Digital) conversion section  23 , voltage conversion section  24 , secondary cell  25 , power amplification section  26 , storage section  27  and arithmetic processing section  28 . 
         [0027]    The capacitors  21 - 1  to  21 - 4  are connected respectively between the terminals of the power generation panels  12 R,  12 G,  12 B- 1  and  12 B- 2 . That is, the capacitor  21 - 1  is connected between the terminals of the power generation panel  12 B- 1 , and the capacitor  21 - 2  is connected between the terminals of the power generation panel  12 B- 2 . Further, the capacitor  21 - 3  is connected between the terminals of the power generation panel  12 R, and the capacitor  21 - 4  is connected between the terminals of the power generation panel  12 G. 
         [0028]    The power generation panels  12 R,  12 G,  12 B- 1  and  12 B- 2  are connected in series with each other. Each of the wires between the output terminals of the power generation panels  12 R,  12 G,  12 B- 1  and  12 B- 2  is connected to the switch  22 . The switch  22  changes the connection between the wires from the power generation panels  12 R,  12 G,  12 B- 1  and  12 B- 2  and the A/D conversion section  23  as appropriate. The A/D conversion section  23  converts the input voltage (analog level) into a digital level. 
         [0029]    For example, if the switch connects the output terminals of the power generation panel  12 B- 1  and the A/D conversion section  23 , the same section  23  outputs the digital voltage level indicating the voltage of the power generated by the power generation panel  12 B- 1  (hereinafter referred to as the power output voltage level as appropriate). Further, if the switch  22  connects the output terminals of the power generation panel  12 B- 2  and the A/D conversion section  23 , the same section  23  outputs the power output voltage level of the power generation panel  12 B- 2 . Similarly, the A/D conversion section  23  outputs the power output voltage levels of the power generation panels  12 R and  12 G. 
         [0030]    The voltage conversion section  24  converts the power generated by each of the power generation panels  12 R,  12 G,  12 B- 1  and  12 B- 2  into power at the specified voltage. For example, the voltage conversion section  24  converts the power into that at the voltage at which the power can be stored in the secondary cell  25 . On the other hand, power generated by the power generation panels  12 R,  12 G,  12 B- 1  and  12 B- 2  is supplied to the power amplification section  26  via the voltage conversion section  24 . 
         [0031]    The secondary cell  25  is, for example, a lithium-ion storage cell and stores power generated by the power generation panels  12 R,  12 G,  12 B- 1  and  12 B- 2 . Further, power stored in the secondary cell  25  is supplied as appropriate to the power amplification section  26 . 
         [0032]    The power amplification section  26  amplifies the signal supplied from the arithmetic processing section  28  and supplies the amplified signal to the piezoelectric elements  13 - 1  to  13 - 4 , thus vibrating the same elements  13 - 1  to  13 - 4 . This allows for the piezoelectric elements  13 - 1  to  13 - 4  to vibrate according to the signal supplied from the arithmetic processing section  28 . 
         [0033]    The storage section  27  is, for example, a flash memory (e.g., EEPROM (Electronically Erasable and Programmable Read Only Memory)) and stores an audio or music signal. 
         [0034]    The arithmetic processing section  28  is driven by power supplied from the secondary cell  25 , reading the audio or music signal from the storage section  27  and supplying the reproduced audio or music signal (analog signal) to the power amplification section  26 . That is, the audio or music signal reproduced by the arithmetic processing section  28  is amplified by the power amplification section  26 , allowing for each of the piezoelectric elements  13 - 1  to  13 - 4  to vibrate the power generation panels  12 R,  12 G,  12 B- 1  and  12 B- 2  according to the amplified signal. As a result, audio or music is output from the power generation panels  12 R,  12 G,  12 B- 1  and  12 B- 2 . 
         [0035]    On the other hand, the arithmetic processing section  28  is supplied with the power output voltage levels of the power generation panels  12 R,  12 G,  12 B- 1  and  12 B- 2  from the A/D conversion section  23 . The arithmetic processing section  28  compares the voltage levels of the same panels  12 R,  12 G,  12 B- 1  and  12 B- 2  and determines, based on the comparison result, the audio or music to be reproduced. 
         [0036]    In general, the maximum amplitude is found at different wavelengths of light for morning, noon and evening in the sunlight spectra as illustrated in  FIG. 3 . In  FIG. 3 , the horizontal axis represents the wavelength, and the vertical axis the spectral intensity. The sunlight spectrum in the morning is shown by a solid line, that in the afternoon by a dashed line, and that in the evening by a long dashed short dashed line. Comparing the maximum amplitudes at different wavelengths of sunlight, we find that the wavelength at which the amplitude is maximal in the afternoon is shorter than that at which the amplitude is maximal in the morning, and that the wavelength at which the amplitude is maximal in the morning is shorter than that at which the amplitude is maximal in the evening. 
         [0037]    As described above, the power generation panels  12 R,  12 G,  12 B- 1  and  12 B- 2  absorb light at different wavelengths to generate power. Therefore, the arithmetic processing section  28  can identify the spectra of sunlight irradiated onto the solar cell system  11  in a simplified manner by comparing the power output voltage levels. The same section  28  can determine based on the identification result in which time zone, namely, morning, afternoon or evening, it is now. 
         [0038]    Audio or music to be reproduced for each time zone is set in the arithmetic processing section  28 . The same section  28  reproduces the audio or music appropriate to the time zone determined based on the identification result of the sunlight spectra according to the settings. It should be noted that these settings can be changed as desired. 
         [0039]    As described above, the solar cell system  11  can be driven only by power generated by the power generation panels  12 R,  12 G,  12 B- 1  and  12 B- 2 . As a result, no commercial power is used for the solar cell system  11 , making it easy to install without any restrictions on installation location. Further, the power generation panels  12 R,  12 G,  12 B- 1  and  12 B- 2  serve as vibration plates in the solar cell system  11 , making the apparatus operable to output audio or music appropriate to environmental light simpler in configuration and more compact than a system using a speaker. 
         [0040]    For example, the solar cell system  11  can be used as an audio generator for use where there is no commercial power. 
         [0041]    The solar cell system  11  can identify the spectra of sunlight based on the power output voltage levels of the power generation panels  12 R,  12 G,  12 B- 1  and  12 B- 2 . Therefore, it is possible to determine in which time zone such as morning, afternoon or evening it is now without separately having a sensor adapted to detect the condition of sunlight. This allows for the solar cell system  11  to reproduce audio or music appropriate to the time zone. 
         [0042]    On the other hand, in a solar cell system using silicon, for example, the power generation elements may not be colored. Therefore, color filters are used to identify the spectra of sunlight in the same manner as the solar cell system  11 . Therefore, there is a concern that a solar cell system using silicon may lead to a decline in power generation efficiency and increased cost of the system as a result of use of color filters. In contrast, the solar cell system  11  uses dye sensitized solar cells as the power generation panels  12 R,  12 G,  12 B- 1  and  12 B- 2 . Therefore, there is no such concern. 
         [0043]    It should be noted that the power generation panels included in the solar cell system  11  are not limited to the four power generation panels  12 R,  12 G,  12 B- 1  and  12 B- 2 . For example, the solar cell system  11  may include four or more power generation panels or a different combination of colors for the power generation panels. 
         [0044]    Further, dye sensitized solar cells adapted to absorb light in the ultraviolet and infrared range, for example, may be used as the power generation panels making up the solar cell system  11 . This makes it possible to detect the condition of sunlight irradiated onto the solar cell system  11  in an even more detailed manner. As a result, the weather can be determined, for example, by the arithmetic processing section  28 . 
         [0045]    For example, when both levels of ultraviolet and infrared radiation are high, it is determined that the weather is fine. When the level of infrared radiation is lower than that of ultraviolet radiation, it is determined that the weather is cloudy. When both levels of ultraviolet and infrared radiation are low, it is determined that it is twilight. The arithmetic processing section  28  reproduces audio or music based on these determinations. Further, the arithmetic processing section  28  can, for example, reproduce audio or music (e.g., switch to a different piece of music) appropriate to surrounding environmental light as when it is bright or dark in the surroundings. 
         [0046]    Further, if the solar cell system  11  includes, for example, a communication section, the arithmetic processing section  28  can change the data (audio or music signal) stored in the storage section  27  using the communication section via a network. Similarly, the arithmetic processing section  28  can change the settings (those associated with the time zones, weather conditions and others) for audio and music to be reproduced. 
         [0047]    It should be noted that flat plates may be vibrated to output audio or a speaker may be incorporated in the solar cell system  11  to output audio from the speaker rather than vibrating the power generation panels with the piezoelectric elements  13 - 1  to  13 - 4 . 
         [0048]    Further, the term “system” in the present specification refers to an apparatus as a whole which includes a plurality of devices. 
         [0049]    It should be noted that the embodiment according to the present disclosure is not limited to that described above but may be modified in various manners without departing from the scope of the present disclosure. 
         [0050]    The present disclosure contains subject matter related to that disclosed in Japanese Priority Patent Application JP 2010-144387 filed in the Japan Patent Office on Jun. 25, 2010, the entire content of which is hereby incorporated by reference.