Patent Publication Number: US-2012025838-A1

Title: Sunlight simulator

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention generally relates to a sunlight simulator and solar cell measuring device consisting of detecting device; in particular, the present invention relates to a sunlight simulator or a solar cell measuring device internally equipped with a detecting device thereby monitoring the irradiation intensity of a beam emitted by an internal light source. 
     2. Description of Related Art 
     At present, the solar cell power generation system is produced by means of semiconductor processes, whose power generation principle lies in that solar daylight is allowed to radiate on the solar cell such that the solar cell absorbs the incident sunlight energy thereby generating electron to create current due to semiconductor features, and transferring the created current to the load via conducting lines. 
     Therefore, after completion of solar cell manufacture processes, it is required to evaluate the performance of power generation capability in the solar cell. In case the fabricated solar cell demonstrates good conversion output features, the solar cell manufacturer can exploit more competitive price advantage in market; but the determination for such output features essentially follows the photoelectric conversion efficiency 
     
       
         
           
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     where V indicates voltage at the maximum output power, I indicates current at the maximum output power and P indicates value of the maximum output power) which is obtained by measuring the current-voltage curve of the solar cell subject to sunlight exposure. The conversion efficiency in the solar cell represents a ratio of the energy collected by photoelectric conversions from sunlight to electricity against the energy from sunlight radiation within one day; for example, at noon from March to September, the solar radiation energy at a location near the equator of earth is measured approximately 1000 W/m 2 , so the standard solar radiation energy (i.e. AM1.5G) may generate the energy of 1000 W/m 2 ; hence for a solar cell having an area of 1 meter squared and featuring the conversion efficiency of 15%, a peak energy of roughly 150 Watts can be thus generated at noon in March or September along the equator. 
     Consequently, measurement of the power generation feature in solar cells is crucial; whereas the irradiation of sunlight may fluctuate due to many factors like variations in sunlight radiation caused by weather changes and so on, the industry thus typically uses a sunlight simulator  101  to simulate the required sunlight. In operation, a simulated beam  1011  is respectively projected onto a solar cell  102  under measurement and a monitor cell  103  located outside of the sunlight simulator  101  in order to perform the output feature measurement on the solar cell  102  under measurement; the externally installed monitor cell  103  is used to perform the irradiation measurement on the beam so as to monitor the intensity thereof (see  FIG. 1 ). 
     However, in the above-mentioned beam irradiation measurement, since it is necessary to simultaneously project the beam onto the solar cell under measurement and the monitor cell, such an operation needs at least two opening gates or otherwise one single bigger opening gate, thus consequently, forcing the sunlight simulator to use an internal light source of higher power so as to provide sufficiently uniform light radiation onto both the solar cell under measurement and the monitor cell, which adversely affects the output feature of the solar cell. In addition, since the price for such a type of light source may be proportional to the effective brightness and illumination area thereof, the manufacture cost becomes a disadvantageous factor in such an approach. 
     As a result, it is desirable to provide a solution of a sunlight simulator or solar cell measuring device having beam irradiation measuring device internally installed which allows to advantageously reduce the required manufacture cost of light source in an automatic field. 
     SUMMARY OF THE INVENTION 
     An objective of the present invention is to provide a sunlight simulator and solar cell measuring device consisting of detecting device wherein a detecting device for beam irradiation measurement is installed inside of the sunlight simulator. 
     Another objective of the present invention is to provide a sunlight simulator and solar cell measuring device consisting of detecting device wherein a detecting device for beam irradiation measurement is installed inside of the solar cell measuring device. 
     Yet another objective of the present invention is to provide a sunlight simulator and solar cell measuring device consisting of detecting device which allows to reduce the range of the opening gate and to prevent the use of the high-power light source featuring wider illumination range thereby lessening the manufacture cost for the sunlight simulator or the solar cell measuring device. 
     In order to achieve the objectives set forth as above, a sunlight simulator and solar cell measuring device consisting of detecting device according to the present invention is provided wherein the housing is a closed space consisting of an opening gate, the closed space is internally installed with a light source which is used to emit a light toward the opening gate, and a splitting unit is installed on the travelling path of the light for dividing the light into a first light-beam and a second light-beam, herein the first light-beam is projected toward the opening gate, and a collimating lens can be installed at the location of the opening gate for projecting the first light-beam onto the solar cell under measurement as a solar cell measuring device; in addition, a detecting device is installed on the travelling path of the second light-beam for receiving the second light-beam, then a signal can be outputted by the detecting device in order to monitor the intensity of the light emitted by the light source thereby ensuring the precision of solar cell measurement. 
     Specifically, the aforementioned splitting unit is a planar splitter and the detecting device is a solar cell or a semiconductor chip. 
     Specifically, at least one filter is installed between the above-said light source and detecting device, in which the type of the filter is a filter enabling passing of a particular wavelength or alternatively a filter enabling blocking of ultra-violet (UV) ray. 
     Specifically, an integrating device is installed between the above-said light source and detecting device which allows the light emitted by the light source to become uniform. 
     Specifically, a shutter is installed between the above-said light source and detecting device which enables separation of the light source in case the light source is not in use. 
     Specifically, the above-said light source can be any one of a set of light emitting diodes (LEDs), a xenon lamp, a halogen lamp or a combination thereof, and additionally a condenser is installed on one side of the light source thereby converging the light of the light source. 
     Specifically, a reflecting device is further installed inside of the above-said housing for reflecting out the first light-beam at an angle toward the opening gate. 
     Specifically, the present invention further comprises a conversion efficiency analyzing device which is used to receive the conversion signal outputted by the detecting component and to calculate and compare with a current-voltage (I-V) curve for output. 
     Furthermore, another implementation approach can be also applied in which a transmission detecting device is directly installed on the travelling path of the light of the light source, the surface of the transmission detecting device is installed with a detecting component used to detect light signal and to convert the light signal into a conversion signal for output thereby detecting the irradiation of the light and accordingly eliminating the use of the splitting unit as illustrated in the previous embodiment. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a diagram for the operation of a prior art solar cell measuring device; 
         FIG. 2  shows a diagram for the operation of a first embodiment of a sunlight simulator and solar cell measuring device consisting of detecting device according to the present invention; 
         FIG. 3A  shows a diagram for the structure of a second embodiment of a sunlight simulator and solar cell measuring device consisting of detecting device according to the present invention; 
         FIG. 3B  shows a diagram for the operation of the second embodiment of a sunlight simulator and solar cell measuring device consisting of detecting device according to the present invention; 
         FIG. 3C  shows a diagram for the operation of a third embodiment of a sunlight simulator and solar cell measuring device consisting of detecting device according to the present invention; 
         FIG. 4A  shows a diagram for the operation of a fourth embodiment of a sunlight simulator and solar cell measuring device consisting of detecting device according to the present invention; 
         FIG. 4B  shows a diagram for the operation of a fifth embodiment of a sunlight simulator and solar cell measuring device consisting of detecting device according to the present invention; 
         FIG. 5  shows a diagram for the implementation architecture of a sunlight simulator and solar cell measuring device consisting of detecting device according to the present invention; and 
         FIG. 6  shows a diagram for AM1.5G current-voltage (I-V) curve of a sunlight simulator and solar cell measuring device consisting of detecting device according to the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The aforementioned and miscellaneous technical contents, aspects and effects of the present invention can be hereunder clearly presented by referring to the detailed descriptions for the preferred embodiments of the present invention in conjunction with appended drawings. 
     Refer first to  FIG. 2 , wherein a diagram for the operation of a first embodiment of a sunlight simulator and solar cell measuring device consisting of detecting device according to the present invention is shown. From the Figure, it can be seen that the sunlight simulator comprises: 
     a housing  1 , which is a closed space consisting of an opening gate  11 ; 
     a light source  12 , which is installed inside of the housing  1  for consistently emitting a light  121  toward the opening gate  11  and formed by any one of a set of light emitting diodes (LEDs), a xenon lamp, a halogen lamp or a combination thereof; 
     a splitting unit  13 , which is installed on the travelling path of the light  121  emitted by the light source  12  for dividing the light  121  into a first light-beam  1211  and a second light-beam  1212 , herein the first light-beam  1211  is projected toward the opening gate  11 , and additionally the splitting unit  13  is a planar splitter; 
     a detecting device  14 , which is installed on the travelling path of the second light-beam  1212  for receiving the second light-beam  1212 , then a signal can be outputted by the detecting device  14  in order to monitor the irradiation of the light  121  emitted by the light source  12 , and additionally the detecting device  14  is a solar cell or a semiconductor chip. 
     It should be noticed that a condenser  15  can be installed on one side of the light source  12  thereby converging the light  121  emitted by the light source  12 . 
     Refer next to  FIGS. 3A and 3B , wherein diagrams for the structure and the operation of a second embodiment of a sunlight simulator and solar cell measuring device consisting of detecting device according to the present invention are respectively shown. From these Figures, it can be seen that the solar cell measuring device outputs a simulated light source to a solar cell under measurement  4 , and the solar cell measuring device comprises: 
     a housing  2 , which is a closed space consisting of an opening gate  21 ; 
     a light source  22 , which is installed inside of the housing  2  for consistently emitting a light  221  toward the opening gate  21  and formed by any one of a set of light emitting diodes (LEDs), a xenon lamp, a halogen lamp or a combination thereof; 
     a splitting unit  23 , which is installed on the travelling path of the light  221  emitted by the light source  22  for dividing the light  221  into a first light-beam  2211  and a second light-beam  2212 , and additionally the splitting unit  23  is a planar splitter; 
     a first reflecting device  24 , which is installed inside of the housing  2  for reflecting out the first light-beam  2211  at an angle toward the opening gate  21 ; 
     a detecting device  25 , which is installed on the travelling path of the second light-beam  2212  for receiving the second light-beam  2212 , and then a conversion signal can be outputted by the detecting device  25  in order to monitor the irradiation of the light  221  emitted by the light source  22 ; 
     a collimating lens  26 , which is installed at the location of the opening gate  21  of the housing  2  for projecting the first light-beam  2211  onto the solar cell under measurement  4 . 
     It should be noticed that in case the light source  22  is not installed at a position parallel to the splitting unit  23 , it is possible to additionally place a second reflecting device  27  inside of the housing  2  thereby reflecting out the light  221  emitted by the light source  22  at an angle toward the splitting unit  23  (see  FIG. 3C ). 
     It should be noticed that an air-mass 1.5G (AM1.5G) filter  28  can be installed between the light source  22  and the splitting unit  23  thereby only allowing specific wavelength(s) in the light  221  emitted by the light source  22  to pass through in order to make the spectrum output be close to actual sunlight. Furthermore, “AM1.5G” means the average daylight irradiation of sunlight incident at 45 degrees onto the surface of earth. Consequently, if the solar cell is used at other places, the sunlight incident angle may vary; that is, a filter of different air-mass value (representing the average daylight irradiation of sunlight onto the surface of earth incident at different angle) should be applied. 
     It should be noticed that an ultra-violet (UV) filter  29  can be installed between the light source  22  and the splitting unit  23  thereby eliminating the UV ray in the light  221 . 
     It should be noticed that an integrating device  30  can be installed between the light source  22  and the splitting unit  23  thereby making the light  221  become uniform. 
     It should be noticed that a shutter  31  can be installed between the light source  22  and the splitting unit  23  thereby enabling separation of the light  221  emitted by the light source  22  without shutting down electric power in case the light source  22  is not in use so as to prevent consistent temperature elevation in the component. 
     It should be noticed that a condenser  32  can be installed on one side of the light source  22  thereby converging the light  221  emitted by the light source  22 . 
     Refer now to  FIG. 4A , wherein a diagram for the operation of a fourth embodiment of a sunlight simulator and solar cell measuring device consisting of detecting device according to the present invention is shown. From the Figure, it can be seen that the sunlight simulator comprises: 
     a housing  5 , which is a closed space consisting of an opening gate  51 ; 
     a light source  52 , which is installed inside of the housing  5  for consistently emitting a light  521  toward the opening gate  51  and formed by any one of a set of light emitting diodes (LEDs), a xenon lamp, a halogen lamp or a combination thereof; 
     a transmission detecting device  53 , which is installed on the travelling path of the light  521  emitted by the light source  52  for receiving the light  521  and allows the light  521  to pass through the transmission detecting device  53 . A detecting component is installed on the surface of the transmission detecting device  53  thereby monitoring the irradiation of the light  521  emitted by the light source  52  and converting the light signal into a conversion signal for output. 
     It should be noticed that a first reflecting device  54  can be installed inside of the housing  5  for reflecting out the light  521  passing through the transmission detecting device  53  at an angle toward the opening gate  51 . 
     It should be noticed that a collimating lens  55  can be installed at the location of the opening gate  51  of the housing  5  for projecting the light  521  onto the solar cell under measurement  7 . 
     It should be noticed that in case the light source  52  is not installed at a position parallel to the transmission detecting device  53 , it is possible to additionally place a second reflecting device  56  inside of the housing  5  thereby reflecting out the beam  521  emitted by the light source  52  at an angle toward the transmission detecting device  53  (see  FIG. 4B ). 
     It should be noticed that an air-mass 1.5G (AM1.5G) filter  57  can be installed between the light source  52  and the transmission detecting device  53  thereby only allowing the specific wavelength(s) in the light emitted by the light source to pass through in order to make the spectrum output be close to actual sunlight. 
     It should be noticed that an ultra-violet (UV) filter  58  can be installed between the light source  52  and the transmission detecting device  53  thereby eliminating the UV ray in the light  521 . 
     It should be noticed that an integrating device  59  can be installed between the light source  52  and the transmission detecting device  53  thereby making the light  521  become uniform. 
     It should be noticed that a shutter  60  can be installed between the light source  52  and the transmission detecting device  53  thereby enabling separation of the light  521  emitted by the light source  52  without shutting down electric power in case the light source  52  is not in use, so as to prevent consistent temperature elevation in the component and also prolong the lifespan of the light source  52 , further reducing maintenance requirements and lessening operation costs. 
     It should be noticed that a condenser  61  can be installed on one side of the light source  52  thereby converging the light  521  emitted by the light source  52 . 
     Refer to  FIG. 5 , wherein a block diagram of a preferred application embodiment is shown, illustrating the implementation architecture of a sunlight simulator and solar cell measuring device consisting of detecting device according to the present invention, and obtain results of higher precision in provides by conversion efficiency analyzing device as shown in  FIG. 6 . Herein, after reception of the beam from the light source  81  by the detecting device  82  in either the sunlight simulator or the solar cell measuring device, a detection signal can be consistently outputted through photoelectric conversion to the conversion efficiency analyzing device  9 ; at the same time, after reception of the beam from the light source  81  by the solar cell under measurement  10 , an electrical signal can be also consistently outputted through photoelectric conversion to the conversion efficiency analyzing device  9 . The conversion efficiency analyzing device  9  accordingly calculates the ratio of light source irradiation variation in the light source  81  based on the aforementioned detection signal and the standard I-V curve, then performs operations on the obtained ratio and the electrical signal from the solar cell under measurement  10  in order to compensate or correct the light source irradiation variation in the light source  81  occurring during the lighting process thereby reducing the influence of the light source irradiation variation in the simulator on the measurement; after such a compensation or correction operation, it is possible to reduce one thirds or half of the variation for the conversion efficiency measure values of the solar cell under measurement, further achieving the objectives of platform cost reduction and measure quality enhancement. 
     The disclosed sunlight simulator and solar cell measuring device consisting of detecting device according to the present invention, in comparison with other prior art technologies, provides the following advantages: 
     1. in accordance with the present invention, a detecting device for beam irradiation measurement is installed inside of the sunlight simulator and solar cell measuring device which reduces the size of the opening gate and also lessens manufacture costs of the sunlight simulator or solar cell measuring device; 
     2. in accordance with the present invention, a beam irradiation signal of detection is transferred to a conversion efficiency analyzing device and the conversion efficiency analyzing device performs correction operations in order to increase the measure precision of the solar cell under measurement; 
     3. by mean of such precision improvements, with the pricing standard based on the conversion efficiency of solar cells in current market, the sales price of solar cells after categorization can be advantageously reflected. 
     The descriptions of the aforementioned preferred embodiments according to the present invention are to better illustrate the characteristics and spirit of the present invention, rather than using the above-disclosed preferred embodiments to limit the scope thereof. It is intended that all effectively equivalent changes, alternations or modifications are deemed to be included within the scope of the present invention delineated by the claims set forth as below.