JP2016144253A - Spectral sensitivity measurement device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To highly accurately calculate a spectral sensitivity under any bias light quantity when measuring an absolute spectral sensitivity of a solar cell.SOLUTION: The spectral sensitivity measurement device comprises: a light quantity ratio storage part 60 for storing a ratio of a first light quantity (a light quantity of a bias light) and a second light quantity (a light quantity of a monochromatic light) emitted from first and second light source parts; a combination creation part 62 which calculates a plurality of first light quantities being different from each other and a plurality of corresponding second light quantities while using a value that indicates the ratio, and creates a plurality of combinations; an emission control part 63 which emits the bias light/monochromatic light in accordance with a combination; and a differential spectral sensitivity calculation part 64 for calculating a plurality of differential spectral sensitivities by calculating a differential spectral sensitivity while using a short-circuit current that is measured by a current measurement part, in the state where the solar cell is irradiated with the bias light emitted from the first light source part and the monochromatic light emitted from the second light source part overlapping each other under control of the emission control part 63.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a spectral sensitivity measuring apparatus that measures the absolute spectral sensitivity of a solar cell.

  A solar cell is an element that directly converts light energy into electric power by utilizing the photovoltaic effect, and various solar cells have been researched and developed, and have begun to spread widely in recent years. There are various types of solar cells such as silicon-based solar cells using silicon (Si), compound-based solar cells using a compound semiconductor such as InGaAs, and organic-based solar cells using an organic semiconductor. Unlike silicon-based solar cells, there are organic solar cells having characteristics that the short-circuit current is linear with respect to irradiance and does not change.

  In order to evaluate the performance of the solar cell, for example, there are evaluation methods defined in IEC60904 and JIS (C8905 to C8991). As a method for evaluating the spectral sensitivity of a non-linear solar cell as described above, there is a measurement method for measuring the absolute spectral sensitivity of a solar cell by the DSR method (differential spectral responsivity method) (for example, Patent Document 1 and Non-Patent Documents 1 and 2) reference). Note that IEC is an abbreviation for International Electrotechnical Commission. JIS is an abbreviation for Japan Industrial Standards (Japanese Industrial Standards). In addition, there is a measurement method for measuring the absolute spectral sensitivity of solar cells other than the DSR method (see, for example, Patent Document 2).

Absolute spectral sensitivity and related terms will be described.
(1) The absolute spectral sensitivity of a solar cell means the spectral sensitivity measured under a light source having a spectral irradiance to be measured. Note that the short-circuit current of the solar cell can be calculated by convolving the absolute spectral sensitivity and the absolute value spectral irradiance of the irradiation light.
(2) The short circuit current is a current that flows through the solar cell when the potential difference between the positive electrode and the negative electrode of the solar cell is 0V.
(3) The spectral sensitivity [A / W / m ² / nm] of the solar cell is obtained by dividing the short-circuit current output from the solar cell when the solar cell is irradiated with light of a specific wavelength by the irradiated energy. It is.
(4) The bias light is light (for example, white light) applied to the solar cell in order to flow a certain amount of bias current when measuring the differential spectral sensitivity.
(5) In the DSR method, each differential spectral sensitivity for each bias current is measured by sequentially changing the irradiation energy of the bias light, and the plurality of differential spectral sensitivities thus measured and the spectral irradiance distribution of the irradiation light to be obtained. Thus, the absolute spectral sensitivity of the solar cell is obtained. Details are described in Non-Patent Document 2.
(6) The differential spectral sensitivity is the rate of change of the short-circuit current due to a slight fluctuation in the spectral energy of an arbitrary wavelength in the solar cell based on each bias light. Differential spectral sensitivity measures the short-circuit current in a solar cell (short-circuit current for bias light irradiation), and measures the short-circuit current (short-circuit current for bias light and monochromatic light irradiation) in a state where the irradiation light is further irradiated with monochromatic light with minute irradiation energy. The difference between the short-circuit current for bias light irradiation and the short-circuit current for bias light and monochromatic light irradiation is obtained by dividing by the irradiation energy of monochromatic light.
(7) Monochromatic light is light of an arbitrary wavelength that irradiates the solar cell to measure differential spectral sensitivity. Usually, the energy is adjusted to be sufficiently small with respect to the bias light (white bias light).

International Publication No. 2013/084441 Pamphlet JP 2004-281706 A

“Calibration of solar cells. 1: The differential spectral responsivity method”, 1 May 1987 / Vol. 26 No. 9 Applied Optics IEC 60904-8 Edition 3

  In IEC 60904-8 Edition 3, the spectral sensitivity measurement of a non-linear solar cell whose short-circuit current is not linear with respect to irradiance is required to be obtained by the DSR method.

However, this DSR method assumes that the irradiance of monochromatic light is sufficiently small relative to the irradiance of each bias light. When the large bias irradiance 1000W / m ² is generally also the irradiance of monochromatic light as 1W / m ^2, the change amount of the short-circuit current due to short-circuit current is large monochromatic light by the white light is a slight effect on the measurement accuracy Minor. On the other hand, the DSR method measures each differential spectral sensitivity while changing the bias light from low illuminance to irradiance to be measured, so that when the irradiance of the bias light is, for example, 10 W / m ² , the monochromatic light is obtained. When irradiance of 1 W / m ² is irradiated, the short-circuit current of the solar cell of the object to be measured changes greatly due to the light energy of monochromatic light, and accurate differential spectral sensitivity under low illuminance is not required. There are challenges.

  The present invention provides a spectral sensitivity measuring apparatus capable of obtaining a differential spectral sensitivity with high accuracy under an arbitrary amount of bias light in order to solve the above-described problem in measurement of absolute spectral sensitivity of a solar cell using the DSR method. The purpose is to provide.

  The spectral sensitivity measuring apparatus according to the present invention that achieves the above object includes a first light source unit that emits the bias light by adjusting a light amount of bias light, and emits the monochromatic light by adjusting a light amount of monochromatic light. A second light source unit, a current measurement unit that measures a short-circuit current of the solar cell to be measured, a first light amount that is the light amount of the bias light, and a second light amount that is the light amount of the monochromatic light are predetermined. A light amount ratio storage unit that stores a value indicating the ratio obtained, a bias light amount storage unit that stores a plurality of different first light amounts, and a plurality of the first light amounts stored in the bias light amount storage unit A plurality of the second light amounts corresponding to each of the first light amount and the first light amount corresponding to the first light amount are calculated using a value indicating the ratio stored in the light amount ratio storage unit. Combined work to create multiple combinations with the second light quantity And for each of the plurality of combinations created by the combination creation unit, the first light source unit emits the first light amount of the bias light, and the second light source unit causes the second light source unit to emit the second light. An emission control unit that emits the monochromatic light of a light amount, and the bias light emitted from the first light source unit by the control of the emission control unit for each of the plurality of combinations created by the combination creation unit By calculating the differential spectral sensitivity using the short-circuit current measured by the current measuring unit in a state where the monochromatic light emitted from the second light source unit is superimposed on the solar cell and irradiated to the solar cell, A difference spectral sensitivity calculation unit for obtaining the difference spectral sensitivity of the solar cell, and a plurality of the difference spectral sensitivities obtained by the difference spectral sensitivity calculation unit. Comprising an absolute spectral sensitivity calculating unit for calculating a degree, the.

  The absolute spectral sensitivity measurement of a solar cell using the DSR method includes a step of obtaining a plurality of differential spectral sensitivities by measuring each differential spectral sensitivity with respect to each light amount by sequentially changing the light amount of bias light. In the spectral sensitivity measuring apparatus according to the present invention, by setting the ratio of the light amount of the bias light and the light amount of the monochromatic light in advance, when the light amount of the bias light is large in the above step, the light amount of the monochromatic light is increased. The SN during light measurement is improved, and when the amount of bias light is small, the amount of monochromatic light is reduced. Thereby, for each bias light, the influence of the short-circuit current due to the monochromatic light can be made relatively small with respect to the short-circuit current due to the bias light, and the influence of the fluctuation of the short-circuit current in each irradiance can be eliminated. In the measurement of the absolute spectral sensitivity of the solar cell used, it is possible to obtain the differential spectral sensitivity with high accuracy under an arbitrary amount of bias light.

  In the above-described configuration, the combination creating unit sets the lower limit value for the second light amount that is equal to or less than a predetermined lower limit value among the plurality of second light amounts calculated using the value indicating the ratio. Let it be the second light quantity.

  If the second light amount, which is the light amount of monochromatic light, is less than a certain value, the influence of the short-circuit current due to the monochromatic light on the short-circuit current due to the bias light is negligible, and thus does not cause a large measurement error. On the other hand, when the light amount ratio (value indicating the ratio) is the same regardless of the amount of light of the monochromatic light, if the bias light is small, the SN ratio of the short-circuit current measurement using the monochromatic light is deteriorated. Accordingly, since the difference spectral sensitivity measurement accuracy may be deteriorated, a lower limit is provided for the amount of monochromatic light.

  In the above configuration, the light amount ratio storage unit stores a plurality of values indicating the ratios assigned to the plurality of first light amounts, and the combination creation unit includes a plurality of the first light amounts. A plurality of the second light amounts corresponding to each of the plurality of first light amounts are calculated using a value indicating the ratio assigned to each of the light amounts.

  According to this configuration, since the ratio can be changed according to each of the plurality of first light amounts, the plurality of second light amounts can be set to optimum values.

  That is, the ratios can be made different from each other according to the plurality of first light quantities. For example, a plurality of first light amounts are set as a light amount A, a light amount B, a light amount C, a light amount D, and a light amount E in ascending order. The ratio assigned to the light quantity A is 200: 1, the ratio assigned to the light quantity B is 400: 1, the ratio assigned to the light quantity C is 600: 1, the ratio assigned to the light quantity D is 800: 1, and the ratio assigned to the light quantity E is 1000: 1. To do.

  Further, the plurality of first light amounts may be divided into several groups, and the ratios may be different from each other depending on the group. For example, the ratio assigned to the group of the light quantity A, the light quantity B, and the light quantity C is set to 500: 1, and the ratio assigned to the group of the light quantity D and the light quantity E is set to 1000: 1.

  In the above configuration, the first light source unit includes a first light emitting unit that emits the bias light, and a first adjusting unit that adjusts the amount of the bias light emitted by the first light emitting unit. The spectral sensitivity measuring device further includes the first light amount stored in the bias light amount storage unit with respect to a reference detector in which a short-circuit current and a spectral sensitivity under a predetermined condition are specified. The short-circuit current output from the reference detector in the state where the bias light is irradiated is defined as a first short-circuit current, and the plurality of first light amounts stored in the bias light amount storage unit and the first A first short-circuit current calculation unit that calculates a plurality of the first short-circuit currents corresponding to each of the plurality of first light amounts using a predetermined formula; and the reference detector includes the first short-circuit current. To output the first key The first set value is a value set in the unit, and the short-circuit current measured by the current measurement unit in a state where the reference light is applied to the reference detector is calculated by the first short-circuit current calculation unit. A first set value calculation unit that calculates a plurality of the first set values corresponding to each of the plurality of first short-circuit currents, as compared with each of the plurality of first short-circuit currents that are performed; A first set value storage unit that stores a plurality of the first set values calculated by the first set value calculation unit, and the emission control unit is stored in the first set value storage unit. Each of the plurality of stored first setting values is set in the first adjustment unit, and the bias light is emitted from the first light source unit.

  This configuration defines means for calculating the first set value. As described above, the first set value is a value set in the first adjustment unit so that the reference detector outputs the first short-circuit current. According to this configuration, the setting value for emitting the bias light can be determined based on the current value from the reference detector instead of measuring the irradiance.

  In the above configuration, the second light source unit includes a second light emitting unit, a monochromatic light generating unit that generates the monochromatic light using light emitted by the second light emitting unit, and the monochromatic light generating unit. The spectral sensitivity measuring device further includes the second light amount calculated by the combination creating unit with respect to the reference detector. The short-circuit current output from the reference detector in a state where the monochromatic light is irradiated is set as a second short-circuit current, and the second light amount calculated by the combination creating unit, the second predetermined formula, and the reference A second short-circuit current calculating unit that calculates two or more second short-circuit currents corresponding to two or more monochromatic lights having different wavelengths using the spectral sensitivity of the detector; and the reference detector. Outputs the second short-circuit current Therefore, a value set in the second adjustment unit is set as a second setting value, and the short-circuit current measured by the current measurement unit in a state where the monochromatic light is irradiated on the reference detector is set as the second setting value. The two or more second setting values corresponding to each of the two or more second short-circuit currents are calculated in comparison with each of the two or more second short-circuit currents calculated by the short-circuit current calculation unit. A second set value calculation unit that calculates two or more second short-circuit currents for each of the plurality of second light quantities, and the second short-circuit current calculation unit The set value calculation unit calculates two or more second set values for each of the plurality of second light quantities, and the spectral sensitivity measuring device further calculates the second set value calculation unit. For each of the plurality of second light quantities. The second setting value above is a plurality of the second setting values, and includes a second setting value storage unit that stores the plurality of second setting values, and the emission control unit includes the second setting value. Each of the plurality of second setting values stored in the setting value storage unit is set in the second adjustment unit, and the monochromatic light is emitted from the second light source unit.

  This configuration defines means for calculating the second set value. As described above, the second set value is a value set in the second adjustment unit so that the reference detector outputs the second short-circuit current. According to this configuration, it is possible to determine a setting value for emitting monochromatic light based on the current value from the reference detector rather than measuring the irradiance.

  “Plural” and “2 or more” are integers of 2 or more. Let “plurality” be n, and “two or more” be m. n and m may be the same or different. The second short-circuit current calculating unit calculates n × m (plural) second short-circuit currents, and the second set value calculating unit includes n × m (plural) second set values. Is calculated.

  In the above configuration, the first adjustment unit is at least one of a first diaphragm and a first ND filter, and the second adjustment unit is at least one of a second diaphragm and a second ND filter. is there.

  It can be set to a predetermined light amount by attenuating the light amounts of the bias light and the monochromatic light with an ND filter, a diaphragm or the like. As the first diaphragm, a diaphragm of a type including a first plate member having a plurality of through holes having different aperture ratios can be used. As the second diaphragm, a type of diaphragm including a second plate member having a plurality of through holes having different aperture ratios can be used.

  In the above configuration, the predetermined condition is an STC that is a condition for evaluating the performance of the solar cell.

  In the above configuration, the value indicating the ratio stored in the light amount ratio storage unit is a default value.

  According to this configuration, an operation of inputting a value indicating the ratio to the spectral sensitivity measuring apparatus can be omitted. This is effective when the value indicating the ratio is unknown.

  The above configuration further includes an input unit, and a storage control unit that stores a value input by operating the input unit in the light amount ratio storage unit as a value indicating the ratio.

  According to this configuration, the operator of the spectral sensitivity measuring apparatus can input a desired value to the spectral sensitivity measuring apparatus as a value indicating the ratio.

  In the above configuration, each of the plurality of combinations created by the combination creation unit is emitted from the bias light emitted from the first light source unit and the second light source unit under the control of the emission control unit. And a lock-in amplifier having a function of detecting a short-circuit current due to the monochromatic light from among the short-circuit currents measured by the current measuring unit in a state where the monochromatic light is superimposed on the solar cell. The differential spectral sensitivity calculation unit calculates the differential spectral sensitivity using a short-circuit current generated by the monochromatic light detected by the lock-in amplifier.

  It is possible to extract AC component monochromatic light from the short-circuit current (stationary light) due to the bias light and the short-circuit current (AC light) obtained by chopping the monochromatic light by the lock-in amplifier.

  According to the present invention, in measuring the absolute spectral sensitivity of a solar cell using the DSR method, it is possible to obtain the differential spectral sensitivity with high accuracy under an arbitrary amount of bias light.

It is a graph which shows the 1st example of the relationship between the wavelength of the light (synthetic light) which superimposed white bias light and monochromatic light, and the short circuit current of a solar cell. It is a graph which shows the 2nd example. It is a graph which shows the 3rd example. It is a block diagram which shows the structure of the spectral sensitivity measuring apparatus which concerns on this embodiment. It is explanatory drawing explaining the functional block of the control part with which the spectral sensitivity measuring apparatus which concerns on this embodiment is provided. It is the first half of the flowchart explaining operation | movement of the spectral sensitivity measuring apparatus which concerns on this embodiment. It is the latter half of the flowchart. It is the table | surface which put together various settings used as the premise which measures the absolute spectral sensitivity of a solar cell. It is a flowchart explaining the process of calculating | requiring a 1st setting value. It is a graph which shows the relationship between a wavelength and irradiance about the xenon lamp used as a 2nd light emission part. It is a flowchart explaining the process of calculating | requiring a 2nd setting value.

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

  The cause of the measurement error described in the column of the problem to be solved by the invention will be described. FIG. 1 is a graph showing a first example of the relationship between the wavelength of light (combined light) obtained by superposing white bias light and monochromatic light and the short-circuit current of the solar cell. FIG. 2 is a graph showing the second example. FIG. 3 is a graph showing the third example. 1 to 3, the horizontal axis indicates the wavelength of light obtained by superimposing white bias light and monochromatic light, and the vertical axis indicates the short-circuit current of the solar cell.

  Referring to FIGS. 1 to 3, a hatched area represents a short-circuit current due to monochromatic light, and a hatched area represents a short-circuit current due to white bias light (for example, AM1.5G) having a wide wavelength range. A region obtained by combining a dense hatching region and a rough hatching region represents a short-circuit current caused by light obtained by superimposing white bias light and monochromatic light.

  The short-circuit current due to the white bias light is a value obtained from the convolution integral of the spectral sensitivity of the solar cell and the irradiance of the irradiated light source, and has no wavelength dependency. On the other hand, the short circuit current due to monochromatic light is different at wavelengths of 300 to 1100 nm. In the calculation of DSR, the calculation is performed based on the short-circuit current due to the measured white bias for each white bias light, so that the short-circuit current due to the white bias light that is the base changes greatly due to the monochromatic light. This causes a measurement error in absolute spectral sensitivity.

The graph shown in Figure 1, white bias light of 1000W / ^{m 2,} shows the case of a monochromatic light of 1W / ^{m 2.} The area with rough hatching indicated by ib — 1000 W represents a short-circuit current due to white bias light of 1000 W / m ² . A densely hatched area indicated by ib_s (λ) represents a short-circuit current due to monochromatic light of 1 W / m ² .

White bias light of 1000W / ^{m 2,} in the case of the monochromatic light of 1W / ^{m 2,} the ratio of irradiance 1000: 1, and the specific is large, relative to the short-circuit current due to the white bias light, short circuit due to monochromatic light Current fluctuation is relatively small. For this reason, the measurement error amount of the absolute spectral sensitivity is small.

According to actual measurement by the present inventor, the short-circuit current due to white bias light of 1000 W / m ² was 8 mA, and the short-circuit current due to monochromatic light (wavelength 546 nm) of 1 W / m ² was 86 μA. Therefore, the ratio of the short-circuit current due to the monochromatic light to the short-circuit current due to the white bias light was about 1% (= (86 μA / 8 mA) × 100). This indicates that the fluctuation of the short-circuit current due to the monochromatic light is relatively small with respect to the short-circuit current due to the white bias light.

Non-linear solar cells are solar cells having different spectral sensitivities depending on irradiance. When measuring the absolute spectral sensitivity of a non-linear solar cell by the DSR method, it is necessary to measure the differential spectral sensitivity at the irradiance of white bias light in which the short-circuit current changes greatly. For example, some dye-sensitized solar cells have large nonlinearity near 10 W / m ² . When measuring the absolute spectral sensitivity of such a solar cell, it is important to measure the differential spectral sensitivity in white bias light of 10 W / m ² .

The graph shown in FIG. 2, white bias light of 10 W / ^{m 2,} shows the case of a monochromatic light of 1W / ^{m 2.} The area | region where hatching shown by ib_10W is rough represents the short circuit current by the white bias light of 10 W / m < ² >. A densely hatched area indicated by ib_s (λ) represents a short-circuit current due to monochromatic light of 1 W / m ² .

White bias light of 10 W / m ^2, in the case of monochromatic light of 1W / m ^2, the ratio of the irradiance 10: 1, the ratio of the irradiance is small, relative to the short-circuit current due to the white bias light, monochromatic The fluctuation of the short circuit current due to light is relatively large. In addition, due to the spectral sensitivity characteristics of the solar cell to be measured, the short-circuit current due to the monochromatic light varies greatly depending on the wavelength of the monochromatic light. These cause measurement errors in absolute spectral sensitivity.

According to actual measurement by the present inventor, the short-circuit current by white bias light of 10 W / m ² was 80 μA, and the short-circuit current by monochromatic light of 1 W / m ² (wavelength 546 nm) was 86 μA. Therefore, the ratio of the short-circuit current due to the monochromatic light to the short-circuit current due to the white bias light was about 108% (= (86 μA / 80 μA) × 100). This indicates that the fluctuation of the short-circuit current due to the monochromatic light is relatively large with respect to the short-circuit current due to the white bias light.

  As described above, in the DSR method, when measuring each differential spectral sensitivity for each irradiance by sequentially changing the irradiance of the white bias light, if the irradiance of the monochromatic light is the same, the absolute spectral It causes a measurement error of sensitivity.

  Therefore, by setting the ratio of the irradiance of the white bias light and the irradiance of the monochromatic light in advance, when the irradiance of the white bias light is large, the irradiance of the monochromatic light is increased and the irradiance of the white bias light is increased. When it is small, the irradiance of monochromatic light is reduced.

For example, the ratio between the irradiance of white bias light and the irradiance of monochromatic light is set to 1000: 1. When the white bias light is 1000 W / m ² , the monochromatic light is 1 W / m ² . In this case, since the graph shown in FIG. 1 is obtained, the fluctuation of the short-circuit current due to the monochromatic light is relatively small with respect to the short-circuit current due to the white bias light.

When the white bias light is 10 W / m ² , the monochromatic light is 0.01 W / m ² . In this case, the graph shown in FIG. 3 is obtained instead of the graph shown in FIG. The area | region where hatching shown by ib_10W is rough represents the short circuit current by the white bias light of 10 W / m < ² >. A dense hatched area indicated by ib_s (λ) represents a short-circuit current by monochromatic light of 0.01 W / m ² . The short-circuit current due to the monochromatic light is relatively small with respect to the short-circuit current due to the white bias light.

According to actual measurement by the present inventor, the short-circuit current with white bias light of 10 W / m ² was 80 μA, and the short-circuit current with monochromatic light of 0.01 W / m ² (wavelength 546 nm) was 860 nA. Therefore, the ratio of the short-circuit current due to the monochromatic light to the short-circuit current due to the white bias light was about 1% (= (860 nA / 80 μA) × 100). This indicates that the fluctuation of the short-circuit current due to the monochromatic light is relatively small with respect to the short-circuit current due to the white bias light.

  Next, the configuration of the spectral sensitivity measuring apparatus 1 according to this embodiment will be described. FIG. 4 is a block diagram showing the configuration. The spectral sensitivity measurement apparatus 1 includes a first light source unit 2, a second light source unit 3, an irradiation unit 4, a current measurement unit 5, a control unit 6, an input unit 7, and an output unit 8.

  The first light source unit 2 adjusts the amount of white bias light and emits white bias light. White bias light is an example of bias light. The first light source unit 2 includes a first light emitting unit 20, a plane mirror 21, a shutter 22, an optical filter 23, a diaphragm 24 (specific example of the first diaphragm), and an ND (Neutral Density) filter 25 (first ND filter). Specific example).

  The first light emitting unit 20 emits white bias light. The white bias light is light for causing a certain amount of short-circuit current to flow through the solar cell of the measurement target W. The first light emitting unit 20 is, for example, a halogen lamp or a xenon lamp.

  A plane mirror 21 is disposed in the optical path of the white bias light emitted from the first light emitting unit 20. The plane mirror 21 reflects the white bias light emitted from the first light emitting unit 20.

  A shutter 22, an optical filter 23, an aperture 24, and an ND filter 25 are sequentially arranged on the optical path of the white bias light reflected 90 degrees by the plane mirror 21.

  When the shutter 22 is open, white bias light is emitted from the first light source unit 2, and when the shutter 22 is closed, light is shielded and no white bias light is emitted from the first light source unit 2. Since it takes time for the first light emitting unit 20 to emit stable white bias light, the first light emitting unit 20 is in an ON state and emits white bias light while the spectral sensitivity measuring apparatus 1 is in use. ing. When the white bias light is used, the shutter 22 is opened, and when the white bias light is not used, the shutter 22 is closed.

  In the international standard, AM1.5G (Air Mass 1.5G) is defined as reference sunlight for solar cell evaluation. The optical filter 23 converts the white bias light emitted from the first light emitting unit 20 into white bias light (pseudo-sunlight) having a spectral spectrum that approximates the spectral spectrum of the reference sunlight defined by AM1.5G. To do.

  The amount of white bias light converted to pseudo sunlight by the optical filter 23 is adjusted by the diaphragm 24 and the ND filter 25. The diaphragm 24 is, for example, a luminous diaphragm that varies the aperture area. As the diaphragm 24, a plate member having a plurality of through holes with different aperture ratios may be used instead of the iris diaphragm. Specifically, the plate member is a punching metal in which a plurality of through holes having different opening ratios are two-dimensionally formed. The diaphragm 24 and the ND filter 25 function as a first adjustment unit 26 that adjusts the amount of white bias light emitted by the first light emitting unit 20. The diaphragm 24 and the ND filter 25 can be set to obtain a predetermined light amount by attenuating the amount of white bias light. Either the diaphragm 24 or the ND filter 25 may not be disposed, and either one may be disposed as the first adjusting unit 26.

  The white bias light that has passed through the diaphragm 24 and the ND filter 25 is emitted to the outside from the first light source unit 2, and this white bias light is incident on the irradiation unit 4.

  The second light source unit 3 adjusts the amount of monochromatic light and emits monochromatic light. The second light source unit 3 includes a second light emitting unit 30, a slit 31, a diaphragm 32 (specific example of the second diaphragm), a diffraction grating 33, a shutter 34, and an ND filter 35 (specific example of the second ND filter). And a chopper 36.

  The second light emitting unit 30 emits light in a predetermined wavelength band including the wavelength of monochromatic light selected by the diffraction grating 33. The second light emitting unit 30 is, for example, a white lamp such as a xenon lamp. In the second light source unit 3, the light from the first light-emitting unit 20 and the light from the second light-emitting unit 30 intersect, but this is the reason for drawing and actually intersects. Not done.

  A slit 31, a stop 32, and a diffraction grating 33 are disposed in the optical path of the light emitted from the second light emitting unit 30. The second light source unit 3 includes a monochromator 38 including a slit 31 and a diffraction grating 33 as components. The monochromator 38 is a specific example of the monochromatic light generation unit, and generates monochromatic light using the light emitted by the second light emitting unit 30.

  The monochromator 38 is a device that emits the light emitted from the second light emitting unit 30 by making it monochromatic light at a predetermined wavelength according to an instruction from the control unit 6. The monochromator 38 is, for example, a spectroscope that diffracts light of a predetermined wavelength band emitted from the second light emitting unit 30 with the diffraction grating 33 and extracts only a narrow range of wavelengths.

  The monochromator 38 includes, for example, an entrance slit (slit 31), a reflective diffraction grating 33, and an exit slit (not shown), and diffracts an incident light beam incident through the entrance slit by the reflective diffraction grating 33. In this apparatus, only a predetermined wavelength is extracted from the diffracted light of the incident light beam diffracted by the diffraction grating 33 by the exit slit. With such a configuration, the monochromator 38 can extract only the wavelength in a desired range by rotating the diffraction grating 33 and the like to select the wavelength of light reaching the slit position (single-color light conversion).

  The monochromator 38 is controlled by the controller 6 so as to extract a desired range of wavelengths.

  The diaphragm 32 is, for example, a chromatic diaphragm, and adjusts the amount of light that has passed through the slit 31. The diaphragm 32 functions as a second adjustment unit 37 described later. Note that a plate member having a plurality of through holes with different aperture ratios may be used as the diaphragm 32 instead of the iris diaphragm. Specifically, the plate member is a punching metal in which a plurality of through holes having different opening ratios are two-dimensionally formed.

  A shutter 34, an ND filter 35, and a chopper 36 are arranged in this order on the optical path of monochromatic light emitted from the monochromator 38.

  When the shutter 34 is opened, the monochromatic light is emitted from the second light source unit 3, and when the shutter 34 is closed, the monochromatic light is not emitted from the second light source unit 3. Since it takes time for the second light emitting unit 30 to emit stable light, the second light emitting unit 30 is in an ON state and emits light during use of the spectral sensitivity measuring apparatus 1. When using monochromatic light, the shutter 34 is opened, and when not using monochromatic light, the shutter 34 is closed.

  The ND filter 35 and the diaphragm 32 function as a second adjustment unit 37 that adjusts the amount of monochromatic light generated by the monochromator 38 (monochromatic light generation unit). The ND filter 35 and the diaphragm 32 can be set to a predetermined light amount by attenuating the light amount of monochromatic light. Either one of the ND filter 35 and the diaphragm 32 may be arranged instead of the ND filter 35 and the diaphragm 32 to form the second adjustment unit 37.

  The monochromatic light whose light amount is adjusted by the ND filter 35 enters the chopper 36. The chopper 36 alternately turns on and off by periodically chopping the incident monochromatic light. Thereby, monochromatic light whose light quantity changes in a pulse shape is obtained. The monochromatic light is emitted to the outside from the second light source unit 3 and enters the irradiation unit 4.

  The irradiation unit 4 generates combined light, which is light obtained by superimposing the white bias light emitted from the first light source unit 2 and the monochromatic light emitted from the second light source unit 3, and is placed on the stage 9. The measurement object W is irradiated. The measurement target W is a reference detector or a solar battery.

  When measuring the absolute spectral sensitivity of a solar cell, the measuring object W is a solar cell. Prior to this measurement, the spectral sensitivity measuring apparatus 1 is calibrated so that the white bias light and the monochromatic light have desired light quantities as will be described later. During this calibration operation, the measurement target W is a reference detector.

The reference detector is a device in which, for example, in STC (1000 W / m ² , 25 degrees, AM1.5G), the short-circuit current and the spectral sensitivity output from the reference detector are specified in advance. The reference detector is, for example, a reference solar cell or a Si photodiode.

  The irradiation unit 4 includes a half mirror 40, a light projecting lens 41, and a mask 42. The white bias light emitted from the first light source unit 2 and the monochromatic light emitted from the second light source unit 3 are overlapped by the half mirror 40, and light (combined light) obtained by superimposing the white bias light and the monochromatic light. Is generated. The combined light is collected by the light projecting lens 41 and irradiated onto the measurement object W through the mask 42.

  The synthesized light has a uniform brightness at the center of the cross section, but the brightness is not uniform at the periphery due to the shading characteristics of the lens. For this purpose, only the central part of the combined light is irradiated onto the measuring object W by the mask 42.

  The current measuring unit 5 measures the short-circuit current of the measurement target W. The current measuring unit 5 includes a lock-in amplifier 50. The lock-in amplifier 50 is in a state in which the irradiation unit 4 irradiates the measurement target W with the combined light (in other words, for each of a plurality of combinations created by the combination creation unit 62, the first control is performed by the emission control unit 63). Of the short-circuit current measured by the current measuring unit 5 in a state in which the bias light emitted from the light source unit 2 and the monochromatic light emitted from the second light source unit 3 are superimposed on each other and irradiated onto the measuring object W) Therefore, this circuit has a function of detecting and amplifying only a short-circuit current due to monochromatic light. Alternatively, without using a lock-in amplifier, the AC light component may be extracted by measuring the short-circuit current from the combined light of the steady light and the AC light.

  The control unit 6 controls the spectral sensitivity measuring device 1. FIG. 5 is an explanatory diagram illustrating functional blocks of the control unit 6. The control unit 6 is realized by a CPU, a RAM, a ROM, and the like, and functions as a light amount ratio storage unit 60, a bias light amount storage unit 61, a combination creation unit 62, an emission control unit 63, a difference spectral sensitivity calculation unit 64, an absolute spectrum. A sensitivity calculation unit 65, a first short-circuit current calculation unit 66, a first set value calculation unit 67, a first set value storage unit 68, a second short-circuit current calculation unit 69, a second set value calculation unit 70, A second set value storage unit 71 and a storage control unit 72 are provided. Details of these blocks will be described later.

  With reference to FIG. 4, the input unit 7 is a device for inputting a command (command), data, and the like from the outside to the spectral sensitivity measuring device 1, and is, for example, a touch panel or a keyboard.

  The output unit 8 is a device for outputting the command and data input from the input unit 7 and the calculation result of the control unit 6, for example, a display device such as an LCD (liquid crystal display) or an organic EL display, A printing apparatus such as a printer.

  The operation of the spectral sensitivity measuring apparatus 1 according to this embodiment will be described. 6 and 7 are flowcharts for explaining the operation. The spectral sensitivity measuring apparatus 1 performs various settings as a premise for measuring the absolute spectral sensitivity of the solar cell. FIG. 8 is a table summarizing various settings. This table will be described together with the operation of the spectral sensitivity measuring apparatus 1.

  4 to 6, the operator operates the input unit 7 to calibrate the absolute value of the light amount of the apparatus in order to measure the absolute spectral sensitivity of the solar cell. In order to perform the absolute value calibration, the emission control unit 63 performs control to close the shutter 22 of the first light source unit 2 and the shutter 34 of the second light source unit 3, and the first light emitting unit 20 and the first light emitting unit 20. Control is performed to turn on the second light emitting unit 30 (step S1). Since it takes time to stabilize the white bias light emitted from the first light emitting unit 20 and the light emitted from the second light emitting unit 30, the first light emitting unit 20 and the second light emitting unit 30 are turned on in advance. To do.

  The operator operates the input unit 7 to input a value K indicating the ratio between the first light amount that is the amount of white bias light and the second light amount that is the amount of monochromatic light (step S2). For example, when the first light quantity: the second light quantity = 1000: 1, 1000 is input as the value K. The storage control unit 72 stores the input value K in the light amount ratio storage unit 60. The operator can input a desired value to the spectral sensitivity measuring apparatus 1 as the value K indicating the ratio.

  Note that the value K may be a default value. That is, the value K is set in the light amount ratio storage unit 60 by default. According to this, the operation (step S2) of inputting the value K indicating the ratio to the spectral sensitivity measuring apparatus 1 can be omitted. This is effective when the value K indicating the ratio is unknown.

  The operator operates the input unit 7 to input a plurality of different first light amounts (step S3). Eb_i indicates the first light quantity. i represents any number from 1 to n. n is an integer greater than 1. For example, n is 10 (that is, 10 types of first light amounts), but for simplification of description, n is 3 (that is, 3 first light amounts) as an example.

  It is assumed that a first light amount (for example, 1000) indicated by Eb_1, a first light amount (for example, 500) indicated by Eb_2, and a first light amount (for example, 100) indicated by Eb_3 are input. The storage control unit 72 causes the bias light amount storage unit 61 to store a plurality of input first light amounts different from each other. In FIG. 8, the numbers (1000, 500, 100) shown in the first light quantity column correspond to the input first light quantity.

  The combination creating unit 62 represents a plurality of second light amounts corresponding to the plurality of first light amounts stored in the bias light amount storage unit 61, and a value K indicating a ratio stored in the light amount ratio storage unit 60. And a plurality of combinations of the first light quantity and the second light quantity corresponding to the first light quantity are created (step S4). Em_i indicates the second light quantity.

  The value K is assumed to be 1000. When the first light quantity indicated by Eb_1 is 1000, the second light quantity indicated by Em_1 is 1, and these are one combination. When the first light quantity indicated by Eb_2 is 500, the second light quantity indicated by Em_2 is 0.5, and these are one combination. When the first light quantity indicated by Eb_3 is 100, the second light quantity indicated by Em_3 is 0.1, and these are one combination. The number of combinations is the same as the number of first light amounts and the number of second light amounts.

  In FIG. 8, the numbers (1, 0.5, 0.1) shown in the second light quantity column correspond to the second light quantity calculated using the value K.

  Next, the absolute value of the amount of white bias light emitted from the first light source is obtained (steps S5 to S8). More specifically, the operator places the reference detector (measurement target W) on the stage 9. The control unit 6 inputs a command for obtaining the absolute value of the amount of white bias light. Thus, the emission control unit 63 performs control to open the shutter 22 of the first light source unit 2 and close the shutter 34 of the second light source unit 3. By this control, the white bias light emitted from the first light source unit 2 is irradiated to the reference detector of the measurement target W by the irradiation unit 4. In this state, the current measurement unit 5 measures the short-circuit current Ib_stc output from the reference detector (step S5).

  The emission control unit 63 determines whether or not the short circuit current Ib_stc matches the short circuit current Istc (step S6). The short circuit current Istc is a short circuit current output from the reference detector in the STC and is specified in advance.

  When the emission control unit 63 determines that the short-circuit current Ib_stc does not match the short-circuit current Istc (No in step S6), the first adjustment unit 26 (that is, the diaphragm 24 and the ND filter 25 of the first light source unit 2). To adjust the amount of white bias light emitted from the first light source unit 2 (step S7). Then, the process returns to step S5.

  When the emission control unit 63 determines that the short-circuit current Ib_stc matches the short-circuit current Istc (Yes in step S6), the absolute value of the amount of white bias light is determined. The emission control unit 63 stores the values set in the first adjustment unit 26 at this time (that is, the values set in the diaphragm 24 and the ND filter 25 of the first light source unit 2) (step S8). ).

  Referring to FIG. 7, a first setting value that is a setting value for changing the light amount of the white bias light to the plurality of first light amounts described in step S3 is obtained (step S9). FIG. 9 is a flowchart for explaining this.

  4, 5, and 9, the reference detector (measurement target W) is continuously placed on stage 9. The first short-circuit current calculation unit 66 uses a plurality of first light amounts stored in the bias light amount storage unit 61 and a first predetermined formula, and a plurality of first short circuit current calculation units 66 correspond to each of the plurality of first light amounts. The first short-circuit current is calculated. The first short-circuit current is a short-circuit current output from the reference detector in a state in which the first light amount of bias light described in step S3 is applied to the reference detector.

  The first short circuit current calculation unit 66 stores a first predetermined formula shown below.

Ib_i = Istc / 1000 × Eb_i
Ib_i is a first short-circuit current. Istc is a short-circuit current output from the reference detector in the STC. Eb_i is the first irradiance. 1000 is a value for converting to current per unit irradiance since Istc is defined by irradiance 1000 [W / m ² ].

  The first short circuit current calculation unit 66 sets i = 1 (step T1). The first short-circuit current calculator 66 outputs the first short-circuit current output from the reference detector when the white light of the first light amount indicated by Eb_1 among the plurality of first light amounts is irradiated to the reference detector. The short circuit current Ib_1 is calculated (step T2).

  The emission control unit 63 performs control for opening the shutter 22 of the first light source unit 2 and closing the shutter 34 of the second light source unit 3. Thereby, the white bias light emitted from the first light source unit 2 is irradiated to the reference detector by the irradiation unit 4. In this state, the current measuring unit 5 measures the short-circuit current Ib output from the reference detector (step T3).

  The first set value calculator 67 calculates the short-circuit current measured by the current measuring unit 5 in a state where the white bias light is irradiated on the reference detector, and the plurality of first set values calculated by the first short-circuit current calculator 66. A plurality of first set values corresponding to each of the plurality of first short-circuit currents are calculated in comparison with each of the one short-circuit currents. The first set value is a value set in the first adjustment unit 26 so that the reference detector outputs the first short-circuit current. Thereby, the setting value for emitting the bias light can be determined based on the current value from the reference detector instead of measuring the irradiance.

  The first set value calculation unit 67 will be described in detail. The first set value calculation unit 67 determines whether or not the short-circuit current Ib from the reference detector measured by the current measurement unit 5 matches the first short-circuit current Ib_1 (step T4).

  When the first set value calculation unit 67 determines that the short circuit current Ib does not match the first short circuit current Ib_1 (No in Step T4), the emission control unit 63 controls the first adjustment unit 26. The amount of white bias light emitted from the first light source unit 2 is adjusted (step T5). Then, the process returns to step T3.

  When the first set value calculation unit 67 determines that the short-circuit current Ib matches the first short-circuit current Ib_1 (Yes in step T4), the value set in the first adjustment unit 26 at this point (that is, , Values set in the diaphragm 24 and the ND filter 25 of the first light source unit 2) are stored as the first set values in the first set value storage unit 68 (step T6).

  The first short-circuit current calculator 66 determines whether i = n (step T7). In this embodiment, n = 3. Since i = 1, the first short circuit current calculation unit 66 sets i = 2 (step T8). Then, the process returns to step T2.

  When the first short-circuit current calculation unit 66 determines that i = n (Yes in step T7), the process for obtaining the first set value ends. The first setting value storage unit 68 stores a plurality (n) of first setting values calculated by the first setting value calculation unit 67. In FIG. 8, the symbol shown in the column of the first set value indicates the first set value. The above is the description of step S9 in FIG.

  Referring to FIG. 7, a second set value, which is a set value for changing the light amount of the monochromatic light to the plurality of second light amounts described in step S4, is obtained (step S10). The second set value is a value set in the second adjustment unit 37. The reason why the second setting value is necessary for each wavelength will be described.

  FIG. 10 is a graph showing the relationship between wavelength and irradiance for a xenon lamp used as the second light emitting unit 30. The horizontal axis represents the wavelength of light emitted by the xenon lamp. The vertical axis represents the irradiance of light emitted by the xenon lamp.

  It can be seen that the light emitted by the xenon lamp has different irradiance depending on the wavelength. The second set value is determined for each wavelength of light emitted by the second light emitting unit 30, and the monochromatic light emitted from the second light source unit 3 has the same irradiance (second) even if the wavelength is different. Is a value set in the second adjustment unit 37 so as to be equal to (amount of light). By setting the value set in the second adjustment unit 37 to the second set value, the monochromatic light emitted from the second light source unit 3 may have different wavelengths as shown by the dotted line in FIG. The same irradiance.

  FIG. 11 is a flowchart for explaining the step of obtaining the second set value. Referring to FIGS. 4, 5, and 11, the reference detector (measurement target W) is continuously placed on stage 9. The second short-circuit current calculation unit 69 uses the second light amount calculated by the combination creation unit 62, the second predetermined formula, and the spectral sensitivity of the reference detector, and each of two or more monochromatic lights having different wavelengths. Two or more second short-circuit currents corresponding to are calculated. The second short-circuit current is a short-circuit current that is output from the reference detector in a state in which the reference light is irradiated with the monochromatic light having the second light quantity described in step S4. The second short circuit current calculation unit 69 calculates two or more second short circuit currents for each of the plurality of second light quantities described in step S4.

  The second short circuit current calculation unit 69 stores a second predetermined formula shown below.

Im_i_λj = S (λj) × Em_i
Im_i_λj is a second short-circuit current. The second short-circuit current differs depending on the wavelength of the monochromatic light even if the second light amount is the same. S (λj) is the spectral sensitivity of the reference detector and varies depending on the wavelength of the monochromatic light.

  j represents any number from 1 to m. m is an integer greater than 1. For example, when the wavelength range of 300 to 1100 nm is divided in units of 10 nm, m is 80. For simplification of description, the description will be made by taking m as an example. M is 4 when the wavelength range of 300 to 1100 nm is divided into units of 200 nm. For example, when 300 nm ≦ λ1 <500 nm, 400 nm is a representative value of λ1, 500 nm ≦ λ2 <700 nm, 600 nm is a representative value of λ2, 700 nm ≦ λ3 <900 nm, 800 nm is a representative value of λ3, and 900 nm ≦ λ4 ≦ 1100 nm, 1000 nm is a representative value of λ4. In FIG. 8, 400 nm, 600 nm, 800 nm, and 1000 nm correspond to the case of m4.

  When i = 1 and j = 1, the second short-circuit current calculation unit 69 outputs the second short-circuit current output from the reference detector when the reference detector is irradiated with the monochromatic light having the second light quantity indicated by Em_1. The short circuit current Im_1_λ1 is calculated (step U2).

  The emission control unit 63 performs control to close the shutter 22 of the first light source unit 2 and open the shutter 34 of the second light source unit 3. As a result, the monochromatic light having the wavelength λ 1 emitted from the second light source unit 3 is irradiated to the reference detector by the irradiation unit 4. In this state, the current measuring unit 5 measures the short-circuit current Imes_1_1 output from the reference detector (step U3).

  The second set value calculation unit 70 calculates the short-circuit current measured by the current measurement unit 5 in a state where the monochromatic light is applied to the reference detector, and the two or more second set-value calculation units 69 calculate the second short-circuit current calculation unit 69. Compared with each of the two short-circuit currents, two or more second set values corresponding to each of the two or more second short-circuit currents are calculated. The second set value is a value set in the second adjustment unit 37 so that the reference detector outputs the second short-circuit current. Thereby, the setting value for emitting monochromatic light can be determined based on the current value from the reference detector, instead of measuring the irradiance. The second set value calculation unit 70 calculates two or more second set values for each of the plurality of second light amounts.

  “Plural” and “2 or more” are integers of 2 or more. Let “plurality” be n, and “two or more” be m. n and m may be the same or different. The second short circuit current calculation unit 69 calculates n × m second short circuit currents, and the second set value calculation unit 70 calculates n × m second set values.

  The second set value calculation unit 70 will be described in detail. The second set value calculation unit 70 determines whether or not the short-circuit current Imes_1_1 from the reference detector measured by the current measurement unit 5 matches the second short-circuit current Im_1_λ1 (step U4).

  When the second set value calculation unit 70 determines that the short circuit current Imes_1_1 does not match the second short circuit current Im_1_λ1 (No in step U4), the emission control unit 63 controls the second adjustment unit 37. Then, the amount of monochromatic light emitted from the second light source unit 3 is adjusted (step U5). Then, the process returns to step U3.

  When the second set value calculation unit 70 determines that the short-circuit current Imes_1_1 matches the second short-circuit current Im_1_λ1 (Yes in step U4), the value set in the second adjustment unit 37 at this time (that is, the value) , Values set in the diaphragm 32 and the ND filter 35 of the second light source unit 3) are stored in the second set value storage unit 71 as second set values (step U6).

  The second short-circuit current calculating unit 69 determines whether j = m (step U7). In this embodiment, m = 4. Since j = 1, the second short circuit current calculation unit 69 determines that j = m is not satisfied (No in step U7). The second short circuit current calculation unit 69 sets j = 2 (step U8). Then, the process returns to step U2.

  When the second short circuit current calculation unit 69 determines that j = m (Yes in step U7), the second short circuit current calculation unit 69 determines whether i = n (step U9). In this embodiment, n = 3. When the second short circuit current calculation unit 69 determines that i = n is not satisfied (No in step U9), the second short circuit current calculation unit 69 sets i = i + 1 (step U10). Then, the process returns to step U2.

  When the second short-circuit current calculation unit 69 determines that i = n (Yes in step U9), the process for obtaining the second set value ends. The second set value storage unit 71 stores two or more (m) second set values for each of a plurality (n) of second light quantities calculated by the second set value calculating unit 70. Are stored as a plurality (n × m) of second set values. In FIG. 8, the symbol shown in the column of the second set value indicates the second set value. The above is the description of step S10 in FIG.

  Steps S1 to S10 are various settings for measuring the absolute spectral sensitivity of the solar cell. Next, calculation of the absolute spectral sensitivity of the solar cell will be described. With reference to FIGS. 4, 5, and 7, the operator places the solar cell of the measuring object W on the stage 9. The operator operates the input unit 7 to input a command for measuring the absolute spectral sensitivity. As a result, the emission control unit 63 reads out the first set value from which the first light amount indicated by Eb_1 is obtained among the plurality of first set values stored in the first set value storage unit 68. This is set in the first adjustment unit 26 (step S11). Then, the emission control unit 63 obtains the second light amount indicated by Em_1 at each of the wavelengths λ1 to λm among the plurality of second setting values stored in the second setting value storage unit 71. The second set values are read out and set in order in the second adjustment unit 37 (step S12).

  The emission control unit 63 performs control to open the shutter 22 of the first light source unit 2 and the shutter 34 of the second light source unit 3. Thereby, the white bias light emitted from the first light source unit 2 and the monochromatic light emitted from the second light source unit 3 are synthesized by the irradiation unit 4, and this synthesized light is combined with the solar cell (measurement target W). Irradiated. In this state, the current measurement unit 5 measures the short-circuit current output from the solar cell (measurement step). The difference spectral sensitivity calculation unit 64 calculates the difference spectral sensitivity when the white bias light is the first light amount indicated by Eb_1 using the short-circuit current and the short-circuit current due to the monochromatic light (step S13).

  Note that the lock-in amplifier 50 is used to measure the short-circuit current with monochromatic light. The lock-in amplifier 50 detects and amplifies the short-circuit current due to the monochromatic light from the short-circuit current measured in the measurement step. The difference spectral sensitivity calculation unit 64 uses a short-circuit current due to monochromatic light detected by the lock-in amplifier 50 in calculating the difference spectral sensitivity. The lock-in amplifier 50 can extract the monochromatic light of the AC component from the short circuit current (stationary light) due to the white bias light and the short circuit current (AC light) obtained by chopping the monochromatic light.

  The following method may be used for measuring the short-circuit current with monochromatic light. The short-circuit current measured by the current measuring unit 5 without white bias light being emitted from the first light source unit 2 and monochromatic light being emitted from the second light source unit 3 under the control of the emission control unit 63 Is a short-circuit current by monochromatic light. The difference spectral sensitivity calculation unit 64 uses the short-circuit current in calculating the difference spectral sensitivity.

  The difference spectral sensitivity calculation unit 64 determines whether i = n (step S14). In this embodiment, n = 3. Since i = 1, the differential spectral sensitivity calculation unit 64 sets i = 2 (step S15). Then, the process returns to step S11.

  The operations of the emission controller 63 and the difference spectral sensitivity calculator 64 in the processes of No and Step S15 in Step S11, Step S12, Step S13, and Step S14 are summarized as follows. The emission control unit 63 causes the first light source unit 2 to emit white bias light of the first light amount for each of the plurality of combinations created by the combination creation unit 62 (step S4 in FIG. 6), and the second The light source unit 3 emits monochromatic light having the second light quantity. Specifically, the emission control unit 63 sets each of the plurality of first setting values stored in the first setting value storage unit 68 in the first adjustment unit 26, so that the first light source unit 2 The white bias light is emitted, and the emission control unit 63 sets each of the plurality of second setting values stored in the second setting value storage unit 71 in the second adjustment unit 37, and Monochromatic light is emitted to the two light source units 3. The difference spectral sensitivity calculation unit 64 uses the short-circuit current measured by the current measurement unit 5 in a state where the irradiation unit 4 irradiates the solar cell with the synthesized light for each of the plurality of combinations created by the combination creation unit 62. A plurality of differential spectral sensitivities are obtained by calculating differential spectral sensitivities.

  When the difference spectral sensitivity calculation unit 64 determines that i = n (Yes in step S14), the absolute spectral sensitivity calculation unit 65 sets the plurality (n) of difference spectral sensitivities obtained by the difference spectral sensitivity calculation unit 64. In step S16, the absolute spectral sensitivity of the solar cell is calculated.

  The main effects of this embodiment will be described. The absolute spectral sensitivity measurement of a solar cell using the DSR method includes a step of measuring a plurality of differential spectral sensitivities by measuring each differential spectral sensitivity with respect to each light amount by sequentially changing the light amount of white bias light (step S11). Step S12, Step S13, Step S14 No, Step S15). In the spectral sensitivity measuring apparatus 1 according to the present embodiment, the ratio of the amount of white bias light to the amount of monochromatic light is set in advance (step S2 in FIG. 6), whereby the amount of white bias light is large in the above process. When the amount of monochromatic light is increased to improve the SN during monochromatic light measurement, the amount of monochromatic light is decreased when the amount of white bias light is small. Thereby, for each white bias light, the influence of the short circuit current due to the monochromatic light can be made relatively small with respect to the short circuit current due to the white bias light, and the influence of the short circuit current fluctuation in each irradiance can be eliminated. In the measurement of the absolute spectral sensitivity of a solar cell using the method, it is possible to obtain the differential spectral sensitivity with high accuracy under an arbitrary amount of bias light.

  In the present embodiment, there are a first modification and a second modification. A first modification will be described. In step S4 of FIG. 6, the combination creating unit 62 (FIG. 5) uses the second light quantity that is equal to or lower than a predetermined lower limit value among the plurality of second light quantities calculated using the value K indicating the ratio. Let the lower limit value be the second light quantity.

  If the second light amount, which is the light amount of monochromatic light, is less than a certain value, the influence of the short-circuit current due to the monochromatic light on the short-circuit current due to the white bias light is negligible, and thus does not cause a large measurement error. On the other hand, when the light quantity ratio (value indicating the ratio) is the same regardless of the magnitude of the light quantity of the monochromatic light, if the white bias light is small, the SN ratio of the short-circuit current measurement using the monochromatic light is deteriorated. Accordingly, since the difference spectral sensitivity measurement accuracy may be deteriorated, a lower limit is provided for the amount of monochromatic light.

  A second modification will be described. In step S2 of FIG. 6, the light amount ratio storage unit 60 (FIG. 5) stores a value K indicating a plurality of ratios assigned to each of the plurality of first light amounts. The combination creating unit 62 calculates a plurality of second light amounts corresponding to each of the plurality of first light amounts, using a value K indicating a ratio assigned to each of the plurality of first light amounts.

  According to the second modification, the ratio can be changed according to each of the plurality of first light amounts, so that the plurality of second light amounts can be set to optimum values.

  The ratios can be different from each other according to the plurality of first light quantities. For example, a plurality of first light amounts are set as a light amount A, a light amount B, a light amount C, a light amount D, and a light amount E in ascending order. The ratio assigned to the light quantity A is 200: 1, the ratio assigned to the light quantity B is 400: 1, the ratio assigned to the light quantity C is 600: 1, the ratio assigned to the light quantity D is 800: 1, and the ratio assigned to the light quantity E is 1000: 1. To do.

  Further, the plurality of first light amounts may be divided into several groups, and the ratios may be different from each other depending on the group. For example, the ratio assigned to the group of the light quantity A, the light quantity B, and the light quantity C is set to 500: 1, and the ratio assigned to the group of the light quantity D and the light quantity E is set to 1000: 1.

DESCRIPTION OF SYMBOLS 1 Spectral sensitivity measuring apparatus 2 1st light source part 3 2nd light source part 4 Irradiation part 5 Current measurement part 20 1st light emission part 26 1st adjustment part 30 2nd light emission part 37 2nd adjustment part 38 Monochrome Meter (specific example of monochromatic light generator)
DESCRIPTION OF SYMBOLS 50 Lock-in amplifier 60 Light quantity ratio memory | storage part 61 Bias light quantity memory | storage part 62 Combination production part 63 Output control part 64 Difference spectral sensitivity calculation part 65 Absolute spectral sensitivity calculation part 66 1st short circuit current calculation part 67 1st setting value calculation part 68 First setting value storage unit 69 Second short-circuit current calculation unit 70 Second setting value calculation unit 71 Second setting value storage unit 72 Storage control unit W Measurement object Eb_i First light amount Em_i Second light amount Ib_i First short-circuit current Im_i_λj Second short-circuit current

Claims (11)

A first light source unit that adjusts the amount of bias light and emits the bias light;
A second light source unit that adjusts the amount of monochromatic light and emits the monochromatic light;
A current measuring unit for measuring the short-circuit current of the solar cell to be measured;
A light amount ratio storage unit that stores a value indicating a predetermined ratio between a first light amount that is the light amount of the bias light and a second light amount that is the light amount of the monochromatic light;
A bias light quantity storage unit that stores a plurality of different first light quantities;
The plurality of second light amounts corresponding to each of the plurality of first light amounts stored in the bias light amount storage unit are calculated using a value indicating the ratio stored in the light amount ratio storage unit. A combination creating unit that creates a plurality of combinations of the first light quantity and the second light quantity corresponding to the first light quantity;
For each of the plurality of combinations created by the combination creation unit, the first light source unit emits the first light amount of the bias light, and the second light source unit emits the second light amount of the second light amount. An emission control unit for emitting monochromatic light;
For each of the plurality of combinations created by the combination creation unit, the bias light emitted from the first light source unit and the monochromatic light emitted from the second light source unit under the control of the emission control unit And calculating the difference spectral sensitivity using the short-circuit current measured by the current measurement unit in a state where the solar cell is irradiated with ,
A spectral sensitivity measurement apparatus comprising: an absolute spectral sensitivity calculation unit that calculates an absolute spectral sensitivity of the solar cell using the plurality of differential spectral sensitivities obtained by the differential spectral sensitivity calculation unit.   The combination creation unit sets the lower limit value for the second light amount equal to or lower than a predetermined lower limit value among the plurality of second light amounts calculated using the value indicating the ratio. The spectral sensitivity measuring device according to claim 1. The light amount ratio storage unit stores a plurality of values indicating the ratios assigned to the plurality of first light amounts,
The combination creating unit calculates a plurality of second light amounts corresponding to each of the plurality of first light amounts using a value indicating the ratio assigned to each of the plurality of first light amounts. The spectral sensitivity measuring apparatus according to claim 1 or 2. The first light source unit includes a first light emitting unit that emits the bias light, and a first adjustment unit that adjusts the amount of the bias light emitted by the first light emitting unit,
The spectral sensitivity measuring device further includes:
In a state in which the bias light of the first light amount stored in the bias light amount storage unit is irradiated to the reference detector in which the short-circuit current and the spectral sensitivity under a predetermined condition are specified. A short-circuit current output from the reference detector is defined as a first short-circuit current, and a plurality of the first light amounts stored in the bias light amount storage unit and a first predetermined formula are used. A first short-circuit current calculator that calculates a plurality of the first short-circuit currents corresponding to each of the one light quantity;
A value set in the first adjustment unit for the reference detector to output the first short-circuit current is set as a first set value, and the bias light is applied to the reference detector. The short-circuit current measured by the current measurement unit is compared with each of the plurality of first short-circuit currents calculated by the first short-circuit current calculation unit, and corresponds to each of the plurality of first short-circuit currents. A first set value calculation unit that calculates a plurality of the first set values;
A first set value storage unit that stores a plurality of the first set values calculated by the first set value calculation unit;
The emission control unit sets each of the plurality of first setting values stored in the first setting value storage unit in the first adjustment unit, and applies the bias to the first light source unit. The spectral sensitivity measuring apparatus according to any one of claims 1 to 3, which emits light. The second light source unit is generated by a second light emitting unit, a monochromatic light generating unit that generates the monochromatic light using the light emitted by the second light emitting unit, and the monochromatic light generating unit. A second adjusting unit for adjusting the amount of the monochromatic light,
The spectral sensitivity measuring device further includes:
For the reference detector, a short-circuit current output from the reference detector in a state in which the monochromatic light of the second light amount calculated by the combination creating unit is irradiated is set as a second short-circuit current, Using the second light quantity calculated by the combination creation unit, the second predetermined formula, and the spectral sensitivity of the reference detector, two or more of the monochromatic lights corresponding to two or more of the monochromatic lights having different wavelengths are used. A second short-circuit current calculator for calculating a second short-circuit current;
A value set in the second adjustment unit for the reference detector to output the second short-circuit current is set as a second setting value, and the monochromatic light is irradiated on the reference detector in the state where the reference detector is irradiated. Each of the two or more second short-circuit currents is compared with each of the two or more second short-circuit currents calculated by the second short-circuit current calculation unit by comparing the short-circuit current measured by the current measurement unit. A second set value calculation unit that calculates two or more second set values corresponding to
The second short circuit current calculation unit calculates two or more second short circuit currents for each of the plurality of second light quantities,
The second set value calculating unit calculates two or more second set values for each of the plurality of second light amounts,
The spectral sensitivity measuring device further includes:
Two or more second setting values for each of the plurality of second light amounts calculated by the second setting value calculation unit are set as a plurality of the second setting values, and a plurality of the second setting values are calculated. A second set value storage unit for storing the set value of
The emission control unit sets each of the plurality of second setting values stored in the second setting value storage unit in the second adjustment unit, and sets the single color in the second light source unit. The spectral sensitivity measuring apparatus according to claim 4 which emits light. The first adjusting unit is at least one of a first diaphragm and a first ND filter;
6. The spectral sensitivity measuring apparatus according to claim 5, wherein the second adjustment unit is at least one of a second diaphragm and a second ND filter.   The spectral sensitivity measuring device according to any one of claims 4 to 6, wherein the predetermined condition is STC which is a condition for evaluating performance of a solar cell.   The spectral sensitivity measuring apparatus according to claim 1, wherein the value indicating the ratio stored in the light amount ratio storage unit is a default value. An input section;
The spectral sensitivity according to any one of claims 1 to 7, further comprising a storage control unit that stores a value input by operating the input unit in the light amount ratio storage unit as a value indicating the ratio. measuring device. For each of the plurality of combinations created by the combination creation unit, the bias light emitted from the first light source unit and the monochromatic light emitted from the second light source unit under the control of the emission control unit In a state where the solar cell is overlaid with a lock-in amplifier having a function of detecting a short-circuit current due to the monochromatic light from among the short-circuit currents measured by the current measurement unit,
The spectral sensitivity measurement according to any one of claims 1 to 9, wherein the differential spectral sensitivity calculation unit calculates the differential spectral sensitivity using a short-circuit current due to the monochromatic light detected by the lock-in amplifier. apparatus.   The first diaphragm includes a first plate member having a plurality of through holes having different aperture ratios, and the second diaphragm has a second plate member having a plurality of through holes having different aperture ratios. The spectral sensitivity measuring apparatus of Claim 6 containing.

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