JP2013191468A - Irradiation light amount control device and solar simulator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an irradiation light amount control device and a solar simulator configured to prevent a change in spectrum distribution and surface uniformity of irradiation light, and to reduce manufacturing cost.SOLUTION: An irradiation light amount control device is provided with: a mechanical dimming filter which blocks a part of luminous flux from a light source and dims light; an integrator element which is installed on the light emitting side of the mechanical dimming filter and forms light of optically uniform distribution; and a light diffusing element which is inserted between the mechanical dimming filter and the integrator element, and has a light diffusing function and a high-order diffraction light component shielding function.

Description

  The present invention relates to an irradiation light amount control device and a solar simulator having a function of reducing irradiation light.

  Solar simulators for measuring photoelectric conversion characteristics by irradiating generated pseudo-sunlight, for example, solar cells such as solar battery panels, or performing deterioration characteristics tests are known. .

  In this type of solar simulator, the most common method of changing (decreasing) the amount of irradiation light is to change (reduce) the driving power of the light source (in many cases, the discharge lamp) used in the apparatus. is there. However, when the drive power is changed in this way, the uniformity within the irradiation surface does not change much, but the light emission characteristics of the light source itself change, so the spectral distribution of the irradiation light changes greatly.

  There is also a method of dimming by inserting a mechanical neutral density filter in front of an integrator (integrator optical system) which is an element for improving the uniformity of irradiation light without changing the driving power. However, in this case, since the incident angle of the light incident on the integrator is disturbed, there is a problem that the in-plane uniformity of the irradiated light is deteriorated. In particular, when the attenuation factor of the mechanical attenuating filter increases (for example, the transmittance is 50% or less), chromatic aberration due to diffraction occurs in the light incident on the integrator according to the value, and after passing through the integrator. There was a disadvantage that the spectral distribution and in-plane uniformity of the irradiated light changed significantly.

  Patent Document 1 discloses a machine configured by using light emitted from a light source unit or an integrator by a mesh filter made of a metal wire or a resin wire attached to a filter frame, a light shielding filter made of metal, a colored glass filter, or the like. A solar simulator is disclosed that attempts to improve light uniformity by passing through an optical neutral density filter.

JP 2007-311085 A

  However, even with the method of reducing the amount of irradiation light as described in Patent Document 1, there is a problem in that a considerable change occurs in the spectral distribution and in-plane uniformity of the irradiation light. The cost increases due to the special configuration.

  Accordingly, an object of the present invention is to provide an irradiation light amount control device and a solar simulator in which the spectral distribution and in-plane uniformity of irradiation light hardly change.

  Another object of the present invention is to provide an irradiation light quantity control device and a solar simulator that are inexpensive to manufacture.

  According to the present invention, a mechanical neutral density filter that blocks and attenuates a part of a light beam from a light source, and an optically uniform distribution of light that is provided on the light output side of the mechanical neutral density filter. And a light diffusing element inserted between the mechanical neutralizing filter and the integrator element and having a light diffusing function and a high-order diffracted light component blocking function of light are provided. .

  According to the present invention, the collimator lens further converts the incident light into parallel light provided on the light emitting side of the light source, the reflecting mirror that reflects the light of the light source, the above-described irradiation light amount control device, and the integrator element. A solar simulator comprising an element is provided.

  By using the mechanical neutral density filter, the amount of light incident on the integrator element can be arbitrarily reduced (changed). In that case, by inserting a light diffusing element having a light diffusing function and a light higher-order diffracted light component blocking function in front of the integrator element, the light passing through the mechanical neutralizing filter is diffused and the higher-order diffracted light is blocked. Since the light is incident on the integrator element, it is possible to prevent occurrence of color unevenness and image formation of the through-hole diameter. For example, when the mechanical neutral density filter is a punching type neutral density filter in which a plurality of through holes are provided in the light shielding plate, diffused light that does not contain high-order diffracted light enters the integrator element. This prevents the occurrence of color unevenness due to interference with each other and the formation of an image with a through-hole diameter. Even when the mechanical neutral density filter is an aperture type neutral density filter having a variable aperture, diffused light that does not contain higher-order diffracted light enters the integrator element, so color unevenness is caused by diffraction when the aperture diameter is reduced. It will never occur. Furthermore, when the mechanical neutral density filter is a ring type neutral density filter with a single through hole in the light shielding plate, diffused light that does not contain high-order diffracted light enters the integrator element. This prevents the occurrence of color unevenness due to diffraction.

  The light diffusing element is preferably an optical element having a light diffusing function and a high-order diffracted light blocking function.

  It is preferable that the integrator element is a compound eye lens type integrator element that creates a uniform light distribution by superimposing a plurality of light source images generated by a plurality of lenses while shifting their positions.

  It is also preferable that the distance between the light diffusing element and the integrator element is variable. By changing this distance, the amount of light incident on the integrator element changes minutely, and as a result, the attenuation rate can be finely adjusted.

  The mechanical neutral density filter is a punching type neutral density filter with a plurality of through holes in the light shielding plate, a diaphragm type neutral density filter with a variable aperture, or a single through hole in the light shielding plate. A ring-type neutral density filter is also preferable.

  According to the present invention, it is possible to reduce (change) the amount of light incident on the integrator element by using the mechanical neutral density filter. In that case, by inserting a light diffusing element in front of the integrator element, the light passing through the mechanical attenuating filter is diffused and the high-order diffracted light is blocked and made incident on the integrator element. The occurrence of image formation with a through-hole diameter can be prevented. For example, when the mechanical attenuating filter is a punching type attenuating filter, diffused light that does not contain high-order diffracted light enters the integrator element. It does not occur or image formation with a through-hole diameter does not occur. In addition, when the mechanical neutral density filter is an aperture type neutral density filter, diffused light that does not contain high-order diffracted light enters the integrator element, and color unevenness may occur due to diffraction when the aperture diameter is reduced. Disappear. Furthermore, when the mechanical neutral density filter is a ring type neutral density filter, diffused light that does not include high-order diffracted light enters the integrator element, and color unevenness may occur due to diffraction when the ring diameter is small. Disappear.

It is a figure which shows schematically the structure in one Embodiment of the solar simulator of this invention. It is a figure which shows schematically the structure of the irradiation light quantity control apparatus part of the solar simulator of FIG. FIG. 3 is an enlarged view of a part of FIG. 2. It is a figure explaining the apparatus structural example of the experiment which moved the light-diffusion element and changed the distance with an integrator element. It is a figure explaining the general operation | movement concept in one lens of an integrator element. It is a figure explaining the effect | action of an integrator element at the time of inserting a mechanical dark filter in the solar simulator of FIG. In the example of the solar simulator of FIG. 1, it is a figure explaining the illumination intensity measurement conditions. It is a graph showing the measurement result of the spectrum distribution characteristic of the irradiation light of the solar simulator at the time of the non-light reduction which does not insert a mechanical light reduction filter and a light diffusion element. It is a graph showing the measurement result of the spectrum distribution characteristic of the irradiation light of the solar simulator at the time of the light reduction which inserted only the mechanical light reduction filter. It is a graph showing the measurement result of the spectral distribution characteristic of the irradiation light of the solar simulator at the time of the light reduction which inserted the mechanical dark filter and the light diffusing element. It is a graph showing the measurement result of the spectrum distribution characteristic of the irradiation light of a solar simulator. It is a figure which shows schematically the structure of the irradiation light quantity control apparatus part in other embodiment of the solar simulator of this invention. It is a one part enlarged view of FIG. It is a figure which shows schematically the structure of the irradiation light quantity control apparatus part in further another embodiment of the solar simulator of this invention. It is a one part enlarged view of FIG. It is a figure which shows roughly the structure of an example of a solar simulator.

  FIG. 1 schematically shows the configuration of an embodiment of the solar simulator of the present invention, FIG. 2 schematically shows the configuration of the irradiation light quantity control device portion, and FIG. 3 shows a part of FIG. It is shown enlarged.

  In FIG. 1, 10 is a light source composed of, for example, a xenon discharge lamp, 11 is a light source reflector having an axial cross section of, for example, an ellipse or a parabola, disposed behind and around the light source 10, and 12 is directly from the light source 10. Light and reflected light from the light source reflecting mirror 11 are incident and reflected in a substantially vertical direction, for example, a first planar reflecting mirror made of aluminum, for example, 13 is incident reflected light from the first planar reflecting mirror 12. 14 is a mechanical attenuating filter, 14 is a light diffusing element to which the light emitted from the mechanical attenuating filter 13 is incident, 15 is an integrator element to which the light radiating from the light diffusing element 14 is incident, and 16 is a light radiating from the integrator element 15. The incident light is reflected in a substantially vertical direction, for example, a second planar reflecting mirror made of aluminum, for example, 17 is reflected light from the second planar reflecting mirror 16, and this light is collimated. Collimation lens for converting, 18 denotes light emitted collimation lens 17 is incident, for example, the irradiation surface is a solar cell surface, respectively.

  As shown in FIGS. 2 and 3, the mechanical neutral density filter 13, the light diffusing element 14, and the integrator element 15 constitute an irradiation light amount control device of the present invention.

  The mechanical neutral density filter 13 is a light shielding plate having a plurality of small openings (through holes 13b) for adjusting the amount of light, and changes the absolute amount of emitted light by spatially adjusting the light transmitting area. It is something to be made. In this embodiment, the mechanical neutral density filter 13 is a punching type neutral density filter in which a plurality of through holes 13b are provided in the light shielding plate 13a. More specifically, this punching type neutral density filter uses a stainless steel plate or aluminum plate having a length and width of 90 mm × 70 mm and a thickness of about 1 to 2 mm, and a plurality of round holes opened in a staggered manner. In particular, a light blocking part (non-opening part) is used as much as possible. In this embodiment, specifically, a punching metal having a desired light attenuation rate at 60 ° staggered at Punching Center Co., Ltd. is used. This 60 ° staggered punching metal is arranged in a staggered manner so that the angle formed by three lines connecting the centers of three adjacent round through holes is 60 °.

  The integrator element 15 is a compound eye lens (fly eye lens) type integrator optical system, and is an optical element known in this technical field. This integrator optical system is configured to create a uniform light distribution by superimposing a plurality of light source images generated by a plurality of lenses while shifting their positions.

  The light diffusing element 14 is an element having an original light diffusing function (also a light attenuating function) and a high-order diffracted light blocking function. That is, due to the optical frequency band cut-off characteristic provided in the light diffusing element 14, the high-order diffracted light component is cut off from the spatial frequency distribution of the incident light from the mechanical dark filter 13 and only the low-frequency component is transmitted. be able to. In addition, it has a circular diffusion characteristic that applies refraction instead of simple diffusion of light, and is configured to be capable of adjusting light attenuation with a large dynamic range and having a high transmittance of about 96%.

  When the individual aperture diameter of the mechanical neutral density filter 13 becomes smaller than the diameter of the individual lens of the integrator element 15, a diffracted light phenomenon occurs near the edge of the aperture of the mechanical neutral density filter 13. As a result, white light from the light source is spectrally separated to cause light dispersion. When the light diffusing element 14 is not provided, the spectral components separated by this diffraction are incident on the compound eye lens of the integrator element 15 at different angles for each spectrum. The light guided in the compound eye lens is guided in the emission direction by repeating total reflection, but if the angles incident on the compound eye lens are different from each other due to the difference in the wavelength of the light, the angle when exiting the compound eye lens will be different, Chromatic aberration occurs without producing parallel light. Thus, the light that has become non-parallel due to chromatic aberration is emitted from the integrator element 15, and is not corrected to parallel light by the collimation lens 17. As a result, it becomes impossible to irradiate a spectrum that approximates sunlight.

  On the other hand, as in this embodiment, a light diffusing element 14 that functions not only to diffuse light but also to function as a high-order diffracted light blocking filter is provided between the mechanical neutral density filter 13 and the integrator element 15. This makes it possible to remove chromatic aberration caused by high-order diffracted light generated near the edge of the opening of the mechanical neutral density filter 13. That is, by providing the light diffusing element 14 with the function of a spatial frequency filter, it is possible to remove high-order diffracted light and keep the uniformity and parallelism stable without causing a spectrum change.

  In addition, although the dimension of the light-diffusion element 14 in this embodiment changes with dimensions of the solar simulator and the dimension of the integrator element 15, it is about 60 mm x about 60 mm in length and width, and about 3 mm in thickness, for example. The light diffusing element 14 is a quartz plate low-angle light diffusing element, and is available as, for example, a Light Tempering Diffuser SOLGEEL Type Light Diffusing Diffuser from Luminit USA.

  This light diffusing element 14 has a function as a spatial frequency filter that blocks or reduces high-order diffracted light, and further has a function of diffusing light by refraction or the like, so that the emitted light is not accompanied by a diffraction phenomenon, Spectral dispersion does not occur. In addition, the light diffusing element 14 is preferably capable of diffusing light (coherent light and non-coherent light) in a range of about 10 to 30 ° with a half width, and can be diffused in a range of 10 to 20 °. More desirable. If the half-value width is too narrow, the chromatic aberration generated by the high-order diffracted light cannot be made uniform, and the chromatic aberration generated by the high-order diffracted light may not be eliminated when it is desired to reduce the light to the lowest level. Further, it is desirable that the light diffusing element 14 can form outgoing light having a substantially ideal Gaussian distribution. Furthermore, the light diffusing element 14 is desirably a structure in which an infinite number of concave and convex patterns are randomly arranged, and has the effect of canceling high-order diffracted light with each other by having random characteristics. The light diffusing element 14 is preferably resistant to heat and operable at a temperature of about 500 ° C.

The light diffusing element 14 can be moved in the optical axis direction by an unillustrated axial direction moving mechanism, whereby the distance d ₁ between the light diffusing element 14 and the integrator element 15 can be variably controlled. In this case, the positions of the mechanical neutral density filter 13 and the integrator element 15 are fixed. By changing the distance d ₁ (this also changes the distance d ₂ between the mechanical neutral density filter 13 and the light diffusing element 14), the amount of light incident on the integrator element 15 changes slightly. As a result, the light attenuation rate can be finely adjusted.

Actually, the distance d ₁ between the light diffusing element 14 and the integrator element 15 was changed, and the illuminance of the irradiation surface 18 was measured. FIG. 4 illustrates an apparatus configuration example used in the experiment. As shown in the drawing, a mechanical neutral density filter is not disposed on the light source side of the light diffusing element 14, and a wavelength conversion filter 21 is provided. Since this experiment is to confirm the relationship of the dimming rate with respect to the distance d ₁ , the mechanical dimming filter is omitted. A shutter 22 is disposed between the integrator element 15 and the light diffusing element 14.

First, when the distance d ₁ of the light diffusing element 14 with respect to the integrator element 15 was set to d ₁ = 29 mm, and the light attenuation rate was measured, it was 35%. When the light diffusing element 14 is moved and the distance d ₁ of the light diffusing element 14 ′ with respect to the integrator element 15 is set to d ₁ = 40 mm, the dimming rate is 40%.

From this, it can be seen that the light attenuation rate decreases as the light diffusing element 14 approaches the integrator element 15, and the light attenuation rate increases as the distance from the integrator element 15 increases. That is, the dimming ratio, the distance _{d 1} is the change about 10 mm, so that the change 5%.

  The collimation lens 17 is an optical element well known in the art for collimating incident light.

  Next, the operation of the solar simulator in this embodiment will be described.

  The light emitted from the light source 10 is reflected directly or by the light source reflecting mirror 11, is further reflected by the first planar reflecting mirror 12, and is incident on the mechanical neutral density filter 13 in the irradiation light quantity control device. The light that has entered the mechanical neutralization filter 13 passes through a plurality of small through-holes 13 b and is partially blocked to be attenuated, and is incident on the light diffusing element 14. The light emitted from the mechanical neutral density filter 13 is diffused by the light diffusing element 14 and is uniformly attenuated over the entire spectral range. Further, even if a diffracted light phenomenon occurs in the vicinity of the edge of the through hole 13b of the mechanical neutral density filter 13, since the high-order diffracted light is blocked by the light diffusing element 14, chromatic aberration occurs in the emitted light. Absent. The light emitted from the light diffusing element 14 is incident on the integrator element 15, and a large number of light source images are superimposed and shifted by the compound eye lens, thereby forming a uniform light distribution. The light having a uniform and uniform spectral distribution formed in this way is reflected by the second plane reflecting mirror 16 and then converted into completely parallel light by the collimation lens 17, and then the surface of the solar battery cell. The irradiation surface 18 is irradiated.

  FIG. 5 illustrates a general operation concept in one lens of the integrator element 15 which is a compound eye lens.

In the uniform irradiation optical system, the greatest purpose is to extract the light beam of the light source 10 to the maximum and remove the image of the light source 10 (for example, the image of the lamp electrode), and the light source reflector 11 and integrator having an elliptical or parabolic axial section. Element 15 is usually used. When the light beam collected by only the light source reflecting mirror 11 without using the integrator element 15 is irradiated as a parallel light beam by the collimation lens 17, an image of the lamp electrode appears on the irradiation surface. Therefore, in order to remove such an image, it is necessary to use the integrator element 15. In order to use such an integrator element 15 effectively, only the light quantity loss in the integrator element 15 is suppressed by making the emission angle θ _{OUT the} same angle as the incident angle θ _IN from the light source reflecting mirror 11. Instead, the integrator element 15 is designed so that no image is formed on the exit side by forming an image of the lamp electrode inside the integrator element 15.

In FIG. 5, when O ₁ is the sphere center of the incident-side spherical surface 15a of one lens of the integrator element 15 and O ₂ is the sphere center of the exit-side spherical surface 15b, the incident-side focal length f ₁ is f ₁ = O _1. × 2, The focal length f ₂ on the emission side is O ₂ × 2. From the lens formula 1 / a + 1 / b = 1 / f, when the object distance on the exit side is a <f (shorter than the focal length), the image distance on the exit side is b (−). The outgoing light is not condensed on the outgoing surface 15b, is emitted in a spread, and is never condensed.

  FIG. 6 illustrates the operation of the integrator element 15 when the mechanical dark filter 13 is inserted in front (light source side) in the solar simulator of this embodiment.

  For the purpose of dimming on the light source 10 side of the integrator element 15 designed under the above-described conditions, when the mechanical dark filter 13 by the punching type dark filter is disposed, the mechanical light attenuation is placed in front of the integrator element 15. An image of the through hole 13b of the filter 13 is generated as a secondary light source.

In this case, as shown in FIG. 6, from the law of refraction, the incident angle θ _{IN at the} point P becomes θ _IN = θ ₁ + α, and is incident from the air into the medium having the refractive index N ₁ from the point P. Becomes θ ₁ −γ. On the other hand, the incident angle on the exit surface 15b is represented by θ ₂ + γ, and the refraction angle from the exit surface 15b is represented by θ ₂ + β. In this case, the angle incident on the integrator element 15 from the image of the through hole 13b of the mechanical neutral density filter 13 varies, but when the incident angle is large, the light incident on the P point is a medium having a refractive index N ₁ . Refracted (air to quartz) does not form an image on the optical axis, but forms an image on the exit surface 15b and refracts again (from quartz to air), and forms an image outside the exit surface 15b. This phenomenon is based on the optical type 1 / a + 1 / b = 1 / f, and 1 / b = 1 / f holds when the object distance on the exit surface 15b is assumed to be ∞ or 0. Therefore, the image distance on the exit surface side is (+), And an image is formed on the right side of the emission surface 15b.

  The following experiment was conducted to confirm this phenomenon.

(Experimental equipment and measuring instrument)
Solar simulator: Solar simulator manufactured by Yamashita Denso Co., Ltd. (YSS-
1800AA), specification AAA
Reference solar cell: silicon cell for 400 nm to 1100 nm,
Calibration value = 142.6 mA
Digital multimeter: Agilent Technologies Inc. (34401A),
Used to measure the short-circuit current of the reference solar cell. Illuminance meter for measuring uneven illuminance: Thermopile (φ6mm) illuminance manufactured by Yamashita Denso Co., Ltd.
Meter (MIR-101Q), JIS standard incident angle ± 15 °
Illuminance meter for measuring illuminance fluctuation: Illuminometer manufactured by USHIO INC. (UIT-101)
Center frequency 436nm

(Dimming rate)
The illuminance was set to a standard 1000 W / m ² (= 1 SUN) (142.6 mA) with a reference solar cell. The illuminance reduced when the mechanical neutral filter 13 by the punching type neutral density filter 13 is set is 106 W / m ² (about 0.1 SUN), and the mechanical neutral density filter 13 by the punching type neutral density filter 13 The reduced illuminance when the light diffusing element 14 by the quartz light diffusing element was disposed behind was 70.2 W / m ² (about 0.07 SUN).

(experimental method)
As shown in FIG. 7, an effective area 18a of 180 mm × 180 mm (A □) is set on the irradiation surface 18 400 mm below the lens hood in the solar simulator. With respect to the 17 measurement positions 19 (positions 1 to 17) of the effective area 18a according to the JIS standard, illuminance measurement (illuminance unevenness measurement) is performed by the above-described illuminance meter for measuring unevenness in illumination that does not block the light within the incident angle ± 15 °. We went sequentially. At the same time, the illuminance meter 20 for measuring illuminance fluctuation was used to measure the illuminance at one point in the effective area 18a, and the fluctuation of light during illuminance unevenness measurement was measured.

(Measurement result)
Table 1 shows the measurement results at the time of non-dimming in which the mechanical neutral density filter 13 and the light diffusing element 14 are not inserted. The measurement results by the illuminance meter for measuring illuminance unevenness at the measurement positions 1 to 17 are shown as measured illuminance values E _i (i = 1 to 17), and the measurement results by the illuminance meter 20 for measuring illuminance fluctuation at each measurement. Is shown as a variable illuminance value e _i (i = 1 to 17). The measured illuminance value E _i compensated for the reference varying illuminance value e _{1 at} the measurement position 1 is shown as a relative illuminance value E _i ′ (i = 1 to 17). That is, the relative illuminance value E _i ′ is calculated by E _i ′ = (e ₁ / e _i ) × E _i .

The in-plane uniformity E _uni is _calculated from the 17 relative illuminance values E _i ′ obtained in this way, E _uni = (E _i ′ max−E _i ′ min) / (E _i ′ max + E _i ′ min) × 100 Calculated from Here, E _i 'max is the maximum value of the relative illuminance value E _i ', and E _i 'min is the minimum value of the relative illuminance value E _i '. The obtained in-plane uniformity E _uni was E _uni = 1.46 (%).

  Next, the same measurement was performed at the time of dimming with the mechanical neutral density filter 13 inserted by a punching type neutral density filter. The measurement results are shown in Table 2.

The in-plane uniformity E _uni was calculated from the 17 relative illuminance values E _i ′ thus obtained in the same manner as described above. The obtained in-plane uniformity E _uni was E _uni = 4.93 (%).

  Next, the same measurement was performed at the time of dimming by inserting the light diffusing element 14 by the quartz light diffusing element behind the mechanical attenuating filter 13 by the punching type neutral density filter. The measurement results are shown in Table 3.

The in-plane uniformity E _uni was calculated from the 17 relative illuminance values E _i ′ thus obtained in the same manner as described above. The obtained in-plane uniformity E _uni was E _uni = 1.86 (%).

From the above experimental results, the in-plane uniformity E _uni is reduced from 1.46 (%) to _4.4 by inserting the mechanical attenuating filter 13 by the punching type attenuating filter in front of the integrator element 15 (light source side). However, this is because an image (secondary light source image) of the punching-type neutral density filter in front of the integrator element 15 is generated, and an image is formed on the output side of the integrator element 15 as described above. Prove that you are imaged. The in-plane uniformity E _uni is improved from 4.93 (%) to 1.86 (%) by inserting the light diffusing element 14 by the quartz light diffusing element behind the mechanical neutral density filter 13. This demonstrates that the image on the exit side of the integrator element 15 has been removed.

  As described above, according to the present embodiment, light having a uniform spectral distribution is irradiated onto the irradiation surface 18. In order to confirm this point, the following experiment was performed.

(Experimental equipment and measuring instrument)
Solar simulator: Solar simulator manufactured by Yamashita Denso Co., Ltd. (YSS-
1800AA), specification AAA
Reference solar cell: silicon cell for 400 nm to 1100 nm,
Calibration value = 142.6 mA
Digital multimeter: Agilent Technologies Inc. (34401A),
Used to measure the short-circuit current of the reference solar cell Multipurpose spectroradiometer: Opt-Research Corporation (MSR-7000)
Illuminance meter for measuring illuminance fluctuation: Illuminometer manufactured by USHIO INC. (UIT-101)
Center frequency 436nm

(experimental method)
As shown in FIG. 7, an effective area 18a of 180 mm × 180 mm (A □) is set on the irradiation surface 18 400 mm below the lens hood in the solar simulator. The standard solar cell was used to set the illuminance of standard 1000 W / m ² (= 1 SUN) (142.6 mA), and the spectral distribution was measured for the effective region 18a using the multipurpose spectroradiometer described above. Actually, the spectral distribution is measured at some positions (positions 1, 5 and 16) of the 17 measurement positions 19 (positions 1 to 17) of the JIS standard of the effective region 18a, and the intensity characteristics and Spectral agreement was determined. The dimming amount was corrected by multiplying the measured value by the dimming magnification measured with the illuminometer.

(Measurement result)
The measurement result at the time of non-dimming without inserting the mechanical neutral density filter 13 and the light diffusing element 14 is shown in FIG. At the time of non-dimming (1 SUN), almost the same spectral intensity distribution is obtained at any of the positions 1, 5, and 16. On the other hand, FIG. 9 shows the measurement result at the time of dimming with the mechanical neutralizing filter 13 inserted by the punching type neutral density filter. At the time of this dimming, the spectral intensity distribution at positions 5 and 16 is considerably different from the spectral intensity distribution at position 1 of non-dimming (1 SUN). On the other hand, FIG. 10 shows a measurement result at the time of dimming by inserting the mechanical neutral density filter 13 by the punching type neutral density filter and the light diffusing element 14 by the quartz light diffusing element. Even at the time of dimming, by inserting the light diffusing element 14, the spectral intensity distribution at the positions 5 and 16 has a characteristic that approximates the spectral intensity distribution at the position 1 of non-dimming (1 SUN), By inserting the light diffusing element 14 made of a quartz light diffusing element behind the mechanical neutral density filter 13, the spectral intensity distribution is greatly improved and hardly changes each other at each position.

  Further, similar results are obtained with respect to the degree of spectral coincidence as shown in FIG. In FIG. 11, the horizontal axis represents the wavelength (nm) and the vertical axis represents the degree of spectrum matching. According to the JIS standard, it is determined that the upper limit value of the spectrum matching degree is 1.25 and the lower limit value is 0.75. At the time of non-dimming (1 SUN) in which the mechanical neutral density filter 13 and the light diffusing element 14 are not inserted, the spectral coincidence is good at any of the positions 1, 5 and 16. It can be seen that at the positions 5 and 16, the spectral coincidence degree deteriorates and the spectral distribution changes at the time of dimming with the mechanical neutralizing filter 13 by the punching type neutral density filter inserted. When the mechanical attenuating filter 13 by the punching type attenuating filter and the light diffusing element 14 by the quartz light diffusing element are inserted, the spectral coincidence is greatly improved, and the spectral characteristic of the spectral intensity distribution (1SUN) at the position 1 is improved. It can be seen that they are approximate.

  Thus, it has been proved by experiments that the deterioration of the in-plane distribution due to the light attenuation related to the in-plane uniformity can be improved by using the light diffusing element 14 of the quartz light diffusing element. On the other hand, regarding the spectral intensity distribution, the use of the light diffusing element 14 made of a quartz light diffusing element greatly improves the degree of spectral matching. That is, it was proved by experiments that the in-plane distribution and the partial color unevenness can be improved by using the light diffusing element 14 as in the present embodiment.

  As described above, according to the present embodiment, the amount of light incident on the integrator element 15 can be reduced by using the mechanical neutral density filter 13 that is a punching type neutral density filter. In that case, by inserting the light diffusing element 14 in front of the integrator element 15, the light passing through the mechanical attenuating filter 13 is diffused and the high-order diffracted light is blocked and made incident on the integrator element 15. Generation of unevenness and image formation of the through hole diameter of the mechanical neutral density filter 13 can be prevented. In this way, diffused light that does not contain high-order diffracted light enters the integrator element 15, so that interference occurs due to diffraction when passing through each through-hole, resulting in color unevenness, or image formation with a through-hole diameter. There is no longer to do. As a result, parallel light with uniform in-plane and no chromatic aberration is irradiated onto the irradiation surface 18 which is, for example, the surface of the solar battery cell.

  FIG. 12 schematically shows the configuration of the irradiation light quantity control device part in another embodiment of the solar simulator of the present invention, and FIG. 13 shows an enlarged part of FIG.

  The configuration of the solar simulator of the present embodiment excluding the mechanical light reduction filter of the irradiation light amount control device is exactly the same as that of the embodiment shown in FIG. Therefore, in FIG. 12 and FIG. 13, the same reference numerals are used for the same components as in the embodiment of FIG. 1, and the description thereof is omitted.

  As shown in FIGS. 12 and 13, the reflected light from the first planar reflecting mirror 12 is incident on the mechanical dark filter 23, and the outgoing light from the mechanical dark filter 23 is incident on the light diffusing element 14. . The light emitted from the light diffusing element 14 is incident on the integrator element 15, and the light emitted from the integrator element 15 is incident on the second planar reflecting mirror 16 and reflected. The mechanical neutral density filter 23, the light diffusing element 14, and the integrator element 15 constitute the irradiation light amount control device of the present invention.

  The mechanical neutral density filter 23 is a light-shielding plate having a single variable diaphragm 23c for adjusting the amount of light, and the absolute amount of emitted light is changed by spatially adjusting the area through which light is transmitted. It is something to be made. In this embodiment, the mechanical neutral density filter 23 is constituted by a diaphragm type neutral density filter provided with a variable diaphragm 23c whose opening diameter (diaphragm diameter) is adjusted by movable light shielding plates 23a and 23b. Yes. More specifically, this diaphragm-type neutral density filter has a light shielding plate 23a in which a stainless steel plate or an aluminum plate having a length and width of 90 mm × 70 mm and a thickness of about 1 to 2 mm is divided into two parts, and each is provided with a V-shaped cutout. And the opening diameter of the variable aperture 23c is adjusted by adjusting the separation distance of the notches of 23b. The shape of the notch is not limited to a V shape, and may be a semicircular shape or other shapes.

  When the aperture diameter of the variable diaphragm 23c of the mechanical neutral density filter 23 becomes smaller than the diameter of each lens of the integrator element 15, the diffracted light near the edge of the variable diaphragm 23c of the mechanical neutral density filter 23. A phenomenon occurs, whereby white light from the light source is spectrally separated and light dispersion occurs. When the light diffusing element 14 is not provided, the spectral components separated by this diffraction are incident on the compound eye lens of the integrator element 15 at different angles for each spectrum. The light guided in the compound eye lens is guided in the emission direction by repeating total reflection, but if the angles incident on the compound eye lens are different from each other due to the difference in the wavelength of the light, the angle when exiting the compound eye lens will be different, Chromatic aberration occurs without producing parallel light. Thus, the light that has become non-parallel due to chromatic aberration is emitted from the integrator element 15, and is not corrected to parallel light by the collimation lens 17. As a result, it becomes impossible to irradiate a spectrum that approximates sunlight.

  On the other hand, as in this embodiment, a light diffusing element 14 that functions not only to diffuse light but also as a high-order diffracted light blocking filter is provided between the mechanical neutral density filter 23 and the integrator element 15. This makes it possible to remove chromatic aberration caused by high-order diffracted light generated near the edge of the single variable stop 23c of the mechanical neutral density filter 23. That is, by providing the light diffusing element 14 with the function of a spatial frequency filter, it is possible to remove high-order diffracted light and keep the uniformity and parallelism stable without causing a spectrum change.

  Next, the operation of the solar simulator in this embodiment will be described.

  The light emitted from the light source 10 is reflected directly or by the light source reflecting mirror 11, further reflected by the first planar reflecting mirror 12, and is incident on the mechanical neutral density filter 23 in the irradiation light quantity control device. The light that has entered the mechanical neutralizing filter 23 is transmitted through the single variable aperture 23 c, so that part of the light is blocked and attenuated, and is incident on the light diffusing element 14. The light emitted from the mechanical neutralizing filter 23 is diffused by the light diffusing element 14 and is uniformly attenuated over the entire spectral range. Further, even if a diffracted light phenomenon occurs in the vicinity of the edge of the variable stop 23c of the mechanical neutral density filter 23, high-order diffracted light is blocked by the light diffusing element 14, so that chromatic aberration occurs in the emitted light. Absent. The light emitted from the light diffusing element 14 is incident on the integrator element 15, and a large number of light source images are superimposed and shifted by the compound eye lens, thereby forming a uniform light distribution. The light having a uniform and uniform spectral distribution formed in this way is reflected by the second plane reflecting mirror 16 and then converted into completely parallel light by the collimation lens 17, and then the surface of the solar battery cell. The irradiation surface 18 is irradiated.

  As described above, according to the present embodiment, the amount of light incident on the integrator element 15 can be reduced by using the mechanical dark filter 23 by the diaphragm type dark filter. In that case, by inserting the light diffusing element 14 in front of the integrator element 15, the light passing through the mechanical neutralizing filter 23 is diffused and the high-order diffracted light is blocked and made incident on the integrator element 15. Generation of unevenness and image formation of the aperture diameter of the diaphragm of the mechanical neutralizing filter 23 can be prevented. In this way, diffused light that does not include higher-order diffracted light enters the integrator element 15, so that interference occurs with each other due to diffraction when passing through the variable aperture 23 c, and color imaging occurs on the variable aperture 23 c. It will not be. As a result, parallel light with uniform in-plane and no chromatic aberration is irradiated onto the irradiation surface 18 which is, for example, the surface of the solar battery cell.

  FIG. 14 schematically shows a configuration of an irradiation light amount control device portion in still another embodiment of the solar simulator of the present invention, and FIG. 15 shows a part of FIG. 14 in an enlarged manner.

  The configuration of the solar simulator of the present embodiment excluding the mechanical light reduction filter of the irradiation light amount control device is exactly the same as that of the embodiment shown in FIG. Therefore, in FIGS. 14 and 15, the same reference numerals are used for the same components as those in the embodiment of FIG. 1, and the description thereof is omitted.

  As shown in FIGS. 14 and 15, the reflected light from the first planar reflecting mirror 12 is incident on the mechanical neutral density filter 33, and the outgoing light of the mechanical neutral density filter 33 is incident on the light diffusing element 14. . The light emitted from the light diffusing element 14 is incident on the integrator element 15, and the light emitted from the integrator element 15 is incident on the second planar reflecting mirror 16 and reflected. The mechanical neutral density filter 33, the light diffusing element 14, and the integrator element 15 constitute an irradiation light amount control device of the present invention.

  The mechanical neutral density filter 33 is a light shielding plate 33a having a single through hole 33b for adjusting the amount of light, and emits light by spatially setting an area through which light is transmitted by the opening diameter of the through hole 33b. It sets the absolute amount of light. In the present embodiment, the mechanical neutral density filter 33 is a ring type neutral density filter provided with a fixed through hole 33b. More specifically, this ring-type neutral density filter is configured by providing a single through hole 33b in the central portion of a light shielding plate 33a made of a stainless steel plate or aluminum plate having a length and width of 90 mm × 70 mm and a thickness of about 1 to 2 mm. ing. The shape of the through hole 33b is not limited to a circular shape, and may be other shapes.

  When the aperture diameter of the through hole 33b of the mechanical neutral density filter 33 is set smaller than the diameter of each lens of the integrator element 15, diffraction occurs near the edge of the through hole 33b of the mechanical neutral density filter 33. A light phenomenon occurs, whereby white light from the light source is spectrally separated to cause light dispersion. When the light diffusing element 14 is not provided, the spectral components separated by the diffraction are incident on the compound eye lens of the integrator element 15 at different angles for each spectrum. The light guided in the compound eye lens is guided in the emission direction by repeating total reflection, but if the angles incident on the compound eye lens are different from each other due to the difference in the wavelength of the light, the angle when exiting the compound eye lens will be different, Chromatic aberration occurs without producing parallel light. Thus, the light that has become non-parallel due to chromatic aberration is emitted from the integrator element 15, and is not corrected to parallel light by the collimation lens 17. As a result, it becomes impossible to irradiate a spectrum that approximates sunlight.

  On the other hand, as in this embodiment, a light diffusing element 14 that functions not only to diffuse light but also to function as a high-order diffracted light blocking filter is provided between the mechanical neutral density filter 33 and the integrator element 15. As a result, it is possible to remove chromatic aberration caused by high-order diffracted light generated in the vicinity of the edge of the single through hole 33b of the mechanical neutral density filter 33. That is, by providing the light diffusing element 14 with the function of a spatial frequency filter, it is possible to remove high-order diffracted light and keep the uniformity and parallelism stable without causing a spectrum change.

  The operations of the mechanical neutral density filter 33 and the light diffusing element 14 in this embodiment are the same as those in the embodiment of FIG.

  Next, the operation of the solar simulator in this embodiment will be described.

  The light emitted from the light source 10 is reflected directly or by the light source reflecting mirror 11, is further reflected by the first planar reflecting mirror 12, and is incident on the mechanical neutral density filter 33 in the irradiation light quantity control device. The light that has entered the mechanical neutral filter 33 is transmitted through the single through-hole 33 b, so that part of the light is blocked and attenuated, and is incident on the light diffusing element 14. The light emitted from the mechanical neutralizing filter 33 is diffused by the light diffusing element 14 and is uniformly attenuated over the entire spectral range. Further, even if a diffracted light phenomenon occurs in the vicinity of the edge of the through hole 33b of the mechanical neutral density filter 33, the light diffusion element 14 blocks high-order diffracted light, so that chromatic aberration occurs in the emitted light. Absent. The light emitted from the light diffusing element 14 is incident on the integrator element 15, and a large number of light source images are superimposed and shifted by the compound eye lens, thereby forming a uniform light distribution. The light having a uniform and uniform spectral distribution formed in this way is reflected by the second plane reflecting mirror 16 and then converted into completely parallel light by the collimation lens 17, and then the surface of the solar battery cell. The irradiation surface 18 is irradiated.

  As described above, according to the present embodiment, the amount of light incident on the integrator element 15 can be reduced by using the mechanical neutral density filter 33 using a ring type neutral density filter (the maximum attenuation ratio is 20). %degree). In that case, by inserting the light diffusing element 14 in front of the integrator element 15, the light passing through the mechanical neutralizing filter 33 is diffused and the high-order diffracted light is blocked and made incident on the integrator element 15. Generation of unevenness and image formation of the opening diameter of the through hole 33b of the mechanical neutral density filter 33 can be prevented. In this way, diffused light that does not contain higher-order diffracted light enters the integrator element 15, so that interference occurs with each other due to diffraction when passing through the through-hole 33 b, and color image formation occurs in the through-hole 33 b. It will not be. As a result, parallel light with uniform in-plane and no chromatic aberration is irradiated onto the irradiation surface 18 which is, for example, the surface of the solar battery cell.

  FIG. 16 is a diagram schematically showing a configuration of an example of a solar simulator.

  In the figure, 10 is a light source composed of, for example, a xenon discharge lamp, 11 is a light source reflecting mirror having an axial cross section of, for example, an ellipse or a parabola, and 12 is directly from the light source 10. Light and reflected light from the light source reflecting mirror 11 are incident and reflected in a substantially vertical direction, for example, a first planar reflecting mirror made of aluminum, and 15 is reflected light from the first planar reflecting mirror 12. The integrator element 16 receives the light emitted from the integrator element 15 and reflects it in a substantially vertical direction. For example, a second planar reflecting mirror made of aluminum, 44 receives the reflected light from the second planar reflecting mirror 16. The low-angle light diffusing element 17 is a collimation lens that converts the light emitted from the low-angle light diffusing element 44 into parallel light, and 18 is the light emitted from the collimation lens 17. It is the, for example, shows the irradiation surface is a solar cell surface, respectively.

  When it is not necessary to consider the parallelism of the light finally irradiated to the irradiation surface 18, a low-angle light diffusing element 44 is disposed between the integrator element 15 and the collimation lens 17, as shown in FIG. The light attenuation rate can be changed by changing the arrangement distance, and the light attenuation rate can be adjusted by setting the diffusion rate of the low-angle light diffusing element 44.

  All the embodiments described above are illustrative of the present invention and are not intended to be limiting, and the present invention can be implemented in other various modifications and changes. Therefore, the scope of the present invention is defined only by the claims and their equivalents.

DESCRIPTION OF SYMBOLS 10 Light source 11 Light source reflective mirror 12 1st plane reflective mirror 13, 23, 33 Mechanical neutral density filter 13a, 23a, 23b, 33a Light-shielding plate 13b, 33b Through-hole 14 Light diffusing element 15 Integrator element 16 2nd plane reflection Mirror 17 Collimation lens 18 Irradiation surface 18a Effective area 19 Measurement position 20 Illuminance meter for measuring illuminance fluctuation 21 Wavelength conversion filter 22 Shutter 23c Variable aperture

Claims (7)

  A mechanical attenuating filter that cuts off a part of the light flux from the light source and dimming, and an integrator element that is provided on the light emitting side of the mechanical attenuating filter and creates light with an optically uniform distribution; And a light diffusing element inserted between the mechanical neutral density filter and the integrator element and having a light diffusing function and a light higher-order diffracted light component blocking function.   The integrator element according to claim 1, wherein the integrator element is a compound eye lens type integrator element that creates a uniform light distribution by superimposing a plurality of light source images generated by a plurality of lenses while shifting their positions. Irradiation light quantity control device.   3. The irradiation light amount control device according to claim 1, wherein the mechanical neutral density filter is a punching type neutral density filter in which a plurality of through holes are provided in a light shielding plate.   The irradiation light quantity control device according to claim 1, wherein the mechanical neutral density filter is an aperture type neutral density filter having a variable aperture.   The irradiation light quantity control device according to claim 1, wherein the mechanical neutral density filter is a ring type neutral density filter in which a single through hole is provided in a light shielding plate.   6. The irradiation light amount control device according to claim 1, wherein a distance between the light diffusing element and the integrator element is variable.   A light source, a reflecting mirror that reflects light from the light source, an irradiation light amount control device according to any one of claims 1 to 6, and a light emission side of the integrator element in the irradiation light amount control device. A solar simulator comprising a collimator lens element that converts incident light into parallel light.

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