JP6635849B2 - Optical measuring device and measuring method - Google Patents

Description

  The present invention relates to an optical measuring device and a measuring method.

  2. Description of the Related Art Conventionally, a technique has been put to practical use in which solar radiation is reflected in a sky direction above a horizontal plane by providing a retroreflective property to a building skin such as a window film or a wall material. It has been confirmed that such a technique can reduce the amount of solar radiation reflected in the direction of the ground surface, and can provide a certain effect in alleviating the heat island (HI) phenomenon and improving the thermal environment (for example, Patent Documents 1 and 2). reference).

  Since retroreflection is a phenomenon in which incident light is reflected in the incident direction, it is necessary to measure reflected light on an incident optical path in order to measure reflected light due to retroreflection. However, if the light receiver is placed on the incident light path, the light is blocked by the light receiver. Therefore, by installing an optical element such as a half mirror that divides the light beam on the incident light path and changing the traveling direction of the light reflected to the incident light source side, the light reflected by the light receiver installed at a position where the incident light is not blocked Measuring reflected light has been conventionally performed (for example, see Patent Document 3). The light reflected by such retroreflection is measured using a goniometer. The measured value corresponds to the solid angle reflectance at a specific reflection angle, and is used to represent the reflection angle characteristic.

  On the other hand, for measurement of the reflectance in a wide angle range, a measurement system using an integrating sphere is generally used, and reflected light measurement at a high angle incidence, which is equivalent to the above-described solar radiation on the building skin, is possible. Some have been proposed (for example, see Patent Document 4).

JP 2010-160467 A JP 2011-137342 A JP-T-2013-508749 JP 2007-033334 A

  By the way, in the retroreflection characteristics of the building outer skin, diffusion and separation of reflected light occur depending on the structure of the reflection surface and the like. Therefore, in quantifying the improvement effect of the HI phenomenon, as shown in FIG. 1, it is necessary to measure the light reflected in all directions (sky side angle range) above the sky plane (sky) and obtain the reflectance. Is done.

  When measuring the reflected light widely distributed in the three-dimensional direction as described above by the measuring method using the conventional goniometer, since the receiver is small relative to the distribution of the reflected light, the angle of the receiver is continuously changed. And a method of calculating the reflectance by integrating the measured values. However, in this case, it takes time to measure a wide angle range, and it is difficult to accurately measure the angle because a mechanical error at the time of angle feed and an overlap or omission of measurement areas are likely to occur. On the other hand, the reflection measurement with the integrating sphere mainly measures the omnidirectional reflection (hemispherical reflection) of the sample, and cannot measure the reflectance in a specific angle range. As described above, conventionally, it was possible to measure the solid angle reflectance and the hemispherical reflectance by different measurement methods, but it was not possible to measure the reflectance in a desired angle range.

  An object of the present invention, which has been made in view of the above problems, is to provide an optical measuring device and a measuring method capable of measuring a reflectance in a desired angle range.

  In order to solve the above-described problem, an optical measuring device according to the present invention has an opening, an integrating sphere through which incident light from an external light source is incident, and a surface inside the integrating sphere. Of the sample placed exposed, of the plane including the normal at the position where the incident light is incident, through a boundary surface that is any plane other than the incident surface including the incident light and the specular reflected light, A reflected light absorber installed to absorb omnidirectional reflected light on the side opposite to the incident light.

  It is preferable that the optical measurement device according to the present invention further includes a detachable half mirror that covers the entire opening.

  In addition, it is preferable that the optical measurement device according to the present invention further includes a transmitted light absorber that is provided on the back surface side of the sample and absorbs transmitted light transmitted through the sample.

  Further, in the optical measuring device according to the present invention, it is preferable that the transmitted light absorber is formed of a box-shaped body having an opening through which the transmitted light transmitted through the sample enters.

  Further, in order to solve the above-described problem, a measurement method according to the present invention is a measurement method using the optical measurement device, wherein the sample is arranged at a position where the incident light does not enter in the integrating sphere, and Arranging a standard reflector at a position where the incident light is incident, and obtaining a reference reflected light amount; exchanging the sample and the standard reflector to obtain an incident side omnidirectional reflected light amount; Obtaining an incident-side omnidirectional reflectance based on the amount of reflected light and the amount of incident-side omnidirectional reflected light.

  In order to solve the above-mentioned problem, a measuring method according to the present invention is a measuring method using the optical measuring device, wherein the reflectance of the half mirror is ρh, and the measured reflectance when the half mirror is installed is Rh. Assuming that the measured reflectance when the half mirror is not installed is Rn, the dissipated light-compensated reflectance that compensates for the retroreflected light that escapes from the opening to the outside of the integrating sphere is represented by the formula: Rn + (Rh−Rn) / Obtained by ρh.

  According to the optical measuring device and the measuring method according to the present invention, it is possible to measure the reflectance in a desired angle range.

It is a figure which shows the outline | summary of upward reflection. It is a schematic diagram showing the optical measuring device concerning one embodiment of the present invention. It is the schematic which shows a reflected light absorber. It is a figure showing other examples of a reflected light absorber. It is a figure showing an example using a sample with large diffusivity. It is a figure explaining a transmitted light absorber. It is a figure explaining a box-shaped transmitted light absorber. It is the schematic which shows the absorption of the reflected light from the wall surface of the integrating sphere by an absorber. It is a figure explaining the measuring method of the light quantity loss by an absorber. FIG. 2 is a cross-sectional view showing a sample A. It is a figure which shows the measurement result of the absorptivity of the absorber which becomes a measurement error. It is a figure showing the measurement result of hemispherical reflectance. It is a figure explaining the measuring method which replaces a standard reflector and a sample. FIG. 3 is a diagram illustrating reflected light on a sample A. FIG. 3 is a diagram illustrating reflected light on a sample A. FIG. 9 is a diagram showing measurement results of hemispherical reflectance depending on whether or not a half mirror is installed in an opening according to Measurement Example 1. FIG. 7 is a diagram illustrating measurement results of each reflectance of a sample A according to Measurement Example 1. FIG. 9 is a diagram illustrating measurement results of each reflectance of a sample B according to Measurement Example 1. FIG. 9 is a diagram illustrating measurement results of hemispherical reflectance depending on whether or not a half mirror is installed in an opening according to Measurement Example 2. FIG. 4 is a diagram illustrating a reflectance of a half mirror. It is a figure which shows the measurement result of the scattered light compensation reflectance and the reflectance without scattered light.

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

(First embodiment)
As shown in FIGS. 2A and 2B, the optical measurement device 1 according to one embodiment of the present invention includes an integrating sphere 10, a reflected light absorber 30, and a light receiving unit 40.

  The integrating sphere 10 has an opening 11. The integrating sphere 10 can receive incident light L from an external light source through the opening 11. A half mirror that covers the entirety of the opening 11 is detachably installed in the opening 11.

  Here, the optical measurement device 1 can be installed so that the sample 100 is exposed inside the integrating sphere 10. Specifically, the optical measurement apparatus 1 can place the sample 100 at a position where incident light L from an external light source is directly incident on the sample surface 110 at an incident angle θ (for example, 60 ° in FIG. 2). . As shown in FIG. 2A, the sample 100 may be installed so as to cover an opening provided on the bottom surface of the integrating sphere 10 and communicating with the outside. In this case, the sample 100 may be installed on the sample stage 20, for example, as shown in FIG. When the integrating sphere 10 has no opening in the bottom surface, the sample 100 may be set on the bottom surface inside the integrating sphere 10.

  The reflected light absorber 30 is formed of a light absorbing film or the like, and is disposed on the sample surface 110 of the sample 100 so as to absorb the reflected light in all directions on the specular reflection side of the sample 100. Here, the specular reflection side omnidirectional refers to any plane other than the incident surface including the incident light L and the specular reflected light among the planes including the normal line O at the position where the incident light L on the sample surface 110 is incident. When the boundary surface P is used, it means all directions on the opposite side to the incident light via the boundary surface P.

  For example, as shown in FIG. 3, the reflected light absorber 30 includes a slope 31 intersecting an incident surface including the incident light L and the specular reflected light, and a pair of side surfaces 32 connected to the slope 31. It is installed so as to cover all directions. In the case of using a sample having a small diffusivity and a small spread of the light beam of the specular reflected light, the reflected light absorber 30 may be composed of only the plate-shaped slope 31 as shown in FIG. As long as the reflected light absorber 30 absorbs reflected light in all directions on the specular reflection side, its form can be appropriately changed regardless of the range of the reflection direction of the sample to be measured. Since the amount of light in a state where the reflected light absorber 30 is not installed is the amount of light due to general hemispherical reflection, the hemispherical reflectance can be obtained from the ratio with the reference amount of reflected light.

  By the way, when a sample 100 having a high diffusivity is used, retroreflected light toward the incident side and reflection in the specular reflection direction are mixed in the incident area where the incident light L is incident. Therefore, the reflected light in the specular reflection direction cannot be selectively absorbed. For example, in the example illustrated in FIGS. 5A and 5B, the incident area S includes an incident light side (retroreflection side) defined by the boundary surface P and a side opposite to the incident light (specular reflection side). Exists on both sides. Here, in FIGS. 5A and 5B, the reflected light to the incident side is indicated by a solid arrow, and the reflected light to the specular reflection side is indicated by a broken arrow.

  As shown in FIGS. 5A and 5B, at a point A which is an end on the specular reflection side of the incident area S, a part of the reflected light to be captured by the light receiving unit 40 toward the retroreflection side is reflected. The light is absorbed by the light absorber 30. On the other hand, at point B, which is the end of the incident area S on the retroreflective side, part of the reflected light to be absorbed by the reflected light absorber 30 toward the specular reflection side is integrated without being absorbed by the reflected light absorber 30. The light is directed toward the inner surface of the sphere 10 and is captured by the light receiving unit 40. Therefore, as a result, the excess or deficiency is offset. For example, when a completely diffusible sample is used as the sample 100, the amount of reflected light captured by the light receiving unit 40 is 50% of the amount of light captured by the light receiving unit 40 when the reflected light absorber 30 is not installed. It has been known.

  Here, in the optical measurement device 1, when the sample 100 has transparency, it is preferable to include a transmitted light absorber 50 as shown in FIG. The transmitted light absorber 50 is formed of a light absorbing film or the like, and is disposed at a position where the transmitted light transmitted through the sample 100 is incident. As shown in FIG. 6A, the transmitted light absorber 50 is provided on the surface of the sample 100 facing the sample surface 110 (the sample back surface 120), and is preferably arranged so as to be close to the sample back surface 120. . By providing the transmitted light absorber 50, transmitted light transmitted through the sample 100 can be absorbed. Accordingly, a measurement error caused by the transmitted light of the sample 100 being reflected, transmitting the sample 100 again, entering the integrating sphere 10, and being captured as reflected light by the light receiving unit 40 can be reduced.

  However, when the incident angle becomes high, the interface reflection (Fresnel reflection) of the transmitted light absorber 50 increases. As a result, as shown in FIG. 6A, a part of the transmitted light returns to the integrating sphere 10 without being absorbed, and can be detected as reflected light. FIG. 6B shows the spectra when the incident angle θ = 10 ° and the incident angle θ = 70 ° when incident light is directly incident on the transmitted light absorber 50 without using the sample 100. It is a figure showing the result of having measured reflectance. As shown in FIG. 6B, at an incident angle θ = 70 °, about 10% is reflected at each wavelength.

  Therefore, as shown in FIG. 7A, the transmitted light absorber 50 has an opening through which the transmitted light passing through the sample 100 is incident, and is a box-shaped transmitted light absorbing member formed of a box-shaped body that partitions the internal space R. It is preferably the body 51. As a result, the transmitted light that has entered the bottom surface of the box-shaped transmitted light absorber 51 at an incident angle of a predetermined value or more is reflected toward the side surface of the box-shaped transmitted light absorber 51 and is absorbed. The return of the transmitted light to the inside 10 can be reduced. FIG. 7B shows the case where the incident angle θ = 10 ° and the incident angle θ = 70 ° when the incident light is directly incident on the box-shaped transmitted light absorber 51 without using the sample 100. FIG. 6 is a diagram showing the result of measuring the spectral reflectance at. As is clear from FIG. 7B, the ratio of reflected light detected at an incident angle θ = 70 ° was reduced as compared with FIG. 6B.

  The light receiving unit 40 is installed at an arbitrary position inside the integrating sphere 10 so as to block light so that the incident light L and the reflected light from the sample 100 do not directly enter. The light receiving unit 40 is configured to include an optical member such as an optical fiber and an optical system such as a lens that collects reflected light on the optical member. The light captured by the light receiving unit 40 is detected by a spectroscope or the like provided outside the integrating sphere 10, and the intensity of, for example, ultraviolet light, visible light, infrared light, or the like in a wavelength range of 300 nm to 1650 nm is detected.

  Next, a method of measuring retroreflected light using the optical measurement device 1 will be described. Here, it is assumed that the optical measuring device 1 used in the present measuring method includes the box-shaped transmitted light absorber 51 described above.

  The reflected light absorber 30 and the box-shaped transmitted light absorber 51 included in the optical measuring device 1 respectively reflect the reflected light in all directions on the specular reflection side when the incident light L enters the sample 100 and the transmitted light of the sample 100. It is installed for the purpose of absorbing. However, as shown in FIG. 8, in the process where diffuse reflection and multiple reflection occur on the wall surface of the integrating sphere 10, a part of the light to be detected is absorbed by the reflected light absorber 30 and the box-shaped transmitted light absorber 51. Therefore, a measurement error may occur.

  The light amount loss that causes such a measurement error is measured as follows. First, as shown in FIG. 9A, only the standard reflector 200 is installed in the integrating sphere 10, and the incident light L is incident on the standard reflector 200 at an incident angle θ = 10 °, for example. The reflected light amount is used as a reference light amount. Similarly, with the incident light L incident on the standard reflector 200, the sample 100, the reflected light absorber 30, and the box-shaped transmitted light absorber 51 are arranged at adjacent positions as shown in FIG. 9B. The measured light amount is defined as a measured light amount. The absorption light amount is obtained by subtracting the measured light amount from the reference light amount, and the absorption light amount is divided by the reference light amount to obtain the absorption rate. From these results, the loss of the light amount due to the reflected light absorber 30 and the box-shaped transmitted light absorber 51 becomes apparent.

  Therefore, by setting the light amount in the state where the light amount loss occurs as the reference reflected light amount, the influence of the absorption by the reflected light absorber 30 and the box-shaped transmitted light absorber 51 can be excluded. If the reflectance of the standard reflector 200 does not match the reflectance of the inner wall of the integrating sphere 10, an error in the amount of light occurs in the process of diffuse reflection and multiple reflection in the integrating sphere 10 when measuring the standard reflector 200 as well. Therefore, the standard reflector 200, the sample 100, the reflected light absorber 30, and the box-shaped transmitted light absorber 51 are exchanged and arranged at the incident light irradiation position, and the reference reflected light amount and the measured light amount are measured. Can be corrected.

  It should be noted that the present invention is not limited only to the above-described embodiment, and various modifications or changes can be made.

  Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples.

  The components of the optical measuring device 1 used in the present embodiment are as follows. As the integrating sphere 10, an incident variable integrating sphere for reflection manufactured by Lambda Vision was used. A spectrometer and a spectrophotometer were used for light detection. Specifically, a spectrometer 1 (350 to 1100 nm) and a spectrometer 2 (950 to 1650 nm) manufactured by Lambda Vision Co., Ltd. are used as spectrometers, and a spectrophotometer (product of Hitachi High-Tech Science) is used as a spectrophotometer. Name: U4100) was used. As the reflected light absorber 30 and the box-shaped transmitted light absorber 51, an absorber manufactured by Acktar (trade name: Spectral Black) was used. A half mirror (trade name: PMH-25.4C03-10-4 / 20) manufactured by Sigma Koki Co., Ltd. was used as the half mirror. As the standard reflector 200, a standard reflector (trade name: Spectralon SRS-99-020) manufactured by Labsphere was used.

  The sample 100 used in this example is the following sample A and sample B. For sample A, a hot-wire recurring film (trade name: ALBEEDO, manufactured by Dexerials) and a float glass (50 mm × 40 mm × t3 mm) were bonded with an adhesive, and a hot wire formed such that the float glass surface became the sample surface. It is a recursive film-laminated glass (50 mm x 40 mm x t3.2 mm). As shown in FIG. 10, the heat ray recurring film included in the sample A includes an optical layer 151 having a smooth surface on which light is incident, and an uneven portion 152 having a substantially triangular cross-section and one-dimensionally arranged in the optical layer 151. And a reflective layer 153 formed on the shape surface of the uneven portion 152 and selectively reflecting infrared wavelengths. Sample B is float glass (50 mm × 40 mm × t3 mm).

[Correction of measurement error]
The above-described measurement error caused by the light to be detected being absorbed by the reflected light absorber 30 and the box-shaped transmitted light absorber 51 was corrected as follows.

  First, as shown in FIG. 9A, only the standard reflector 200 is installed in the integrating sphere 10 and the amount of reflected light when the incident light L is incident on the standard reflector 200 at an incident angle θ = 10 °. Was set as a reference light amount. Similarly, in a state where the incident light L is made incident on the standard reflector 200, as shown in FIG. 9B, the sample 100, the reflected light absorber 30, and the box-shaped transmitted light absorber 51 are placed adjacent to each other. The light amount measured with the arrangement was defined as the measured light amount. The absorption light amount was obtained by subtracting the measured light amount from the reference light amount, and the absorption amount was obtained by dividing the absorption light amount by the reference light amount. FIG. 11A shows the absorptance when only the box-shaped transmitted light absorber 51 is used as the absorber, and FIG. 11B shows the reflected light absorber 30 and the box-shaped transmitted light absorber as the absorber. The absorptivity when using No. 51 is shown. Here, when only the box-shaped transmitted light absorber 51 was used as the absorber, as shown in FIG. 11A, the measurement without the sample was performed in addition to the measurement of the sample A and the sample B. On the other hand, when the reflected light absorber 30 and the box-shaped transmitted light absorber 51 are used as the absorber, the measurement without the sample is performed because the reflected light absorber 30 is placed on the sample 100. , Samples A and B were measured. From these results, the loss of the light amount due to the absorber became clear, and it was found that even when the same absorber was used, the absorptance varied depending on the reflection characteristics of the sample.

  Therefore, the influence of absorption by the absorber can be excluded by setting the light amount in the state where the light amount loss occurs as the reference reflected light amount. If the reflectance of the standard reflector 200 does not match the reflectance of the inner wall of the integrating sphere 10, an error in the amount of light may occur in the process of diffuse reflection and multiple reflection in the integrating sphere 10 when measuring the standard reflector 200 as well. From the above, the standard reflector 200, the sample 100, the reflected light absorber 30, and the box-shaped transmitted light absorber 51 are replaced and arranged at the incident light irradiation position, and the reference reflected light amount and the measured light amount are measured. The error can be corrected.

  In the above-mentioned measurement method, the hemispherical reflectance of the sample A measured with the incident variable integrating sphere for reflection using only the box-shaped transmitted light absorber 51 and the hemisphere measured with a commercially available spectrophotometer (trade name: U4100) FIG. 12 shows the result of comparison with the reflectance. The angles of incidence on the samples were all θ = 10 ° and Φ = 10 °. Here, Φ is the azimuthal angle of the incident light L on the sample A when the angle perpendicular to the ridge line of the uneven portion 152 along the sample surface is set to 0 °. Although the measuring device and the measuring method were different, they agreed well.

[Measurement of incident-side omnidirectional reflectance]
For the measurement, the sample 100, the reflected light absorber 30, and the box-shaped transmitted light absorber 51 are installed inside, and the integrating sphere 10 having no opening other than the opening 11 into which the incident light L is incident. Was used. Then, as shown in FIGS. 13A and 13B, the reflectance is obtained by a measurement method in which the standard reflector 200 is replaced with the sample 100, the reflected light absorber 30, and the box-shaped transmitted light absorber 51. Was.

[Measurement Example 1]
The incident angle on the sample 100 was θ = 60 ° and Φ = 10 °. Thereby, since the reflected light on the incident side is incident on the inner wall of the integrating sphere 10, the dissipation of the reflected light from the opening 11 can be prevented. Here, the reason why the reflected light from the opening 11 can be prevented from dissipating under the above conditions will be described.

  As shown in FIGS. 14A and 14B, the sample A has an incident angle θ = 60 ° with respect to the sample surface, and an azimuth from a direction along the sample surface and perpendicular to the ridgeline of the uneven portion 152. At Φ = 0 °, only the infrared wavelength region is selectively retroreflected in the incident direction. Further, since the sample A has no diffusivity and the surface of the sample is formed as a substantially flat surface, when the azimuth angle Φ is changed while maintaining the incident angle θ = 60 °, the spread of light is small, and FIG. As shown in (1), the light is mainly divided into specular reflected light L1 on the float glass surface as the sample surface and reflected light L2 on the incident side with an azimuth angle of 2Φ. Therefore, under the above-mentioned conditions of θ = 60 ° and Φ = 0 °, most of the reflected light L2 to the incident side is retroreflected at the same angle as the incident light L, and is dissipated from the opening 11, so that A measurement error occurs. On the other hand, under the conditions of the present measurement example, θ = 60 ° and Φ = 10 °, the reflected light L2 to the incident side is incident on the inner wall of the integrating sphere 10, and thus does not dissipate from the opening 11. Therefore, the dissipation of the reflected light from the opening 11 can be prevented.

  Using Sample A, the hemispherical reflectance was measured depending on whether or not a half mirror was provided in the opening 11. FIG. 16 shows the results. As shown in FIG. 16, the difference in reflectance depending on the presence or absence of the half mirror was very small, and it was confirmed that there was no dissipation of reflected light.

  Next, using the sample A and the sample B, measurement was performed with and without the reflected light absorber 30, and the hemispherical reflectance and the incident-side omnidirectional reflectance were obtained. From the difference between the hemispherical reflectance and the omnidirectional reflectance on the incident side, the omnidirectional reflectance on the specular reflection side was calculated. FIG. 17 shows the result of Sample A, and FIG. 18 shows the result of Sample B.

  As shown in FIG. 17, it was confirmed that the incident-side omnidirectional reflectance of the sample A was very low in the visible region and high in the near-infrared region. This is because the optical layer 151, which is the reflection layer of the heat ray recurring film 150, is a selective reflection layer for infrared wavelengths, and the optical layer 151 is formed on an uneven surface whose reflection direction is on the incident side. It is considered that the reflected light on the incident side is limited to near-infrared light.

  On the other hand, as shown in FIG. 18, since the reflection of the sample B is only specular reflection at the air interface, the omnidirectional reflectance on the incident side is almost zero, and the omnidirectional reflectance on the specular reflection side is equal to the hemispherical reflectance. Become. Since the specular reflection side omnidirectional reflectance of the sample A is almost equal to that of the sample B, this is also considered to be a result of reproducing the above-described design characteristics.

[Measurement Example 2]
The incident angle on the sample was θ = 60 ° and Φ = 0 °. As a result, most of the reflected light on the incident side is retroreflected at the same angle as the incident light L as described above, and is thus scattered from the opening 11.

  Using the sample A, the measurement of the hemispherical reflectance in the case where the half mirror was installed in the opening 11 and the case where the half mirror was not installed were respectively performed. The results are shown in FIG. As shown in FIG. 19, regardless of the presence or absence of the half mirror, due to the loss of the amount of dissipated light, it is detected more than the reflectance under the incident condition of θ = 60 ° and φ = 10 ° without the dissipated light. It was confirmed that the reflectance decreased.

  Next, based on the hemispherical reflectance depending on the presence or absence of the half mirror and the reflectance of the half mirror shown in FIG. 20, the dissipated light compensation reflectance is calculated from a relational expression (dissipated light compensation reflectance = Rn + (Rh−Rn) / ρh). I asked. Here, the measured reflectance when the half mirror is installed is Rh, the measured reflectance when the half mirror is not installed is Rn, and the reflectance of the half mirror is ρh. In this relational expression, since the difference (Rh−Rn) between the reflectances with and without the half mirror corresponds to the amount of light reflected into the integrating sphere by the half mirror, this is divided by the reflectance (ρh) of the half mirror. The amount of reflected light from the sample that has entered the half mirror can be determined. Since the reflected light to the half mirror is the dissipated light from the opening 11, the sum of the reflected light and the reflectance Rn when the half mirror is not installed is calculated to obtain the total reflected light amount including the dissipated light. The reflectance can be determined.

  As shown in FIG. 21, it was confirmed that the above-described scattered light-compensated reflectance almost completely coincided with the reflectance measured without measurement of the scattered light, and was the same as the incident angle of the incident light L. It has been found that the retroreflected light at the reflection angle can be measured.

  According to the present invention, it is possible to measure the reflectance in a desired angle range.

REFERENCE SIGNS LIST 1 optical measuring device 10 integrating sphere 11 opening 20 sample table 30 reflected light absorber 31 slope 32 side surface 40 light receiving unit 50 transmitted light absorber 51 box-shaped transmitted light absorber 100 sample 110 sample surface 120 sample back surface 150 heat ray recurring film 151 Optical layer 152 Concavo-convex portion 153 Reflective layer 160 Float glass 200 Standard reflector L Incident light L1 Specular reflected light L2 Reflected light O to incident side O Normal line P Boundary surface R Internal space S Incident area

Claims (6)

An integrating sphere having an opening, and receiving incident light from an external light source through the opening;
Among the planes including the normal line at the position where the incident light is incident on the sample whose surface is disposed exposed in the integrating sphere, any plane other than the incident plane including the incident light and the specular reflected light Through a certain boundary surface, a reflected light absorber installed to absorb omnidirectional reflected light opposite to the incident light,
Optical measuring device.   The optical measurement device according to claim 1, further comprising a detachable half mirror that covers the entirety of the opening.   The optical measurement device according to claim 1, further comprising a transmitted light absorber installed on a back surface side of the sample and absorbing transmitted light transmitted through the sample.   The optical measurement device according to claim 3, wherein the transmitted light absorber is a box-shaped body having an opening through which the transmitted light transmitted through the sample is incident. A measurement method using the optical measurement device according to any one of claims 1 to 4,
Arranging the sample at a position where the incident light does not enter in the integrating sphere, and arranging a standard reflector at a position where the incident light enters, to obtain a reference reflected light amount,
Replacing the sample and the standard reflector to obtain an incident-side omnidirectional reflected light amount;
Based on the reference reflected light amount and the incident-side omnidirectional reflected light amount, obtaining the incident-side omnidirectional reflectance,
Measurement method including: A measurement method using the optical measurement device according to claim 2,
Assuming that the reflectance of the half mirror is ρh, the measured reflectance when the half mirror is installed is Rh, and the measured reflectance when the half mirror is not installed is Rn, the retroreflection dissipated from the opening to the outside of the integrating sphere. The light-compensated diffused light compensation reflectance is
Formula: Rn + (Rh−Rn) / ρh
Measurement method obtained by

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