JP3144798U - Absolute reflection measuring device - Google Patents

Abstract

An absolute reflection measuring apparatus capable of measuring even with a small incident angle and a small incident angle is provided.
A light source 11, an optical system 12 that emits a light beam emitted from the light source 11 as a measurement light beam 12A, and a sample S that is rotatably mounted to the measurement light beam 12A and the reflected light 10A is mirrored. 14 has a structure composed of an integrating sphere 13a introduced through 14 and movably supported, a photoelectric converter 13b disposed in the integrating sphere 13a, and the like. The mirror 14 is composed of a concave mirror supported by a support base 16 that holds a detector 13 composed of an integrating sphere 13a and a photoelectric converter 13b, and is formed between the reflecting surface of the sample S and the center of the measurement light beam 12A. A predetermined range on the circumference around the intersection can be moved. Even if the angle θ1 of the mirror 14 varies with respect to the reflected light 10A, the mirror 14 is a concave mirror, the variation in incident angle is reduced, and the variation in specular reflectance is small.
[Selection] Figure 1

Description

  The present invention relates to a variable angle absolute reflection measuring apparatus that can measure an error even when an incident angle is small, and more particularly to a structure in which a reflected light beam is incident on a detector.

  In the absolute reflection measuring apparatus, a measurement light beam emitted from an optical system composed of, for example, a spectroscope in the absence of a sample is directly incident on a detector composed of, for example, an integrating sphere and a photoelectric converter, and a measured signal is predetermined. After setting the sensitivity of the measurement system so that it has a constant magnitude (100%) over the wavelength range of, the measurement light beam dispersed by the spectroscope is incident on the sample, and the light beam reflected at the same angle as the incident angle The absolute reflectance is defined as the magnitude (%) of a signal that is incident on the detector and is measured in a measurement system under the same sensitivity condition as the previous time over a predetermined wavelength range. Thus, absolute reflection measurement is a measurement method that does not use a reference sample.

  In the reflection measurement, when the incident angle is large, the reflectances of the vibration component perpendicular to the incident surface (s-polarized light) and the vibration component parallel to the incident surface (p-polarized light) are different. For this reason, when performing absolute reflection measurement at a large incident angle, the incident light is set to either s-polarized light or p-polarized light using a polarizer, and each is measured separately.

  As shown in FIG. 5, a conventional absolute reflection measuring apparatus includes a light source 51, an optical system 52 that emits a light beam emitted from the light source 51 as a measurement light beam 52A, and a sample on which the measurement light beam 52A is rotatably mounted. S is configured to include an integrating sphere 53a that is movably supported by which reflected light 50A having a reflection angle θ is introduced by irradiation with an incident angle θ, and a photoelectric converter 53b disposed in the integrating sphere 53a. The detector 53 includes an integrating sphere 53a and a photoelectric converter 53b.

  In the measurement of the absolute reflectance, the measurement light beam 52A emitted from the optical system 52 without the sample S is directly incident on the detector 53 (moved to the position indicated by the broken line) so that the measured signal becomes 100%. After setting the sensitivity of the measurement system, the measurement light beam 52A is incident on the sample S at the incident angle θ, and the reflected light detection system angle is set so that the reflected light 50A having the reflection angle θ is incident on the detector 53. Obtain the magnitude (%) of the signal measured by the measurement system under the same sensitivity condition. The integrating sphere 53a moves toward the intersection of the reflection surface of the sample S and the center of the measurement light beam 52A with the opening thereof on the circumference centering on the intersection according to the incident angle θ. Therefore, when the incident angle θ is small, the measurement light beam 52A is blocked by the integrating sphere 53a, making measurement difficult.

  In order to solve the problem of difficulty in measurement when the incident angle θ is small, the following two mirrors are arranged in the absolute reflection measuring apparatus shown in FIG. 5 (see, for example, Patent Document 1). That is, in FIG. 6, the first fixed mirror 64 that reflects the measurement light beam 52A from the optical system 52, and the measurement light beam 52A reflected by the first fixed mirror 64 is reflected toward the rotation center of the sample S. Two fixed mirrors 65 are provided. The first and second fixed mirrors 64 and 65 are disposed inside the movement locus of the detector 53, and the first fixed mirror 64 reflects the measurement light beam 52A in an acute angle direction. In FIG. 6, parts denoted by the same reference numerals as those in FIG. 5 are the same as those in FIG.

  As another method for solving the problem of difficulty in measurement when the incident angle θ is small, one mirror described below may be provided in the absolute reflection measuring apparatus shown in FIG. That is, instead of causing the reflected light 50A to directly enter the detector 53, as shown in FIG. 7, the reflected light 50A is incident on the mirror 74 held on the movable frame on which the detector 53 is supported, and the opening is changed by 90 °. It is introduced into the detector 53 directed in the direction of the mirror 74. In FIG. 7, the parts denoted by the same reference numerals as those in FIG. 5 are the same as those in FIG.

The mirror used is usually a mirror-deposited glass surface deposited with Al. The specular reflectance characteristics of the Al vapor deposition mirror vary depending on the incident angle of the light beam. FIG. 4 is a diagram showing the relationship between the incident angle of a light beam having a wavelength of, for example, 500 nm and the specular reflectivity. (RE) s shows the specular reflectivity characteristic of s-polarized light and (RE) p shows the specular reflectivity characteristic of p-polarized light.
JP 2004-198244 A

  As described above, the problem that measurement is difficult when the incident angle / reflection angle is small has been improved. However, when a single mirror is provided and the reflected light 50 </ b> A is turned 90 ° and introduced into the detector 53, the mirror is used. The incident angle is about 45 °. As shown in FIG. 4, when the incident angle is less than 10 °, the mirror reflectivity of the mirror does not change even if the incident angle fluctuates. However, near the incident angle of 45 °, an error in the incident angle causes a change in the specular reflectivity. Measurement error of absolute reflectance. Therefore, if there is an error in the detector setting angle, an error occurs in the incident angle to the mirror, resulting in an absolute reflectance measurement error.

  The present invention provides a light source, an optical system that emits a light beam emitted from the light source as a measurement light beam, and a detector in which the measurement light beam is irradiated onto a rotatably mounted sample and the reflected light is introduced through a mirror. In the absolute reflection measuring apparatus, the mirror is configured by a concave mirror supported by a support base that holds the detector, and the support base is centered on the intersection of the reflection surface of the sample and the center of the measurement light beam. A predetermined range on the circumference can be moved. Therefore, even if the angle of the mirror varies with respect to the reflected light from the sample, the variation in the incident angle is reduced.

  Alternatively, it has a light source, an optical system that emits a light beam emitted from the light source as a measurement light beam, and a detector that irradiates the measurement light beam to a rotatably mounted sample and introduces the reflected light through a mirror. In the absolute reflection measuring apparatus, the mirror is composed of a plane mirror supported by a support table that holds the detector, and the support table has a circumference centered at the intersection of the reflection surface of the sample and the center of the measurement light beam. The distance between the reflected light introducing hole of the detector and the mirror is longer than the distance between the sample and the mirror, and the incident angle of the reflected light from the sample to the mirror is 10 ° or less.

  An absolute light source, an optical system that emits a light beam emitted from the light source as a measurement light beam, and a detector that irradiates the measurement light beam to a rotatably mounted sample and introduces the reflected light through a mirror. In the reflection measurement apparatus, the mirror is composed of two or more plane mirrors and is supported by a support base that holds the detector, and the support base is centered on the intersection of the reflection surface of the sample and the center of the measurement light beam. The angle of incidence of the reflected light from the sample on the mirror is 10 ° or less. Therefore, even if the angle of the mirror fluctuates with respect to the reflected light from the sample and the incident angle changes, the fluctuation in the mirror reflectivity of the mirror is small.

  When the reflected light from the sample is introduced into the detector through the concave mirror, even if the angle of the concave mirror varies with respect to the reflected light due to a setting error of the reflected light detection system angle, the variation in the incident angle is reduced and the concave mirror There is little fluctuation in specular reflectance, and the measurement error of absolute reflectance is small. When the reflected light is introduced into the detector through a mirror disposed so that the incident angle with respect to the reflected light from the sample is 10 ° or less, the reflected light is detected due to a setting error of the reflected light detection system angle. Even if the angle of the mirror fluctuates and the incident angle changes, the specular reflectance variation of the mirror is small and the absolute reflectance measurement error is small. In addition, when the incident angle is 10 ° or less, the change in the specular reflectance with respect to the variation in the incident angle is small for the polarization component, and the measurement error is small even in the measurement of the absolute reflectance such that the polarizer is placed on the back side of the sample. .

  Each mirror has a structure in which Al is vapor-deposited on the polished surface of the glass, and when changing the incident angle to be measured, the detector moves along the circumference around the intersection of the reflecting surface of the sample and the center of the measuring beam with the detector. The angle is set at an angle at which the reflected light with the same reflection angle is incident on the detector, and the reflected light detection system angle is set.

  An embodiment of claim 1 of the present invention will be described with reference to FIG. FIG. 1 is a diagram showing a schematic structure of an absolute reflection measuring apparatus according to Embodiment 1 of the present invention. As shown in FIG. 1, the absolute reflection measuring apparatus according to Embodiment 1 of the present invention splits a light source 11 composed of, for example, a halogen lamp and a white light beam emitted from the light source 11 and emits it as a measurement light beam 12A of monochromatic light. An optical system 12 composed of a spectroscope and an integrating sphere 13a supported so as to be movable, in which the measurement light beam 12A is irradiated onto the sample S mounted rotatably and the reflected light 10A is introduced through a mirror 14. And a photoelectric converter 13b composed of, for example, a photomultiplier arranged in the integrating sphere 13a. The mirror 14 is composed of a concave mirror supported by a support base 16 that holds a detector 13 composed of an integrating sphere 13a and a photoelectric converter 13b, and is formed between the reflecting surface of the sample S and the center of the measurement light beam 12A. A predetermined range on the circumference around the intersection can be moved.

  Since the first embodiment of the present invention has the above structure, even if the angle θ1 of the mirror 14 formed of a concave mirror with respect to the reflected light 10A varies due to a setting error of the reflected light detection system angle, the incident angle varies. Is reduced, and the variation in the specular reflectance of the mirror 14 is small and the absolute reflectance measurement error is small. For example, when the radius of curvature of the mirror 14 is √2 times the distance between the mirror 14 and the sample S, even if the angle of the mirror 14 varies by 1 ° with respect to the reflected light 10A, the variation of the incident angle is about 0.01 °. is there.

  The absolute reflectance is measured as follows. The measurement light beam 12A emitted from the optical system 12 without the sample S is directly incident on the detector 13 (moved to the position indicated by the broken line) via the mirror 14 so that the measured signal becomes 100%. After setting the sensitivity of the measurement system every time, the measurement light beam 12A is incident on the sample S at the incident angle θ, and the reflected light 10A having the reflection angle θ is incident on the detector 13 via the mirror 14. The angle is set, and the magnitude (%) of the signal of each wavelength measured by the measurement system under the same sensitivity condition as the previous time is obtained. In the absolute reflection measuring apparatus according to the first embodiment of the present invention, when the incident angle θ is small as shown in FIG. 1, the measurement can be performed until the measurement light beam 12A is blocked by the mirror 14, and even if the incident angle θ is small, integration is possible. The measurement light beam 12A is not blocked by the sphere 13a.

  In the first embodiment shown in FIG. 1, the detector 13 has a structure composed of an integrating sphere 13a and a photoelectric converter 13b. However, the present invention can be applied even if the detector 13 is replaced with a coolant / support for the photoelectric converter 13b instead of the integrating sphere 13a. Is applicable. In addition, although the illustrated example has a single beam configuration, the present invention can also be applied to a double beam configuration in which the measurement light beam 12A is branched by a half mirror and the branched light beam is introduced into a detector for monitoring. Includes these variations.

  An embodiment of claim 2 of the present invention will be described with reference to FIG. FIG. 2 is a diagram showing a schematic structure of an absolute reflection measuring apparatus according to Embodiment 2 of the present invention. As shown in FIG. 2, the absolute reflection measuring apparatus according to Embodiment 2 of the present invention splits a light source 21 composed of, for example, a halogen lamp and a white light beam emitted from the light source 21, and emits it as a measurement light beam 22A of monochromatic light. An optical system 22 composed of a spectroscope and an integrating sphere 23a supported so as to be movable, in which the measurement light beam 22A is irradiated onto a rotatably mounted sample S and the reflected light 20A is introduced through a mirror 24. And a photoelectric converter 23b composed of, for example, a photomultiplier arranged in the integrating sphere 23a. The mirror 24 is composed of a plane mirror supported by a support base (not shown) that holds a detector 23 composed of an integrating sphere 23a and a photoelectric converter 23b, and reflects the reflection surface of the sample S and the measurement light beam 22A. A predetermined range on the circumference centering on the intersection with the center can be moved, and the distance between the detector 23 and the mirror 24 is longer than the distance between the sample S and the mirror 24. The reflected light 20A enters the mirror 24 at an incident angle θ2, and the incident angle θ2 is set to 10 ° or less. A shielding plate 27 is disposed in the vicinity of the opening of the integrating sphere 23a to block the incident light of the scattered light of the sample S from entering the opening.

  Since the second embodiment of the present invention has the above-described structure, even if the incident angle θ2 of the reflected light 20A to the mirror 24 constituted by the plane mirror varies due to a setting error of the reflected light detection system angle or the like, it is 10 ° or less. Since it is set, the variation in the specular reflectance of the mirror 24 is small, and the measurement error of the absolute reflectance is small. Further, since each component can be arranged in the vicinity of the sample S, a small absolute reflection measuring device can be provided.

  The absolute reflectance is measured as follows. The measurement light beam 22A emitted from the optical system 22 in the absence of the sample S is directly incident on the detector 23 (moved to the position indicated by the broken line) via the mirror 24 so that the measured signal becomes 100%. After setting the sensitivity of the measurement system every time, the measurement light beam 22A is incident on the sample S at the incident angle θ, and the reflected light 20A having the reflection angle θ is incident on the detector 23 via the mirror 24. The angle is set, and the magnitude (%) of the signal of each wavelength measured by the measurement system under the same sensitivity condition as the previous time is obtained. In the absolute reflection measuring apparatus according to the second embodiment of the present invention, when the incident angle θ is small as shown in FIG. 2, the measurement can be performed until the measurement light beam 22A is blocked by the mirror 24, and integration is performed even when the incident angle θ is small. The measurement light beam 22A is not blocked by the sphere 23a.

  An embodiment of claim 3 of the present invention will be described with reference to FIG. FIG. 3 is a diagram showing a schematic structure of an absolute reflection measuring apparatus according to Embodiment 3 of the present invention. As shown in FIG. 3, the absolute reflection measuring apparatus according to the third embodiment of the present invention splits a light source 31 composed of, for example, a halogen lamp and a white light beam emitted from the light source 31 and emits it as a measurement light beam 32A of monochromatic light. An optical system 32 composed of a spectroscope, and a measurement light beam 32A that is irradiated on a sample S that is rotatably mounted and its reflected light 30A is introduced through mirrors 34 and 35 so as to be supported in a movable manner. It has a structure composed of a sphere 33a and a photoelectric converter 33b, for example, composed of a photomultiplier tube disposed in the integrating sphere 33a. The mirrors 34 and 35 are constituted by plane mirrors supported by a support base (not shown) that holds a detector 33 constituted by an integrating sphere 33a and a photoelectric converter 33b. A predetermined range on the circumference around the intersection with the center of 32A can be moved. The reflected light 30A is incident on the mirror 34 at an incident angle θ3, and is reflected by the mirror 34 and incident on the mirror 35 at an incident angle θ4. The incident angles θ3 and 4 are set to 10 ° or less.

  Since the third embodiment of the present invention has the above-described structure, even if the incident angles θ3 and 4 of the reflected light 30A to the mirrors 34 and 35 formed by the plane mirrors fluctuate due to a setting error of the reflected light detection system angle or the like. Since the angle is set to 10 ° or less, there is little variation in the specular reflectance of the mirrors 34 and 35, and the measurement error of the absolute reflectance is small.

  The absolute reflectance is measured as follows. The measurement light beam 32A emitted from the optical system 32 without the sample S is directly incident on the detector 33 (moved to the position indicated by the broken line) via the mirrors 34 and 35 so that the measured signal becomes 100%. After setting the sensitivity of the measurement system for each wavelength, the measurement light beam 32A is incident on the sample S at the incident angle θ, and the reflected light 30A having the reflection angle θ is incident on the detector 33 via the mirrors 34 and 35. The reflected light detection system angle is set, and the magnitude (%) of the signal of each wavelength measured by the measurement system under the same sensitivity condition as the previous time is obtained. In the absolute reflection measuring apparatus according to the third embodiment of the present invention, when the incident angle θ is small as shown in FIG. 3, measurement is possible until the measurement light beam 32A is blocked by the mirror 34, and integration is performed even when the incident angle θ is small. The configuration is such that the measurement light beam 32A is not blocked by the sphere 33a.

  The present invention can be used for an angle variable absolute reflection measuring apparatus that can measure with little error even when the incident angle is small.

It is a figure which shows schematic structure of the absolute reflection measuring apparatus by Example 1 of this invention. It is a figure which shows schematic structure of the absolute reflection measuring apparatus by Example 2 of this invention. It is a figure which shows schematic structure of the absolute reflection measuring apparatus by Example 3 of this invention. It is a figure which shows the relationship between the incident angle of Al vapor deposition mirror, and a specular reflectance. It is a figure which shows schematic structure of the conventional absolute reflection measuring apparatus. It is a figure which shows schematic structure of the conventional absolute reflection measuring apparatus. It is a figure which shows schematic structure of the conventional absolute reflection measuring apparatus.

Explanation of symbols

10A reflected light 11 light source 12 optical system 12A measurement light beam 13 detector 13a integrating sphere 13b photoelectric converter 14 mirror 16 support base 20A reflected light 21 light source 22 optical system 22A measurement light beam 23 detector 23a integrating sphere 23b photoelectric converter 24 mirror 27 Shielding plate 30A Reflected light 31 Light source 32 Optical system 32A Measuring light beam 33 Detector 33a Integrating sphere 33b Photoelectric converter 34 Mirror 35 Mirror 50A Reflected light 51 Light source 52 Optical system 52A Measuring light beam 53 Detector 53a Integrating sphere 53b Photoelectric converter 64 Fixed Mirror 65 Fixed mirror 74 Mirror S Sample

Claims (3)

  An absolute light source, an optical system that emits a light beam emitted from the light source as a measurement light beam, and a detector that irradiates the measurement light beam to a rotatably mounted sample and introduces the reflected light through a mirror. In the reflection measuring apparatus, the mirror is composed of a concave mirror supported by a support table that holds the detector, and the support table is on a circumference centered at an intersection of the reflection surface of the sample and the center of the measurement light beam. An absolute reflection measuring apparatus capable of moving within a predetermined range.   An absolute light source, an optical system that emits a light beam emitted from the light source as a measurement light beam, and a detector that irradiates the measurement light beam to a rotatably mounted sample and introduces the reflected light through a mirror. In the reflection measuring apparatus, the mirror is composed of a plane mirror supported by a support base that holds the detector, and the support base is on a circumference centered at an intersection of the reflection surface of the sample and the center of the measurement light beam. The distance between the reflected light introduction hole of the detector and the mirror is longer than the distance between the sample and the mirror, and the incident angle of the reflected light from the sample to the mirror is 10 °. An absolute reflection measuring apparatus characterized by the following.   An absolute light source, an optical system that emits a light beam emitted from the light source as a measurement light beam, and a detector that irradiates the measurement light beam to a rotatably mounted sample and introduces the reflected light through a mirror. In the reflection measurement apparatus, the mirror is composed of two or more plane mirrors and is supported by a support base that holds the detector, and the support base is centered on the intersection of the reflection surface of the sample and the center of the measurement light beam. An absolute reflection measuring apparatus, which is movable within a predetermined range on the circumference of the circle, and the incident angle of the reflected light from the sample to the mirror is 10 ° or less.

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