JP3688513B2 - Reflection spectrum measuring device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention, spectral analysis of the sample relates to the reflection spectrum measurement TeiSo location used for the surface measurement or the like, in particular, those ruins relates to an apparatus for non-destructively measuring the precious sample such as archaeological heritage.
[0002]
[Prior art]
In general, in spectroscopic reflection measurement, specular reflection light and diffuse reflection light are mixed in more or less depending on the roughness and smoothness of the surface of the sample. That is, there is a problem that the spectrum of the differential shape is mixed with the spectrum of the diffuse reflection light at an arbitrary ratio due to the influence of the specular reflection light, and the shape of the obtained spectrum is distorted. That is, the surface roughness of the object to be measured, the measured value itself is dominated contained elements would increase the error. Therefore, conventionally, a method has been adopted in which the surface of a sample is processed to measure diffusely reflected light.
[0003]
[Problems to be solved by the invention]
As described above, when the surface of the sample is processed to measure diffusely reflected light, it is necessary to process the surface of the sample, so that there is a problem that nondestructive measurement cannot be performed. there were.
[0004]
The present invention is to eliminate the above problems, without performing processing of the surface of the sample, and an object thereof is to provide a reflection spectrum measurement TeiSo location that can perform non-destructive measurements.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides
[ 1 ] In the reflection spectrum measuring apparatus, an ellipsoidal mirror, a light source, a sample arranged in the ellipsoidal mirror, a photodetector arranged in the ellipsoidal mirror, and a computer connected to the photodetector The sample is disposed at one focal point of the ellipsoidal mirror, the photodetector is disposed at the other focal point of the ellipsoidal mirror, and the incident angle of light incident on the sample is variable. And a drive mechanism for performing the above operation.
[0006]
[ 2 ] In the reflection spectrum measuring apparatus according to [ 1 ], a light source is fixed to the ellipsoidal mirror, and the ellipsoidal mirror can be driven by a rotation driving mechanism.
[0007]
[ 3 ] The reflection spectrum measuring apparatus according to the above [ 1 ], further comprising a stage and an adjusting device that make the detection angle of the photodetector variable.
[0008]
[ 4 ] The reflection spectrum measuring apparatus according to [ 1 ], wherein a groove is formed in the ellipsoidal mirror, and the light source is movably disposed.
[0009]
[ 5 ] In the reflection spectrum measuring apparatus according to [ 1 ], the inner surface of the elliptical mirror is a metal-plated mirror.
[0010]
[ 6 ] The reflection spectrum measuring apparatus according to the above [ 1 ], wherein an opening that allows light from a light source to pass is provided in a part of the elliptical mirror.
[0011]
[ 7 ] In the reflection spectrum measuring apparatus described in [ 1 ] above, only the light reflected from the same sample surface is detected by applying a mask to the sample.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail.
[0013]
FIG. 1 is a schematic diagram of a reflection spectrum measuring apparatus showing a first embodiment of the present invention, and FIG. 2 is a schematic diagram showing an incident state of infrared light on a sample of the reflection spectrum measuring apparatus.
[0014]
In this figure, 1 is a spheroidal mirror, 2 is an infrared light source that emits infrared light fixed to the spheroidal mirror 1, 3 is a sample disposed at the focal position of the spheroidal mirror 1, 4 Is a photodetector arranged at the focal position of the spheroid mirror 1, 5 is a rotation drive mechanism of the spheroid mirror 1, 6 is a computer connected to the photodetector 4, 7 is a stage equipped with a photodetector, 8 Is a device for adjusting the photodetector-mounted stage.
[0015]
As shown in this figure, the sample 3 and the photodetector 4 are arranged at the respective focal positions of the spheroid mirror 1, and the rotation drive mechanism 5 of the spheroid mirror 1 (for example, micro-drive by a piezoelectric element). By driving the mechanism), the position of the infrared light source 2 is moved, and the incident angle to the set sample 3 can be made variable.
[0016]
Further, an accurate light detection angle can be obtained by adjusting the detection angle of the light detector 4 by the adjusting device 8 of the light detector mounting stage 7.
[0017]
As described above, according to the present invention, the diffuse reflection component can be continuously changed by measuring the incident angle to the sample 3 and the light detection angle to the photodetector to be variable, which is compact and high. A quality reflection spectrum measuring device can be constructed.
[0018]
Further, by using the spheroid mirror 1 and placing the sample 3 at one focal position and the photodetector 4 at the other focal position, the light collection rate can be maximized.
[0019]
In addition to this, by using, for example, a gold-plated mirror as the inner surface of the spheroid mirror 1, it is possible to estimate the diffuse reflection component spectrum with higher quality by reducing the spectrum background. Further, Al plating may be used instead of gold plating.
[0020]
Hereinafter, a method for measuring the reflection spectrum of the sample will be described with reference to the flowchart in FIG. 3 and the spectrum diagrams in each measurement process from FIG. 4 to FIG. 4 through 11, the horizontal axis is obtained by dividing the 1869-point to 3600 cm ^-1 wavenumber 4000cm ^-1 ~400cm ^-1 approximately every 2 cm ^-1. 4, 7, 9, 10, and 11, the vertical axis represents absorbance, the horizontal axis represents wave number, and in FIGS. 5, 6, and 8, the vertical axis represents the integrated value of absorbance (arbitrary unit). ), The horizontal axis indicates the wave number.
[0021]
(1) First, a polystyrene plate as a sample is fixed, and infrared light is incident on the surface of the polystyrene plate while changing the incident angle . Ri by the penetration depth of the thus incident light ging Rukoto to measure a series of spectra by changing the proportion of diffused light (step S1). The state is shown in FIG. That is, a series of spectra with slightly different component ratios on the diffuse mirror surface are measured.
[0022]
(2) Next, integration processing of the series of spectra is performed (step S2). An example of this state is shown in FIG. That is, the result of integral conversion of the reflection spectrum can be obtained. The integration process is performed by a computer (measuring device) 6. The integration process can also be performed by integrating a plurality of times.
[0023]
(3) Next, it is determined whether it is absorption spectrum candidate data A or specular reflection spectrum candidate data B (step S3). The discrimination process is performed by a computer (measuring device) 6.
[0024]
(4) Next, when it is determined as absorption spectrum candidate data A in step S3, the absorption spectrum candidate data A is separated from a plurality of data obtained by integrating the reflection spectrum (step S4). An example is shown in FIG. This separation process is also performed by the computer (measuring device) 6.
[0025]
(5) Next, differential processing of the absorption spectrum candidate data A obtained in step S4 is performed (step S5). An example of this state is shown in FIG. That is, a so-called absorption spectrum can be obtained from the reflection spectrum. This differentiation process is also performed by the computer (measuring device) 6.
[0026]
(6) When it is discriminated as specular reflection spectrum candidate data B in step S3, specular reflection spectrum candidate data B is separated from a plurality of data obtained by integrating the reflection spectrum (step S6). An example is shown in FIG . Separation process This is also performed by a computer (measuring apparatus) 6. The separation algorithm is MCR (Multi Curve Resolution: Touler et. Al Amal. Chem. 1994, 66, 3337) or SCA (Specific Component Analysis: Kawata et. Al J. Opt. Soc. However, since the algorithm itself is not a feature of the present invention, description thereof is omitted.
[0027]
(7) Next, the specular reflection spectrum candidate data B obtained in step S6 is differentiated (step S7). An example of this state is shown in FIG. That is, a specular reflection spectrum of the reflection spectrum can be obtained. This differentiation process is also performed by the computer (measuring device) 6. This differentiation process is performed the same number of times as the number of integrations.
[0028]
In addition, although the integration process and the differentiation process are performed as the data processing method, the present invention is not limited to this, and non-negative conversion is sufficient.
[0029]
For non-negative conversion, there are the following methods.
[0030]
1. Add a constant constant over the whole region of the spectrum.
[0031]
2. The absolute value is taken over the entire region of the spectrum.
[0032]
3. Integrate over the entire region of the spectrum.
[0033]
4). After integration over the entire region of the spectrum, a certain constant is added (the minimum value is 0 or more).
[0034]
Here, a graph of the three-time integration of the spectrum is shown in FIG. As one of the four methods, there is also a method of subtracting the minimum integration curve a from the other integration curves and separating the components among the three integrations and then differentiating them three times. This method has the advantage that the linearity of the spectrum can be confirmed.
[0035]
FIG. 11 is a diagram showing a true absorption spectrum of a film prepared by dissolving a polystyrene plate and an estimated absorption spectrum obtained by the present invention. Note that the curve b is actually at the same level as the curve a, but overlaps, so the curve b is displayed shifted upward.
[0036]
As can be seen from FIG. 11, the estimated absorption spectrum a of the present invention has a relative ratio of peak intensities slightly different from the true absorption spectrum b, but the peak positions are the same, there is no negative peak, and qualitative measurement. The result that can endure is obtained.
[0037]
In the above embodiment, the case where the position of the light source is variable has been described. However, the light source may be fixed and the position of the sample may be variable.
[0038]
FIG. 12 is a schematic diagram of a reflection spectrum measuring apparatus showing a second embodiment of the present invention.
[0039]
In addition, the same code | symbol is attached | subjected to the part of the same structure as above-mentioned 1st Example, and those description is abbreviate | omitted.
[0040]
In this figure, 10 is a fixed ellipsoidal mirror, 10A is an opening formed in the ellipsoidal mirror, 11 is a fixed light source, and the light source 11 is composed of a light source body 12 and a reflecting mirror 13. Reference numeral 14 denotes a sample stage that makes the position of the sample 3 variable, and reference numeral 15 denotes a sample position setting device that drives the sample stage 14 to set the position of the sample.
[0041]
In this embodiment, the light from the fixed light source 11 is irradiated to the sample 3 whose position can be set variably, and the reflection is measured. That is, the stage 14 of the sample 3 is set by the sample position setting device 15, and the position of the sample 3 can be set variably.
[0042]
13 is a block diagram of a reflection spectrum measuring apparatus (part 1) showing a third embodiment of the present invention. FIG. 13 (a) is a plan view of the reflection spectrum measuring apparatus, and FIG. 13 (b) is its reflection spectrum. It is an elevation view of a measuring device.
[0043]
In this embodiment, the light source of the second embodiment is movable in the major axis direction of the ellipsoidal mirror 10. That is, by forming a groove (opening) 21 in the axial direction of the fixed ellipsoidal mirror 10, the light source by driving dynamic (not shown) can be the incident angle of the incident light to the sample (not shown) variable It is configured as follows. Reference numerals 22 and 23 denote the focal points of the ellipsoidal mirror 10.
[0044]
FIG. 14 is a configuration diagram of a reflection spectrum measuring apparatus (part 2) showing a third embodiment of the present invention, FIG. 14 (a) is a plan view of the reflection spectrum measuring apparatus, and FIG. 14 (b) is its reflection spectrum. It is an elevation view of a measuring device.
[0045]
In this embodiment, the light source of the second embodiment described above is configured to be movable in the substantially short axis direction of the ellipsoidal mirror 10. That is, a groove (opening) 24 is formed in a substantially short axis direction of the fixed ellipsoidal mirror 10, and a light source (not shown) is driven to make an incident angle of incident light on a sample (not shown) variable. It is configured as follows. Reference numerals 22 and 23 denote the focal points of the ellipsoidal mirror 10.
[0046]
Further, it goes without saying that both the light source and the sample are movable.
[0047]
Alternatively, both the light source and the sample may be fixed, and an optical system such as a reflecting mirror and a lens may be moved to change the incident angle of light incident on the sample.
[0048]
Furthermore, in the above-described embodiment, when the incident angle of the incident light beam is changed during measurement of the sample surface, the irradiation area changes. Therefore, it is desirable to put a mask on the sample to avoid this.
[0049]
For example, when the incident angle of the incident light beam is changed from FIG. 15A to FIG. 15B, the absorption spectrum of the irradiation area S ₁ is included in the case of the incident light beam 31 in FIG. 15A. On the other hand, in the case of FIG. 15B, even with the same incident light beam 31 as in FIG. 15A, the absorption spectrum (diffuse reflection) of the irradiation area S ₂ wider than the irradiation area S _1. Will be included.
[0050]
Here, a mask 42 is provided on the sample surface 41 as shown in FIG . The mask 42, since it is desirable to absorb all the incident light, you coated cloth such as black paint.
[0051]
With this mask 42, only the light reflected from the same sample surface 41 can be detected.
[0052]
Note that the opening of the mask may be freely formed according to the measurement sample.
[0053]
The present invention can be applied to a wide range of fields such as spectroscopic measurement, analytical chemistry, surface measurement, surface modification, surface treatment, ruins, archeology, non-destructive analysis of valuable samples, storage, and storage.
[0054]
In addition, this invention is not limited to the said Example, A various deformation | transformation is possible based on the meaning of this invention, and these are not excluded from the scope of the present invention.
[0055]
【The invention's effect】
As described above in detail, according to the present invention, the following effects can be obtained.
[0056]
(A) Nondestructive measurement can be performed without processing the surface of the sample.
[0057]
(B) By variably measuring the incident angle on the sample, the diffuse reflection component can be continuously changed, and a compact and high-quality reflection spectrum measuring apparatus can be configured.
[0058]
(C) Using a spheroid mirror, the light collection rate can be maximized by placing the sample at one focal position and the photodetector at the other focal position.
[0059]
(D) Further, in addition to this, the inner surface of the spheroid mirror is, for example, a metal-plated mirror, thereby making it possible to reduce the spectral background and estimate the diffuse reflection component spectrum with higher quality. Become. That is, information of so-called transmission absorption spectrum can be obtained from the reflection spectrum, and information useful for qualitative measurement of the material surface can be provided.
[0060]
(E) By applying a mask to the sample and detecting only the light reflected from the surface of the same sample, accurate diffuse reflection can be performed by an incident light beam having a fixed irradiation area.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of a reflection spectrum measuring apparatus showing a first embodiment of the present invention.
FIG. 2 is a schematic diagram showing an incident state of infrared light on a sample of the reflection spectrum measuring apparatus according to the first embodiment of the present invention.
FIG. 3 is a reflection spectrum measurement flowchart showing the first embodiment of the present invention.
FIG. 4 is a diagram showing a series of reflection spectra obtained by the photodetector of the reflection spectrum measuring apparatus according to the first embodiment of the present invention.
FIG. 5 is a diagram showing a result of integration processing of a series of reflection spectra obtained by the photodetector of the reflection spectrum measuring apparatus according to the first embodiment of the present invention.
FIG. 6 is a diagram showing separation results of absorption spectrum candidate data among a series of reflection spectrum integration processing results obtained by the photodetector of the reflection spectrum measuring apparatus according to the first embodiment of the present invention.
FIG. 7 is a diagram showing a differential processing result after separating absorption spectrum candidate data out of a series of reflection spectrum integration processing results obtained by the photodetector of the reflection spectrum measuring apparatus according to the first embodiment of the present invention. is there.
FIG. 8 is a diagram showing separation results of specular reflection spectrum candidate data among a series of reflection spectrum integration processing results obtained by the photodetector of the reflection spectrum measuring apparatus according to the first embodiment of the present invention.
FIG. 9 is a diagram showing a differential processing result after separating specular reflection spectrum candidate data from a series of reflection spectrum integration processing results obtained by the photodetector of the reflection spectrum measuring apparatus according to the first embodiment of the present invention; It is.
FIG. 10 is a diagram showing a three-time integration graph of a spectrum as an example of non-negative conversion.
FIG. 11 is a diagram showing a true absorption spectrum of a film prepared by dissolving a polystyrene plate and an estimated absorption spectrum obtained by the present invention.
FIG. 12 is a schematic diagram of a reflection spectrum measuring apparatus showing a second embodiment of the present invention.
FIG. 13 is a block diagram of a reflection spectrum measuring apparatus (part 1) showing a third embodiment of the present invention.
FIG. 14 is a configuration diagram of a reflection spectrum measuring apparatus (part 2) showing a third embodiment of the present invention.
FIG. 15 is an explanatory diagram of setting a reflecting surface of a sample.
FIG. 16 is an explanatory diagram of a mask as a pretreatment of a sample according to an embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Rotating ellipsoidal mirror 2 Infrared light source 3 Sample 4 Photodetector 5 Rotation drive mechanism 6 Computer (measuring device)
DESCRIPTION OF SYMBOLS 7 Photo detector mounting stage 8 Photo detector mounting stage adjustment apparatus 10 Fixed ellipsoidal mirror 10A Aperture 11 Fixed light source 12 Light source body 13 Reflecting mirror 14 Sample stage 15 Sample position setting device 21, 24 Groove (opening)
22, 23 Focus 31 Incident light beam 41 Sample surface 42 Mask

Claims (7)

In the reflection spectrum measuring device,
(A) an ellipsoidal mirror;
(B) a light source;
(C) a sample placed in the ellipsoidal mirror;
(D) a photodetector arranged in the ellipsoidal mirror;
(E) comprising a computer connected to the photodetector ;
( F ) Driving the sample to be arranged at one focal point of the elliptical mirror, the photodetector to be arranged at the other focal point of the elliptical mirror, and the incident angle of light incident on the sample to be variable And a reflection spectrum measuring apparatus. 2. The reflection spectrum measuring apparatus according to claim 1 , wherein a light source is fixed to the ellipsoidal mirror, and the ellipsoidal mirror can be driven by a rotation driving mechanism. 2. The reflection spectrum measuring apparatus according to claim 1 , further comprising a stage and an adjusting device that make the detection angle of the photodetector variable. 2. The reflection spectrum measuring apparatus according to claim 1 , wherein a groove is formed in the ellipsoidal mirror, and the light source is movably disposed. 2. The reflection spectrum measuring apparatus according to claim 1 , wherein the inner surface of the elliptical mirror is a metal-plated mirror. 2. The reflection spectrum measuring apparatus according to claim 1 , further comprising an opening through which light from a light source passes through a part of the elliptical mirror. 2. The reflection spectrum measuring apparatus according to claim 1 , wherein a mask is applied to the sample and only the light reflected from the same sample surface is detected.

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