JPH02268252A - Method for measuring reflectivity of material - Google Patents

Abstract

PURPOSE:To simplify the constitution of an apparatus and to make it possible to measure reflectivity in any wavelength region by computing with a specified expression the output intensity of an optical sensor and stored required data, and obtaining the reflectivity of a material to be measured. CONSTITUTION:The radiation spectrum of a light source for the control parameter of a variable radiation spectrum means 12 is measured beforehand in a light source 11. Said light source 11 is used. The light from the light source 11 is reflected from a material to be measured 30 at a certain control parameter (j). The light is projected on an optical sensor 10. Output intensity Aj of the light outputted from the optical sensor 10 is measured with a detecting part 14 in an operating means 13. Then a wavelength region is arbitrarily divided into (n) parts. Of the light rays which are emitted from the light source 11 whose control parameter (j) is set, the amount of emitted light Pji in a wavelength region (i), the output intensity Aj, the spectral sensitivity Ri of the optical sensor 10 in the wavelength region (i) and the amount of emitted light Bi which is projected on the optical sensor 10 directly in the same wavelength region are substituted for the terms of the expression (j=1, 2,...m, and m>=n). Simultaneous equations for the obtained reflectivity (ri) are operated, and the reflectivity (r) is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a measurement method for measuring the reflectance of a plate-shaped substance using an optical sensor.

(Prior art) Reflectance measurement of a flat plate-shaped substance at a predetermined wavelength is performed by measuring the output intensity of an optical sensor when an object to be measured is installed using an optical sensor, and the output intensity when no object to be measured is installed. It was measured by finding the ratio of

That is, as shown in FIG. 19, light from a white light source 50 is focused by a condensing mirror 51 and enters a spectroscope 52, which separates the light into monochromatic light of a certain wavelength. After the harmonics superimposed on the monochromatic light of the specific wavelength λ are removed by the long-pass filter 53, the light is again focused by the condensing mirror 54, reflected by the object to be measured 56, and irradiated onto the optical sensor 55. At this time, there is a relationship between the output intensity A output from the optical sensor 55, the light indicator P irradiated to the optical sensor 55, the spectral sensitivity R1 of the optical sensor 55, and the desired reflectance r of the object to be measured 56. A=r·R−P The relationship (2) holds true.

In addition, in the measurement optical system shown in FIG.
In the case where the optical sensor 55 is directly irradiated with light without installing the optical sensor 55, the relationship A-=R-shaP (2') similarly holds true. From these equations (2) (2°), r=A/A
-, and by determining the ratio of the output intensities of the optical sensor 55 for each wavelength, the reflectance of the object to be measured 56 can be determined.

The graph shown in FIG. 20 is obtained by repeating such operations for each wavelength λ and determining the reflectance r of the object to be measured 56 in a predetermined wavelength range. The object to be measured (germanium plate) shown in this figure has a maximum reflectance in the wavelength range of 0.2 to 1 μm, so it is suitable for use when it is desired to reflect only light in this wavelength range. It is recognized that the substance is

(Problems to be Solved by the Invention) However, such a conventional method for measuring reflectance has a disadvantage in that the measurement optical system requires a large-scale device. In other words, the conventional device includes at least a white light source, a plurality of condensing mirrors, a spectroscope, a drive device for driving the spectroscope, a long-pass filter to prevent harmonics from being mixed in, a switching mechanism for the long-pass filter, and an optical sensor. A recording device or the like is required to record the output.

In addition, since conventional measurement equipment requires a spectrometer, when splitting light from a white light source into monochromatic light, the prism or grating must be changed depending on the wavelength range of the light to be split. This results in cumbersome operations.

The present invention has been made in view of the problems of the prior art, and provides a measurement method that can measure the reflectance of a substance with a simple device and can also measure the reflectance in any wavelength range. The purpose is to provide a method.

[Structure of the Invention] (Means for Solving the Problems) The present invention for achieving the above object is directed to a light source to which at least n mutually independent radiation spectrum waveforms are given by a radiation spectrum variable means. The optical sensor is irradiated with at least the n lights after being reflected by the optical sensor, and at this time the at least n lights output from the optical sensor are
A method of measuring the reflectance of the object to be measured in each of the wavelength regions of the light divided into n using output intensities of The amount of light emitted from the light source in the divided wavelength region (indicated by subscript i) is Pji.

The output intensity of the optical sensor when irradiated with light having a certain radiation spectrum is Ajl. The spectral sensitivity of the optical sensor in a certain divided wavelength region is Ri.

In the same wavelength region, the amount of radiation that is directly irradiated onto the optical sensor without being reflected by the object to be measured is Bi1, and in the same wavelength region, when the reflectance of the object to be measured is ri, (j=1° 2゜S However, m≧n) From equation (1) given by, the reflectance of the object to be measured (
This is a method for measuring the reflectance of a substance, characterized by determining r i).

(Function) In the present invention configured as described above, the reflectance of the object to be measured can be measured by the following procedure.

First, a light source is used whose radiation spectrum, that is, the amount of emitted light or the radiance with respect to the wavelength, has been measured in advance with respect to the control parameters as the radiation spectrum variable means. Then, under a certain control parameter (denoted by subscript j), the light from this light source is reflected on the object to be measured and the reflected light is irradiated onto the optical sensor, and at this time, the output intensity Aj output from the optical sensor is measured. .

Next, the wavelength range is arbitrarily divided into n, and among the light emitted from the light source for which the control parameter j is set, the amount of emitted light Pji in a certain wavelength range i, the output intensity Aj measured above, and the output intensity Aj in a certain wavelength range are calculated. The spectral sensitivity Ri of the optical sensor at i, and the amount of emitted light Bi directly irradiated onto the optical sensor without being reflected by the object to be measured in the same wavelength region.

By substituting and calculating the simultaneous equations for the reflectance ri obtained by substituting the following equation into the following formula, (j=1.2....2m1, where m≧n), the material in the arbitrarily divided wavelength range can be calculated. The reflectance r can be determined.

(Example) Hereinafter, one embodiment of the present invention will be described based on the drawings.

Fig. 1 is a basic configuration diagram showing an apparatus for measuring the reflectance of a measured object using the measurement method of the present invention, and Fig. 2 shows the light source of the measurement apparatus when the detection field of the optical sensor is smaller than the light source. FIGS. 3 to 7 are block diagrams showing the light source, light sensor, and correction device portions of the measuring device when the detection field of view of the light sensor is larger than the light source,
FIG. 8 is a configuration diagram showing the light source and optical sensor portions of the same measuring device according to another embodiment in the case where the detection field of view of the optical sensor is larger than the light source.

As shown in FIG. 1, the measuring device of this embodiment includes an object to be measured 30 formed in a flat plate shape, an optical sensor 10, and a white light source 11 that irradiates the optical sensor 10 with light having a specific radiation spectrum. , radiation spectrum changing means 12 for changing the waveform of the radiation spectrum of this white light source 11, and calculation means 13 for performing various calculations.

In this embodiment, a black body furnace is used as the white light source 11. As is well known, the blackbody furnace 11 is a complete radiator, and includes a blackbody made of a cylindrical tube housed in a crucible, platinum filled in the crucible so as to contain the blackbody, and a crucible made of platinum. The crucible is made of thoria powder, which is embedded throughout the crucible to improve thermal insulation, and white light is generated by heating the black body through platinum using a heating means such as a high-frequency heating coil installed around the crucible. ing. The white light emitted from the blackbody furnace 11 has the characteristic that its radiation spectrum, that is, the relationship between the wavelength λ of the light and the radiance RI, changes independently depending on the heating temperature of the blackbody. . In other words, it has the characteristic of generating light having a specific radiation spectrum depending on the heating temperature of the blackbody furnace 11, and furthermore, these lights are independent of each other, that is, the radiance simply changes in a similar manner. Rather, it has the characteristic that the waveforms of the radiance with respect to the wavelength λ are different. Therefore, in this embodiment, the radiation spectrum changing means 12 is set to the heating temperature T of the blackbody furnace 11, and the light source emits light having an independent radiation spectrum waveform for one specific heating temperature. I am trying to generate it from 11.

Further, the optical sensor 10 is installed at a position facing the direction of the light emitted from the light source 11, and an object to be measured 30 is disposed between the light source 11 and the optical sensor 10. There is. The object to be measured 30, the light source 11, and the optical sensor IO are housed in a predetermined sealed container filled with dry nitrogen gas. This can prevent absorption of light by water vapor, carbon dioxide, etc. in the atmosphere.

The calculation means 13 includes a detection section 14 that detects the output intensity A of the optical sensor 10, a storage section 15 that stores necessary data in advance, and inputs these output intensity A and necessary data to detect the measured object. It has a calculation section 16 that calculates the reflectance r of 30, and can be configured by a microcomputer or the like. In this embodiment, a DC voltmeter is used as the detection unit 14 that detects the output intensity A of the optical sensor 10, and the storage unit 15 stores information about the amount of emitted light P of the light source 11 with respect to the heating temperature T of the blackbody furnace 11. Stores data.

Further, a recording means 17 for recording the reflectance r of the object to be measured 30 with respect to the wavelength λ calculated by the calculation unit 16 may be connected to the calculation unit 16.

As shown in FIG. 2, when the detection field of view α of the optical sensor 10 is smaller than the size of the lights 1g and lf,
Although measurement can be performed only with the above-mentioned device configuration, as shown in FIG. Since the light is irradiated onto the optical sensor 10, measurement is performed using a detection field of view correction device as described below.

This correction device uses a member (18) that can calculate the amount of emitted light in advance using a theoretical formula.
1 can be regarded as a new light source having a predetermined relationship with the current light source, and has the feature that measurement can be performed without causing an error from an actual measurement value.

That is, first, as shown in FIG.
The output intensity A of the optical sensor 10 is measured while the surface of the baffle plate 18 is blackened and the temperature is controlled to be the same as the room temperature. is substituted into equation (3), which will be described later.

At this time, the light ff1Pl irradiated onto the optical sensor 10 includes light 11rP reflected from the light source 11 and emitted from the object 30 as shown in FIG. 7, and the baffle plate 18.
This includes the amount of light (mainly infrared rays) emitted from the The latter light amount is different from that of the baffle plate 18 (FIG. 4) in which the through holes 19 are formed, since the baffle plate 18 whose surface is blackened can be regarded as a black body at room temperature, that is, a perfect radiator. From the light ff1Po emitted from the baffle plate 20 (FIG. 5) in which the through hole is not formed and which is arranged at the same position, the light ff1Po is located at the same position as the baffle plate 18 (FIG. 4) in which the through hole 19 is formed. The value obtained by subtracting the amount of light P2 emitted from the baffle plate 21 (FIG. 6), which has the same shape as the through hole arranged in the hole (PO-P2)
becomes. Therefore, the required light amount P1 is PL = rp
+(PO-P2) (5), where each value of P, PO, and P2 can be calculated easily and accurately using a blank radiation equation. In other words, when the detection field of view of the optical sensor 10 is larger than the size of the light source 11, by using the above-mentioned detection field of view correction device, it can be regarded as a measurement optical system equipped with a new light source that emits a light amount of Pl. be.

Note that for measurements when the detection field of view of the optical sensor 10 is larger than the size of the light source 11, instead of the baffle plate 18, as shown in FIG. This can also be done by installing an optical element 22 such as a lens.

In this case, it is preferable to use a mirror 22 whose reflectance of light emitted from the light source 11 after passing through the object 30 is 100%, and the amount of light emitted from the surface of the mirror 22 whose reflectance is 100% is 0, so the optical sensor 10
The amount of light irradiated on the object is only the amount of light reflected from the object to be measured 30 from light #, 11. Therefore, even in this case, the amount of light emitted from the light source 11 can be calculated from the optical characteristics of the mirror 22, that is, the F member or aperture and focal length, the geometric arrangement of the light source 11 and the mirror 22, etc. Thereby, the reflectance r of the object to be measured 30 can be determined in the same way as the measurement optical system shown in FIG. 1 described above.

Next, the analysis principle in the measurement method of the present invention will be explained.

As mentioned above, since the blackbody furnace 11 is a perfect radiator, its radiation spectrum, that is, the relationship between the radiance and the wavelength λ of light, is a blank expressed as a function of the wavelength λ and the furnace temperature T. It is determined by the radiation formula.

That is, the radiation spectrum from M3[λ
, Tl (W/m3), wavelength λ (m), and furnace temperature T (K), this radiation spectrum is Mc[λ
, Tl −C1・λ−′ (exp (C2/λT)−11・
...(6) It is expressed as follows. Here, C,, C2 are constants determined from Blank's constant, Boltzmann's constant, and the speed of light in vacuum, and C+ = 3.7xlQ20 C2 = 1.4x107.

First, the wavelength range (λS to λE) in which the reflectance of the object to be measured 30 is to be determined is arbitrarily divided into n parts.

This division does not need to be equal. For example, if the reflectance area of the object to be measured 30 is predicted in advance, highly accurate measurement results can be obtained by subdividing the area at the rising edge of the high reflectance area. This makes it preferable for the use of the present invention.

Also, when dividing this wavelength region (λ, ~λE),
If the boundary value of the spectral sensitivity range of the optical sensor 10 that is the object to be measured, that is, the value such that (spectral sensitivity) = 0 in the shorter wavelength region and longer wavelength region than the light, can be predicted in advance. , let the boundary values be λ5 and λ mentioned above.

If such a prediction cannot be made, the boundary value on the short wavelength side of the wavelength range is set to λS, and the boundary value on the long wavelength side is set to λE.
Set (1) as

Once, this wavelength division was λ, ~λ1~λ2...λn-1~λ8,
For convenience, this wavelength range is defined as λI+ ■2+ ...λ. -1,zu.

as well as Z1=[λ1-1. λ1 However, λ. =λ5,λ. =λ8 It is expressed as

Next, when light of a certain radiation spectrum selected by the radiation spectrum variable means is irradiated from the light source 11 to the optical sensor 10, a certain divided wavelength region [λ1-1. The amount of light emitted by λ1 is P(
2+), when the temperature of the blackbody furnace 11 is T (K), the wavelength range [λ1-1. λ1]
If the amount of light of the component in is L d (Z1), (i = 1. 2..., n), then if this amount of emitted light P is rectangularly approximated to λ, P (λ1) =LT (Xt) (λ1-λ, -1)...(8
) Also, as mentioned above, the amount of light irradiated to the optical sensor includes the amount of light r(Σ1)・P(Σ1) that is emitted from the light source, reflected by the object to be measured, and then irradiated to the optical sensor, and The light ff1B (Σ
1) is included.

Therefore, the amount of light irradiated to the optical sensor is r (f
) "P ('L) p) - B (L). Depending on the configuration of the measurement device, there may be cases where no light is irradiated from the measurement optical system to the optical sensor, In this case, in the above formula, B(2
+)” It should be treated as 0.

Light amount r(s1)・p()I)+ in wavelength region 1
When the light of B(Xl) is irradiated on the optical sensor 10, the optical sensor 10 is as follows: R(At)(r(Z+) P(Σ1)
)) will be output. Here, since the relationship between the amount of irradiated light and the output intensity is established independently in each wavelength region, it is assumed that the relationship between the amount of irradiated light and the output intensity is established independently in each wavelength region.
The output intensity of the optical sensor 10 when irradiated with light of λE] is measured as the sum of contributing components from each wavelength region. Therefore, the measured output intensity of the optical sensor is +B (s1)) (j=1.2. . . . , n) .
It is expressed as (3). Note that PTI (Σ1) represents the amount of emitted light in the wavelength region S1 when the temperature of the blackbody furnace 11 is T. In addition, ATI indicates that the temperature of the blackbody furnace 11 is T.
represents the measured output intensity of the optical sensor when . Here, if we transform the above equation (3), we get: In this case, the left side of the above equation is the measured value obtained by measurement, and the PTI (L) and R (S1) on the right side are values known in advance. .

Therefore, the above equation (3) is expressed as the unknown quantity r(L
), r(Z2), -r(2°) It becomes an n-element linear simultaneous equation. Then, PTl (Σ+), P engineering 2 (Z 1), ... P engineering. (Z 1) uses light sources with mutually independent radiation spectra, so that the detection field of view α of the optical sensor 1o is
If the size is smaller than 1, the above (6)
(7) By using equation (8), and as shown in FIG.
8) (7) By using equation (8), the corresponding (3
) can be solved for r(2,).

In the embodiments described above, a case has been described in which the type of radiation spectrum from the light source 11 obtained by changing the temperature T of the blackbody furnace 11 is equal to the number n of divided wavelength regions. The present invention is not limited to the embodiments, as long as there are n or more types of radiation spectra. In this case, since the number of equations obtained by the equation (1) is greater than the number of unknowns to be found, the equations can be solved by the method of least squares.

Next, other embodiments of the present invention will be described with reference to FIGS. 9 to 17. The first embodiment described above is an example in which the reflectance r of the object to be measured 30 is determined by measuring the DC output signal of the optical sensor 10 with respect to the irradiated light.
The second embodiment described below is a specific example in which the reflectance r of the object to be measured 30 is determined by measuring the alternating current output signal of the optical sensor 10 in response to light from the light source 11 modulated to an arbitrary frequency.

Fig. 9 is a block diagram showing an apparatus for measuring the reflectance of an object to be measured using the measurement method according to the second embodiment, and Figs. A configuration diagram showing the light source and the optical sensor part of the measurement device, a graph showing the relationship between the amount of light irradiated by the optical sensor and time, and Figures 12 to 17 show the same measurement when the detection field of the optical sensor is larger than the light source. It is a block diagram which shows the light source of an apparatus, an optical sensor, and a correction|amendment apparatus part, and a graph which shows the relationship between the amount of light irradiated by an optical sensor, and time.

As shown in FIG. 9, the measuring device of the present embodiment includes an object to be measured 30, which is a component of the first embodiment described above, an optical sensor 10, and a light beam having a specific radiation spectrum to the optical sensor 10. a white light source 11 that irradiates the white light #, 11;
In addition to radiation spectrum changing means 12 for changing the waveform of the radiation spectrum of
The light source 1 is provided between the object to be measured 30 and the optical sensor 10.
It has a frequency modulation device 23 that modulates the light from 1 into light of a predetermined frequency.

Further, an amplifier 24 is connected to the output terminal of the optical sensor 10 to amplify the output signal to increase the signal strength, and furthermore, the amplified output signal is modulated by a frequency modulation device 23. A lock-in amplifier 25 is connected to the lock-in amplifier 25 for detecting the AC waveform.The amplifier 24 does not need to be provided if the output signal from the optical sensor 10 is sufficiently large. This amplifier 24 may also be applied.

There are various other possible means for extracting only the alternating current portion modulated by the frequency modulation device 23 from the output signal of such an optical sensor. For example, you can simply connect an AC voltmeter to the output terminal of the optical sensor to measure the average voltage, or you can connect a DC converter to the output terminal of the optical sensor and then connect a DC voltmeter to measure the DC voltage. It can also be measured. Furthermore, the frequency modulation device 23 modulates the center layer wave number of the output signal of the optical sensor by a CR active filter.
It is also possible to measure the modulation frequency with an AC voltmeter, or with a DC voltmeter via a DC converter.

The frequency converter 23 has a chopping blade 27 whose surface is blackened and whose temperature is controlled to be the same as room temperature, and in which through holes 26 through which light from the light source 11 passes are formed at predetermined intervals. This chopping blade 2
7 is provided with a drive unit 28 that rotates the chopping blade 27 at a certain speed. The through hole 26 is formed to be larger than the detection field of the optical sensor 10. Further, the reference signal output from the drive unit 28 of the frequency modulation device 23 is transmitted to the lock-in amplifier 25.
It is wired so that it is input to the

The calculation means 13 includes a storage section 15 that stores necessary data in advance, and the output intensity A and the necessary data transmitted from the lock-in amplifier 25 and manually calculates the output intensity A and the necessary data to the object to be measured 30.
It has a calculation unit 16 that calculates the reflectance r of , and can be configured by a microcomputer or the like. Also in this embodiment, the storage unit 15 stores data on the emitted light ff1P of the light source 11 with respect to the heating temperature T of the blackbody furnace 11.

Further, a recording means 17 for recording the reflectance r of the object to be measured 30 calculated by the calculation section 16 may be connected to the calculation section 16.

In this embodiment configured in this way, the object to be measured 30
Since the frequency modulation device 23 is installed between the optical sensor 10 and the optical sensor 10, the optical sensor 10 is also irradiated with light (mainly infrared rays) emitted from the modulation device 23. Therefore, in the measuring device according to this embodiment, the amount of light rP emitted from the light source 11, reflected by the object to be measured 30, and irradiated onto the optical sensor 10 by the measuring device shown in FIG.
The light ff1 obtained by subtracting the light ff1P3 emitted from the chopping blade 27 of the modulation device 23 shown in FIG.
It can be regarded as a measurement optical system having a new light source of (rP-P3) (see FIG. 11). Here, the light quantities P and P3 can be calculated in the same manner as in the first embodiment.

As shown in FIG. 10, the detection field of view α of the optical sensor 10 is
If the size of the light source 11 is smaller than the size of the light source 11, it can be measured only by the above-mentioned device configuration.
As shown in FIG. 12, when the detection field β of the optical sensor 10 is larger than the size of the light source 11, the measurement optical system is irradiated with light from sources other than the light source 11. Measurement is performed using the same detection field of view correction device as in the first embodiment.

This correction device uses a member (29) that can calculate the amount of emitted light using a theoretical formula in advance, so that the actual light source 1
1 can be regarded as a new light source having a predetermined relationship with the current light source, and has the feature that measurement can be performed without causing an error from an actual measurement value.

That is, first, as shown in FIG. 12, a baffle plate 29 in which a through hole 31 is formed in order to limit the detection field of view β of the optical sensor 10 to be less than the size of the light source 11 is connected to the object to be measured 30 and the frequency modulator 23. The output intensity A of the optical sensor 10 was measured while the surface of the baffle plate 29 was blackened and the temperature was controlled to be the same as room temperature, and this measured value A was obtained as described above ( 3) Substitute into the equation.

At this time, the light ff1Pl irradiated onto the optical sensor 10 shown in FIG. 12 is equal to the amount of light rP reflected from the light source 11 and irradiated onto the object 30 as shown in FIG. As shown in FIG. The light ff1P2 emitted from the baffle plate corresponding to the formed through hole 31 and the light f detected by the optical sensor 10 when the chopping blade 27 blocks the light from the light source 11 as shown in FIG.
The light amount is obtained by subtracting the light amount obtained by adding f1P3, that is, PL = rP + PO - P2 - P3 - (9).

These rP, PO, PL, P2. The relationship of P3 is as shown in FIG.

Here, P, PO, P2. Each value of P3 can be calculated easily and accurately using a blank radiation equation. In other words, when the detection field of view of the optical sensor 10 is larger than the size of the light source 11, by using two consecutive detection field of view correction devices, it is regarded as a measurement optical system equipped with a new light source that emits a light amount of Pl. This is the translation.

Even in this embodiment configured in this way, the reflectance ri of the object to be measured can be calculated using equation (3) detailed in the first embodiment.
By solving the simultaneous equations in the arithmetic means 13, it is possible to obtain the reflectance in an arbitrarily divided wavelength region.

Note that the present invention is not limited to the first and second embodiments described above, and various modifications are possible, and in particular, the embodiments of the measuring device may be modified in various ways as long as they meet the requirements of the present invention. is applicable. For example, in the embodiment, a blackbody furnace is used as the light source, but a lamp that can generate mutually independent radiation spectra depending on the filament current value may also be used.

Next, the reflectance measuring method of the present invention will be explained by giving more specific examples.

In this specific example, measurements were performed using the device configuration shown in FIG.
The measurement results are shown in FIG.

In this specific example, the object to be measured 3 in FIG.
0 uses a germanium single crystal plate with a thickness of 2 mm,
The object to be measured 30 is arranged at an angle of 45° with respect to the traveling direction of the light irradiated from the blackbody furnace 11.

On the other hand, a blackbody furnace was used as the light source 11, and a microcomputer was used as the calculation means 13. Also,
As the radiation spectrum changing means 12, a temperature controller of a blackbody furnace was used, and the temperature controller was controlled by the microcomputer. Here, the blackbody furnace 11
, frequency modulation device 23, object to be measured 30, and optical sensor 10
was housed in a closed container filled with dry nitrogen gas to remove the effects of water vapor, carbon dioxide, etc. in the atmosphere.

As measurement conditions, the modulation frequency in the frequency modulator 23 is 8 Hz, and the temperature of the black body furnace 11 is 200 to 100 Hz.
The temperature was measured in 100°C units between 0°C (473 and 1273K). In addition, the division wavelengths of the light source are 0.2, 1.0, 4.0, 7.0.10.0, 1
3.0, 16.0, 19.0.22.0.100.0
There were 9 divisions of μm.

The amount of radiation from the blackbody furnace is obtained at each set temperature using the blank radiation equation described above, and the obtained simultaneous equations (9-element linear simultaneous equations) are calculated using the Gaussian elimination method using the microcomputer. Calculated by.

Figure 18 shows the above measurement results (indicated by the solid line in the figure) and, as a comparative example, the reflectance measured by the conventional measurement method (indicated by the broken line in the figure). From this, it can be understood that the accuracy of the measuring method of the present invention is excellent.

[Effects of the Invention] As described above, according to the present invention, the reflectance of a substance can be measured with an extremely simple device configuration, and furthermore,
Reflectance can be measured in any wavelength range.

[Brief explanation of drawings]

Fig. 1 is a basic configuration diagram showing an apparatus for measuring the reflectance of a measured object using the measurement method of the present invention, and Fig. 2 shows the light source of the measurement apparatus when the detection field of the optical sensor is smaller than the light source. FIGS. 3 to 7 are block diagrams showing the light source, light sensor, and correction device portions of the measuring device when the detection field of view of the light sensor is larger than the light source,
FIG. 8 is a configuration diagram showing the light source and optical sensor portion of the same measuring device according to another embodiment in which the detection field of view of the optical sensor is larger than the light source, and FIG. Figures 10 and 11, which are block diagrams showing an apparatus for measuring the reflectance of a measured object using such a measurement method, show the light source and optical sensor portion of the measuring apparatus when the detection field of view of the optical sensor is smaller than the light source. Configuration diagram and graph showing the relationship between the amount of light irradiated by the optical sensor and time, 12th to 17th
The figure shows a configuration diagram showing the light source, the photosensor, and the correction device portion of the measuring device when the detection field of view of the photosensor is larger than the light source, and a graph showing the relationship between the amount of light irradiated by the photosensor and time. The figure is a graph showing the results of reflectance measurement according to a specific example of the present invention, and Figures 19 and 20 are a configuration diagram showing a measuring device using a conventional reflectance measuring method, and graphs showing data obtained by measurement. It is. DESCRIPTION OF SYMBOLS 10... Optical sensor, 11... Light source, 12... Radiation spectrum changing means, 13... Calculating means, 30...
Object to be measured. Patent Applicant Nippon Steel Corporation Agent Patent Attorney 8 1) Mikio (1 other person) Figure 1 Figure 1-0 Figure 41 Tei Tsuryu Figure 17 Shikawa Saiko Value KC Layer Procedure Amendment June 7, 1999

Claims (1)

[Scope of Claims] A light source that is provided with at least n mutually independent radiation spectrum waveforms by a radiation spectrum variable means,
After being reflected by the object to be measured, at least the n
In this method, the reflectance of the object to be measured is measured in each of the n wavelength regions of the light divided by the at least n output intensities outputted from the optical sensor at this time. So, for light with a certain emission spectrum (denoted by the subscript j),
Pji is the amount of emitted light from the light source in a certain divided wavelength region (represented by subscript i); Aj is the output intensity of the optical sensor when irradiated with light having a certain emission spectrum; Ri is the spectral sensitivity of the optical sensor, Bi is the amount of radiation that is directly irradiated to the optical sensor without being reflected by the object to be measured in the same wavelength region, and ri is the reflectance of the object to be measured in the same wavelength region. When, Aj-Σ＾n_i_=_1(Bi・Ri) =Σ＾n_i_=_1(ri・Pji・Ri)...
...(1) (j = 1, 2, ..., m) However, m≧n)
From equation (1) given by, the reflectance of the object to be measured (
A method for measuring the reflectance of a substance, characterized by determining ri).