JP2703326B2 - How to measure the transmittance of a substance - Google Patents

Description

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

(Prior art) Measurement of transmittance of a plate-shaped substance at a predetermined wavelength is as follows.
The measurement is performed by obtaining a ratio between the output intensity of the optical sensor when the object to be measured is installed using the optical sensor and the output intensity when the object to be measured is not installed.

That is, as shown in FIG. 19, light from the white light source 50 is condensed by the condensing mirror 51 and is incident on the spectroscope 52, where the light is split into monochromatic light of a certain wavelength. Then, after removing the harmonics superimposed on the monochromatic light having the specific wavelength λ by the long-pass filter 58, the condensing mirror is returned again.
The light is condensed by 54, passes through the DUT 56, and is
Irradiation. At this time, between the output intensity A output from the optical sensor 55, the light amount P irradiated to the device under test 56, the spectral sensitivity R of the optical sensor 55, and the transmittance τ of the device under test 56 to be obtained. , A = τ · R · P (2).

In the case where the object to be measured 56 is not installed in the measuring optical system shown in FIG. 19, the relationship of A ′ = R · P (2 ′) is similarly established. From these equations (2) and (2 ′), τ = A / A ′, and the transmittance of the device under test 56 can be determined by determining the ratio of the output intensity of the optical sensor 55 for each wavelength.

This operation is repeated for each wavelength λ, and the transmittance τ of the device under test 56 is determined in a predetermined wavelength region, as shown in the graph of FIG. DUT (Germanium plate) shown in this figure
Has a maximum transmittance in a wavelength region of 1 to 22 μm, and thus is a suitable substance to be used when it is desired to transmit only light in this wavelength region.

(Problems to be Solved by the Invention) However, according to such a conventional method for measuring the transmittance, there is a disadvantage that the apparatus of the measuring optical system becomes large. That is, the conventional apparatus includes at least a white light source, a plurality of condenser mirrors, a spectroscope, a driving device for driving the spectroscope, a long-pass filter for preventing harmonics from being mixed, a switching mechanism of the long-pass filter, and an optical sensor. A recording device or the like for recording the output is required.

In addition, since a spectroscope is indispensable for the conventional measuring device,
When the light from the white light source is split into monochromatic light, an extremely troublesome operation of changing the prism or the grating is required depending on the wavelength region of the split light.

The present invention has been made in view of such problems of the conventional technology, and can measure the transmittance of a substance with a simple device, and can measure the transmittance in any wavelength region. The aim is to provide a method.

[Means for Solving the Problems] To achieve the above object, the present invention provides a device for measuring an object to be measured from a light source to which at least n independent radiation spectrum waveforms are given by radiation spectrum variable means. And irradiates the light sensor with at least the n light beams. At this time, at least n output intensities output from the light sensor cause the measured light to be measured in each of the n wavelength divided light regions. A method for measuring the transmittance of an object, wherein the amount of light emitted from the light source in a divided wavelength region (represented by a subscript j) of light having a certain radiation spectrum (represented by a subscript j) is represented by Pji, The output intensity of the optical sensor when irradiating light having a radiation spectrum is Aj, the spectral sensitivity of the optical sensor in a certain divided wavelength region is Ri, and the spectral sensitivity is in the same wavelength region. There are, radiation amount of irradiated the direct said light sensor without passing through the object to be measured Bi, in the same wavelength region, the transmittance of the measured object when the .tau.i, The transmittance (τi) of the object to be measured is obtained from the equation (1) given by the following formula (1).

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

First, a light source is used in which the emission spectrum of the light source for each control parameter of the emission spectrum varying means, that is, the amount of radiation or radiance with respect to wavelength is measured in advance.
Then, under a certain control parameter (represented by a subscript j), the object to be measured is transmitted from the light source to irradiate the optical sensor with light. At this time, the output intensity Aj output from the optical sensor is measured.

Next, the wavelength region is arbitrarily divided into n, and of the light emitted from the light source in which the control parameter j is set, the amount of radiation Pji in a certain wavelength region i, the measured output intensity Aj, and the certain wavelength region Spectral sensitivity of optical sensor at i
Ri, the amount of radiation Bi irradiated to the optical sensor without passing through the object to be measured in the same wavelength region, and By calculating the simultaneous equations for the transmittance τi obtained by substituting the values into, the transmittance τ of the substance in the arbitrarily divided wavelength region can be obtained.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a basic configuration diagram showing an apparatus for measuring the transmittance of an object to be measured using the measuring method of the present invention, and FIG. 2 is a light source of the same measuring apparatus when the detection field of view of the optical sensor is smaller than the light source. FIG.
FIG. 8 is a configuration diagram showing a light source, an optical sensor, and a correction device portion of the measuring device when the detection field of view of the optical sensor is larger than the light source. FIG. It is a lineblock diagram showing a light source and an optical sensor part of the same measuring device.

As shown in FIG. 1, the measuring apparatus of the present embodiment includes a device under test 30 formed in a flat plate shape, an optical sensor 10, and a white light source 11 for irradiating the optical sensor 10 with light having a specific radiation spectrum. And emission spectrum changing means 12 for changing the waveform of the emission spectrum of the white light source 11, and operation means 13 for performing various operations.

In this embodiment, a black body furnace is used as the white light source 11. As is well known, the black body furnace 11 is a complete radiator, and includes a black body formed of a cylindrical tube housed in a crucible, platinum filled in the crucible so as to include the black body, and a crucible. It is composed of tria powder etc. which bury the whole to improve thermal insulation, and white light is generated by heating the black body via platinum by heating means consisting of high frequency heating coil etc. provided around the crucible. ing. The white light emitted from the black body furnace 11 has a characteristic that its emission spectrum, that is, the relationship between the wavelength λ of the light and the radiance Me independently changes according to the heating temperature of the black body. . In other words, it has a characteristic of generating light having a specific emission spectrum with respect to the heating temperature of the black body furnace 11, and these lights are independent of each other.
In other words, the radiance Me does not simply change in a similar manner, but has a specification that the waveforms of the radiance Me with respect to the wavelength λ have different waveforms. Therefore, in the present embodiment, the radiation spectrum changing means 12 is
And the heating temperature T, and for one specific heating temperature,
Light source having independent independent radiation spectrum waveform
I'm trying to generate from 11.

The optical sensor 10 is installed at a position facing the direction of light emitted from the light source, and a device under test 30 is provided between the light source 11 and the optical sensor 10. . The DUT 30, the light source 11, and the optical sensor 10 are housed in a predetermined closed container filled with dry nitrogen gas. Thereby, absorption of light by water vapor or carbon dioxide in the atmosphere can be prevented.

The calculation means 13 includes a detection unit 14 for detecting the output intensity A of the optical sensor 10 and a storage unit for storing necessary data in advance.
15 and an operation unit 16 which inputs the output intensity A and necessary data to calculate the transmittance τ of the device under test 40, and can be constituted by a microcomputer or the like. In the present embodiment, a DC voltmeter is used as the detection unit 14 for detecting the output intensity A of the optical sensor 10, and
15 stores data on the amount of radiation P of the light source 11 with respect to the heating temperature T of the blackbody furnace 11.

A recording unit 17 for recording the transmittance τ of the device under test 30 with respect to the wavelength λ calculated by the arithmetic unit 16 is provided by the arithmetic unit.
It can also be configured to connect to 16.

As shown in FIG. 2, when the detection field α of the optical sensor 10 is smaller than the size of the light source 11, the measurement can be performed only by the above-described apparatus configuration.
As shown in the figure, when the detection field of view β of the optical sensor 10 is larger than the size of the light source 11, light from a source other than the light source 11 is applied to the optical sensor 10 to the measurement optical system. The measurement is performed using a detection field correction device.

This correction device uses the member (18) for which the amount of radiation can be calculated in advance by a theoretical formula, thereby realizing the actual light source 11
Can be regarded as a new light source having a predetermined relationship with the light source, and has a feature that the measurement can be performed without an error from an actual measurement value.

That is, first, as shown in FIG. 4, a through hole 19 is formed to limit the detection field β of the optical sensor 10 to the size of the light source 11 or less.
The baffle plate 18 on which is formed is disposed between the DUT 30 and the optical sensor 10, and the surface of the baffle plate 18 is blackened and the optical sensor 10 is adjusted to the same temperature as room temperature.
Is measured, and the measured value A is described later (3).
Substitute in an expression.

At this time, the light amount P1 applied to the optical sensor
As shown in the figure, the light amount τP transmitted from the light source 11 through the DUT 30 and the light amount (mainly infrared light) emitted from the baffle plate 18 are included. The latter amount of light can be regarded as a black body at room temperature, that is, a complete radiator, since the baffle plate 18 whose surface is blackened can be regarded as a complete radiator.
From the amount of light P0 radiated from the baffle plate 20 (FIG. 5), which is disposed at the same position as that of FIG. 4
(P0-P2) obtained by subtracting the amount of light P2 emitted from the baffle plate 21 (FIG. 6) having the same shape as the through hole disposed at the same position as that shown in FIG. Therefore, the light quantity P1 to be obtained is: P1 = τP + (P0−P2) (5) where the respective values of P, P0, and P2 are accurately and easily calculated using Planck's radiation equation. can do. 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-described correction device for the detection field, it is regarded as a measurement optical system including a new light source that emits the light amount P1. is there.

When the detection field of view of the optical sensor 10 is larger than the size of the light source 11, the measurement is performed between the DUT 30 and the optical sensor 10 as shown by a solid line in FIG.
Alternatively, an optical element 22 such as a mirror or a lens may be provided between the light source 11 and the device under test 30, as indicated by a dashed line.

In this case, it is preferable to use a mirror 22 having a reflectance of 100% for light emitted from the light source 11 through the device 30. The amount of light emitted from the surface of the mirror 22 having a reflectance of 100% is preferably used. Since it is 0, the amount of light applied to the optical sensor 10 is only the amount of light transmitted from the light source 11 through the DUT 30. Therefore, also in this case, the optical characteristics of the mirror 22, that is, the F member or the aperture and the focal length,
The amount of light radiated from the light source 11 can be calculated from the geometrical arrangement of the light source 11 and the mirror 22, and the transmittance of the DUT 30 can be calculated in the same manner as in the measurement optical system shown in FIG. τ can be obtained.

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

As described above, since the blackbody furnace 11 is a perfect radiator, its radiation spectrum, that is, the relationship of the radiance Me with respect to the wavelength λ of light, is a plank expressed as a function of the wavelength λ and the furnace temperature T. It is obtained by the radiation equation.

That is, the radiance from the blackbody furnace 11 is expressed as Me [λ, T] (W /
m ³ ), the wavelength is λ (m), and the furnace temperature is T (K), this emission spectrum is expressed as Me [λ, T] = C ₁ λ ^-5 {exp (C ₂ / λT) -1} ... (6) Here, C ₁ and C ₂ are constants determined from Planck's constant, Boltzmann's constant, and the speed of light in a vacuum, and C ₁ = 1.191 × 10 ⁻¹⁶ [W · m ² ] and C ₂ = 1.438 × 10 ⁻² [ m · K]. Further, of the light of wavelength λ radiated from the main body 11, the light amount L _T (λ) applied to the optical sensor is represented by A (m ² ), the opening area of the main body, Assuming that the solid angle of the light receiving surface of the optical sensor is Ω (steradian), L _T (λ) = Me [λ, T] · A · Ω (6 ′)

First, a wavelength region (λ _{S to} λ _E ) for which the transmittance of the device under test 30 is to be obtained is arbitrarily divided into n regions. This division does not need to be an equal division.For example, if the transmittance region of the device under test 30 is predicted in advance, subdividing it at the rising portion of the high transmittance region will provide a highly accurate measurement result. This is preferable for utilization of the present invention.

In dividing this wavelength region (λ _{S to} λ _E ),
If the boundary value of the spectral sensitivity range of the optical sensor 10 to be measured, that is, a value such that (spectral sensitivity) = 0 can be predicted in advance in a shorter wavelength range and a longer wavelength range than the light, , The boundary values are λ _S and λ _E described above.

If such a prediction cannot be made, the boundary value on the short wavelength side of the wavelength region is set to 0 as λ _S , and the boundary value on the long wavelength side is set to λ _E
Is set as ∞.

Thus, this wavelength _{division, λ S ~λ 1 ~λ 2 ......} λ n-1 ~λ E , and the convenience of the wavelength regions _{1, 2, ... n-1} , n and _i = _{[λ i-1,} λ _i ] where λ ₀ = λ _S and λ _n = λ _E.

Next, when light of a certain radiation spectrum selected by the radiation spectrum varying means is irradiated from the light source 11 to the optical sensor 10, the aforementioned divided wavelength regions [λ _i-1 , λ ₁ ] Is P
( _I ) When the temperature of the black body furnace 11 is T (K), the light sensor 10
Let L _T ( _i ) be the light amount of the component in the wavelength region [λ _i−1 , λ _i ] of the light irradiated to (I = 1,2 ......, n) since it is, if a rectangular approximation to the emitted light amount _{P λ, P (λ i)} = L T (i) · (λ i -λ i-1 ) (8) As described above, the amount of light applied to the optical sensor includes the amount of light τ ( _i ) · P ( _i ) emitted from the light source and transmitted through the device under test and then applied to the optical sensor. And the amount of light B ( _i ) emitted from the baffle plate or the chopping blade described later, which is a measuring optical system in the middle. Therefore, the amount of light applied to the optical sensor can be expressed as τ ( _i ) · P ( _i ) + B ( _i ). Note that, depending on the configuration of the measuring apparatus, there may be no case where there is no light emitted from the intermediate measuring optical system to the optical sensor. In this case, B ( _i ) may be treated as B ( _i ) = 0 in the above equation.

Light amount τ ( _i ) · P ( _i ) + B in wavelength region _i
When the light of ( _i ) is applied to the optical sensor, the optical sensor 10 outputs a signal having an intensity of R ( _i ) {τ ( _i ) P ( _i ) + B ( _i )}. Here, since the relationship between the irradiated light quantity and the output intensity is established independently in each wavelength region,
The output intensity of the optical sensor 10 when the light of the entire wavelength region, that is, the light of [λ _S , λ _E ] is irradiated, is measured as the sum of the contribution components from each wavelength region. Therefore, the measured output intensity of the optical sensor is: Is represented by Note that P _Tj ( _i ) is the temperature of the blackbody furnace 11.
It represents the amount of radiation in the wavelength region _{i at} T _j .
Also, A _Ti represents the output intensity of the measured light sensor when the temperature of the blackbody furnace 11 is T _j. Here, when the above equation (3) is modified, At this time, the left side is a measured value obtained by measurement, and P _Tj ( _i ) and R ( _i ) on the right side are known values.

Therefore, the above equation (3) gives the unknown τ to be obtained.
( ₁ ), τ ( ₂ ),... Τ ( _n ) are n-ary linear equations. And P _T1 ( _i ), P _T2 ( _i ),
Since P _Tn ( _i ) uses light sources having emission spectra independent of each other, when the detection field α of the optical sensor 10 is smaller than the size of the light source 11, as shown in FIG. By using the equations (6), (6 '), (7), and (8), and as shown in FIG. 3, when the detection field β of the optical sensor 10 is larger than the size of the light source 11, By using the above equations (5), (6), (6 '), (7), and (8), the equation (3) can be solved for τ ( _i ).

In the above-described embodiment, the case where the type of the emission spectrum from the light source 11 obtained by changing the temperature T of the black body furnace 11 is equal to the number n of the divided wavelength regions has been described. The present invention is not limited to the embodiment, and it suffices that the number of types of radiation spectra is n or more. In this case, since the number of equations obtained by the above equation (1) is larger than the number of unknowns to be obtained, the equations can be solved by the least squares method.

Next, another embodiment of the present invention will be described with reference to FIGS. The above-described first embodiment is an example in which the transmittance τ of the device under test 30 is obtained by measuring the DC output signal of the optical sensor 10 with respect to the irradiated light. Light source 11 modulated to an arbitrary frequency
This is a specific example in which the transmittance τ of the device under test 30 is determined by measuring an AC output signal of the optical sensor 10 with respect to light from the device.

FIG. 9 is a block diagram showing an apparatus for measuring the transmittance of an object to be measured by using the measuring method according to the second embodiment. FIGS. 10 and 11 show the same when the detection field of view of the optical sensor is smaller than the light source. FIG. 12 is a configuration diagram showing a light source and an optical sensor portion of a measuring device, and a graph showing a relationship between the amount of light irradiated by the optical sensor and time. FIGS. 12 to 17 show the same measurement when the detection field of the optical sensor is larger than the light source. FIG. 2 is a configuration diagram illustrating a light source, an optical sensor, and a correction device portion of the device, and a graph illustrating a relationship between a light amount irradiated by the optical sensor and time.

As shown in FIG. 9, the measuring apparatus of the present embodiment includes an object to be measured 30 which is a component of the above-described first embodiment, and an optical sensor.
10, a white light source 11 that irradiates the light sensor 10 with light having a specific emission spectrum, and a radiation spectrum changing unit 12 that changes the waveform of the emission spectrum of the white light source 11.
In addition to the calculation means 13 for performing various calculations, the DUT 30
A frequency modulator 23 that modulates light from the light source 11 into light having a predetermined frequency is provided between the optical sensor 10 and the optical sensor 10. Further, an output terminal of the optical sensor 10 is connected to an amplifier 24 for amplifying the output signal to increase the signal strength, and of the amplified output signal, which is modulated by the frequency modulation device 23. A lock-in amplifier 25 for detecting an AC waveform is connected. Note that the amplifier 24 need not be provided when the output signal from the optical sensor 10 is sufficiently large, and the amplifier 24 may be applied to the first embodiment described above.

There are various other means for extracting only the AC portion modulated by the frequency modulation device 23 from the output signal of the optical sensor. For example, simply connect an AC voltmeter to the output terminal of the optical sensor to measure the average voltage, or connect a DC converter to the output terminal of the optical sensor,
Further, a DC voltmeter can be connected to measure this DC voltage. Further, the center frequency of the output signal of the optical sensor is matched with the modulation frequency of the frequency modulation device 23 by the CR active filter, and this is measured by an AC voltmeter or measured by a DC voltmeter through a DC converter. It is also possible.

The frequency conversion device 23 has a chopping blade 27 in which the surface is blackened, and the temperature is adjusted to the same temperature as room temperature, and the through holes 26 through which the light from the light source 11 passes are formed at predetermined intervals, In this chopping blade 27,
A drive unit 28 for rotating the chopping blade 27 at a certain speed is provided. The through hole 26 is formed to be larger than the detection visual field of the optical sensor 10. The reference signal output from the drive unit 28 of the frequency modulation device 23 is connected so as to be input to the lock-in amplifier 25.

The calculating means 13 inputs the output intensity A and necessary data transmitted from the lock-in amplifier 25 and the storage section 15 for storing necessary data in advance, and calculates the transmittance τ of the DUT 30. And an arithmetic unit 16 which can be configured by a microcomputer or the like. Also in the present embodiment, the storage unit 15 stores data of the radiation light amount P of the light source 11 with respect to the heating temperature T of the black body furnace 11.

In addition, a recording unit 17 for recording the transmittance τ of the DUT 30 calculated by the arithmetic unit 16 may be connected to the arithmetic unit 16.

In the present embodiment configured as above, the DUT 30
Since the frequency modulation device 23 is provided between the optical sensor 10 and the optical sensor 10, the light (mainly infrared light) emitted from the modulation device 23 is also applied to the optical sensor 10. Accordingly, the measuring device according to the present embodiment is configured such that the measuring device shown in FIG. 10 uses the measuring device shown in FIG. Light amount (τP-
It can be regarded as a measurement optical system having a new light source of P3) (see FIG. 11). Here, the light amount P and
P3 can be calculated in the same manner as in the first embodiment.

As shown in FIG. 10, when the detection field α of the optical sensor 10 is smaller than the size of the light source 11, the measurement can be performed only by the above-described device configuration.
As shown in the figure, when the detection visual field β of the optical sensor 10 is larger than the size of the light source 11, light from other than the light source 11 is applied to the measuring optical system. The measurement is performed using the same detection field correction device as in the embodiment.

This correction device uses the member (29) that can calculate the amount of radiation in advance by a theoretical formula, thereby realizing the actual light source 11
Can be regarded as a new light source having a predetermined relationship with the light source, and has a feature that the measurement can be performed without an error from an actual measurement value.

That is, first, as shown in FIG. 12, in order to limit the detection field β of the optical sensor 10 to the size of the light source 11 or less, the through hole 31 is used.
The baffle plate 29 on which is formed is disposed between the DUT 30 and the frequency modulation device 23, and the surface of the baffle plate 29 is blackened and the temperature is adjusted to the same temperature as the room temperature. The output intensity A of 10 is measured, and the measured value A is substituted into the above-mentioned equation (3).

At this time, the amount of light applied to the optical sensor 10 shown in FIG.
P1 is a light amount τP transmitted from the light source 11 through the device under test 30 as shown in FIG. 15 and a through hole provided at the same position as the baffle plate 29 as shown in FIG. The amount of light radiated from the baffle plate corresponding to the through hole 31 formed in the baffle plate 29, as shown in FIG. As shown in FIG. 13, the light amount obtained by subtracting the light amount obtained by adding P2 and the light amount P3 detected by the optical sensor 10 when the chopping plate 27 blocks the light from the light source 11, that is, P1 = τP + P0−P2− P3 ... (9) The relationship among τP, P0, P1, P2, and P3 is as shown in FIG.

Here, the respective values of P, P0, P2, and P3 can be accurately and easily calculated using Planck's radiation formula. 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-described correction device for the detection field, it is regarded as a measurement optical system including a new light source that emits the light amount P1. is there.

Even in the present embodiment having such a configuration, the transmittance τ of the object to be measured can be obtained by the expression (3) described in detail in the first embodiment.
A simultaneous equation for i can be obtained, and by solving the simultaneous equation by the calculating means 13, the transmittance in an arbitrarily divided wavelength region can be obtained.

It should be noted that the present invention is not limited to the first and second embodiments described above, and various modifications are conceivable. In particular, the embodiments of the measuring device may be various as long as the requirements of the present invention are satisfied. Can be applied. For example, in the embodiment,
Although a black body furnace was used as the light source, a lamp capable of generating an independent emission spectrum depending on the filament current value can also be applied.

Next, the transmittance measuring method of the present invention will be described with reference to more specific examples.

In this specific example, measurement is performed with the device configuration shown in FIG. 9, and the measurement results are shown in FIG.

In this specific example, the measured object in FIG.
A germanium single crystal plate having a thickness of 2 mm is used for 30, and the DUT 30 is arranged at an angle of 45 ° with respect to the traveling direction of the light emitted from the black body furnace 11.

On the other hand, a black body furnace was used as the light source 11, and a microcomputer was used as the calculating means 13. As the radiation spectrum changing means 12, a temperature controller of a black body furnace was used, and the microcomputer controlled the temperature controller. Here, the black body furnace 11, the frequency modulator 23, the device under test 30, and the optical sensor 10 are housed in an airtight container filled with dry nitrogen gas to remove the influence of water vapor and carbon dioxide in the atmosphere. I did it.

As the measurement conditions, the modulation frequency in the frequency modulation device 23 is 8 Hz, and the temperature of the black body furnace 11 is 200 to 1000 ° C. (473 to 1
273K) in 100 ° C. units. The split wavelength of the light source is 0.2, 1.0, 4.0, 7.0, 10.0, 13.0, 16.0, 19.0, 22.0,
It was divided into 9 sections of 100.0 μm.

At each set temperature, the amount of radiation from the blackbody furnace was determined by the Planck radiation equation described above, and the obtained simultaneous equations (ninth-order linear simultaneous equations) were obtained by Gaussian elimination using the microcomputer. Was calculated.

FIG. 18 shows the measurement results (shown by solid lines in the figure).
And the transmittance (indicated by a broken line in the figure) measured by a conventional measuring method as a comparative example. From these results, it is understood whether the accuracy of the measuring method of the present invention is excellent. can do.

[Effects of the Invention] As described above, according to the present invention, the transmittance of a substance can be measured with an extremely simple apparatus configuration, and the transmittance can be measured in any wavelength region.

[Brief description of the drawings]

FIG. 1 is a basic configuration diagram showing an apparatus for measuring the transmittance of an object to be measured using the measuring method of the present invention, and FIG. 2 is a light source of the same measuring apparatus when the detection field of view of the optical sensor is smaller than the light source. And FIG. 3 to FIG. 7 are configuration diagrams illustrating a light source, an optical sensor, and a correction device portion of the measurement device when the detection field of view of the optical sensor is larger than the light source.
FIG. 8 is a configuration diagram showing a light source and a light sensor part of the measuring apparatus according to another embodiment when the detection field of view of the optical sensor is larger than the light source, and FIG. 9 is a second embodiment of the present invention. Configuration diagram showing an apparatus for measuring the transmittance of an object to be measured using such a measurement method, FIGS. 10 and 11 show a light source and an optical sensor portion of the same measurement apparatus when the detection field of view of the optical sensor is smaller than the light source. FIG. 12 is a configuration diagram, and FIG. 12 to FIG. 17 are graphs showing the relationship between the amount of light emitted by an optical sensor and time, and FIGS. 12 to 17 show a light source, an optical sensor, and a correction device of the same measuring device when the detection field of view of the optical sensor is larger than the light source. A configuration diagram showing
And a graph showing the relationship between the amount of light irradiated by the optical sensor and time, FIG. 18 is a graph showing a measurement result of transmittance according to a specific example of the present invention, and FIGS. 19 to 20 are conventional transmittance measurement methods. FIG. 1 is a configuration diagram showing a measuring device using a graph and a graph showing data obtained by measurement. Reference numeral 10 denotes an optical sensor, 11 denotes a light source, 12 denotes a radiation spectrum changing unit, 13 denotes a calculation unit, and 30 denotes an object to be measured.

Claims (1)

(57) [Claims] At least n light beams are radiated from a light source provided with at least n independent radiation spectrum waveforms by a radiation spectrum varying means to an optical sensor through an object to be measured. A method of measuring the transmittance of the object under measurement in each of n wavelength regions of the light, based on at least n output intensities output from an optical sensor, the light having a certain radiation spectrum (subscript) j))
The amount of radiation of the light source in a certain divided wavelength range (represented by a subscript i) is Pij, the output intensity of the optical sensor when irradiating light having a certain radiation spectrum is Aj, The spectral sensitivity of the optical sensor is Ri, in the same wavelength region, the amount of radiation irradiated directly to the optical sensor without passing through the device under test is Bi, and in the same wavelength region, the transmittance of the device under test is τi. When you do A method for measuring the transmittance of a substance, wherein the transmittance (τi) of the object to be measured is obtained from Expression (1) given by: