JP4879197B2 - Measuring device that measures the optical rotation of the measurement object - Google Patents

Description

  The present invention relates to a measuring apparatus that measures the optical rotation of a measurement target.

2. Description of the Related Art Conventionally, an optical rotation measuring device (polarimeter) for measuring the optical rotation and concentration of a substance having optical activity such as sugars and amino acids is known. As such a polarimeter, a multi-wavelength polarimeter with an expanded measurement wavelength is known. As such a technique, there is a conventional technique disclosed in, for example, Japanese Patent Laid-Open No. 2000-39361.
JP 2000-39361 A

  However, in the conventional polarimeter, it is necessary to manually replace a plurality of filters having different wavelengths, and there is a problem that the operation is complicated and unusable. In addition, in order to expand the measurement wavelength, use a plurality of monochromatic light sources with different wavelengths, detect the light intensity at all wavelengths using a spectroscope, branch the detection side with a half mirror or beam splitter, It is conceivable to arrange a filter that transmits a predetermined wavelength in front of each detector. However, the method using a plurality of monochromatic light sources or the method using a spectroscope has a problem that the apparatus becomes large and expensive, and the method using a half mirror or the like has a problem that the light intensity after branching decreases. there were.

The present invention has been made in view of the problems as described above, and the object is as follows.
An object of the present invention is to provide a measuring apparatus capable of measuring the optical rotation of multiple wavelengths with a simple configuration.

(1) The present invention is a measuring device for measuring the optical rotation of a measurement object,
A first polarizer that transmits a predetermined polarization component of light;
A polarization modulation unit that modulates light transmitted through the first polarizer into arbitrary polarization;
A second polarizer that transmits a predetermined polarization component of the light transmitted through the measurement object via the polarization modulator;
A dichroic mirror that transmits a predetermined wavelength component of light transmitted through the second polarizer and reflects a wavelength component other than the predetermined wavelength component;
A first filter that transmits a first wavelength of light transmitted through the dichroic mirror;
A second filter that transmits a second wavelength of light reflected from the dichroic mirror;
A first detector for detecting the light intensity of the light transmitted through the first filter;
And a second detector for detecting the light intensity of the light transmitted through the second filter.

  According to the present invention, by dividing the light transmitted through the second polarizer using a dichroic mirror, it is possible to detect the light intensities of a plurality of wavelengths without reducing the light intensity before the division.

(2) In the measuring device according to the present invention,
The polarization modulator is
A first parallel alignment liquid crystal element and a second parallel alignment liquid crystal element having different principal axis orientations;
And a voltage controller for controlling a voltage applied to the first parallel alignment liquid crystal element and the second parallel alignment liquid crystal element.

  According to the present invention, the polarization modulator is configured by two liquid crystal elements whose principal axis directions are shifted, so that the apparatus can be miniaturized and driven at a low voltage. Further, by controlling the voltage applied to the two liquid crystal elements, the birefringence phase difference between the two liquid crystal elements can be changed at high speed.

(3) In the measuring apparatus according to the present invention,
When the voltage corresponding to the first wavelength is applied by the voltage control unit, the optical rotation of the measurement object at the first wavelength is calculated based on the light intensity detected by the first detection unit. Perform computations,
When the voltage corresponding to the second wavelength is applied by the voltage control unit, the optical rotation of the measurement object at the second wavelength is calculated based on the light intensity detected by the second detection unit. An arithmetic processing unit that performs arithmetic processing is further included.

Even if the applied voltage to the liquid crystal voltage is the same, the birefringence phase difference obtained differs depending on the wavelength. That is, in order to obtain a predetermined birefringence phase difference, it is necessary to apply different voltages depending on the wavelength.
Therefore, according to the present invention, when the voltage for the first wavelength is applied, the optical rotation of the first wavelength is calculated based on the light intensity detected by the first detector, and the second wavelength When the voltage is applied, the optical rotation at the second wavelength is calculated based on the light intensity detected by the second detection unit, so that the optical rotation for each different wavelength can be measured with high accuracy.

  Hereinafter, this embodiment will be described. In addition, this embodiment demonstrated below does not unduly limit the content of this invention described in the claim. In addition, all the configurations described in the present embodiment are not necessarily essential configuration requirements of the present invention.

1. Configuration of Measuring Device FIG. 1 is a block diagram for explaining the configuration of the measuring device of the present embodiment. The measuring device 1 is a device that measures the optical rotation of a sample 100 that is a measurement target. The measuring device 1 includes an optical system 10 and a control device 40. The control device 40 includes an arithmetic processing unit 50, which performs arithmetic processing for calculating the optical rotation of the sample 30 based on the optical elements included in the optical system 10 and the light intensity transmitted through the sample 30. Hereinafter, the device configuration of the measuring device 1 will be described.

1-1. Optical system 10
The optical system 10 includes a light source 12, a polarizer 18 (first polarizer) that transmits a predetermined polarization component of light from the light source 12, and polarization modulation that modulates light transmitted through the polarizer 18 into arbitrary polarization. Unit 20, analyzer 32 (second polarizer) that transmits a predetermined polarization component of light transmitted through sample 30 (measurement target) via polarization modulator 20, and predetermined light of light transmitted through analyzer 32 A dichroic mirror 80 that transmits a wavelength component other than the predetermined wavelength component, a first filter 82 that transmits a first wavelength of light transmitted through the dichroic mirror 80, and a dichroic mirror 80. The second filter 84 that transmits the second wavelength of the reflected light, the first detection unit 34 that detects the light intensity of the light transmitted through the first filter 82, and the light that has passed through the second filter 84 Light intensity And a second detector 36 for detecting. Each will be described below.

  The light source 12 is a white light source such as a tungsten halogen lamp, and emits white light including a wide range of wavelength components.

  The collimating lens 13 converts white light from the light source 12 guided by the optical fiber into parallel light. The mirror 14 reflects this parallel light and makes it incident on the polarizer 18.

  The polarizer 18 is an incident-side polarizer that converts the parallel light reflected by the mirror 14 into linearly polarized light. That is, the polarizer 18 transmits linearly polarized light having a polarization plane in the direction of the transmission axis (main axis direction). The polarizer 18 of this embodiment is installed so that the principal axis direction is 0 ° in the horizontal direction.

The polarization modulator 20 modulates the linearly polarized light transmitted through the polarizer 18 into arbitrary polarized light. The polarization modulation unit 20 includes a liquid crystal element 21 including a first liquid crystal cell 22 (first parallel alignment liquid crystal element) and a second liquid crystal cell 24 (second parallel alignment liquid crystal element), and first and first liquid crystal cells. The first and second voltage control units 23 control the voltages applied to the two liquid crystal cells 22 and 24 and change the birefringence phase differences δ ₁ and δ ₂ of the first and second liquid crystal cells 22 and 24, respectively. , 25 and a temperature control unit 26 for controlling the temperature of the liquid crystal element 21.

  The first liquid crystal cell 22 installed in front of the light advance direction has a main axis in a direction rotated 45 ° counterclockwise toward the light advance direction with respect to the main axis direction (horizontal 0 °) of the polarizer 18. The second liquid crystal cell 24 installed on the back side in the light traveling direction has a main axis parallel to the main axis direction (horizontal 0 °) of the polarizer 18. Accordingly, the principal axis directions of the first and second liquid crystal cells 22 and 24 are deviated from each other by 45 °. The first liquid crystal cell 22 has a main axis direction inclined by an odd multiple of 45 ° with respect to the main axis direction of the polarizer 18, and the second liquid crystal cell 24 has 45 ° with respect to the main axis direction of the polarizer 18. It is also possible to have a principal axis orientation that is inclined by an even number of times.

As described above, the phase modulation is performed using the two liquid crystal cells 22 and 24 whose principal axis directions are 45 ° and 0 °, respectively, and the birefringence phase differences δ ₁ and δ ₂ are variable. The transmitted predetermined linearly polarized light can be changed to arbitrary linearly polarized light, elliptically polarized light or circularly polarized light.

  FIGS. 2A, 3 </ b> A, and 3 </ b> B are diagrams schematically illustrating the liquid crystal element 21 including the first and second liquid crystal cells 22 and 24 of the present embodiment. . FIG. 2A is a top view of the liquid crystal element 21.

  As shown in FIG. 2A, each of the first and second liquid crystal cells 22 and 24 includes two transparent substrates TS, a transparent electrode EL provided on the inner surface of the transparent substrate TS, and two transparent substrates. It is constituted by nematic liquid crystal LC sealed between the substrates TS. An alignment film AL1 is provided at the interface between the transparent substrate TS and the nematic liquid crystal LC in the first liquid crystal cell 22, and an alignment film AL2 is provided at the interface between the transparent substrate TS in the second liquid crystal cell 24 and the nematic liquid crystal LC. It has been. The two liquid crystal cells 22 and 24 are overlapped on the transparent substrate TS to constitute one liquid crystal element 21. Here, the transparent substrate TS where the two liquid crystal cells are overlapped may be one, and the transparent substrate TS constituting the liquid crystal element 21 may be three as shown in FIG. 2B. . At this time, the transparent electrode EL and the alignment film AL are provided on both surfaces of the central transparent substrate TS.

  3A is a front view of the liquid crystal element 21 (front view of the first liquid crystal cell 22), and FIG. 3B is a rear view of the liquid crystal element 21 (front view of the second liquid crystal cell 24). ).

  As shown in FIG. 3A, in the first liquid crystal cell 22, the rubbing direction (alignment direction) RD is 45 ° with respect to the reference direction HD, and the main axis direction of birefringence is thus 45 °. It has become. Further, as shown in FIG. 3B, the second liquid crystal cell 24 has a rubbing direction (alignment direction) RD of 0 ° with respect to the reference direction HD, whereby the main axis direction of birefringence is also 0 °. It has become. That is, the rubbing treatment direction applied to the alignment film AL1 (see FIG. 2A) of the first liquid crystal cell 22 is 45 ° with respect to the reference direction HD, and the alignment film of the second liquid crystal cell 24 The rubbing process applied to AL2 (see FIG. 2A) is 0 ° with respect to the reference direction HD. In the second liquid crystal cell 24, the rubbing direction RD may be 90 ° with respect to the reference direction HD. The reference direction HD is the same direction as the main axis direction (horizontal 0 °) of the polarizer 18.

  Thus, by setting the rubbing directions of the first and second liquid crystal cells 22 and 24 to 45 ° and 0 ° (or 90 °), respectively, one of the first and second liquid crystal cells 22 and 24 is The principal axis directions of the two liquid crystal cells 22 and 24 can be shifted from each other by 45 ° without being inclined at 45 ° with respect to the other. Therefore, the first and second liquid crystal cells 22 and 24 can be overlapped and integrated in parallel. And the apparatus can be reduced in size by comprising the polarization modulation part 20 with the liquid crystal element 21 which comprised the 1st and 2nd liquid crystal cells 22 and 24 integrally.

  FIG. 4 is a diagram schematically illustrating the polarization modulation unit 20 of the present embodiment.

  The polarization modulation unit 20 includes a temperature control unit 26 that controls the temperature of the liquid crystal element 21. The temperature control unit 26 includes a copper case CC, a temperature sensor TS, a Peltier element PD, a heat sink HS, and a cooling fan CF, and the temperature of the liquid crystal element 21 formed by integrating the first and second liquid crystal cells 22 and 24. Is controlled to be constant. The liquid crystal element 21 is housed in a copper case CC using copper having excellent heat conduction. Further, a temperature sensor TS such as a thermistor for detecting the temperature of the copper case CC and a Peltier element PD (thermoelectric element) for cooling (heat absorption) or heating the copper case CC are provided at a position in contact with the copper case CC. A heat sink HS (heat radiating plate) for dissipating the heat of the Peltier element PD is provided at a position in contact with the Peltier element PD, and a cooling fan CF is attached below the heat sink HS to supplement the heat diffusion capability of the heat sink HS. It has been. The copper case CC is provided with an opening OM through which incident light to the liquid crystal element 21 passes and an opening OM (not shown) through which light emitted from the liquid crystal element 21 passes, and the Peltier element PD and the heat sink HS are provided with In addition, an opening OM through which incident light to the liquid crystal element 21 passes is provided.

  As shown in FIG. 4, by controlling the temperature of the liquid crystal element 21 to be constant by using the temperature control unit 26 including the copper case CC, the temperature sensor TS, the Peltier element PD, the heat sink HS, and the cooling fan CF, It is possible to prevent an error (fluctuation) from occurring in the birefringence phase difference of the first and second liquid crystal cells 22 and 24 with respect to the same applied voltage due to a change in environmental temperature. Further, by using the temperature control unit 26 to control the temperature of the liquid crystal element 21 formed by integrating the first and second liquid crystal cells 22 and 24, the liquid crystal element 21 and the temperature control unit 26 can be controlled. The device can be configured in an integrated manner, and the apparatus can be downsized as compared with the case where a temperature control unit is provided for each of two liquid crystal cells that are not integrated (the temperature of each liquid crystal cell is individually controlled). .

  Referring again to FIG. 1, the analyzer 32 is an output-side polarizer that uses light that has passed through the sample 30 as linearly polarized light. That is, the analyzer 32 transmits linearly polarized light having a polarization plane in the direction of the transmission axis (main axis direction). The polarizer 32 of this embodiment is installed so that the principal axis direction is horizontal 45 °.

  The dichroic mirror 80 transmits a predetermined wavelength component of the light transmitted through the analyzer 32 and reflects a wavelength component other than the predetermined wavelength component.

  FIG. 5 is a diagram showing the transmittance and reflectance of the dichroic mirror 32 of the present embodiment. As shown in FIG. 5, the dichroic mirror 32 of the present embodiment is a hot mirror, transmits light having a short wavelength including the first wavelength (589 nm), and light having a long wavelength including the second wavelength (880 nm). Reflect.

  Referring to FIG. 1 again, the first filter 82 (interference filter, band pass filter) transmits the first wavelength of the light transmitted through the dichroic mirror 32. The first filter 82 of the present embodiment transmits light having a center wavelength of 589 nm as the first wavelength.

  The first detection unit 34 is composed of, for example, a photoelectric sensor such as a photodiode, detects the light intensity of light (first wavelength light) transmitted through the first filter 82, converts the light intensity into voltage, and provides light intensity information. Output as.

  The second filter 84 (interference filter, bandpass filter) transmits the second wavelength of the light reflected by the dichroic mirror 32. The second filter 84 of the present embodiment transmits light having a center wavelength of 880 nm as the second wavelength.

  The second detection unit 36 includes a photoelectric sensor such as a photodiode, for example, detects the light intensity of light (second wavelength light) transmitted through the second filter 84, converts the light intensity into voltage, and outputs light intensity information. Output as.

  6A is a diagram showing the spectral characteristics of white light emitted from the light source 12, and FIG. 6B is a diagram showing the spectral characteristics of the light transmitted through the dichroic mirror 32, and FIG. C) is a diagram showing the spectral characteristics of the light reflected by the dichroic mirror 32. FIG.

  As shown in FIG. 6B and FIG. 6C, light transmitted through the first filter 82 (first wavelength light) and light transmitted through the second filter 84 (second The light intensity of the light (wavelength light) is not lowered even by the division by the dichroic mirror 32. By using the dichroic mirror 32 in this way, it is possible to detect the light intensities of a plurality of measurement wavelengths (first and second wavelengths) while maintaining the light intensity before the division.

1-2. Control device 40
The control device 40 includes an arithmetic treatment unit 50, a control signal generation unit 60, and a storage unit 70.

  The calculation processing unit 50 performs calculation processing for calculating the optical rotation of the sample 30 at the first wavelength based on the light intensity information output from the first detection unit 34. The calculation processing unit 50 performs calculation processing for calculating the optical rotation of the sample 30 at the second wavelength based on the light intensity information output from the second detection unit 36. That is, when the voltage corresponding to the first wavelength is applied by the first and second voltage control units 23 and 25, the arithmetic processing unit 50 uses the light intensity information output from the first detection unit 34. Based on this, the optical rotation of the sample 30 at the first wavelength is calculated, and when a voltage corresponding to the second wavelength is applied by the first and second voltage control units 23 and 25, the second detection unit Based on the light intensity information output from 36, the optical rotation of the sample 30 at the second wavelength is calculated.

The control signal generation unit 60 generates a control signal to control the first and second voltage control units 23 and 25 (liquid crystal drivers of the liquid crystal cells of the first and second liquid crystal cells 22 and 24), The birefringence phase differences δ ₁ and δ ₂ of the first and second liquid crystal cells 22 and 24 are changed.

  Further, the control signal generation unit 60 controls the operation of the temperature control unit 26. For example, a control signal is generated based on the output from the temperature sensor TS shown in FIG. 4, and the operation of the Peltier element PD or the cooling fan CF shown in FIG. 4 is controlled to control the temperature of the liquid crystal element 21 to be constant.

The storage unit 50 has a function of temporarily storing various data. For example, the light intensity information output from the first and second detection units 34 and 36 is stored in the first and second liquid crystal cells 22 and 24. The birefringence phase differences δ ₁ and δ ₂ are stored in association with each other.

2. Optical rotation measurement principle Next, the optical rotation measurement principle employed by the measurement apparatus of the present embodiment will be described.

2-1. Theoretical expression of the light intensity of the light detected by the detection unit 34 When the Stokes parameter of the monochromatic light incident on the polarizer 18 is S _in and the Stokes parameter of the light transmitted through the sample 30 and emitted from the analyzer 32 is S ′. , S ′ can be expressed by the following equation.

Note that I ₀ is the light intensity of monochromatic light incident on the polarizer 18. P _{0 °} is a Mueller matrix of the polarizer 18 whose principal axis direction is 0 °. The _R δ1,45 _° is the Mueller matrix of the first liquid crystal cell 22 birefringence phase difference is the principal axis direction is 45 ° is [delta] _1. The _R δ2,0 _° is the Mueller matrix of the second liquid crystal cell 24 the principal axis direction is ₂ birefringent phase difference δ is 0 °. _Tφ is the Mueller matrix of the sample 30 whose optical rotation is φ. A _{45 °} is a Mueller matrix of the analyzer 32 whose principal axis orientation is 45 °.

Here, if the light intensity of the light detected by the first and second detection units 34 and 36 is I (δ ₁ , δ ₂ , φ), the I (δ ₁ , δ ₂ , φ) is the analyzer 32. S ₀ ′ of the Stokes parameter of the light emitted from

It becomes.

2-2. Calculation principle of the optical rotation of the sample 30 The optical rotation of the sample 30 is obtained as follows by measuring the light intensity of the light passing through the sample 30 and the analyzer 32 while changing the polarization state of the light incident on the sample 30. .

For example, the birefringence phase differences δ ₁ and δ ₂ of the first and second liquid crystal cells 22 and 24 are set as δ ₁ = δ and δ ₂ = δ + π / 2, and δ is continuously from 0 ° to 360 °. Change. At this time, assuming that the light intensity detected by the first and second detectors 34 and 36 is I (δ, δ + π / 2, φ), the I (δ, δ + π / 2, φ) is expressed by the equation (2). Than,

It becomes. Where _a (= I 0 / _4sin2φ) and _b (= I 0 / _8cos2φ) indicate respectively the coefficients of the Fourier function cosδ and Sin2deruta. From equation (3), it can be seen that when δ is continuously modulated in the range of 0 ° to 360 °, the light intensity I (δ, δ + π / 2, φ) changes periodically. Therefore, a periodic change in the light intensity I (δ, δ + π / 2, φ) detected by the first and second detectors 34 and 36 is Fourier analyzed, and the coefficients a and b are obtained to obtain the optical rotation φ of the sample 30. Is

(Fourier transform method).

In addition, the birefringence phase differences δ ₁ and δ ₂ of the first and second liquid crystal cells 22 and 24 are set to 2 kπ, (2l + 1/2) π, (2m + 1) π, and (2n + 3/2) π (k, l), respectively. , M and n are each an integer) and four times modulation, and from the four light intensity values detected by the first and second detectors 34 and 36 at this time, the optical rotation φ of the sample 30 is

Can be calculated. Here, I ₁ , I ₂ , I ₃ , and I ₄ respectively indicate the birefringence phase differences δ ₁ and δ ₂ of the first and second liquid crystal cells 22 and 24 to 0, π / 2, π, and 3π / 2, respectively. The light intensity detected by the first and second detectors 34 and 36 when set. According to this method (phase modulation method, 4-step phase shift method), the birefringence phase differences δ ₁ and δ ₂ of the first and second liquid crystal cells 22 and 24 need only be modulated four times. φ can be calculated at high speed.

3. Multi-wavelength optical rotation measurement technique Next, a multi-wavelength optical rotation measurement technique employed by the measurement apparatus of the present embodiment will be described.

  The birefringence phase difference Δ (λ) at a certain wavelength λ is expressed as follows:

It can be expressed as. In other words, in the present embodiment, the voltages applied to the first and second liquid crystal cells 22 and 24 are controlled to change the birefringence phase differences δ ₁ and δ ₂ of the first and second liquid crystal cells 22 and 24. However, even if the applied voltages to the first and second liquid crystal cells 22 and 24 are the same, the birefringence phase differences δ ₁ and δ ₂ obtained by the wavelengths are different.

  FIG. 7 is a diagram showing the relationship between the voltage applied to the liquid crystal cell and the birefringence phase difference. Here, the horizontal axis represents the applied voltage, and the vertical axis represents the obtained birefringence phase difference. The solid line shows the relationship between the applied voltage and the birefringence phase difference at the first wavelength (589 nm), and the dotted line shows the relationship between the applied voltage and the birefringence phase difference at the second wavelength (880 nm). As shown in FIG. 7, in order to obtain a predetermined birefringence phase difference at the first wavelength, a larger applied voltage is required as compared with the case at the second wavelength. Therefore, when using a calculation method (4-step phase shift method, Fourier transform method) that gives a fixed birefringence phase difference to incident light, it is necessary to apply different applied voltages at different wavelengths and detect the light intensity for each wavelength. There is.

  FIG. 8 is a diagram illustrating a time chart when the 4-step phase shift method is performed with two wavelengths (first wavelength and second wavelength).

8 shows a time chart of birefringence phase differences δ ₁ and δ ₂ given to the first and second liquid crystal cells 22 and 24. Here, the birefringence phase differences δ ₁ and δ ₂ are phase-modulated four times to 2π, π / 2, π, and 3π / 2.

Reference numeral 120 in FIG. 8 shows a time chart of voltages applied to the first and second liquid crystal cells 22 and 24. In the present embodiment, first, voltages are applied so that the birefringence phase differences δ ₁ and δ ₂ are 2π, π / 2, π, and 3π / 2 at the first wavelength (589 nm), and then the second wavelength. A voltage is applied so that the birefringence phase differences δ ₁ and δ ₂ are 2π, π / 2, π, and 3π / 2 at (880 nm). As shown at 120 in FIG. 8, each applied voltage for the first wavelength is larger than each applied voltage for the second wavelength. Note that the voltage applied to the liquid crystal cell is 500 ms per phase modulation.

  Reference numeral 130 in FIG. 8 shows a time chart of light intensity detection by the first detector 34. In the present embodiment, the first detection unit 34 detects the light intensity of the light transmitted through the first filter 82 every time the voltage for the first wavelength is applied, and corresponds to four phase modulations. Then, the light intensity of the first wavelength light is detected four times. Note that an interval of 375 ms from the start of one voltage application (phase modulation) to the stabilization of the liquid crystal is taken, and the light intensity is detected in the remaining 125 ms.

  140 of FIG. 8 shows a time chart of light intensity detection by the second detector 36. In the present embodiment, the second detection unit 36 detects the light intensity of the light transmitted through the second filter 84 every time the voltage for the second wavelength is applied, and corresponds to four phase modulations. The light intensity of the second wavelength light is detected four times.

  Reference numeral 150 in FIG. 8 shows a time chart for calculating the optical rotation by the arithmetic processing unit 50 and displaying the calculation result. In the present embodiment, the arithmetic processing unit 50 calculates the optical rotation at the first wavelength based on the four light intensities detected by the first detection unit 34 after the light intensity detection by the first detection unit 34, The calculation result is displayed on the display unit. The arithmetic processing unit 50 calculates the optical rotation at the second wavelength based on the four light intensities detected by the second detection unit 36 after the light intensity is detected by the second detection unit 36, and displays the calculation result. Displayed in the section. In addition, since one phase modulation is performed in 500 ms, in the 4-step phase shift method in which four phase modulations are performed, the measurement result of the optical rotation angle of the first wavelength and the measurement result of the optical rotation angle of the second wavelength Can be displayed alternately every 2 seconds.

  As described above, according to the present embodiment, it is possible to realize high-speed multi-wavelength optical rotation measurement close to real time by using the polarization modulation unit configured by two liquid crystal cells and capable of high-speed phase modulation by an electric signal. .

  In addition, this invention is not limited to the above-mentioned embodiment, A various deformation | transformation is possible. The present invention includes configurations that are substantially the same as the configurations described in the embodiments (for example, configurations that have the same functions, methods, and results, or configurations that have the same objects and effects). In addition, the invention includes a configuration in which a non-essential part of the configuration described in the embodiment is replaced. In addition, the present invention includes a configuration that exhibits the same operational effects as the configuration described in the embodiment or a configuration that can achieve the same object. Further, the invention includes a configuration in which a known technique is added to the configuration described in the embodiment.

  For example, in the present embodiment, a case where a hot mirror that reflects light having a long wavelength is used as the dichroic mirror has been described. However, a cold mirror that reflects light having a short wavelength may be used.

  It can be used not only for measuring the concentration of soft drinks and fruits, but also for analyzing molecular structures such as proteins, amino acids, and nucleic acids, and for quality control of chemicals. Moreover, it can utilize as a blood glucose level sensor which measures a blood glucose level.

The block diagram for demonstrating the structure of the measuring device of this embodiment. The figure which shows typically the liquid crystal element comprised from the 1st and 2nd liquid crystal cell of this embodiment. The figure which shows typically the liquid crystal element comprised from the 1st and 2nd liquid crystal cell of this embodiment. The figure which shows typically the polarization modulation part of this embodiment. The figure which shows the transmittance | permeability and reflectance of the dichroic mirror of this embodiment. 6A, 6B, and 6C show the spectral characteristics of white light emitted from the light source, the spectral characteristics of light transmitted through the dichroic mirror, and the spectral characteristics of light reflected from the dichroic mirror. FIG. The figure which shows the relationship between the voltage applied to a liquid crystal cell, and a birefringence phase difference. The figure which shows the time chart in the case of performing a 4-step phase shift method by 2 wavelengths (1st wavelength, 2nd wavelength).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Measuring apparatus, 10 Optical system, 12 Light source, 13 Collimate lens, 14 Mirror, 18 Polarizer, 20 Polarization modulation part, 21 Liquid crystal element, 22 1st liquid crystal cell, 23 1st voltage control part, 24 2nd Liquid crystal cell, 25 second voltage control unit, 26 temperature control unit, 30 sample, 32 analyzer, 34 first detection unit, 36 second detection unit, 40 control device, 50 arithmetic processing unit, 60 control signal generation Part, 70 storage part, 80 dichroic mirror, 82 first filter, 84 second filter

Claims (1)

A measuring device for measuring the optical rotation of a measurement object,
A first polarizer that transmits a predetermined polarization component of light;
A polarization modulation unit that modulates light transmitted through the first polarizer into arbitrary polarization;
A second polarizer that transmits a predetermined polarization component of the light transmitted through the measurement object via the polarization modulator;
A dichroic mirror that transmits a predetermined wavelength component of light transmitted through the second polarizer and reflects a wavelength component other than the predetermined wavelength component;
A first filter that transmits a first wavelength of light transmitted through the dichroic mirror;
A second filter that transmits a second wavelength of light reflected from the dichroic mirror;
A first detector for detecting the light intensity of the light transmitted through the first filter;
A second detector for detecting the light intensity of the light transmitted through the second filter;
An arithmetic processing unit that performs arithmetic processing to calculate the optical rotation of the measurement object,
The polarization modulator is
A first parallel alignment liquid crystal element and a second parallel alignment liquid crystal element having different principal axis orientations;
A voltage controller for controlling a voltage applied to the first parallel alignment liquid crystal element and the second parallel alignment liquid crystal element,
The arithmetic processing unit includes:
When the voltage corresponding to the first wavelength is applied by the voltage control unit, the optical rotation of the measurement object at the first wavelength is calculated based on the light intensity detected by the first detection unit. An arithmetic process is performed, and when the voltage corresponding to the second wavelength is applied by the voltage control unit, the measurement target of the second wavelength is detected based on the light intensity detected by the second detection unit. A measuring apparatus that performs arithmetic processing for calculating an optical rotation .

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