Polarimeter and measuring device

Abstract

The present invention provides a polarimeter in which the configuration of the detection unit is simplified even when detecting multiple polarized light sources in parallel over time. [Solution] The polarimeter 1 according to the present disclosure comprises: an optical element 20 including a wave plate 21 into which a first portion L1 of the light L to be measured is incident; a polarizer array 30 including a plurality of polarizers into which the first portion L1 that has passed through the wave plate 21 and the other portion of the light L that has not passed through the wave plate 21 is incident and which have different polarization transmission axes in at least three directions; a reflecting unit 40 including a plurality of mirrors that operate independently of each other with drive signals associated with the polarization-operated light that has passed through the polarizer array 30; a single detection unit 60 that detects the polarization-operated light reflected by the reflecting unit 40; and a control unit 74 that separates the detection signal of the detection unit 60 for each polarization-operated light according to the drive signal and calculates polarization information of the light L.

Description

Technical Field

[0001] The present disclosure relates to a polarimeter and a measuring device.

Background Art

[0002] Conventionally, technologies related to polarimeters are known. For example, in Patent Document 1, a thin polarizer array and a wave plate array composed of minute regions that can set an operating wavelength range by adjusting the characteristics and structure of a material using photonic crystal technology are realized with a high extinction ratio and a low insertion loss, and a polarization analysis device using the same is disclosed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the prior art described in Patent Document 1, in order to detect a plurality of polarization operation lights extracted from incident light in time series, a light receiving element is arranged for each of the plurality of polarization operation lights. As a result, the configuration of the detection unit has become complicated.

[0005] An object of the present disclosure is to provide a polarimeter and a measuring device in which the configuration of a detection unit is simplified even when a plurality of polarization operation lights are detected in time series.

Means for Solving the Problems

[0006] A polarimeter according to some embodiments includes an optical element including a wave plate through which a first portion of light to be measured is incident, the first portion that has passed through the wave plate, and another portion of the light that has not passed through the wave plate, a polarizer array including a plurality of polarizers having polarization transmission axes that are different from each other in at least three orientations, a reflection unit including a plurality of mirrors that operate independently of each other with drive signals respectively associated with the polarization-manipulated light that has passed through the polarizer array, a single detection unit that detects the polarization-manipulated light reflected by the reflection unit, and a control unit that separates the detection signal of the detection unit for each polarization-manipulated light according to the drive signal and calculates the polarization information of the light.

[0007] Thereby, even when a plurality of polarization-manipulated lights are detected in time series, the configuration of the detection unit is simplified. The polarimeter can simplify the configuration of the detection unit as compared with the prior art in which light-receiving elements are arranged for each of a plurality of polarization-manipulated lights extracted from incident light to detect them in time series. The polarimeter can easily operate using a single commercially available detector, for example, without using an array-type detector that is not easily available in the mid-infrared wavelength band.

[0008] In the polarimeter according to one embodiment, the plurality of polarizers may include a first polarizer that transmits the first portion with the polarization transmission axis in the first orientation, a second polarizer that transmits the second portion of the light with the polarization transmission axis in the second orientation, a third polarizer that transmits the third portion of the light with the polarization transmission axis in the first orientation, and a fourth polarizer that transmits the fourth portion of the light with the polarization transmission axis in the third orientation.

[0009] Thereby, the polarimeter can extract four polarization-manipulated lights with one component. For example, the polarimeter can extract four polarization-manipulated lights respectively having powers P 45°,λ / 4 、P 90° 、P 45° 、P 0° from the light to be measured. The polarimeter facilitates miniaturization or weight reduction by arranging a plurality of polarizers together in a polarizer array.

[0010] In a polarimeter according to an embodiment, the plurality of mirrors may include four MEMS mirrors that reflect the polarization operation light transmitted through the four polarizers respectively. Thereby, the polarimeter can also deflect each polarization operation light toward a single detection unit at the reflection unit. The polarimeter can also collectively make a plurality of polarization operation lights incident on a single detection unit without using a driving mechanism such as a motor. Therefore, the polarimeter facilitates miniaturization or weight reduction as compared with the prior art that uses a driving mechanism such as a motor.

[0011] In a polarimeter according to an embodiment, the optical element may be disposed adjacent to the wave plate and further include a transmission part that transmits the other part without operating the polarization state. Thereby, the polarimeter can transmit the other part of the light through the transmission part of the optical element without the wave plate acting optically. Therefore, the polarimeter can easily extract a plurality of polarization operation lights from the light to be measured. For example, the polarimeter can easily extract four polarization operation lights each having powers P 45°,λ / 4 、P 90° 、P 45° 、P 0° from the light to be measured.

[0012] In a polarimeter according to an embodiment, the control unit may associate different frequencies of the driving signals with the polarization operation lights that have passed through the polarizer array respectively, and separate the detection signals according to the frequencies. Thereby, the polarimeter can extract the detection signals corresponding to each polarization operation light from the frequency-multiplexed detection signals with a high signal-to-noise ratio. For example, the polarimeter can extract the detection signals with a high signal-to-noise ratio by using lock-in detection.

[0013] In a polarimeter according to an embodiment, the control unit may calculate Stokes parameters based on the detection signals separated for each polarization operation light, and calculate polarization parameters as the polarization information based on the Stokes parameters. Thereby, the polarimeter can calculate polarization information including polarization parameters with high precision. For example, the polarimeter uses lock-in detection to measure power P 45°,λ / 4, P 90° , P 45° , P 0° Each of these can be measured with high precision, and Stokes parameters and other polarization information can be calculated with high precision. The polarimeter can detect multiple polarization-controlled light in parallel in time, and compared to conventional techniques that detect each polarization-controlled light at different timings using time-division multiplexing, it can acquire Stokes parameters and other polarization information more quickly.

[0014] In one embodiment, the polarimeter further comprises a spectral section positioned on the incident side of the light from the optical element, which spectrally separates the light by wavelength and guides it to the optical element, and may comprise sets of the optical element, the polarizer array, and the reflecting section for each wavelength.

[0015] This allows the polarimeter to acquire Stokes parameters for each wavelength of light spectrally separated by the spectrometer and calculate polarization parameters for light of a target having a broad wavelength range. The polarimeter can easily acquire polarization information for each wavelength of light spectrally separated by the spectrometer.

[0016] In one embodiment of the polarimeter, the plurality of mirrors may be driven simultaneously for each wavelength. This allows the polarimeter to associate different frequency drive signals for each combination of wavelength type and polarization operation type of light spectrally separated by the spectrometer, enabling the detection of multiple polarization-operated lights for each wavelength and in parallel in time. The polarimeter can simultaneously detect multiple polarization-operated lights for all wavelengths. Therefore, the polarimeter can acquire polarization information more quickly compared to cases where multiple polarization-operated lights are detected for each wavelength at different timings using time-division multiplexing.

[0017] In one embodiment of the polarimeter, the plurality of mirrors may be driven at different timings for each wavelength. This allows the polarimeter to detect multiple polarization-controlled lights with a high signal-to-noise ratio for each wavelength of light spectrally separated by the spectrometer, even when there is a limit to the number of drive signal frequencies that can be associated with the mirrors of the reflective section. Therefore, the polarimeter can acquire polarization information with greater accuracy for each wavelength of light spectrally separated by the spectrometer.

[0018] Some embodiments of the measuring device include a light source unit that irradiates light onto an object to be measured, and one of the above polarimeters into which the light based on the irradiated light onto the object to be measured is incident. The control unit evaluates the quality of the object to be measured based on the calculated polarization information. As a result, the measuring device can evaluate the quality related to the polarization characteristics of the object to be measured by, for example, measuring the change in the polarization parameters of the light from the object to be measured in response to the irradiated light from the light source unit and analyzing the response of the object to polarization. [Effects of the Invention]

[0019] According to this disclosure, it is possible to provide a polarimeter and measuring device in which the configuration of the detection unit is simplified even when detecting multiple polarization-controlled lights in parallel in time. [Brief explanation of the drawing]

[0020] [Figure 1] This is a schematic diagram showing an example of the configuration of a polarimeter according to the first embodiment of this disclosure. [Figure 2] This is a block diagram showing an example of the configuration of a polarimeter according to the first embodiment of this disclosure. [Figure 3] This is a schematic diagram showing an example of the configuration of a polarimeter according to the second embodiment of this disclosure. [Figure 4] Figure 3 is a schematic diagram illustrating the first example of the operation of the polarimeter. [Figure 5] This is the first schematic diagram illustrating a second example of the operation of the polarimeter shown in Figure 3. [Figure 6]This is a second schematic diagram illustrating a second example of the operation of the polarimeter shown in Figure 3. [Figure 7] This is a schematic diagram showing a first example of the configuration of a measuring device having a polarimeter according to the third embodiment of this disclosure. [Figure 8] This is a schematic diagram showing a second example of the configuration of a measuring device having a polarimeter according to the third embodiment of this disclosure. [Figure 9] This is a schematic diagram showing an example of the configuration of a conventional polarimeter. [Modes for carrying out the invention]

[0021] This section provides a more detailed explanation of the background and problems of conventional technologies.

[0022] Figure 9 is a schematic diagram showing an example of the configuration of a conventional polarimeter 200. The conventional polarimeter 200 includes a light beam splitter 201, a polarizing beam splitter 202, a polarizer 203, a quarter-wave plate 204, and a light-receiving element 205.

[0023] The polarimeter 200 splits the incident light, which has been split into two at an appropriate power ratio by the first light beam splitter 201, into two reflected light, for example, 50:50, by the second light beam splitter 201. The polarimeter 200 then splits the reflected light from the second light beam splitter 201 into polarizations, for example, 0° transmission axis orientation and 90° transmission axis orientation, by the polarizing beam splitter 202, and directs each of them into separate photodetectors 205. The power of the light measured using the two photodetectors 205 is then measured by P 0° and P 90° Let's assume that.

[0024] The polarimeter 200 directs the transmitted light from the second optical beam splitter 201 into the third optical beam splitter 201, splitting it into two beams, for example, at a 50:50 ratio. The polarimeter 200 then sequentially transmits the reflected light from the third optical beam splitter 201 through a quarter-wave plate 204 and a polarizer 203 with a transmission axis orientation of, for example, 45°, and directs the transmitted light into individual photodetectors 205. The power of the light measured using the photodetectors 205 is then measured by P 45°,λ / 4Let's assume that.

[0025] The polarimeter 200 transmits the light transmitted through the third light beam splitter 201 to a polarizer 203 with a transmission axis orientation of, for example, 45°, and then directs the transmitted light into individual photodetectors 205. The power of the light measured using the photodetectors 205 is then converted to P 45° Let's assume that.

[0026] The polarimeter 200 measures the power of four polarization-controlled beams extracted from the incident light. 0° , P 90° , P 45°,λ / 4 , P 45° It is also possible to calculate Stokes parameters from this data, and polarization analysis is performed based on the calculated Stokes parameters.

[0027] However, the polarimeter 200 uses a large number of individual elements in each optical component and each light-receiving element 205, which increases the number of parts and complicates the device.

[0028] The polarization analysis device described in Patent Document 1 comprises a polarizer array 401, a quarter-wave plate 701, and a photodetector array 502. The polarization analysis device uses the power P of four polarization-manipulating beams extracted from incident light. 0° , P 90° , P 45°,λ / 4 , P 45° It is identical to the polarimeter 200 in that it calculates the Stokes parameters from the polarimeter. On the other hand, this polarization analysis device has a polarizer array 401 that integrates three types of four polarizers using photonic crystal technology, which significantly reduces the number of parts and the complexity of the part arrangement compared to the polarimeter 200.

[0029] However, the polarization analysis device described in Patent Document 1 uses a detector including an array of photodetectors as the detection unit. In this polarization analysis device, a photodetector is arranged for each of the multiple polarization-modified light beams extracted from the incident light in parallel in time. As a result, the configuration of the detection unit was complicated.

[0030] For example, array-type detectors are generally not readily available in the mid-infrared wavelength range. The price of array-type detectors is also often higher than that of the visible to near-infrared wavelength range. In addition, the detection performance of detectors in the mid-infrared wavelength range is generally inferior to that of the visible to near-infrared wavelength range. Furthermore, it is not easy to perform high-precision measurements with low-power incident light in the mid-infrared wavelength range.

[0031] This disclosure aims to provide a polarimeter and measuring device that simplifies the configuration of the detection unit even when detecting multiple polarization-controlled lights in parallel in time, in order to solve the problems described above. In addition, this disclosure also aims to provide a polarimeter and measuring device that enables high-precision calculation of polarization parameters, which will be described later. Below, one embodiment of this disclosure will be mainly described with reference to the attached drawings.

[0032] (First Embodiment) Figure 1 is a schematic diagram showing an example of the configuration of a polarimeter 1 according to the first embodiment of the present disclosure. The polarimeter 1 has, in order from the side into which the light L to be measured is incident, an incident optical system 10, an optical element 20, a polarizer array 30, a reflector 40, a focusing optical system 50, and a single detection unit 60.

[0033] The incident optical system 10 has, for example, at least one optical element. The optical element includes lenses and mirrors. The incident optical system 10, as an example, has a first lens 11 that optically acts on the light L of the object to be measured that is incident on the polarimeter 1, and a second lens 12 that optically acts on the light L that has passed through the first lens 11. The incident optical system 10 shapes the beam shape of the light L into a predetermined shape that spreads in one direction, for example. With the beam shape of the light L shaped into the predetermined shape, the incident optical system 10 propagates the light L toward the optical element 20.

[0034] The optical element 20 transmits the light L that has passed through the incident optical system 10 and propagates it toward the polarizer array 30. The optical element 20 includes a waveplate 21 upon which a first portion L1 of the light L to be measured is incident. The optical element 20 further includes a transmission portion 22 positioned adjacent to the waveplate 21, which transmits the other portion of the light L without manipulating its polarization state. In this disclosure, “other portion” includes, for example, a second portion L2, a third portion L3, and a fourth portion L4 of the light L to be measured.

[0035] The waveplate 21 includes, for example, a quarter-waveplate. The transmission portion 22 may be, for example, an opening where the medium is air, or a transmission member that has little effect on the polarization state of the light L. The optical element 20, for example, places the waveplate 21 in an area of ​​1 / 4 and the transmission portion 22 in an area of ​​3 / 4 along one direction in which the beam shape of the light L is widened by the incident optical system 10.

[0036] The polarizer array 30 transmits the light L that has passed through the optical element 20 and propagates it toward the reflecting section 40. The polarizer array 30 includes a plurality of polarizers that receive the first portion L1 of the light L that has passed through the waveplate 21 of the optical element 20 and the other portion of the light L that has not passed through the waveplate 21, and have different polarization transmission axes in at least three directions. The polarizer array 30 extracts the linear polarization component in a specific direction along the polarization transmission axis of each polarizer.

[0037] The polarizer array 30 arranges multiple polarizers, each having polarization transmission axes of 45°, 90°, 45°, and 0°, in a straight line with equal area along one direction in which the beam shape of light L is broadened by the incident optical system 10. The polarizer array 30 may have a structure in which multiple polarizers having four polarization transmission axes of three types are joined at their sides, or a structure in which multiple polarizers are fixed in parallel to a retaining material that serves as a frame, or a structure in which multiple polarizers are fabricated on a single substrate using photonic crystal technology.

[0038] The polarizer array 30 includes, for example, a first polarizer 31, a second polarizer 32, a third polarizer 33, and a fourth polarizer 34, in order along one direction in which the beam shape of light L is broadened by the incident optical system 10. The first polarizer 31 transmits the first portion L1 of light L with a polarization transmission axis of a first direction. The polarization transmission axis of the first direction is, for example, a 45° polarization transmission axis. The second polarizer 32 transmits the second portion L2 of light L with a polarization transmission axis of a second direction. The polarization transmission axis of the second direction is, for example, a 90° polarization transmission axis. The third polarizer 33 transmits the third portion L3 of light L with a polarization transmission axis of a first direction. The fourth polarizer 34 transmits the fourth portion L4 of light L with a polarization transmission axis of a third direction. The polarization transmission axis of the third direction is, for example, a 0° polarization transmission axis.

[0039] The reflecting section 40 reflects the polarization-controlled light that has passed through the polarizer array 30 and propagates it toward the focusing optical system 50. The reflecting section 40 includes at least four groups of rectangular mirrors, for example, arranged in a straight line. The multiple mirrors of the reflecting section 40 are arranged in four areas with equal area in a straight line along one direction in which the beam shape of the light L is widened by the incident optical system 10.

[0040] The multiple mirrors of the reflecting section 40 operate independently of each other with drive signals associated with the polarization-controlled light that has passed through the polarizer array 30. The reflecting section 40 includes a device capable of deflecting different parts of the light L by applying drive signals independently to each mirror from, for example, the control unit 74 (described later). The reflecting section 40 can operate at various frequencies and phases for each mirror. The reflecting section 40 includes, for example, a capacitive MEMS structure device. Each of the multiple mirrors of the reflecting section 40 only needs to have at least one axis of rotation.

[0041] The multiple mirrors of the reflecting section 40 include, for example, four MEMS mirrors that reflect the polarization-controlled light transmitted through each of the four polarizers of the polarizer array 30. The four MEMS mirrors of the reflecting section 40 include, for example, a first mirror 41, a second mirror 42, a third mirror 43, and a fourth mirror 44 in order along one direction in which the beam shape of the light L is widened by the incident optical system 10. The first portion L1 of the light L is incident on the first mirror 41. The second portion L2 of the light L is incident on the second mirror 42. The third portion L3 of the light L is incident on the third mirror 43. The fourth portion L4 of the light L is incident on the fourth mirror 44.

[0042] For example, the first mirror 41 operates independently with a first drive signal of a first frequency associated with the first portion L1 of the light L that has passed through the polarizer array 30. The second mirror 42 operates independently with a second drive signal of a second frequency associated with the second portion L2 of the light L that has passed through the polarizer array 30. The third mirror 43 operates independently with a third drive signal of a third frequency associated with the third portion L3 of the light L that has passed through the polarizer array 30. The fourth mirror 44 operates independently with a fourth drive signal of a fourth frequency associated with the fourth portion L4 of the light L that has passed through the polarizer array 30. The first, second, third, and fourth frequencies may all be different values ​​from each other.

[0043] Each MEMS mirror included in the reflector 40 operates under the drive of a control unit 74, described later, based on a corresponding drive signal. Each MEMS mirror is driven by the control unit 74, described later, with drive signals having different frequencies from each other. At this time, the drive signals for driving each MEMS mirror by the control unit 74 may or may not be synchronized with each other. For example, each MEMS mirror maintains a deflection position by tilting at a predetermined angle when the level of the drive signal as a square wave is High. Each MEMS mirror maintains a standby position where the tilt is at a reference angle when the level of the drive signal as a square wave is Low.

[0044] Each MEMS mirror transitions between a standby position and a deflected position in accordance with the rising and falling edges of the drive signal, which is a rectangular wave. When each MEMS mirror maintains the deflected position with a drive signal level of High, for example, it directs the corresponding portion of light L into the detection unit 60 via the focusing optical system 50. When each MEMS mirror maintains the standby position with a drive signal level of Low, for example, it propagates the corresponding portion of light L to a position different from the detection unit 60 via the focusing optical system 50. That is, when each MEMS mirror maintains the standby position with a drive signal level of Low, it does not direct the corresponding portion of light L into the detection unit 60. The MEMS mirror is not limited to the above, and the relationship between the deflected position and the standby position may be reversed. That is, when each MEMS mirror maintains the deflected position with a drive signal level of High, it does not need to direct the corresponding portion of light L into the detection unit 60.

[0045] The focusing optical system 50 has, for example, at least one optical element. The optical element includes lenses and mirrors. The focusing optical system 50 has, as an example, a focusing lens that optically acts on the light L reflected by the reflecting section 40. The focusing optical system 50 focuses the light L reflected by the reflecting section 40 to facilitate its incidence into the detection section 60. Depending on the angle of each MEMS mirror included in the reflecting section 40, the focusing optical system 50 propagates the corresponding portion of the light L toward the detection section 60 or a position different from the detection section 60.

[0046] A single detection unit 60 detects light L reflected by the reflecting unit 40. The detection unit 60 detects the corresponding portion of light L via the focusing optical system 50, depending on the angle of each MEMS mirror included in the reflecting unit 40. For example, the detection unit 60 detects the corresponding portion of the light L to be measured that was reflected by a MEMS mirror in a deflected position among the multiple MEMS mirrors of the reflecting unit 40. The detection unit 60 includes any detector capable of detecting light L and outputting a detection signal having a predetermined signal intensity. The detector includes a light-receiving element such as a photodiode. The wavelength band of the detector matches the wavelength band of the light L to be measured.

[0047] The light L to be measured, incident on the polarimeter 1, is efficiently guided by the incident optical system 10 to the subsequent optical element 20. Of the light L that has passed through the optical element 20, the first portion L1 of the light L that has passed through the waveplate 21 passes through the first polarizer 31 of the polarizer array 30 with a transmission axis orientation of 45°. The remaining portion of the light L that has passed through the transmission section 22 passes through the second polarizer 32, third polarizer 33, and fourth polarizer 34 of the polarizer array 30 with transmission axis orientations of 90°, 45°, and 0°, respectively. The four-branched light L, whose polarization is controlled by the polarizer array 30, is guided to correspond to the four MEMS mirrors of the reflection section 40. The four-branched light L is deflected so that it either incidents on the detection surface of a single detection section 60 via the focusing optical system 50, or does not incident on it, by controlling the angle of each MEMS mirror by the control unit 74, which will be described later.

[0048] For example, of the light L transmitted through the incident optical system 10, the first portion L1 is guided in the following order: the waveplate 21 of the optical element 20, the first polarizer 31 of the polarizer array 30, the first mirror 41 of the reflecting section 40, and the focusing optical system 50. The second portion L2 is guided in the following order: the transmission section 22 of the optical element 20, the second polarizer 32 of the polarizer array 30, the second mirror 42 of the reflecting section 40, and the focusing optical system 50. The third portion L3 is guided in the following order: the transmission section 22 of the optical element 20, the third polarizer 33 of the polarizer array 30, the third mirror 43 of the reflecting section 40, and the focusing optical system 50. The fourth portion L4 is guided in the following order: the transmission section 22 of the optical element 20, the fourth polarizer 34 of the polarizer array 30, the fourth mirror 44 of the reflecting section 40, and the focusing optical system 50.

[0049] Figure 2 is a block diagram showing an example of the configuration of a polarimeter 1 according to the first embodiment of the present disclosure. In addition to the optical system components shown in Figure 1, the polarimeter 1 further includes a processing unit 71, an output unit 72, a storage unit 73, and a control unit 74. In Figure 2, of the optical system components shown in Figure 1, only the reflective unit 40, which is electrically controlled by the control unit 74, and the detection unit 60, which outputs an electrical detection signal to the control unit 74, are shown together.

[0050] The processing unit 71 includes an optional circuit for extracting a predetermined frequency from among multiple detection signals from the detection unit 60, whose signal intensity is modulated at multiple frequencies by the repeated operation of the standby and deflection positions of the multiple MEMS mirrors of the reflecting unit 40. The circuit includes, for example, a circuit for lock-in detection. The processing unit 71 receives a reference signal of the same frequency synchronized with the drive signal for each MEMS mirror from the control unit 74 and extracts only the detection signal of the frequency corresponding to the reference signal. The processing unit 71 performs lock-in detection using the reference signal input from the control unit 74 and extracts the power P of the four polarization-controlled optics extracted from the light L to be measured. 0° , P 90° , P 45° , P 45°,λ / 4 The detection signal corresponding to each of these is acquired by frequency discrimination.

[0051] The output unit 72 includes one or more output interfaces for outputting information to the user. The output interfaces include a display for visually outputting information as an image and a speaker for audibly outputting information as sound. The display is, for example, an LCD (Liquid Crystal Display) or an organic EL (Electro Luminescence) display. The output unit 72 outputs the data obtained by the operation of the polarimeter 1 visually or audibly. The output unit 72 may be connected to the polarimeter 1 as an external output device instead of being provided in the polarimeter 1. The connection method includes any method such as USB (Universal Serial Bus), HDMI (High-Definition Multimedia Interface), and Bluetooth (Bluetooth).

[0052] The storage unit 73 includes any storage module, such as an HDD (Hard Disk Drive), SSD (Solid State Drive), EEPROM (Electrically Erasable Programmable Read-Only Memory), ROM (Read-Only Memory), and RAM (Random Access Memory). The storage unit 73 functions, for example, as main memory, auxiliary memory, or cache memory. The storage unit 73 is not limited to those built into the polarimeter 1, and may also include external storage modules connected by digital input / output ports such as USB.

[0053] The memory unit 73 stores any data or information used in the operation of the polarimeter 1. For example, the memory unit 73 stores system programs and application programs. The memory unit 73 also stores any data or information obtained through the operation of the polarimeter 1. For example, the memory unit 73 stores information on the detection signal of light L detected by the detection unit 60, information on the Stokes parameters calculated by the control unit 74 based on the detection signal (described later), and various other information calculated by the control unit 74 based on the Stokes parameters (described later).

[0054] The control unit 74 includes one or more processors. In the first embodiment, the "processor" is a general-purpose processor or a dedicated processor specialized for a specific process, but is not limited to these. The control unit 74 performs necessary calculation processing based on each detection signal obtained by the processing unit 71 using a reference signal corresponding to the drive signal output from the control unit 74 toward the reflection unit 40 to discriminate its frequency.

[0055] The control unit 74 may further include any circuit that outputs signals that will be the basis for the drive signals and the reference signals. The circuit may include, for example, a signal generator that outputs a square wave having a predetermined frequency and phase. The drive signals output from the control unit 74 to the reflecting unit 40 to drive each MEMS mirror in the reflecting unit 40 are generated using the signal generator of the control unit 74. The reference signals output from the control unit 74 to the processing unit 71 are generated using the signal generator of the control unit 74. The signal generator sets each frequency such that the number of frequencies in the drive signals matches the number of polarization control rays of light L associated with the multiple MEMS mirrors in the reflecting unit 40. For example, if there are four polarization control rays, the number of frequencies will also be four.

[0056] The control unit 74 separates the detection signal from the detection unit 60 for each polarization-operated light according to the drive signal and calculates the polarization information of the light L to be measured. In this disclosure, "polarization information" includes information on the Stokes parameters themselves and various information calculated based on said Stokes parameters. "Various information" includes information on the polarization parameters and information on the polarization state on the Poincaré sphere. "Polarization parameters" include azimuthal angle, elliptic angle ratio, degree of polarization, degree of linear polarization, and degree of circular polarization.

[0057] Stokes parameters are, for example, the power P of four polarization-controlled beams extracted from the light L being measured. 0° , P 90° , P 45° , P 45°,λ / 4 It is defined using the following formulas. For example, the Stokes parameter S0 is the sum of the powers between the polarization components that are mutually orthogonal at 0° and 90°, as shown in Equation 1. The Stokes parameter S1 is the difference in powers between the polarization components that are mutually orthogonal at 0° and 90°, as shown in Equation 2. The Stokes parameter S2 is the difference between S0 and twice the power of the 45° polarization component, as shown in Equation 3. The Stokes parameter S3 is the difference between S0 and twice the power of the 45° polarization component of light L that has passed through a quarter-wave plate, as shown in Equation 4.

[0058]

number

[0059] Polarization parameters are calculated based on Stokes parameters using the following equations 5 through 9. Of the polarization parameters, the orientation angle is calculated using equation 5. The ellipticity angle is calculated using equation 6. The degree of polarization (DOP) is calculated using equation 7. The degree of linear polarization (DOLP) is calculated using equation 8. The degree of circular polarization (DOCP) is calculated using equation 9.

[0060]

number

[0061] The control unit 74 applies a drive signal of a square wave of a different frequency to each of the multiple MEMS mirrors of the reflecting section 40, deflecting the corresponding portion of the light L. As a result, the control unit 74 controls the power P 0° , P 90° , P 45° , P 45°,λ / 4 Polarization-controlled light extracted from the light L is deflected at different frequencies and incident on the detection surface of a single detection unit 60. The detection signals output from the single detection unit 60 are amplitude-modulated at different frequencies and frequency multiplexed. The control unit 74 performs lock-in detection or synchronous detection using the processing unit 71, thereby generating power P 0° , P 90° , P 45° , P 45°,λ / 4 The corresponding detection signals are electrically isolated. The control unit 74 associates the frequencies of the different drive signals with the light L that has passed through the polarizer array 30, and separates the detection signals according to those frequencies.

[0062] The control unit 74 controls the power of the light L, which has been branched into four optical paths by the optical element 20 and the polarizer array 30, by P 0° , P90° , P 45° , P 45°,λ / 4 The Stokes parameters are calculated using equations 1 to 4. The control unit 74 calculates the Stokes parameters based on the detection signals separated for each polarization operation light. Based on the calculated Stokes parameters, the control unit 74 calculates the polarization parameters as polarization information using equations 5 to 9. The control unit 74 may visually display the polarization information, including the calculated Stokes parameters and polarization parameters, as numerical values ​​and graphs, for example, using the display of the output unit 72.

[0063] According to the polarimeter 1 of the first embodiment described above, the configuration of the detection unit 60 is simplified even when detecting multiple polarization-modified light in parallel in time. The polarimeter 1 has an optical element 20 including a waveplate 21 into which a first portion L1 of the light L to be measured is incident, and a polarizer array 30 including a plurality of polarizers having polarization transmission axes that are different from each other in at least three directions, so that multiple polarization-modified light can be extracted from the light L to be measured. The polarimeter 1 has a reflecting unit 40 including a plurality of mirrors that operate independently of each other with drive signals associated with each polarization-modified light that has passed through the polarizer array 30, so that the mirrors of the reflecting unit 40 can be operated independently for each polarization-modified light of the light L, and each polarization-modified light extracted from the light L can be guided to a single detection unit 60.

[0064] Therefore, the polarimeter 1 can simplify the configuration of the detection unit 60 compared to conventional technology in which a photodetector is arranged for each of the multiple polarization-modified light streams extracted from the incident light in parallel in time. The polarimeter 1 can be easily operated using a single commercially available detector, for example, without using an array-type detector that is not readily available in the mid-infrared wavelength band.

[0065] The polarimeter 1 separates the detection signal from the detection unit 60 for each type of light whose polarization has been manipulated according to the drive signal, and calculates the polarization information of the light L. This allows the polarimeter 1 to extract the detection signal corresponding to each polarized light from the frequency-multiplexed detection signal with a high signal-to-noise ratio (S / N ratio). For example, the polarimeter 1 can extract the detection signal with a high S / N ratio by using lock-in detection. Therefore, the polarimeter 1 can calculate polarization information, including polarization parameters, with high accuracy. Although using a single detection unit 60, the polarimeter 1 can detect multiple polarized lights in parallel in time, enabling faster acquisition of polarization information compared to conventional techniques that detect each polarized light at different timings using time-division multiplexing.

[0066] The polarizer array 30 includes a first polarizer 31 that transmits a first portion L1 along the first polarization transmission axis, a second polarizer 32 that transmits a second portion L2 along the second polarization transmission axis, a third polarizer 33 that transmits a third portion L3 along the first polarization transmission axis, and a fourth polarizer 34 that transmits a fourth portion L4 along the third polarization transmission axis. This allows the polarimeter 1 to extract four polarization-controlled light from light L using a single component. For example, the polarimeter 1 uses power P 45°,λ / 4 , P 90° , P 45° , P 0° Four polarized light beams, each possessing a specific polarity, can be extracted from the light beam L being measured. The polarimeter 1 facilitates miniaturization or weight reduction by arranging multiple polarizers together in a polarizer array 30.

[0067] The multiple mirrors in the reflective section 40 include four MEMS mirrors that reflect the polarization-controlled light that has passed through each of the four polarizers. This allows the polarimeter 1 to deflect each polarization-controlled light of the light L towards a single detection unit 60 using the reflective section 40. The polarimeter 1 can also direct multiple polarization-controlled light of the light L into a single detection unit 60 without using a drive mechanism such as a motor. Therefore, the polarimeter 1 can be made smaller or lighter compared to conventional technology that uses a drive mechanism such as a motor.

[0068] The optical element 20 is positioned adjacent to the waveplate 21 and further includes a transmitting portion 22 that transmits other parts of the light L without manipulating its polarization state. This allows the polarimeter 1 to transmit other parts of the light L through the transmitting portion 22 of the optical element 20 without the waveplate 21 acting optically. Therefore, the polarimeter 1 can easily extract multiple polarization-modified light from the light L being measured. For example, the polarimeter 1 uses power P 45°,λ / 4 , P 90° , P 45° , P 0° Four polarized light beams, each possessing a specific characteristic, can be easily extracted from the light beam L being measured.

[0069] The polarimeter 1 associates the frequencies of different drive signals with the polarization-controlled light that has passed through the polarizer array 30, and separates the detection signals according to those frequencies. This allows the polarimeter 1 to extract the detection signal corresponding to each polarization-controlled light from the frequency-multiplexed detection signal with a high signal-to-noise ratio. For example, the polarimeter 1 can extract the detection signal with a high signal-to-noise ratio by using lock-in detection.

[0070] The polarimeter 1 calculates Stokes parameters based on detection signals separated for each polarization-controlled light, and calculates polarization parameters as polarization information based on the Stokes parameters. This allows the polarimeter 1 to calculate polarization information, including polarization parameters, with high accuracy. For example, the polarimeter 1 uses lock-in detection to measure power P 45°,λ / 4 , P 90° , P 45° , P 0° Each of these can be measured with high precision, and Stokes parameters and other polarization information can be calculated with high precision. Polarimeter 1 can detect multiple polarization-controlled light in parallel in time, and compared to conventional techniques that detect each polarization-controlled light at different timings using time-division multiplexing, it is possible to acquire Stokes parameters and other polarization information more quickly.

[0071] In the above embodiment, the waveplate 21 was described as including a quarter-wave plate, but is not limited thereto. The waveplate 21 may include any other phase difference plate, such as a half-wave plate.

[0072] In the above embodiment, the polarizers of the polarizer array 30 were described as including, but are not limited to, a first polarizer 31, a second polarizer 32, a third polarizer 33, and a fourth polarizer 34. The polarizers of the polarizer array 30 may consist of any number other than four, as long as they have different polarization transmission axes in at least three directions. The three directions of the polarizers of the polarizer array 30 were described as 0°, 45°, and 90°, but are not limited to these. The three directions of the polarizers of the polarizer array 30 may consist of other angles.

[0073] In the above embodiment, the plurality of mirrors in the reflecting section 40 was described as including four MEMS mirrors that reflect the polarization-controlled light transmitted through each of the four polarizers, but is not limited to this. The plurality of mirrors in the reflecting section 40 may consist of a number other than four. Each of the plurality of mirrors in the reflecting section 40 may include other mirrors having a mechanism different from that of the MEMS mirrors.

[0074] In the above embodiment, the optical element 20 was described as further including a transmitting portion 22 positioned adjacent to the waveplate 21 that transmits other portions without manipulating the polarization state, but it is not limited to this. The optical element 20 may have only the waveplate 21 without the transmitting portion 22. In this case, the other portions of the light L, including the second portion L2, the third portion L3, and the fourth portion L4, may pass through a region adjacent to the waveplate 21 of the optical element 20, which is a free space region where no part of the optical element 20 exists.

[0075] In the above embodiment, the control unit 74 of the polarimeter 1 was described as associating the frequencies of different drive signals with the polarization-operated light that has passed through the polarizer array 30, and separating the detection signal according to the frequency, but is not limited to this. The control unit 74 may associate drive signals having at least one of different frequencies and phases with the polarization-operated light that has passed through the polarizer array 30, and separate the detection signal according to the frequency or phase.

[0076] For example, the control unit 74 may apply a drive signal to each of the multiple MEMS mirrors of the reflecting unit 40 with a waveform in which at least one of the frequency and phase is different from each other. In this case, the control unit 74 may output to the processing unit 71 a reference signal corresponding to the drive signal applied to each of the multiple MEMS mirrors, with a waveform in which at least one of the frequency and phase is different from each other. Accordingly, the polarimeter 1 is not limited to lock-in detection, but may perform other detection processes such as phase detection.

[0077] In the above embodiment, the control unit 74 of the polarimeter 1 was described as calculating Stokes parameters based on detection signals separated for each polarization-controlled light, and calculating polarization parameters as polarization information based on the Stokes parameters, but it is not limited to this. For example, the polarimeter 1 may only measure the power of the polarization-controlled light of light L, and not perform the calculation processing of Stokes parameters and polarization parameters. In this case, the polarimeter 1 may output the measurement result of the power of the polarization-controlled light of light L to an external device that performs the calculation processing of Stokes parameters and polarization parameters.

[0078] (Second Embodiment) Figure 3 is a schematic diagram showing an example of the configuration of the polarimeter 1 according to the second embodiment of this disclosure. The configuration and function of the polarimeter 1 according to the second embodiment will be mainly described with reference to Figure 3. The polarimeter 1 according to the second embodiment differs from the first embodiment in that it further has a spectroscopic unit 80.

[0079] Other configurations, functions, effects, and modifications are the same as in the first embodiment, and the corresponding descriptions also apply to the polarimeter 1 according to the second embodiment. In the following, components the same as in the first embodiment are denoted by the same reference numerals, and their descriptions are omitted. The differences from the first embodiment will be mainly described.

[0080] The polarimeter 1 according to the second embodiment further includes a spectral section 80 positioned on the incident side of the optical element 20, which spectrally separates the light L according to its wavelength and guides it to the optical element 20. The spectral section 80 is positioned between the incident optical system 10 and the optical element 20. The spectral section 80 includes, for example, optical elements such as a variable filter and a diffraction grating.

[0081] The polarimeter 1, having a spectrometer 80, can acquire Stokes parameters for each wavelength of light L spectrally separated by the spectrometer 80 for a light target L having a broad wavelength range, and calculate polarization parameters. The polarimeter 1 can easily acquire polarization information for each wavelength of light L spectrally separated by the spectrometer 80.

[0082] Figure 4 is a schematic diagram illustrating the first example of the operation of the polarimeter 1 in Figure 3. Figure 5 is a first schematic diagram illustrating the second example of the operation of the polarimeter 1 in Figure 3. Figure 6 is a second schematic diagram illustrating the second example of the operation of the polarimeter 1 in Figure 3. In Figures 4 to 6, the region corresponding to the spectroscopic unit 80 shows the wavelengths λ1, λ2, ..., and λ of the light L spectrally separated by the spectroscopic unit 80. n The region corresponding to the reflecting section 40 shows the frequencies f1, f2, ..., and f of the drive signals associated with each of the multiple MEMS mirrors of the reflecting section 40. 4n This is shown.

[0083] As conceptually shown in Figures 4 to 6, the optical element 20 has a configuration in which multiple combinations of a wave plate 21 located in an area of ​​1 / 4 of the area and a transmission portion 22 located in an area of ​​3 / 4 are arranged linearly for each wavelength. The polarizer array 30 has a configuration in which multiple combinations of polarizers, each having polarization transmission axes of 45°, 90°, 45°, and 0° respectively, arranged in equal areas are arranged linearly for each wavelength. The reflective portion 40 has a configuration in which multiple combinations of MEMS mirrors are arranged linearly for each wavelength.

[0084] As described above, the polarimeter 1 has a set of optical element 20, polarizer array 30, and reflector 40 for each wavelength. Each of the multiple wave plates 21 of the optical element 20 may have optimal wavelength characteristics corresponding to the wavelength of light L spectrally separated by the spectroscopic unit 80. Each of the multiple combinations of the first polarizer 31, second polarizer 32, third polarizer 33, and fourth polarizer 34 of the polarizer array 30 may have optimal wavelength characteristics corresponding to the wavelength of light L spectrally separated by the spectroscopic unit 80. Each of the multiple combinations of the four MEMS mirrors of the reflector 40 may have optimal wavelength characteristics corresponding to the wavelength of light L spectrally separated by the spectroscopic unit 80.

[0085] As shown in the first example in Figure 4, the multiple mirrors of the reflecting section 40 may be driven simultaneously for each wavelength of light L spectrally separated by the spectroscopic section 80. For example, the multiple mirrors of the reflecting section 40 may be driven simultaneously at different frequencies for each combination of wavelength type and polarization operation type of light L spectrally separated by the spectroscopic section 80. The control unit 74 of the polarimeter 1 may drive each of the multiple MEMS mirrors of the reflecting section 40 with drive signals of appropriate frequencies that are all different from each other, thereby deflecting each polarization operation light of the light L and guiding it to a single detection unit 60. Similar to the first embodiment, the control unit 74 may electrically separate the frequency-multiplexed detection signals for each combination of wavelength type and polarization operation type by lock-in detection or synchronous detection using the processing unit 71.

[0086] As a result, the polarimeter 1 associates different frequency drive signals for each combination of wavelength type and polarization operation type of the light L spectrally separated by the spectrometer 80, enabling it to detect multiple polarization-operated lights for each wavelength and in parallel in time. The polarimeter 1 can simultaneously detect multiple polarization-operated lights for all wavelengths. Therefore, the polarimeter 1 can acquire polarization information more quickly compared to cases where multiple polarization-operated lights are detected for each wavelength at different timings using time-division multiplexing.

[0087] As shown in the second example in Figures 5 and 6, the multiple mirrors of the reflecting section 40 may be driven at different timings for each wavelength of light L spectrally separated by the spectroscopic section 80. For example, if there is a limit to the number of drive signal frequencies that can be associated with the MEMS mirrors of the reflecting section 40, the control unit 74 of the polarimeter 1 may associate only four predetermined frequencies with each of the four MEMS mirrors and perform the deflection operation.

[0088] For example, at the first time point shown in Figure 5, the control unit 74 may associate four different frequencies, f1, f2, f3, and f4, with the four MEMS mirrors that reflect light L of wavelength λ1. In this case, the control unit 74 may apply only DC signals to the MEMS mirrors that reflect light L of other wavelengths, and keep the MEMS mirrors stationary at an angle where the light L does not enter a single detection unit 60.

[0089] For example, at the second time point shown in Figure 6, following the first time point, the control unit 74 may associate four different frequencies, f1, f2, f3, and f4, with four MEMS mirrors that reflect light L of a different wavelength λ2 than wavelength λ1. In this case, the control unit 74 may apply only DC signals to the multiple MEMS mirrors that reflect light L of other wavelengths, and keep the MEMS mirrors stationary at an angle where the light L does not enter a single detection unit 60.

[0090] The control unit 74 may sequentially perform the above switching operations for the combination of four MEMS mirrors over all wavelengths of the light L spectrally separated by the spectroscopic unit 80. The control unit 74 may sequentially acquire the frequency-multiplexed detection signal using a single detection unit 60 while switching the combination of multiple MEMS mirrors to which the drive signal is applied. Similar to the first embodiment, the control unit 74 may electrically separate the frequency-multiplexed detection signal for each polarization-operated light by lock-in detection or synchronous detection using the processing unit 71.

[0091] As a result, the polarimeter 1 can detect multiple polarization-controlled light signals with a high signal-to-noise ratio for each wavelength of light L spectrally separated by the spectrometer 80, even when there is a limit to the number of drive signal frequencies that can be associated with the MEMS mirror of the reflecting section 40. Therefore, the polarimeter 1 can acquire polarization information with greater accuracy for each wavelength of light L spectrally separated by the spectrometer 80.

[0092] (Third embodiment) Figure 7 is a schematic diagram showing a first example of the configuration of a measuring device 100 having a polarimeter 1 according to the third embodiment of this disclosure. The configuration and function of the polarimeter 1 and measuring device 100 according to the third embodiment will be mainly described with reference to Figure 7. The polarimeter 1 according to the third embodiment differs from the first and second embodiments in that it is provided in the measuring device 100.

[0093] Other configurations, functions, effects, and variations are the same as in the first and second embodiments, and the corresponding descriptions also apply to the polarimeter 1 according to the third embodiment. In the following, components similar to those in the first and second embodiments are denoted by the same reference numerals, and their descriptions are omitted. The differences from the first and second embodiments will be described in detail.

[0094] The measuring device 100 includes a light source unit 110 that irradiates light toward the object to be measured S, and a polarimeter 1 into which light L based on the irradiated light irradiated toward the object to be measured S is incident. The measuring device 100 has a transmissive configuration in which the light source unit 110 and the polarimeter 1 are arranged on opposite sides of the object to be measured S. In this disclosure, "object to be measured S" includes, for example, optical films, sheets, and semiconductor layers having crystalline orientation.

[0095] The measuring device 100 has a moving mechanism 120 that moves the light source unit 110 and the polarimeter 1 respectively in an intersecting direction D2 that intersects the movement direction D1 of the object to be measured S. For example, with respect to the object to be measured S which is moved inline in the movement direction D1 by a transport device R, the measuring device 100 performs measurements related to the polarization information of light L while the light source unit 110 and the polarimeter 1 move within the range of movement in the intersecting direction D2 by the moving mechanism 120.

[0096] The light source unit 110 includes any light source that irradiates light onto the object S to be measured, which is, for example, an object whose quality related to polarization characteristics is to be evaluated. The light source includes LED (Light Emitting Diode) light sources and LD (Laser Diode) light sources. The irradiated light from the light source may have any perfect polarization, such as linear polarization, circular polarization, and elliptic polarization.

[0097] The polarimeter 1 detects the response of the object to be measured S to polarization by receiving the transmitted light L from the light source unit 110 that irradiates the object to be measured S. The control unit 74 of the polarimeter 1 evaluates the quality of the object to be measured S based on the polarization information of the light L calculated based on the detection signal from a single detection unit 60.

[0098] As described above, the measuring device 100 can evaluate the quality related to the polarization characteristics of the object S by, for example, measuring the change in the polarization parameter of the light L from the object S to be measured in response to the light irradiated from the light source unit 110 and analyzing the response of the object S to the polarization.

[0099] Although it has been explained that such evaluation processing is performed by the control unit 74 of the polarimeter 1, it is not limited to this. The evaluation processing may also be performed by, for example, a calculation unit including a processor provided separately from the control unit 74 of the polarimeter 1 in the measuring device 100. The evaluation processing may also be performed by, for example, another external device different from the measuring device 100. In this case, the measuring device 100 may output the measurement result of the power of the polarization-controlled light L to the other external device.

[0100] Figure 8 is a schematic diagram showing a second example of the configuration of a measuring device 100 having a polarimeter 1 according to the third embodiment of this disclosure. In Figure 7, the measuring device 100 was described as having a transmissive configuration in which the light source unit 110 and the polarimeter 1 are arranged on different sides of the object to be measured S, but is not limited to this. As shown in Figure 8, the measuring device 100 may have a reflective configuration in which the light source unit 110 and the polarimeter 1 are arranged on the same side of the object to be measured S.

[0101] It will be obvious to those skilled in the art that this disclosure can be implemented in other predetermined forms other than the embodiments described above without deviating from its spirit or essential features. Therefore, the prior description is illustrative and not limiting. The scope of the disclosure is defined not by the prior description but by the added claims. Any modifications within their equivalent scope are included therein.

[0102] For example, the shape, pattern, size, arrangement, orientation, type, and number of each component described above are not limited to those shown in the above description and drawings. The shape, pattern, size, arrangement, orientation, type, and number of each component may be configured arbitrarily as long as they can achieve their function. Each component of the polarimeter 1 and measuring device 100 shown is a functional concept. The specific form of each component is not limited to those shown.

[0103] Some embodiments of the present disclosure are described below. However, it should be noted that the embodiments of the present disclosure are not limited to these. [Note 1] An optical element including a waveplate into which the first portion of the light to be measured is incident, A polarizer array comprising a plurality of polarizers having polarization transmission axes different from each other in at least three directions, into which the first portion that has passed through the waveplate and the other portion of the light that has not passed through the waveplate are incident, A reflective section including a plurality of mirrors that operate independently of each other with drive signals associated with the polarization-controlled light that has passed through the polarizer array, A single detection unit for detecting the polarization-controlled light reflected by the reflection unit, A control unit separates the detection signal from the detection unit for each polarization-operated light according to the drive signal and calculates the polarization information of the light, Equipped with, Polarimeter. [Note 2] A polarimeter as described in Appendix 1, The aforementioned plurality of polarizers, A first polarizer that transmits the first portion through the polarization transmission axis in the first orientation, A second polarizer that transmits the second portion of the light in the polarization transmission axis of the second direction, A third polarizer that transmits the third portion of the light along the polarization transmission axis in the first orientation, A fourth polarizer that transmits the fourth portion of the light through the polarization transmission axis in the third direction, including, Polarimeter. [Note 3] The polarimeter described in Appendix 2, The plurality of mirrors includes four MEMS mirrors that reflect the polarization-controlled light that has passed through each of the four polarizers. Polarimeter. [Note 4] A polarimeter described in any one of the appendices 1 to 3, The optical element further includes a transparent portion that is positioned adjacent to the waveplate and transmits light through the other portion without manipulating the polarization state. Polarimeter. [Note 5] A polarimeter described in any one of the appendices 1 to 4, The control unit associates the frequencies of the drive signals, which are different from each other, with the polarization-operated light that has passed through the polarizer array, and separates the detection signals according to the frequencies. Polarimeter. [Note 6] A polarimeter described in any one of the appendices 1 to 5, The control unit calculates Stokes parameters based on the detection signals separated for each polarization-operated light, and calculates polarization parameters as polarization information based on the Stokes parameters. Polarimeter. [Note 7] A polarimeter described in any one of the appendices 1 to 6, The optical element is further provided with a spectral unit positioned on the incident side of the light, which spectrally separates the light according to its wavelength and guides it to the optical element. The optical element, the polarizer array, and the reflective portion are provided in sets for each wavelength. Polarimeter. [Note 8] A polarimeter as described in Appendix 7, The plurality of mirrors are driven simultaneously for each wavelength. Polarimeter. [Note 9] A polarimeter as described in Appendix 7, The plurality of mirrors are driven at different timings for each wavelength. Polarimeter. [Note 10] A light source unit that emits light toward the object to be measured, A polarimeter according to any one of the appendices 1 to 9, into which the light based on the irradiation light irradiated onto the object to be measured is incident, Equipped with, The control unit evaluates the quality of the object to be measured based on the calculated polarization information. Measuring device. [Explanation of Symbols]

[0104] 1. Polarimeter 10 Input optical system 11. First lens 12. Second lens 20 optical elements 21 Wave plate 22 Transparent part 30 polarizer arrays 31. First polarizer 32 Second polarizer 33 Third polarizer 34. Fourth polarizer 40 Reflector 41 First Mirror 42 Second Mirror 43 Third Mirror 44 Fourth Mirror 50 Focusing Optical System 60 Detection unit 71 Processing Unit 72 Output section 73 Memory section 74 Control Unit 80 Spectroscopic section 100 measuring devices 110 Light source section 120 Moving mechanism D1 Movement direction D2 Cross direction L light L1 1st part L2 second part L3 3rd part L4 4th part R Conveyor System S Measured object

Claims

1. An optical element including a waveplate into which the first portion of the light to be measured is incident, A polarizer array comprising a plurality of polarizers having polarization transmission axes that are different from each other in at least three directions, into which the first portion that has passed through the waveplate and the other portion of the light that has not passed through the waveplate are incident, A reflective section including a plurality of mirrors that operate independently of each other with drive signals associated with the polarization-controlled light that has passed through the polarizer array, A single detection unit for detecting the polarization-controlled light reflected by the reflection unit, A control unit separates the detection signal from the detection unit for each polarization-operated light according to the drive signal and calculates the polarization information of the light, Equipped with, Polarimeter.

2. A polarimeter according to claim 1, The aforementioned plurality of polarizers, A first polarizer that transmits the first portion through the polarization transmission axis in the first direction, A second polarizer that transmits the second portion of the light in the polarization transmission axis of the second direction, A third polarizer that transmits the third portion of the light along the polarization transmission axis in the first orientation, A fourth polarizer that transmits the fourth portion of the light through the polarization transmission axis in the third direction, including, Polarimeter.

3. A polarimeter according to claim 2, The plurality of mirrors includes four MEMS mirrors that reflect the polarization-controlled light that has passed through each of the four polarizers. Polarimeter.

4. A polarimeter according to any one of claims 1 to 3, The optical element further includes a transparent portion that is positioned adjacent to the waveplate and transmits light through the other portion without manipulating the polarization state. Polarimeter.

5. A polarimeter according to any one of claims 1 to 3, The control unit associates the frequencies of the drive signals, which are different from each other, with the polarization-operated light that has passed through the polarizer array, and separates the detection signals according to the frequencies. Polarimeter.

6. A polarimeter according to any one of claims 1 to 3, The control unit calculates Stokes parameters based on the detection signals separated for each polarization-operated light, and calculates polarization parameters as polarization information based on the Stokes parameters. Polarimeter.

7. A polarimeter according to any one of claims 1 to 3, The optical element is further provided with a spectral unit positioned on the incident side of the light, which spectrally separates the light according to its wavelength and guides it to the optical element. The optical element, the polarizer array, and the reflective portion are provided in sets for each wavelength. Polarimeter.

8. A polarimeter according to claim 7, The plurality of mirrors are driven simultaneously for each wavelength. Polarimeter.

9. A polarimeter according to claim 7, The plurality of mirrors are driven at different timings for each wavelength. Polarimeter.

10. A light source unit that emits light toward the object to be measured, A polarimeter according to any one of claims 1 to 3, wherein the light based on the irradiation light irradiated onto the object to be measured is incident, Equipped with, The control unit evaluates the quality of the object to be measured based on the calculated polarization information. Measuring device.

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