Analysis program, analysis device, analysis method, and measuring device

Abstract

To provide a technique for estimating birefringence characteristics of a measurement object in more detail than before.SOLUTION: A measuring device comprises: a light source; a linear polarizer disposed on an optical path from the light source to a measurement object; a rotary drive mechanism for configuring the linear polarizer or the measurement object rotatably such that a polarization surface of linear polarization is rotated relatively with respect to the measurement object in a state in which an advance direction of linear polarization passing through the linear polarizer is maintained; a polarization diffraction grating that is disposed on an optical path of light after linear polarization passes the measurement object and generates diffraction light from the light; and a camera for generating an image expressing the measurement object by receiving diffraction light. An analysis program allows a computer to execute processing for acquiring images for each rotational angle of a polarization surface relative to the measurement object, processing for calculating light intensity of diffraction light for each rotational angle on the basis of multiple acquired images, processing for estimating birefringence characteristics on the basis of a shift of light intensity relative to a rotational angle, and processing for outputting birefringence characteristics.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to an analysis program, an analysis device, an analysis method, and a measurement device. [Background technology]

[0002] The crossed Nicols method is a method for measuring the birefringence of a birefringent medium. The crossed Nicols method is described, for example, in JP 2019-100862 A (Patent Document 1) as follows:

[0003] In the crossed Nicol method, a polarizer and an analyzer, which are orthogonal to each other, and a birefringent medium as a measurement object placed between them are rotated relative to each other, and the intensity I of the light transmitted through the polarizer, the measurement object, and the analyzer is measured. out (θ) is measured, and the birefringence Δn of the object to be measured is calculated using the following formula (see paragraph

[0002] ).

[0004]

number

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2019-100862 Summary of the Invention [Problem to be solved by the invention]

[0006] Figure 24 shows the relationship between "θ" and "I out 24 is a diagram showing the relationship between the rotation angle "θ" and the light intensity "I out (θ) is the same, and the resulting image is the same. In this case, there is a limit to the ability to detect the birefringence characteristics of the measurement object, and the birefringence characteristics of the measurement object cannot be estimated in detail. Therefore, there is a need for a technology that can estimate the birefringence characteristics of the measurement object in more detail than before. [Means for solving the problem]

[0007] In one example of the present disclosure, there is provided an analysis program for a measurement object measured by a measurement device. The measurement device includes a light source for irradiating the measurement object with light, a linear polarizer arranged on an optical path from the light source to the measurement object, a rotation drive mechanism for configuring the linear polarizer or the measurement object to be rotatable so that the polarization plane of the linearly polarized light rotates relative to the measurement object while maintaining the direction of propagation of the linearly polarized light passing through the linear polarizer, a polarization diffraction grating arranged on the optical path of the light after the linearly polarized light has passed through the measurement object and for generating diffracted light from the light, and a camera for receiving the diffracted light and generating an image representing the measurement object. The analysis program causes a computer to execute the following processes: acquire the images for each rotation angle of the polarization plane relative to the measurement object; calculate the light intensity of the diffracted light for each rotation angle based on the multiple images acquired in the acquisition process; estimate birefringence characteristics at at least one location of the measurement object based on the change in the light intensity with respect to the rotation angle; and output the characteristics.

[0008] In one example of the present disclosure, the characteristic includes an orientation direction of molecules of the object to be measured.

[0009] In one example of the present disclosure, in the estimation process, the orientation direction is estimated based on at least one of a rotation angle corresponding to the maximum light intensity in the transition and a rotation angle corresponding to the minimum light intensity in the transition.

[0010] In an example of the present disclosure, in the outputting process, an object indicating the orientation direction is superimposed on an image representing the measurement object.

[0011] In one example of the present disclosure, the characteristic further includes an amount of change in the light intensity.

[0012] In one example of the present disclosure, the amount of change is represented by the difference between the maximum light intensity in the transition and the minimum light intensity in the transition.

[0013] In an example of the present disclosure, in the outputting process, an object indicating the amount of change is superimposed on an image representing the measurement object.

[0014] Another example of the present disclosure provides an analysis device for a measurement object measured by a measurement device. The measurement device includes a light source for irradiating the measurement object with light, a linear polarizer arranged on an optical path from the light source to the measurement object, a rotation drive mechanism for configuring the linear polarizer or the measurement object to be rotatable so that the polarization plane of the linearly polarized light rotates relative to the measurement object while maintaining the direction of propagation of the linearly polarized light passing through the linear polarizer, a polarization diffraction grating arranged on the optical path of the light after the linearly polarized light has passed through the measurement object and for generating diffracted light from the light, and a camera for receiving the diffracted light and generating an image representing the measurement object. The analysis device includes a control unit. The control unit executes the following processes: acquiring the images for each rotation angle of the polarization plane relative to the measurement object; calculating the light intensity of the diffracted light for each rotation angle based on multiple images acquired in the acquisition process; estimating birefringence characteristics at at least one location of the measurement object based on the progression of the light intensity with respect to the rotation angle; and outputting the characteristics.

[0015] Another example of the present disclosure provides a method for analyzing a measurement object measured by a measurement device. The measurement device includes a light source for irradiating the measurement object with light, a linear polarizer arranged on an optical path from the light source to the measurement object, a rotation drive mechanism for configuring the linear polarizer or the measurement object to be rotatable so that the polarization plane of the linearly polarized light rotates relative to the measurement object while maintaining the direction of propagation of the linearly polarized light that has passed through the linear polarizer, a polarization diffraction grating arranged on the optical path of the light after the linearly polarized light has passed through the measurement object and for generating diffracted light from the light, and a camera for receiving the diffracted light and generating an image representing the measurement object. The analysis method includes the steps of acquiring the images for each rotation angle of the polarization plane relative to the measurement object, calculating the light intensity of the diffracted light for each rotation angle based on the multiple images acquired in the acquiring step, estimating characteristics related to birefringence at at least one location of the measurement object based on the change in the light intensity with respect to the rotation angle, and outputting the characteristics.

[0016] Another example of the present disclosure provides a measurement device including: a light source for irradiating a measurement object with light; a linear polarizer arranged on an optical path from the light source to the measurement object; a rotation drive mechanism for configuring the linear polarizer or the measurement object to be rotatable so that the polarization plane of the linearly polarized light rotates relative to the measurement object while maintaining the traveling direction of the linearly polarized light that has passed through the linear polarizer; a polarization diffraction grating arranged on the optical path of the light after the linearly polarized light has passed through the measurement object and for generating diffracted light from the light; and a camera for receiving the diffracted light and generating an image representing the measurement object.

[0017] The above and other objects, features, aspects and advantages of the present invention will become apparent from the following detailed description of the invention taken in conjunction with the accompanying drawings. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a diagram illustrating an example of a device configuration of an analysis system. [Figure 2] FIG. 10 is a diagram illustrating an outline of a process for estimating birefringence characteristics. [Figure 3] FIG. 1 is a diagram illustrating an example of a device configuration of a measurement device according to a related art. [Figure 4] 1A and 1B show images produced by a measurement device according to the related art; [Figure 5] 10 is a diagram schematically illustrating the polarization state of transmitted light when linearly polarized light passes through a measurement object. FIG. [Figure 6] FIG. 2 is a diagram showing a polarization diffraction grating from the Z-axis direction. [Figure 7] FIG. 10 is a diagram showing the relationship between the polarization state of transmitted light and the diffraction efficiency of a polarization diffraction grating. [Figure 8] FIG. 2 is a schematic diagram illustrating an example of a hardware configuration of an analysis device. [Figure 9] FIG. 2 illustrates an example of a functional configuration of an analysis apparatus. [Figure 10] FIG. 2 is a diagram illustrating a process of processing by a pre-processing unit. [Figure 11] 10A and 10B are diagrams illustrating a process of a light intensity acquisition unit. [Figure 12] FIG. 2 is a diagram illustrating a schematic function of an orientation direction estimation unit. [Figure 13] FIG. 2 is a diagram illustrating the function of an amplitude estimation unit. [Figure 14] FIG. 10 is a diagram illustrating an example of an estimation result. [Figure 15] FIG. 10 is a diagram showing a specific example 1 of a display mode of an estimation result. [Figure 16] FIG. 10 is a diagram showing a specific example 2 of a display mode of an estimation result. [Figure 17] 10 is a flowchart showing a part of a process executed by the analysis device. [Figure 18] 1A and 1B are diagrams showing a measurement object used in an evaluation experiment and an image obtained by photographing the measurement object. [Figure 19]It is a diagram showing experimental results obtained from an image regarding the object to be measured. [Figure 20] It is a diagram showing experimental results obtained from an image regarding the object to be measured. [Figure 21] It is a diagram showing experimental results obtained from an image regarding the object to be measured. [Figure 22] It is a diagram showing the object to be measured used in the evaluation experiment and the image obtained by photographing the object to be measured. [Figure 23] It is a diagram showing the birefringence characteristics estimated from the image for an object group. [Figure 24] It is a diagram showing the relationship between the relative rotation angle of the object to be measured with respect to the polarizer and the analyzer, and the intensity of the light transmitted through the polarizer, the object to be measured, and the analyzer.

Embodiments for Carrying Out the Invention

[0019] Hereinafter, each embodiment according to the present invention will be described while referring to the drawings. In the following description, the same parts and components are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed descriptions thereof will not be repeated. In addition, each embodiment and each modification described below may be selectively combined as appropriate.

[0020] <A. Analysis System 10> First, referring to FIG. 1, the analysis system 10 according to the embodiment will be described. FIG. 1 is a diagram showing an example of the device configuration of the analysis system 10.

[0021] As shown in FIG. 1, the analysis system 10 includes a measuring device 50 and an analyzing device 100. The measuring device 50 and the analyzing device 100 are configured to be communicable with each other. The measuring device 50 and the analyzing device 100 may be electrically connected by wire or wirelessly connected.

[0022] The measuring device 50 has a function of outputting the birefringence-related characteristics (hereinafter also referred to as "birefringence characteristics") of the measurement object SL as an image. The measurement object SL is, for example, a polymer material having birefringence characteristics. Examples of the measurement object SL include stretched films, resin products, substrates, chemical fibers (for example, fishing line and fabric), and food products (for example, sweets).

[0023] The measurement device 50 includes a light source 60 , a linear polarizer 62 , a rotary drive mechanism 64 , a stage 66 , a polarization diffraction grating 68 , and a camera 70 .

[0024] The light source 60 is configured to irradiate the measurement object SL with light L1 of a specific wavelength. The light source 60 may be an LED (Light Emitting Diode), a lamp, a laser light source, or any other light source capable of irradiating light.

[0025] The linear polarizer 62 is disposed on the optical path from the light source 60 to the measurement object SL. The linear polarizer 62 is configured to transmit linearly polarized light L2 from the light L1 emitted from the light source 60. The linearly polarized light L2 is light that vibrates on a predetermined polarization plane. The polarization plane is a plane formed by the vibration direction of the linearly polarized light L2 and the traveling direction of the linearly polarized light L2. Note that the vibration direction and the traveling direction are perpendicular to each other.

[0026] For ease of explanation, hereinafter, the direction perpendicular to the exit surface of the linear polarizer 62 for the linearly polarized light L2 will be referred to as the Z-axis direction. The Z-axis direction is parallel to the traveling direction of the linearly polarized light L2. A direction on a plane perpendicular to the Z-axis direction will be referred to as the X-axis direction. The X-axis direction corresponds to the left-right direction on the paper in FIG. 1. A direction perpendicular to the X-axis direction and the Z-axis direction will be referred to as the Y-axis direction. The Y-axis direction corresponds to the front-to-back direction on the paper in FIG. 1.

[0027] The linear polarizer 62 extends on the XY plane. When viewed from the Z-axis direction, the shape of the linear polarizer 62 may be circular, rectangular, or another shape.

[0028] The rotary drive mechanism 64 is a member for rotating the linear polarizer 62 around the Z-axis direction as the rotation axis. That is, the rotary drive mechanism 64 is configured to rotate the polarization plane of the linearly polarized light L2 relative to the measurement object SL while maintaining the traveling direction of the linearly polarized light L2 that has passed through the linear polarizer 62.

[0029] The rotation drive mechanism 64 is composed of, for example, a motor and a motor driver. The motor is attached so that the linear polarizer 62 can rotate around the Z-axis direction as the rotation axis. The motor is driven by a motor driver. The motor driver receives a control signal from the analysis device 100 and outputs an alternating current having a frequency corresponding to the control signal to the motor. This causes the linear polarizer 62 to rotate around the Z-axis direction as the rotation axis.

[0030] 1 shows an example in which the rotary drive mechanism 64 rotates the linear polarizer 62, but as long as the polarization plane of the linearly polarized light L2 rotates relative to the measurement target SL, the object driven by the rotary drive mechanism 64 is not limited to the linear polarizer 62. As an example, the rotary drive mechanism 64 may rotate the stage 66 instead of the linear polarizer 62.

[0031] Furthermore, the rotation drive mechanism 64 does not need to be a mechanism that automatically rotates the linear polarizer 62. As an example, the rotation drive mechanism 64 may be a mechanism that rotates the linear polarizer 62 in response to a user operation.

[0032] Hereinafter, the angle that the polarization plane of the linearly polarized light L2 makes with the Y-axis direction will be referred to as the rotation angle θ. Furthermore, the rotation angle θ that changes clockwise when viewed from the positive side of the Z-axis direction will be referred to as the positive side, and the rotation angle θ that changes counterclockwise when viewed from the positive side of the Z-axis direction will be referred to as the negative side. FIG. 1 shows an example in which the rotation angle θ of the linear polarizer 62 is "+α". Note that, because the linearly polarized light L2 is linked to the linear polarizer 62, the rotation angle θ of the polarization plane of the linearly polarized light L2 is synonymous with the rotation angle of the linear polarizer 62.

[0033] The stage 66 is a member for fixing the measurement object SL. The stage 66 is configured to be able to transmit linearly polarized light L2. The linearly polarized light L2 that has passed through the stage 66 is incident on the measurement object SL. The linearly polarized light L2 then passes through the measurement object SL as transmitted light L3. The polarization state of the transmitted light L3 changes depending on the birefringence characteristics of the measurement object SL. How the polarization state of the transmitted light L3 changes will be described later.

[0034] The polarization diffraction grating 68 is disposed on the optical path of the transmitted light L3 after the linearly polarized light L2 passes through the measurement object SL. The transmitted light L3 that passes through the polarization diffraction grating 68 is separated into a plurality of diffracted light beams L4 and a straight light beam L5. The straight light beam L5 corresponds to a zeroth-order light beam. The diffracted light beam L4 includes, for example, a diffracted light beam L4A that is a +1st-order light beam and a diffracted light beam L4B that is a -1st-order light beam.

[0035] The diffraction efficiency of the diffracted light L4 changes depending on the polarization state of the transmitted light L3 incident on the polarization diffraction grating 68. Therefore, the polarization state of the transmitted light L3 can be estimated from the light intensity of the diffracted light L4.

[0036] The camera 70 is disposed on the optical path of the diffracted light L4, and generates an image representing the measurement object SL by receiving the diffracted light L4. The camera 70 is equipped with, for example, a camera lens, and is configured to be able to capture an image of the brightness and darkness of light intensity occurring at a distant position.

[0037] Preferably, the camera 70 is placed in a position where it does not receive the straight light L5. As an example, the camera 70 is placed on the optical path of the diffracted light L4A, which is +1st order light. Alternatively, the camera 70 may be placed on the optical path of the diffracted light L4B, which is -1st order light. This allows the camera 70 to generate an image according to the light intensity of the diffracted light L4. The image generated by the camera 70 is output to the analysis device 100.

[0038] The analysis device 100 is a computer. The analysis device 100 is a notebook or desktop PC (Personal Computer), a tablet terminal, or other terminal that can communicate with the measurement device 50. The analysis device 100 may be integrally configured with the measurement device 50 or may be configured separately from the measurement device 50.

[0039] <B. Overview of Analysis Processing> The analysis device 100 has a function for estimating the birefringence characteristics of the measurement object SL. Hereinafter, with reference to FIG. 1 described above and FIG. 2, the outline of the birefringence characteristic estimation process will be described. FIG. 2 is a diagram schematically showing the birefringence characteristic estimation process.

[0040] First, while the rotation drive mechanism 64 rotates the linear polarizer 62, the analysis device 100 outputs a plurality of shooting instructions to the camera 70 and acquires images separately from the rotation angle θ of the linear polarizer 62. The pixel value of the image correlates with the light intensity of the diffracted light L4. In the example of FIG. 2, images IM1 to IM9 taken at different timings of the rotation angle θ are shown.

[0041] More specifically, the image IM1 is an image obtained at the timing when the rotation angle θ is -90°. The image IM2 is an image obtained at the timing when the rotation angle θ is -67.5°. The image IM3 is an image obtained at the timing when the rotation angle θ is -45°. The image IM4 is an image obtained at the timing when the rotation angle θ is -22.5°. The image IM5 is an image obtained at the timing when the rotation angle θ is 0°. The image IM6 is an image obtained at the timing when the rotation angle θ is +22.5°. The image IM7 is an image obtained at the timing when the rotation angle θ is +45°. The image IM8 is an image obtained at the timing when the rotation angle θ is +67.5°. The image IM9 is an image obtained at the timing when the rotation angle θ is +90°.

[0042] The analysis device 100 calculates the light intensities I1 to I9 of the diffracted light L4 described above for different rotation angles θ based on a plurality of images IM1 to IM9. Here, the diffraction efficiency of the diffracted light L4 in the polarization diffraction grating 68 changes according to the relationship between the birefringence characteristics of the measurement object SL and the rotation angle θ of the linear polarizer 62. Focusing on this point, the analysis device 100 estimates the birefringence characteristics of the measurement object SL from the transition SH of the light intensities I1 to I9 of the diffracted light L4.

[0043] <C. Advantages> Next, while referring to FIG. 2 described above, the advantages of the above estimation process will be described by comparing them with related technologies by referring to FIGS. 3 and 4.

[0044] First, referring to FIG. 3, a measurement device 50X according to the related technology will be described. FIG. 3 is a diagram showing an example of the device configuration of the measurement device 50X.

[0045] The measurement device 50X according to the related technology is a measurement device that employs the cross-nicol method. More specifically, it includes a light source 60, a linear polarizer 62, a stage 66, an analyzer 68X, and a camera 70. The measurement device 50X is different from the measurement device 50 shown in FIG. 1 in that it has an analyzer 68X instead of the polarization diffraction grating 68.

[0046] The analyzer 68X is disposed on the optical path of the transmitted light L3 after passing through the measurement object SL. The analyzer 68X is a linear polarizer. That is, the analyzer 68X is configured to transmit linearly polarized light L4X from within the transmitted light L3.

[0047] The analyzer 68X is positioned so that its transmission axis is perpendicular to the transmission axis of the linear polarizer 62. Therefore, when the measurement object SL is not located between the linear polarizer 62 and the analyzer 68X, the light L1 emitted from the light source 60 is blocked by the linear polarizer 62 and the analyzer 68X. On the other hand, when the measurement object SL is located between the linear polarizer 62 and the analyzer 68X, birefringence occurs inside the measurement object SL, and the transmitted light L3 becomes elliptically polarized light having a component perpendicular to the direction of the linearly polarized light L2. This perpendicular component passes through the analyzer 68X. In other words, the component perpendicular to the incident polarized light that passes through the analyzer 68X depends on the birefringence characteristics of the measurement object SL.

[0048] The linear polarizer 62 and the analyzer 68X are configured to rotate in unison around the Z-axis direction as the center of rotation. Alternatively, the stage 66 may be configured to rotate around the Z-axis direction as the center of rotation. However, when the stage 66 is rotated, the image of the object captured by the camera 70 also rotates, which makes the subsequent analysis procedure more complicated than when the linear polarizer 62 and the analyzer 68X are rotated in unison.

[0049] The camera 70 is disposed on the optical path of the linearly polarized light L4X, and receives the linearly polarized light L4X to generate an image according to the birefringence characteristics of the measurement object SL.

[0050] 4 is a diagram showing images IMX1 to IMX9 generated by the measurement device 50X. The images IMX1 to IMX9 are obtained by rotating the linear polarizer 62 and the analyzer 68X in conjunction with each other.

[0051] More specifically, image IMX1 is an image obtained when the rotation angle θ of the linear polarizer 62 relative to the stage 66 is −90°. Image IMX2 is an image obtained when the rotation angle θ is −67.5°. Image IMX3 is an image obtained when the rotation angle θ is −45°. Image IMX4 is an image obtained when the rotation angle θ is −22.5°. Image IMX5 is an image obtained when the rotation angle θ is 0°. Image IMX6 is an image obtained when the rotation angle θ is +22.5°. Image IMX7 is an image obtained when the rotation angle θ is +45°. Image IMX8 is an image obtained when the rotation angle θ is +67.5°. Image IMX9 is an image obtained when the rotation angle θ is +90°.

[0052] As shown in FIG. 4, a transition SHX of light intensity can be obtained from images IMX1 to IMX9. Here, in the measurement device 50X according to the related art, the light intensity obtained from two images with a rotation angle θ that differs by 90° is the same. As an example, the light intensity IX2 shown in image IMX2 is the same as the light intensity IX6 shown in image IMX6. As another example, the light intensity IX4 shown in image IMX4 is the same as the light intensity IX8 shown in image IMX8.

[0053] On the other hand, in the measurement device 50 according to the embodiment, as shown in Fig. 2, the light intensities obtained from two images with a rotation angle θ that differs by 90° are different from each other. As an example, the light intensity I2 shown in image IM2 is different from the light intensity I6 shown in image IM6. As another example, the light intensity I4 shown in image IM4 is different from the light intensity I8 shown in image IM8.

[0054] Thus, in the measurement apparatus 50 according to the embodiment, the resolution of the birefringence characteristics of the measurement object appears to be higher than that of the measurement apparatus 50X according to the related art, despite the same 180° rotation operation. As a result, the analysis apparatus 100 can estimate the birefringence characteristics of the measurement object in more detail.

[0055] <D. Principle Explanation> Next, referring to FIGS. 5 to 7, the principle of obtaining different images when the rotation angle θ is different by 90° will be described. FIG. 5 is a diagram schematically showing the polarization state of transmitted light L3 when linearly polarized light L2 passes through measurement objects SL1 and SL2.

[0056] In FIG. 5(A), a measurement object SL1 as a stretched film extending in the Y-axis direction is shown. The measurement object SL1 has a principal refractive index Nx in the X-axis direction and a principal refractive index Ny in the Y-axis direction. In the example of FIG. 5(A), the principal refractive index Ny is larger than the principal refractive index Nx. Therefore, when linearly polarized light L2 passes through the measurement object SL1, a phase difference (retardation) due to birefringence occurs between the light component of linearly polarized light L2 in the X-axis direction and the light component of linearly polarized light L2 in the Y-axis direction, and the transmitted light L3 becomes elliptically polarized light rotating clockwise.

[0057] On the other hand, in FIG. 5(B), it is shown as a measurement object SL2 as a stretched film extending in the X-axis direction. The measurement object SL2 has a principal refractive index Nx in the X-axis direction and a principal refractive index Ny in the Y-axis direction. In the example of FIG. 5(B), the principal refractive index Ny is smaller than the principal refractive index Nx. Therefore, when linearly polarized light L2 passes through the measurement object SL2, a phase difference (retardation) due to birefringence occurs between the light component of linearly polarized light L2 in the X-axis direction and the light component of linearly polarized light L2 in the Y-axis direction, and the transmitted light L3 becomes elliptically polarized light rotating counterclockwise.

[0058] This means that if the rotation direction of the transmitted light L3 can be specified, the stretching direction (optical axis) of the measurement objects SL1 and SL2 can be estimated. Therefore, in the measurement apparatus 50 according to the embodiment, a polarization diffraction grating 68 whose diffraction efficiency changes according to the rotation direction and ellipticity of the transmitted light L3 is provided.

[0059] Referring to FIG. 6, an example of the configuration of the polarization diffraction grating 68 will be described. FIG. 6 is a diagram showing the polarization diffraction grating 68 from the Z-axis direction.

[0060] Groups of grating units 68A to 68D are formed periodically along the X-axis direction in polarization diffraction grating 68. In the example of Fig. 6, the groups of grating units 68A to 68D are formed at a period of 7.5 [µm].

[0061] Each of the lattice units 68A to 68D is composed of a plurality of lattices periodically formed along the Y-axis direction. More specifically, the liquid crystal molecules of each lattice that constitutes lattice unit 68A are oriented at ±0° with respect to the Y-axis direction. The liquid crystal molecules of each lattice that constitutes lattice unit 68B are oriented at +45° with respect to the Y-axis direction. The liquid crystal molecules of each lattice that constitutes lattice unit 68C are oriented at +90° with respect to the Y-axis direction. The liquid crystal molecules of each lattice that constitutes lattice unit 68D are oriented at -45° with respect to the Y-axis direction. The maximum diffraction efficiency of polarization diffraction grating 68 is, for example, approximately 80% at a wavelength of 1550 nm.

[0062] The characteristics of the polarization grating 68 will be described with reference to Fig. 7. Fig. 7 is a diagram showing the relationship between the polarization state of transmitted light L3 and the diffraction efficiency of the polarization grating 68.

[0063] The horizontal axis of the graph shown in Figure 7 represents the phase difference between the light component of transmitted light L3 in the X-axis direction and the light component of transmitted light L3 in the Y-axis direction. This phase difference represents the polarization state of transmitted light L3. In Figure 7, a schematic diagram of this polarization state is shown along the horizontal axis.

[0064] 7 represents the diffraction efficiency of polarization grating 68. Diffraction efficiency represents the ratio of the light intensity of diffracted light in a predetermined direction to the light intensity of transmitted light L3 incident on polarization grating 68.

[0065] 7, the light intensity of the diffracted light L4A, which is +1st-order light, decreases as the phase difference changes from -180° to 0°, and the light intensity of the diffracted light L4A, which is +1st-order light, increases as the phase difference changes from 0° to 180°.

[0066] Here, when the phase difference is 45°, the transmitted light L3 becomes counterclockwise elliptically polarized light, and when the phase difference is 135°, the transmitted light L3 becomes clockwise elliptically polarized light. At this time, according to the rotation direction of the transmitted light L3, the light intensity of the diffracted light L4A, which is the +1st order light, changes. Therefore, the camera 70 can capture the difference in the rotation direction of the transmitted light L3 as an image by being arranged on the optical path of the diffracted light L4A.

[0067] Note that the diffracted light L4B, which is the -1st order light, exhibits properties opposite to those of the diffracted light L4A, which is the +1st order light. That is, as the phase difference goes from -180° to 0°, the light intensity of the diffracted light L4B, which is the -1st order light, increases. And as the phase difference goes from 0° to 180°, the light intensity of the diffracted light L4B, which is the -1st order light, decreases. Therefore, even when the camera 70 is arranged on the optical path of the diffracted light L4B, it can capture the difference in the rotation direction of the transmitted light L3 as an image.

[0068] <E. Hardware Configuration of the Analyzer 100> Next, referring to FIG. 8, the hardware configuration of the analyzer 100 shown in FIG. 1 will be described. FIG. 8 is a schematic diagram showing an example of the hardware configuration of the analyzer 100.

[0069] The analyzer 100 includes a control device 101, a ROM (Read Only Memory) 102, a RAM (Random Access Memory) 103, a communication interface 104, a display interface 105, an input interface 107, and an auxiliary storage device 120. These components are connected to a bus 110.

[0070] The control device 101 is configured, for example, by at least one integrated circuit. The integrated circuit may be configured, for example, by at least one central processing unit (CPU), at least one graphics processing unit (GPU), at least one application specific integrated circuit (ASIC), at least one field programmable gate array (FPGA), or a combination thereof.

[0071] The control device 101 controls the operation of the analysis device 100 by executing various programs such as the analysis program 122 and the operating system. Upon receiving an execution command for one of the various programs, the control device 101 reads the program from the auxiliary storage device 120 or the ROM 102 into the RAM 103. The RAM 103 functions as a working memory and temporarily stores various data required for the execution of the various programs.

[0072] A LAN (Local Area Network), an antenna, and the like are connected to the communication interface 104. The analytical device 100 exchanges data with external devices via the communication interface 104. Such external devices include, for example, the measurement device 50 and other communication devices.

[0073] A display 106 is connected to the display interface 105. The display interface 105 sends an image signal for displaying an image to the display 106 in accordance with a command from the control device 101 or the like. The display 106 is, for example, a liquid crystal display, an organic EL (Electro Luminescence) display, or other display device. The display 106 may be configured integrally with the analysis device 100 or may be configured separately from the analysis device 100.

[0074] An input device 108 is connected to the input interface 107. The input device 108 is, for example, a mouse, a keyboard, a touch panel, or any other device capable of receiving user operations. Note that the input device 108 may be integrally configured with the analyzer 100 or may be configured separately from the analyzer 100.

[0075] The auxiliary storage device 120 is, for example, a hard disk, a flash memory, an SSD (Solid State Drive), and other storage media. The auxiliary storage device 120 stores an analysis program 122 and an estimation result 124 described later. The storage locations of the analysis program 122 and the estimation result 124 described later are not limited to the auxiliary storage device 120 and may be stored in the storage area of the control device 101 (for example, cache memory), ROM 102, RAM 103, external devices, etc.

[0076] Note that the analysis program 122 may be provided not as a single program but incorporated into a part of any program. In this case, the analysis process by the analysis program 122 is realized in cooperation with any program. Even a program that does not include such a part of the module does not deviate from the gist of the analysis program 122 according to the present embodiment. Furthermore, some or all of the functions provided by the analysis program 122 may be realized by dedicated hardware. Furthermore, the analyzer 100 may be configured in a form such as a so-called cloud service in which at least one server executes a part of the processing of the analysis program 122.

[0077] <F. Functional Configuration of Analyzer 100> Next, referring to FIGS. 9 to 14, the functional configuration of the analyzer 100 will be described. FIG. 9 is a diagram showing an example of the functional configuration of the analyzer 100.

[0078] 9, by executing the above-described analysis program 122, the analysis device 100 functions as an image acquisition unit 152, a preprocessing unit 154, a light intensity acquisition unit 156, an estimation unit 158, and an output unit 162. These functional configurations will be described in order below.

[0079] 9 does not need to be implemented in the analysis device 100. As an example, some of the functional configuration shown in FIG. 9 may be implemented in the measurement device 50, or may be implemented in an external device such as a server.

[0080] (F1. Image acquisition unit 152) First, the function of the image acquisition unit 152 shown in FIG. 9 will be described.

[0081] The image acquisition unit 152 is a functional module for acquiring an image IM showing the measurement target SL from the measurement device 50.

[0082] More specifically, first, the image acquiring unit 152 outputs a rotation drive command to the above-mentioned rotation drive mechanism 64. As a result, the linear polarizer 62 rotates relative to the measurement target SL. At this time, the image acquiring unit 152 rotates the linear polarizer 62 by at least 180° or more.

[0083] Next, while the rotary drive mechanism 64 is rotating the linear polarizer 62, the image acquisition unit 152 outputs a plurality of image capture instructions to the camera 30. As a result, the image acquisition unit 152 acquires a plurality of images IM of the measurement target SL from the camera 30. Then, the image acquisition unit 152 associates the rotation angle θ of the linear polarizer 62 with each of the images IM, and stores the acquired images IM. The images IM are stored in, for example, the auxiliary storage device 120.

[0084] (F2. Preprocessing unit 154) Next, the function of pre-processing unit 154 shown in Fig. 9 will be described with reference to Fig. 10. Fig. 10 is a diagram schematically showing the process of processing by pre-processing unit 154.

[0085] The preprocessing unit 154 performs preprocessing on each of the multiple images IM acquired by the image acquisition unit 152 to reduce the amount of information in the image IM.

[0086] A specific example of preprocessing will be described using image IM1 shown in FIG. 10 as an example. Image IM1 is one of multiple images IM acquired by image acquisition unit 152. First, preprocessing unit 154 divides image IM1 into multiple image regions. The number of divisions into the image may be predetermined or may be arbitrarily set by the user. Then, preprocessing unit 154 averages pixel values ​​for each divided image region to generate preprocessed image IM1. The preprocessing is performed for each image IM acquired by image acquisition unit 152.

[0087] Note that the preprocessing performed by the preprocessing unit 154 is not limited to the above example, and any image processing that can reduce the resolution of the image IM may be performed as the preprocessing. Also, the preprocessing does not necessarily have to be performed.

[0088] (F3. Light intensity acquisition section 156) Next, the function of the light intensity acquisition section 156 shown in Fig. 9 will be described with reference to Fig. 11. Fig. 11 is a diagram schematically showing the process of processing by the light intensity acquisition section 156.

[0089] The light intensity acquisition unit 156 acquires the transition of light intensity based on the images IM1 to IM9 after preprocessing by the preprocessing unit 154. The transition of light intensity is acquired for each of the image regions AR1 to ARM divided during preprocessing by the preprocessing unit 154. In other words, the light intensity acquisition unit 156 acquires the transition SH from the light intensity indicated by the same image region of the images IM1 to IM9.

[0090] Focusing on the same image region AR1 of images IM1 to IM9, a more specific process will be described. First, the light intensity acquisition unit 156 acquires the light intensity in the image region AR1 for each rotation angle θ with reference to images IM1 to IM9. The light intensity may be, for example, a pixel value at a representative point in the image region AR1, an average value of the pixel values ​​in the image region AR1, or another value calculated from the pixel values ​​in the image region AR1.

[0091] Next, the light intensity acquisition unit 156 arranges the calculated light intensities in order of the rotation angle θ to acquire a light intensity transition SH1. Since the light intensities are discrete, the light intensity acquisition unit 156 preferably interpolates between the light intensities using an arbitrary interpolation algorithm. The interpolation algorithm may be linear interpolation, cubic spline interpolation, Lagrange interpolation, or discrete light intensity interpolation.

[0092] As a result, the light intensity acquisition section 156 acquires the light intensity transition SH1 from the same image region AR1 of the images IM1 to IM9. The light intensity acquisition section 156 also performs this process on the other image regions AR2 to ARM. As a result, the light intensity acquisition section 156 acquires the light intensity transitions SH2 to SHM for the image regions AR2 to ARM, respectively.

[0093] Preferably, the light intensity transition SH can be obtained from five or more images, which allows the transition SH to be approximated as a sine wave, thereby enabling more accurate estimation of birefringence characteristics.

[0094] (F4. Estimation part 158) Next, the function of the estimation unit 158 ​​shown in FIG. 9 will be described with reference to FIGS.

[0095] The estimation unit 158 ​​estimates the birefringence characteristics at at least one location of the measurement object SL based on the transition SH of the light intensity with respect to the rotation angle θ.

[0096] The birefringence characteristics to be estimated may be one type or multiple types. In one aspect, estimation unit 158 ​​functions as orientation direction estimation unit 158A and estimates the molecular orientation direction of measurement object SL based on the transition SH of light intensity with respect to rotation angle θ. In another aspect, estimation unit 158 ​​functions as amplitude estimation unit 158B and estimates the amount of change in light intensity based on the transition SH of light intensity with respect to rotation angle θ.

[0097] The functions of the orientation estimation unit 158A and the amplitude estimation unit 158B will be described below in order.

[0098] (a) Orientation direction estimation unit 158A First, the function of the alignment direction estimation unit 158A will be described with reference to Fig. 12. Fig. 12 is a diagram schematically showing the function of the alignment direction estimation unit 158A.

[0099] The orientation direction estimation unit 158A estimates the molecular orientation direction of the measuring object SL based on the transition SH of light intensity calculated by the light intensity acquisition unit 156. The molecular orientation direction is estimated for each of the image regions AR1 to ARM, for example.

[0100] Here, the molecular orientation direction estimation process will be described, focusing on the light intensity transition SH1 acquired from the image region AR1. First, the orientation direction estimation unit 158A identifies a point Pmax where the light intensity is maximum within the light intensity transition SH1. Next, the orientation direction estimation unit 158A identifies a rotation angle θ0 corresponding to the point Pmax. The rotation angle θ0 becomes a reference angle for estimating the molecular orientation direction. Thereafter, the orientation direction estimation unit 158A estimates a rotation angle θ1, which is the reference angle, minus a predetermined angle Δθ from the rotation angle θ0, as the molecular orientation direction. The magnitude of the predetermined angle Δθ is, for example, 45°.

[0101] Although the above description has been given of an example in which the molecular orientation direction is estimated based on the rotation angle θ0 corresponding to the point Pmax of maximum light intensity, the method of estimating the molecular orientation direction is not limited to the above example. As an example, the orientation direction estimation unit 158A may estimate the molecular orientation direction based on the rotation angle corresponding to the point of minimum light intensity. In this case, the orientation direction estimation unit 158A adds a predetermined angle (e.g., 45°) to the rotation angle corresponding to the minimum light intensity in the transition SH1, and estimates the rotation angle indicated by the addition result as the molecular orientation direction.

[0102] As described above, the orientation direction estimation unit 158A estimates the molecular orientation direction based on at least one of the rotation angle corresponding to the maximum light intensity in the light intensity transition SH1 and the rotation angle corresponding to the minimum light intensity in the light intensity transition SH1.

[0103] (b) Amplitude estimation section 158B Next, the function of the amplitude estimation section 158B will be described with reference to Fig. 13. Fig. 13 is a diagram schematically showing the function of the amplitude estimation section 158B.

[0104] The amplitude estimation unit 158B estimates the amount of change in light intensity (hereinafter also referred to as "amplitude") based on the light intensity transition SH calculated by the light intensity acquisition unit 156. The light intensity amplitude is a physical quantity correlated with the phase difference (retardation) between the ordinary light component and the extraordinary light component when linearly polarized light L2 passes through the measurement target SL, which is a birefringent medium. More specifically, the larger the phase difference between the ordinary light component and the extraordinary light component, the larger the estimated light intensity amplitude. In other words, the smaller the phase difference between the ordinary light component and the extraordinary light component, the smaller the estimated light intensity amplitude. The light intensity amplitude is estimated for each of the image regions AR1 to AR1.

[0105] Here, focusing on the transition SH1 obtained from the image region AR1, a method for estimating the amplitude of the light intensity will be described. First, the amplitude estimation unit 158B identifies the point Pmax where the light intensity is maximum within the transition SH1 and the point Pmin where the light intensity is minimum within the transition SH1. Next, the amplitude estimation unit 158B calculates the photometric difference ΔI between the maximum light intensity Imax corresponding to the point Pmax and the minimum light intensity Imin corresponding to the point Pmin, and estimates the photometric difference ΔI as the light intensity amplitude.

[0106] Note that the method for calculating the light intensity amplitude is not limited to the above example, and any algorithm capable of identifying the amplitude of the transition SH can be adopted.

[0107] (F5.Output unit 162) Next, referring to FIG. 14, the function of the output unit 162 shown in FIG. 9 will be described.

[0108] The output unit 162 outputs the estimation result 124 by the estimation unit 158 in some form. FIG. 14 is a diagram showing an example of the estimation result 124.

[0109] The estimation result 124 associates the transition of the light intensity acquired by the light intensity acquisition unit 156, the molecular orientation direction estimated by the orientation direction estimation unit 158A, and the amplitude of the light intensity estimated by the amplitude estimation unit 158B for each of the above-described image regions AR1 to ARM.

[0110] The storage destination of the estimation result 124 is arbitrary. As an example, the estimation result 124 is stored in the auxiliary storage device 120 of the analyzer 100. Alternatively, the estimation result 124 may be stored in the measuring device 50 or may be stored in an external device such as a server.

[0111] <G.Display mode> The output unit 162 displays the estimation result 124 in any display mode that is easy for the user to visually recognize. Hereinafter, specific examples of the display mode of the estimation result 124 will be described with reference to FIGS. 15 and FIG. 16.

[0112] The display destination of the inference result 124 is arbitrary. As one example, the display destination of the inference result 124 is the display 106 of the analysis device 100. As another example, the display destination of the inference result 124 may be the display (not shown) of the measurement device 50. As yet another example, the display destination of the inference result 124 may be the display of an external device such as a user terminal.

[0113] The following description will be given on the assumption that the display destination of the estimation result 124 is the display 106 of the analysis device 100.

[0114] (G1. Example 1) An example of a display mode of the estimation result 124 will be described with reference to Fig. 15. Fig. 15 is a diagram showing a specific example 1 of a display mode of the estimation result 124.

[0115] 15, an image IM obtained by photographing a measurement object SL1 is displayed on the display 106. The measurement object SL1 is a stretched film stretched in a specific direction. The analysis device 100 represents the birefringence characteristics estimated for the measurement object SL1 on the image IM using an object OB1.

[0116] As an example, the object OB1 is displayed in a manner that allows the molecular orientation direction estimated by the above-described orientation direction estimation unit 158A to be visually recognized. In the example of Fig. 15, the object OB1 is displayed with a bidirectional arrow. This allows the user to easily understand the molecular orientation direction estimated for the measurement target SL1.

[0117] Preferably, the object OB1 is displayed superimposed on the position of the estimated position P1 of the molecular orientation direction. Note that the object OB1 does not necessarily have to be displayed superimposed on the image IM, and may be displayed adjacent to the image IM.

[0118] As another example, object OB1 is displayed with a length according to the amplitude of the light intensity estimated by the amplitude estimation unit 158B described above. More specifically, the analysis device 100 lengthens the arrow indicated by object OB1 as the estimated amplitude of the light intensity increases. On the other hand, the analysis device 100 shortens the length of the arrow indicated by object OB1 as the estimated amplitude of the light intensity decreases. This allows the user to easily grasp the amplitude of the light intensity estimated for the measurement target SL1.

[0119] The image IM on which the object OB1 is superimposed can be arbitrarily selected from among the images acquired by the image acquisition unit 152. The image may be selected by the user or may be selected according to a predetermined rule.

[0120] (G2. Example 2) Next, another example of the display mode of the estimation result 124 will be described with reference to Fig. 16. Fig. 16 is a diagram showing a specific example 2 of the display mode of the estimation result 124.

[0121] In the above-described FIG. 15, an example was described in which the measurement object SL1 is a stretched film. For such a measurement object SL1 stretched in a single direction, the birefringence characteristics can be adequately represented with a small number of objects OB1. However, for a measurement object SL2 having a more complex molecular orientation distribution, the birefringence characteristics vary at each location on the measurement object SL2. Therefore, in this example, the analysis device 100 displays an object OB2 showing the birefringence characteristics for each of multiple estimation locations P2. Note that each estimation location P2 corresponds to one of the image regions shown in the estimation result 124.

[0122] In this example, the analysis device 100 displays multiple objects OB2 superimposed on an image IM obtained by capturing an image of a measurement object SL2. The measurement object SL2 is, for example, a resin product. When molding a resin product, molten resin is poured into a mold from multiple different locations. Therefore, the birefringence characteristics of the resin product differ from location to location.

[0123] Therefore, the object OB2 is displayed at a position corresponding to each image region shown in the estimation result 124. At this time, each of the objects OB2 is displayed in a manner that allows the molecular orientation direction estimated by the above-described orientation direction estimation unit 158A to be visually recognized. The object OB2 may be represented by a bidirectional arrow like the above-described object OB1 (see FIG. 15), or may be represented by a single-directional arrow. This allows the user to easily grasp the distribution of molecular orientation directions for the measurement target SL2.

[0124] In resin products, weld lines occur during molding. A weld line is a portion where molten resins mix together when injected into a mold from various locations. In the example of FIG. 16, a weld line WL appears in the image IM. As an example, each object OB2 is indicated by a single-directional arrow that makes the weld line WL visible. Furthermore, the direction of the arrow indicated by each object OB2 may be switched to the opposite direction for each group on either side of the weld line WL. The direction of the arrow can be switched, for example, in response to a user operation.

[0125] Furthermore, each object OB2 is displayed with a length according to the amplitude of the light intensity estimated by the amplitude estimation unit 158B described above. More specifically, the analysis device 100 lengthens the arrow indicated by the object OB2 as the estimated amplitude of the light intensity increases. On the other hand, the analysis device 100 shortens the length of the arrow indicated by the object OB2 as the estimated amplitude of the light intensity decreases. This allows the user to easily grasp the distribution of the light intensity amplitude for the measurement target SL2.

[0126] The image IM on which the object OB2 is superimposed can be arbitrarily selected from among the multiple images IM acquired by the image acquisition unit 152. The image may be selected by the user or may be selected according to a predetermined rule.

[0127] (G3. Example 3) Next, still another example of the display mode of the estimation result 124 will be described.

[0128] 16, the object OB2 indicating the birefringence characteristics of the measurement target SL2 is displayed at each of the estimation locations. However, the object OB2 does not need to be displayed at all of the estimation locations.

[0129] As an example, object OB2 may be displayed only at a location designated by the user. In this case, first, image IM showing object OB2 is displayed on display 106. Next, the user designates an arbitrary location in image IM using input device 108 (see FIG. 8 ) or the like. Next, analysis device 100 displays object OB2 superimposed on the location designated by the user. This allows the user to analyze the birefringence characteristics of the location of interest.

[0130] <H.フローチャート> Next, the control structure of analysis device 100 will be described with reference to Fig. 17. Fig. 17 is a flowchart showing part of the processing executed by analysis device 100.

[0131] 17 is realized by the control device 101 of the analysis device 100 executing the above-described analysis program 122. In another aspect, some or all of the processing may be performed by circuit elements or other hardware.

[0132] In step S112, the control device 101 functions as the image acquisition unit 152 (see FIG. 9 ) described above, outputs a rotation drive command to the rotation drive mechanism 64 described above, and outputs a plurality of image capture instructions to the camera 30 described above while the linear polarizer 62 is rotating. As a result, the image acquisition unit 152 acquires a plurality of images IM of the measurement object SL from the camera 30 for each angle of the linear polarizer 62.

[0133] In step S114, the control device 101 functions as the above-described preprocessing unit 154 (see FIG. 9), and performs preprocessing for thinning out the information amount of the image IM on each of the plurality of images IM acquired in step S112. Since the functions of the preprocessing unit 154 are as described above, the description thereof will not be repeated.

[0134] In step S116, the control device 101 functions as the above-described light intensity acquisition unit 156 (see FIG. 9), and acquires the transition SH of the light intensity based on the image IM after the preprocessing in step S114. Since the functions of the light intensity acquisition unit 156 are as described above, the description thereof will not be repeated.

[0135] In step S118, the control device 101 functions as the above-described orientation direction estimation unit 158A (see FIG. 9), and estimates the molecular orientation direction of the measurement object SL based on the transition SH of the light intensity acquired in step S116. Since the functions of the orientation direction estimation unit 158A are as described above, the description thereof will not be repeated.

[0136] In step S120, the control device 101 functions as the above-described amplitude estimation unit 158B (see FIG. 9), and estimates the amplitude of the light intensity based on the transition SH of the light intensity acquired in step S116. Since the functions of the amplitude estimation unit 158B are as described above, the description thereof will not be repeated.

[0137] In step S122, the control device 101 functions as the above-described output unit 162 (see FIG. 9), and outputs the estimation results 124 in steps S118 and S120. Since the functions of the output unit 162 are as described above, the description thereof will not be repeated.

[0138] <I. Example 1> The inventor conducted an evaluation experiment to verify that the birefringence characteristics of the measurement object SL can be estimated by the above-described processing. Hereinafter, each evaluation experiment conducted by the inventor will be described in order.

[0139] (I1. Example 1) First, an evaluation experiment according to Example 1 will be described with reference to Fig. 18 to Fig. 21. Fig. 18 is a diagram showing measurement objects SLA to SLC used in this evaluation experiment and images IM11 to IM19 obtained by photographing the measurement objects SLA to SLC.

[0140] Measurement objects SLA to SLC are stretched films with known stretching directions. The stretching direction (optical axis) of measurement object SLA is 0°. The stretching direction (optical axis) of measurement object SLB is -45°. The stretching direction (optical axis) of measurement object SLC is -90°.

[0141] With the measurement objects SLA to SLC placed on the stage 66, the inventor photographed the measurement objects SLA to SLC with the measurement device 50 while changing the rotation angle θ of the linear polarizer 62. In this way, the inventor obtained images IM11 to IM19.

[0142] More specifically, image IM11 is an image obtained when the rotation angle θ is −90°. Image IM12 is an image obtained when the rotation angle θ is −67.5°. Image IM13 is an image obtained when the rotation angle θ is −45°. Image IM14 is an image obtained when the rotation angle θ is −22.5°. Image IM15 is an image obtained when the rotation angle θ is 0°. Image IM16 is an image obtained when the rotation angle θ is +22.5°. Image IM17 is an image obtained when the rotation angle θ is +45°. Image IM18 is an image obtained when the rotation angle θ is +67.5°. Image IM19 is an image obtained when the rotation angle θ is +90°.

[0143] Fig. 19 is a diagram showing experimental results obtained from images IM11 to IM19 of the measurement object SLA. Fig. 19 shows the experimental results of the transition SHA of the light intensity obtained from the image area in which the measurement object SLA is captured.

[0144] As explained above in FIG. 12, the orientation estimation unit 158A considers the value obtained by subtracting 45° from the rotation angle θ corresponding to the maximum light intensity as the molecular orientation direction. The inventors confirmed from the transition SHA that the light intensity is maximum when the rotation angle θ is near 45°, and that the molecular orientation direction estimated from the rotation angle θ is near 0°. This result coincides with the extension direction (optical axis) of the measurement object SLA. As described above, the inventors confirmed that the molecular orientation direction of the measurement object SLA can be estimated from the transition SHA of the light intensity.

[0145] Fig. 20 is a diagram showing experimental results obtained from images IM11 to IM19 for the measurement object SLB. Fig. 20 shows the experimental results of the light intensity transition SHB obtained from the image area in which the measurement object SLB is captured.

[0146] The inventors confirmed from the transition SHB that the light intensity is at its maximum when the rotation angle θ is approximately -22.5 to 0°, and that the molecular orientation direction estimated from the rotation angle θ is approximately -67.5 to -45°. This result coincides with the extension direction (optical axis) of the measurement object SLB. As described above, the inventors confirmed that the molecular orientation direction of the measurement object SLB can be estimated from the transition SHB of the light intensity.

[0147] Fig. 21 is a diagram showing experimental results obtained from images IM11 to IM19 of the measurement object SLC. Fig. 21 shows the experimental results of the transition SHC of light intensity obtained from the image area in which the measurement object SLC is captured.

[0148] The inventors confirmed from the SHC transition that the light intensity is at its maximum when the rotation angle θ is around -45°, and that the molecular orientation direction estimated from the rotation angle θ is around -90°. This result coincides with the stretching direction (optical axis) of the SLC to be measured. As described above, the inventors confirmed that the molecular orientation direction of the SLC to be measured can be estimated from the SHC transition of the light intensity.

[0149] (I2. Example 2) Next, an evaluation experiment according to Example 2 will be described with reference to Fig. 22 and Fig. 23. Fig. 22 is a diagram showing a measurement object SLD used in this evaluation experiment and images IM21 to IM33 obtained by photographing the measurement object SLD.

[0150] The measurement object SLD is a resin product whose molding process is known. More specifically, the resin product is molded by pouring molten resin into a mold. Injection points IN1 and IN2 shown in FIG. 22 correspond to the injection points of the molten resin into the mold. Therefore, a weld line WL is formed between the injection points IN1 and IN2 of the molten resin.

[0151] The inventor placed a fragment including the weld line WL on the above-mentioned stage 66, and photographed the fragment with the measuring device 50 while changing the rotation angle θ of the linear polarizer 62. In this way, the inventor obtained images IM21 to IM33.

[0152] More specifically, image IM21 is an image obtained when the rotation angle θ is −90°. Image IM22 is an image obtained when the rotation angle θ is −75°. Image IM23 is an image obtained when the rotation angle θ is −60°. Image IM24 is an image obtained when the rotation angle θ is −45°. Image IM25 is an image obtained when the rotation angle θ is −30°. Image IM26 is an image obtained when the rotation angle θ is −15°. Image IM27 is an image obtained when the rotation angle θ is 0°. Image IM28 is an image obtained when the rotation angle θ is 15°. Image IM29 is an image obtained when the rotation angle θ is 30°. Image IM30 is an image obtained when the rotation angle θ is 45°. Image IM31 is an image obtained when the rotation angle θ is 60°. Image IM32 is an image obtained when the rotation angle θ is 75°, and image IM33 is an image obtained when the rotation angle θ is 90°.

[0153] FIG. 23 is a diagram showing the birefringence characteristics estimated from the images IM21 to IM33 by the object groups OBA to OBC.

[0154] As described in FIGS. 15 and 16 above, the directions indicated by the objects in the object groups OBA to OBC correspond to the estimation results of the molecular orientation direction. The lengths indicated by the objects in the object groups OBA to OBC correspond to the estimation results of the amplitude of the light intensity.

[0155] In the vicinity of the object group OBA, it was confirmed that the molecular orientation direction is directed toward the weld line WL. This result is consistent with the flow direction of the molten resin injected from the injection point IN1. Also, in the vicinity of the object group OBA, it was confirmed that the amplitude of the light intensity increases.

[0156] Similarly, in the vicinity of the object group OBB, it was confirmed that the molecular orientation direction is directed toward the weld line WL. This result is consistent with the flow direction of the molten resin injected from the injection point IN2. Also, in the vicinity of the object group OBB, it was confirmed that the amplitude of the light intensity increases.

[0157] Furthermore, in the vicinity of the object group OBC, it was confirmed that the molecular orientation direction is along the actual weld line WL. Also, in the vicinity of the object group OBC, it was confirmed that the amplitude of the light intensity increases.

[0158] From the above, the inventor confirmed that the weld line WL of the resin product can be accurately estimated.

[0159] <J. Applications> The above analysis system 10 can be adopted for various applications. As an example, the analysis system 10 can be adopted in a polarization microscope system for observing the distribution of molecular orientation of the measurement object SL. In this case, the polarization microscope system is composed of a measurement device 50 as a polarization microscope and an analyzer 100 for birefringence characteristics.

[0160] As another example, the analysis system 10 may be employed in an inspection system for inspecting an abnormality in a measurement object SL. The inspection system is composed of a measurement device 50 as an imaging device and an analysis device 100 for birefringence characteristics. The inspection system is used, for example, to inspect a weld line in a measurement object SL such as a resin product. Note that the inspection system is not limited to inspecting resin products, but may inspect various objects having birefringence characteristics, such as stretched films, substrates, chemical fibers (e.g., fishing line and fabric), and food products (e.g., sweets).

[0161] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0162] 10 analysis system, 30 camera, 50 measurement device, 50X measurement device, 60 light source, 62 linear polarizer, 64 rotation drive mechanism, 66 stage, 68 polarization diffraction grating, 68A to 68D grating unit, 68X analyzer, 70 camera, 100 analysis device, 101 control device, 102 ROM, 103 RAM, 104 communication interface, 105 display interface, 106 display, 107 input interface, 108 input device, 110 bus, 120 auxiliary storage device, 122 analysis program, 124 estimation result, 152 image acquisition unit, 154 preprocessing unit, 156 light intensity acquisition unit, 158 estimation unit, 158A orientation direction estimation unit, 158B amplitude estimation unit, 162 output unit.

Claims

1. An analysis program for a measurement object measured by a measurement device, The measuring device is a light source for irradiating the object to be measured with light; a linear polarizer disposed on an optical path from the light source to the measurement object; a rotation drive mechanism for configuring the linear polarizer or the object to be measured to be rotatable so that the polarization plane of the linearly polarized light rotates relative to the object to be measured while maintaining the traveling direction of the linearly polarized light that has passed through the linear polarizer; a polarization diffraction grating disposed on an optical path of the linearly polarized light after the linearly polarized light has passed through the object to be measured, for generating diffracted light from the linearly polarized light; a camera for receiving the diffracted light and generating an image representing the measurement object; The analysis program is installed on a computer. A process of acquiring the images for each rotation angle of the polarization plane with respect to the measurement object; a process of calculating the light intensity of the diffracted light for each of the rotation angles based on the plurality of images acquired in the acquiring process; a process of estimating a characteristic related to birefringence at at least one point of the measurement object based on a transition of the light intensity with respect to the rotation angle; and a process for outputting the characteristics.

2. The analysis program according to claim 1 , wherein the characteristics include an orientation direction of molecules of the object to be measured.

3. The analysis program according to claim 2, wherein in the estimation process, the orientation direction is estimated based on at least one of a rotation angle corresponding to a maximum light intensity in the transition and a rotation angle corresponding to a minimum light intensity in the transition.

4. 4. The analysis program according to claim 2, wherein in the outputting process, an object indicating the orientation direction is superimposed on an image representing the measurement object.

5. 4. The analysis program according to claim 1, wherein the characteristics further include an amount of change in the light intensity.

6. 6. The analysis program according to claim 5, wherein the amount of change is indicated by a difference between a maximum light intensity in the transition and a minimum light intensity in the transition.

7. The analysis program according to claim 5 , wherein in the outputting process, an object indicating the amount of change is superimposed on an image representing the object to be measured.

8. An analytical device for a measurement object measured by a measurement device, The measuring device is a light source for irradiating the object to be measured with light; a linear polarizer disposed on an optical path from the light source to the measurement object; a rotation drive mechanism for configuring the linear polarizer or the object to be measured to be rotatable so that the polarization plane of the linearly polarized light rotates relative to the object to be measured while maintaining the traveling direction of the linearly polarized light that has passed through the linear polarizer; a polarization diffraction grating disposed on an optical path of the linearly polarized light after the linearly polarized light has passed through the object to be measured, for generating diffracted light from the linearly polarized light; a camera for receiving the diffracted light and generating an image representing the measurement object; The analyzer includes a control unit, The control unit A process of acquiring the images for each rotation angle of the polarization plane with respect to the measurement object; a process of calculating the light intensity of the diffracted light for each of the rotation angles based on the plurality of images acquired in the acquiring process; a process of estimating a characteristic related to birefringence at at least one point of the measurement object based on a transition of the light intensity with respect to the rotation angle; and a process for outputting the characteristics.

9. An analysis method for a measurement object measured by a measurement device, comprising: The measuring device is a light source for irradiating the object to be measured with light; a linear polarizer disposed on an optical path from the light source to the measurement object; a rotation drive mechanism for configuring the linear polarizer or the object to be measured to be rotatable so that the polarization plane of the linearly polarized light rotates relative to the object to be measured while maintaining the traveling direction of the linearly polarized light that has passed through the linear polarizer; a polarization diffraction grating disposed on an optical path of the linearly polarized light after the linearly polarized light has passed through the object to be measured, for generating diffracted light from the linearly polarized light; a camera for receiving the diffracted light and generating an image representing the measurement object; The analysis method includes: acquiring the images for each rotation angle of the polarization plane relative to the measurement object; calculating the light intensity of the diffracted light for each of the rotation angles based on the plurality of images acquired in the acquiring step; estimating a birefringence characteristic at at least one location of the measurement object based on a transition of the light intensity with respect to the rotation angle; and outputting the characteristic.

10. a light source for irradiating the object to be measured with light; a linear polarizer disposed on an optical path from the light source to the measurement object; a rotation drive mechanism for configuring the linear polarizer or the object to be measured to be rotatable so that the polarization plane of the linearly polarized light rotates relative to the object to be measured while maintaining the traveling direction of the linearly polarized light that has passed through the linear polarizer; a polarization diffraction grating disposed on an optical path of the linearly polarized light after the linearly polarized light has passed through the object to be measured, for generating diffracted light from the linearly polarized light; a camera for receiving the diffracted light and generating an image representative of the measurement object.

Images