Space-time structure imaging device

Abstract

A space-time structure imaging device according to an embodiment includes: a first lens for receiving scattered light from an object under observation; and a second lens arranged behind the first lens. An element having the function of limiting the scattering volume and an imaging element for receiving and capturing the scattered light in units of pixels, converting the scattered light into a signal, and outputting the signal are arranged in the vicinity of a real space focal point formed behind the second lens.

Description

Spatiotemporal structure imaging device

[0001] The present invention relates to a spatiotemporal structure imaging device.

[0002] Apparently homogeneous materials such as glasses, gels, critical liquids, and supercooled liquids have isotropic symmetry similar to liquids, and because they are statically uniform and have no spatial heterogeneity, it is not possible to reveal the true nature of their internal structure or physical properties using a normal optical microscope. In recent years, it has been discovered that "dynamic heterogeneity," which cannot be observed with a normal microscope, is important for elucidating the properties of materials, and research into this has been progressing.

[0003] The present inventors have proposed a fluctuation microscope as a device for visualizing dynamic heterogeneity within a sample (see, for example, Non-Patent Document 1). Fluctuation microscopes capture scattered light from irradiated onto a sample using a high-speed imaging device such as a CCD camera, calculate the autocorrelation function of the optical signal for each pixel, analyze its relaxation time, and visualize the result using, for example, color mapping. This makes it possible to visualize the dynamic heterogeneity of each region within a sample with both temporal and spatial resolution.

[0004] On the other hand, previous research on dynamic heterogeneity in soft matter systems includes an experiment in which a CCD camera was used as a photodetector to observe dynamic light scattering (see, for example, Non-Patent Document 2). However, in this experiment, the image was averaged over the entire surface of the CCD camera, resulting in the loss of information about the spatial position of the dynamics. In other words, while this technique has a certain temporal resolution for observing the dynamic heterogeneity of a sample, it does not have spatial resolution.

[0005] Furthermore, there is a prior art example (see, for example, Non-Patent Document 3) in which the particle behavior of a high-density colloidal dispersion system is observed using a confocal microscope, but this does not make it possible to visualize the dynamics inside the sample itself.

[0006] Yusei Ukai, Yoichi Takanishi, Jun Yamamoto, "Principles and Prototypes of Fluctuation Microscopes," Proceedings of the 2017 Japanese Liquid Crystal Society Symposium, S. Maccarone, G. Brambilla, O. Pravaz, A. Duri, M. Ciccotti, J. M. Fromental, E. Pashkovski, A. Lips, D. Sessoms, V. Trappe, L. Cippeletti, Soft Matter, 2010, 6, 5514-5522, Eric R. Weeks, J. C. Rocker, Andrew C. Levitt, DA Weitz, Science 287.5453.627

[0007] As mentioned above, the present inventors proposed a fluctuation microscope as a device for observing "dynamic inhomogeneity." Non-Patent Document 1 discloses this fluctuation microscope. However, this fluctuation microscope does not recognize the measurement conditions essential for practical measurements, as described below, and does not disclose the required measurement conditions, resulting in low spatial resolution as a microscope. For this reason, conventional fluctuation microscopes have significant room for improvement in order to observe dynamic inhomogeneity with sufficient accuracy.

[0008] In view of this situation, the inventors have investigated the scattering volume limit, which is an important parameter required for observing "dynamic heterogeneity" in a practical spatiotemporal structure imaging device, and have completed the present invention.

[0009] An object of the present invention is to provide a spatiotemporal structure imaging device with high spatial resolution using a simple optical system, and also to realize a practical spatiotemporal structure imaging device such as a fluctuation microscope.

[0010] Hereinafter, with regard to devices for observing dynamic heterogeneity, the conventional device described in, for example, Non-Patent Document 1 will be referred to as a "fluctuation microscope," and the device according to the present invention will be referred to as a "space-time structure imaging device" to distinguish between the two.

[0011] In order to solve the above problems, a space-time structure imaging device according to one embodiment of the present invention comprises a first lens that receives scattered light from an observation target, and a second lens that is disposed behind the first lens. An element having a function of limiting the scattering volume and an image sensor that receives and captures the scattered light pixel by pixel, converts it into a signal, and outputs the signal are disposed near a real space focal point formed behind the second lens.

[0012] In one embodiment, when the scattering volume limiting length is P, the integrated magnification determined by the lens arranged between the first lens and the element having the function of limiting the scattering volume is M, and the wavelength of the scattered light is λ, P / M may be less than 15λ.

[0013] In one embodiment, an element having the function of limiting the scattering volume is included in the imaging element, and the scattering volume limit length P corresponds to the pixel size of the imaging element, and when the pixel size is P1, P1 / M<15λ may be satisfied.

[0014] In one embodiment, the element having the function of limiting the scattering volume may be constituted by one or more pinholes, and when the pinhole size of the pinhole is P2, P2 / M<15λ may be satisfied.

[0015] In one embodiment, a signal analysis device may be provided that converts the signal into time-series data of brightness, calculates the autocorrelation function of scattered light for each pixel, calculates the relaxation time from the autocorrelation function, and visualizes the relaxation time.

[0016] In one embodiment, when the numerical aperture of the first lens from the observation target is NA, NA may be less than 0.6.

[0017] In some embodiments, an intermediate power changer may be provided between the first lens and the second lens.

[0018] In some embodiments, a third lens and a fourth lens may be provided behind the second lens.

[0019] In one embodiment, the signal analysis device may visualize the relaxation times by color mapping.

[0020] Any combination of the above components, and any transformation of the present invention into an apparatus, method, system, recording medium, computer program, etc., are also valid aspects of the present invention.

[0021] According to the present invention, it is possible to realize a high-performance space-time structure imaging device that satisfies the required scattering volume limitations and scattering angle limitations while using a simple optical system.

[0022] 1. A functional block diagram of a fluctuation microscope according to a comparative example. A functional block diagram of a space-time structure imaging apparatus according to a first embodiment. A schematic diagram showing the operation of the space-time structure imaging apparatus of FIG. 1. A functional block diagram of a space-time structure imaging apparatus according to a second embodiment. A functional block diagram of a space-time structure imaging apparatus according to a third embodiment. A functional block diagram of a space-time structure imaging apparatus according to a fourth embodiment. A diagram showing the results of visualizing the dynamic inhomogeneity of a sample (E44 liquid crystal) by color mapping using the space-time structure imaging apparatus of the embodiment. (a) is E44 pure liquid crystal, (b) is E44 liquid crystal gel (LCG), and (c) is E44 liquid crystal polymer. An example of an image obtained using the space-time structure imaging apparatus of the embodiment. An example of an image obtained using the space-time structure imaging apparatus of the embodiment. An example of an image obtained using the space-time structure imaging apparatus of the embodiment. An example of an image obtained using the space-time structure imaging apparatus of the embodiment. An example of an image obtained using the space-time structure imaging apparatus of the embodiment. An example of an image obtained using the space-time structure imaging apparatus of the embodiment. An example of an image obtained using the space-time structure imaging apparatus of the embodiment. An example of an image obtained using the space-time structure imaging apparatus of the embodiment. An example of an image obtained using the space-time structure imaging apparatus of the embodiment. This figure shows an example of a measurement when UV light is irradiated onto a portion of a liquid crystal containing an azobenzene compound. This figure shows an example of a measurement when a mechanical external force is applied to a material. This figure shows an example of a measurement when light is irradiated onto a nematic liquid crystal gel material containing a photopolymerizable material. This figure shows an example of a measurement of the time change in the spatial distribution of dynamic heterogeneity in phase separation dynamics. This is an image obtained by observing the change in the dynamic heterogeneity of the orientational fluctuations of a sample using a space-time imaging device in the VH configuration (depolarized scattering) at a temperature near the thermal concentration transition type isotropic-nematic phase transition. This is an image obtained by observing the change in the dynamic heterogeneity of the concentration fluctuations of a sample using a space-time imaging device in the VV configuration (polarization-preserving scattering) at a temperature near the thermal concentration transition type isotropic-nematic phase transition.

[0023] The present invention will be described below based on preferred embodiments with reference to the drawings. In the embodiments and modified examples, identical or equivalent components, steps, and members are designated by the same reference numerals, and redundant descriptions will be omitted where appropriate. The dimensions of the components in the drawings are enlarged or reduced as appropriate for ease of understanding. Some components that are not important for explaining the embodiments are omitted from the drawings. Terms including ordinal numbers such as "first" and "second" are used to describe various components, but these terms are used only to distinguish one component from another and do not limit the components.

[0024] Hereinafter, in this specification, "behind the lens" means the direction from the sample toward the imaging device in the optical system, closer to the imaging device. "Near the focal position" means a position close to the focal length in front of or behind the lens in the optical system. "Scattering volume limit length" means the length of one side of a sample cube that satisfies the scattering volume limit.

[0025] Before describing specific embodiments, we will first explain the principles of this technology as fundamental knowledge. Although soft matter systems such as glass and gels appear uniform macroscopically, the mobility of internal degrees of freedom often varies from location to location. For example, regions where molecules move quickly and regions where they move slowly exist in a spatially nonuniform distribution. This phenomenon is referred to herein as "dynamic heterogeneity." Visualizing this dynamic heterogeneity (i.e., spatial changes in dynamics that do not appear in static structures) and observing its temporal changes is expected to significantly contribute to academic research, such as research into physical properties, and also be widely applicable to industries involving the analysis of the internal structure of materials.

[0026] The observation requirements for dynamic light scattering observation (i.e., observation with time resolution) and optical microscope observation (i.e., observation with spatial resolution), as well as the competing observation requirements when these two observations are performed simultaneously, can be summarized as follows:

[0027] Existing dynamic light scattering instruments that lack spatial resolution are equipped with an optical system (collection optical system) designed to satisfy two limitations (conditions) required for measurement: a "scattering volume limitation" (hereinafter referred to as "condition A") and a "scattering angle (spread) limitation" (hereinafter referred to as "condition B"). One example of such a collection optical system is a microscopic imaging optical system constructed using 2 × n (n≧1) lenses, with a pinhole of an appropriate size installed at the focal point. In this case, the pinhole located at the focal position (wavenumber space focal plane) behind the 2 × n-1th lens serves to "limit the scattering angle spread" (condition B), while the pinhole located at the focal position (real space focal plane) behind the 2 × nth lens serves to "limit the scattering volume" (condition A).

[0028] On the other hand, since the above-mentioned microscopic optical system is the same optical system as that of a normal optical microscope, it is possible to obtain a magnified image of the sample by installing, for example, a CCD camera at the focal position (real space focal plane) behind the 2×nth lens (realization of optical microscope observation method (spatial resolution)).

[0029] However, in the spatiotemporal structure imaging device of the present invention, it is necessary to simultaneously receive scattered light from each point on the sample in a two-dimensional plane and observe fluctuations on the sample in a spatially resolvable manner, and it is therefore necessary to simultaneously realize the above-mentioned necessary conditions (microscopic optical system for obtaining spatial resolution that satisfies conditions A and B).

[0030] However, if the aperture of the pinhole placed at the focal position behind the first lens (wavenumber space focal plane: due to scattering angle restriction (condition B)) is narrowed, the image of the sample on the CCD will become blurred due to the principles of optics. In other words, condition B, which is necessary for observing fluctuations, and the condition B, which is necessary for ensuring spatial resolution in optical microscope observation, compete with each other and result in a trade-off.

[0031] In fact, in Non-Patent Document 1, a pinhole with a small diameter (several hundred μm) is placed at the focal position behind the first lens, and for the above reason, the spatial resolution of the fluctuation microscope is limited to approximately several hundred μm. At the time when the technology of Non-Patent Document 1 was being developed, even though it was known that a small diameter pinhole placed behind the first lens deteriorates the spatial resolution of the microscopic optical system, the focus was solely on achieving condition B, and the necessity of condition A was not known.

[0032] In fact, when Non-Patent Document 1 was written, the authors recognized that a spatial resolution of 500 μm was not sufficient for actual physical property research, etc. However, the only solutions they could think of were to increase the microscope magnification or enlarge the corners of the lens that initially focuses the scattered light.

[0033] 1 is a functional block diagram of a fluctuation microscope 1 described in Non-Patent Document 1 as a comparative example of the present invention. The pinholes PH1 and PH2 of the fluctuation microscope 1 are installed at the rear focal points of the first lens 12 and the third lens 20, respectively. This is intended to address the scattering angle limitation (condition B), but not the scattering volume limitation (condition A). In other words, Non-Patent Document 1 does not recognize the need for the scattering volume limitation (condition A), and does not install a pinhole that fulfills this role.

[0034] Furthermore, the integrated magnification of the microscopic optical system calculated from the focal length of the lens used is 300 / 120 = 2.5 times, and since the CCD camera (640 × 480 pixels, actual size 12 mm × 10 mm, pixel size approximately 20 μm) is used, P / (M × λ) = 16, which does not satisfy the necessary condition for the scattering volume limitation (condition A) due to the CCD pixel size, which will be described later, P / (M × λ) < 15 (P / M is 15 times the wavelength of the incident light or less).

[0035] That is, the pinholes PH1 and PH2 used in Non-Patent Document 1 are both placed at focal positions (wavenumber space focal planes) behind the first lens 12 and the third lens 20, and their sole role is to satisfy condition B.

[0036] In response to this, the present inventors have devised a method for observing scattered light from each point on a sample independently and simultaneously at all points, while ensuring sufficient spatial resolution in the optical microscope optical system and satisfying the above two conditions A and B, without installing small-diameter pinholes at the focal positions of the two lenses in the microscopic optical system.

[0037] To satisfy the requirement of "scattering volume limitation" (condition A), each imaging element placed at the focal point (real space focal plane) of the 2×nth lens is considered to be a virtual pinhole. In other words, in an optical microscope optical system, a magnified image of the sample is formed on each element of the imaging device, so the scattering volume at each point on the sample is automatically equal to the volume (projected area) multiplied by the integrated magnification of the optical system on each element of the imaging element. Therefore, it is most desirable for this converted volume (scattering volume) on the sample to be equal to or smaller than the wavelength of the incident light. Simply put, to satisfy condition A, it is desirable to use a high-magnification objective lens.

[0038] As a result of extensive research, the inventors have found that in order to satisfy condition A, it is desirable that the following condition be met. In this specification, this is defined as the optimal condition for satisfying condition A: 0.1<P / (M×λ)<1.1 or 0.1λ<P / M<1.1λ, where P is the pixel size (pixel size refers to the length of one side of a pixel; if the lengths of the sides are different, the length of the longest side is used as the pixel size), M is the integration magnification, and λ is the wavelength of the scattered light. The basis for this will be explained below.

[0039] As will be described in detail later, the most preferable condition for scattering volume limitation is as follows: P / (M×λ)<1 or P / M<λ Here, even if P / M is made smaller than λ, the effect of scattering volume limitation does not change any more. On the other hand, the total amount of scattered light measured decreases in proportion to the scattering volume (the cube of (scattering volume limit length P / M)). Therefore, making P / M too small is a disadvantage in terms of the total amount of scattered light. For these reasons, it is most preferable that the scattering volume limit length P / M is close to λ.

[0040] (Lower limit of optimal condition) Considering practicality, it is desirable to ensure that the total amount of scattered light is 1 / 1000 or more of that when P / M = λ. Therefore, the condition for determining the lower limit of P / M should be 0.1λ<P / M.

[0041] (Upper limit of optimal conditions) As will be seen in the examples (10x to 50x2x) described later, if the most favorable conditions for scattering volume limitation are not met and P / (M x λ) < 1 or P / M < λ, the dynamic range of observation will narrow and the observed image will become more distorted (noise-like). However, if the dynamic heterogeneity of the substance being measured (the difference in observed relaxation time) is greater than the noise, there will be no major problems even if P1 / (M x λ) ≥ 1 or P1 / M ≥ λ.

[0042] From a practical standpoint, observation can be performed with sufficiently high accuracy as long as λ is within a range of approximately 10% larger than P / M. Therefore, it is desirable that the upper limit of P / M be P / M<1.1λ.

[0043] In view of the above, in this specification, the optimum condition for satisfying condition A is defined as follows: 0.1<P / (M×λ)<1.1 or 0.1λ<P / M<1.1λ.

[0044] The following variations are defined as scattering volume limiting conditions.

[0045] (Necessary Condition) The following condition is the minimum necessary condition for satisfying condition A while satisfying α>1 / 10, where α is the ratio between the vibrational component and the non-vibrational component of the scattered light to be detected. In this specification, this is defined as the necessary condition for satisfying condition A: P / (M×λ)<15 or P / M<15λ

[0046] Based on the above idea, the scattering volume limiting condition related to P has the following variations:

[0047] A preferable scattering volume limiting condition is characterized by satisfying the relationship P / M<10λ as a condition for satisfying α>1 / 5.

[0048] A more preferable scattering volume limiting condition is characterized in that the condition of α>1 is satisfied by satisfying the relationship P / M<5λ.

[0049] The most preferable scattering volume limiting condition is characterized by satisfying the relationship P / M<λ as the condition for satisfying α>5.

[0050] In order to simultaneously satisfy the "scattering angle (spread) limitation" (Condition B) and improve the spatial resolution of the microscopic optical system to approximately the wavelength, it is not possible to place a small-diameter pinhole at the focal position (wavenumber-space focal plane) of the (2n+1)th lens. The inventors have discovered that these two conditions can be simultaneously achieved by using an objective lens with as small a numerical aperture (hereinafter referred to as NA) as possible instead of a small-diameter pinhole.

[0051] On the other hand, since an objective lens with a small NA generally has a low magnification, it competes with condition A and is a trade-off. For this reason, the following methods can be used to achieve condition B: (a) Use an objective lens with a low light-gathering efficiency (small NA) even at high magnification; (b) Use an objective lens with a small NA at low magnification and a high-magnification imaging lens / optical system; or (c) Use an intermediate variable magnification lens barrel, which is an option for microscopes, in combination. The required condition formula is originally the scattering angle θ ｋ It depends on, but approximately, Δq / q ∼ 2 sin θ ｋ = 2 × NA where q is the scattering vector and is defined by q = (4π / λ) sin θk.

[0052] If condition B is not satisfied, ambiguity (such as error bars) appears mainly in the observed values ​​on the time axis. The impact of this can be evaluated by analyzing the relaxation time histogram and distribution of each pixel (see Examples 10x to 50x 2x). Therefore, just as with condition A, even if condition B is not satisfied, but not strictly satisfied, it does not immediately mean that observation is no longer possible. In other words, there is no problem as long as the dynamic heterogeneity of the substance to be measured (the difference in observed relaxation times) is greater than the ambiguity.

[0053] From the above, the necessary and optimal conditions for satisfying condition B are determined as follows: Δq / q ∼ 2 sin θ ｋ = 2 × NA < 1.2 (±60%). Therefore, the necessary condition to satisfy condition B is NA < 0.6 Δq / q ~ 2 sin θ ｋ Calculate the optimum condition based on = 2 x NA < 0.2 (±10%). Therefore, the optimum condition to satisfy condition B is NA < 0.1

[0054] Furthermore, as a condition C, in order to make the fluctuation microscope practical, it was necessary to significantly improve the speed of numerically calculating the characteristic time of fluctuations from the brightness of each pixel. In contrast, in the present invention, by using, for example, an NVIDIA GPU package, the time required to calculate one 256 x 128 pixel fluctuation microscope image using 4096 frames of raw image data time axis can be reduced to approximately 30 seconds or less. This is a significant improvement compared to the fluctuation microscope described in Non-Patent Document 1, which required approximately two days to process one image.

[0055] 2 is a functional block diagram of a spatiotemporal structure imaging device 2 according to a first embodiment. The spatiotemporal structure imaging device 2 includes an irradiation light source 10, a sample stage 11, a first lens 12, a second lens 13, an imaging device 14, and a signal analysis device 15.

[0056] The illumination light source 10 irradiates the sample S1 with illumination light L1. The illumination light L1 is preferably monochromatic, coherent, single-mode laser light.

[0057] The sample S1 to be observed is placed on the sample stage 11. Unless otherwise specified, the sample S1 in this specification is assumed to have a finite three-dimensional size and to have dynamic heterogeneity in each internal region. In other words, the sample S1 has a certain extent both spatially and temporally. Observing this requires both spatial resolution and temporal resolution. Non-limiting examples of the sample S1 include liquid crystal, gel, glass, solution, adhesive, food, medicine, and body fluid.

[0058] The sample stage 11 may have a predetermined fixed angle between the illumination light L1 and the sample S1 (hence, the scattering angle of the scattered light L2 from the sample S1 that is incident on the first lens 12), or the angle between the illumination light L1 and the sample S1 may be variable. In the latter case, by appropriately setting the angle between the illumination light L1 and the sample S1 depending on the purpose, it is possible to observe the scattered light L2 scattered at a desired scattering angle.

[0059] The sample may be supported by any suitable supporting means other than the sample stage, and the sample stage is not essential.

[0060] The first lens 12 is disposed behind the sample stage 11. The first lens 12 is composed of a convex lens. The first lens 12 corresponds to an objective lens in a general optical microscope with an infinity corrected optical system.

[0061] Illumination light L1 from the illumination light source 10 is scattered by the sample S1 to become scattered light L2. Of the scattered light L2 scattered in various directions, that having a predetermined scattering angle according to the angle between the illumination light L1 and the sample S1 is incident on the first lens 12. Scattered light emitted from a point on the sample S1 becomes parallel light after passing through the first lens 12. According to the principles of geometric optics, the area behind the first lens 12 (and in front of the second lens 13) is wave number space (Fourier space).

[0062] The second lens 13 is disposed behind the first lens 12. The second lens 13 is also configured as a convex lens, similar to the first lens 12. The second lens 13 corresponds to an imaging lens in a general optical microscope with an infinity corrected optical system.

[0063] The scattered light L2 that passes through the first lens 12 is incident on the second lens 13. The area behind the second lens 13 is real space. The light scattered from each point on the sample S1 travels along the optical path described above and is imaged at each pixel of the imaging device 14. Therefore, the imaging device 14 captures a real image of each point on the sample S1 for each pixel.

[0064] The imaging device 14 is disposed behind the second lens 13. The imaging device 14 receives and captures the scattered light L2 that has passed through the second lens 13 on a pixel-by-pixel basis, converts the captured light into a signal such as an electrical signal, and outputs the signal. For example, the imaging device 14 is a high-speed camera such as a CCD camera. As a non-limiting example, the imaging device 14 is a CCD camera with a pixel size of 20 μm×20 μm, a pixel count of 1024×1024, and a frame rate of 1,000,000 frames / second.

[0065] The scattered light L2 scattered from each region of the sample S1 is incident on each pixel of the image capture device 14 in a one-to-one correspondence. The image capture device 14 outputs information about the scattered light L2 scattered from each region of the sample S1 (i.e., the actual image of each region) as a time-series signal (e.g., a time-series electrical signal) for each pixel. Such a signal has spatial resolution and temporal resolution with respect to the dynamic inhomogeneity inside the sample S1. The signal output from the image capture device 14 is incident on the signal analyzer 15.

[0066] The signal analyzer 15 receives a group of time-series signals of scattered light from each point of the sample S1 as raw data from the imaging device 14. As a non-limiting example, these signals are provided as 8-bit bmp data. The signal analyzer 15 converts these signals into time-series data of brightness and calculates the autocorrelation function of the scattered light for each pixel. Next, the signal analyzer 15 calculates the relaxation time from the calculated autocorrelation function. Finally, the signal analyzer 15 visualizes the calculated relaxation time, for example, by color mapping. In this way, the dynamic heterogeneity inside the sample S1 can be visualized with spatial and temporal resolution.

[0067] The autocorrelation function is a measure of how closely a signal matches a time-shifted version of itself, expressed as a function of the magnitude of the time shift, t. In other words, the autocorrelation function is a function that expresses the cross-correlation of a signal with itself. The autocorrelation function I(t) is generally defined by the following equation: where T is the observation time, N is the total number of observations, and A ｉThe subscript i indicates the ith observation data. Also, Δt is the interval time between data observations, so t = jΔt.

[0068] The autocorrelation function usually decays exponentially with time. Therefore, the autocorrelation function I(t) is expressed as In this case, τ is called the relaxation time. Intuitively, the system can be thought of as remaining in a nearly constant state for the relaxation time τ. Therefore, the shorter the relaxation time, the faster the system moves in time, and conversely, the longer the relaxation time, the slower the system moves in time.

[0069] Any suitable computational method may be used to determine the relaxation time from the autocorrelation function, including, by way of non-limiting example, fitting or harmonic averaging.

[0070] In the fitting method, the relaxation time is derived by fitting the autocorrelation function. As mentioned above, the autocorrelation function has an exponential function form, so the fitting is performed using an exponential function.

[0071] The harmonic mean method calculates the relaxation time by integrating the autocorrelation function of the scattered electric field, and is often used to quantify the average relaxation time in highly polydisperse systems, such as polymers, independent of the shape of the autocorrelation function.

[0072] As described above, it is considered that the shorter the relaxation time, the faster the system moves in time, and conversely, the longer the relaxation time, the slower the system moves in time, so the dynamic heterogeneity of the system can be visualized by color mapping the relaxation time of the signal for each pixel of the imaging device 14. For example, pixels with longer relaxation times may be represented by a color with a longer wavelength, and conversely, pixels with shorter relaxation times may be represented by a color with a shorter wavelength.

[0073] It should be noted that visualization of relaxation times is not limited to color mapping, and any suitable visualization technique may be used, such as a heat map, a histogram, a bubble chart, a 3D display, or an animation.

[0074] 3 is a schematic diagram illustrating the operation of the spatiotemporal structure imaging device 2 described above. Regions R1, R2, R3, R4, and R5 of the sample S1 each have a different dynamic state. Scattered light from each of these regions is received by pixels P1, P2, P3, P4, and P5 of the imaging device 14, respectively, and converted into electrical signals. These electrical signals are sent to the signal analysis device 15. The signal analysis device 15 calculates the autocorrelation function of the scattered light for each pixel, calculates the relaxation time from the autocorrelation function, and visualizes the respective relaxation times using color mapping CM1, color mapping CM2, color mapping CM3, color mapping CM4, and color mapping CM5.

[0075] (Limitation on Scattering Volume) The spatiotemporal structure imaging device 2 incorporates an expanded concept of dynamic light scattering (DLS). That is, the spatiotemporal structure imaging device 2 observes intensity fluctuations due to interference in actual images of each region of the sample S1 (scattered light incident on each pixel of the imaging device 14), and obtains information on dynamic heterogeneity from the observed images. In this case, if the scattering volume (the volume of each region in the sample S1) is large compared to the wavelength of the scattered light L2, the DC component in the signal increases, resulting in a reduced dynamic range of the signal. Therefore, it is necessary to appropriately limit the scattering volume.

[0076] However, in the conventional fluctuation microscope developed by the present inventors, the necessity of limiting the scattering volume was not recognized, and the scattering volume limit could not be implemented.

[0077] In response to this, the inventors have realized that the pixel size of the image capture device 14 plays the role of a pinhole as an optical element. Specifically, the inventors have found that the scattering volume limitation can be satisfied by satisfying the following condition (a necessary condition for the scattering volume limitation) where P1 is the pixel size of the image capture device 14, M is the integrated magnification determined by the first lens 12 and the second lens 13, and λ is the wavelength of the scattered light L2, and α is the ratio between the vibrational component and the non-vibrational component of the detected scattered light.

[0078] As a non-limiting example, when a second harmonic YAG laser (λ=0.532 μm) is used as the irradiation light, by setting P1=20 μm and M=50 times, the following relationship is obtained: P1 / M=20 μm / 50=0.4 μm<0.532 μm, and the condition (3) is satisfied.

[0079] Furthermore, the inventors have found that the scattering volume restriction can be more strictly satisfied by setting P1 / M<λ as the condition for satisfying α>5 (optimal condition for scattering volume restriction).

[0080] Based on the above idea, the scattering volume limiting condition related to P1 has the following variations.

[0081] The spatiotemporal structure imaging device 2 of an embodiment is characterized in that it satisfies the relationship (3).

[0082] The spatiotemporal structure imaging apparatus 2 of the preferred embodiment is characterized in that it satisfies the relationship P1 / M<10λ as the condition for satisfying α>1 / 5.

[0083] The spatiotemporal structure imaging apparatus 2 of a more preferred embodiment is characterized in that it satisfies the relationship P1 / M<5λ as the condition for satisfying α>1.

[0084] In the above description of the space-time structure imaging device 1, it was stated that, when considering actual use of the device, it is most preferable that the scattering volume limit length P / M be near λ. This also applies to the relationship between P1 / M and λ of the space-time structure imaging device 2. In other words, when considering actual use of the device, it is most preferable that P1 / M be near λ.

[0085] As described above, the optimal condition for scattering volume limitation is P1 / M<λ. Here, if the optimal scattering volume limitation condition P1 / (M×λ)<1 or P1 / M<λ is satisfied, the effect of scattering volume limitation will not change any more even if P1 / M is made smaller than λ. On the other hand, the total amount of scattered light measured decreases in proportion to the scattering volume (the cube of (scattering volume limit length P1 / M)). Therefore, making P1 / M too small is a disadvantage in terms of the total amount of scattered light. For these reasons, it is most preferable that the scattering volume limit length P1 / M is close to λ.

[0086] (Lower limit value of optimal condition) Considering practicality, it is desirable to ensure that the total amount of scattered light is 1 / 1000 or more compared to when P1 / M = λ. Therefore, the condition for determining the lower limit value of P1 / M is desirably 0.1λ<P1 / M.

[0087] (Upper limit of optimal conditions) As will be seen in the examples (10x to 50x2x) described later, if the most favorable conditions for scattering volume limitation are not met, and P1 / (M x λ) < 1 or P1 / M < λ, the accuracy of measuring the characteristic time of the movement will decrease. However, this does not immediately mean that observation is impossible. Specifically, if P1 / (M x λ) ≥ 1 or P1 / M ≥ λ, the dynamic range of observation will narrow, and the observed image will become more distorted (like noise). However, if the dynamic heterogeneity of the substance being measured (the difference in observed relaxation time) is greater than the noise, there will be no major problems even if P1 / (M x λ) ≥ 1 or P1 / M ≥ λ.

[0088] From a practical standpoint, observation can be performed with sufficiently high accuracy as long as λ is within a range of approximately 10% larger than P1 / M. Therefore, it is desirable that the condition for determining the upper limit of P1 / M be P1 / M<1.1λ.

[0089] In view of the above, in this specification, the optimum condition for satisfying condition A is defined as follows: 0.1<P1 / (M×λ)<1.1 or 0.1λ<P1 / M<1.1λ

[0090] In this way, the scattering volume is limited using the relationship between pixel size and integration magnification, which is one of the novel features of this embodiment compared to the prior art.

[0091] (Limitation on Scattering Angle) If the scattering angle range of the scattered light L2 from the sample S1 that enters the imaging device 14 is too wide, the wavenumber space of the observation target will not be sharply defined, and the observed relaxation time will be ambiguous. To prevent this, it is necessary to impose an appropriate limitation on the scattering angle range of the scattered light L2 that enters the imaging device 14, so that only the light that enters approximately parallel to the optical axes of the first lens 12 and the second lens 13 is allowed to enter each pixel of the imaging device 14.

[0092] The conventional fluctuation microscope developed by the inventors limits the scattering angle by placing a pinhole on the wavenumber-space focal plane of the optical system. However, for optical microscope observation, narrowing the aperture of the pinhole has the disadvantage of reducing the spatial resolution of the observation.

[0093] In response to this, the inventors realized that the scattering angle limitation can be satisfied by sufficiently reducing the numerical aperture of the first lens 12. Specifically, when the numerical aperture of the first lens 12 from the object is NA, Δq / q ∼ 2 sinθ ｋ Calculate the optimum conditions based on the following: = 2 × NA < 1.2 (±60%)

[0094] From this, the inventors have found that the scattering angle limitation can be satisfied by setting NA<0.6 (4) (a necessary condition for scattering angle limitation), where the numerical aperture NA and scattering vector q are respectively given by NA=n sin θ ａ (5) q=(4π / λ)sinθ ｋ (6)

[0095] Furthermore, Δq / q ∼ 2 sinθ ｋ Calculate the optimum conditions based on the following: = 2 × NA < 0.2 (±10%)

[0096] As a result, the inventors have found that the scattering angle limit can be more strictly satisfied by setting NA<0.1 (optimum condition regarding scattering angle limit).

[0097] The spatiotemporal structure imaging device 2 of an embodiment is characterized in that it satisfies the relationship of formula (4).

[0098] In order to obtain the spatiotemporal structure imaging device 2 of the preferred embodiment, Δq / q ∼ 2 sin θ ｋ Calculate the optimum conditions based on the following: = 2 × NA < 0.8 (±40%)

[0099] As a result, the spatiotemporal structure imaging device 2 of the preferred embodiment is characterized by satisfying the relationship NA<0.4.

[0100] In order to obtain the spatiotemporal structure imaging apparatus 2 of a more preferred embodiment, Δq / q ∼ 2 sinθ ｋ Calculate the optimum conditions based on the following: = 2 × NA < 0.4 (±20%)

[0101] As a result, the spatiotemporal structure imaging device 2 of the more preferred embodiment is characterized by satisfying the relationship NA<0.2.

[0102] In order to obtain the most preferable embodiment of the spatiotemporal structure imaging device 2, the optimum conditions are calculated based on the following: Δq / q ∼ 2 sin θk = 2 × NA < 0.2 (±10%).

[0103] As a result, the most preferred embodiment of the spatiotemporal structure imaging device 2 is characterized by satisfying the relationship NA<0.1.

[0104] In this way, the scattering angle is limited using the relationship between the numerical aperture and the scattering vector, which is one of the novel features of this embodiment compared to the prior art.

[0105] 1 is a functional block diagram of a conventional fluctuation microscope 1 as a comparative example to the embodiment. The fluctuation microscope 1 includes a first pinhole PH1, a second pinhole PH2, a third lens 20, and a fourth lens 21 in addition to the configuration of the spatiotemporal structure imaging device 2 in FIG.

[0106] The third lens 20 and the fourth lens 21 are both formed as convex lenses. The third lens 20 is disposed behind the second lens 13. The fourth lens 21 is disposed behind the third lens 20. The space between the third lens 20 and the fourth lens 21 is a wave number space. The space behind the fourth lens 21 is a real space.

[0107] The first pinhole PH1 is disposed between the first lens 12 and the second lens 13, on the focal plane of the first lens 12 and the second lens 13. The second pinhole PH2 is disposed between the third lens 20 and the fourth lens 21, on the focal plane of the third lens 20 and the fourth lens 21.

[0108] The first pinhole PH1 and the second pinhole PH2 are both tangent to the wavenumber space focal position, and by narrowing the aperture diameter of the pinholes, the incident light is restricted so that only light that is incident approximately parallel to the optical axis of the lens is allowed to enter each pixel of the imaging device 14. In this way, the first pinhole PH1 and the second pinhole function to satisfy the scattering angle restriction described above.

[0109] However, the presence of such a small-diameter pinhole placed at the wavenumber-space focus is a fatal cause of deterioration in the spatial resolution of an optical microscope.

[0110] In contrast, the spatiotemporal structure imaging device 2 of this embodiment does not have a pinhole, and can satisfy the scattering volume restriction and scattering angle restriction with only the optical configuration shown in Fig. 2. In this respect, the spatiotemporal structure imaging device 2 has a great advantage over the fluctuation microscope 1.

[0111] As described above, according to this embodiment, it is possible to realize a high-performance space-time structure imaging device that satisfies the required scattering volume limitations and scattering angle limitations while using a simple optical system.

[0112] 4 is a functional block diagram of a spatiotemporal structure imaging device 3 according to a second embodiment. The spatiotemporal structure imaging device 3 includes an intermediate magnification changer 16 disposed between the first lens 12 and the second lens 13, in addition to the configuration of the spatiotemporal structure imaging device 2 in FIG. 1. The other configuration of the spatiotemporal structure imaging device 3 is the same as the configuration of the spatiotemporal structure imaging device 2.

[0113] The intermediate magnification changer 16 is composed of, for example, a single lens, a variable magnification lens, or a set of lenses that are switchable among a plurality of lenses.

[0114] The intermediate magnification changer 16 can be combined with the first lens 12 and the second lens 13 to change the integrated magnification of the entire optical system.

[0115] Regarding the scattering volume restriction, in the above example, the scattering volume condition was met by setting P1 = 20 μm and M = 50x (without an intermediate magnification changer) for irradiation light of λ = 0.532 μm (P1 / M = 20 μm / 50 = 0.4 μm < 0.532 μm). On the other hand, if the integrated magnification of the optical system consisting of the first lens 12 and the second lens is 20x, by using an intermediate magnification changer 16 that further doubles this, the overall integrated magnification can be made 20x x 2 = 40x. In this case, too, P1 / M = 20 μm / (20 x 2) = 0.5 μm < 0.532 μm, and the scattering volume restriction is met.

[0116] As described above, according to this embodiment, the intermediate magnification changer increases the degree of freedom of the integrated magnification of the spatiotemporal structure imaging device.

[0117] 5 is a functional block diagram of a space-time structure imaging device 4 according to a third embodiment. The space-time structure imaging device 4 includes a third lens 17 and a fourth lens 18 in addition to the configuration of the space-time structure imaging device 2 in FIG. 1. The other configuration of the space-time structure imaging device 4 is common to the configuration of the space-time structure imaging device 2.

[0118] The third lens 17 and the fourth lens 18 are both formed as convex lenses. The third lens 17 is disposed behind the second lens 13. The fourth lens 18 is disposed behind the third lens 17. The space between the third lens 17 and the fourth lens 18 is a wave number space. The space behind the fourth lens 18 is a real space.

[0119] The installation positions of the third lens 17 and the fourth lens 18 may be movable along the optical axes of the first lens 12 and the second lens 13 .

[0120] The third lens 17 and the fourth lens 18 collect the light emitted from the second lens 13 and make it incident on the imaging device 14. If the third lens 17 and the fourth lens 18 are not present, the installation position of the imaging device 14 is restricted by the first lens 12 and the second lens 13. Conversely, if the third lens 17 and the fourth lens 18 are present, the installation position of the imaging device 14 can be determined independently of the first lens 12 and the second lens 13. In particular, if the installation positions of the third lens 17 and the fourth lens 18 are movable, the installation position of the imaging device 14 also becomes movable.

[0121] According to this embodiment, the degree of freedom in the installation position of the imaging device is increased, and therefore the degree of freedom in the configuration of the spatiotemporal structure imaging device is increased.

[0122] [Fourth embodiment] Fig. 6 is a functional block diagram of a spatiotemporal structure imaging device 5 according to a fourth embodiment. In addition to the configuration of the spatiotemporal structure imaging device 4 shown in Fig. 5, the spatiotemporal structure imaging device 4 includes a pinhole array PH10 in which one or more pinholes designed at a real space focus between the second lens 13 and the third lens 17 are arranged. The pinhole array PH10 may be a pinhole array whose aperture diameter or open / closed state can be controlled mechanically or electronically. The other configuration of the spatiotemporal structure imaging device 5 is common to that of the spatiotemporal structure imaging device 4.

[0123] According to this, even if the pixel size of the imaging device does not satisfy the condition of the scattering volume limitation, the condition of the scattering volume limitation can be satisfied by optimizing the maximum value of each pinhole size of the pinhole array PH10. Specifically, when the maximum value of each pinhole size of the pinhole array PH10 is P2, the integrated magnification from the first lens 12 to the pinhole array PH10 is M, and the wavelength of the scattered light L2 is λ, the ratio of the vibrational component to the non-vibrational component of the detected scattered light is α, and the condition of α>1 / 10 is satisfied by satisfying the following: P2 / M<15λ (7) (a necessary condition for the scattering volume limitation).

[0124] Furthermore, the inventors have found that the scattering volume restriction can be more strictly satisfied by setting P2 / M<λ as the condition for satisfying α>5 (optimal condition for scattering volume restriction).

[0125] Based on the above idea, the scattering volume limiting condition related to P2 has the following variations.

[0126] The spatiotemporal structure imaging device 5 of an embodiment is characterized in that it satisfies the relationship of formula (7).

[0127] The spatiotemporal structure imaging apparatus 5 of a preferred embodiment is characterized in that it satisfies the relationship P2 / M<10λ as the condition for satisfying α>1 / 5.

[0128] A more preferred embodiment of the spatiotemporal structure imaging apparatus 5 is characterized in that the condition for satisfying α>1 is that the relationship P2 / M<5λ is satisfied.

[0129] In the above description of the space-time structure imaging device 1, it was stated that, when considering actual use of the device, it is most preferable that the scattering volume limit length P / M be in the vicinity of λ. This also applies to the relationship between P / M and λ in the space-time structure imaging device 5. In other words, when considering actual use of the device, it is most preferable that P / M be in the vicinity of λ.

[0130] The most preferred embodiment of the spatiotemporal structure imaging apparatus 5 is characterized in that it satisfies the relationship P2 / M<λ as the condition for satisfying α>5.

[0131] As described above, the optimal condition for scattering volume limitation is P2 / M<λ. Here, if the optimal scattering volume limitation condition P2 / (M×λ)<1 or P2 / M<λ is satisfied, the effect of scattering volume limitation will not change any more even if P2 / M is made smaller than λ. On the other hand, the total amount of scattered light measured decreases in proportion to the scattering volume (the cube of (scattering volume limit length P2 / M)). Therefore, making P2 / M too small is a disadvantage in terms of the total amount of scattered light. For these reasons, it is most preferable that the scattering volume limit length P2 / M is close to λ.

[0132] (Lower limit value of optimal condition) Considering practicality, it is desirable to ensure that the total amount of scattered light is 1 / 1000 or more compared to when P2 / M = λ. Therefore, the condition for determining the lower limit value of P2 / M is desirably 0.1λ<P2 / M.

[0133] (Upper limit of optimal conditions) As will be seen in the examples below (10x to 50x2x), if the most favorable conditions for scattering volume limitation are not met, and P2 / (M x λ) < 1 or P2 / M < λ, the accuracy of measuring the characteristic time of movement will decrease. However, this does not immediately mean that observation is impossible. Specifically, if P2 / (M x λ) ≥ 1 or P2 / M ≥ λ, the dynamic range of observation will narrow, and the observed image will become more distorted (like noise). However, if the dynamic heterogeneity of the substance being measured (the difference in observed relaxation time) is greater than the noise, there will be no major problems even if P2 / (M x λ) ≥ 1 or P2 / M ≥ λ.

[0134] From a practical standpoint, observation can be performed with sufficiently high accuracy as long as λ is within a range of approximately 10% larger than P2 / M. Therefore, it is desirable that the condition for determining the upper limit of P2 / M be P2 / M<1.1λ.

[0135] In view of the above, in this specification, the optimum condition for satisfying condition A is defined as follows: 0.1<P2 / (M×λ)<1.1 or 0.1λ<P2 / M<1.1λ

[0136] The spatiotemporal structure imaging device 5 is equipped with a pinhole array PH10, but this pinhole array PH10 does not degrade the spatial resolution of the optical microscope, unlike the small-diameter pinholes PH1 and PH2 placed at the wavenumber space focus of the conventional fluctuation microscope 1. As with the other embodiments described above, the spatiotemporal structure imaging device 5 also realizes scattering volume limitation using the relationship between pixel size and integrated magnification, and realizes scattering angle limitation using NA.

[0137] According to this embodiment, it is possible to introduce a pinhole that does not affect the spatial resolution of the optical microscope, thereby further increasing the degree of freedom in the configuration.

[0138] [Example 1]

[0139] 7 shows the results of visualizing the dynamic inhomogeneity of a sample (E44 liquid crystal) by color mapping using the spatiotemporal structure imaging device of the present disclosure. (a) Pure E44 liquid crystal, (b) E44 liquid crystal gel (LCG), and (c) E44 liquid crystal polymer.

[0140] As shown in Figure 7, the spatiotemporal structure imaging device of the present disclosure reveals that even with the same E44, the dynamic heterogeneity varies depending on the molecular structure and orientation order, such as between pure liquid crystal, liquid crystal gel, and liquid crystal polymer.

[0141] Pure nematic liquid crystals (E44) exhibit a dynamically uniform state. In contrast, in polymerized swollen polymer liquid crystals and liquid crystal gels containing crosslinkers, dynamic heterogeneity emerges due to the sol-gel and glass transitions, and the spatiotemporal structure significantly affects the electric and mechanical properties of the liquid crystals. Until now, there has been no method for visualizing dynamic heterogeneity. However, the spatiotemporal structure imaging system allows direct experimental observation of the spatiotemporal structure (spatial morphology and temporal evolution of dynamic heterogeneity) as 2D still and dynamic images. This allows for direct in-situ characterization of dynamic heterogeneity within polymer materials. This observation can be used to observe the dynamic heterogeneity of polymer alloys with poor compatibility, which can be useful for guiding material design and performance improvement. It can also be used to observe, evaluate, and analyze changes in dynamic heterogeneity due to the cooling process and injection speed during processing such as polymer injection molding, which can be useful for improving material properties and product manufacturing.

[0142] [Embodiment 2] The spatiotemporal structure imaging device of the present disclosure can, in principle, be used to observe all substances, including gases, liquids, and solids.

[0143] Of these, solids have a large elastic modulus and fluctuations at high frequencies, making spectral analysis difficult with existing high-speed cameras (when the internal state changes while the material is uniform and transparent, as in glass transition, it may be possible to observe the solid at temperatures close to that of a liquid (high temperatures). Furthermore, SiO ２ Higher polymer glasses are more likely).

[0144] In the case of gases, it is suitable for observing the movement of suspended matter such as PM2.5, yellow sand, and water vapor (because they are slow), but in principle it is also possible to observe the fluctuations of the gas itself.

[0145] For the same reason, liquids containing molecules, clusters, particles, bubbles, etc. are also suitable for observing their space-time structure. It is also possible to record video of the changes in the space-time structure of a substance that occur immediately after changing the temperature or pressure. For example, it is also possible to record the changes in the space-time structure of a substance after applying an external field such as an electric field or light. Specific examples are given below.

[0146] (Example 1) A sample made by enclosing low-molecular-weight liquid crystal molecules, such as those used in liquid crystal displays, in a display liquid crystal cell to which an electric field can be applied has high scattering power and is suitable for observation. In this case, information related to the anchoring strength of the glass substrate, which is related to the performance of the liquid crystal cell, can also be obtained as an image. Figure 8 shows the image obtained in this case.

[0147] In areas with weak anchoring strength, the extrapolation length is longer, resulting in a slower relaxation time, while in areas with high anchoring strength, the relaxation time is faster. This is displayed as image information, and the distribution of differences in anchoring strength can be analyzed and evaluated from the distribution of dynamic heterogeneity.

[0148] (Example 2) In sake, alcohol molecules form transient (dynamic) clusters on the nanometer scale, and it is said that the size and distribution of the alcohol clusters are related to the taste and richness of the sake. The spatiotemporal structure of the clusters can be visualized using a spatiotemporal structure imaging device. In fact, clear differences emerge when comparing daiginjo sake, ginjo sake, and junmai sake from the same brewery. This type of observation can also be used to study the sake brewing process, inspect products, and record differences depending on the year of production. Figure 9 shows the image obtained.

[0149] (Example 3) In white wine, changes appear immediately after opening, and it is said that these changes are related to the taste and body of the white wine. As with sake, these changes can be understood as transient (dynamic) changes in the clusters of alcohol molecules. A spatiotemporal structure imaging device can visualize the temporal changes in the spatiotemporal structure of the clusters. This type of observation can be used to understand the deterioration process of alcohol, storage methods, product inspection, and more. Figure 10 shows the image obtained.

[0150] (Example 4) The spatiotemporal structure imaging device can be used to confirm and inspect various chemical reaction processes. As an example of observing such a chemical reaction process, we show a polymerizable polyethylene glycol (PEG, molecular weight approximately 500) aqueous solution before and after polymerization, as well as a PEG hydrogel. It can be seen that the three aqueous solutions exhibit different dynamic heterogeneities due to the movement of PEG in water. Figure 11 shows the images obtained.

[0151] (Example 5) In biological structures such as cells and tissues, as well as in many everyday products such as foods, pharmaceuticals, and emulsions, molecular aggregates of surfactant molecules called micelles are solubilized in water due to the incompatibility between water and oil molecules. The shape and size of micelles vary depending on various conditions, including the type of surfactant, temperature, concentration, pH, and salt concentration, resulting in changes in size and morphology, such as spheres, rods, and membranes (sheets). Furthermore, the molecular aggregates themselves are constantly changing, maintaining a dynamic dissociation-association equilibrium with single molecules dispersed in the solvent, water. A spatiotemporal structure imaging device can visualize the spatiotemporal structure of these micelles. In other words, their use in observing their dispersion in brains, neurons, blood, and body fluids could be useful in medical and pharmaceutical fields. Figure 12 shows the image obtained.

[0152] (Example 6) When the shape of the micelles (molecular aggregates) is not spherical, the dynamic heterogeneity associated with the rotational motion of the molecular aggregates can be visualized by inserting a polarizing plate and measuring depolarized scattered light. The observation in Example 6 is related to the translational motion of the molecular aggregates in aqueous solution, and visualizes the dynamic heterogeneity primarily associated with the size and size distribution of the aggregates. However, this method visualizes the dynamic heterogeneity sensitively to morphological changes of the molecular aggregates, such as changes from spheres to rods to films. Figure 13 shows the image obtained.

[0153] (Example 7) When the substance being observed has a phase-separated structure of 1 μm or more, the diffusion and mobility of solute molecules near the interface can be directly observed by observing at an appropriate magnification that allows observation of the interface morphology (shape, size, dimensionality of connections, topology, etc.). Furthermore, when a surfactant localized at the interface is added, the dynamic function of the surfactant localized at the interface can also be visualized. For example, the role of membrane proteins that control the transport of biomolecules and ions in and out of cells, and differences in activity due to changes in pH, etc., can be observed. Figure 14 shows the image obtained in this case.

[0154] (Example 8) The spatiotemporal structure imaging device disclosed herein can measure the dynamic heterogeneity of a material, enabling the detection, evaluation, and analysis of the dynamic heterogeneity of the orientational order of the material (the location dependence of dynamic properties such as elasticity and viscosity) and its temporal changes. Figure 15 shows an example of a measurement in which UV light was irradiated onto a portion of a liquid crystal containing an azobenzene compound, causing the azobenzene compound present in that region to isomerize to a cis isomer, thereby changing the dynamic heterogeneity of the orientational order of the liquid crystal in that region. Before irradiation, a uniform color reflecting the rapid dynamic homogeneity was observed. When this material was partially irradiated with UV light, the spatiotemporal structure imaging device was able to record a video of the appearance of an isotropic phase in the UV-irradiated region during irradiation. It was clear that UV irradiation caused the azo dye molecules to isomerize, disrupting the liquid crystal order and inducing an isotropic phase transition, resulting in the clear observation of the resulting dynamic heterogeneity of the material. In the case of liquids, for example, even in phenomena such as drying or adhesion on the surface, there is currently no device available to observe structural changes in transparent liquid materials. Therefore, it can be seen that the information about dynamic heterogeneity obtained by the spatiotemporal structure imaging device disclosed herein is useful information about the structure of liquid materials.

[0155] (Example 9) There are no particular limitations on the factors that cause dynamic heterogeneity that can be detected, evaluated, and analyzed using the spatiotemporal structure imaging device of the present disclosure. Figure 16 shows a measurement example in which a mechanical external force is applied to a material as a factor. Using the spatiotemporal structure imaging device of the present disclosure to measure the process of uniaxially stretching a film, in-situ observation is possible under stress. It was found that the relaxation time shortens depending on the stretching speed, that the film exhibits a single relaxation behavior before stretching but expands as the stretching progresses, and that streaky dynamic heterogeneity occurs at high stretching rates. This enables an understanding of the fracture and yielding mechanisms, and can be utilized in the design and prototyping of materials with improved toughness and fracture resistance, as well as in the evaluation of films and film manufacturing processes.

[0156] (Example 10) The spatiotemporal structure imaging device can also be used to spatially observe, evaluate, and analyze chemical reaction processes. Figure 17 shows an example of a measurement of a nematic liquid crystal gel material containing a photopolymerizable material, in which light was irradiated and polymerization was initiated from the irradiated area. Before irradiation, a uniform color reflecting a rapid dynamic uniform state was observed. When this material was partially irradiated with UV light, the spatiotemporal structure imaging device was used to record a video of the progress of polymerization and hardening in the UV-irradiated area during irradiation. It can be seen that dynamic heterogeneity occurs around the irradiated area due to initiator diffusion or the progression of the polymerization reaction, resulting in a blurred interface. When forming patterns through photopolymerization, a sharp interface between the irradiated and unirradiated areas is important for increasing pattern resolution and performing fine processing. Using the spatiotemporal structure imaging device to evaluate the clarity of the dynamic heterogeneity interface allows for non-destructive and non-contact observation and evaluation of photoresist films, photofabricated structures within in-cells, and their manufacturing processes. In this way, the use of a spatiotemporal structure imaging device makes it possible to observe changes in state due to solidification reactions caused by polymerization of optically isotropic or transparent substances such as adhesives. Furthermore, similar observations of drying, solidification, crystallization, etc. on surfaces as well as bulk materials are possible.

[0157] (Example 11) Using a spatiotemporal structure imaging system, changes in physical structure accompanying chemical reactions can also be observed, evaluated, and analyzed. Figure 18 shows an example of measuring the time evolution of the spatial distribution of dynamic heterogeneity in phase separation dynamics. In composite materials containing polymers, such as polymer-dispersed liquid crystals, it is important to control the structure formation due to polymer phase separation. Using a spatiotemporal structure imaging system, we can nondestructively and noncontactly evaluate the dynamic heterogeneity of materials before, during, or after phase separation. This information can be used to design materials and manufacturing processes to obtain desirable physical structures. The upper right image in Figure 18 observes the evolution (dynamics) of fluctuations during the quenching process from miscibility to the phase-separated region. The middle right image in Figure 18 observes the difference in dynamics inside and outside the interface of the phase-separated region, as well as interfacial diffusion. The lower right image in Figure 18 shows the formation of a macroscopic phase-separated structure by mixing polystyrene into a liquid crystal, as observed with a spatiotemporal imaging system. The morphology of the phase-separated structure itself can be confirmed using a phase-contrast microscope, but a space-time imaging device can also be used to observe the dynamic heterogeneity of polystyrene molecules and liquid crystal molecules both inside and outside the interface. Here, it was observed that molecular diffusion across the interface slowed down at the interface. Such transport phenomena across interfaces are also important for biological functions such as ion channels. Furthermore, the effects of mixing surface-stabilizing molecules such as surfactants on diffusion across interfaces, as well as the control of ion and substance blocking and permeation at interfaces, can be directly visualized in experiments for transport in separation membranes, filters, molecular sieves, etc.

[0158] (Example 12) Aqueous solutions of rod-like micelles may develop orientational order at low temperatures and undergo a phase transition to a nematic phase. Observation using a space-time imaging device in the VH configuration (depolarized scattering) allows for the separation of spatial and temporal changes in the relaxation time of orientational fluctuations. In other words, if the liquid crystal orientational order is uniform across locations, the liquid crystal will exhibit dynamic uniformity, resulting in an image with a uniform color reflecting this uniformity. Otherwise, images with color contrast, featuring bright spots of different colors, will be obtained, reflecting dynamic heterogeneity. Figure 19 shows images of the dynamic heterogeneity of an 8% aqueous solution of a thermo-concentration-transition liquid crystal (SDS+DTAB) measured by depolarized (VH) scattering at temperatures near the isotropic-nematic phase transition. At higher temperatures (lower left of Figure 19), the loss of orientational order due to the isotropic-nematic phase transition results in a black image, indicating the absence of fluctuations. In particular, as the temperature decreased from just above the transition point (towards the top of Figure 19 in the image), different types of bright spots appeared in the image from the space-time imaging device, and the spatial growth of nematic-cybotactic clusters in the isotropic phase was experimentally captured for the first time as the relaxation time decreased. This material (aqueous surfactant solution) is a unique material system that exhibits a continuous isotropic-nematic phase transition, and information can be obtained that will shed light on its origin.

[0159] (Example 13) Observation using a spatiotemporal structure imaging device in VV configuration (polarization-preserving scattering) allows for the separation and observation of spatial and temporal changes in the relaxation time of concentration fluctuations in response to changes in aggregate shape, length, and cross-sectional area. In other words, if the aggregate shape and size are uniform across location, it will be dynamically uniform, resulting in an image with a uniform color reflecting this uniformity. Otherwise, an image with color contrast, featuring bright spots of different colors, will be obtained, reflecting dynamic heterogeneity. Figure 20 shows the results of polarization-preserving (VV) scattering measurements of the same liquid crystal used in Example 12. In surfactant aqueous solutions, supramolecular aggregates such as spheres, rods, and films are formed as molecular aggregates. In the case of rods and films, their length and area also change depending on temperature and concentration. The observed images show that micelle size decreases across the isotropic-liquid crystal phase transition, but micelles remain stable even in the isotropic phase (bottom panel in Figure 20). Furthermore, the random observation of bright spots of different colors indicates that there is a distribution in the shape and size of micelles, creating a dynamically heterogeneous state. The aggregates formed by such surfactants in aqueous solution are strongly related to the basic structures of living organisms (cell membranes, nerves, liposomes, vesicles, brain structures, etc.), and because these changes can be observed non-contact and non-destructively, it is clear that abnormalities and changes in biological tissues can be specifically detected in pathology, treatment, testing, etc.

[0160] The present invention has been described above based on the embodiments. These embodiments are merely examples, and it will be understood by those skilled in the art that various modifications are possible in the combination of the respective components and treatment processes, and that such modifications are also within the scope of the present invention.

[0161] For example, in the above embodiment, the dynamic heterogeneity of the sample is expressed by visualizing the relaxation time, but the present invention is not limited to this, and the dynamic heterogeneity of the sample can also be expressed using sound (expression related to the sense of hearing), texture (expression related to the sense of touch), smell (expression related to the sense of smell), etc.

[0162] Such a modification provides the same functions and effects as the embodiment.

[0163] Any combination of the above-described embodiments and modifications is also useful as an embodiment of the present invention. A new embodiment resulting from the combination has the combined effects of each of the combined embodiments and modifications.

[0164] The spatiotemporal structure imaging device according to the present disclosure can be widely applied to academic research in the field of physical properties, the manufacturing and non-destructive testing of chemical products, medicines, food, etc., the diagnosis and treatment of patients, pharmaceuticals, etc.

[0165] 1... Fluctuation microscope, 2... Space-time structure imaging device, 3... Space-time structure imaging device, 4... Space-time structure imaging device, 5... Space-time structure imaging device, 10... Illumination light source, 11... Sample stage, 12... First lens, 13... Second lens, 14... Imaging device, 15... Signal analysis device, 16... Intermediate magnification device, 17... Third lens, 18... Fourth lens, 20... Third lens, 21... Fourth lens, CM1... Color mapping, CM2... Color mapping, CM3... Color mapping, CM4... Color mapping, CM5... Color mapping, L1... Illumination light, L2... Scattered light, P1... Pixel, P2... Pixel, P3... Pixel, P4... Pixel, P5... Pixel, PH1... Pinhole, PH2... Pinhole, PH10... Pinhole array, R1...Region, R2...Region, R3...Region, R4...Region, R5...Region, S1...Sample.

Claims

1. A space-time structure imaging device comprising: a first lens that receives scattered light from an object to be observed; and a second lens that is disposed behind the first lens; and an element that has the function of limiting the scattering volume and an image sensor that receives and photographs the scattered light in pixel units, converts it into a signal, and outputs it, disposed near the real space focal point formed behind the second lens.

2. A space-time structure imaging device as described in claim 1, characterized in that P / M<15λ is satisfied, where P is the scattering volume limiting length, M is the integrated magnification determined by the lens arranged between the first lens and the element having the function of limiting the scattering volume, and λ is the wavelength of the scattered light.

3. A space-time structure imaging device as described in claim 1, characterized in that an element having the function of limiting the scattering volume is included in the imaging element, the scattering volume limit length P corresponds to the pixel size of the imaging element, and when the pixel size is P1, P1 / M<15λ.

4. A space-time structure imaging device according to claim 1, characterized in that the element having the function of limiting the scattering volume is composed of one or more pinholes, and when the pinhole size of the pinhole is P2, P2 / M<15λ.

5. A spatiotemporal structure imaging device according to any one of claims 1 to 4, characterized in that it comprises a signal analysis device that converts the signal into time series data of brightness, calculates the autocorrelation function of the scattered light for each pixel, calculates the relaxation time from the autocorrelation function, and visualizes the relaxation time.

6. A space-time structure imaging device according to claim 1, characterized in that, when the numerical aperture of the first lens from the object of observation is NA, NA<0.

6.

7. A spatiotemporal structure imaging device according to any one of claims 1 to 4, characterized in that an intermediate magnification changer is provided between the first lens and the second lens.

8. A space-time structure imaging device according to any one of claims 1 to 4, characterized in that a third lens and a fourth lens are provided behind the second lens.

9. The spatiotemporal structure imaging device according to claim 5, wherein the signal analysis device visualizes the relaxation time by color mapping.

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