Measurement apparatus and measurement method

Abstract

To provide a measuring device and a measuring method capable of separately determining a diffusion coefficient of particles contained in a fluid and an advection velocity of the fluid, and determining a shear viscosity characteristic and a temporal characteristic of a non-Newtonian fluid by on-site observation, in the measuring device formed by combining OCT and DLS.SOLUTION: A coupling optical unit that couples reflected or scattered light with reference light that is not reflected or scattered by the observation object, a detection unit that detects coupled light coupled by the coupling optical unit, and a control unit that acquires an optical coherence tomographic image of the observation object on the basis of the coupled light, the control unit records an optical coherence tomographic image of the fluid from the acquired optical coherence tomographic image of the observation object, obtains each of characteristic values representing degrees of thermal motion and advective motion of particles contained in the fluid based on the optical coherence tomographic image of the fluid, and outputs position information of each of the characteristic values in a two-dimension space and time information representing a temporal change of the characteristic value.SELECTED DRAWING: Figure 2-1

Description

[Technical Field]

[0001] The present invention relates to a measurement device and a measurement method. [Background technology]

[0002] In inkjet printing and spray painting, the state of the ink or paint needs to be appropriately changed during the process of forming an image or coating. In particular, the viscosity of the ink or paint has a significant impact on the droplet ejection state and the quality of the coating. In order to design ink and process conditions that appropriately change viscosity, it is useful to be able to measure the change in viscosity of the ink in the flow path inside or near the head, and of the ink after it has become a coating.

[0003] A known method for measuring the viscosity of ink or paint is, as defined, to sandwich the ink between parallel plates, determine the velocity and stress when the plates are moved, and calculate the viscosity based on this relationship.

[0004] Additionally, for inks containing particles such as pigments, a known method involves irradiating the particles with laser light, detecting the scattered light, and analyzing the temporal fluctuations in the intensity of the detected light. If the viscosity of the ink solvent is low, the particles move vigorously (Brownian motion), whereas if the viscosity of the ink solvent is high, the particle movement becomes slow. Because the temporal fluctuations in scattered light correspond to the intensity of the particle movement, the viscosity of the ink solvent can be measured by optical observation. This measurement method is generally known as dynamic light scattering.

[0005] Patent Document 1 discloses an observation device that combines optical coherence tomography (OCT) and dynamic light scattering (DLS) for the purpose of observing the change over time in particle diffusion coefficient in the depth direction from the gas-liquid surface for ink in a glass capillary that simulates the nozzle of an inkjet head, and discloses a means for observing the state in which the solvent evaporates from the gas-liquid surface and the ink viscosity increases with a distribution. Summary of the Invention [Problem to be solved by the invention]

[0006] However, in an observation device (an example of a measurement device) that combines OCT and DLS, when a fluid has a flow, such as when inkjet ink (an example of a fluid) flows through a channel or when convection occurs after forming a coating, the component of motion of the particles contained in the fluid is superimposed on the component of thermal motion of the particles, making it difficult to simply determine the diffusion coefficient using dynamic light scattering. It is known that viscosity fluctuates depending on the magnitude of the difference in ink flow speed (shear rate), and this cannot be measured with non-Newtonian inks.

[0007] The present invention has been made in view of the above, and aims to provide a measuring device that combines OCT and DLS, which can separately determine the diffusion coefficient of particles contained in a fluid and the velocity at which the fluid is advected, thereby making it possible to determine the shear viscosity characteristics and temporal characteristics of a non-Newtonian fluid through in-situ observation. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems and achieve the object, the present invention provides a system comprising: a light source that emits irradiation light; an irradiation optical unit that irradiates at least a portion of the irradiation light emitted from the light source onto an observation object, which is a fluid containing particles that reflect or scatter at least the irradiation light; a combination optical unit that combines light that is the irradiation light reflected or scattered by the observation object with reference light that is at least a portion of the irradiation light emitted from the light source and is not reflected or scattered by the observation object; a detection unit that detects the combined light combined by the combination optical unit; and a control unit that acquires an optical coherence tomographic image of the observation object based on the combined light detected by the detection unit, wherein the control unit records the optical coherence tomographic image of the fluid from the acquired optical coherence tomographic image of the observation object, and determines characteristic values ​​that represent the degree of thermal motion and advection motion of the particles contained in the fluid based on the optical coherence tomographic image of the fluid, and outputs position information of each of the characteristic values ​​in at least two-dimensional space and time information that represents changes in the characteristic values ​​over time. [Effects of the Invention]

[0009] According to the present invention, in a measuring device that combines OCT and DLS, the diffusion coefficient of particles contained in a fluid and the velocity at which the fluid is advected can be determined separately, and the shear viscosity characteristics and temporal characteristics of a non-Newtonian fluid can be determined by in-situ observation. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a flowchart showing an example of a flow for determining the non-Newtonian characteristics of a fluid to be measured by a measurement method of a measurement device according to this embodiment. [Figure 2-1] FIG. 2-1 is a diagram for explaining an example of a hardware configuration used in the part for preparing a learning model in the measurement method of the measurement device according to the present embodiment. [Figure 2-2] FIG. 2-2 is a block diagram showing an example of a hardware configuration of a processing unit included in the measuring device according to this embodiment. [Figure 3] FIG. 3 is a diagram showing an example of a combination of a suspension containing scattering particles with different diffusion coefficients and movement speed conditions, which are prepared when preparing a learning model in the measurement device of this embodiment. [Figure 4] FIG. 4 is a diagram for explaining an example of a hardware configuration when attempting to measure non-Newtonian characteristics in the measurement device according to this embodiment. [Figure 5] FIG. 5 is an explanatory diagram showing an optical coherence tomographic image of a fluid to be measured by the measurement device according to this embodiment, and the state in which the diffusion coefficient, moving speed, and moving direction of scattering particles at each position are estimated. [Figure 6] FIG. 6 is an image diagram showing the results of calculating the shear viscosity characteristics of the fluid to be measured in the measurement device according to this embodiment. [Figure 7] FIG. 7 is an image diagram showing the results of calculating the time-dependent change characteristics of the viscosity of the fluid to be measured in the measurement device according to this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of a measuring device and a measuring method will be described in detail with reference to the accompanying drawings.

[0012] 1 is a flowchart showing an example of a flow for determining the non-Newtonian characteristics of a fluid to be measured using the measurement method of the measurement device according to this embodiment. The measurement method of this embodiment is roughly divided into three parts, including a part for preparing a learning model (step S101), a part for measuring the object to be measured (step S102), and a part for analyzing the characteristics of the object to be measured (step S103).

[0013] FIG. 2-1 is a diagram illustrating an example of a hardware configuration used in the part for preparing a learning model in the measurement method of the measurement device according to this embodiment. The measurement device according to this embodiment is a device that acquires optical coherence cross-sectional images by so-called optical coherence tomography. In this embodiment, the measurement device 200 includes a measurement unit 100, a storage unit 23, a display unit 24, and an automatic XYZ stage 16. The measurement unit 100 includes a broadband light source 1, an irradiation optical unit 11, a control unit 12, a spectrophotometer 21, a processing unit 22, and a coupling optical unit 120.

[0014] In the measurement device 200 according to this embodiment, light output from a broadband light source 1 propagates through an optical fiber 2 and then propagates to a coupling optical unit 120, where it is split into two directions by an optical fiber coupler 6 of the coupling optical unit 120. Here, the broadband light source 1 is an example of a light source that emits light (an example of irradiated light). Also, here, the optical fiber coupler 6 is an example of an irradiating optical unit that irradiates at least a portion of the light (an example of irradiated light) emitted from the broadband light source 1 onto a measurement object (an example of an observation object), which is a fluid (e.g., ink) containing particles that reflect or scatter at least the irradiated light. One of the light beams split by the optical fiber coupler 6 is output as parallel light into space via an optical fiber 3 by an optical fiber collimator 7, and is returned to the original optical path by a lens 9 and a mirror 10, where it propagates again through the optical fiber 3.

[0015] The other light split by the optical fiber coupler 6 is introduced into the irradiation optical unit (XY scanner) 11 through the optical fiber 5. In the irradiation optical unit (XY scanner) 11, the light that has been collimated by the optical fiber collimator 8 is irradiated onto the measurement object through scanner mirrors 13 and 14 and a lens 15. A portion of the light (an example of reference light) irradiated onto the surface or inside of the measurement object is reflected or scattered, and propagates through the optical fiber 5 via the same optical path.

[0016] The two return beams returning to the original optical path through the optical fibers 3 and 5 are combined by the optical fiber coupler 6 and guided to the spectrophotometer 21 through the optical fiber 4. That is, the optical fiber coupler 6 is an example of a combining optical unit that combines light reflected or scattered by the measurement object with reference light, which is at least a portion of the illumination light emitted from the broadband light source 1 and is not reflected or scattered by the measurement object. If the optical path length from when the light is split into two directions by the optical fiber coupler 6 to when it reaches the mirror 10 is approximately the same as the optical path length to when the return beam from the measurement object is generated, interference fringes will appear in the spectrum of the combined beam observed by the spectrophotometer 21. The spectrophotometer 21 is an example of a detection unit that detects the combined beam combined by the optical fiber coupler 6.

[0017] In other words, if the optical path length difference of the returning light is small, interference fringes with wide fringe spacing are observed, and as the optical path length difference is increased, interference fringes with narrow fringe spacing are observed. If the optical path length difference is further increased, interference fringes are no longer observed. When returning light is generated from multiple positions on the measurement object, that is, when combined light with multiple optical path length differences overlaps, multiple interference fringes will be superimposed on the spectrum of the combined light.

[0018] The processing unit 22 performs Fourier transform processing or the like on the spectrum containing the interference fringes to analyze from which position on the object to measure the component of the returning light was large, and obtains the intensity distribution of the reflected light and scattered light.

[0019] The control unit 12 controls the illumination optical unit (XY scanner) 11 to illuminate each position on the measurement object with light and obtain the reflected and scattered light intensity distributions along the illumination light axis for each position. In this way, the reflected and scattered light intensity distributions within the two-dimensional or three-dimensional measurement object are obtained, and by repeating this process, the changes in the reflected and scattered light intensity distributions over time are obtained. The reflected and scattered light intensity distributions and their changes over time are called optical coherence tomographic images or optical coherence tomographic dynamic images. Specifically, the control unit 12 is an example of a control unit that acquires optical coherence tomographic images based on the combined light detected by the spectrophotometer 21. The control unit 12 also records the acquired optical coherence tomographic images of the measurement object in the memory unit 23, calculates characteristic values ​​representing the degree of thermal motion and advection motion of particles contained in the measurement object based on the optical coherence tomographic images of the measurement object, and outputs position information of each characteristic value in at least two-dimensional space and time information representing the changes in the characteristic value over time to the display unit 24. Here, the characteristic value representing the degree of thermal motion of particles contained in the object to be measured may be the diffusion coefficient of the particles, and the characteristic value representing the degree of advection motion of the particles may be the advection velocity and advection direction of the particles.

[0020] The measurement object is mounted on an automated XYZ stage 16 controlled by the control unit 12. The automated XYZ stage 16 includes an automated X stage 18, an automated Y stage 19, and an automated Z stage 20. The automated XYZ stage 16 may also include an automated rotation stage or an automated gonio stage. A sealed container 17, through which the output light of the broadband light source 1 passes, is filled with a suspension (described below). The sealed container 17 has two corresponding plate-like members that at least partially transmit the irradiated light. The measurement object is held between the two plate-like members. The automated XYZ stage 16 is an example of a moving means that moves at least one of the two plate-like members of the sealed container 17 while maintaining a constant distance between them. In this case, the control unit 12 records an optical coherence tomographic image while applying a shear force to the measurement object using the automated XYZ stage 16.

[0021] Suspensions contain scattering particles (an example of particles), and when these particles are used as measurement targets, optical coherence tomography (OCT) images reflect a scattered light intensity distribution indicating scattered light from all locations in the suspension. However, the position of each scattering particle cannot be distinguished from the OCT image. The scattered light interferes with itself within the coherence length of the measurement light, and the OCT image is formed by this overlap. Even for suspensions with uniform particle concentration, the scattered light intensity in the corresponding OCT image is not uniform, resulting in a flickering distribution. This is called a speckle pattern. The speckle pattern in the OCT dynamic image varies depending on the motion (violence) of the scattering particles contained in the suspension. In other words, each pixel constituting an OCT image contains information about the interference state resulting from the superposition of irradiated light reflected or scattered from multiple particles present at the corresponding pixel. Furthermore, the OCT image includes a so-called speckle pattern.

[0022] The control unit 12 may also calculate the diffusion coefficient, advection velocity, and advection direction of the scattering particles for each region of the measurement object corresponding to a region indicated by at least one pixel of the optical coherence tomographic image, and determine the spatial distribution of the diffusion coefficient, advection velocity, and advection direction of the scattering particles. Furthermore, the control unit 12 may determine the spatial distribution of the diffusion coefficient, advection velocity, and advection direction of the scattering particles of the measurement object, and the time change of the spatial distribution.

[0023] The control unit 12 may also use machine learning as a method for decomposing the characteristic values ​​representing the motion state of scattering particles contained in the measurement object into the diffusion coefficient of the scattering particles, the advection velocity of the scattering particles, and the advection direction of the scattering particles. In machine learning, speckles included in optical coherence tomographic images obtained by applying different advection velocities and advection directions to a measurement object containing scattering particles with at least different diffusion coefficients may be used as training data. In machine learning, speckles included in optical coherence tomographic images obtained by filling a measurement object containing scattering particles with at least different diffusion coefficients into a sealed container 17, which is an example of a container at least partially having a window that transmits irradiated light, and transporting the sealed container 17 at different speeds and directions may be used as training data.

[0024] The control unit 12 may also calculate the spatial distribution or temporal change of the shear viscosity of a measurement object applied to a substrate in a layer or three-dimensional form. The control unit 12 functions as an example of an environmental measurement means that measures the temperature of the substrate on which the measurement object is applied, the temperature of the gas surrounding the substrate, the humidity of the gas surrounding the substrate, the amount of volatile components in the measurement object contained per unit volume of the gas, and the air pressure of the gas over time. The control unit 12 also calculates the temporal change of the viscosity distribution of the measurement object applied to the substrate due to evaporation based on fluid evaporation viscosity characteristic information recording the relationship between the evaporation rate of the measurement object and the medium viscosity of the measurement object and the measurement results of the environmental measurement means, and calculates the proportion of contributions due to evaporation or condensation of the measurement object and non-Newtonian properties of the measurement object to the spatial distribution or temporal change of the shear viscosity of the measurement object.

[0025] 2-2 is a block diagram showing an example of the hardware configuration of a processing unit included in the measurement device according to this embodiment. The processing unit 22 includes a CPU (Central Processing Unit) 141, a RAM (Random Access Memory) 142, a ROM (Read Only Memory) 143, a light source driver 144, a scanning optical unit driver 145, a detection unit I / F (Interface) 146, and a display unit I / F 147. These components are electrically connected to one another via a system bus 148.

[0026] The CPU 141 comprehensively controls the operation of the measurement unit 100. The CPU 141 uses the RAM 142 as a work area (working region) and executes programs stored in the ROM 143 to control the operation of the measurement unit 100 and realize various functions described below.

[0027] The light source driver 144 is an electric circuit electrically connected to the broadband light source 1 and outputs a drive voltage to the broadband light source 1. The scanning optical unit driver 145 is an electric circuit electrically connected to the scanner mirror 14 and outputs a drive voltage to the scanner mirror 14.

[0028] The detection unit I / F 146 is electrically connected to the spectrophotometer 21, and is an interface that outputs a drive voltage to the spectrophotometer 21 and inputs a detection signal from the spectrophotometer 21.

[0029] The display unit I / F 147 is an interface that is electrically connected to the display unit 24 and outputs the optical coherence tomographic image and / or the characteristic value acquired by the processing unit 22 to the display unit 24.

[0030] Fig. 3 is a diagram showing an example of a combination of suspensions containing scattering particles with multiple different diffusion coefficients and movement speed conditions, which are prepared when preparing a learning model in the measurement device according to this embodiment. It is desirable that the diffusion coefficient of the scattering particles contained in the suspension (fluid to be measured) varies depending on the viscosity of the solvent. Fig. 3 shows that learning data is prepared using a combination of five levels of suspensions with different diffusion coefficients of the scattering particles and six levels of movement speed of the scattering particles.

[0031] Each suspension is filled into a sealed container 17, placed on an automatic XYZ stage 16, and transported at a specified uniform speed. The control unit 12 acquires optical coherence tomography (OCT) moving images under all combinations of conditions while the suspension is being transported at the uniform speed, and stores combinations of OCT moving images for the conditions of the diffusion coefficient, movement speed, and movement direction of the scattering particles. Here, a method for acquiring OCT moving images by moving the sealed container 17 at a uniform speed has been described. However, it is also possible to sandwich the suspension between two flat plates and acquire OCT images when one of the plates is moved at a uniform speed, or to flow the suspension through a pipe and acquire OCT images at a uniform supply speed.

[0032] The control unit 12 constructs a machine learning model using the stored data set of optical coherence tomographic images. Since the speckle pattern of the optical coherence tomographic moving image has information on the diffusion coefficient, movement speed, and movement direction of the scattering particles superimposed thereon, it is possible to associate the diffusion coefficient, movement speed, and movement direction of the scattering particles with the speckle pattern. This association may be performed for each region by spatially dividing the optical coherence tomographic image. A learning model is stored that, when the time change in a certain range of a speckle pattern of a certain size (optical coherence tomographic moving image) is input, outputs the corresponding diffusion coefficient, movement speed, and movement direction of the scattering particles.

[0033] 4 is a diagram illustrating an example of a hardware configuration when measuring non-Newtonian characteristics in the measurement device according to this embodiment. In this embodiment, measurement device 200 is provided with liquid flow path 25 as a measurement target of optical coherence tomography, supply path 26 that supplies a measurement target fluid (an example of an observation target) to this, and discharge path 27 that discharges the measurement target fluid. The state of the measurement target fluid may be such that the measurement target fluid is flowing through liquid flow path 25, or the measurement target fluid may be filled in a space sandwiched between two flat plates and the flat plates are moved, or a state in which a film of the measurement target fluid is formed on a substrate.

[0034] Here, the liquid flow path 25 is an example of a flow path made of a material that is at least partially transparent to the irradiated light. For example, the liquid flow path 25 is a tubular flow path with at least two openings. A measurement object (e.g., a liquid containing a volatile component) is supplied from at least one opening of the tubular flow path by the supply path 26, and an interface is formed between the measurement object and an external fluid (e.g., a gas) outside the tubular flow path at another opening. Here, the interface is a gas-liquid interface consisting of a gas phase and a liquid phase. In this case, the control unit 12 acquires an optical coherence tomographic image of the measurement object including the interface. Specifically, the control unit 12 records an optical coherence tomographic image of the process in which the volatile component evaporates or condenses through the gas-liquid interface. The supply path 26 is an example of a supply means for supplying the measurement object to the liquid flow path 25. The measurement object is filled inside the liquid flow path 25. The control unit 12 reproduces the behavior of the measurement target fluid to be measured, acquires optical coherence tomographic moving images (optical coherence tomography images) while supplying the measurement target fluid through the supply path 26, and records the optical coherence tomographic moving images in the memory unit 23. The control unit 12 is an example of a motion speed control means for controlling the motion speed of the measurement target fluid, and may apply a plurality of different shear forces or a plurality of different shear forces that change over time to the measurement target fluid. The control unit 12 may then calculate the viscosity of the measurement target fluid at a plurality of shear rates and the change in viscosity of the measurement target fluid with a change in shear rate.

[0035] FIG. 5 is an explanatory diagram showing an optical coherence tomography (OCT) image of a fluid to be measured in the measurement device according to this embodiment, and the estimation of the diffusion coefficient, movement speed, and movement direction of scattering particles at each position. FIG. 5(a) shows an OCT moving image of the fluid to be measured flowing through the liquid flow path 25, with a speckle pattern displayed at certain locations in the fluid to be measured. The control unit 12 separates the OCT moving image spatially and temporally, and calculates a likely combination of the diffusion coefficient, movement speed, and movement direction of the scattering particles for each speckle image (speckle pattern) at each position and time using a machine learning model prepared in advance. Furthermore, through this processing, the control unit 12 can display the distribution of the diffusion coefficient of the scattering particles (see FIG. 5(b)) and the distribution of the movement speed and movement direction of the scattering particles (see FIG. 5(c)), as well as their time changes, corresponding to the OCT moving image of the fluid to be measured.

[0036] 6 is an image diagram showing the results of calculating the shear viscosity characteristics of the fluid to be measured using the measurement device of this embodiment. Once the distribution of the movement speeds of the scattering particles in the fluid to be measured is determined as shown in FIG. 5(c), the control unit 12 calculates the shear rate (shear rate) at each position on the optical coherence tomographic image based on this distribution. Furthermore, once the distribution of the diffusion coefficients of the fluid to be measured is determined as shown in FIG. 5(b), the control unit 12 calculates the solvent viscosity distribution at each position on the optical coherence tomographic image of the fluid to be measured according to the Einstein-Stokes equation. The solvent viscosity distribution may be converted into a viscosity distribution based on the diffusion coefficients of the scattering particles using a calibration curve separately prepared using the fluid to be measured.

[0037] The control unit 12 extracts data from the optical coherence tomography dynamic images at positions and times when it is possible to determine that the moving speed of the scattering particles is constant and a steady flow is occurring, extracts the corresponding combination of shear rate and viscosity, and plots a scatter diagram with shear rate on the horizontal axis and viscosity on the vertical axis. As a result, the control unit 12 displays part of the shear viscosity characteristics as shown in Figure 6, making it possible to grasp the shear viscosity characteristics, which are one of the characteristics that indicate the non-Newtonian nature of the fluid being measured.

[0038] That is, the control unit 12 determines the spatial distribution of viscosity of the medium of the measurement target fluid based on the dynamic light scattering method from the spatial distribution of the diffusion coefficient of the scattering particles, determines the spatial distribution of shear rate from the spatial distribution of the advection velocity and advection direction of the scattering particles, and calculates the shear viscosity of the measurement target fluid from the spatial distribution of viscosity and the spatial distribution of shear rate. Furthermore, the control unit 12 calculates the time change in shear viscosity of the measurement target fluid from the time change in the spatial distribution of viscosity and the time change in the spatial distribution of shear rate.

[0039] The control unit also functions as an example of a supply rate control means for controlling the supply rate of the fluid to be measured to the liquid flow path 25, and applies a plurality of different supply rates or a plurality of different supply rates that change over time to the fluid to be measured. The control unit 12 also calculates the viscosity of the fluid to be measured at a plurality of shear rates and the change in viscosity of the object to be measured with a change in the shear rate.

[0040] The control unit 12 also functions as an example of an interface detection means that detects the position and shape of the gas-liquid interface over time, and controls the supply of the measurement object through the supply path 26 based on the detection results of the position and shape of the gas-liquid interface so that at least the position of the gas-liquid interface does not change over time. The control unit 12 may also detect the position and shape of the gas-liquid interface using image processing means for optical coherence tomographic images recorded including the gas-liquid interface. The control unit 12 also calculates the change over time in the amount of evaporation or condensation of volatile components passing through the gas-liquid interface based on the control results of the supply of the measurement object through the supply path 26.

[0041] The control unit 12 may also function as an example of an environmental control unit that controls the gas temperature, gas humidity, the amount of volatile components contained per unit volume of the gas, and the gas air pressure, and may acquire optical coherence tomographic images by changing the evaporation rate of the volatile components. The liquid flow path 25 may also include multiple tubular flow paths with different opening shapes or areas, and different cross-sectional areas and distributions of the tubular flow paths. In this case, the control unit 12 determines at least one of the viscosity distribution of the gas-liquid interface of the object to be measured, its change over time, and the convection speed and direction of the liquid, and its change over time, for each combination of the tubular flow path and multiple evaporation rates of the volatile components.

[0042] Furthermore, the control unit 12 calculates the time required for a solid film to form at the gas-liquid interface based on the measurement results of the viscosity distribution at the gas-liquid interface of the measurement object, its change over time, and the convection speed and direction of the measurement object, and displays or records the calculated time as an index of the ease of forming a solid film on the measurement object.

[0043] FIG. 7 is an illustration of the results of calculating the time-dependent change in viscosity of a fluid to be measured using the measurement device according to this embodiment. The control unit 12 extracts data from the optical coherence tomography dynamic image at positions and times at which it is possible to determine that the velocity of the scattering particles is transiently changing, and extracts the corresponding combinations of shear rate and viscosity. Furthermore, the control unit 12 plots a scatter diagram (see FIG. 7 ) with elapsed time on the horizontal axis and viscosity on the vertical axis for each characteristic of the transient change in the velocity of the scattering particles, i.e., the velocity before and after the change and the rate of change in the velocity. As a result, the control unit 12 can display the process of viscosity change corresponding to the change in the velocity of the scattering particles, and can grasp the degree of thixotropy or rheopexy, which are characteristics that represent the non-Newtonian nature of the fluid to be measured, for example, the time constant of the viscosity change.

[0044] In this way, the measuring device 200 according to this embodiment, which combines OCT and DLS, can separately determine the diffusion coefficient of particles contained in the ink and the speed at which the ink is advected, and can determine the shear viscosity characteristics and time-dependent characteristics of non-Newtonian ink through in-situ observation.

[0045] For example, aspects of the present invention are as follows. <1> a light source that emits irradiation light; an illumination optical unit that illuminates at least a portion of the illumination light emitted from the light source onto an observation object that is a fluid containing particles that reflect or scatter at least the illumination light; a combining optical unit that combines light resulting from the illumination light being reflected or scattered by the observation object and reference light that is at least a portion of the illumination light emitted from the light source and is not reflected or scattered by the observation object; a detection unit that detects the combined light combined by the combining optical unit; a control unit that acquires an optical coherence tomographic image of the observation object based on the combined light detected by the detection unit, The control unit records the optical coherence tomographic image of the fluid from the acquired optical coherence tomographic image of the observed object, calculates characteristic values ​​that represent the degree of thermal motion and advection motion of the particles contained in the fluid based on the optical coherence tomographic image of the fluid, and outputs position information of each of the characteristic values ​​in at least two-dimensional space and time information that represents changes in the characteristic values ​​over time. <2> a pixel constituting the optical coherence tomographic image of the fluid includes information on an interference state obtained by superimposing the irradiation light reflected or scattered from a plurality of the particles present at positions corresponding to the pixel; The optical coherence tomographic image includes a so-called speckle pattern. <1> The measuring device according to claim 1. <3> the characteristic value representing the degree of thermal motion of the particles contained in the fluid is a diffusion coefficient of the particles; the characteristic value representing the degree of the advection motion of the particles contained in the fluid is the advection velocity and the advection direction of the particles; <1> or <2> The measuring device according to claim 1. <4> The control unit calculating a diffusion coefficient of the particle, and an advection velocity and an advection direction of the particle for each region of the fluid corresponding to a region indicated by at least one pixel of the optical coherence tomographic image; determining a spatial distribution of the diffusion coefficient of the particles, the advection velocity of the particles, and the advection direction of the particles; <3> The measuring device according to claim 1. <5> the control unit calculates a spatial distribution of the diffusion coefficient of the particles, the advection velocity of the particles, and the advection direction of the particles in the fluid, and a time change in the spatial distribution. <4> The measuring device according to claim 1. <6> The method of decomposing the characteristic value representing the state of motion of the particles contained in the fluid into a diffusion coefficient of the particles, an advection velocity of the particles, and an advection direction of the particles uses machine learning, In the machine learning, speckles included in the optical coherence tomographic image obtained while applying different advection velocities and advection directions to the fluid containing the particles having at least different diffusion coefficients are used as training data. <3> from <5> 10. The measuring device according to claim 9, wherein <7> In the machine learning, the fluid containing the particles having at least a plurality of different diffusion coefficients is filled into a container having at least a partial window that transmits the irradiation light, and the optical coherence tomographic images are acquired while the container is transported at a plurality of different moving speeds and moving directions, and speckles included in the optical coherence tomographic images are used as training data. <6> The measuring device according to claim 1. <8> the control unit determines a spatial distribution of viscosity of the fluid medium based on a dynamic light scattering method from the spatial distribution of the diffusion coefficients of the particles, determines a spatial distribution of shear rate from the spatial distribution of the advection velocities and advection directions of the particles, and calculates a shear viscosity of the fluid from the spatial distribution of viscosity and the spatial distribution of shear rate. <4> from <7> 10. The measuring device according to claim 9, wherein <9> the control unit calculates the change in shear viscosity over time from the change in the spatial distribution of the viscosity of the fluid and the change in the spatial distribution of the shear rate of the fluid. <8> The measuring device according to claim 1. <10> two opposing plate-like members that at least partially transmit the irradiated light; a movement means for moving at least one of the plate-like members while maintaining a constant distance between the two plate-like members; The fluid is held between the two plate-like members, the control unit records the optical coherence tomographic image while applying shear force to the fluid by the movement means. <3> from <9> 10. The measuring device according to claim 9, wherein <11> the control unit has a motion speed control means for controlling the motion speed of the fluid, subjecting the fluid to a plurality of different shear forces or a plurality of different time-varying shear forces; The control unit calculates the viscosity of the fluid at a plurality of shear rates and a change in viscosity of the fluid with a change in the shear rate. <10> The measuring device according to claim 1. <12> a flow path formed of a member that is at least partially transparent to the irradiation light; a supply means for supplying the fluid to the flow path, The fluid is filled in the flow path, the control unit records the optical coherence tomographic image while supplying the fluid by the supply unit. <3> from <9> 10. The measuring device according to claim 9, wherein <13> the control unit has a supply rate control means for controlling a supply rate of the fluid to the flow path, the supply rate control means applies a plurality of different supply rates or a plurality of different time-varying supply rates to the fluid; The control unit calculates the viscosity of the fluid at a plurality of shear rates and a change in viscosity of the fluid with a change in the shear rate. <12> The measuring device according to claim 1. <14> the flow channel is a tubular flow channel having at least two openings; the fluid is supplied from at least one of the openings of the tubular flow path by the supply means, and an interface between the fluid and a fluid outside the tubular flow path is formed at another of the openings; The optical coherence tomographic image is a tomographic image of the fluid including the interface. <13> The measuring device according to claim 1. <15> the fluid is a liquid, the fluid outside the flow path is a gas, the interface is a gas-liquid interface consisting of a gas phase and a liquid phase, The liquid contains a volatile component, The control unit records the optical coherence tomographic image of the process of evaporation or condensation of the volatile component through the gas-liquid interface. <14> The measuring device according to claim 1. <16> an interface detection means for detecting the position and shape of the gas-liquid interface over time; the control unit controls the supply rate control unit based on the detection result of the interface detection unit so that at least the position of the gas-liquid interface does not change over time. <15> The measuring device according to claim 1. <17> the interface detection means detects the position and shape of the gas-liquid interface by image processing means for the optical coherence tomographic image recorded including the gas-liquid interface; <16> The measuring device according to claim 1. <18> The control unit calculates a change over time in the amount of evaporation or condensation of the volatile components passing through the gas-liquid interface based on the control result of the supply rate control means. <16> or <17> The measuring device according to claim 1. <19> an environmental control means for controlling the temperature of the gas, the humidity of the gas, the amount of the volatile components contained per unit volume of the gas, and the air pressure of the gas; the environment control means changes the evaporation rate of the volatile components to acquire the optical coherence tomographic image. <16> from <18> 10. The measuring device according to claim 9, wherein <20> The tubular flow path uses a plurality of tubular flow paths having different shapes or areas of the openings, and different cross-sectional areas and distributions of the cross-sectional areas of the tubular flow paths, the control unit determines, for each combination of the tubular flow path and a plurality of different evaporation rates of the volatile component, at least one of a viscosity distribution of the gas-liquid interface of the liquid, a change therein over time, a convection velocity and direction of the liquid, and a change therein over time. <16> from <19> 10. The measuring device according to claim 9, wherein <21> the control unit calculates the time required for a solid film to be formed at the gas-liquid interface based on the measurement results of the viscosity distribution of the liquid at the gas-liquid interface, its change over time, and the convection velocity and direction of the liquid, and displays or records the time as an index of the ease of forming a solid film of the liquid. <20> The measuring device according to claim 1. <22> The control unit calculates the spatial distribution of the shear viscosity of the fluid applied to the substrate in a layer or three-dimensional form, and the change over time of the shear viscosity of the fluid. <3> from <9> 10. The measuring device according to claim 9, wherein <23> an environment measuring means for measuring, over time, the temperature of the substrate to which the fluid is applied, the temperature of the gas surrounding the substrate, the humidity of the gas surrounding the substrate, the amount of volatile components in the fluid contained per unit volume of the gas, and the atmospheric pressure of the gas; the control unit calculates a change over time in the viscosity distribution of the fluid applied to the substrate due to evaporation based on fluid evaporation viscosity characteristic information that records the relationship between the evaporation rate of the fluid and the medium viscosity of the fluid and the measurement results of the environment measurement means, and calculates the ratio of contributions of evaporation or condensation of the fluid and non-Newtonian properties of the fluid to the spatial distribution of the shear viscosity of the fluid or the change over time. <22> The measuring device according to claim 1. <24> a light source that emits illumination light; an illumination optical unit that irradiates at least a portion of the illumination light emitted from the light source onto an observation object that is a fluid containing particles that reflect or scatter at least the illumination light; a combining optical unit that combines light resulting from the illumination light being reflected or scattered by the observation object and reference light that is at least a portion of the illumination light emitted from the light source and is not reflected or scattered by the observation object; a detection unit that detects the combined light combined by the combining optical unit; and a control unit that acquires an optical coherence tomographic image of the observation object based on the combined light detected by the detection unit, recording the optical coherence tomographic image of the fluid from the acquired optical coherence tomographic image of the observation object; determining characteristic values ​​representing the degrees of thermal motion and advection motion of the particles contained in the fluid based on the optical coherence tomographic image of the fluid; outputting position information of each of the characteristic values ​​in at least two-dimensional space and time information representing changes in the characteristic values ​​over time; Measurement methods including. [Explanation of symbols]

[0046] 1 Broadband light source 2,3,4,5 Optical Fiber 6 Fiber Optic Couplers 7,8 Fiber optic collimator 9,15 Lens 10. Mirror 11 Irradiation optical unit (XY scanner) 12 Control Unit 13,14 Scanner mirror 16 Automatic XYZ Stage 17 Airtight containers 18 Automatic X-stage 19 Automatic Y stage 20 Automatic Z stage 21 Spectrophotometer 22 Processing section 23 Memory section 24 Display section 25 Liquid flow path 26 Supply route 27 Exhaust channel 200 Measuring Equipment [Prior art documents] [Patent documents]

[0047] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-024089

Claims

1. a light source that emits irradiation light; an illumination optical unit that illuminates at least a portion of the illumination light emitted from the light source onto an observation object that is a fluid containing particles that reflect or scatter at least the illumination light; a combining optical unit that combines light resulting from the illumination light being reflected or scattered by the observation object and reference light that is at least a portion of the illumination light emitted from the light source and is not reflected or scattered by the observation object; a detection unit that detects the combined light combined by the combining optical unit; a control unit that acquires an optical coherence tomographic image of the observation object based on the combined light detected by the detection unit, The control unit records the optical coherence tomographic image of the fluid from the acquired optical coherence tomographic image of the observed object, calculates characteristic values ​​that represent the degree of thermal motion and advection motion of the particles contained in the fluid based on the optical coherence tomographic image of the fluid, and outputs position information of each of the characteristic values ​​in at least two-dimensional space and time information that represents changes in the characteristic values ​​over time.

2. a pixel constituting the optical coherence tomographic image of the fluid includes information on an interference state obtained by superimposing the irradiation light reflected or scattered from a plurality of the particles present at positions corresponding to the pixel; The measurement device according to claim 1 , wherein the optical coherence tomographic image includes a speckle pattern.

3. the characteristic value representing the degree of thermal motion of the particles contained in the fluid is a diffusion coefficient of the particles; The measuring device according to claim 1 , wherein the characteristic value representing the degree of the advection movement of the particles contained in the fluid is an advection velocity and an advection direction of the particles.

4. The control unit calculating a diffusion coefficient of the particle, and an advection velocity and an advection direction of the particle for each region of the fluid corresponding to a region indicated by at least one pixel of the optical coherence tomographic image; The measuring device according to claim 3 , wherein the measuring device determines a spatial distribution of the diffusion coefficient of the particles, the advection velocity of the particles, and the advection direction of the particles.

5. 5. The measuring device according to claim 4, wherein the control unit determines a spatial distribution of a diffusion coefficient of the particles, a particle advection velocity, and a particle advection direction in the fluid, and a change in the spatial distribution over time.

6. The method of decomposing the characteristic value representing the state of motion of the particles contained in the fluid into a diffusion coefficient of the particles, an advection velocity of the particles, and an advection direction of the particles uses machine learning, The measuring device of claim 3, wherein the machine learning uses speckles contained in the optical coherence tomographic image as training data when the optical coherence tomographic image is acquired while applying different advection velocities and advection directions to the fluid containing the particles having at least different diffusion coefficients.

7. 7. The measuring device of claim 6, wherein the machine learning involves filling a container having at least a partial window that transmits the irradiation light with the fluid containing the particles having at least a plurality of different diffusion coefficients, and transporting the container at a plurality of different moving speeds and moving directions while acquiring the optical coherence tomographic images, and using speckles contained in the optical coherence tomographic images as training data.

8. 5. The measuring device according to claim 4, wherein the control unit determines a spatial distribution of viscosity of the fluid medium based on a dynamic light scattering method from the spatial distribution of the diffusion coefficients of the particles, determines a spatial distribution of shear rate from the spatial distribution of the advection velocities and advection directions of the particles, and calculates a shear viscosity of the fluid from the spatial distribution of viscosity and the spatial distribution of shear rate.

9. The measuring device according to claim 8 , wherein the control unit calculates the change in shear viscosity over time from the change in the spatial distribution of the viscosity of the fluid and the change in the spatial distribution of the shear rate of the fluid.

10. two opposing plate-like members that at least partially transmit the irradiated light; a movement means for moving at least one of the plate-like members while maintaining a constant distance between the two plate-like members, The fluid is held between the two plate-like members, The measurement device according to claim 3 , wherein the control unit records the optical coherence tomographic image while the movement means applies a shear force to the fluid.

11. the control unit has a motion speed control means for controlling the motion speed of the fluid, subjecting the fluid to a plurality of different shear forces or a plurality of different time-varying shear forces; The measurement device according to claim 10 , wherein the control unit calculates the viscosity of the fluid at a plurality of shear rates and a change in viscosity of the fluid with a plurality of changes in the shear rate.

12. a flow path formed of a member that is at least partially transparent to the irradiation light; a supply means for supplying the fluid to the flow path, The fluid is filled in the flow path, The measurement device according to claim 3 , wherein the control unit records the optical coherence tomographic image while the fluid is being supplied by the supply unit.

13. the control unit has a supply rate control means for controlling a supply rate of the fluid to the flow path, the supply rate control means applies a plurality of different supply rates or a plurality of different time-varying supply rates to the fluid; The measurement device according to claim 12 , wherein the control unit calculates the viscosity of the fluid at a plurality of shear rates and a change in viscosity of the fluid with a plurality of changes in the shear rate.

14. the flow channel is a tubular flow channel having at least two openings; the fluid is supplied from at least one of the openings of the tubular flow path by the supply means, and an interface between the fluid and a fluid outside the tubular flow path is formed at another of the openings; The measurement device according to claim 13 , wherein the optical coherence tomographic image is a tomographic image of the fluid including the interface.

15. the fluid is a liquid, the fluid outside the flow path is a gas, the interface is a gas-liquid interface consisting of a gas phase and a liquid phase, The liquid contains a volatile component, The measurement device according to claim 14 , wherein the control unit records the optical coherence tomographic images of the process of evaporation or condensation of the volatile components through the gas-liquid interface.

16. an interface detection means for detecting the position and shape of the gas-liquid interface over time; The measuring device according to claim 15, wherein the control unit controls the supply rate control unit based on the detection result of the interface detection unit so that at least the position of the gas-liquid interface does not change over time.

17. The measurement device according to claim 16 , wherein the interface detection means detects the position and shape of the gas-liquid interface by using image processing means for the recorded optical coherence tomographic image including the gas-liquid interface.

18. The measuring device according to claim 16 , wherein the control unit calculates a change over time in the amount of evaporation or condensation of the volatile component that has passed through the gas-liquid interface based on a control result of the supply rate control means.

19. an environmental control means for controlling the temperature of the gas, the humidity of the gas, the amount of the volatile components contained per unit volume of the gas, and the air pressure of the gas; The measurement device according to claim 16 , wherein the environmental control means acquires the optical coherence tomographic image by changing an evaporation rate at which the volatile components evaporate.

20. The tubular flow path uses a plurality of tubular flow paths having different shapes or areas of the openings, and different cross-sectional areas and distributions of the cross-sectional areas of the tubular flow paths, 17. The measuring device according to claim 16, wherein the control unit determines, for each combination of the tubular flow path and a plurality of different evaporation rates of the volatile component, at least one of a viscosity distribution of the gas-liquid interface of the liquid, a change therein over time, a convection speed and direction of the liquid, and a change therein over time.

21. 21. The measuring device according to claim 20, wherein the control unit calculates a time required for a solid film to be formed at the gas-liquid interface based on measurement results of a viscosity distribution at the gas-liquid interface of the liquid, a change therein over time, and a convection velocity and direction of the liquid, and displays or records the time as an index of ease of forming a solid film of the liquid.

22. The measuring device according to claim 3 , wherein the control unit calculates a spatial distribution of shear viscosity of the fluid and its change over time for the fluid applied to the substrate in a layer or three-dimensional form.

23. an environment measuring means for measuring, over time, the temperature of the substrate to which the fluid is applied, the temperature of the gas surrounding the substrate, the humidity of the gas surrounding the substrate, the amount of volatile components in the fluid contained per unit volume of the gas, and the atmospheric pressure of the gas; 23. The measurement device according to claim 22, wherein the control unit calculates a change in viscosity distribution of the fluid applied to the substrate due to evaporation based on fluid evaporation viscosity characteristic information that records the relationship between the evaporation rate of the fluid and the medium viscosity of the fluid and the measurement results of the environmental measurement means, and calculates the proportion of contributions due to evaporation or condensation of the fluid and non-Newtonian properties of the fluid to the spatial distribution of the shear viscosity of the fluid or its change over time.

24. a light source that emits illumination light; an illumination optical unit that irradiates at least a portion of the illumination light emitted from the light source onto an observation object that is a fluid containing particles that reflect or scatter at least the illumination light; a combining optical unit that combines light resulting from the illumination light being reflected or scattered by the observation object and reference light that is at least a portion of the illumination light emitted from the light source and is not reflected or scattered by the observation object; a detection unit that detects the combined light combined by the combining optical unit; and a control unit that acquires an optical coherence tomographic image of the observation object based on the combined light detected by the detection unit, recording the optical coherence tomographic image of the fluid from the acquired optical coherence tomographic image of the observation object; determining characteristic values ​​representing the degrees of thermal motion and advection motion of the particles contained in the fluid based on the optical coherence tomographic image of the fluid; outputting position information of each of the characteristic values ​​in at least two-dimensional space and time information representing changes in the characteristic values ​​over time; Measurement methods including.

Images