Light measurement method and light measurement device

Abstract

Provided are a light measurement method and a light measurement device with which the particle size and particle size distribution of particles included in a dispersion liquid containing particles having a light-absorbing property are measured with high accuracy. This light measurement method for a particle-containing dispersion liquid comprises: a measurement step for measuring scattered light, which is obtained by changing the intensity of incident light and then causing the incident light to enter the dispersion liquid, a plurality of times; a conversion step for converting a signal of the scattered light measured multiple times in the measurement step into a plurality of pieces of time variation characteristic data of the scattered electric field or the scattered intensity; and a particle diameter calculation step for calculating the particle diameter of the particles using the plurality of pieces of time variation characteristic data of the scattering electric fields or scattering intensities obtained in the conversion step.

Description

Technical Field

[0001] This invention relates to a method and apparatus for measuring the optical properties of a dispersion containing particles, and more particularly to a method and apparatus for measuring the particle size or particle size distribution of particles that have the property of absorbing light. Background Technology

[0002] In various fields such as industry, environment, medicine and academia, it is important and necessary to quantify the precise size of nanoparticles in liquids ranging from 1 to 100 nm.

[0003] Representative methods for quantifying nanoparticles include dynamic light scattering, low-coherence dynamic light scattering, particle tracking analyzers that measure particle displacement under a microscope, and multimodal light scattering measurements that combine Mie scattering angle distribution and dynamic light scattering information. These methods are used to determine the particle diffusion coefficient, which is then converted to particle size. Currently, more specific methods for particle measurement have been proposed.

[0004] For example, Patent Document 1 describes a measuring device for measuring the dynamic light scattering of particles in a sample medium. The measuring device includes: a light splitting unit for splitting light from a low-coherence light source; an irradiation unit for irradiating the sample medium with one of the light split by the light splitting unit; a phase modulation unit for phase modulation of the other light split by the light splitting unit; a spectroscopic acquisition unit for decomposing the phase-modulated light and the scattered light from the sample medium into wavelengths and acquiring the spectroscopic spectrum of the interference light of the phase-modulated light and the scattered light; and a measuring unit for measuring the dynamic light scattering of particles based on the acquired spectroscopic spectrum. The measuring unit calculates the intensity signal at each position of the scattering point in the sample medium based on the acquired spectroscopic spectrum, calculates the power spectrum at each position of the scattering point based on the time change of the intensity signal at each position of the scattering point, and calculates the diffusion coefficient of the particles at each position of the scattering point based on the calculated power spectrum.

[0005] Patent document 1 describes the following: by using the Stokes-Einstein formula to determine the particle size based on the diffusion coefficient, it is also possible to simultaneously measure the particle size distribution in the sample medium (the particle size at each location of the scattering point).

[0006] Previous technical documents

[0007] Patent documents

[0008] Patent Document 1: International Publication No. 2013 / 077137 Summary of the Invention

[0009] The technical problem to be solved by the invention

[0010] Patent Document 1 describes the use of the Stokes-Einstein formula (refer to equation (1) below) to determine the particle size and particle size distribution based on the diffusion coefficient. However, Patent Document 1 does not consider the case where particles absorb light from low-coherence light sources. When particles absorb light, their temperature may sometimes rise. Here, the Stokes-Einstein formula above contains a temperature term, and when the temperature of the particles rises or changes, it is impossible to obtain an accurate particle size.

[0011] Therefore, in Patent Document 1, it is impossible to accurately determine the particle size and particle size distribution of black particles such as carbon black and pigment particles that have the property of absorbing light.

[0012] To avoid the effects of light absorption by particles, a light source with wavelengths that particles do not absorb could be used; however, preparing such a light source would be costly. Furthermore, black particles and similar materials absorb light over a wide wavelength range, making it difficult to eliminate the effects of light absorption.

[0013] Therefore, under the current circumstances, it is difficult to accurately quantify the particle size and particle size distribution of particles with light-absorbing properties.

[0014] The purpose of this invention is to provide a method and apparatus for high-precision determination of the particle size and particle size distribution of particles contained in a dispersion containing particles with light-absorbing properties.

[0015] means for solving technical problems

[0016] To achieve the above objective, the invention [1] is a photometric method for a dispersion containing particles. The photometric method includes: a measurement step, which measures the scattered light obtained by repeatedly measuring the incident light after changing its intensity and then incident on the dispersion; a conversion step, which converts the scattered light signal obtained by multiple measurements in the measurement step into multiple time-varying characteristic data of scattered electric fields or scattered intensities; and a particle size calculation step, which uses the time-varying characteristic data of multiple scattered electric fields or scattered intensities obtained through the conversion step to calculate the particle size.

[0017] Invention [2] is the light measurement method described in Invention [1], wherein in the particle size calculation process, it is assumed that the diffusion coefficient of the particle is linearly dependent on the intensity of incident light. The time variation characteristics of multiple scattering electric fields or scattering intensities are analyzed to determine the particle size or the relationship between the particle diffusion coefficient and the intensity of incident light, thereby determining the particle size.

[0018] Invention [3] is the photometry method described in Invention [2], which further comprises: a step of obtaining a second temperature after the temperature of a particle at a first temperature rises due to light absorption by incident light; and a step of calculating the particle size at the second temperature using a formula representing the diffusion coefficient when the temperature rise occurs, based on the particle size calculated in the particle size calculation step.

[0019] Invention [4] is a photometric method for a dispersion containing particles. The photometric method includes: a measurement step, which measures the scattered light obtained by changing the intensity of the incident light and then incident on the dispersion; a conversion step, which obtains time variation characteristic data of multiple scattered electric fields or scattering intensities based on the multiple scattered light obtained through the measurement step; and a particle size distribution calculation step, which calculates the particle size distribution using the time variation characteristic data of multiple scattered electric fields or scattering intensities obtained through the conversion step.

[0020] Invention [5] is the photometric method described in Invention [4], wherein the particle size distribution calculation step further comprises: a step of using time variation characteristic data of multiple scattering electric fields or scattering intensities to determine an index value representing the temperature dependence of particle size; and a step of using the index value representing the temperature dependence of particle size to correct the particle size distribution of the particles determined in the particle size distribution calculation step.

[0021] The invention [6] is the light measurement method described in the invention [4], which further includes: a step of obtaining a second temperature after the temperature of the particles rises due to light absorption by the incident light at the first temperature; and in the particle size distribution calculation step, the particle size distribution is calculated by using the second temperature in the diffusion coefficient obtained from the time variation characteristics data of multiple scattering electric fields or scattering intensities.

[0022] Invention [7] is the light measurement method described in any of the inventions [1] to [6], wherein the scattered light is the scattered light obtained by changing the value of at least one of the measurement parameters, the scattering angle and the measurement wavelength.

[0023] Invention [8] is the light measurement method described in any of the inventions [1] to [7], wherein the measurement step is a step of repeatedly measuring the scattering intensity of the scattered light obtained by changing the intensity of the incident light and then incident on the dispersion liquid, thereby obtaining multiple scattering intensity data, and the conversion step is a step of obtaining multiple scattering electric field or scattering intensity time variation characteristic data from the multiple scattering intensity data obtained through the measurement step.

[0024] Invention [9] is the optical measurement method described in Invention [7], wherein the dispersion contains multiple types of particles, and the optical measurement method has: a conversion step, which converts the signals of multiple scattered light obtained through the measurement step into multiple time-averaged scattered electric field data or time-averaged scattered intensity data; and a calculation step, which calculates the particle size or particle size distribution of each of the multiple particle types based on the time-averaged scattered electric field data or time-averaged scattered intensity data and time variation characteristic data.

[0025] Invention

[10] is the light measurement method described in Invention [9], wherein the measurement process is as follows: a process of repeatedly measuring the scattering intensity of the scattered light obtained by changing the intensity of the incident light and then incident on the dispersion liquid, thereby obtaining multiple scattering intensity data; and a process of repeatedly measuring the scattering intensity of the scattered light obtained by changing the value of at least one of the measurement parameters, the scattering angle and the measurement wavelength, thereby obtaining multiple scattering intensity data; and a conversion process of calculating multiple scattering electric fields or time variation characteristic data of scattering intensity based on the multiple scattering intensity data obtained through the measurement process.

[0026] Invention

[11] is the optical measurement method described in any of the inventions [1] to

[10] , wherein the time variation characteristics of the scattered electric field or the scattered intensity are autocorrelation function or power spectrum.

[0027]

[12] The invention is a photometric device, which is a photometric device for a dispersion containing particles. The photometric device has: a light source that causes incident light to change intensity and then be incident on the dispersion; a measuring unit that measures the scattered light obtained by causing the incident light to change intensity and then be incident on the dispersion multiple times; a conversion unit that obtains multiple time variation characteristic data of scattered electric fields or scattered intensity based on the multiple scattered light obtained by the measuring unit; and a particle size calculation unit that calculates the particle size using the multiple time variation characteristic data of scattered electric fields or scattered intensity obtained by the conversion unit.

[0028] Invention

[13] is the light measuring device described in invention

[12] , wherein the particle size calculation unit assumes that the diffusion coefficient of the particle is linearly dependent on the intensity of incident light, analyzes the time variation characteristics data of multiple scattering electric fields or scattering intensities, and calculates the particle size or the relationship between the particle diffusion coefficient and the intensity of incident light, thereby calculating the particle size.

[0029] Invention

[14] is the light measuring device described in invention

[12] or

[13] , wherein the particle size calculation unit obtains a second temperature after the temperature of the particles at the first temperature rises due to light absorption by the incident light, and calculates the particle size of the particles at the second temperature using an expression representing the diffusion coefficient when the temperature rise occurs, based on the particle size of the particles calculated by the particle size calculation unit.

[0030] Invention

[15] is a photometric device for a dispersion containing particles. The photometric device includes: a light source that causes incident light to change intensity and then be incident on the dispersion; a measuring unit that measures the scattered light obtained by causing the incident light to change intensity and then be incident on the dispersion multiple times; a conversion unit that obtains multiple time-varying characteristic data of scattered electric fields or scattered intensities based on the multiple scattered light obtained by the measuring unit; and a particle size distribution calculation unit that calculates the particle size distribution using the multiple time-varying characteristic data of scattered electric fields or scattered intensities obtained by the conversion unit.

[0031] Invention

[16] is the light measurement device described in invention

[15] , wherein the particle size distribution calculation unit uses time variation characteristic data of multiple scattering electric fields or scattering intensities obtained by the conversion unit to calculate an index value representing the temperature dependence of particle size, and uses the index value representing the temperature dependence of particle size to correct the particle size distribution.

[0032] Invention

[17] is the light measurement device described in invention

[15] , wherein the particle size distribution calculation unit obtains a second temperature after the temperature of the particles rises due to light absorption by the incident light at a first temperature, and uses the second temperature in the diffusion coefficient obtained from the time variation characteristics data of multiple scattering electric fields or scattering intensities to calculate the particle size distribution.

[0033] Invention

[18] is the light measuring device described in any of the inventions

[12] to

[17] , wherein the scattered light is the scattered light obtained by changing the value of at least one of the measuring parameters, the scattering angle and the measuring wavelength.

[0034] Invention

[19] is the light measuring device described in any of the inventions

[12] to

[118] , which has: a measuring unit for measuring the intensity of the incident light.

[0035] Invention

[20] is the light measurement device described in any of the inventions

[12] to

[19] , which has a low coherence interferometer.

[0036] Invention

[21] is the light measuring device described in any of the inventions

[12] to

[20] , wherein the measuring unit measures the scattering intensity of the scattered light obtained by changing the intensity of the incident light and then incident on the dispersion liquid, thereby obtaining multiple scattering intensity data, and the conversion unit obtains multiple scattering electric field or scattering intensity time variation characteristic data from the multiple scattering intensity data obtained by the measuring unit.

[0037] Invention

[22] is the light measuring device described in any one of the inventions

[12] to

[24] , wherein the dispersion contains multiple types of particles, the conversion unit converts the signals of multiple scattered light obtained by the measuring unit into multiple time-averaged scattered electric field data or time-averaged scattered intensity data, and the particle size calculation unit calculates the particle size of each of the multiple particle types based on the time-averaged scattered electric field data or time-averaged scattered intensity data and time variation characteristic data.

[0038] Invention

[23] is the light measuring device described in any of the inventions

[12] to

[24] , wherein the dispersion contains multiple types of particles, the conversion unit converts the signals of multiple scattered light obtained by the measuring unit into multiple time-averaged scattered electric field data or time-averaged scattered intensity data, and the particle size distribution calculation unit calculates the particle size distribution of each of the multiple particle types based on the time-averaged scattered electric field data or time-averaged scattered intensity data and time variation characteristic data.

[0039] Invention

[24] is the light measuring apparatus described in invention

[22] or

[23] , wherein the measuring unit repeatedly measures the scattering intensity of the scattered light obtained by changing the intensity of the incident light and then incident it into the dispersion liquid, thereby obtaining multiple scattering intensity data, and repeatedly measures the scattering intensity of the scattered light obtained by changing the value of at least one of the measuring parameters, the scattering angle and the measuring wavelength, thereby obtaining multiple scattering intensity data, and the conversion unit is a process of calculating multiple scattering electric fields or time variation characteristic data of scattering intensity based on the multiple scattering intensity data obtained by the measuring unit.

[0040] Invention

[25] is the light measuring device described in any of the inventions

[12] to

[24] , wherein the time variation characteristic data of the scattered electric field or the scattered intensity is an autocorrelation function or a power spectrum.

[0041] Invention Effects

[0042] According to the present invention, a method and apparatus for measuring the particle size and particle size distribution of particles contained in a dispersion containing particles with light-absorbing properties can be provided with high precision. Attached Figure Description

[0043] Figure 1 It is a graph representing the dependence of the autocorrelation function on the incident light intensity.

[0044] Figure 2 It is a graph showing the relationship between the diffusion coefficient of a particle and the intensity of incident light.

[0045] Figure 3 It is a graph showing the relationship between the reciprocal of the particle size of various particles and the intensity of incident light.

[0046] Figure 4It is a graph showing the relationship between the diffusion coefficient of a particle and the intensity of the incident light for each wavelength of the incident light.

[0047] Figure 5 This is a graph showing an example of the power spectrum of a particle for each incident light intensity.

[0048] Figure 6 It is a graph showing the relationship between the reciprocal of the particle size and the intensity of the incident light.

[0049] Figure 7 This is a schematic diagram illustrating a first example of a light measuring apparatus according to an embodiment of the present invention.

[0050] Figure 8 This is a schematic diagram illustrating a second example of a light measuring apparatus according to an embodiment of the present invention.

[0051] Figure 9 This is a schematic diagram illustrating a third example of a light measuring apparatus according to an embodiment of the present invention.

[0052] Figure 10 This is a flowchart illustrating the fourth example of the light measurement method according to an embodiment of the present invention.

[0053] Figure 11 This is the histogram of particle A.

[0054] Figure 12 This is the histogram of particle B.

[0055] Figure 13 This is a flowchart illustrating the fifth example of the light measurement method according to an embodiment of the present invention.

[0056] Figure 14 It is a graph representing the calculated values ​​of the scattering angle and scattering intensity for each refractive index of particles of the same size.

[0057] Figure 15 This is a graph illustrating an example of the relationship between scattering intensity and the measurement wavelength.

[0058] Figure 16 This is another example of a graph showing the relationship between scattering intensity and the measurement wavelength.

[0059] Figure 17 This is a flowchart illustrating the sixth example of the light measurement method according to an embodiment of the present invention. Detailed Implementation

[0060] Hereinafter, the optical measurement method and optical measurement apparatus of the present invention will be described in detail with reference to the preferred embodiments shown in the accompanying drawings.

[0061] Furthermore, the figures described below are illustrative for illustrating the present invention, and the present invention is not limited to the figures shown below.

[0062] Additionally, the "~" sign indicating a numerical range includes the values ​​listed on either side. For example, ε represents the numerical value ε. α ~ numerical value ε β This refers to the range of ε, which includes the value ε. α sum of values ​​ε β The range of , if expressed in mathematical symbols, is . .

[0063] Unless otherwise specified, terms such as "angle expressed in specific numerical values" and "parallel" include the generally permissible error range in the corresponding technical field.

[0064] Furthermore, regarding temperature, unless otherwise specified, it includes the range of error generally permissible in the relevant technical field.

[0065] (Principle of optical measurement)

[0066] First, the principle of particle size measurement will be explained.

[0067] There are known methods for measuring the diffusion coefficient of particles and converting it into particle size.

[0068] According to the Stokes-Einstein formula shown in equation (1), the particle size d0 is quantified based on the particle diffusion coefficient D. In equation (1), k B Let η be the Boltzmann constant, T0 be the temperature of the solvent, and η0 be the viscosity of the solvent. In the following equation (1), the absorption of light by the particles is not considered. Furthermore, the solvent is the solvent in the dispersion containing the particles.

[0069] Here, particle absorption of light means that light incident on a particle is drawn into the particle's interior. Sometimes, the particle's temperature rises due to light absorption. Therefore, particles with the property of absorbing light sometimes experience a temperature increase through light absorption. Furthermore, light absorption is used in the same sense as the aforementioned absorption of light.

[0070] [Formula 1]

[0071]

[0072] Here, taking into account the light absorption of particles, such as Figure 1 As shown, in dynamic light scattering measurements, the autocorrelation function of particles with light-absorbing properties changes according to the incident light intensity for each incident light intensity.

[0073] Figure 1This represents the dependence of the autocorrelation function of a yellow pigment in an aqueous dispersion on the intensity of incident light. Specifically, it represents the dependence of the autocorrelation function of the particles on the intensity of incident light. Figure 1 Two yellow pigments with different particle sizes were used, one of which was PY74 (CI Pigment Yellow 74). Water was used as the solvent for the aqueous dispersion of the aforementioned yellow pigment. The measurement wavelength was 488 nm.

[0074] Additionally, ND as shown below indicates the amount of incident light transmitted through the filter; ND50 has a transmitted light amount of 50%, and ND100 has a transmitted light amount of 100%.

[0075] Figure 1 The symbol 10a represents the autocorrelation function measured for an aqueous dispersion of yellow pigment under conditions of incident light intensity of 20 mW and ND50. That is, the actual intensity of the incident light on the yellow pigment dispersed in the liquid is 10 mW.

[0076] The symbol 10b represents the autocorrelation function measured for an aqueous dispersion of yellow pigment under conditions of incident light intensity of 40 mW and ND50. That is, the actual intensity of the incident light on the yellow pigment dispersed in the liquid is 20 mW.

[0077] The symbol 10c represents the autocorrelation function measured for an aqueous dispersion of yellow pigment under conditions of incident light intensity of 60 mW and ND50. That is, the actual intensity of the incident light on the yellow pigment dispersed in the liquid is 30 mW.

[0078] The symbol 10d represents the autocorrelation function of an aqueous dispersion of yellow pigment measured under conditions of incident light intensity of 80 mW and ND50. That is, the actual intensity of the incident light on the yellow pigment dispersed in the liquid is 40 mW.

[0079] The symbol 10e represents the autocorrelation function measured for an aqueous dispersion of yellow pigment under conditions of incident light intensity of 100 mW and ND50. That is, the actual intensity of the incident light on the yellow pigment dispersed in the liquid is 50 mW.

[0080] The symbol 10f represents the autocorrelation function measured for an aqueous dispersion of yellow pigment under the conditions of incident light intensity of 80 mW and ND100. That is, the actual intensity of the incident light on the yellow pigment dispersed in the liquid is 80 mW.

[0081] The symbol 10g represents the autocorrelation function of an aqueous dispersion of yellow pigment measured under conditions of incident light intensity of 100mW and ND100. That is, the actual intensity of the incident light on the yellow pigment dispersed in the liquid is 100mW.

[0082] The autocorrelation function of the scattering intensity is represented by the following equation (2). In equation (2), q represents the scattering vector. τ represents the time delay of the autocorrelation function.

[0083] The diffusion coefficient D and the scattering vector q have the relationship shown in equation (2).

[0084] (2)

[0085] Furthermore, the scattering vector q is a constant determined by the wavelength of the light source and the scattering angle. Therefore, by... Figure 1 The graphs of the autocorrelation function, denoted by symbols 10a to 10g, fit the exponential function exp(-2Dq). 2 τ), can be used to calculate the diffusion coefficient D, and the particle size d0 can be obtained using equation (1).

[0086] For example, suppose the particle has a particle size, then equation (2) can be expressed as G2(τ)-1=A0·exp(-2Dq) 2 τ). In this case, as described above, by applying the exponential function exp(-2Dq) 2 By fitting τ), the diffusion coefficient D can be obtained, and the particle size d0 can be obtained using equation (1). In addition, the above A0 is the component corresponding to the proportion of the histogram described later.

[0087] Therefore, as described later, it is possible to use time-varying characteristic data of multiple scattering electric fields or scattering intensities, such as autocorrelation functions or power spectra, to determine the particle size.

[0088] Furthermore, it is also possible to fit the exponential function exp(-2Dq) 2 The diffusion coefficient D is obtained by using τ. Therefore, the particle size d can be determined from the obtained diffusion coefficient D according to equation (1). As mentioned above, different particle sizes can be obtained for each incident light intensity.

[0089] In addition, the above exponential function exp(-2Dq) 2 The fitting method for τ is not particularly limited and can make appropriate use of known methods.

[0090] Here, the relationship between the particle diffusion coefficient obtained by analyzing the autocorrelation function and the incident light intensity is studied, and the results are as follows: Figure 2The diffusion coefficient of a particle exhibits a linear dependence, for example, represented by line 12. That is, the diffusion coefficient of the particle is linearly dependent on the intensity of incident light. In this case, the particle size obtained by extrapolating the diffusion coefficient to a value of 0 (zero) from the incident light intensity in line 12 is a particle size independent of the incident light intensity. Thus, by utilizing the linear dependence of the particle's diffusion coefficient on the intensity of incident light, even particles with light-absorbing properties can have a particle size independent of the incident light intensity. Therefore, it is possible to accurately measure the particle size of particles contained in a dispersion containing particles with light-absorbing properties.

[0091] Furthermore, the extrapolation method for extrapolating the incident light intensity to 0 is not limited to linear. As a nonlinear method, extrapolation can also be performed by fitting an arbitrary function.

[0092] Regarding the relationship between the particle diffusion coefficient and the incident light intensity obtained from the analysis of the autocorrelation function, besides Figure 2 This also applies to particles of other colors, in addition to those shown.

[0093] Furthermore, while the diffusion coefficient was used in the above analysis example, the relationship between the reciprocal of the particle size and the incident light intensity remains the same as with the diffusion coefficient, even when the reciprocal of the particle size is used instead. Specifically, for example, as... Figure 3 As shown by lines 13 and 14, the relationship between the reciprocal of the particle size and the incident light intensity holds true. Furthermore, Figure 2 The vertical axis represents the diffusion coefficient. Figure 3 The vertical axis represents the reciprocal of the particle size.

[0094] On the other hand, in the case of particles with small light absorption, such as particles that are transparent to light of the wavelength of the incident light, such as Figure 3 As shown by line 15, the dependence on incident light intensity is extremely small. Therefore, the difference between the particle size obtained by extrapolating the incident light intensity to 0 (zero) and the particle size obtained when the incident light intensity is greater than 0 is extremely small. Therefore, for particles with low light absorption, it is not necessary to extrapolate the incident light intensity to 0 (zero) to obtain the particle size.

[0095] Here, when the complex refractive index of the material constituting the particle is expressed as N≡n+ik, transparency occurs when k=0. That is, a transparent particle is a particle in N≡n+ik where k=0.

[0096] Furthermore, in the formula N≡n+ik representing the complex refractive index, i represents an imaginary number. The real part n of the complex refractive index is called the so-called refractive index. The imaginary part k of the complex refractive index is called the extinction coefficient representing absorption.

[0097] Furthermore, although it depends on the intensity of the irradiated light, it can be treated as an almost transparent particle even if it is not strictly k=0, but around k≈0.

[0098] Line 13 represents the results in a dispersion of red pigment using PR254 (CI Pigment Red 254) as the red pigment.

[0099] Line 14 represents the result in a dispersion of red pigment using PR272 (CI Pigment Red 272) as the red pigment. Lines 13 and 14 were measured at a wavelength of 488 nm.

[0100] Line 15 represents the results for a dispersion using polystyrene particles with a particle size of 100 nm. Polystyrene particles are low light absorbers, and the Nanobead NIST Traceable Particle Size Standard, 100 nm, was used. The solvent for the dispersion was water. The measurement wavelength for line 15 was 488 nm.

[0101] Even when measuring dispersions containing the same particles while changing the wavelength of the incident light, such as Figure 4 As shown, regardless of the wavelength of the incident light, the particle size can be obtained from the diffusion coefficient, which extrapolates the intensity of the incident light to 0 (zero).

[0102] in addition, Figure 4 It is a graph showing the relationship between the diffusion coefficient of a particle and the intensity of the incident light for each wavelength of the incident light.

[0103] exist Figure 4 In the diagram, line 16 represents the result when the wavelength of the incident light is 488 nm. Line 17 represents the result when the wavelength of the incident light is 633 nm.

[0104] This is the result for a dispersion of yellow pigment using PY74 (CI Pigment Yellow 74) as the particles. The solvent for the above yellow pigment dispersion is water.

[0105] The above description describes analytical examples of low-concentration particle dispersion systems, such as 0.1–0.001 vol%, using autocorrelation functions. Furthermore, the diffusion coefficient was used in the above analytical examples, but as… Figure 3 As shown, the inverse of the particle size can also be used instead of the diffusion coefficient. The particle size, which is independent of the incident light intensity, can be obtained by extrapolating the value of the inverse of the particle size to the case where the incident light intensity is 0 (zero).

[0106] In the above explanation, an autocorrelation function was used. However, even when using a high-concentration particle dispersion system with a power spectrum, such as 1 to 20 vol%, the particle size, which is independent of the incident light intensity, can be obtained by extrapolating the incident light intensity to 0 (zero), just like the autocorrelation function described above.

[0107] like Figure 5 As shown, the power spectrum varies with each incident light intensity. The power spectrum also exhibits a dependence on the incident light intensity. Furthermore, Figure 5 This is the result of measuring the dispersion of a blue pigment. The blue pigment is PB15:6 (CI Pigment Blue 15:6).

[0108] By performing an inverse Fourier transform on the power spectrum, the autocorrelation function can be obtained. As mentioned above, the diffusion coefficient can be obtained from the autocorrelation function, and the particle size can be obtained from the diffusion coefficient.

[0109] For example, such as Figure 6 As shown, there is a linear relationship between the reciprocal of the particle size obtained from power spectrum analysis and the incident light intensity. The particle diffusion coefficient and incident light intensity obtained from power spectrum analysis are derived from... Figure 6 The line 18 shown represents this. Additionally, in... Figure 6 In this case, the vertical axis is set to the reciprocal of the particle diameter. However, as mentioned above, even if the vertical axis is set to the diffusion coefficient, there is still a linear relationship between the diffusion coefficient and the incident light intensity.

[0110] Thus, even when using power spectra, similar to the results obtained by low coherence dynamic light scattering (LC-DLS) analysis, even particles with light-absorbing properties can obtain particle sizes independent of incident light intensity, based on the diffusion coefficient extrapolated to a value of 0 (zero) of the incident light intensity.

[0111] For example, high-concentration particle dispersions of 1–20% by volume can be determined using low-coherence dynamic light scattering (LC-DLS). In LC-DLS, the diffusion coefficient is obtained by fitting a theoretical formula to the power spectrum. Alternatively, the diffusion coefficient can be obtained by performing an inverse Fourier transform on the power spectrum to obtain the autocorrelation function, and then fitting the theoretical formula to it.

[0112] Next, the phenomenon of particles absorbing light and their temperature rising will be explained.

[0113] The diffusion coefficient D' when a local temperature rise occurs near the particle due to light absorption and the system reaches equilibrium is represented by the following equation (3). In the following equation (3), T´ is the temperature of the solvent after light absorption, and η´ is the viscosity of the solvent at temperature T´. In this case, it is assumed that the temperature rise only occurs locally near the particle and cannot be captured by the thermometer attached to the device. In this case, the thermometer attached to the device displays the temperature T0. If the particle size measured by dynamic light scattering (DLS) is d´, the relationship between the particle size d´ and the above diffusion coefficient D' is represented by the following equation (4). Therefore, the following equation (5) can be obtained from equations (2) and (3).

[0114] [Formula 2]

[0115]

[0116] [Formula 3]

[0117]

[0118] [Formula 4]

[0119]

[0120] Here, if the temperature rise near the particle caused by light absorption is denoted as ΔT, then the temperature rise is represented by the following equation (6).

[0121] (6)

[0122] Moreover, when the following equation (7) holds true between the incident light intensity I and the temperature rise ΔT of the particle caused by light absorption, if equations (5) and (6) are substituted into equation (4), then the following equation (8) is obtained.

[0123] (7)

[0124] [Formula 5]

[0125]

[0126] The relationship between the viscosity of the solvent and the temperature of the solvent is expressed by the Andrade equation (9) below. In addition, in the following equation (9), B is the proportionality constant, E is the flow activation energy, and R is the gas constant.

[0127] [Formula 6]

[0128]

[0129] Here, we define the following equation (10) for 1 / η´. Then, if we perform a Taylor expansion of the following equation (10) on the temperature, we can obtain the following equation (11). Then, if we substitute the following equation (10) into equation (7), we can obtain the following equation (12).

[0130] [Formula 7]

[0131]

[0132] [Formula 8]

[0133]

[0134] [Formula 9]

[0135]

[0136] Here, in equation (12), when ΔT < T0, the reciprocal of the particle size is linear with respect to the incident light intensity I. In this case, it becomes equation (13). In equation (13), if only the linear term is considered, it becomes equation (14).

[0137] [Formula 10]

[0138]

[0139] [Formula 11]

[0140]

[0141] [Formula 12]

[0142]

[0143] Let the term proportional to the incident light intensity I in equation (12) be β, and define β as in equation (15) below. Then, 1 / d´ can be expressed by equation (16) below. If d0 is solved using equation (16) below, equation (17) below can be obtained.

[0144] [Formula 13]

[0145]

[0146] [Formula 14]

[0147]

[0148] Furthermore, if equation (16) is multiplied by kBT / (3πη), then the following equation (16-1) can be obtained. In equation (16-1), D´ and D0 are diffusion coefficients.

[0149] (16-1)

[0150] (17)

[0151] From equation (16-1), it can be seen that the above... Figure 2 The slope of the line 12, which shows the dependence of incident light intensity, is βD0, and the intercept of line 12 is the diffusion coefficient D0. Therefore, the aforementioned β can be obtained from the slope βD0 and the intercept, i.e., the diffusion coefficient D0. Using the incident light intensity I and the diffusion coefficient D´ at incident light intensity I, the diffusion coefficient D0 can be obtained from equation (16-1), and the particle size d0 can be obtained from equation (1). The aforementioned β is an index value representing the temperature dependence of the particle size.

[0152] The particle size d´ at incident light intensity I can also be obtained using the diffusion coefficient D´ according to equation (4).

[0153] In addition, in the above Figure 2 When the vertical axis is the reciprocal of the particle size, for example, in Figure 3 In equation (16), it can be seen that the slope of the straight line 12, which represents the dependence of incident light intensity, is β / d0, and the intercept of the straight line 12 is the particle size d0. Therefore, the above β can be obtained from the slope β / d0 and the intercept, i.e., the particle size d0. Using the incident light intensity I and the particle size d´ at the incident light intensity I, the particle size d0 can be obtained from equation (16). The above β is an index value representing the temperature dependence of the particle size.

[0154] The particle size d´ at incident light intensity I can also be obtained using the diffusion coefficient D´ according to equation (4).

[0155] Furthermore, according to equation (14) and Figure 2 Given the particle size d´ and d0 at any incident light intensity I, and knowing the viscosity-dependent constant E / R and temperature T0 of the solvent, the temperature rise ΔT at each incident light intensity can be obtained. Therefore, by calculating the proportionality coefficient α between the incident light intensity I and the temperature rise ΔT in equation (7), the actual temperature in the measurement, T´ = T0 + ΔT, can be determined. In this case, by measuring the particle size at any incident light intensity, the particle size d0 is obtained from equation (3). Furthermore, the temperature dependence of the solvent viscosity is known. As can be seen from the above, it is possible to accurately measure the particle size of particles contained in a dispersion containing particles with light-absorbing properties.

[0156] The above describes the case of monodisperse particles. The method described above can also be applied to particles with a particle size distribution P(d). The steps are explained below.

[0157] In the case of a particle size distribution P(d), equation (2) is represented by the following equation (18). The left side of the following equation (18) is the sum of the particle size d from 0 to ∞. A(d) is the frequency distribution of the component of particle size d, and ΣA(d) represents the particle size distribution. Furthermore, D(d) is the diffusion coefficient of particle size d. In addition, the relationship between the diffusion coefficient D(d) and the particle size d is represented by equation (1).

[0158] [Formula 15]

[0159]

[0160] Furthermore, when the particles have a particle size distribution, as described above, by fitting the exponential function exp(-2Dq) 2 τ), which can obtain the particle size distribution A(d).

[0161] The average value of the particle size distribution A(d) is, for example, the average value under the scattering intensity reference, and therefore the average particle size. Therefore, it is assumed that the particle diffusion coefficient has a linear dependence on the incident light intensity, such as... Figure 2 As shown, the average value of the particle size distribution A(d) is plotted relative to the incident light intensity I. From this, a straight line representing the dependence of the incident light intensity on the average particle size can be obtained. The slope of this line representing the dependence of the incident light intensity is β / d0, and the particle size at which the incident light intensity is 0 (zero) is d0. d0 corresponds to the intercept of the line. β can be calculated from β / d0, which represents the slope, and d0, which is the intercept.

[0162] Then, for the obtained particle size distribution A(d), particle size distribution A(d) is set as particle size distribution A(d0) using equation (17), thereby obtaining particle size distribution A(d0) that takes into account the dependence of incident light intensity. Thus, the particle size distribution of contained particles in a dispersion containing particles with light-absorbing properties can be determined with high precision.

[0163] Furthermore, as mentioned above, when fitting equation (18) to... Figure 1 When plotting the autocorrelation function, you can use... Figure 1 A graph of any autocorrelation function. When the granularity distribution A(d) is set as granularity distribution A(d0) using equation (17) expressed as d0=(1+β)·I·d´, a graph of the autocorrelation function used for fitting is shown in the reference. Figure 1 The intensity of the incident light is set as I in equation (17).

[0164] Furthermore, as mentioned above, according to equation (14) and Figure 2 Given the particle size d' and d0 under any incident light intensity I, this formula is applicable to particles with a particle size distribution P(d). In this case, for example, equation (18) can be fitted to the known particle size distribution P(d) as described above. Figure 1 The autocorrelation function is plotted in the graph. Then, when the particle size is determined from the diffusion coefficient D, as shown in Equation (3), the particle size distribution A(d0) taking into account the influence of incident light can be obtained by using the temperature T´ and the viscosity η´ of the solvent at temperature T´. It can be seen that the particle size distribution of the contained particles in a dispersion containing particles with the property of absorbing light can be determined with high precision.

[0165] Furthermore, the Andreid formula is an example in the derivation of the above formula, and it is not solely dependent on the Andreid formula. If the temperature dependence of the viscosity of the solvent or dispersion system is known, the particle size can be obtained in the same way as when using the Andreid formula.

[0166] (Example of a light measurement device)

[0167] Next, the optical measurement apparatus used in the optical measurement method will be described.

[0168] Figure 7 This is a schematic diagram illustrating a first example of a light measuring apparatus according to an embodiment of the present invention.

[0169] Figure 7 The optical measurement device 20 shown is an optical measurement device utilizing low-coherence dynamic light scattering (LC-DLS). The optical measurement device 20 uses a Mach-Zehnder interferometer.

[0170] The light measuring device 20 includes a light source 22, a first coupler 24, a circulator 26, a collimating lens 28, an objective lens 30, a sample cell 32 containing a dispersion liquid Lq containing particles, a second coupler 34, a detector 36, and a processing unit 38.

[0171] Furthermore, the light measuring device 20 includes a first collimating lens 40, a modulator 42, and a second collimating lens 43. The first collimating lens 40, the modulator 42, and the second collimating lens 43 constitute a phase modulation unit 44.

[0172] Light source 22 has the function of changing the intensity of incident light (not shown) before it is incident on the dispersion Lq in sample cell 32. Light source 22 emits, for example, low-coherence light. Low-coherence light, unlike monochromatic laser beams, is light with a bandwidth. Light source 22 can be, for example, a xenon lamp, a superluminescent diode (SLD), an LED (light emitting diode), or a supercontinuum (SC) light source.

[0173] The first coupler 24 branches the emitted light from the light source 22 and has multiple input and output ports. For example, the first coupler 24 has a configuration of 2 inputs and 2 outputs, in which light is input to end face 24a and output from end face 24b.

[0174] The first coupler 24 is preferably capable of changing the branching ratio of the light according to the object being measured.

[0175] The light source 22 is connected to the end face 24a of the first coupler 24 via an optical fiber 23a. Furthermore, an optical fiber 23b is connected to the end face 24a of the first coupler 24, but the optical fiber 23b is not connected to any component other than the first coupler 24.

[0176] The emitted light from the light source 22 is branched through the first coupler 24 and emitted into optical fibers 23c and 23d connected to the end face 24b.

[0177] The first coupler 24 branches the emitted light from the light source 22 at an intensity ratio of, for example, 99:1, and outputs it to optical fibers 23c and 23d. Regarding the branching ratio of the emitted light from the light source 22, calculated in intensity terms, for example, 99% of the light is output to optical fiber 23c, and 1% of the light is output to optical fiber 23d. The light from optical fiber 23c becomes the incident light of the dispersion liquid Lq, and the light from optical fiber 23d becomes the reference light.

[0178] The first coupler 24 is connected to the circulator 26 via optical fiber 23c. The circulator 26 is connected to both optical fiber 23c and optical fiber 23f.

[0179] Circulator 26 is an optical path converter that guides light from fiber 23c to fiber 23e and incident light from fiber 23e to fiber 23f. As circulator 26, for example, a circulation pump known for use in dynamic light scattering measurement devices can be appropriately utilized.

[0180] Optical fiber 23e is connected to collimating lens 28. Objective lens 30 is disposed on the exit side of collimating lens 28. Sample cell 32 is disposed on the side of objective lens 30 opposite to collimating lens 28.

[0181] Collimating lens 28 sets the light from optical fiber 23e to be parallel. Objective lens 30 focuses the incident light that has passed through optical fiber 23e and collimating lens 28 onto the dispersion liquid Lq. That is, objective lens 30 illuminates the dispersion liquid Lq with incident light from light source 22.

[0182] The outgoing light from light source 22 is incident on the dispersion liquid Lq via optical fiber 23a, first coupler 24, optical fiber 23c, circulator 26, optical fiber 23e, collimating lens 28, and objective lens 30. At this time, scattered light is generated in the dispersion liquid Lq.

[0183] The scattered light generated in the dispersion Lq is guided sequentially through objective lens 30, collimating lens 28, optical fiber 23e, and circulator 26 to optical fiber 23f. Optical fiber 23f is connected to the second coupler 34.

[0184] Objective lens 30 focuses the incident light into the dispersion Lq and captures the scattered light generated by the incident light in the dispersion Lq. The magnification of objective lens 30 is not particularly limited; for example, a 10x objective lens can be used. Furthermore, objective lens 30 is not necessarily required; the light measuring device 20 can be configured without objective lens 30.

[0185] Furthermore, it is preferable to provide a wavelength filter on the optical fiber 23f for cutting off the fluorescence generated in the dispersion Lq (sample).

[0186] The second coupler 34 couples the input light and has multiple input / output ports. For example, the second coupler 34 has 2 inputs and 2 outputs, and is configured such that light is input to end face 34a and output from end face 34b. Optical fibers 23f and 23g are connected to end face 34a. Optical fibers 23h and 23i are connected to end face 34b. Optical fibers 23h and 23i are connected to detector 36.

[0187] The optical fiber 23d, which is connected to the first coupler 24, is connected to the first collimating lens 40. The first collimating lens 40, the modulator 42, and the second collimating lens 43 are arranged in that order. The second collimating lens 43 is connected to the second coupler 34 via the optical fiber 23g.

[0188] The first collimating lens 40 and the second collimating lens 43 make the incident light parallel.

[0189] Modulator 42 applies phase modulation, for example using an electro-optic modulator (EOM).

[0190] Light collimated into parallel light by the first collimating lens 40 is incident on the modulator 42, and after phase modulation is applied by the modulator 42, it is collimated into parallel light by the second collimating lens 43 and emitted into the optical fiber 23g. Reference light is obtained through the first collimating lens 40, the modulator 42 and the second collimating lens 43, that is, through the phase modulation unit 44.

[0191] The scattered light is input to the second coupler 34 via optical fiber 23f. The reference light is input to the second coupler 34 via optical fiber 23g. Interference occurs between the reference light and the scattered light in the second coupler 34. The second coupler 34, for example, branches the interference light with a 1:1 intensity ratio and outputs the two beams to the detector 36. Preferably, the second coupler 34 is capable of varying the branching ratio of the light depending on the object being measured.

[0192] Detector 36 is connected to processing unit 38. The differential light obtained by detector 36 (described later) is output to processing unit 38. For example, a balanced detector is used as detector 36. Measurement unit 37 is composed of first coupler 24, circulator 26, collimating lens 28, objective lens 30, second coupler 34, detector 36, and optical fibers 23a to 23i.

[0193] Furthermore, the configuration of optical fibers 23a to 23i is not particularly limited as long as it can transmit light, and known optical fibers can be appropriately utilized.

[0194] Detector 36 extracts the difference between the two beams output from the second coupler 34. This removes common-mode noise, obtaining a signal of scattered light containing interference components. Detector 36 converts the signal of the scattered light from the difference between the two beams into an electrical signal and outputs this converted signal to processing unit 38. Thus, the scattered light signal is obtained by detector 36, i.e., measurement unit 37, thereby obtaining scattering intensity data. The scattering intensity data represents the scattering intensity of the scattered light.

[0195] In the light measurement apparatus 20, the scattered light obtained by changing the intensity of the incident light and then incident on the dispersion Lq is measured multiple times, and the scattering intensity data is obtained by the measurement unit 37 at each measurement. Thus, the measurement unit 37 obtains multiple scattering intensity data.

[0196] The processing unit 38 performs data processing and analysis.

[0197] The processing unit 38 converts multiple scattering intensity data into multiple scattering electric fields or time-varying scattering intensity characteristic data. Then, it uses the obtained multiple scattering electric fields or time-varying scattering intensity characteristic data to determine the particle size.

[0198] Furthermore, the processing unit 38 uses the obtained time-varying characteristic data of multiple scattering electric fields or scattering intensities to determine the particle size distribution.

[0199] The processing unit 38 has a conversion unit 38a, which converts multiple scattering intensity data output from the detector 36 as described above into multiple scattering electric field or scattering intensity time variation characteristic data.

[0200] In this way, the scattered light signals obtained from multiple measurements are obtained, and multiple scattered intensity data are converted to obtain multiple time-varying characteristic data of scattered electric field or scattered intensity.

[0201] Specifically, in the conversion unit 38a of the processing unit 38, the scattering intensity data is converted into multiple scattering electric fields or time-varying characteristic data of scattering intensity. The time-varying characteristic data of scattering electric fields or scattering intensity are, for example, autocorrelation functions or power spectra.

[0202] The autocorrelation function was calculated using known methods based on the scattering intensity data of the dispersion. Similarly, the power spectrum was also calculated using known methods based on the scattering intensity data of the dispersion.

[0203] The particle size calculation unit 38b is equipped with a particle size calculation unit 38a that uses time-varying characteristic data of multiple scattering electric fields or scattering intensities obtained by the conversion unit 38a to determine the particle size.

[0204] In the particle size calculation unit 38b, as described above Figure 1 As shown, the autocorrelation function is obtained for each incident light intensity, and the exponential function exp(-2Dq) is fitted. 2 The particle size is determined by using τ. The diffusion coefficient D is then calculated using the above fitting method, and the particle size is obtained based on the diffusion coefficient D.

[0205] Furthermore, in the particle size calculation unit 38b, as described above... Figure 2 As shown, the particle size can also be calculated by assuming that the diffusion coefficient of the particle depends linearly on the intensity of the incident light. In this case, in the particle size calculation unit 38b, multiple autocorrelation functions are analyzed to obtain multiple diffusion coefficients for the particle. Then, as described above... Figure 2 As shown, the relationship between the particle diffusion coefficient and the incident light intensity is determined. Next, the particle size is obtained by extrapolating the incident light intensity to 0 (zero) using the diffusion coefficient. Thus, a particle size independent of the incident light intensity is obtained. Therefore, the particle size of particles contained in a dispersion containing particles with light-absorbing properties can be measured with high precision.

[0206] Furthermore, the particle size calculation unit 38b can also obtain the second temperature after the temperature of the particles at the first temperature rises due to light absorption by the incident light. Using the formula representing the diffusion coefficient when the temperature rise occurs, the particle size of the particles at the second temperature is calculated based on the particle size obtained by the particle size calculation unit 38b.

[0207] Here, the first temperature refers to the temperature before the temperature rises due to light absorption. For example, if the particles are dispersed in a dispersion Lq, it is the temperature of the dispersion Lq before light absorption.

[0208] Specifically, the second temperature is obtained by means of a thermometer or the like after the temperature rises due to the absorption of incident light.

[0209] In this case, as described above, given the particle size d´ and d0 at any incident light intensity I, and knowing the constant E / R related to the solvent viscosity and the temperature T0, the temperature rise ΔT at each incident light intensity can be obtained. Therefore, the proportionality coefficient α between the incident light intensity I and the temperature rise ΔT in equation (7) can be calculated, yielding the actual temperature T´ = T0 + ΔT in the measurement. Temperature T0 is the first temperature, and temperature T´ is the second temperature. Equation (3) represents the diffusion coefficient when a temperature rise occurs. In this case, by measuring the particle size at any incident light intensity, the particle size at the second temperature can be obtained from equation (3), for example, the particle size at temperature T´ can be obtained.

[0210] The particle size distribution calculation unit 38c has a particle size distribution calculation unit that calculates the particle size distribution using time-varying characteristic data of multiple scattered electric fields or scattering intensities obtained by the conversion unit 38a.

[0211] Equation (18) above represents the autocorrelation function and the exponential function of the particle size distribution A(d) including particle size d, exp(-2Dq). 2 The relationship between τ). In the particle size distribution calculation unit 38c, the exponential function exp(-2Dq) is fitted to the autocorrelation function. 2 The particle size distribution A(d) can be determined by fitting the particle size distribution A(d0). Furthermore, the particle size distribution A(d0) can also be determined. The fitting method and the method for determining the particle size distribution A(d0) are described above. As can be seen from the above, the particle size distribution of particles in a dispersion containing particles with light-absorbing properties can be determined with high precision.

[0212] The particle size distribution calculation unit 38c can use the time variation characteristic data of multiple scattering electric fields or scattering intensities obtained by the conversion unit 38a to calculate the index value representing the temperature dependence of the particle size, and use the index value representing the temperature dependence of the particle size to correct the particle size distribution.

[0213] The index value representing the temperature dependence of the particle size of the above particles is β, as defined by equation (15).

[0214] As described above, the particle size distribution calculation unit 38c fits equation (18) to... Figure 1 The granularity distribution A(d) is obtained from the graph of the autocorrelation function. Then, for the obtained granularity distribution A(d), the graph of the autocorrelation function used for fitting is obtained by using the same formula as in equation (17), which is expressed by d0 = (1 + β) · I · d (see reference). Figure 1 The incident light intensity is taken as I in the equation d0 = (1 + β)·I·d, and the obtained particle size distribution A(d) is corrected to A(d0). Thus, a particle size distribution A(d0) that takes into account the dependence of incident light intensity can be obtained.

[0215] In addition, regarding Figure 1 The graph of the autocorrelation function can be obtained by calculating the autocorrelation function for each incident light intensity for particles with a particle size distribution.

[0216] Furthermore, the particle size distribution calculation unit 38c can also obtain the second temperature after the temperature of the particles rises due to light absorption by the incident light at the first temperature, and use the second temperature in the diffusion coefficient obtained from the time variation characteristics data of multiple scattering electric fields or scattering intensities to calculate the particle size distribution.

[0217] In this case, as described above, by fitting equation (18) to Figure 1The particle size distribution is obtained from the graph of the autocorrelation function. At this time, when calculating the particle size based on the diffusion coefficient D, as shown in Equation (3), the viscosity η' of the solvent at temperature T´ (i.e., the second temperature) and temperature T´ is used. Thus, the particle size distribution A(d0) taking into account the influence of incident light can be obtained.

[0218] The processing unit 38 calculates the particle size distribution as described above by executing a program (computer software) stored in ROM (Read Only Memory) or the like. The processing unit 38 can be a computer in which each part functions by executing the program as described above, or it can be a dedicated device in which each part is composed of dedicated circuits, or it can be a server so that it can be executed in the cloud.

[0219] The aforementioned computers, dedicated devices, and servers, for example, have a processor. The processor can be composed of one or more hardware components, and the type of hardware is not limited. For example, the processor can be composed of programmable logic devices such as CPUs (Central Processing Units), MPUs (Micro Processing Units), FPGAs (Field Programmable Gate Arrays), dedicated circuits for performing specific processes such as ASICs (Application Specific Integrated Circuits), GPUs (Graphics Processing Units), or NPUs (Neural Processing Units). Furthermore, the processor has units or means that execute the various processes described in this embodiment. Moreover, the type of hardware can also be a combination of different types of hardware. When multiple hardware components are configured to execute one or more processes of a certain processor, these multiple hardware components can exist in physically separate devices or in the same device. Furthermore, in any embodiment, the order of the processor-based processes is not limited to the above-described order and can be appropriately varied. Additionally, the hardware is composed of circuits, such as those combining semiconductor elements.

[0220] The sample cell 32 is, for example, a cuboid or cylindrical container made of optical glass or optical plastic. A dispersion Lq containing particles, which is the object of measurement, is contained in the sample cell 32. Incident light irradiates the dispersion Lq.

[0221] The sample cell 32 can be disposed inside a liquid immersion bath (not shown). The liquid immersion bath is used to eliminate the refractive index difference with the surrounding environment or to homogenize the temperature. As a liquid immersion bath, a known liquid immersion bath can be appropriately used. Furthermore, the temperature of the sample cell 32 can also be adjusted by bringing the sample cell 32 into contact with the metal that contacts the Peltier element.

[0222] As described above, the light measuring device 20 measures the scattered light generated by the scattering of incident light from the light source 22 in the dispersion liquid Lq by changing the incident light intensity. The incident light intensity is the measurement parameter.

[0223] (The second example of a light measurement device)

[0224] The light measuring device 20 is not limited to Figure 7 The configuration shown can also be Figure 8 The light measuring device 20a shown is shown.

[0225] Figure 8 This is a schematic diagram illustrating a second example of a light measuring apparatus according to an embodiment of the present invention. Figure 8 In the middle, to and Figure 7 The same structures as those in the light measuring device 20 shown are labeled with the same symbols, and their detailed descriptions are omitted.

[0226] Figure 8 The light measuring device 20a shown is... Figure 7 The difference between the light measuring device 20 shown and the light measuring device 20a is that it has a measuring unit 46 for measuring the intensity of incident light. In the light measuring device 20a, the measuring section 37 is composed of a first coupler 24, a circulator 26, a collimating lens 28, an objective lens 30, a second coupler 34, a third coupler 45, the measuring unit 46, a detector 36, and optical fibers 23a to 23m.

[0227] The light measuring device 20a, by providing the measuring unit 46, can more accurately measure the intensity of incident light incident on the sample cell 32. Therefore, when using the above-mentioned... Figure 2 With the diffusion coefficient of the particles showing dependence on the intensity of incident light, or the inverse of the particle size showing dependence on the intensity of incident light, more accurate measurements of particle size and particle size distribution can be made.

[0228] In the light measurement apparatus 20a, specifically, as Figure 8 As shown, a third coupler 45 is provided on optical fiber 23e connected to circulator 26. The third coupler 45 has the same configuration as the first coupler 24, with 2 inputs and 2 outputs, and is configured to input light to end face 45a and output light from end face 45b. Optical fibers 23e and 23j are connected to end face 45a. Optical fibers 23k and 23m are connected to end face 45b.

[0229] Fiber 23k is connected to collimating lens 28. Fiber 23m is connected to measuring unit 46.

[0230] The third coupler 45 branches the light from fiber 23e to fibers 23k and 23m. Fiber 23k is connected to collimating lens 28, and the light incident on fiber 23k is used for particle measurement. Therefore, regarding the branching ratio of the third coupler 45, fiber 23k is preferably larger than fiber 23m. Furthermore, the light incident on fiber 23m is used to measure the intensity of the incident light. Therefore, the proportion of light incident on fiber 23 is not particularly limited as long as the intensity can be measured by the measurement unit 46. Furthermore, the placement of the measurement unit 46 is not particularly limited as long as the intensity of the light from the light source 22 can be measured.

[0231] The measuring unit 46 is connected to the processing unit 38. The incident light intensity measured by the measuring unit 46 is output to the processing unit 38.

[0232] The configuration of the measuring unit 46 is not particularly limited as long as it can measure the intensity of the incident light. For example, a photomultiplier tube, a photodiode, an avalanche photodiode, and a time correlator can be used for the measuring unit 46.

[0233] In addition, an optical fiber 23j is connected to the end face 45a of the third coupler 45, but the optical fiber 23j is not connected to any component other than the third coupler 45.

[0234] Furthermore, the structure of optical fibers 23a to 23m is not particularly limited as long as it can transmit light, and known optical fibers can be appropriately utilized.

[0235] Furthermore, the aforementioned photometric devices 20 and 20a are both photometric devices that utilize low coherence dynamic light scattering (LC-DLS), but they are not limited to this. As long as the intensity of the light source 22 can be changed, a photometric device utilizing dynamic light scattering (DLS) can be used.

[0236] (The first example of a photometric method)

[0237] The light measurement is performed based on the measurement principle described above. During the light measurement, for example, the above-described method is used... Figure 7 The light measuring device 20 shown and Figure 8 The light measuring device 20a shown is shown.

[0238] The first example of a photometric method is a photometric method for a dispersion containing particles.

[0239] In the first example of the photometric method, firstly, the scattered intensity of the scattered light obtained by changing the intensity of the incident light and then incident on the dispersion Lq is measured multiple times to obtain multiple scattered intensity data (measurement procedure).

[0240] In this case, as Figure 7 The light source 22 shown is, for example, a supercontinuum light source used to measure a dispersion Lq containing particles.

[0241] The outgoing light from the light source 22 is branched by the first coupler 24 at an intensity ratio of 99:1, and 99% of the branched light is output to the optical fiber 23c. The light is then focused by the objective lens 30 via the circulator 26, the optical fiber 23e, and the collimating lens 28, so that the incident light is incident on the dispersion liquid Lq.

[0242] The incident light is scattered by the particles and the scattered light is captured by the objective lens 30 and passed through the collimating lens 28 and the optical fiber 23e. It is then output to the optical fiber 23f through the circulator 26, so that the scattered light is input to the second coupler 34.

[0243] On the other hand, 1% of the light branched by the first coupler 24 is used as reference light. The branched 1% of the light is output to the optical fiber 23d, and is phase-modulated by the first collimating lens 40, the modulator 42 and the second collimating lens 43. It is then input to the second coupler 34 as reference light through the optical fiber 23g.

[0244] In the second coupler 34, the reference light and the scattered light interfere to obtain interference light. Then, the interference light is branched, for example, with an intensity ratio of 1:1, and the two beams are output to the detector 36.

[0245] In detector 36, the difference between the two beams output from the second coupler 34 is extracted. This removes common-mode noise, obtaining a signal of scattered light containing interference components. The signal of the scattered light from the difference between the two beams is converted into an electrical signal, thereby obtaining scattering intensity data. Detector 36 outputs the scattering intensity data to processing unit 38.

[0246] By changing the intensity of the incident light and performing the above process multiple times, the scattered light signal is obtained by the detector 36, i.e. the measurement unit 37, during each measurement, and the scattered intensity data is further obtained, thereby obtaining multiple scattered intensity data.

[0247] Next, as described above, multiple scattering intensity data obtained from the scattered light signal obtained through the measurement process based on the measurement unit 37 are converted into multiple time-varying characteristic data of scattering electric fields or scattering intensities (conversion process). The multiple time-varying characteristic data of scattering electric fields or scattering intensities are, for example, multiple autocorrelation functions or multiple power spectra.

[0248] Specifically, the conversion unit 38a uses known methods to convert multiple scattering intensity data into multiple scattering electric fields or time-varying characteristic data of scattering intensity, such as multiple autocorrelation functions or multiple power spectra.

[0249] The particle size is determined using time-varying characteristic data of multiple scattering electric fields or scattering intensities obtained through the conversion process (particle size calculation process).

[0250] Specifically, in the particle size calculation unit 38b, the autocorrelation function or power spectrum obtained by the conversion unit 38a of the processing unit 38 is used. For example, as Figure 1 As shown, the autocorrelation function is used.

[0251] Equation (2) above represents the autocorrelation function and the exponential function exp(-2Dq) 2 The relationship between τ). In the particle size calculation unit 38b, the exponential function exp(-2Dq) is fitted to the autocorrelation function. 2 The diffusion coefficient D is obtained using τ. Regarding the fitting, see above. The particle size is then obtained based on the diffusion coefficient D obtained as described above.

[0252] Furthermore, the particle size calculation process can also be performed as described above. Figure 2 As shown, assuming that the diffusion coefficient of a particle is linearly dependent on the intensity of incident light, the time-varying characteristics of multiple scattering electric fields or scattering intensities are analyzed to determine the relationship between the particle size or the diffusion coefficient of the particle and the intensity of incident light, thereby determining the particle size.

[0253] Specifically, it is assumed that the relationship between the particle diffusion coefficient obtained by analyzing the autocorrelation function and the incident light intensity is linear, for example, as... Figure 2 The particle size is obtained by representing it with straight line 12.

[0254] In this case, the diffusion coefficient of the particle is determined by analyzing multiple autocorrelation functions or multiple power spectra, for example, for each incident light intensity. Then, the diffusion coefficient of the particle is plotted for each incident light intensity, and the relationship between the particle's diffusion coefficient and the incident light intensity is determined. Next, the diffusion coefficient when the incident light intensity is 0 is determined. The particle size is obtained from this diffusion coefficient. This particle size is independent of the incident light intensity. In this way, even particles with light-absorbing properties can have their particle size determined.

[0255] Furthermore, even if the particle absorbs light and its temperature rises, the particle size can still be calculated as follows.

[0256] In this case, the particle at the first temperature is obtained after its temperature rises due to light absorption by the incident light, resulting in a second temperature. Next, the particle size at the second temperature is calculated using the formula representing the diffusion coefficient at which the temperature rise occurs, based on the particle size obtained in the particle size calculation process.

[0257] The first temperature is as described above. The second temperature, after the temperature rises due to light absorption by the incident light, is obtained using a thermometer or the like. If the temperature rise can be obtained, the particle size at the second temperature can be calculated using equation (3), which represents the diffusion coefficient at the aforementioned temperature rise. Furthermore, as described above, T´ is the temperature after light absorption, which in this case is the second temperature. η´ is the viscosity of the solvent at temperature T´, which in this case is the viscosity at the second temperature.

[0258] Furthermore, the temperature rise is defined by equations (6) and (7) above, and therefore they can be used. The particle size at the second temperature can be determined using equation (17) above. In this case, d´ in equation (17) above is the particle size at the second temperature. Regarding β, as described above, according to the representation... Figure 2 The slope β / d0 and the intercept, i.e. the particle size d0, of the straight line showing the dependence of incident light intensity are obtained.

[0259] (The second example of a photometric method)

[0260] The above descriptions of monodisperse particles have been provided, but it is also possible to determine the particle size distribution for particles with a particle size distribution.

[0261] As described above, in the particle size distribution calculation unit 38c, it is possible to fit the exponential function exp(-2Dq) to the autocorrelation function. 2 τ) is used to calculate the particle size distribution A(d) (particle size distribution calculation process).

[0262] The particle size distribution calculation process may also include: a process of using time-varying characteristic data of multiple scattering intensities to determine an index value representing the temperature dependence of particle size; and a process of using the index value representing the temperature dependence of particle size to correct the particle size distribution obtained in the particle size distribution calculation process.

[0263] As described above, the index value representing the temperature dependence of the particle size is β, defined by equation (15). As described above, β can be determined based on the temperature dependence of the particle size. Figure 2 The slope βD0 of the straight line showing the dependence of incident light intensity and the diffusion coefficient D0 as the intercept are obtained.

[0264] Moreover, using formula (17), Figure 1 The incident light intensity of the graph used in the figure is taken as I in Equation (17), and the obtained particle size distribution A(d) is corrected to A(d0), thereby obtaining the particle size distribution A(d0) that takes into account the dependence of incident light intensity.

[0265] Furthermore, even within the particle size distribution, as mentioned above, the particle size distribution can be determined even when particles absorb light and their temperature rises.

[0266] In this case, there is a process of obtaining a second temperature after the particles have a first temperature and their temperature rises due to light absorption by the incident light. In the particle size distribution calculation process, the particle size distribution is obtained by using the second temperature in the diffusion coefficient obtained from the time variation characteristics data of multiple scattering electric fields or scattering intensities.

[0267] In particle size distribution, as long as a temperature rise is obtained, the particle size distribution can be obtained by using equation (3), which represents the diffusion coefficient at the aforementioned temperature rise, to calculate the particle size at the second temperature. In addition, as mentioned above, T is the second temperature after light absorption, and η´ is the viscosity at the second temperature after light absorption.

[0268] Furthermore, as mentioned above, the temperature rise is defined by equations (6) and (7) above, and therefore they can be used. The particle size at the second temperature can be determined using equation (17) above. In this case, the particle size at the second temperature can be determined, and the particle size distribution can be obtained using the particle size at the second temperature.

[0269] (The third example of a light measurement device)

[0270] Figure 9 This is a schematic diagram illustrating a third example of a light measuring apparatus according to an embodiment of the present invention. Figure 9 In the middle, to and Figure 7 The same structures as those in the light measuring device 20 shown are labeled with the same symbols, and their detailed descriptions are omitted.

[0271] Figure 9 The light measuring device 20b shown is... Figure 7 Compared to the light measurement device 20 shown, the difference lies in that it has the following function: it can measure the scattering intensity of the incident light multiple times by changing the value of at least one of the measurement parameters, the scattering angle and the measurement wavelength, thereby obtaining multiple scattering intensity data.

[0272] Figure 9 The optical measurement device 20b shown includes a low-coherence interferometer 50, a detection unit 52 having a first detection unit 52a and a second detection unit 52b, a conversion unit 54, a processing unit 38, and a storage unit 55. The optical measurement device 20b also includes a sample cell 32.

[0273] In the optical measurement apparatus 20b, the measurement unit 37 is composed of a low-coherence interferometer 50 and a detection unit 52 having a first detection unit 52a and a second detection unit 52b.

[0274] In the light measurement device 20b, the conversion unit 54 is not provided in the processing unit 38, but the conversion unit 54 has the same characteristics as described above. Figure 7 The light measuring device 20 shown has the same function as the conversion unit 38a, and has the same configuration as the conversion unit 38a.

[0275] The low-coherence interferometer 50 is an optical interferometer that uses a light source that emits low-coherence light.

[0276] The low-coherence interferometer 50, for example, has a light source 22 and four beam splitters 61a, 61b, 61c, and 61d. Each of the four beam splitters 61a, 61b, 61c, and 61d has a transmission / reflection surface 61e that splits the incident light into two or combines the two incident light waves. The transmission / reflection surface 61e is an inclined plane tilted at a 45° angle.

[0277] Furthermore, all four beam splitters 61a, 61b, 61c, and 61d are cubic beam splitters. However, the shape of the beam splitter is not limited to a cube; it can also be a flat plate.

[0278] Furthermore, the low-coherence interferometer 50 is not limited to Figure 9 The structure shown.

[0279] Four beam splitters 61a, 61b, 61c, and 61d are positioned at the vertices of a quadrilateral. The transmission and reflection surfaces 61e of beam splitters 61a and 61d, located on the diagonals, are parallel. Furthermore, the transmission and reflection surfaces 61e of beam splitters 61b and 61c, also located on the diagonals, are parallel. The transmission and reflection surfaces 61e of the four beam splitters 61a, 61b, 61c, and 61d are not parallel to the transmission and reflection surfaces 61e of their adjacent beam splitters 61a, 61b, 61c, and 61d; specifically, they are parallel in opposite directions.

[0280] Beam splitters 61a and 61c are arranged side by side, and a reflector 62 is arranged on the side of beam splitter 61c opposite to that of beam splitter 61a. A dispersion protection adjustment unit 63a and an objective lens 63b are arranged between beam splitter 61c and reflector 62, starting from the beam splitter 61c side.

[0281] The reflector 62 reflects the incident light, and the reflecting surface 62a of the reflector 62 serves as the reference surface. The reflector 62 is not particularly limited as long as it can reflect the incident light; for example, a mirror or a glass plate can be used.

[0282] The dispersion protection adjustment unit 63a compensates for the group velocity dispersion caused by the sample cell 32.

[0283] When the sample cell 32 is constructed of optical glass as described later, the dispersion protection adjustment unit 63a compensates for group velocity dispersion caused by the thickness of the optical glass constituting the sample cell 32. The group velocity dispersion of the transmitted light is compensated by a configuration in which a glass plate of the same thickness as the optical glass constituting the sample cell 32 is placed between the beam splitter 61c and the objective lens 63b. That is, the dispersion protection adjustment unit 63a adjusts the optical path length difference caused by the difference in wavelength of the reference light Lr, aligning the optical path lengths of each wavelength of the reference light Lr and the scattered light Ld.

[0284] Objective lens 63b focuses the light incident on reflector 62 onto reflector surface 62a of reflector 62.

[0285] Beam splitters 61a and 61b are arranged side by side, with an ND (Neutral Density) filter 64a positioned between them. An ND filter 64b is positioned between beam splitters 61a and 61c.

[0286] ND filters 64a and 64b adjust the light intensity to maintain a balance between the reference light Lr reflected by the reflecting surface 62a of the reflector 62 and the scattered light Ld from the sample cell 32. ND filters 64a and 64b can appropriately utilize known filters.

[0287] A sample cell 32 is disposed on the side of beam splitter 61b opposite to beam splitter 61a. An objective lens 65 is disposed between beam splitter 61b and sample cell 32 to focus the incident light Ls into the sample cell 32.

[0288] Beam splitters 61c and 61d are arranged side by side, and a first detection unit 52a is arranged on the side of beam splitter 61d opposite to that of beam splitter 61c. A polarization adjustment unit 66 is arranged between beam splitter 61d and the first detection unit 52a.

[0289] The polarization adjustment unit 66 controls the polarization state of the scattered light emitted from the beam splitter 61d and incident on the first detection unit 52a. The polarization adjustment unit 66 is, for example, composed of a polarization element. A polarization element can be appropriately used to adjust the polarization state of scattered light Ld scattered from the dispersion Lq in the sample cell 32, such as circularly polarized light, linearly polarized light, or elliptically polarized light. More specifically, for example, the polarization adjustment unit 66 is composed of a polarizer. Measurements can be performed by changing the direction of the transmission axis of the polarizer multiple times.

[0290] Beam splitters 61b and 61d are arranged side by side, and a second detection unit 52b is arranged on the side of beam splitter 61d opposite to that of beam splitter 61b.

[0291] The first detection unit 52a includes a mirror 70 and a diffraction grating 72 on which reflected light from the mirror 70 is incident. The diffraction grating 72 is an optical element that divides the incident light, including scattered light, into light of each wavelength by wavelength decomposition. The scattered light of each wavelength can be obtained through the diffraction grating 72.

[0292] Furthermore, a photodetector 73 is provided, which receives diffracted light from the diffraction grating 72 based on wavelength. The scattered light, after wavelength decomposition by the photodetector 73, is detected for each wavelength. For example, a line scan camera with a photoelectric conversion element arranged in a straight line can be used as the photodetector 73. Alternatively, a line detector with a photomultiplier tube arranged in a straight line can be used instead of a line scan camera.

[0293] The photodetector 73 of the first detection unit 52a receives diffracted light containing scattered light diffracted by the diffraction grating 72, but the diffraction angle is different for each wavelength, thereby determining the light-receiving position of the linear array camera, which serves as the photodetector 74. Therefore, in the first detection unit 52a, the wavelength is determined based on the light-receiving position of the linear array camera, which serves as the photodetector 73. In this way, the first detection unit 52a performs wavelength decomposition on the scattered light and detects the wavelength-decomposed scattered light for each wavelength. As a result, the scattering intensity of the scattered light can be easily measured at different wavelengths.

[0294] Furthermore, while a diffraction grating 72 is used to obtain light at each wavelength, it is not limited to a diffraction grating 72 as long as light at each wavelength can be obtained. For example, multiple bandpass filters with different cutoff wavelength ranges can be prepared in advance, and scattered light at each wavelength can be obtained by changing the bandpass filters. Moreover, a prism can also be used instead of a diffraction grating 72.

[0295] The second detection unit 52b includes a photodetector 74. The photodetector 74 detects the scattered light at each scattering angle. For example, a linear array camera with a photoelectric conversion element positioned in a straight line can be used as the photodetector 74. In the second detection unit 52b, the scattering angle is determined based on the light-receiving position of the linear array camera, which serves as the photodetector 74. Therefore, the scattering intensity of the scattered light can be easily measured at different scattering angles. The photodetector 74 also detects the interference light intensity at each scattering angle for the interference light between the scattered light and the reference light.

[0296] In addition, the photodetector 74 can also be used as a high-speed camera to replace the line scan camera.

[0297] Furthermore, the photoelectric conversion element used for photodetectors 73 and 74 is, for example, a photodiode.

[0298] As described above, sample cell 32 contains a dispersion Lq containing particles, which is the object of measurement. Incident light Ls irradiates the dispersion Lq. Although sample cell 32 is not shown, it can be disposed within a liquid immersion bath.

[0299] The light source 22 is positioned on the side of the beam splitter 61a opposite to the beam splitter 61b. The light source 22 illuminates the incident light Ls into the sample cell 32, causing the light emitted towards the beam splitter 61a to be incident.

[0300] As described above, the light source 22 changes the intensity of the incident light Ls to emit low-coherence light.

[0301] A spectral adjustment unit 67 and a polarization control unit 68 are provided between the light source 22 and the beam splitter 61a, starting from the light source 22 side.

[0302] The spectral adjustment unit 67 cuts off unwanted wavelength regions based on the spectrum of the incident light Ls incident from the light source 22. For example, when the near-infrared light region in the supercontinuum light source cannot be detected in the photodetector 73 of the first detection unit 52a and the photodetector 74 of the second detection unit 52b, the spectral adjustment unit 67 uses, for example, a filter that cuts off the near-infrared light region.

[0303] Furthermore, when measuring the scattering intensity at each scattering angle in the second detection unit 52b, a bandpass filter can be used in the spectral adjustment unit 67 for the purpose of limiting the wavelength range.

[0304] Furthermore, when measuring the scattered light of the dispersion Lq using light of multiple wavelengths, it is also possible to prepare multiple light sources with different emission wavelengths as light sources 22. However, by using a bandpass filter as the spectral adjustment unit 67, the wavelength region can be cut off, thus simplifying the configuration of the light source 22 and thereby simplifying the device structure.

[0305] The polarization control unit 68 controls the polarization state of the incident light and adjusts its polarization. The polarization control unit 68 is, for example, composed of a polarization element, and can appropriately use a polarization element corresponding to the polarized light irradiating the sample cell 32, such as circularly polarized light, linearly polarized light, or elliptically polarized light. Polarized light is used for the incident light when determining the shape of the particles. More specifically, the polarization control unit 68 is composed of a combination of a polarizer and a λ / 4 plate. This allows the unpolarized incident light Ls to be made circularly polarized light.

[0306] Furthermore, in the light measuring device 20b, when polarized light emitted directly from the light source 22 is used, the polarization adjustment unit 66 and the polarization control unit 68 are not necessarily required.

[0307] In the optical measuring device 20b having a first detection unit 52a and a second detection unit 52b, the scattering intensity can be easily measured at different scattering angles or different wavelengths.

[0308] Furthermore, in the light measuring device 20b, when either the scattering angle or the wavelength is used, only one of the first detection unit 52a and the second detection unit 52b needs to be present in the detection unit 52.

[0309] The light emitted from the light source 22 is split on the transmission and reflection surface 61e of the beam splitter 61a and passes through the transmission and reflection surface 61e into the beam splitter 61b. The light then passes through the transmission and reflection surface 61e of the beam splitter 61b and, as incident light Ls, irradiates the sample cell 32. The scattered light Ld generated by the scattering of the incident light Ls in the dispersion liquid Lq in the sample cell 32 is reflected on the transmission and reflection surface 61e of the beam splitter 61b and then into the beam splitter 61d.

[0310] Scattered light Ld, reflected from the light emitted from the light source 22 on the transmission and reflection surface 61e of the beam splitter 61d, is incident on the first detection unit 52a.

[0311] The light split on the transmission-reflection surface 61e of beam splitter 61a and incident into beam splitter 61c is transmitted through the transmission-reflection surface 61e into reflector 62 and reflected on the reflection surface 62a of reflector 62. This reflected light is the reference light Lr. The reference light Lr is reflected on the transmission-reflection surface 61e of beam splitter 61c and incident into beam splitter 61d. The reference light Lr, after passing through the transmission-reflection surface 61e of beam splitter 61d, is incident into the first detection unit 52a. Thus, the scattered light Ld and the reference light Lr interfere when incident into the first detection unit 52a. Furthermore, it is sufficient that at least a portion of the scattered light Ld interferes with the reference light Lr; preferably, the optical path length is adjusted so that only the scattered light Ld generated at a specific depth of the dispersion Lq interferes with the reference light Lr.

[0312] In the first detection unit 52a, the light-receiving position of the photodetector 73 is determined by the diffraction grating 72 for each wavelength, enabling the detection of interference light at each wavelength and thus obtaining data on the intensity of interference light at each wavelength. Therefore, in the conversion unit 54, scattering intensity data at a specific depth and wavelength of the dispersion Lq can be obtained from the interference spectrum of the scattered light. Furthermore, depth can be understood as the optical path length of the scattered light through the dispersion Lq.

[0313] Furthermore, the first detection unit 52a can detect interference light for each incident light intensity for incident light of a specific wavelength, and obtain data on the intensity of interference light for each incident light intensity.

[0314] Furthermore, the transmission and reflection surface 61e of the scattered light Ld transmission beam splitter 61d is incident into the second detection unit 52b.

[0315] The reference light Lr, reflected from the transmission and reflection surface 61e of the beam splitter 61d, is incident on the second detection unit 52b. Thus, the scattered light Ld and the reference light Lr interfere upon incident on the second detection unit 52b. Furthermore, it is acceptable for at least a portion of the scattered light Ld to interfere with the reference light Lr; preferably, the optical path length is adjusted so that only the scattered light generated at a specific depth in the dispersion Lq interferes with the reference light Lr.

[0316] Depending on the scattering angle θb of the dispersion Lq, the reflection position on the transmission and reflection surface 61e of the beam splitter 61b of the scattered light Ld varies, and the light-receiving position in the photodetector 74 also varies. Therefore, in the second detection unit 52b, the light-receiving position of the photodetector 74 is determined according to each scattering angle, and the interference light between the reference light and the scattered light can be detected at each scattering angle, thereby obtaining data on the interference light intensity at each scattering angle. Thus, in the conversion unit 54, for the scattered light at a specific depth of the dispersion Lq, which has the same optical path length as the reference light, scattering intensity data at a specific scattering angle can be obtained from the interference light intensity data at each scattering angle.

[0317] in addition, Figure 9 The scattering angle θb (°) is the angle based on the backscattered light with a scattering angle of 180°. The general scattering angle θ (°) with the forward scattering angle set to 0° has the relationship θ (°) = 180° - θb (°).

[0318] Furthermore, the second detection unit 52b is capable of detecting interference light at a specific scattering angle for each incident light intensity, thereby obtaining data on the intensity of interference light for each incident light intensity.

[0319] A processing unit 38 is connected to the conversion unit 54, and a storage unit 55 is connected to the conversion unit 54 and the processing unit 38.

[0320] The conversion unit 54 extracts multiple values ​​that are proportional to the scattering intensity or electric field of scattered light of a specific wavelength from the interference light intensity data detected by the first detection unit 52a, or extracts multiple values ​​that are proportional to the scattering intensity or electric field of light of a specific scattering angle from the interference light intensity data detected by the second detection unit 52b.

[0321] Furthermore, the conversion unit 54 extracts multiple values ​​proportional to the scattering intensity or electric field of the scattered light at a specific wavelength from the interference light intensity data obtained by the first detection unit 52a for each incident light intensity. Also, the conversion unit 54 extracts multiple values ​​proportional to the scattering intensity or electric field of light at a specific scattering angle from the interference light intensity data obtained by the second detection unit 52b for each incident light intensity.

[0322] Then, the conversion unit 54 converts the extracted scattering intensity data into time variation characteristic data of the scattering intensity of scattered light at a specific depth of the dispersion Lq.

[0323] The conversion unit 54 is connected to the photodetector 73 of the first detection unit 52a and the photodetector 74 of the second detection unit 52b. The conversion unit 54 acquires the light intensity data at a specific wavelength detected by the photodetector 73 of the first detection unit 52a, and extracts the scattering intensity data at multiple specific wavelengths. Then, the conversion unit 54 converts the extracted scattering intensity data into time-varying characteristic data of the scattering intensity of scattered light at a specific depth of the dispersion Lq, for example, into a power spectrum or autocorrelation function.

[0324] Furthermore, the conversion unit 54 only interferes with the scattered light generated at a specific depth of the dispersion liquid Lq by the position control of the reflector 62, as detected by the photodetector 74 of the second detection unit 52b, and acquires data on the intensity of the interference light at a specific scattering angle, and extracts the scattering intensity at multiple specific scattering angles. The conversion unit 54 converts the extracted scattering intensity data as time-varying characteristic data of the scattering intensity of the scattered light at a specific depth of the dispersion liquid Lq, for example, into a power spectrum or autocorrelation function.

[0325] Furthermore, the conversion unit 54 acquires interference light intensity data for each incident light intensity obtained by the first detection unit 52a or the second detection unit 52b, and extracts multiple scattering intensities for each incident light intensity. The conversion unit 54 converts the extracted scattering intensity data into time-varying characteristic data of the scattering intensity of scattered light at a specific depth of the dispersion Lq, for example, into a power spectrum or autocorrelation function.

[0326] The scattered light from the aforementioned dispersion Lq comprises light scattered at various depths within the dispersion Lq, with varying scattering times and intensities. To accurately determine particle size and other parameters, analysis using scattered light from specific depths within the dispersion Lq is necessary. By setting a specific depth within the dispersion Lq, it is possible to obtain, for example, single-scattered light, where light is scattered only once.

[0327] Furthermore, the analysis of the time variation characteristics of converting the extracted scattering intensity data into scattering intensity data of scattered light at a specific depth of the dispersion Lq in the conversion unit 54 will be explained later.

[0328] Furthermore, the conversion unit 54 converts the signals of multiple scattered light beams into multiple time-averaged scattered electric field data or time-averaged scattered intensity data. The time-averaged scattered electric field data or time-averaged scattered intensity data is output to the particle size distribution calculation unit 38c of the processing unit 38. The time-averaged scattered electric field data or time-averaged scattered intensity data is a time average of the scattered light signals.

[0329] As described above, the conversion unit 54 calculates the time average of multiple scattered light signals and converts them into multiple time-averaged scattered electric field data or time-averaged scattered intensity data, thereby enabling the time average of the scattered intensity to be obtained at different scattering angles or different wavelengths, for example.

[0330] For example, data showing the relationship between the scattering angle and the time-averaged scattering intensity can be obtained, which is equivalent to scattering angle-dependent data. Similarly, data showing the relationship between wavelength and the time-averaged scattering intensity can also be obtained, which is equivalent to wavelength-dependent data.

[0331] Furthermore, multiple time-averaged scattered electric field data or time-averaged scattered intensity data can be calculated values ​​based on simulation. In this case, the simulation is performed by the conversion unit 54. For example, in the above simulation, at least one of the Mie scattering theory formula, the Discrete Dipole Approximation (DDA) method, and the Finite Difference Time Domain Method (FDTD) method is used. In addition, the Discrete Dipole Approximation (DDA) method and the Finite Difference Time Domain Method (FDTD) method are equivalent to simulations based on electromagnetic wave behavior theory. Methods equivalent to simulations based on electromagnetic wave behavior theory can be appropriately utilized, and are not particularly limited to the Discrete Dipole Approximation (DDA) method and the Finite Difference Time Domain Method (FDTD) method described above.

[0332] Furthermore, the theoretical formulas are not particularly limited to the formulas mentioned above; various theoretical formulas, such as scattering theory, can be appropriately utilized.

[0333] The conversion unit 54 executes a program (computer software) stored in ROM (Read Only Memory) or the like to retrieve multiple scattering intensities as described above, and converts the retrieved scattering intensity data into time-varying characteristic data of the scattering intensity of scattered light at a specific depth of the dispersion Lq. The conversion unit 54 can be configured as a computer in which each part functions by executing the program as described above, or it can be a dedicated device in which each part is configured with dedicated circuits, or it can be configured as a server for execution in the cloud.

[0334] The processing unit 38 has the same configuration as the optical measuring device 20 described above, and includes a particle size calculation unit 38b, a particle size distribution calculation unit 38c, and a calculation unit 38d.

[0335] The particle size calculation unit 38b of the processing unit 38 uses the time variation characteristic data of scattering intensity obtained by the conversion unit 54, and compares it with the above-mentioned... Figure 7 The particle size is determined using the same method as shown in the photometric apparatus 20.

[0336] Furthermore, the processing unit 38 obtains the particle size distribution of each of the various particle types contained in the dispersion by fitting the time-varying characteristic data of scattering intensity obtained by the conversion unit 54, and the time-averaged scattering electric field data or time-averaged scattering intensity data obtained by the conversion unit 54 to a theoretical formula relating a specified particle size to scattering intensity. Various calculation methods for dynamic light scattering can be appropriately utilized in the particle size calculation of the processing unit 38. The process of obtaining the particle size distribution of each of the various particle types contained in the dispersion will be explained later.

[0337] The storage unit 55 stores at least one of the following: scattering angle dependence data on the intensity of scattered light from the known particles, and wavelength dependence data on the intensity of scattered light, which are derived from the known complex refractive index, particle size, and shape of the particles.

[0338] By storing at least one of the scattering angle dependence data and the wavelength dependence data of the scattered light intensity related to known particles in advance in the storage unit 55, a reference can be made when determining the particle size distribution or fitting the data. Therefore, for various particles, it is preferable to store at least one of the scattering angle dependence data and the wavelength dependence data of the scattered light intensity related to known particles in advance, and to build a model library in advance.

[0339] Furthermore, the storage unit 55 stores various data obtained by the conversion unit 54.

[0340] In addition, the storage unit 55 is not particularly limited as long as it can store the scattering angle dependence data and the wavelength dependence data of the scattered light intensity related to the known particles, as well as various data obtained by the conversion unit 54. For example, it can use various storage media such as hard disks or SSDs (Solid State Drives).

[0341] Similar to the aforementioned optical measuring device 20, the optical measuring device 20b changes the intensity of the incident light from the light source 22 and repeatedly measures the intensity of the scattered light obtained by incident on the dispersion liquid Lq. The conversion unit 54 obtains multiple scattered intensity data and converts these data into multiple scattered electric fields or time-varying characteristic data of the scattered intensity. Then, the particle size calculation unit 38b uses the multiple scattered electric fields or time-varying characteristic data of the scattered intensity to calculate the particle size d0, which is independent of the incident light intensity. This particle size d0, independent of the incident light intensity, is the measured particle size.

[0342] Like the optical measuring device 20 described above, the optical measuring device 20b also has a particle size distribution calculation unit 38c.

[0343] Furthermore, the processing unit 38 has a calculation unit 38d, which uses at least one of the scattering angle dependence data and the wavelength dependence data of the scattered light intensity related to known particles stored in the storage unit 55 to perform fitting for obtaining the particle size distribution of each of the various particle types.

[0344] The calculation unit 38d calculates the particle size distribution by fitting the theoretical formula relating a specified particle size to scattering intensity to multiple time-varying characteristic data of scattered electric fields or scattering intensities and multiple time-averaged scattered electric field data or time-averaged scattering intensity data obtained by the conversion unit 38a. The fitting based on the calculation unit 38d will be explained later.

[0345] The processing unit 38's arithmetic unit 38d can also read various data obtained by the conversion unit 54 and stored in the storage unit 55 to perform fitting. Furthermore, the processing unit 38 can also compare the scattering characteristics of particles stored in the model library with the particle size distribution value obtained from the measured fluctuation data and the wavelength dependence or intensity dependence of the measured scattered light, thereby determining the particle aggregation state or particle type.

[0346] Furthermore, the scattering characteristics of the particles can be, for example, scattering angle dependence data and wavelength dependence data of the scattered light intensity related to known particles. These particle scattering characteristics can be measured values ​​obtained using known particles such as standard particles, or calculated values ​​obtained using theoretical formulas that define the relationship between particle size and scattering intensity, such as the Mie scattering theory formula. Moreover, the particle scattering characteristics can also be calculated values ​​based on simulations. Simulation-based calculations can be obtained, for example, using the FDTD (Finite-difference time-domain method) or DDA (Discrete dipole approximation) method. The aforementioned particle scattering characteristics are stored, for example, as a model library in storage unit 55.

[0347] In the light measurement apparatus 20b, the reference light Lr can be blocked to prevent it from interfering with the scattered light. In this case, by cutting off the reference light Lr, normal dynamic light scattering measurement can be performed. As a method for cutting off the reference light Lr, for example, a retractable light shield is provided between the beam splitter 61a and the beam splitter 61c to prevent the light split from the beam splitter 61a from reaching the reflector 62.

[0348] Furthermore, a retractable light shield can be provided between beam splitter 61c and beam splitter 61d to block the reference light Lr reaching beam splitter 61d and thus cut off the reference light Lr.

[0349] In addition, if it can block light, it is not limited to a light shield that can move forward and backward; for example, an optical shutter that utilizes a liquid crystal shutter can be used.

[0350] With the above configuration, the light measurement device 20b can also be used as a dynamic light scattering device for general zero-difference detection.

[0351] In the light measurement apparatus 20b, the measurement unit 37 detects the intensity of the interference light for each incident light intensity. Thus, as described above, the scattering intensity of the scattered light obtained by repeatedly measuring the scattered light incident on the dispersion liquid Lq is obtained by the conversion unit 54, which obtains multiple scattering intensity data for each incident light intensity and converts the multiple scattering intensity data into multiple scattering electric field or time variation characteristic data of scattering intensity.

[0352] The particle size calculation unit 38b uses time-varying characteristic data of multiple scattering electric fields or scattering intensities to determine the measured particle size. That is, it determines the particle size d0, which is independent of the incident light intensity. The measured particle size is temporarily determined in the photometry apparatus 20b and is used when the particle size distribution is determined by the calculation unit 38d.

[0353] Furthermore, in the light measuring device 20b, for example, the intensity of interference light at each wavelength is detected.

[0354] The interference intensity spectra of three wavelengths, such as the center wavelengths of 620 nm, 640 nm, and 660 nm, are representatively extracted from the spectrum of the interference light obtained by the first detection unit 52a. Furthermore, the wavelength widths relative to the center wavelengths of 620 nm, 640 nm, and 660 nm are ±9 nm, respectively.

[0355] Next, the conversion unit 54 acquires data of signal components proportional to the electric field of scattered light at each wavelength at a specific depth from the interference light intensity detected by the first detection unit 52a. The scattering intensity data for each wavelength is converted into a power spectrum as time-varying characteristic data of the scattering intensity of scattered light at a specific depth of the dispersion Lq. Thus, the power spectrum is obtained. Furthermore, the conversion unit 54 performs an inverse Fourier transform on the power spectrum to obtain an autocorrelation function for each wavelength.

[0356] Next, in the processing unit 38, for example, the common logarithm (log) is taken for the autocorrelation function of each wavelength. 10 ), and calculate the slope Γg respectively. Use the slope Γg to calculate the diffusion coefficient D at each wavelength. The diffusion coefficient D is calculated from D = Γg / q. 2 This indicates that q is the scattering vector.

[0357] Here, as mentioned above, the diffusion coefficient D and particle size d are represented by the Stokes-Einstein formula (refer to equation (1)). In addition, the method of calculating the particle size distribution based on the slope of the autocorrelation function is not limited to this method. The CONTIN method, histogram method and cumulative expansion are known and can be used.

[0358] Next, in the processing unit 38, the hydrodynamic particle size of the particles at each wavelength is determined using the diffusion coefficient D for each wavelength. This hydrodynamic particle size is the aforementioned particle diameter d.

[0359] The aforementioned photometric devices 20, 20a, and 20b all utilize low-coherence dynamic light scattering (LC-DLS) to acquire time-varying characteristics of the scattered electric field, rather than time-varying characteristics of the scattered intensity. Furthermore, the scattering intensity and the scattering electric field have the relationship: Scattering Intensity = |Scattering Electric Field| 2 The relationship.

[0360] (The third example of a photometric method)

[0361] In the third example of the optical measurement method, multiple intensities of incident light are utilized in the optical measurement apparatus 20b. As described above, the scattering intensity of the scattered light obtained by repeatedly measuring the scattered light incident on the dispersion Lq is obtained by the conversion unit 54, and the multiple scattering intensity data are converted into multiple scattering electric fields or time-varying characteristic data of scattering intensity. The particle size calculation unit 38b uses the multiple scattering electric fields or time-varying characteristic data of scattering intensity to calculate the measured particle size.

[0362] Furthermore, in the third example of the optical measurement method, multiple wavelengths are utilized in the optical measurement apparatus 20b.

[0363] For example, a dispersion containing particles is measured using a supercontinuum light source. Through measurement, light of various wavelengths is detected in the photodetector 73 of the first detection unit 52a. The light of each wavelength incident on the photodetector 73 includes the interference light of scattered light and reference light, represented, for example, by an interference spectrum. The intensity I of the interference spectrum... k It is represented by the following formula. In the following formula, E S E is the electric field of the scattered light. S * For E S The complex conjugate quantity, E R For the reference electric field of light, E R * For E R The complex conjugate quantity.

[0364] I k =|E R +E S| 2 =|E R | 2 +|E S | 2 +E R E S * +E S E R *

[0365] Next, regarding the interference spectrum, for example, a wavelength region with a center wavelength of 620 nm is extracted (not shown). Furthermore, the width of this wavelength region is ±9 nm relative to the center wavelength of 620 nm. Thus, the scattering intensity of a specific wavelength region is extracted from the scattering intensity data for each wavelength. After extracting the scattering intensity of a specific wavelength region, the intensity I of the interference spectrum is calculated for that wavelength region. k Perform inverse Fourier transform F ‐1 Thus, for example, the depth-direction scattering distribution F of the dispersion Lq at the center wavelength of 620 nm can be obtained. ‐1 (I) K ).

[0366] The depth direction of the dispersion Lq is the optical axis of objective lens 65.

[0367] The inverse Fourier transform described above is represented by the following equation.

[0368]

[0369] In addition, r r Let denoted as reflectivity of reflector 62 relative to the electric field, E0 be the electric field of the light irradiating the sample, δ(z) be the delta function, ρ be the diffuse reflectivity of the scattered electric field at a depth s / 2 from the interface of the dispersion, and Γ be the reflectivity of the light irradiated by the reflector 62. ρ Let be the autocorrelation function of the diffuse reflectance of the scattered electric field relative to depth.

[0370] In the depth-direction distribution of the dispersion, for example, a single-scattering region is extracted as the depth region of interest. The single-scattering region, i.e., the region where light is scattered only once, is determined in the photometry apparatus 20b based on the optical path length. Preferably, the optical path length of the single-scattering region is predetermined in the photometry apparatus 20b. Furthermore, the aforementioned depth region of interest corresponds to a specific depth of the dispersion Lq.

[0371] The time response of the electric field in the depth of interest region is obtained by the first detection unit 52a. All time-series data of the signal obtained by the photodetector 73 are processed in the same way to obtain the time dependence of the signal quantity proportional to the scattered electric field E0ρ (s / 2) in the depth of interest region. A Fourier transform is performed on the time dependence of the scattered electric field, and a square operation is performed. Thus, the frequency response of the scattered light intensity, i.e., the power spectrum, can be obtained. Furthermore, the power spectrum I... ES It is represented by the following formula. Additionally, Γ of the following formula... ES Let be the autocorrelation function of the electric field.

[0372] [Formula 16]

[0373]

[0374] Next, the power spectrum I ES Perform an inverse Fourier transform. This yields the autocorrelation function of the scattered electric field. The inverse Fourier transform is expressed by the following equation.

[0375]

[0376] As described above, based on the extracted interference light intensity data, the power spectrum or autocorrelation function is obtained as the time-varying characteristic data of the scattered light intensity at a specific depth of the dispersion Lq. The conversion unit 54 performs the conversion of the scattered intensity data of each wavelength detected by the first detection unit 52a into the power spectrum or autocorrelation function of a specific depth of the dispersion Lq.

[0377] Next, in the particle size calculation unit 38b of the processing unit 38, the particle size is calculated using the time-varying characteristic data of the scattering intensity, i.e., the power spectrum or autocorrelation function, obtained by the conversion unit 54. The method for calculating the particle size using the autocorrelation function is as described above. The particle size of this particle is different from the particle size measured above.

[0378] Furthermore, the wavelength dependence of the time-averaged scattered electric field can be obtained as follows: after extracting the wavelength region, the time-averaged signal of the depth of interest region is calculated, and this is divided in the spectrum of the reference light by the intensity signal of the same wavelength region as described above. If this is further squared, the scattered light intensity normalized to the light source spectrum is obtained. As described above, for example, information on static light scattering by single scattering in a wavelength region with a center wavelength of 620 nm can be obtained.

[0379] For example, for a wavelength region with a center wavelength of 640 nm, or for a wavelength region with a center wavelength of 660 nm, information on static light scattering at each wavelength can be obtained by extracting the wavelength regions with a center wavelength of 640 nm and the wavelength region with a center wavelength of 660 nm from the interference spectrum. Furthermore, the width of the wavelength region is, for example, ±9 nm relative to the center wavelengths of 640 nm and 660 nm.

[0380] The average interparticle distance in bridging aggregates is greater than or equal to the diameter of a single particle. Data on single particles and bridging aggregates are stored as a model library in storage unit 55 (reference). Figure 9 In addition, bridging aggregates are, for example, composed of particles of a predetermined size and polymers present between the particles. As polymers, they are mostly those having functional groups (e.g., polar groups) that enable the particles to aggregate together.

[0381] In bridging condensates, scattering intensity decreases with increasing wavelength. On the other hand, in a single particle, scattering intensity increases with increasing wavelength.

[0382] In dynamic light scattering (DLS), only the hydrodynamic dimensions of the particles are known. Therefore, even if the particle size is known, it is impossible to determine whether it is a bridging aggregate or a single particle. In a single particle, the scattering intensity increases with increasing wavelength, thus it is possible to determine whether the particle is a single particle. Furthermore, the determination of a single particle is performed by the processing unit 38.

[0383] The above is in the order described below (for reference). Figure 10 By combining the wavelength dependence of dynamic and static light scattering with data from a model library, it is possible to determine not only the size of hydrodynamic particles but also the state and type of particles in the dispersion. The state of the particles in the dispersion may be, for example, a condensed state. The type and state of the particles in the dispersion are determined by the processing unit 38. Furthermore, the processing unit 38 only needs to be able to determine at least one of the type and state of the particles in the dispersion.

[0384] (Example 4 of photometric methods)

[0385] In the fourth example of the photometric method, the scattered light is the incident light obtained by changing the value of at least one of the measurement parameters, the scattering angle and the measurement wavelength.

[0386] It has a conversion process that converts the signals of multiple scattered light obtained through the measurement process into multiple time-averaged scattered electric field data or time-averaged scattered intensity data, and a calculation process that calculates the particle size or particle size distribution of various particle types based on the time-averaged scattered electric field data or time-averaged scattered intensity data and time variation characteristic data.

[0387] Furthermore, the measurement process includes the following steps: repeatedly measuring the scattering intensity of the scattered light obtained by changing the intensity of the incident light and then incident it into the dispersion, thereby obtaining multiple scattering intensity data; and repeatedly measuring the scattering intensity of the scattered light obtained by changing the value of at least one of the measurement parameters, namely the scattering angle and the measurement wavelength, thereby obtaining multiple scattering intensity data.

[0388] The conversion process is a process of calculating multiple time-varying characteristic data of scattering electric fields or scattering intensities based on multiple scattering intensity data obtained through the measurement process.

[0389] The following is a specific description of the fourth example of the photometric method, but the following description is only one example and is not particularly limited to the following description.

[0390] In the fourth example of the photometric method, the scattering angle, a parameter in the measurement parameters of scattering angle and measurement wavelength, is used to measure a dispersion containing multiple particle types, and the particle size or particle size distribution of each particle type is calculated. Furthermore, a supercontinuum light source is used, for example, as the light source.

[0391] In the light measurement apparatus 20b, the scattered light generated by irradiating a dispersion containing particles (not shown) with incident light of different wavelengths is detected by the first detection unit 52a through the photodetector 74 at each wavelength, and the data of the interference light intensity at each wavelength is obtained.

[0392] In the conversion unit 54, scattering intensity data at a specific scattering angle is obtained based on the data of interference light intensity. Then, the extracted scattering intensity data is converted into an autocorrelation function as time-varying characteristic data of the scattering intensity of scattered light at a specific depth of the dispersion.

[0393] The incident light intensity is varied and repeated multiple times to obtain multiple scattering intensity data for each incident light intensity (first measurement step). The multiple scattering intensity data obtained through the first measurement step are converted into multiple time-varying characteristic data of scattering electric field or scattering intensity (first conversion step).

[0394] In the first conversion step, for example, multiple autocorrelation functions are obtained for each incident light intensity.

[0395] Next, as described above, the measured particle size is determined using multiple autocorrelation functions for each incident light intensity (particle size calculation step). The measured particle size obtained in the particle size calculation step is a particle size independent of the incident light intensity. As described later, the particle size distribution is determined using the measured particle size (particle size distribution determination step).

[0396] Next, the scattered light is measured multiple times by changing at least one of the scattering angle and the measurement wavelength in the measurement parameters, thereby obtaining multiple scattering intensity data (second measurement step).

[0397] Then, the multiple scattering intensity data obtained through the second measurement step are converted into multiple scattering electric field or scattering intensity time variation characteristic data, and multiple time-averaged scattering electric field data or time-averaged scattering intensity data (second conversion step).

[0398] Next, the particle size distribution is determined by fitting the theoretical formula relating a specified particle size to scattering intensity with multiple time-varying characteristic data of scattered electric fields or scattering intensities obtained through the second conversion step and multiple time-averaged scattered electric field data or time-averaged scattering intensity data. This process is called the particle size distribution determination step. When determining the particle size distribution, the measured particle size obtained in the aforementioned particle size calculation step is used as the particle size in the theoretical formula relating the specified particle size to scattering intensity. Therefore, even particles with light-absorbing properties can have their particle size distribution obtained with high precision.

[0399] More specifically, in the light measurement device 20b, the first detection unit 52a detects the scattered light generated by irradiating the dispersion liquid Lq with multiple different incident lights at each wavelength through the photodetector 74 to obtain data on the intensity of the interference light.

[0400] In the conversion unit 54, scattering intensity data for each wavelength is obtained based on the scattering intensity data. Then, as described above, the extracted scattering intensity data is converted into an autocorrelation function as time-varying characteristic data of the scattering intensity of scattered light at a specific depth of the dispersion.

[0401] Next, the process of fitting the time-varying characteristic data of scattering intensity obtained by the conversion unit 54, and the time-averaged scattering electric field data or time-averaged scattering intensity data obtained by the conversion unit 54, to the theoretical formula relating a specified particle size to scattering intensity in the processing unit 38 will be explained. Through the above fitting, the particle size distribution of each of the various particle types contained in the dispersion is obtained. The following calculation formula can also be applied to the quantification or determination of particle types when there are two or more particle types contained in the dispersion. The method is shown below. In addition to using the theoretical formula relating a specified particle size to scattering intensity, the scattering characteristics of known particles can also be used in the fitting.

[0402] Here, Figure 10 This is a flowchart illustrating the fourth example of the light measurement method according to an embodiment of the present invention. Furthermore, in this fourth example of the light measurement method, in... Figure 10 Before the measurement process (step S10), the above-mentioned measurement particle size, which is independent of the incident light intensity, was determined.

[0403] like Figure 10 As shown, for example, the photometric method includes a measurement step (step S10), a step to obtain experimental data (step S12), a step to obtain pre-calculated values ​​(step S14), and an optimization step (step S16). Through the optimization step (step S16), the analysis results, namely the particle size distribution of each of the various particle types, are obtained (step S18).

[0404] The measurement process (step S10) includes, for example, measuring the temporal fluctuation of the interference light intensity and the scattering angle or wavelength dependence of the temporal average value of the interference light intensity. Step S10 is equivalent to the second measurement process.

[0405] The step of obtaining experimental data (step S12) obtains, for example, the time correlation of the interference light intensity with respect to time fluctuations based on the measured values ​​from the measurement step (step S10). Furthermore, it obtains the scattering angle dependence of the time-averaged interference light intensity or the wavelength dependence of the time-averaged interference light intensity. Step S12 corresponds to the second conversion step.

[0406] In the process of obtaining the pre-calculated value (step S14), the scattering characteristics of the particles are obtained using data such as the single particle and bridging condensation data stored in the storage unit 55 as a model library.

[0407] Furthermore, as mentioned above, the scattering characteristics of known particles can also be measured values ​​using standard particles. Alternatively, calculated values ​​obtained through theoretical formulas or simulations can be used as the scattering characteristics of particles. As mentioned above, the scattering characteristics of particles can be, for example, scattering angle dependence data and wavelength dependence data of the scattered light intensity related to known particles.

[0408] The scattering characteristics of the particles obtained in step S14 are used, for example, to determine the types of particles or multiple particle species in the dispersion. For instance, by comparing the measured values ​​obtained in step S10, such as particle size distribution values ​​obtained from measured fluctuation data and measured wavelength-dependent or intensity-dependent data of scattered light, with the scattering characteristics of the particles in step S14, the particle species and state of the particles in the dispersion are determined. The measured wavelength-dependent and intensity-dependent data of scattered light are obtained based on the time-varying characteristics of the scattered light intensity acquired by the conversion unit 54.

[0409] In the optimization process (step S16), for example, the theoretical formulas for the first-order autocorrelation function and scattering intensity are fitted with the time correlation of the time fluctuation of the interference light intensity and the time average value of the interference light intensity obtained in step S12. In step S16, after setting initial values ​​for the number of particles for all particle sizes, the final number of particles is obtained by updating the values ​​in a way that minimizes the evaluation value. The fitting process will be described in more detail below.

[0410] (The first example of fitting)

[0411] The following example illustrates the situation where a dispersion contains two types of particles, A and B.

[0412] Furthermore, this is based on the premise that the particle types of particles A and B, and the wavelength dependence of the complex refractive index of particles at various particle sizes, are known. In this case, wavelength dependence data of the scattered light intensity, calculated based on the known complex refractive index, particle size, and shape of the particles, exists and is stored as a model library in storage unit 55 (see reference). Figure 9 )middle.

[0413] First-order autocorrelation function express.

[0414] When there are two types of particles, A and B, in the dispersion, the first-order autocorrelation function is represented by the following equation (19).

[0415] Furthermore, the scattering intensity is expressed by the following equation (20). Equations (19) and (20) are theoretical formulas, and Is of equations (19) and (20) total All values ​​are calculated. Furthermore, I d´ A and I d´ B These are theoretical values, and the pre-calculated values ​​obtained in step S14 above can be used.

[0416] Furthermore, in the following equations (19) and (20), g （1） This represents the first-order autocorrelation function. totalThis represents the total scattering intensity. d´ and d0 represent the particle size. The subscripts 0 to M of d´ and d0 indicate... Figure 11 , Figure 12 The histogram shown is represented by the ordinal number of the segment. N represents the number of particles. The subscripts of N from 0 to M indicate... Figure 11 , Figure 12 The histogram segments shown are their ordinal numbers. Furthermore, a histogram segment refers to a data range within the histogram, represented by bars.

[0417] Furthermore, D represents the diffusion coefficient. The subscript d´ of the diffusion coefficient D indicates that it depends on the particle size d´. q represents the scattering vector. τ represents the time delay of the first-order autocorrelation function. θ represents the scattering angle. Is represents the scattering intensity. The subscript d of the scattering intensity Is indicates that it depends on the particle size d.

[0418] In equations (19) and (20) below, the superscripts A and B indicate that the wavelength dependence of the scattering intensity corresponds to particle A and particle B.

[0419] [Formula 17]

[0420]

[0421] In the above equation (19), the following term corresponds to particle A and is related to... Figure 11 The histogram of particle A is shown below. In the following terms, exp(-Dqτ) is the first-order autocorrelation function, and N is the only other term. d´ A Is d´ A / Is total The part represents the ratio of the scattering intensity of all particles A belonging to the segment with particle size d´ to the total reflection intensity. This is the weight of particle A. Furthermore, Is in equation (19) total This is a theoretical value determined based on the particle size. As a theoretical value, the Mie scattering theory formula can be used. Equation (19) shows Is... total This is equivalent to parameter-dependent data of scattering intensity, or time-averaged scattering electric field data or time-averaged scattering intensity data.

[0422] [Formula 18]

[0423]

[0424] In the above equation (19), the following term corresponds to particle B, and is related to... Figure 12 The histogram of particle B is shown below. In the following terms, exp(-Dqτ) is the first-order autocorrelation function, and N... d´ B Is d´ B / Is totalThe part represents the ratio of the scattering intensity of all particles B belonging to the segment with particle size d´ to the total reflection intensity. This is the weight of particle B.

[0425] [Formula 19]

[0426]

[0427] [Formula 20]

[0428]

[0429] In the above equation (20), N d0 A Is d0 A Corresponding to the scattering intensity of particle A, N d0 B Is d0 B Corresponds to the scattering intensity of particle B.

[0430] The following explains the fitting process for determining the particle size distribution of various particle types. In the fitting, particle size is used as the fitting parameter, and the number of particles is used as the variable, ultimately determining the number of particles for each particle size.

[0431] The first-order autocorrelation function g was measured for each wavelength. （1） (τ) has multiple first-order autocorrelation functions g （1） (τ). As a measured value, for example, it is the autocorrelation function of the above-mentioned multiple wavelengths.

[0432] In the fitting process, for the first-order autocorrelation function of each wavelength, the initial particle number is set as a variable in equation (19). The calculated value of the first-order autocorrelation function of equation (19) based on the set initial particle number is obtained. The first-order autocorrelation function of each wavelength is equivalent to the time variation characteristic data of the scattering intensity derived from the scattering characteristics using the theoretical formula.

[0433] For each wavelength, the difference between the measured value of the first-order autocorrelation function and the calculated value of the first-order autocorrelation function in equation (19) is obtained. Furthermore, the difference between the measured value of the first-order autocorrelation function and the calculated value of the first-order autocorrelation function in equation (19) is called the difference of the first-order autocorrelation function. The difference of the first-order autocorrelation function is obtained for each wavelength.

[0434] For example, the total scattering intensity Is was measured at each wavelength. total Additionally, it is also possible to determine the total scattering intensity Is. total This is used to determine that the particle is not a condensate but a single particle.

[0435] In equation (20), the number of particles is set as a variable. The total scattering intensity Is is obtained based on the set initial number of particles in equation (20). total The value of .

[0436] Calculate the measured total scattering intensity Is for each wavelength. total The value of the total scattering intensity Is in equation (20) total The difference between the calculated values. Additionally, the measured total scattering intensity Is at any wavelength. total The value of the total scattering intensity Is in equation (20) total The difference between the calculated values ​​is called the total scattering intensity Is at wavelength. total The difference. Regarding the total scattering intensity Is total The total scattering intensity Is at the wavelength can be obtained. total The difference. The total scattering intensity Is of equation (20) total The calculated value is equivalent to the time-averaged data of the time-varying characteristics of scattering intensity.

[0437] In the fitting process, to determine the final particle count, the difference between the first-order autocorrelation functions obtained for each wavelength and the difference between the total scattering intensities at that wavelength are used. For example, an evaluation value is obtained by adding the squares of the differences between the first-order autocorrelation functions obtained for each wavelength and the squares of the differences between the total scattering intensities at that wavelength for all wavelengths. The particle count that minimizes this evaluation value is taken as the final particle count.

[0438] Therefore, in the fitting process, the particle count is repeatedly updated in equations (19) and (20) in a way that minimizes the evaluation value to obtain the final particle count. This is equivalent to step S16 above.

[0439] After setting initial values ​​for the number of particles for all particle sizes, the count is updated in a way that minimizes the evaluation value. The final number of particles is obtained for each particle size, for example, by obtaining... Figure 11 The histogram of particle A shown and Figure 12 The histogram of particle B is shown. That is, by applying the histogram to all d´=d0~d M Find N d´ A N d´ B This allows us to obtain the particle size distribution. This is equivalent to step S18 above. Particle size distribution refers to the distribution of the number of particles relative to the particle size, expressed as a percentage (%).

[0440] The above steps are for determining the particle size distribution of various particle types. Furthermore, the evaluation values ​​used for fitting are not limited to those described above.

[0441] Furthermore, the first-order autocorrelation function of equation (19) is a value obtained through measurement. As mentioned above, when the particles have the property of absorbing light, the particle size changes according to the intensity of the incident light. On the other hand, equation (20) is a theoretical value, and the particle size of equation (20) is the particle size that is not affected by the intensity of the incident light. Therefore, the particle size of equation (19) is inconsistent with the particle size of equation (20). Using the pre-determined measured particle size, i.e., the particle size d0 that is independent of the intensity of the incident light, the particle size d´ of the autocorrelation function of equation (19) is set to a state in which the particle size of equation (19) is consistent with the particle size of equation (20). In this state, the particle size is used as a fitting parameter, the number of particles is used as a variable, and multiple time-varying characteristic data of scattering electric fields or scattering intensities, and multiple time-averaged scattering electric field data or time-averaged scattering intensity data are fitted to the theoretical formula of the relationship between the specified particle size and scattering intensity to obtain the particle size distribution. Thus, the particle size distribution of the particles contained in a dispersion containing particles with the property of absorbing light can be measured with high precision.

[0442] Furthermore, in the optical measuring apparatus 20b, the type of particles in the dispersion can be determined by utilizing the difference in scattering intensity relative to wavelength. Therefore, by pre-determining the relationship between the type of particles and the scattering intensity relative to wavelength, the type of particles and the particle size distribution can also be determined. Preferably, the relationship between the type of particles and the interference light intensity relative to wavelength is stored in the storage unit 55 beforehand. In the processing unit 38, the relationship between the type of particles and the interference light intensity relative to wavelength is read from the storage unit 55, and the type of particles and the particle size distribution can also be determined.

[0443] As mentioned above, the two theoretical formulas, namely equations (19) and (20), are combined with the measured first-order autocorrelation function and the measured total scattering intensity Is. total The final number of particles is determined by fitting the data. However, the optimization method for fitting is not limited to the above; for example, Bayesian optimization can be used in fitting.

[0444] In addition, when calculating the number of particles as described above, a first-order autocorrelation function was used, but it is not limited to this. The power spectrum can also be used instead of the first-order autocorrelation function.

[0445] Furthermore, as described above, by fitting the theoretical formula to the autocorrelation function or power spectrum of the scattering intensity and the scattering intensity at each wavelength, it is possible to obtain the particle number and particle size distribution for each particle type, such as particle A and particle B. Moreover, when impurities are present in the dispersion, the particle size distribution of the impurities and each particle type can be obtained, thus separating the influence of the impurities. In addition to the theoretical formula, the fitting can also utilize time-varying characteristic data of scattering intensity derived from the known scattering characteristics of the particles, as well as time-averaged scattering electric field data or time-averaged scattering intensity data.

[0446] In addition, two examples were given regarding wavelength, but the wavelength is not limited to two. As long as there are multiple wavelengths, there can be three or four wavelengths.

[0447] Furthermore, the method described above, which calculates the particle size distribution of various particle types based on time-averaged scattered electric field data, time-averaged scattered intensity data, and time-varying characteristic data through fitting, is not limited to this. For example, it is also possible to calculate the particle size of various particle types based on time-averaged scattered electric field data, time-averaged scattered intensity data, and time-varying characteristic data. In this case, for example, the average particle size of each particle is calculated based on the particle size distribution of each particle type. This average particle size of each particle type is taken as the particle size of each particle. The average particle size of each particle type is calculated by the particle size calculation unit 38b.

[0448] It is also possible to determine the complex refractive index. Regarding the complex refractive index, as mentioned above, the real part is called the so-called refractive index. The imaginary part of the complex refractive index is called the extinction coefficient, which represents absorption.

[0449] Transformer 54 (Reference) Figure 9 It can also convert multiple scattering intensity data obtained by the first detection unit 52a into time-varying scattering intensity data, time-averaged scattering electric field data, or time-averaged scattering intensity data. Using theoretical formulas or simulations based on the relationship between specified refractive index, particle size, and scattering intensity, it fits the acquired time-varying scattering intensity data, time-averaged scattering electric field data, or time-averaged scattering intensity data. Through fitting, it determines the combination of particle types, particle refractive index, and particle size distribution in the dispersion, and identifies the material composition of each particle type in the determined dispersion. The fitting process will be described later.

[0450] In this case, similar to the aforementioned photometric apparatus 20, the intensity of the incident light from the light source 22 is varied, and the scattered light incident on the dispersion Lq is measured multiple times to obtain multiple scattering intensity data. These multiple scattering intensity data are then converted into multiple scattering electric fields or time-varying characteristic data of scattering intensity. The measured particle size is then determined using these multiple scattering electric fields or time-varying characteristic data of scattering intensity. The measured particle size is temporarily determined and used when determining the particle size distribution.

[0451] In addition to the theoretical formula that specifies the relationship between particle size and scattering intensity, time-varying characteristic data of scattering intensity of the measurement parameters, calculated by simulation based on electromagnetic wave behavior theory, and time-averaged scattering electric field data or time-averaged scattering intensity data of the measurement parameters can also be used.

[0452] In addition, in the processing unit 38, the time variation characteristics data of the scattering intensity of the measured parameters calculated above are calculated as described above.

[0453] When measuring the scattered light of a dispersion, the scattering angle is used as a measurement parameter. When the measurement parameter is the scattering angle, the scattered light of the dispersion is measured by changing the value of the scattering angle by two or more angles. In this case, for example, the measurement wavelength is fixed at one wavelength.

[0454] When the measurement parameter is the measurement wavelength of the measurement light, two or more measurement wavelengths are used to measure the scattered light of the dispersion. In this case, for example, the scattering angle is fixed at one. The two wavelengths are the values ​​of the measurement parameter.

[0455] As measurement parameters, there are also cases where the scattering angle and the measurement wavelength are used. In this case, the scattering angle is set to two or more angles and the measurement wavelength is set to two or more wavelengths, and the scattered light of the dispersion is measured by the combination of each scattering angle and measurement wavelength.

[0456] The value of the scattering angle is not particularly limited as long as it is two or more angles, and can be appropriately determined from the number of scattering intensity data and the measurement time, etc. The preferred value of the scattering angle is greater than 0° and 180°.

[0457] Furthermore, there are no particular limitations as long as the measured wavelength is two or more. The appropriate determination can be made by considering factors such as the need for a larger light source or optical elements that can be used to divide the wavelengths.

[0458] Furthermore, the measurement wavelength is not particularly limited, and various wavelengths of light, such as ultraviolet, visible, and infrared light, can be appropriately utilized.

[0459] Furthermore, as mentioned above, the scattering intensity can be measured by light scattering measurement or by a single measuring device in combination with an apparatus. Alternatively, it can be measured using a dynamic light scattering measuring device, a light scattering goniometer, or a combination of measurement data from two different devices. In the case of wavelength, a spectrometer can also be used. As mentioned above, the apparatus is not limited to, for example, the use of... Figure 9 The light measuring device 20b shown is an example.

[0460] The dispersion contains at least one type of particle, or multiple types of particles. That is, assuming there are multiple types of particles in the dispersion, a theoretical formula is established to define the relationship between refractive index, particle size, and scattering intensity to determine the material of each type of particle.

[0461] (5th example of optical measurement methods)

[0462] Figure 13This is a flowchart illustrating the fifth example of the light measurement method according to an embodiment of the present invention.

[0463] In addition, in the fifth example of the photometry method, in Figure 13 Before the measurement process (step S20), the above-mentioned particle size was determined.

[0464] In the fifth example of the photometric method, the measurement parameter is the scattering angle. The intensity of the scattered light from the dispersion is measured while the value of the scattering angle is changed by more than two angles.

[0465] like Figure 13 As shown, the fifth example of the optical measurement method includes, for example, a measurement step (step S20), a step of obtaining experimental data (step S22), a step of obtaining pre-calculated values ​​(step S24), an optimization step (step S26), a step of obtaining the optimization result (step S28), a step of performing refractive index matching (step S30), and a step of obtaining analytical results (step S32). Furthermore, it includes a library preparation step (step S34). Through the step of obtaining analytical results (step S32), the material of each particle type contained in the dispersion can be determined.

[0466] Furthermore, a library refers to a material with a corresponding refractive index. The refractive index of the library is a measured value or a value recorded in literature, etc. Moreover, the refractive index can be a complex refractive index. For example, the library is stored in storage unit 55.

[0467] Furthermore, in the processing unit 38, the refractive index matching of the materials in the library is performed. The processing unit 38 also calculates the pre-calculated value (described later) and performs a series of processes for calculating the pre-calculated value.

[0468] In the measurement process (step S20), at least one of the scattering angle and the measurement wavelength is set as a measurement parameter, and the scattering intensity of the scattered light emitted from the dispersion is measured multiple times by changing the values ​​of multiple set measurement parameters. In the measurement process (step S20), for example, the time fluctuation of the scattering intensity and the scattering angle dependence of the time average value of the scattering intensity are measured.

[0469] In the step of obtaining experimental data (step S22), the autocorrelation function of the scattering intensity relative to time fluctuation is obtained, for example, based on the measured values ​​from the measurement step (step S20). Furthermore, the time-averaged scattering intensity, which is dependent on the scattering angle or wavelength, is obtained. Thus, for example, it is possible to obtain... Figure 14 The scattering intensity is shown for each scattering angle.

[0470] Here, Figure 14This is a graph representing the calculated scattering angle and scattering intensity for each refractive index of particles of the same size, showing the distribution of scattering intensity obtained through calculation. Figure 14 In the diagram, symbol 80 represents the distribution showing the relationship between the scattering angle and the refractive index 1.48. Symbol 81 represents the distribution showing the relationship between the scattering angle and the refractive index 1.59. Symbol 82 represents the distribution showing the relationship between the scattering angle and the refractive index 2.2. (The text repeats itself here.) Figure 14 As shown, even for particles of the same size, different refractive indices will result in different distributions of scattering intensity relative to the scattering angle.

[0471] In the step of obtaining the pre-calculated value (step S24), the calculated value of the scattering intensity is obtained, for example, using a theoretical formula based on the relationship between a specified refractive index, particle size, and scattering intensity, or a simulation based on electromagnetic wave behavior theory. Furthermore, time-varying characteristic data of the scattering intensity of the measurement parameter calculated using the theoretical formula based on the relationship between the specified refractive index, particle size, and scattering intensity, and time-averaged scattering electric field data or time-averaged scattering intensity data of the measurement parameter are obtained. Alternatively, time-varying characteristic data of the scattering intensity of the measurement parameter calculated using a simulation based on electromagnetic wave behavior theory, and time-averaged scattering electric field data or time-averaged scattering intensity data of the measurement parameter are obtained.

[0472] The calculation method for the time-averaged scattered electric field data or time-averaged scattered intensity data in step S24 is the same as the calculation method for the multiple time-averaged scattered electric field data or time-averaged scattered intensity data in the conversion unit 54 described above, so its detailed description is omitted.

[0473] Furthermore, in step S24, the measured value of the scattering intensity using known particles such as standard particles can also be obtained. Additionally, the pre-calculated values ​​obtained in step S24 are used to determine the number of particle types, the refractive index of each particle type, and the number of particles, as described later.

[0474] In the optimization process (step S26), for example, the theoretical formulas for the autocorrelation function and scattering intensity are fitted with the autocorrelation function of the time fluctuation of the scattering intensity and the time average value of the scattering intensity obtained in step S22. In step S26, after setting initial values ​​for the number of particle types, the refractive index of each particle type, and the number of particles contained in the dispersion, the values ​​are updated in a way that minimizes the evaluation value to determine the final combination of the number of particle types, the refractive index of each particle type, and the number of particles. Furthermore, the initial values ​​are set by generating random variables.

[0475] Next, after obtaining the optimization result (step S28), the refractive index of each particle type in the dispersion, which is determined by fitting the combination of the number of various particle types, the refractive index of the particles, and the particle size distribution, is matched with the refractive index of the materials in the library (step S30). Thus, the material of each particle type in the dispersion is determined, and the material of each particle type in the dispersion is obtained as an analysis result (step S32). Furthermore, in the refractive index matching (step S30), for example, the refractive index that minimizes the square of the refractive index difference is selected. And, the refractive indices of the materials are prepared in advance in the form of a library (step S34).

[0476] The light scattering measurement method will be described in more detail below, including fitting.

[0477] First, from Figure 9 The light source 22 of the light measuring device 20b shown is, for example, a laser beam of a specific wavelength incident on the dispersion Lq. The second detection unit 52b detects the scattered light scattered by the incident light at different scattering angles. Thus, the signal (scattering intensity) of the scattered light of the dispersion Lq at different scattering angles can be obtained. The scattering angle value is two or more angles. The above process is a measurement process, equivalent to step S20 described above (refer to...). Figure 13 ).

[0478] Next, the conversion unit 54 calculates the time-dependent scattering intensity of the dispersion Lq obtained through the measurement process as time-varying characteristic data of the scattering intensity, for example, using a known method to calculate the autocorrelation function or power spectrum. In this way, time-varying characteristic data of the scattering intensity is obtained for each scattering angle. Multiple time-varying characteristic data can be obtained.

[0479] Next, in the conversion unit 54, time-averaged scattered electric field data or time-averaged scattered intensity data is obtained from the signal of the scattered light of the dispersion obtained through the measurement process.

[0480] Time-averaged scattering electric field data or time-averaged scattering intensity data of a dispersion can be obtained, for example, by calculating the time average of the scattering intensity based on the signal of the scattered light from the dispersion at each scattering angle. Thus, data such as... Figure 14 The data shown is the scattering intensity data for each scattering angle.

[0481] The process of obtaining the time variation characteristics data of the scattering intensity of the above dispersion and the time average scattering electric field data or time average scattering intensity data of the dispersion is the second conversion process, which is equivalent to the above step S22.

[0482] Next, in processing unit 38, theoretical formulas or simulations based on the relationship between specified refractive index, particle size, and scattering intensity are used to fit the time-varying characteristic data of scattering intensity at two or more scattering angles, as well as multiple time-averaged scattering electric field data or time-averaged scattering intensity data. The combination of the number of various particle types, the refractive index of the particles, and the particle size distribution in the dispersion is determined through this fitting. This is equivalent to steps S26 and S28 described above.

[0483] As described above, the dispersion contains at least one particle.

[0484] Furthermore, as mentioned above, the first-order autocorrelation function is derived from... In addition, the relationship between the diffusion coefficient and the particle size obtained from the autocorrelation function is applicable to the Stokes-Einstein formula commonly used in dynamic light scattering methods (refer to equation (1)).

[0485] When the particles have a particle size distribution, the first-order autocorrelation function is represented by equation (21) below. Furthermore, the scattering intensity is represented by equation (22) below. Equations (21) and (22) below are theoretical formulas. The I of equations (21) and (22) θ total These are calculated values, equivalent to time-averaged scattered electric field data or time-averaged scattered intensity data.

[0486] Furthermore, the first-order autocorrelation function of equation (21) is a value obtained through measurement. As mentioned above, when the particles have the property of absorbing light, the particle size changes according to the intensity of the incident light. On the other hand, equation (22) is a theoretical value, and the particle size of equation (22) is the particle size that is not affected by the intensity of the incident light. Therefore, the particle size of equation (21) is inconsistent with the particle size of equation (22). Therefore, using the measured particle size d0 that is not dependent on the intensity of the incident light obtained above, we set it to a state in which the particle size of equation (21) is consistent with the particle size of equation (22). In this state, the particle size is used as a fitting parameter, and the number of particles is used as a variable. As mentioned above, multiple time-varying characteristic data of scattering electric field or scattering intensity, and multiple time-averaged scattering electric field data or time-averaged scattering intensity data are fitted to the theoretical formula of the relationship between the specified particle size and scattering intensity to obtain the particle size distribution and relative complex refractive index m.

[0487] [Formula 21]

[0488]

[0489] [Formula 22]

[0490]

[0491] In addition, in equation (21), g （1）Let represent the first-order autocorrelation function. The first-order autocorrelation function of Equation (21) is the first-order autocorrelation function for each scattering angle. The scattering intensity of Equation (22) is the scattering intensity for each scattering angle. Therefore, Equations (21) and (22) are obtained for each scattering angle to be measured.

[0492] In equations (21) and (22), Is θ total The total scattering intensity is represented by d´ and d0. The subscripts 0 to M of d´ and d0 indicate the ordinal numbers of the segments in the histogram of the particles. N represents the number of particles. D represents the diffusion coefficient. The subscript d´ of the diffusion coefficient D indicates that it depends on the particle size d´. q represents the scattering vector. τ represents the time delay of the first-order autocorrelation function. θ represents the scattering angle. Is represents the scattering intensity. The subscript d´ of the scattering intensity Is indicates that it depends on the particle size d´. The subscript θ of the scattering intensity Is indicates that it depends on the scattering angle θ. Additionally, the segments in the histogram refer to the data intervals of the histogram, represented by bars in the histogram.

[0493] N d´ Is d´,θ / Is θ total The part represents the ratio of the scattering intensity of all individual particles belonging to the segment with particle size d´ to the total scattering intensity.

[0494] The scattering intensity of particles with a diameter d´ and a relative complex refractive index m is given by the Mie scattering theory using the following formula. The following formula is a theoretical formula that specifies the relationship between refractive index, particle size, and scattering intensity.

[0495] [Formula 23]

[0496]

[0497] Here, P l This represents the function obtained by partially differentiating Legendre's polynomial with respect to θ, where the subscript l indicates the order of Legendre's polynomial. λ represents the wavelength in the solvent. d is the particle size, r is the distance from the particle, and m is the relative complex refractive index of the particle with respect to the medium. Furthermore, when the refractive index of the solvent is set to n0 and the refractive index of the particle is set to n, m = n / n0. Moreover, the coefficient A... l (m, d') and B l (m, d') are given by the following formula. In the following formula, the '' added to ψ and ζ is the differential related to the factors in each function, and its meaning is different from that of the '' added to d.

[0498] [Formula 24]

[0499]

[0500] [Formula 25]

[0501]

[0502] Furthermore, x is defined as follows. And ψ1(ρ) and ζ1(ρ) are represented by the following formulas, where J is the Bessel function and ζ is the Hankel function.

[0503] [Formula 26]

[0504]

[0505] [Formula 27]

[0506]

[0507] [Formula 28]

[0508]

[0509] When the number of particle types is 2, the number of terms becomes two, and the above equations (21) and (22) become the following equations (23) and (24). The same applies when the number of particle types is 3 or more.

[0510] [Formula 29]

[0511]

[0512] [Formula 30]

[0513]

[0514] (The second example of fitting)

[0515] The following describes the fitting of the particle species used to determine the number of particle species contained in the dispersion and the material for each particle species.

[0516] The second-order autocorrelation function g was measured at each scattering angle. （2） (τ) is preferably two or more angles, but can also be a single angle. The number of measured scattering angles is appropriately determined based on the number of variables obtained, or the number of time-averaged scattering electric field data or time-averaged scattering intensity data of the measured parameters.

[0517] In the fitting process, the first-order autocorrelation function for each scattering angle is defined in equations (21) and (23), or in the same equations for particle types 3 and above, with the number of particle types, the refractive index of each particle type, and the number of particles as variables to set the initial number of particles. The calculated value of the first-order autocorrelation function of equation (21) based on the set initial number of particles is obtained. The second-order autocorrelation function is then obtained based on the calculated value of the first-order autocorrelation function. The calculated value is given. Additionally, βg is a device constant.

[0518] For each scattering angle, the difference between the measured value and the calculated value of the second-order autocorrelation function is calculated. This difference is called the second-order autocorrelation function difference. The calculated value of the second-order autocorrelation function at each scattering angle corresponds to the time-varying characteristic data of the scattering intensity of the measured parameter calculated using theoretical formulas.

[0519] The total scattering intensity Is measured at each scattering angle total In equations (22), (24), or the same equations for particle types 3 and above, calculate the total scattering intensity Is based on the set initial values ​​in equations (22), (24), or the same equations for particle types 3 and above. θ total The value of .

[0520] Calculate based on each scattering angle, as follows: Figure 14 The measured total scattering intensity Is shown total The value of the total scattering intensity I is the same as that in equations (22), (24) or for particle types 3 or above. θ total The difference between the calculated values. Additionally, the measured total scattering intensity Is at any scattering angle. total The value of the total scattering intensity I is the same as that in equations (22), (24) or for particle types 3 or above. θ total The difference between the calculated values ​​is called the total scattering intensity Is at the scattering angle. total The difference. Regarding the total scattering intensity Is total The total scattering intensity Is at the scattering angle can be obtained. total The difference. The total scattering intensity I in equations (22) and (24) is... θ total The calculated value is equivalent to the time-averaged scattering electric field data or time-averaged scattering intensity data of the measured parameters calculated through theoretical formulas.

[0521] In the fitting process, to determine the final number of particle species, the refractive index of each particle species, and the number of particles, the difference between the second-order autocorrelation functions obtained for each scattering angle and the difference between the total scattering intensity at that scattering angle are used. For example, an evaluation value is obtained by adding the square of the difference between the second-order autocorrelation functions obtained for each scattering angle and the square of the difference between the total scattering intensity at that scattering angle for all scattering angles. The evaluation value is then used as the minimum combination of the number of particle species, the refractive index of each particle species, and the number of particles to determine the final particle species. Since the particle species and the number of particles are available, the particle size distribution for each particle species can be obtained.

[0522] In the fitting process, to minimize the evaluation value, the number of particle types, the relative complex refractive index m of each particle type, and the number of particles are repeatedly updated in equations (23) and (24) corresponding to the number of particle types to obtain the final number of particles and the relative complex refractive index m. This is equivalent to step S26 above. In the fitting process, when repeatedly updating the number of particle types, the relative complex refractive index m of each particle type, and the number of particles in a way that minimizes the evaluation value, a genetic algorithm is used, for example, to update the number of particle types, the relative complex refractive index m of each particle type, and the number of particles. As a result, the number of particle types, the relative complex refractive index m of each particle type, and the number of particles can be updated more reliably.

[0523] In the fitting process, the formula representing the relative complex refractive index m is updated in the formulas (23) and (24) corresponding to the number of particle species, as described above, to fit the measured values ​​with the calculated values, thereby obtaining the final number of particles and the relative complex refractive index m. The refractive index is fitted by the formula representing the relative complex refractive index m.

[0524] By obtaining the number of particles for all particle types and sizes, a particle histogram can be obtained. That is, within the particles, by obtaining the number of particles for all d´=d0~d... M Obtain N d´ A ..., capable of obtaining particle size distribution for all particle types.

[0525] The above steps are steps for determining the combination of the number of particle types, the relative complex refractive index m of each particle type, and the particle size distribution (step S28). Furthermore, the evaluation values ​​used for fitting are not limited to those described above.

[0526] The refractive index of each particle type is matched with the refractive index of the material in the library (step S30), and the material of each particle type is obtained as the analysis result (step S32). In the matching, for example, the refractive index that minimizes the square of the difference between the refractive index of the obtained particle and the refractive index of the material in the library is selected.

[0527] The above steps are for determining the material for each particle type of unknown particles contained in the dispersion. Furthermore, the evaluation values ​​used for fitting are not limited to those described above.

[0528] Furthermore, the first-order autocorrelation function of equation (23) is a value obtained through measurement. As mentioned above, when the particles have the property of absorbing light, the particle size changes according to the intensity of the incident light. On the other hand, equation (24) is a theoretical value, and the particle size of equation (24) is the particle size that is not affected by the intensity of the incident light. Therefore, the particle size of equation (23) is inconsistent with the particle size of equation (24). Therefore, in equations (23) and (24), the measured particle size d0, which is independent of the intensity of the incident light, is also used as described above, and is set to a state in which the particle size of equation (23) is consistent with the particle size of equation (24). In this state, the particle size is used as a fitting parameter, the number of particles is used as a variable, and the theoretical formula for the relationship between the specified particle size and the scattering intensity is fitted to obtain the particle size distribution and the relative complex refractive index m.

[0529] In addition to the scattering angle, results measured at different wavelengths can be added to determine the wavelength dependence of the refractive index. That is, multiple measurement wavelengths (two or more) can be used to measure the intensity of the scattered light to obtain multiple scattered light data, thereby determining the combination of particle species, refractive index of each particle species, and particle size distribution. In this case, the scattering angle can be a single angle, or multiple angles (two or more).

[0530] By changing the measurement wavelength, the wavelength dependence of the refractive index can be obtained. This wavelength dependence of the refractive index is also called refractive index dispersion. When changing the measurement wavelength used as a measurement parameter, if there are multiple measurement wavelengths, it is not limited to two; it can also be three or four.

[0531] Here, in Figure 15 and Figure 16 The diagram shows the relationship between scattering intensity and the measurement wavelength. Figure 15 The diagram shows the scattering intensity calculated at a measurement wavelength of 488 nm for two particles with different refractive indices. Figure 15 As shown, the distribution 84 of the scattering intensity of the first particle is different from the distribution 85 of the scattering intensity of the second particle.

[0532] Figure 16 The diagram shows the calculated scattering intensity for two particles at a measurement wavelength of 632.8 nm. (Example:) Figure 16 As shown, the scattering intensity distribution 86 of the first particle is different from the scattering intensity distribution 87 of the second particle. (As...) Figure 15 and Figure 16As shown, the scattering intensity varies with the wavelength of measurement depending on the difference in refractive index. This can be used to determine the type of particle.

[0533] For example, time-averaged scattering electric field data or time-averaged scattering intensity data of a dispersion are obtained by calculating the time average of the scattering intensity of the dispersion for each laser beam wavelength.

[0534] Furthermore, the optimization methods for fitting are not limited to those mentioned above; for example, Bayesian optimization can be used in fitting.

[0535] Furthermore, as mentioned above, a second-order autocorrelation function was used to determine the number of particle species, the refractive index of each particle species, and the number of particles in the dispersion. However, this is not a limitation; the power spectrum can also be used instead. Moreover, the first-order autocorrelation function can also be used when measuring the first-order autocorrelation function using heterodyne detection.

[0536] In addition to theoretical formulas, fitting can also use time-varying characteristic data of scattering intensity of the measured parameters calculated through simulation, as well as time-averaged scattering electric field data or time-averaged scattering intensity data of the measured parameters.

[0537] (The 6th example of a photometric method)

[0538] Figure 17 This is a flowchart illustrating the sixth example of the light measurement method according to an embodiment of the present invention.

[0539] In the sixth example of the photometric method, regarding the relationship with Figure 13 The fifth example of the light measurement method shown follows the same procedure, and its detailed description is omitted.

[0540] The sixth example of the optical measurement method differs from the fifth example in that the evaluation optimization and the use of the refractive index of the library in the pre-calculated value are the same as the fifth example of the optical measurement method.

[0541] In addition, in the sixth example of the photometry method, in Figure 10 Before the measurement process (step S10), the above-mentioned particle size was determined.

[0542] In the sixth example of the photometric method, similar to the fifth example, it includes a measurement step (step S40), a step for obtaining experimental data (step S42), an optimization step (step S44), a step for obtaining the optimization result (step S46), and a step for obtaining the analytical result (step S48). Furthermore, it includes a library preparation step (step S50), a step for using the library to identify the number of particle types and candidates for each particle type (step S52), and a step for obtaining a pre-calculated value (step S54). Through the step of obtaining the analytical result (step S48), the material of each particle type contained in the dispersion can be determined.

[0543] Furthermore, the measurement procedure (step S40), the experimental data acquisition procedure (step S42), and the optimization procedure (step S44) are the same as the measurement procedure (step S20), the experimental data acquisition procedure (step S22), and the optimization procedure (step S26) in the fifth example of the photometry method, so their detailed descriptions are omitted.

[0544] In the sixth example of the photometric method, the number of particle species and candidates for each particle species are selected using the prepared library (step S50) (step S52). Pre-calculated values ​​are obtained based on the selected number of particle species and candidates for each particle species (step S54).

[0545] In steps S50, S52, and S54, a quantity of refractive index data of candidate materials equivalent to the number of candidate particle types is retrieved from the library as initial values ​​(step S50). Furthermore, initial values ​​for the particle size distribution of the candidate particle types are prepared (step S52). The scattering intensity and second-order autocorrelation function are calculated using the refractive index data and the initial values ​​for the particle size distribution of the candidate particle types (step S54). The number of particle types and the candidate materials for each particle type are set as pre-calculated values, and the calculated values ​​for the scattering intensity and the second-order autocorrelation function are obtained.

[0546] On the other hand, in step S42, the measured value of the scattering intensity at each scattering angle is obtained. Furthermore, the second-order autocorrelation function g is measured for each scattering angle. （2） (τ).

[0547] In the optimization process (step S44), the measured value from step S42 and the pre-calculated value from step S54 are compared and fitted. In this case, for example, similar to the third example of fitting, the difference of the second-order autocorrelation function obtained for each scattering angle and the difference of the total scattering intensity at the scattering angle are used. For example, the evaluation value is obtained by adding the square of the difference of the second-order autocorrelation function obtained for each scattering angle and the square of the difference of the total scattering intensity at the scattering angle for all scattering angles.

[0548] To minimize the evaluation value, refractive index data for candidate particle types are retrieved from the library (step S50). The particle size distribution of the candidate particle types is then defined (step S52). Scattering intensity and second-order autocorrelation function are calculated for each candidate particle type (step S54). A combination of the number of particles with the minimum evaluation value, the candidate material with the minimum evaluation value, and the number of particle types within the candidate material is obtained. This combination is taken as the optimal solution to obtain the final number of particle types contained in the dispersion, the refractive index of each particle type, and the particle size distribution combination (step S46). Thus, as an analysis result, the number of particle types contained in the dispersion and the material of each particle type can be determined (step S48).

[0549] Furthermore, a genetic algorithm is used, for example, in obtaining the pre-calculated value (step S54) and in the selection of candidate materials for each particle type (step S52). Also, a genetic algorithm is used, for example, in the optimization of the particle size distribution (step S44), i.e., fitting. In the above steps, by using a genetic algorithm, the reliability of the selection of the number of particle types and candidate materials for each particle type (step S52) is increased. Furthermore, the reliability of the optimization of the particle size distribution (step S44) is also increased.

[0550] In addition, the number of particle types contained in the dispersion can be predetermined. That is, the number of particle types can be predetermined as a convergence condition. In this case, in step S50, the refractive index data of the candidate particle types are taken out with the predetermined number of particle types (step S50), the candidates for materials of each particle type are selected (step S52), and pre-calculation is performed (step S54).

[0551] (The third example of fitting)

[0552] Compared to the second example of fitting, as mentioned above, the third example of fitting differs in that it selects the number of particle types and candidates for each particle type from a library of material refractive indices and uses their refractive indices.

[0553] In the third example of the fitting, to determine the particle number, the difference in the second-order autocorrelation function obtained for each scattering angle and the difference in the total scattering intensity at each scattering angle are used. For example, an evaluation value is obtained by adding the square of the difference in the second-order autocorrelation function obtained for each scattering angle and the square of the difference in the total scattering intensity at each scattering angle. The particle number that minimizes this evaluation value is then determined.

[0554] In the fitting process, to minimize the evaluation value, the number of particle types, the relative complex refractive index m of each particle type, and the number of particles are repeatedly updated in equations (23) and (24) corresponding to the number of particle types to obtain the final number of particles and the relative complex refractive index m. This is equivalent to step S26 above. In the fitting process, when repeatedly updating the number of particle types, the relative complex refractive index m of each particle type, and the number of particles in a way that minimizes the evaluation value, a genetic algorithm is used, for example, to update the number of particle types, the relative complex refractive index m of each particle type, and the number of particles. As a result, the number of particle types, the relative complex refractive index m of each particle type, and the number of particles can be updated more reliably.

[0555] In the fitting process, the formula representing the relative complex refractive index m is updated in the formulas (23) and (24) corresponding to the number of particle species, as described above, to fit the measured values ​​with the calculated values, thereby obtaining the final number of particles and the relative complex refractive index m. The refractive index is fitted by the formula representing the relative complex refractive index m.

[0556] In the third example of the fitting, the particle size in equation (23) is also inconsistent with that in equation (24). Therefore, in equations (23) and (24), the previously calculated particle size, i.e., the particle size d0 which is independent of the incident light intensity, is also used to make the particle size in equation (23) consistent with that in equation (24). In this state, as described above, the time variation characteristics of multiple scattering electric fields or scattering intensities, and multiple time-averaged scattering electric field data or time-averaged scattering intensity data are fitted to the theoretical formula for the relationship between the specified particle size and scattering intensity to obtain the particle size distribution and relative complex refractive index m.

[0557] As described above, the optimal solution is obtained by taking the number of particles with the minimum evaluation value, the candidate material with the minimum evaluation value, and the number of particle types of the candidate material as the optimal solution, and then obtaining the final combination of the number of particle types, the refractive index of each particle type, and the particle size distribution (step S46). Thus, as an analysis result, the number of particle types and the material of each particle type contained in the dispersion can be determined (step S48).

[0558] The above steps are steps for determining the type of each particle contained in the dispersion.

[0559] Furthermore, in the third example of fitting, the evaluation values ​​used for fitting are not limited to the aforementioned evaluation values.

[0560] Furthermore, in the third example of fitting, similarly to the second example, by changing the measurement wavelength, measurements were performed at multiple measurement wavelengths (two or more) as described above, and the wavelength dependence of the refractive index could be obtained. When changing the measurement wavelength, the measurement wavelength is not limited to two; if multiple wavelengths are used, three or four measurement wavelengths can also be used.

[0561] As described above, the scattered light obtained by repeatedly measuring the incident light intensity after it is incident on a dispersion containing particles is obtained, and multiple scattered intensity data are obtained. Then, the multiple scattered intensity data are converted into multiple scattered electric field or time variation characteristic data of scattered intensity, but it is not limited to this.

[0562] For example, it is also possible to repeatedly measure the scattered light obtained by changing the intensity of the incident light, and obtain multiple time-varying characteristic data of the scattered electric field or the scattered intensity from multiple scattered light. In this case, for example, in a light measurement apparatus, by using an automatic correlator (correlation meter) in the detection of the scattered light, it is not necessary to obtain the scattered intensity data by the measurement unit, but to convert the signals of the scattered light obtained from multiple measurements into multiple time-varying characteristic data of the scattered electric field or the scattered intensity, for example, multiple autocorrelation functions can be obtained. In this case, the scattered light is measured only multiple times in the measurement process. As described above, the multiple autocorrelation functions obtained by converting the signals of the scattered light obtained from multiple measurements are used to determine the particle size and particle size distribution.

[0563] Furthermore, the placement of the light measurement device in the automatic correlator is not particularly limited as long as it can detect the scattered light and obtain the signal of the scattered light.

[0564] As mentioned above, if the autocorrelation function can be obtained from the scattered light without obtaining the scattered intensity data, the autocorrelation is not particularly limited, and commercially available autocorrelation can be used appropriately.

[0565] The present invention is basically constructed as described above. The photometric method and photometric apparatus of the present invention have been described in detail above, but the present invention is not limited to the above embodiments. Various modifications or alterations can be made without departing from the spirit of the present invention.

[0566] Symbol Explanation

[0567] 10a, 10b, 10c, 10d - Autocorrelation function; 10e, 10f, 10g - Autocorrelation function; 12, 13, 14, 15, 16, 17, 18 - Linear lines; 20, 20a, 20b - Photometric device; 22 - Light source; 23a, 23b, 23c, 23d, 23e, 23f - Optical fiber; 23g, 23h, 23i, 23j, 23k, 23m - Optical fiber; 2 4 - First coupler; 24a, 24b, 34a, 34b, 45a, 45b - End faces; 26 - Circulator; 28 - Collimating lens; 30 - Objective lens; 32 - Sample cell; 34 - Second coupler; 36 - Detector; 37 - Measuring section; 38 - Processing section; 38a - Conversion section; 38b - Particle size calculation section; 38c - Particle size distribution calculation section; 38d - Calculation section; 40 - First collimating lens; 4 2-Modulator, 43-Second collimating lens, 44-Phase modulation unit, 45-Third coupler, 46-Measurement unit, 50-Low coherence interferometer, 52-Detection unit, 52a-First detection unit, 52b-Second detection unit, 54-Conversion unit, 55-Storage unit, 61a, 61b, 61c, 61d-Beam splitters, 61e-Transmission and reflection surface, 62-Reflector, 62a-Reflection surface 63a - Dispersion protection adjustment section, 63b - Objective lens, 64a, 64b - ND filters, 65 - Objective lens, 66 - Polarization adjustment section, 67 - Spectral adjustment section, 68 - Polarization control section, 70 - Mirror, 72 - Diffraction grating, 73, 74 - Photodetectors, 84, 85, 86, 87 - Distribution, Ld - Scattered light, Lq - Dispersion liquid, Lr - Reference light, Ls - Incident light, θb - Scattering angle.

Claims

1. A photometric method, which is a photometric method for a dispersion containing particles, the photometric method comprising: The measurement process involves repeatedly measuring the scattered light obtained by changing the intensity of the incident light before it is incident on the dispersion. The conversion process converts the scattered light signal obtained from multiple measurements in the measurement process into time-varying characteristic data of multiple scattered electric fields or scattered intensities. and The particle size calculation step uses the time-varying characteristic data of the multiple scattering electric fields or scattering intensities obtained through the conversion step to determine the particle size.

2. The photometry method according to claim 1, wherein, In the particle size calculation process, it is assumed that the diffusion coefficient of the particle is linearly dependent on the intensity of the incident light. The time variation characteristics of the multiple scattering electric fields or scattering intensities are analyzed to determine the particle size or the relationship between the particle's diffusion coefficient and the intensity of the incident light, and the particle size is then calculated.

3. The photometry method according to claim 2 further comprises the following steps: The second temperature is obtained after the temperature of the particle rises due to the light absorption of the incident light, having reached the first temperature; and Using the particle size obtained in the particle size calculation process, the particle size at the second temperature is calculated using a formula representing the diffusion coefficient when the temperature rises.

4. A photometric method, which is a photometric method for a dispersion containing particles, the photometric method comprising: The measurement process involves repeatedly measuring the scattered light obtained by changing the intensity of the incident light before it is incident on the dispersion. The conversion process converts the scattered light signal obtained from multiple measurements in the measurement process into time-varying characteristic data of multiple scattered electric fields or scattered intensities; and The particle size distribution calculation step uses the time variation characteristic data of the multiple scattering electric fields or scattering intensities obtained through the conversion step to determine the particle size distribution.

5. The photometry method according to claim 4, wherein, The particle size distribution calculation process also includes the following steps: The time-varying characteristics of the multiple scattered electric fields or scattering intensities are used to determine the index value representing the temperature dependence of the particle size; and The particle size distribution of the particles obtained in the particle size distribution calculation step is corrected using the index value representing the temperature dependence of the particle size.

6. The photometry method according to claim 4, further comprising the step of obtaining a second temperature after the temperature of the particle rises due to the light absorption of the incident light, having previously been determined to be at a first temperature. In the particle size distribution calculation process, the second temperature is used to determine the particle size distribution based on the diffusion coefficient obtained from the time variation characteristics data of the multiple scattering electric fields or scattering intensities.

7. The photometry method according to claim 1 or 4, wherein, The scattered light is the incident light obtained by changing the value of at least one of the measurement parameters, the scattering angle and the measurement wavelength.

8. The photometry method according to claim 1 or 4, wherein, The measurement process involves repeatedly measuring the scattered light intensity obtained by altering the intensity of the incident light before it is incident on the dispersion, thereby obtaining multiple scattered light intensity data. The conversion process is a process of obtaining multiple time-varying characteristic data of scattering electric field or scattering intensity from the multiple scattering intensity data obtained through the measurement process.

9. The photometry method according to claim 7, wherein, The dispersion contains a variety of particle types. The optical measurement method has the following characteristics: The conversion process converts the signals of multiple scattered light obtained through the measurement process into multiple time-averaged scattered electric field data or time-averaged scattered intensity data. and The calculation process involves calculating the particle size or particle size distribution of each of the various particle types based on the time-averaged scattered electric field data or the time-averaged scattered intensity data and the time-varying characteristic data.

10. The photometry method according to claim 9, wherein, The measurement process involves repeatedly measuring the scattered intensity of the incident light after changing its intensity and then incident on the dispersion, thereby obtaining multiple scattered intensity data points. Furthermore, it involves repeatedly measuring the scattered intensity of the incident light after changing the value of at least one of the measurement parameters, the scattering angle and the measurement wavelength, thereby obtaining multiple scattered intensity data points. The conversion process is a process of calculating multiple scattering electric fields or scattering intensity time variation characteristic data based on the multiple scattering intensity data obtained through the measurement process.

11. The light measurement method according to any one of claims 1 to 6, wherein, The time-varying characteristics of the scattered electric field or scattering intensity are autocorrelation functions or power spectra.

12. A photometric apparatus, which is a photometric apparatus for a dispersion containing particles, the photometric apparatus comprising: A light source that alters the intensity of incident light before it enters the dispersion; The measuring unit measures the scattered light obtained by repeatedly measuring the incident light after changing its intensity and then incident on the dispersion liquid; The conversion unit converts the scattered light signal obtained from multiple measurements by the measurement unit into time-varying characteristic data of multiple scattered electric fields or scattered intensities; and The particle size calculation unit uses the time-varying characteristic data of the plurality of scattering electric fields or scattering intensities obtained by the conversion unit to calculate the particle size.

13. The light measuring apparatus according to claim 12, wherein, The particle size calculation unit assumes that the diffusion coefficient of the particle is linearly dependent on the intensity of the incident light. It analyzes the time variation characteristics of the multiple scattering electric fields or scattering intensities to determine the particle size or the relationship between the particle's diffusion coefficient and the intensity of the incident light, thereby determining the particle size.

14. The light measuring apparatus according to claim 12, wherein, The particle size calculation unit obtains a second temperature, which is the temperature of the particle after the first temperature rises due to light absorption by the incident light. For the particle size obtained by the particle size calculation unit, the particle size at the second temperature is calculated using a formula representing the diffusion coefficient when the temperature rises.

15. A photometric apparatus, which is a photometric apparatus for a dispersion containing particles, the photometric apparatus comprising: A light source that alters the intensity of incident light before it enters the dispersion; The measuring unit measures the scattered light obtained by repeatedly measuring the incident light after changing its intensity and then incident on the dispersion liquid; The conversion unit converts the signals of the plurality of scattered light obtained by the measurement unit into time-varying characteristic data of the plurality of scattered electric fields or scattered intensities; and The particle size distribution calculation unit uses the time-varying characteristic data of the plurality of scattering electric fields or scattering intensities obtained by the conversion unit to calculate the particle size distribution.

16. The photometric apparatus according to claim 15, wherein, The particle size distribution calculation unit uses the time-varying characteristic data of the multiple scattering electric fields or scattering intensities obtained by the conversion unit to calculate an index value representing the temperature dependence of the particle size. The particle size distribution is corrected using the index value representing the temperature dependence of the particle size.

17. The photometric apparatus according to claim 15, wherein, The particle size distribution calculation unit obtains a second temperature after the temperature of the particle rises due to the light absorption of the incident light from the first temperature, and uses the second temperature to calculate the particle size distribution based on the diffusion coefficient obtained from the time variation characteristics data of the multiple scattering electric fields or scattering intensities.

18. The light measuring apparatus according to claim 12 or 15, wherein, The scattered light is the incident light obtained by changing the value of at least one of the measurement parameters, the scattering angle and the measurement wavelength.

19. The light measuring apparatus according to any one of claims 12 to 17, comprising a measuring unit for measuring the intensity of the incident light.

20. The optical measuring apparatus according to any one of claims 12 to 17, comprising a low-coherence interferometer.

21. The light measuring apparatus according to any one of claims 12 to 17, wherein, The measuring unit repeatedly measures the scattered intensity of the incident light after its intensity has been altered and it has been incident on the dispersion liquid, thereby obtaining multiple scattered intensity data. The conversion unit acquires multiple time-varying characteristic data of the scattering electric field or scattering intensity from the multiple scattering intensity data obtained by the measurement unit.

22. The light measuring apparatus according to claim 18, wherein, The dispersion contains a variety of particle types. The conversion unit converts the signals of multiple scattered light obtained by the measurement unit into multiple time-averaged scattered electric field data or time-averaged scattered intensity data. The particle size calculation unit calculates the particle size of each of the various particle types based on the time-averaged scattering electric field data or the time-averaged scattering intensity data and the time-varying characteristic data.

23. The light measuring apparatus according to claim 18, wherein, The dispersion contains a variety of particle types. The conversion unit converts the signals of multiple scattered light obtained by the measurement unit into multiple time-averaged scattered electric field data or time-averaged scattered intensity data. The particle size distribution calculation unit calculates the particle size distribution of each of the various particle types based on the time-averaged scattering electric field data or the time-averaged scattering intensity data and the time variation characteristic data.

24. The light measuring apparatus according to claim 22, wherein, The measuring unit repeatedly measures the scattered light intensity obtained by changing the intensity of the incident light before it is incident on the dispersion, thereby obtaining multiple scattered light intensity data. Furthermore, it repeatedly measures the scattered light intensity obtained by changing the value of at least one of the measuring parameters, the scattering angle and the measuring wavelength, thereby obtaining multiple scattered light intensity data. The conversion unit is a process of calculating multiple time-varying characteristic data of scattering electric fields or scattering intensities based on the multiple scattering intensity data obtained by the measurement unit.

25. The light measuring apparatus according to any one of claims 12 to 17, wherein, The time-varying characteristics of the scattered electric field or scattering intensity are autocorrelation functions or power spectra.

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