Particle size measurement method, particle size measurement device, and particle size measurement program product

Abstract

The present invention relates to a particle size measurement method, a particle size measurement device, and a particle size measurement program, which set an appropriate measurement time corresponding to a particle size as a measurement object, and save unnecessary measurement time. The particle size measurement method includes: a test measurement step of irradiating a sample with light for a test measurement time including a plurality of measurement time points set in advance, and measuring a test measurement intensity of scattered light scattered by the sample; a self-correlation function calculation step of calculating a self-correlation function representing a relationship between a self-correlation of the test measurement intensity and time; a setting step of setting a part of the measurement time points among the plurality of measurement time points set in advance to be used in a formal measurement, based on a time until the self-correlation function falls below a prescribed threshold and a preliminary time set by adding a time to the time; a formal measurement step of measuring a formal measurement intensity of the scattered light for a formal measurement time including the part of the measurement time points; and a particle size calculation step of calculating a particle size of the sample based on the formal measurement intensity.

Description

Technical Field

[0001] This invention relates to a particle size determination method, a particle size determination device, and a particle size determination procedure. Background Technology

[0002] As a method for determining the size of colloidal particles (hereinafter referred to as particles) existing in a solution, dynamic light scattering is known. Dynamic light scattering involves irradiating light onto particles undergoing Brownian motion in a solution and calculating the particle size based on variations in the scattered light (see Patent Document 1 below). Furthermore, there are also devices that measure the particle size distribution, representing the relationship between the particle size and frequency of each particle, based on images captured by an imaging element (see Patent Document 2 below).

[0003] In dynamic light scattering methods, the required measurement time varies depending on the particle size. As described in Patent Document 1, when a small particle size sample is used as the measurement target with a fixed measurement time, the measurement time includes useless time, thus unnecessarily increasing the measurement time. Furthermore, when using an imaging element to measure particle size as in Patent Document 2, it is not possible to measure small particle sizes below 100 nm, for example.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2002-296118

[0007] Patent Document 2: Japanese Patent Application Publication No. 2001-74642 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] This invention was made in view of the above-mentioned actual situation, and its object is to provide a particle size measurement method, particle size measurement device and particle size measurement procedure that saves useless measurement time by setting an appropriate measurement time corresponding to the particle size of the object being measured.

[0010] Solution for solving the problem

[0011] To address the aforementioned problems, the particle size determination method disclosed herein includes: a test measurement step, wherein during a test measurement time including a plurality of pre-set measurement times, light is irradiated onto a sample, and the test measurement intensity of the scattered light scattered by the sample is measured; an autocorrelation function calculation step, wherein an autocorrelation function representing the relationship between the autocorrelation of the test measurement intensity and time is calculated; a setting step, wherein based on the time until the autocorrelation function falls below a predetermined threshold and a preparation time set by adding to that time, a portion of the pre-set measurement times used in the formal measurement is set; a formal measurement step, wherein during a formal measurement time including the portion of measurement times, light is irradiated onto the sample, and the formal measurement intensity of the scattered light scattered by the sample is measured; and a particle size calculation step, wherein the particle size of the sample is calculated based on the formal measurement intensity.

[0012] To address the aforementioned problems, the particle size measuring apparatus of this disclosure comprises: a testing and measuring unit that, during a testing and measuring time including a plurality of pre-set measuring times, irradiates a sample with light and measures the testing and measuring intensity of the scattered light scattered by the sample; an autocorrelation function calculation unit that calculates an autocorrelation function representing the relationship between the autocorrelation of the testing and measuring intensity and time; a setting unit that, based on the time until the autocorrelation function falls below a predetermined threshold and a preparation time set by adding that time, sets a portion of the pre-set measuring times to be used in the formal measuring; a formal measuring unit that, during the formal measuring time including the portion of the measuring times, irradiates the sample with light and measures the formal measuring intensity of the scattered light scattered by the sample; and a particle size calculation unit that calculates the particle size of the sample based on the formal measuring intensity.

[0013] To address the aforementioned problems, the particle size determination procedure of this disclosure causes a computer used in a particle size determination apparatus for determining the particle size of a sample to perform: a test determination step, wherein, during a test determination time including a plurality of pre-set determination times, light is irradiated onto the sample, and the test determination intensity of the scattered light scattered by the sample is measured; an autocorrelation function calculation step, wherein an autocorrelation function representing the relationship between the autocorrelation of the test determination intensity and time is calculated; a setting step, wherein, based on the time until the autocorrelation function falls below a predetermined threshold and a preparation time set by adding to that time, a portion of the pre-set determination times used in the formal determination is set; a formal determination step, wherein, during the formal determination time including the portion of determination times, light is irradiated onto the sample, and the formal determination intensity of the scattered light scattered by the sample is measured; and a particle size calculation step, wherein the particle size of the sample is calculated based on the formal determination intensity. Attached Figure Description

[0014] Figure 1This is a schematic diagram showing the general configuration of the particle size measuring device according to this embodiment.

[0015] Figure 2 This is a diagram showing an example of the general configuration of the measuring unit in this embodiment.

[0016] Figure 3 This is a diagram showing an example of a channel configuration table.

[0017] Figure 4 This is a graph used to illustrate the sampling time of each channel.

[0018] Figure 5 This is a flowchart illustrating the method for calculating particle size in this embodiment.

[0019] Figure 6 This is a graph representing an example of the autocorrelation function.

[0020] Figure 7 This is a graph representing an example of the autocorrelation function.

[0021] Figure 8 This is a diagram showing an example of a first preparation time setting table.

[0022] Figure 9 This is a diagram showing an example of a second preparation time setting table.

[0023] Figure 10 This is a diagram showing an example of a third preparation time setting table.

[0024] Figure 11 This is a diagram showing an example of a formal measurement time setting table.

[0025] Explanation of reference numerals in the attached figures:

[0026] 100: Particle size measuring device; 102: Information processing unit; 104: Measuring unit; 106: Control unit; 108: Storage unit; 110: Display unit; 112: Input / output unit; 114: Data bus; 116: Autocorrelation function calculation unit; 118: Setting unit; 120: Particle size calculation unit; 122: Test and measurement unit; 124: Formal measurement unit; 202: Light source; 204: Sample holder; 206: Pinhole; 208: Light receiving unit; 210: Laser; 212: Particles contained in the sample; 214: Scattered light. Detailed Implementation

[0027] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings.

[0028] Figure 1 This is a schematic diagram showing the general configuration of the particle size measuring device 100 according to this embodiment. Figure 1As shown, the particle size measuring device 100 of this embodiment includes an information processing unit 102 and a measuring unit 104. The information processing unit 102 includes a control unit 106, a storage unit 108, a display unit 110, and an input / output unit 112. The information processing unit 102 is, for example, a general-purpose computer. The control unit 106, the storage unit 108, the display unit 110, and the input / output unit 112 are connected via a data bus 114 to exchange electrical signals with each other.

[0029] The control unit 106 is a CPU (Central Processing Unit) that functions as a processor. Specifically, the control unit 106 functionally includes an autocorrelation function calculation unit 116, a setting unit 118, and a particle size calculation unit 120. Each unit performs the operations described later according to the program stored in the storage unit 108.

[0030] Storage unit 108 includes main storage devices such as RAM (Random Access Memory) and auxiliary storage devices such as HDD (Hard Disk Drive) and SSD (Solid State Drive) capable of statically recording information. In addition to storing particle size measurement programs, storage unit 108 stores programs for controlling the operation of each unit included in information processing unit 102. Furthermore, storage unit 108 pre-stores the tables described later.

[0031] Display unit 110 is a CRT (Cathode Ray Tube), a flat panel display, etc. Display unit 110 visually displays images to the user.

[0032] Input / output unit 112 is one or more devices such as a keyboard, mouse, and touch panel for user input of information. Input / output unit 112 is also one or more interfaces for exchanging information between information processing unit 102 and external devices such as measurement unit 104. For example, input / output unit 112 receives the results measured by measurement unit 104. Input / output unit 112 may include various ports for wired connections and controllers for wireless connections. It should be noted that the configuration of information processing unit 102 shown here is an example, and other configurations are possible.

[0033] The measuring unit 104 functionally includes a test measuring unit 122 and a formal measuring unit 124. The test measuring unit 122, within a test measuring time that includes multiple preset measuring moments, irradiates the sample with light and measures the intensity of the scattered light 214 (described later) scattered by the sample. The formal measuring unit 124, within a formal measuring time, irradiates the sample with light and measures the intensity of the scattered light 214 scattered by the sample, wherein the formal measuring time includes a portion of the measuring moments included in the test measuring time. Detailed descriptions of the functions of the test measuring unit 122 and the formal measuring unit 124 will be provided later. Figure 2 This is a schematic diagram showing a general outline of the hardware configuration of the measuring unit 104. It should be noted that the hardware configuration of the measuring unit 104 is known, therefore only a simplified explanation is provided.

[0034] like Figure 2 As shown, the measuring unit 104 includes a light source 202, a sample holder 204, a pinhole 206, and a light-receiving unit 208. The light source 202 is, for example, a semiconductor laser generating device that emits a laser beam 210 of a given wavelength. The sample holder 204 is equipped with a sample, which is the object of measurement. The sample is in a liquid state and includes particles 212 undergoing Brownian motion. The laser beam 210 emitted by the light source 202 irradiates and scatters the particles 212 contained in the sample. The scattered light 214 enters the light-receiving unit 208 through the pinhole 206.

[0035] The light-receiving unit 208 counts the number of incident photons over a set time period, thereby measuring the time change in the intensity of the scattered light 214. Specifically, the light-receiving unit 208 includes: a semiconductor detector, which is a multi-channel analyzer and corresponds to each channel; and a counter that counts the number of photons detected by each semiconductor detector. The light-receiving unit 208 counts the number of incident photons during the specified period for each channel, thereby measuring the time change in the intensity of the scattered light 214.

[0036] In this embodiment, the measurement unit 104 operates based on the relationship between sampling time, start delay, end delay, number of channels, and cumulative number of channels stored in the storage unit 108. Specifically, for example, the storage unit 108 stores data such as... Figure 3 The table shown illustrates the relationship between group, sampling time, start lag, end lag, number of channels (ch), and cumulative number of channels (ch). The following will... Figure 3 The table shown is a channel setting table.

[0037] A group is a number representing a group of channels that have the same sampling time. The sampling time is the time it takes for each channel to count the number of photons, set for each channel individually. The start lag for each group is the time from the start of the measurement to the earliest of the times when all channels in that group finish sampling. The end lag for each group is the time from the start of the measurement to the latest of the times when all channels in that group finish sampling. The number of channels indicates the number of channels included in each group. The cumulative channel count represents the total number of channels included in the corresponding group plus all channels included in groups with smaller numbers. It should be noted that by setting the number of channels and sampling time for each group, other items are set to specified values ​​corresponding to the number of channels and sampling time.

[0038] Based on the instructions of the control unit 106, the measuring unit 104 uses a method belonging to... Figure 3 The measurement is performed using channels from 1 to a set group. Specifically, for example, using... Figure 4 The following describes the case where the measurement unit 104 receives an instruction from the control unit 106 to perform the measurement using channels belonging to groups 1 to 10. In this case, the measurement unit 104 first uses the 50 channels belonging to group 1 to count the number of photons.

[0039] Here, the start time for measurement (hereinafter referred to as the measurement time) is set for each channel belonging to Group 1, with sampling times that are non-repeating and continuous. For example... Figure 3 As shown, the sampling time for each channel in Group 1 is 0.1 μs, the start latency of Group 1 is 0.1 μs, the end latency is 5 μs, and the number of channels in Group 1 is 50. Therefore, as... Figure 4 As shown, each channel in group 1 counts the number of photons sequentially during a period of 5 μs from the moment when the measurement unit 104 starts the measurement according to the start measurement instruction from the control unit 106.

[0040] Then, after the sampling time of the channel with the latest measurement time included in Group 1 has ended, the channels belonging to Group 2 begin sampling in a manner where the sampling time is non-repeating and continuous. Similarly to Group 1, the number of photons in each channel belonging to Group 2 is counted sequentially in a 10μs period in a manner where the sampling time is non-repeating and continuous.

[0041] Similarly, each channel in groups 3 to 10 counts the number of photons sequentially. As a result, the measuring unit 104 uses each channel in groups 1 to 10 to count the number of photons. Figure 3 The measurement was performed during the 4000 μs delay period at the end of group 10. The results measured by the measuring unit 104 were expressed as the relationship between intensity (the number of photons counted, in cps) and time.

[0042] Next, use Figure 5 The flowchart shown explains the particle size measurement method of this embodiment and the functions of each part included in the control unit 106. First, the user determines whether the particle size value of the particles 212 contained in the sample has been entered (S502).

[0043] In S502, if no particle size value is input, the setting unit 118 sets the measurement time to be used in the test measurement based on a preset relationship between particle size and measurement time (S504). Specifically, for example, the setting unit 118 sets the time preset in the storage unit 108. Figure 3 All measurement times are shown. Here, the test measurement time, including all measurement times, is 1,800,000 μs. This is set by sending an instruction from the control unit 106 to the measurement unit 104 to perform measurements using all channels belonging to groups 1 to 18.

[0044] Next, the input / output unit 112 receives the input of the number of test measurements (S506). Specifically, for example, the user operates the input / output unit 112, thereby receiving five such test measurements. It should be noted that ideally, the number of input test measurements is less than the number of measurements performed in the past to calculate particle size. As will be described later, the overall measurement time can be shortened by reducing the number of test measurements.

[0045] Next, if the number of tests input in S506 is not zero, proceed to S508; if the number of tests input is zero, proceed to S517 (S507). If the number of tests input is not zero, the test measurement unit 122 illuminates the sample with light within a set test measurement time and measures the test measurement intensity of the scattered light 214 scattered by the sample (S508). Specifically, the test measurement unit 122 counts the number of photons sequentially incident on the detectors corresponding to channels 1 to 480, thereby measuring the time change in the intensity of the scattered light 214 within 1,800,000 μs. Furthermore, the test measurement unit 122 performs this measurement five times as input in S506. It should be noted that while it is preferable to perform multiple measurements of the test measurement intensity in test measurement step S508, it can also be performed once.

[0046] Next, the autocorrelation function calculation unit 116 calculates the autocorrelation function representing the relationship between the autocorrelation of the test measurement intensity and time. Specifically, for example, when the test measurement intensity is set to I(t), the autocorrelation function calculation unit 116 uses Equation 1 to calculate the autocorrelation function G2(τ).

[0047] [Formula 1]

[0048]

[0049] For example, Figure 6 This is a diagram showing an example of the autocorrelation function calculated by the autocorrelation function calculation unit 116 based on the measured intensity. (See diagram for example.) Figure 6 As shown, the autocorrelation function reaches its maximum value at the measurement time of 0, gradually decays, and converges to 1 at the time corresponding to the particle size.

[0050] Next, the particle size calculation unit 120 calculates the particle size of the sample based on the test intensity (S512). Specifically, the particle size calculation unit 120 calculates the diffusion coefficient based on the autocorrelation function calculated in S510. Furthermore, the particle size calculation unit 120 calculates the particle size based on the test intensity according to the diffusion coefficient and the Stokes-Einstein formula. If the test intensity is measured multiple times, the particle size calculation unit 120 calculates the average value of the particle size calculated for each test intensity, or it can calculate the maximum value.

[0051] Next, the setting unit 118 sets a portion of the measurement times used in the formal measurement among a plurality of preset measurement times based on the time until the autocorrelation function falls below a predetermined threshold and a preparation time set by adding that time (S514).

[0052] Specifically, firstly, the setting unit 118 sets a base time based on the time until the autocorrelation function falls below a predetermined threshold. For example, Figure 7 It is Figure 6 A magnified graph showing the time around which the autocorrelation function converges to 1. (See image.) Figure 7 As shown, the autocorrelation function is below the threshold of 1.003 at 1000 μs, so the setting unit 118 sets the base time to 1000 μs. Then, the setting unit 118 sets the group corresponding to the base time. For example, the setting unit 118 refers to the setting table and sets group 8, which includes the group with the base time of 1000 μs and the fewest cumulative channels, as the group corresponding to the base time.

[0053] It should be noted that, as mentioned above, the number of tests performed is less than the number previously performed to calculate particle size. Therefore, the particle size calculated based on the test intensity in S512 as the particle size of the sample is a low-precision value. However, the particle size calculated based on the test intensity in S512 is sufficiently accurate as a value used to set the baseline time.

[0054] Furthermore, the setting unit 118 sets the preparation time based on the number of test measurements, the particle size calculated according to the test measurement intensity, and the test measurement intensity. Specifically, the setting unit 118 sets change values ​​for a group corresponding to the preparation time.

[0055] For example, the setting unit 118 sets the change value in such a way that the fewer the number of test measurements, the longer the preparation time. Figure 8 This is a first preparation time setting table that represents the relationship between the number of test measurements and the change value of the group. As described above, when the number of test measurements is five, the setting unit 118 sets the change value corresponding to the number of test measurements to 1. When the number of test measurements is low, the accuracy of the test measurements is likely to be low. Therefore, by using the first preparation time setting table, even when the number of test measurements is low, it is possible to avoid situations where times below a threshold are not included in the actual measurement time.

[0056] In addition, the setting unit 118 sets a change value in such a way that the smaller the particle size is calculated based on the strength measured by the test, the longer the preparation time is. Figure 9 This is a second preparation time setting table that represents the relationship between the particle size calculated based on the test measurement intensity and the group's change value. For example, if the particle size calculated based on the test measurement intensity in S512 is 2 μm, the setting unit 118 sets the change value corresponding to the particle size calculated based on the test measurement intensity to 0. Although smaller particle sizes can shorten the formal measurement time, in the case of small particle sizes, the base time is sometimes set to be extremely short. In this case, the time below the threshold may not be included in the formal measurement time due to the accuracy of the test measurement, but this can be avoided by using the second preparation time setting table.

[0057] In addition, the setting unit 118 sets a change value in such a way that the smaller the average value of the measured intensity, the longer the preparation time. Figure 10 This is a third preparation time setting table that represents the relationship between the test measurement intensity and the change value of the group. For example, if the test measurement intensity measured in S508 is 5 million cps, the setting unit 118 sets the change value corresponding to the test measurement intensity to 1. When the test measurement intensity is low, the accuracy of the test measurement is likely to be low. Therefore, by using the third preparation time setting table, even when the accuracy of the test measurement is low, the situation where time below the threshold is not included in the formal measurement time can be avoided.

[0058] The setting unit 118 adds the total value of the changes set in the first to third preparation time setting tables to the group number corresponding to the base time. In the example above, the group number 8, which is determined to be the group corresponding to the base time, is added to the total value of the changes 2 to calculate 10. Then, the setting unit 118 sets the measurement time of each channel included in groups 1 to 10 as the measurement time to be used in the actual measurement. Here, the actual measurement time including this measurement time is 4000 μs. The control unit 106 sends an instruction to the measurement unit 104 to use all channels belonging to groups 1 to 10 for measurement, thereby performing the setting implemented by the setting unit 118.

[0059] Here, we return to the explanation of the case where the particle size value has already been input in S502. In S502, when the particle size value has already been input, the setting unit 118 sets the measurement time to be used in the actual measurement based on a preset relationship between the particle size and the measurement time (S516). Specifically, for example, the setting unit 118 refers to... Figure 11 The formal measurement time setting table shown is used to set the measurement time used in the formal measurement. For example, if the value input in S502 is 500nm, the setting unit 118 sets the measurement time of each channel included in groups 1 to 14 as the measurement time used in the formal measurement. Similarly to S514, the control unit 106 sends an instruction to the measurement unit 104 to use all channels belonging to groups 1 to 14 for measurement, thereby performing the setting implemented by the setting unit 118. In this case, the test measurement step itself is not performed, thereby further shortening the measurement time since the estimated particle size is known in advance.

[0060] Furthermore, if it is determined in S507 that the number of test measurements is zero, the setting unit 118 sets all measurement times to the measurement times used in the actual measurement (S517). Specifically, for example, the setting unit 118 sets the values ​​pre-stored in the storage unit 108. Figure 3 All measurement times are shown. Here, the total test measurement time, including all measurement times, is 1,800,000 μs. The control unit 106 sends an instruction to the measurement unit 104 to perform the measurement using all channels belonging to groups 1 to 18, thereby performing the setting implemented by the setting unit 118. In this case, even without inputting the particle size, the formal measurement can be performed according to the input time of the number of tests. Therefore, the user can control the start time of the formal measurement.

[0061] Next, during the formal measurement time, the formal measurement unit 124 irradiates the sample with light and measures the formal measurement intensity of the scattered light 214 scattered by the sample (S518). Specifically, the formal measurement unit 124 performs the formal measurement based on the measurement time set in S514, S516, or S517. As in the example above, when the measurement time of each channel included in groups 1 to 10 is set, the formal measurement unit 124 counts the number of photons sequentially incident on the detectors corresponding to channels 1 to 300, thereby measuring the time change of the intensity of the scattered light 214 within 4000 μs.

[0062] Furthermore, the formal measurement unit 124 performs formal measurements using a preset number of measurements to accurately determine particle size. The number of formal measurements can be fixed or determined by the user through input to the input / output unit 112, but it is set to be more than the number of test measurements.

[0063] Next, the particle size calculation unit 120 calculates the particle size of the sample based on the formal measurement intensity. Specifically, for example, the particle size calculation unit 120 calculates the particle size of the sample using the measurement results from S518, following the same method as in step S512. Since the formal measurement intensity is measured multiple times, the particle size calculation unit 120 calculates the average value of the particle size calculated under each formal measurement intensity.

[0064] As described above, according to this embodiment, by setting the formal measurement time to be shorter than the test measurement time, the measurement can be completed in a short time without reducing the measurement accuracy. For example, in a particle size measuring apparatus 100 that requires 25 measurements to obtain a certain measurement accuracy, if all channels included in the channel setting table are used for measurement as in the prior art, 25 measurements of 1,800,000 μs are required. In this case, the overall measurement time is approximately 45 seconds. On the other hand, as in the above embodiment, if the test measurement of 1,800,000 μs is performed five times and the formal measurement time of 4,000 μs is performed 25 times, the overall measurement time is approximately 9 seconds. Therefore, the measurement time can be shortened while maintaining the number of autocorrelation functions used to calculate the particle size.

[0065] It should be noted that the present invention is not limited to the solutions described in the above embodiments. For example, Figure 3 The channel setting table and preparation time setting table shown are examples, and appropriate settings can be made for each particle size measuring device 100. For example, to achieve higher time resolution with shorter measurement time, Figure 3 The settings table shown is configured such that the sampling time increases exponentially with the group number. However, it can also be set so that the sampling time increases proportionally to the group number, or it can be set so that the sampling time is the same for all groups.

[0066] Furthermore, all cases of using the first to the third preparation time setting tables have been explained, but it is also possible to set the actual measurement time using only the base time without using all the preparation time setting tables, or to use only a portion of the preparation time setting tables to set the actual measurement time.

[0067] Furthermore, while the above explanation focused on setting the formal measurement time on a group basis, it is also possible to set the formal measurement time on a channel basis. In this case, the required time for the formal measurement can be set more accurately, thus further shortening the measurement time.

Claims

1. A method for determining particle size, comprising: The testing and measurement steps involve irradiating the sample with light within a testing and measurement time that includes multiple preset measurement times, and measuring the intensity of the scattered light scattered by the sample. The testing and measurement time is divided into multiple consecutive groups, each group corresponding to multiple channels and having a predetermined constant sampling time. The sampling time of the first group is the shortest, and the sampling time of subsequent groups increases progressively. The autocorrelation function calculation steps involve calculating an autocorrelation function that represents the relationship between the autocorrelation of the measured intensity and time. The setting steps involve setting a subset of groups that are fewer than the total number of groups for the test measurement time as the groups for the formal measurement. The number of groups in the last group of the formal measurement is determined based on the time required for the autocorrelation function to drop to a specified threshold and the preparation time set by adding that time. The formal measurement procedure includes, within the formal measurement time including the aforementioned subsets, irradiating the sample with light and measuring the formal measurement intensity of the scattered light scattered by the sample; and The particle size calculation step involves calculating the particle size of the sample based on the formally measured strength.

2. The particle size determination method according to claim 1, characterized in that, In the test measurement step, the intensity of the test measurement is measured multiple times. The fewer the number of test measurements, the longer the preparation time.

3. The particle size determination method according to claim 1, characterized in that, In the test measurement step, the intensity of the test measurement is measured multiple times. The smaller the average value of the measured intensity in the test, the longer the preparation time is set.

4. The particle size determination method according to claim 1, characterized in that, The particle size determination method further includes the step of calculating the particle size of the sample based on the test intensity. The smaller the particle size calculated based on the intensity determined by the test, the longer the preparation time is set.

5. A particle size measuring device, comprising: The testing and measurement unit, within a testing and measurement time including multiple preset measurement moments, irradiates the sample with light and measures the intensity of the scattered light scattered by the sample. The test measurement time is divided into multiple consecutive groups, each group corresponding to multiple channels and having a predetermined constant sampling time, wherein the sampling time of the first group is the shortest, and the sampling time of the subsequent groups increases in turn. The autocorrelation function calculation unit calculates an autocorrelation function that represents the relationship between the autocorrelation of the measured intensity and time. The setting unit sets a subset of groups that are fewer than the total number of groups for the test measurement time as the groups for the formal measurement. The number of groups in the last group of the formal measurement is determined based on the time required for the autocorrelation function to drop to a specified threshold and a preparation time set by adding that time. The formal measurement unit, during the formal measurement time including the aforementioned group of parts, irradiates the sample with light and measures the formal measurement intensity of the scattered light scattered by the sample. as well as The particle size calculation unit calculates the particle size of the sample based on the formally measured strength.

6. A particle size determination program product, comprising a particle size determination program that causes a computer used in a particle size determination apparatus for determining the particle size of a sample to perform: The testing and measurement steps involve irradiating the sample with light within a testing and measurement time that includes multiple pre-set measurement moments, and measuring the intensity of the scattered light scattered by the sample. The test measurement time is divided into multiple consecutive groups, each group corresponding to multiple channels and having a predetermined constant sampling time, wherein the sampling time of the first group is the shortest, and the sampling time of the subsequent groups increases in turn. The autocorrelation function calculation steps involve calculating an autocorrelation function that represents the relationship between the autocorrelation of the measured intensity and time. The setting steps involve setting a subset of groups that are fewer than the total number of groups for the test measurement time as the groups for the formal measurement. The number of groups in the last group of the formal measurement is determined based on the time required for the autocorrelation function to drop to a specified threshold and the preparation time set by adding that time. The formal measurement procedure involves irradiating the sample with light during the formal measurement time, including the aforementioned partial group, and measuring the formal measurement intensity of the scattered light scattered by the sample. as well as The particle size calculation step involves calculating the particle size of the sample based on the formally measured strength.

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