Observation method, observation apparatus, and program

Abstract

This invention provides observation methods for observing coarse particles in a short amount of time. [Solution] This is an observation method for observing coarse particles in a dispersion liquid in which particles are dispersed in a liquid. The observation method comprises a wave transmission step, a wave reception step, an image generation step, and an analysis step. The wave transmission step transmits ultrasonic waves into the dispersion liquid. The wave reception step receives the reflected waves generated when the transmitted ultrasonic waves are reflected by the particles. The image generation step generates image data based on the received reflected waves. The analysis step analyzes the coarse particles in the dispersion liquid from the generated image data.

Description

Technical Field

[0001] The present invention relates to an observation method, an observation apparatus, and a program.

Background Art

[0002] As a method for observing coarse particles in a dispersion liquid, a method (image analysis method) of irradiating light to the dispersion liquid flowing in a flow cell and imaging scattered light from the coarse particles is known (Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Microbubbles contained in the dispersion liquid immediately after stopping stirring are difficult to distinguish from particles and are likely to be erroneously observed as particles. Therefore, a method of leaving the dispersion liquid until the microbubbles disappear and then observing coarse particles by the image analysis method can be considered. However, in this method, it is necessary to leave the dispersion liquid for several minutes to about 30 minutes after stopping stirring, and it takes time until the observation starts.

[0005] The problem to be solved by the present invention is to provide an observation method, an observation apparatus, and a program for observing coarse particles in a dispersion liquid in a short time.

Means for Solving the Problems

[0006] To solve the above problems, the observation method of the present invention is an observation method for observing coarse particles in a dispersion liquid in which particles are dispersed in a liquid, a wave transmission step of transmitting ultrasonic waves to the dispersion liquid, a wave reception step of receiving a reflected wave generated by reflection of the transmitted ultrasonic waves by the particles, An image generation process that generates image data based on the received reflected wave, and The method includes an analysis step of analyzing the coarse particles in the dispersion from the generated image data.

[0007] The invention described in claim 2 is, in the invention described in claim 1, The particle size of the coarse particles is in the range of 0.01 to 1000 μm.

[0008] The invention described in claim 3 is, in the invention described in claim 1, The particle size of the coarse particles is 10 times or more the desired particle size of the dispersion in the aforementioned dispersion.

[0009] The invention described in claim 4 is, in the invention described in claim 1, In the image generation process described above, B-mode image data is generated, In the analysis step described above, the coarse particles in the dispersion are analyzed from the generated B-mode image data.

[0010] The invention described in claim 5 is, in the invention described in claim 1, In the image generation process described above, power spectral data is generated using the Doppler method. In the analysis step described above, the coarse particles in the dispersion are analyzed from the generated power spectral data.

[0011] The invention described in claim 6 is the invention described in claim 4 or 5, In the analysis step described above, the number of coarse particles in the dispersion is calculated from the generated image data.

[0012] The invention described in claim 7 is, in the invention described in claim 1, The content of the particles in the dispersion is within the range of 0.0001 to 50% by mass relative to the total mass of the dispersion medium.

[0013] The invention according to claim 8 is the invention according to claim 1, wherein While stirring, the coarse particles in the dispersion are observed.

[0014] The observation device of the present invention is An observation device for observing coarse particles in a dispersion in which particles are dispersed in a liquid, comprising A transmitting unit that transmits ultrasonic waves to the dispersion, A receiving unit that receives a reflected wave generated by reflection of the transmitted ultrasonic waves by the particles, An image generation unit that generates image data based on the received reflected wave, and An analysis unit that analyzes the coarse particles in the dispersion from the generated image data.

[0015] The program of the present invention causes A computer of an observation device including a transmitting unit that transmits ultrasonic waves to a dispersion in which particles are dispersed in a liquid, a receiving unit that receives a reflected wave generated by reflection of the transmitted ultrasonic waves by the particles, and an image generation unit that generates image data based on the received reflected wave, To function as an analysis unit that analyzes coarse particles in the dispersion from the generated image data.

Advantages of the Invention

[0016] According to the present invention, coarse particles in a dispersion can be observed in a short time.

Brief Description of the Drawings

[0017] [Figure 1] It is a schematic diagram showing an observation device. [Figure 2] It is a block diagram showing the functional configuration of an observation device. [Figure 3] It is a partial cross-sectional view of an ultrasonic probe. [Figure 4] It is a flowchart of a method for observing coarse particles. [Figure 5] It is a graph showing the measurement results of the dynamic light scattering particle size distribution in dispersion A and dispersion B. [Figure 6] This graph shows the measurement results of dispersion A using a flow-type particle analyzer (FPIA). [Figure 7] This graph shows the measurement results of dispersion B using a flow-type particle analyzer (FPIA). [Figure 8] This is an example of a B-mode image of dispersion A. [Figure 9] This is an example of a B-mode image of dispersion B. [Figure 10] This is a binarized image obtained by processing the B-mode image of dispersion A. [Figure 11] This is a binarized image of the B-mode image in dispersion B. [Figure 12] This is an example of a power spectrum in a dispersion. [Figure 13] This is an example of a power spectrum in a dispersion. [Figure 14] This graph shows the relationship between the number of coarse particles and the intensity of the power spectrum. [Figure 15] This diagram shows a method for observing particles by irradiating a dispersion with light and detecting scattered light from coarse particles. [Modes for carrying out the invention]

[0018] Hereinafter, one or more embodiments of the present invention will be described with reference to the drawings. However, the scope of the present invention is not limited to the disclosed embodiments.

[0019] [Configuration of the observation device] Referring to Figure 1, the overall configuration of the observation device 100 of this embodiment will be described. Figure 1 is a schematic diagram showing the observation device 100 of this embodiment. Note that in the dispersion 30, which is the object of observation, particles are dispersed in the liquid.

[0020] As shown in Figure 1, the observation device 100 comprises an ultrasonic probe 10, a main unit 11, and a connector unit 12. The ultrasonic probe 10 is connected to the main unit 11 via a cable 14 connected to the connector unit 12. A transmission signal (drive signal) as an electrical signal from the main unit 11 is transmitted via the cable 14 to a piezoelectric element 1 (see Figure 2), which is the piezoelectric part of the ultrasonic probe 10. This transmission signal is converted into ultrasonic waves in the piezoelectric element 1, and the ultrasonic waves (incident wave W1) are transmitted to the dispersion liquid 30 flowing through the channel 31. At this time, the piezoelectric element 1 functions as a wave transmitter. The incident wave W1 is reflected by particles (not shown) in the dispersion liquid 30, and a reflected wave W2 is generated. The generated reflected wave W2 is received by the piezoelectric element 1, converted into a received signal as an electrical signal, and transmitted to the main unit 11. At this time, the piezoelectric element 1 functions as a wave receiver. The received signal is converted into ultrasonic image data of the dispersion liquid 30 in the main unit 11 and displayed on the display unit 13.

[0021] The ultrasonic probe 10 is equipped with piezoelectric elements 1 as transducers, and these piezoelectric elements 1 are arranged in a one-dimensional array in the azimuth direction (scanning direction), for example. In this embodiment, for example, an ultrasonic probe 10 equipped with 192 piezoelectric elements 1 is used. The piezoelectric elements 1 may also be arranged in a two-dimensional array. The number of piezoelectric elements 1 can be set arbitrarily. In this embodiment, a convex electronic scan probe is used as the ultrasonic probe 10 to perform ultrasonic scanning using a convex scanning method, but either a linear scanning method or a sector scanning method may be adopted. Communication between the main unit 11 and the ultrasonic probe 10 may be performed by wireless communication such as UWB (Ultra Wide Band) instead of wired communication via cable 14.

[0022] The dispersion 30 is mainly stirred by the stirring blade 33 in the liquid tank 32. A portion of the stirred dispersion 30 flows through the channel 31 in the direction of the arrow and is observed by the observation device 100. In this embodiment, the shape of the channel 31 and the liquid tank 32 is not limited thereto. Nor is the method of stirring the dispersion 30 limited thereto.

[0023] Next, the functional configuration of the observation device 100 will be explained with reference to Figure 2. Figure 2 is a block diagram showing the functional configuration of the observation device 100.

[0024] As shown in Figure 2, the main unit 11 includes, for example, an operation input unit 15, a transmission unit 16, a reception unit 17, an image generation unit 18, an image processing unit 19, a DSC (Digital Scan Converter) 20, a display unit 13, and a control unit 21.

[0025] The operation input unit 15 receives operation input from the operator. The operation input unit 15 is equipped with various switches, buttons, a trackball, a mouse, a keyboard, etc., and outputs operation signals to the control unit 21. This allows for input of commands such as instructing the start of observation. It also allows input of various image parameters for displaying data of the dispersion liquid 30, the object of observation, and ultrasound image data on the display unit 13. The main unit 11 may also be configured to include a touch panel. The touch panel is provided on the display panel of the display unit 13 and receives touch input from the operator.

[0026] The transmitting unit 16, in accordance with the control of the control unit 21, supplies a drive signal, which is an electrical signal, to the ultrasonic probe 10 via the cable 14, causing the ultrasonic probe 10 to generate transmitted ultrasonic waves. The transmitting unit 16 also includes, for example, a clock generation circuit, a delay circuit, and a pulse generation circuit. The clock generation circuit generates a clock signal that determines the transmission timing and transmission frequency of the drive signal. The delay circuit sets a delay time for each individual path corresponding to each piezoelectric element 1, delays the transmission of the drive signal by the set delay time, and focuses the transmitted beam composed of transmitted ultrasonic waves. The pulse generation circuit generates a pulse signal as a drive signal at a predetermined period. The transmitting unit 16 generates transmitted ultrasonic waves by driving a continuous portion (for example, 64 elements) of the multiple (for example, 192) piezoelectric elements 1 arranged on the ultrasonic probe 10. Each time the transmitting unit 16 generates transmitted ultrasonic waves, it performs scanning by shifting the driven piezoelectric elements 1 in the azimuth direction (scanning direction).

[0027] The receiving unit 17 receives the received signal, which is an electrical signal, from the ultrasonic probe 10 via the cable 14, according to the control of the control unit 21. The receiving unit 17 includes, for example, an amplifier, an A / D conversion circuit, and a phase-correcting summing circuit. The amplifier amplifies the received signal at a preset amplification factor for each individual path corresponding to each piezoelectric element 1. The A / D conversion circuit converts the amplified received signal from analog to digital (A / D conversion). The phase-correcting summing circuit adjusts the phase of the A / D converted received signal by giving a delay time for each individual path corresponding to each piezoelectric element 1, and then adds them together (phase-correcting summing) to generate sound line data.

[0028] The image generation unit 18 performs envelope detection processing, logarithmic compression, and other operations on the sound line data from the receiving unit 17, in accordance with the control of the control unit 21. The image generation unit 18 generates B (Brightness) mode image data consisting of pixels having brightness values ​​as received energy by adjusting the dynamic range and gain and performing brightness conversion. In other words, B mode image data represents the strength of the received signal in terms of brightness. In addition to B mode, the image generation unit 18 may also generate ultrasonic image data in other image modes such as A (Amplitude) mode, M (Motion) mode, and Doppler image modes (power spectrum, color Doppler mode, etc.).

[0029] The image processing unit 19 performs image processing on the image data output from the image generation unit 18 according to the various image parameters being set, in accordance with the control unit 21. The image processing unit 19 also includes an image memory unit 19a composed of semiconductor memory such as DRAM (Dynamic Random Access Memory). The image processing unit 19 stores the processed image data in the image memory unit 19a in frame units, in accordance with the control unit 21. The image data in frame units is also called "ultrasonic image data" or "frame image data". The image processing unit 19 outputs the generated image data sequentially to the DSC 20, in accordance with the control unit 21.

[0030] The DSC20, in accordance with the control of the control unit 21, converts the image data received from the image processing unit 19 into an image signal for display and outputs it to the display unit 13.

[0031] The display unit 13 can be a display device such as an LCD (Liquid Crystal Display), CRT (Cathode-Ray Tube) display, organic EL (Electronic Luminescence) display, inorganic EL display, or plasma display. The display unit 13 displays still images or moving images of ultrasonic image data on the display screen according to the image signal output from the DSC 20, in accordance with the control of the control unit 21.

[0032] The control unit 21 includes, for example, a CPU (Central Processing Unit), ROM (Read Only Memory), and RAM (Random Access Memory). The control unit 21 reads various processing programs, such as the system program, stored in the ROM and loads them into the RAM, and controls the operation of each part of the observation device 100 according to the loaded programs. The ROM is composed of non-volatile memory such as semiconductors and stores the system program corresponding to the observation device 100, various processing programs that can be executed on the system program, and various data such as gamma tables. These programs are stored in the form of program code that can be read by a computer, and the CPU sequentially executes operations according to the program code. The RAM forms a work area that temporarily stores various programs executed by the CPU and data related to these programs.

[0033] The control unit 21 may analyze the coarse particles in the dispersion 30 from the image data received from the image processing unit 19. In this case, the control unit 21 functions as an analysis unit. The control unit 21 may display the analysis results on the display unit 13.

[0034] Each part of the observation device 100 can be implemented as a hardware circuit, such as an integrated circuit. An integrated circuit is, for example, an LSI (Large Scale Integration), which is also called an IC (Integrated Circuit), system LSI, super LSI, or ultra LSI depending on the degree of integration. The method of implementing an integrated circuit is not limited to LSIs; it may also be implemented using a dedicated circuit or a general-purpose processor. The method of implementing an integrated circuit may also be implemented using an FPGA (Field Programmable Gate Array) or a reconfigurable processor that allows for the reconfiguration of connections and settings in the circuit cells inside the LSI. Furthermore, each functional block may be executed by software. In this case, the software is stored in one or more storage media such as ROMs, optical discs, or hard disks, and executed by an arithmetic processor.

[0035] Next, an example of the overall structure of the ultrasonic probe 10 will be described with reference to Figure 3. Figure 3 is a partial cross-sectional view of the ultrasonic probe 10.

[0036] As shown in Figure 3, the ultrasonic probe 10 includes a piezoelectric element 1, a ground electrode 2, a signal electrode 3, a backing 4, a reflective layer 5, an acoustic matching layer 6, an electrical terminal for signals 7, and an acoustic lens 8. The ground electrode 2 applies a voltage to the piezoelectric element 1. The ground electrode 2 is located on the front side of the piezoelectric element 1, i.e., the side closer to the object being observed. The signal electrode 3 is located on the back side of the piezoelectric element 1, i.e., the side further away from the object being observed. As shown in Figure 3, the ultrasonic probe 10 is assumed to have X, Y, and Z axes.

[0037] In piezoelectric element 1, multiple piezoelectric elements (vibrators) that transmit ultrasonic waves when a voltage is applied are located in one dimension in the X direction in Figure 3. The thickness of piezoelectric element 1 is preferably in the range of 0.05 to 0.3 mm. Each piezoelectric element includes piezoelectric ceramics, piezoelectric single crystals, and composite piezoelectric elements which are composites of these materials and polymer materials. Examples of piezoelectric ceramics include lead zirconate titanate (PZT) systems. Examples of piezoelectric single crystals include lead niobate magnesium oxide-lead titanate solid solution (PMN-PT) and lead niobate zinc oxide-lead titanate solid solution (PZN-PT).

[0038] The ground electrode 2 is an electrode placed in front of the piezoelectric element 1 using methods such as vapor deposition, sputtering, or silver baking, using gold, silver, etc. The signal electrode 3 is an electrode placed on the back of the piezoelectric element 1 using methods such as vapor deposition, sputtering, or silver baking, using gold, silver, etc. The reflective layer 5 is a layer placed on the back of the signal electrode 3 provided on the piezoelectric element 1. The reflective layer 5 contains a material having a value greater than the acoustic impedance of the piezoelectric element 1. As a result, the piezoelectric element 1 vibrates at a wavelength of one-quarter of the wavelength of the ultrasonic waves transmitted and received by the piezoelectric element 1. The signal electrical terminal 7 is placed in contact with the back side of the reflective layer 5 and connects to an external power supply etc. provided in the main body 11 of the observation device 100 via the signal electrode 3 and the reflective layer 5.

[0039] The acoustic matching layer 6 is a layer for acoustically matching the piezoelectric element 1 and the acoustic lens 8. The acoustic matching layer 6 contains a material having an acoustic impedance that is approximately intermediate between that of the piezoelectric element 1 and the acoustic lens 8. As shown in Figure 3, the acoustic matching layer 6 may consist of four layers: a first acoustic matching layer 6a, a second acoustic matching layer 6b, a third acoustic matching layer 6c, and a fourth acoustic matching layer 6d.

[0040] The first acoustic matching layer 6a preferably contains a material having an acoustic impedance in the range of 8 to 20 MRayls (megarails). Examples of such materials include silicon, quartz, free-machining ceramics, graphite filled with metal powder, and epoxy resin filled with fillers (metals, oxides, etc.).

[0041] The second acoustic matching layer 6b preferably contains a material having an acoustic impedance in the range of 6 to 12 MRayls. Examples of such materials include graphite and epoxy resin filled with fillers (metals, oxides, etc.). The third acoustic matching layer 6c preferably contains a material having an acoustic impedance in the range of 3 to 6 MRayls. Examples of such materials include epoxy resin filled with fillers (metals, oxides, etc.). The fourth acoustic matching layer 6d preferably contains a material having an acoustic impedance in the range of 1.7 to 2.3 MRayls. Examples of such materials include plastic materials mixed with rubber materials and resins filled with silicone rubber powder.

[0042] By creating multiple layers of acoustic matching layers 6 in this manner, the bandwidth of the ultrasonic probe can be broadened. When creating multiple layers of acoustic matching layers 6, it is more preferable that the acoustic impedance of each layer be set so that it approaches the acoustic impedance of the acoustic lens 8 in a stepwise or continuous manner as it approaches the acoustic lens 8. Furthermore, each layer of the multilayered acoustic matching layers 6 may be bonded together with an adhesive commonly used in this art, such as an epoxy adhesive.

[0043] The material for the acoustic matching layer 6 is not limited to the above materials, and may also be aluminum, aluminum alloy, magnesium alloy, Macol glass, glass, fused silica, copper graphite, etc. Alternatively, a resin may be used as the material for the acoustic matching layer 6. Examples of resins include polyethylene, polypropylene, polycarbonate, ABS resin, AAS resin, AES resin, nylon, polyphenylene oxide, polyphenylene sulfide, polyphenylene ether, polyether ether ketone, polyamide-imide, polyethylene terephthalate, epoxy resin, and urethane resin.

[0044] The acoustic lens 8 has an acoustic impedance close to that of the dispersion being observed, and a different sound velocity from that of the dispersion, and includes, for example, a soft polymer material. Examples of soft polymer materials include silicone rubber. By utilizing the refraction caused by the difference in sound velocity between the dispersion and the acoustic lens 8, the ultrasonic waves transmitted from the piezoelectric element 1 are focused, improving the resolution.

[0045] The acoustic lens 8 extends along the Y direction in the figure (a direction perpendicular to the arrangement direction X of the piezoelectric material). When the sound velocity of the acoustic lens 8 is slower than that of the dispersion, the acoustic lens 8 is a cylindrical acoustic lens that is convex in the Z direction, and it focuses the ultrasonic waves in the Y direction and radiates them toward the dispersion, which is the object of observation for the ultrasonic probe 10.

[0046] The reflective layer 5 is located between the piezoelectric element 1 and the signal electrical terminal 7, more specifically, between the signal electrode 3 and the signal electrical terminal 7. The reflective layer 5 broadens the frequency range and increases the sensitivity of the ultrasonic probe 10. The reflective layer 5 contains a material having a higher acoustic impedance than the piezoelectric element 1.

[0047] The backing 4 holds the piezoelectric element 1 and the reflective layer 5, and attenuates the ultrasonic waves transmitted from the piezoelectric element 1 to the back side through the reflective layer 5. The backing 4 typically includes synthetic rubber, natural rubber, epoxy resin, thermoplastic resin, etc., filled with materials to adjust acoustic impedance, attenuation, and heat dissipation.

[0048] The ultrasonic probe 10 may have a window (not shown), which is a protective member for obtaining a three-dimensional ultrasonic image, at a position that covers the side in contact with the flow path of the dispersion liquid. The three-dimensional image is obtained by mechanically rotating, oscillating, or sliding an ultrasonic transmitting / receiving unit having a single piezoelectric element 1 that transmits and receives ultrasonic waves. Alternatively, the three-dimensional image can be obtained by mechanically rotating or oscillating an ultrasonic transmitting / receiving unit that has multiple piezoelectric elements 1 arranged in an array and can be scanned electronically. The ultrasonic probe 10 may have an acoustic medium liquid (not shown) between the window and an acoustic lens 8 or the like, which acoustically matches the window with the transmitting / receiving wavefront of the piezoelectric element 1.

[0049] [Method for observing coarse particles] Figure 4 is a flowchart of the method for observing coarse particles. In the observation method of this embodiment, first, ultrasonic waves (incident wave W1) are transmitted to the dispersion liquid 30, which is the object to be observed, using the ultrasonic probe 10 of the observation device 100 (S1: transmission step). Next, the ultrasonic probe 10 is used to receive the reflected wave W2 generated when the incident wave W1 is reflected by particles from the dispersion liquid 30, which is the object to be observed (S2: reception step). Next, image data is generated based on the reflected wave W2 (S3: image generation step). Coarse particles in the dispersion liquid 30 are analyzed from the generated image data (S4: analysis step).

[0050] The wave transmission process S1 and wave reception process S2 are performed using the piezoelectric element 1 as described above. The image generation process S3 and analysis process S4 will be explained according to the analysis method.

[0051] (Image analysis: B-mode image) In the pulsed echo method, short-duration ultrasonic waves are transmitted, and reflected waves from object boundaries and scattering points with acoustically different properties are received at the same location where the ultrasonic waves were transmitted. This allows for the determination of the distance to the target and the intensity of the reflected waves. In this embodiment, the observation device 100 transmits ultrasonic waves into the dispersion liquid 30. The transmitted ultrasonic waves are reflected by the surfaces of particles in the dispersion liquid 30, generating reflected waves. The larger the particle size, the higher the intensity of the reflected waves generated by the scattering of ultrasonic waves at the particle surface.

[0052] The observation device 100 receives the reflected wave and converts the received ultrasonic waves (reflected waves) into electrical signals (reflected signals). The display methods for the reflected signals acquired by the pulse echo method include A (Amplitude) mode, B (Brightness) mode, and M (Motion) mode. In this embodiment, it is preferable to display the reflected signal using B mode. By using B mode, various information regarding particle size can be acquired.

[0053] In B-mode, luminance modulation is performed to convert the amplitude of the reflected wave into the intensity of brightness on the time axis. The position where the ultrasonic waves are transmitted and received is moved, and the position information of the ultrasonic waves and the time-luminance signal are plotted in two dimensions to display a tomographic image of the target. In this embodiment, the ultrasonic probe 10 is fixed in the flow path 31, and the position where the ultrasonic waves are transmitted and received relative to the dispersion liquid 30 is moved as the dispersion liquid 30 flows through the flow path 31.

[0054] An example of B-mode image data in a dispersion is shown. Dispersion A and dispersion B were prepared. Figure 5 shows the measurement results of the dynamic light scattering particle size distribution for dispersion A and dispersion B. In both dispersion A and dispersion B, a peak is observed around a particle size of 0.11 μm, indicating that the highest number of particles is found around a particle size of 0.11 μm. On the other hand, Figure 6 shows the measurement results of a flow-type particle analyzer (FPIA) for dispersion A. Figure 7 shows the measurement results of a flow-type particle analyzer (FPIA) for dispersion B. When particles larger than 2 μm are defined as coarse particles, it can be seen that dispersion A has fewer coarse particles than dispersion B.

[0055] B-mode image data was acquired for dispersions A and B. The B-mode images were captured as a video at 30 frames per second for 10 seconds (300 frames in total). Figure 8 shows an example of a B-mode image for dispersion A. Figure 9 shows an example of a B-mode image for dispersion B. Figures 8 and 9 are tomographic views of the dispersion 30 flowing through the tubular channel 31. Next, the B-mode images were binarized. Figures 10 and 11 are images obtained by binarizing the tomographic views in Figures 8 and 9, respectively. In the B-mode images, many white areas can be observed in dispersion B compared to dispersion A, meaning that many areas with high reflected wave intensity can be observed, and it can be confirmed that dispersion B contains many more coarse particles than dispersion A.

[0056] Next, for Figures 8 and 9, we counted the number of pixels in the areas corresponding to the dispersion in the tomographic diagrams that had a grayscale level of 30 or higher (30 to 255) when represented in 256 grayscale levels (0 to 255). Figure 12 shows the number of pixels with a grayscale level of 30 or higher in each B-mode image data. In the graph shown in Figure 12, the horizontal axis represents the image number and is marked at intervals of 16 images. The vertical axis represents the number of pixels with a grayscale level of 30 or higher. From both visual observation and the graph data, it can be seen that dispersion B has many more white areas than dispersion A.

[0057] In this embodiment, the particle size of the dispersion to be prepared, more specifically the particle size to be obtained in the dispersion after stirring is finally stopped, is referred to as the "target particle size." Particles larger than the target particle size and with a particle size above a predetermined reference value are referred to as "coarse particles." The reference value for coarse particles is set as appropriate.

[0058] In analysis using B-mode image data, it is preferable that the particle size of coarse particles be 10 times or more than the target dispersion particle size. This creates a clear difference between the pixel gradation originating from particles of the target dispersion particle size and the pixel gradation originating from coarse particles, allowing for more accurate identification of coarse particles.

[0059] Furthermore, in generating B-mode image data, by appropriately controlling the following image generation conditions, a clear difference is created between the pixel gradation originating from particles of the desired dispersion particle size and the pixel gradation originating from coarse particles, allowing for more accurate identification of coarse particles. Image generation conditions include transmission frequency, transmission depth of field, number of transmission focal points, reception bandwidth setting, scanning method, sound velocity, sound line density, frequency compound, spatial compound, image processing, spatial filter, time filter, dynamic range, and gain.

[0060] In analysis using B-mode image data, the target dispersed particle size is preferably in the range of 0.001 to 100 μm, and more preferably in the range of 0.01 to 10 μm. The particle size of coarse particles is preferably in the range of 0.01 to 1000 μm, and more preferably in the range of 1 to 100 μm. By having the target dispersed particle size and the particle size of coarse particles within the above ranges, coarse particles can be identified more accurately.

[0061] (Waveform analysis: Power spectrum) Since particles dispersed in a dispersion are moving objects, the reflected waves generated by these particles undergo a frequency shift due to the Doppler effect. This frequency shift is influenced by the particle's velocity, which in turn is influenced by its particle size. Therefore, by analyzing the frequency change in the reflected wave as a power spectrum, the particle size in the dispersion can be analyzed. This method, which utilizes the difference between the frequency of the transmitted ultrasound and the frequency of the received ultrasound, is called the "Doppler method."

[0062] Furthermore, the larger the particle size, the higher the intensity of the scattered waves (including reflected waves) generated by the scattering of ultrasound at the particle's surface. The frequency shift is also affected by the scattered waves, and the width and shape of the power spectrum change depending on the particle size distribution. Therefore, various information about particle size can be obtained by analyzing the power spectrum.

[0063] Figure 13 shows an example of a power spectrum in a dispersion. The vertical axis of the spectrum graph represents the power spectrum (energy of the reflected wave), and the horizontal axis represents time. The power spectrum was measured at elapsed time while the mixture was continuously stirred in the liquid tank. In the first measurement (after 0 minutes), the overall intensity of the power spectrum is high. In the second (after 30 minutes), third (after 90 minutes), and fourth (after 198 minutes) measurements, the intensity of the power spectrum decreases as the stirring time progresses. Normally, the particle size in the dispersion decreases as the stirring time progresses, so it is thought that the intensity of the power spectrum changes in accordance with the change in particle size.

[0064] For the fourth measurement (after 198 minutes), filtering was performed. Based on the number of spikes and the intensity of the waveform lines in the filtered spectrum, further detailed analysis of the particles in the dispersion is possible.

[0065] In power spectrum analysis, it is preferable that the particle size of coarse particles be at least 10 times larger than the target dispersion particle size. This creates a clear difference between the intensity of the power spectrum originating from particles of the target dispersion particle size and the intensity of the power spectrum originating from coarse particles, allowing for more accurate identification of coarse particles.

[0066] In power spectral analysis, the target dispersion particle size is preferably in the range of 0.001 to 100 μm, and more preferably in the range of 0.01 to 10 μm. The particle size of coarse particles is preferably in the range of 0.01 to 1000 μm, and more preferably in the range of 1 to 100 μm. By having the target dispersion particle size and the particle size of coarse particles within the above ranges, coarse particles can be identified more accurately.

[0067] (Measurement of coarse particle number) The number of coarse particles can be calculated using the following method. A standard sample is prepared that differs only in the number of coarse particles from the observed sample, and the coarse particle number data of the standard sample is acquired by any method (e.g., image analysis). Next, B-mode image data or power spectral data of the standard sample is acquired. A relational expression is calculated from the acquired coarse particle number data and the B-mode image data or power spectral data. B-mode image data or power spectral data is acquired for the dispersion under observation. The acquired B-mode image data or power spectral data is substituted into a pre-calculated relational formula to calculate the number of coarse particles.

[0068] This section describes one example of a method for calculating the number of coarse particles from power spectral data. Several types of CBT dispersions differing only in the number of coarse particles were prepared. The number of coarse particles was varied by adjusting the presence or absence of a desolving agent (NaOH) and the stirring time. Table I below shows the number of coarse particles and the measurement results of the intensity of the averaged power spectrum for each dispersion.

[0069] [Table 1]

[0070] Figure 14 shows a graph illustrating the relationship between the number of coarse particles and the intensity of the averaged power spectrum. The relationship between the number of coarse particles and the intensity of the power spectrum can be approximated here by a linear function. By substituting the measurement data of the observed object into this approximation formula, the number of coarse particles can be calculated.

[0071] (Reducing the effects of microbubbles) Dispersions are obtained by dispersing particulate dispersions in a liquid dispersion medium. Specifically, they are obtained by mixing a liquid dispersion medium with particulate dispersions and stirring. During stirring, the particles disperse, and microbubbles, which are small bubbles with a diameter of about 1 to 10 μm, are generated.

[0072] The effects of microbubbles are known to be wide-ranging. These effects include improved dispersion efficiency, prevention of re-aggregation of particles, adjustment of viscosity in dispersions, particle fragmentation through cavitation, modification of particle surfaces, and removal of impurities. Through these numerous effects, the quality of dispersions can be improved.

[0073] On the other hand, microbubbles are difficult to distinguish from particles. When observing particles in a dispersion, microbubbles were also observed as particles, making it impossible to accurately measure the dispersion particle size.

[0074] Furthermore, microbubbles disappear within a few minutes to 30 minutes. In other words, many microbubbles are present immediately after stirring is stopped, and their number gradually decreases as time passes after stirring is stopped. Therefore, it was found that the measured dispersion particle size fluctuates depending on the time elapsed since stirring was stopped. To address this problem, a method of measuring the dispersion particle size after the microbubbles have disappeared could be considered, but this would require a considerable amount of time, reducing work efficiency.

[0075] In this embodiment, ultrasonic waves are transmitted to the dispersion to observe the particles. When ultrasound waves are transmitted into a dispersion and ultrasonic energy is continuously supplied to microbubbles, the microbubbles gradually grow larger while repeatedly expanding and contracting. Once the microbubbles reach a certain size, they become unstable and can no longer maintain their shape, and they collapse under compression. In this embodiment, by transmitting ultrasound waves into the dispersion, the disappearance of microbubbles is accelerated while observing the particles in the dispersion. As a result, particles can be observed more accurately in a shorter time.

[0076] (Reduction of the effects of concentration) Figure 15 shows a method for observing particles by irradiating a dispersion with light and detecting scattered light from coarse particles. Examples of such methods include image analysis and laser analysis. In this method, light is irradiated from a light source 40, the irradiated light 41 is scattered on the surface of the first particle 42, and the first scattered light 43 is detected. The irradiated light 41 is also scattered on the surface of the second particle 44, and the second scattered light 45 is detected.

[0077] When the second particle 44 is positioned behind the first particle 42 with respect to the light source 40, it is impossible to distinguish whether the first scattered light 43 and the second scattered light 45 originate from the first particle 42 or the second particle 44. For example, in image analysis, an image of the first particle 42 and the second particle 44 as a single unit is formed. In other words, with this method, the positional relationship between the first particle 42 and the second particle 44 in the direction of propagation of the irradiated light 41 cannot be determined, and accurate observation of the particles is difficult unless the concentration in the dispersion is low enough that the particles do not overlap.

[0078] This embodiment is a method for detecting sound waves, not light. In this embodiment, even if multiple particles overlap in the direction of propagation of the transmitted ultrasonic waves, each particle can be observed individually. That is, the first particle 42 and the second particle 44 in Figure 15 can be observed as separate particles. Therefore, the concentration of the dispersion is not limited, and particles can be observed even at high concentrations.

[0079] The particle content as the dispersed phase is preferably in the range of 0.0001 to 50% by mass relative to the total mass of the dispersion medium. In this embodiment, even with a high particle content, i.e., a high concentration, coarse particles can be observed with sufficient accuracy.

[0080] [Examples of application of the present invention] In general manufacturing processes, it is preferable that materials be mixed uniformly. When using a dispersion as a material, it is preferable that the dispersion particle size be uniform. If a large number of particles much larger than the desired dispersion particle size (coarse particles) are present, the performance of the resulting product will be inconsistent, so it is preferable to have as few coarse particles as possible.

[0081] The observation device of this embodiment is preferably used in a manufacturing process that includes a dispersion of materials. For example, coarse particles in the dispersion are observed while stirring, and when it is confirmed that the number of coarse particles is below a predetermined number, stirring of the dispersion is stopped and the dispersion is mixed with other materials. Stirring is continued until the number of coarse particles falls below the predetermined number.

[0082] Specifically, the observation device of this embodiment can be used in the manufacturing process of toner for electrostatic image development. By reducing the number of coarse particles to a predetermined number or less in the preparation of the pigment dispersion, which is the material for the toner for electrostatic image development, a high-quality toner for electrostatic image development can be obtained.

[0083] Furthermore, commonly used pigment dispersions have relatively high concentrations. Therefore, when observing coarse particles using image analysis methods, it is necessary to take a portion of the pigment dispersion from the tank, dilute it, and prepare an observation sample. However, in this embodiment, coarse particles can be observed sufficiently accurately even at relatively high concentrations, eliminating the need to dilute the pigment dispersion. In addition, in this embodiment, the disappearance of microbubbles can be accelerated, allowing for accurate observation of coarse particles in a short time. As a result, the observation device can be directly integrated into the manufacturing line, improving work efficiency in the production of toner for electrostatic image development. Furthermore, this embodiment can be applied to fields other than toner for electrostatic image development.

[0084] This embodiment is an observation method for observing coarse particles in a dispersion 30 in which particles are dispersed in a liquid. The observation method comprises a wave transmission step S1, a wave reception step S2, an image generation step S3, and an analysis step S4. The wave transmission step S1 transmits ultrasonic waves to the dispersion 30. The wave reception step S2 receives the reflected wave W2 generated when the transmitted ultrasonic waves (incident wave W1) are reflected by the particles. The image generation step S3 generates image data based on the received reflected wave W2. The analysis step S4 analyzes the coarse particles in the dispersion 30 from the generated image data. This allows for the observation of coarse particles in a short time.

[0085] In this embodiment, the particle size of the coarse particles is preferably in the range of 0.01 to 1000 μm. This allows for more accurate observation of the coarse particles.

[0086] In this embodiment, it is preferable that the particle size of the coarse particles in the dispersion 30 is 10 times or more than the target dispersion particle size. This allows for more accurate observation of the coarse particles.

[0087] In this embodiment, it is preferable to generate B-mode image data in the image generation step S3 and analyze the coarse particles in the dispersion 30 from the generated B-mode image data in the analysis step S4. This allows for the acquisition of various information regarding particle size and enables more detailed observation of coarse particles.

[0088] In this embodiment, it is preferable to generate power spectral data using the Doppler method in the image generation step S3, and to analyze the coarse particles in the dispersion 30 from the generated power spectral data in the analysis step S4. This allows for the acquisition of various information regarding particle size and enables more detailed observation of coarse particles.

[0089] In this embodiment, it is preferable to calculate the number of coarse particles in the dispersion 30 from the generated image data in the analysis step S4. This allows for more detailed observation of the coarse particles.

[0090] In this embodiment, the particle content in the dispersion 30 is preferably in the range of 0.0001 to 50% by mass relative to the total mass of the dispersion medium. This allows for observation of dispersions with a wide range of concentrations.

[0091] In this embodiment, it is preferable to observe the coarse particles in the dispersion 30 while stirring. This allows for the observation of coarse particles in a short amount of time.

[0092] This embodiment is an observation device for observing coarse particles in a dispersion 30 in which particles are dispersed in a liquid. The observation device 100 has a wave transmitting unit, a wave receiving unit, an image generation unit 18, and an analysis unit. The wave transmitting unit (piezoelectric element 1) transmits ultrasonic waves to the dispersion 30. The wave receiving unit (piezoelectric element 1) receives the reflected wave W2 generated when the transmitted ultrasonic waves (incident wave W1) are reflected by the particles. The image generation unit 18 generates image data based on the received reflected wave W2. The analysis unit (control unit 21) analyzes the coarse particles in the dispersion 30 from the generated image data. This allows for observation of coarse particles in a short time.

[0093] The program of this embodiment causes the computer of the observation device 100 to function as an analysis unit that analyzes coarse particles in the dispersion 30 from the generated image data.

[0094] Furthermore, the detailed configuration and operation of each device constituting the observation apparatus can also be modified as appropriate without departing from the spirit of the present invention.

[0095] Furthermore, the programs for executing each process in each device may be stored on a portable recording medium. Additionally, a carrier wave may be used as the medium for providing program data via a communication line. [Examples]

[0096] The present invention will be described in detail below with reference to examples, but it is not limited to these examples.

[0097] 1. Experiment 1 (1000-fold dilution) The following components were mixed and stirred to prepare carbon black dispersions (CB1-1) and (CB1-2). The prepared dispersions (CB1-1) and (CB1-2) were 1000-fold dilutions of the dispersions (CB2-1) and (CB2-2) described later as stock solutions. The stirring time for (CB1-1) was 100 minutes, and the stirring time for (CB1-2) was 200 minutes.

[0098] Dispersed phase: Carbon black "Mogul® L" (manufactured by Cabot Corporation) Particle size 24μm, specific surface area 138m 2 / g, coloring power index 112, oil absorption 60 (powder), 55 (granular) cc / 100g) 1.0 parts by mass Dispersion medium: pure water 999.0 parts by mass

[0099] The number of coarse particles was measured in each dispersion immediately after preparation (0 minutes later) and 10 minutes later. Here, particles with a diameter of 6 μm or larger were defined as coarse particles. Measurements were performed using three methods: the measurement method of this embodiment (ultrasonic measurement method), image analysis method, and laser analysis method. In the ultrasonic measurement method, the power spectrum was obtained using the method described above, and the number of coarse particles was calculated from an approximation formula between the obtained power spectrum and the number of coarse particles. Furthermore, "immediately after preparation" means immediately after the stirring of the dispersion is stopped, and "10 minutes later" means 10 minutes after the stirring of the dispersion is stopped. The following equipment was used for each measurement method. Ultrasonic measurement method: A modified ultrasound diagnostic device, "SONIMAGE HS1" (manufactured by Konica Minolta, Inc.), has been modified to allow observation of the power spectrum. Image analysis method: Automated flow-type particle image imaging analyzer "FPIA-3100" (manufactured by Sysmex Corporation) Laser analysis method: Laser diffraction particle size distribution analyzer "Mastersizer3000+" (manufactured by Malvern)

[0100] The measurement results are shown in Table II below. In each measurement method, the number of coarse particles at 0 minutes in the dispersion (CB1-1) with a stirring time of 100 minutes was set to 100, while all other values ​​were expressed as relative numbers.

[0101] [Table 2]

[0102] The number of coarse particles at 0 minutes and the number of coarse particles at 10 minutes were compared. The ultrasonic measurement method showed almost no difference in measurement results compared to the image analysis method and the laser analysis method, indicating that the measured values ​​hardly fluctuated with the time elapsed since stirring was stopped. Furthermore, because the measured values ​​hardly fluctuated with the time elapsed since stirring was stopped, it can be seen that the accuracy of the measurement is sufficiently high even immediately after stirring is stopped.

[0103] 2. Experiment 2 (Undiluted Solution) Carbon black dispersions (CB2-1) and (CB2-2) were prepared using the above-mentioned carbon black "Mogul® L" (manufactured by Cabot Corporation), and stirred. The stirring time for (CB2-1) was 100 minutes, and the stirring time for (CB2-2) was 200 minutes.

[0104] The number of coarse particles was measured in each dispersion immediately after stirring (0 minutes later) and 10 minutes later. The measurements were performed using three methods: the measurement method of this embodiment (ultrasonic measurement method), image analysis method, and laser analysis method. In the ultrasonic measurement method, the power spectrum was obtained using the method described above, and the number of coarse particles was calculated from an approximation formula between the obtained power spectrum and the number of coarse particles. Furthermore, "immediately after stirring" means immediately after the stirring of the dispersion is stopped, and "10 minutes later" means 10 minutes after the stirring of the dispersion is stopped. The above-mentioned apparatus was used in each measurement method.

[0105] The measurement results are shown in Table III below. In the ultrasonic measurement method, the number of coarse particles in the dispersion (CB2-1) at 0 minutes was set to 100, and all other values ​​were expressed as relative numbers. Furthermore, in the image analysis method and laser analysis method, the concentration of the dispersion used as a sample was too high, making it impossible to accurately measure the particle size and thus the number of coarse particles.

[0106] [Table 3]

[0107] Ultrasonic measurement methods demonstrate that the number of coarse particles can be measured even when the dispersion is at a relatively high concentration. [Explanation of symbols]

[0108] 1. Piezoelectric element 2 Ground electrode 3 Signal electrodes 4 Backing 5 reflective layer 6. Acoustic Matching Layer 6a First acoustic matching layer 6b Second acoustic matching layer 6c Third acoustic matching layer 6d Fourth acoustic matching layer 7 Signal electrical terminals 8 Acoustic Lenses 9. Middle Class 10 Ultrasonic probe 11 Main body 12 Connector section 13 Display section 14 Cables 15 Operation Input Section 16 Transmitter 17 Receiving Unit 18 Image generation unit 19 Image Processing Unit 20 DSC 21 Control Unit (Analysis Unit) 30 Dispersion 31 Flow channels 32 Liquid tank 33. Stirring blade W1 incident wave W2 reflected wave 100 Observation device

Claims

1. An observation method for observing coarse particles in a dispersion of particles in a liquid, A wave transmission step of transmitting ultrasonic waves to the dispersion liquid, A wave receiving step, in which the transmitted ultrasonic waves are received from the particles and the reflected waves generated are received. An image generation process that generates image data based on the received reflected wave, and An observation method comprising an analysis step of analyzing the coarse particles in the dispersion from the generated image data.

2. The observation method according to claim 1, wherein the particle size of the coarse particles is in the range of 0.01 to 1000 μm.

3. The observation method according to claim 1, wherein the particle size of the coarse particles is 10 times or more the target particle size of the dispersion in the dispersion.

4. In the image generation process described above, B-mode image data is generated, The observation method according to claim 1, wherein, in the analysis step, the coarse particles in the dispersion are analyzed from the generated B-mode image data.

5. In the image generation process described above, power spectral data is generated using the Doppler method. The observation method according to claim 1, wherein, in the analysis step, the coarse particles in the dispersion are analyzed from the power spectral data generated.

6. The observation method according to claim 4 or 5, wherein in the analysis step, the number of coarse particles in the dispersion is calculated from the generated image data.

7. The observation method according to claim 1, wherein the content of the particles in the dispersion is in the range of 0.0001 to 50% by mass relative to the total mass of the dispersion medium.

8. The observation method according to claim 1, wherein the coarse particles in the dispersion are observed while stirring.

9. An observation device for observing coarse particles in a dispersion in which particles are dispersed in a liquid, A wave transmitting unit that transmits ultrasonic waves to the dispersion liquid, A wave receiving unit that receives the reflected wave generated when the transmitted ultrasonic wave is reflected by the particle, An image generation unit that generates image data based on the received reflected wave, and An observation device having an analysis unit that analyzes the coarse particles in the dispersion from the generated image data.

10. A computer for an observation device comprising: a wave transmitting unit that transmits ultrasonic waves to a dispersion in which particles are dispersed in a liquid; a wave receiving unit that receives reflected waves generated when the transmitted ultrasonic waves are reflected by the particles; and an image generating unit that generates image data based on the received reflected waves, A program that functions as an analysis unit for analyzing coarse particles in the dispersion from the generated image data.

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