Method for detecting abnormalities in ultrasonic transducers

Abstract

The purpose of the present invention is to accurately detect an abnormality of an ultrasonic vibrator and reduce erroneous detection. To this end, an abnormality detection method for an ultrasonic vibrator in the present invention comprises: a first step for calculating the frequency characteristics of admittance of the ultrasonic vibrator; a second step for calculating, on the basis of the frequency characteristics of admittance obtained in the first step, a resonant frequency at which the admittance becomes the maximum value and a frequency width at the time of becoming a prescribed ratio value with respect to the maximum value; a third step for calculating sharpness on the basis of the resonant frequency and the frequency width obtained in the second step; and a fourth step for determining abnormality of the ultrasonic vibrator on the basis of the sharpness calculated in the third step.

Description

Technical Field

[0001] The present invention relates to a method for detecting abnormalities in ultrasonic transducers.

Background Art

[0002] When analyzing the components of a sample such as serum or urine, an ultrasonic transducer may be used as a stirring mechanism for mixing the sample and the reagent. The non-contact stirring technology using an ultrasonic transducer enables the avoidance of carry-over in which a medium such as a stirring rod is absent and the sample or reagent adhering to the medium affects the next analysis result. For such a stirring mechanism using an ultrasonic transducer, as with other mechanisms, it is necessary to confirm whether the operation is normal.

[0003] For example, Patent Document 1 discloses an electrical impedance spectrum measuring device for detecting the state of an ultrasonic transducer before executing its operation. In conventional technologies such as this Patent Document 1, the impedance of the ultrasonic transducer is measured, and the minimum value thereof, that is, the absolute value of the impedance at the resonance frequency, is compared with a threshold value to detect abnormalities in the ultrasonic transducer.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the threshold value used for detecting abnormalities at the minimum value of the impedance has a narrow settable range and is limited in reducing false detections. [[ID=4l]]<000003o> An object of the present invention is to accurately detect abnormalities in an ultrasonic transducer and reduce false detections.

Means for Solving the Problems

[0007] The method for detecting abnormalities in an ultrasonic transducer according to the present invention includes: a first step of calculating the frequency characteristics of the admittance of the ultrasonic transducer; a second step of calculating, based on the frequency characteristics of the admittance obtained in the first step, the resonance frequency at which the admittance reaches its maximum value and the frequency width at which it reaches a predetermined ratio to the maximum value; a third step of calculating the sharpness based on the resonance frequency and the frequency width obtained in the second step; and a fourth step of determining an abnormality in the ultrasonic transducer based on the sharpness calculated in the third step. [Effects of the Invention]

[0008] According to the present invention, it is possible to accurately detect abnormalities in ultrasonic transducers and reduce false detections. [Brief explanation of the drawing]

[0009] [Figure 1] Schematic diagram of an automated analyzer. [Figure 2] A diagram showing the configuration of the stirring mechanism and the power amplifier and impedance measurement circuit connected to it. [Figure 3] This graph shows the frequency characteristics of the impedance of a normal ultrasonic transducer, as measured by an impedance measurement circuit. [Figure 4] This graph shows the frequency characteristics of the admittance of a normal ultrasonic transducer, as calculated by the host computer. [Figure 5] This graph shows the frequency characteristics of the impedance of an abnormal ultrasonic transducer, as measured by an impedance measurement circuit. [Figure 6] This graph shows the frequency characteristics of the admittance of an abnormal ultrasonic transducer, as calculated by the host computer. [Figure 7] This graph shows the results of the host computer calculating the frequency characteristics of the admittance of a more abnormal ultrasonic transducer (compared to the case in Figure 6). [Figure 8]A flowchart illustrating the process for detecting anomalies in ultrasonic transducers. [Figure 9] Regarding Example 2, this graph shows the results of the host computer calculating the frequency characteristics of the admittance of an abnormal ultrasonic transducer. [Figure 10] This graph shows the results of the host computer calculating the admittance frequency characteristics of a normal ultrasonic transducer in Example 3. [Figure 11] A diagram illustrating the schematic configuration of the impedance measuring instrument in Example 4. [Modes for carrying out the invention]

[0010] Examples of the present invention are described below. [Examples]

[0011] Example 1 describes an example of an automated analyzer having a function to detect abnormalities in an ultrasonic transducer. Figure 1 is a schematic diagram of the automated analyzer. As shown in Figure 1, the automated analyzer includes a sample dispensing mechanism 104, a reagent dispensing mechanism 103, a reaction disk 106, a stirring mechanism 107, a light source 108, and an absorbance meter 109.

[0012] The sample dispensing mechanism 104 dispenses the sample from the sample container 101, which contains the sample to be analyzed, into the reaction vessel 105. The reagent dispensing mechanism 103 dispenses the reagent from the reagent bottle 102 (reagent container), which contains the reagent, into the reaction vessel 105. The reaction disk 106 is rotatable, and the reaction vessel 105 is arranged circumferentially on its upper surface. The stirring mechanism 107 stirs the mixture of sample and reagent (reaction solution) dispensed into the reaction vessel 105 without contact. The light source 108 irradiates light onto the mixture, whose reaction has been accelerated by stirring. The absorbance meter 109 measures the absorbance characteristics of the mixture.

[0013] After the absorbance characteristic measurement is complete, the reaction vessel 105 is cleaned by a washing mechanism (not shown) and reused for the next reaction. Furthermore, the probes of the sample dispensing mechanism 104 and the reagent dispensing mechanism 103 are cleaned by a washing tank (not shown).

[0014] Although omitted in FIG. 1, the automatic analyzer also includes a host computer. The host computer exchanges signals with the specimen dispensing mechanism 104, the reagent dispensing mechanism 103, the reaction disk 106, the stirring mechanism 107, etc., and controls each operation. The host computer includes an arithmetic means for performing calculations, a storage means for storing information, and a communication means for transmitting and receiving information. The arithmetic means is, for example, a processor, the storage means is, for example, a semiconductor memory or a magnetic disk device, and the communication means is, for example, a network interface. Further, the host computer may include a keyboard and a mouse as input means for inputting information, and a display device and a printer as output means for outputting information.

[0015] FIG. 2 is a diagram showing the configuration of the stirring mechanism and the power amplifier and impedance measurement circuit connected thereto. Among FIG. 2, the cross section of the stirring mechanism shows a cross section parallel to the radial direction and the vertical direction of the reaction disk 106 including the stirring mechanism 107 in FIG. 1. On the other hand, the part connected to the host computer side with respect to the stirring mechanism in FIG. 2 shows a schematic electric circuit.

[0016] The reaction disk 106 has a thermostat 110 that holds the thermostatic water 111 at a specified temperature. The thermostatic water 111 circulating in the thermostat 110 contacts the reaction vessel 105, so that the reaction vessel 105 is maintained at a predetermined temperature. The stirring mechanism 107 stirs the mixed solution non-contact by irradiating the reaction vessel 105 with sound waves. In this embodiment, although thermostatic water is used as the liquid for mediating the sound waves, water other than thermostatic water may be used, or a liquid other than water may be used.

[0017] The stirring mechanism 107 includes an ultrasonic vibrator 201 (piezoelectric element) that generates ultrasonic waves, a divided electrode 208 (a plurality of electrodes) provided on the surface of the ultrasonic vibrator 201, and a connector 207 that electrically connects the divided electrode 208 and the power amplifier 202, etc.

[0018] The ultrasonic transducer 201 is positioned so that one side (air side) is in contact with the air and the other side (constant temperature water side) is in contact with the constant temperature water 111. The divided electrode 208 is positioned on the air side. The divided electrode 208 is divided into multiple electrodes at different height positions, as shown by the dashed frame in Figure 2. In this embodiment, 14 divided electrodes 208 are provided (only some of the divided electrodes are shown in Figure 2), but the number of divided electrodes 208 is not limited to 14. The dimensions and shape of each divided electrode 208 can be individually and arbitrarily designed, but in this embodiment, the 1st to 13th divided electrodes 208 from the top are all the same shape, and only the 14th (bottommost) divided electrode 208 is formed to be slightly longer than the other divided electrodes. Each divided electrode 208 is connected one-to-one to each pin on one end of the connector 207. The other end of the connector 207 is connected to the power amplifier 202 or the impedance measurement circuit 209 via the relay group 203.

[0019] The power amplifier 202 drives the ultrasonic transducer 201 by applying voltage to each electrode, thereby generating ultrasonic waves. The power amplifier 202 is equipped with a first communication unit 205, and the host computer controls the power amplifier 202 via this first communication unit 205.

[0020] The relay group 203 has multiple switches, and the opening and closing of each switch is controlled by commands from the host computer. In other words, the relay group 203 functions as a switch to switch the connection between the power amplifier 202 and each divided electrode 208. For example, the host computer selects one or more divided electrodes 208 at an appropriate position according to the liquid level of the mixed liquid in the reaction vessel 105, and controls the relay group 203 to apply a voltage to the selected divided electrodes 208. This adjusts the position where ultrasound is irradiated onto the reaction vessel 105.

[0021] Furthermore, the relay group 203 also has a switch that, based on a command from the host computer, switches between connecting the ultrasonic transducer 201 to the power amplifier 202 or connecting the ultrasonic transducer 201 to the impedance measurement circuit 209. In other words, the relay group 203 connects the power amplifier 202 to the ultrasonic transducer 201 during stirring, and connects the impedance measurement circuit 209 to the ultrasonic transducer 201 during impedance measurement.

[0022] The impedance measurement circuit 209 measures the frequency characteristics of the impedance of the ultrasonic transducer 201. The frequency characteristics of the impedance of the ultrasonic transducer 201 are represented, for example, by the sum of the frequency characteristics of the impedances related to each divided electrode 208. Similarly, the impedance measurement circuit 209 is provided with a second communication unit 206, and the host computer controls the impedance measurement circuit 209 via this second communication unit 206. The impedance measurement circuit 209 also transmits the measurement results of the impedance frequency characteristics to the host computer via the second communication unit 206. Note that the impedance measurement circuit 209 does not need to be configured independently of the host computer, as shown in Figure 2; it may be integrated into the host computer.

[0023] Upon receiving the frequency characteristics of the impedance of the ultrasonic transducer 201 from the impedance measurement circuit 209, the host computer detects whether the ultrasonic transducer 201 is functioning normally or abnormally by performing the following calculations.

[0024] Figure 3 is a graph showing the frequency characteristics of the impedance of a normal ultrasonic transducer measured by an impedance measurement circuit. Figure 3 plots the waveform 301 of the measured absolute value of the impedance, with the horizontal axis representing the driving frequency and the vertical axis representing the impedance. The frequency at which the absolute value of the impedance is minimum 302 is the resonant frequency 303 of this ultrasonic transducer. At this frequency, the ultrasonic transducer is considered to be vibrating more strongly than when driven at other frequencies.

[0025] Figure 4 is a graph showing the frequency characteristics of the admittance of a normal ultrasonic transducer calculated by the host computer. The calculated admittance waveform 401 is plotted in Figure 4, with the horizontal axis representing the driving frequency and the vertical axis representing the admittance. The frequency at which the admittance reaches its maximum value 402 is the resonant frequency 403 of this ultrasonic transducer. The admittance of the ultrasonic transducer is calculated by the host computer by normalizing (dividing by the characteristic impedance) the impedance measured by the impedance measurement circuit 209, and then taking its reciprocal.

[0026] The frequency width 404 of the waveform 401 shown in Figure 4 is the frequency width at which the frequency becomes a predetermined ratio value 405, obtained by multiplying the maximum value 402 by a predetermined ratio. Here, the predetermined ratio is set to a value smaller than 1 / √2. The sharpness Q' of the waveform 401 is calculated as resonant frequency 403 / frequency width 404. In the case of a normal ultrasonic transducer waveform, if the predetermined ratio is set to, for example, 0.3 times, the sharpness Q' will be approximately 30 to 230.

[0027] In this specification, the sharpness Q' is defined as the value calculated based on the frequency bandwidth when it is less than 1 / √2 times the maximum value, and is distinguished from the Q value, which is calculated based on the frequency bandwidth (full width at half maximum) when it is 1 / √2 times the maximum value.

[0028] Figure 5 is a graph showing the frequency characteristics of the impedance of an abnormal ultrasonic transducer measured by an impedance measurement circuit. In Figure 5, the waveform 501 of the measured absolute value of the impedance is plotted, with the horizontal axis representing the driving frequency and the vertical axis representing the impedance. The frequency at which the absolute value of the impedance is at its minimum value 502 is the resonant frequency 503 of this ultrasonic transducer.

[0029] The minimum impedance value 502 in waveform 501 is higher than the minimum impedance value 302 in waveform 301, indicating that current is less likely to flow. In other words, an ultrasonic transducer that produces a measurement result like waveform 501 has reduced piezoelectricity (ultrasonic irradiation intensity) compared to an ultrasonic transducer that produces a measurement result like waveform 301, and can be considered abnormal. For this reason, it is possible to some extent to determine whether an ultrasonic transducer is abnormal or not by comparing the minimum impedance value with a predetermined threshold. However, the threshold value that can be set when judging by the minimum impedance value has a narrow range, and there are limits to reducing misjudgments. For example, if the threshold is reduced in order to reduce cases where an abnormal ultrasonic vibrator is misjudged as normal, a certain number of cases where a normal ultrasonic transducer is misjudged as abnormal will occur.

[0030] Figure 6 is a graph showing the frequency characteristics of the admittance of an abnormal ultrasonic transducer calculated by the host computer. In Figure 6, the calculated admittance waveform 601 is plotted, with the horizontal axis representing the driving frequency and the vertical axis representing the admittance. The frequency at which the admittance reaches its maximum value 602 is the resonant frequency 603 of this ultrasonic transducer.

[0031] The frequency width 604 of the waveform 601 shown in Figure 6 is the frequency width at which the value becomes a predetermined ratio 605, obtained by multiplying the maximum value 602 by a predetermined ratio. The sharpness Q' of the waveform 601 is calculated as resonant frequency 603 / frequency width 604. In the case of an abnormal ultrasonic transducer waveform, if the predetermined ratio is set to, for example, 0.3 times, the sharpness Q' cannot be calculated for more than 90% of ultrasonic transducers, and although it can be calculated for less than 10% of ultrasonic transducers, the sharpness Q' will be at most around 30.

[0032] In this way, more accurate anomaly detection is possible than using the Q value calculated based on the anomaly itself. For example, according to the determination method of this embodiment using the sharpness Q', it is possible to determine that a waveform in which only the vicinity of the peak (near the resonant frequency) is sharp is an anomaly, as shown in Figure 6.

[0033] Here, we will explain a specific example of how to compare sharpness Q' with a threshold.

[0034] The first example is a statistical comparison method. In this method, sharpness Q' values ​​are first collected from a large number of normal ultrasonic transducers, and a statistical population of sharpness Q' is constructed. Next, a normal range (threshold) is defined based on the standard deviation σ, centered around the mean of the population. For example, a value of -3σ or higher on average is defined as the normal range. The host computer then calculates the sharpness Q' of the ultrasonic transducer to be evaluated and compares the calculated result with the predefined normal range. If the calculated result is within the normal range, the ultrasonic transducer is judged to be normal; if the calculated result is outside the normal range, the ultrasonic transducer is judged to be abnormal.

[0035] The second example is a comparison method using machine learning. In this method, a trained model is first built by using the sharpness Q' obtained from a large number of normal ultrasonic transducers as training data. Then, the host computer calculates the sharpness Q' of the ultrasonic transducer to be judged, inputs the calculation result into the trained model, and outputs whether or not it deviates from the normal sharpness Q' range (threshold).

[0036] In addition, in both of the comparison methods described above, the pre-set normal range (threshold) may differ for each type of ultrasonic transducer. For example, the sharpness Q' data collected in advance may be distinguished depending on whether the ultrasonic transducer material is lead-containing PZT (lead zirconate titanate) or lead-free LN (lithium niobate).

[0037] Furthermore, anomaly detection may be performed not only using the sharpness Q', but also by combining one or more other features obtained during the calculation of sharpness Q', such as resonant frequency, phase, absolute value of admittance, absolute value of impedance, etc., through multivariate analysis. Using multivariate analysis enables more accurate anomaly detection.

[0038] Next, we will explain a method for detecting abnormalities in cases where the degree of abnormality in the ultrasonic transducer is even higher, and the sharpness Q' itself is difficult to calculate.

[0039] Figure 7 is a graph showing the frequency characteristics of the admittance of a more abnormal ultrasonic transducer calculated by the host computer (compared to the case in Figure 6). In Figure 7, the calculated admittance waveform 701 is plotted, with the horizontal axis representing the driving frequency and the vertical axis representing the admittance. The frequency at which the admittance reaches its maximum value 702 is the resonant frequency 703 of this ultrasonic transducer.

[0040] In the waveform 701 shown in Figure 7, there is no frequency at which the predetermined ratio value 704 is obtained by multiplying the maximum value 702 by a predetermined ratio. Therefore, the frequency width cannot be calculated, and consequently, the sharpness Q' cannot be calculated either. Consequently, the aforementioned anomaly detection method using the sharpness Q' cannot be applied.

[0041] If the sharpness Q' cannot be calculated, it is likely because the vibration does not change significantly between the resonant frequency 703 and other frequencies, and the admittance frequency characteristics do not contain sharp resonant components. The absence of sharp resonant components means that the piezoelectricity (ultrasonic irradiation intensity) is reduced. For example, if the frequency width is calculated for the waveform 701 shown in Figure 7 based on a predetermined ratio value greater than 1 / √2 times the maximum value 702, the resulting sharpness Q'' will be lower than the sharpness Q'' obtained using the same method for a normal ultrasonic transducer waveform (for example, the waveform 401 shown in Figure 4). In other words, if the sharpness Q' cannot be calculated, as with the waveform 701 shown in Figure 7, it is possible to consider the ultrasonic transducer to be abnormal.

[0042] Figure 8 is a flowchart showing the flow of anomaly detection in an ultrasonic transducer.

[0043] First, the impedance measurement circuit 209, based on control from the host computer, applies a voltage to the electrodes of the ultrasonic transducer that has been frequency-swept within the range of 1,500 MHz to 1,700 MHz. At this time, the impedance measurement circuit 209 calculates the impedance, which is the ratio of the voltage to the measured current, and obtains the frequency characteristics of the impedance of the ultrasonic transducer (step S801), and transmits it to the host computer.

[0044] Next, the host computer obtains the admittance frequency characteristics of the ultrasonic transducer by calculating the admittance, which is the reciprocal of the impedance, based on the frequency characteristics of the received impedance (step S802).

[0045] Subsequently, the host computer calculates the resonant frequency at which the admittance is at its maximum value based on the acquired admittance frequency characteristics, and also calculates the frequency width at which the maximum value is multiplied by a predetermined ratio less than 1 / √2 times. Furthermore, the host computer calculates the sharpness Q' by dividing the resonant frequency by the frequency width (step S803).

[0046] At this point, the host computer determines whether or not it was possible to calculate the sharpness Q' in step S803 (step S804). If it is determined that it is not possible to calculate it, the host computer outputs "abnormal" as the detection result for the ultrasonic transducer (step S807).

[0047] In step S804, if it is determined that calculation is possible, the host computer determines whether the sharpness Q' is within the normal range (step S805). If it is determined that it is outside the normal range, the host computer outputs "abnormal" as the detection result for the ultrasonic transducer (step S807).

[0048] In step S805, if it is determined that the result is within the normal range, the host computer outputs "Normal" as the detection result of the ultrasonic transducer (step S806). [Examples]

[0049] Example 2 is an example of an automated analyzer that has the function of detecting abnormalities in an ultrasonic transducer by calculating multiple sharpness Q' values ​​from the same waveform and comparing each of them with a threshold value.

[0050] Figure 9 is a graph showing the frequency characteristics of the abnormal ultrasonic transducer's admittance calculated by the host computer for Example 2. In Figure 9, the calculated admittance waveform 901 is plotted, with the horizontal axis representing the driving frequency and the vertical axis representing the admittance. The frequency at which the admittance reaches its maximum value 902 is the resonant frequency 903 of this ultrasonic transducer. Note that waveform 901 shown in Figure 9 is the same as waveform 601 shown in Figure 6, but for convenience, the signs of the maximum value and resonant frequency are different in Figure 9 and Figure 6.

[0051] In this embodiment, an attempt is made to calculate the frequency width of waveform 901 as follows: a first frequency width when it is 0.20 times the maximum value 902, a second frequency width when it is 0.40 times the maximum value 902, and a third frequency width when it is 0.60 times the maximum value 902. For the first frequency width, calculation is impossible because the frequency at which the predetermined ratio value 904 is 0.20 times the maximum value 902 does not exist on the side smaller than the resonant frequency. For the second frequency width, the frequency at which the predetermined ratio value 906 is 0.40 times the maximum value 902 exists on both sides of the resonant frequency, so it is calculated as frequency width 905. For the third frequency width, the frequency at which the predetermined ratio value 908 is 0.60 times the maximum value 902 exists on both sides of the resonant frequency, so it is calculated as frequency width 907.

[0052] Next, an attempt is made to calculate the sharpness Q' for each frequency bandwidth. The sharpness Q' corresponding to the first frequency bandwidth cannot be calculated because the first frequency bandwidth itself could not be calculated. The sharpness Q' corresponding to the second frequency bandwidth is calculated using the resonant frequency 903 / frequency bandwidth 905. Furthermore, the sharpness Q' corresponding to the third frequency bandwidth is calculated using the resonant frequency 903 / frequency bandwidth 907.

[0053] Subsequently, each sharpness level Q' is compared with a threshold value. Here, it is possible to set a different threshold value for each sharpness level Q'. The method for comparing the sharpness level Q' with the threshold value is the same as in Example 1 described above. As an example of the comparison results, at a predetermined ratio value 904 which is 0.20 times the maximum value, the sharpness level Q' itself cannot be calculated; at a predetermined ratio value 906 which is 0.40 times the maximum value, the sharpness level Q' is outside the normal range; and at a predetermined ratio value 908 which is 0.60 times the maximum value, the sharpness level Q' is within the normal range.

[0054] Thus, the comparison result between the sharpness Q' and the threshold differs depending on the ratio used to multiply the maximum admittance value. This is because abnormal ultrasonic transducers have higher impedance near the resonance point and lower impedance near the anti-resonance point compared to normal ultrasonic transducers, so when the admittance waveform is expressed, it tends to have a flattened shape with a high minimum value. Therefore, if the admittance value (the ratio multiplied by the maximum value) set to calculate the frequency bandwidth is low, it tends to fall outside the normal range, and if it is high, it tends to fall within the normal range. In this embodiment, by calculating multiple sharpness Q' values ​​from the same waveform and comparing each with the threshold, it becomes possible not only to detect the abnormality of the ultrasonic transducer itself, but also to accurately detect the degree of the abnormality. Furthermore, by accumulating the data of each calculated sharpness Q' and checking the changes over time, it becomes easier to grasp signs of abnormality or failure of the ultrasonic transducer compared to Embodiment 1.

[0055] In this embodiment, we attempted to calculate the sharpness Q' based on frequency widths that are 0.20, 0.40, and 0.60 times the maximum admittance value, but the ratio multiplied by the maximum value is not limited to these. Also, in this embodiment, we explained the case where we attempted to calculate three sharpness Q' values ​​from the same waveform, but the number of sharpness Q' values ​​to be calculated is not limited to three. [Examples]

[0056] Example 3 describes an example of an automated analyzer that has a function to calculate multiple sharpness values ​​Q' from the same waveform and detect abnormalities in an ultrasonic transducer based on the ratio of each sharpness value Q'.

[0057] Figure 10 is a graph showing the frequency characteristics of the admittance of a normal ultrasonic transducer calculated by the host computer for Example 3. Figure 10 plots the calculated admittance waveform 1001, with the horizontal axis representing the driving frequency and the vertical axis representing the admittance. The frequency at which the admittance reaches its maximum value 1002 is the resonant frequency 1003 of this ultrasonic transducer. Note that the waveform 1001 shown in Figure 10 is the same as the waveform 401 shown in Figure 4, but for convenience, the signs of the maximum value and resonant frequency are different in Figure 10 and Figure 4.

[0058] In this embodiment, an attempt is made to calculate the frequency width of waveform 1001 as follows: a first frequency width when it is 0.40 times the maximum value 1002, a second frequency width when it is 0.50 times the maximum value 1002, and a third frequency width when it is 0.60 times the maximum value 1002. For the first frequency width, since the frequency at which the predetermined ratio value 1005, which is 0.40 times the maximum value 1002, exists on both sides of the resonance frequency, it is calculated as frequency width 1004. For the second frequency bandwidth, the frequency at which the predetermined ratio value of 1007 (0.50 times the maximum value of 1002) exists on both sides of the resonant frequency, and is therefore calculated as a frequency bandwidth of 1006. For the third frequency bandwidth, the frequency at which the predetermined ratio value of 1009 (0.60 times the maximum value of 1002) exists on both sides of the resonant frequency, and is therefore calculated as a frequency bandwidth of 1008.

[0059] Next, the sharpness is calculated for each frequency bandwidth. The sharpness Q' corresponding to the first frequency bandwidth is calculated using the resonant frequency 1003 / frequency bandwidth 1004. The sharpness Q' corresponding to the second frequency bandwidth is calculated using the resonant frequency 1003 / frequency bandwidth 1006. Furthermore, the sharpness Q' corresponding to the third frequency bandwidth is calculated using the resonant frequency 1003 / frequency bandwidth 1008.

[0060] Subsequently, the ratio of each sharpness Q' is calculated, and based on the calculated ratio, it is detected whether the ultrasonic transducer is normal or abnormal. For example, in the case of Figure 10, the ratio of sharpness Q' calculated based on frequency widths that are 0.40, 0.50, and 0.60 times the maximum admittance is approximately 1:1.3:1.6. This is because a normal ultrasonic transducer yields sharp resonance characteristics, and the sharpness Q' calculated based on a frequency width 1004 that is 0.40 times the maximum admittance (a predetermined ratio value of 1005) is also relatively high. Therefore, in a normal ultrasonic transducer, even if the ratio multiplied by the maximum value is changed, there will be no significant difference in the ratio of each sharpness Q'. On the other hand, in abnormal ultrasonic transducers, the sharpness of the waveform decreases, so the smaller the ratio multiplied by the maximum value, the more significantly the sharpness Q' tends to decrease. For example, in the case of abnormal ultrasonic transducer waveforms as shown in Figures 6 and 9, the ratio of sharpness Q' calculated based on frequency widths that are 0.40, 0.50, and 0.60 times the maximum admittance value is approximately 1:2.3:5.1. [Examples]

[0061] In the embodiments described above, the frequency characteristics of the impedance were measured using an impedance measurement circuit 209 built into the automatic analyzer. However, in Embodiment 4, the frequency characteristics of the impedance are measured using an impedance measuring instrument attached to the automatic analyzer. The impedance measuring instrument in Embodiment 4 is attached to the stirring mechanism 107 of the automatic analyzer by a service worker or the like during maintenance of the ultrasonic transducer. Specifically, the impedance measuring instrument is attached to the other end of the connector 207, one end of which is connected to each divided electrode 208, by replacing the power amplifier 202 system.

[0062] Figure 11 is a schematic diagram of the configuration of the impedance meter according to Embodiment 4. As shown in Figure 11, the impedance meter comprises a portable case 1101, an impedance measurement circuit 209, an ultrasonic transducer-side connection cable 1102, and a host computer-side connection cable 1103. The portable case 1101 houses the impedance measurement circuit 209. The impedance measurement circuit 209 measures the frequency characteristics of the impedance of the ultrasonic transducer 201. The ultrasonic transducer-side connection cable 1102 electrically connects the impedance measurement circuit 209 to the divided electrodes 208 of the ultrasonic transducer to be measured via a connector 207. The cable end 1104 of the ultrasonic transducer-side connection cable 1102 can have any configuration as long as it can be electrically connected to the divided electrodes 208 of the ultrasonic transducer. The host computer-side connection cable 1103 connects the impedance measurement circuit 209 to the host computer.

[0063] The impedance measurement circuit 209 transmits the frequency characteristics of the impedance measured via the ultrasonic transducer-side connection cable 1102 to the host computer via the host computer-side connection cable 1103. Note that wireless communication may be used instead of the wired host computer-side connection cable 1103 for the connection between the impedance measurement circuit 209 and the host computer. The host computer performs abnormality detection of the ultrasonic transducer in the same manner as in the embodiments described above.

[0064] The host computer can have the same configuration as in the embodiments described above, but it does not necessarily have to be mounted on the automated analyzer and may be provided separately. Furthermore, some or all of the host computer's calculation functions may be mounted on the impedance meter, allowing the impedance meter to not only measure the frequency characteristics of the impedance but also to detect anomalies in the ultrasonic vibration element. In this case, the impedance meter may also be equipped with input and output means and can be considered an anomaly detector.

[0065] The present invention is not limited to the embodiments described above, and various modifications are included. For example, although the embodiments described above described an ultrasonic transducer provided in a stirring mechanism, the ultrasonic transducer of the cleaning mechanism can be similarly configured when an ultrasonic transducer is used in a cleaning mechanism. In this case, the preset threshold and the data collected for setting the threshold may differ depending on whether the ultrasonic transducer is applied to a stirring mechanism or a cleaning mechanism. [Explanation of Symbols]

[0066] 101...Sample container, 102...Reagent bottle, 103...Reagent dispensing mechanism, 104...Sample dispensing mechanism, 105...Reaction vessel, 106...Reaction disk, 107...Stirring mechanism, 108...Light source, 109...Absorbance meter, 110...Constant temperature bath, 111...Constant temperature water, 201...Ultrasonic transducer, 202...Power amplifier, 203...Relay group, 205...First communication unit, 206...Second communication unit, 207...Connector, 208...Divided electrode, 209...Impedance measurement circuit, 301...Waveform, 302...Minimum value, 303...Resonant frequency, 401...Waveform, 402...Maximum value, 403...Resonant frequency, 404...Frequency width, 405...Determined ratio value, 501...Waveform 502...Minimum value, 503...Resonant frequency, 601...Waveform, 602...Maximum value, 603...Resonant frequency, 604...Frequency width, 605...Determined ratio value, 701...Waveform, 702...Maximum value, 703...Resonant frequency, 704...Determined ratio value, 901...Waveform, 902...Maximum value, 903...Resonant frequency, 904...Determined ratio value, 905...Frequency width, 906...Determined ratio value, 907...Frequency width, 908...Determined ratio value, 1001...Waveform, 1002...Maximum value, 1003...Resonant frequency, 1004...Frequency width, 1005...Determined ratio value, 1006...Frequency width, 1007...Determined ratio value, 1008...Frequency width, 1009...Determined ratio value.

Claims

1. In a method for detecting abnormalities in an ultrasonic transducer, The first step is to calculate the frequency characteristics of the admittance of the ultrasonic transducer, A second step involves calculating, based on the frequency characteristics of the admittance obtained in the first step, the resonant frequency at which the admittance reaches its maximum value and the frequency width at which it reaches a predetermined ratio to the maximum value. A third step is to calculate the sharpness based on the resonance frequency and frequency width obtained in the second step, A fourth step in which an abnormality in the ultrasonic transducer is determined based on the sharpness calculated in the third step, A method for detecting abnormalities in an ultrasonic transducer, characterized by including the following:

2. In claim 1, A method for detecting abnormalities in an ultrasonic transducer, characterized in that the ratio is less than 1 / √2 times.

3. In claim 1, The first step described above is: The steps include applying a voltage to the electrodes of an ultrasonic transducer that has been frequency-swept in the range of 1,500 MHz to 1,700 MHz, The steps include: calculating the impedance, which is the ratio of the voltage to the measured current; A step of calculating admittance, which is the reciprocal of the impedance, A method for detecting abnormalities in an ultrasonic transducer, characterized by including the following:

4. In claim 1, A method for detecting abnormalities in an ultrasonic transducer, characterized in that if the sharpness cannot be calculated in the third step, and if the sharpness calculated in the third step is smaller than a threshold, the ultrasonic transducer is determined to be abnormal.

5. In claim 1, In the second step, a plurality of frequency widths with different ratios are calculated, In the third step described above, the sharpness is calculated for each of the multiple frequency widths, The fourth step is to compare each sharpness with a threshold and determine an abnormality in the ultrasonic transducer based on the comparison results, characterized in that an abnormality in the ultrasonic transducer is detected.

6. A dispensing mechanism for dispensing samples or reagents into a reaction vessel, A stirring mechanism for stirring the sample and reagent in the reaction vessel, The system includes a cleaning mechanism for cleaning the dispensing mechanism, In an automatic analyzer having an ultrasonic transducer for the stirring mechanism or the cleaning mechanism, An automated analyzer that performs the ultrasonic transducer abnormality detection method described in claim 1.

7. An abnormality detector connected to the electrodes of an ultrasonic transducer to detect abnormalities in an ultrasonic vibrating element, wherein the abnormality detector performs the ultrasonic transducer abnormality detection method described in claim 1.

8. A measuring instrument connected to the electrodes of an ultrasonic transducer to measure the frequency characteristics of the impedance of the ultrasonic transducer, A computer that performs the ultrasonic transducer abnormality detection method according to claim 1 based on the impedance frequency characteristics transmitted from the measuring instrument, An ultrasonic transducer anomaly detection system equipped with this system.

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