Automatic analysis apparatus, diagnosis system, and diagnosis method

Abstract

Provided is an automatic analysis apparatus which comprises: an ultrasonic vibrator including a piezoelectric body and an electrode attached to the piezoelectric body; and a control device that performs failure diagnosis on the ultrasonic vibrator. The control device defines and stores a normal range of electrical impedance unique to the ultrasonic vibrator, on the basis of a measured value of electrical impedance obtained by applying a voltage to the electrode, compares, with the normal range and during diagnosis, the measured value of the electrical impedance obtained by applying the voltage to the electrode, and performs failure diagnosis on the ultrasonic vibrator.

Description

Automated analyzer, diagnostic system, and diagnostic method

[0001] The present invention relates to an automatic analyzer equipped with an ultrasonic transducer, and a diagnostic system and method for diagnosing whether the ultrasonic transducer of the automatic analyzer is normal or abnormal.

[0002] In automated analyzers, the sample and reagent are dispensed into a reaction cell, stirred, and reacted, and the specific components contained in the sample are quantitatively analyzed based on the absorbance of the liquid after the reaction. The sample and reagent can be stirred by directly stirring the liquid in the reaction cell with a stirring rod, or by a non-contact method using ultrasound. Non-contact stirring using ultrasound is useful for avoiding contamination between the sample and reagent, and is adopted in some automated analyzers. However, failure of the ultrasonic vibrator that generates the ultrasound directly leads to a decrease in the accuracy and reproducibility of the component analysis.

[0003] In response to this, Patent Document 1 discloses a method for diagnosing a failure in an ultrasonic transducer from the electrical impedance spectrum of the ultrasonic transducer.

[0004] Japanese Patent Application Laid-Open No. 2022-177414

[0005] In Patent Document 1, a normal population is generated in advance from a large number of normal ultrasonic transducers with respect to electrical impedance, and a fault diagnosis of the ultrasonic transducer is performed by comparing a normal range defined from the normal population with the measured value at the time of diagnosis.

[0006] The measured electrical impedance of an ultrasonic transducer in an automated analyzer can fluctuate due to factors other than malfunction. For example, even between corresponding ultrasonic transducers in the same automated analyzer, the measured electrical impedance can vary depending on the length of the wiring connected to the electrodes, the wiring routing, and individual differences in the ultrasonic transducer. Conventionally, including the technology of Patent Document 1, a normal range was defined for each electrode of an ultrasonic transducer based on a large amount of data obtained from multiple automated analyzers, and this normal range was used to diagnose faults in ultrasonic transducers in multiple managed automated analyzers. However, this normal range was a statistically derived value without considering the influence of various factors that affect the measured electrical impedance, such as wiring length, as described above. Therefore, the inventors of the present application have found that, based on their investigations, some automated analyzers may diagnose a normal ultrasonic transducer as abnormal, indicating that there is room for improvement in diagnostic accuracy. When a normal ultrasonic transducer is determined to be abnormal, unnecessary replacement of the ultrasonic transducer is performed, which can reduce the operating rate of the automated analyzer and increase the labor hours and parts costs required for the replacement unnecessarily.

[0007] An object of the present invention is to provide an automatic analyzer, a diagnostic system, and a diagnostic method that can improve the reliability of fault diagnosis of ultrasonic transducers.

[0008] In order to achieve the above object, the present invention provides an automatic analyzer comprising an ultrasonic vibrator including a piezoelectric body and electrodes attached to the piezoelectric body, and a control device that performs fault diagnosis of the ultrasonic vibrator, wherein the control device defines and stores a normal range of electrical impedance specific to the ultrasonic vibrator based on measured values ​​of electrical impedance obtained by applying a voltage to the electrodes, and compares the measured values ​​of electrical impedance obtained by applying a voltage to the electrodes during diagnosis with the normal range, thereby providing an automatic analyzer that performs fault diagnosis of the ultrasonic vibrator.

[0009] According to the present invention, it is possible to improve the reliability of fault diagnosis of an ultrasonic transducer in an automatic analyzer.

[0010] FIG. 1 is a schematic diagram of a diagnostic system according to one embodiment of the present invention. FIG. 2 is a schematic diagram showing a cross section of an ultrasonic stirring mechanism provided in an automatic analyzer according to one embodiment of the present invention, together with its drive system. FIG. 3 is a diagram explaining the difference in electrical impedance spectra between a normal ultrasonic transducer and a faulty ultrasonic transducer. FIG. 4 is an explanatory diagram of a normal range used in fault diagnosis of an ultrasonic transducer according to one embodiment of the present invention. FIG. 5 is an explanatory diagram of fault diagnosis of an ultrasonic transducer using the normal range according to one embodiment of the present invention. FIG. 6 is a diagram explaining the definition of the normal range of the electrical impedance of an ultrasonic transducer and the timing for performing diagnosis of the ultrasonic transducer according to one embodiment of the present invention. FIG. 7 is a flowchart showing an example of a series of processing procedures of a control device relating to the definition of the normal range according to one embodiment of the present invention. FIG. 8 is a flowchart showing an example of a series of processing procedures of a control device relating to fault diagnosis of an ultrasonic transducer according to one embodiment of the present invention. FIG. 9 is an example of a diagnosis result of an ultrasonic transducer output by a control device to a display unit according to one embodiment of the present invention. FIG. 10 is an explanatory diagram of a normal range used in fault diagnosis of an ultrasonic transducer in a modified example.

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following describes embodiments of the present invention with reference to the accompanying drawings. In the following description, the same or corresponding elements in each drawing are designated by the same reference numerals, and redundant description will be omitted where appropriate.

[0012] (Diagnostic System) FIG. 1 is a schematic diagram of a diagnostic system according to one embodiment of the present invention. The diagnostic system 100 shown in FIG. 1 includes a control device 116 that performs fault diagnosis on an ultrasonic transducer 203 ( FIG. 2 ) provided in an automatic analyzer 101. The control device 116 is a computer including a calculation device such as a CPU and storage devices such as RAM, ROM, a hard disk drive (HHD), and an SSD. FIG. 1 illustrates an example of a configuration in which the control device 116 is provided in the automatic analyzer 101. That is, in this embodiment, the computer provided in the automatic analyzer 101 also serves as the control device 116 of the diagnostic system 100, in other words, the control device 116 having a diagnostic function for the ultrasonic transducer 203 ( FIG. 2 ). However, the control device 116 of the diagnostic system 100 may also be a computer (such as a server) connected to the automatic analyzer 101 via a network such as a LAN or the Internet.

[0013] (Configuration of the automatic analyzer) The automatic analyzer 101 illustrated in FIG. 1 includes a sample transport line 105, a reaction disk 110, a reagent disk 107, a sample dispensing mechanism 104, a reagent dispensing mechanism 108, an ultrasonic stirring mechanism 114, a light source 111, an absorbance meter 112, a cleaning mechanism 118, a drive circuit 115, a selection unit 117, an input unit 119, a display unit 120, and a control device 116.

[0014] The sample transport line 105 is a device that moves the sample rack 103 to the sample dispensing mechanism 104. A plurality of sample cups 102 are placed on the sample rack 103. Each sample cup 102 contains a sample to be analyzed, such as blood or urine.

[0015] A plurality of reaction cells 109 are arranged circumferentially on the reaction disk 110 to form a ring. A specimen and a reagent are dispensed into each reaction cell 109. A plurality of reagent bottles 106 are installed on the reagent disk 107. The reagent bottles 106 contain reagents to be mixed with the specimen. The specimen dispensing mechanism 104 dispenses the specimen from the sample cup 102 into the reaction cells 109 on the reaction disk 110. The reagent dispensing mechanism 108 dispenses the reagent from the reagent bottles 106 on the reagent disk 107 into the same reaction cells 109 on the reaction disk 110. The ultrasonic stirring mechanism 114 uses ultrasonic waves 113 to stir the mixture of the specimen and the reagent dispensed into the reaction cells 109, promoting the reaction between the specimen and the reagent. The mixture of the specimen and the reagent is also called a reaction liquid.

[0016] A light source 111 irradiates the reaction cell 109 with light. An absorption spectrometer 112 measures the absorbance of the light that has passed through the reaction solution inside the reaction cell 109. The measured absorbance is input to a control device 116, which then quantitatively analyzes specific components contained in the sample. A cleaning mechanism 118 cleans the reaction cell 109 after the sample analysis has been completed.

[0017] The drive circuit 115 applies a voltage to the ultrasonic agitation mechanism 114 to radiate ultrasonic waves 113. The selection unit 117 selectively switches the circuit connection of the ultrasonic agitation mechanism 114 to the drive circuit 115 or the control device 116. The input unit 119 is an external interface, and an operator such as a user can access the control device 116 by operating the input unit 119. The display unit 120 is a monitor that displays the operation screen of the control device 116 and notifications, alarms, etc. output from the control device 116.

[0018] (Operation of the Automated Analyzer) In the automated analyzer 101 configured as described above, the sample dispensing mechanism 104 and the reagent dispensing mechanism 108 dispense the sample and reagent from the sample cup 102 and the reagent bottle 106, respectively, into the same reaction cell 109. The mixture of the sample and the reagent is agitated by the ultrasonic agitation mechanism 114. In this embodiment, the mixture of the sample and the reagent is referred to as the agitated liquid because it is the object to be agitated by the ultrasonic agitation mechanism 114. In this embodiment, the reaction disk 110 rotates counterclockwise in a plan view. As the reaction disk 110 rotates, the reaction cells 109 containing the agitated liquid are sequentially transported to the front of the ultrasonic agitation mechanism 114, where the agitated liquid is agitated and mixed without contact by the ultrasonic agitation mechanism 114. If the reaction cell 109 is interfered with by the mixing of the agitated liquid, it is transported between the light source 111 and the absorbance meter 112 by the rotation of the reaction disk 110, and the absorbance of the agitated liquid, i.e., the reaction liquid, is measured. After the measurement of the absorbance of the liquid to be mixed is completed, the reaction cell 109 is transported to the position of the cleaning mechanism 118 by the rotation of the reaction disk 110, and is cleaned by the cleaning mechanism 118. Another sample is dispensed from the sample cup 102 by the sample dispensing mechanism 104 into the reaction cell 109 that has been interrupted by the cleaning, and the above sequence is repeated. These sequence operations are performed in parallel for multiple samples.

[0019] (Ultrasonic Agitation Mechanism) Fig. 2 is a schematic diagram showing the cross section of the ultrasonic agitation mechanism 114 and its drive system. The cross section of the ultrasonic agitation mechanism 114 shown in Fig. 2 is a cross section of the ultrasonic agitation mechanism 114 cut along a vertical plane passing through the center of rotation of the reaction disk 110.

[0020] The ultrasonic stirring mechanism 114 includes an ultrasonic vibrator 203, a fixing base 204, and a reflecting plate 205. The ultrasonic vibrator 203 includes a piezoelectric body 201 and a plurality of electrodes 202 attached to the piezoelectric body 201. The electrodes 202 are arranged vertically and are attached to the piezoelectric body 201 so as to sandwich the piezoelectric body 201 between them. The fixing base 204 supports the ultrasonic vibrator 203, and the ultrasonic vibrator 203 is installed in the housing of the automatic analyzer 101. The reflecting plate 205 is arranged opposite the ultrasonic vibrator 203.

[0021] The automatic analyzer 101 is equipped with a donut-shaped reaction tank 206 in which a heat-retaining solvent 207 is stored. The ultrasonic stirring mechanism 114 is installed inside the reaction tank 206. The reaction cell 109 in which a liquid to be stirred 208 is stored is inserted into the reaction tank 206 and immersed in the heat-retaining solvent 207. The reaction cell 109 moves with the rotation of the reaction disk 110 and is transported between the ultrasonic vibrator 203 and the reflector 205 to stir the liquid to be stirred 208.

[0022] The ultrasonic vibrator 203 is connected to the control device 116 or the drive circuit 115 via a selection unit 117. The selection unit 117 includes a circuit connection selector switch 209 and a segment selector switch 210. The circuit connection selector switch 209 switches the connection of the ultrasonic vibrator 203 between the drive circuit 115 and the control device 116. The ultrasonic vibrator 203 is divided into multiple segments 211 arranged vertically. Each segment 211 has at least one electrode 202 of the same shape (one on each side in this embodiment) on one or both sides of the piezoelectric body 201, and each emits ultrasonic waves 113. The segment selector switch 210 selects the electrode 202 to which voltage is applied and selects the segment 211 to emit the ultrasonic waves 113. Because the ultrasonic vibrator 203 has such a segment structure, it is possible to select a segment to emit ultrasonic waves 113 that are effective for stirring the liquid to be stirred 208, even if the liquid level of the liquid to be stirred 208 inside the reaction cell 109 varies depending on the analysis item. The circuit connection changeover switch 209 and the segment changeover switch 210 may be, for example, a relay or a multiplexer.

[0023] The control device 116 includes a measurement unit 213 that measures the electrical impedance spectrum, a normal range definition unit 214 that will be described in detail using Fig. 4, a storage unit 215 that will be described in detail using Fig. 7, and a diagnosis unit 216 that performs fault diagnosis of the ultrasound transducer 203. The measurement unit 213, normal range definition unit 214, storage unit 215, and diagnosis unit 216 are functions provided in the control device 116, and may be realized by hardware elements such as circuits, or by software elements such as programs.

[0024] (Ultrasonic Stirring Operation) When the ultrasonic vibrator 203 is connected to the drive circuit 115 via the circuit connection changeover switch 209 and the segment changeover switch 210 and a voltage is applied to the ultrasonic vibrator 203 by the drive circuit 115, ultrasonic waves 113 are generated in the segment 211 connected to the drive circuit 115. The generated ultrasonic waves 113 pass through the heat-retaining solvent 207 and the liquid to be stirred 208 inside the reaction cell 109, propagate to the reflector 205, are reflected by the reflector 205, and pass again through the liquid to be stirred 208 inside the reaction cell 109. At this time, acoustic streaming is generated in the propagation direction of the ultrasonic waves 113, so that a swirling flow 212 is generated in the liquid to be stirred 208 by the ultrasonic waves 113 that pass from the ultrasonic vibrator 203 through the liquid to be stirred 208 and head toward the reflector 205, and the ultrasonic waves 113 that are reflected by the reflector 205, change angle, and pass through the liquid to be stirred 208. In this way, a swirling flow 212 is generated in the liquid to be stirred 208, thereby mixing the specimen and the reagent.

[0025] By using the segment changeover switch 210 to select the segment 211 to be connected to the drive circuit 115 , it is possible to emit the ultrasonic wave 113 from any of the segments 211 .

[0026] (Impedance Measurement Operation) Fault diagnosis of the ultrasonic transducer 203 is performed by measuring the electrical impedance spectrum of the ultrasonic transducer 203. As will be described later in detail, in the control device 116, a normal range of electrical impedance specific to the ultrasonic transducer 203 is defined as described later based on the measured value of the electrical impedance obtained by applying a voltage to the electrodes 202, and the defined normal range is stored in the memory unit 215. Then, at the time of a subsequent diagnosis (for example, before analysis of a sample), the control device 116 compares the measured value of the electrical impedance obtained by applying a voltage to the electrodes 202 with the normal range to perform fault diagnosis of the ultrasonic transducer 203. The ultrasonic transducer 203 used to define the normal range is the same individual as the ultrasonic transducer 203 being diagnosed for fault.

[0027] The electrical impedance spectrum used for fault diagnosis is measured by connecting the ultrasonic transducer 203 to the control device 116 via the circuit connection changeover switch 209 and the segment changeover switch 210, and applying a voltage to the ultrasonic transducer 203 by the measurement unit 213 of the control device 116 that is lower than the voltage applied by the drive circuit 115. The electrical impedance spectrum is obtained by sweeping a voltage of an arbitrary frequency and obtaining the electrical response. When measuring the electrical impedance spectrum, it is also possible to measure the frequency characteristics of the phase difference between the voltage and current. The voltage of an arbitrary frequency can be generated, for example, by a direct digital synthesizer.

[0028] As in the ultrasonic agitation operation, in the impedance measurement operation, the electrical impedance spectrum of each segment 211 can be measured by switching the segment 211 connected to the control device 116 using the segment changeover switch 210.

[0029] (Changes in Electrical Impedance) FIG. 3 is a diagram illustrating the difference in the electrical impedance spectra between a normal ultrasonic transducer 203 and a faulty ultrasonic transducer 203. The electrical impedance spectrum represented by a solid line in FIG. 3 is the electrical impedance spectrum 301 of the normal ultrasonic transducer 203. The electrical impedance spectrum represented by a dashed line is the electrical impedance spectrum 302 of the faulty ultrasonic transducer 203. The electrical impedance spectrum of the ultrasonic transducer 203 has a minimum value (minimum electrical impedance) at the resonant frequency. When a voltage of the resonant frequency 303 is applied, the vibration displacement of the ultrasonic transducer 203 is large, so the ultrasonic transducer 203 is generally used at a frequency near the resonant frequency. As shown in FIG. 3, the resonant frequency 305 of the faulty ultrasonic transducer 203 changes from the resonant frequency 303 in the normal state. Furthermore, compared to the minimum electrical impedance 304 at the resonant frequency 303 of the normal ultrasonic transducer 203, the electrical impedance 306 at the resonant frequency 305 of the faulty ultrasonic transducer 203 is larger. Therefore, it is possible to set a normal range for the resonance frequency and the electrical impedance at that resonance frequency and perform a fault diagnosis on the ultrasonic transducer 203 .

[0030] In this case, in addition to a malfunction of the ultrasonic transducer 203, the measurement environment, such as the length and shape (wiring path) of the electrical wiring from the measuring unit 213 to the ultrasonic transducer 203, can affect the measured electrical impedance. In particular, the measured electrical impedance value decreases when the electrical wiring is long. Therefore, a diagnostic method that compares the measured electrical impedance value with a general normal range cannot determine whether the cause of the measured electrical impedance value being lower than the normal range is a malfunction of the ultrasonic transducer 203 or the long electrical wiring of the ultrasonic transducer 203. Therefore, it is effective to define a normal range that excludes factors that affect the measured electrical impedance value other than a malfunction of the ultrasonic transducer 203, and to diagnose a malfunction of the ultrasonic transducer 203 based on a comparison of the measured electrical impedance value at the time of diagnosis with the normal range.

[0031] In this embodiment, fault diagnosis that eliminates factors affecting the electrical impedance measurement value other than a fault in the ultrasonic transducer 203 is achieved by defining a normal range by the normal range definition unit 214. The influencing factors are eliminated by performing the definition of the normal range and the fault diagnosis on the same system. The term "system" here refers to a system related to the measurement of electrical impedance, including the measurement unit 213, the ultrasonic transducer 203, and the electrical wiring connecting the measurement unit 213 and the ultrasonic transducer 203. The term "same system" means that the ultrasonic transducer 203 and its electrical wiring are the same when the normal range is defined and when the diagnosis is performed. If the measurement unit 213 is implemented by hardware, it is desirable that the measurement unit 213 is also the same. If the measurement unit 213 is implemented by software, it is desirable that the identity of the program, etc., is ensured. In this embodiment, factors that are eliminated as influencing the electrical impedance measurement value of the ultrasonic transducer 203 include, for example, individual differences between the ultrasonic transducer used to measure the electrical impedance value when the normal range is defined and the ultrasonic transducer being diagnosed for fault, the length of the electrical wiring, the shape (wiring path) of the electrical wiring, etc.

[0032] (Example of definition of normal range) FIG. 4 is an explanatory diagram of the normal range used in fault diagnosis of the ultrasonic transducer 203. The normal range is defined by the normal range definition unit 214 of the control device 116. First, the measurement unit 213 applies a voltage to a predetermined electrode 202 of a normal ultrasonic transducer 203, and measures the electrical impedance spectrum 301 for that electrode 202. The ultrasonic transducer 203 used when defining the normal range is assumed to be in a normal state. Based on the measurement value of the electrical impedance spectrum 301 obtained from this normal ultrasonic transducer 203, a normal range of the electrical impedance specific to that predetermined electrode 202 of the ultrasonic transducer 203 is defined. The normal range is defined based on feature quantities extracted from the electrical impedance spectrum 301.

[0033] The feature quantities that define the normal range are the resonant frequency 303 of the ultrasonic transducer 203 and the minimum electrical impedance 304 at this resonant frequency 303. Furthermore, the impedance on the electrical impedance spectrum 301 is maximum at a frequency higher than the resonant frequency 303. The frequency at which the impedance on the electrical impedance spectrum 301 is maximum is called the anti-resonant frequency 401. In this embodiment, the second feature quantities that are used are the anti-resonant frequency 401 of a normal ultrasonic transducer 203 and the maximum electrical impedance 402 at the anti-resonant frequency 401.

[0034] Furthermore, the control device 116 defines the normal ranges using the normal range definition unit 214 based on the variations in feature quantities (such as the resonant frequency 303) extracted as described below for each electrical impedance spectrum obtained by multiple measurements using the electrode 202. For example, the normal ranges may be determined by repeatedly measuring the electrical impedance a predetermined number N (e.g., 20 times), calculating the standard deviation σ of the N feature quantities obtained by the repeated measurements, and defining the normal range as the average value ±3σ of the feature quantities. The ±3σ values ​​may be calculated for each of the resonant frequency 303, the minimum electrical impedance 304, the antiresonant frequency 401, and the maximum electrical impedance 402.

[0035] 4 , the normal range includes a first normal range 403 defined by feature quantities of a range of ±3σ of the average value of minimum electrical impedance 304 and a range of ±3σ of the average value of resonance frequency 303 corresponding to minimum electrical impedance 304. Furthermore, in this embodiment, the normal range includes a second normal range 404 defined by feature quantities of a range of ±3σ of the average value of maximum electrical impedance 402 and a range of ±3σ of the average value of anti-resonance frequency 401 corresponding to maximum electrical impedance 402. In addition to these, values ​​that characterize the waveform of the electrical impedance spectrum, such as the difference between resonance frequency 303 and anti-resonance frequency 401 and the difference between minimum electrical impedance 304 and maximum electrical impedance 402, can also be used as feature quantities that define the normal range.

[0036] The normal ranges (first normal range 403 and second normal range 404 ) defined by the normal range definition unit 214 in the above manner are stored in the storage unit 215 .

[0037] (Another example of definition of normal range) When the normal range is defined based on the variation in electrical impedance measurements taken multiple times using the same electrode 202 as described above, if the measurement reproducibility is high and the standard deviation σ is small, the normal range may become excessively narrow and the margin for fault diagnosis may not be properly ensured.

[0038] As described above, the ultrasonic transducer 203 includes a plurality of electrodes 202 of the same shape. This ultrasonic transducer 203 utilizes a segmented structure, and the control device 116 can define a normal range from the variation in the feature amount (resonant frequency 303, etc.) extracted from the electrical impedance spectrum for each electrode 202, that is, for each segment 211. In this case, the normal range can be defined in a shorter time than when repeated measurements are performed for each segment 211.

[0039] (Fault Diagnosis) Figure 5 is an explanatory diagram of fault diagnosis of the ultrasonic transducer 203 using the normal range defined by the normal range definition unit 214. After defining the normal range, as shown in Figure 5, when diagnosing the ultrasonic transducer 203, the control device 116 measures a new electrical impedance spectrum 405 for the ultrasonic transducer 203 and compares a resonant frequency 406 related to the electrical impedance spectrum 405 and an electrical impedance 407 at the resonant frequency 406 with a first normal range 403. At the same time, the control device 116 compares an anti-resonant frequency 408 related to the electrical impedance spectrum 405 and an electrical impedance 409 at the anti-resonant frequency 408 with a second normal range 404. If the resonant frequency 406 and the electrical impedance 407 fall within the first normal range 403 and the anti-resonant frequency 408 and the electrical impedance 409 fall within the second normal range 404, the control device 116 diagnoses the ultrasonic transducer 203 as being in a normal state. Conversely, the control device 116 diagnoses the ultrasonic transducer 203 as being in a fault state when the resonant frequency 406 and the electrical impedance 407 are not within the first normal range 403, or when the anti-resonant frequency 408 and the electrical impedance 409 are not within the second normal range 404. In the example of Fig. 5, the coordinates defined by the resonant frequency 406 and the electrical impedance 407 are outside the first normal range 403, and the ultrasonic transducer 203 associated with the electrical impedance spectrum 405 is determined to be in a fault state.

[0040] 6 is a diagram for explaining the definition of the normal range of the electrical impedance of the ultrasonic transducer 203 and the timing for performing a diagnosis of the ultrasonic transducer 203. The phases related to the diagnosis of the operation of the same ultrasonic transducer 203 are roughly divided into two: a first phase 501 in which the normal range to be used for the fault diagnosis is defined from the electrical impedance spectrum of the ultrasonic transducer 203, and a second phase 502 in which the fault diagnosis of the ultrasonic transducer 203 is performed.

[0041] The first phase 501 is the timing at which the electrical impedance of the ultrasonic transducer 203 attached to the automatic analyzer 101 can be measured and the normal state of the ultrasonic transducer 203 is guaranteed. In other words, the first phase 501 is the timing shortly after a new ultrasonic transducer 203 is installed in the automatic analyzer 101, for example, the timing before the ultrasonic transducer 203 begins to be used for analyzing samples. Examples of the first phase 501 include before the automatic analyzer 101 is shipped, before operation begins after delivery, and when the ultrasonic transducer 203 is replaced with a new one after operation begins. The normal range of the electrical impedance specific to the ultrasonic transducer 203 is defined based on the measured value of the electrical impedance obtained at the timing at which the normal state of the ultrasonic transducer 203 is estimated.

[0042] The second phase 502 is the timing for diagnosing the state of the ultrasonic transducer 203 in order to analyze the sample in the automatic analyzer 101. For example, an opportunity to diagnose a fault in the ultrasonic transducer 203 prior to the analysis of the sample is an example of the second phase 502.

[0043] Whether the ultrasound transducer 203 is in a normal state or a fault state is determined based on whether the feature extracted from the electrical impedance spectrum measured in the second phase 502 is within or outside the normal range defined in the first phase 501. At this time, the electrical impedances in the first phase 501 and the second phase 502 that are compared with each other are characterized in that they are measured using the same system. This means that the ultrasound transducer 203 is the same individual at the time of defining the normal range and at the time of diagnosis, and the electrical wiring connecting the control device 116 to the ultrasound transducer 203 is the same, and the measurement environment, such as the wiring length and wiring shape, is physically the same. Therefore, fluctuations in the measured value of the electrical impedance due to factors other than a fault in the ultrasound transducer 203, which are caused by individual differences in the ultrasound transducer 203 or differences in the measurement system, such as the length and shape of the electrical wiring, are suppressed.

[0044] 6 , when the ultrasonic transducer 203 of the first system 503 breaks down and is replaced with a new one, the system including the new ultrasonic transducer 203 is distinguished as a second system 504 different from the first system 503. In this embodiment, each time a system changes in this manner, a normal range specific to each system is defined for each system in the first phase 501. The target of fault diagnosis based on the normal range defined for the first system 503 is only the ultrasonic transducer 203 included in the first system 503. Similarly, the target of fault diagnosis based on the normal range defined for the second system 504 is only the ultrasonic transducer 203 included in the second system 504, and the target of fault diagnosis based on the normal range defined for the third system 505 is only the ultrasonic transducer 203 included in the third system 505.

[0045] When multiple ultrasonic transducers 203 are installed in the automatic analyzer 101, these multiple ultrasonic transducers 203 are treated as different systems, and normal ranges are defined individually for each of the multiple ultrasonic transducers 203.

[0046] 7 is a flowchart showing an example of a series of processing steps of the control device 116 related to the definition of the normal ranges performed in the first phase. As described above, the first normal range 403 and the second normal range 404 are defined in the first phase 501, in which the normal state of the ultrasonic transducer 203 is guaranteed. For example, the normal ranges are defined when the ultrasonic transducer 203 is attached to the automatic analyzer 101 in the production factory of the automatic analyzer 101, when the automatic analyzer 101 is installed at a customer's site, when the ultrasonic transducer 203 is replaced, etc.

[0047] 7 starts, in step S101, the control device 116 controls the circuit connection changeover switch 209 of the selection unit 117 so that the ultrasonic transducer 203 is connected to the control device 116, and measures the electrical impedance spectrum 301 using the measurement unit 213. At this time, the segment changeover switch 210 is controlled to sequentially switch the segments 211 connected to the control device 116, and the electrical impedance spectrum 301 is measured multiple times for each segment 211.

[0048] Step S102 In the following step S102, the control device 116 extracts a feature amount in a normal state for each segment 211 from the electrical impedance spectrum 301 measured in step S101.

[0049] In step S103, the control device 116, using the diagnosis unit 216, compares the feature quantity extracted in step S102 with an initial determination range pre-stored in the memory unit 215. The initial determination range, like the normal range, is a range of frequency and impedance values ​​defined on the graph in Figure 4, and is a preset value that has been empirically or theoretically set in advance to detect an obviously abnormal state. This initial determination is used to check for initial defects (e.g., loose connectors) in the assembly of the automatic analyzer 101 and the measurement circuit and control including the measurement unit 213.

[0050] Step S104: In step S104, the control device 116 determines whether the feature extracted in step S102 is within the initial determination range. If the feature is within the initial determination range, the control device 116 proceeds to step S105, where the normal range is defined. If the feature is outside the initial determination range, the control device 116 proceeds to step S107.

[0051] Step S105 When the procedure moves from step S104 to step S105, the control device 116 causes the normal range definition unit 214 to define the first normal range 403 and the second normal range 404 to be used in the fault diagnosis of the ultrasonic transducer 203 for each ultrasonic transducer 203 (for each segment 211 in this embodiment). These defined normal ranges are specific to the system, and will be used in each subsequent fault diagnosis (second phase 502) in the same system unless the system is updated due to replacement of the ultrasonic transducer 203, etc.

[0052] In the following step S106, the control device 116 stores the normal range defined in step S105 in the storage unit 215, and ends the flow of Fig. 7. When diagnosing the ultrasound transducer 203 thereafter, the normal range corresponding to the ultrasound transducer 203 to be diagnosed is called from the storage unit 215.

[0053] Step S107: When the procedure moves from step S104 to step S107, the control device 116 outputs an alarm to the display unit 120 to notify that an initial defect, such as improper installation of the ultrasonic vibrator 203, has been detected, and the flow of FIG. 7 ends.

[0054] (Processing Flow of the Second Phase) FIG. 8 is a flowchart showing an example of a series of processing steps performed by the control device 116 in the second phase for fault diagnosis of the ultrasonic transducer 203. The second phase 502 is a stage in which the state of the ultrasonic transducer 203 is diagnosed when the automated analyzer 101 is started up or during analysis preparation operations performed before the start of sample analysis. If the automated analyzer 101 is diagnosed as having a fault in the second phase 502, the automated analyzer 101 does not perform the sample analysis operation, thereby avoiding the consumption of the sample and reagent. Alternatively, if the automated analyzer 101 has multiple ultrasonic stirring mechanisms 114, when one ultrasonic transducer 203 is diagnosed as having a fault, the automated analyzer 101 switches to a sequence that does not use the ultrasonic stirring mechanism 114 containing the faulty ultrasonic transducer 203 as a temporary measure, and starts the analysis operation using the remaining ultrasonic transducers 203. As with the definition of the normal range performed in the first phase 501, the control device 116 also performs fault diagnosis for each ultrasonic transducer 203 and each segment 211.

[0055] Step S201 When the flow of FIG. 8 starts, the control device 116 measures the current electrical impedance spectrum 405 of the ultrasound transducer 203 of the diagnostic target in step S201.

[0056] Step S202 In the following step S202, the control device 116 extracts a feature amount from the current electrical impedance spectrum 405 of the ultrasound transducer 203 to be diagnosed.

[0057] Step S203 In step S203, the control device 116 calls up the normal range specific to the ultrasound transducer 203 to be diagnosed from the storage unit 215, and compares the feature amount extracted in step S202 with the normal range.

[0058] Step S204: In step S204, the control device 116 determines whether the feature extracted in step S202 is within a normal range. If the feature is within the normal range, the control device 116 proceeds to step S205. If the feature is outside the normal range, the control device 116 proceeds to step S206.

[0059] Step S205: When the procedure moves from step S204 to step S205, the control device 116 determines that the ultrasonic transducer 203 is normal, stores the feature determined to be normal in the memory unit 215, terminates the flow of Figure 8, continues the operation of the automatic analyzer 101, and moves the procedure to sample analysis, etc.

[0060] Step S206 When the procedure moves from step S204 to step S206, the control device 116 determines that the ultrasonic transducer 203 is in a faulty state, and stores the feature amount indicating that the ultrasonic transducer 203 is in a faulty state in the storage unit 215.

[0061] Step S207 In the following step S207, the control device 116 outputs a failure alarm to the output device (for example, the display unit 120) to notify the user that the ultrasonic transducer 203 has been determined to be in a faulty state.

[0062] Step S208: Further, in step S208, the control device 116 displays the detailed results of the fault diagnosis on the display unit 120, completes the flow of FIG. 8, and stops the operation of the automatic analyzer 101, or switches to a sequence that does not use the faulty ultrasonic transducer 203, and continues the operation of the automatic analyzer 101.

[0063] (Display of Fault Diagnosis Results) Figure 9 shows an example of the diagnostic results of the ultrasonic transducer 203 output by the control device 116 to the display unit 120. Figure 9 shows an example of a report 801 of the fault diagnosis of the ultrasonic transducer 203 displayed for each segment 211. The report 801 displays "OK," meaning a normal state, or "NG," meaning a fault state, for each segment 211 of segment Nos. 1 to 13. Figure 9 also shows an example in which multiple ultrasonic transducers 203 are installed in the automated analyzer 101. The columns labeled "Element 1," "Element 2," ..., and "Element 6" each represent the diagnostic results of a different ultrasonic transducer 203. The diagnostic results of each segment 211 are displayed for each ultrasonic transducer 203. In the example of Figure 9, segments Nos. 3 to 7 and 10 to 12 of "Element 3" are determined to be in a fault state. Also, as shown in FIG. 9, the serial number (Ser) of the ultrasonic transducer 203 and the date (Date) on which the ultrasonic transducer 203 was attached to the automatic analyzer 101 can be displayed for each ultrasonic transducer 203, so that the elapsed time since the current normal range for each ultrasonic transducer 203 was defined can be known.

[0064] (Effects) (1) According to this embodiment, when diagnosing a fault in the ultrasonic transducer 203, the measured value of the electrical impedance of the ultrasonic transducer 203 is evaluated by comparing it with a specific normal range previously acquired from the ultrasonic transducer 203 itself to be diagnosed. Therefore, fluctuations in the measured value of the electrical impedance due to factors other than a fault in the ultrasonic transducer 203 are suppressed, and fluctuations in the electrical impedance from the defined normal range can be considered to be mainly due to changes in the state of the ultrasonic transducer 203. Therefore, it is possible to suppress erroneous diagnoses in which a normal ultrasonic transducer 203 is determined to be abnormal, thereby improving the reliability of fault diagnoses of the ultrasonic transducer 203. Furthermore, it is possible to suppress the occurrence of unnecessary replacement work for the ultrasonic transducer 203, thereby suppressing a decrease in the availability rate of the automatic analyzer 101 and suppressing the labor hours and parts costs required for unnecessary replacement of the ultrasonic transducer 203.

[0065] Furthermore, since the normal range of the ultrasound transducer 203 is defined using that ultrasound transducer 203, there is also the advantage that a series of advance preparations, such as preparing a large number of normal ultrasound transducers and measuring the individual electrical impedances, is not necessary to generate a normal population for defining the normal range.

[0066] (2) The normal range specific to each ultrasonic transducer 203 includes a first normal range 403 defined by the minimum electrical impedance 304 of the ultrasonic transducer 203 and the corresponding resonant frequency 303 as feature quantities. In this embodiment, the normal range specific to each ultrasonic transducer 203 also includes a second normal range 404 defined by the maximum electrical impedance 402 of the ultrasonic transducer 203 and the corresponding antiresonant frequency 401 as feature quantities. Fault diagnosis that is not affected by individual differences in the ultrasonic transducer 203 or the length of electrical wiring is possible by evaluating the electrical impedance during diagnosis using the first normal range 403. Additionally, by evaluating the second normal range 404, it is possible to confirm a waveform specific to impedance that exhibits the maximum electrical impedance 402 at an antiresonant frequency 401 higher than the resonant frequency 303. It cannot be said that there is absolutely no possibility that the feature quantity accidentally falls within the first normal range 403 due to another abnormality in the measurement system, such as a short circuit, despite the ultrasonic transducer 203 being abnormal. In contrast, by evaluating the electrical impedance using the second normal range 404 at the anti-resonance frequency 401 in addition to the evaluation using the first normal range 403, it is possible to detect failures in the ultrasonic vibrator 203 more accurately, and the reliability of failure diagnosis of the ultrasonic vibrator 203 can be further improved.

[0067] (3) As described above, the control device 116 measures the electrical impedance spectrum multiple times for each ultrasonic transducer 203 and each segment 211, extracts feature values ​​for each measured electrical impedance spectrum, and defines the first normal range 403 and the second normal range 404 based on the variation in these feature values. This makes it possible to set appropriate and unique values ​​for each ultrasonic transducer 203 for the size of the normal range, specifically, the range of frequency and impedance value.

[0068] (4) Furthermore, in the case of an ultrasonic transducer 203 having a plurality of electrodes 202 of the same shape, the control device 116 can also define the first normal range 403 and the second normal range 404 based on the variation in the feature amount extracted from the electrical impedance spectrum for each electrode 202 of the ultrasonic transducer 203. In this case, it is not necessary to measure the electrical impedance multiple times, and the first normal range 403 and the second normal range 404 can be defined by one or a small number of measurements.

[0069] (Modifications) The present invention is not limited to the above-described embodiments and may include various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and are not necessarily limited to those including all of the described configurations. For example, it is possible to replace some of the configurations with other configurations. It is also possible to delete some of the configurations of the embodiments or add other configurations.

[0070] For example, in the above embodiment, it is also possible to define the normal range in stages and determine deterioration of the ultrasonic transducer 203. FIG. 10 is an explanatory diagram of the normal range used for fault diagnosis of the ultrasonic transducer 203 in this modified example. As shown in FIG. 10 , in this example, the first normal range 403 is divided into a first area A and a second area B that includes the first area A. Specifically, the lower limit of the frequency in the first area A is equal to or greater than the lower limit of the frequency in the second area B, and the upper limit of the frequency in the first area A is equal to or less than the upper limit of the frequency in the second area B. Furthermore, the lower limit of the impedance in the first area A is equal to or greater than the lower limit of the impedance in the second area B, and the upper limit of the impedance in the first area A is equal to or less than the upper limit of the impedance in the second area B. On the graph in FIG. 10 , the area of ​​the first area A is smaller than the area of ​​the second area B. As an example, the second area B can be defined as the average value of the feature quantity obtained by repeated measurements ±3σ, similar to the first normal range 403 in Figure 4, and the first area A can be defined as the average value of the feature quantity ±2σ.

[0071] In this case, if the measured electrical impedance values ​​obtained by applying a voltage to each electrode 202 of the ultrasonic transducer 203 during the fault diagnosis in the second phase 502 are within the range of the first area A defined for each, the control device 116 diagnoses the segments 211 as being in a normal state. Furthermore, if the measured electrical impedance values ​​obtained by applying a voltage to each electrode 202 during the diagnosis are outside the range of the second area B defined for each, the control device 116 diagnoses the segments 211 as being in a faulty state. Furthermore, if the measured electrical impedance values ​​obtained by applying a voltage to each electrode 202 during the diagnosis are outside the range of the first area A and within the range of the second area B, the control device 116 diagnoses the segments 211 as being in a degraded state. A degraded state is, for example, a state in which the segment has not yet reached a faulty state but has begun to deteriorate and may transition to a faulty state within a predetermined period of time.

[0072] Such stepwise definition of the normal range is not limited to the first normal range 403, but can also be applied to the second normal range 404 in the same manner.

[0073] Furthermore, although an example has been described above in which the control device 116 defines the normal range and performs fault diagnosis, the essence of the invention is to perform fault diagnosis of the normal range system and the ultrasonic transducer 203 in the same system. To achieve this, it is also possible to set a predetermined normal range from the measured value of the electrical impedance in the first phase 501 without using the control device 116, and then perform fault diagnosis of the ultrasonic transducer 203 by comparing the electrical impedance measured in the second phase 502 with the normal range.

[0074] 100...diagnostic system, 101...automatic analyzer, 116...controller, 120...display unit (output device), 201...piezoelectric body, 202...electrode, 203...ultrasonic transducer, 301...electrical impedance spectrum, 303...resonant frequency (frequency corresponding to minimum electrical impedance), 304...minimum electrical impedance, 401...anti-resonant frequency (frequency corresponding to maximum electrical impedance), 402...maximum electrical impedance, 403...first normal range (normal range), 404...second normal range (normal range), 501...first phase (timing at which the normal state of the ultrasonic transducer is estimated), A...first area, B...second area

Claims

1. An automatic analyzer comprising a piezoelectric body, an ultrasonic vibrator including an electrode attached to the piezoelectric body, and a control device for diagnosing a failure of the ultrasonic vibrator, wherein the control device defines and stores a normal range of the electrical impedance specific to the ultrasonic vibrator based on a measured value of the electrical impedance obtained by applying a voltage to the electrode, and compares the measured value of the electrical impedance obtained by applying a voltage to the electrode during diagnosis with the normal range to diagnose a failure of the ultrasonic vibrator.

2. The automatic analyzer according to claim 1, wherein the ultrasonic vibrator used to define the normal range and the ultrasonic vibrator to be diagnosed for failure are the same individual.

3. The automatic analyzer according to claim 1, wherein the normal range is defined based on a feature amount extracted from a spectrum of the electrical impedance.

4. The automatic analyzer according to claim 3, wherein the normal range includes a first normal range defined using the minimum value of the electrical impedance and the frequency corresponding to the minimum value as the feature amounts.

5. The automatic analyzer according to claim 4, wherein the normal range includes a second normal range defined using the maximum value of the electrical impedance and the frequency corresponding to the maximum value as the feature amounts.

6. The automatic analyzer according to claim 3, wherein the control device defines the normal range from the variation in the feature amounts extracted for each electrical impedance spectrum obtained by a plurality of measurements using the electrode.

7. The automatic analyzer according to claim 3, wherein the ultrasonic vibrator includes a plurality of electrodes having the same shape, and the control device defines the normal range from the variation in the feature amounts extracted from the electrical impedance spectra for each electrode.

8. The automatic analyzer according to claim 1, wherein the normal range of the electrical impedance specific to the ultrasonic vibrator is defined based on a measured value of the electrical impedance obtained at a timing when the normal state of the ultrasonic vibrator is estimated.

9. In the automatic analysis apparatus according to claim 1, the normal range is divided into a first area and a second area including the first area, and the control device diagnoses that the ultrasonic vibrator is in a normal state when the measured value of the electrical impedance obtained by applying a voltage to the electrode at the time of diagnosis is within the range of the first area, diagnoses that the ultrasonic vibrator is in a failure state when the measured value of the electrical impedance obtained by applying a voltage to the electrode at the time of diagnosis is outside the range of the second area, and diagnoses that the ultrasonic vibrator is in a deteriorated state when the measured value of the electrical impedance obtained by applying a voltage to the electrode at the time of diagnosis is outside the range of the first area and within the range of the second area. An automatic analysis apparatus characterized by that.

10. In the automatic analysis apparatus according to claim 1, when the control device diagnoses that the ultrasonic vibrator is malfunctioning, the automatic analysis apparatus is characterized in that it outputs an alarm to an output device.

11. A diagnostic system including a piezoelectric body and an electrode attached to the piezoelectric body, and having a control device for diagnosing a failure of an ultrasonic vibrator provided in an automatic analysis apparatus, wherein the control device defines and stores a normal range of the electrical impedance specific to the ultrasonic vibrator based on the measured value of the electrical impedance obtained by applying a voltage to the electrode, and compares the measured value of the electrical impedance obtained by applying a voltage to the electrode at the time of diagnosis with the normal range to diagnose a failure of the ultrasonic vibrator. A diagnostic system characterized by that.

12. In the diagnostic system according to claim 11, the control device is provided in the automatic analysis apparatus. A diagnostic system characterized by that.

13. A diagnostic method for diagnosing a failure of an ultrasonic vibrator provided in an automatic analysis apparatus, including a piezoelectric body and an electrode attached to the piezoelectric body, wherein a normal range of the electrical impedance specific to the ultrasonic vibrator is defined based on the measured value of the electrical impedance obtained by applying a voltage to the electrode, and the measured value of the electrical impedance obtained by applying a voltage to the electrode at the time of diagnosis is compared with the normal range to diagnose a failure of the ultrasonic vibrator. A diagnostic method characterized by that.

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