Automatic analyzer and position measurement method therefor

Abstract

To provide an automatic analyzer capable of measuring a position of an object relative to a stirring mechanism with high accuracy.SOLUTION: In an automatic analyzer having a stirring mechanism that stirs a specimen and a reagent by ultrasonic waves, the stirring mechanism includes: a plurality of ultrasonic elements that oscillates the ultrasonic waves; an amplifier that applies a voltage to the ultrasonic elements; a detection unit that detects electrical signals generated from the ultrasonic elements upon reception of reflected waves produced when the ultrasonic waves are reflected by a measurement target; and a calculation unit that measures a relative position between the stirring mechanism and the measurement target on the basis of the electrical signals relating to the reflected waves detected via the plurality of ultrasonic elements with respect to the ultrasonic waves oscillated from the plurality of ultrasonic elements.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an automatic analyzer and a position measurement method thereof. [Background technology]

[0002] Automated analyzers equipped with a stirring mechanism that uses ultrasonic waves to stir samples and reagents in a reaction vessel are known. Ultrasound has the advantage of being able to stir samples and reagents without contact, thereby preventing carryover of the sample or reagent. Also known is a technique that uses ultrasonic waves emitted by the stirring mechanism to estimate the presence or absence of a mixed liquid containing a sample and a reagent, as well as the liquid level. For example, Patent Document 1 discloses a technique in which multiple electrodes are provided in the height direction on a piezoelectric element, which is an ultrasonic oscillation source, and the liquid level is estimated based on the electrical impedance measured when a voltage is applied to the electrodes. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-97912 Summary of the Invention [Problem to be solved by the invention]

[0004] In the technology described in Patent Document 1, an electrode to be measured is selected, a voltage is applied to the selected electrode to generate an ultrasonic wave, and the electrical impedance of the selected electrode is measured. As a result, the target (mixed liquid) can only be detected at the position of the electrode, and the detection accuracy depends on the pitch of the electrodes.

[0005] An object of the present invention is to provide an automatic analyzer that can measure the position of an object relative to a stirring mechanism with high accuracy. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, the present invention provides an automatic analyzer having a stirring mechanism that stirs a sample and a reagent using ultrasound, wherein the stirring mechanism comprises a plurality of ultrasonic elements that emit the ultrasound, an amplifier that applies a voltage to the ultrasonic elements, a detection unit that detects an electrical signal generated from the ultrasonic elements that receive a reflected wave generated when the ultrasound is reflected by the object to be measured, and a calculation unit that measures the relative position between the stirring mechanism and the object to be measured based on the electrical signal related to the reflected wave detected via the plurality of ultrasonic elements in response to the ultrasound emitted from the plurality of ultrasonic elements. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide an automatic analyzer that can measure the position of an object relative to a stirring mechanism with high accuracy.

[0008] Problems, configurations, and effects other than those described above will become apparent from the following description of the embodiments. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a top view showing a schematic configuration of an automatic analyzer. [Figure 2] FIG. 2 is a diagram showing a schematic configuration of a stirring mechanism in a stirring mode (normal mode). [Figure 3] FIG. 10 is a schematic diagram showing the state of the stirring mechanism when ultrasonic waves are emitted for position measurement. [Figure 4] FIG. 10 is a schematic diagram showing the state of the stirring mechanism when detecting a reflected wave of an ultrasonic wave emitted for position measurement. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that substantially the same or similar components are denoted by the same reference numerals, and redundant descriptions may be omitted.

[0011] <Overall configuration of the automatic analyzer> Fig. 1 is a top view showing the schematic configuration of an automatic analyzer. As shown in Fig. 1, the automatic analyzer mainly includes a specimen loading section 11, a specimen dispensing mechanism 18, a reagent storage section 12, a reagent dispensing mechanism 19, a reaction section 13, a stirring mechanism 14, a measurement section 15, and a washing section 16, and the operation of each section is controlled by an analyzer control section 23.

[0012] The reaction unit 13 has a rotatable reaction disk, and reaction vessels 6 are arranged circumferentially on the reaction disk. The reaction unit 13 also has a thermostatic bath (water bath) that holds thermostatic water 8 at a specified temperature, and the thermostatic water 8 circulating in the thermostatic bath comes into contact with the reaction vessels 6, thereby maintaining the reaction vessels 6 at a predetermined temperature (see FIG. 2). In this embodiment, the thermostatic water 8 is used as the liquid that transmits ultrasound, but water other than thermostatic water or a liquid other than water may also be used.

[0013] The specimen dispensing mechanism 18 aspirates the amount of specimen 17 required for analysis from the specimen mounting section 11 and dispenses the aspirated specimen 17 into the reaction vessel 6 (reaction cell) at the specimen dispensing position 20. Meanwhile, the reagent dispensing mechanism 19 aspirates the amount of reagent required for analysis from the reagent storage section 12 and dispenses the aspirated reagent into the reaction vessel 6 at the reagent dispensing position 21.

[0014] The reaction vessel 6 into which the specimen 17 and reagent have been discharged is moved to the stirring position 22 by the rotation of the reaction disk, and then stirred by ultrasonic waves emitted from the ultrasonic element of the stirring mechanism 14. The specimen 17 stirred by the stirring mechanism 14 is subjected to component analysis in the measurement unit 15. After the analysis is completed, the reaction vessel 6 is washed in the washing unit 16 and can be reused for another analysis.

[0015] <Stirring mode> Fig. 2 is a diagram showing a schematic configuration of the stirring mechanism in the stirring mode (normal mode). As shown in Fig. 2, the stirring mechanism 14 is provided on the outer periphery of the reaction unit 13 (constant temperature bath), and mainly includes a piezoelectric element 4, an electrode 5, a power supply unit 2, an electrode selector 3, and a stirring mechanism control unit 1.

[0016] The piezoelectric element 4 is attached to the side wall of the thermostatic bath, etc., and emits ultrasonic waves. The electrodes 5 drive the piezoelectric element 4 when a voltage is applied, and multiple electrodes 5 are arranged in a vertical direction. The power supply unit 2 is composed of an amplifier that applies voltage to the electrodes 5. The electrode selector 3 is connected to the multiple electrodes 5 and selects the electrode 5 to which voltage should be applied. The stirring mechanism control unit 1 controls the operation of the power supply unit 2 and the electrode selector 3.

[0017] In the stirring mode, a mixture 7 of a specimen and a reagent is contained in the reaction vessel 6, and the outside of the reaction vessel 6 (between the reaction vessel 6 and the piezoelectric element 4) is filled with constant-temperature water 8. In this state, the stirring mechanism control unit 1 selects one or more electrodes 5 in appropriate positions based on the liquid level (of the mixture 7) detected in advance, and controls the power supply unit 2 and electrode selector 3 to apply a voltage to the selected electrodes 5. The electrode 5 to which the voltage is applied drives the piezoelectric element 4 according to the voltage value, and ultrasonic waves are emitted from the piezoelectric element 4. The ultrasonic waves propagate to the reaction vessel 6 via the constant-temperature water 8, and the mixture 7 in the reaction vessel 6 is stirred.

[0018] In this embodiment, a configuration will be described in which multiple electrodes 5 are attached to a common piezoelectric element 4, and ultrasonic waves are generated by applying a voltage to each electrode 5, but a configuration in which multiple piezoelectric elements are used and each piezoelectric element is driven by applying a voltage may also be used. In either case, it can be considered that ultrasonic waves are generated by having multiple ultrasonic elements and applying a voltage to each ultrasonic element. Furthermore, in this embodiment, an example in which five electrodes are provided will be described, but the number of electrodes is not limited to five.

[0019] <Location measurement mode> Here, when installing or performing maintenance on the stirring mechanism 14 or reaction unit 13, the relative position between the stirring mechanism 14 (electrode 5) and the reaction vessel 6 may deviate from the reference position assumed at the time of design. If the relative position between the reaction vessel 6 and the ultrasonic element changes, the stirring performance of the stirring mechanism 14 also changes, which affects the analytical accuracy. Therefore, it is required to position the stirring mechanism 14 and the reaction unit 13 with high precision during installation, etc. Therefore, in this embodiment, a position measurement mode can be executed to measure the relative position between the stirring mechanism 14 and the measurement object (reaction vessel 6) on the reaction unit 13 side.

[0020] When the position measurement mode is executed, for example, a service person or operator removes the wiring connecting each electrode 5 to the electrode selector 3 and the wiring connecting the stirring mechanism control unit 1 to the power supply unit 2 and the electrode selector 3. After that, the service person or the like installs a waveform control unit 32 (phase control unit), amplifier 33, detection unit 39, calculation unit 40, memory unit 41, and display unit 42 as the stirring mechanism 14, in place of the power supply unit 2 and electrode selector 3. At this time, each electrode 5 is connected to the amplifier 33 and detection unit 39 via wiring. By switching the wiring between the stirring mechanism control unit 1 and each electrode 5 between the stirring mode (normal mode) and the position measurement mode (installation mode, etc.), it is possible to prevent power from being consumed by unnecessary circuits.

[0021] Alternatively, instead of changing the wiring, the circuit used in the stirring mode and the circuit used in the position measurement mode may be connected in parallel, and a switch may be used to switch between the circuits for each mode. This configuration not only allows for positioning during installation, but also enables periodic (for example, once a day) position checks while the automatic analyzer is in operation.

[0022] Next, the configuration of the stirring mechanism 14 in the position measurement mode (positioning) will be described. Fig. 3 is a schematic diagram showing the state of the stirring mechanism when ultrasonic waves are emitted for position measurement, and Fig. 4 is a schematic diagram showing the state of the stirring mechanism when reflected waves of ultrasonic waves emitted for position measurement are detected. Here, an example will be described in which the height position of the bottom surface of the reaction vessel 6 relative to the ultrasonic elements of the stirring mechanism 14 is measured.

[0023] As shown in Figures 3 and 4, the stirring mechanism 14 mainly includes an amplifier 33, a piezoelectric element 4, an electrode 5, and a stirring mechanism control unit 1, as well as a waveform control unit 32, a detection unit 39, a calculation unit 40, a memory unit 41, and a display unit 42.

[0024] Waveform control unit 32 controls the waveform (including the phase) of the voltage applied by amplifier 33 to electrode 5 for each electrode 5. Detection unit 39 detects electrical signals generated from electrode 5 that receive reflected waves generated when ultrasonic waves are reflected by the object to be measured (the bottom surface of reaction vessel 6). Calculation unit 40 measures the relative position of stirring mechanism 14 (ultrasonic elements) and the object to be measured (the bottom surface of reaction vessel 6) based on electrical signals related to reflected waves detected via multiple ultrasonic elements in response to ultrasonic waves emitted from the multiple ultrasonic elements. Memory unit 41 stores the measurement results of calculation unit 40, and display unit 42 displays the measurement results of calculation unit 40.

[0025] Next, the operation of the stirring mechanism 14 in the position measurement mode (positioning) will be described.

[0026] First, the waveform control unit 32 generates a waveform (including phase) signal under the conditions specified by the stirring mechanism control unit 1. At this time, the waveform control unit 32 controls the phase of the ultrasonic waves emitted from the ultrasonic elements located at a height farther from the predetermined position so that it advances more than the phase of the ultrasonic waves emitted from the ultrasonic elements located at a height closer to the predetermined position. Note that the predetermined position is the reference position of the reaction unit 13 (bottom surface of the reaction vessel 6) relative to the stirring mechanism 14 (ultrasonic elements) that is determined at the time of design as a condition that can guarantee stirring performance.

[0027] Next, the amplifier 33 amplifies the waveform signal generated by the waveform control unit 32 to a power level sufficient to drive the ultrasonic elements, and supplies the amplified signals as phase-shifted driving electric signal waveforms 34 to the plurality of electrodes 5. The plurality of electrodes 5 then drive the piezoelectric elements 4 in accordance with the respective driving electric signal waveforms 34 to generate ultrasonic waves.

[0028] Ultrasonic waves (waves shown by dotted lines in FIG. 3) emitted from multiple ultrasonic elements gradually converge to form a composite wave 35 (wave shown by solid lines in FIG. 3), forming a focal point at a predetermined position (position indicated by the tip of the arrow in FIG. 3). Note that, since the height position of the bottom surface of the reaction vessel 6 is the object of measurement, it is sufficient that the focal point is formed at the reference height of the bottom surface of the reaction vessel 6, and the horizontal position of the focal point does not have to be the center of the reaction vessel 6.

[0029] Here, ultrasonic waves are reflected at positions where a difference in acoustic impedance occurs, depending on the magnitude of that difference. In other words, ultrasonic waves are mainly reflected at gas-liquid interfaces, solid-liquid interfaces, and gas-solid interfaces. Although it is possible to detect the reflected wave using only an ultrasonic wave emitted from a single ultrasonic element, the intensity of the reflected wave is weak, so the detection accuracy is not high.

[0030] However, if a focal point is formed by the composite wave 35 and the focal point is positioned at the interface, the ultrasonic wave is largely reflected at the interface. The reflected wave 36 at this time spreads spherically with a large amplitude, as shown in FIG. 4, and reaches multiple ultrasonic elements arranged in the vertical direction. The intensity of the reflected wave reaching each ultrasonic element is relatively strong, resulting in high detection accuracy. Furthermore, because there is a time lag between the time the reflected wave reaches each ultrasonic element, there is also a difference in the time at which the reflected wave is converted into an electrical signal at each electrode 5. Therefore, as shown in FIG. 4, received electrical signal waveforms 37 with a phase shift are sent from each electrode 5 to a detection unit 39. The detection unit 39 transmits information about the amplitude, phase, and other information about the received electrical signal waveforms 37 acquired from each electrode 5 to a calculation unit 40.

[0031] The calculation unit 40 calculates the reflectivity of the ultrasonic waves at the focal position based on the conditions specified by the stirring mechanism control unit 1 and the information on the reflected waves received from the detection unit 39. Here, the memory unit 41 stores the reflectivity of the ultrasonic waves at each position around the reaction vessel 6, which has been acquired in advance. Therefore, the calculation unit 40 can identify the relative position of the bottom of the reaction vessel 6 by comparing the reflectivity stored in the memory unit 41 with the reflectivity that matches the actually calculated reflectivity.

[0032] The calculation unit 40 may perform position measurement by a method other than the above. For example, the calculation unit 40 may calculate another physical quantity instead of calculating the reflectance. The calculation unit 40 may also compare a physical quantity calculated based on the electrical signal actually detected by the detection unit 39 with a physical quantity expected when the reaction vessel 6 is at the reference position, and measure the degree of deviation from the reference position based on the difference.

[0033] Furthermore, if the acoustic impedance of the mixed liquid 7 is close to that of the reaction vessel 6, there is a possibility that the accuracy of measuring the position of the reaction vessel 6 may be reduced. In such a case, the position measurement mode may be performed in an empty state where the mixed liquid 7 is not present in the reaction vessel 6 (a state where the reaction vessel 6 is filled only with a gas such as air).

[0034] The relative position (deviation from the reference position) of the bottom surface of the reaction vessel 6 measured by the calculation unit 40 is stored in the memory unit 41 and is also displayed on the display unit 42. The service person or the like manually adjusts the position of the ultrasonic element or the reaction vessel 6 while checking the display content of the display unit 42. In this case, an output unit (speaker) that outputs the measurement results by the calculation unit 40 as sound may be provided separately from the display unit 42. The output unit changes the frequency or amplitude of the sound emitted depending on the degree of deviation from the reference position, allowing the service person or the like to focus their gaze on the object to be positioned, improving work efficiency.

[0035] Furthermore, the position of the ultrasonic element or the reaction vessel 6 may be determined by a separately provided actuator rather than manually. Positioning is possible when the actuator automatically moves the ultrasonic element or the reaction vessel 6 according to the deviation from the reference position. Furthermore, instead of positioning by the actuator, the stirring performance may be automatically adjusted by reflecting information on the relative position in the selection of the ultrasonic element to be oscillated in the stirring mode or in the waveform of the voltage to be applied to the selected ultrasonic element.

[0036] The position measurement mode may be performed not only at the time of installation or maintenance, but also periodically (once a year, for example) when changes over time are expected. In particular, when positioning and the like can be performed automatically, the position measurement mode may be performed at short intervals, such as once a day or after each stirring operation. For example, each time a predetermined number of reaction vessels 6 are stirred, the relative positions of the reaction vessels 6 may be read from the memory unit 41, and the positions of the ultrasonic elements, etc. may be automatically adjusted.

[0037] <Effects of this embodiment> The effects of the automatic analyzer according to this embodiment will be described below.

[0038] The pitch of multiple electrodes arranged in the height direction is usually about 1 mm. Therefore, in the conventional method of measuring electrical impedance by generating ultrasonic waves only from specific electrodes, the accuracy of measuring the position of the liquid level, etc. is only about 1 mm, which is the electrode pitch.

[0039] On the other hand, in the method of this embodiment, voltage is applied to all ultrasonic elements simultaneously and the reflected waves are detected by each ultrasonic element, enabling highly accurate position measurement regardless of the electrode pitch. In particular, by controlling the phase of ultrasonic waves emitted from multiple ultrasonic elements so that a focus is formed at the reference position of the measurement object, the intensity (amplitude) of the reflected waves from the measurement object can be increased, significantly improving the resolution when detecting the reflected waves at each ultrasonic element. Therefore, it is possible to measure even slight deviations (e.g., 0.1 mm or less) in the relative position between the stirring mechanism 14 (ultrasonic elements) and the reaction unit 13 (bottom surface of the reaction vessel 6). In other words, more accurate positioning is possible, ensuring high stirring performance by the stirring mechanism 14 and maintaining high analytical accuracy.

[0040] The present invention is not limited to the above-described embodiment, and includes various modifications. For example, in the above-described embodiment, the height (vertical position) of the bottom surface of the reaction vessel 6 is measured in the position measurement mode, but the horizontal position of the reaction vessel 6 may also be measured. Furthermore, the object to be measured is not limited to the reaction vessel 6, but may also be the mixed liquid 7 contained in the reaction vessel 6, and the electrode 5 to which the voltage should be applied in the stirring mode may be selected using information on the liquid level height measured in the position measurement mode.

[0041] Furthermore, in the above-described embodiment, the position is measured by a single ultrasonic oscillation and detection, but more detailed position information can be obtained by multiple oscillations and detections. For example, the waveform control unit 32 may control the focal point to change (scan) in the vertical or horizontal direction, and the calculation unit 40 may compare the actually calculated reflectance for each focal point. This allows the position coordinates of each boundary where the difference in acoustic impedance becomes large to be identified with high accuracy, and therefore, for example, it is possible to output an image of the positional relationship of the entire reaction vessel 6 on the display unit 42. [Explanation of symbols]

[0042] 1...Stirring mechanism control section, 2...Power supply section, 3...Electrode selector, 4...Piezoelectric element, 5...Electrode, 6...Reaction vessel, 7...Mixed liquid, 8...Constant temperature water, 11...Sample placement section, 12...Reagent storage section, 13...Reaction section, 14...Stirring mechanism, 15...Measurement section, 16...Cleaning section, 17...Sample, 18...Sample dispensing mechanism, 19...Reagent dispensing mechanism, 20...Sample discharge position, 21...Reagent discharge position, 22...Stirring position, 23...Analyzer control section, 32...Waveform control section, 33...Amplifier, 34...Driving electrical signal waveform, 35...Synthesized wave, 36...Reflected wave, 37...Received electrical signal waveform, 39...Detection section, 40...Calculation section, 41...Memory section, 42...Display section

Claims

1. In an automatic analyzer having a stirring mechanism that stirs specimens and reagents by ultrasonic waves, The stirring mechanism includes: A plurality of ultrasonic elements that emit the ultrasonic waves; an amplifier that applies a voltage to the ultrasonic element; a detection unit that detects an electrical signal generated from the ultrasonic element that receives a reflected wave generated by the ultrasonic wave being reflected by a measurement object; and a calculation unit that measures the relative position between the stirring mechanism and the object to be measured based on the electrical signals related to the reflected waves detected via the plurality of ultrasonic elements in response to the ultrasonic waves emitted from the plurality of ultrasonic elements.

2. The automatic analyzer according to claim 1, The automatic analyzer further comprises a phase control unit that controls the phase of the voltage applied by the amplifier to each of the ultrasonic elements for each of the ultrasonic elements.

3. The automatic analyzer according to claim 2, The ultrasonic waves emitted from the plurality of ultrasonic elements form focal points at predetermined positions.

4. The automatic analyzer according to claim 3, The plurality of ultrasonic elements are arranged in a height direction, The phase control unit controls the phase of the ultrasound emitted from the ultrasound element located at a height farther from the predetermined position so that the phase of the ultrasound emitted from the ultrasound element located at a height closer to the predetermined position is more advanced than the phase of the ultrasound emitted from the ultrasound element located at a height closer to the predetermined position.

5. The automatic analyzer according to claim 3, the measurement object is a reaction vessel into which the specimen and the reagent are dispensed, the predetermined position is a reference position of the reaction vessel with respect to the stirring mechanism, The automatic analyzer is characterized in that the calculation unit measures the deviation from the reference position by comparing a physical quantity calculated based on the actually detected electrical signal with the physical quantity expected when the reaction vessel is in the reference position.

6. The automatic analyzer according to claim 5, further comprising an output unit that outputs the measurement result by the calculation unit, The automatic analyzer is characterized in that the output unit changes the frequency or amplitude of the sound it emits depending on the degree of deviation from the reference position.

7. The automatic analyzer according to claim 5, further comprising an actuator that moves the stirring mechanism or the reaction vessel; The automatic analyzer is characterized in that the actuator automatically moves the stirring mechanism or the reaction vessel in accordance with a deviation from the reference position.

8. The automatic analyzer according to claim 3, the measurement object is a reaction vessel into which the specimen and the reagent are dispensed, The plurality of ultrasonic elements are arranged in a height direction, the phase control unit controls the focal point to scan in a height direction; The automatic analyzer is characterized in that the calculation unit measures the position of the bottom surface of the reaction vessel relative to the stirring mechanism by comparing the physical quantity calculated based on the actually detected electrical signal for each focus.

9. The automatic analyzer according to claim 1, The automatic analyzer is characterized in that the amplifier applies the voltage to all of the ultrasonic elements simultaneously.

10. A position measurement method for an automatic analyzer having an agitation mechanism that agitates a specimen and a reagent by ultrasonic waves, comprising: An amplifier applies a voltage to a plurality of ultrasonic elements to generate ultrasonic waves from the plurality of ultrasonic elements; a step in which a detection unit detects an electrical signal generated from the ultrasonic element that receives a reflected wave generated when the ultrasonic wave is reflected by a measurement object; a step in which a calculation unit measures the relative position between the stirring mechanism and the object to be measured based on the electrical signals related to the reflected waves detected via the plurality of ultrasonic elements.

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