JP2015199037A - Agitation device and automatic analyzer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an agitation device and an automatic analyzer capable of improving agitation efficiency and measurement precision, and in which, lead is not used.SOLUTION: A piezoelectric transducer 51 is oscillated by application of voltage. A holding part 52 is coupled to the piezoelectric transducer 51. A spacer 53 is attached to the holding part 52. A blade 55 is attached to the spacer 53 and agitates a solution. The piezoelectric transducer 51 includes a piezoelectric material having an ABOtype perovskite structure, the piezoelectric material includes at least one kind of bismuth and potassium as an A site chemical element.

Description

  Embodiments described herein relate generally to a stirring device and an automatic analyzer.

  The automatic analyzer is an apparatus that automatically and quantitatively evaluates serum components of multiple samples and multiple items, and is currently widely used in clinical tests. In quantitative evaluation, a sample separated from blood is discharged into a reaction tube, a reagent corresponding to the measurement item is discharged into the reaction tube, the sample and the reagent in the reaction tube are stirred with a stirrer, and the reaction liquid in the reaction tube is compared. This is done in the order of color measurement. It is necessary to mix the specimen and the reagent uniformly in as short a time as possible. The volume of the reaction tube used for the automatic analyzer is as small as several hundred μl. As a method for stirring the reaction solution in such a small capacity reaction tube, conventionally, the stirring rod has been rotated by a motor or a magnet. However, in this method, since only the bottom part in the reaction tube is stirred, there is a drawback that the effect of stirring is difficult to be transmitted to the upper part in the reaction tube, and the stirring time becomes long. In this method, it was considered to increase the number of rotations of the motor in order to shorten the time. However, as the number of rotations increased, bubbles were generated in the reaction solution or bubbles were entrained, and the reaction solution overflowed or scattered from the reaction tube depending on the shape and size of the reaction tube. In addition, bubbles remaining in the reaction tube cause a measurement error in subsequent colorimetric measurement.

  In order to solve these problems, a stirring device is used in which a flexible metal piece called a blade is connected to a bimorph piezoelectric vibrator directly or indirectly via a spacer (Patent Document 1, Patent). Reference 2 and Non-Patent Document 1). According to this stirring device, the stirring efficiency can be improved by vibrating the blade in the secondary mode.

Japanese Patent No. 3135605 Japanese Patent No. 3756296

Hideo Oya, 4 others, “Development of a piezoelectric bimorph stirrer for automatic analyzers”, Denki Theory C, Vol. 122, No. 9, pp. 1672-1678, 2002

  The object is to provide a stirrer and an automatic analyzer that do not use lead.

The stirring device according to the present embodiment includes a vibrating portion that vibrates upon application of a voltage, a holding portion connected to the vibrating portion, a spacer attached to the holding portion, and a solution attached to the spacer. And a vibrating device including a piezoelectric material having an ABO ₃ type perovskite structure, wherein the piezoelectric material is at least one of bismuth and potassium as an A-site element. It is characterized by including.

The figure which shows the structure of the automatic analyzer which concerns on this embodiment. The schematic of the front of the stirring element of the stirring part which concerns on this embodiment. The schematic of the AA cross section of the stirring bar of FIG. FIG. 3 is a schematic cross-sectional view of the piezoelectric vibrator of FIG. 2. The figure which shows schematically the electric system which concerns on the vibration of the stirring part of FIG. The figure which shows typically the stirring element in a primary vibration mode. The figure which shows the stirrer in a secondary vibration mode typically. The figure which shows the graph which showed the frequency dependence of the amplitude of the front-end | tip of the braid | blade of the stirring element which concerns on this embodiment, and the stirring element which concerns on a prior art example. The figure for demonstrating the evaluation method of the stirring performance which concerns on this embodiment. The figure which shows a mode that the motion of the solution in the reaction tube under stirring which was not foaming was image | photographed with the high-speed camera. The figure which shows a mode that the movement of the solution in the reaction tube under stirring in which the foaming has arisen was image | photographed with the high-speed camera. The figure for comparing the vibration node of the stirring bar which concerns on this embodiment in the secondary mode, and the vibration node of the stirring bar which concerns on a prior art example. FIG. 5 is a schematic configuration diagram of another piezoelectric vibrator according to the embodiment.

  As a piezoelectric vibrator in a conventional stirring device, a piezoelectric material using lead represented by PZT (lead zirconate titamate) is used. However, in order to eliminate the influence of lead on the environment and organisms, products that do not use lead are desired. Further, there is a strong demand for shortening the stirring time, and further shortening is desired. It is also desired to reduce the amount of blood collected in order to reduce the burden on the patient. When the amount of the sample liquid is reduced in the existing stirring device, foaming is likely to occur in the reaction solution. Bubbles generated in the reaction solution tend to remain on the inner surface of the reaction tube, and increase measurement errors related to optical measurement such as colorimetric inspection.

  Hereinafter, a stirring device and an automatic analyzer according to the present embodiment will be described with reference to the drawings.

  FIG. 1 is a diagram showing a configuration of an automatic analyzer 1 according to the present embodiment. As shown in FIG. 1, the automatic analyzer 1 includes an analysis mechanism 2, an analysis mechanism control unit 3, an analysis unit 4, a display unit 5, an operation unit 6, a storage unit 7, and a system control unit 8.

  The analysis mechanism 2 operates according to control by the analysis mechanism control unit 3. The analysis mechanism 2 is provided in the housing of the automatic analyzer. For example, as shown in FIG. 1, the analysis mechanism 2 includes a reaction disk 11, a sample disk 13, a first reagent container 15, a second reagent container 17, a sample arm 19-1, a sample probe 21-1, and a first reagent arm. 19-2, the first reagent probe 21-2, the second reagent arm 19-3, the second reagent probe 21-3, the stirring unit 23, the optical measurement unit 25, and the washing unit 27 are mounted.

  The reaction disk (holding mechanism) 11 can hold a plurality of reaction tubes 31 arranged on the circumference. The reaction disk 11 is alternately rotated and stopped at predetermined time intervals. The sample disk 13 is disposed in the vicinity of the reaction disk 11. The sample disk 13 can hold a sample container 33 containing a specimen. The sample disk 13 rotates so that the sample container 33 containing the sample to be dispensed is disposed at the sample inhaling position. The first reagent storage 15 holds a plurality of first reagent containers 35 in which a first reagent that selectively reacts with a measurement item of a sample is accommodated. The 1st reagent storage 15 rotates so that the 1st reagent container 35 in which the 1st reagent of the dispensing object was stored may be arranged in the 1st reagent inhalation position. The second reagent storage 17 is disposed in the vicinity of the reaction disk 11. The second reagent store 17 holds a plurality of second reagent containers 37 in which a second reagent corresponding to the first reagent is accommodated. The 2nd reagent storage 17 rotates so that the 2nd reagent container 37 in which the 2nd reagent of dispensing object was stored may be arranged in the 2nd reagent inhalation position.

  A sample arm 19-1 is disposed between the reaction disk 11 and the sample disk 13. A sample probe 21-1 is attached to the tip of the sample arm 19-1. The sample arm 19-1 supports the sample probe 21-1 so as to be movable up and down. The sample arm 19-1 supports the sample probe 21-1 so as to be rotatable along an arcuate rotation locus. The rotation trajectory of the sample probe 21-1 passes through the sample suction position on the sample disk 13 and the sample discharge position on the reaction disk 11. The sample probe 21-1 sucks the specimen from the sample container 33 disposed at the sample suction position on the sample disk 13 and discharges the specimen to the reaction tube 31 disposed at the discharge position on the reaction disk 11.

  A first reagent arm 19-2 is arranged in the vicinity of the outer periphery of the reaction disk 11. A first reagent probe 21-2 is attached to the tip of the first reagent arm 19-2. The first reagent arm 19-2 supports the first reagent probe 21-2 so as to be movable up and down. The first reagent arm 19-2 supports the first reagent probe 21-2 so as to be rotatable along an arcuate rotation locus. The rotation locus of the first reagent probe 21-2 passes through the first reagent suction position on the first reagent storage 15 and the first reagent discharge position on the reaction disk 11. The first reagent probe 21-2 sucks the first reagent from the first reagent container 35 arranged at the first reagent suction position on the first reagent storage 15, and puts it in the first reagent discharge position on the reaction disk 11. The first reagent is discharged into the arranged reaction tube 31.

  Between the reaction disk 11 and the second reagent storage 17, a second reagent arm 19-3 is arranged. A second reagent probe 21-3 is attached to the tip of the second reagent arm 19-3. The second reagent arm 19-3 supports the second reagent probe 21-3 so as to be movable up and down. The second reagent arm 19-3 supports the second reagent probe 21-3 so as to be rotatable along an arcuate rotation locus. The turning locus of the second reagent probe 21-3 passes through the second reagent suction position on the second reagent storage 17 and the second reagent discharge position on the reaction disk 11. The second reagent probe 21-3 sucks the second reagent from the second reagent container 37 arranged at the second reagent suction position on the second reagent storage 17 and puts it at the second reagent discharge position on the reaction disk 11. The second reagent is discharged into the arranged reaction tube 31.

  A stirring unit 23 is disposed near the outer periphery of the reaction disk 11. The stirrer 23 is provided with a stirrer holding mechanism (support unit) 23-1 and a stirrer 23-2. The stirrer holding mechanism 23-1 supports the stirrer 23-2 so as to be movable up and down. The stirrer 23-2 is lowered into the reaction tube 31 arranged at the stirring position on the reaction disk 11 by the stirrer holding mechanism 23-1. After the stirring bar 23-1 is lowered, the stirring unit 23 vibrates the stirring bar 23-2 to mix the sample and the first reagent in the reaction tube 31, or the sample, the first reagent, and the second reagent. Stir the mixture. Hereinafter, these solutions are referred to as reaction solutions. Moreover, the stirring part 23 wash | cleans the stirring element 23-2 by injecting a washing | cleaning liquid to the stirring element 23-2 in the predetermined timing after completion | finish of stirring. At this time, the stirring unit 23 vibrates the stirring bar 23-2 and shakes off the cleaning liquid adhering to the stirring bar 23-2.

  An optical measurement unit 25 is provided in the vicinity of the reaction disk 11. The optical measurement unit 25 operates according to control by the analysis mechanism control unit 3. Specifically, the optical measurement unit 25 includes a light source 210 and a detector 220. The light source 210 irradiates light toward the reaction solution in the reaction tube 31 at the photometric position in the reaction disk 11. The detector 220 is disposed at a position facing the light source across the reaction tube 31 at the photometric position. The detector 220 detects light irradiated from the light source and transmitted through the reaction tube 31 and the reaction liquid, light reflected by the reaction tube 31 and the reaction liquid, or light scattered by the reaction tube 31 and the reaction liquid. The detector 220 generates data representing a measurement value corresponding to the detected light intensity (hereinafter referred to as photometry data). The generated photometric data is supplied to the analysis unit 4.

  A cleaning unit 27 is provided on the outer periphery of the reaction disk 11. The cleaning unit 27 operates according to control by the analysis mechanism control unit 3. Specifically, the cleaning unit 27 is equipped with a cleaning nozzle and a drying nozzle. The cleaning unit 27 cleans the reaction tube 31 at the cleaning position of the reaction disk 11 with a cleaning nozzle and dries it with a drying nozzle.

  The analysis mechanism control unit 3 operates each device and mechanism of the analysis mechanism 2 according to control by the system control unit 8. The analysis unit 4 calculates the value of the measurement item for the reaction solution based on the photometric data. Specifically, the analysis unit 4 calculates the absorbance of the reaction solution based on the photometric data, or calculates the turbidity based on the calculated absorbance. The display unit 5 includes a display device such as a CRT display, a liquid crystal display, an organic EL display, or a plasma display. The display unit 5 displays the analysis result by the analysis unit 4. The operation unit 6 receives various commands and information input from an operator via an input device. As the input device, a pointing device such as a mouse or a trackball, a selection device such as a switch button, or an input device such as a keyboard can be used as appropriate. The storage unit 7 stores an operation program of the automatic analyzer 1. The system control unit 8 functions as the center of the automatic analyzer 1. The system control unit 8 reads out the operation program from the storage unit 7 and controls the units 3, 4, 5, and 7 according to the operation program.

  Next, the details of the automatic analyzer 1 according to the present embodiment will be described.

  FIG. 2 is a schematic diagram of the front surface of the stirring bar 23-2 of the stirring unit 23 according to the present embodiment, and FIG. 3 is a schematic diagram of an AA cross section of the stirring bar 23-2 of FIG. The solid line portion in FIG. 2 is a portion that is visible from the outside, and the dotted line portion represents a portion that is not visible from the outside.

  As shown in FIGS. 2 and 3, the stirrer 23-2 has a housing 50. A vibration unit 51, a holding unit 52, and a spacer 53 are accommodated in the housing 50. The vibration unit 51 vibrates upon application of a voltage from a power supply unit (not shown). The vibration unit 51 is composed of a piezoelectric vibrator. The holding part 52 is configured by a metal substrate having a flexible structure. A piezoelectric vibrator 51 is attached to each of the front surface and the back surface of the holding portion 52. That is, the holding part 52 is connected to the piezoelectric vibrator. Hereinafter, the piezoelectric vibrator 51 attached to the front surface is referred to as a front-side vibrator 51-1, and the piezoelectric vibrator 51 attached to the back surface is referred to as a back-side vibrator 51-2. Thus, the holding unit 52, the front-side vibrator 51-1 and the back-side vibrator 51-2 constitute a bimorph piezoelectric vibrator 70. One end of the holding portion 52 is fixed to the housing 50 by a fastener 54-1 such as a screw. A blade 55 is attached to the other end of the holding portion 52 via a spacer 53. A notch is formed in the lower end of the housing 50, and the spacer 53 and the blade 55 are exposed to the outside. The holding portion 52, the spacer 53, and the blade 55 are integrally fixed by a fastener 54-2 such as a screw at the lower portion of the housing 50. The blade 55 is a stirring rod for stirring the reaction solution in the reaction tube 31. Typically, the blade 55 and the holding part 52 are formed of the same metal material. The surface of the blade 55 is coated with a protective coating so that the blade 55 can withstand various liquid solutions in the reaction tube 31. The thickness a of the spacer 53 along the axis of the fastener 54-2 is the distance b between the holding portion 52 on the fastener 54-1 side and the wall surface without the casing 50 in order to avoid contact between the housing 50 and the blade 55. It is preferably designed to be thicker.

FIG. 4 is a schematic cross-sectional view of the piezoelectric vibrator 51. The front-side vibrator and the back-side vibrator have substantially the same configuration. Therefore, in FIG. 4, the front-side vibrator and the back-side vibrator are collectively illustrated as the piezoelectric vibrator 51. As shown in FIG. 4, the piezoelectric vibrator 51 has a piezoelectric body 511 made of a piezoelectric material and an electrode 512 made of an electrode material. The piezoelectric body 511 has a plate shape. Electrodes 512 are formed on the front and back surfaces of the piezoelectric body 511. The piezoelectric vibrator 51 is preliminarily subjected to a polarization process in which a DC voltage is applied between the electrodes 511 to align the direction of the dipole moment of the piezoelectric body. The arrows in the figure indicate the direction of polarization. As the piezoelectric material, a piezoelectric material having an ABO ₃ type perovskite structure containing at least one of bismuth Bi and potassium K as an A site element is used. As an electrode material, a silver Ag baked electrode or a sputter electrode such as chromium Cr / gold Au or titanium Ti / gold Au is used. One of the electrodes 512 is provided so as to face the holding portion 52.

  FIG. 5 is a diagram schematically showing an electrical system related to the vibration of the stirring unit 23. As shown in FIG. 5, the stirring unit 23 includes a power supply unit 60, a piezoelectric vibrator 51 (front-side vibrator 51-1 and back-side vibrator 51-2), and a holding unit 52. The power supply unit 60 uses an AC voltage to be applied to the front-side vibrator 51-1 and the back-side vibrator 51-2 according to control by the analysis mechanism control unit 3, using a voltage from an external power supply (not shown). Occur. The power supply unit 60, the electrode of the front-side vibrator 51-1 and the electrode of the back-side vibrator 51-2 are connected by a conducting wire. As shown in FIG. 5, the piezoelectric vibrator 51-1 and the piezoelectric vibrator 51-2 are bonded to the holding portion (metal substrate) 52 so that the polarization directions are the same. Therefore, the AC voltage generated by the power supply unit 60 is applied in directions opposite to each other with respect to the polarization directions of the front-side vibrator 51-1 and the back-side vibrator 51-2. The front-side vibrator 51-1 and the back-side vibrator 51-2 that have received the application of the alternating voltage vibrate because one of them alternately expands and the other shrinks.

  The holding part 52 vibrates with the vibration of the front-side vibrator 51-1 and the back-side vibrator 51-2. The holding part 52 is restrained by the fastener 54-2 from being excessively shaken or displaced due to its own vibration. The vibration of the holding part 52 is conducted to the blade 55 through the spacer 53, and the tip of the blade 55 vibrates. The reaction liquid in the reaction tube 31 is stirred using the vibration of the tip of the blade 55. The spacer 53 is designed to have an appropriate hardness and weight for controlling the amplitude of vibration at the tip of the blade 55 so as to appropriately stir the liquid in the reaction tube 31. In addition, the hardness of the spacer 53 should just be designed to the hardness which does not absorb the vibration of the holding | maintenance part 52 more than necessary. The amplitude of the vibration at the tip of the blade 53 depends on the peak value and frequency of the AC voltage applied to the front-side vibrator 51-1 and the back-side vibrator 51-2. The amplitude of vibration at the tip of the blade 55 also depends on the physical properties and materials of the piezoelectric material, the weight of the spacer 53 and the fasteners 54-1 and 54-2, and the shape and weight of each component relating to the stirrer 23-2. To do.

  As the frequency of the AC voltage applied to the piezoelectric vibrator 51 is changed, the vibration mode of the stirrer 23-2 changes. FIG. 6 is a diagram schematically showing a stirrer in a primary vibration mode (hereinafter referred to as a primary mode), and FIG. 7 is a diagram of stirring in a secondary vibration mode (hereinafter referred to as a secondary mode). It is a figure which shows a child typically. As shown in FIG. 6, in the primary mode (primary resonance), the bimorph piezoelectric vibrator 70 and the blade 55 vibrate in the same phase. In the primary mode, there are no vibration nodes. As shown in FIG. 7, in the secondary mode (secondary resonance), the bimorph piezoelectric vibrator 70 and the blade 55 vibrate in opposite phases. That is, a vibration node occurs in the secondary mode. In the secondary mode, the touch angle θ at the blade tip increases as compared to the primary mode. Accordingly, in the secondary mode, the solution in the reaction tube can be wound up with a blade as compared with the primary mode, so that the stirring efficiency is good. Therefore, the secondary mode is used for stirring the reaction solution in the reaction tube.

  The power source 60 generates an AC voltage having a frequency at which the blade 55 vibrates in the secondary mode, in other words, an AC voltage having a frequency at which the blade 55 and the bimorph piezoelectric vibrator 70 vibrate in mutually opposite phases. Apply to 51-1 and back-side vibrator 51-2. The frequency of the AC voltage can be arbitrarily set in advance via the operation unit 6 or the like.

As described above, a piezoelectric material having an ABO ₃ type perovskite structure containing at least one of bismuth Bi and potassium K as the A site element is used as the piezoelectric material used in the piezoelectric vibrator according to the present embodiment. That is, the piezoelectric material according to the present embodiment does not contain lead Pb used in existing piezoelectric vibrators. The piezoelectric material according to this embodiment has higher rigidity than existing piezoelectric materials using lead Pb.

  Conventionally, as a piezoelectric material using lead Pb, a piezoelectric material having a perovskite structure using lead Pb as an A-site element has been used. Examples of such a piezoelectric material include Pb (Zr, Ti) O3 (PZT, lead zirconate titamate).

Next, the piezoelectric material will be described in detail. More specifically, the piezoelectric material according to the present embodiment is an ABO ₃ type perovskite structure, and the piezoelectric material includes at least one of bismuth Bi and potassium K as an A site element, and a B site element. As at least one of titanium Ti, niobium Nb, and tantalum Ta. Moreover, the piezoelectric material according to the present embodiment may include an oxide containing manganese Mn, nickel Ni, or niobium Nb as an additive. As such a piezoelectric material, for example, KNbO ₃ (KN), x (Bi _0.5 , Na _0.5 ) TiO ₃ -y (Bi _0.5 , K _0.5 ) TiO ₃ (BNKT), Materials represented by chemical formulas such as x + y = 1, x (Bi _0.5 , Na _0.5 ) TiO ₃ -y (Bi _0.5 , K _0.5 ) TiO ₃ + Mn ₂ O ₃ , x + y = 1 Is mentioned.

Further, the piezoelectric material according to the present embodiment may include at least one of sodium Na, lithium Li, and barium Ba in addition to at least one of bismuth Bi and potassium K as an A site element. As such a piezoelectric material, for example, x (Bi _0.5 , Na _0.5 ) TiO ₃ -y (Bi _0.5 , K _0.5 ) TiO ₃ −zBaTiO ₃ , x + y + z = 1, xKNbO _{3 -yNaNbO 3 -zLiNbO 3, x + y} + z = 1, xKNbO 3 -yNaNbO 3 -zLiTaO 3, x + y + z = material expressed by the chemical formula such as 1 and the like.

Next, the piezoelectric material is exemplified by lead zirconate titanate (PZT), bismuth sodium titanate and barium titanate solid solution (BNBT), barium titanate (BT), and potassium niobate (KN). The physical properties of will be described. PZT is a piezoelectric material containing lead, and BNBT, BT, and KN are piezoelectric materials not containing lead. Consider the frequency constant (frequency constant in the lateral effect) N ₃₁ of the piezoelectric material. In general, N ₃₁ is expressed as N ₃₁ = l · f. l is the length of the piezoelectric body with respect to the vibration direction, and f is the resonance frequency. The frequency constant N _{31 of} PZT is l · f = 1400 m · Hz, the frequency constant N _{31 of} BNBT is l · f = 2300 m · Hz, and the frequency constant N _{31 of} BT is l · f = 2200 m · Hz, KN. The frequency constant N ₃₁ is l · f = 2600 m · Hz. As described above, the lead-free piezoelectric material according to the present embodiment has a higher frequency constant N than the lead-based piezoelectric material such as PZT in relation to higher rigidity than the lead-based piezoelectric material such as PZT. ₃₁ is high. According to the above comparison of numerical values, lead-based piezoelectric materials such as PZT have a frequency constant N ₃₁ generally lower than 2000 m · Hz, and lead-free piezoelectric materials have a frequency constant N ₃₁ generally higher than 2000 m · Hz. That is, the piezoelectric material according to the present embodiment, it is preferable frequency constant N ₃₁ is made of a material is substantially 2000 m · Hz or more.

  Increasing the rigidity of the piezoelectric vibrator 51 produces two main effects according to the present embodiment. As a first effect, since the stirrer 23-2 according to the present embodiment increases the number of vibrations per unit time as compared with the stirrer according to the conventional example, the sample and the reagent in the reaction tube 31 are removed. It can be mixed uniformly in a short time. As a second effect, the stirrer 23-2 according to the present embodiment can suppress foaming during stirring as compared with the stirrer according to the conventional example, thereby reducing measurement error due to foaming. What can be done. Hereinafter, the first effect and the second effect will be described in order. First, the 1st main effect which concerns on this embodiment is demonstrated.

FIG. 8 is a graph showing the frequency dependence of the amplitude of the blade tip of the stirrer 23-2 according to the present embodiment and the stirrer according to the conventional example. Note that the stirrer according to the conventional example has the same configuration as the stirrer according to the present embodiment, and PZT having an ABO ₃ type perovskite structure containing lead Pb in the A site element is used as the piezoelectric material. It has been. The vertical axis of FIG. 8 is defined by the amplitude [mm] of the blade tip, and the horizontal axis is defined by the vibration frequency [Hz] of the blade tip. The solid line in FIG. 8 indicates the stirrer 23-2 according to this embodiment, and the dotted line indicates the stirrer according to the conventional example. The frequency of vibration at the tip of the blade depends on various factors such as the frequency of the AC voltage applied to the piezoelectric vibrator, the physical properties of the piezoelectric vibrator, and the material of the piezoelectric vibrator. In FIG. 8, the frequency of the vibration at the tip of the blade is changed by changing the frequency of the AC voltage applied to the piezoelectric vibrator.

  As shown in FIG. 8, when the frequency of the AC voltage applied to the piezoelectric vibrator is increased from a low frequency wave to a high frequency, the vibration mode of the stirrer changes from the primary mode to the secondary mode around a certain frequency. To metastasize. In the case of the stirrer 23-2 according to the present embodiment, the amplitude of the blade tip becomes a maximum value within the primary mode range and then becomes a maximum value within the secondary mode range due to a resonance phenomenon. The frequency at which the resonance phenomenon occurs is called the resonance frequency. In the vicinity of the resonance frequency, the amplitude of the blade tip increases rapidly. In the case of the stirrer according to the conventional example, the amplitude of the tip of the blade becomes a maximum value on the lower frequency side than the stirrer 23-2 according to the present embodiment within the primary mode range, and then within the secondary mode range In FIG. 5, the maximum value is obtained on the lower frequency side than the stirrer 23-2 according to the present embodiment. The amplitude value of the secondary mode is approximately one half of the amplitude value of the primary mode. Thus, since the stirrer 23-2 according to the present embodiment uses a piezoelectric material having rigidity compared to the stirrer according to the conventional example, the resonance frequency is shifted to the high frequency side. By using the piezoelectric material according to the present embodiment, the stirring unit 23 according to the present embodiment can increase the vibration frequency as compared with the stirring unit according to the conventional example under the condition that the amplitude of the tip of the blade is the same. it can.

  From the viewpoint of stirring efficiency, it is desirable that the vibration frequency at the tip of the blade 55 is higher. However, the frequency range in which the amplitude changes suddenly as the frequency changes is not preferable for the AC voltage applied to the piezoelectric vibrator 51 from the viewpoint of securing a stable amplitude. From this point of view, the analysis mechanism control unit 3 may set the frequency of the alternating voltage generated by the power supply unit 60 in a frequency range in which the amplitude change at the tip of the blade 55 accompanying the frequency change is relatively small. For example, it may be set to a frequency indicating an amplitude that is 2/3 or less of the amplitude peak that vibrates in the secondary mode. For example, it may be set to a frequency indicating an amplitude that is ½ or less of an amplitude peak that vibrates in the secondary mode. That is, the power supply unit 60 can apply an AC voltage having a frequency at which the blade vibrates in the secondary mode to the piezoelectric vibrator 51.

  From the viewpoint of physical limitations between the inner walls of the reaction tube 31, the amplitude of the tip of the blade 55 must be smaller than the distance between the inner walls of the reaction tube 31. From this point of view, the analysis mechanism control unit 3 may set the frequency of the AC voltage generated by the power supply unit 60 to a frequency range in which the amplitude of the tip of the blade 55 is smaller than the distance between the inner walls of the reaction tube 31. Here, the distance between the inner walls is the diameter of the inner wall of the circle when the cross section of the reaction tube 31 is circular, and the short axis of the inner wall when the cross section of the reaction tube 31 is elliptical.

  Typically, the analysis mechanism control unit 3 sets the frequency of the AC voltage generated by the power supply unit 60 so that the amplitude of the tip of the blade 55 is smaller than the distance between the inner walls of the reaction tube 31, and the blade 55 is associated with the frequency change. Is set to a frequency range in which the amplitude change at the tip of the filter is relatively small. As a result, the power supply unit 60 applies an AC voltage belonging to a frequency range in which the amplitude of the tip of the blade 55 is smaller than the distance between the inner walls of the reaction tube 31 and the amplitude change of the tip of the blade 55 accompanying the frequency change is small. 51 can be applied.

  The evaluation result of the stirring performance in the case where the stirrer 23-2 according to the present embodiment and the stirrer according to the conventional example are vibrated in the secondary mode is shown. FIG. 9 is a diagram for explaining a method for evaluating the stirring performance. As shown in FIG. 9, a saline solution was put in the reaction tube 31, and a dye solution (Evans Blue) was put on the saline solution so as to form two layers. Two such reaction tubes were prepared. The solutions in the two reaction tubes 31 were respectively stirred with the stirrer 23-2 according to this embodiment and the stirrer according to the conventional example. The chromaticity was measured at five measurement points in the reaction tube 31. There were five measurement points A to E, which were set at different heights. The higher the value, the higher the transparency of the solution. Before the stirring started, the chromaticity of the five measurement points had different values depending on the height. However, when stirring is started, the chromaticity of all measurement points approaches the average value of the five chromaticities before stirring and shows a constant value as time passes. When it reaches a certain value, the stirring is completed.

  In the case of the stirrer according to the conventional example, it has been found that the time until the chromaticity becomes constant is longer than in the case of the stirrer 23-2 according to the present embodiment. As described above, when the amplitude of the blade tip is the same as described above, the stirrer 23-2 according to the present embodiment can increase the vibration frequency as compared with the stirrer according to the conventional example. This is considered to be due to the increase in the number of blade vibrations per unit time.

  Next, a second main effect according to the present embodiment (because foaming during stirring can be suppressed, measurement error due to foaming can be reduced) will be described.

  FIGS. 10 and 11 are views showing a state in which the movement of the solution in the reaction tube being stirred is photographed with a high-speed camera. The solution in the reaction tube of FIG. 10 is not foamed, and the reaction of FIG. Foaming occurs in the solution in the tube. In the imaging of FIG. 10, tracer particles are introduced into the solution in the reaction tube. Tracer particles are used to make the flow of the solution in the reaction tube visible. Glass beads were used as the tracer particles.

  The left side of FIG. 10 is an image at rest before the start of stirring, the middle is an image during stirring, and the right is an image at rest after the end of stirring. As shown in FIG. 10, when the stirrer is stationary, the tracer particles are precipitated. After starting the stirring of the stirrer, the tracer particles are rolled up over the entire solution in the reaction tube.

  As shown in FIG. 11, when the blade vibrates greatly in the vicinity of the liquid level, the liquid level near the center of the amplitude of the blade falls and air is taken into the liquid to cause foaming. That is, in order to suppress foaming, it is effective to reduce the amplitude near the liquid surface. However, from the viewpoint of stirring efficiency, it is desirable that the blade tip has a large amplitude.

  As described above, the piezoelectric vibrator 51 according to this embodiment has higher rigidity than the piezoelectric vibrator according to the conventional example. Therefore, the position of the vibration node in the secondary mode changes according to the rigidity of the piezoelectric vibrator 51.

  FIG. 12 is a diagram for comparing the vibration node of the stirrer 23-2 according to the present embodiment in the secondary mode with the vibration node of the stirrer according to the conventional example. As shown in FIG. 12, the stirrer according to this embodiment has a vibration node closer to the tip of the blade than the stirrer according to the conventional example. In order to increase the stirring efficiency, the stirrer is lowered by the stirrer holding mechanism 23-1 so that the tip of the blade is positioned near the inner bottom surface of the reaction tube. In the case of a typical liquid amount, the distance from the tip of the blade to the node is longer than the distance from the inner bottom surface of the reaction tube to the liquid surface. Therefore, when the descending amount of the stirrer at the stirring position is the same, the stirrer 23-2 according to the present embodiment is closer to the liquid level of the reaction liquid in the reaction tube than the stirrer according to the conventional example. The stirrer holding mechanism 23-1 can support the blade so that the vibration node of the blade in the secondary mode is positioned near the liquid surface of the solution.

  Further, when the amplitude of the blade tip is set to the same value in the stirrer 23-2 according to this embodiment and the stirrer according to the conventional example, this embodiment does not depend on the amount of the solution in the reaction tube. The amplitude of the stirring bar 23-2 is smaller than that of the conventional stirring bar. Therefore, the stirrer 23-2 according to the present embodiment has a rigidity higher than that of the prior art, and the amplitude of the blade tip is the same as that of the conventional example because the vibration node of the secondary mode is lowered. Even in this case, the amplitude of the blade in the vicinity of the liquid level can be suppressed. Thereby, the stirrer 23-2 according to the present embodiment can suppress foaming due to vibration near the liquid surface as compared with the conventional example, and can reduce measurement errors caused by foaming.

  This is the end of the description of the two main effects according to the present embodiment.

  In the above embodiment, as shown in FIG. 4, the piezoelectric vibrator 51 is composed of one piezoelectric body 511 and two electrodes 512. However, the piezoelectric vibrator 51 according to the present embodiment is not limited to this. For example, when there are two piezoelectric bodies, as shown in FIG. 13, the piezoelectric vibrator 51 ′ includes a first piezoelectric body 511a and a second piezoelectric body 511b that connect the first electrode 512a and the second electrode 512a. You may have the structure laminated | stacked through. The first electrode 512a and the second electrode 512b are arranged and connected every other layer, and are insulated from each other. When the total thickness of the piezoelectric vibrator 51 ′ is the same as that of the piezoelectric vibrator 51 and each piezoelectric vibrator is driven with the same voltage, the voltage applied to the piezoelectric bodies 511 a and 511 b is about twice that of the piezoelectric body 511. Therefore, the amplitude is also doubled. Therefore, with this configuration, it is possible to vibrate the tip of the blade by applying an alternating voltage that is lower than the configuration of FIG. 13 illustrates a piezoelectric vibrator 51 ′ including two piezoelectric bodies 511. However, the present embodiment is not limited to this, and the piezoelectric vibrator 51 ′ according to the present embodiment includes two pieces. The piezoelectric body 511 and the electrode 512 described above may be included.

As described above, the stirring unit 23 according to the present embodiment includes the vibration unit (piezoelectric vibrator) 51, the holding unit (metal substrate) 52, the spacer 53, and the stirring rod (blade) 55. The piezoelectric vibrator 51 vibrates upon application of a voltage. The holding unit 52 holds the piezoelectric vibrator 51. The spacer 53 is attached to the holding part 52. The blade 55 is attached to the spacer 53 and stirs the solution. The piezoelectric vibrator 51 includes a piezoelectric material having an ABO ₃ type perovskite structure, and the piezoelectric material includes at least one of Bi and K as an A site element.

  With the above configuration, a stirrer having higher rigidity than that of a stirrer using lead can be realized. Since the stirrer 23-2 according to the present embodiment increases the number of vibrations per unit time as compared with the stirrer according to the conventional example due to the high rigidity, the sample and the reagent in the reaction tube 31 are removed. It can be mixed uniformly in a short time. Moreover, since the stirring bar 23-2 which concerns on this embodiment can suppress foaming during stirring compared with the stirring bar which concerns on a prior art example, it can reduce the measurement error resulting from foaming.

  Thus, according to the present embodiment, it is possible to provide a stirring device and an automatic analyzer that do not use lead while improving the stirring efficiency and measurement accuracy.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 1 ... Automatic analyzer, 2 ... Analysis mechanism, 3 ... Analysis mechanism control part, 4 ... Analysis part, 5 ... Display part, 6 ... Operation part, 7 ... Memory | storage part, 8 ... System control part, 11 ... Reaction disk, 13 ... Sample disk, 15 ... First reagent compartment, 17 ... Second reagent compartment, 19-1 ... Sample arm, 19-2 ... First reagent arm, 19-3 ... Second reagent arm, 21-1 ... Sample probe, 21-2: First reagent probe, 21-3: Second reagent probe, 23: Stirring unit, 23-1: Stirring member holding mechanism, 23-2: Stirring bar, 25: Optical measuring unit, 27: Washing unit, DESCRIPTION OF SYMBOLS 31 ... Reaction tube, 33 ... Sample container, 35 ... 1st reagent container, 37 ... 2nd reagent container, 50 ... Case, 51 ... Vibrating part (piezoelectric vibrator), 52 ... Holding part (metal substrate), 53 ... Spacer, 54 ... Fastener, 55 ... Stirring bar (blade), 60 ... Power supply, 70 Bimorph piezoelectric vibrator, 511 ... piezoelectric body, 511a ... first piezoelectric body, 511b ... second piezoelectric body, 512 ... electrode, 512a ... first electrode, 512b ... Second electrode.

Claims (10)

A vibrating part that vibrates upon application of a voltage;
A holding part connected to the vibrating part;
A spacer attached to the holding part;
A stirring rod attached to the spacer for stirring the solution;
A stirring device comprising:
The vibrating portion includes a piezoelectric material having an ABO ₃ type perovskite structure, and the piezoelectric material includes at least one of bismuth and potassium as an A site element.
A stirrer characterized by that. A power supply unit that generates an AC voltage applied to the vibrating unit;
The power supply unit can apply an alternating voltage having a frequency at which the stirring bar vibrates in a secondary mode to the vibrating unit.
The stirring device according to claim 1. A power supply unit that generates an AC voltage applied to the vibrating unit;
The frequency of the AC voltage is set so that the amplitude of the tip of the stirring bar is narrower than the distance between the inner walls of the container containing the solution.
The stirring device according to claim 1.   The stirrer according to claim 2, further comprising a support portion that supports the stirrer so that a node of vibration of the stirrer in the secondary mode is positioned in the vicinity of the liquid level of the solution. The holding part has a metal substrate having a plate shape,
The vibration unit includes a first piezoelectric vibrator that is attached to the front surface of the substrate and includes the piezoelectric material, and a second piezoelectric vibrator that is attached to the back surface and includes the piezoelectric material.
The stirring device according to claim 1.   The vibrating portion is a laminated structure in which a plurality of piezoelectric bodies formed of the piezoelectric material are stacked via electrodes formed of an electrode material, the electrodes are connected every other layer, and the electrodes are insulated from each other. The stirring apparatus according to claim 1, comprising:   The stirrer according to claim 1, wherein the piezoelectric material includes at least one of sodium, lithium, and barium in addition to at least one of bismuth and potassium as an A site element.   The stirrer according to claim 1, wherein the piezoelectric material contains at least one of titanium, niobium, and tantalum as a B-site element.   The stirring device according to claim 1, wherein the piezoelectric material does not contain lead as an A-site element. A holding mechanism capable of holding the reaction tube;
A stirring section for stirring the solution contained in the reaction tube;
An optical measurement unit that irradiates the solution contained in the reaction tube with light and detects the irradiated light, and generates data according to the intensity of the detected light;
A calculation unit that calculates a value of a measurement item for the solution based on the data, and an automatic analyzer comprising:
The stirring unit is
A vibrating part that vibrates upon application of a voltage;
A holding part connected to the vibrating part;
A spacer attached to the holding part;
A stirring bar attached to the spacer,
The vibrating portion includes a piezoelectric material having an ABO ₃ type perovskite structure, and the piezoelectric material includes at least one of bismuth and potassium as an A site element.
An automatic analyzer characterized by that.