Automated analyzer

Abstract

Provided is an automatic analysis device capable of detecting that the tip of a probe is in contact with the liquid surface even when the capacitance between a container and the probe is excessively increased. The present invention relates to an automatic analysis device for analyzing a specimen, comprising a container used for containing liquid, a probe used for attracting the liquid, an electrostatic capacity measuring part used for outputting voltage according to the electrostatic capacity between the container and the probe, and a judging part used for judging whether the front end of the probe makes contact with the liquid or not according to the voltage output by the electrostatic capacity measuring part. And a capacitor provided between the probe or the container and the capacitance measurement unit.

Description

Technical Field

[0001] This disclosure relates to an automatic analysis device. Background Technology

[0002] In automated analytical devices that analyze samples such as blood or urine provided by patients, a thin-tube probe is used to attract the reaction solution or other liquid obtained after the sample reacts with reagents. Additionally, a liquid level detection device is provided for the probe to detect whether the tip of the probe is in contact with the liquid surface.

[0003] Patent document 1 discloses an automatic analysis device that includes a liquid level detection device. This liquid level detection device can detect whether the tip of the probe is in contact with the liquid surface based on the voltage output by the electrostatic capacitance between the container containing the liquid and the probe.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2010-185796 Summary of the Invention

[0007] The technical problem that the invention aims to solve

[0008] However, Patent Document 1 does not consider the case where the capacitance between the container and the probe increases excessively. If the capacitance between the container and the probe increases excessively due to the formation of an electric double-layer capacitor, the output voltage will decrease, and even if the tip of the probe is in contact with the liquid surface, it will be falsely detected as not being in contact with the liquid surface.

[0009] Therefore, the object of the present invention is to provide an automatic analysis device that can detect when the probe tip comes into contact with the liquid surface, even when the electrostatic capacitance between the container and the probe becomes excessively large.

[0010] Technical means to solve technical problems

[0011] To achieve the above objectives, the present invention provides an automated analytical device for analyzing samples, characterized in that it includes a container for containing liquid, a probe for attracting the liquid, a capacitance measuring unit for outputting a voltage based on the capacitance between the container and the probe, a determining unit for determining whether the tip of the probe is in contact with the liquid based on the voltage output by the capacitance measuring unit, and a capacitor disposed between the probe or the container and the capacitance measuring unit.

[0012] Invention Effects

[0013] According to the present invention, an automatic analysis device can be provided that can detect when the front end of the detector is in contact with the liquid surface, even when the electrostatic capacitance between the container and the probe becomes excessively large. Attached Figure Description

[0014] Figure 1 This is a schematic diagram illustrating an example of the overall structure of an automated analysis device.

[0015] Figure 2 This is a schematic diagram illustrating an example of the structure of an existing liquid level detection device and the waveform of the output voltage of the electrostatic capacitance measuring unit.

[0016] Figure 3 This is a schematic diagram illustrating an example of the structure of the liquid level detection device of Example 1 and the waveform of the output voltage of the electrostatic capacitance measuring unit.

[0017] Figure 4 This is a schematic diagram illustrating another example of the structure of the liquid level detection device of Example 1.

[0018] Figure 5 This is a schematic diagram illustrating another example of the structure of the liquid level detection device of Example 1.

[0019] Figure 6 This is a schematic diagram illustrating another example of the overall structure of an automated analysis device. Detailed Implementation

[0020] Hereinafter, preferred embodiments of the automatic analysis apparatus according to the present invention will be described with reference to the accompanying drawings. Furthermore, in the following description and drawings, structural elements having the same functional structure are labeled with the same symbols, and repeated descriptions are omitted.

[0021] [Example 1]

[0022] use Figure 1 An example of the overall structure of the automated analysis device will be described. The automated analysis device is used to analyze samples such as blood or urine provided by a patient, and includes a container 1, a probe 4, an analysis unit 6, a control unit 12, and a liquid level detection device 13. Each part will be described below.

[0023] Container 1 is used to contain the reaction solution or other liquid 2 obtained after the sample and reagent react. It is electrically connected to the liquid level detection device 13 via transmission line 1a and functions as one electrode of the liquid level detection device 13. In addition, the container 1 can be moved in the horizontal and vertical directions by means of the container drive unit 3 controlled by the control unit 12.

[0024] The probe 4 is a thin tube that can be inserted into the liquid 2 contained in the container 1 and draw in the liquid 2. The probe 4 is connected to the syringe 10 via flow path 7a, analysis unit 6, and flow path 7b, and draws in the liquid 2 by the action of the piston 11 that moves within the syringe 10. The action of the piston 11 is controlled by the control unit 12. Furthermore, the probe 4 is electrically connected to the liquid level detection device 13 via delivery line 4a, switch 15, and delivery line 4b, and functions as one electrode of the liquid level detection device 13. The switching on and off of the switch 15 is controlled by the control unit 12. In addition, the probe 4 can be moved in both horizontal and vertical directions by using the probe drive unit 5 controlled by the control unit 12.

[0025] The analysis unit 6 analyzes the liquid 2 attracted by the probe 4. Specifically, the liquid 2 is introduced between the electrode 8 (for detecting specified ions) and a reference electrode (not shown), and the potential difference between the two electrodes is measured. The ion concentration in the liquid 2 can be determined based on the measured potential difference. Furthermore, the electrode 8 is not limited to one; the number can be set according to the type of ions detected. The analysis results obtained by the analysis unit 6, such as the ion concentration, are output to the control unit 12 via the transport line 8a.

[0026] The control unit 12 is a computer used to control the actions of each unit and to store or display the results in the analysis unit 6.

[0027] The liquid level detection device 13 operates using power supplied by the power source 14. Based on the voltage output according to the capacitance between the input terminals, it detects whether the tip of the probe 4, which serves as one electrode, is in contact with the surface of the liquid 2. Since the operation of the liquid level detection device 13 can introduce noise into the analysis results of the analysis unit 6, the switch 15 is opened during the analysis process to stop the operation of the liquid level detection device 13, thereby preventing the introduction of noise.

[0028] use Figure 2 The structure of the existing liquid level detection device 13 will be described below. The liquid level detection device 13 includes a capacitance measuring unit 16, a threshold storage unit 18, and a determination unit 17. The capacitance measuring unit 16 outputs a voltage corresponding to the capacitance between the conveyor line 1a connected to the container 1 and the conveyor line 4b connected to the probe 4 via the conveyor line 4a and the switch 15. The threshold storage unit 18 stores a preset threshold. The determination unit 17 compares the output voltage of the capacitance measuring unit 16 with the threshold stored in the threshold storage unit 18 to determine whether the tip of the probe 4 is in contact with the liquid surface of the liquid 2, and outputs the determination result to the control unit 12.

[0029] In other words, the capacitance between container 1 and probe 4 changes with the distance between the tip of probe 4 and the liquid surface. If the tip of probe 4 is close to the liquid surface, the output voltage of capacitance measuring unit 16 increases sharply. Figure 2In the graph shown at the bottom, a solid line represents an example of the waveform of the voltage output by the capacitance measuring unit 16 when the probe 4 descends at a constant speed. Figure 2 In the lower part, the intermediate value between the output voltage when the tip of probe 4 is away from the liquid surface and the output voltage when the tip of probe 4 is in contact with the liquid surface is set as the threshold. When the voltage output by the capacitance measuring unit 16 reaches the threshold value of the threshold storage unit 18 at time T0, the determination unit 17 determines that the tip of probe 4 is in contact with the liquid surface of liquid 2.

[0030] However, if the capacitance between the container 1 and the probe 4 increases excessively due to the formation of an electric double-layer capacitor, the output voltage of the capacitance measuring unit 16 decreases. Specifically, as... Figure 2 As shown by the dashed lines in the lower part of the graph, even if the tip of probe 4 contacts the surface of liquid 2, there is still a situation where the output voltage of the capacitance measuring unit 16 does not reach the threshold. If the processing voltage of the capacitance measuring unit 16 does not reach the threshold, the determination unit 17 will not determine that the tip of probe 4 is in contact with the surface of liquid 2, thus causing a false detection. Therefore, in Embodiment 1, the liquid surface detection device 13 is configured so that even if the capacitance between container 1 and probe 4 increases excessively, the voltage drop output by the capacitance measuring unit 16 can be suppressed.

[0031] use Figure 3 The structure of the liquid level detection device 13 in Embodiment 1 is described below. The liquid level detection device 13 of Embodiment 1 includes a capacitance measuring unit 16, a threshold storage unit 18, a determination unit 17, and a capacitor 20 disposed between the probe 4 and the capacitance measuring unit 16. Because the capacitor 20 is disposed between the probe 4 and the capacitance measuring unit 16, the capacitance between the input terminals of the capacitance measuring unit 16 decreases, thereby increasing the output voltage of the capacitance measuring unit 16. More specifically, when the capacitance between the container 1 and the probe 4 is Cp, and the capacitance of the capacitor 20 disposed between the probe 4 and the capacitance measuring unit 16 is Co, the capacitance Cx between the input terminals of the capacitance measuring unit 16 is as shown in the following formula.

[0032] Cx=Co·Cp / (Co+Cp)…(Formula 1)

[0033] The Cx obtained according to (Equation 1) is the product of Co / (Co+Cp) and Cp. Since Co / (Co+Cp) is less than 1, Cx is less than Cp. In other words, by setting the capacitor 20, the capacitance between the input terminals of the capacitance measuring unit 16 is reduced.

[0034] Figure 3The lower part of the graph shows the output voltage of the capacitance measuring unit 16. The waveform without capacitor 20 is represented by a dashed line, while the waveform with capacitor 20 is represented by a solid line. Additionally, Figure 3 In the chart, the waveform of the dashed line is... Figure 2 The waveform of the dashed line in the graph is the same, which indicates that the capacitance between container 1 and probe 4 has increased excessively. By setting capacitor 20, the output voltage of capacitance measuring unit 16 increases and exceeds the threshold. Therefore, determination unit 17 can determine that the tip of probe 4 is in contact with the liquid surface of liquid 2.

[0035] It should be noted that the capacitance Co of capacitor 20 is much smaller than the capacitance Cp between container 1 and probe 4, preferably a value below Cp / 1000. When Co is below Cp / 1000, the value of Cx is sufficiently reduced, and even if the capacitance between container 1 and probe 4 increases excessively, the decrease in voltage output by capacitance measuring unit 16 can be sufficiently suppressed. Furthermore, the structure of liquid level detection device 13 is not limited to... Figure 3 .

[0036] use Figure 4 Other structural examples of the liquid level detection device 13 in Embodiment 1 are described below. Figure 4 In the liquid level detection device 13 shown, compared to Figure 3 A diode 21 and a resistor 22 were added. Diode 21 and resistor 22 are connected in parallel between the transmission line 4b connected to the capacitor and ground. Furthermore, diode 21 is positioned with the direction from ground toward the transmission line 4b as the positive direction.

[0037] Even when probe 4 is separated from the liquid surface, charging capacitor 20 with external charge can lead to false detections of probe 4's tip being in contact with the liquid surface of liquid 2. Adding diode 21 and resistor 22 allows the external charge charged to capacitor 20 to be released to ground, preventing false detections of the liquid surface.

[0038] use Figure 5 Another structural example of the liquid level detection device of Example 1 is described. Figure 5 The liquid level detection device 13 shown has a capacitor 20 installed between the container 1 and the capacitance measuring unit 16. A diode 21 and a resistor 22 are connected in parallel between the transmission line 1a connected to the capacitor 20 and ground. It should be noted that the diode 21 is positioned with the direction from ground toward the transmission line 1a as the positive direction.

[0039] even though Figure 5In the liquid level detection device 13 shown, because a capacitor 20 is provided between the container 1 and the capacitance measuring unit 16, the output voltage of the capacitance measuring unit 16 increases and exceeds the threshold. As a result, the determination unit 17 can determine that the tip of the probe 4 is in contact with the liquid surface of the liquid 2.

[0040] Furthermore, because a diode 21 and a resistor 22 are connected in parallel between the transmission line 1a and ground, the external charge that has been charged into the capacitor 20 can be discharged to ground. Figure 4 Similarly, the liquid level detection device 13, Figure 5 The liquid level detection device 13 shown can also prevent false detection of the liquid level.

[0041] use Figure 6 Another example illustrating the overall structure of an automated analysis device. Figure 6 clock relative to Figure 1 The automatic analysis device in the middle is supplemented with a detection rod 30. The detection rod 30 is electrically connected to the liquid level detection device 13 via conveyor line 4a, switch 15, and conveyor line 4b, and functions as one electrode of the liquid level detection device 13. That is to say, Figure 6 In the automatic analysis device, based on the voltage output corresponding to the electrostatic capacitance between container 1 and detection rod 30, it is possible to detect whether the front end of detection rod 30 is in contact with the liquid surface of liquid 2.

[0042] Liquid level detection device 13 adopts Figures 3 to 5 Any structure in it. Figure 5 In the automatic analysis device shown, even if the capacitance between container 1 and detection rod 30 increases excessively, the voltage drop output by capacitance measuring unit 16 can be sufficiently suppressed. Figure 4 , Figure 5 In the case of the liquid level detection device 13, even when the detection rod 30 is separated from the liquid surface, the external charge can be discharged to ground even when the capacitor 20 is charged with an external charge. As a result, false detection of the liquid level can be prevented.

[0043] A detection rod 30 is positioned parallel to and next to probe 4, with its tip positioned closer to the liquid surface than the tip of probe 4. Because the tip of the detection rod 30 is closer to the liquid surface than the tip of probe 4, the descent of probe 4 can be stopped before the tip of probe 4 contacts the liquid surface, thus allowing for fine-tuning of the depth to which probe 4 is inserted into the liquid 2.

[0044] The embodiments of the present invention have been described above. The present invention is not limited to the above embodiments, and modifications can be made to the structural elements without departing from the spirit of the invention. Furthermore, multiple structural elements disclosed in the above embodiments can be appropriately combined. Further, some structural elements can be deleted from all the structural elements shown in the above embodiments.

[0045] Label Explanation

[0046] 1: Container; 1a: Transmission line; 2: Liquid; 3: Container drive unit; 4: Probe; 4a: Transmission line; 4b: Transmission line; 5: Probe drive unit; 6: Analysis unit; 7a: Flow path; 7b: Flow path; 8: Electrode; 8a: Transmission line; 10: Syringe; 11: Piston; 12: Control unit; 13: Liquid level detection device; 14: Power supply; 15: Switch; 16: Capacitance measuring unit; 17: Judgment unit; 18: Threshold storage unit; 20: Capacitor; 21: Diode; 22: Resistor; 30: Detection rod. Claims (as amended under Article 19 of the Treaty) 1. (Revised) An automated analysis device for analyzing a sample, characterized in that it comprises: A container used to hold liquids; The probe is used to attract the liquid; A capacitance measuring unit is used to output a voltage based on the capacitance between the container and the probe. A determination unit, which determines whether the tip of the probe is in contact with the liquid based on the voltage output by the capacitance measuring unit; and A capacitor, disposed between the probe or the container and the capacitance measuring unit, When the capacitance between the container and the probe is Cp, the capacitance of the capacitor is less than or equal to Cp / 1000. 2. (Delete). 3. The automatic analysis device according to claim 1, characterized in that, A diode and a resistor are connected in parallel between the transmission line connected to the capacitor and ground, with the diode having a positive direction from ground toward the transmission line. 4. (Modified) An automatic analysis device for analyzing samples, characterized in that it comprises: A container used to hold liquids; The probe is used to attract the liquid; A detection rod is disposed next to and parallel to the probe; A capacitance measuring unit is used to output voltage based on the capacitance between the container and the detection rod. A determination unit, which determines whether the tip of the detection rod is in contact with the liquid based on the voltage output by the capacitance measuring unit; and A capacitor, disposed between the detection rod or the container and the capacitance measuring unit, The tip of the detection rod is closer to the surface of the liquid than the tip of the probe. 5. (Delete).

Claims

1. An automated analysis device for analyzing samples, characterized in that, include: A container used to hold liquids; A probe used to attract the liquid; A capacitance measuring unit is used to output a voltage based on the capacitance between the container and the probe. The determination unit determines whether the tip of the probe is in contact with the liquid based on the voltage output by the capacitance measuring unit. as well as A capacitor is disposed between the probe or the container and the capacitance measuring unit.

2. The automatic analysis device according to claim 1, characterized in that, When the capacitance between the container and the probe is Cp, the capacitance of the capacitor is less than or equal to Cp / 1000.

3. The automatic analysis device according to claim 1, characterized in that, A diode and a resistor are connected in parallel between the transmission line connected to the capacitor and ground, with the diode having a positive direction from ground toward the transmission line.

4. An automatic analysis device for analyzing samples, characterized in that, include: A container used to hold liquids; A probe used to attract the liquid; A detection rod is disposed next to and parallel to the probe; A capacitance measuring unit is used to output voltage based on the capacitance between the container and the detection rod. The determination unit determines whether the tip of the detection rod is in contact with the liquid based on the voltage output by the capacitance measuring unit. as well as A capacitor is disposed between the detection rod or the container and the capacitance measuring unit.

5. The automatic analysis device according to claim 4, characterized in that, The tip of the detection rod is closer to the surface of the liquid than the tip of the probe.

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