Liquid surface detection device and liquid surface detection method

Abstract

The purpose of the present invention is to provide a liquid level detection device that determines the position of a liquid level with higher accuracy in consideration of a meniscus. To this end, this liquid level detection device is provided with: an irradiation unit that irradiates, from a side surface of a container in which a liquid is accommodated, light having wavelength components that differ in transmittance when passing through the liquid and when passing through air; a light receiving unit that receives transmitted light after the light irradiated from the irradiation unit has passed through the container; and an analysis unit that analyzes the transmitted light data at different positions in the vertical direction acquired by the light receiving unit, detects the position of the upper surface of the liquid in the container, and corrects the position of the upper surface on the basis of the amount of change in the amount of transmitted light between predetermined positions in the transmitted light data.

Description

Technical Field

[0001] The invention relates to a liquid level detection device and a liquid level detection method. Background Art

[0002] Automated analyzers are used to perform qualitative and quantitative analysis on samples such as blood and urine. Automated sample inspection systems are also used that automatically perform sample pretreatment steps such as centrifugation and transfer to various automated analyzers.

[0003] During the pretreatment process, the specimen may be centrifuged and the liquid level of the specimen after centrifugation may be measured. For example, if the specimen is blood, the blood is separated into serum (or plasma) and blood clots by centrifugation. After centrifugation, the liquid level detection device of the specimen inspection automation system measures the boundary surface and liquid volume of the layers within the specimen container.

[0004] Patent document 1 discloses the following liquid level detection device: an irradiation unit that irradiates light toward a portion of a specimen container containing a liquid substance is moved in a direction parallel to the axis of the specimen container, and the relative positions of the irradiation unit and the detection unit are controlled so that the detection unit moves to a position where it can detect transmitted light, and the transmitted light of the entire length of the specimen container is detected, thereby detecting the liquid level in the specimen container.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application No. 2005-516212 Summary of the Invention

[0008] Problems to be solved by the invention

[0009] However, the meniscus is not studied in Patent Document 1. Therefore, due to the meniscus, a position higher than the actual liquid surface is determined to be the liquid upper surface, which poses a problem in the accuracy of liquid surface detection.

[0010] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a liquid level detection device that can determine the liquid level position with higher accuracy by taking the meniscus into consideration.

[0011] Means for solving problems

[0012] In order to solve the above-mentioned problems, the liquid level detection device of the present invention comprises: an irradiation unit, which irradiates light of wavelength components with different transmittances when passing through the liquid and when passing through the air from the side of a container containing the liquid; a light receiving unit, which receives the transmitted light after the light irradiated from the irradiation unit passes through the container; and an analysis unit, which analyzes the transmitted light data at different positions in the upper and lower directions obtained by the light receiving unit, the analysis unit detects the upper surface position of the liquid in the container, and corrects the upper surface position based on the change in the amount of transmitted light between predetermined positions in the transmitted light data.

[0013] Effects of the Invention

[0014] The liquid level detection device of the present invention can determine the liquid level with higher accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is the overall structural diagram of the liquid level detection device.

[0016] Figure 2 This is a flowchart showing the flow of liquid level detection.

[0017] Figure 3 are examples of first transmitted light data and second transmitted light data.

[0018] Figure 4 It is an explanatory diagram of a specimen container having a meniscus formed thereon.

[0019] Figure 5 This is an example of measuring the change in the amount of transmitted light between points.

[0020] Figure 6 This is an example in which the variation in the amount of transmitted light between measurement points includes an offset value.

[0021] Figure 7 This is a flowchart showing the flow of determination of the serum upper surface.

[0022] Figure 8 This is a diagram showing the overall structure of a specimen inspection automation system equipped with a liquid level detection device. DETAILED DESCRIPTION

[0023] Figure 1 This is an overall structural diagram of the liquid level detection device 100 of this embodiment. The specimen to be detected by the liquid level detection device 100 is contained in a specimen container 120. The specimen container 120 is a substantially transparent cylindrical container that is elongated in the vertical direction and has a bottom, and is made of various resin materials, various glass materials, etc. It is a cylindrical or conical container. There are various types of specimen containers 120, and users use them according to their respective uses. There are also various shapes, and shapes with different diameters, shapes with different heights, shapes with different plugs, etc. are mixed. In Figure 1 2 shows an example in which a test tube is used as the sample container 120 .

[0024] The specimen contained in the specimen container 120 is separated by centrifugation into a layer of a substance having a relatively high specific gravity and a layer of a substance having a relatively low specific gravity. The specimen container 120 may also contain a separator 121 having a specific gravity intermediate between these substances. In this embodiment, a blood specimen collected from a patient is used as the specimen. The blood specimen is separated by centrifugation into a blood clot 122 having a relatively high specific gravity and serum 123 (or plasma) having a relatively low specific gravity. In addition, the separator 121 is contained in the specimen container 120, and after centrifugation, the blood clot 122 and the serum 123 are separated by the separator 121.

[0025] In addition to blood samples, the specimen may be a biological sample such as urine, a mixed solution of a biological sample and a reagent, or a reaction solution after the reaction of the biological sample and a reagent, etc. Separation may also be performed without using a separator.

[0026] The liquid level detection device 100 determines the boundary surface of the layer and the amount of liquid in the sample container 120. The liquid level detection device 100 mainly includes a first irradiation unit 101, a second irradiation unit 102, a first light receiving unit 103, a second light receiving unit 104, an analysis unit 105, a gripping unit 106, a driving unit 107, and a control unit 108.

[0027] The first irradiation unit 101 irradiates light of a first wavelength component (e.g., 1550±100 nm) from the side of the sample container 120. The light of the first wavelength component is absorbed by the liquid and does not pass through it. In other words, the light of the first wavelength component has different transmittance when passing through liquid and when passing through air.

[0028] The second irradiation unit 102 irradiates light having a second wavelength component (eg, 830±100 nm) different from the first wavelength component from the side surface of the sample container 120. The light having the second wavelength component transmits through the liquid.

[0029] The first light receiving unit 103 receives first transmitted light obtained by transmitting the light of the first wavelength component through the sample container 120 .

[0030] The second light receiving unit 104 receives second transmitted light obtained by transmitting the light of the second wavelength component through the sample container 120 .

[0031] The gripping portion 106 grips the sample container 120. The gripping portion 106 is moved in the vertical direction by the driving portion 107. The driving portion 107 moves the sample container 120 gripped by the gripping portion 106 in the vertical direction.

[0032] The analysis unit 105 analyzes the transmitted light data at different positions in the vertical direction. Specifically, the analysis unit 105 determines, for example, the boundaries between different liquids (layers), the boundary between the spacer and the liquid, and the boundary between the liquid and gas (air) based on the first transmitted light data obtained by the first light receiving unit 103 and the second transmitted light data obtained by the second light receiving unit 104. The method for determining the boundary will be described later.

[0033] Alternatively, a single light receiving unit and a single irradiating unit may be provided. However, by providing separate units for each wavelength, the first transmitted light data and the second transmitted light data can be acquired with a single vertical movement of the specimen container 120. In the case where a single light receiving unit and a single irradiating unit are provided, after acquiring the first transmitted light data, the wavelength of the irradiating unit is changed to the second wavelength to acquire the second transmitted light data, thereby enabling the acquisition of the first transmitted light data and the second transmitted light data.

[0034] The control unit 108 controls the operations of the first illuminating unit 101, the second illuminating unit 102, the first light receiving unit 103, the second light receiving unit 104, the analyzing unit 105, the gripping unit 106, and the driving unit 107. Furthermore, the control unit 108 may also have the functions of the analyzing unit 105. Furthermore, a control device provided external to the liquid level detecting device 100 may also have the functions of the analyzing unit 105 and the control unit 108.

[0035] Figure 2 1 is a flowchart showing the flow of liquid level detection in this embodiment. When the specimen container 120 reaches a predetermined liquid level detection position, the liquid level detection device 100 starts the detection operation, and the control unit 108 performs control as follows.

[0036] The control unit 108 grasps the arrived sample container 120 via the grasping unit 106 and lifts it via the driving unit 107 (step S201 ).

[0037] Then, the control unit 108 moves the specimen container 120 to the transmitted light measurement start position via the driving unit 107 (step S202). The transmitted light measurement start position may be at the upper side or the lower side of the specimen container 120.

[0038] Next, the control unit 108 moves the specimen container 120 vertically from the transmitted light measurement start position via the drive unit 107 while irradiating light via the first irradiation unit 101 and the second irradiation unit 102. At this time, the first light receiving unit 103 and the second light receiving unit 104 receive the transmitted light that has passed through the specimen container 120, and acquire transmitted light data at different positions in the vertical direction (step S203).

[0039] The transmittance of light varies depending on the type of liquid or spacer. Therefore, when the light is irradiated at the interface between different liquids, between a liquid and a spacer, or between a liquid and a gas, the amount of transmitted light received (transmitted light intensity) varies significantly. Therefore, locations where the amount of transmitted light changes significantly can be identified as interfaces. Specifically, the control unit 108 scans the sample container 120 vertically at predetermined positions (irradiation angles) along its circumference to acquire the amount of transmitted light, and the analysis unit 105 analyzes the changes. Alternatively, the transmitted light intensity data can be acquired as brightness data.

[0040] The specimen container 120 having completed the transmitted light measurement is returned to the position before being lifted by the driving unit 107, and the gripping unit 106 stops gripping the specimen container 120 (step S204). Thereafter, the specimen container 120 is conveyed to the next step.

[0041] Figure 3 The example of the first transmitted light data 301 and the second transmitted light data 302 acquired in step S203 is shown. The analyzing unit 105 detects the boundary surface based on the difference between the first transmitted light data 301 (transmitted light amount of the first transmitted light) and the second transmitted light data 302 (transmitted light amount of the second transmitted light).

[0042] Blood clot 122 barely transmits the light of the first wavelength component emitted by first illuminating unit 101 or the light of the second wavelength component emitted by second illuminating unit 102, thereby blocking them. Therefore, the amount of light transmitted by the first and second wavelength components when blood clot 122 is irradiated is approximately the same, resulting in low values. Spacer 121 transmits both the first and second wavelength components more readily than blood clot 122, resulting in a higher amount of transmitted light.

[0043] In contrast, the transmittance of serum 123 for the first wavelength component and the transmittance for the second wavelength component differ significantly. As described above, the first wavelength component is absorbed by the liquid and becomes impermeable, so the amount of light transmitted when irradiating serum 123 (first transmitted light data 301) is low. On the other hand, the second wavelength component, as described above, transmits light through the liquid, so the amount of light transmitted when irradiating serum 123 (second transmitted light data 302) remains relatively high.

[0044] The air above the serum 123 easily transmits both the first and second wavelength components. Therefore, when the air is irradiated with light, the amount of light transmitted is relatively high. Furthermore, the label 124 affixed to the specimen container 120, spanning the layers of the specimen, is less likely to transmit both the first and second wavelength components than air, resulting in a reduced amount of transmitted light. The amount of reduced transmitted light varies depending on the material of the label 124, the number of labels, and other factors.

[0045] As described above, the second transmitted light data 302 can also obtain a higher amount of transmitted light when irradiated to the insulator 121, the serum 123, and the air. On the other hand, the first transmitted light data 301 has a lower value when irradiated to the serum 123 than when irradiated to the insulator 121, and a higher value when irradiated to the air than when irradiated to the insulator 121. That is, the second transmitted light data 302 changes significantly at the boundary surface between the insulator 121 and the serum 123 and at the boundary surface between the serum 123 and the gas. In addition, regarding the amount of transmitted light when irradiated to the insulator 121 and the air, the first transmitted light data 301 is higher than the second transmitted light data 302, and regarding the amount of transmitted light when irradiated to the serum 123, the second transmitted light data 302 is higher than the first transmitted light data 301. Therefore, the analyzing unit 105 can convert Figure 3 The intersection of the first transmitted light data 301 and the second transmitted light data 302 in the image is detected as a boundary surface. Specifically, the position below the position where the difference between the first transmitted light data 301 and the second transmitted light data 302 is zero can be detected as the boundary surface between the spacer 121 and the serum 123, while the position above the position can be detected as the boundary surface between the serum 123 and the gas. Furthermore, the analysis unit 105 calculates the amount of serum in the specimen container 120 based on the detected boundary surface. The calculated serum amount is used in the plan for dispensing the serum.

[0046] However, the upper surface of the serum in the specimen container 120 is not actually horizontal. Figure 4 As shown, a meniscus is formed, and the liquid surface rises higher toward the container wall. Therefore, using only the above-described boundary surface determination method can lead to the problem of determining the upper surface of the meniscus, which is higher than the position to be detected, as the boundary surface between serum 123 and air. If the upper surface of the meniscus, which is higher than the upper surface of the serum, is determined as the boundary surface, the amount of serum 123 is overestimated.

[0047] If the serum volume is overestimated, insufficient serum 123 may be dispensed during dispensing, and the dispensing probe may reach the spacer 121 or blood clot 122 below the serum 123, potentially clogging the dispensing probe. If the dispensing probe becomes clogged, the specimen aspirated at the time of the clogging cannot be used, resulting in wasted specimens. Furthermore, the device stops, delaying test results. Furthermore, if a disposable needle is used for the dispensing probe, the used needle is also wasted.

[0048] Therefore, the analysis unit 105 of this embodiment not only detects the boundary surface between the serum 123 and the air, that is, the position of the upper surface of the serum 123, based on the transmitted light amounts included in the first transmitted light data 301 and the second transmitted light data 302, but also corrects the position of the upper surface of the serum 123 based on the amount of change in the transmitted light amount of the first transmitted light data 301 between predetermined positions. This correction allows for more accurate determination of the upper surface of the serum rather than the upper surface of the meniscus.

[0049] use Figure 5 A method for correcting the serum upper surface of the analysis unit 105 according to this embodiment will be described. Figure 5 This graph plots the variation in the amount of transmitted light between consecutive measurement points (positions) for the first transmitted light data 301 around the meniscus above the serum 123. As described above, the amount of light transmitted by the first wavelength component is low when irradiated by the serum 123 and high when irradiated by the air. Near the centers of the serum and air regions, the amount of transmitted light is stable, and the variation in the amount of transmitted light between measurement points is stable. On the other hand, near the boundary between the upper part of the serum region and the lower part of the air region, the amount of transmitted light fluctuates significantly, and the variation in the amount of transmitted light between measurement points increases.

[0050] Figure 5 The measurement point X in is the measurement point corresponding to the position of the upper surface of the serum detected based on the first transmitted light data 301 and the second transmitted light data 302. The measurement point X belongs to the part where the curved liquid surface is generated, so the change in the amount of transmitted light of the first transmitted light data 301 is large at the measurement point X and the measurement point X-1. The analysis unit 105 calculates the change in the amount of transmitted light between the nearest (adjacent) measurement points within a predetermined range from the measurement point X to the bottom (serum 123 side). Next, the analysis unit 105 confirms whether the calculated change is less than a threshold value. When there is a change that is less than the threshold value, the analysis unit 105 corrects the detected upper surface position so that it becomes a measurement point (position) with such a change. In Figure 5 The middle is the measurement point located at the top (air side) among the measurement points whose change amount is less than the threshold value. Therefore, the analysis unit 105 can correct the position of the serum upper surface from the position corresponding to the measurement point X to the position corresponding to the measurement point Y.

[0051] However, if Figure 6 As shown, the first wavelength component may sometimes cause deviations due to noise or labels passing through it. Therefore, it is preferable that the analysis unit 105 correct the measurement point only when there are consecutive positions where the change amount is less than the threshold. This can prevent erroneous corrections and more accurately determine the position of the serum upper surface.

[0052] In addition, the measurement point used to correct the upper surface of the serum can be any measurement point as long as the change is less than the threshold value. When using the measurement point on the upper side (air side), it is possible to determine a higher position as the liquid surface based on the correction of the meniscus, so that a larger amount of serum can be used for dispensing. On the other hand, when using the measurement point on the lower side (serum 123 side), it is possible to determine a lower position as the liquid surface based on the correction of the meniscus, so that the risk of clogging of the dispensing probe can be further reduced. Moreover, which measurement point to use can be predetermined for each device or can be appropriately set by the user.

[0053] Figure 7 This is a flowchart illustrating the process of determining the upper surface of serum by the analysis unit 105 according to this embodiment. The analysis unit 105 first detects the upper surface of serum based on the first transmitted light data 301 and the second transmitted light data 302 (step S701). Next, the analysis unit 105 analyzes the first transmitted light data 301 to correct the detected upper surface of serum.

[0054] Specifically, the analysis unit 105 calculates the amount of change between the measurement points of the first transmitted light data 301 (step S702). The analysis unit 105 then checks whether the amount of change between the measurement points from the detected upper surface of the serum to the measurement point using the serum side is less than a threshold value (step S703). It is preferable to check whether there is an amount of change less than the threshold value within a predetermined range from the upper surface of the serum to the serum side. By setting a predetermined range, even if the amount of transmitted light in the serum region is unstable due to noise, labels, etc., and the amount of change is not less than the threshold value, it is possible to prevent correction to a meniscus at a position significantly lower than the actual liquid level. The predetermined range is preferably a range corresponding to the height of the meniscus generated at the serum surface, for example, a range of 5 mm ± 2 mm from the detected upper surface of the serum to the serum side.

[0055] If there is a position within the predetermined range where the amount of change between measurement points is less than a threshold, the analysis unit 105 corrects the upper surface position from the detected serum upper surface to the measurement point used for calculating the amount of change (step S704). If there is no position within the predetermined range where the amount of change between measurement points is less than the threshold, the upper surface position is corrected to a position that is a predetermined value downward from the serum upper surface detected in step S701 (step S705). The predetermined value is preferably a value equivalent to the height of the meniscus, for example, 5 mm ± 2 mm. The predetermined range and the predetermined value may be the same value or different values.

[0056] According to this embodiment, the detected upper surface of the serum is corrected based on the first transmitted light data 301 obtained by irradiating the specimen container 120 with light of a first wavelength component that does not transmit liquid. This allows for more accurate determination of the upper surface of the serum, improving the accuracy of liquid level detection. Furthermore, by accurately knowing the specimen volume, it is possible to set more appropriate request items based on the specimen volume.

[0057] Furthermore, in the above-described embodiment, the position of the upper surface of the serum before correction is detected based on the first transmitted light data 301 and the second transmitted light data 302. However, detection may also be performed based on image analysis using a camera, or based on other methods. Furthermore, in the above-described embodiment, blood is used as an example of the target for liquid level detection. However, the present invention is also applicable to biological samples other than blood, such as urine, mixed solutions obtained by mixing biological samples with reagents, or reaction solutions obtained by reacting these.

[0058] The liquid level detection device can be used as a separate device, or as an automatic analyzer, a sample pre-processing device that automatically pre-processes the sample, or a part of a sample inspection automation system. Figure 8 An example will be described in which the above-mentioned liquid level detection device is installed as a part of a specimen inspection automation system.

[0059] Figure 8This diagram shows the overall structure of a sample inspection automation system. The sample inspection automation system includes: a pretreatment device 800 that performs various pretreatments on samples contained in sample containers 120; multiple analysis devices 801 that analyze the samples in the pretreated sample containers 120; a transport path 802 that transports racks 810 carrying sample containers 120 between the pretreatment device 800 and the analysis devices 801; multiple sample transfer units 803, each located between the transport path 802 and the multiple analysis devices 801, that transfer sample containers 120 between racks 810 transported by the transport path 802 and racks for loading and transferring sample containers 120 in each analysis device 801; and a control device 804 that controls the overall operation of the sample inspection automation system. The control device 804 also includes an operation control unit that controls operations and a storage unit that stores sample information such as analysis items and priority information of the samples contained in the sample containers 120 introduced into the sample testing automation system, and relationships between the samples and their identifiers.

[0060] The pre-processing device 800 is configured by connecting a plurality of units having various functions.

[0061] The pre-processing device 800 includes, for example, a specimen input unit 800a, a specimen storage unit 800b, a centrifugal separation unit 800c, a liquid amount determination unit 800d, a cap opening unit 800e, an aliquot container generation unit 800f, an aliquoting unit 800g, and a cap closing unit 800h.

[0062] The specimen loading unit 800a is used to load specimen containers 120 containing specimens into the specimen inspection automation system. Furthermore, the specimen loading unit 800a includes a specimen identification unit, a cap detection unit, and a specimen rack identification unit (not shown). These units identify the type of the specimen container 120 being transported, the shape of the cap, and the ID information assigned to the rack 810 holding the specimen container 120, thereby obtaining information identifying the transported specimen container 120. Furthermore, specimen rack identification units (not shown) are located at various locations within the specimen inspection automation system, enabling the location of the specimen container 120 to be confirmed.

[0063] The centrifugal separation unit 800 c is a unit for centrifugally separating the loaded sample container 120 .

[0064] The liquid amount determination processing unit 800d is a unit for measuring or determining the amount and color of the sample contained in the sample container 120 being transported using a laser light source unit and an image recognition unit (not shown).

[0065] The uncapping unit 800 e is a unit for uncapping a cap (not shown) from the inserted sample container 120 .

[0066] The aliquot-sample container generation processing unit 800f is a unit for preparing other sample containers 120 required for aliquoting the sample contained in the inserted sample container 120 by the subsequent aliquoting processing unit 800g and affixing barcodes and the like thereto.

[0067] The aliquoting unit 800g is a unit for subdividing the sample into other sample containers 120 prepared by the aliquot-sample container generating unit 800f so that the sample, which has not been centrifuged or has been centrifuged by the centrifugation unit 800c, can be analyzed by the analyzer 801 or the like.

[0068] The capping unit 800h is a unit for capping uncapped specimen containers 120 and subdivided specimen containers 120. Depending on the type of caps used to cap the specimen containers 120, the specimen inspection automation system may include two or more capping units 800h.

[0069] The specimen storage unit 800b is a unit for storing the specimen containers 120 capped by the capping processing unit 800h.

[0070] This configuration is merely an example, and other functional units may be provided in the pre-processing apparatus 800. The units of the pre-processing apparatus 800 are connected by a transport path 802, and the specimen container 120 mounted on the rack 810 is transported by the transport path 802.

[0071] The transport path 802 is a mechanism for transporting sample containers 120 introduced from the sample introduction unit 800a and the subdivided sample containers 120 dispensed in the dispensing processing unit 800g to various components within the sample inspection automation system, such as the centrifugal separation unit 800c, the dispensing processing unit 800g, and the analyzer 801. Furthermore, the transport path 802 is also used to transport sample containers to various mechanical components within each component, such as the centrifugal separation unit 800c, the dispensing processing unit 800g, and the analyzer 801, that perform predetermined operations.

[0072] The control device 804 controls the operation of each unit and mechanism within the automated specimen testing system and analyzes the measurement data in the analyzer 801. The control device 804 communicates with each unit and mechanism and can identify the location of the specimen within the automated specimen testing system based on the ID information of the rack 810.

[0073] The analyzer 801 is a unit for performing qualitative and quantitative analysis of the components of the transported specimen. As the analyzer 801, various automatic analyzers that analyze the components of pretreated specimens, such as biochemical analyzers, immunoassay analyzers, and coagulation analyzers, can be used depending on the application.

[0074] The liquid level detection device 100 of the above-described embodiment can be incorporated into, for example, the liquid amount determination processing unit 800d.

[0075] In addition, the present invention is not limited to the above-described embodiment, and includes various modifications.

[0076] For example, the detection object of the liquid level detection device is not limited to the specimen, but may be other liquids such as reagents. In addition, the above-mentioned embodiments are described in detail to explain the present invention in an easy-to-understand manner, and are not limited to necessarily having all the described structures.

[0077] Description of Reference Numerals

[0078] 100…Liquid level detection device, 101…First irradiation unit, 102…Second irradiation unit, 103…First light receiving unit, 104…Second light receiving unit, 105…Analysis unit, 106…Holding unit, 107…Drive unit, 108…Control unit, 120…Sample container, 121…Spacer, 122…Blood clot, 123…Serum, 124…Label, 301…First transmitted light data, 302…Second transmitted light data, 800…Pre-treatment Processing device, 800a…Specimen input unit, 800b…Specimen storage unit, 800c…Centrifugation separation unit, 800d…Liquid volume determination processing unit, 800e…Capping processing unit, 800f…Sub-specimen container generation processing unit, 800g…Dispensing processing unit, 800h…Capping processing unit, 801…Analyzing device, 802…Conveying path, 803…Specimen transfer unit, 804…Control device, 810…Stand.

Claims

1. A liquid level detection device, characterized in that: The liquid level detection device comprises: an irradiation unit for irradiating, from a side of a container containing a liquid, light having a wavelength component having different transmittances when passing through the liquid and when passing through air; a light receiving portion that receives transmitted light from the light irradiated from the irradiating portion after passing through the container; and an analyzing unit that analyzes the transmitted light data at different positions in the vertical direction obtained by the light receiving unit, The analyzing unit detects the upper surface position of the liquid in the container and corrects the upper surface position based on an amount of change in the amount of transmitted light between predetermined positions in the transmitted light data.

2. The liquid level detection device according to claim 1, characterized in that: The irradiation unit irradiates light having a first wavelength component having different transmittances when passing through the liquid and when passing through air, and light having a second wavelength component different from the first wavelength component. The light receiving unit receives first transmitted light of the first wavelength component transmitted through the container and second transmitted light of the second wavelength component transmitted through the container. The analyzing unit detects the upper surface position based on a difference between a transmitted light amount of the first transmitted light and a transmitted light amount of the second transmitted light.

3. The liquid level detection device according to claim 2, characterized in that: Regarding the amount of transmitted light relative to the liquid, the second transmitted light is higher than the first transmitted light, The amount of light transmitted through the air above the liquid is higher than that of the second light.

4. The liquid level detection device according to claim 3, characterized in that: The analyzing unit corrects the upper surface position to a position where the amount of change in the first transmitted light is smaller than a threshold value.

5. The liquid level detection device according to claim 4, characterized in that: The analyzing unit corrects the upper surface position only when positions where the amount of change is smaller than the threshold value continue.

6. The liquid level detection device according to claim 4, characterized in that: The analyzing unit determines whether the amount of change is smaller than the threshold value within a predetermined range downward from the detected upper surface position.

7. The liquid level detection device according to claim 6, characterized in that: When there is no position within the predetermined range where the amount of change is smaller than the threshold, the analyzing unit corrects the detected upper surface position to a position with a predetermined value downward.

8. The liquid level detection device according to claim 6, characterized in that: The predetermined range is a range corresponding to the height of the meniscus generated on the liquid surface of the liquid.

9. The liquid level detection device according to claim 7, characterized in that: The predetermined value is a value corresponding to the height of a meniscus generated on the liquid surface of the liquid.

10. A liquid level detection method, characterized in that: The liquid level detection method has the following features: a step of irradiating, from a side surface of a container containing a liquid, light with a wavelength component having different transmittances when passing through the liquid and when passing through air; A step of receiving, by a light receiving portion, light transmitted through the container after the light irradiated from the irradiating portion passes through the container; and The analyzing unit analyzes the transmitted light data at different positions in the vertical direction obtained by the light receiving unit, The analyzing unit detects the upper surface position of the liquid in the container and corrects the upper surface position based on an amount of change in the amount of transmitted light between predetermined positions in the transmitted light data.

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