Liquid acquisition and injection device

Abstract

The present invention provides a liquid collection and injection device for collecting liquid and injecting it into a specified location, comprising: a tubular suction head (153) for drawing and discharging liquid in a downward-facing state; a moving mechanism (160, 181, 182) for moving the suction head in three-dimensional space; a camera unit (155) for capturing images of the front end of the suction head; a photoelectric sensor (170) having a light-emitting unit (171) and a light-receiving unit (172); and a position determination unit (123) for determining the position of the front end of the suction head in the three-dimensional space based on the image of the front end of the suction head captured by the camera unit and the detection information obtained by detecting the front end of the suction head through the photoelectric sensor.

Description

Technical Field

[0001] This invention relates to a liquid collection and injection device. Background Technology

[0002] To quantify the metals and other elements contained in liquids such as drinking water, atomic absorption spectrophotometers are commonly used. Atomic absorption spectrophotometers work by thermally decomposing liquid samples to generate atomic vapor, and then irradiating this atomic vapor with light to obtain the absorption spectrum, thereby enabling qualitative and quantitative analysis of the sample.

[0003] An atomic absorption spectrophotometer comprises a measuring unit and an autosampler. The measuring unit includes: a sample heating section made of a graphite furnace; a light source for irradiating light onto atomic vapor generated in the sample heating section; and a detector for detecting the light passing through the atomic vapor. A sample injection port for injecting liquid samples is provided on the sample heating section. The autosampler includes: a sample placement section on which multiple sample containers for holding liquid samples are placed; a thin tubular pipette tip for aspirating and discharging liquid samples; an arm with the pipette tip mounted at its tip; and a moving mechanism for moving the arm vertically and horizontally. During analysis, the pipette tip mounted on the arm of the autosampler is inserted into the sample container to collect the liquid sample. Then, the moving arm inserts the tip of the pipette tip into the sample injection port, injecting the liquid sample into the sample heating section.

[0004] In such autosamplers, repeated use can lead to deterioration of the pipette tips, causing errors in sample injection volume, or blockage, resulting in contamination from previously measured liquid samples remaining inside. To prevent these issues, analysts need to replace the pipette tips at appropriate intervals. Furthermore, the sample heating element also deteriorates with repeated use, requiring replacement at suitable times. Since tip or heating element replacement is performed manually, installation errors can occur, such as the tip being installed at an angle or the heating element being misaligned. In atomic absorption spectrophotometers, for example, the sample inlet diameter is approximately 1.5 mm to 2.0 mm, and the pipette tip outer diameter is approximately 0.8 mm to 1.5 mm. Therefore, the permissible radial error (allowable error) is very small; if the installation error exceeds this allowable error, the pipette tip will contact the periphery of the sample inlet. Therefore, previously, after changing the pipette tip, a process called "teaching" was required, which involved adjusting the movement control of the adjustment arm so that the tip of the pipette tip was positioned directly above the center of the sample inlet. Patent Document 1 describes a method where images captured by a camera positioned to simultaneously capture the positions of both the tip and the sample inlet are displayed on a monitor, and the analyst reviews these images while performing the teaching process. Furthermore, Patent Document 2 describes a method where, during teaching, the position of the tip and the center of the sample inlet are determined by analyzing images captured by a camera positioned to simultaneously capture the positions of both the tip and the sample inlet.

[0005] Existing technical documents Patent documents Patent Document 1: International Publication No. 2021 / 124513 Patent Document 2: International Publication No. 2023 / 188553 Summary of the Invention The technical problem that the invention aims to solve However, based on images captured by a single camera, it is sometimes impossible to accurately determine the position of the suction head tip in the depth direction of the camera's field of view. High-precision position determination can be achieved by capturing images of the suction head tip with multiple cameras and determining the tip position based on the obtained images, but this increases manufacturing costs.

[0006] Furthermore, this type of problem is not limited to the autosampler of atomic absorption spectrophotometers; it is common in liquid collection and injection devices that use tubular pipette tips to collect liquids and inject them into designated locations.

[0007] The problem to be solved by the present invention is to achieve accurate determination of the tip position of the suction tip in a liquid collection and injection device that collects liquid through a thin tubular suction tip and injects it into a specified position at low cost.

[0008] Solution to the above technical problems The liquid collection and injection device of the present invention was developed to solve the above-mentioned problems. It is a liquid collection and injection device that collects liquid and injects it into a designated location, and has the following features: A tubular suction tip that draws in and discharges liquid with its tip pointing downwards; A moving mechanism that allows the suction head to move in three-dimensional space; A camera unit that captures images of the front end of the suction head; A photoelectric sensor having a light-emitting part and a light-receiving part; and The position determination unit determines the position of the tip of the suction head in the three-dimensional space based on an image of the tip of the suction head captured by the camera unit and detection information obtained by detecting the tip of the suction head through the photoelectric sensor.

[0009] Invention Effects According to the liquid collection and injection device of the present invention having the above-described configuration, accurate determination of the tip position of the suction nozzle can be achieved at low cost. Attached Figure Description

[0010] [ Figure 1 [Illustration] is a schematic diagram of the atomic absorption spectrophotometer according to Embodiment 1 of the present invention.

[0011] [ Figure 2 [Image 1] is a side view of the suction head moving mechanism in this embodiment.

[0012] [ Figure 3 [This is a perspective view showing the front end of the arm and the photoelectric sensor in this embodiment.]

[0013] [ Figure 4 [Illustration 1] is a schematic diagram showing the light-receiving part of the photoelectric sensor in this embodiment.

[0014] [ Figure 5 [This is a flowchart illustrating the steps involved in determining the center position of the sample injection port and the tip position of the suction tip in this embodiment.]

[0015] [ Figure 6 [This is a schematic diagram showing another configuration example of the analysis unit in this embodiment.]

[0016] [ Figure 7 [Illustration] is a schematic diagram of the atomic absorption spectrophotometer according to Embodiment 2 of the present invention.

[0017] [ Figure 8 [Image 1] is a side view of the suction head moving mechanism in this embodiment.

[0018] [ Figure 9 [This is a flowchart illustrating the steps involved in determining the center position of the sample injection port and the tip position of the suction tip in this embodiment.]

[0019] [ Figure 10 [This is a side view showing another example of the suction head moving mechanism in this embodiment.]

[0020] [ Figure 11 The graph shows the relationship between working distance and arm height during inspection.

[0021] [ Figure 12 [Image showing the result of aligning the tip of the pipette with the sample injection port based solely on images captured by a camera.]

[0022] [ Figure 13 [Image showing the result of aligning the tip of the pipette with the sample injection port based on images captured by a camera and detection results from a photoelectric sensor.] Detailed Implementation

[0023] Hereinafter, the configuration for implementing the present invention will be described with reference to the accompanying drawings. Furthermore, in the drawings described below, the drawing scale may differ from the actual scale, or some constituent elements may be omitted for ease of understanding of the main components.

[0024] [Implementation Method 1] Figure 1 This is a schematic diagram of the atomic absorption spectrophotometer according to Embodiment 1 of the present invention. This atomic absorption spectrophotometer is a flameless (electrically heated) atomic absorption spectrophotometer that atomizes samples without using a flame. It includes: an analysis unit 110 having a measurement unit 140 and an autosampler 150; and a control / processing unit 120 that controls the operation of the analysis unit 110 and processes the data acquired by the analysis unit 110. Furthermore, Figure 1 In the middle, the analysis unit 110 is shown in a view from above.

[0025] The measuring unit 140 includes: a sample heating unit 141 (equivalent to a heating furnace in this invention); a light source 142 for irradiating light onto atomic vapor generated in the sample heating unit 141; and a detection unit 143 for spectral dispersion and detection of the light passing through the atomic vapor. The sample heating unit 141 is a cylindrical electric heating furnace with openings at both ends, and a sample injection port 144, a circular hole for injecting a sample, is provided on its circumferential surface near the center in its longitudinal direction. Furthermore, the sample heating unit 141 is mounted on the measuring unit 140 in such a state that its axis is approximately horizontal, with one end facing the light source 142, the other end facing the detection unit 143, and the sample injection port 144 facing upwards. In this embodiment, the sample heating unit 141 is, for example, 3 to 7 mm in diameter and 1.5 to 3 cm in length, but is not limited to these dimensions. The size of the sample injection port 144 is set to be small so that the atomic vapor generated within the sample heating unit 141 does not diffuse; its diameter is, for example, 1.5 mm to 2.0 mm. In the optical path from the light source 142 to the detection unit 143, the portion except for the area near the sample injection port 144 is covered by a light-shielding / heat-insulating component 145 for light shielding and heat insulation.

[0026] The autosampler 150 includes: a turntable 152 on which multiple sample containers 151 for holding liquid samples are placed; and a pipette tip moving mechanism 160 for moving pipette tips 153 for drawing and discharging liquid samples along a predetermined rotational track, or in the vertical direction. Figure 1 The following components are present: a photoelectric sensor 170; a stage 181 equipped with a turntable 152 and a suction head moving mechanism 160; and a mechanism for moving the stage 181 along two mutually orthogonal axes in the horizontal plane. Figure 1 The stage drive unit 182 moves along the X-axis and Y-axis directions. Furthermore, the suction head moving mechanism 160, the stage 181, and the stage drive unit 182 correspond to the moving mechanism in this invention.

[0027] like Figure 2 As shown, the suction head moving mechanism 160 includes: an arm 161 extending in the horizontal direction; a shaft member 162 extending downward from one end (base end) of the arm 161; and an arm drive unit 163, which rotates the arm 161 by rotating the shaft member 162 and moves the arm 161 in the vertical direction by moving the shaft member 162 up and down.

[0028] A pipette tip mounting portion 154 is provided on the lower surface near the tip of arm 161, and a thin tubular pipette tip 153 is mounted on the pipette tip mounting portion 154 with its tip pointing downwards. A liquid delivery tube (not shown) is connected to the base end of the pipette tip 153, and a suction / discharge mechanism (not shown), such as a syringe, is connected to the other end of the liquid delivery tube. The outer diameter of the tip portion of the pipette tip 153 is smaller than the diameter of the sample injection port 144, for example, approximately 0.8 mm to 1.5 mm. Furthermore, in... Figure 2In this process, the suction head 153 has a constant outer diameter along its entire length, but is not limited to this; for example, it can also be a tapered shape with the outer diameter gradually decreasing towards the front end.

[0029] like Figure 2 As shown, a camera 155 (corresponding to the camera unit in this invention) is mounted on the lower surface of arm 161, closer to the base end than the suction head mounting portion 154. The camera 155 only needs to be mounted such that it includes the front end of the suction head 153 in its field of view, except as described above. Figure 2 Besides being installed directly downwards as shown, it can also be installed at an angle so that the front end of the suction head 153 is near the center of the field of view. Furthermore, a light 156 is installed on the lower surface of the arm 161, further forward than the suction head mounting portion 154. The light 156 can be installed in any orientation that illuminates the front end of the suction head 153, except as shown below. Figure 2 In addition to being installed facing directly downwards, the nozzle 153 can also be installed at an angle with the front end positioned near the center of the area illuminated by the light 156. The light 156 can be made of LEDs, for example, but is not limited to this.

[0030] Arm 161 can be moved to the suction head moving mechanism 160 by means of the suction head moving mechanism 160. Figure 1 The solid line indicates the initial position, the dashed line indicates the sample collection position, and the dotted line indicates the imaging position. Furthermore, the arm 161, through the action of the suction head moving mechanism 160 and the stage drive unit 182, can be moved to... Figure 1 The detection position is indicated by a double-dotted line, and the sample injection position is indicated by a triple-dotted line. When arm 161 is in the sample collection position, the tip of the suction head 153 is inserted into the sample container 151 at a predetermined position on the turntable 152; when arm 161 is in the detection position, the tip of the suction head 153 is inserted between the light-emitting part 171 and the light-receiving part 172 of the photoelectric sensor 170. Furthermore, when arm 161 is in the sample injection position, the tip of the suction head 153 is inserted into the sample injection port 144. When collecting a sample from the sample container 151, the suction head moving mechanism 160 moves arm 161 to the sample collection position, and the suction and discharge mechanism draws the sample into the suction head 153. When injecting the drawn sample into the sample injection port 144, the suction head moving mechanism 160 and the stage drive unit 182 move arm 161 to the sample injection position, and the suction and discharge mechanism discharges the sample into the sample heating unit 141. In addition, the above-mentioned shooting position refers to the position where the camera 155 can capture an image that includes the front end of the suction head 153 but does not include the sample injection port 144.

[0031] Furthermore, the arm 161 can be moved to an offset position (not shown) by the action of the suction head moving mechanism 160 and the stage drive unit 182. This offset position is a position offset by a predetermined distance from the sample injection position in a predetermined direction. The offset position is the position where the camera 155 captures a picture of the sample injection port 144 without overlapping with the suction head 153. It can be the position after the arm 161 has moved upwards by a predetermined distance from the sample injection position, or the position after rotating by a predetermined angle from the sample injection position. Hereinafter, the above-mentioned sample collection position, shooting position, detection position, sample injection position, and offset position are sometimes collectively referred to as the target position.

[0032] like Figure 1 As shown, the photoelectric sensor 170 has a light-emitting part 171 and a light-receiving part 172, which are arranged at intervals and opposite to each other, and are so-called transmission-type (groove-type) photoelectric sensors. Figure 3 As shown, the light-emitting part 171 and the light-receiving part 172 are housed in a U-shaped housing 173 (but the light-receiving part 172 is not shown in this figure), configured such that light emitted from the light-emitting part 171 can illuminate the light-receiving part 172. The photoelectric sensor 170 is fixed at a predetermined height position within the autosampler 150 by a support member 174. Furthermore, in Figure 1 In this configuration, the photoelectric sensor 170 is positioned away from the stage 181, but it can also be positioned on the stage 181. The light-emitting portion 171 is, for example, composed of an LED element, and the light-receiving portion 172 is, for example, composed of a photodiode, but is not limited thereto. Figure 4 As shown, the light-receiving surface of the light-receiving portion 172 of the photoelectric sensor 170 is divided into two regions. Hereinafter, one region of the divided light-receiving surface will be referred to as the first region 175, and the other region as the second region 176. Furthermore, as... Figure 1 and Figure 4 As shown, the photoelectric sensor 170 is arranged such that the light-emitting part 171 and the light-receiving part 172 are located in substantially the same horizontal plane, and the first region 175 and the second region 176 of the light-receiving part 172 are arranged in the transverse (horizontal direction).

[0033] The control / processing unit 120 includes, as functional modules, a position information acquisition control unit 121, an image analysis unit 122, a position determination unit 123, a teaching information generation unit 124, an analysis control unit 125, and a measurement data processing unit 126. Furthermore, the control / processing unit 120 also includes a storage unit 127. The functions of the control / processing unit 120 are implemented by a computer equipped with a CPU, memory, and a large-capacity storage medium (such as a hard disk). This computer can be a dedicated computer for atomic absorption spectrophotometers, but typically a general-purpose computer such as a personal computer is used. A predetermined program is pre-installed in the computer, and the CPU executes this program, thus implementing the functions of each of the above-mentioned functional modules in software. Furthermore, the functions of the storage unit 127 are implemented by the large-capacity storage medium. The computer is connected to an input unit 128 for users (analysts) to input various instructions, and a display unit 129 for displaying various information. The display unit 129 may be composed of, for example, a liquid crystal display, and the input unit 128 may be composed of, for example, a keypad, a mouse, or a touchpad attached to the display unit 129.

[0034] The storage unit 127 stores various measurement conditions used when performing sample measurements using the atomic absorption spectrophotometer according to this embodiment (e.g., information relating the element to be measured to the type of light source used when measuring that element and the wavelength of light detected by the detection unit 143). Furthermore, the storage unit 127 stores information (driving information) required to move the arm 161 to the aforementioned target positions, including coordinates representing the initial position and each target position in the absolute coordinate system (world coordinate system) of the three-dimensional space of the analysis unit 110, or the driving amount of the arm drive unit 163 or the stage drive unit 182 required to move the arm 161 from the initial position to each target position (or from one target position to another).

[0035] The analysis control unit 125 responds to input operations from the analyst by reading measurement conditions stored in the storage unit 127 and controlling the operation of each part constituting the measurement unit 140 and the autosampler 150 to perform sample measurement. The measurement data processing unit 126 analyzes the measurement data obtained by the measurement unit 140 by appropriately processing the sample measurement data. Since the analysis control unit 125 and the measurement data processing unit 126 are the same as those found in conventional atomic absorption spectrophotometers, detailed descriptions are omitted.

[0036] As described above, in an atomic absorption spectrophotometer, with repeated use, the pipette tip 153 may deteriorate, leading to errors in sample injection volume, or become clogged, resulting in contamination from previously measured liquid samples remaining inside the tip. To prevent these situations, analysts need to replace the pipette tip 153 at appropriate intervals. Furthermore, since the sample heating element 141 also deteriorates with repeated use, analysts need to replace it at appropriate intervals. However, since the replacement of the pipette tip 153 or the sample heating element 141 is performed manually by the analyst, installation errors may occur, such as the pipette tip 153 being installed on the arm 161 at an angle, or the installation position of the sample heating element 141 being misaligned.

[0037] Therefore, in the atomic absorption spectrophotometer according to this embodiment, after replacing the pipette tip 153 and / or the sample heating unit 141, the analyst determines the tip position of the pipette tip 153 and the center position of the sample injection port 144 according to the following steps. Furthermore, the position information acquisition control unit 121 in the control / processing unit 120 controls the arm drive unit 163, the stage drive unit 182, the camera 155, and the illumination 156 in such a confirmation operation of the tip position of the pipette tip 153 and the center position of the sample injection port 144. The image analysis unit 122 performs predetermined processing on the image captured by the camera 155 and analyzes the processed image to determine the tip position of the pipette tip 153 and the center position of the sample injection port 144 in the image. Furthermore, the position determination unit 123 determines the actual tip position of the pipette tip 153 and the center position of the sample injection port 144 based on the analysis result of the image analysis unit 122 and the output from the photoelectric sensor 170. Furthermore, the teaching information generation unit 124 generates teaching information, which will be described later, based on the actual tip position of the suction head 153 and the center position of the sample injection port 144 determined by the position determination unit 123.

[0038] Figure 5 This is a flowchart illustrating the steps involved in determining the front end position of the pipette tip 153 and the center position of the sample injection port 144 in the atomic absorption spectrophotometer according to this embodiment.

[0039] First, when the analyst operates the input unit 128 to determine the position of the tip of the pipette 153 and the center position of the sample inlet 144, under the control of the position information acquisition control unit 121, the arm drive unit 163 moves the arm 161 from a predetermined position (e.g., the initial position described above) to the aforementioned shooting position (step 11). As described above, the shooting position is a position where the sample inlet 144 does not enter the field of view of the camera 155. Subsequently, while illuminating the area near the tip of the pipette 153 with the illumination 156, the position information acquisition control unit 121 causes the camera 155 to capture a picture of the tip of the pipette 153 (step 12), and saves the acquired image in the storage unit 127.

[0040] Subsequently, the position information acquisition and control unit 121 moves the arm 161 from the shooting position to the detection position via the arm drive unit 163 and the stage drive unit 182, thereby inserting the front end of the suction head 153 between the light-emitting part 171 and the light-receiving part 172 of the photoelectric sensor 170 (step 13). As a result, the light emitted by the light-emitting part 171 is blocked by the front end of the suction head 153 and then incident on the light-receiving part 172. The control / processing unit 120 acquires the output of the photoelectric sensor 170 at this time, that is, the output signal representing the difference or ratio of the amount of light received in the first region 175 and the amount of light received in the second region 176 of the light-receiving part 172, as the detection result obtained by the photoelectric sensor 170 (step 14), and stores it in the storage unit 127.

[0041] Next, under the control of the position information acquisition control unit 121, the arm drive unit 163 and the stage drive unit 182 move the arm 161 to the aforementioned offset position (step 15). As described above, the offset position is a position where the sample injection port 144 can be photographed without overlapping with the suction head 153. Subsequently, the position information acquisition control unit 121 illuminates the area around the sample injection port 144 by turning on the illumination 156, while simultaneously causing the camera 155 to photograph the sample injection port 144 (step 16), and saves the obtained image in the storage unit 127.

[0042] Subsequently, the image analysis unit 122 reads the data of each image obtained in steps 12 and 16 from the storage unit 127, and after performing noise reduction and other processing as needed, determines the front end position of the suction tip 153 in the image obtained in step 12 and the center position of the sample injection port 144 in the image obtained in step 16 (step 17). Specifically, for example, the contours of the suction tip 153 and the sample injection port 144 are extracted based on the brightness distribution in the image, and the front end position of the suction tip 153 and the center position of the sample injection port 144 are determined based on the extracted contour lines. At this time, for example, the center position of the ellipse defined by the contour line of the sample injection port 144 can be determined as the center position of the sample injection port 144. In addition, when determining the front end position of the suction tip 153, for example, a center line of the suction tip 153 can be drawn between two lines extending vertically in the contour line of the suction tip 153, and the intersection point of the portion of the contour line connecting the lower ends of the two lower lines (i.e., the contour line of the front end portion of the suction tip 153) and the center line can be determined as the front end position of the suction tip.

[0043] Subsequently, the position determination unit 123 determines the actual center position of the sample injection port 144 based on the center position of the sample injection port 144 in the image determined in step 17 (step 18). Furthermore, the correspondence between the center position of the sample injection port 144 in the image obtained at the offset position and the actual center position of the sample injection port 144 is pre-calculated and stored in the storage unit 127. Here, the actual center position of the sample injection port 144 can be represented, for example, as the coordinates of the center of the sample injection port 144 in the absolute coordinate system (world coordinate system) of the three-dimensional space of the analysis unit 110.

[0044] Subsequently, the position determination unit 123 determines the actual position of the tip of the suction head 153 based on the position of the suction head 153 in the image determined in step 17 and the detection result obtained by the photoelectric sensor 170 in step 14 (step 19). Here, the actual position of the tip of the suction head 153 can be expressed, for example, as the relative position of the tip of the suction head 153 with respect to the arm 161. This relative position can be expressed, for example, as the coordinates of the tip of the suction head 153 in a three-dimensional coordinate system (local coordinate system) with a reference point on the arm 161 (e.g., the center of the suction head mounting part 154) as the origin.

[0045] For example, if information regarding the correspondence between the tip position of the suction head 153 in the image captured at the shooting position and the actual tip position of the suction head 153 is stored in the storage unit 127 beforehand, the actual tip position of the suction head 153 can be inferred based on the tip position of the suction head 153 in the image determined in step 17 and the corresponding information. However, as described above, the tip position of the suction head 153 in the depth direction of the field of view cannot be accurately determined based on the image captured by the camera 155. For example, as... Figure 2In the example shown, if the tip of the suction head 153 is located at any one of point a, point b, or point c on axis A extending from the front end of the lens of the camera 155, the tip of the suction head 153 will be located at the same pixel in the image. Therefore, it is impossible to determine the location of the tip of the suction head 153 on axis A based solely on the image. Therefore, in the atomic absorption spectrophotometer according to this embodiment, in addition to the image captured by the camera 155, the position of the tip of the suction head 153 is determined based on the detection result obtained by the photoelectric sensor 170 in step 14. As described above, the detection result obtained by the photoelectric sensor 170 (i.e., the output signal of the photoelectric sensor obtained in step 14) reflects the difference or ratio between the incident light amount of the first region 175 and the incident light amount of the second region 176 of the light-receiving portion 172. For example, as... Figure 4 As shown, when viewed from the front, the center of the suction head 153 overlaps with the boundary lines of the first region 175 and the second region 176, the amount of light incident on the first region 175 is equal to the amount of light incident on the second region 176. On the other hand, if the center of the suction head 153 shifts from the boundary line towards the second region 176, the amount of light incident on the first region 175 increases relative to the amount of light incident on the second region 176; conversely, if the center of the suction head 153 shifts from the boundary line towards the first region 175, the amount of light incident on the first region 175 decreases relative to the amount of light incident on the second region 176. Therefore, by storing the difference or ratio of the received light amounts and the relationship between the boundary lines of the first region 175 and the second region 176 and the central axis of the suction head 153 in the horizontal direction (the arrangement direction of the first region 175 and the second region 176) in the storage unit 127 beforehand, the position of the suction head 153 in the horizontal direction can be determined based on the output signal of the photoelectric sensor 170 obtained in step 14. In the above Figure 2 In the example, if the position of the tip of the suction head 153 in the horizontal direction (left-right direction in the figure) can be determined, then the position of the tip of the suction head 153 on axis A can be determined. Thus, in the atomic absorption spectrophotometer according to this embodiment, when determining the position of the tip of the suction head 153, the position of the tip of the suction head 153 can be determined with high precision by utilizing the detection results of the photoelectric sensor 170 in addition to the image acquired by the camera 155. Furthermore, since the photoelectric sensor 170 is cheaper than the camera 155, according to this embodiment, manufacturing costs can be suppressed compared to the case where multiple cameras are installed in the analysis unit 110.

[0046] As described above, after the actual center position of the sample inlet 144 and the tip position of the pipette tip 153 are determined, the teaching information generation unit 124 generates driving information (teaching information) that takes into account installation errors by correcting the driving information stored in the storage unit 127 based on the actual center position of the sample inlet 144 and the actual tip position of the pipette tip 153 obtained in step 18 and step 19. Specifically, for example, based on the information of the actual positions of the center of the sample inlet 144 and the tip of the pipette tip 153 obtained above, and the information of the respective positions of the center of the sample inlet 144 and the tip of the pipette tip 153 under the assumption of no installation error (referred to as reference positions), the direction and magnitude of the offset between the reference positions and the actual positions are derived for the center position of the sample inlet 144 and the tip position of the pipette tip 153, respectively. In addition, the reference position information is obtained in advance and stored in the storage unit 127. Then, the teaching information generation unit 124 generates teaching information and stores it in the storage unit 127 by correcting the driving information stored in the storage unit 127 based on the information of the direction and magnitude of the offset (position offset information). Subsequently, in the sample measurement performed later, the analysis control unit 125 controls the arm drive unit 163 and the stage drive unit 182 based on the teaching information. As a result, when the sample collected by the pipette tip 153 is introduced into the sample heating unit 141, the tip of the pipette tip 153 can be accurately inserted into the center of the sample injection port 144.

[0047] Furthermore, in the above embodiment, the first region 175 and the second region 176 on the light-receiving surface of the photoelectric sensor 170 are arranged laterally (horizontally), but the arrangement direction of the first region 175 and the second region 176 is not limited to this. For example, the first region 175 and the second region 176 can also be arranged longitudinally (vertically). In this case, assuming that the front end of the suction head 153 has no positional displacement, the arm 161 is moved to a position where the front end of the suction head 153 is at the boundary between the first region 175 and the second region 176. Based on the ratio or difference between the light received by the first region 175 and the light received by the second region 176 at this time, the position of the front end of the suction head 153 in the vertical direction (i.e., the offset relative to the boundary) can be determined. Figure 2 In the example, even when the vertical position of the tip of the suction head 153 can be determined, the position of the tip of the suction head 153 on axis A can also be determined. Therefore, when using the photoelectric sensor 170 with this configuration, the position of the tip of the suction head 153 can be accurately determined. Furthermore, as the photoelectric sensor 170, a sensor whose light-receiving surface is divided in two directions (e.g., horizontal and vertical) can also be used. In this case, since information on the position of the tip of the suction head 153 in both directions can be obtained, the position of the tip of the suction head 153 can be determined more accurately.

[0048] Furthermore, in the above embodiment, a configuration is adopted in which the photoelectric sensor 170 is disposed within the autosampler 150, but as an alternative, such as Figure 6 As shown, the photoelectric sensor 270 can also be positioned above the sample injection port 244 of the measuring unit 240. Furthermore, in this figure, for... Figure 1 The configurations shown are identical or corresponding, and are marked with reference numerals that have the same last two digits. In this case, the photoelectric sensor 270 is arranged such that the first region 275 and the second region 276 of the light-receiving part 272 of the photoelectric sensor 270 are at the sample injection position ( Figure 6 The arms 261 are arranged along the extension direction of the first region 275 and the second region 276, with the boundary line of the first region 275 and the second region 276 aligned with the central axis of the sample inlet 244 when viewed from a direction perpendicular to the light-receiving surface. Then, after moving the arm 261 so that the tip of the suction head 253 is above the photoelectric sensor 270, the arm 261 is lowered so that the tip of the suction head 253 is positioned between the light-emitting part 271 and the light-receiving part 272 of the photoelectric sensor 270. Then, the position of the arm 261 is adjusted so that in the image captured by the camera 255 mounted on the arm 261, the tip of the suction head 253 is directly above the sample inlet 244, and the difference between the light received by the first region 275 and the second region 276 in the photoelectric sensor 270 becomes 0 (or the ratio of the light received by the first region 275 to the light received by the second region 276 becomes 1). Thus, the tip of the suction head 253 can be accurately positioned on the central axis of the sample inlet 244.

[0049] [Implementation Method 2] Next, refer to Figures 7-8 The configuration of the atomic absorption spectrophotometer according to Embodiment 2 of the present invention will be described. Furthermore, in Figure 7 and Figure 8 In China, for the sake of Figure 1 and Figure 2 The same or corresponding components shown are marked with the same reference numerals ending in the last two digits, and descriptions are omitted as appropriate. Furthermore, the atomic absorption spectrophotometer according to this embodiment is the same as the atomic absorption spectrophotometer according to Embodiment 1, except for the structure of the photoelectric sensor 370 and the method for determining the position of the tip of the pipette 353. Therefore, the following description mainly focuses on the differences from Embodiment 1, and other points are omitted as appropriate.

[0050] In the atomic absorption spectrophotometer described in this embodiment, such as Figure 8 As shown, the camera 355 is mounted on the arm 361 with its optical axis (the central axis of the camera 355 lens) X pointing directly downwards. Furthermore, although the basic configuration of the photoelectric sensor 370 in this embodiment is similar to... Figure 3The two methods are basically the same, but the light-receiving surface of the light-receiving part 372 is not divided. Instead, the detection method is based on the amount of light received by the light-receiving part 372 to detect whether there is an object in front of the light-receiving part 372 (i.e., between the light-projecting part 371 and the light-receiving part 372).

[0051] Regarding the steps for determining the front end position of the suction tip 353 and the center position of the sample injection port 344 in this embodiment, please refer to... Figure 9 The flowchart will be used for explanation. First, under the control of the position information acquisition control unit 321, the arm drive unit 363 moves the arm 361 to the same shooting position as in Embodiment 1 (i.e., Figure 7 (Step 21). Then, the position information acquisition control unit 321 illuminates the illumination 356 and simultaneously controls the camera 355 to capture an image including the front end of the suction head 353 (Step 22). Furthermore, this step is related to... Figure 5 Steps 11 and 12 in the flowchart are the same, so detailed explanations are omitted.

[0052] Subsequently, under the control of the position information acquisition control unit 321, the arm drive unit 363 and the platform drive unit 382 move the arm 361 to a predetermined position above the photoelectric sensor 370. Figure 7 and Figure 8 (Step 23). At this time, the front end of the suction head 353 is positioned higher than the photoelectric sensor 370 (the height of the front end of the camera lens 355 at this time is referred to as the "initial height P0"). Then, the arm drive unit 363 gradually lowers the arm 361, and stores the amount of descent L1 of the arm 361 until the front end of the suction head 353 is detected by the photoelectric sensor 370 in the storage unit 327 (Step 24).

[0053] Next, under the control of the position information acquisition control unit 321, the arm drive unit 363 and the platform drive unit 382 move the arm 361 to the same offset position as in Embodiment 1 (i.e., from...). Figure 7 The sample injection position, indicated by a three-dot line, is offset by a predetermined distance in a predetermined direction (step 25). Subsequently, the position information acquisition control unit 321 illuminates the illumination 356 and simultaneously controls the camera 355 to capture an image containing the sample injection port 344 (step 26). Furthermore, this step is related to... Figure 5 Steps 15 and 16 in the flowchart are the same, so detailed explanations are omitted.

[0054] Next, the image analysis unit 322 determines the tip position of the suction tip 353 in the image obtained in step 22 and the center position of the sample injection port 344 in the image obtained in step 26 (step 27). Then, the position determination unit 323 determines the actual center position of the sample injection port 344 based on the center position of the sample injection port 344 in the image determined by the image analysis unit 322 (step 28). Since steps 27 and 28 are related to... Figure 5 Steps 17 and 18 in the flowchart are the same, so detailed explanations are omitted.

[0055] Subsequently, the position determination unit 323 determines the actual position of the front end of the suction head 353 based on the position of the suction head 353 in the image determined in step 27 and the descent amount L1 of the arm 361 determined in step 24 (step 29). Specifically, a distance L0 from the initial height P0 to the upper limit of the height detectable by the photoelectric sensor 370 is predetermined and stored in the storage unit 327. By subtracting the descent amount L1 from this distance L0, the distance from the front end of the camera lens to the front end of the suction head 353 in the X direction of the optical axis of the camera 355 is determined. Hereinafter, this distance is referred to as the working distance (WD). Through the above steps, if the position of the front end of the suction head 353 in the image and WD are known, the actual position of the front end of the suction head 353 can be uniquely determined.

[0056] In addition, as an alternative to the distance L0, the following information can be pre-stored in the storage unit 327: the distance from the front end of the camera lens 355 to the front end of the reference suction head (hereinafter referred to as reference WD) when the predetermined suction head 353 (hereinafter referred to as reference suction head) is mounted on the arm 361 in a manner that does not produce the aforementioned positional offset; and the height of the arm 361 (hereinafter referred to as reference arm height) when the arm 361 with the reference suction head mounted is lowered from above the photoelectric sensor 370 and the front end of the reference suction head is detected by the photoelectric sensor 370. In this case, in step 24, instead of the descent amount, the height of the arm 361 when the front end of the suction head 353 (hereinafter referred to as the target suction head), which is the object of position determination, is detected by the photoelectric sensor 370 is determined; in step 29, the difference between the WD of the reference suction head and the target suction head is determined based on the difference between the reference arm height and the height of the arm 361 determined in step 24. Then, based on the difference in WD and the reference WD, the WD of the target suction head is determined. Furthermore, the relationship between the difference in WD and the height difference of arm 361 when the front end of suction head 353 is detected by photoelectric sensor 370 is predetermined and stored in storage unit 327.

[0057] Thus, according to the atomic absorption spectrophotometer of this embodiment, the actual position of the tip of the suction head 353 can be accurately determined by utilizing information obtained by detecting the tip of the suction head 353 by the photoelectric sensor 370 (i.e., the aforementioned drop amount L1) in addition to the image obtained by the camera 355.

[0058] Subsequently, the teaching information generation unit 324 generates teaching information based on the actual sample injection port 344 center position determined in step 28 and the actual suction tip 353 front end position determined in step 29, by correcting the driving information stored in the storage unit 327. Since this process is the same as described in Embodiment 1 above, a detailed description is omitted.

[0059] Furthermore, in the above-described embodiment 2, such as Figure 8 As shown, camera 355 is mounted on arm 361 with its optical axis X pointing directly downwards, but alternatively, as... Figure 10 As shown, the camera 455 can also be mounted on the arm 461 in an orientation where the optical axis X is tilted relative to the vertical direction. Furthermore, in this figure, for... Figure 8 The same or corresponding components shown are marked with the same reference numerals ending in the same two digits. When the camera 455 is tilted, the working distance of the suction head (object suction head 453), which serves as the object for position determination, can be calculated using trigonometric functions. Specifically, for example... Figure 10 As shown, let WD0 be the working distance of the suction head (reference suction head 457) mounted on arm 461 without the aforementioned positional offset, WD1 be the working distance of the object suction head 453 (the object for position determination), θ1 be the angle formed by the plane perpendicular to the optical axis X of camera 455 and the horizontal plane, θ2 be the angle formed by the axis A of the line connecting the front end of camera 455 lens and the front end of suction head 453 and the optical axis X, and L be the height difference of arm 461 (i.e., the difference in position between the reference suction head 457 and the front end of object suction head 453 in the height direction) when the front ends of reference suction head 457 and object suction head 453 are detected by photoelectric sensors (not shown). Then, the difference in working distance between reference suction head 457 and object suction head 453 (i.e., WD1-WD0) can be expressed as: L*(1 / SIN(90°-θ1-θ2))*COSθ2. Furthermore, the value of θ2 is determined based on the position of the front end of suction head 453 in the image determined in step 27 above. Therefore, by storing the values ​​of WD0 and θ1, as well as the height of arm 461 when the front end of the reference suction head 457 is detected by the photoelectric sensor, in the storage unit (not shown), and storing the correspondence between the position of the front end of the suction head 453 in the image and the value of θ2 in the storage unit, in step 29 above, WD1 (i.e., the working distance of the object suction head 453) can be calculated based on these values ​​and the height value of arm 461 when the front end of the object suction head 453 is detected by the photoelectric sensor in step 24.

[0060] Furthermore, in Embodiments 1 and 2 described above, the front end positions of the suction heads 153, 253, 353, and 453 are determined using images obtained at the shooting position, and the center positions of the sample inlets 144, 244, and 344 are determined based on images obtained at the offset position. However, alternatively, both the front end positions of the suction heads 153, 253, 353, and 453 and the center positions of the sample inlets 144, 244, and 344 can be determined based on images obtained at the offset position. Furthermore, in Embodiments 1 and 2, cameras 155, 255, 355, and 455 are mounted on the base end side of arms 161, 261, 361, and 461, and lighting 156, 256, 356, and 456 are mounted on the front end side of arms 161, 261, 361, and 461. However, conversely, cameras 155, 255, 355, and 455 can also be mounted on the front end side of arms 161, 261, 361, and 461, and lighting 156, 256, 356, and 456 can be mounted on the base end side of arms 161, 261, 361, and 461. Furthermore, in Embodiments 1 and 2, cameras 155, 255, 355, 455 and lighting 156, 256, 356, 456 are mounted on arms 161, 261, 361, 461. However, cameras 155, 255, 355, 455 or lighting 156, 256, 356, 456 or both can be mounted at other locations within the analysis units 110, 210, 310. Additionally, in the above embodiments, a configuration with only one camera 155, 255, 355, 455 is used. However, two or more cameras can be provided, with different cameras capturing images of the front ends of suction tips 153, 253, 353, 453 and sample injection ports 144, 244, 344, respectively.

[0061] Furthermore, in the above-described embodiments 1 and 2, the photoelectric sensors 170, 270, and 370 are transmissive sensors, and the light receiving parts 172, 272, and 372 detect a portion of the light emitted from the light projecting parts 171, 271, and 371 and blocked by the suction heads 153, 253, 353, and 453. However, they are not limited to this. The photoelectric sensors 170, 270, and 370 can also be reflective sensors, configured such that the light receiving part of the photoelectric sensor detects the light emitted from the light projecting part of the photoelectric sensor and reflected by the suction heads 153, 253, 353, and 453. Alternatively, a retro-reflective sensor with a light-emitting part, a reflective part, and a light-receiving part can be used as photoelectric sensors 170, 270, and 370. The light-receiving part detects light emitted from the light-emitting part of the photoelectric sensor, which is reflected by the reflective part and then partially blocked by the suction heads 153, 253, 353, and 453.

[0062] Furthermore, in Embodiments 1 and 2 described above, the present invention is applied to the autosampler of an atomic absorption spectrophotometer, but it is not limited thereto. The present invention can also be applied to autosamplers for other analytical devices (e.g., liquid chromatographs or gas chromatographs). In addition, the liquid collection and injection device involved in the present invention can also be a device for collecting liquids other than samples and supplying them to a designated location (e.g., a device for collecting culture medium containing cells and discharging it into a predetermined container, etc.).

[0063] [Example] Regarding the experiments conducted to confirm the effectiveness of the present invention, refer to... Figures 11-13 Please provide an explanation.

[0064] Figure 11 This is a graph showing the height of arm 361 (hereinafter referred to as "detection arm height") when the tip of suction head 353 is detected by photoelectric sensor 370 as arm 361 is lowered from a predetermined height above photoelectric sensor 370 in the atomic absorption spectrophotometer according to Embodiment 2. The vertical axis of the graph represents the distance from the front end of the camera lens 355 to the front end of suction head 353 (i.e., the working distance mentioned above), and the horizontal axis represents the detection arm height in the z-axis direction (vertical direction) when the predetermined height is set to 0. As can be seen from the graph, the detection arm height varies linearly with the working distance, and the reproducibility is also high. 2 =0.9979.

[0065] Figure 12 and Figure 13 These are images showing the results of aligning the tip of the pipette 353 with the sample injection port 344 in the atomic absorption spectrophotometer according to Embodiment 2. However, these images were taken using a plate having an opening ("injection hole" in the figure) of the same size as the sample injection port 344, instead of the sample heating unit 341. Figure 12 The results are shown after aligning the tip of the suction head 353 with the sample inlet 344 based solely on images captured by the camera 355. Figure 13 The results show the alignment of the tip of the suction head 353 with the sample inlet 344 based on images captured by camera 355 and a working distance determined by the method of embodiment 2. These figures clearly demonstrate that by using the working distance in addition to the image, a more accurate alignment can be achieved.

[0066] [plan] It will be apparent to those skilled in the art that the above exemplary embodiments are specific examples of the following schemes.

[0067] (Item 1) One aspect of the present invention relates to a liquid collection and injection device that collects liquid and injects it into a designated location, comprising: A tubular suction tip that draws in and discharges liquid with its tip pointing downwards; A moving mechanism that allows the suction head to move in three-dimensional space; A camera unit that captures images of the front end of the suction head; A photoelectric sensor having a light-emitting part and a light-receiving part; and The position determination unit determines the position of the tip of the suction head in the three-dimensional space based on an image of the tip of the suction head captured by the camera unit and detection information obtained by detecting the tip of the suction head through the photoelectric sensor.

[0068] (Item 2) The liquid collection and injection device involved in Item 2 is the same as the liquid collection and injection device involved in Item 1. The photoelectric sensor has multiple regions on the light-receiving surface of the light-receiving part arranged in a predetermined direction, and outputs a detection signal corresponding to the difference or ratio of the light received by each of the multiple regions. The position determination unit uses the detection signal of the photoelectric sensor when the front end of the suction head is located in the path of the light emitted from the light projection unit as the detection information.

[0069] (Item 3) The liquid collection and injection device involved in Item 3 is the same as the liquid collection and injection device involved in Item 1. The position determination unit uses the descent amount information of the suction head when it descends from above the photoelectric sensor to the position where the front end of the suction head is detected by the photoelectric sensor as the detection information.

[0070] (Item 4) The liquid collection and injection device involved in Item 4 is any one of the liquid collection and injection devices involved in Items 1 to 3. The liquid collection and injection device is an automatic sampler used to collect liquid samples from a sample container and inject them into the sample injection port provided in the sample heating section of an electrically heated atomic absorption spectrophotometer.

[0071] According to the liquid collection and injection apparatus described in items 1 to 4, in addition to the image captured by the camera unit, detection information obtained by detecting the tip of the suction head using a photoelectric sensor is also utilized, thereby enabling high-precision determination of the tip position of the suction head. Furthermore, since photoelectric sensors are relatively inexpensive, the liquid collection and injection apparatus described in items 1 to 4 can achieve high-precision determination of the tip position of the suction head without significantly increasing manufacturing costs.

[0072] Explanation of reference numerals in the attached figures 110...Analysis Department 120...Control / Processing Unit 121...Location Information Acquisition and Control Unit 122...Image Analysis Department 123...Location Determination Department 124... Teaching Information Generation Department 127... Storage Department 140... Measurement Department 141...Sample heating section 144... Sample injection port 150...Automatic Sampler 151... Sample container 152... turntable 153... suction head 155... camera 160... Suction head moving mechanism 161...arm 162...shaft member 163...arm drive unit 170... photoelectric sensor 171...Light projection department 172...Light-receiving section 175...First Area 176...Second Region 181...platform 182... Platform drive unit.

Claims

1. A liquid collection and injection device for collecting liquid and injecting it into a designated location, comprising: A tubular suction tip that draws in and discharges liquid with its tip pointing downwards; A moving mechanism that allows the suction head to move in three-dimensional space; A camera unit that captures images of the front end of the suction head; A photoelectric sensor, which has a light-emitting part and a light-receiving part; as well as The position determination unit determines the position of the tip of the suction head in the three-dimensional space based on an image of the tip of the suction head captured by the camera unit and detection information obtained by detecting the tip of the suction head through the photoelectric sensor.

2. The liquid collection and injection device as described in claim 1, wherein, The photoelectric sensor has multiple regions on the light-receiving surface of the light-receiving part arranged in a predetermined direction, and outputs a detection signal corresponding to the difference or ratio of the light received by each of the multiple regions. The position determination unit uses the detection signal of the photoelectric sensor when the front end of the suction head is located in the path of the light emitted from the light projection unit as the detection information.

3. The liquid collection and injection device as described in claim 1, wherein, The position determination unit uses the descent amount information of the suction head when it descends from above the photoelectric sensor to the position where the front end of the suction head is detected by the photoelectric sensor as the detection information.

4. The liquid collection and injection device as described in claim 1, wherein, The liquid collection and injection device is an automatic sampler used to collect liquid samples from a sample container and inject them into the sample injection port of the heating furnace of an electrically heated atomic absorption spectrophotometer.

Images