Liquid level sensor and gene sequencer

Abstract

The invention provides a liquid level sensor, which is used for measuring the liquid level of a reagent in a container, and comprises a capacitance plate which is used for being attached to the outer side wall of the container and is also used for forming a sensing capacitor with the ground; the capacitor plate comprises a binding face used for being attached to the container, the binding face comprises a first end and a second end which are oppositely arranged in the first direction, and the first end is used for being arranged towards the bottom of the container. The width of the binding surface in the direction perpendicular to the first direction is increased along with the approaching of the binding surface to the second end; the sensing circuit is electrically connected with the capacitor polar plate and is used for sensing the capacitance value of the sensing capacitor; wherein when the capacitor plate is attached to the container, the liquid level of the reagent in the container is perpendicular to the first direction. The invention further provides a gene sequencer comprising the liquid level sensor.

Description

TECHNICAL FIELD

[0001] The present application relates to a liquid level sensor and a gene sequencer using the same. BACKGROUND

[0002] A common non-contact liquid level sensor usually includes a capacitor plate for attaching to the outer side wall of a container, and a sensing capacitor is formed between the capacitor plate and the ground. The liquid level is calculated by sensing the change of the capacitance value of the sensing capacitor when the container is filled with reagent. However, the existing capacitor plate has a rectangular attachment surface for attaching to the outer side wall of the container. When the reagent filled in the container has high viscosity, it is not easy to detect the change of the liquid level caused by the reagent hanging on the groove wall of the container, so it is difficult to distinguish whether the result of the liquid level detection is affected by the reagent hanging. SUMMARY

[0003] The first aspect of the present application provides a liquid level sensor for measuring the liquid level of a reagent in a container, comprising:

[0004] a capacitor plate for attaching to the outer side wall of the container, the capacitor plate being configured to form a sensing capacitor with the ground; the capacitor plate comprises an attachment surface for attaching to the container, the attachment surface comprises a first end and a second end oppositely arranged in a first direction, the first end being configured to be arranged towards the bottom of the container; the width of the attachment surface perpendicular to the first direction increases as it approaches the second end; and

[0005] a sensing circuit electrically connected to the capacitor plate, configured to sense the capacitance value of the sensing capacitor;

[0006] When the capacitor plate is attached to the container, the liquid surface of the reagent in the container is perpendicular to the first direction.

[0007] The liquid level sensor provided by the embodiments of the present application has the attachment surface of the capacitor plate attached to the outer side wall of the container, and the width of the attachment surface perpendicular to the first direction increases as it approaches the second end. The liquid surface of the liquid in the container is perpendicular to the first direction. The higher the liquid surface, the greater the change rate of the area of the portion of the attachment surface corresponding to the reagent, thereby improving the sensitivity of the liquid level detection. When there is a slight change in the liquid surface, the change in the capacitance value of the sensing capacitor is obvious, thereby facilitating the confirmation of whether there is reagent hanging in the container, and being beneficial to eliminating the influence of the reagent hanging on the result of the liquid level detection and improving the measurement accuracy.

[0008] In an embodiment, the first end is arranged flush with the bottom of the container.

[0009] In one embodiment, the shape of the bonding surface is an isosceles triangle, and the vertex of the isosceles triangle is located at the first end.

[0010] In one embodiment, the shape of the mating surface is a right triangle, one right-angled side of the right triangle is parallel to the first direction, and the right angle of the right triangle is located at the second end.

[0011] In one embodiment, the shape of the bonding surface is semi-circular, and the diameter line of the semi-circle is disposed at the second end.

[0012] In one embodiment, the capacitance value of the sensing capacitor is calculated using the following formula:

[0013]

[0014] Wherein, C is the capacitance value of the sensing capacitor; ε is the dielectric constant of the sensing capacitor; S is the area of ​​the bonding surface; and d is the distance between the capacitor plate and the ground.

[0015] In one embodiment, the bonding surface includes a first portion corresponding to the reagent and a second portion not corresponding to the reagent, wherein a first sensing capacitance is formed between the first portion and the ground, and a second sensing capacitance is formed between the second portion and the ground.

[0016] In one embodiment, the sensing circuit includes a signal acquisition module and an inductor module. The inductor module is used to form an oscillation circuit with the sensing capacitor, and the signal acquisition module is used to sense the frequency change of the oscillation circuit to measure the capacitance value of the sensing capacitor.

[0017] In one embodiment, the capacitor plate is either a flexible copper-clad laminate or a printed circuit board.

[0018] A second aspect of this application provides a gene sequencer, comprising:

[0019] Sequencing slides;

[0020] A container for holding reagents and for containing the sequencing slide to immerse the sequencing slide in the reagents; and

[0021] The liquid level sensor described above is disposed on the outer wall of the container and is used to sense the liquid level of the reagent in the container. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the module structure of the liquid level sensor in the embodiments of this application.

[0023] Figure 2 This is a schematic diagram of the capacitor plate structure in Embodiment 1 of this application.

[0024] Figure 3 for Figure 2 A graph showing the relationship between the capacitance of the capacitor plates and the liquid level.

[0025] Figure 4 This is a schematic diagram showing the alignment of the capacitor plates and the container in a comparative example.

[0026] Figure 5 for Figure 4 A graph showing the relationship between the capacitance of the capacitor plates and the liquid level.

[0027] Figure 6 This is a schematic diagram showing the state of reagents adhering to a container.

[0028] Figure 7 This is a schematic diagram of the capacitor plate structure in Embodiment 2 of this application.

[0029] Figure 8 This is a schematic diagram of the capacitor plate structure in Embodiment 3 of this application.

[0030] Figure 9 This is a schematic diagram of the structure of the gene sequencer in the embodiments of this application.

[0031] Explanation of key component symbols: Liquid level sensor 100

[0032] Capacitor plates 10

[0033] bonding surfaces 11, 11'

[0034] First end 111, 111'

[0035] Second end 113, 113'

[0036] Part 1, page 112

[0037] Part Two, 114

[0038] Sensing circuit 30

[0039] Sensing capacitor C

[0040] Signal acquisition module 31

[0041] Inductor module 33

[0042] Heights h, h1, h2

[0043] Widths w, w1, w2

[0044] included angle α

[0045] Gene sequencer 200

[0046] Sequencing slide 210

[0047] Container 230

[0048] lateral wall 231

[0049] Reagent 240

[0050] Liquid level 241

[0051] Hanging material 243

[0052] Robotic Arm A

[0053] First direction X

[0054] The following detailed description, in conjunction with the accompanying drawings, will further illustrate this application. Detailed Implementation

[0055] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0056] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in this application's specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0057] To further illustrate the technical means and effects adopted by this application in achieving its intended purpose, the following detailed description of this application is provided in conjunction with the accompanying drawings and preferred embodiments.

[0058] Example 1

[0059] Please see Figure 1This application provides a liquid level sensor 100 for measuring the liquid level of reagent 240 in a container 230. The liquid level sensor 100 includes a capacitor plate 10 and a sensing circuit 30. The capacitor plate 10 is attached to the outer wall 231 of the container 230 and forms a sensing capacitor C with the ground. The sensing circuit 30 is electrically connected to the capacitor plate 10 and is used to sense the capacitance value of the sensing capacitor C. Specifically, the capacitor plate 10 and the ground are separated by the container 230 and air. When the container 230 is filled with reagent 240, the capacitance value of the sensing capacitor C formed between the capacitor plate 10 and the ground changes with the addition of reagent 240 because the dielectric constant of reagent 240 is different from that of air. Furthermore, the capacitance value of the sensing capacitor C will also differ depending on the proportion of reagent 240. That is, when the capacitor plate 10 is attached to the outer wall 231 of the container 230, the capacitance value of the sensing capacitor C will change as the liquid level of the reagent 240 in the container 230 changes. Therefore, by sensing the change in the capacitance value of the sensing capacitor C, the change in the liquid level of the reagent 240 in the container 230 can be deduced.

[0060] The capacitor plate 10 includes a contact surface 11 for contacting with the container 230, and the capacitance value of the sensing capacitor C is calculated using the following formula:

[0061]

[0062] Where C is the capacitance of sensing capacitor C, ε is the dielectric constant of sensing capacitor C, S is the area of ​​the bonding surface 11, and d is the distance between capacitor plate 10 and the ground. The bonding surface 11 and the distance between capacitor plate 10 and the ground are constants, while the dielectric constant varies with the liquid level of reagent 240 in container 230.

[0063] Specifically, please refer to Figure 2 The bonding surface 11 can be divided into a first part 112 corresponding to the reagent 240 and a second part 114 not corresponding to the reagent 240. A first sensing capacitor C1 is formed between the first part 112 and the ground, and a second sensing capacitor C2 is formed between the second part 114 and the ground. Obviously, the sensing capacitor C is the total capacitance value after the first sensing capacitor C1 and the second sensing capacitor C2 are connected in parallel. Therefore, the capacitance value formula of the sensing capacitor C can also be expressed as:

[0064]

[0065] Where ε1 is the dielectric constant of reagent 240, S1 is the area of ​​the first part 112, ε2 is the dielectric constant of air, and S2 is the area of ​​the second part 114. The dielectric constant of reagent 240 is typically greater than that of air. Therefore, as the liquid level 241 rises, the area of ​​the first part S1 increases, the area of ​​the second part S2 decreases, and the capacitance of the sensing capacitor C increases. In actual measurements, the capacitance of the second sensing capacitor C2 can be approximately ignored; that is, the capacitance of the sensing capacitor C is positively correlated with the area of ​​the first part 112.

[0066] The bonding surface 11 also includes a first end 111 and a second end 113 disposed opposite to each other in the first direction X. The first end 111 is positioned towards the bottom of the container 230, and the width w of the bonding surface 11 perpendicular to the first direction X increases as it approaches the second end 113. Specifically, the first direction X is the same as the direction of change of the liquid level of the reagent 240 in the container 230. That is, when the capacitor plate 10 is attached to the outer wall 231 of the container 230, the liquid level 241 of the reagent 240 in the container 230 is perpendicular to the first direction X. The width w of the bonding surface 11 gradually increases as it moves away from the first end 111. That is, as the liquid level height h of the reagent 240 in the container 230 increases, the width w of the bonding surface 11 corresponding to the liquid level 241 also increases.

[0067] The bonding surface 11 is an isosceles triangle, with its vertex at the first end 111 and its base at the second end 113. When the capacitor plate 10 is bonded to the container 230, the first part 112 corresponding to the bonding surface 11 and the reagent 240 in the container 230 is also an isosceles triangle. Let half of the vertex angle of the bonding surface 11 be the included angle α, then the area of ​​the first part 112 can be expressed as:

[0068] S1 = h 2 tanα (3)

[0069] Where h is the height of the liquid surface 241. Therefore, combining formulas (2) and (3), it can be seen that the capacitance value of the sensing capacitor C is approximately proportional to the square of the height h of the liquid surface 241. Please refer to... Figure 3 It can be seen that as the height h of the liquid level 241 increases, the rate of change of the capacitance value of the sensing capacitor C also increases.

[0070] In this embodiment, the apex angle of the mating surface 11 can be 60°, that is, the included angle α is 30°. In this case, the area of ​​the first part 112 and the height of the mating surface 112 can be expressed as:

[0071]

[0072] In this embodiment, the first end 111 is flush with the bottom of the container 230. Specifically, the first end 111 is flush with the bottom wall inside the container 230, so that the capacitor plate 10 can completely sense the liquid level of the reagent 240 in the container 230. In other embodiments, the first end 111 may also be located in other positions, such as above or below the bottom of the container 230, and this application does not impose any restrictions on this.

[0073] In this embodiment, the capacitor plate 10 is either a flexible copper-clad laminate or a printed circuit board. Specifically, when the capacitor plate 10 is a flexible copper-clad laminate, it can be electrically connected to the sensing circuit 30 via wires, and the capacitor plate 10 serves as a probe attached to the outer wall 231 of the container 230. When the capacitor plate 10 is a printed circuit board, the sensing circuit 30 can be directly integrated onto the capacitor plate 10. In other embodiments, the capacitor plate 10 can also be made of other conductive materials, and this application does not limit this. The capacitor plate 10 can be attached to the container 230 with adhesive or held against the outer wall 231 of the container 230 by other fixing devices, and this application does not limit this either.

[0074] Please continue reading. Figure 1 The sensing circuit 30 includes a signal acquisition module 31 and an inductor module 33. The inductor module 33 forms an oscillation circuit with the sensing capacitor C, and the signal acquisition module 31 senses the frequency change of the oscillation circuit to measure the capacitance value of the sensing capacitor C. Specifically, the inductor module 33 includes an inductor element, which is connected in series with the sensing capacitor C to form an LC oscillation circuit. When the signal acquisition module 31 sends a signal of a certain frequency to the LC oscillation circuit, the LC oscillation circuit will feed back different signals according to the different capacitance values ​​of the sensing capacitor C. The signal acquisition module 31 can calculate the capacitance value of the sensing capacitor C based on the feedback signal, thereby calculating the height h of the liquid level 241.

[0075] In this embodiment, the sensing circuit 30 is integrated on the TI-FDC2212 capacitive sensing chip. The capacitor plate 10 is connected to a capacitance transmission interface of a certain channel on the FDC2212 chip, while the other capacitance transmission interface on the TI-FDC2212 chip is left floating to achieve a grounding effect, thereby forming an oscillation circuit with the onboard inductor. In other embodiments, the sensing circuit 30 may also be integrated on other chips or circuits, and this application does not impose any restrictions on this.

[0076] The liquid level sensor 100 provided in Embodiment 1 of this application sets the contact surface 11 of the capacitor plate 10 into an isosceles triangle, with the vertex of the isosceles triangle set at the first end 111. This makes the capacitance value of the sensing capacitor C proportional to the square of the liquid level height h. The higher the liquid level, the greater the rate of change of the capacitance value of the sensing capacitor C, which is beneficial to improving the sensitivity of liquid level detection, thereby avoiding the influence of material buildup on liquid level detection and improving detection accuracy.

[0077] Specifically, please refer to the following: Figure 4 and Figure 5 In a pair of proportions, the contact surface 11' of the capacitor plate 10 is rectangular, meaning the width w of the contact surface 11' from the first end 111' to the second end 113' is a constant. At this time, the relationship between the height h of the liquid surface 241 and the capacitance value of the sensing capacitor C is:

[0078]

[0079] That is, the capacitance value of the sensing capacitor C is directly proportional to the height h of the liquid surface 241.

[0080] Please see Figure 6 When the reagent 240 in container 230 is a highly viscous liquid, it will adhere to the inner wall of container 230, forming a deposit 243. During the liquid level detection process, the deposit 243 will gradually flow downwards over time, eventually restoring the liquid surface 241 to a flat state. During this process, the height h of the liquid surface 241 will change with the change in the deposit 243. However, because the change in the height h of the liquid surface 241 is relatively small, the capacitance value of the sensing capacitor C formed by the capacitor plate 10 provided in the comparative example also changes relatively little, making it impossible to accurately determine whether the measured liquid level height h is affected by the deposit.

[0081] In this embodiment, by setting the capacitance value of the sensing capacitor C to be proportional to the square of the height h of the liquid level 241, a small change in the height h of the liquid level 241 can be fed back as a larger change in capacitance value, thereby improving the sensitivity of liquid level detection. This helps determine whether there is material adhering to the container 230 and facilitates obtaining an accurate height h of the liquid level 241.

[0082] Example 2

[0083] Please see Figure 7The liquid level sensor 100 provided in this embodiment is used to measure the liquid level of reagent 240 in container 230. The liquid level sensor 100 includes a capacitor plate 10 and a sensing circuit 30. The capacitor plate 10 is attached to the outer wall 231 of container 230 and forms a sensing capacitor C with the ground. The sensing circuit 30 is electrically connected to the capacitor plate 10 and is used to sense the capacitance value of sensing capacitor C. The difference from Embodiment 1 is that the capacitor plate 10 provided in this Embodiment 2 has a semi-circular contact surface 11. The diameter line of the semi-circular contact surface 11 is set at the second end 113, and the midpoint of the arc of the semi-circular contact surface 11 is set at the first end 111. This makes the width w1 on the contact surface 11 corresponding to the liquid level 241 less than w2 when the height h1 of the liquid level 241 is less than the height h2.

[0084] Specifically, the bonding surface 11 can be set to other shapes, and the rate of change of the capacitance value of the sensing capacitor C increases with the increase of the height h of the liquid surface 241. This improves the sensitivity of detecting the height h of the liquid surface 241.

[0085] Example 3

[0086] Please see Figure 8 The liquid level sensor 100 provided in this embodiment is used to measure the liquid level of reagent 240 in container 230. The liquid level sensor 100 includes a capacitor plate 10 and a sensing circuit 30. The capacitor plate 10 is attached to the outer wall 231 of container 230 and forms a sensing capacitor C with the ground. The sensing circuit 30 is electrically connected to the capacitor plate 10 and is used to sense the capacitance value of sensing capacitor C. The difference from Embodiment 1 is that the capacitor plate 10 provided in this embodiment has a right-angled triangle shape for its contact surface 11. One right-angled side of the contact surface 11 of the right-angled triangle is parallel to the first direction X, and the right angle of the contact surface 11 of the right-angled triangle is set at the second end 113. This makes the width w1 on the contact surface 11 corresponding to the liquid level 241 less than w2 when the height h1 of the liquid level 241 is less than the height h2.

[0087] The liquid level sensor 100 provided in this application embodiment increases the width of the contact surface of the capacitor plate 10 as the liquid level rises. This results in a higher liquid level and a greater rate of change in the capacitance value of the sensing capacitor C, which helps to improve the sensitivity of liquid level detection, thereby avoiding the influence of material buildup on liquid level detection and improving detection accuracy.

[0088] Please see Figure 9This application also provides a gene sequencer 200, including a sequencing slide 210, a container 230, and a liquid level sensor 100 as described in any of the above embodiments. The sequencing slide 210 is used to carry the material to be sequenced, and the container 230 is used to hold reagents 240. The sequencing slide 210 is held by a robotic arm A and placed in the container 230, and is fully immersed in the reagents 240 to allow for biochemical reactions with the material in the sequencing slide 210. The liquid level sensor 100 is disposed on the outer wall 231 of the container 230 to sense the liquid level of the reagents 240 in the container 230.

[0089] The gene sequencer 200 provided in this application embodiment, by employing the liquid level sensor 100 in the above embodiment, can enhance the sensitivity of liquid level height h detection as the liquid level height h increases, thereby making a more obvious judgment when reagent 240 is attached, and thus eliminating the influence of attachment on the detection of liquid level height h. It has a simple structure and high reliability.

[0090] Those skilled in the art should recognize that the above embodiments are only used to illustrate this application and are not intended to limit this application. Any appropriate changes and variations made to the above embodiments within the essential spirit and scope of this application fall within the scope of protection claimed in this application.

Claims

1. A liquid level sensor for measuring a liquid level of a reagent in a container, characterized by, The liquid level sensor comprises: a capacitor plate attached to an outer sidewall of the container, the capacitor plate being configured to form a sensing capacitor with a ground surface; the capacitor plate comprises an attachment surface configured to attach to the container, the attachment surface comprising a first end and a second end oppositely arranged in a first direction, the first end being configured to be arranged towards a bottom of the container; a width of the attachment surface in a second direction perpendicular to the first direction increases as the second end is approached; and a sensing circuit electrically connected to the capacitor plate, the sensing circuit being configured to sense a capacitance value of the sensing capacitor; wherein, when the capacitor plate is attached to the container, a liquid surface of the reagent in the container is perpendicular to the first direction.

2. The liquid level sensor of claim 1, wherein The first end is arranged flush with the bottom of the container.

3. The liquid level sensor of claim 1, wherein, The attachment surface is shaped as an isosceles triangle, a vertex of the isosceles triangle being arranged at the first end.

4. The liquid level sensor of claim 1, wherein, The attachment surface is shaped as a right triangle, one leg of the right triangle being parallel to the first direction, a right angle of the right triangle being arranged at the second end.

5. The liquid level sensor of claim 1, wherein, The attachment surface is shaped as a semicircle, a diameter line of the semicircle being arranged at the second end.

6. The liquid level sensor of claim 1, wherein, The capacitance value of the sensing capacitor is calculated by the following formula: wherein, C is the capacitance value of the sensing capacitor; ε is a dielectric constant of the sensing capacitor; S is an area of the attachment surface; d is a distance between the capacitor plate and the ground surface.

7. The liquid level sensor of claim 1, wherein, The attachment surface comprises a first portion corresponding to the reagent and a second portion not corresponding to the reagent, the first portion and the ground surface form a first sensing capacitor, the second portion and the ground surface form a second sensing capacitor.

8. The liquid level sensor of claim 1, wherein, The sensing circuit comprises a signal acquisition module and an inductance module, the inductance module is configured to form an oscillation circuit with the sensing capacitor, the signal acquisition module is configured to sense a frequency change of the oscillation circuit to measure the capacitance value of the sensing capacitor.

9. The liquid level sensor of claim 1, wherein, The capacitor plate is one of a flexible copper clad plate and a printed circuit board.

10. A genetic sequencer, characterized by, The liquid level sensor comprises: a sequencing slide; a container configured to hold a reagent and to accommodate the sequencing slide so that the sequencing slide is soaked in the reagent; and the liquid level sensor according to any one of claims 1-9, the liquid level sensor being arranged on an outer sidewall of the container and configured to sense a liquid level of the reagent in the container. ​

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