CN215491759U - Parallel plate capacitance sensor with adjustable polar plate distance and polar plate area - Google Patents
Parallel plate capacitance sensor with adjustable polar plate distance and polar plate area Download PDFInfo
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- CN215491759U CN215491759U CN202121810097.4U CN202121810097U CN215491759U CN 215491759 U CN215491759 U CN 215491759U CN 202121810097 U CN202121810097 U CN 202121810097U CN 215491759 U CN215491759 U CN 215491759U
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Abstract
The utility model discloses a parallel plate capacitive sensor with adjustable polar plate distance and polar plate area, which comprises a connecting rod, a connecting rod fixing clamp, a three-dimensional moving platform, a supporting bottom plate, a horizontal object stage, a first polar plate and a second polar plate which are parallel to each other, wherein the first polar plate is fixed on the three-dimensional moving platform through the connecting rod and the connecting rod fixing clamp; the first electrode plate and the second electrode plate both use a glass plate as a substrate, a metal film electrode plate is manufactured on one side of the glass plate in a coating mode, and coating surfaces of the first electrode plate and the second electrode plate are oppositely arranged. The embodiment of the utility model can accurately adjust the polar plate distance and the polar plate area of the parallel plate capacitance sensor, has small edge effect of the polar plate, generates a capacitance value closer to a theoretical value, and can be widely applied to the capacitance sensor.
Description
Technical Field
The utility model relates to a capacitive sensor, in particular to a parallel plate capacitive sensor with adjustable polar plate distance and polar plate area.
Background
The capacitance sensor is a device for converting measured change into capacitance change, and has the characteristics of simple structure, small volume, good dynamic response, high sensitivity and the like, so that the capacitance sensor is widely applied to the detection fields of displacement, acceleration, vibration, pressure, differential pressure, liquid level, equal content and the like. The capacitance sensor has various structural types, wherein the parallel plate type capacitance sensor has simple structure, easy manufacture and simple capacitance calculation formula, can conveniently obtain the relative dielectric constant of a measured object, and is most widely applied to relevant detection of solid samples or liquid samples.
A parallel plate capacitor, generally composed of two or more electrode plates parallel to each other and a dielectric between the electrode plates, has a theoretical value C of capacitance between two parallel electrode plates according to a theoretical calculation formula: c ═ epsilon0ε S/d, wherein ε0The dielectric constant is vacuum dielectric constant, epsilon is the relative dielectric constant of the dielectric between the electrode plates, S is the opposite area of the two electrode plates, and d is the distance between the electrode plates. From the formula, divide by ε0Since changes in e, S, d can cause changes in the capacitance of the sensor, a parallel plate capacitive sensor is typically used with two of the three parameters e, S, d held constant and the other changed, when the capacitance of the sensor changesThe values are associated with the varying parameters.
When the parallel plate capacitance sensor is used for measuring the dielectric constant of a substance, the distance between the polar plates and the facing area of the polar plates are kept constant in the measuring process. The relative dielectric constants of different substances are greatly different, for example, at normal temperature, the relative dielectric constant of oil is 2-4, the relative dielectric constant of water is about 80, and the relative dielectric constants of the oil and the water are different in magnitude; on the other hand, the selection of the distance between the polar plates is limited by the viscosity of different substances to be detected and the difference of wettability between the polar plates; in addition, the specific detection mode (such as excitation voltage amplitude and excitation signal frequency) and the capacitance detection range of the sensor detection circuit also provide requirements for the precision of the plate area and the plate distance of the sensor. In order to make the capacitance value of the sensor fall within the detection range of the detection circuit and adapt to the characteristics of the detected object, different sensor plate sizes and plate distances are designed for different detected objects, and the application range of a parallel plate capacitance sensor with a certain fixed plate size and plate distance is limited.
Another problem with parallel plate capacitive sensors is the effect caused by the edge effect of the plates. The fringe effect of the capacitor refers to the effect caused by the difference of electric field distribution caused by the difference of electric charge distribution at the edge of the capacitor plate and on the outer surface of the capacitor plate and the electric charge distribution in the middle of the capacitor plate. Taking rectangular electrode plates as an example, each electrode plate of an ideal parallel plate capacitor is regarded as a geometric plane without thickness, and the capacitance theoretical value C between the parallel electrode plates is obtained; in fact, each polar plate is hexahedron, except for one right opposite surface, the other five surfaces have charge distribution, and when the thickness of the polar plate is not negligible relative to the right opposite surface area, the charge distribution is not negligible.
SUMMERY OF THE UTILITY MODEL
In view of this, an object of the embodiments of the present invention is to provide a parallel plate capacitive sensor with adjustable plate spacing and plate area, which can accurately adjust the plate spacing and the plate area of the parallel plate capacitive sensor, and has small edge effect of the plate, so as to generate a capacitance value closer to a theoretical value.
The embodiment of the utility model provides a parallel plate capacitive sensor with adjustable polar plate distance and polar plate area, which comprises a connecting rod, a connecting rod fixing clamp, a three-dimensional moving platform, a supporting bottom plate, a horizontal object stage, a first polar plate and a second polar plate which are parallel to each other, wherein the first polar plate is fixed on the three-dimensional moving platform through the connecting rod and the connecting rod fixing clamp; the first electrode plate and the second electrode plate both use a glass plate as a substrate, a metal thin film electrode plate is manufactured on one side of the glass plate in a coating mode, and coating surfaces of the first electrode plate and the second electrode plate are oppositely arranged.
Optionally, the metal film of the metal film electrode plate is provided with a tab and an electrode connecting wire, and the electrode connecting wire is connected with the tab and the detection circuit.
Optionally, the length and the width of the tab are equal, and the electrode connecting wire is a multi-core copper wire.
Optionally, the metal film of the metal film electrode plate is a gold film.
Optionally, the glass plate is a standard glass slide, and the planar shape of the metal thin film electrode plate is a rectangle.
Optionally, the connecting rod is made of an insulating rigid material, and the connecting rod is fixedly connected with the first electrode plate through glue.
Optionally, the metal thin film of the metal thin film electrode plate is a double-layer thin film, the surface thin film is a gold thin film, and the thin film between the surface thin film and the glass plate is a chromium thin film.
Optionally, the three-dimensional moving platform is a ball screw structure, and the adjustment mode of the ball screw structure includes electric adjustment and manual adjustment.
Optionally, the three-dimensional moving platform is a composite structure of a ball screw and a piezoelectric crystal, the moving direction of the ball screw includes X, Y and Z directions, and the moving direction of the piezoelectric crystal is a Z axis.
Optionally, the horizontal stage is mounted on the supporting bottom plate through three adjusting bolts, and the adjusting bolts are manually adjusted.
The implementation of the embodiment of the utility model has the following beneficial effects: in the embodiment of the utility model, the first electrode plate is fixed on the three-dimensional moving platform and can accurately move in multiple directions in a three-dimensional space, so that the distance between the electrode plates and the facing area of the parallel plate capacitor are accurately adjusted; the second electrode plate is fixed on a horizontal objective table, and the horizontal objective table can be horizontally adjusted within a certain range, so that the parallelism between the two electrode plates is adjusted; the first electrode plate and the second electrode plate both take glass plates as substrates, and metal film electrode plates are manufactured in a film coating mode, so that the thickness of the electrode plates is reduced, and the edge effect of the electrode plates is reduced; capacitance values closer to theoretical values can be produced by the parallel plate capacitance sensor described above.
Drawings
FIG. 1 is a schematic structural diagram of a parallel plate capacitive sensor with adjustable plate spacing and plate area according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram of an electrode plate of a parallel plate capacitive sensor according to an embodiment of the present invention.
Detailed Description
The utility model is described in further detail below with reference to the figures and the specific embodiments.
As shown in fig. 1, an embodiment of the present invention provides a parallel plate capacitive sensor with adjustable inter-electrode plate distance and inter-electrode plate area, including a supporting base plate 1, a three-dimensional moving platform 2, a connecting rod fixing clamp 3, a connecting rod 4, a horizontal stage 7, and a first electrode plate 5 and a second electrode plate 6 that are parallel to each other, where the first electrode plate 5 is fixed on the three-dimensional moving platform 2 through the connecting rod 4 and the connecting rod fixing clamp 3, the three-dimensional moving platform 2 is installed on the supporting base plate 1, the second electrode plate 6 is fixed on the horizontal stage 7, and the horizontal stage 7 is installed on the supporting base plate 1 through an adjusting bolt 8; the first electrode plate 5 and the second electrode plate 6 both use a glass plate as a substrate, a metal film electrode plate is manufactured on one side of the glass plate in a coating mode, and coating surfaces of the first electrode plate 5 and the second electrode plate 6 are oppositely arranged.
It will be appreciated by those skilled in the art that the glass plate has a high flatness and is not easily deformed, so that the metal film can maintain a planar form. Manufacturing metal thin-film electrode plates with various planar shapes, sizes and thicknesses by using a template mask in a film coating mode; the thickness of the film of the metal film electrode plate can be from tens of micrometers to several nanometers, the surface flatness of the film is extremely high, the sub-nanometer level can be achieved, the shape of the metal film electrode plate is close to an ideal plane, and the influence of the edge effect can be effectively reduced.
It should be noted that the relative position, the facing area, the distance between the electrode plates and the parallelism between the two electrode plates of the first electrode plate and the second electrode plate are precisely adjustable, so that the parallel plate capacitive sensor has a wide application range. The parallel plate capacitance sensor can be used for both solid samples and liquid samples: the electrode plate can be used for local detection of a large-size solid sample by adjusting the position of the electrode plate; the container is placed between the electrode plate and the horizontal object stage, so that the liquid sample detection device can be used for detecting the liquid sample; on the premise of not replacing the electrode plate, the positive area and the electrode plate distance of the electrode plate can be changed through the movement of the electrode plate, the capacitance of the parallel plate capacitance sensor is adjusted, and the detection range of various detection circuits is adapted.
Optionally, the metal film of the metal film electrode plate is provided with a tab and an electrode connecting wire, and the electrode connecting wire is connected with the tab and the detection circuit.
Specifically, as shown in fig. 2, a glass plate 9 is used as a substrate, a metal film 10 is plated on the glass plate 9 by a magnetron sputtering method, a tab 11 is disposed at an edge position of the metal film 10, an electrode connecting wire 12 is disposed on the tab 11, and the electrode connecting wire 12 is used for connecting the tab 11 and a detection circuit.
Optionally, the length and the width of the tab are equal, and the electrode connecting wire is a multi-core copper wire.
Optionally, the metal film of the metal film electrode plate is a gold film.
Optionally, the glass plate is a standard glass slide, and the planar shape of the metal thin film electrode plate is a rectangle.
Optionally, the connecting rod is made of an insulating rigid material, and the connecting rod is fixedly connected with the first electrode plate through glue.
Optionally, the metal thin film of the metal thin film electrode plate is a double-layer thin film, the surface thin film is a gold thin film, and the thin film between the surface thin film and the glass plate is a chromium thin film.
Optionally, the three-dimensional moving platform is a ball screw structure, and the adjustment mode of the ball screw structure includes electric adjustment and manual adjustment.
Optionally, the three-dimensional moving platform is a composite structure of a ball screw and a piezoelectric crystal, the moving direction of the ball screw includes X, Y and Z directions, and the moving direction of the piezoelectric crystal is a Z axis.
Optionally, the horizontal stage is mounted on the supporting bottom plate through three adjusting bolts, and the adjusting bolts are manually adjusted.
The implementation of the embodiment of the utility model has the following beneficial effects: in the embodiment of the utility model, the first electrode plate is fixed on the three-dimensional moving platform and can accurately move in multiple directions in a three-dimensional space, so that the distance between the electrode plates and the facing area of the parallel plate capacitor are accurately adjusted; the second electrode plate is fixed on a horizontal objective table, and the horizontal objective table can be horizontally adjusted within a certain range, so that the parallelism between the two electrode plates is adjusted; the first electrode plate and the second electrode plate both take glass plates as substrates, and metal film electrode plates are manufactured in a film coating mode, so that the thickness of the electrode plates is reduced, and the edge effect of the electrode plates is reduced; capacitance values closer to theoretical values can be produced by the parallel plate capacitance sensor described above.
The plate spacing and plate area adjustable parallel plate capacitive sensor of the present application is described below in two specific embodiments.
Example one
With reference to fig. 1 and fig. 2, an embodiment of the present invention provides a parallel plate capacitive sensor with adjustable inter-electrode plate distance and inter-electrode plate area, including a supporting base plate 1, a three-dimensional moving platform 2, a connecting rod fixing clamp 3, a connecting rod 4, a horizontal stage 7, and a first electrode plate 5 and a second electrode plate 6 that are parallel to each other, where the first electrode plate 5 is fixed on the three-dimensional moving platform 2 through the connecting rod 4 and the connecting rod fixing clamp 3, the three-dimensional moving platform 2 is installed on the supporting base plate 1, the second electrode plate 6 is fixed on the horizontal stage 7, and the horizontal stage 7 is installed on the supporting base plate 1 through an adjusting bolt 8; the first electrode plate 5 and the second electrode plate 6 both use a glass plate 9 as a substrate, metal film electrode plates are manufactured on one side of the glass plate 9 in a coating mode, and coating surfaces of the first electrode plate 5 and the second electrode plate 6 are oppositely arranged.
Wherein the glass plate is a standard glass slide, the length is 76mm, the width is 26mm, and the thickness is 1 mm; the metal film is prepared by a magnetron sputtering mode and is made of gold; the planar shape of the metal film is rectangular, the length is 50mm, the width is 20mm, and the thickness is 30 nm; the metal film is provided with a pole ear and an electrode connecting wire, the width of the pole ear is 5mm, the length of the pole ear is 5mm, and the electrode connecting wire is a multi-core copper wire and the diameter of the electrode connecting wire is 0.25 mm; the connecting rod is made of polyether ether ketone (PEEK), is of a cylindrical structure, has a diameter of 10mm, and is fixed with the first electrode plate through glue; the three-dimensional moving platform is of a ball screw structure and is driven by a stepping motor, the moving ranges in three directions are respectively 50mm by 50mm, and the displacement resolution is 20 nm; the horizontal objective table is supported by three precise adjusting bolts, the adjusting bolts are distributed in a three-point mode in an isosceles triangle mode, and a manual adjusting mode is adopted.
Example two
With reference to fig. 1 and fig. 2, an embodiment of the present invention provides a parallel plate capacitive sensor with adjustable inter-electrode plate distance and inter-electrode plate area, including a supporting base plate 1, a three-dimensional moving platform 2, a connecting rod fixing clamp 3, a connecting rod 4, a horizontal stage 7, and a first electrode plate 5 and a second electrode plate 6 that are parallel to each other, where the first electrode plate 5 is fixed on the three-dimensional moving platform 2 through the connecting rod 4 and the connecting rod fixing clamp 3, the three-dimensional moving platform 2 is installed on the supporting base plate 1, the second electrode plate 6 is fixed on the horizontal stage 7, and the horizontal stage 7 is installed on the supporting base plate 1 through an adjusting bolt 8; the first electrode plate 5 and the second electrode plate 6 both use a glass plate 9 as a substrate, metal film electrode plates are manufactured on one side of the glass plate 9 in a coating mode, and coating surfaces of the first electrode plate 5 and the second electrode plate 6 are oppositely arranged.
Wherein the glass plate is a standard glass slide, the length is 76mm, the width is 26mm, and the thickness is 1 mm; the metal film electrode plate and the comparison metal film electrode plate are prepared in a magnetron sputtering mode and have a double-layer film structure, wherein the bottom layer film is made of chromium, and the surface film is made of gold; the sensing metal thin-film electrode plate and the comparison metal thin-film electrode plate are rectangular in planar shape, 20mm in length, 20mm in width and 50nm in thickness; the sensing metal film electrode plate and the comparison metal film electrode plate are provided with a pole lug and an electrode connecting wire, the width of the pole lug is 3mm, the length of the pole lug is 3mm, and the electrode connecting wire is a multi-core copper wire and has the diameter of 0.25 mm; the pole plate connecting rod is made of polyether ether ketone (PEEK) and is of a cylindrical structure, the diameter of the pole plate connecting rod is 10mm, and the sensing metal thin film pole plate and the pole plate connecting rod are fixed through glue; the three-dimensional moving platform is of a composite structure of a ball screw and a piezoelectric crystal, the ball screw moving platform comprises X, Y, Z directions and is driven by a stepping motor, the moving ranges in the three directions are respectively 50mm by 50mm, and the displacement resolution is 20 nm; the piezoelectric crystal moving platform is a Z axis, the motion range is 100 mu m, and the displacement resolution is 2 nm; the horizontal objective table is supported by three precise adjusting bolts, the adjusting bolts are distributed in a three-point mode in an isosceles triangle mode, and a manual adjusting mode is adopted.
While the preferred embodiments of the present invention have been illustrated and described, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the utility model as defined by the appended claims.
Claims (10)
1. A parallel plate capacitive sensor with adjustable polar plate distance and polar plate area is characterized by comprising a connecting rod, a connecting rod fixing clamp, a three-dimensional moving platform, a supporting bottom plate, a horizontal object stage, a first polar plate and a second polar plate which are parallel to each other, wherein the first polar plate is fixed on the three-dimensional moving platform through the connecting rod and the connecting rod fixing clamp; the first electrode plate and the second electrode plate both use a glass plate as a substrate, a metal thin film electrode plate is manufactured on one side of the glass plate in a coating mode, and coating surfaces of the first electrode plate and the second electrode plate are oppositely arranged.
2. The adjustable plate spacing and plate area parallel plate capacitive sensor of claim 1 wherein said metallic thin film electrode plates have metal tabs and electrode connecting wires connecting said tabs and said sensing circuit.
3. The adjustable plate spacing and plate area parallel plate capacitive sensor of claim 2, wherein said tabs are of equal length and width and said electrode connecting wires are multicore copper wires.
4. The adjustable plate spacing and plate area parallel plate capacitive sensor of claim 1, wherein the metal thin film of the metal thin film electrode plate is a gold thin film.
5. The adjustable plate separation and plate area parallel plate capacitive sensor of claim 1 wherein the glass plate is a standard glass slide and the metal thin film planar shape of the metal thin film electrode plate is rectangular.
6. The adjustable plate spacing and plate area parallel plate capacitive sensor of claim 1, wherein the connecting rod is an insulating rigid material, and the connecting rod is fixedly connected to the first electrode plate by glue.
7. The adjustable plate separation and plate area parallel plate capacitive sensor of claim 1 wherein the metal thin film of the metal thin film plate electrode is a double layer thin film, the surface thin film is a gold thin film, and the thin film between the surface thin film and the glass plate is a chromium thin film.
8. The adjustable plate spacing and plate area parallel plate capacitive sensor of claim 1, wherein the three-dimensional moving platform is a ball screw structure, and the adjustment modes of the ball screw structure comprise electric adjustment and manual adjustment.
9. The adjustable plate spacing and plate area parallel plate capacitive sensor of claim 1, wherein the three-dimensional moving platform is a composite structure of a ball screw and a piezoelectric crystal, the moving direction of the ball screw comprises X, Y and Z directions, and the moving direction of the piezoelectric crystal is the Z axis.
10. The adjustable plate spacing and plate area parallel plate capacitive sensor of claim 1, wherein the horizontal stage is mounted on the support base plate by three adjustment bolts, the adjustment bolts being manually adjustable.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117870526A (en) * | 2024-03-11 | 2024-04-12 | 深圳市中图仪器股份有限公司 | Micro displacement sensor |
| CN117870526B (en) * | 2024-03-11 | 2024-05-31 | 深圳市中图仪器股份有限公司 | Micro displacement sensor |
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2021
- 2021-08-02 CN CN202121810097.4U patent/CN215491759U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117870526A (en) * | 2024-03-11 | 2024-04-12 | 深圳市中图仪器股份有限公司 | Micro displacement sensor |
| CN117870526B (en) * | 2024-03-11 | 2024-05-31 | 深圳市中图仪器股份有限公司 | Micro displacement sensor |
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