Capacitive displacement sensor electrode structure
By designing the dynamic gate plate transmitting electrode as an inverted trapezoidal structure and optimizing the electrode gap, the nonlinear error problem of traditional gate displacement sensors is solved, and higher measurement accuracy and stability are achieved, reducing manufacturing and development costs.
Patent Information
- Application Number
- CN202422443666.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-10
- Publication Date
- 2025-07-25
- Estimated Expiration
- 2034-10-10
AI Technical Summary
Due to the existence of the transmission electrode gap of the dynamic gate plate, the measurement accuracy is difficult to improve, and the nonlinear error has a great impact, affecting the stability of the measurement data.
The transmission electrode of the dynamic gate plate is designed as a plurality of trapezoidal structures that are inverted with each other, and coupling electrodes arranged at equal intervals are provided on the fixed gate plate to optimize the electrode gap width to meet the PCB processing capability and reduce nonlinear errors.
It improves measurement accuracy, enhances signal-to-noise ratio, makes measurement data more stable, and reduces the cost of sensor chip development.
Smart Images
Figure CN223154193U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of displacement sensors, in particular to an electrode structure of a capacitive grating displacement sensor. Background Art
[0002] A capacitive grating displacement sensor is a capacitive digital sensor based on the principle of variable area, which realizes large displacement by arranging a series of electrode patterns periodically on the displacement axis. It has been applied to measuring tools such as digital calipers for decades and is still widely used due to its unique advantages such as small size and low power consumption. The common structure of a capacitive grating linear displacement sensor includes a fixed grating plate and a moving grating plate that can slide linearly relative to the fixed grating plate. The fixed grating plate is composed of a series of electrodes arranged at equal intervals along the moving direction. The moving grating plate includes a set of transmitting electrodes and receiving electrodes. The transmitting electrodes are composed of a series of rectangular electrodes arranged at equal distances along the moving direction, and the series of electrodes are separated by insulating grooves with a certain width.
[0003] Since the series of rectangular transmitting electrodes on the moving grating plate are separated by insulating grooves with a certain width, affected by the manufacturing process, the width of the insulating grooves is mostly above 0.076 mm (PCB board mass production manufacturing process). When parallelly coupled with the corresponding coupling electrodes of the fixed grating plate, it will cause a large non-linear influence on the measurement accuracy, making it difficult to improve the measurement accuracy of the capacitive grating sensor. Adopting the method of smaller transmitting electrode gaps (below 0.076 mm), in addition to increasing the manufacturing difficulty and cost, it is also impossible to completely eliminate the non-linear influence. Summary of the Utility Model
[0004] The technical problem to be solved by the utility model is to provide an electrode structure of a capacitive grating displacement sensor, which overcomes the influence of the series of transmitting electrode gaps on the measurement accuracy, reduces or even eliminates the influence of the sudden non-linear error generated when the traditional series of transmitting electrode gaps face the edges of the fixed grating electrodes, improves the overall machine measurement accuracy, and can improve the signal-to-noise ratio of electrode coupling to make the measurement data more stable.
[0005] The technical solution for the utility model to solve the above technical problems is as follows: An electrode structure of a capacitive grating displacement sensor, comprising: a moving grating plate and a fixed grating plate, the moving grating plate is slidably installed on the fixed grating plate; a moving grating plate transmitting electrode is arranged on the moving grating plate, and the moving grating plate transmitting electrode is composed of a plurality of mutually inverted trapezoidal structures, and the plurality of trapezoidal structures in the moving grating plate transmitting electrode are arranged at equal intervals along the sliding direction of the moving grating plate.
[0006] The beneficial effects of the present utility model are as follows: The moving grid plate transmitting electrodes are arranged as a plurality of mutually inverted trapezoidal structures, which is conducive to reducing or even eliminating the influence of the abrupt non-linear error generated when the gap between the traditional series of transmitting electrode sheets faces the edge of the fixed grid electrode sheet during the sliding process of the moving grid plate along the fixed grid plate, improving the measurement accuracy of the whole machine, and the width of the electrode gap can be designed according to the processing capacity of ordinary PCB processing technology, which is conducive to processing and manufacturing.
[0007] On the basis of the above technical solution, the present utility model can be further improved as follows.
[0008] Further, a plurality of fixed grid plate coupling electrodes are arranged on the fixed grid plate, and the plurality of fixed grid plate coupling electrodes are arranged at equal intervals along the sliding direction of the moving grid plate.
[0009] The beneficial effect of adopting the above further scheme is that the fixed grid plate coupling electrodes are conducive to corresponding to the moving grid plate transmitting electrodes during the sliding process of the moving grid plate along the fixed grid plate, forming a change in capacitance according to the linear change of the relative area, and then measuring the displacement.
[0010] Further, the distance between two adjacent fixed grid plate coupling electrodes is the pitch length, the width of the fixed grid plate coupling electrode coupled with the moving grid plate transmitting electrode is less than or equal to 1 / 2 times of the pitch length, and the center distance between two trapezoidal structures in the plurality of trapezoidal structures of the moving grid plate transmitting electrode is 1 / 8 times of the pitch length.
[0011] The beneficial effect of adopting the above further scheme is that it is conducive to meeting the requirements of the signal processing of the existing sensor chip and reducing the development cost of the sensor chip.
[0012] Further, in the plurality of mutually inverted trapezoidal structures of the moving grid plate transmitting electrode, the length of the long bottom side of the trapezoid is greater than 1 / 8 times of the pitch length.
[0013] The beneficial effect of adopting the above further scheme is that it is conducive to increasing the displacement change amount per unit length, thereby improving the signal-to-noise ratio of the unit coupling electrode and making the measurement result more stable.
[0014] Further, in the plurality of mutually inverted trapezoidal structures of the moving grid plate transmitting electrode, the connection line from the edge of the short bottom side of a trapezoidal structure to the edge of the long bottom side of the adjacent inverted trapezoidal structure is parallel to the edge of the fixed grid plate coupling electrode.
[0015] The beneficial effect of adopting the above further scheme is that it is conducive to making the fixed grid plate coupling electrode and the moving grid plate transmitting electrode meet the requirements of the linear change of the measured electrical parameters of the variable area capacitance sensor during the displacement process, thus achieving the purpose of eliminating the abrupt non-linear error generated when the gap between the traditional series of transmitting electrode sheets faces the edge of the fixed grid electrode sheet.
[0016] Furthermore, a moving grating plate receiving electrode is also provided on the moving grating plate.
[0017] The beneficial effect of adopting the above further solution is that the moving grating plate receiving electrode is conducive to receiving the data after the capacitance of the moving grating plate transmitting electrode changes linearly, and transmitting the data to the sensor chip for processing. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 It is a schematic diagram of the electrode structure of a capacitance grating displacement sensor provided in Embodiment 1 of the present invention;
[0019] Figure 2 is Figure 1 an enlarged schematic diagram of area B in
[0020] Figure 3 It is a schematic diagram of the electrode structure of an absolute capacitance grating displacement sensor provided in Embodiment 2 of the present invention.
[0021] In the drawings, the list of components represented by each reference numeral is as follows:
[0022] 1. Moving grating plate; 2. Fixed grating plate; 11. Moving grating plate transmitting electrode; 12. Moving grating plate receiving electrode; 21. Fixed grating plate coupling electrode. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0023] The principles and features of the present invention are described below. The examples given are only used to explain the present invention and are not intended to limit the scope of the present invention.
[0024] As Figure 1 and Figure 2 shown, an electrode structure of a capacitance grating displacement sensor includes: a moving grating plate 1 and a fixed grating plate 2, and the moving grating plate 1 is slidably installed on the fixed grating plate 2; a moving grating plate transmitting electrode 11 is provided on the moving grating plate 1, and the moving grating plate transmitting electrode 11 is composed of a plurality of mutually inverted trapezoidal structures, and the plurality of trapezoidal structures in the moving grating plate transmitting electrode 11 are arranged at equal intervals along the sliding direction of the moving grating plate 1.
[0025] Among them, it should be noted that: in the technical solution of the present invention, for the sensor to measure displacement, it also needs to cooperate with a sensor chip. When the moving grating plate 1 slides along the fixed grating plate 2, the relative area between the moving grating plate transmitting electrode 11 and the fixed grating plate coupling electrode 21 on the fixed grating plate 2 continuously changes, and the change in area will cause a change in the capacitance between the electrodes. After the change in capacitance is processed by the sensor chip, it will be converted into a displacement amount. In this process, the transmission of data and the processing of data by the sensor chip both belong to the prior art;
[0026] Due to the existence of the isolation gap between the traditional moving grid plate transmitting electrodes, during the movement of the moving grid plate, the linear change of the coupling capacitance parameters cannot be guaranteed at the gap position. Although the edge effect can provide a certain compensation, there will still be non-linear changes in the measurement information, resulting in low overall accuracy of the capacitive grating sensor. In the technical solution of the present utility model, since the moving grid plate transmitting electrode 11 is of a trapezoidal structure and multiple trapezoidal structures in the moving grid plate transmitting electrode 11 are inverted relative to each other, when the moving grid plate 1 slides along the fixed grid plate 2, the relative area change between the moving grid plate transmitting electrode 11 and the fixed grid plate coupling electrode 21 on the fixed grid plate 2 is smoother compared with the prior art, and the resulting abrupt non-linear error is smaller, thereby improving the overall measurement accuracy of the whole machine.
[0027] The beneficial effect of the present utility model is that the moving grid plate transmitting electrode is set as multiple inverted trapezoidal structures, which is beneficial to reducing or even eliminating the influence of the abrupt non-linear error generated when the gap between the traditional series of transmitting electrode sheets faces the edge of the fixed grid electrode sheet during the sliding of the moving grid plate along the fixed grid plate, improving the overall measurement accuracy of the whole machine, and the electrode gap width can be designed according to the processing capacity of ordinary PCB processing technology, which is beneficial to processing and manufacturing.
[0028] Preferably, as Figure 1 and Figure 2 shown, a plurality of fixed grid plate coupling electrodes 21 are arranged on the fixed grid plate 2, and the plurality of fixed grid plate coupling electrodes 21 are arranged at equal intervals along the sliding direction of the moving grid plate 1.
[0029] The beneficial effect of adopting the above preferred scheme is that the fixed grid plate coupling electrode is beneficial to forming a capacitance change according to the linear change of the relative area corresponding to the moving grid plate transmitting electrode during the sliding of the moving grid plate along the fixed grid plate, and then measuring the displacement.
[0030] Preferably, as Figure 2 shown, the distance between two adjacent fixed grid plate coupling electrodes 21 is the pitch length a3, the width a5 of the fixed grid plate coupling electrode 21 coupled with the moving grid plate transmitting electrode 11 is less than or equal to 1 / 2 times of the pitch length, and the center distance a4 between two trapezoidal structures in the plurality of trapezoidal structures of the moving grid plate transmitting electrode 11 is 1 / 8 times of the pitch length a3.
[0031] The beneficial effect of adopting the above preferred scheme is that it is beneficial to meet the requirements of signal processing of existing sensor chips and reduce the development cost of sensor chips.
[0032] Preferably, as Figure 2As shown, among the multiple mutually inverted trapezoidal structures of the moving grating plate transmitting electrode 11, the length a2 of the long bottom side of the trapezoid is greater than one-eighth of the pitch length a3.
[0033] The beneficial effects of adopting the above preferred solution are as follows: It is beneficial to increase the displacement change amount per unit length, thereby improving the signal-to-noise ratio of the unit coupling electrode and making the measurement result more stable.
[0034] Preferably, as Figure 2 shown, among the multiple mutually inverted trapezoidal structures of the moving grating plate transmitting electrode 11, the connection line from the edge of the short bottom side of a trapezoidal structure to the edge of the long bottom side of the adjacent inverted trapezoidal structure is parallel to the edge of the fixed grating plate coupling electrode 21.
[0035] The beneficial effects of adopting the above preferred solution are as follows: It is beneficial to make the fixed grating plate coupling electrode and the moving grating plate transmitting electrode meet the requirements of the linear change of the measured electrical parameters of the variable area capacitance sensor during the displacement process, thus achieving the purpose of eliminating the sudden non-linear error generated when the gap between the traditional series of transmitting electrode sheets faces the edge of the fixed grid electrode sheet.
[0036] Preferably, as Figure 1 and Figure 2 shown, a moving grating plate receiving electrode 12 is further provided on the moving grating plate 1.
[0037] The beneficial effects of adopting the above preferred solution are as follows: The moving grating plate receiving electrode is beneficial to receiving the data after the capacitance of the moving grating plate transmitting electrode changes linearly and transmitting the data to the sensor chip for processing.
[0038] Among them, it should be noted that: as Figure 2 shown, in the preferred embodiment of the present invention, the length a1 of the short bottom side of the trapezoidal structure in the moving grating plate transmitting electrode 11 is equal to the distance b1 between two adjacent trapezoidal structures in the moving grating plate transmitting electrode 11; in the technical solution of the present invention, the smaller the difference between the trapezoidal short bottom side length a1 and the gap width b1, the more effective it is to eliminate the non-linear error caused by the gap. If the trapezoidal short bottom side is taken as an arc, or a1 is equal to zero (actually an isosceles triangle), it also has an improvement effect on improving the non-linear error caused by the electrode gap.
[0039] Preferably, as Figure 3 shown, the structure of the above-mentioned moving grating plate transmitting electrode 11 can be applied not only to the current incremental capacitive grating sensor but also to the differential absolute capacitive grating sensor, and its design method and principle are the same as those of the incremental capacitive grating sensor.
[0040] In the description of the present utility model, it should be understood that the orientation or positional relationship indicated by terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present utility model.
[0041] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present utility model, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.
[0042] In the present utility model, unless otherwise clearly specified and defined, terms such as "mounted", "connected", "connected to", "fixed" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements or the interaction relationship between two elements, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.
[0043] In the present utility model, unless otherwise clearly specified and defined, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "underneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.
[0044] In the description of this specification, the descriptions referring to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present utility model. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.
[0045] Although the embodiments of the present utility model have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present utility model. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present utility model.
Claims
1. An electrode structure of a capacitive grating displacement sensor, characterized in that, Comprising: A moving grating plate (1) and a fixed grating plate (2), wherein the moving grating plate (1) is slidably mounted on the fixed grating plate (2); A moving grating plate transmitting electrode (11) is provided on the moving grating plate (1), and the moving grating plate transmitting electrode (11) is composed of a plurality of mutually inverted trapezoidal structures, and the plurality of trapezoidal structures in the moving grating plate transmitting electrode (11) are arranged at equal intervals along the sliding direction of the moving grating plate (1).
2. The electrode structure of a capacitance grating displacement sensor according to claim 1, wherein A plurality of fixed grating plate coupling electrodes (21) are provided on the fixed grating plate (2), and the plurality of fixed grating plate coupling electrodes (21) are arranged at equal intervals along the sliding direction of the moving grating plate (1).
3. The electrode structure of a capacitance grating displacement sensor according to claim 2, wherein, The distance between two adjacent fixed grating plate coupling electrodes (21) is the pitch length, and the width of the fixed grating plate coupling electrode (21) coupled with the moving grating plate transmitting electrode (11) is less than or equal to 1 / 2 times the pitch length. Among the plurality of trapezoidal structures of the moving grating plate transmitting electrode (11), the center distance between two trapezoidal structures is 1 / 8 times the pitch length.
4. The electrode structure of a capacitance grating displacement sensor according to claim 3, characterized in that, Among the plurality of mutually inverted trapezoidal structures of the moving grating plate transmitting electrode (11), the length of the long bottom side of the trapezoid is greater than 1 / 8 times the pitch length.
5. The electrode structure of a capacitance grating displacement sensor according to claim 2, wherein, Among the plurality of mutually inverted trapezoidal structures of the moving grating plate transmitting electrode (11), the connection line from the edge of the short bottom side of one trapezoidal structure to the edge of the long bottom side of the adjacent inverted trapezoidal structure is parallel to the edge of the fixed grating plate coupling electrode (21).
6. The electrode structure of a capacitive grating displacement sensor according to claim 1, characterized in that A moving grating plate receiving electrode (12) is further provided on the moving grating plate (1).