Capacitive grating displacement sensor

Abstract

The application provides a capacitive grating displacement sensor. By making the offset amounts of the reflection electrode strips relative to the corresponding first reference not equal, the pitch limited by the process limit is dispersed into multiple offset amounts, thereby breaking through the physical limit of the traditional pitch, and enabling the capacitive grating displacement sensor to realize higher-precision displacement measurement under the same process condition. Meanwhile, the adjustable design of the transmission electrode array and / or the reflection electrode strip can adjust the offset amount of the transmission electrode array and the reflection electrode strip according to the required measurement precision, so that the measurement precision of the capacitive grating displacement sensor is adjustable, and the performance and efficiency are synergistically optimized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of capacitive displacement measurement, in particular to a capacitive grating displacement sensor. BACKGROUND

[0002] Capacitive grating sensors are widely used in various displacement detection gauges. However, due to the limitations of manufacturing and assembly technologies, the reduction space of the grating pitch of the capacitive grating sensor is very limited, which makes it difficult for the phase-discrimination capacitive grating sensor displacement measurement system to achieve higher resolution displacement measurement. SUMMARY

[0003] The technical problem solved by the present application is to provide a capacitive grating displacement sensor to solve the problem that the phase-discrimination capacitive grating sensor displacement measurement system in the prior art is difficult to achieve higher resolution displacement measurement.

[0004] To solve the above technical problem, the first technical solution provided by the present application is to provide a capacitive grating displacement sensor, which comprises:

[0005] A first grating plate comprises a first carrier and a plurality of transmitting electrode arrays, each of which comprises a plurality of transmitting electrodes arranged in a first pitch period along a preset direction;

[0006] A second grating plate comprises a second carrier and a reflecting electrode, wherein the reflecting electrode comprises a reflecting electrode strip;

[0007] The transmitting electrode array is adjustably arranged on the first carrier, and / or the reflecting electrode strip is adjustably arranged on the second carrier.

[0008] In the preset direction, the offset of each reflecting electrode strip relative to the same position of the transmitting electrode in each transmitting electrode array as a first reference is not equal, and the offset is adjustable.

[0009] In some embodiments, the first grating plate further comprises a plurality of first substrates, each of which is equipped with one of the transmitting electrode arrays, and the offset is adjusted by adjusting the relative displacement of the first substrate and the first carrier along the preset direction.

[0010] In the preset direction, the width of the transmitting electrode is equal to the width of the corresponding reflecting electrode strip.

[0011] In some embodiments, the first substrate is in sliding connection with the first carrier, or the first substrate is detachably arranged on the first carrier to realize replacement of the first substrate.

[0012] In some embodiments, the first carrier has a first assembly scale extending along the preset direction, and a mounting position of the first substrate is determined based on the first assembly scale; a line width and a line distance of the first assembly scale are equal to a width of the transmission electrode.

[0013] In some embodiments, each of the transmission electrode arrays corresponds to at least one of the reflection electrode strips; and each of the transmission electrode arrays corresponds to a reflection electrode group composed of the reflection electrode strips.

[0014] The second grid plate further comprises a second substrate, and each of the second substrates is assembled with one of the reflection electrode groups; and the offset is adjusted by adjusting a relative displacement of the second substrate and the second carrier along the preset direction.

[0015] When the reflection electrode group comprises a plurality of the reflection electrode strips, the reflection electrode strips are arranged in a second pitch period, and the second pitch is an integer multiple of the first pitch.

[0016] In some embodiments, the second carrier has a second assembly scale extending along the preset direction, and a mounting position of the second substrate is determined based on the second assembly scale; a line width and a line distance of the second assembly scale are equal to a width of the reflection electrode strip.

[0017] In some embodiments, each of the transmission electrode arrays corresponds to a reflection electrode group composed of the reflection electrode strips; the transmission electrode arrays are arranged in a third pitch period; the third pitch is n times of the first pitch, and n is an integer; and a center distance between any adjacent reflection electrode groups in the preset direction is greater than n times of the first pitch and less than n+1 times of the first pitch.

[0018] In some embodiments, each of the transmission electrode arrays corresponds to a reflection electrode group composed of the reflection electrode strips; the reflection electrode groups are arranged in a fourth pitch period along the preset direction; the fourth pitch is m times of the first pitch, and m is an integer; and a center distance between any adjacent transmission electrode arrays in the preset direction is greater than m-1 times of the first pitch and less than m times of the first pitch.

[0019] In some embodiments, each of the transmission electrode arrays corresponds to a reflection electrode group composed of the reflection electrode strips; and a reflection electrode strip at a same position in each of the reflection electrode groups is defined as a second reference.

[0020] In the preset direction, the second references relative to the offset of the corresponding first reference form an arithmetic sequence, and a common difference of the arithmetic sequence is determined by a ratio of the first pitch to a total number of the transmission electrode arrays.

[0021] In some embodiments, the phase of the excitation signal of each of the transmitting electrode arrays is uniformly distributed within a preset period.

[0022] The beneficial effects of this application are as follows: Unlike existing technologies, this application provides a capacitive grating displacement sensor, comprising a first grating plate and a second grating plate. The first grating plate includes a first stage and multiple transmitting electrode arrays, each transmitting electrode array including multiple transmitting electrodes arranged periodically at a first pitch along a preset direction. The second grating plate includes a second stage and a reflecting electrode; the reflecting electrode includes a reflecting electrode strip. The transmitting electrode arrays are adjustablely disposed on the first stage, and / or the reflecting electrode strips are adjustablely disposed on the second stage. In the preset direction, using the transmitting electrodes at the same position in each transmitting electrode array as a first reference, the offsets of each reflecting electrode strip relative to the corresponding first reference are unequal, and the offsets are adjustable. By making the offsets of each reflecting electrode strip relative to the corresponding first reference unequal, the pitch limited by the manufacturing process is dispersed into multiple offsets, thereby overcoming the physical limitations of traditional pitch and enabling the capacitive grating displacement sensor to achieve higher precision displacement measurement under the same manufacturing process conditions. Meanwhile, the adjustable design of the emitting electrode array and / or reflective electrode strip allows for adjustment of the offset between the emitting electrode array and the reflective electrode strip according to the required measurement accuracy, making the measurement accuracy of the capacitive displacement sensor adjustable and achieving synergistic optimization of performance and efficiency. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0024] Figure 1 This is a schematic diagram of the structure of the first embodiment of the capacitive displacement sensor provided in this application.

[0025] Figure 2 for Figure 1 A schematic diagram showing the relative positions of the emitting electrode array and the reflecting electrode strips;

[0026] Figure 3 This is a schematic diagram of the structure of a second embodiment of the capacitive displacement sensor provided in this application.

[0027] Figure 4 This is a schematic diagram of the third embodiment of the capacitive displacement sensor provided in this application.

[0028] Figure 5 This is a schematic diagram of the structure of the fourth embodiment of the capacitive grating displacement sensor provided in this application.

[0029] Figure 6 This is a schematic diagram of the structure of the fifth embodiment of the capacitive displacement sensor provided in this application.

[0030] Figure 7 A schematic diagram of the structure of a first embodiment of a measurement group provided in this application;

[0031] Figure 8 A schematic diagram of the structure of a second embodiment of a measurement group provided in this application;

[0032] Figure 9 A schematic diagram of the structure of a third embodiment of a measurement group provided in this application;

[0033] Figure 10 This is a schematic diagram of the equivalent circuit between the first gate plate and the second gate plate provided in an embodiment of this application;

[0034] Figure 11 for Figure 10 A schematic diagram showing the coupling capacitance-displacement relationship between each emitting electrode array and the reflecting electrode.

[0035] Figure 12 This is a schematic diagram of the sixth embodiment of the capacitive displacement sensor provided in this application.

[0036] Figure 13 This is a schematic diagram of the structure of an embodiment of the second grid plate provided in this application.

[0037] Figure 14 This is a schematic diagram of the structure of the seventh embodiment of the capacitive displacement sensor provided in this application.

[0038] Figure 15 A schematic diagram of the structure of the emitting electrode array, the reflecting electrode strip, and the first assembly scale provided in the embodiments of this application;

[0039] Figure 16 A schematic diagram of the structure of the transmitting electrode array, the reflecting electrode strip, and the first assembly scale provided in the second embodiment of this application;

[0040] Figure 17 A schematic diagram of the structure of the emitting electrode array, the reflecting electrode strip, and the first assembly scale provided in the third embodiment of this application;

[0041] Figure 18 A schematic diagram of the structure of the emitting electrode array, the reflecting electrode strip, and the first assembly scale provided in the fourth embodiment of this application;

[0042] Figure 19 This is a schematic diagram of an embodiment of the capacitive displacement sensor provided in this application.

[0043] BRIEF DESCRIPTION OF DRAWINGS

[0044] 1, Capacitive displacement sensor; 100, first grating plate; 110, first carrier; 10, transmitting electrode array; 101, transmitting electrode group; 11, transmitting electrode; 12, receiving electrode; 13, connecting bridge; 14, first substrate; 15, first assembly scale; 200, second grating plate; 210, second carrier; 20, reflecting electrode; 201, second substrate; 21, reflecting electrode strip; 22, reflecting electrode group; 23, reflecting electrode block; 24, second assembly scale; 300, flexible circuit board; 400, printed circuit board; L1, first pitch; L2, second pitch; L3, third pitch; L4, fourth pitch; C1 / C2 / C3 / C4 / C0, coupling capacitor. DETAILED DESCRIPTION

[0045] The scheme of the embodiments of the present application will be described in detail below with reference to the accompanying drawings of the description.

[0046] In the following description, specific details are set forth such as particular system configurations, interfaces, techniques, etc., in order to provide a thorough understanding of the present application. However, techniques have been described with reference to the drawings, the description of which is intended to be clear enough to those skilled in the art.

[0047] The technical scheme in the embodiments of the present application will be described clearly and completely below with reference to the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0048] The terms "first", "second", "third" in the present application are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first", "second", "third" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise explicitly specified. All directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present application are only used to explain the relative positional relationship, movement condition, etc. between the components in a certain posture (as shown in the drawings), and if the certain posture changes, the directional indications also change accordingly. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device including a series of steps or units is not limited to the listed steps or units, but can optionally include steps or units not listed, or can optionally include other steps or units inherent to the process, method, product or device.

[0049] Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily mutually exclusive of one another. As will be apparent to those of ordinary skill in the art, embodiments described herein can be combinable with other embodiments.

[0050] In the prior art, a capacitive grating sensor includes a slave grating and a master grating which are parallel to each other but not in contact, the slave grating has a transmitting electrode and a receiving electrode, and the master grating has a reflecting electrode and a shielding electrode. The relative displacement of the slave grating and the master grating changes the coupling capacitance between the transmitting electrode and the reflecting electrode to cause the phase shift of the signal between the receiving electrode and the transmitting electrode, and the phase-shifted electrical signal is sent out through a data processing circuit to calculate the relative displacement.

[0051] According to the measurement mechanism of the active phase-discrimination capacitive grating technology, the phase difference obtained through the phase-discrimination operation is not completely in linear proportion to the displacement variation of the grating of the capacitive grating sensor, but has a deviation of about 0.1%. Therefore, a lower resolution needs to be used to ensure a certain output accuracy. In addition, the frequency of the driving signal has a strong electrical correlation with the area of the grating in the capacitive grating sensor. In order to adapt to the impedance matching requirement of the capacitive grating sensor and the chip, while taking into account low power consumption and having a certain resolution, the driving frequency of the capacitive grating sensor is usually set to be between 200 Hz and 500 Hz, and the working frequency of the chip is set to be between 100 kHz and 300 kHz, which also makes the resolution of the measurement system lower. If the resolution is to be improved, the grating pitch of the capacitive grating sensor needs to be reduced.

[0052] However, due to the limitations of manufacturing, assembly and other technologies, the space for reducing the grating pitch of the capacitive grating sensor is very limited, which makes it difficult for the phase-discrimination capacitive grating displacement measurement system to achieve higher resolution displacement measurement.

[0053] Please refer to Figure 1 and Figure 2 , Figure 1 the structure schematic diagram of the capacitive grating displacement sensor provided by the embodiment of the application, Figure 2 for Figure 1 the relative position schematic diagram of the transmitting electrode array and the reflecting electrode strip in

[0054] To solve the above technical problems, the application provides a capacitive grating displacement sensor 1, which comprises a first grating plate 100 and a second grating plate 200. The first grating plate 100 comprises a transmitting electrode group 101, the transmitting electrode group 101 comprises a plurality of transmitting electrode arrays 10 arranged along a first direction; each transmitting electrode array 10 comprises a plurality of transmitting electrodes 11 arranged periodically along the first direction; the second grating plate 200 comprises a reflecting electrode 20; the reflecting electrode 20 comprises a plurality of reflecting electrode strips 21; wherein one transmitting electrode group 101 and one reflecting electrode 20 constitute a measurement group; in the measurement group, in the first direction, the offset of each reflecting electrode strip 21 relative to the corresponding first reference is not equal.

[0055] By making the offset of each reflecting electrode strip 21 relative to the corresponding first reference in the measurement group not equal, the pitch limited by the process is dispersed into a plurality of offsets in the measurement group, thereby breaking through the physical limitation of the traditional pitch and enabling the capacitive grating displacement sensor 1 to realize higher precision displacement measurement under the same process condition.

[0056] The first direction is a straight vector direction. The first direction is parallel to the measurement direction.

[0057] During the measurement process, the first grating plate 100 and the second grating plate 200 have a relative displacement along the measurement direction.

[0058] One of the first grating plate 100 and the second grating plate 200 is a fixed grating, and the other is a moving grating.

[0059] Exemplarily, the first grating plate 100 is a fixed grating, and the second grating plate 200 is a moving grating.

[0060] The first grating plate 100 and the second grating plate 200 are arranged in a spaced manner in a direction perpendicular to the plate surface direction of the first grating plate 100.

[0061] The number of transmitting electrode arrays 10 in each reflecting electrode group 22 can be equal or not equal, which is selected according to actual needs.

[0062] Exemplarily, all the transmitting electrode arrays 10 in the transmitting electrode group 101 are arranged along the first direction, and are aligned along the two ends perpendicular to the first direction.

[0063] In other embodiments, the transmitting electrode arrays 10 in the transmitting electrode group 101 are arranged in a spaced manner along the first direction, and at least part of the adjacent two transmitting electrode arrays 10 are arranged in a staggered manner along the direction perpendicular to the first direction.

[0064] In the measurement group, each reflecting electrode strip 21 spans the corresponding transmitting electrode array 10.

[0065] The array of transmitting electrodes 10 further comprises connection bridges 13. The connection bridges 13 are used to connect adjacent transmitting electrodes 11, so as to electrically connect each transmitting electrode 11 in the array of transmitting electrodes 10, to facilitate receiving the excitation signal.

[0066] The connection bridges 13 are located in different layers from the transmitting electrodes 11, to avoid the connection bridges 13 affecting the coupling effect between the transmitting electrodes 11 and the corresponding reflecting electrodes 20.

[0067] The set of transmitting electrodes 101 is at least one.

[0068] Exemplarily, as shown in the figure, the set of transmitting electrodes 101 is one. Figure 1

[0069] In some embodiments, the number of the set of transmitting electrodes 101 is multiple, and / or the number of the reflecting electrodes 20 is multiple, so that all the sets of transmitting electrodes 101 and all the reflecting electrodes 20 form multiple measurement groups with different measurement precisions; the first grating plate 100 further comprises at least one receiving electrode 12 arranged along a first direction; in a direction perpendicular to the plate surface of the first grating plate 100, the reflecting electrodes 20 are partially overlapped with the corresponding receiving electrodes 12; the set of transmitting electrodes 101 is located at the side of the receiving electrode 12 along a second direction, and the first direction and the second direction are arranged perpendicularly.

[0070] The design of the multiple measurement groups with different measurement precisions makes the measurement precision of the grating displacement sensor 1 selectable, so that the measurement precision can be flexibly selected according to the application requirements, to realize the collaborative optimization of performance and efficiency.

[0071] The transmitting electrode 11 is applied with an excitation signal. An electric field is generated around the transmitting electrode 11 and is projected onto the corresponding reflecting electrode 20. The reflecting electrode 20 is arranged floating, i.e., the reflecting electrode 20 is not electrified. Although the reflecting electrode 20 is not electrified, it is a conductor. According to the principle of electromagnetism, the electric field will induce electric charges on these floating reflecting electrodes 20, so that an electric potential is generated. The reflecting electrode 20 with the induced electric potential itself also becomes a field source, which emits an electric field. At this time, the receiving electrode 12 induces a current / voltage signal based on the electric field returned from the reflecting electrode 20. The signal strength induced by the receiving electrode 12 depends on the overlapping area between the transmitting electrode 11, the reflecting electrode 20 and the receiving electrode 12. The larger the overlapping area, the stronger the electric field coupling, and the stronger the received signal.

[0072] The partial overlapping design of the receiving electrode 12 and the reflecting electrode 20 enhances the capacitive coupling effect.

[0073] Exemplarily, the overlapping area between the reflecting electrode 20 and the corresponding receiving electrode 12 is partially in a block structure, to further enhance the capacitive coupling effect between the receiving electrode 12 and the reflecting electrode 20 and the sensitivity of the capacitive change.​

[0074] In the measurement group, the reflective electrode strip 21 is arranged to extend along the second direction and is arranged to be spaced along the first direction.

[0075] One measurement group corresponds to one receiving electrode 12. The measurement groups can share the same receiving electrode 12 or correspond to different receiving electrodes 12.

[0076] When the transmitting electrode group 101 is multiple, the multiple transmitting electrode groups 101 work in time division to reduce signal interference.

[0077] Please participate Figures 3 to 6 , Figure 3 A structure diagram of a second embodiment of the capacitive grating displacement sensor provided by the embodiment of the application is shown in the figure, Figure 4 A structure diagram of a third embodiment of the capacitive grating displacement sensor provided by the embodiment of the application is shown in the figure, Figure 5 A structure diagram of a fourth embodiment of the capacitive grating displacement sensor provided by the embodiment of the application is shown in the figure, Figure 6 A structure diagram of a fifth embodiment of the capacitive grating displacement sensor provided by the embodiment of the application is shown in the figure.

[0078] As Figure 3 shown in the figure, in the first specific embodiment, the transmitting electrode group 101 is two and is located on the same side of the receiving electrode 12; the reflective electrode 20 is one.

[0079] The two transmitting electrode groups 101 and the one reflective electrode 20 can respectively constitute two measurement groups.

[0080] The two measurement groups share the same receiving electrode 12 and the same reflective electrode 20 to reduce the number of the receiving electrode 12 and the reflective electrode 20, thereby saving cost.

[0081] Exemplarily, in the first measurement group, each transmitting electrode array 10 corresponds to two reflective electrode strips 21, and the corresponding two reflective electrode strips 21 have the same overlapping area with the respective corresponding transmitting electrode 11 to increase the coupling effect between the transmitting electrode 11 and the reflective electrode 20. In the second measurement group, each transmitting electrode array 10 corresponds to one reflective electrode strip 21, and the offsets of the reflective electrode strips 21 relative to the corresponding first reference are not equal.

[0082] The two measurement groups correspond to different measurement accuracies for the user to select.

[0083] As Figure 4 and Figure 5As shown in the second specific embodiment, the transmitting electrode group 101 is two, and is located on opposite sides of the receiving electrode 12 respectively; wherein the reflecting electrode 20 is two, the two reflecting electrodes 20 are arranged at intervals, and correspond to the same receiving electrode 12; or, the reflecting electrode 20 is one, and the reflecting electrode 20 sequentially spans a transmitting electrode group 101, a receiving electrode 12 and another transmitting electrode group 101.

[0084] The transmitting electrode group 101 is two, and can constitute two measurement groups.

[0085] The two transmitting electrode groups 101 are respectively located on opposite sides of the receiving electrode 12 along the second direction, so as to reduce the spacing between the transmitting electrode group 101 and the receiving electrode 12, thereby reducing the extension length of the reflecting electrode strip 21 along the second direction, reducing the impedance and enhancing the coupling effect.

[0086] As shown in the second specific embodiment, the transmitting electrode group 101 is two, and is located on opposite sides of the receiving electrode 12 respectively; wherein the reflecting electrode 20 is two, the two reflecting electrodes 20 are arranged at intervals, and correspond to the same receiving electrode 12; or, the reflecting electrode 20 is one, and the reflecting electrode 20 sequentially spans a transmitting electrode group 101, a receiving electrode 12 and another transmitting electrode group 101. Figure 4 As shown in some embodiments, the reflecting electrode 20 is two, the two reflecting electrodes 20 are arranged at intervals, and correspond to the same receiving electrode 12, so as to reduce the number of receiving electrodes 12 and save costs; and each transmitting electrode group 101 corresponds to a different reflecting electrode 20, so as to reduce interference.

[0087] As shown in some embodiments, the reflecting electrode 20 is two, the two reflecting electrodes 20 are arranged at intervals, and correspond to the same receiving electrode 12, so as to reduce the number of receiving electrodes 12 and save costs; and each transmitting electrode group 101 corresponds to a different reflecting electrode 20, so as to reduce interference. Figure 5 As shown in another embodiment, the reflecting electrode 20 is one, and the reflecting electrode 20 sequentially spans a transmitting electrode group 101, a receiving electrode 12 and another transmitting electrode group 101, so that the two measurement groups share the same receiving electrode 12, facilitating the preparation of the receiving electrode 12.

[0088] As shown in another embodiment, the reflecting electrode 20 is one, and the reflecting electrode 20 sequentially spans a transmitting electrode group 101, a receiving electrode 12 and another transmitting electrode group 101, so that the two measurement groups share the same receiving electrode 12, facilitating the preparation of the receiving electrode 12. Figure 6 As shown in the third specific embodiment, the transmitting electrode group 101 is one; the receiving electrode 12 is two, and is located on opposite sides of the transmitting electrode group 101 respectively; the reflecting electrode 20 is two, and is arranged opposite along the first direction, and is arranged one by one corresponding to the receiving electrode 12.

[0089] The transmitting electrode group 101 and the two receiving electrodes 12 can respectively constitute two measurement groups.

[0090] In the first direction, there is an overlapping area between the two reflecting electrodes 20.

[0091] Exemplarily, in each measurement group, each transmitting electrode array 10 corresponds to a reflecting electrode strip 21. Each transmitting electrode array 10 corresponds to two reflecting electrode strips 21 located in different measurement groups, so that the reflecting electrode strips 21 in the two reflecting electrodes 20 are arranged alternately in the first direction. This design not only can reduce the number of transmitting electrode arrays 10, but also can reduce the extension length of the reflecting electrode strip 21 along the second direction, thereby enhancing the coupling effect.

[0092] In other embodiments, one reflective electrode strip 21 in each measurement group can correspond to one or more reflective electrode strips 21.

[0093] In other embodiments, the capacitive displacement sensor 1 can further include more than two measurement groups, which can be selected according to actual needs. For example, the receiving electrode 12 is one, and the transmitting electrode groups 101 are four. Two transmitting electrode groups 101 are located on one side of the receiving electrode 12 and are arranged side by side along the first direction or the second direction. The other two transmitting electrode groups 101 are located on the other side of the receiving electrode 12 and are arranged side by side along the first direction or the second direction.

[0094] In some embodiments, in the same measurement group, in the first direction, the width of the transmitting electrode 11 is equal to the width of the reflective electrode strip 21, and the plurality of transmitting electrodes 11 in the transmitting electrode array 10 are periodically arranged at a first pitch L1. Each transmitting electrode array 10 corresponds to at least one reflective electrode strip 21. Each transmitting electrode array 10 corresponds to a reflective electrode strip 21 which constitutes a reflective electrode group 22. When the reflective electrode group 22 of the same measurement group includes a plurality of reflective electrode strips 21, the reflective electrode strips 21 are periodically arranged at a second pitch L2, and the second pitch L2 is an integer multiple of the corresponding first pitch L1.

[0095] The first pitch L1 is the center-to-center distance of two adjacent transmitting electrodes 11 in the same transmitting electrode array 10 in the measurement direction. The first pitch L1 can also be called the grid pitch.

[0096] Exemplarily, in each transmitting electrode group 101, the size and shape of each transmitting electrode 11 are equal, and each transmitting electrode 11 in the same transmitting electrode array 10 is arranged at equal intervals. In the transmitting electrode array 10, the distance between adjacent transmitting electrodes 11 is equal to the width of the transmitting electrode 11. That is, the first pitch L1 is twice the distance between adjacent transmitting electrodes 11.

[0097] In other embodiments, in the transmitting electrode array 10, the distance between adjacent transmitting electrodes 11 and the width of the transmitting electrode 11 can not be equal.

[0098] Through the periodic arrangement and directional arrangement of the reflective electrode strips 21, the capacitive coupling efficiency can be effectively improved, and a more accurate corresponding relationship between the displacement change and the capacitance change can be established.

[0099] The equal-width design of the reflective electrode strip 21 and the transmitting electrode 11 helps to maintain the stability of the capacitive coupling.

[0100] When the reflective electrode group 22 includes a plurality of reflective electrode strips 21, the multiple relationship of the second pitch L2 relative to the first pitch L1 can realize periodic enhancement of the signal, and provide a more reliable electrical basis for high-precision displacement detection. At the same time, the signal acquisition effect can be optimized by adjusting the pitch ratio of the transmitting electrode array 10 and the reflective electrode strip 21.

[0101] Exemplarily, the second pitch L2 is greater than the first pitch L1, which can reduce the difficulty of preparation of the reflective electrode strip 21.

[0102] In some embodiments, the transmitting electrode group 101 is multiple, and the capacitive grating displacement sensor 1 further includes a control circuit (not shown in the figure), which is configured to control the independent work of each transmitting electrode group 101; in each measurement group, the reflective electrode strip 21 at the same position in each reflective electrode group 22 is defined as a second reference, and in the first direction, the offset of each second reference relative to the corresponding first reference constitutes a sequence, and the non-zero term with the smallest absolute value in each sequence is defined as a reference term; the reference terms of each measurement group are different from each other.

[0103] When selecting which measurement group to measure, the control circuit controls the corresponding transmitting electrode group 101 to work, so as to reduce the interference between signals.

[0104] The reference term determines the measurement accuracy of the measurement group.

[0105] Exemplarily, as Figure 3As shown, the four transmitting electrode arrays 10 in one transmitting electrode group 101 and the two transmitting electrode arrays 10 in another transmitting electrode group 101 are taken as an example for description. In the first measurement group, each transmitting electrode array 10 corresponds to two reflective electrode strips 21, and the two corresponding reflective electrode strips 21 have the same overlapping area with the corresponding transmitting electrode 11, that is, the reflective electrode group 22 in the first measurement group includes two reflective electrode strips 21. In the second measurement group, each transmitting electrode array 10 corresponds to one reflective electrode strip 21, that is, the reflective electrode group 22 in the second measurement group includes one reflective electrode strip 21. In the first measurement group, the reflective electrode strips 21 in one reflective electrode group 22 are completely overlapped with the corresponding transmitting electrode 11, and the reflective electrode strips 21 in the other reflective electrode group 22 are respectively located between the transmitting electrodes 11. Taking the first transmitting electrode 11 in each transmitting electrode array 10 as the first reference and the first reflective electrode strip 21 in the reflective electrode group 22 as the second reference, the sequence includes 0, L1 / 2 in turn. Taking the second reflective electrode strip 21 in the reflective electrode group 22 as the second reference, the sequence includes L2, L2+L1 / 2 in turn. The reference in the first measurement group is L1 / 2, that is, the measurement accuracy of the first measurement group is L1 / 2. In the second measurement group, the offset of each reflective electrode 20 from the first transmitting electrode 11 in the corresponding transmitting electrode array 10 is 0, L1 / 4, L1 / 2, 3L1 / 4 in turn, and the reference is L1 / 4, that is, the measurement accuracy of the second measurement group is L1 / 4.

[0106] Please refer to Figures 7 to 9 , Figure 7 FIG. 1 is a structural schematic diagram of a measurement group according to a first embodiment provided by the present application, Figure 8 FIG. 2 is a structural schematic diagram of a measurement group according to a second embodiment provided by the present application, Figure 9 FIG. 3 is a structural schematic diagram of a measurement group according to a third embodiment provided by the present application.

[0107] As Figure 7 shown, in some embodiments, in the measurement group, the transmitting electrode arrays 10 are periodically arranged at a third pitch L3, the third pitch L3 is n times of the first pitch L1, and n is an integer. In the first direction, the center distance between any two adjacent reflective electrode groups 22 is greater than n times of the first pitch L1 and less than (n+1) times of the first pitch L1.

[0108] The structures of the transmitting electrode arrays 10 in the single measurement group are all the same.

[0109] Exemplarily, in the first direction, the center distance between any two adjacent reflective electrode groups 22 is equal and is nL+L1 / 4.

[0110] In other embodiments, as Figure 8As shown, in the first direction, the center distance between any two adjacent reflective electrode groups 22 may not be equal.

[0111] By limiting the center distance between any two adjacent reflective electrode groups 22 to be greater than n times the first pitch L1 and less than n+1 times the first pitch L1, the absolute value of the offset of the second reference relative to the corresponding first reference can be controlled within the length of the first pitch L1, thereby maximizing the range and minimizing the number of emitting electrodes 11 in the emitting electrode array 10.

[0112] like Figure 9 As shown, in some other embodiments, in the measurement group, the reflective electrode group 22 is arranged periodically along the first direction at a fourth pitch L4, where the fourth pitch L4 is m times the corresponding first pitch L1, and m is an integer. In the first direction, the center distance between any adjacent emitting electrode array 10 is greater than m-1 times the first pitch L1 and less than m times the first pitch L1.

[0113] Each emission electrode array 10 in a single measurement group has the same structure.

[0114] For example, in the first direction, the center-to-center spacing between any adjacent emitting electrode arrays 10 is equal and is mL-L1 / 4.

[0115] By limiting the center spacing between any two adjacent emitter electrode arrays 10 to be greater than m-1 times the first pitch L1 and less than m times the first pitch L1, the absolute value of the offset of the second reference relative to the corresponding first reference can be controlled within the length of the first pitch L1, thereby maximizing the range and minimizing the number of emitter electrodes 11 in the emitter electrode array 10.

[0116] In other embodiments, the center-to-center spacing between any adjacent emitter electrode arrays 10 may be unequal.

[0117] In other embodiments, the center-to-center spacing between any adjacent emitting electrode arrays 10 may be unequal, and the center-to-center spacing between any adjacent reflective electrode groups 22 may be unequal.

[0118] In some embodiments, in at least one measurement group, in a first direction, the offset of each second reference relative to the corresponding first reference forms an arithmetic sequence, and the tolerance of the arithmetic sequence is determined by the ratio of the corresponding first pitch L1 to the total number of the emission electrode arrays 10 of the corresponding emission electrode group 101.

[0119] The offset can be positive or negative.

[0120] In a single measurement group, the absolute value of the tolerance of the arithmetic sequence is the ratio of the value of the first pitch L1 to the total number of the corresponding transmitting electrode array 10.

[0121] Exemplarily, as shown in Figure 3 and Figure 7 Taking the second measurement group as an example, the first electrode 11 in each transmitting electrode array 10 is taken as the first reference, and the offset of each second reference relative to the corresponding first reference forms an arithmetic sequence including 0, L1 / 4, L1 / 2, 3L1 / 4 in turn.

[0122] Please refer to Figure 1 , Figure 10 and Figure 11 , Figure 10 The equivalent circuit schematic diagram between the first grid plate and the second grid plate provided by the embodiment of the present application is shown in Figure 11 is Figure 10 The coupling capacitance-displacement correspondence relationship between each transmitting electrode array and the reflecting electrode in

[0123] In some embodiments, in each measurement group, the phases of the excitation signals of the transmitting electrode arrays 10 are uniformly distributed in a preset period.

[0124] Exemplarily, the preset period is π.

[0125] The uniform distribution of the phases of the excitation signals of the transmitting electrode arrays 10 in the preset period means that the phases of the multiple excitation signals are distributed with equal intervals, for example Figure 1 The phase difference of the excitation signals of the four transmitting electrode arrays 10 in the measurement group in is π / 4. This distribution mode uniformly divides the preset period by the phase difference, so that the excitation signals of the transmitting electrode arrays 10 form equal-angle intervals on the time axis.

[0126] In other embodiments, the preset period can be other values.

[0127] Exemplarily, multiple signal sources are used to generate sine waves or cosine waves with fixed phase differences. For example, the signal source is a voltage source.

[0128] Exemplarily, the number of signal sources is the same as the number of transmitting electrode arrays 10.

[0129] In other embodiments, the excitation signals with specific phase relationships can also be generated through digital signal processing.

[0130] Each of the transmission electrode arrays 10 and the corresponding receiving electrode 12 forms a coupling capacitor, denoted as C1, C2, C3, C4 in turn. When the first grid plate 100 and the second grid plate 200 are relatively displaced, the values of the capacitors change accordingly (for example, from C1=c, C2=c / 2, C3=0, C4=c / 2 when the displacement is 0 to C1=c / 2, C2=c, C3=c / 2, C4=0 when the displacement is L1 / 4). At the same time, the excitation signals of each of the transmission electrode arrays 10 have a certain phase difference, so that the signals transmitted to the receiving electrode 12 through the coupling capacitors not only have amplitudes modulated by the values of the capacitors, but also have different phases. The four signals are vectorially superimposed on the receiving electrode 12 through the receiving coupling capacitor C0 to form a composite signal, the amplitude and phase of which comprehensively reflect the relative displacement information, and the accurate detection of the displacement is realized.

[0131] When the displacement is a non-zero integer multiple of L1, each of the coupling capacitors is the same as the coupling capacitor when the displacement is 0, thereby forming a cycle period. The integer period part of the displacement can be determined by counting the cycle period, and then the fine displacement value in the cycle can be obtained according to the corresponding coupling capacitors of each of the transmission electrode arrays 10 and by querying the coupling capacitor-displacement pair relationship table.

[0132] By uniformly distributing the phases of the excitation signals in the cycle period, the capacitive grid displacement sensor 1 can obtain more uniform capacitive coupling characteristics when the displacement changes, and reduce the errors caused by uneven phase distribution. This phase distribution mode can improve the stability of signal acquisition, so that the phase difference change can be more accurately captured by the phase detection circuit, thereby improving the resolution and accuracy of displacement measurement. At the same time, uniform phase distribution helps to reduce the mutual interference between multiple excitation signals, enhances the anti-noise capability, and further realizes more reliable displacement detection.

[0133] Referring to Figure 12 , Figure 12 a structure diagram of a sixth embodiment of the capacitive grid displacement sensor provided by the present application.

[0134] The present application also provides a capacitive grid displacement sensor 1. The capacitive grid displacement sensor 1 comprises a first grid plate 100 and a second grid plate 200. The first grid plate 100 comprises a first carrier 110 and a plurality of transmission electrode arrays 10, each of which comprises a plurality of transmission electrodes 11 arranged periodically at a first pitch L1 in a predetermined direction; the second grid plate 200 comprises a second carrier 210 and a reflection electrode 20; the reflection electrode 20 comprises a reflection electrode strip 21; wherein the transmission electrode arrays 10 are adjustably arranged on the first carrier 110, and / or the reflection electrode strip 21 is adjustably arranged on the second carrier 210; in the predetermined direction, the offset of each of the reflection electrode strips 21 relative to the corresponding first reference, i.e., the transmission electrode 11 at the same position in each of the transmission electrode arrays 10, is not equal, and the offset is adjustable.

[0135] By making the offset amounts of the reflection electrode strips 21 relative to the corresponding first reference not equal, the pitch limited by the process is dispersed into multiple offset amounts, thereby breaking through the physical limit of the traditional pitch and enabling the capacitive grating displacement sensor 1 to achieve higher precision displacement measurement under the same process condition. Meanwhile, the adjustable design of the transmission electrode array 10 and / or the reflection electrode strip 21 can adjust the offset amount of the transmission electrode array 10 and the reflection electrode strip 21 according to the required measurement precision, so that the measurement precision of the capacitive grating displacement sensor 1 is adjustable, achieving the synergistic optimization of performance and efficiency.

[0136] The number of the transmission electrodes 11 in each transmission electrode array 10 can be the same or different, which is not limited here and can be selected according to actual needs.

[0137] The preset direction is a straight vector direction. The preset direction is parallel to the measurement direction. The preset direction is the first direction.

[0138] During the measurement process, the first grating plate 100 and the second grating plate 200 have a relative displacement along the measurement direction.

[0139] One of the first grating plate 100 and the second grating plate 200 is a fixed grating, and the other is a moving grating.

[0140] In some embodiments, the first grating plate 100 further includes a plurality of first substrates 14, each of which is equipped with a transmission electrode array 10. By adjusting the relative displacement of the first substrate 14 and the first carrier 110 along the preset direction, the offset amount is adjusted. In the preset direction, the width of the transmission electrode 11 is equal to the width of the corresponding reflection electrode strip 21.

[0141] The transmission electrode array 10 further includes a connecting bridge 13. The connecting bridge 13 is used to connect adjacent transmission electrodes 11, so that each transmission electrode 11 in the transmission electrode array 10 is electrically connected, so as to facilitate the reception of the excitation signal.

[0142] The connecting bridge 13 and the transmission electrode 11 are located in different layers to avoid affecting the coupling effect between the transmission electrode 11 and the corresponding reflection electrode 20.

[0143] The material of the connecting bridge 13 and the transmission electrode 11 is not limited in the embodiments of the present application and can be selected according to actual needs. For example, the material of the connecting bridge 13 and the transmission electrode 11 can be the same or different.

[0144] In some embodiments, the first grating plate 100 further includes a receiving electrode 12 arranged along the preset direction and arranged on the first carrier 110. In the direction perpendicular to the surface of the first grating plate 100, the reflection electrode 20 and the corresponding receiving electrode 12 are partially overlapped.

[0145] The array of transmitting electrodes 10 is located at the side of the receiving electrode 12 along a second direction, and the preset direction is perpendicular to the second direction.

[0146] The array of transmitting electrodes 10 is arranged on the first substrate 14, which facilitates adjustment of the relative position of the array of transmitting electrodes 10 on the first carrier 110, and the first substrate 14 carrying the array of transmitting electrodes 10 can also prevent deformation of the array of transmitting electrodes 10 from causing inaccurate measurement to some extent. In addition, compared with preparing the array of transmitting electrodes 10 on the first carrier 110 as a whole, the embodiment adjusts the offset by adjusting the relative displacement of the first substrate 14 and the first carrier 110 along the preset direction, so that the positioning of each array of transmitting electrodes 10 is more accurate and the measurement is more accurate.

[0147] The equal-width design of the transmitting electrode 11 and the reflective electrode strip 21 facilitates adjustment of measurement accuracy.

[0148] Exemplarily, the first substrate 14 is rectangular, which facilitates positioning.

[0149] Exemplarily, the first substrate 14 can be provided with positioning marks, which facilitates positioning of the first substrate 14.

[0150] In other embodiments, the first substrate 14 can have other shapes, which are not limited here and can be selected according to actual needs.

[0151] In some embodiments, the first substrate 14 is in sliding connection with the first carrier 110, or the first substrate 14 is detachably arranged on the first carrier 110 to realize replacement of the first substrate 14.

[0152] In a specific embodiment, the first substrate 14 is in sliding connection with the first carrier 110, and the first substrate 14 can at least slide relative to the first carrier 110 along the preset direction. For example, the first substrate 14 can slide along the preset direction, and can also slide along a second direction (not shown) perpendicular to the first direction, so that the first carrier 110 can accommodate more first substrates 14, thereby adjusting more measurement accuracy. Figure 12

[0153] Exemplarily, the first carrier 110 can be provided with a sliding groove or a sliding channel, and the first substrate 14 is assembled in the sliding groove or the sliding channel, so that the first substrate 14 can be limited.

[0154] In another specific embodiment, the first substrate 14 is detachably arranged on the first carrier 110 to realize replacement of the first substrate 14. The first substrate 14 can be connected with the first carrier 110 in a buckle, plug-in, magnetic attraction or threaded connection manner.

[0155] ​Exemplarily, a plurality of transmitting electrode groups (not shown in the figure) can be designed, each of which comprises a plurality of transmitting electrode arrays 10. One transmitting electrode group corresponds to one measurement accuracy, and the corresponding transmitting electrode group is directly replaced according to the required accuracy, that is, the assembly position of each transmitting electrode group on the first carrier 110 is a preset position, so that the assembly can be simplified.

[0156] Exemplarily, a plurality of transmitting electrode arrays 10 can be designed, and each transmitting electrode array 10 is assembled according to the required measurement accuracy. That is, the structures of the transmitting electrode arrays 10 assembled on the first carrier 110 can be the same or different.

[0157] In some embodiments, the first carrier 110 has a first assembly scale 15 arranged along a preset direction, and the mounting position of the first substrate 14 is determined based on the first assembly scale 15; the line width and the line spacing of the first assembly scale 15 are equal to the width of the transmitting electrode 11.

[0158] Here, the pattern of the first assembly scale 15 is not limited and can be selected according to actual needs.

[0159] Precise instruments such as microscopes can be used to position the first substrate 14 based on the first assembly scale 15, which can improve the positioning accuracy and measurement accuracy.

[0160] Please refer to Figures 12 to 14 , Figure 13 FIG. 2 is a structural schematic diagram of a second grid plate according to an embodiment of the present application, Figure 14 FIG. 7 is a structural schematic diagram of a capacitive grating displacement sensor according to a seventh embodiment of the present application.

[0161] In other embodiments, each transmitting electrode array 10 corresponds to at least one reflecting electrode strip 21; the reflecting electrode strips 21 corresponding to each transmitting electrode array 10 constitute a reflecting electrode group 22; the second grid plate 200 further comprises a second substrate 201, and each second substrate 201 is assembled with one reflecting electrode group 22; the offset amount is adjusted by adjusting the relative displacement of the second substrate 201 and the second carrier 210 along a preset direction; when the reflecting electrode strips 21 in the reflecting electrode group 22 are multiple, the reflecting electrode strips 21 are periodically arranged with a second pitch L2, and the second pitch L2 is an integer multiple of the first pitch L1.

[0162] When each reflecting electrode group 22 comprises one reflecting electrode strip 21, in the preset direction, the offset amount of each reflecting electrode strip 21 relative to the corresponding first reference is not equal, with the transmitting electrode 11 at the same position in each transmitting electrode array 10 as the first reference.

[0163] As Figure 14As shown, each of the reflective electrode groups 22 includes a plurality of reflective electrode strips 21, and the reflective electrode strips 21 are arranged periodically with a second pitch L2, and the second pitch L2 is an integer multiple of the first pitch L1, so that the reflective electrode strips 21 in the reflective electrode group 22 have the same overlapping area with the corresponding transmitting electrode 11, thereby enhancing the coupling effect and reducing the signal interference between the reflective electrode strips 21. In addition, compared with the preparation of the reflective electrode 20 on the second carrier 210 in a whole piece, the embodiment adjusts the offset by adjusting the relative displacement of the second substrate 201 and the second carrier 210 along the preset direction, so that the positioning of the reflective electrode strips 21 is more accurate, and the measurement is more accurate.

[0164] The reflective electrode strips 21 of the second substrate 201 are connected to each other.

[0165] Exemplarily, as shown, Figure 13 The reflective electrode group 22 on the second substrate 201 assembled on the second carrier 210 is electrically connected to the reflective electrode block 23.

[0166] The reflective electrode block 23 is arranged along the preset direction, so as to facilitate the electrical connection between the reflective electrode group 22 and the reflective electrode block 23.

[0167] Exemplarily, the reflective electrode 20 is partially overlapped with the receiving electrode 12 through the reflective electrode block 23. That is, in the direction perpendicular to the plate surface of the first grid plate 100, the reflective electrode block 23 is at least partially overlapped with the receiving electrode 12.

[0168] The second substrate 201 and the second carrier 210 can be connected in a sliding manner or in a detachable manner, which will not be described in detail herein, and reference can be made to the connection between the first substrate 14 and the first carrier 110.

[0169] The reflective electrode groups 22 can be arranged periodically or not, which can be selected according to actual needs.

[0170] In other embodiments, the capacitive grating displacement sensor 1 includes the first substrate 14 and the second substrate 201 described above, so that the transmitting electrode array 10 and the reflective electrode strip 21 are both adjustable.

[0171] In some embodiments, the second carrier 210 has a second assembly scale 24 arranged along the preset direction, and the mounting position of the second substrate 201 is determined based on the second assembly scale 24; the line width and the line spacing of the second assembly scale 24 are equal to the width of the reflective electrode strip 21.

[0172] The second substrate 201 can be positioned based on the second assembly scale 24 by using a microscope or other precision instruments, so as to improve the positioning accuracy and the measurement accuracy.

[0173] There are no restrictions on the pattern of the second assembly scale 24 here; it can be selected according to actual needs.

[0174] Please see Figures 15 to 18 , Figure 15 This is a schematic diagram of the structure of the emitting electrode array, the reflecting electrode strip, and the first assembly scale provided in the first embodiment of this application. Figure 16 This is a schematic diagram of the structure of the transmitting electrode array, the reflecting electrode strip, and the first assembly scale provided in the second embodiment of this application. Figure 17 This is a schematic diagram of the structure of the transmitting electrode array, the reflecting electrode strip, and the first assembly scale provided in the third embodiment of this application. Figure 18 This is a schematic diagram of the structure of the transmitting electrode array, the reflecting electrode strip, and the first assembly scale provided in the fourth embodiment of this application.

[0175] In some embodiments, each reflective electrode strip 21 corresponding to each emitting electrode array 10 constitutes a reflective electrode group 22; the emitting electrode array 10 is arranged periodically with a third pitch L3; the third pitch L3 is n times the first pitch L1, where n is an integer; in a preset direction, the center distance between any adjacent reflective electrode groups 22 is greater than n times the first pitch L1 and less than n+1 times the first pitch L1.

[0176] Each emitter electrode array 10 has the same structure, and each emitter electrode group 101 has the same structure.

[0177] For example, such as Figure 15 As shown, each emitting electrode group 101 includes one emitting electrode 11 strips, and the center-to-center distance between any two adjacent reflective electrode strips 21 is equal and is nL1+L1 / 4. Specifically, taking the first emitting electrode 11 in each emitting electrode array 10 as the first reference, the offset of each reflective electrode strip 21 relative to the first reference in a preset direction is 0, L1 / 4, L1 / 2, and 3L1 / 4, respectively.

[0178] In other embodiments, the center-to-center spacing between the reflective electrode groups 22 may be unequal, and no particular restrictions are imposed here. For example, as Figure 16 As shown, taking the first emission electrode 11 in each emission electrode array 10 as the first reference, in a preset direction, the offset of each reflection electrode strip 21 relative to the first reference is 0, L1 / 8, L1 / 2, 3L1 / 4 respectively, and the center distance between two adjacent emission electrode strips 11 is nL1+L1 / 8, nL1+3L1 / 8, nL1+L1 / 4 respectively.

[0179] The center distance between any two adjacent reflection electrode groups 22 is defined as greater than n times of the first pitch L1 and less than (n+1) times of the first pitch L1, which can control the absolute value of the offset of the second reference relative to the corresponding first reference within one first pitch L1, and increase the range as much as possible and reduce the number of transmission electrodes 11 in the transmission electrode array 10.

[0180] In some embodiments, as shown in FIG. 1, each reflection electrode strip 21 corresponding to each transmission electrode array 10 constitutes a reflection electrode group 22; the reflection electrode groups 22 are periodically arranged along the preset direction with a fourth pitch L4; the fourth pitch L4 is m times of the first pitch L1, and m is an integer; the center distance between any two adjacent transmission electrode arrays 10 in the preset direction is greater than (m-1) times of the first pitch L1 and less than m times of the first pitch L1.

[0181] The structures of the transmission electrode arrays 10 are the same, and the structures of the transmission electrode groups 101 are the same.

[0182] Exemplarily, as shown in FIG. 2, each transmission electrode group 101 includes one strip of transmission electrodes 11; the center distance between any two adjacent transmission electrode arrays 10 is equal and is mL1-L1 / 4. Figure 17 In other embodiments, the center distance between the transmission electrode arrays 10 can not be equal, which is not limited here.

[0183] The center distance between any two adjacent transmission electrode arrays 10 is defined as greater than (m-1) times of the first pitch L1 and less than m times of the first pitch L1, which can control the absolute value of the offset of the second reference relative to the corresponding first reference within one first pitch L1, and increase the range as much as possible and reduce the number of transmission electrodes 11 in the transmission electrode array 10.

[0184] In other embodiments, the transmission electrode arrays 10 can be arranged at unequal intervals, and the reflection electrode groups 22 can be arranged at unequal intervals.

[0185] In some embodiments, as shown in FIG. 3, each reflection electrode strip 21 corresponding to each transmission electrode array 10 constitutes a reflection electrode group 22; the reflection electrode strips 21 at the same position in each reflection electrode group 22 are defined as second references; the offsets of the second references relative to the corresponding first references in the preset direction constitute an arithmetic sequence, and the common difference of the arithmetic sequence is determined by the ratio of the first pitch L1 to the total number of the transmission electrode arrays 10.

[0186] Figure 16 In some embodiments, as shown in FIG. 3, each reflection electrode strip 21 corresponding to each transmission electrode array 10 constitutes a reflection electrode group 22; the reflection electrode strips 21 at the same position in each reflection electrode group 22 are defined as second references; the offsets of the second references relative to the corresponding first references in the preset direction constitute an arithmetic sequence, and the common difference of the arithmetic sequence is determined by the ratio of the first pitch L1 to the total number of the transmission electrode arrays 10. ​

[0187] Exemplarily, the first one of the transmitting electrode arrays 10 is taken as the first reference, and in the preset direction, the offset of each reflecting electrode strip 21 relative to the first reference is 0, L1 / 4, L1 / 2, 3L1 / 4 in turn.

[0188] In other embodiments, as shown in FIG. 2B, in the preset direction, the offset of each second reference relative to the corresponding first reference forms a non-arithmetic sequence. Figure 18

[0189] In other embodiments, in the plurality of reflecting electrode arrays arranged in turn, the offset of each second reference relative to the first reference can be a monotonic sequence or a non-monotonic sequence. For example, as shown in FIG. 2C, the first one of the transmitting electrode arrays 10 is taken as the first reference, and the offset of each second reference relative to the first reference is 0, 3L1 / 2, 3L1 / 4, L1 / 4 in turn, which forms a non-monotonic sequence. Figure 18

[0190] In some embodiments, as shown in FIG. 3, the phase of the excitation signal of each transmitting electrode array 10 is uniformly distributed in a preset period. Figures 10 to 12

[0191] Exemplarily, the preset period is π.

[0192] The uniform distribution of the phase of the excitation signal of the transmitting electrode array 10 in the preset period means that the phases of the plurality of excitation signals are distributed with equal intervals. This distribution mode uniformly divides the phase difference by the preset period, so that the excitation signals of the transmitting electrode arrays 10 form equal-angle intervals in the time axis.

[0193] In other embodiments, the preset period can be other values.

[0194] Exemplarily, a plurality of signal sources are used to generate sine waves or cosine waves with fixed phase differences.

[0195] Exemplarily, the number of signal sources is the same as the number of transmitting electrode arrays 10.

[0196] In other embodiments, the excitation signals with specific phase relationships can also be generated through digital signal processing.

[0197] ​​​Exemplarily, each transmitting electrode array 10 forms a coupling capacitor with the corresponding receiving electrode 12, denoted as C1, C2, C3, C4 in sequence. When the first grid plate 100 and the second grid plate 200 are relatively displaced, the values of the capacitors change accordingly (for example, from C1=c, C2=c / 2, C3=0, C4=c / 2 when the displacement is 0, to C1=c / 2, C2=c, C3=c / 2, C4=0 when the displacement is L1 / 4). Meanwhile, the excitation signals of the transmitting electrode arrays 10 have specific phase differences, so that the signals transmitted to the receiving electrode 12 through the coupling capacitors not only have amplitudes modulated by the capacitor values, but also have different phases. The four signals are vectorially superimposed on the receiving electrode 12 through the receiving coupling capacitor C0 to form a resultant signal, the amplitude and phase of which comprehensively reflect the relative displacement information, and the precise detection of the displacement is realized.

[0198] In some embodiments, the capacitive grating displacement sensor 1 further comprises a phase discrimination circuit (not shown in the figure) and a counting circuit (not shown in the figure).

[0199] The phase discrimination circuit is configured to receive the induced signal output by the receiving electrode 12 when the first grid plate 100 and the second grid plate 200 are relatively displaced, and output a direction signal representing the displacement direction by discriminating the phase lead or lag relationship.

[0200] The counting circuit is connected to the output end of the phase discrimination circuit, and is configured as a reversible counter, with the direction signal as the control input of the addition or subtraction counting mode, to count the subdivided displacement pulses; thereby, the phase discrimination circuit and the counting circuit work together to convert the vector information of the relative displacement into precise digital output, so as to realize the displacement direction discrimination and displacement amount accumulation.

[0201] The induced signal output by the receiving electrode 12 is periodic, and one period of the induced signal is completed when the first grid plate 100 and the second grid plate 200 are relatively displaced by a first pitch L1. The period (or pulse) of the induced signal is counted continuously to accumulate the total relative displacement amount.

[0202] The counting circuit counts the period of the induced signal to determine the integer period part of the displacement, and then obtains the fine displacement value within the period by detecting the phase difference of the signal and querying the pre-stored phase-displacement corresponding table or according to the phase-displacement corresponding relationship, and finally fuses the two to output the precise unique position value. That is, the precise value of the relative displacement between the first grid plate 100 and the second grid plate 200 can be obtained through the number of period cycles and the phase difference.

[0203] Please refer to Figure 19 , Figure 19 The structure schematic diagram of an embodiment of the capacitive grating displacement sensor provided by the embodiments of the present application.

[0204] In some embodiments, the capacitive displacement sensor 1 further comprises a flexible circuit board 300 and a printed circuit board 400. The printed circuit board 400 is connected with the first grating plate 100 through the flexible circuit board 300.

[0205] Exemplarily, the phase discrimination circuit and the counting circuit can be integrated in the printed circuit board 400.

[0206] In the above embodiments, the description of each embodiment is focused on, and the part not described in detail in a certain embodiment can be referred to the relevant description of other embodiments.

[0207] The above is only the implementation of the present application, and does not limit the patent protection scope of the present application. Any equivalent structure or equivalent process transformation using the content of the present application specification and drawings, or direct or indirect application in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A capacitive displacement sensor, characterized in that, include: The first grid plate includes a first stage and a plurality of emission electrode arrays, each of the emission electrode arrays including a plurality of emission electrodes arranged in a predetermined direction at a first pitch period. The second grid plate includes a second stage and a reflective electrode; the reflective electrode includes a plurality of reflective electrode strips. The emitting electrode array is adjustablely disposed on the first stage, and / or the reflecting electrode strip is adjustablely disposed on the second stage; The reflective electrode strips corresponding to each of the aforementioned emission electrode arrays constitute a reflective electrode group; the reflective electrode strips at the same position in each of the aforementioned reflective electrode groups are defined as a second reference; In the preset direction, the transmitting electrodes at the same position in each of the transmitting electrode arrays are used as the first reference, and the offsets of each second reference relative to the corresponding first reference are not equal, and the offsets are adjustable.

2. The capacitive displacement sensor according to claim 1, characterized in that, The first grid plate also includes a plurality of first substrates, each of which is equipped with an emission electrode array. The offset is adjusted by adjusting the relative displacement between the first substrate and the first stage along the preset direction. In the preset direction, the width of the emitting electrode is equal to the width of the corresponding reflective electrode strip.

3. The capacitive displacement sensor according to claim 2, characterized in that, The first substrate is slidably connected to the first platform; or, the first substrate is detachably disposed on the first platform to enable replacement of the first substrate.

4. The capacitive displacement sensor according to claim 2, characterized in that, The first stage has a first assembly scale extending along the preset direction, and the mounting position of the first substrate is determined based on the first assembly scale; the line width and line spacing of the first assembly scale are both equal to the width of the emitting electrode.

5. The capacitive displacement sensor according to claim 1, characterized in that, Each of the emitting electrode arrays corresponds to at least one of the reflecting electrode strips; the reflecting electrode strips corresponding to each emitting electrode array constitute a reflecting electrode group; The second grid plate also includes a second substrate, and each second substrate is equipped with a set of the reflective electrodes. The offset is adjusted by adjusting the relative displacement between the second substrate and the second stage along the preset direction. When there are multiple reflective electrode strips in the reflective electrode group, the reflective electrode strips are arranged in a second pitch period, and the second pitch is an integer multiple of the first pitch.

6. The capacitive displacement sensor according to claim 5, characterized in that, The second stage has a second assembly scale extending along the preset direction, and the installation position of the second substrate is determined based on the second assembly scale; the line width and line spacing of the second assembly scale are both equal to the width of the reflective electrode strip.

7. The capacitive displacement sensor according to claim 1, characterized in that, Each of the emitting electrode arrays corresponds to a reflective electrode strip that constitutes a reflective electrode group; the emitting electrode arrays are arranged in a third pitch period; the third pitch is n times the first pitch, where n is an integer; in the preset direction, the center distance between any adjacent reflective electrode groups is greater than n times the first pitch and less than n+1 times the first pitch.

8. The capacitive displacement sensor according to claim 1, characterized in that, Each of the emitting electrode arrays corresponds to a reflective electrode strip that constitutes a reflective electrode group; the reflective electrode group is arranged periodically along the preset direction with a fourth pitch; the fourth pitch is m times the first pitch, where m is an integer; in the preset direction, the center-to-center distance between any two adjacent emitting electrode arrays is greater than m-1 times the first pitch and less than m times the first pitch.

9. The capacitive displacement sensor according to claim 1, characterized in that, In the preset direction, the offsets of each second reference relative to the corresponding first reference form an arithmetic sequence, and the tolerance of the arithmetic sequence is determined by the ratio of the first pitch to the total number of the transmitting electrode array.

10. The capacitive displacement sensor according to claim 1, characterized in that, The phase of the excitation signal of each of the transmitting electrode arrays is uniformly distributed within a preset period.

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