Capacitive grating displacement sensor

Abstract

The application provides a capacitive grating displacement sensor. A first grating plate includes a plurality of transmitting electrode groups, each of which includes a plurality of transmitting electrode arrays arranged along a first direction; each of the transmitting electrode arrays includes a plurality of transmitting electrodes arranged periodically along the first direction; a second grating plate includes a plurality of reflecting electrodes; each of the reflecting electrodes includes a plurality of reflecting electrode strips; one of the transmitting electrode groups and one of the reflecting electrodes form a measurement group; in the measurement group, in the first direction, each of the reflecting electrode strips has a different offset from a same position of a first reference in each of the transmitting electrode arrays. By making the offsets of the reflecting electrode strips in the measurement group from the corresponding first reference different, 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 to achieve higher precision displacement measurement under the same process condition.

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, assembly and other 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] The first grid plate comprises a transmitting electrode group, the transmitting electrode group comprises a plurality of transmitting electrode arrays arranged along a first direction; each transmitting electrode array comprises a plurality of transmitting electrodes arranged periodically along the first direction;

[0006] The second grid plate comprises a reflecting electrode; the reflecting electrode comprises a plurality of reflecting electrode strips;

[0007] One transmitting electrode group and one reflecting electrode form a measurement group;

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

[0009] In some embodiments, the number of transmitting electrode groups is multiple, and / or the number of reflecting electrodes is multiple, so that all transmitting electrode groups and all reflecting electrodes form a plurality of measurement groups with different measurement accuracies;

[0010] The first grid plate further comprises at least one receiving electrode arranged along the first direction; in the direction perpendicular to the surface of the first grid plate, the reflecting electrode and the corresponding receiving electrode are partially overlapped;

[0011] The transmitting electrode group is located on the side of the receiving electrode along the second direction, and the first direction and the second direction are perpendicular.

[0012] In some embodiments, the transmitting electrode group is two, and is located on the same side of the receiving electrode; and the reflecting electrode is one.

[0013] In some embodiments, the transmitting electrode group is two, and is located on the same side of the receiving electrode; and the reflecting electrode is one.

[0014] In some embodiments, the reflecting electrode is two, and the two reflecting electrodes are spaced apart and correspond to the same receiving electrode; or,

[0015] The reflecting electrode is one, and the reflecting electrode sequentially spans a transmitting electrode group, a receiving electrode, and another transmitting electrode group.

[0016] In some embodiments, the transmitting electrode group is one; the receiving electrode is two, and is located on the opposite sides of the transmitting electrode group; and the reflecting electrode is two, and is arranged opposite along the first direction and corresponds to the receiving electrode one by one.

[0017] In some embodiments, in the same measurement group, in the first direction, the width of the transmitting electrode is equal to the width of the reflecting electrode strip, and the plurality of transmitting electrodes in the transmitting electrode array are arranged in a first pitch period.

[0018] Each transmitting electrode array corresponds to at least one reflecting electrode strip; the reflecting electrode strip corresponding to each transmitting electrode array constitutes a reflecting electrode group; when the reflecting electrode group of the same measurement group includes a plurality of reflecting electrode strips, the reflecting electrode strips are arranged in a second pitch period, and the second pitch is an integer multiple of the corresponding first pitch.

[0019] In some embodiments, the transmitting electrode group is multiple, and the capacitive grating displacement sensor further includes a control circuit configured to control each transmitting electrode group to work independently; in each measurement group, define the reflecting electrode strip at the same position in each reflecting electrode group as a second reference, in the first direction, the offset of each second reference relative to the corresponding first reference constitutes a sequence, and define the non-zero term with the smallest absolute value in each sequence as a reference term; the reference terms of each measurement group are different.

[0020] In some embodiments, in the measurement group, the transmitting electrode array is arranged in a third pitch period, the third pitch is n times the corresponding first pitch, and n is an integer, in the first direction, the center distance between any two adjacent reflecting electrode groups is greater than n times the first pitch and less than n+1 times the first pitch; or,

[0021] In the measurement group, the reflective electrode group is arranged periodically along the first direction with a fourth pitch, the fourth pitch being m times the corresponding first pitch, where m is an integer. In the first direction, the center-to-center distance between any adjacent transmitting electrode arrays is greater than m-1 times the first pitch and less than m times the first pitch.

[0022] In some embodiments, in at least one of the measurement groups, in the first direction, the offsets of each of the second references relative to the corresponding first references form an arithmetic sequence, and the tolerance of the arithmetic sequence is determined by the ratio of the corresponding first pitch to the total number of the emitter electrode arrays corresponding to the emitter electrode group.

[0023] In some embodiments, in each of the measurement groups, the phase of the excitation signal of each of the transmitting electrode arrays is uniformly distributed within a preset period.

[0024] The beneficial effects of this application are as follows: Unlike existing technologies, this application provides a capacitive grating displacement sensor, comprising a first grating and a second grating. The first grating includes an emitting electrode group, which includes multiple emitting electrode arrays arranged along a first direction; each emitting electrode array includes multiple emitting electrodes periodically arranged along the first direction. The second grating includes a reflective electrode, which includes multiple reflective electrode strips. A emitting electrode group and a reflective electrode constitute a measurement group. In the measurement group, in the first direction, the emitting electrodes at the same position in each emitting electrode array serve as a first reference, and the offsets of each reflective electrode strip relative to the corresponding first reference are unequal. By making the offsets of each reflective electrode strip in the measurement group unequal relative to the corresponding first reference, the pitch limited by the manufacturing process is dispersed into multiple offsets in the measurement group, 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. Attached Figure Description

[0025] 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.

[0026] Figure 1 This is a schematic diagram of the structure of the first embodiment of the capacitive displacement sensor provided in this application.

[0027] Figure 2 for Figure 1 A schematic diagram showing the relative positions of the emitting electrode array and the reflecting electrode strips;

[0028] Figure 3 Structure diagram of a second embodiment of the capacitive grating displacement sensor provided by the embodiment of the present application;

[0029] Figure 4 Structure diagram of a third embodiment of the capacitive grating displacement sensor provided by the embodiment of the present application;

[0030] Figure 5 Structure diagram of a fourth embodiment of the capacitive grating displacement sensor provided by the embodiment of the present application;

[0031] Figure 6 Structure diagram of a fifth embodiment of the capacitive grating displacement sensor provided by the embodiment of the present application;

[0032] Figure 7 Structure diagram of a first embodiment of the measurement group provided by the embodiment of the present application;

[0033] Figure 8 Structure diagram of a second embodiment of the measurement group provided by the embodiment of the present application;

[0034] Figure 9 Structure diagram of a third embodiment of the measurement group provided by the embodiment of the present application;

[0035] Figure 10 Equivalent circuit diagram between the first grating plate and the second grating plate provided by the embodiment of the present application;

[0036] Figure 11 For Figure 10 Coupling capacitance-displacement corresponding relationship diagram between each transmitting electrode array and the reflecting electrode;

[0037] Figure 12 Structure diagram of a sixth embodiment of the capacitive grating displacement sensor provided by the embodiment of the present application;

[0038] Figure 13 Structure diagram of an embodiment of the second grating plate provided by the embodiment of the present application;

[0039] Figure 14 Structure diagram of a seventh embodiment of the capacitive grating displacement sensor provided by the embodiment of the present application;

[0040] Figure 15 Structure diagram of a first embodiment of the transmitting electrode array, the reflecting electrode strip and the first assembly scale provided by the embodiment of the present application;

[0041] Figure 16 Structure diagram of a second embodiment of the transmitting electrode array, the reflecting electrode strip and the first assembly scale provided by the embodiment of the present application;

[0042] Figure 17Structure diagram of a third embodiment of the transmitting electrode array, the reflecting electrode strip and the first assembly scale provided by the embodiment of the present application;

[0043] Figure 18 Structure diagram of a fourth embodiment of the transmitting electrode array, the reflecting electrode strip and the first assembly scale provided by the embodiment of the present application;

[0044] Figure 19 Structure diagram of an embodiment of the capacitive grating displacement sensor provided by the embodiment of the present application.

[0045] Explanation of reference numerals:

[0046] 1, capacitive grating 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 base; 15, first assembly scale; 200, second grating plate; 210, second carrier; 20, reflecting electrode; 201, second base; 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

[0047] The scheme of the embodiment of the present application will be described in detail below in combination with the drawings of the specification.

[0048] In the following description, specific details are set forth in order to provide a thorough understanding of the present application. The above summary of the application not only includes some but not all embodiments.

[0049] The technical scheme in the embodiments of the present application will be described clearly and completely below in combination with the drawings of the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work belong to the scope of protection of the present application.

[0050] The terms "first", "second", "third", "etc." are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implying a number of the technical features indicated. Therefore, the features defined with "first", "second", "third", etc. can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" 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 position relationship, movement condition, etc. between the components, and if the specific posture (as shown in the drawings) 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.

[0051] Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment can be included in at least one embodiment of the application. The occurrence of the phrase "in an embodiment" in various places in the specification does not necessarily all refer to the same embodiment, nor is it necessarily independent or alternative embodiments to each other. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0052] In the prior art, the capacitive sensor includes a secondary grid and a primary grid which are parallel to each other but not in contact, the secondary grid has an emitter and a receiver, and the primary grid has a reflector and a shield. The relative displacement of the secondary grid and the primary grid changes the coupling capacitance between the emitter and the reflector to achieve the phase shift of the signal between the receiver and the emitter, and the phase-shifted electrical signal is sent out through a data processing circuit to calculate the relative displacement.

[0053] According to the measurement mechanism of the active phase-discrimination capacitive sensor, the phase difference obtained through the phase-discrimination operation is not completely in linear proportion to the displacement change of the grid of the capacitive sensor, but has a deviation of about 0.1%. Therefore, a lower resolution is needed to ensure a certain output accuracy. In addition, the frequency of the driving signal has a strong electrical correlation with the area of the grid in the capacitive sensor. In order to adapt to the impedance matching requirements of the capacitive sensor and the chip, while taking into account low power consumption and having a certain resolution, the driving frequency of the capacitive 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. In order to improve the resolution, the grid pitch of the capacitive sensor needs to be reduced.

[0054] However, due to the limitations of manufacturing, assembly and other technologies, the reduction space of the grating pitch of the capacitive grating sensor is very limited, which makes it difficult for the phase-detecting capacitive grating sensor displacement measurement system to achieve higher resolution displacement measurement.

[0055] 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 present application is shown in Figure 2 The relative position schematic diagram of the transmitting electrode array and the reflecting electrode strip in Figure 1

[0056] In order to solve the above technical problems, the present 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, and 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, with the same position transmitting electrode 11 in each transmitting electrode array 10 as the first reference.

[0057] By making the offset of each reflecting electrode strip 21 in the measurement group relative to the corresponding first reference 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 achieve higher precision displacement measurement under the same process condition.

[0058] The first direction is a straight line vector direction. The first direction is parallel to the measurement direction.

[0059] During the measurement process, the first grating plate 100 and the second grating plate 200 have relative displacement along the measurement direction.

[0060] One of the first grating plate 100 and the second grating plate 200 is a fixed grating, and the other is a moving grating.

[0061] Exemplarily, the first grating plate 100 is a fixed grating, and the second grating plate 200 is a moving grating.

[0062] The first grating plate 100 and the second grating plate 200 are arranged in a spaced manner in the direction perpendicular to the plate surface direction of the first grating plate 100.

[0063] 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. ​

[0064] Exemplarily, all the transmission electrode arrays 10 in the transmission electrode group 101 are arranged along the first direction, and the two ends of the transmission electrode arrays 10 along the first direction are aligned.

[0065] In other embodiments, the transmission electrode arrays 10 in the transmission electrode group 101 are arranged in sequence along the first direction, and at least two adjacent transmission electrode arrays 10 are arranged in a staggered manner along the direction perpendicular to the first direction.

[0066] In the measurement group, each reflection electrode strip 21 crosses the corresponding transmission electrode array 10.

[0067] The transmission electrode array 10 further comprises a connection bridge 13. The connection 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.

[0068] The connection bridge 13 and the transmission electrode 11 are located in different layers to avoid the connection bridge 13 affecting the coupling effect between the transmission electrode 11 and the corresponding reflection electrode 20.

[0069] The transmission electrode group 101 is at least one.

[0070] Exemplarily, as shown in the figure, the transmission electrode group 101 is one. Figure 1

[0071] In some embodiments, the number of transmission electrode groups 101 is multiple, and / or the number of reflection electrodes 20 is multiple, so that all the transmission electrode groups 101 and all the reflection electrodes 20 form multiple measurement groups with different measurement accuracies; the first grid plate 100 further comprises at least one receiving electrode 12 arranged along the first direction; in the direction perpendicular to the plate surface direction of the first grid plate 100, the reflection electrode 20 and the corresponding receiving electrode 12 are partially overlapped; the transmission electrode group 101 is located at the side of the receiving electrode 12 along the second direction, and the first direction and the second direction are arranged perpendicular to each other.

[0072] The design of multiple measurement groups with different measurement accuracies makes the measurement accuracy of the capacitive grating displacement sensor 1 selectable, so that the measurement accuracy can be flexibly selected according to the application requirements, and the performance and efficiency are optimized.

[0073] ​The transmitting electrode 11 is applied with an excitation signal. An electric field is generated around the transmitting electrode 11 and projected onto the corresponding reflecting electrode 20. The reflecting electrode 20 is floating, i.e. the reflecting electrode 20 is not powered. The reflecting electrode 20 is a conductor although it is not powered. According to the principle of electromagnetism, the electric field induces a charge on the floating reflecting electrode 20, which generates a potential. The reflecting electrode 20 with the induced potential itself becomes a field source and emits an electric field. At this time, the receiving electrode 12 induces a current / voltage signal inside it 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 among 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.

[0074] The partial overlapping design of the receiving electrode 12 and the reflecting electrode 20 enhances the capacitive coupling effect.

[0075] Exemplarily, the overlapping area between the reflecting electrode 20 and the corresponding receiving electrode 12 is partially in a block structure, which further enhances the capacitive coupling effect between the receiving electrode 12 and the reflecting electrode 20 and the sensitivity of the capacitive change.

[0076] In the measurement group, the reflecting electrode strip 21 is arranged to extend along the second direction and is arranged to be spaced apart along the first direction.

[0077] 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.

[0078] When there are multiple transmitting electrode groups 101, the multiple transmitting electrode groups 101 work in time division to reduce signal interference.

[0079] 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.

[0080] As Figure 3 shown in the figure, in the first specific embodiment, the transmitting electrode group 101 is two and located on the same side of the receiving electrode 12; the reflecting electrode 20 is one.

[0081] The two transmitting electrode groups 101 and the one reflecting electrode 20 can respectively constitute two measurement groups.

[0082] The two measurement groups share the same receiving electrode 12 and the same reflecting electrode 20 to reduce the number of receiving electrodes 12 and reflecting electrodes 20, thereby saving costs.

[0083] For example, in the first measurement group, each emitting electrode array 10 corresponds to two reflective electrode strips 21, and the two corresponding reflective electrode strips 21 have the same overlap area with their respective emitting electrodes 11, so as to increase the coupling effect between the emitting electrode 11 and the reflective electrode 20. In the second measurement group, each emitting electrode array 10 corresponds to one reflective electrode strip 21, and the offset of each reflective electrode strip 21 relative to the corresponding first reference is not equal.

[0084] The two measurement groups have different measurement accuracies for users to choose from.

[0085] like Figure 4 and Figure 5 As shown, in the second specific embodiment, there are two transmitting electrode groups 101, which are located on opposite sides of the receiving electrode 12 respectively; there are two reflecting electrodes 20, which are spaced apart and correspond to the same receiving electrode 12; or, there is one reflecting electrode 20, which spans one transmitting electrode group 101, the receiving electrode 12 and another transmitting electrode group 101 in sequence.

[0086] There are two emission electrode groups 101, which can form two measurement groups.

[0087] Two transmitting electrode groups 101 are located on opposite sides of the receiving electrode 12 along the second direction, so as to reduce the distance between each transmitting electrode group 101 and the receiving electrode 12, thereby reducing the extension length of the reflecting electrode strip 21 along the second direction, thereby reducing the impedance and enhancing the coupling effect.

[0088] like Figure 4 As shown, in some embodiments, there are two reflective electrodes 20, which are spaced apart and correspond to the same receiving electrode 12, in order to reduce the number of receiving electrodes 12 and save costs; and each transmitting electrode group 101 corresponds to a different reflective electrode 20 to reduce interference.

[0089] like Figure 5 As shown, in some other embodiments, there is one reflective electrode 20, which spans one emitter electrode group 101, the receiver electrode 12 and another emitter electrode group 101 in sequence, so that the two measurement groups share the same receiver electrode 12, which facilitates the preparation of the receiver electrode 12.

[0090] like Figure 6As shown, in the third 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; and the reflecting electrode 20 is two, and is oppositely arranged along the first direction and corresponds to the receiving electrode 12 one by one.

[0091] The transmitting electrode group 101 and the two receiving electrodes 12 can respectively constitute two measurement groups.

[0092] In the first direction, there is an overlapping area between the two reflecting electrode strips 21.

[0093] Exemplarily, in each measurement group, each transmitting electrode array 10 corresponds to one 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 alternately arranged 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 to enhance the coupling effect.

[0094] In other embodiments, in each measurement group, one reflecting electrode strip 21 can correspond to one or more reflecting electrode strips 21.

[0095] In other embodiments, the capacitive grid 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, the transmitting electrode group 101 is 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, and 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.

[0096] 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 reflecting electrode strip 21, and the plurality of transmitting electrodes 11 in the transmitting electrode array 10 are periodically arranged with a first pitch L1; each transmitting electrode array 10 corresponds to at least one reflecting electrode strip 21; the reflecting electrode strip 21 corresponding to each transmitting electrode array 10 constitutes a reflecting electrode group 22; when the reflecting electrode group 22 of the same measurement group includes a plurality of reflecting electrode strips 21, the reflecting electrode strips 21 are periodically arranged with a second pitch L2, and the second pitch L2 is an integer multiple of the corresponding first pitch L1.

[0097] The first pitch L1 is the center distance between the adjacent two 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.

[0098] Exemplarily, in each of the transmitting electrode groups 101, the sizes and shapes of the transmitting electrodes 11 are equal, and the transmitting electrodes 11 in the same transmitting electrode array 10 are arranged at equal intervals.

[0099] In other embodiments, in the transmitting electrode array 10, the intervals between the adjacent transmitting electrodes 11 can not be equal to the width of the transmitting electrodes 11.

[0100] Through the periodic arrangement and directional setting of the reflecting 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.

[0101] The equal-width design of the reflecting electrode strips 21 and the transmitting electrodes 11 helps to maintain the stability of the capacitive coupling.

[0102] When the reflecting electrode group 22 includes a plurality of reflecting electrode strips 21, the multiple relationship of the second pitch L2 relative to the first pitch L1 can realize the 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 reflecting electrode strips 21.

[0103] Exemplarily, the second pitch L2 is greater than the first pitch L1, which can reduce the difficulty of preparation of the reflecting electrode strips 21.

[0104] In some embodiments, the transmitting electrode groups 101 are multiple, and the capacitive grid 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 reflecting electrode strips 21 at the same position in each reflecting electrode group 22 are defined as second references, 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.

[0105] 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.

[0106] The reference term determines the measurement accuracy of the measurement group.

[0107] Exemplarily, as Figure 3As shown, in some embodiments, in the measurement group, the transmission electrode arrays 10 are periodically arranged with a third pitch L3, the third pitch L3 is n times of the first pitch L1, and n is an integer, and in the first direction, the center distance between any two adjacent reflection 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] As shown in FIG. 1, Figures 7 to 9 , Figure 7 FIG. 1 is a structural schematic diagram of a first embodiment of a measurement group provided by an embodiment of the present application, Figure 8 FIG. 2 is a structural schematic diagram of a second embodiment of a measurement group provided by an embodiment of the present application, Figure 9 FIG. 3 is a structural schematic diagram of a third embodiment of a measurement group provided by an embodiment of the present application.

[0109] As shown in FIG. 1, Figure 7 in some embodiments, in the measurement group, the transmission electrode arrays 10 are periodically arranged with a third pitch L3, the third pitch L3 is n times of the first pitch L1, and n is an integer, and in the first direction, the center distance between any two adjacent reflection electrode groups 22 is greater than n times of the first pitch L1 and less than (n+1) times of the first pitch L1.

[0110] The structures of the transmission electrode arrays 10 in the single measurement group are all the same.

[0111] Exemplarily, in the first direction, the center distance between any two adjacent reflection electrode groups 22 is all equal, and is nL+L1 / 4.

[0112] In other embodiments, as shown in FIG. 2, Figure 8As shown, in the first direction, the center distance between any two adjacent reflective electrode groups 22 may not be equal.

[0113] 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.

[0114] 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.

[0115] Each emission electrode array 10 in a single measurement group has the same structure.

[0116] 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.

[0117] 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.

[0118] In other embodiments, the center-to-center spacing between any adjacent emitter electrode arrays 10 may be unequal.

[0119] 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.

[0120] 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.

[0121] The offset can be positive or negative.

[0122] 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 emission electrode array 10.

[0123] 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.

[0124] 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 The coupling capacitance-displacement correspondence relationship between each transmitting electrode array and the reflecting electrode in Figure 10 is shown in the figure.

[0125] 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.

[0126] Exemplarily, the preset period is π.

[0127] 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.

[0128] In other embodiments, the preset period can be other values.

[0129] 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.

[0130] Exemplarily, the number of signal sources is the same as the number of transmitting electrode arrays 10.

[0131] In other embodiments, the excitation signals with specific phase relationships can also be generated through digital signal processing.

[0132] 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.

[0133] 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.

[0134] 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.

[0135] Please refer to Figure 12 , Figure 12 The capacitive grid displacement sensor provided in the sixth embodiment of the present application is shown in the structural schematic diagram.

[0136] The capacitive grid displacement sensor 1 provided in the present application 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 preset direction. The second grid plate 200 comprises a second carrier 210 and a reflection electrode 20, which comprises a reflection electrode strip 21. 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 preset direction, the offset of each reflection electrode strip 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.

[0137] 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.

[0138] 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.

[0139] The preset direction is a straight vector direction. The preset direction is parallel to the measurement direction. The preset direction is the first direction.

[0140] During the measurement process, the first grating plate 100 and the second grating plate 200 have a relative displacement along the measurement direction.

[0141] One of the first grating plate 100 and the second grating plate 200 is a fixed grating, and the other is a moving grating.

[0142] 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.

[0143] 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.

[0144] 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.

[0145] 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.

[0146] 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.

[0147] 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.

[0148] 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.

[0149] The equal-width design of the transmitting electrode 11 and the reflective electrode strip 21 facilitates adjustment of measurement accuracy.

[0150] Exemplarily, the first substrate 14 is rectangular, which facilitates positioning.

[0151] Exemplarily, the first substrate 14 can be provided with positioning marks, which facilitates positioning of the first substrate 14.

[0152] In other embodiments, the first substrate 14 can have other shapes, which are not limited here and can be selected according to actual needs.

[0153] 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.

[0154] 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

[0155] 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.

[0156] 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.

[0157] ​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.

[0158] 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.

[0159] 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.

[0160] Here, the pattern of the first assembly scale 15 is not limited and is selected according to actual needs.

[0161] 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.

[0162] Please refer to Figures 12 to 14 , Figure 13 a structural schematic diagram of a second grid plate provided in an embodiment of the present application, Figure 14 a structural schematic diagram of a seventh embodiment of the capacitive grating displacement sensor provided in an embodiment of the present application.

[0163] In other embodiments, each transmitting electrode array 10 corresponds to at least one reflecting electrode strip 21; the strips of transmitting electrodes 11 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.

[0164] When each reflecting electrode group 22 comprises one reflecting electrode strip 21, in the preset direction, the reflecting electrode strips 21 at the same position in each transmitting electrode array 10 are taken as the first reference, and the offset amounts of the reflecting electrode strips 21 relative to the corresponding first reference are not equal.

[0165] 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.

[0166] The reflective electrode strips 21 of the second substrate 201 are connected to each other.

[0167] 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.

[0168] 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.

[0169] 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.

[0170] The connection between the second substrate 201 and the second carrier 210 can be sliding connection or detachable connection, 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.

[0171] The reflective electrode groups 22 can be arranged periodically or not, which can be selected according to actual needs.

[0172] 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.

[0173] 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.

[0174] 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.

[0175] There are no restrictions on the pattern of the second assembly scale 24 here; it can be selected according to actual needs.

[0176] 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.

[0177] In some embodiments, the emitting electrode array 10 is periodically arranged 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.

[0178] Each emitter electrode array 10 has the same structure, and each emitter electrode group 101 has the same structure.

[0179] 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.

[0180] 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.

[0181] 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.

[0182] In other embodiments, the reflective electrode group 22 is arranged periodically along a preset direction with a fourth pitch L4; the fourth pitch L4 is m times the first pitch L1, where m is an integer; in the preset 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.

[0183] Each emitter electrode array 10 has the same structure, and each emitter electrode group 101 has the same structure.

[0184] For example, such as Figure 17 As shown, each emitting electrode array 101 includes one emitting electrode 11 strips. The center-to-center distance between any two adjacent emitting electrode arrays 10 is equal and is mL1-L1 / 4. Specifically, taking the first emitting electrode 11 in the 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.

[0185] In other embodiments, the center-to-center spacing between the various emitting electrode arrays 10 may be unequal, and no further restrictions are imposed here.

[0186] 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.

[0187] In other embodiments, the emitting electrode arrays 10 may be spaced at unequal intervals, and the reflecting electrode groups 22 may be spaced at unequal intervals.

[0188] In some embodiments, such as Figure 16 As shown, the reflective electrode strips 21 at the same position in each reflective electrode group 22 are defined as the second reference; in a preset 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 first pitch L1 to the total number of the emitting electrode array 10.

[0189] Exemplarily, the first transmitting electrode 11 in the transmitting electrode array 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.

[0190] In other embodiments, as shown in FIG. 6, in the preset direction, the sequence of the offset of each second reference relative to the corresponding first reference can be a non-arithmetic sequence. Figure 18

[0191] 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. 7, the first transmitting electrode 11 in the transmitting electrode array 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 is a non-monotonic sequence. Figure 18

[0192] In some embodiments, as shown in FIG. 8, the phases of the excitation signals of each transmitting electrode array 10 are uniformly distributed in a preset period. Figures 10 to 12

[0193] Exemplarily, the preset period is π.

[0194] The uniform distribution of the phases of the excitation signals 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 each transmitting electrode array 10 form equal-angle intervals on the time axis.

[0195] In other embodiments, the preset period can be other values.

[0196] Exemplarily, a plurality of signal sources are used to generate sine waves or cosine waves with fixed phase differences.

[0197] Exemplarily, the number of signal sources is the same as the number of transmitting electrode arrays 10.

[0198] In other embodiments, the excitation signals with specific phase relationships can also be generated through digital signal processing.

[0199] ​​​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.

[0200] 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).

[0201] 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.

[0202] The counting circuit is connected to the output end of the phase discrimination circuit, and is configured as a reversible counter, taking the direction signal as the control input of the addition or subtraction counting mode, and counting 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.

[0203] The induced signal output by the receiving electrode 12 is periodic, and the induced signal completes one period 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.

[0204] 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.

[0205] Please refer to Figure 19 , Figure 19 The structure schematic diagram of an embodiment of the capacitive grating displacement sensor provided by the present application is shown.

[0206] 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.

[0207] Exemplarily, the phase discrimination circuit and the counting circuit can be integrated in the printed circuit board 400.

[0208] 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.

[0209] 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: A first grid plate includes an emission electrode group, the emission electrode group including a plurality of emission electrode arrays arranged along a first direction; each of the emission electrode arrays includes a plurality of emission electrodes periodically arranged along the first direction; The second grid plate includes a reflective electrode; each of the reflective electrodes includes a plurality of reflective electrode strips; Wherein, one of the emitting electrode groups and one of the reflecting electrodes constitute a measurement group; In the measurement group, in the first direction, the emission electrodes at the same position in each of the emission electrode arrays are used as the first reference, and the offsets of each of the reflection electrode strips relative to the corresponding first reference are not equal; Each of the emitting electrode arrays corresponds to at least one of the reflecting electrode strips; the reflecting electrode strips corresponding to each of the emitting electrode arrays constitute a reflecting electrode group; there are multiple emitting electrode groups, and the capacitive grating displacement sensor further includes a control circuit configured to control each of the emitting electrode groups to work independently; in each measurement group, the reflecting electrode strips at the same position in each of the reflecting electrode groups are defined as a second reference, and in the first direction, the offsets of each second reference relative to the corresponding first reference constitute 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.

2. The capacitive displacement sensor according to claim 1, characterized in that, The number of reflective electrodes is multiple, so that all the emitting electrode groups and all the reflective electrodes constitute multiple measurement groups with different measurement accuracies; The first grid plate further includes at least one receiving electrode extending along the first direction; in a direction perpendicular to the surface of the first grid plate, the reflecting electrode partially overlaps with the corresponding receiving electrode. The transmitting electrode group is located on the side of the receiving electrode along the second direction, and the first direction is perpendicular to the second direction.

3. The capacitive displacement sensor according to claim 1, characterized in that, The first grid plate further includes at least one receiving electrode extending along the first direction; in a direction perpendicular to the surface of the first grid plate, the reflecting electrode partially overlaps with the corresponding receiving electrode. The transmitting electrode group is located on the side of the receiving electrode along the second direction, and the first direction is perpendicular to the second direction; The transmitting electrode group consists of two electrodes, located on the same side of the receiving electrode; the reflecting electrode consists of one electrode.

4. The capacitive displacement sensor according to claim 1, characterized in that, The first grid plate further includes at least one receiving electrode extending along the first direction; in a direction perpendicular to the surface of the first grid plate, the reflecting electrode partially overlaps with the corresponding receiving electrode. The transmitting electrode group is located on the side of the receiving electrode along the second direction, and the first direction is perpendicular to the second direction; The transmitting electrode group consists of two electrodes, which are located on opposite sides of the receiving electrode. Wherein, there are two reflective electrodes, which are spaced apart and correspond to the same receiving electrode; or, The reflective electrode is one, and the reflective electrode sequentially spans one of the transmitting electrode groups, the receiving electrode, and another transmitting electrode group.

5. The capacitive displacement sensor according to claim 1 or 2, characterized in that, In the same measurement group, in the first direction, the width of the emitting electrode is equal to the width of the reflective electrode strip, and the plurality of emitting electrodes in the emitting electrode array are arranged with a first pitch period. When the reflective electrode group of the same measurement group includes multiple reflective electrode strips, the reflective electrode strips are arranged with a second pitch period, and the second pitch is an integer multiple of the corresponding first pitch.

6. The capacitive displacement sensor according to claim 5, characterized in that, In the measurement group, the emitting electrode array is arranged with a third pitch period, where the third pitch is n times the corresponding first pitch, and n is an integer. In the first direction, the center-to-center distance between any two adjacent reflecting electrode groups is greater than n times the first pitch and less than n+1 times the first pitch; or... In the measurement group, the reflective electrode group is arranged periodically along the first direction with a fourth pitch, the fourth pitch being m times the corresponding first pitch, where m is an integer. In the first direction, the center-to-center distance between any adjacent transmitting electrode arrays is greater than m-1 times the first pitch and less than m times the first pitch.

7. The capacitive displacement sensor according to claim 5, characterized in that, In at least one of the measurement groups, in the first direction, the offsets of each of the second references relative to the corresponding first references form an arithmetic sequence, and the tolerance of the arithmetic sequence is determined by the ratio of the corresponding first pitch to the total number of the emission electrode arrays corresponding to the emission electrode group.

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

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