Capacitive encoder and electronic equipment

Abstract

The utility model relates to the field of encoders, and discloses a capacitive encoder and an electronic device. The capacitive encoder comprises a rotating shaft, a flexible printed circuit (FPC) which surrounds the rotating shaft and is arranged at an interval with the rotating shaft, a first detection unit and a second detection unit which are arranged on the FPC, and a processor, the first detection unit and the second detection unit are symmetrically arranged relative to the axis of the rotating shaft; the processor is used for determining the rotation angle of the rotating shaft according to the sum of the first detection unit detection signal and the second detection unit detection signal. The first detection unit and the second detection unit which are symmetrically arranged are used for synchronously carrying out angle detection, and the rotation angle of the rotating shaft is determined through the sum of signals detected by the first detection unit and signals detected by the second detection unit, so that the influence of eccentricity and inclination of the rotating shaft caused by assembly is effectively reduced, and the angle detection precision is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of encoder, especially relates to a capacitive encoder and electronic equipment. BACKGROUND

[0002] Encoder is a kind of sensor for measuring rotation angle or linear displacement, its main function is to convert mechanical movement into electrical signal or digital signal, is used to feedback position, speed or angle information to control system, to realize the accurate control of electronic equipment. Current encoder is divided into multiple types, such as photoelectric encoder, magneto electric encoder etc. Low-end photoelectric encoder precision is low, high-end photoelectric encoder cost is very high, so the cost and precision of photoelectric encoder are difficult to take into account. Electromagnetic encoder is susceptible to external magnetic interference, influence encoder precision. And, no matter what type of encoder, there is eccentric, tilt etc. Situation that shaft is relative to shell, influence angle detection precision. Based on this, the industry needs a kind of encoder structure that takes into account precision and cost. UTILITARIAN CONTENT

[0003] The utility model embodiment is to provide a kind of capacitive encoder and electronic equipment, on the basis of high-precision low-cost capacitive encoder, through the first detection unit and the second detection unit symmetrically arranged angle detection is carried out simultaneously, the sum of first detection unit detection signal and second detection unit detection signal is determined the rotation angle of the shaft, to effectively reduce the eccentricity, tilt of shaft caused by assembly, improve angle detection precision.

[0004] To solve the above technical problems, the embodiment of the utility model provides a kind of capacitive encoder, comprising: shaft, the flexible circuit board FPC around the shaft and with the shaft interval setting, first detection unit and second detection unit being arranged on the flexible circuit board FPC, and processor;The first detection unit and the second detection unit are symmetrically arranged relative to the shaft center of the shaft;The processor is used to determine the rotation angle of the shaft according to the sum of first detection unit detection signal and second detection unit detection signal.

[0005] The embodiment of the utility model also provides a kind of electronic equipment, including the capacitive encoder described above.

[0006] Compared with the prior art, this utility model embodiment sets a first detection unit and a second detection unit on the flexible circuit board (FPC) in the capacitive encoder. The first detection unit and the second detection unit are symmetrically arranged with respect to the axis of the rotating shaft. When the rotating shaft is eccentric or tilted, the eccentricity causes the detection result of the first detection unit to deviate, and it also causes the detection result of the second detection unit to deviate by the same reason. By summing the detection signals of the first detection unit and the second detection unit, the influence of the eccentricity or tilt of the rotating shaft on the detection result can be eliminated to a large extent, thereby improving the accuracy of the detected rotation angle of the rotating shaft.

[0007] Additionally, the first detection unit includes: a first metal sheet disposed on the rotating shaft, and a first emitting electrode plate and a first receiving electrode plate disposed on the flexible circuit board (FPC); the first emitting electrode plate and the first receiving electrode plate are both concentrically opposite to the first metal sheet, and the projection of the first metal sheet toward the flexible circuit board (FPC) overlaps with both the first emitting electrode plate and the first receiving electrode plate; the second detection unit includes: a second metal sheet disposed on the rotating shaft, and a second emitting electrode plate and a second receiving electrode plate disposed on the flexible circuit board (FPC); the second emitting electrode plate and the second receiving electrode plate are both concentrically opposite to the second metal sheet, and the projection of the second metal sheet toward the flexible circuit board (FPC) overlaps with both the second emitting electrode plate and the second receiving electrode plate; when the rotating shaft rotates, the first relative area between the first metal sheet and the first receiving electrode plate changes, and the second relative area between the second metal sheet and the second receiving electrode plate changes.

[0008] In addition, the capacitive encoder also includes: a support member disposed on the rotating shaft; the support member is provided with a groove symmetrical with respect to the axis of the rotating shaft, and the first metal sheet and the second metal sheet are fixed in the groove.

[0009] In addition, the first emitter plate and the second emitter plate are integrally formed.

[0010] In addition, the number of the first receiving electrode plate and the second receiving electrode plate is the same, and there are multiple first receiving electrode plates and multiple second receiving electrode plates. The first receiving electrode plates and the second receiving electrode plates are arranged sequentially in the rotation direction of the rotating shaft.

[0011] In addition, the capacitive encoder also includes: a first grounding unit disposed between the first transmitting electrode plate and the first receiving electrode plate, and a second grounding unit disposed between the second transmitting electrode plate and the second receiving electrode plate.

[0012] In addition, the first grounding unit and the second grounding unit are integrally formed.

[0013] In addition, the capacitive encoder also includes: a housing; the flexible circuit board (FPC) is attached to the inner surface of the housing, and the flexible circuit board (FPC) and the housing have the same degree of curvature.

[0014] In addition, the capacitive encoder also includes: a bearing disposed on the rotating shaft; the bearing is used to support the rotating shaft and constrain the displacement of the rotating shaft in the radial or axial direction. Attached Figure Description

[0015] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0016] Figure 1 This is an exploded view of the capacitive encoder according to an embodiment of this solution;

[0017] Figure 2 This is a schematic diagram of the flexible circuit board in the capacitive encoder according to an embodiment of this solution;

[0018] Figure 3 This is a schematic diagram of the unfolded structure of the flexible circuit board in the capacitive encoder according to an embodiment of this solution;

[0019] Figure 4 This is a schematic diagram of the unfolded structure of the flexible circuit board in the capacitive encoder according to an embodiment of this solution;

[0020] Figure 5 This is a diagram of the capacitor structure composed of the first transmitting plate, the first receiving plate, and the first metal sheet in the capacitive encoder according to the embodiment of this solution;

[0021] Figure 6 This is a schematic diagram of the changes in various capacitor signals detected in the capacitive encoder in this embodiment of the solution;

[0022] Figure 7 This is a schematic diagram of the cross-sectional structure of the rotating shaft in the capacitive encoder under normal conditions according to the embodiment of this solution;

[0023] Figure 8 This is a schematic diagram of the cross-sectional structure of the rotating shaft of the capacitive encoder under abnormal conditions in this embodiment of the solution;

[0024] Figure 9 This is a schematic diagram of the cross-sectional structure of the rotating shaft of the capacitive encoder under normal conditions according to the embodiment of this solution;

[0025] Figure 10This is a cross-sectional structural diagram of the capacitor encoder in the embodiment of this solution when the rotating shaft is eccentric;

[0026] Figure 11 This is a cross-sectional structural diagram of the capacitive encoder under tilted conditions in this embodiment of the solution;

[0027] Figure 12 This is a cross-sectional structural diagram of the capacitor encoder in this embodiment under the condition of shaft eccentricity and tilt.

[0028] Figure 13 This is a partial structural diagram of a capacitive encoder based on an embodiment of this solution;

[0029] Figure 14 This is a cross-sectional structural diagram of a capacitive encoder according to an embodiment of this solution;

[0030] Figure 15 This is a schematic diagram of the overall structure of the capacitive encoder according to an embodiment of this solution. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the various embodiments of this utility model will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been presented in the various embodiments of this utility model to enable readers to better understand this application. However, the technical solutions claimed in this application can be implemented even without these technical details and various changes and modifications based on the following embodiments.

[0032] The division of the following embodiments is for ease of description and should not constitute any limitation on the specific implementation of this utility model. The various embodiments can be combined with or referenced by each other without contradiction.

[0033] The embodiments of this utility model relate to a capacitive encoder, such as... Figure 1 As shown, it includes: a rotating shaft 1, a flexible circuit board (FPC) 3 arranged around and spaced apart from the rotating shaft 1, a first detection unit and a second detection unit disposed on the flexible circuit board (FPC) 3, and a processor; the first detection unit and the second detection unit are symmetrically arranged with respect to the axis of the rotating shaft 1; the processor is used to determine the rotation angle of the rotating shaft 1 based on the sum of the detection signals of the first detection unit and the second detection unit.

[0034] Compared with the prior art, this utility model embodiment sets a first detection unit and a second detection unit on the flexible circuit board (FPC) in the capacitive encoder. The first detection unit and the second detection unit are symmetrically arranged with respect to the axis of the rotating shaft. When the rotating shaft is eccentric or tilted, the eccentricity causes the detection result of the first detection unit to deviate, and it also causes the detection result of the second detection unit to deviate by the same reason. By summing the detection signals of the first detection unit and the second detection unit, the influence of the eccentricity or tilt of the rotating shaft on the detection result can be eliminated to a large extent, thereby improving the accuracy of the detected rotation angle of the rotating shaft.

[0035] The first detection unit and the second detection unit can be a capacitor structure constructed from capacitor plates, or a capacitor structure composed of capacitor plates and a metal dielectric. The following is a detailed structural description using an example where both the first and second detection units are composed of capacitor plates and a metal dielectric:

[0036] like Figures 1-2 As shown, the first detection unit includes: a first metal sheet 21 disposed on the rotating shaft 1, and a first emitting electrode 411 and a first receiving electrode 412 disposed on the flexible circuit board FPC; the first emitting electrode 411 and the first receiving electrode 412 are both concentrically opposite to the first metal sheet 21, and the projection of the first metal sheet 21 toward the flexible circuit board FPC overlaps with the first emitting electrode 411 and the first receiving electrode 412. Similarly, the second detection unit is symmetrical to the first detection unit. The second detection unit includes: a second metal sheet disposed on the rotating shaft, and a second emitting electrode and a second receiving electrode disposed on the flexible circuit board FPC; the second emitting electrode and the second receiving electrode are both concentrically opposite to the second metal sheet, and the projection of the second metal sheet toward the flexible circuit board FPC overlaps with the second emitting electrode and the second receiving electrode. When the rotating shaft rotates, the first relative area between the first metal sheet and the first receiving electrode changes, and the second relative area between the second metal sheet and the second receiving electrode changes.

[0037] The capacitor formed by the first metal plate 21, the first emitting plate 411, and the first receiving plate 412 in the first detection unit can be considered as the sum of the capacitor formed by the first emitting plate 411 and the first metal plate 21, and the capacitor formed by the first metal plate 21 and the first receiving plate 412. Each capacitor is represented by the physical formula for a parallel plate capacitor: C = εS / 4πkd; where ε represents the dielectric constant of the medium, determined by the medium between the plates, such as air or water; and k represents the electrostatic constant, also known as the Coulomb constant, which indicates that the force between two point charges, each with a charge of 1C, separated by a distance of 1m in a vacuum is 8.987551 × 10⁹ N, i.e., k = 8.987551 × 10⁹ N·m. 2 / C; S represents the area (projected area) of the two plates facing each other; d represents the vertical distance between the two plates. Therefore, when the area of ​​the first metal sheet 21 facing each other and the first emitting plate 411 remains constant, the capacitance signal changes according to the area of ​​the first metal sheet 21 facing each other and the first receiving plate 412 facing each other. Since the change in the area of ​​the first metal sheet 21 facing each other and the first receiving plate 412 is related to the rotation angle of the rotating shaft 1, theoretically, the rotation angle of the rotating shaft 1 can be determined from the change in the capacitance signal. The area of ​​the first metal sheet facing each other and the first emitting plate can be greater than a preset threshold to ensure the strength of the capacitance signal generated by the capacitor assembly and improve the sensitivity of angle detection.

[0038] The above analysis is based on the detection process under the condition that the distance between the first metal sheet and the first emitting electrode and the first receiving electrode remains constant. In reality, the rotating shaft may be eccentric or tilted. In the case of eccentricity or tilt, the central axis of the rotating shaft will deviate from the central axis of the cylindrical structure composed of the flexible circuit board, which will cause the distance between the first metal sheet and the first emitting electrode and the first receiving electrode to change during the rotation of the rotating shaft, thereby affecting the detection result of the first detection unit.

[0039] To avoid the impact of shaft eccentricity or tilt on the detection results, a second detection unit is set up symmetrically with the first detection unit. The detection principle of the second detection unit is the same as that of the first detection unit described above. When the shaft is eccentric or tilted, the eccentricity causes a deviation in the detection results of the first detection unit, and it also causes the detection results of the second detection unit to have the same deviation. By summing the detection signals of the first detection unit and the second detection unit, the impact of shaft eccentricity or tilt on the detection results can be largely eliminated, thereby improving the accuracy of the detected shaft rotation angle.

[0040] like Figure 3 As shown, the first emitting electrode plate 411 and the second emitting electrode plate 421 are integrally formed, and the first emitting electrode plate 411 and the second emitting electrode plate 421 together form a ring electrode plate that adheres to the flexible circuit board (FPC). The number of the first receiving electrode plate 412 and the second receiving electrode plate 422 is the same, and there are multiple first receiving electrode plates 412 and second receiving electrode plates 422. The first receiving electrode plates 412 and the second receiving electrode plates 422 are arranged sequentially in the rotation direction of the rotating shaft. Figure 3Taking the structure shown as an example, there are two annular plates Tx formed by the first transmitting plate 411 and the second transmitting plate 421, located on both sides of the first receiving plate 412 and the second receiving plate 422, respectively. These annular plates Tx can be used to isolate external interference signals from the first receiving plates (Rx1, Rx2, Rx3, Rx4) and the second receiving plates (Rx1', Rx2', Rx3', Rx4'). Multiple first and second receiving plates can be of the same size or different sizes, but at least the symmetrically arranged first and second receiving plates must have the same size. The capacitive encoder also includes a first grounding unit 413 disposed between the first transmitting plate 411 and the first receiving plate 412, and a second grounding unit 423 disposed between the second transmitting plate 421 and the second receiving plate 422. The first and second grounding units can be integrally formed. When there are two annular electrodes Tx formed by the first emitting electrode plate 411 and the second emitting electrode plate 421, there are also two integrally formed structures of the first grounding unit and the second grounding unit to isolate the first emitting electrode plate 411 and the second emitting electrode plate 421 from direct coupling between the first receiving electrode plate 421 and the second receiving electrode plate 422. In the axial direction of the rotating shaft 1, the width of the integrally formed structure of the first grounding unit and the second grounding unit is smaller than the width of the annular electrodes Tx formed by the first emitting electrode plate 411 and the second emitting electrode plate 421.

[0041] like Figure 4 As shown, in any state, the projection of the first metal sheet 21 toward the flexible circuit board FPC overlaps with at least two first receiving plates, and the relative area between the first metal sheet 21 and at least one first receiving plate changes as the first metal sheet 21 rotates with the shaft. This is to avoid detection blind spots. Similarly, the projection of the second metal sheet 22 toward the flexible circuit board FPC in the second detection unit overlaps with at least two second receiving plates, and the relative area between the second metal sheet 22 and at least one second receiving plate changes as the second metal sheet 22 rotates with the shaft. By using the change values ​​of the capacitance signals generated by the capacitor components formed by the first metal sheet 21 and the multiple first receiving plates, and the change values ​​of the capacitance signals generated by the capacitor components formed by the second metal sheet 22 and the multiple second receiving plates, the rotation angle of the shaft can be determined by eliminating shaft assembly errors.

[0042] Taking the first detection unit as an example, such as Figure 5The diagram shows a capacitor structure formed by the first emitting plate 411, the first receiving plate 412, and the first metal sheet 21. Electric field lines are emitted from the first emitting plate 411 at both ends, conducted through the first metal sheet 21, and transmitted to the first receiving plate 412. The electric field transmission directions between the second emitting plate, the second receiving plate, and the second metal sheet in the second detection unit are the same, and will not be described further here.

[0043] Taking a capacitive encoder with four first receiving plates and four second receiving plates, where the length of the first metal plate in the rotation direction of the shaft is 1.5 times the length of the first receiving plate in the rotation direction of the shaft, and the length of the second metal plate in the rotation direction of the shaft is 1.5 times the length of the second receiving plate in the rotation direction of the shaft, the detection results of each capacitor structure in the capacitive encoder are explained in detail:

[0044] Assume that the capacitance formed by the first transmitting plate and the first receiving plate Rx1 is C11, the capacitance formed by the first transmitting plate and the first receiving plate Rx2 is C12, the capacitance formed by the first transmitting plate and the first receiving plate Rx3 is C13, the capacitance formed by the first transmitting plate and the first receiving plate Rx4 is C14, the capacitance formed by the second transmitting plate and the second receiving plate Rx1' is C21, the capacitance formed by the second transmitting plate and the second receiving plate Rx2' is C22, the capacitance formed by the second transmitting plate and the second receiving plate Rx3' is C23, and the capacitance formed by the second transmitting plate and the second receiving plate Rx4' is C24. C1 = C11 + C21, C2 = C12 + C22, C3 = C13 + C23, C4 = C14 + C24. The first metal plate 21 and the second metal plate 22 rotate one revolution counterclockwise with the shaft. The calculated values ​​of C1, C2, C3, and C4 are as follows: Figure 6 As shown in the figure, the capacitance trend indicates that the calculated capacitance value significantly reduces the impact of non-standard shaft assembly.

[0045] To more clearly illustrate how error elimination is achieved under different assembly problems of the rotating shaft, the working conditions of the first and second detection units are specifically explained in the cases of shaft eccentricity, shaft tilt, and shaft eccentricity + tilt.

[0046] like Figures 7-8 The figure shown is a schematic diagram of the cross-section of the rotating shaft. Figure 7 This represents the normal distribution of the shaft, flexible circuit board, and first detection unit. All electrodes and metal sheets within these components are concentrically arranged. However, if an assembly problem occurs with the shaft, such as… Figure 8 As shown, the central axis of the rotating shaft is offset compared to the central axis of other structures.

[0047] like Figure 9The diagram shows the structure of the first and second detection units under normal conditions. The first and second detection units are symmetrically distributed relative to the central axis of the rotating shaft. If the rotating shaft becomes eccentric, as shown... Figure 10 As shown, at this time, the distance d1 between the first metal sheet 21 and the first transmitting electrode and the first receiving electrode is greater than the distance d between the first metal sheet 21 and the first transmitting electrode and the first receiving electrode under normal conditions; and the distance d2 between the second metal sheet 22 and the second transmitting electrode and the second receiving electrode is less than the distance d between the second metal sheet 22 and the second transmitting electrode and the second receiving electrode under normal conditions. The capacitance C11 detected by the first detection unit at this time is C11 = εS / 4πkd1, where d1 = d + Δ; Δ is the offset of the rotating shaft relative to the normal condition; the capacitance C21 detected by the second detection unit at this time is C21 = εS / 4πkd2, where d2 = d - Δ; the sum of the detection results of the first detection unit and the second detection unit is C = (εS / 4πkd1) + (εS / 4πkd2), C = (1 / 4πk) * 2d / (d 2 -Δ 2 When the offset Δ is small, the sum of the detection results of the first detection unit and the second detection unit is infinitely close to the capacitance detection result under normal conditions, which greatly reduces the impact of shaft eccentricity on the detection results.

[0048] like Figure 11 The diagram illustrates the structure of the first and second detection units when the shaft is tilted. For the first detection unit, the sub-capacitance signal generated by the upper first emitting plate and first receiving plate decreases due to the increased distance between them and the first metal plate caused by the tilt. However, the sub-capacitance signal generated by the lower first emitting plate and first receiving plate increases due to the decreased distance between them. These two deviations cancel each other out, resulting in a final capacitance signal that closely approximates the normal detection signal of the first detection unit. Similarly, in the symmetrical second detection unit, the deviation of the sub-capacitance signal generated by the upper second emitting plate and second receiving plate cancels out the deviation of the sub-capacitance signal generated by the lower second emitting plate and second receiving plate, resulting in a final capacitance signal that closely approximates the normal detection signal of the second detection unit. This minimizes the impact of shaft tilt on the detection results.

[0049] like Figure 12 The diagram shows the structure of the first detection unit and the second detection unit when the shaft is eccentric and tilted. When eccentricity and tilt occur, the error caused by eccentricity and tilt can be eliminated by combining the error elimination methods for eccentricity and tilt as described above.

[0050] In addition, such as Figure 13 As shown, the capacitive encoder also includes: a bearing 7 disposed on the rotating shaft 1; the bearing 7 is used to support the rotating shaft 1 and constrain the radial or axial displacement of the rotating shaft 1. The capacitive encoder also includes: a support member 6 disposed on the rotating shaft 1; the support member 6 is provided with symmetrically arranged grooves, and the first metal sheet 21 and the second metal sheet 22 are fixed in the grooves. Alternatively, the first metal sheet 21 and the second metal sheet 22 can be directly formed on the surface of the support member 6 by laser direct forming technology (LDS). By using the support member 6 as a carrier for the first metal sheet 21 and the second metal sheet 22, the distance between the first metal sheet 21 and the first receiving electrode plate and the first transmitting electrode plate can be reduced, and the distance between the second metal sheet 22 and the second receiving electrode plate and the second transmitting electrode plate can also be reduced, thereby improving the strength of the capacitive detection signal and improving the sensitivity of the detection structure. In addition, the processing of the first metal sheet 21 and the second metal sheet 22 can avoid the influence of the rotating shaft on the rotating shaft, and avoid the processing of the first metal sheet 21 and the second metal sheet 22 affecting the accuracy of the rotating shaft. The first metal sheet 21 and the second metal sheet 22 are connected by a metal connector, so that the two form an integral structure and can be assembled together, simplifying the assembly process.

[0051] like Figure 14 The diagram shows a cross-sectional view of the capacitive encoder. The bearings 7 are symmetrically arranged relative to the shaft 1, ensuring a more balanced force distribution on the shaft. The capacitive encoder also includes a housing 5; a flexible printed circuit board (FPC) 3 is attached to the inner surface of the housing 5, with the FPC and housing exhibiting the same degree of curvature. A base 8 is located at the bottom of the entire capacitive encoder.

[0052] like Figure 15 The diagram shows the overall appearance and structure of the capacitive encoder. The outer casing 5 is a cylindrical hollow structure, containing a flexible circuit board, a rotating shaft, and other components arranged concentrically. A base 8 is located at the bottom of the outer casing 5 to prevent external dust from entering from the bottom and affecting the rotation of the rotating shaft.

[0053] Another feasible embodiment of this utility model relates to an electronic device, including the capacitive encoder as described above.

[0054] Compared with related technologies, the electronic device provided in this embodiment of the present invention is equipped with the capacitive encoder provided in the aforementioned embodiments. Therefore, it also has the technical effects provided in the aforementioned embodiments, and will not be described in detail here.

[0055] Those skilled in the art will understand that the above embodiments are specific embodiments for implementing the present invention, and in practical applications, various changes can be made to them in form and detail without departing from the spirit and scope of the present invention.

Claims

1. A capacitive encoder, characterized in that, include: A rotating shaft, a flexible circuit board (FPC) surrounding and spaced apart from the rotating shaft, a first detection unit and a second detection unit disposed on the flexible circuit board (FPC), and a processor; The first detection unit and the second detection unit are symmetrically arranged with respect to the axis of rotation of the shaft; The processor is used to determine the rotation angle of the rotating shaft based on the sum of the detection signals from the first detection unit and the second detection unit.

2. The capacitive encoder according to claim 1, characterized in that, The first detection unit includes: a first metal sheet disposed on the rotating shaft, and a first emitting electrode plate and a first receiving electrode plate disposed on the flexible circuit board FPC; the first emitting electrode plate and the first receiving electrode plate are both concentrically disposed opposite to the first metal sheet, and the projection of the first metal sheet toward the flexible circuit board FPC overlaps with the first emitting electrode plate and the first receiving electrode plate. The second detection unit includes: a second metal sheet disposed on the rotating shaft, and a second emitting electrode plate and a second receiving electrode plate disposed on the flexible circuit board FPC; the second emitting electrode plate and the second receiving electrode plate are both concentrically opposite to the second metal sheet, and the projection of the second metal sheet toward the flexible circuit board FPC overlaps with the second emitting electrode plate and the second receiving electrode plate; When the shaft rotates, the first relative area between the first metal sheet and the first receiving electrode changes, and the second relative area between the second metal sheet and the second receiving electrode changes.

3. The capacitive encoder according to claim 2, characterized in that, Also includes: Support components are installed on the rotating shaft; The support member is provided with a groove symmetrical to the axis of the rotating shaft, and the first metal sheet and the second metal sheet are fixed in the groove.

4. The capacitive encoder according to claim 2, characterized in that, The first emitter plate and the second emitter plate are integrally formed.

5. The capacitive encoder according to claim 2, characterized in that, The number of the first receiving electrode plate and the second receiving electrode plate are the same, and there are multiple first receiving electrode plates and multiple second receiving electrode plates. The first receiving electrode plates and the second receiving electrode plates are arranged sequentially in the rotation direction of the rotating shaft.

6. The capacitive encoder according to claim 2, characterized in that, Also includes: A first grounding unit is disposed between the first transmitting electrode and the first receiving electrode, and a second grounding unit is disposed between the second transmitting electrode and the second receiving electrode.

7. The capacitive encoder according to claim 6, characterized in that, The first grounding unit and the second grounding unit are integrally formed.

8. The capacitive encoder according to claim 1, characterized in that, Also includes: shell; The flexible circuit board (FPC) is attached to the inner surface of the housing, and the FPC and the housing have the same degree of curvature.

9. The capacitive encoder according to any one of claims 1 to 8, characterized in that, Also includes: The bearing is mounted on the shaft; The bearing is used to support the shaft and constrain the shaft's displacement in the radial or axial direction.

10. An electronic device, characterized in that, include: The capacitive encoder as described in any one of claims 1 to 9.

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