JP2018084455A - Displacement detector and lens barrel including the same, and imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a displacement detector that is accurate and consumes less power than the prior art, a lens barrel using the same, and an imaging device.SOLUTION: A displacement detector comprises a first electrode part that has a plurality of detection electrode groups, and a second electrode part that has a plurality of second electrodes that have a predetermined periodic pattern and can relatively move with respect to the first electrode part. The plurality of detection electrode groups include a first detection electrode group having a plurality of first detection electrodes, and a second detection electrode group having a plurality of second detection electrodes. In a direction in which the plurality of second electrodes are arranged, the distance between the center of gravity of an area in which at least one of two first detection electrodes adjacent to each other of the plurality of first detection electrodes is provided, and the center of gravity of an area in which at least one of two second detection electrodes adjacent to each other of the plurality of second detection electrodes is provided, satisfies a predetermined condition.SELECTED DRAWING: Figure 8

Description

  The present invention relates to a displacement detection device, a lens barrel including the displacement detection device, and an imaging device such as a video camera or a digital still camera in which the lens barrel can be mounted.

  2. Description of the Related Art Conventionally, a lens described in Patent Document 1 is a lens barrel having a so-called manual focus (MF) function in which rotation of an operation ring is detected by electric means, and a focusing lens is electrically driven according to the rotation. A lens barrel is known.

  In Patent Document 1, the passage of a plurality of slits (notches) provided at predetermined intervals in the circumferential direction of the rotation operation unit is detected by a pair of photo interrupters, and the rotation direction of the rotation operation unit is based on the detection signal. A lens barrel that detects the amount of rotation is disclosed. The lens barrel of Patent Document 1 is manually focused by rotating a screw with a stepping motor according to rotation information (rotation direction and rotation amount) of a rotation operation unit, and following the movement of a nut screwed into the screw. The mode (MF function) is realized.

JP 2012-255899 A

  By the way, in order to realize the MF function, the lens barrel of Patent Document 1 detects the rotation of the rotation operation unit with a non-contact configuration using a pair of photo interrupters. For this reason, the photo interrupter requires a relatively large current consumption. In addition, a displacement detection device used in an imaging device or the like is required not only to have low power consumption but also to be able to detect rotation information (displacement information) of the rotation operation unit with high accuracy.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a highly accurate displacement detection device that consumes less power than before, a lens barrel using the displacement detection device, and an imaging device.

In order to achieve the above-described object, the displacement detection device of the present invention includes:
A first electrode portion having a plurality of detection electrode groups;
A second electrode part having a predetermined periodic pattern and having a plurality of second electrodes movable relative to the first electrode part;
Detecting means for detecting displacement based on a capacitance between the first electrode part and the second electrode part;
The plurality of detection electrode groups have a first detection electrode group having a plurality of first detection electrodes, a phase difference of 180 degrees with respect to the first detection electrode group with respect to the predetermined periodic pattern, and a plurality of second detection electrode groups. Including a second detection electrode group having detection electrodes;
In the direction in which the plurality of second electrodes are arranged, the center of gravity of a region where at least a part of two adjacent first detection electrodes among the plurality of first detection electrodes is provided, and the plurality A distance between the center of gravity of an area where at least a part of two adjacent second detection electrodes among the second detection electrodes is provided is less than 1/5 of the period of the predetermined periodic pattern. is there,
It is characterized by that.

  According to the present invention, it is possible to provide a highly accurate displacement detection apparatus, a lens barrel using the same, and an imaging apparatus that consume less power than conventional ones.

1 is a block diagram of an imaging apparatus in Embodiment 1. FIG. 2 is a configuration diagram of an interchangeable lens in Embodiment 1. FIG. 3 is a detailed view of a movable electrode and a fixed electrode in Example 1. FIG. FIG. 3 is a relationship diagram between a fixed electrode and a movable electrode in Example 1. 4 is a detailed view of a detection electrode group in Example 1. FIG. 2 is an equivalent circuit diagram of a fixed electrode and a movable electrode and a signal processing block diagram in Embodiment 1. FIG. 3 is a graph showing a signal based on capacitance formed by a fixed electrode and a movable electrode in Example 1. It is a related figure when the fixed electrode and movable electrode in Example 1 incline relatively. 3 is a detailed view of a detection electrode group in a comparative example of Example 1. FIG. It is a related figure when the fixed electrode and movable electrode in the comparative example of Example 1 incline relatively. 6 is a graph showing a signal based on capacitance formed by a fixed electrode and a movable electrode in a comparative example of Example 1. FIG. 6 is a relationship diagram between a fixed electrode and a movable electrode in Example 2. FIG. 6 is a relationship diagram between a fixed electrode and a movable electrode in Example 3. It is a related figure of the fixed electrode and movable electrode in Example 4.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Configuration of imaging device)
First, referring to FIG. 1, an image pickup apparatus (an image pickup apparatus body (single-lens reflex camera)) on which a displacement detection apparatus according to each embodiment of the present invention can be mounted, and a lens barrel (interchangeable lens) that can be attached to and detached from the image pickup apparatus body. 1 is a block diagram of the imaging apparatus 100. In Fig. 1, solid lines connecting the blocks indicate electrical connections, and broken lines indicate mechanical connections.

  The imaging apparatus 100 includes a camera 2 (an imaging apparatus main body, a camera main body) that holds an imaging element, and an interchangeable lens 1 (lens barrel) that can be attached to and detached from the camera 2. The interchangeable lens 1 includes an operation angle detector 109 (displacement detection device), which will be described later, and a focus lens 106 (lens unit) that is driven based on the detection result of the displacement by the operation angle detector 109. The camera microcomputer 201 controls each part of the camera 2 as will be described later, and communicates with the interchangeable lens 1 via the contact 202 when the interchangeable lens 1 is mounted.

  A signal output from the two-stage stroke release switch 203 is input to the camera microcomputer 201. If the first-stage stroke switch (SW1) is ON in accordance with the signal input from the release switch 203, the camera microcomputer 201 performs exposure determination by a photometric device (not shown), AF operation described later, etc. Get ready.

  When the camera microcomputer 201 detects that the release switch 203 is operated until the second-stage stroke switch (SW2) is turned on, the camera microcomputer 201 transmits an imaging start command to the imaging unit 204 to perform an actual exposure operation. The imaging unit 204 includes an imaging element such as a CMOS sensor or a CCD sensor, and photoelectrically converts an optical image formed via the interchangeable lens 1 and outputs an image signal.

  The focus detection unit 205 exists in the focus detection area according to the focus detection start command transmitted from the camera microcomputer 201 when the SW 1 of the release switch 203 is turned on when the camera 2 is set to an AF mode described later. Focus detection is performed on an object (subject). As a result of focus detection, the focus detection unit 205 determines movement information (movement direction and movement amount) of the focus lens 106 in the optical axis direction necessary for focusing on the object. The display unit 206 displays a captured image obtained by the imaging unit 204.

  The lens microcomputer 101 controls each part of the interchangeable lens 1 as will be described later, and communicates with the camera 2 via the contact 102. The AF / MF switch 103 is a switch for switching between auto focus and manual focus, and is used by the user to select a focus mode from an AF (auto focus) mode and an MF (manual focus) mode.

  In the AF mode, the camera microcomputer 201 transmits the focus detection result determined by the focus detection unit 205 in response to turning on of SW1 of the release switch 203 to the lens microcomputer 101. Based on the focus detection result, the lens microcomputer 101 activates a focus driving motor 104 that generates a driving force by electric energy. The driving force of the focus driving motor 104 is transmitted to the focus driving mechanism 105. The focus driving mechanism 105 drives the focus lens 106 by a necessary amount of movement in the optical axis direction according to the driving force of the focus driving motor 104.

  As the focus drive motor 104, a stepping motor, an ultrasonic motor, or the like is applicable. As the focus drive mechanism 105, a so-called bar-sleeve supported linear motion mechanism, a so-called rotary cam mechanism based on the cooperation of a cam ring having three cam grooves and three linear grooves provided in a fixed portion, etc. Is applicable.

  The position detection encoder 107 (position detection means) is, for example, an absolute value encoder that outputs information corresponding to the position of the focus lens 106 in the optical axis direction. The position detection encoder 107 has a photo interrupter for determining a reference position, and can detect an absolute position by an integrated value of incremental signals (for example, a stepping motor drive pulse or a repetitive signal such as an MR sensor) with a fine interval. Various configurations are applicable.

  In the AF mode, the lens microcomputer 101 drives and controls the focus drive motor 104 in accordance with the necessary movement amount of the focus lens 106 determined based on the focus detection result of the focus detection unit 205. When the required amount of movement of the focus lens 106 and the actual amount of movement that is the detection result of the position detection encoder 107 become equal to each other, the lens microcomputer 101 stops the focus drive motor 104 and indicates that the focus control has ended. To 201.

  On the other hand, in the MF mode, the user can perform focus control by operating the MF operation ring 108. The operation angle detector 109 is an operation angle detector (displacement detection device) that detects the rotation angle (displacement) of the MF operation ring 108. When the user rotates the MF operation ring 108 while confirming the focus state of the subject on the display unit 206, the lens microcomputer 101 reads the output signal of the operation angle detector 109 and drives the focus drive motor 104 to drive the focus lens 106. Is moved in the optical axis direction.

  By finely detecting the rotation of the MF operation ring 108 with the operation angle detector 109, the user can perform delicate focus control, and the operability in the MF mode is improved. Details of detection by the operation angle detector 109 will be described later.

(Configuration of lens barrel)
Next, the configuration of the interchangeable lens 1 will be described with reference to FIG. FIG. 2 is a configuration diagram of the interchangeable lens 1. FIG. 2A is an external view of the interchangeable lens 1. The MF operation ring 108 that is rotatably supported is disposed at the distal end portion (left side in FIG. 2A) of the interchangeable lens 1. FIG. 2B is a perspective view of the MF operation ring 108. The movable electrode 11 (second electrode portion) is a disk-shaped conductive electrode and is integrally attached to the MF operation ring 108. As shown in FIG. 2B, the movable electrode 11 is configured such that the electrode extending in the radial direction has a repeating pattern with or without a fan-shaped electrode in the circumferential direction. The comb teeth are connected on the outside, and the fan-shaped electrodes are connected to each other.

  FIG. 2C is a view of the MF operation ring 108 in which the movable electrode 11 is integrated and the fixed electrode 13 (first electrode portion) as seen from the optical axis direction. FIG. 2D shows a fixed member including the fixed electrode 13. The movable electrode 11 and the fixed electrode 13 are provided facing each other with a certain gap in the optical axis direction. The fixed electrode 13 is an electrode formed in a fan shape long in the circumferential direction. The MF operation ring 108 can be rotated at a fixed position by a fitting support (not shown). In the movable electrode 11, another metal ring as a conductive electrode is disposed on the MF operation ring 108, and is configured integrally with the MF operation ring 108. The fixed electrode 13 is fixed by an adhesive tape or adhesion using the copper foil pattern of the flexible substrate as an electrode. That is, the movable electrode 11 can move relative to the fixed electrode 13.

  However, the present embodiment is not limited to this, and an electrode pattern (to be described later) may be directly formed on the MF operation ring 108, the inner peripheral wall of the lens barrel, etc. by using techniques such as plating, vapor deposition, and screen printing of a conductive material. Good.

(Configuration of displacement detector)
Next, the detection principle of the operation angle detector 109 that detects the rotation angle of the MF operation ring 108 will be described in detail as Embodiment 1 of the present invention with reference to FIG. In order to facilitate the explanation and understanding, the description proceeds in a planar state in which the arcs and circular shapes of the fixed electrode 13 and the movable electrode 11 are linear. FIG. 3 is a detailed view of the movable electrode 11 and the fixed electrode 13. 3A is a detailed view of the fixed electrode 13, FIG. 3B is a detailed view of the movable electrode 11, and FIG. 3C is a detailed view in which the fixed electrode 13 and the movable electrode 11 are overlapped. . The direction indicated by the arrow B in FIG. 3 is the detection direction (rotation direction).

First, the electrode pattern of the fixed electrode 13 will be described with reference to FIG. However, the length of each electrode in the detection direction will be described later with reference to FIG.
As shown in FIG. 3A, the fixed electrode 13 includes a reference electrode portion 13a (GND electrode), an S1 + detection electrode group 15 (first detection electrode group), and an S1-detection electrode group 16 (second detection electrode). Group). The fixed electrode 13 further includes an S2 + detection electrode group 17 (third detection electrode group) and an S2-detection electrode group 18 (fourth detection electrode group). Each detection electrode group includes a plurality of electrodes.

  The S1 + detection electrode group 15 is formed by connecting the S1 + detection electrode 15a and the S1 + detection electrode 15b, and the S1-detection electrode group 16 is formed by connecting the S1-detection electrode 16a and the S1-detection electrode 16b with a wiring (not shown). The S2 + detection electrode group 17 is formed by connecting the S2 + detection electrode 17a and the S2 + detection electrode 17b, and the S2-detection electrode group 18 is formed by connecting the S2-detection electrode 18a and the S2-detection electrode 18b with a wiring (not shown). In FIG. 3A, the boundaries of the electrodes are drawn adjacent to each other, but are actually insulated from each other with a slight gap.

  FIG. 3B shows the movable electrode 11. The shaded region of the movable electrode 11 is a conductive electrode portion. The repeated pattern electrode 11a has a repeated pattern shape having a role of changing the detection output, and the conductive electrode 11b is an electrode that connects the repeated pattern electrode 11a to conduct.

  FIG. 3C shows the fixed electrode 13 and the movable electrode 11 in an overlapping manner. In FIG.3 (c), the movable electrode 11 is shown with the broken line and the oblique line. In FIG. 3C, the length h indicates a length in which the repeated pattern electrode 11a and the detection electrode groups 15 to 18 overlap each other in the direction orthogonal to the detection direction B, and forms a capacitance as a capacitor. It is.

  FIG. 3D is a diagram of the fixed electrode 13 and the movable electrode 11 viewed from the length h direction. In FIG. 3D, the gap d is an interval as a capacitor. The capacitance is proportional to the area where the opposing electrodes overlap each other and the dielectric constant of the gap, and inversely proportional to the gap d. That is, C = ε · S ÷ d (C: capacitance, ε: dielectric constant, S: area, d: gap).

(Relationship between fixed electrode 13 and movable electrode 11)
Next, the relationship between the fixed electrode 13 and the movable electrode 11 will be described with reference to FIG. FIG. 4 is a relationship diagram between the fixed electrode 13 and the movable electrode 11. On the upper side of FIG. 4, each electrode pattern of the fixed electrode 13 is shown as in FIG. On the lower side of FIG. 4, the repeated pattern electrode 11 a of the movable electrode 11 is indicated by hatching.

  As shown in FIG. 3C, the repeated pattern electrode 11 a forms a capacitor by a region having a length h that overlaps with each of the detection electrode groups 15 to 18. FIG. 4 shows eight characteristic states in the process in which the movable electrode 11 moves from the left side to the right side in the detection direction B in the order of status 0 to 7 and status 0. The movable electrode 11 and the fixed electrode 13 form a capacitor by overlapping as shown in FIG. 3 (c). For ease of understanding, the movable electrode 11 and the fixed electrode 13 will be described with reference to FIG.

  The repetitive pitch of the repetitive pattern electrodes 11a (the period of the plurality of second electrodes is a pitch P, and in this embodiment, the ratio of the presence or absence of electrodes within one pitch (the occupation ratio of the electrodes within one pitch) is halved. In the following description, one of the repeated pattern electrodes 11a indicated by hatching is assumed to have an area of “1.” The amount of movement of the movable electrode 11 between the statuses is 1 / 8P. 0 and status 4 are in a state in which the phases are different from each other by 180 degrees (1 / 2P).

  The reference electrode portion 13a (GND electrode) of the fixed electrode 13 overlaps the repetitive pattern electrode 11a of the movable electrode 11 with a total length of 4P, mainly 2P on the left and right sides. In addition, a part of the reference electrode portion 13a overlaps the repeated pattern electrode 11a in the region of the length 6P between the left and right lengths 2P out of the length 10P.

  That is, the reference electrode portion 13a has a length that is an integral multiple of the pitch P in the detection direction B, and in this embodiment, the left and right lengths 2P × 2 = 4P or the overall length 10P. For this reason, the area of the overlapping region between the reference electrode portion 13a and the electrode portion of the movable electrode 11 (repeated pattern electrode 11a) is always constant. Therefore, if the gap is constant, the capacitance is also constant.

  The electrode length of each of the S1 + detection electrode 15a and the S1 + detection electrode 15b constituting the S1 + detection electrode group 15 is 0.5P, and the center-to-center distance between the electrodes is 1P. The S1-detection electrode 16a and the S1-detection electrode 16b constituting the S1-detection electrode group 16 have an electrode length of 0.5P and a distance between the centers of the electrodes of 2P.

  Further, the S1 + detection electrode group 15 and the S1-detection electrode group 16 have a phase difference of 180 degrees (1 / 2P) in the detection direction B. In other words, the S1 + detection electrode group 15 and the S1-detection electrode group 16 are arranged in the detection direction B so as to be shifted by a half pitch (180 degree phase difference, 1/2 pitch) of the repetition period of the repeated pattern electrode 11a. Yes.

  The area of the overlap region between the S1 + detection electrode group 15 and the repeated pattern electrode 11a is “2” in status 0 (first maximum output state), “0” in status 4 (first minimum output state), and status 7. It returns to the area “2” of status 0. Thereafter, this change is repeated.

  More specifically, in status 0, a plurality of electrodes facing the region where the S1 + detection electrode group 15 is provided in the repeated pattern electrode 11a (the fifth and sixth electrodes from the lower side of the drawing in status 0 in FIG. 4). ) Are a plurality of first counter electrodes. At this time, the centers of the plurality of detection electrodes (15a and 15b) included in the S1 + detection electrode group 15 substantially coincide with the centers of the plurality of first counter electrodes.

  Here, the term “substantially coincidence” can be rephrased as follows. That is, the amount of deviation between the center of each of the plurality of detection electrodes (15a and 15b) included in the S1 + detection electrode group 15 and the center of each of the plurality of first counter electrodes is D3, and the plurality of the plurality of the S1 + detection electrode group 15 includes The width of each detection electrode is W3. At this time, in the maximum output state, the state satisfying 0 ≦ D3 / W3 ≦ 0.20 or 0 ≦ D3 / W3 ≦ 0.15 or 0 ≦ D3 / W3 ≦ 0.10 substantially matches the above-described state. In other words.

  Further, in status 4, the electrode (the fifth electrode from the lower side of the paper in status 4 in FIG. 4) facing the region of the repeated pattern electrode 11a where the first detection electrode group 15 is provided is the second counter electrode. To do. At this time, the center of each of the plurality of detection electrodes (15a and 15b) included in the S1 + detection electrode group 15 is different from the center of the second counter electrode. In other words, in the first minimum output state, each of the plurality of detection electrodes (15a and 15b) included in the S1 + detection electrode group 15 does not face the second counter electrode.

  In addition, the area | region where the detection electrode group is provided means the area | region including the detection electrode provided in the end most among the detection electrodes with which each detection electrode group is provided.

  In other words, the region in which the first detection electrode group is provided is between the two first detection electrodes that are farthest from each other among the plurality of first detection electrodes in the direction in which the plurality of second electrodes are arranged. It is an area. Similarly, the region in which the second detection electrode group is provided refers to a region between two second detection electrodes that are farthest from each other among the plurality of second detection electrodes in the direction in which the plurality of second electrodes are arranged. It is an area.

  That is, the region in which at least a part of the plurality of first detection electrodes is provided is the most mutually of at least a part of the plurality of first detection electrodes in the direction in which the plurality of second electrodes are arranged. This is a region between two first detection electrodes that are separated from each other. The same applies to a region where at least some of the plurality of second detection electrodes are provided.

  On the other hand, the area of the overlapping region between the S1-detection electrode group 16 and the repeated pattern electrode 11a returns to “0” in status 0, “2” in status 4, and returns to “0” in status 0 after status 7. Thereafter, this change is repeated.

  More specifically, in status 0, a plurality of electrodes facing the region where the S1-detecting electrode group 16 is provided in the repeated pattern electrode 11a (in the status 0 in FIG. Electrode) is a plurality of third counter electrodes. At this time, the center of at least one (16a or 16b) of the plurality of detection electrodes included in the S1-detection electrode group 16 is different in position from the center of at least one of the plurality of third counter electrodes. In other words, in the first maximum output state, at least one (16a or 16b) of the plurality of detection electrodes included in the S1-detection electrode group 16 does not face at least one of the plurality of third counter electrodes.

  Further, in status 4, a plurality of electrodes (fourth and sixth electrodes from the bottom of the page in status 4 in FIG. 4) facing the region where the S1-detecting electrode group 16 is provided in the repeated pattern electrode 11a. A plurality of fourth counter electrodes are provided. At this time, the centers of the plurality of detection electrodes (16a and 16b) included in the S1-detection electrode group 16 substantially coincide with the centers of the plurality of fourth counter electrodes.

  Here, the term “substantially coincidence” can be rephrased as follows. That is, the deviation amount between the center of each of the plurality of detection electrodes (16a and 16b) included in the S1-detection electrode group 16 and the center of each of the plurality of second counter electrodes is D4, and the S1-detection electrode group 16 is provided. The width of each of the plurality of detection electrodes is W4. At this time, in the minimum output state, the state satisfying 0 ≦ D4 / W4 ≦ 0.20 or 0 ≦ D4 / W4 ≦ 0.15 or 0 ≦ D4 / W4 ≦ 0.10 substantially matches the above-described state In other words.

  In summary, in the first maximum output state, the area where the S1 + detection electrode group 15 and the movable electrode 11 overlap is the same as the area where the S1− detection electrode group 16 and the movable electrode 11 overlap. Greater than area. In the first minimum output state, the area where the S1 + detection electrode group 15 and the movable electrode 11 overlap is larger than the area where the S1− detection electrode group 16 and the movable electrode 11 overlap. Is also small.

  If the gap is constant, the capacitance changes as the area of the overlapping region changes. As described above, regarding the S1 + detection electrode group 15 and the S1-detection electrode group 16, the area of the overlapping region and the capacitance change in the opposite directions. In the present embodiment, the S1 + detection electrode group 15 and the S1-detection electrode group 16 are a set of displacement detection electrode pairs.

  The electrode length of each of the S2 + detection electrode 17a and the S2 + detection electrode 17b constituting the S2 + detection electrode group 17 is 0.5P, and the center-to-center distance between the electrodes is 2P. The electrode length of each of the S2-detection electrode 18a and the S2-detection electrode 18b constituting the S2-detection electrode group 18 is 0.5P, and the center-to-center distance between the electrodes is 1P. The S2 + detection electrode group 17 and the S2-detection electrode group 18 are a pair of displacement detection electrode pairs having a phase difference of 180 degrees (1/2 P) in the detection direction B.

  As shown in FIG. 4, these two sets of displacement detection electrode pairs have a phase shift of 2P + 1 / 4P in terms of the pitch P in the detection direction B, and the two sets of capacitances are (1/4) of each other. ) Indicates a change shifted by P. That is, the area of the overlapping region between the S2 + detection electrode group 17 and the repeated pattern electrode 11a is “2” in status 2 and “0” in status 6. On the other hand, the area of the overlapping region between the S2-detection electrode group 18 and the repeated pattern electrode 11a is “0” in status 2 and “2” in status 6. As described above, regarding the S2 + detection electrode group 17 and the S2-detection electrode group 18, the area of the overlapping region and the capacitance change in the opposite directions.

(The area center of gravity of each detection electrode group)
Next, the area centroid position (or centroid position) of each detection electrode group will be described with reference to FIG. The area centroid position refers to the centroid position of a region where each detection electrode group is provided when viewed from a predetermined direction. The predetermined direction is a direction orthogonal to the direction in which the plurality of electrodes included in the movable electrode 11 are arranged (the vertical direction in FIG. 3) or the direction orthogonal to the circumferential direction of the MF operation ring 108.

  FIG. 5 shows the area centroid (centroid) position in the detection direction B and each electrode of the S1 + detection electrode group 15 and the S1-detection electrode group 16. The horizontal axis indicates the position in the detection direction B with the center of the S1-detection electrode 16a as the origin. Here, the length h of the S1 + detection electrode 15a and the S1 + detection electrode 15b (the length of the region where the repeated pattern electrode 11a and the capacitor are formed) is equal, and the width in the detection direction B is 0.5P. The center of the S1 + detection electrode 15a is disposed at the position of 0.5P on the horizontal axis, and the center of the S1 + detection electrode 15b is disposed at the position of 1.5P on the horizontal axis.

  Accordingly, the area centroid G1 of the S1 + detection electrode group 15 including the S1 + detection electrode 15a and the S1 + detection electrode 15b is at a position of (0.5P + 1.5P) / 2 = 1P. The length h of the S1-detection electrode 16a and the S1-detection electrode 16b (the length of the region where the repeated pattern electrode 11a and the capacitor are formed) is equal, and the width in the detection direction B is 0.5P. The center of the S1-detection electrode 16a is disposed at the position of the horizontal axis 0P, and the center of the S1-detection electrode 16b is disposed at the position of the horizontal axis 2P.

  Accordingly, the area centroid G1 of the S1-detection electrode group 16 including the S1-detection electrode 16a and the S1-detection electrode 16b is at a position of (0P + 2P) / 2 = 1P. That is, the area centroid positions in the detection direction B of the S1 + detection electrode group 15 and the S1− detection electrode group 16 are both in the area centroid G1 indicated by the alternate long and short dash line. Thus, the effect by arrange | positioning a detection electrode so that the area gravity center position of S1 + detection electrode group 15 and S1-detection electrode group 16 may become the vicinity is mentioned later.

  The description relating to the position of the center of gravity of each detection electrode group can be rephrased as follows. That is, in the direction in which the plurality of second electrodes are arranged, the center of gravity of the region where two adjacent first detection electrodes are provided among the plurality of first detection electrodes is defined as the first center of gravity. Furthermore, the center of gravity of a region where two adjacent second detection electrodes are provided among the plurality of second detection electrodes is defined as the second center of gravity. At this time, the distance between the first center of gravity and the second center of gravity is less than 1/5 of the period of the predetermined periodic pattern of the repeated pattern electrodes 11a (the plurality of second electrodes).

  Two detection electrodes adjacent to each other among the plurality of detection electrodes herein are not expressions that mean two detection electrodes adjacent to each other. A description will be given by taking the plurality of detection electrodes 15a and 15b included in the S1 + detection electrode in FIG. 4 as an example. Like the detection electrodes 15a and 15b, in the arrangement direction of the repeated pattern electrodes 11a, a detection electrode included in the same detection electrode group or another detection electrode and a detection electrode provided next or in front thereof are adjacent to each other. Two matching detection electrodes are used.

  The distance between the first centroid and the second centroid is more preferably less than 1/10 or less than 1/20 of the period of the predetermined periodic pattern of the repeated pattern electrode 11a. In the present embodiment, the distance between the first centroid and the second centroid in each of the above-described conditions is the status 0 (first maximum output state) and the status 4 (first minimum output state) shown in FIG. Meet.

  The description relating to the position of the center of gravity of each detection electrode group can be rephrased as follows. That is, in the direction in which the plurality of second electrodes are arranged, the plurality of first detection electrodes are arranged symmetrically with respect to the first symmetry axis, and the plurality of second detection electrodes have the second symmetry axis. They are arranged symmetrically as the center. The distance between the first symmetry axis and the second symmetry axis is less than 1/5 of the period of the predetermined periodic pattern. More preferably, the distance between the first symmetry axis and the second symmetry axis is less than 1/10 or less than 1/20 of the period of the predetermined periodic pattern of the repeated pattern electrode 11a.

  The description relating to the position of the center of gravity of each detection electrode group can be rephrased as follows. That is, in the direction in which the plurality of second electrodes are arranged, the center of gravity of the region where at least a part of the plurality of first detection electrodes is provided is defined as the first center of gravity, and at least one of the plurality of second detection electrodes. The center of gravity of the area where the part is provided is defined as the second center of gravity. At this time, the first center of gravity and the second center of gravity are provided in a region having the same width as the predetermined second electrode of the plurality of second electrodes or a region having the same width as the predetermined region between the plurality of second electrodes. It has been.

  In more detail using FIG. 4, in the status 0 in FIG. 4, the first centroid and the second centroid are the regions between the plurality of second electrodes (in the status 0 in FIG. (The region between the sixth electrodes) is provided in a region having the same width. Further, in status 4 in FIG. 4, the first center of gravity and the second center of gravity are provided in a region having the same width as a predetermined second electrode (the fifth electrode from the lower side of the paper in status 04 in FIG. 4). .

  The description relating to the position of the center of gravity of each detection electrode group can be further rephrased as follows. That is, in the direction in which the plurality of second electrodes are arranged, the shift amount between the first centroid and the second centroid is D1, and the predetermined second electrode width is W1. At this time, 0 ≦ D1 / W1 ≦ 0.20 or 0 ≦ D1 / W1 ≦ 0.15 or 0 ≦ D1 / W1 ≦ 0.10 is satisfied.

(Capacitor equivalent circuit and signal processor)
Next, an equivalent circuit of the capacitor formed by the fixed electrode 13 and the movable electrode 11 and the signal processing unit in this embodiment will be described with reference to FIG. FIG. 6 is an equivalent circuit diagram of the fixed electrode 13 and the movable electrode 11 and a signal processing block diagram. As shown in FIG. 6, each electrode constituting the fixed electrode 13 forms a capacitor with respect to the movable electrode 11.

Here, the capacitances of the capacitors formed by the reference electrode portion 13a and the detection electrode groups 15 to 18 are C _G , C _{S1 +} , C _S1− , C _{S2 +} , and C _S2− , respectively. When the gap is constant, the capacitances C _{S1 +} , C _S1− , C _{S2 +} , and C _S2− are variable capacitors that change as the movable electrode 11 moves. On the other hand, the electrostatic capacitance C _G is a capacitor of a fixed value that does not change by the movement of the movable electrode 11.

The analog switch array 19 includes analog switches 19b to 19e. In this embodiment, the analog switches 19b to 19e are connected in series to the detection electrode groups 15 to 18, respectively. The arithmetic circuit 21 sets the analog switches 19b to 19e in a short circuit state one by one in a time division manner. The electrostatic capacitance detection circuit 20, and the capacitance _{C G,} capacitance _C S1 ₊ are connected in series to the capacitance _{C G, C S1-, C S2} +, electrostatic obtained by synthesizing the respective _{C S2-} Capacitance (synthetic capacitance) is detected. The combined capacity of two capacitors connected in series is equal to the sum of the reciprocals of the two capacitors.

That is, in the electrostatic capacitance _{C G} and _{C S1 +} composite capacitance _{C G_S1 +, 1 / C G_S1} + = 1 / C G + 1 / C S1 + is established. The capacitance _{C G} and _{C S1-} composite capacitance _{C G_S1-,} the capacitance _{C G} and _{C S2 +} composite capacitance _{C G_S2 +,} also applies to the electrostatic capacitance _{C G} and _{C S2-} composite capacitance _{C G_S2-} . The arithmetic circuit 21 outputs signals S ₁ and S ₂ based on the detection result by the capacitance detection circuit 20. Details of these signals will be described later.

(Output signal based on the capacitance of the capacitor)
Next, an output signal based on the capacitance of the capacitor formed by the fixed electrode 13 and the movable electrode 11 will be described with reference to FIG. FIG. 7 is a graph showing an output signal based on the capacitance formed by the fixed electrode 13 and the movable electrode 11, particularly corresponding to the S1 + detection electrode group 15 and the S1− detection electrode group 16.

In FIG. 7, the horizontal axis represents statuses 0 to 7 and 0 described with reference to FIG. 4, and the vertical axis represents electrostatic capacity (combined capacity, differential signal). In FIG. 7, the S1 + combined capacity 711 corresponds to the combined capacity _{CG_S1 +} , and the S1− combined capacity 712 corresponds to the combined capacity _{CG_S1−} . The S1 + detection electrode group 15 has a phase difference of 180 degrees (1 / 2P) with respect to the S1− detection electrode group 16.

That is, with respect to the S1 + detection electrode group 15 and the S1-detection electrode group 16, the area of the overlapping region and the capacitance change in the opposite directions. For this reason, the output value in status 4 of S1−composite capacity 712 is equal to the output value in status 0 of S1 + composite capacity 711. The S1 differential capacitor 713 indicates a differential output (differential signal) of the displacement detection electrode pair. S1 differential capacitance 713 shows a differential signals _{S 1} of S1 + combined capacitance 711 and S1- combined capacitance 712.

That is, the S1 differential capacitor 713 corresponds to a signal obtained by subtracting the S1−combined capacitor 712 from the S1 + combined capacitor 711. These differential operations are performed by the arithmetic circuit 21 shown in FIG. S2 + detection electrode group 17, S2- similarly combined capacitance _{C G_S1 +} also detecting electrode group 18, calculates the combined capacitance _{C G_S1-} differential signal _{S 2.}

  When the lens microcomputer 101 reads this differential signal from the arithmetic circuit 21 as needed, the rotation of the MF operation ring 108 can be detected more finely, and the operability in the MF mode can be further improved. In the present embodiment, the capacitance information from the plurality of displacement detection electrode pairs and the reference electrode pairs for displacement detection is obtained by differential calculation. For this reason, it is possible to perform more stable displacement detection with respect to the stray capacitance, the regulated capacitance generated between each electrode and between adjacent substances.

(Output change when the fixed electrode 13 is inclined relative to the movable electrode 11)
Next, the output change when the fixed electrode 13 and the movable electrode 11 are relatively inclined around the axis in the length h direction will be described with reference to FIGS. FIG. 8 is a view of the fixed electrode 13 and the movable electrode 11 as seen from the length h direction.

  8A shows a case in which the fixed electrode 13 and the movable electrode 11 are parallel, FIG. 8B shows a case in which the fixed electrode 13 and the movable electrode 11 are inclined about the rotation center O2, and FIG. The case of tilting is shown. The S1 + combined capacitor 711, the S1-combined capacitor 712, and the S1 differential capacitor 713 indicated by the solid lines in FIG. 7 correspond to outputs in the case of the positional relationship of FIG. Further, the S1 + combined capacitor 721, the S1-combined capacitor 722, and the S1 differential capacitor 723 shown by broken lines in FIG. 7 correspond to FIG. 8B. The S1 + combined capacitor 731, the S1− combined capacitor 732, and the S1 differential capacitor 733 shown by the one-dot chain line in FIG. 7 correspond to FIG.

  In FIG. 8, gaps L1 to L4 indicate gaps between the fixed electrode 13 and the movable electrode 11 at each position. The output fluctuation when the fixed electrode 13 and the movable electrode 11 are relatively inclined in the direction orthogonal to the detection direction B is such that the area center of gravity of the S1 + detection electrode group 15 and the area center of gravity of the S1-detection electrode group 16 are in the vicinity. It can be reduced by arranging it. Details of this effect will be described later.

(Relationship between the fixed electrode 13 and the movable electrode 11 in the comparative example)
Next, referring to FIGS. 9 to 11, as a comparative example, the relationship between the fixed electrode 113 and the movable electrode 111 when the area centroid of the S1 + detection electrode group 115 and the area centroid of the S1− detection electrode group 116 are not close to each other. Will be explained. FIG. 9 shows the area centroid (centroid) position in the detection direction B of each electrode of the S1 + detection electrode group 115 and S1− detection electrode group 116 in the comparative example. The horizontal axis indicates the position in the detection direction B with the center of the S1 + detection electrode 115a as the origin.

  Here, the length h of the S1 + detection electrode 115a and the S1 + detection electrode 115b (the length of the region in which the repeated pattern electrode 111a and the capacitor are formed) is equal, and the width in the detection direction B is 0.5P. If the center of the S1 + detection electrode 115a is the origin, the center of the S1 + detection electrode 115b is disposed at the position of the horizontal axis 1P.

  Accordingly, the S1 + detection electrode group area gravity center G3 of the S1 + detection electrode group 115 including the S1 + detection electrode 115a and the S1 + detection electrode 115b is at a position of (0P + 1P) /2=0.5P. The length h of the S1-detection electrode 116a and the S1-detection electrode 116b (the length of the region where the repeated pattern electrode 111a and the capacitor are formed) is equal, and the width in the detection direction B is 0.5P. The center of the S1-detection electrode 116a is disposed at the position of the horizontal axis 1.5P, and the center of the S1-detection electrode 116b is disposed at the position of the horizontal axis 2.5P.

  Therefore, the S1-detection electrode group area center of gravity G4 of the S1-detection electrode group 116 including the S1-detection electrode 116a and the S1-detection electrode 116b is at a position of (1.5P + 2.5P) / 2 = 2P. That is, the position of the S1 + detection electrode group area centroid G3 of the S1 + detection electrode group 115 and the S1-detection electrode group area centroid G4 of the S1-detection electrode group 116 in the detection direction B differ by 1.5P.

(Output change when the fixed electrode 13 in the comparative example is inclined relative to the movable electrode 11)
10 and 11 show the positional relationship and the capacitance output when the fixed electrode 113 and the movable electrode 111 are relatively inclined about the axis in the length h direction in the comparative example. These correspond to FIGS. 8 and 7, respectively. FIG. 10 is a view of the fixed electrode 113 and the movable electrode 111 as viewed from the length h direction. 10A shows a case in which the fixed electrode 113 and the movable electrode 111 are parallel, FIG. 10B shows a case in which the fixed electrode 113 and the movable electrode 111 are relatively tilted around the rotation center O5, and FIG. The case of tilting is shown. The S1 + combined capacitor 811, the S1- combined capacitor 812, and the S1 differential capacitor 813 shown by the solid lines in FIG. 11 correspond to outputs in the case of the positional relationship of FIG.

  Further, the S1 + combined capacitor 821, the S1-combined capacitor 822, and the S1 differential capacitor 823 shown by broken lines in FIG. 11 correspond to FIG. 10B, and the S1 + combined capacitor 831 shown by the one-dot chain line in FIG. , S1−combined capacitor 832 and S1 differential capacitor 833 correspond to FIG.

  In FIG. 10, the arrows indicate the gap between the fixed electrode 113 and the movable electrode 111 at each position. FIG. 10B shows a case where the fixed electrode 113 and the movable electrode 111 are relatively inclined around the rotation center O5. Compared to the parallel case (FIG. 10A), the S1 + detection electrode group 115 has a gap. And the gap of the S1-detecting electrode group 116 is narrowed.

  For this reason, the output of the S1 + combined capacitor 821 is smaller than the output S1 + combined capacitor 811 in parallel because the gap is widened. The output of the S1-combined capacitor 822 is larger than the output S1-combined capacitor 812 when parallel because the gap is narrowed. As a result, the entire output of the S1 differential capacitor 823 is smaller than the output S1 differential capacitor 813 in parallel.

  FIG. 10C shows a case where the fixed electrode 113 and the movable electrode 111 are relatively inclined around the rotation center O6. Compared to the parallel case (FIG. 10A), the S1 + detection electrode group 115 and the S1 -Both the detection electrode groups 116 have wide gaps. The S1 + detection electrode group 115 is disposed at a position away from the rotation center O6, and the S1-detection electrode group 116 is disposed at a position near the rotation center O6.

  Therefore, the gap spread is larger in the S1 + detection electrode group 115 than in the S1− detection electrode group 116. For this reason, both the S1 + combined capacity 831 and the S1- combined capacity 832 have smaller outputs than the parallel output S1 + combined capacity 811 and S1- combined capacity 812, and the variation amount of S1 + combined capacity is S1-combined. It is larger than the fluctuation amount of the capacity. Thus, since the difference in the amount of fluctuation of the combined capacitance between S1 + and S1− is large, the entire output of the S1 differential capacitor 833 is smaller than the output S1 differential capacitor 813 in parallel.

  Thereby, in the electrode arrangement of the comparative example, when the relative inclination occurs between the fixed electrode 113 and the movable electrode 111 due to the mechanical backlash of the MF operation ring 108, the output greatly fluctuates. If the output fluctuates, the rotational displacement of the MF operation ring 108 is erroneously detected. For this reason, the operativity in MF mode falls.

(Principle capable of reducing output fluctuation when the electrode is tilted)
Next, an effect of reducing output fluctuation when the fixed electrode 13 and the movable electrode 11 are relatively inclined in the length h direction in the embodiment will be described. FIG. 8B shows a case in which it is relatively inclined around the rotation center O2.

  In the detection direction B, the rotation center O2 is at the same position as the area centroid G1 of the S1 + detection electrode group 15 and the S1− detection electrode group 16. Therefore, compared to the parallel case (FIG. 8A), in the S1 + detection electrode group 15, the gap of the S1 + first gap L3 is widened, and the gap of the S1 + second gap L4 is narrowed.

  Here, the area centroid G1 is a position where the sum of (distance from the area centroid to the center of each electrode) × (electrode area) becomes equal on the left and right of the area centroid. When the fixed electrode 13 and the movable electrode 11 are relatively inclined, the gap fluctuation amount is proportional to the distance from the rotation center. When the gap fluctuation amount is large, the fluctuation of the capacitance value also increases.

  That is, when the distance from the rotation center is large, the variation in the capacitance value increases. The capacitance value is expressed by C = ε · S ÷ d (C: capacitance, ε: dielectric constant, S: area, d: gap). For this reason, when compared with the same gap fluctuation amount, the fluctuation amount of the capacitance value is proportional to the electrode area.

  In this embodiment, since the areas of the S1 + detection electrode 15a and the S1 + detection electrode 15b are equal, the distances from the area gravity center G1 to the S1 + detection electrode 15a and the S1 + detection electrode 15b are equal. For this reason, the gap fluctuation amount of S1 + first gap L3 and the gap fluctuation amount of S1 + second gap L4 are substantially the same. In addition, since the gap fluctuation directions are opposite in S1 + first gap L3 and S1 + second gap L4, the capacitance output fluctuations of S1 + detection electrode 15a and S1 + detection electrode 15b are in opposite directions.

  Accordingly, since the areas are the same, the gap fluctuation amounts are substantially the same, and the fluctuation directions are opposite, the output fluctuation of the entire S1 + detection electrode group 15 that is the sum of the S1 + detection electrode 15a and the S1 + detection electrode 15b is reduced. This corresponds to the change from the solid line S1 + composite capacity 711 in FIG. 7 to the broken line S1 + composite capacity 721. In this embodiment, the gap fluctuation amounts of S1 + first gap L3 and S1 + second gap L4 are substantially the same.

  However, since the capacitance value is represented by C = ε · S ÷ d, the gap fluctuation amount and the change in the capacitance value are not proportional. That is, the solid line S1 + composite capacity 711 and the broken line S1 + composite capacity 721 do not completely match. For this reason, it is desirable to arrange the S1 + detection electrode group 15 and the S1-detection electrode group 16 in the vicinity. Similarly, in the S1-detection electrode group 16, the output fluctuation is reduced, corresponding to the change from the S1-synthesis capacitor 712 to the S1-synthesis capacitor 722 in FIG.

  Thus, in the present embodiment, the area centroid G1 of the S1 + detection electrode group 15 and the S1-detection electrode group 16 is arranged in the vicinity in the detection direction B, so that when a relative inclination occurs around the rotation center O2, In both cases, an output fluctuation reducing effect can be generated. For this reason, the S1 differential capacitor 723 can also reduce the output fluctuation amount from the S1 differential capacitor 713.

  FIG. 8C shows a case where the tilt is relatively made around the rotation center O3. In the detection direction B, the rotation center O3 is at a position different from the area centroid G1 of the S1 + detection electrode group 15 and the S1− detection electrode group 16. At this time, as compared with the parallel case (FIG. 8A), in the S1 + detection electrode group 15, both the S1 + first gap L3 and the S1 + second gap L4 widen.

  For this reason, the entire output is reduced from S1 + composite capacity 711 to S1 + composite capacity 731 in FIG. Similarly, in the S1-detecting electrode group 16, both the S1-first gap L1 and the S1-second gap L2 widen, and the entire output is reduced from the S1-combined capacitor 712 to the S1-combined capacitor 732 in FIG. .

  Here, the gap d1 indicates the gap between the fixed electrode 13 and the movable electrode 11 when parallel (FIG. 8A), and the gap d2 indicates the fixed electrode 13 and the movable electrode at the position of the center of gravity G1 in FIG. 11 gaps are shown. As described with reference to FIG. 8B, the output fluctuation from the S1 differential capacitor 713 to the S1 differential capacitor 723 with a relative inclination around the area gravity center G1 is small. That is, in FIG. 8C, the output fluctuations of the S1 + detection electrode group 15 and the S1-detection electrode group 16 are close to the output fluctuation when the entire gap is changed from the gap d1 to the gap d2.

  For this reason, the output fluctuation of the S1 + detection electrode group 15 when the relative inclination of the fixed electrode 13 and the movable electrode 11 occurs by arranging the area centroids of the S1 + detection electrode group 15 and the S1-detection electrode group 16 in the vicinity. And the output fluctuation of the S1-detecting electrode group 16 can be made close to each other. As a result, the fluctuation of the differential capacitance (the fluctuation from the S1 differential capacitance 713 to the S1 differential capacitance 733) can be reduced.

(Performance difference between this example and comparative example)
Next, output fluctuations of the example and the comparative example are compared. In the S1 differential capacitor 823 and the S1 differential capacitor 833 with respect to the S1 differential capacitor 813 of FIG. In the S1 differential capacitor 723 and the S1 differential capacitor 733 with respect to the S1 differential capacitor 713 of FIG. 7 of the embodiment, the offset of the entire output is reduced, and the fluctuation of the output amplitude mainly due to the gap fluctuation of the whole remains. Thus, in the embodiment, output fluctuation can be reduced.

  That is, by arranging the area centroids of the S1 + detection electrode group 15 and the S1-detection electrode group 16 in the vicinity in the detection direction B, the relative inclination between the fixed electrode 13 and the movable electrode 11 by the mechanical rattle of the MF operation ring 108 or the like. It is possible to reduce the output fluctuation when this occurs. For this reason, the erroneous detection of the rotational displacement of the MF operation ring 108 due to the output fluctuation can be reduced, and the operability in the MF mode can be further improved.

(Other configurations)
In this embodiment, the area centroid G2 of the S2 + detection electrode group 17 (third detection electrode group) and the S2-detection electrode group 18 (fourth detection electrode group) is arranged in the vicinity in the detection direction B. Thereby, also in the differential capacitance of the S2 + detection electrode group 17 and the S2-detection electrode group 18, the output fluctuation when the relative inclination occurs between the fixed electrode 13 and the movable electrode 11 can be reduced.

  The description regarding the gravity center position of each detection electrode group can be rephrased similarly to the description regarding the gravity center position of the S1 + detection electrode group 15 and the gravity center position of the S1-detection electrode group 16 described above.

  That is, in the direction in which the plurality of second electrodes are arranged, the center of gravity of the region where two adjacent third detection electrodes are provided among the plurality of third detection electrodes is defined as the third center of gravity. Furthermore, the center of gravity of a region where two adjacent fourth detection electrodes are provided among the plurality of fourth detection electrodes is defined as a fourth center of gravity. At this time, the third center of gravity and the fourth center of gravity are provided in a region having the same width as the predetermined second electrode of the plurality of second electrodes or a region having the same width as the predetermined region between the plurality of second electrodes. It has been. At this time, the distance between the third centroid and the fourth centroid is less than 1/5 of the period of the predetermined periodic pattern of the repeated pattern electrodes 11a (the plurality of second electrodes).

  The distance between the third centroid and the fourth centroid is more preferably less than 1/10 or less than 1/20 of the period of the predetermined periodic pattern of the repeated pattern electrode 11a. In the present embodiment, the distance between the third centroid and the fourth centroid in each of the above conditions is the same in both status 2 (second maximum output state) and status 6 (second minimum output state) shown in FIG. Meet.

  Status 2 is a second maximum output state in which the area where the third detection electrode group and the plurality of second electrodes overlap is maximum, and status 6 is the area where the third detection electrode group and the plurality of second electrodes overlap each other. This is the second minimum output state.

  In the above description regarding the provision of the first center of gravity and the second center of gravity in the predetermined second electrode or the predetermined region, the first center of gravity may be replaced with the third center of gravity, and the second center of gravity may be replaced with the fourth center of gravity. . In addition, regarding the conditional expression regarding the deviation amount of both the center of gravity described above, the deviation amount between the third gravity center and the fourth gravity center may be D2, and D1 in the conditional expression may be replaced with D2.

  Further, in the direction in which the plurality of second electrodes are arranged, the plurality of third detection electrodes are arranged symmetrically about the third symmetry axis, and the plurality of fourth detection electrodes are centered on the fourth symmetry axis. Are arranged symmetrically. At this time, the first symmetry axis may be replaced with the third symmetry axis, and the second symmetry axis may be replaced with the fourth symmetry axis.

  In this embodiment, the S1 + detection electrode group 15 and the S2 + detection electrode group 17 have a phase difference of 1 / 4P (90 degrees), and the S1-detection electrode group 16 and the S2-detection electrode group 18 are 1 / 4P. It has a phase difference of (90 degrees). For this reason, the area centroid G1 of the S1 + detection electrode group 15 and the S1-detection electrode group 16 and the area centroid G2 of the S2 + detection electrode group 17 and the S2-detection electrode group 18 are 1 / 4P (90 degrees) in the detection direction B. With a phase difference of. Here, it is desirable to arrange the area centroid G1 and the area centroid G2 as close as possible. As a result, it is possible to reduce the relative deviation between the S1 differential capacitance and the S2 differential capacitance when the relative inclination occurs between the fixed electrode 13 and the movable electrode 11.

  That is, the plurality of detection electrode groups have a phase difference of 180 degrees with respect to the third detection electrode group with respect to the third detection electrode group having a plurality of third detection electrodes and a predetermined periodic pattern, and a plurality of fourth detection electrodes. A fourth detection electrode group having electrodes is further included. The third detection electrode group has a predetermined phase difference with respect to the first detection electrode group with respect to the predetermined periodic pattern, and the fourth detection electrode group has a predetermined phase difference with respect to the second detection electrode group. It has a predetermined phase difference.

  The center of gravity of the region where the two first detection electrodes adjacent to each other among the plurality of first detection electrodes are provided is provided with the two third detection electrodes adjacent to each other among the plurality of third detection electrodes. And having the predetermined phase difference with respect to the center of gravity of the area. The predetermined phase difference here is a phase difference of 90 degrees in this embodiment.

  In the present embodiment, the presence / absence ratio of the electrodes within one pitch of the repetitive pattern electrodes 11a is halved, but the effect of the present embodiment is not impaired even if the ratio is other than this. In addition, although the length of the detection electrode is 0.5P, the effect of this embodiment is not impaired even if the length is other than this.

(Other effects)
In the photo interrupter, the output signal changes between the light shielding portion and the slit portion, and the output of the photo interrupter hardly changes when moved within the width of the light shielding portion or the width of the slit. For this reason, it is difficult to further increase the resolution of the rotation detection because the rotation of the rotation operation unit cannot be detected in a range where neither output of the pair of photo interrupters changes.

  On the other hand, in the operation angle detector 109 in this embodiment, the amplitude of the differential signal output can be increased. If the output amplitude of the differential signal can be increased, the S / N for noise generated at the output increases. For this reason, the resolution of the differential signal read from the arithmetic circuit 17 by the lens microcomputer 101 is increased. As a result, the resolution can be increased as compared with a conventional displacement detection device using a photo interrupter. In the following embodiments of the present invention, the same effects as those of the present embodiment can be obtained.

  Next, Embodiment 2 of the present invention will be described with reference to FIG. The present embodiment is different from the first embodiment in the number and arrangement of a plurality of electrodes constituting the detection electrode group.

  FIG. 12 shows an S1-detection electrode group 216 that is 180 degrees (1 / 2P) in phase with the fixed electrode S1 + detection electrode group 215, and a movable electrode repeating pattern electrode 211a. In the present embodiment, the S1 + detection electrode group 215 and the S1-detection electrode group 216 are each composed of four electrodes.

  The area centroid in this embodiment is in the vicinity of the area centroid G5 in the detection direction B for both the S1 + detection electrode group 215 and the S1-detection electrode group 216. As described in the first embodiment, the area centroid is a position where the sum of (distance from the area centroid to each electrode center) × (electrode area) becomes equal on the left and right of the area centroid.

  This is the same even if the number of electrodes is three or more. Therefore, when the area centroids of the S1 + detection electrode group 215 and the S1-detection electrode group 216 are in the vicinity, a relative inclination between the fixed electrode and the movable electrode around the detection direction B orthogonal direction (up and down direction on the paper surface) occurs. Variations in differential capacitance can be reduced.

  That is, by arranging the area centroids of the S1 + detection electrode group 215 and the S1-detection electrode group 216 in the vicinity in the detection direction B, the relative inclination occurs between the fixed electrode and the movable electrode due to a mechanical rattle of the MF operation ring 108 or the like. If this happens, output fluctuations can be reduced. For this reason, the erroneous detection of the rotational displacement of the MF operation ring 108 due to the output fluctuation can be reduced, and the operability in the MF mode can be further improved.

  Thus, the displacement detection apparatus shown in each embodiment of the present invention has the following configuration. That is, in the direction in which the plurality of second electrodes are arranged, the center of gravity of the region where at least a part of the two first detection electrodes adjacent to each other among the plurality of first detection electrodes is provided is One center of gravity. The center of gravity of an area where at least a part of two adjacent second detection electrodes among the plurality of second detection electrodes is provided is defined as a second center of gravity. At this time, the distance between the first center of gravity and the second center of gravity is less than 1/5 of the period of the predetermined periodic pattern.

  In other words, the displacement detection device shown in each embodiment of the present invention has the following configuration. That is, the center of gravity of a region where two adjacent first detection electrodes are provided among the plurality of first detection electrodes is defined as the first center of gravity. Of the plurality of second detection electrodes provided on the inner side or the outer side of the two first detection electrodes adjacent to each other, two adjacent to the first detection electrodes adjacent to each other and adjacent to each other. The center of gravity of the region where the two second detection electrodes are provided is defined as the second center of gravity. At this time, the distance between the first center of gravity and the second center of gravity is less than 1/5 of the period of the predetermined periodic pattern.

  The above configuration will be described with reference to FIG. The center of gravity of the region where the two first detection electrode pairs A (first and fourth electrodes from the lower side in FIG. 12) adjacent to each other is provided is the first center of gravity. A second detection electrode pair B (second and third electrodes from the lower side in FIG. 12) provided inside the first detection electrode pair A, adjacent to each other and adjacent to the first detection electrode pair A is provided. The center of gravity of the provided area is the second center of gravity.

  This relationship indicates that the first detection electrode pair C (sixth and seventh electrodes from the lower side in FIG. 12) and the second detection electrode pair D (fifth and eighth electrodes from the lower side in FIG. 12) and It also holds in between. Alternatively, this also holds in the configuration including the third detection electrode group and the fourth detection electrode group, and also holds in the relationship of the centroid positions of the regions where the plurality of detection electrode groups using the above-described symmetry axes are provided.

  On the other hand, there are no two second detection electrodes inside the first detection electrode pair E (fourth and sixth electrodes from the lower side in FIG. 12). Further, there are no two second detection electrodes adjacent to the first detection electrode pair E outside the first detection electrode pair E.

  Next, Embodiment 3 of the present invention will be described with reference to FIG. This embodiment is different from Embodiments 1 and 2 in the shape and arrangement of a plurality of electrodes constituting the detection electrode group.

  FIG. 13 shows an S1-detection electrode group 316 that is 180 degrees (1/2 P) in phase with the fixed electrode S1 + detection electrode group 315, and a repetitive pattern electrode 311a that is a movable electrode. In this embodiment, the S1 + detection electrode group 315 and the S1-detection electrode group 316 are each composed of four electrodes. The length of each electrode in the detection direction B is 0.5P, and the length orthogonal to the detection direction B (vertical direction on the paper surface) is 2 (total 4), the length h, and the other 2 (total 4). ) Is the length h / 2.

  The area centroid in this embodiment is in the vicinity of the area centroid G6 in the detection direction B for both the S1 + detection electrode group 315 and the S1-detection electrode group 316. Even when the area of each electrode is different, the area centroid is a position where the sum of (distance from the area centroid to each electrode center) × (electrode area) becomes equal on the left and right of the area centroid. For this reason, even when the area of each electrode is different as in the present embodiment, the effect of reducing the variation in differential capacitance is not impaired.

  That is, when the area center of gravity of the S1 + detection electrode group 315 and the S1-detection electrode group 316 is in the vicinity, a relative inclination between the fixed electrode and the movable electrode around the detection direction B orthogonal direction (up and down direction on the paper surface) occurs. Variations in differential capacitance can be reduced.

  That is, by arranging the area centroids of the S1 + detection electrode group 315 and the S1-detection electrode group 316 in the vicinity in the detection direction B, the relative inclination occurs between the fixed electrode and the movable electrode due to the mechanical backlash of the MF operation ring 108 or the like. If this happens, output fluctuations can be reduced. For this reason, the erroneous detection of the rotational displacement of the MF operation ring 108 due to the output fluctuation can be reduced, and the operability in the MF mode can be further improved.

  Next, Embodiment 4 of the present invention will be described with reference to FIG. In the present embodiment, the shape and arrangement of a plurality of electrodes constituting the detection electrode group are different from those in the first to third embodiments.

  FIG. 14 shows an S1-detection electrode group that is 180 degrees (1 / 2P) in phase with the S1 + detection electrode group of the fixed electrode, and a repetitive pattern electrode 411a of the movable electrode. The S1 + detection electrode group is composed of S1 + detection electrodes 415a to 415d, and the S1-detection electrode group is composed of electrodes in which S1-detection electrodes 416a to 416d are connected by a wiring (not shown). The S1 + detection electrode 415a, the S1-detection electrode 416a, the S1 + detection electrode 415d, and the S1-detection electrode 416d have an electrode width of 1.5P. The S1 + detection electrode 415b, the S1-detection electrode 416b, the S1 + detection electrode 415c, and the S1-detection electrode 416c have an electrode width of 0.5P.

  Assuming that the phase with the largest overlap area between the S1 + detection electrode group and the repeated pattern electrode 411a is the maximum output phase, the state where the repeated pattern electrode 411a is arranged in the shaded area in FIG. 14A is the maximum output phase state. On the other hand, when the phase with the smallest overlap area between the S1 + detection electrode group and the repeated pattern electrode 411a is defined as the minimum output phase, the state in which the repeated pattern electrode 411a is arranged in the blank portion in FIG. It is. In other words, the minimum output phase is in a state where the phase is 180 degrees (1 / 2P) different from FIG.

  FIG. 14B shows only a portion where the detection electrode group of the fixed electrodes and the repeated pattern electrode 411a overlap in the maximum output state. FIG. 14C shows only a portion where the detection electrode group of the fixed electrodes and the repeated pattern electrode 411a overlap in the minimum output state.

  In the present embodiment, in the maximum output state, the area centroid of the portion where the S1 + detection electrodes 415a to 415d and the repeated pattern electrode 411a overlap is arranged in the vicinity of the area centroid G7 in the detection direction B. In the maximum output state, the area centroid of the portion where the S1-detection electrodes 416a to 416d and the repeated pattern electrode 411a overlap is arranged in the vicinity of the area centroid G7 in the detection direction B. By arranging in this way, in the maximum output state, it is possible to reduce the fluctuation of the differential capacitance when the relative inclination of the fixed electrode and the movable electrode around the detection direction B orthogonal direction (up and down direction in the drawing) occurs.

  In addition, in the minimum output state, the area centroid of the portion where the S1 + detection electrodes 415a to 415d and the repeated pattern electrode 411a overlap is arranged in the vicinity of the area centroid G7 in the detection direction B. In the minimum output state, the area centroid of the portion where the S1-detection electrodes 416a to 416d and the repeated pattern electrode 411a overlap is arranged in the vicinity of the area centroid G7 in the detection direction B. By arranging in this way, in the minimum output state, it is possible to reduce the fluctuation of the differential capacitance when the relative inclination between the fixed electrode and the movable electrode around the detection direction B orthogonal direction (the vertical direction on the paper surface) occurs.

  Further, by arranging the area center of gravity of the detection electrode group in the maximum output state and the minimum output state in the vicinity in the detection direction B, the fluctuation of the differential capacitance is reduced even in the intermediate phase between the maximum output state and the minimum output state Effect is obtained.

(Modification)
As mentioned above, although the preferable Example of this invention was described, this invention is not limited to these implementation mobile phones, A various deformation | transformation and change are possible within the range of the summary. For example, in each embodiment, the first electrode portion (fixed electrode 13) is provided on the fixed member, and the second electrode portion (movable electrode 11) is provided on the movable member (MF operation ring 108). However, each embodiment is not limited to this, and the first electrode portion may be provided on the movable member and the second electrode may be provided on the fixed member.

11 Movable electrode (second electrode part)
11a Repeat pattern electrode 13 Fixed electrode (1st electrode part)
13a Reference electrode portion 15 S1 + detection electrode group (first detection electrode group)
15a S1 + detection electrode 15b S1 + detection electrode 16 S1- detection electrode group (second detection electrode group)
16a S1-detection electrode 16b S1-detection electrode 17 S2 + detection electrode group 17a S2 + detection electrode 17b S2 + detection electrode 18 S2-detection electrode group 18a S2-detection electrode 18b S2-detection electrode 21 arithmetic circuit (detection means)
109 Operating angle detector (displacement detector)

Claims (10)

A first electrode portion having a plurality of detection electrode groups;
A second electrode part having a predetermined periodic pattern and having a plurality of second electrodes movable relative to the first electrode part;
Detecting means for detecting displacement based on a capacitance between the first electrode part and the second electrode part;
The plurality of detection electrode groups have a first detection electrode group having a plurality of first detection electrodes, a phase difference of 180 degrees with respect to the first detection electrode group with respect to the predetermined periodic pattern, and a plurality of second detection electrode groups. Including a second detection electrode group having detection electrodes;
In the direction in which the plurality of second electrodes are arranged, the center of gravity of a region where at least a part of two adjacent first detection electrodes among the plurality of first detection electrodes is provided, and the plurality A distance between the center of gravity of an area where at least a part of two adjacent second detection electrodes among the second detection electrodes is provided is less than 1/5 of the period of the predetermined periodic pattern. is there,
A displacement detector characterized by the above. The predetermined periodic pattern of the second electrode portion is a repeating pattern having a predetermined period in a predetermined direction.
The displacement detection device according to claim 1. The first electrode portion further includes a reference electrode portion having a length that is an integral multiple of the predetermined period in the predetermined direction.
The displacement detection apparatus according to claim 2. The plurality of detection electrode groups have a third detection electrode group having a plurality of third detection electrodes, a phase difference of 180 degrees with respect to the third detection electrode group with respect to the predetermined periodic pattern, and a plurality of fourth detection electrode groups. A fourth detection electrode group having detection electrodes;
The third detection electrode group has a predetermined phase difference with respect to the first detection electrode group with respect to the predetermined periodic pattern;
The fourth detection electrode group has the predetermined phase difference with respect to the second detection electrode group with respect to the predetermined periodic pattern;
In the direction in which the plurality of second electrodes are arranged, the center of gravity of an area where two adjacent third detection electrodes among the plurality of third detection electrodes are provided, and the plurality of fourth detection electrodes A distance between the center of gravity of the region where the two fourth detection electrodes adjacent to each other are provided is less than 1/5 of the period of the predetermined periodic pattern.
The displacement detection device according to any one of claims 1 to 3, wherein A state in which the area where the first detection electrode group and the plurality of second electrodes overlap is maximized is defined as a first maximum output state.
When the state where the area where the first detection electrode group and the plurality of second electrodes overlap is minimized is the first minimum output state,
In the first maximum output state and the first minimum output state, the center of gravity of a region where two adjacent first detection electrodes among the plurality of first detection electrodes are provided, and the plurality of second detections The distance between the center of gravity of the region where the two second detection electrodes adjacent to each other among the electrodes are provided is less than 1/5 of the period of the predetermined periodic pattern.
The displacement detection apparatus according to any one of claims 1 to 4, wherein A state where the area where the third detection electrode group and the plurality of second electrodes overlap is maximized as a second maximum output state.
When the state where the area where the third detection electrode group and the plurality of second electrodes overlap is the minimum minimum output state,
In the second maximum output state and the second minimum output state, the center of gravity of an area where two adjacent third detection electrodes among the plurality of third detection electrodes are provided, and the plurality of fourth detections The distance between the center of gravity of the region where the two fourth detection electrodes adjacent to each other among the electrodes are provided is less than 1/5 of the period of the predetermined periodic pattern.
The displacement detection apparatus according to claim 4 or 5, wherein With respect to the predetermined periodic pattern, the center of gravity of the region where the two first detection electrodes adjacent to each other among the plurality of first detection electrodes are provided is the two second adjacent to each other among the plurality of third detection electrodes. 3 having the predetermined phase difference with respect to the center of gravity of the region where the detection electrodes are provided,
The displacement detection device according to any one of claims 4 to 6, wherein The predetermined phase difference is a phase difference of 90 degrees.
The displacement detection apparatus according to any one of claims 4 to 7, The displacement detection device according to any one of claims 1 to 8,
A lens unit that is driven based on a detection result of the displacement by the displacement detector.
A lens barrel characterized by that. The lens barrel according to claim 9,
An image sensor;
A camera body that holds the image sensor,
An imaging apparatus characterized by that.

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