JP2010151986A - Lens position detecting device and lens device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens position detecting device, detecting the absolute position of a lens with high accuracy in a compact constitution, and achieving a wide detection range corresponding to a comparatively large travel, and to provide a lens device to which the above device is applied. <P>SOLUTION: In this lens position detecting device, a cam cylinder (130) is disposed in the interior of a lens-barrel body (112) and the position of a lens (116) configured to move in the optical axis direction in the interior of the cam cylinder (130) is detected. A lens frame (122) is provided with a first sheet coil (171), and a second sheet coil (172) is provided at a position opposite to the first sheet coil (171) of the lens-barrel body (112). With the movement of the lens frame (122), the first sheet coil (171) moves at an opposite distance to the second sheet coil (172), whereby the position of the lens (116) is detected based on an electric signal output from the detection coil according to the moving position. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a lens position detection apparatus and a lens apparatus, and more particularly to a position detection technique suitable for position detection of a movable lens in a lens apparatus having a focus adjustment or a magnification changing mechanism and a lens apparatus to which the position detection technique is applied.

  Conventionally, as a means for detecting a lens position, a method of detecting the rotation speed of an output shaft of a lens driving motor or a power transmission gear is known (Patent Document 1). In this system, a pulse signal is generated by a disc-shaped slit plate attached to a rotating part and a photo interrupter, and the lens position is detected by counting the number of pulses.

  However, this method does not directly detect the position of the lens to be moved, but indirectly grasps the position of the lens from the amount of rotation of the drive mechanism, and there are many gears in the power transmission system. Therefore, it is difficult to detect with high accuracy due to mechanical factors such as backlash.

  As another detection means, a light emitting element and a light receiving element are arranged on the fixed frame portion of the lens barrel, while a diffraction grating is arranged on the moving frame portion to generate a pulse signal and count the number of pulses. It has been proposed (Patent Document 2).

  However, since the method described in Document 2 is optical, it is easily affected by dust and the like and lacks reliability, and the processing accuracy of the diffraction grating greatly affects the detection accuracy, thereby realizing highly accurate detection. It is difficult to manufacture a diffraction grating.

  Furthermore, since the methods described in Patent Documents 1 and 2 both detect the relative position by counting the number of pulses, it is necessary to return to the origin once in order to detect the absolute position. Alternatively, in order to detect the absolute position, a separate mechanism for detecting the absolute position is required, which is disadvantageous for downsizing and cost reduction.

In order to deal with this problem, a method has been proposed in which the lens position is detected from a change in an electrical signal obtained from the planar inductor member by changing the facing distance between the planar inductor member and the conductive member (Patent Document 3).
JP-A-1-217408 JP-A-2-77708 Japanese Patent No. 4129411

  However, in the method described in Patent Document 3, since the signal rapidly decreases as the facing distance between the planar inductor member and the conductive member increases (see paragraph [0017] of FIG. 3 and FIG. 5), the lens position is changed. There is a problem that the detection accuracy becomes worse when the detection range is narrow and the position is far away. To deal with such drawbacks, Patent Document 3 discloses a configuration in which the detection range is extended by using a plurality of planar inductor members, but the number of planar inductor members increases and the configuration of the detection unit becomes complicated. The range that can be expanded is about 2 to 3 times. For example, it is actually difficult to secure a detection range for a movement amount of the order of several tens of millimeters such as a lens device for a television camera.

  In addition to the technique described in Patent Document 3, a mode in which a magnetoresistive element (MR sensor) is used as means for detecting the position of the lens in a non-contact manner is also known. According to the aspect using the MR sensor, it is possible to reduce the influence of friction on the moving object, and to obtain effects such as improved durability.

  FIG. 6 is a schematic diagram illustrating a configuration example of a lens apparatus to which the MR sensor is applied. The detailed structure of the lens apparatus 100 shown in FIG. 1 will be described later. The lens barrel 110 of the lens apparatus 100 is provided with a cam cylinder (inside a barrel main body (fixed cylinder) 112 formed in a cylindrical shape). A rotary lens 130 is rotatably arranged, and a movable lens (group) held by a holding frame 122 is arranged inside the cam cylinder 130. The MR sensor 900 includes a pair of a magnet 902 and a sensor 904 that detects a magnetic change due to relative movement with the magnet 902. In the example shown in FIG. 6, the magnet 902 is disposed on the inner peripheral surface of the cam cylinder 130, and the sensor 904 is disposed on the outer peripheral surface of the holding frame 122.

  However, in the case of the embodiment using the MR sensor, it is necessary to manage the gap (air gap) between the magnet and the sensor, and it is necessary to arrange them close to each other (arranged within a distance of about 100 μm). As in the example shown in FIG. 6, the place where the magnet and the sensor are arranged is limited. Moreover, in order to perform adjustment and confirmation, it is necessary to provide a notch etc. in the outer member of the moving member. In particular, in the three-hanging cam mechanism employed in a broadcasting lens, it is difficult to place the magnet and the sensor close to each other, and the position of the moving member cannot be detected directly, or the detection error increases. There is a problem that it ends up.

  In the conventional apparatus configuration to which the MR sensor is applied as described above, it is difficult to attach the MR sensor as the entire apparatus is downsized.

  The present invention has been made in view of such circumstances, and can detect the absolute position of the lens with high accuracy with a compact configuration, and can realize a wide detection range corresponding to a relatively large amount of movement. It is an object of the present invention to provide a lens position detection device that can be used and a lens device to which the lens position detection device is applied.

  In order to achieve the above-mentioned object, the present invention detects the position of a lens that has an intermediate cylinder arranged inside a fixed cylinder formed in a cylindrical shape and is movable in the optical axis direction inside the intermediate cylinder. A lens position detection device, comprising: a first sheet coil provided in a lens frame that holds the lens; and a second sheet coil provided in a position facing the first sheet coil of the fixed cylinder; One of the first sheet coil and the second sheet coil is an excitation coil, the other is a detection coil, an excitation circuit for supplying an excitation signal to the excitation coil, and the first frame coil as the lens frame moves. When the sheet coil moves in a plane parallel to the second sheet coil while maintaining a facing distance from the second sheet coil, the sheet coil is output from the detection coil according to the movement position. A signal processing circuit for detecting the position of the lens by vapor signal, further comprising a characterized.

  According to the present invention, a planar coil (sheet coil) is used, and the lens position is detected by the resolver principle without changing the distance between the coil surfaces, so that the detection unit can be made thinner and smaller. The absolute position of the lens can be detected with high accuracy. Further, a wide detection range can be dealt with by designing the length of the coil.

  In particular, according to the present invention, since the distance (air gap) between the first sheet coil and the second sheet coil can be increased, the lens position can be directly adjusted even when an intermediate member is disposed between the sheet coils. Detection becomes possible, the degree of freedom in arrangement increases, and the entire apparatus can be downsized.

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

<Principle of detection device>
FIG. 1 is a diagram illustrating a configuration example of a detection unit in a lens position detection device according to an embodiment of the present invention. Here, a linear type resolver 30 using planar sheet coils 10 and 20 will be described as an example. The illustrated resolver 30 includes a pair of a primary side excitation coil 32 and a secondary side detection coil 36. The primary side excitation coil 32 has a first excitation coil pattern 32A for inputting a first excitation signal (sin wave) and a second excitation coil pattern 32B for inputting a second excitation signal (cos wave). Both are insulated from each other.

  As shown in FIG. 1, each of the first excitation coil pattern 32A and the second excitation coil pattern 32B is composed of a rectangular zigzag conductor pattern, and the turn-back pitches of the two coil patterns are the same. They are arranged in a spatial positional relationship with different 90 ° phases.

  The secondary detection coil 36 disposed opposite to the excitation coil 32 is a rectangular meander-shaped conductor similar to the primary excitation coil pattern 32A (or the second excitation coil pattern 32B). It consists of a pattern, and the folding pitch is equivalent to the excitation coil patterns 32A and 32B.

  By applying an excitation signal to the excitation coil 32, a positive and negative magnetic field reflecting the folding pitch in the vertical direction of the coil surface is generated, and an output signal is obtained from the detection coil 36 in accordance with a change in magnetic flux interlinking with the detection coil 36. It is done.

  The detection coil 36 and the exciting coil 32 are arranged to face each other with a certain facing distance d, and both move relative to each other in the surface direction (straight direction indicated by the arrow H in FIG. 1) while maintaining the facing distance d. Thus, the phase of the detection signal on the secondary side changes according to the displacement amount (θ in the figure) corresponding to the positional relationship.

  When the excitation wave V1 = A · sin (ωt) is input to the first excitation coil pattern 32A and the excitation wave V2 = A · cos (ωt) is input to the second excitation coil pattern 32B, two are induced in the detection coil 36. As the secondary side signal E, a signal of E = a · sin (ωt ± θ) is obtained according to the rotation angle corresponding to the displacement amount θ.

  In this example, a modulation signal (a high-frequency excitation signal having V1 as an envelope) V1 ′ = amplitude modulation of the high-frequency signal by the excitation signal (V1) and reversing the polarity of the high-frequency signal at the polarity inversion position of the excitation signal. Asin (ωt) × sin (n · ωt) is input to the first exciting coil pattern 32A. The second excitation coil pattern 32B has a modulation signal (V2 as an envelope) obtained by amplitude-modulating the high-frequency signal with the excitation signal (V2) and inverting the polarity of the high-frequency signal at the polarity inversion position of the excitation signal. High-frequency excitation signal) A high-frequency excitation signal V2 ′ = Acos (ωt) × sin (n · ωt) is input.

  By demodulating the voltage signal induced in the detection coil 36, a phase difference corresponding to the displacement θ of the detection coil 36 with respect to the excitation coil 32 can be obtained.

  The principle and circuit configuration of the two-phase excitation and one-phase detection method using the high-frequency excitation modulated in this way are described in the specification of Japanese Patent No. 3047231.

  Note that a one-phase excitation and two-phase detection method is also possible based on the resolver principle (see, for example, Japanese Patent Laid-Open No. Hei 8-290206), and the roles of the coils arranged opposite to each other can be changed when implementing the present invention. It is.

<Application example to lens device>
FIG. 2 is a configuration diagram illustrating a configuration example of the lens device. FIG. 3 is a cross-sectional view of the lens device shown in FIG. 2 as viewed from the optical axis direction.

  As shown in FIGS. 2 and 3, a cam barrel (rotating barrel) 130 is rotatable inside a barrel main body (fixed barrel) 112 formed in a cylindrical shape in the lens barrel 110 of the lens apparatus 100. The movable lens (group) 116 held by the holding frame (lens frame) 122 is arranged inside the cam cylinder 130. The movable lens 116 is a lens that can move in the optical axis direction, and corresponds to, for example, a zoom (magnification) lens (group), a focus lens (group), a master lens (group), and the like.

  A straight rectilinear groove 140 in the optical axis direction is formed on the peripheral surface of the lens barrel body 112, and a cam groove 136 is formed in the cam barrel 130. In addition, three engagement pins (cam pins) 134 project from the outer peripheral portion of the holding frame 122 of the movable lens 116 at equal intervals along the circumferential direction (two in FIG. 2 are not shown). . These engaging pins 134 are inserted into the cam grooves 136 of the cam barrel 130 and engaged with the rectilinear grooves 140 of the lens barrel body 112. As a result, the holding frame 122 moves back and forth in the optical axis direction in a state where the rotation is restricted, and the holding pin 134 is held at a position where the engaging pin 134 is engaged with the cam groove 136. When the cam barrel 130 rotates, the intersection position of the cam groove 136 of the cam barrel 130 and the rectilinear groove 140 of the lens barrel body 112 changes to a position corresponding to the cam shape, and the engagement pin 134 moves to the intersection position. As a result, the holding frame 122 moves back and forth in the optical axis direction.

  On the other hand, an operation ring 150 is rotatably disposed on the outer peripheral portion of the lens barrel body 112, and a rod-shaped connecting shaft 142 is attached radially inward of the inner peripheral surface of the operation ring 150. The connecting shaft 142 is connected to the cam barrel 130 through a slit (long hole) 144 formed in the lens barrel body 112 in the circumferential direction. As a result, when the operation ring 150 is rotated, the cam cylinder 130 is rotated in conjunction therewith. When the cam cylinder 130 rotates, the holding frame 122 moves back and forth in the optical axis direction as described above. Note that the rotation range of the operation ring 150 is restricted according to the length of the slit 144 in the circumferential direction, thereby determining the movable range of the holding frame 122.

  A configuration example in which the resolver 30 described with reference to FIG. 1 is applied to the lens device 100 configured as described above as means for detecting the movement position of the movable lens 116 in the optical axis direction will be described.

  FIG. 4 is a schematic diagram illustrating a configuration example of the lens device 100 to which the resolver 30 is applied. 4, elements that are the same as or similar to those shown in FIGS. 2 and 3 are given the same reference numerals, and descriptions thereof are omitted.

  In the configuration shown in FIG. 4, a first sheet coil 171 (for example, corresponding to reference numeral 10 in FIG. 1) that constitutes a linear (linear motion) type resolver 30 is arranged on the outer peripheral surface that is the peripheral surface portion of the holding frame 122. The 2nd sheet coil 172 (equivalent to the code | symbol 20 of FIG. 1) is arrange | positioned by the outer peripheral surface which is provided and is the surrounding surface part of the lens barrel main body 112 facing this. Although illustration is omitted, each sheet coil 171, 172 is connected to a wiring member for obtaining electrical connection.

  The second sheet coil 172 is arranged so as to extend linearly in parallel with the optical axis direction over a range in which the holding frame 122 can move. In this example, the second sheet coil 172 is disposed on the outer peripheral surface of the lens barrel main body 112, but is not limited thereto, and may be disposed on the inner peripheral surface of the lens barrel main body 112.

  It should be noted that either of the sheet coils can be configured as an excitation side (primary side) and a detection side (secondary side). However, in the example of FIG. 1, the excitation side is a two-phase excitation winding. In view of this, it is preferable to attach the detection side (secondary side) sheet coil to the moving holding frame 122.

  In the configuration shown in FIG. 4, the holding frame 122 is configured to be movable back and forth in the optical axis direction by rotating the cam cylinder 130 around the optical axis. As the holding frame 122 moves, the first sheet coil 171 moves in a plane parallel to the second sheet coil 172, so that the detection coil (in this example, the first sheet coil 171) is moved according to the position. ) To detect the position of the movable lens 116.

  According to the configuration shown in FIG. 4, since the distance (air gap) between the first sheet coil 171 and the second sheet coil 172 can be increased, the cam cylinder 130 is representative between these sheet coils 171 and 172. Even when the intermediate member is arranged, the lens position can be directly detected, the degree of freedom of arrangement is increased, and the entire apparatus can be downsized.

  Particularly, in the case of a zoom focus lens in which the focus lens operates in conjunction with the zoom lens, the focus accuracy is improved by increasing the position detection of the zoom lens.

<Block diagram of lens device>
FIG. 5 is a block diagram illustrating an example of a circuit configuration of the lens apparatus 100.

  The two-phase exciting coils 202 and 204 in the figure correspond to the symbols 32A and 32B described in FIG. Further, the detection coil 206 in FIG. 5 corresponds to the reference numeral 36 described in FIG. 1 and is attached to the holding frame 122 of the movable lens 116 described in FIG.

  As shown in FIG. 5, excitation signals are input from excitation circuits 212 and 214 to the two-phase excitation coils 202 and 204, respectively. Although the detailed configuration of the excitation circuits 212 and 214 is not illustrated, for example, as disclosed in Japanese Patent No. 3047231, an oscillation circuit, a counter pulse circuit, a high frequency signal generation circuit, an excitation signal generation circuit, a polarity inversion circuit, a modulation It includes a circuit and the like.

  The detection circuit unit 220 on which the excitation circuits 212 and 214 are mounted includes a signal processing circuit 230 that processes an electrical signal output from the detection coil 206. Although the detailed configuration of the signal processing circuit 230 is not illustrated, the signal processing circuit 230 demodulates the modulation signal to obtain a detection signal, and the relative relationship between the detection coil 206 and the excitation coils 202 and 204 from the demodulated detection signal. It includes a position calculation circuit that detects position (displacement amount, rotation angle) and outputs lens position information.

  The position information obtained by the signal processing circuit 230 is notified to the lens position control circuit 240, and the lens position control circuit 240 grasps the current position (absolute position) of the lens from this position information.

  The lens position control circuit 240 controls the drive circuit 242 to move a movable lens (for example, a focus lens or a zoom lens) by driving the motor 244.

  The lens position control circuit 240 can automatically control the motor 244 based on the position information acquired from the signal processing circuit 230, and can perform autofocus control and autozoom control. Further, the lens position control circuit 240 can display lens position information on a display unit (not shown).

<About other advantages of the present embodiment>
The embodiment described above has the following advantages.

  [1] Conventional position detectors such as a potentiometer and a photo interrupter are not required, and space can be saved.

  [2] The absolute position of the lens can be detected.

  [3] Because of the detection using magnetism, noise due to dust and the like is less and the reliability is higher than in the optical type.

  [4] Since the facing distance between the coils is unchanged, the detection signal is stable, and high-precision detection is possible.

  [5] Both forms of detecting the position (displacement) in the straight direction and detecting the position (angle) in the rotational direction can be designed, and the detection range can be easily expanded by designing the coil length.

  [6] Miniaturization is possible by forming a coil print pattern, and miniaturization, high resolution, and low cost are possible.

  [7] Since a high-frequency current due to the modulation signal flows through the excitation coil and the detection coil, a sufficient detection signal can be obtained even with a planar sheet coil (a coil having a small number of turns).

  [8] The detection signal varies little with respect to the temperature change, and stable detection is possible.

  [9] By making the detection circuit an IC, the circuit can be reduced in size.

<Other modification 1>
In FIG. 4, the configuration in which the cam barrel (rotating barrel) 130 is disposed inside the lens barrel body (fixed barrel) 112 is illustrated. However, when the present invention is implemented, the structure of the lens apparatus is the example shown in FIG. It is not limited to. For example, instead of the cam barrel 130 (or inside or outside the cam barrel 130), a cylindrical member configured to be unrotatable with respect to the barrel main body 112 may be disposed.

<Other modification 2>
The form of the planar coil pattern is not limited to the meander shape, and may be a spiral shape.

<Appendix>
As can be understood from the description of the embodiment described in detail above, the present specification includes disclosure of various technical ideas including the invention described below.

  (Invention 1): A lens position detection device for detecting a position of a lens in which an intermediate cylinder is arranged inside a fixed cylinder formed in a cylindrical shape and configured to be movable in the optical axis direction inside the intermediate cylinder. A first sheet coil provided on a lens frame that holds the lens, a second sheet coil provided on the fixed cylinder at a position facing the first sheet coil, and the first sheet. One of the coil and the second sheet coil is an excitation coil, the other is a detection coil, an excitation circuit for supplying an excitation signal to the excitation coil, and the first sheet coil is moved along the movement of the lens frame. By moving in a plane parallel to the second sheet coil while maintaining a facing distance to the second sheet coil, the lens is generated by an electric signal output from the detection coil according to the movement position. Lens position detection apparatus characterized by comprising a signal processing circuit for detecting the position.

  (Invention 2): In the lens position detection device according to Invention 1, either one of the first sheet coil and the second sheet coil is formed at a spatial position in which the phase is different by 90 ° in terms of electrical angle. The lens position is a two-phase coil having a first coil pattern and a second coil pattern, and the other sheet coil is a one-phase coil on which a third coil pattern is formed. Detection device.

  A two-phase excitation and one-phase detection method can be adopted, and a one-phase excitation and two-phase detection method can also be adopted.

  (Invention 3): The lens position detection device according to Invention 2, wherein the two-phase coil is used as the excitation coil, and the one-phase coil is used as the detection coil.

  (Invention 4): In the lens position detection device according to Invention 2 or 3, the first sheet coil is the one-phase coil, and the second sheet coil is the two-phase coil. Lens position detection device.

  Considering the number of wires for obtaining electrical connection, etc., it is preferable to arrange a two-phase coil in the fixed part and a one-phase coil in the movable part.

  (Invention 5): In the lens position detection device according to any one of Inventions 1 to 4, the intermediate cylinder is a rotating cylinder configured to be rotatable with respect to the fixed cylinder. Lens position detection device.

  (Invention 6): A lens barrel that holds a fixed cylinder formed in a cylindrical shape, an intermediate cylinder disposed inside the fixed cylinder, and a lens configured to be movable in the optical axis direction inside the intermediate cylinder. A driving mechanism for moving the lens frame in the optical axis direction, a first sheet coil provided on the lens frame, and a second provided on the fixed cylinder at a position facing the first sheet coil. A sheet coil, an excitation circuit in which one of the first sheet coil and the second sheet coil is an excitation coil and the other is a detection coil, and an excitation signal for supplying an excitation signal to the excitation coil, and movement of the lens frame Accordingly, the first sheet coil moves in a plane parallel to the second sheet coil while maintaining a facing distance from the second sheet coil, so that the first coil is output from the detection coil according to the movement position. Lens apparatus characterized by comprising a signal processing circuit for detecting the position of the lens by an electrical signal that.

  ADVANTAGE OF THE INVENTION According to this invention, the highly reliable lens apparatus which can detect the absolute position of a lens with high precision with a compact structure is realizable. Note that the present invention can be applied to various lens devices such as a lens device for a television camera, a lens device for a video camera, and a lens device for a photographic camera.

  (Invention 7): The lens apparatus according to Invention 6, wherein the intermediate cylinder is a rotating cylinder configured to be rotatable with respect to the fixed cylinder.

The perspective view which shows the structural example of the detection part in the lens position detection apparatus which concerns on embodiment of this invention. Configuration diagram showing a configuration example of a lens apparatus 2 is a cross-sectional view of the lens device shown in FIG. 2 as viewed from the optical axis direction. Schematic showing the configuration of the lens device to which the resolver is applied The block diagram which shows the example of a circuit structure of the lens apparatus which applied the lens position detection apparatus of a two-phase excitation single phase detection system Schematic showing the configuration of a lens apparatus to which an MR sensor is applied

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Sheet coil, 20 ... Sheet coil, 30 ... Resolver, 32 ... Excitation coil, 32A ... 1st excitation coil pattern, 32B ... 2nd excitation coil pattern, 36 ... Detection coil, 100 ... Lens apparatus, 110 ... Lens barrel 112 ... Lens barrel body (fixed cylinder) 116 ... Movable lens 122 ... Holding frame 130 ... Cam cylinder 142 ... Connecting shaft 171 ... First sheet coil 172 ... Second sheet coil 212, 214 ... Excitation Circuit 220: Detection circuit 230 ... Signal processing circuit 240 ... Lens position control circuit

Claims (7)

A lens position detecting device for detecting a position of a lens, in which an intermediate cylinder is arranged inside a fixed cylinder formed in a cylindrical shape and configured to be movable in the optical axis direction inside the intermediate cylinder,
A first sheet coil provided on a lens frame holding the lens;
A second sheet coil provided at a position facing the first sheet coil of the fixed cylinder;
One of the first sheet coil and the second sheet coil is an excitation coil, the other is a detection coil, and an excitation circuit for supplying an excitation signal to the excitation coil;
As the lens frame moves, the first sheet coil moves in a plane parallel to the second sheet coil while maintaining a facing distance from the second sheet coil, and accordingly, according to the movement position. A signal processing circuit for detecting the position of the lens by an electrical signal output from the detection coil;
A lens position detection device comprising: The lens position detection device according to claim 1,
Either one of the first sheet coil and the second sheet coil has a first coil pattern and a second coil pattern formed at a spatial position with a phase difference of 90 ° in electrical angle. Phase coil,
The other sheet coil is a one-phase coil in which a third coil pattern is formed. The lens position detection device according to claim 2,
A lens position detecting apparatus using the two-phase coil as the excitation coil and the one-phase coil as the detection coil. In the lens position detection device according to claim 2 or 3,
The first sheet coil is the one-phase coil;
The lens position detecting device, wherein the second sheet coil is the two-phase coil. In the lens position detection device according to any one of claims 1 to 4,
The lens position detecting device according to claim 1, wherein the intermediate cylinder is a rotary cylinder configured to be rotatable with respect to the fixed cylinder. A fixed cylinder formed in a cylindrical shape;
An intermediate cylinder disposed inside the fixed cylinder;
A lens frame holding a lens configured to be movable in the optical axis direction inside the intermediate cylinder;
A drive mechanism for moving the lens frame in the optical axis direction;
A first sheet coil provided on the lens frame;
A second sheet coil provided at a position facing the first sheet coil of the fixed cylinder;
One of the first sheet coil and the second sheet coil is an excitation coil, the other is a detection coil, and an excitation circuit for supplying an excitation signal to the excitation coil;
As the lens frame moves, the first sheet coil moves in a plane parallel to the second sheet coil while maintaining a facing distance from the second sheet coil, and accordingly, according to the movement position. A signal processing circuit for detecting the position of the lens by an electrical signal output from the detection coil;
A lens device comprising: The lens device according to claim 6,
The lens apparatus according to claim 1, wherein the intermediate cylinder is a rotating cylinder configured to be rotatable with respect to the fixed cylinder.

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