JP2014021265A - Lens drive device and optical equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To install a sensor of a position detection encoder, a flexible circuit board and a sensor holding member in a smaller space.SOLUTION: A lens drive device 24 includes: a first member 26 and a second member 25 relatively movable to each other; a scale member 35 and a sensor holding member 37 mounted respectively on the first and second members; and a sensor 36 held by the sensor holding member and outputting an electric signal with the above relative movement; a flexible circuit board 44 mounting the sensor; and a sensor biasing member 37j biasing the sensor toward the scale. The flexible circuit board includes a first wiring part extending in one side of directions of the relative movement and a second wiring part extending from the other side to the one side. The second wiring part is folded back on a line along the direction of the relative movement with respect to the first wiring part and interposed between the sensor and the sensor biasing member.

Description

  The present invention relates to a lens driving device mounted on an optical apparatus such as an interchangeable lens, a video camera, and a digital still camera.

  Many of the optical devices as described above are provided with an autofocus (AF) function that detects a focus state with respect to a subject of the optical system and moves a focus lens according to the detected focus state to obtain a focused state. Yes. The AF function requires a position detection encoder for detecting the position of the focus lens. Patent Documents 1 and 2 disclose optical position detection encoders in which a reflective scale on which a scale pattern is formed and an optical reading sensor facing the scale are relatively moved (relatively rotated). Patent Document 2 discloses a configuration in which the accuracy of the gap between the sensor and the reflection scale, that is, the position detection accuracy is improved by positioning and holding the sensor with the sensor holder.

JP2011-99869A JP 2007-47652 A (paragraphs 0060-0068 etc.)

  In the position detection encoder disclosed in Patent Document 2, a sensor is mounted on a flexible substrate and is held by a sensor holder together with the flexible substrate. Although not specified in Patent Document 2, this flexible substrate has a wiring portion extending on one side in the relative rotation direction with respect to the sensor on one side of the sensor mounting side, and the other side in the relative rotation direction with respect to the sensor. Wiring portion extending (around) from one side to the other side. For this reason, the width of the flexible substrate and the sensor holder in the central axis direction of the relative rotation (direction orthogonal to the relative movement direction) is considerably larger than the width of the sensor itself in the same direction. Such a configuration requires a large installation space for the sensor including the flexible substrate and the sensor holder, which may hinder downsizing of the optical device.

  The present invention provides a lens driving device and an optical apparatus that have high position detection accuracy and can install a sensor, a flexible substrate, and a sensor holding member in a smaller space.

  A lens driving device according to one aspect of the present invention is attached to a first member and a second member that can move relative to each other when driving a lens, and a scale pattern in the direction of the relative movement. The formed scale member, a sensor holding member attached to the second member, and held by the sensor holding member so as to face the scale member, and outputs an electrical signal corresponding to the scale pattern with the relative movement. And a flexible board on which the sensor is mounted, and a sensor urging member that urges the sensor toward the scale member. The flexible substrate includes a first wiring portion extending to one side in the relative movement direction with respect to the sensor, and a second wiring extending from the other side in the relative movement direction to the one side with respect to the sensor. Part. The second wiring portion is folded back along a line along the relative movement direction with respect to the first wiring portion and is sandwiched between the sensor and the sensor biasing member.

  An optical apparatus having the lens driving device and an optical system including a lens driven by the lens driving device constitutes another aspect of the present invention.

  According to the present invention, since the second wiring portion of the flexible board on which the sensor is mounted is folded back in the direction perpendicular to the relative movement direction, the width of the flexible board and the sensor holder in the direction perpendicular to the relative movement direction is increased. Can be small. Further, the sensor is biased in the direction of the scale member together with the flexible substrate by the sensor biasing member in the folded state. For this reason, it is possible to realize a lens driving device having a high gap accuracy between the sensor and the scale member, that is, a high position detection accuracy and enabling space-saving installation of the sensor, and an optical apparatus including the lens driving device.

1 is a cross-sectional view of a focus drive unit that is an embodiment of the present invention. FIG. 3 is a cross-sectional view illustrating a schematic configuration of an interchangeable lens including the focus driving unit of the embodiment and a single-lens reflex camera equipped with the interchangeable lens. The disassembled perspective view of the said interchangeable lens. FIG. 3 is an exploded perspective view of a focus lens unit including the focus drive unit. FIG. 3 is a perspective view of a cam cylinder included in the focus lens unit. The perspective view and back view of the said focus drive unit. FIG. 3 is an exploded perspective view of the focus drive unit. FIG. 3 is a schematic diagram of an optical position detection encoder provided in the focus drive unit. The figure which shows the scale of the drive ring and optical position detection encoder which are contained in the said focus drive unit. The side view and sectional drawing which show the attachment structure to the drive ring of the said scale. The figure which shows the attachment structure of the sensor unit of the optical position detection encoder with respect to the drive base contained in the said focus drive unit. The perspective view of the said sensor unit. The perspective view which shows the assembly procedure to the sensor holder of the sensor head and sensor board | substrate in the said sensor unit. The expanded sectional view which shows the attachment structure of the sensor unit with respect to the said drive base.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 2 shows a configuration of a camera system including an interchangeable lens as an optical apparatus including a lens driving device that is an embodiment of the present invention, and a digital single-lens reflex camera to which the interchangeable lens is attached. Reference numeral 1 denotes a camera, and reference numeral 2 denotes an interchangeable lens. Reference numeral 1 a denotes a mount portion provided in the camera 1, and reference numeral 2 a denotes a mount portion provided in the interchangeable lens 2. These mount parts 1a and 2a can be attached and detached by bayonet coupling. The camera 1 and the interchangeable lens 2 perform electrical communication via electrical contacts (not shown) provided on the mount portions 1a and 2a.

  In the camera 1, 3 is a main mirror, 4 is a pentaprism, and 5 is a finder lens. The subject image formed by the photographing optical system in the interchangeable lens 2 is reflected by the main mirror 3, converted into an erect image by the pentaprism 4, and observed through the finder lens 5. 6 is a sub-mirror, and 7 is a focus detection unit. Of the light from the photographing optical system, the light transmitted through the main mirror 3 is reflected by the sub mirror 6 and guided to the focus detection unit 7. The focus detection unit 7 includes a field lens, a secondary imaging lens, and an AF sensor, and detects the focus state of the photographing optical system using a phase difference detection method.

  Reference numeral 8 denotes an image sensor, which is composed of a photoelectric conversion element such as a CCD sensor or a CMOS sensor. Since the light receiving surface of the image sensor 8 and the light receiving surface of the AF sensor of the focus detection unit 7 are in a conjugate positional relationship, the focus detection unit 7 can detect the focus state on the image sensor 8 of the photographing optical system. it can. A display panel 9 is provided on the back surface of the camera 1 and displays an image (live view image or captured image) generated using the image sensor 8.

  Next, the photographing optical system in the interchangeable lens 2 will be described. In order from the object side (hereinafter also referred to as the front side) to the image side (hereinafter also referred to as the rear side), L1 is the first lens group, L2 is the second lens group, L3 is the third lens group, and L4 is the fourth lens group. , L5 is a fifth lens group, and L6 is a sixth lens group. AX is the optical axis of the photographing optical system. The direction in which the optical axis AX extends is hereinafter referred to as the optical axis direction.

  The first lens group L1, the third lens group L3, the fifth lens group L5, and the sixth lens group L6 are lens groups that are fixed in the optical axis direction. On the other hand, the second lens group L2 and the fourth lens group L4 are focus lens groups that move in the optical axis direction to perform focusing. Above the optical axis AX, the second lens group L2 and the fourth lens L4 indicate positions in a state where the photographing optical system is focused on a subject at infinity. On the other hand, on the lower side of the optical axis AX, the second lens group L2 and the fourth lens L4 indicate positions in a state where the photographing optical system is focused on the subject at the closest distance.

  Reference numeral 10 denotes a stop, which is disposed between the second lens unit L2 and the third lens unit L3, and adjusts the amount of light toward the image sensor 8 by changing the aperture diameter of the stop.

  FIG. 3 shows the interchangeable lens 2 in an exploded manner. Reference numeral 11 denotes a first lens unit that holds the first lens unit L1, and 12 denotes a second lens unit that holds the second lens unit L2. Reference numeral 13 denotes a third lens unit that holds the third lens unit L3 and the diaphragm 10, and reference numeral 14 denotes a fourth lens unit that holds the fourth lens unit L4. Reference numeral 15 denotes a fifth lens unit that holds the fifth lens unit L5 and the sixth lens unit L6.

  Reference numeral 16 denotes a front fixing ring unit having a transparent window portion 16a. Reference numeral 17 denotes a rear side fixing ring unit, reference numeral 18 denotes a main board, and reference numeral 19 denotes a lens mount unit. Reference numeral 20 denotes a focus unit that holds the third lens unit 13 fixed in the optical axis direction and moves the second lens unit 12 and the fourth lens unit 14 in the optical axis direction (this will be described later). including. Reference numeral 20 a denotes a manual operation ring provided in the focus unit 20. When the photographer manually rotates the manual operation ring 20a and rotates it around the optical axis, the second and fourth lens units 12 and 14 move in the optical axis direction, and manual focusing is performed. Reference numeral 20b denotes a distance index for displaying the subject distance, and the photographer can check the subject distance through the transparent window portion 16a of the fixed ring unit 16.

  A camera controller (CPU or the like) (not shown) mounted on the camera 1 moves the second and fourth lens units 12 and 14 in the optical axis direction based on the focus state detection result obtained by the focus detection unit 7. The amount to be made (focus drive amount) is calculated. Then, the camera controller communicates the calculated focus drive amount to a lens controller (not shown) mounted on the main board 18 of the interchangeable lens 2. The lens controller drives a focus motor (described later) mounted on the interchangeable lens 2 to move the second and fourth lens units 12 and 14 in the optical axis direction. Thereby, an autofocus (AF) operation is performed. After the in-focus state of the photographic optical system is obtained by manual focusing or AF operation, the main and sub mirrors 3 and 6 are retracted out of the optical path in response to an operation of a photographic switch (not shown) provided in the camera 1. The subject image is photoelectrically converted by the image sensor 8. Thereby, a captured image is generated.

  Next, the configuration of the focus unit 20 will be described in more detail with reference to FIGS. 4 and 5. FIG. 4 shows an exploded view of the focus lens unit 23 provided in the focus unit 20. The second lens unit 12 has three cam follower pins 12a on the outer periphery thereof. The third lens unit 13 has three support pins 13a on the outer periphery thereof. Further, the fourth lens unit 14 has three cam follower pins 14a on the outer periphery thereof.

  21 is a guide tube. Three cam follower pins 12a of the second lens unit 12 are engaged with three rectilinear grooves 21a formed in the front peripheral wall portion of the guide tube 21 so as to extend in the optical axis direction. As a result, the second lens unit 12 is held movably in the optical axis direction. Further, three cam follower pins 14a of the fourth lens unit 14 are engaged with the three rectilinear grooves 21c formed in the rear peripheral wall portion of the guide cylinder 21 so as to extend in the optical axis direction. As a result, the fourth lens unit 14 is held movably in the optical axis direction. Further, the three support pins 13a of the third lens unit 13 are engaged with the three holes 21b formed in the rear peripheral wall portion of the guide tube 21, whereby the third lens unit 13 is connected to the optical axis. It is held in a fixed state.

  Reference numeral 22 denotes a cam cylinder disposed inside the guide cylinder 21. FIG. 5 shows the cam cylinder 22. The cam barrel 22 has three second cam groove portions 22a and four fourth cam groove portions 22c that are engaged with the three cam follower pins 12a of the second lens unit 12 and the cam follower pins 14a of the fourth lens unit 14, respectively. Is formed. 22d is an interlocking pin provided on the outer periphery of the cam cylinder 22, and has a portion (interlocking part) protruding from a circumferentially extending groove 21d formed on the rear peripheral wall of the guide cylinder 21 as shown in FIG. . Reference numeral 22b denotes a groove extending in the circumferential direction. When the support pin 13a of the third lens unit 13 that does not rotate is inserted into the groove 22b, rotation of the cam cylinder 22 around the optical axis relative to the support pin 13a is allowed. .

  In the focus unit 20 including the focus lens unit 23 configured as described above, the cam cylinder 22 rotates about the optical axis with respect to the guide cylinder 21 by rotating the manual operation ring 20a shown in FIG. Further, the rotational force of the focus motor is transmitted to the cam barrel 22 through a focus drive unit which will be described later, whereby the cam barrel 22 rotates around the optical axis with respect to the guide barrel 21. When the cam barrel 22 rotates, the second and fourth lens units 12 and 14 move in the optical axis direction due to the engaging action of the second and fourth cam groove portions 22a and 22c and the cam follower pins 12a and 14a.

  6, 7 and 1 show the configuration of the focus drive unit 24 as a lens drive device. FIG. 6A shows an assembled state of the focus drive unit 24, and FIG. 6B shows a configuration when viewed from the rear side of the focus drive unit 24 shown in FIG. 6A. FIG. 7 shows the focus drive unit 24 in an exploded manner. FIG. 1 shows a cross section of the focus driving unit 24 taken along line AA shown in FIG.

  Reference numeral 26 denotes a drive ring, which corresponds to a first member. Reference numeral 25 denotes a drive base, which corresponds to the second member. The drive ring 26 rotates around the optical axis with respect to the drive base 25 on the outer periphery of the drive base 25. That is, the drive ring 26 and the drive base 25 can be rotated relative to each other. A connection key 27 is fixed to the drive ring 26 with two screws (see FIG. 9). The connection key 27 engages with the interlocking portion of the interlocking pin 22d provided on the cam cylinder 22 shown in FIG.

  28 is a manual interlocking ring, and 29 is a sliding ring. The inner peripheral surface of the front side of the sliding ring 29 is fitted to the outer peripheral surface of the rear end of the front cylindrical portion (large diameter portion) of the drive base 25. Further, the inner peripheral surface on the front side of the manual interlocking ring 28 is rotatably fitted to the outer peripheral surface of the sliding ring 29.

  30 is a USM interlocking ring, and 31 is a USM rotor. 32 is a USM stator unit including a plate spring for pressurization, and 33 is a stator rotation stop ring. The USM rotor 31, the USM stator unit 32, and the stator rotation stop ring 33 constitute a vibration type motor as a focus motor. When energized, the USM stator unit 32 generates vibration that travels in the circumferential direction (around the optical axis), and rotates the USM rotor 31 that is in pressure contact with the urging force of the pressurizing leaf spring around the optical axis. To drive. The USM interlocking ring 30 is integrated with the USM rotor 31 and rotates around the optical axis.

  Reference numeral 34 denotes a differential roller, and three differential rollers 34 are rotatably attached to each of three shaft portions 26 a provided on the outer periphery of the drive ring 26. These differential rollers 34 are sandwiched between the USM interlocking ring 30 and the manual interlocking ring 28 that are urged to the front side via the USM rotor 31 by the urging force of the pressurizing leaf spring of the USM stator unit 32. 26 is supported in the optical axis direction. Thereby, the drive ring 26 is rotatably supported at a fixed position in the optical axis direction.

  As described above, when the USM rotor 31 and the USM interlocking ring 30 rotate around the optical axis, the drive ring 26 rotates around the optical axis while the differential roller 34 rolls with respect to the non-rotating manual interlocking ring 28. . When the manual interlocking ring 28 is rotated around the optical axis, the drive ring 26 rotates around the optical axis while the differential roller 34 rolls with respect to the USM interlocking ring 30 that is not rotating. The manual interlocking ring 28 is engaged with the manual operation ring 20a so that rotation can be transmitted. For this reason, when the manual operation ring 20a is rotated around the optical axis, the drive ring 26 rotates around the optical axis. That is, the drive ring 26 can always be rotated either electrically or manually.

  Reference numeral 35 denotes a film scale (hereinafter simply referred to as a scale) constituting a scale member of the optical position detection encoder. The scale 35 is a belt-like and flexible reflective scale, and is attached to the drive ring 26 along its inner peripheral surface (see FIG. 9).

  Reference numeral 36 denotes a sensor head constituting an optical reading sensor of an optical position detection encoder, and a scale 35 is provided by a sensor holder 37 as a sensor holding member attached to the outer peripheral surface of the rear cylinder portion (small diameter portion) of the drive base 25. It is held so as to face.

  Reference numeral 38 denotes a guide roller, and 39 denotes a roller shaft that rotatably supports the guide roller 38. The roller shaft 39 is fixed to the drive base 25. The guide roller 38 supports the drive ring 26 so as to be rotatable around the optical axis at a fixed position in the optical axis direction with respect to the drive base 25.

  FIG. 8 schematically shows the above-described optical position detection encoder. The Y-axis direction in FIG. 8 corresponds to the optical axis direction of the photographing optical system, and the X-axis direction corresponds to the direction around the optical axis. The optical axis direction is a direction in which the central axis of relative rotation of the drive base 25 and the drive ring 26 extends, and is also a direction orthogonal to the direction of the relative rotation. The direction around the optical axis is the direction of relative rotation between the drive base 25 and the drive ring 26. The Z-axis direction corresponds to a direction orthogonal to the optical axis (the radial direction of the drive base 25 and the drive ring 26).

  Two reflective scale patterns 35 a and 35 b extending in the X-axis direction are formed on the surface of the scale 35 that faces the sensor head 36. A light source 36a, which is an LED chip, is disposed on the surface of the sensor head 36 facing the scale 35, and two photo IC chips each incorporating a signal processing circuit so as to sandwich the light source 36a in the Y-axis direction. 36b and 36c are arranged. Photodiode arrays 36d and 36e, which are light receiving elements, are mounted on the photochip IC chips 36b and 36c, respectively.

  Reference numeral 36f denotes a base substrate formed of a printed circuit board. The light source 36a and the photochip ICs 36b and 36c mounted on the base substrate 36f are covered with a transparent resin layer (not shown) formed on the base substrate 36f and a protective glass (not shown) disposed on the resin layer. It has been broken.

  When the sensor head 36 and the scale 35 move relative to each other in the X-axis direction (in this embodiment, the scale 35 moves relative to the sensor head 36), part of the light emitted from the light source 36a is reflected by the reflective scale pattern 35a. It is reflected and reaches the photodiode array 36d. Further, another part of the light emitted from the light source 36a is reflected by the reflection scale pattern 35b and reaches the photodiode array 36e. As a result, the photo IC chips 36b and 36c optically read the reflective scale patterns 35a and 35b, respectively, and output electrical signals having a period corresponding to the pitch of the reflective scale patterns 35a and 35b. Although not shown, the pitches of the reflection scale patterns 35a and 35b are different from each other, and position detection with high resolution can be performed using electrical signals having different periods output from the photo IC chips 36b and 36c.

  FIG. 9 shows a drive ring unit including a drive ring 26, a differential roller 34, a connection key 27, and a scale 35 integrated with the drive ring 26. In FIG. 9, the positions of the sensor head 36 and the guide roller 38 (roller shaft 39) relative to the drive ring unit are also shown (in a state floating in the air). The guide roller 38 (roller shaft 39) is held by a guide roller holder 45 attached to the drive base 25 so as to be movable in the radial direction, and is urged from the drive base 25 side toward the drive ring 26 side. . FIG. 10A shows a configuration when viewed from the side of the drive ring unit, and FIG. 10B shows the drive ring unit taken along line BB shown in FIG. 10A. A cross section is shown.

  In these figures, reference numeral 40 denotes a scale holding sheet metal that holds one end of the scale 35 in the longitudinal direction (corresponding to the direction around the optical axis, hereinafter also referred to as the circumferential direction). The scale holding metal plate 40 is disposed in a holding groove 26e formed in the drive ring 26 so as to extend in the circumferential direction, and is allowed to move in the circumferential direction while being prevented from moving in the optical axis direction and the radial direction. Is held by a drive ring 26. Reference numeral 41 denotes a ball that engages in the optical axis direction with a ball groove portion 40d formed in the scale holding metal plate 40 so as to extend in the circumferential direction and a ball groove portion 26d formed in the drive ring 26 so as to extend in the circumferential direction. When the ball 41 is engaged with the ball groove portions 40d and 26d, the scale holding metal plate 40 is positioned in the optical axis direction while being allowed to move in the circumferential direction. Reference numeral 26b denotes a holding projection which is provided on the inner peripheral surface of the drive ring 26 and holds the other end in the longitudinal direction of the scale 35 in the circumferential direction and the radial direction. The scale 35 is prevented from being displaced in the optical axis direction by a step portion 26 f formed on the inner peripheral surface of the drive ring 26 so as to extend in the circumferential direction.

  Reference numeral 42 denotes a scale urging spring composed of a compression coil spring, and reference numeral 43 denotes a spring cover for preventing the scale urging spring 42 from falling off. The scale biasing spring 42 is disposed between the fixed portion 26 c provided on the drive ring 26 and the spring receiving portion 40 a of the scale holding metal plate 40, and applies a biasing force toward one end of the scale 35 toward the other end side. Yes. For this reason, the scale 35 is always pressed against the inner peripheral surface of the drive ring 26.

  According to such a configuration, even if the scale 35 expands and contracts in the circumferential direction due to high or low temperature, moisture absorption, or the like, an excessive force is applied to the scale 35 as in the case where both ends of the scale are firmly fixed to the drive ring. It acts and can prevent the scale 35 from being distorted. Therefore, it can be avoided that the reading accuracy of the scale 35 (reflection scale patterns 35a and 35b) by the sensor head 36 is lowered.

  11 and 14 show a structure for mounting the sensor head 36 and the sensor holder 37 to the drive base 25. FIG. Reference numeral 44 denotes a flexible substrate (hereinafter referred to as a sensor substrate) on which the sensor head 36 is mounted. On one side of the sensor board 44 on which the sensor head 36 is mounted, power is supplied from the main board 18 shown in FIG. 3 to the sensor head 36, or an electric signal from the sensor head 36 is sent to the main board 18. A wiring pattern for this purpose is formed. As the sensor substrate 44, a double-sided substrate having wiring patterns formed on both sides thereof can be used. However, since the double-sided substrate is generally expensive, a single-sided substrate is used in this embodiment. FIG. 12 shows a sensor unit including a sensor head 36 and a sensor holder 37 mounted on the sensor substrate 44. Further, FIGS. 13A to 13C show a procedure for assembling the sensor head 36 and the sensor substrate 44 to the sensor holder 37. FIG.

  FIG. 13A shows the sensor substrate 44 in an expanded state. The sensor substrate 44 extends from the other side in the direction around the optical axis to the one side with respect to the sensor head 36 from the other side in the direction around the optical axis. A second wiring portion 44b extending in this manner. The first wiring portion 44a and the second wiring portion 44b join at the third wiring portion 44c and are connected to the main substrate 18.

  When assembling such a sensor substrate 44 to the sensor holder 37, first, the second wiring portion 44b is placed on the back side of the first wiring portion 44a along a line D along the direction around the optical axis shown in FIG. It is folded back (on the side opposite to the mounting surface of the sensor head 36). Accordingly, as shown in FIGS. 13B and 13C, the width of the sensor substrate 44 to be held by the sensor holder 37 in the optical axis direction is made substantially the same as the width of the sensor head 36 in the same direction. be able to.

  As shown in FIGS. 11, 12, and 13A, the sensor holder 37 is formed with a positioning hole portion 37a and a long hole portion 37b. Positioning pins 25a and 25b provided on the drive base 25 engage with the positioning hole portion 37a and the elongated hole portion 37b, so that the position of the sensor holder 37 in the optical axis direction with respect to the drive base 25 and in the direction around the optical axis. Is decided.

  Further, as shown in FIGS. 12 and 13A and 13C, the sensor holder 37 is formed with two urging arm portions 37c and two retracting arm portions 37d. The sensor holder 37 is attached to the drive base 25 by holding a sensor attachment portion (not shown) provided on the drive base 25 by the urging arm portion 37c and the two retracting arm portions 37d.

  An optical axis direction reference wall portion 37e and an optical axis direction spring portion 37f are formed on one side and the other side in the optical axis direction of the sensor holder 37, respectively. When the sensor substrate 44 is abutted against the optical axis direction reference wall portion 37e by the biasing force of the optical axis direction spring portion 37f, the position of the sensor head 36 in the optical axis direction with respect to the sensor holder 37 (that is, the drive base 25) is changed. It is decided.

  A circumferential reference wall portion 37i is formed on one side of the sensor holder 37 in the direction around the optical axis (the side on which the first wiring portion 44a extends), and a substrate holding portion 37k is formed on the other side. Has been. One side surface in the circumferential direction of the sensor head 36 is abutted against the circumferential reference wall portion 37i, and the end portion on the other circumferential side of the sensor substrate 44 is held by the substrate holding portion 37k. The position around the optical axis is determined.

  Further, on both sides in the optical axis direction of the sensor holder 37, gap reference wall portions 37g and 37h are formed so as to face the surface of the sensor substrate 44 (the mounting surface of the sensor head 36 in the first wiring portion 44a). Yes. Further, on both sides of the sensor holder 37 around the optical axis, as shown in FIGS. 13A to 13C, sensor urging springs 37j as sensor urging members are integrally provided on the sensor holder 37. . The sensor urging spring 37j has a leaf spring shape, and as shown in FIG. 14, abuts against the back surface (second wiring portion 44b) of the sensor substrate 44, and the sensor head 36 and the sensor head 36 together with the gap reference wall. It urges | biases to the part 37g, 37h side. Thereby, the surface of the sensor substrate 44 is abutted against the gap reference wall portions 37g and 37h, and the gap with the scale 35 of the sensor head 36 is determined. The sensor head 36 is bonded and fixed to the sensor holder 37 after the above positioning. The bonding position is preferably an elliptical position indicated by a broken line indicated by an arrow C in FIG. By adhering and fixing the sensor substrate 44 and the sensor holder 37, it is possible to prevent the adhesive from flowing into the sensor head 36 which is an optical element and the output of the sensor head 36 from being deteriorated.

  According to the configuration of the sensor unit described above, the sensor head 36 can be accurately positioned with respect to the scale 35 in the optical axis direction, the direction around the optical axis, and the gap direction (radial direction). It is possible to realize a position detection encoder having the same. That is, an interchangeable lens having high position control accuracy of the focus lenses (L2, L4) can be realized. In addition, since the space in the optical axis direction and the gap direction for arranging the sensor unit can be reduced, the focus unit 20 and the interchangeable lens 2 can be reduced in size.

  In the above embodiment, the case where the sensor urging spring 37j is formed integrally with the sensor holder 37 as a leaf spring portion has been described. However, a sensor urging force such as a leaf spring or a compression coil spring as a separate member from the sensor holder 37 is described. A member may be attached to the drive base 25.

  In the above embodiment, the case where the scale 35 moves relative to the fixed sensor head 36 has been described. However, the sensor head may move relative to the fixed scale. That is, the sensor and the scale may be moved relative to each other.

  In the above-described embodiments, the optical position detection encoder has been described. Alternatively, a magnetic position detection encoder having a magnetic sensor as a sensor in which a magnetic scale pattern is formed on the scale may be used.

  Further, in the above-described embodiment, the case where the position detection encoder is provided on the interchangeable lens has been described. However, the position detection encoder is a lens-integrated camera (video camera, still camera) or other movable lens using a similar mounting structure. You may mount in various optical apparatuses.

  Each embodiment described above is only a representative example, and various modifications and changes can be made to each embodiment in carrying out the present invention.

  A small optical device (a camera, an interchangeable lens, etc.) provided with a position detection encoder can be provided.

24 focus drive unit 25 drive base (second member)
26 Drive ring (first member)
35 Scale (Scale member)
36 Sensor head (sensor)
37 Sensor holder (sensor holding member)
37j Sensor biasing spring (sensor biasing member)
44 Sensor substrate (flexible substrate)
44a 1st wiring part 44b 2nd wiring part

Claims (4)

A lens driving device for driving a lens,
A first member and a second member capable of moving relative to each other when driving the lens;
A scale member attached to the first member and having a scale pattern formed in the direction of relative movement;
A sensor holding member attached to the second member;
A sensor that is held by the sensor holding member so as to face the scale member, and outputs an electrical signal corresponding to the scale pattern with the relative movement;
A flexible substrate on which the sensor is mounted;
A sensor urging member for urging the sensor in the direction of the scale member together with the flexible substrate;
The flexible substrate includes a first wiring portion extending to one side in the relative movement direction with respect to the sensor, and a first wiring portion extending from the other side in the relative movement direction to the one side with respect to the sensor. 2 wiring parts,
The second wiring portion is folded back along a line along the direction of relative movement with respect to the first wiring portion, and is sandwiched between the sensor and the sensor biasing member. A lens driving device.   The lens driving device according to claim 1, wherein the sensor urging member is provided integrally with the sensor holding member.   The lens driving device according to claim 1, wherein the sensor is held by the sensor holding member by bonding the sensor holding member and the flexible substrate. A lens driving device according to claim 1;
And an optical system including a lens driven by the lens driving device.