JP2008039942A - Optical apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical apparatus capable of easily suppressing the occurrence of gouging between a feed screw and a rack and the increase of driving resistance. <P>SOLUTION: The optical apparatus includes: a holding member 3 for holding an optical element 4; the rack attached to the holding member; and the feed screw 8a that rotates engaging with the rack so as to drive the holding member. The rack comprises a first member 5 and a second member 6 as a member other than the first member, separately having tooth parts 5c and 6a to be engaged with the feed screw. The tooth parts of the first and second members are arranged opposite to each other across the feed screw, and also, inclined opposite to each other in a direction orthogonal to the axial direction of the feed screw. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical apparatus including a drive mechanism that drives an optical element such as a lens.

  Optical devices such as a digital still camera, a video camera, and an interchangeable lens are provided with a lens driving mechanism that moves a movable holding member that holds a lens in the optical axis direction for zooming and focus adjustment. In such a lens drive mechanism, the rack mounted on the movable holding member is meshed with a feed screw that is rotationally driven by a motor, whereby the rotational force of the feed screw is driven in the optical axis direction of the movable holding member (lens). There is something that converts to force.

For example, in the lens driving mechanism disclosed in Patent Literature 1, rack teeth having an apex angle equal to the apex angle of the feed screw are formed in the rack so as to extend in a direction perpendicular to the axial direction of the feed screw. ing. The rack is integrally formed with a pressing portion that sandwiches the feed screw between the rack teeth. A convex portion having a vertex angle larger than the screw thread angle of the feed screw is formed on the pressing portion. As a result, the generation of sliding noise due to the pressing portion being in contact with the outer periphery of the feed screw over the entire surface thereof is prevented. The convex portion is also formed to extend in a direction perpendicular to the axial direction of the feed screw.
JP-A-8-248284 (paragraphs 0012 to 0018, FIGS. 1 to 4)

  However, in the lens driving mechanism disclosed in Patent Document 1, since the rack teeth and the convex portions extend in a direction perpendicular to the axial direction of the feed screw, a twist is generated between the rack and the feed screw during lens driving. Or the driving resistance increases.

  In order to avoid the occurrence of twisting and the increase in driving resistance, it is conceivable to incline the rack teeth and the convex portion according to the lead angle of the feed screw. In this case, since the rack teeth and the convex portions are arranged on the opposite sides of the feed screw, their inclination directions are opposite to each other. However, since the rack disclosed in Patent Document 1 is an integrally molded part, the formation of rack teeth and protrusions inclined in opposite directions in this way is used for manufacturing the rack. Mold making is very difficult.

  An object of the present invention is to provide an optical apparatus that can easily suppress the occurrence of a twist between a feed screw and a rack and an increase in driving resistance.

  An optical apparatus according to one aspect of the present invention includes a holding member that holds an optical element, a rack that is attached to the holding member, and a feed screw that drives the holding member by rotating while meshing with the rack. The rack includes a first member having a tooth portion that meshes with the feed screw, and a second member that is a member different from the first member. The tooth portions of the first and second members are arranged on opposite sides of the feed screw and are inclined in opposite directions with respect to a direction orthogonal to the axial direction of the feed screw. To do.

  According to the present invention, the rack is constituted by the first member and the second member which is a member different from the first member, so that the rack has tooth portions which are located with the feed screw interposed therebetween and inclined in the opposite directions. The rack can be easily manufactured. Therefore, it is possible to suppress the occurrence of twisting between the rack and the feed screw and the increase in driving resistance when the holding member (optical element) is driven.

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

  FIG. 1 shows the configuration of a lens driving mechanism used in an optical apparatus that is Embodiment 1 of the present invention. 2 and 3 show an enlarged part of the lens driving mechanism.

  In these drawings, reference numeral 1 denotes a first guide bar extending in the optical axis direction. The first guide bar 1 is engaged with a U-groove portion 3b formed in a moving ring 3 described later so as to be movable in the optical axis direction. Reference numeral 2 denotes a second guide bar extending in the optical axis direction. A sleeve portion 3a formed on the moving ring 3 is engaged with the second guide bar 2 so as to be movable in the optical axis direction.

  The moving ring 3 as a holding member holds the lens 4. The moving ring 3 is guided in the optical axis direction by the sleeve portion 3 a engaging the second guide bar 2, and the second guide bar 1 by engaging the U groove portion 3 b with the first guide bar 1. Rotation around the bar 2 is prevented.

  Two flange portions 3e and 3f separated from each other in the optical axis direction are integrally formed on the moving ring 3. The flange portions 3e and 3f are formed with holes 3c and 3d into which shaft portions 5a and 5b (see FIG. 2) formed at both ends in the optical axis direction of the first rack member 5 as the first member are inserted. Has been. Reference numeral 3g denotes an inclined surface inclined with respect to the end face of the flange portion 3f.

  In FIG. 2, a plurality of rack teeth (tooth portions) 5 c are formed on the first rack member 5. The rack teeth 5c are inclined by an angle θ with respect to a direction orthogonal to the direction of the axis A (that is, the optical axis direction) of the feed screw 8a described later. This angle θ is equal to the lead angle of the feed screw 8a. However, “equal” here means not only when they are completely equal, but also when they differ within a range that can be regarded as equal (for example, an allowable error range).

  Reference numeral 6 denotes a second rack member having two rack teeth (tooth portions) 6a inclined at an angle θ with respect to the direction orthogonal to the axis A direction of the feed screw 8a, as shown in FIG. This angle θ is also equal to the lead angle of the feed screw 8a, like the first rack tooth 5c.

  As shown in FIG. 2, the second rack member 6 has the first rack teeth 6a facing the rack teeth 5c of the first rack member 5 (hereinafter, this state is referred to as a rack assembled state). It is attached to the rack member 5. Specifically, a holding shaft portion 5g is formed coaxially with the shaft portions 5a and 5b between the shaft portions 5a and 5b of the first rack member 5, and the connecting portion of the second rack member 6 is formed. 6b is attached to the holding shaft portion 5g so as to be rotatable around the holding shaft portion 5g. These first and second rack members 5 and 6 form one rack.

  The second rack member 6 (connection portion 6b) is movable in the direction of the axis A on the holding shaft portion 5g. However, both sides of the holding shaft portion 5g in the axial direction A abut against the second rack member 6 (connecting portion 6b) to prevent the second rack member 6 from moving further in the axis A direction. Flange portions 5d and 5e are formed. That is, the second rack member 6 can move relative to the first rack member 5 in the direction of the axis A only in the range B between the flange portions 5d and 5e.

  In the rack assembly state, the rack teeth 5c formed on the first rack member 5 and the rack teeth 6a formed on the second rack member 6 have an angle θ opposite to the direction perpendicular to the direction of the axis A. Just leaning. That is, as shown in FIG. 2, when the clockwise direction is +, the rack teeth 5c are inclined by + θ and the rack teeth 6a are inclined by −θ with respect to the direction orthogonal to the axis A direction.

  A coil portion of a torsion coil spring 7 that is an urging member (elastic member) is disposed on the outer periphery of the shaft portion 5 b of the first rack member 5. One end of the coil portion in the axis A direction is in contact with the flange portion 5 e of the first rack member 5. In place of the torsion coil spring 7, other elastic members such as a leaf spring may be used.

  Further, the first arm portion 7 a of the torsion coil spring 7 is locked to a locking portion 5 f formed on the first rack member 5. Further, the second arm portion 7 b of the torsion coil spring 7 is locked to the second rack member 6. As a result, the second rack member 6 is biased around the holding shaft portion 5 g in a direction in which the rack teeth 6 a approach the rack teeth 5 c of the first rack member 5.

  A feed screw 8a is disposed between the rack teeth 5c, 6a of the first and second rack members 5, 6. Both the rack teeth 5c, 6a sandwich the feed screw 8a from both sides in the radial direction by the biasing force from the arm portions 7a, 7b of the torsion coil spring 7 described above.

The rack teeth 5c, 6a of the first and second rack members 5, 6 are arranged on opposite sides of the feed screw 8a, and are opposite to each other with respect to the direction orthogonal to the axial direction of the feed screw 8a. However, although the second rack member 6 has the rack teeth 6 a, it does not have a role of transmitting the driving force in the optical axis direction directly to the moving ring 3, unlike the first rack member 5. Using the biasing force of the torsion coil spring 7, the second rack member 6 is connected to the first rack member 5 so that the rack teeth 5c of the first rack member 5 are surely engaged with the feed screw 8a. This is a member having a role of sandwiching the feed screw 8a.

  In FIG. 1, 9 is a motor and 8 is its output shaft. A feed screw 8 a is formed on the output shaft 8. As the motor 9, various motors such as a stepping motor, a DC motor, and a vibration motor can be used.

  The first rack member 5 is configured such that the shaft portions 5a and 5b described above are inserted into the holes 3c and 3d formed in the flange portions 3e and 3f of the moving ring 3, so It is attached so as to be rotatable around 5a and 5b. A slit connected to the hole 3d is formed in the flange portion 3f, and the shaft portion 6a is inserted into the hole 3d through this slit.

  At this time, the coil portion of the torsion coil spring 7 is compressed between the first rack member 5 (flange portion 5 e) and the flange portion 3 f of the moving ring 3. For this reason, the first rack member 5 is biased toward the shaft portion 5a in the direction of the axis A with respect to the moving ring 3 by the spring force generated in the coil portion. As shown in FIG. 2, a truncated cone part 5h is formed at the base end side portion of the shaft part 5a. The frusto-conical part 5h abuts around the hole 3c in the flange 3e of the moving ring 3, so that the axis of the shaft 5a relative to the hole 3c is avoided and the moving ring 3 of the first rack member 5 is avoided. Can be removed in the direction of the axis A. Therefore, the position of the moving ring 3 can be controlled with high accuracy.

  Further, the first arm portion 7 a of the torsion coil spring 7 abuts on the inclined surface 3 g of the moving ring 3, whereby the urging force of the coil spring 7 is efficiently transmitted to the first rack member 5. And when the 1st rack member 5 and the 1st arm part 7a rotate integrally, it is heavy in the direction which opposes the inclination of the inclined surface 3g, and rotates lightly in the direction which follows an inclination.

  In the lens driving mechanism configured as described above, when the motor 9 is energized and the output shaft 8 is rotated, the first rack member 5 is driven in the axial direction A by the engagement of the feed screw 8a and the rack teeth 5c. Force is generated. This driving force is transmitted to the moving ring 3 and moves the moving ring 3 in the optical axis direction.

  At this time, as described above, the rack teeth 5c and 6a are inclined in opposite directions, and the inclination angle θ is equal to the lead angle of the feed screw 8a, so that the gap between the feed screw 8a and the rack teeth 5c and 6a is There is almost no twisting.

  If the second rack member 6 is fixed in the axial direction A with respect to the first rack member 5, the positional relationship of the rack teeth 5c, 6a in the axis A direction is the thread of the feed screw 8a. One of the rack teeth cannot properly mesh with the feed screw 8a. That is, the drive resistance increases due to a pitch shift between the rack teeth 5c and 6a and the thread. On the other hand, in this embodiment, since the second rack member 6 is allowed to move in the direction of the axis A with respect to the first rack member 5, both the rack teeth 5c and 6a can be fed without difficulty. 8a can be engaged.

  With the above configuration, it is possible to suppress an increase in driving resistance due to twisting and pitch deviation in the lens driving mechanism that drives the moving ring 3 in the optical axis direction.

  Next, the shape of the feed screw portion 8a and the rack teeth 5c and 6a will be described in detail with reference to FIG.

  In FIG. 4, 8a1 is a thread part which meshes with the rack teeth 5c, 6a of the feed screw 8a, and the apex angle (thread angle) is set to θ1. Reference numeral 8a2 denotes a protrusion provided on the outer periphery between adjacent screw threads in the screw portion 8a1, and the apex angle (the opening angle of the adjacent protrusion 8a2) is set to θ2. The protrusion 8a2 has a role of preventing the rack teeth 5c and 6a from shifting in the direction of the axis A with respect to the feed screw 8a when the vibration or impact is applied to the optical apparatus, that is, the tooth skipping.

  On the other hand, the apex angles of the rack teeth 5c and 6a are set to θ3.

These θ1 to θ3 are
θ3 ≦ θ2 <θ1
Have the relationship.

  As a result, the rack teeth 5c, 6a and the threaded portion 8a1 can slide smoothly in a range where the protruding portion 8a2 is avoided, that is, in the vicinity of the thread valley bottom where the vicinity of the outer periphery of the feed screw 8a is avoided. Further, by providing the feed screw 8a with a protrusion 8a2 for preventing tooth skipping in addition to the screw portion 8a1 for transmitting the original driving force, the moving ring 3 can be accurately detected even if vibration or impact is applied. A lens driving mechanism capable of accurate position control can be realized.

  In addition, you may employ | adopt the general rolling screw shape which does not have the projection part 8a2 instead of the shape shown in FIG. 4 as the feed screw 8a.

  Next, the configuration of the optical apparatus of the present embodiment is shown in FIG. Here, the configuration of the video camera will be described. However, the present invention can also be applied to an optical apparatus other than a video camera such as an imaging apparatus such as a digital still camera or an interchangeable lens.

  Reference numeral 220 denotes an image sensor including a CCD sensor, a CMOS sensor, or the like.

  225 is a zoom encoder for detecting the position of the second lens unit L2 as a variator in the optical axis direction, and 227 is a focus encoder for detecting the position of the fourth lens unit L4 as a focus lens in the optical axis direction. . The zoom motor 221 and the focus motor 223 are not limited to a stepping motor, and a DC motor or a vibration type motor can also be used. The second lens unit L2 and the fourth lens unit L4 correspond to the lens 4 shown in FIG.

  Reference numerals 221 and 223 denote a zoom motor and a focus motor, and stepping motors can be used. These motors 221 and 223 correspond to the motor 9 shown in FIG.

  In order to detect the positions of the second and fourth lens units L2 and L4 in the optical axis direction, the lens units are reset to a predetermined reference position, and then the number of drive pulses input to the stepping motor is counted. .

  Further, in order to detect the positions of the second and fourth lens units L2 and L4, a detection method other than the encoder may be employed.

  Reference numeral 226 denotes an aperture encoder. For example, a hall element is disposed inside an aperture motor (meter) that is a drive source of the aperture unit 222 to detect the rotational positional relationship between the rotor and the stator. Thereby, the aperture diameter can be detected.

  Reference numeral 228 denotes a camera signal processing circuit which performs predetermined amplification, gamma correction, and the like on the output of the image sensor 220 to generate a video signal. The contrast signal component of the video signal passes through the AE gate 229 and the AF gate 230. In other words, an optimum signal extraction range for determining exposure and focusing is set in this gate from within the entire screen. The size of the gate may be variable or a plurality of gates may be provided.

  Reference numeral 231 denotes an AF signal processing circuit for AF (autofocus), which generates one or a plurality of outputs related to high-frequency components of the video signal.

  Reference numeral 232 denotes a CPU as a control circuit, which controls the entire control of the optical apparatus.

  Reference numeral 233 denotes a zoom switch for performing zooming. Reference numeral 234 denotes a zoom tracking memory, which stores focus lens position information to be taken according to the subject distance and the position of the variator lens during zooming. Note that the memory in the CPU 232 may be used as the zoom tracking memory.

  For example, it is assumed that the zoom switch 233 is operated by the photographer. The CPU 232 controls the zoom motor 221 and the focus motor 223 so that a predetermined positional relationship between the variator lens and the focus lens calculated based on information in the zoom tracking memory 234 is maintained.

  In the AF operation, the CPU 232 drives and controls the focus motor 223 so that the output of the AF signal processing circuit 231 shows a peak. Further, the CPU 232 controls the aperture motor 222 while monitoring the output of the aperture encoder 226 so that the average value of the output of the video signal (Y signal) that has passed through the AE gate 229 becomes a predetermined value in order to obtain appropriate exposure. To control the aperture diameter.

  A ROM 502 is provided in the CPU 232 and stores table data of MTF characteristics. An external memory may be provided, and the MTF characteristic table data may be stored therein.

  Reference numeral 503 denotes a trigger switch for moving image shooting, and reference numeral 504 denotes a trigger switch for still image shooting. Reference numeral 505 denotes a switch for setting the recording resolution (image resolution) of a still image, and reference numeral 506 denotes an electronic viewfinder configured by a liquid crystal display or the like.

  Reference numeral 507 denotes a still image recording circuit for writing still image information on a recording medium such as a magnetic tape, a semiconductor memory card, or an optical disk. Reference numeral 508 denotes a circuit for reducing the video information from the high-pixel type image sensor 220 to a television format signal. .

  Reference numeral 509 denotes a moving image recording circuit for recording moving image information on a recording medium. An image sensor drive circuit 510 drives the image sensor 220 so that an electronic shutter operation at a predetermined electronic shutter speed (charge accumulation time) is performed at a predetermined timing based on an instruction from the CPU 232.

  When a power switch (not shown) is turned on, in a state where the optical device is set to the recording mode, the video signal obtained by the image sensor 220 is NTSC or PAL by the camera signal processing circuit 228 and the reduction processing circuit 508. TV signal corresponding to the above. An image formed by the television signal is displayed on the electronic viewfinder 506.

  At this time, in order to obtain the optimum exposure, the CPU 232 drives the aperture motor 222 so that the Y signal in the AE gate 229 becomes a predetermined value, and the position of the aperture blade as the aperture state (that is, aperture aperture diameter). Is detected by the diaphragm encoder 226.

  In this state, when the moving image trigger switch 503 is operated by the photographer and a moving image shooting instruction is given, the CPU 232 drives the moving image recording circuit 509 to record moving image information on the recording medium.

  When the photographer operates the still image trigger switch 504 while the moving image is being captured or is not being recorded, but is displayed on the electronic viewfinder 506, the CPU 232 drives the still image recording circuit 507. Then, still image information is recorded on the recording medium.

  At this time, if the still image recording resolution is set by the still image resolution setting switch 505 as a low resolution level equivalent to, for example, an NTSC television signal called VGA, an image of one frame being recorded is recorded as it is. Recorded on the medium.

  Note that moving image recording can be performed in parallel by temporarily storing high-resolution still image information in a memory 511 provided in the still image recording circuit 507 and recording from the high-resolution still image information.

  FIG. 6 shows the configuration of a lens driving mechanism used in an optical apparatus that is Embodiment 2 of the present invention. FIG. 7 shows an enlarged part of FIG.

  In these drawings, reference numeral 11 denotes a first guide bar extending in the optical axis direction. The first guide bar 11 is engaged with a U-groove portion 13b formed in a moving ring 13 described later so as to be movable in the optical axis direction. Reference numeral 12 denotes a second guide bar extending in the optical axis direction. A sleeve portion 13a formed on the movable ring 13 is engaged with the second guide bar 12 so as to be movable in the optical axis direction.

  The moving ring 13 as a holding member holds the lens 14. The moving ring 13 is guided in the optical axis direction by the sleeve portion 13 a engaging the second guide bar 12, and the second guide bar 11 by engaging the U groove portion 13 b with the first guide bar 11. Rotation about the bar 12 is prevented.

  Two flange portions 13e and 13f separated from each other in the optical axis direction are integrally formed on the moving ring 13. The flange portion 13e is formed with a hole portion 13c into which the shaft portion 15a formed at one end in the optical axis direction of the first rack member 15 as the first member is inserted. Further, the flange portion 13f is formed with a hole portion 13d into which a shaft portion 16b (see FIG. 7) formed at the other end in the optical axis direction of the second rack member 16 as the second member is inserted. .

  In FIG. 7, reference numeral 15 c denotes a plurality of rack teeth (tooth portions) formed on the first rack member 5. The rack teeth 15c are inclined by an angle θ with respect to a direction orthogonal to the direction of the axis A (that is, the optical axis direction) of the feed screw 18a described later. This angle θ is equal to the lead angle of the feed screw 18a. However, “equal” here means not only when they are completely equal, but also when they differ within a range that can be regarded as equal (for example, an allowable error range), as in the first embodiment.

  The second rack member 16 has one rack tooth (tooth portion) 16c inclined by an angle θ with respect to a direction orthogonal to the axis A direction of the feed screw 18a. This angle θ is also equal to the lead angle of the feed screw 18a, similarly to the first rack teeth 15c.

  As shown in FIG. 7, the second rack member 16 has the first rack teeth 16c facing the rack teeth 15c of the first rack member 15 (hereinafter, this state is referred to as a rack assembled state). It is attached to the rack member 15. Specifically, the second rack member 16 has a shaft portion 16b that is inserted into the hollow shaft portion 15b of the second rack member 16 in the axial direction. That is, the first rack member 15 and the second rack member 16 are assembled so as to be capable of relative movement in the axial direction in a so-called nested manner.

  In the rack assembled state, the rack teeth 15c formed on the first rack member 15 and the rack teeth 16c formed on the second rack member 16 have an angle θ opposite to the direction orthogonal to the direction of the axis A. Just leaning. That is, as shown in FIG. 7, when the clockwise direction is +, the rack teeth 15c are inclined by + θ and the rack teeth 16c are inclined by −θ with respect to the direction orthogonal to the axis A direction.

  The first rack member 15 has a truncated cone portion 15h at the proximal end portion of the shaft portion 15a. Further, the base end side portion of the shaft portion 16b of the second rack member 16 has a trapezoidal plate portion 16h having both sides sandwiching the central axis in a truncated cone shape as shown in FIG.

  And the coil part of the torsion coil spring 17 which is an urging member (elastic member) is arrange | positioned in the compression state on the outer periphery of the hollow shaft part 15b. Thereby, the spring force generated in the coil portion of the torsion coil spring 17 acts so as to separate the first and second rack members 15 and 16 from each other in the axial direction.

  Further, the first arm portion 17 a of the torsion coil spring 17 is locked to the first rack member 15. Further, the second arm portion 17 b of the torsion coil spring 17 is locked to the second rack member 16. As a result, the second rack member 16 is biased around the hollow shaft portion 15 b in a direction in which the rack teeth 16 c approach the rack teeth 15 c of the first rack member 15.

  A feed screw 18a is disposed between the rack teeth 15c, 16c of the first and second rack members 15, 16. Both rack teeth 15c, 16c sandwich the feed screw 18a from both sides in the radial direction by the biasing force from the arm portions 17a, 17b of the torsion coil spring 17 described above.

  In FIG. 6, 19 is a motor and 18 is its output shaft. A feed screw 18 a is formed on the output shaft 18. As the motor 19, various motors such as a stepping motor, a DC motor, and a vibration motor can be used.

  The first rack member 15 and the second rack member 16 are configured so that the shaft portions 15a and 16a described above are inserted into the holes 13c and 13d formed in the flange portions 13e and 13f of the movable ring 13, so that the movable ring 13 is attached so as to be rotatable around the shaft portions 15a and 16a. The flange portion 13f is formed with a slit connected to the hole portion 13d, and the shaft portion 16a is inserted into the hole portion 13d through the slit. These first and second rack members 15 and 16 form one rack.

  At this time, the coil portion of the torsion coil spring 17 is compressed between the first rack member 15 and the second rack member 16 as described above, and the spring force is applied to the first and second rack members. 15 and 16 are separated from each other in the axial direction. Thereby, the truncated cone part 15h and the trapezoidal plate part 16h of the first and second rack members 15 and 16 come into contact with the periphery of the hole parts 13c and 13d in the flange parts 13e and 13f, and the shaft part with respect to the hole parts 13c and 13d. Axis misalignment of 15a and 16a is avoided. At the same time, play in the direction of the axis A relative to the moving ring 13 of the first and second rack members 15 and 16 can be removed. Therefore, the position of the moving ring 13 can be controlled with high accuracy by the driving force from the feed screw 18a.

  In the lens driving mechanism configured as described above, when the motor 19 is energized and the output shaft 18 is rotated, the first rack member 15 is driven in the axial direction A by the engagement of the feed screw 18a and the rack teeth 15c. Force is generated. Further, a driving force in the axial direction A is also generated in the second rack member 16 by the meshing of the feed screw 18a and the rack teeth 16c. These driving forces are transmitted to the moving ring 13 to move the moving ring 13 in the optical axis direction.

  At this time, as described above, the rack teeth 15c and 16c are inclined in directions opposite to each other and the inclination angle θ is equal to the lead angle of the feed screw 18a, so that the gap between the feed screw 18a and the rack teeth 15c and 16c is There is almost no twisting.

  In this embodiment, since the relative movement of the first and second rack members 15 and 16 in the direction of the axis A is allowed, both rack teeth 15c and 16c are shifted in pitch with respect to the feed screw 18a. Can be engaged without any problems.

  With the above configuration, it is possible to suppress an increase in driving resistance due to twisting and pitch deviation in the lens driving mechanism that drives the moving ring 13 in the optical axis direction.

  The shapes of the feed screw 18a and the rack teeth 15c and 16c are as described in the first embodiment (FIG. 4). However, the feed screw 18a may have a general rolling screw shape.

  In addition, the lens driving mechanism of this embodiment can be used for the optical apparatus described in Embodiment 1 (FIG. 5).

  As described above, according to each of the above-described embodiments, two rack members are combined into one rack so that they face each other so as to sandwich the lead screw and are opposite to each other so as to match the lead angle of the lead screw. A rack having rack teeth inclined in the direction can be easily manufactured. By using this rack, it is possible to suppress the occurrence of twisting and an increase in driving resistance between the rack and the feed screw when the moving ring (lens) is driven.

  Further, since both rack teeth properly mesh with the feed screw in a state where the pitch deviation between both rack teeth and the feed screw is automatically corrected, an increase in driving resistance due to the pitch deviation can be avoided. As a result, for the actuator that drives the feed screw, it is not necessary to set the torque in consideration of an increase in driving resistance, so that a small and high-speed actuator can be used. As a result, it is possible to reduce the size of the optical device, reduce power consumption, and reduce noise, and also to increase the speed of zooming and focusing operations.

  In addition, since the threaded portion is provided on the radially inner side of the feed screw and the protrusion is provided on the outside to prevent tooth skipping, the rack can be driven smoothly near the root of the feed screw, and the lens position caused by vibration or impact can be adjusted. Variations can be avoided.

  In addition, this invention is not restricted to the structure demonstrated in the said Example, A various change and deformation | transformation are possible for this Example in the range shown to a claim.

1 is a perspective view illustrating a configuration of a lens driving mechanism that is Embodiment 1 of the present invention. FIG. The figure which expanded a part of FIG. FIG. 2 is an enlarged view of a part of FIG. 1. Sectional drawing of the feed screw used in Example 1. FIG. FIG. 3 is a block diagram of an optical apparatus provided with the lens driving mechanism of Examples 1 and 2. FIG. 6 is a perspective view illustrating a configuration of a lens driving mechanism that is Embodiment 2 of the present invention. The figure which expanded a part of FIG.

Explanation of symbols

1, 2, 11, 12 Guide bar 3, 13 Moving ring 4, 14 Lens 5, 15 First rack member 6, 16 Second rack member 5c, 6a, 15c, 16c Rack teeth 7, 17 Torsion coil spring 8a , 18a Lead screw 9, 19 Motor

Claims (5)

A holding member for holding the optical element;
A rack attached to the holding member;
A feed screw that drives the holding member by meshing with the rack and rotating;
Each of the racks includes a first member having a tooth portion that meshes with the feed screw and a second member that is a member different from the first member,
The tooth portions of the first and second members are disposed on opposite sides of the feed screw and are inclined in directions opposite to each other with respect to a direction orthogonal to the axial direction of the feed screw. Features optical equipment.   2. The optical apparatus according to claim 1, wherein the tooth portions of the first and second members each have an inclination angle equal to a lead angle of the feed screw with respect to a direction orthogonal to the axial direction. 3. The optical device according to claim 1, wherein the feed screw has a screw portion that meshes with the tooth portion and a protrusion provided on an outer periphery of the screw portion, and satisfies the following condition. machine.
θ3 ≦ θ2 <θ1
The optical apparatus according to claim 1, wherein θ1 is an apex angle of the threaded portion, θ2 is an apex angle of the protruding portion, and θ3 is an apex angle of the tooth portion.   The optical apparatus according to any one of claims 1 to 3, wherein the first and second members are assembled so as to be relatively movable in the axial direction. Each of the first and second members has an attachment portion that is attached to the holding member so as to be movable in the axial direction.
An urging member is provided between the first member and the second member to urge each of the attachment portions toward opposite sides in the axial direction to press the holding member. Item 5. The optical apparatus according to any one of Items 1 to 4.