JP2006178361A - Optical apparatus and camera module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical apparatus capable of preventing the deterioration in lens performance due to a fitting backlash. <P>SOLUTION: A zoom lens unit 10 is provided with: a second lens group 122; a first guide shaft 131 which extends in parallel to the optical axis of the second lens group 122; a frame 16 for moving first lens which has a holding section 161 holding the second lens group 122, and a section 164 to be guided by the first guide shaft 131, a first auxiliary movable body 21 which is guided by the first guide shaft 131 and is rotatable around the first guide shaft 131 with respect to the frame 16 for moving first lens and is movable in the optical axis direction integrally with the frame 16 for moving first lens, and an energizing means which is arranged between the first auxiliary movable body 21 and the frame 16 for moving first lens and energizes the frame 16 for moving first lens in the prescribed direction around the first guide shaft 131 with respect to the first auxiliary movable body 21. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical device and a camera module that advance or retract one or more lens groups in the optical axis direction.

A technique is known in which a guide shaft extending parallel to the optical axis is provided on the side of a lens holding frame that holds the lens, the lens holding frame is guided by the guide shaft, and the lens is moved in the optical axis direction. In such a technique, there has been proposed one provided with a spring for urging the lens holding frame in the optical axis direction (for example, cited documents 1 and 2). In Cited Documents 1 and 2, the lens moving frame is driven in the optical axis direction by a feed screw inserted through the lens holding frame.
JP-A-4-342211 JP-A-7-151947

  There is a gap, a so-called fitting play, between the guide shaft and the engagement hole portion of the guide. The fitting backlash is caused, for example, by variations in processing accuracy during manufacture of the guide shaft and guide. Then, when the optical axis of the lens shifts due to the fitting backlash, image shake and parallax shift occur. However, the cited document 1 does not disclose a technique for preventing an image shake caused by the fitting play. Although the technique of the cited document 2 aims at preventing the vibration during the lens movement caused by the fitting play, the optical axis shift itself, for example, the optical axis between a plurality of lenses arranged on the same axis. The gap cannot be eliminated.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an optical device and a camera module capable of preventing lens performance deterioration caused by fitting backlash.

  The optical device of the present invention includes a lens group, a guide shaft extending in parallel with the optical axis of the lens group, a holding unit that holds the lens group, and a guided portion that is guided by the guide shaft. An auxiliary moving body guided by the guide shaft, rotatable about the guide axis with respect to the lens moving body, and movable in the optical axis direction integrally with the lens moving body, and the auxiliary moving body And an urging means for urging the lens moving body in a predetermined direction around the guide shaft with respect to the auxiliary moving body.

  Preferably, the guided portion has a inserted portion through which the guide shaft is inserted or a holding portion for holding the guide shaft, and the auxiliary moving body is inserted through the guide shaft or the guide. It has a clamping part that clamps the shaft.

  Preferably, a cam device including a rotating body provided in parallel to the guide shaft and rotatable about an axis parallel to the optical axis, and a cam portion provided in a spiral shape on an outer surface of the rotating body. The auxiliary moving body further includes a locked portion that is locked to the cam portion and is guided in the optical axis direction by the cam portion as the rotating body rotates.

  Preferably, the urging means is a torsion spring having a coil portion in which a wire is wound spirally and arm portions extending from both ends of the wire, and the torsion spring is attached to the coil portion. A guide shaft is inserted and slidably provided on the guide shaft. One of the arm portions engages with the lens moving body, and the other arm portion engages with the auxiliary moving body to perform the auxiliary movement. The lens moving body is biased with respect to the body in a predetermined direction around the guide shaft.

  Preferably, the auxiliary moving body has at least two bearing portions provided at a predetermined interval in the guide axis direction, and the guided portion and the coil portion are interposed between the two bearing portions. Has been placed.

  Preferably, in the torsion spring, one end of the coil portion is in contact with the lens moving body, the other end is in contact with the auxiliary moving body, and the lens moving body is moved in the guide axial direction with respect to the auxiliary moving body. Also energize.

  The lens module according to the present invention includes a lens group, a guide shaft extending in parallel with the optical axis of the lens group, a holding portion that holds the lens group, and a guided portion that is guided by the guide shaft. An auxiliary moving body guided by the guide shaft, rotatable about the guide axis with respect to the lens moving body, and movable in the optical axis direction integrally with the lens moving body, and the auxiliary moving body And an urging means for urging the lens moving body in a predetermined direction around the guide shaft with respect to the auxiliary moving body.

  The camera module of the present invention may include various preferable modes in the above-described optical device of the present invention.

  According to the present invention, it is possible to prevent lens performance deterioration caused by fitting backlash.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is an external perspective view of a zoom lens unit to which an optical device and a camera module of the present invention are applied as viewed from the front side, and FIG. 2 is a partially omitted view of the zoom lens unit according to the present invention as viewed from the back side. FIG. 3 is an external perspective view, FIG. 3 is a front view of the zoom lens unit according to the present invention, and FIG. 4 is a top view of the zoom lens unit according to the present invention.

  As shown in the figure, the zoom lens unit 10 includes a fixed frame 11 that houses main components such as a lens, a guide shaft, and a cam device, a first lens group 121, a second lens group 122, and a third lens. The first lens group 121 is fixed to the fixed frame 11, and the second and third lens groups 122 and 123 are arranged in the fixed frame 11 so as to be movable on the optical axis. An imaging optical system 12, and a guide unit 13 having a first guide shaft 131 and a second guide shaft 132 for guiding the second lens group 122 and the third lens group 123 of the imaging optical system 12 in a direction parallel to the optical axis; A cam device 14 arranged in parallel in the fixed frame 11 with respect to the imaging optical system 12 and an imaging element 151 made up of a CCD or CMOS sensor are arranged so as to include an optical axis as a part of the imaging optical system 12. Have .

  1 and 2, the optical axis of the imaging optical system 12 is configured to be in the Z-axis direction of the orthogonal coordinate system set in the drawing, and as described in detail later, the second lens The group 122 and the third lens group 123 move (advance and retreat) in the optical axis direction according to the rotation of the cam device 14.

For example, in FIG. 1 and FIG. 2, the front side, the rear side, and the lower side of the fixed frame 11 are open, and the lower sides of the left and right sides are attached to the base 15. And the one end part of the 1st guide shaft 131 of the guide part 13 and the 2nd guide shaft 132 is pivotally supported in the position which opposes at about 180 degrees.
On the left side of the upper surface portion 11a of the fixed frame 11, a first opening 111a having a circular cross section communicating with the optical axis direction is formed to fix the first lens group 121 of the imaging optical system 12. A lens group fixing frame 111 is provided.
Further, in parallel with the first lens group fixed frame 111, a bearing portion of a rotating shaft of a rotating body of the cam device 14, a gear train for transmitting a rotational driving force of a motor (not shown) to the rotating body with a predetermined reduction ratio, and the like. Is integrally formed.

5 is a cross-sectional view in the direction of arrows AA in FIG. 4, and FIG. 6 is a cross-sectional view in the direction of arrows BB in FIG.
Hereinafter, a specific configuration example of the imaging optical system 12 according to the present embodiment will be described in association with FIGS. 5 and 6 in addition to FIGS.

As shown in FIGS. 5 and 6, the imaging optical system according to the present embodiment includes a first lens group 121 having a negative refractive power, arranged in order from the object side OBJS, and a positive and negative refraction. A second lens group 122 having a positive refracting power as a whole, a third lens group 123 having a single refracting power, a third lens group 123 having a negative refracting power, an imaging unit 124 provided on the base side, and The aperture portion 125 is disposed on the object side (the first lens group 121 side) of the second lens group 122.
When zooming is performed in the imaging optical system 12, among the first lens group 121, the second lens group 122, and the third lens group 123, the second lens group 122 and the third lens group 123 are on the optical axis. Is moved according to the rotation of the cam device 14.

  As described above, in the present embodiment, the imaging optical system 12 includes one first lens group 121, three second lens groups 122, and one third lens group 123 arranged in order from the object side OBJS. It consists of a total of five lenses.

The first lens group 121 includes, for example, a meniscus lens 1211 having a negative refractive power and having a convex surface on the object side on the first surface.
In this way, by configuring the first lens group 121 with the meniscus lens 1211 having negative refractive power, it becomes easy to suppress distortion.

Since the second lens group 122 is the only group having positive refractive power, a three-lens configuration is adopted to correct various aberrations. Further, when this second lens group 122 glass lens is used, it is smaller and therefore more expensive than a normal lens. Therefore, in order to achieve cost reduction, the three lenses constituting the second lens group 122 are made of plastic lenses.
The three plastic lenses constituting the second lens group 122 include, for example, a positive meniscus lens 1221, a negative meniscus lens 1222, and a positive biconvex lens 1223 from the first lens group 121 side (object side). Is done.
The positive meniscus lens 1221 performs spherical aberration correction satisfactorily, and the lens located at the center of the three lenses is the negative meniscus lens 1222, while suppressing overcorrection of the ellipsoidal curvature generated in the positive lens. By suppressing the occurrence of coma aberration, the performance balance is achieved. By these, aberration fluctuations associated with zooming are suppressed, and high-performance zooming is possible.

Since the third lens group 123 has a single lens configuration, various aberrations need to be corrected here, spherical aberration, coma aberration, astigmatism, distortion correction, and correction of the exit angle at the wide angle end are performed. It is also necessary for.
The third lens group 123 includes a negative lens 1231 having a concave surface on the image surface side, for example.
In the present embodiment, focus adjustment (focus adjustment) is performed by the third lens group 123 and moves from the infinity toward the imaging surface side.
When the third lens group is a positive lens, the distance between the second lens group and the third lens group at the telephoto end must be ensured in order to move toward the object side.
In the present embodiment, since it moves to the image plane side, the distance between the second lens group 122 and the third lens group 123 at the telephoto end can be reduced.
This is one of the factors that make it possible to reduce the size of the variable magnification optical system, and if it is the same size, it is possible to arrange the power without difficulty, enabling higher performance and lowering the eccentricity sensitivity. Yes.

In the imaging unit 124 provided on the base 15 side, a parallel plane plate (cover glass) 152 made of glass and an imaging element 151 made of, for example, a CCD or a CMOS sensor are sequentially arranged from the third lens group 123 side. .
Light from the subject (object) via the imaging optical system is imaged on the imaging surface 151 a of the imaging element 151.

  The imaging optical system having the first lens group 121, the second lens group 122, and the third lens group 123 described above has a telephoto function because the entire optical system has negative, positive, and negative lens configurations. Therefore, the overall length can be shortened.

  The imaging optical system 12 according to the present embodiment having the above-described configuration is downsized so that it can be mounted on a mobile phone or the like.

As described above, the first lens group 121 of the imaging optical system 12 is fixed to the first lens fixed frame 111, and the second lens group 122 is housed and fixed to the first lens moving frame 16, and the third lens. The group 123 is housed and fixed in the second lens moving frame 17.
The first lens moving frame body 16 and the second lens moving frame body 17 are configured such that the first guide shaft 131 and the second guide shaft 132 are guided in the optical axis direction.

  Next, the configurations of the first lens moving frame body 16 and the second lens moving frame body 17 and the arrangement and engagement relationship between the first guide shaft 131, the second guide shaft 132, and the cam device 14 will be described.

  FIG. 7 is a perspective view showing the arrangement and engagement relationships of the first lens moving frame body 16 and the second lens moving frame body 17, the first guide shaft 131, the second guide shaft 132, and the cam device 14 from the front side. FIG. 8 shows the arrangement and engagement relationship between the first lens moving frame body 16 and the second lens moving frame body 17, the first guide shaft 131, the second guide shaft 132, and the cam device 14 from the back side. FIG. 9 is a perspective view showing the arrangement and engagement relationship between the first lens moving frame body 16 and the second lens moving frame body 17, the first guide shaft 131, the second guide shaft 132, and the cam device 14. It is a perspective view shown from the upper surface side.

  In the present embodiment, the first guide shaft 131 is pivotally supported on the fixed frame body 11 so as to be slightly on the front side in the vicinity of the cam device 14, and the second guide shaft 132 includes the first and second guide shafts 132. The lens moving frames 16 and 17 are sandwiched between and are opposed to each other at approximately 180 ° and are pivotally supported by the fixed frame 11 so as to be located slightly on the back side.

The first lens moving frame 16 includes a first frame 161 on the first lens group 121 side that is substantially integrally formed of plastic or the like in order to accommodate and fix the second lens group 122 including three lenses. The second frame 162 on the third lens group 123 side has a two-stage configuration.
The first lens moving frame body 16 extends in a direction substantially orthogonal to the optical axis from the back side of the first frame body 161 and has a plate shape that is locked to the first cam section 1421 of the cam device 14. The to-be-latched part 163 is formed.
The first lens moving frame body 16 is inserted into and supported by the first guide shaft 131 substantially integrally with the front surface side of the first locked portion 163, and the first guide shaft is rotated according to the rotation of the cam device 14. A first guided portion 164 (see FIG. 5) for guiding 131 is formed.
Further, the first lens moving frame 16 is positioned at a predetermined position of the second frame 162, specifically, at a position facing the formation position of the first locked portion 163 at approximately 180 ° with respect to the second guide shaft. A third guided portion 165 is formed which is inserted into the shaft 132 from the side portion of the shaft and is engaged by being sandwiched so that the second guide shaft 132 is guided according to the rotation of the cam device 14.

The second lens moving frame 17 is formed in a one-stage configuration with plastic or the like in order to accommodate and fix the first lens group 123 composed of one lens.
The second lens moving frame 17 extends in a direction substantially orthogonal to the optical axis from the back side, and has a plate-like second locked portion 171 that is locked to the second cam portion 1422 of the cam device 14. Is formed.
The second lens moving frame 17 is inserted into and supported by the first guide shaft 131 integrally with the front surface side of the second locked portion 171, and the first guide shaft 131 is rotated according to the rotation of the cam device 14. A second guided portion 172 (see FIG. 5) is formed.
Further, the second lens moving frame body 17 is inserted into the second guide shaft 132 from the side of the shaft at a position facing the formation position of the first locked portion 171 at approximately 180 ° and sandwiched. A fourth guided portion 173 is formed that engages and guides the second guide shaft 132 according to the rotation of the cam device 14.

  In the present embodiment, the first lens moving frame 16 and the second lens moving frame 17 are opposed to the formation positions of the substantially first locked portion 163 and the second locked portion 171 on the front side. Coil spring as an elastic body between the first lens moving frame body 16 and the second lens moving frame body 17 so that the first lens moving frame body 16 and the second lens moving frame body 17 can be stably offset at a position where 18 is suspended.

  In the present embodiment, the first auxiliary moving body as the auxiliary moving body is used to reduce the fitting play by urging the first lens moving frame body 16 and the second lens moving frame body 17 around the first guide shaft 131. A body 21 and a second auxiliary moving body 22 are provided.

The first auxiliary moving body 21 includes a first bearing portion 211 and a second bearing portion 212 that are formed at a predetermined interval in the optical axis direction.
Similarly, the second auxiliary moving body 22 includes a third bearing portion 221 and a fourth bearing portion 222 that are formed at a predetermined interval in the optical axis direction.
The first bearing portion 211, the second bearing portion 212, the third bearing portion 221, and the fourth bearing portion 222 are spaced from the first guide shaft 131 by a predetermined distance, and the first bearing portion 211. The third bearing portion 221, the second bearing portion 212, and the fourth bearing portion 222 are inserted in this order.

FIG. 10 is an exploded perspective view of the first bearing portion 211 of the first guide shaft 131, the first lens moving frame body 16, and the first auxiliary moving body 21.
The first bearing portion 211 is formed in a shape in which a substantially cylindrical side surface is notched, and holes 2113 and 2114 through which the first guide shaft 131 is inserted are provided in the end surfaces 2111 and 2112, respectively. In addition, inside the first bearing portion 211, a guided portion 164 of the lens moving frame body 16 and a torsion spring 23 in which a wire is spirally wound are housed from an opening 2115 in which a side surface of the cylinder is cut out. The first guide shaft 131 is inserted through the hole 1642 of the lens moving frame 16 and the coil 231 of the torsion spring 23. That is, the first lens moving frame body 16 and the first bearing portion 211 of the first auxiliary moving body 21 are both guided by the first guide shaft 131 and inserted through the first guide shaft 131 so as to be rotatable relative to each other. However, the range of rotational movement is restricted by the guided portion 164 and the opening 2115.

FIG. 11A is a cross-sectional view in the direction of the arrow F-F in FIG. 10, and FIG. 11B shows the first bearing portion 211 and the torsion spring 23 in FIG. It is sectional drawing.
Of the arm portions extending linearly from the end of the wire rod of the torsion spring 23, one arm portion 233 is locked to protrude from the guided portion 164 of the first lens moving frame 16 toward the first guide shaft 131. The other arm portion 232 is engaged with one edge portion (locked portion) 2116 of the opening 2115 of the first bearing portion 211 of the auxiliary moving body 21. As a result, the guided portion 164 is biased by the torsion spring 23 in the direction around the first guide shaft 131 by the torsion spring 23 as indicated by the arrow y1.

  The first lens moving frame 16 is inserted through the first guide shaft 131 and the second guide shaft 132, and is supported so as not to rotate macroscopically. However, it will rotate microscopically due to the backlash. However, as described above, the torsion spring 23 biases the first guide shaft 131 around the first guide shaft 131 in a certain direction, so that microscopic rotation is suppressed, and deterioration of lens performance based on the fitting play is suppressed.

It can also be considered as shown in FIG. Due to the biasing force of the torsion spring 23, the other edge 2117 of the opening 2115 and the lens moving frame body 16 abut. That is, the lens moving frame body 16 and the first bearing portion 211 are fixed to each other in the rotational direction around the first guide shaft 131. Therefore, the torsion spring 23 biases the first bearing portion 211 and the guided portion 164 in the direction perpendicular to the first guide shaft 131 indicated by the arrow y3 by the both arm portions 232 and 233 with the first guide shaft 131 as a fulcrum. is doing. As a result, the first guide shaft 131 always slides in contact with the hole 1642 of the guided portion 164 in the same direction, thereby preventing image shake and optical axis deviation.
The urging direction indicated by the arrow y3 is a direction in which the locked portion 163 is pressed against the rotating body 141, and the locked portion 163 and the cam portion 142 are more firmly engaged.

The guided portion 172 of the second lens moving frame 17 and the fourth bearing portion 222 of the second auxiliary moving body 22 are also the guided portion 164 of the first lens moving frame 16 and the first bearing portion of the first auxiliary moving body 21. The configuration is the same as that of 211.
The position of the engaged portion of the second lens moving frame 17 and the size and direction of the opening of the second auxiliary moving body 22 are the position of the engaged portion 1641 of the first lens moving frame 16, It is desirable that the size and orientation of the opening 2115 of the first auxiliary moving body 21 be the same. Thereby, the urging directions in the direction orthogonal to the first guide shaft 131 of the second lens moving frame body 17 and the first lens moving frame body 16 are set to the same direction, and the second lens group 122 and the third lens group 123 are set. It is possible to suppress the deviation of the optical axis.

  As shown in FIG. 5, the guided portion 164 is twisted closer to the second lens moving frame 17 than the torsion spring in the first lens moving frame 16, and the guided portion 172 is twisted in the second lens moving frame 17. It is arranged closer to the first lens moving frame 17 than the spring. However, conversely, the torsion spring in the first lens moving frame 16 may be located closer to the second lens moving frame 17 than the guided portion 164.

  Next, the cam apparatus 14 in this embodiment is demonstrated.

  12 and 13 are partially cutaway perspective views showing a state in which the cam device according to the present embodiment is pivoted on the fixed frame body, and FIG. 14 is an overall sectional structure of the cam device according to the present embodiment. FIG. 15 is a cross-sectional view of the axial center portion of the cam device according to the present embodiment.

As shown in FIG. 8 and the like, the cam device 14 includes a rotating body 141 that can rotate about a rotating shaft 1411 that is substantially parallel to the first guide shaft 131 and the second guide shaft 132, and an outer surface of the rotating body 141. Thus, the first locking portion 163 of the first lens moving frame 16 is locked, and the first locked portion is rotated according to the rotation. A first cam portion 1421 that guides 163, and a second locked portion of the second lens moving frame 17 that is formed to rotate along the outer surface of the rotating body 141 in accordance with the rotation of the rotating body 141. A belt-like body 142 is formed, which includes a second cam portion 1422 that is engaged with the second engaged portion 171 in accordance with rotation.
The belt-like body 142 has a first surface 142a and a second surface 142b facing each other in the optical axis direction, the first surface 142a functions as the first cam portion 1421, and the second surface 142b is the second cam portion 1422. Function as.

That is, as shown in FIG. 8, the band-like body 142 has a slope from the rear end side toward the front end portion and is formed in a spiral shape, and the front end side is the first surface 142 a and the rear end portion. The side constitutes the second surface 142b.
The width of the belt-like body 142 is such that the first locked portion 163 formed on the first lens moving body 16 and the second locked portion 171 formed on the second lens moving frame 17 are in the optical axis direction. Is set to be substantially equal to the interval of.
With such a configuration, the first lens moving frame 16 and the second lens moving frame 17 are biased by the coil spring 18, so that the first lens moving body 16 formed on the first lens moving body 16 has the first structure. The second surface 171 formed on the locking portion 163 and the second lens moving frame 17 sandwiches the first surface 142a and the second surface 142b of the belt-like body 142, and the first surface 142a The second surface 142b, that is, the first cam portion 1421 and the second cam portion 1422 can be stably held.
Therefore, the first locked portion 163 formed on the first lens moving body 16 and the second locked portion 171 formed on the second lens moving frame 17 are connected to the first surface 142a of the belt-shaped body 142. The second surface 142b need not be fixed with screws or the like, and the assembly itself is simple.

  The first surface 142a and the second surface 142b of the belt-shaped body 142 forming the slope are the first locked portions 163 guided by the first surface 142a and the second surface 142b (first cam portion or second cam portion). And steps corresponding to the functions of the second lens group 122 and the third lens group 123 housed in the first lens moving frame 16 and the second lens moving frame 17 in which the second locked portion 171 is formed, respectively. Is formed.

Further, as shown in FIGS. 12 and 13, the cam device 14 is provided with a gear 1412 that rotates at the distal end under the rotational force of a motor (not shown).
For example, as shown in FIG. 12, the gear 1412 is engaged with a gear train 19 that transmits a rotational driving force of a motor (not shown) with a predetermined reduction ratio.

  In the cam device 14, in order to obtain the positional accuracy of the first lens moving frame body 16 and the second lens moving frame body 17 to be driven, as shown in FIGS. The front end portion 1411a and the rear end portion 1411b of the shaft 1411 are supported by the front end bearing portion 143 and the rear end bearing portion 144, respectively, and the front end portion 1411a is given a predetermined force by a coil spring 145 as an urging means. It is biased toward the tip bearing portion 143 with a force and is offset.

In the present embodiment, the front end portion 1411a and the rear end portion 1411b of the rotating shaft 1411 are formed so as to be in substantially point contact with the front end portion bearing portion 143 and the rear end bearing portion 144.
Specifically, at the central portion of the rotating shaft 1411, one end portion of the biasing coil spring 145 as an urging means abuts against the inner wall of the rotating shaft 1411 on the front end portion 1411 a side, and the coil spring 145 and the rear end bearing portion 144. An intermediate body 146 that is substantially point-contacted with the rear end bearing portion 144 is disposed between the two.
The intermediate body 146 has a substantially spherical shape at least on the side in contact with the rear end bearing portion 144, and is configured to realize point contact. In the present embodiment, a sphere is used as the intermediate 146.

In the cam device 14 having such a configuration, the rotating body 141 is rotationally driven by a motor (not shown), and the first locked portion 163 and the second locked portion 171 are the first surface 142a of the belt-like body 142 and The second surface 142b is stably guided.
In this case, the rotating body 141 is biased toward the tip end bearing portion 143 with a predetermined biasing force by the coil spring 145 as the biasing means, and the tip portion 1411a of the rotating shaft 1411 is biased. The positional accuracy of the first lens moving frame body 16 and the second lens moving frame body 17 that are the driving targets can be kept high, and high-precision lens driving is realized.

As described above, according to the present embodiment, the imaging optical system is a variable power lens having a three-group configuration. The first lens group 121 has one lens, the second lens group 122 has three, Since the three lens groups 123 are configured as a single lens and all the second lens groups 122 are made of plastic, the total length of the optical system can be shortened. The diameter of the lens can be reduced, and the cost can be reduced.
In the aberration correction, the lens arrangement is optimized by optimizing the power arrangement of each lens group. Further, the lens arrangement is further reduced by appropriately arranging aspheric surfaces in the second lens group 122 and the third lens group 123. realizable. By optimizing these conditions, there is an advantage that the distortion can be further reduced with high performance in spite of a compact variable power lens.
Further, in the present embodiment, the focus adjustment is performed by the third lens group 123 and moves toward the imaging surface side from the infinity to the closest position, so that the second lens group 122 and the third lens group 123 at the telephoto end are The distance can be reduced. As a result, the variable magnification optical system can be made compact, and if it is the same size, it is possible to arrange the power without difficulty, and it is possible to achieve higher performance and lower decentration sensitivity.

  In addition, since the three plastic second lens groups 122 have a positive meniscus lens, a negative meniscus lens, and a positive biconvex lens configuration, the positive meniscus lens can satisfactorily correct spherical aberration, In a negative meniscus lens, it is possible to suppress overcorrection of curvature of field that occurs in the positive lens, and to suppress the occurrence of coma aberration in parallel with this. Accordingly, it is possible to balance the performance, and there is an advantage that high-performance zooming is possible by suppressing aberration fluctuations accompanying zooming.

  In addition, in the relationship between the focal lengths (fl, f2, f3) of each lens unit and the focal length fw at the wide-angle end where the combined power is strong, by taking the power balance of each lens unit, high-performance and compact zooming A lens can be realized.

  By defining the condition of the exit pupil position with respect to the restriction of the incident angle to the image sensor 151 as a desired condition, it is possible to relax the restriction of the exit pupil while being wide-angle and compact.

  In the cam device 14, the rotating body 141 is rotationally driven by a motor (not shown), and the first locked portion 163 and the second locked portion 171 stabilize the first surface 142 a and the second surface 142 b of the strip-shaped body 142. In the rotating body 141, the rotating shaft 1411 has its tip portion 1411a biased toward the tip portion bearing portion 143 with a predetermined biasing force by a coil spring 145 as biasing means. Therefore, it is possible to keep the positional accuracy of the first lens moving frame body 16 and the second lens moving frame body 17 to be driven high, and there is an advantage that high-precision lens driving can be realized.

  As described above, according to the present embodiment, it is possible to provide a zoom lens unit that can realize downsizing, hardly cause an eccentricity error and an inclination error, can move the lens smoothly, and can realize stable position adjustment. it can.

(Second Embodiment)
17 is a perspective view showing a finder device to which the optical device and the camera module of the present invention are applied, FIG. 18A is a cross-sectional view in the direction of arrows HH in FIG. 17, and FIG. It is sectional drawing in the GG arrow direction of FIG.
The viewfinder device 30 has a three-group configuration of a first lens group 321, a second lens group 322, and a third lens 323, and the first lens group 321 is fixed to a fixed frame body (not shown), and the fixed frame body. On the other hand, the finder optical system 32 in which the second and third lens groups 322 and 323 are arranged to be movable on the optical axis, and the second lens group 322 and the third lens group 323 of the finder optical system 32 are used as the optical axis. A guide portion 33 having a first guide shaft 331 for guiding in a parallel direction and a cam device 34 arranged in parallel to the finder optical system 32 are provided. The guide unit 33 also includes a second guide shaft (not shown) provided at a position facing the first guide shaft 331 across the optical system 32.

  When zooming is performed in the finder optical system 32, the second lens group 322 and the third lens group 323 out of the first lens group 321, the second lens group 322, and the third lens group 323 are on the optical axis. It moves according to the rotation of the cam device 34. The configuration of the cam device 34 is the same as that of the cam device 14 of the first embodiment.

  Each lens group 321, 322, 323 of the finder optical system 32 is configured by a single lens. The second lens group 322 is housed and fixed in the first lens moving frame body 36, and the third lens group 323 is housed and fixed in the second lens moving frame body 37. The moving frame bodies 36 and 27 have guide portions 362 and 372 guided by the first guide shaft 331, respectively.

Further, a first auxiliary moving body 38 and a second auxiliary moving body 39 are provided corresponding to the first lens moving frame body 36 and the second lens moving frame body 37.
The first auxiliary moving body 38 includes a bearing portion 381 having a substantially cylindrical side surface cut out, and a locked portion 382 that is locked to the first cam portion 3421 of the cam device 34. The body 39 includes a bearing portion 391 in which a substantially cylindrical side surface is cut out, and a locked portion (not shown) locked to the second cam portion 3422 of the cam device 34.

  Note that the first auxiliary moving body 38 and the second auxiliary moving body 39 are brought close to each other in order to lock the locked portions of the first auxiliary moving body 38 and the second auxiliary moving body 39 to the cam portion 342, respectively. A tension spring (not shown) that is biased to the center is provided. Note that the tension spring can be replaced with a tension spring that moves the first lens moving frame 36 and the second lens moving frame 37 close to each other.

The mounting structure of the guided portion 362 of the first lens moving frame body 36, the bearing portion 381 of the first auxiliary moving body 38, and the first guide shaft 331 is guided by the first lens moving frame body 16 of the first embodiment. This is the same as the mounting structure of the part 164, the first bearing part 211 of the first auxiliary moving body 21, and the first guide shaft 131.
That is, the guided portion 362 and the torsion spring 40 are accommodated in the bearing portion 381, and the first guide shaft 331 is inserted into the bearing portion 381, the guided portion 362, and the torsion spring 40, and one of the torsion springs 40 is inserted. The arm portion engages with the edge of the opening portion of the bearing portion 381, and the other arm portion engages with the protruding engaged portion 3621 of the guided portion 362.

  However, as shown in FIG. 18B, the torsion spring 40 is also a compression spring, and one end of the coil portion abuts on the guided portion 362 and the other end is one of the bearing portions 381 of the first auxiliary moving body 38. The guided portion 362 is also biased in the axial direction of the first guide shaft 331 with respect to the first auxiliary moving body 38. Therefore, the first lens moving frame body 36 and the first auxiliary moving body 38 are integrated with each other in the axial direction of the first guide shaft 331 with the guided portion 362 in contact with the other end surface 3812 of the bearing portion 381. Can be moved.

On the other hand, as described above, the first auxiliary moving body 38 has the locked portion 382 that is locked to the first cam portion 3421, and the light rotates along with the rotation of the rotating body 341 of the cam device 34. Move forward and backward in the axial direction.
Accordingly, the first lens moving frame body 36 advances and retreats in the optical axis direction as the rotating body 341 rotates.

The second lens moving frame 37 and the second auxiliary moving body 39 have the same configuration as the first lens moving frame 36 and the first auxiliary moving body 38.
The position of the engaged portion of the second lens moving frame 37 and the size and direction of the opening of the second auxiliary moving body 39 are the position of the engaged portion 3621 of the first lens moving frame 36, the first It is desirable that the size and orientation of the opening of the auxiliary moving body 38 be the same. Thereby, the urging direction in the direction orthogonal to the first guide shaft 331 is set to the same direction in the second lens moving frame 37 and the first lens moving frame 36, and the second lens group 36 and the third lens group. The optical axis deviation with respect to 37 can be suppressed.
As shown in FIG. 17, the first lens moving frame 36 is biased toward the second lens moving frame 37 by the function of the torsion spring 40 as a compression spring, whereas the second lens moving frame 37 Is biased toward the first lens moving frame 36 side. However, conversely, the first lens moving frame 36 may be biased to the opposite side of the second lens moving frame 37.

In the second embodiment, the same effect as the first embodiment can be obtained.
That is, the first lens moving frame body 36 and the second lens moving frame body 37 are microscopically rotated around the first guide shaft 331 by the fitting backlash, but are rotated around the first guide shaft 331 by the torsion spring 40. The microscopic rotation is suppressed by being urged to prevent the lens performance from being deteriorated based on the fitting play. In the second embodiment, since the rotation of the auxiliary moving body is restricted by the locked portion and the rotating body 341, the lens moving frame body is also rotated by the rotating body 341 via the auxiliary moving body and the torsion spring. Be regulated. In addition, the locked portion 382 is pressed against the rotating body 341 by the biasing force of the torsion spring 40, and the cam portion 342 is firmly locked.

The present invention is not limited to the above embodiment, and may be implemented in various aspects.
The locking portion locked to the cam portion may be provided on the lens moving body as in the first embodiment, or may be provided on the auxiliary moving body as in the second embodiment.
As the urging force of the coiled torsion spring, not only the urging force by rewinding but also the urging force by tightening may be used.

It is the external appearance perspective view seen from the front side of the zoom lens unit concerning the present invention. FIG. 3 is a partially omitted external perspective view of the zoom lens unit according to the present invention as viewed from the back side. 1 is a front view of a zoom lens unit according to the present invention. It is a top view of the zoom lens unit according to the present invention. It is sectional drawing in the AA arrow direction of FIG. It is sectional drawing in the BB arrow direction of FIG. It is a perspective view which shows arrangement | positioning and engagement relation of the 1st lens moving frame body and 2nd lens moving frame body which concern on 1st Embodiment, a 1st guide shaft, a 2nd guide shaft, and a cam apparatus from the front side. . It is a perspective view which shows arrangement | positioning and engagement relation of the 1st lens moving frame body which concerns on 1st Embodiment, a 2nd lens moving frame body, a 1st guide shaft, a 2nd guide shaft, and a cam apparatus from the back side. . It is a perspective view which shows arrangement | positioning and engagement relation of the 1st lens moving frame body and 2nd lens moving frame body which concern on 1st Embodiment, a 1st guide shaft, a 2nd guide shaft, and a cam apparatus from an upper surface side. . It is a disassembled perspective view in the 1st bearing part which concerns on 1st Embodiment. It is sectional drawing of the FF line arrow direction of FIG. It is a partially cutaway perspective view showing a state in which the cam device according to the first embodiment is pivoted on the fixed frame body from the upper surface side. It is a partially cutaway perspective view showing a state in which the cam device according to the first embodiment is pivoted on the fixed frame body from the lower surface side. FIG. 3 is a perspective view showing the entire cross-sectional structure of the cam device according to the first embodiment with a part cut away. It is sectional drawing of the axial center part of the cam apparatus which concerns on 1st Embodiment. It is sectional drawing of the axial center part and drive part of the cam apparatus which concern on 1st Embodiment. The perspective view of the finder apparatus which concerns on 2nd Embodiment. It is sectional drawing which shows the principal part of the finder apparatus which concerns on 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 122 ... Lens group, 131 ... Guide shaft, 161 ... Holding part, 164 ... Guided part, 16 ... Lens moving body, 21 ... Auxiliary moving body, 23 ... Biasing means, 10 ... Optical apparatus.

Claims (7)

A lens group;
A guide shaft extending in parallel with the optical axis of the lens group;
A lens moving body having a holding portion for holding the lens group and a guided portion guided by the guide shaft;
An auxiliary moving body guided by the guide shaft, rotatable about the guide axis with respect to the lens moving body, and movable in the optical axis direction integrally with the lens moving body;
An urging unit that is disposed between the auxiliary moving body and the lens moving body and urges the lens moving body in a predetermined direction around the guide axis with respect to the auxiliary moving body;
An optical device comprising: The guided portion has a inserted portion through which the guide shaft is inserted or a holding portion that holds the guide shaft.
The optical device according to claim 1, wherein the auxiliary moving body includes an insertion portion through which the guide shaft is inserted or a holding portion that holds the guide shaft. A rotating device provided in parallel with the guide shaft and rotatable about an axis parallel to the optical axis; and a cam device provided in a spiral shape on an outer surface of the rotating body;
The optical device according to claim 1, wherein the auxiliary moving body includes a locked portion that is locked to the cam portion and that is guided in the optical axis direction by the cam portion as the rotating body rotates. . The urging means is a torsion spring having a coil portion in which a wire is wound spirally and arm portions extending from both ends of the wire,
The torsion spring is provided so that the guide shaft is inserted into the coil portion so as to be slidable on the guide shaft, one arm portion is engaged with the lens moving body, and the other arm portion is the auxiliary. The optical apparatus according to claim 1, wherein the optical apparatus is engaged with a moving body and biases the lens moving body in a predetermined direction around the guide shaft with respect to the auxiliary moving body. The auxiliary moving body has at least two bearing portions provided at a predetermined interval in the guide shaft direction,
The optical device according to claim 4, wherein the guided portion and the coil portion are disposed between the two bearing portions. In the torsion spring, one end of the coil portion abuts on the lens moving body, the other end abuts on the auxiliary moving body, and biases the lens moving body in the guide axis direction with respect to the auxiliary moving body. The optical device according to claim 5. A lens group;
A guide shaft extending in parallel with the optical axis of the lens group;
A lens moving body having a holding portion for holding the lens group and a guided portion guided by the guide shaft;
An auxiliary moving body guided by the guide shaft, rotatable about the guide axis with respect to the lens moving body, and movable in the optical axis direction integrally with the lens moving body;
An urging unit disposed between the auxiliary moving body and the lens moving body, and urging the lens moving body in a predetermined direction around the guide axis with respect to the auxiliary moving body;
A camera module comprising:

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