JP4951871B2 - Zoom lens device and portable electronic device - Google Patents

Description

  The present invention relates to a zoom lens apparatus that includes a plurality of lens groups and is mounted on a camera or the like, and particularly relates to a zoom lens apparatus that includes a zoom mechanism that changes the position of the lens group in a stepped manner.

  A so-called step zoom mechanism in which a plurality of lens groups are mounted on a camera in which a plurality of lens groups are moved between a short focal length position (wide position) and a long focal length position (tele position). A multifocal magnification switching lens barrel including the above is disclosed in Patent Document 1. In this multifocal magnification switching lens barrel, a fixed cylinder is inserted into a rotating cylinder, and a first moving cylinder holding a front group lens and a second moving cylinder holding a rear group lens are inserted into the fixed cylinder. Has been.

  The rotary cylinder is provided with a zoom lens cam groove for the front lens group and a zoom cam groove for the rear lens group for guiding the first and second movable cylinders, respectively. The fixed cylinder is formed with a focus adjustment cam groove having an inflection portion and a guide groove for guiding the first moving cylinder. A cam pin that engages with the magnification change cam groove and the guide groove for the front group lens is formed in the first moving cylinder, and the magnification change cam groove and the focus adjustment cam groove for the rear group lens are formed. An engaging cam pin is formed on the second movable cylinder.

  Further, a gear portion is provided on the outer peripheral surface of the rear end portion of the rotary cylinder, and the rotary cylinder rotates about the optical axis as a rotation axis by driving of a motor. By rotating the rotating cylinder, zooming and focus adjustment are performed simultaneously.

  That is, when the rotating cylinder is slightly rotated to the feeding side, the first moving cylinder moves linearly along the guide groove of the fixed cylinder, but the second moving cylinder is at the inflection portion of the focus adjustment cam groove. It bends and the amount of movement in the optical axis direction is smaller than that of the first moving cylinder. During this time, there is no change in the magnification of the lens system, and focus adjustment is performed from an infinite distance to a close distance in a wide state. By providing a plurality of such inflection portions in the focus adjustment cam groove, the focus adjustment can be performed at each magnification in each inflection portion.

  Using the concept of step zoom in the above-described multifocal magnification switching lens barrel, a zoom lens device having the following cam can be considered.

  As shown in FIG. 8, the zoom lens device includes a motor 61 as a driving source, a cam 63 formed by a spiral rib projecting from a cylindrical rotating shaft 62, and light on the image sensor 64. A lens system H arranged on the axis O is provided.

  Gears (hereinafter referred to as “first gear” and “third gear”) 65 and 66 are attached to the rotation shaft of the motor 61 and the rotation shaft of the cam 63. The first and third gears 65 and 66 mesh with an intermediate gear (hereinafter referred to as “second gear”) 67 to transmit the rotational force.

  A surface on the outer side (left side in the drawing) of the cam 63 is a zoom cam surface 68 and a surface on the back side (right side in the drawing) is a focusing cam surface 69. A plurality of (here, five) flat portions and inclined portions are alternately formed on the zoom cam surface 68. The focusing cam surface 69 is formed only with an inclined portion.

  In the lens system H, the first lens group 71, the second lens group 72, and the third lens group 73 are arranged from the outer side to the rear side on the optical axis O, and the third lens group 73 and the imaging element 64 face each other. ing. The role of the second lens group 72 is mainly to change the focal length of the lens system H (zoom operation), and the role of the third lens group 73 is to mainly adjust the imaging position of the lens system H, that is, the image sensor 64. Focusing (focusing operation).

  The first lens group 71 is held by a holding frame (not shown) that does not move. The second lens group 72 and the third lens group 73 are each a holding frame (hereinafter referred to as a “second holding frame” or a “third holding frame”) 74 that individually moves in the same direction as the optical axis O. 75.

  A pair of guide shafts 76 and 76 pass through the second holding frame 74 and the third holding frame 75, and the both holding frames 74 and 75 are guided by the guide shafts 76 and 76 and moved. The zoom follower portion 77 provided on the second holding frame 74 is joined to the zoom cam surface 68 by a spring or the like (not shown), and the focus follower provided on the third holding frame 75. The portion 79 is joined to the focusing cam surface 69 by a spring or the like (not shown).

  The zoom lens apparatus is configured as described above, and the operation will be described with reference to FIG. When the motor 61 rotates, this driving force is transmitted to the rotating shaft 62 of the cam 63 by the first, second, and third gears 65, 67, 66, and the cam 63 rotates. Then, the joint portion between the zoom follower portion 77 and the zoom cam surface 68 and the joint portion between the focus follower portion 79 and the focus cam surface 69 move outward or in the back direction along the same direction as the optical axis O. To do.

  However, since the zoom cam surface 68 has alternately flat portions and inclined portions, the zoom follower portion 77 is moved while moving on the flat portion as shown by the solid line in FIG. It does not move in the outward direction but moves in the outward direction only while moving on the inclined part. Accordingly, the zoom follower 77 and the second lens group 72 move in a step shape, and a zoom operation is performed.

On the other hand, since the focusing cam surface 69 is formed only of the inclined portion, the focusing follower portion 79 continuously moves outward as indicated by a broken line in FIG. Therefore, even if the motor 61 continues to rotate and the cam 63 continues to rotate, the zoom follower 77 is joined to the flat portion of the zoom cam surface 68 and the second lens group 72 is stopped. A focusing operation is performed by moving the third lens group 73. Thus, according to this zoom lens device, both the zoom and focus operations are performed by the single motor 61.
JP-A-9-329733

  The above conventional example is based on the premise that a zoom lens system based on an optical design in which the movement of the focus mechanism substantially follows the movement of the zoom mechanism is used. In addition, the movement trajectory of the lens that performs the zoom movement is partially devoted to the focus movement.

  However, in the case of a zoom optical system based on an optical design that has a characteristic that the trajectory of the focus motion deviates greatly from the trajectory following the zoom motion, in other words, the trajectory of the focus motion and the trajectory of the zoom motion are highly independent. It is difficult to realize a step zoom operation suitable for practical use by applying the configuration of the example.

  For example, in a zoom optical system that performs a focus movement by moving a lens group close to the imaging plane side, the lens movement locus for the focus movement often follows that of the zoom movement. On the other hand, in a zoom optical system in which the focus movement is performed by moving the lens group close to the subject side, the lens movement locus for the focus movement often deviates greatly from that of the zoom movement. Therefore, it becomes difficult to construct a step zoom lens apparatus using the configuration of the conventional example in the latter zoom optical system.

  By the way, the latter zoom optical system often has a larger amount of movement of the focus movement than the former, and has the design advantage that the focus accuracy is easy to maintain without satisfying the high design accuracy as the former. ing. Nevertheless, due to the above-described problems, it has been difficult to provide a high-quality zoom lens apparatus using such a zoom optical system.

  Therefore, the present invention is effective in improving the quality as in a zoom optical system in which the focus movement is performed by moving the lens group close to the subject side, for example, but the lens movement locus for the focus movement greatly deviates from that of the zoom movement. It is an object of the present invention to provide a zoom lens device that can use an optical system having the above characteristics.

  The zoom lens device of the present invention includes a lens system in which a plurality of lens groups are arranged on the optical axis, and a focal length of the lens system is changed by moving one or more lens groups in the same direction as the optical axis, and One or more zoom mechanisms for stopping movement of the one or more lens groups for a predetermined period at a predetermined focal length; and one or more zoom mechanisms by moving one or more of the zoom mechanisms in the same direction as the optical axis. A focus mechanism that moves the lens group in the same direction as the optical axis to adjust the imaging position of the lens system, and a driving force transmission means that transmits a driving force from one driving source to the focus mechanism and the zoom mechanism. The focus mechanism moves one or more of the zoom mechanisms in the same direction as the optical axis during a period in which the zoom mechanism is in a state of stopping the one or more lens groups. There.

  According to this configuration, the zoom mechanism realizes a so-called step zoom operation by moving in the same direction as the optical axis in a step-like manner so that one or more lens groups are stopped and moved. At the same time, in each zoom step (stopped state) in the step zoom, the focus mechanism performs focus adjustment by moving one or more of the zoom mechanisms in the same direction as the optical axis. That is, the focus movement can be made to correspond to a movement that is highly independent of the zoom movement, as compared to the case where the movement locus of the lens that performs the zoom movement is partially used for the focus movement as in the conventional example. Therefore, according to this zoom lens device, for example, even when an optical system in which the movement locus of the lens for the focus movement deviates greatly from that of the zoom movement can be used, it is possible to cope with the focus adjustment in each zoom step. It becomes possible to provide a step zoom device corresponding to the lens design. In particular, when a zoom optical system that performs focus movement by moving a lens group close to the subject side is used, the focus movement amount is generally large, so that the accuracy is easily maintained, which is effective in improving the quality of the zoom lens apparatus. In addition, since both the zoom mechanism and the focus mechanism can be driven by one drive source, it is advantageous for downsizing of the apparatus.

  Further, the zoom mechanism may intermittently transmit the driving force from the driving source via an intermittent transmission mechanism. According to this configuration, in addition to the above actions and effects, the operation of the zoom mechanism can be intermittently stopped by the intermittent transmission mechanism, so that the zoom motion can be stopped intermittently. Similar actions and effects can be achieved. Further, by using the intermittent transmission mechanism, for example, when the zoom mechanism traces the cam, it is not necessary to provide a flat portion on the cam as in the conventional example, and the size can be reduced.

  In the zoom lens device, it is preferable that the intermittent transmission mechanism is a Geneva mechanism.

  The Geneva mechanism is a combination of a prime mover and a follower, and the prime mover has an arc-shaped convex portion and is provided with one pin outside the arc-shaped convex portion. The driven wheel is formed with an arcuate concave surface that engages with the arcuate convex surface and a plurality of radial grooves into which the pins are engaged. When the driving force of one drive source is transmitted to the prime mover and the pin of the rotating prime mover is engaged in the radial groove of the follower, the follower rotates and the pin comes off the radial groove. The follower stops.

  Therefore, according to this zoom lens device, in addition to the above-described operation and effect, the intermittent transmission mechanism is configured by a Geneva mechanism, so that it is possible to cope with a large number of steps while having a simple configuration. This is advantageous for downsizing without sacrificing usability.

  In the zoom lens device, the intermittent transmission mechanism may be a parallel index cam mechanism.

  The parallel index cam is a combination of a prime mover and a follower, and the prime mover is a plate cam formed with a bulge, and the follower is concentrically shaped with a plurality of pins joined to the plate cam. Projected to The driving force of one drive source is transmitted to the prime mover, and the driven vehicle rotates only while the bulge of the prime mover applies a rotational force to the pin of the follower, and is driven when the bulge is removed from the pin. The car stops.

  Therefore, according to the zoom lens device, in addition to the above-described operation and effect, the intermittent transmission mechanism is configured by the parallel index cam mechanism, so that the play of the cam mechanism can be reduced while the configuration is simple, and the higher This is advantageous in performing a precise zoom operation.

  As described above, according to the zoom lens device of the present invention, the zoom mechanism is moved stepwise in the same direction as the optical axis so as to repeat the stopped state and the moved state of one or more lens units. In addition to realizing so-called step zoom operation, the focus mechanism adjusts the focus by moving one or more of the zoom mechanisms in the same direction as the optical axis in each zoom step (stopped state) in such step zoom. Like to do. That is, it is possible to make the movement of the focus movement highly independent of the zoom movement, compared to the case where the movement locus of the lens that performs the zoom movement is partially used for the focus movement as in the conventional example. Therefore, according to this zoom lens device, for example, even when using an optical system in which the movement locus of the lens for the focus movement deviates greatly from that of the zoom movement, the focus adjustment can be performed at each zoom step, and any lens can be used. It becomes possible to provide a step zoom device corresponding to the design. In particular, when a zoom optical system that performs focus movement by moving a lens group close to the subject side is used, the focus movement amount is generally large, so that the accuracy is easily maintained, which is effective in improving the quality of the zoom lens apparatus.

(Embodiment 1)
Embodiment 1 of the present invention will be described with reference to FIG.

  This zoom lens apparatus includes a lens system A, a driving force transmission means B, an intermittent transmission mechanism C, a zoom mechanism D, and a focus mechanism E.

  The lens system A includes a first lens group 11, a second lens group 12, and a third lens group 13 arranged on the optical axis Z from the subject side (left side in FIG. 1) to the imaging surface side (right side in FIG. 1). The third lens group 13 faces the image sensor 20 and is held by a holding frame (not shown) that does not move. The first lens group 11 and the second lens group 12 are held by a first holding frame 14 and a second holding frame 15 that move individually. A pair of guide shafts 16, 16 pass through the first and second holding frames 14, 15, and the first lens group 11 and the second lens group 12 are restricted by the guide shaft 16 and are on the optical axis Z. To move to.

  As the first lens group 11 and the second lens group 12 move, the lens system A changes the focal length (zoom operation) and adjusts the image formation position of the lens system A, that is, applies to the image sensor 20. Focusing is performed. Each lens group is optically designed so that the second lens group 12 mainly plays a role of a zoom operation, and the first lens group 11 mainly plays a role of a focus operation. At this time, when the first lens group 11 and the second lens group 12 are zoomed, that is, when the focal length is changed, an example of the locus of each optical axis direction position is as shown in FIG.

  In the figure, the broken line indicates the position of the first lens group 11 that forms an image with respect to the nearest point, the alternate long and short dash line indicates the position of the first lens group 11 that forms an image with respect to infinity, and the solid line indicates the position of the second lens group 12. It is a movement trajectory. That is, in the case of the design of the lens system A as described above, the focus movement is performed by the movement of the first lens group 11 close to the subject side, and the movement locus of the lens for the focus movement is significantly different from that of the zoom movement. ing.

  As shown in FIG. 1, the driving force transmission means B includes a gear train 3, a final gear 31, and the like, and transmits the driving force from the motor 2, which is one drive source, via the gear train 3. It transmits to the gear 31. The final stage gear 31 is rotatable integrally with the prime mover 4, and the driving force from the motor 2 is transmitted to the intermittent transmission mechanism C via the prime mover 4.

  The intermittent transmission mechanism C includes a Geneva mechanism F. The Geneva mechanism F is configured by combining the driving vehicle 4 attached to the driving shaft 41 and the driven vehicle 5 attached to the driven shaft 51.

  As shown in FIG. 4, the prime mover 4 is formed with a projecting portion 44 including an arc-shaped convex portion 42 and an arc-shaped concave portion 43, and a pin 7 is provided outside the arc-shaped concave portion 43. . On the other hand, the driven vehicle 5 has a plurality of (five in the drawing) in which the circular arc-shaped concave surface 53 engaged with the circular arc-shaped convex portion 42 and the pin 7 are engaged with a disk 52 fixed to the driven shaft 51. However, the radial grooves 54, 54... Are formed at a constant angle θ.

  As shown in FIG. 1, when the final stage gear 31 rotates, the driving shaft 41 rotates. Then, the pin 7 of the prime mover 4 rotates continuously. However, the driven vehicle 5 rotates only while the pin 7 is engaged in the radial groove 54. That is, the driven vehicle 5 rotates intermittently. The driving force from the intermittent transmission mechanism C is transmitted to the zoom mechanism D.

  The zoom mechanism D includes a first cam 9, a second cam 23, a cam follower 17 provided on the first holding frame 14 of the first lens group 11, and a second holding frame of the second lens group 12. 15 and a cam follower 18 provided in the vehicle.

  A cam surface 21 is formed on the first cam 9, and the cam follower 17 of the first lens group 11 of the lens system is in contact with the cam surface 21. The contact is maintained with an appropriate pressing force by a spring (not shown).

  A second cam 23 is arranged with the same axis as the first cam 9. The second cam 23 is configured to be rotatable around the driven shaft 51, but not movable in the axial direction. The first cam 9 and the second cam 23 are fitted by a key 24 and a key groove 25, and the rotational torque of the first cam 9 is transmitted to the second cam 23. Yes. The fitting between the key 24 and the key groove 25 does not come off even if the first cam 9 moves in the axial direction.

  A cam surface 26 is formed on the second cam 23. The cam follower 18 of the second lens group 12 of the lens system is in contact with the cam surface 26. The contact is maintained with an appropriate pressing force by a spring (not shown).

  The driving force from the motor 2 is also transmitted to the focus mechanism E via the prime mover 4.

  The focus mechanism E includes a prime mover 4 having a cam surface 8 formed on the right side in the drawing, a cam follower 17 of the first lens group 11, and a first cam 9.

  As shown in FIG. 3, the cam surface 8 is formed in a shape that draws a V shape or a U shape in the circumferential direction and returns to the initial position. A perspective view of the prime mover 4 provided with such a cam surface 8 is shown in FIG.

  The first cam 9 is configured to rotate and move integrally with the driven vehicle 5. Typically, the first cam 9 forms a part of the driven vehicle 5. The first cam 9 is arranged to contact the cam surface 8 of the prime mover 4 at a contact point P at the left end thereof. The contact is maintained with an appropriate pressing force by a spring (not shown). The first cam 9 and the driven vehicle 5 that is integral with or part of the first cam 9 are configured to be rotatable around the driven shaft 51 and to be parallel to the driven shaft 51 in the axial direction.

  The operation of this embodiment will be described below.

  It is assumed that the motor 2 rotates counterclockwise (CCW) with a line of sight in the X direction in the figure. The rotation is transmitted to the gear train 3, and the final stage gear 31 and the prime mover 4 are rotated in CCW. At this time, the rotation operation of the prime mover 4 is intermittently transmitted to the driven vehicle 5 by the intermittent transmission mechanism C described above. Here, the rotational relationship between the driving vehicle 4 and the driven vehicle 5 will be described with reference to FIGS.

  That is, as shown in FIG. 4A, the driven vehicle 5 is rotated until the driving wheel 4 rotates counterclockwise CCW and the pin 7 is engaged with the adjacent radial groove 54 from the radial groove 54 with the pin 7. It has stopped. Accordingly, the first cam 9 and the second cam 23 do not rotate, and the first lens group 11 and the second lens group 12 of the lens system contacting the respective cams are in a state where the zoom operation is stopped.

  Subsequently, as shown in FIG. 4 (b), the pins 7 provided on the rotating motor vehicle 4 are engaged in the radial grooves 54, and as shown in FIG. 4 (c), the pins 7 are radial. The driven vehicle 5 rotates in the clockwise direction CW by an angle θ until it exits from the groove 54. During this time, the driven shaft 51 is also rotated by the angle θ, and the first cam 9 and the second cam 23 are also rotated by the angle θ by this rotation, and the first lens group 11 and the first lens group 11 of the lens system contacting the respective cams. The two lens group 12 moves in the optical axis direction by a predetermined amount defined by the curve of the cam surface. That is, the zoom operation proceeds by one step.

  Subsequently, as shown in FIG. 4C, until the pin 7 comes off the radial groove 54 and engages with the adjacent radial groove 54, only the driving vehicle 4 rotates and the driven vehicle 5 continues to rotate. Does not rotate. Accordingly, even during this time, neither the first cam 9 nor the second cam 23 rotates, and the zoom operation is stopped.

  As described above, the continuous rotational motion supplied from the motor 2 is converted into an intermittent motion that repeats the rotational motion period and the rotation stop period, and is transmitted to the first cam 9 and the second cam 23.

  On the other hand, as shown in FIG. 1, since the illustrated left end of the first cam 9 is disposed so as to contact the cam surface 8 of the prime mover 4, the contact point position P between the two is changed as the prime mover 4 rotates. Displacement along the cam surface 8 causes the first cam 9 to move in the axial direction.

  As described above, since the cam surface 8 has a V-shaped or U-shaped shape in the circumferential direction and returns to the initial position, the first cam 9 moves in the axial direction as the prime mover 4 rotates. One reciprocal translation is required. Then, the formation angle around the axis of the cam surface 8 is appropriately designed with the position of the pin 7 as a reference, and the first cam 9 is in a period in which the pin 7 is engaged with one of the five radial grooves 54 of the driven vehicle 5. Is configured not to move in the axial direction, but to move back and forth in the axial direction only during a period when it does not mesh with any of the five radial grooves 54. Hereinafter, such an axial movement of the first cam 9 is schematically shown in FIGS.

  That is, as shown in FIG. 5A, when the pin 7 of the prime mover 4 is engaged with the follower vehicle 5 and transmits the driving force, the prime mover 4 has the V-shape or The parts other than the U-shaped part are in contact with each other so that the driven vehicle 5 and the first cam 9 do not move in the axial direction. At this time, the first lens group 11 does not move independently and the focusing operation is not performed. However, since the driving force is transmitted to the driven vehicle 5, the first cam 9 and the second cam 23 have a rotational driving force. The zoom operation is performed.

  Subsequently, as shown in FIG. 5 (b), when the pin 7 of the prime mover 4 is disengaged from the follower vehicle 5 and the rotational drive force is not transmitted to the follower vehicle 5, the first cam 9 is attached to the prime mover 4. The movement starts in the left direction in the figure along the V-shaped or U-shaped portion of the cam surface 8. At this time, the first lens group 11 starts to move in the left direction in the figure and starts a focusing operation. On the other hand, since the rotational driving force is not transmitted to the driven vehicle 5, the zoom operation is stopped.

Subsequently, as shown in FIG. 5 (c), the pin 7 of the prime mover 4 is continuously detached from the follower 5, and the first cam 9 is V-shaped or U-shaped on the cam surface 8 of the prime mover 4. It reaches the valley of the mold part and reaches the left end in the figure. At this time, the first lens group 11 moves to the leftmost end in the focusing operation. On the other hand, since the rotational driving force is not transmitted to the driven vehicle 5, the zoom operation is stopped.

  Subsequently, as shown in FIG. 5 (d), the pin 7 of the prime mover 4 is continuously detached from the follower 5, and the first cam 9 is the V-shaped or U shape of the cam surface 8 of the prime mover 4. Return to the initial position beyond the character-shaped part and return to the right end in the figure. At this time, the first lens group 11 returns to the rightmost end in the focusing operation. On the other hand, since the rotational driving force is not transmitted to the driven vehicle 5, the zoom operation is stopped.

  Subsequently, as shown in FIG. 5 (e), the pin 7 of the driving vehicle 4 is reengaged with the driven vehicle 5 to transmit the driving force to the driven vehicle 5, and the first cam 9 is The cam surface 8 of the moving vehicle 4 abuts at a portion other than the V-shaped or U-shaped portion, and the driven vehicle 5 and the first cam 9 do not move in the axial direction. At this time, the first lens group 11 does not move independently and the focusing operation is not performed. On the other hand, since the driving force is transmitted to the driven vehicle 5, the rotational driving force is applied to the first cam 9 and the second cam 23. Is transmitted and the zoom operation is started.

  FIG. 6 shows the movement locus of the first lens group 11 and the second lens group 12 based on the above operation. In this figure, the total rotation angle of the motor 2 is drawn on the horizontal axis, and q1, q3, q5 and q9 on the horizontal axis represent the positions indicated by the solid line of the pin 7 in FIG. , Q4, q6, and q8 represent positions indicated by broken lines of the pin 7 in FIG. In the figure, the broken line indicates the position of the first lens group 11 that forms an image with respect to the nearest point, the alternate long and short dash line indicates the position of the first lens group 11 that forms an image with respect to infinity, and the solid line indicates the first lens group 11. The two-dot chain line indicates the movement locus of the second lens group 12.

  The sections F1 to F5 are sections in which the first cam 9 and the second cam 23 do not rotate and only the first cam 9 reciprocates in parallel, while the sections Z1 to Z4 are the first cam 9 and the second cam respectively. This is a section in which the cam 23 rotates. That is, the sections F1 to F5 correspond to each zoom step, and the sections Z1 to Z4 correspond to transition periods between adjacent steps.

  When the second lens group 12 is moved stepwise as indicated by a two-dot chain line in the figure by the intermittent transmission mechanism C, the theoretical position of the first lens group 11 that forms an image with respect to each of the nearest and infinity is as follows. They are as shown by the broken line and the alternate long and short dash line in the figure.

  Here, if the shape of the cam surface 8 on the prime mover 4 is appropriately formed as described above, the locus of the first lens group 11 goes to infinity in each of the sections F1 to F5 as indicated by the solid line in the figure. From the position Pf [i] · Pf [i] ′ (1 ≦ i ≦ 5) corresponding to the imaging of the first position, the position Pn [i] · Pn [i] ′ (1 ≦ i) corresponding to the imaging to the nearest point It can be configured to include a range up to ≦ 5). Therefore, according to the configuration, in each zoom step, only the first lens group 11 can be moved to realize the focusing operation.

  The focus operation in each zoom step may use a range of Pn [i] to Pf [i] (1 ≦ i ≦ 5), or Pn [i] ′ to Pf [i] ′ (1 ≦ The range of i ≦ 5) may be used, or both may be used.

  The control of this embodiment will be described. A sensor 34 is installed in the vicinity of the second lens group 12 of the lens system, and the amount of movement of the second lens group 12 is detected by the sensor 34 and sent to the controller 32. The controller 32 monitors the detected movement amount, and drives and controls the motor 2 using the power supplied from the power source 33. The installation location of the sensor 34 is not necessarily limited to this. For example, the same effect can be obtained by installing the sensor 34 at a position where the rotation angle of the first cam 9 or the second cam 23 is detected.

  In the above description, the rotation of the motor is the CCW direction, but of course, the operation is the same in the reverse rotation of the CW direction.

  According to the zoom lens device described above, the zoom mechanism D is moved stepwise in the same direction as the optical axis so as to repeat the stopped state and the moved state of the first lens group 11 and the second lens group 12. Thus, a so-called step zoom operation is realized, and in each zoom step in the step zoom, the focus mechanism E performs focus adjustment by moving the first cam 9 in the same direction as the optical axis. Yes. That is, the focus movement can be made to correspond to a movement that is highly independent of the zoom movement, as compared to the case where the movement locus of the lens that performs the zoom movement is partially used for the focus movement as in the conventional example. Therefore, according to this zoom lens device, for example, even when an optical system in which the movement locus of each lens group for the focus movement deviates greatly from that of the zoom movement is used, focus adjustment can be performed at each zoom step. It becomes possible to provide a step zoom device corresponding to any lens design. In particular, the focus movement is performed by moving the first lens group 11 close to the subject side, and since the focus movement amount is generally large, the accuracy is easily maintained, which is effective in improving the quality of the zoom lens apparatus.

(Embodiment 2)
Next, a zoom lens apparatus according to a second embodiment of the present invention will be described with reference to FIG. The second embodiment is characterized in that the intermittent transmission mechanism C is a parallel index cam mechanism G as shown in FIG. Other configurations are the same as those of the zoom lens apparatus according to the first embodiment.

  The parallel index cam mechanism G is a combination of a driving vehicle 40 and a driven vehicle 50, and the driving vehicle 40 is formed by forming a bulging portion 47 on a plate cam 46. The driven vehicle 50 is joined to the plate cam 46. .. Are formed concentrically on a disk 49, and the bulging portion 47 has a rotational force on the pin 48. The follower vehicle 50 is rotated by giving the above. The driving vehicle 40 is fixed to the driving shaft 41, and the driven vehicle 50 is fixed to the driven shaft 51.

  Since the other configuration is the same as that of the first embodiment, the operation will be described next. When the motor 2 rotates, the driving force is transmitted to the final stage gear 31 via the gear train 3, and the driving shaft 41 rotates, so that the driving vehicle 40 rotates continuously.

  The driven vehicle 50 rotates only while the bulging portion 47 of the prime mover 40 applies a rotational force to the pin 48 of the driven vehicle 50, and the driven vehicle 50 stops when the bulging portion 47 comes off the pin 48. . When the driven vehicle 50 is rotating, the zoom mechanism D is operated, and the zoom operation is performed by moving the first lens group 11 and the second lens group 12.

  When the driven vehicle 50 is stopped, the zoom mechanism D is also stopped, and the first lens group 11 and the second lens group 12 are also stopped. Thus, the first lens group 11 and the second lens group 12 are moved stepwise by the parallel index cam mechanism G. On the other hand, the focus mechanism E operates the first cam 9 in the axial direction and moves the first lens group 11 during this period, thereby performing the focus operation.

  As described above, in this zoom lens device, the intermittent transmission mechanism C is constituted by the parallel index cam mechanism G, so that the same operations and effects as those of the first embodiment can be achieved, and the intermittent transmission mechanism C can be reduced in size. Therefore, the zoom lens apparatus can be miniaturized.

  Of course, the present invention is not limited to the above-described embodiment, and can be applied to all other uses. For example, the intermittent transmission mechanism C is not limited to the Geneva mechanism F or the parallel index cam mechanism G. For example, a combination of a rotating claw and a claw wheel or a combination of a pin wheel and a gear is adopted. You can also

  The present invention is suitable for a zoom lens apparatus having a so-called step zoom mechanism in which a plurality of focal lengths are selected, and in particular, an optical system in which the lens movement locus for the focus movement deviates greatly from that of the zoom movement. It is suitable for the zoom lens device used.

1 is a schematic front view of a zoom lens apparatus according to Embodiment 1 of the present invention. The figure which shows the movement locus | trajectory of a lens group with respect to the focal distance change in the zoom lens apparatus which concerns on Embodiment 1 of this invention. 1 is a perspective view of a prime mover in a zoom lens device according to Embodiment 1 of the present invention. FIG. 2 is a YY cross-sectional view showing an intermittent transmission mechanism in the zoom lens apparatus according to Embodiment 1 of the present invention, where (a) is a cross-sectional view showing the beginning of the operation, and (b) is a cross-sectional view showing the middle of the operation. (C) is sectional drawing which shows the final state of operation | movement. The figure which shows the change of the axial direction position of the 1st cam accompanying rotation of the motor vehicle of FIG. The figure which shows the movement locus | trajectory of each lens group with respect to the total rotation angle of the motor in the zoom lens apparatus which concerns on Embodiment 1 of this invention. Schematic front view of a zoom lens apparatus according to Embodiment 2 of the present invention. Schematic front view of a conventional zoom lens device The figure which shows the movement locus | trajectory of the lens group in the conventional zoom lens apparatus.

Explanation of symbols

2 Motor 4 Driving car 5 Driven car 9 First cam 11 First lens group 12 Second lens group 13 Third lens group 14 First holding frame 15 Second holding frame 16 Guide shaft 17 Cam follower 18 Cam follower 23 Second Cam

Claims (2)

A lens system in which a plurality of lens groups on which one or more lenses operate integrally is arranged on the optical axis, and one or more lens groups among the plurality of lens groups of the lens system are moved in the optical axis direction. A zoom mechanism that performs a zoom operation that changes the focal length of the lens system, and a focus lens group that is at least one lens group of the lens system is moved in the optical axis direction independently of the zoom operation. In the zoom lens apparatus, comprising: a focus mechanism that performs a focusing operation for adjusting an image forming position of the zoom lens; and a driving force transmission unit that transmits a driving force from one driving source to the zoom mechanism and the focus mechanism. means the lens system in the zoom operation in each state forming a plurality of predetermined focal length, is moved by the zoom mechanism Serial movement of other lens group except for the focusing lens group of one or more lens groups so that a predetermined period stops, driving the zoom mechanism with the intermittent transmission mechanism consisting of the Geneva mechanism or parallel indexing cam mechanism In addition, the zoom lens apparatus is configured such that the focus mechanism moves only the focus lens group in the optical axis direction during the stop period. A portable electronic device on which the zoom lens device according to claim 1 is mounted.

Images