JP2005227444A - Optical device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an optical device using an electrostatic actuator, whose entire length is shortened when it is not used for photography, which is miniaturized and thinned in an optical axis direction, and also which realizes smooth zooming without focus moving by easy control. <P>SOLUTION: The optical device has an optical system having at least two moving lens groups moving independently in the optical axis direction, and the electrostatic actuator moving the moving lens group in the optical axis direction. The electrostatic actuator has a 1st pair of stators and a 2nd pair of stators obtained by pairing two stators arranged to be opposed while putting the optical axis of the optical system in between and having electrodes, and the 1st and the 2nd pairs of stators are arranged to surround the optical axis of the optical system, and the 1st pair of stators moves either moving lens group of the optical system and the 2nd pair of stators moves the other. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optical device, and more particularly to an optical device using an electrostatic actuator using electrostatic force so that a plurality of lens groups can be moved independently of each other.

  In recent years, an imaging device that captures a subject image with a solid-state imaging device has been mounted on a small and thin portable terminal such as a mobile phone or a PDA (Personal Digital Assistant), thereby not only providing audio information to a remote place. Image information can also be transmitted to each other. These imaging devices are desired to be extremely small and thin so that they can be built in a portable terminal.

  On the other hand, these imaging devices are aiming for higher functionality as the penetration rate improves, and not only pan-focus shooting using a deep depth of field by fixing the imaging optical system but also moving the imaging optical system. There is a demand for mounting close-up photography (macro photography) and variable focal length optical system (zoom optical system).

  In response to these demands for miniaturization and higher functionality, various optical devices using electrostatic actuators have been proposed as actuators capable of directly moving optical systems individually.

For example, in an optical device using an electrostatic actuator, a pair of stators having electrode portions and a plurality of movers arranged between the stators and attached with optical elements are independently moved in the optical axis direction. What has been made possible is disclosed (for example, see Patent Document 1 and Patent Document 2).
Japanese Patent Laid-Open No. 10-239578 JP 2002-199747 A

  The optical devices described in Patent Documents 1 and 2 described above have an advantage that they can be formed on the outer shape including the zoom optical system without requiring a protrusion or the like, and can be configured to be thin in the optical axis direction. However, the length in the optical axis direction and drive control have the following problems.

  The optical devices described in Patent Documents 1 and 2 require a stator having an electrode portion over a movable range on the optical axis of a plurality of movers to which optical elements are attached. For this reason, in the case of a zoom optical system, a stator having an electrode portion must be disposed near the position where a lens group disposed on the object side is extended during photographing. For example, when a general camera is not used for photographing, Thus, even if the mover including the front group is moved to the image sensor side, the stator remains as it is, and the total length of the optical device (the length from the image plane to the forefront of the optical device) is shortened. There is a problem that you can not.

  In addition, when the movement control of the lens position as described in Patent Document 2 is performed, the lens group disposed on the object side (hereinafter referred to as the front group) moves backward during zooming from the wide end to the intermediate angle of view. Therefore, the lens group arranged on the image plane side (hereinafter referred to as the rear group) needs to be moved forward. Conversely, when zooming from the intermediate angle of view to the wide direction, the front group is moved forward and the rear group is moved backward. There is a problem that it is necessary to move the other in a state where one is stopped, and in addition to complicated control, there is a problem that a smooth zooming operation cannot be performed. In addition, a focus shift occurs when only one lens group is moved, and a preview when a display device such as an LCD commonly used in an imaging device built in a portable terminal is used as a viewfinder The image also has a drawback that it does not become a smooth zoomed image by zooming while repeating a blurred image and a focused image during zooming.

  In view of the above problems, the present invention can shorten the overall length of the optical device when not used for photographing, enable miniaturization and thinning in the optical axis direction, and can perform smooth zooming without a focus shift by simple control. An object of the present invention is to obtain an optical device using an electrostatic actuator.

  The above object can be solved as follows.

  1) An optical apparatus comprising: an optical system having at least two moving lens groups that move independently in the optical axis direction; and an electrostatic actuator that moves the moving lens groups in the optical axis direction. Comprises a pair of two stators having electrodes, which are arranged opposite to each other across the optical axis of the optical system, and has a first stator pair and a second stator pair. And the second stator pair are arranged so as to surround the optical axis of the optical system, and the first stator pair moves one moving lens group of the optical system, and the second fixed An optical device characterized in that the child pair is configured to move the other moving lens group of the optical system.

  2) The optical device according to 1), wherein an arrangement pitch of electrodes formed on at least one of the pair of stators is different between the pair of first and second stators.

  3) Of the first stator pair and the second stator pair, the arrangement pitch of the stator electrodes for moving the moving lens group arranged on the object side is smaller than the other arrangement pitch 1) Or the optical device of 2).

  4) The optical device according to any one of 1) to 3), wherein focusing is performed by moving a moving lens group disposed on the object side.

  According to the present invention, when not used for photographing, an electrostatic actuator that can retract the lens group to shorten the total length in the optical axis direction and can be thinned in the optical axis direction even with a zoom optical system is used. Can be obtained. In addition, even if the moving directions of the lens groups are contradictory, the lens group can be moved smoothly with simple control, and smooth zooming operation and focus movement during zooming can be suppressed.

  In the optical device of the present invention, it is preferable that the arrangement pitch of the electrodes formed on at least one of the pair of stators is different between the pair of the first and second stators. Corresponding to each moving specification, the moving step amount can be made different, and the stop position accuracy at the time of zooming can be optimized.

  Further, in the optical device of the present invention, the arrangement pitch of the electrodes of the stator that moves the lens group arranged on the object side out of the pair of the first stator and the second stator is smaller than the other. It is preferable to perform focusing by moving the lens group arranged on the object side, and it becomes possible to perform more accurate focusing with fine steps with a smaller arrangement pitch.

  Hereinafter, the present invention will be described in detail with reference to embodiments, but the present invention is not limited thereto.

  FIG. 1 is an exploded perspective view showing a schematic configuration of an optical device according to an embodiment of the present invention.

  In the figure, 1 is an optical axis of the optical device, and 2 is an image sensor. The imaging device 2 is a solid-state imaging device such as a CCD (Charge Coupled Device) type image sensor or a CMOS (Complementary Metal-Oxide Semiconductor) type image sensor. The image sensor 2 is mounted on the mounting substrate 7.

  As shown in the figure, the stators 3a and 3b having electrodes with the optical axis 1 interposed therebetween are arranged facing the X direction (horizontal direction) in the figure. Further, a stator 4a, 4b having electrodes sandwiching the optical axis 1 is opposed in the Y direction (vertical direction) in the figure, and a square is formed so as to surround the optical axis 1 by the stators 3a, 3b and 4a, 4b. It is arranged in a cylindrical shape. Further, the movable element 5 and the movable element 6 are arranged inside a rectangular tube formed by the stators 3a, 3b and 4a, 4b.

  The movers 5 and 6 are formed of a conductive material, for example, melt-kneaded with a thermoplastic resin such as vapor-grown carbon fiber (VGCS) and PPS (polyphenylene sulfide) described in JP-A-2003-284359. It is formed with the conductive resin etc. which were shape | molded with the resin composition formed.

  The mover 5 is formed in a U-shape, and the U-shaped portion has a mover electrode portion 5a facing the stator 3a and a mover electrode (not shown) facing the stator 3b. A portion 5b is formed and is configured to be driven in a direction parallel to the optical axis 1 by a pair of stators 3a and 3b. A lens group 5c is assembled at the center.

  The mover 6 is formed in a shape that can enter the U-shaped part of the mover 5. The mover 6 faces the stator 4 a and faces the mover electrode part 6 a and the stator 4 b (not shown). A mover electrode portion 6b is formed and is configured to be driven in a direction parallel to the optical axis 1 by a pair of stators 4a and 4b. A lens group 6c is assembled at the center.

  In the figure, the housing for holding the mounting boards 7 on which the stators 3a, 3b and 4a, 4b and the image sensor 2 are mounted is omitted.

  FIG. 2 is a perspective view of the mover 5. This figure is a perspective view of the mover 5 from a direction different from that in FIG. In the following drawings, the same symbols are assigned to the same elements as those described above in order to avoid duplication of explanation.

  As shown in FIG. 1 and FIG. 1, one mover electrode portion 5 a formed on the U-shaped portion of the mover 5 is a convex portion at a predetermined pitch at a twist position in a direction orthogonal to the optical axis 1. The movable element electrode portion 5b formed on the other of the U-shaped portions is formed as a convex portion (three locations in the figure) in a direction parallel to the optical axis 1. Further, four protrusions 5d are formed on one side of the surface of the movable element 5 facing the stators 4a and 4b. The protrusion 5d is preferably formed at a position avoiding the electrode pattern formed on the stators 4a and 4b. Although not shown, the mover 5 is connected to wiring for removing charges.

  FIG. 3 is a schematic diagram showing electrode patterns formed on the stators 3a and 3b. 2A shows an electrode pattern formed on the surface of the stator 3a facing the mover electrode portion 5a shown in FIG. 2, and FIG. 2B shows the stator 3b shown in FIG. The electrode pattern formed in the surface facing the mover electrode part 5b is shown.

  As shown in the figure, the stator 3a is formed with four systems of electrodes A to D. The electrodes A to D are arranged as striped electrodes and viewed along the moving direction of the mover 5. They are arranged to appear in order. As will be described later, the four systems of electrodes A to D are used to move the mover 5 by sequentially switching and applying a voltage. Hereinafter, these electrodes A to D are referred to as drive electrodes.

  The relationship between the arrangement pitch of the stripe-shaped drive electrodes A to D and the pitch of the projections formed on the mover electrode portion 5a is that the width of the projection of the mover electrode portion 5a is L, and the arrangement pitch of the projections Assuming 2L (see FIG. 2), the arrangement pitch of the drive electrodes A to D is formed to be approximately L / 2.

  On the other hand, one line of electrode E is formed on the stator 3b at a position corresponding to the mover electrode portion 5b. Hereinafter, this electrode E is referred to as a holding electrode.

  The stators 3a and 3b are created by forming a conductor film on a substrate made of an insulator such as glass or ceramics by a technique such as sputtering. Moreover, it is preferable to provide an insulator film on the formed conductor film. Further, the driving electrodes A to D and the holding electrode E are connected to a switching circuit (not shown) for selectively applying a voltage to each electrode through a wiring pad, and a power source is connected to the switching circuit.

  FIG. 4 is a perspective view of the mover 6. This figure is a perspective view of the mover 6 from a direction different from that in FIG.

  As shown in FIG. 1 and FIG. 1, the mover electrode portion 6 a of the mover 6 is formed as a convex portion at a predetermined pitch at a twist position in the direction orthogonal to the optical axis 1, and the mover electrode portion 6 b is Projections are formed in the direction parallel to the optical axis 1 (two locations in the figure). Further, four protrusions 6d are formed on one side of the side surface of the mover 6. Although not shown, the mover 6 is connected to wiring for removing charges.

  FIG. 5 is a schematic view showing electrode patterns formed on the stators 4a and 4b. 4A shows an electrode pattern formed on the surface of the stator 4a facing the mover electrode portion 6a shown in FIG. 4, and FIG. 4B shows the stator 4b shown in FIG. The electrode pattern formed on the surface facing the mover electrode portion 6b is shown.

  As shown in the figure, four lines of electrodes G to J are formed on the stator 4a, and these electrodes G to J are arranged as striped electrodes and viewed along the moving direction of the mover 6. They are arranged to appear in order. These four systems of electrodes G to J are used to move the mover 6 by sequentially switching and applying a voltage, as will be described later. Hereinafter, the electrodes G to J are referred to as drive electrodes.

  The relationship between the arrangement pitch of the stripe-shaped drive electrodes G to J and the pitch of the convex portions formed on the mover electrode portion 6a is that the width of the convex portion of the mover electrode portion 6a is N, and the arrangement pitch of the convex portions. Assuming 2N (see FIG. 2), the arrangement pitch of the drive electrodes G to J is formed to be approximately N / 2.

  On the other hand, one line of electrode K is formed on the stator 4b at a position corresponding to the mover electrode portion 6b. Hereinafter, this electrode K is referred to as a holding electrode.

  The stators 4a and 4b are formed by forming a conductor film on a substrate made of an insulator such as glass or ceramics by a technique such as sputtering as described above. Moreover, it is preferable to provide an insulator film on the formed conductor film. Further, the driving electrodes G to J and the holding electrode K are connected to a switching circuit (not shown) that selectively applies a voltage to each electrode, and a power source is connected to the switching circuit. This switching circuit is a circuit different from the circuit connected to the stators 3a and 3b, whereby the stators 3a, 3b and 4a, 4b can be driven independently.

  Furthermore, the arrangement pitch of the stripe-shaped drive electrodes A to D shown in FIG. 3A is set smaller than the arrangement pitch of the stripe-like drive electrodes G to J shown in FIG.

  FIG. 6 is a view showing a cross section of the optical device according to the embodiment of the present invention, taken along a plane perpendicular to the optical axis. This figure is a cross-section cut at the U-shaped part of the mover 5 and the overlapping part of the mover 6. The mover 5 is sucked by the stator 3 b and the mover 6 is sucked by the stator 4 b and held. It is the state of being done.

  In the figure, reference numeral 8 denotes a casing, and the casing 8 holds a mounting substrate on which the stators 3a, 3b and 4a, 4b and the image pickup device are mounted.

  As shown in the figure, the stators 3a, 3b and 4a, 4b are arranged in a rectangular tube shape so as to surround the optical axis 1 of the optical system, and the lens group 5c is assembled by the stators 3a, 3b. The mover 5 is driven, and the mover 6 assembled with the lens group 6c is driven by the stators 4a and 4b.

  The interval between the stators 3a and 3b is set so that the movable element 5 has a gap d1 that can be sucked and adsorbed from both sides within the interval. The interval between the stators 4a and 4b is set so that the movable element 6 has a gap d2 that can be sucked and sucked from both sides within the interval.

  Further, the protrusion 5d of the mover 5 can be smoothly slid at a position avoiding the electrode patterns of the stators 4a and 4b, and the mover 5 moves between the stators 3a and 3b (X direction in the drawing). ) Is supported by the protrusion 5d.

  On the other hand, the mover 6 enters between the U-shaped portions of the mover 5 and is set to have a gap d3 with respect to the interval inside the U-shaped portion. The gap d3 is preferably set to be the same as d1 described above, but may be set to be slightly larger than d1. By setting in this way, even if the mover 5 is sucked and moved from both the stators 3a and 3b, the mover 6 can be prevented from being affected by the movement of the mover 5.

  Next, the movement control method of the mover in the optical axis direction will be described with reference to FIGS.

  FIG. 7 is a schematic diagram showing a cross section of the stators 4a, 4b and the mover 6 cut along the optical axis. FIG. 8 is a time chart showing a sequence when the movable element 6 is driven by the drive electrodes G to J formed on the stator 4a and the holding electrode K formed on the stator 4b. FIG. 9 is a diagram showing an operating state of the mover 6 corresponding to the time chart of FIG.

  As already described, the arrangement pitch of the stripe-shaped drive electrodes G to J is formed to be ¼ of the pitch of the convex portions formed in the mover electrode portion 6a. Further, as shown in FIG. 7, the convex portion is at a position corresponding to the drive electrodes I and J, and a voltage is applied to the holding electrode K, and the movable element 6 is attracted to the stator 4b side. This state shows the state of the time axis t0 in the time chart shown in FIG.

  In FIG. 8, the voltage application to the holding electrode K is stopped at t1, and the voltage is applied to the drive electrodes H and I. As a result, the convex portion of the mover 6 is attracted to the drive electrodes H and I of the stator 4a, and as shown in FIG. 9 (a), the left-hand side of the drawing is inclined by one pitch of the drive electrodes formed on the stator 4a. Move up. That is, the mover 6 moves to the upper left (in the direction of the arrow in FIG. 9A).

  Next, voltage application to the drive electrodes H and I is stopped at time t2 in FIG. The mover 6 loses the suction force with the stator 4a, and moves downward (in the direction of the arrow) as shown in FIG. 9B by the suction force with the holding electrode K of the stator 4b. Accordingly, the mover 6 is moved from the state shown in FIG. 7 to the left side in the optical axis direction by one pitch of the drive electrodes formed on the stator 4a.

  Next, voltage application to the holding electrode K is stopped at t3 in FIG. 8, and voltage is applied to the drive electrodes G and H. The convex portion of the mover 6 is attracted by the drive electrodes G and H of the stator 4a, and as shown in FIG. 9 (c), the drive electrode 1 formed on the stator 4a is further inclined by one pitch. Move in the direction. That is, the mover 6 further moves to the upper left (in the direction of the arrow in FIG. 9C).

  Next, voltage application to the drive electrodes G and H is stopped at time t4 in FIG. The mover 6 loses the attractive force with the stator 4a, and moves downward (in the direction of the arrow) as shown in FIG. 9 (d) by the attractive force with the holding electrode K of the stator 4b. Thereby, the mover 6 is moved from the state shown in FIG. 7 to the left side of the paper in the optical axis direction by the pitch of the drive electrode 2 formed on the stator 4a.

  Thereafter, similarly, voltage application to the holding electrode K is stopped at t5, voltage application to the drive electrodes J and G is stopped, voltage application to the drive electrodes J and G is stopped at t6, voltage application to the holding electrode K, t7 The voltage application to the holding electrode K is stopped, the voltage is applied to the driving electrodes I and J, the voltage application to the driving electrodes I and J is stopped at t8, the voltage is applied to the holding electrode K, and the voltage to the holding electrode K is applied at t9. The voltage application is stopped, the voltage is applied to the drive electrodes H and I, the voltage application to the drive electrodes H and I is stopped at t10, and the voltage is applied to the holding electrode K, whereby the mover 6 is shown in FIG. From the state, the driving electrode 5 formed on the stator 4a is moved to the left side in the optical axis direction by 5 pitches.

  The above is the order of voltage application to the drive electrodes G to J and the holding electrode K. By repeating this operation, the mover 6 can be moved to the left side in the optical axis direction by an arbitrary amount.

  Further, in order to move the mover 6 in the opposite direction (right side of the drawing), it can be moved by applying the voltages to the drive electrodes G to J in the reverse order.

  For example, to move the mover 6 in the reverse direction (right side of the paper) from the state of t10 described above, the voltage application to the holding electrode K is stopped at t11, the voltage is applied to the drive electrodes I and J, and the drive is performed at t12. The voltage application to the electrodes I and J is stopped, the voltage application to the holding electrode K is stopped, the voltage application to the holding electrode K is stopped at t13, the voltage application to the drive electrodes J and G is applied, and the drive electrode J and G are applied to the drive electrode at t14. The voltage application is stopped, the voltage is applied to the holding electrode K, the voltage application to the holding electrode K is stopped at t15, the voltage application to the driving electrodes G and H is stopped, the voltage application to the driving electrodes G and H is stopped at t16, Apply voltage to the holding electrode K, stop applying voltage to the holding electrode K at t17, apply voltage to the driving electrodes I and H, stop applying voltage to the driving electrodes I and H at t18, and apply voltage to the holding electrode K Thus, the mover 6 is driven by the drive electrode 5 formed on the stator 4a. From pitch fraction only state that has moved to the left side in the optical axis direction, only the driving electrodes 4 pitches can be moved back to the right side.

  7 to 9, the movement control method of the mover 6 in the stators 4a and 4b has been described. However, the movement control method of the mover 5 in the stators 3a and 3b has the same configuration. If so, the movement control can be performed in the same manner as described above, and is omitted here.

  FIG. 10 is a diagram illustrating the zooming operation of the zoom optical system. This figure is a diagram showing the positional relationship between the lens group 5c and the lens group 6c with the left side of the drawing as the object side and the right side of the drawing as the image side, and FIG. (B) shows the wide angle end (wide end), (c) shows the intermediate angle of view (middle), and (d) shows the telephoto end (tele end).

  As shown in the figure, the lens group 5c arranged on the object side is extended to the object side most at the wide end and the tele end, and is located slightly on the image plane side from this position in the middle. The lens group 6c arranged on the image plane side from the lens group 5c moves from the wide end to the tele end so that the lens group 6c is sequentially extended toward the object side, and a zooming operation is performed.

  The hatching area shown in the figure is a focusing area, and the lens group 5c can move alone within the hatching area to perform focus adjustment.

  The focus adjustment can be performed by moving both the lens groups 5c and 6c or by moving only the lens group 6c. However, a method of moving only the lens group 5c arranged on the object side is as follows. Even if the focal length of the optical system is changed, focusing on the same subject distance with the same movement amount is most preferable.

  11 is a cross-sectional view of the optical device according to the embodiment of the present invention, taken along line FF shown in FIG. This figure is a diagram showing the positional relationship between the movable element 5 having the lens group 5c and the movable element 6 having the lens group 6c, with the left direction on the paper as the object side and the right side as viewed from the image side. (A) shows a degenerated (collapsed) state when not in use, (b) shows wide angle end (wide end), (c) shows intermediate angle of view (middle), and (d) shows (d). The telephoto end (tele end) is shown.

  As shown in FIG. 5A, the tips of the stators 3a and 3b are arranged so as to be substantially in the same position as the tip of the movable member 5 having the lens group 5c when retracted. Although not shown, the stators 4a and 4b are arranged on the front and back sides of the paper surface together with the stators 3a and 3b so as to form a square cylindrical shape, and the tip position is substantially the same as the tip position of the stators 3a and 3b or , So as to be located closer to the image plane side.

  Operations of degeneration (collapse) and zooming (magnification) of the optical device according to the embodiment of the present invention will be described with reference to FIG.

  From the retracted state shown in FIG. 5A, the stators 3a and 3b are driven using the above-described movement control method, and the mover 5 having the lens group 5c is extended to the position shown in FIG. It becomes the state of the wide end. At this time, the mover 6 is held by the holding electrode of the stator 4b.

  From the wide end shown in FIG. 6B to the middle shown in FIG. 5C, the stators 3a and 3b are driven to move the mover 5 to the position shown in FIG. The child 6 is driven into the middle state by driving the stators 4a and 4b to the position shown in FIG.

  From the middle shown in FIG. 4C to the tele end shown in FIG. 4D, the stators 3a and 3b are driven to move the mover 5 to the position shown in FIG. By driving the stators 4a and 4b to the position shown in FIG.

  Further, the focal length change from the tele end to the wide end needs to be driven so that the movable element 5 and the movable element 6 do not interfere with each other, but basically the reverse operation may be performed. Further, regarding the movement from the telephoto end or the middle to the retracted state, similarly, the retractable state is obtained by retracting the movable element 5 while retracting the movable element 6 in advance so that the movable element 5 and the movable element 6 do not interfere with each other. It can be. Further, only the mover 5 needs to be retracted from the wide end to the retracted state.

  As described above, the first stator pair (3a, 3b) and the second stator pair (4a, 4b) are arranged in a rectangular tube shape so as to surround the optical axis of the optical system. The first stator pair for driving the movable element having one lens group and the second stator pair for driving the movable element having the other lens group are arranged at substantially equal distances from the image plane. Thus, as described in the above-mentioned Patent Documents 1 and 2, the entire length of the optical device that conventionally required the length indicated by S in FIG. When not in use, it is possible to obtain an optical device using an electrostatic actuator that can be a length indicated by R and is small and thin in the optical axis direction in which the total length of the optical device is shortened.

  Further, since the two movers can be independently driven using the first stator pair (3a, 3b) and the second stator pair (4a, 4b), Regardless of the moving direction and moving amount of the mover, both of the two movers can be driven freely by simple control, and smooth zooming can be achieved. Furthermore, by moving both of the two movable elements simultaneously, it is possible to suppress the focus movement during zooming.

  Further, by varying the arrangement pitch of the drive electrodes between the stators 3a and 4a, the stop position accuracy of the lens group 5c disposed on the object side and the lens group 6c disposed on the image plane side during zooming can be increased. Can be optimized. In other words, since the lens group arranged on the object side has a small amount of movement during zooming, it is possible to set the position of the lens group more accurately by reducing the arrangement pitch of the drive electrodes of the stator that drives the lens group. Become. Further, when the lens group arranged on the object side is used for focusing, more accurate focusing can be performed with fine steps by this small arrangement pitch.

  In the embodiment, the first stator pair and the second stator pair have been described as an example in which the cross-sectional shape shown in FIG. 6 is arranged in a substantially square shape. Various modifications such as parallelograms and rectangles do not depart from the present invention.

  Further, the configuration of the individual electrodes of the stator and the drive control method are not limited to the above methods, and various methods such as those described in the above-mentioned patent documents can be applied. In addition, the configuration has been described in which only the object-side lens unit is moved from the retracted state to the wide state, but this is not a limitation, and the object-side lens unit and the image-side lens unit are different amounts. Needless to say, the present invention can also be applied to a configuration in which the lens unit is moved and moved so that the lens group can be photographed from the retracted state.

  In the above-described embodiment, the description has been given by taking the two-group zoom as an example. However, the present invention is not limited to this, and can be applied to a three-group zoom having a fixed lens group on the image plane side. A multi-group zoom in which two pairs of stators arranged so as to surround the optical axis are connected in series does not depart from the present invention.

  Furthermore, although the zoom lens has been described as an example, the present invention can also be applied as a so-called floating mechanism used at the time of close-up shooting of a single focus lens.

It is a disassembled perspective view which shows schematic structure of the optical apparatus which concerns on embodiment of this invention. 3 is a perspective view of a mover 5. FIG. It is the schematic which shows the electrode pattern formed in the stator 3a, 3b. 3 is a perspective view of a mover 6. FIG. It is the schematic which shows the electrode pattern formed in the stator 4a, 4b. It is the figure which showed the cross section which cut | disconnected the optical apparatus which concerns on embodiment of this invention by the surface perpendicular | vertical to an optical axis. It is a schematic diagram which shows the cross section which cut | disconnected stator 4a, 4b and the needle | mover 6 along the optical axis. 5 is a time chart showing a sequence in the case of driving the movable element 6 where the driving electrodes G to J formed on the stator 4a, the holding electrode K formed on the stator 4b, and the electrode connected to the movable element 6 are P. is there. It is a figure which shows the operation state of the needle | mover 6 corresponding to the time chart of FIG. FIG. 5 is a diagram illustrating a zooming operation of the zoom optical system. It is sectional drawing which cut | disconnected the optical apparatus which concerns on embodiment of this invention by the FF line | wire shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical axis 2 Image pick-up element 3a, 3b, 4a, 4b Stator 5, 6 Movable element 7 Mounting board 8 Case

Claims (4)

In an optical apparatus having an optical system having at least two moving lens groups that move independently in the optical axis direction, and an electrostatic actuator that moves the moving lens groups in the optical axis direction,
The electrostatic actuator has a pair of a first stator and a pair of a second stator, with a pair of two stators having electrodes arranged opposite to each other across the optical axis of the optical system. The first and second stator pairs are arranged to surround the optical axis of the optical system;
The first stator pair moves one moving lens group of the optical system, and the second stator pair moves the other moving lens group of the optical system. Optical device. The optical apparatus according to claim 1, wherein an arrangement pitch of electrodes formed on at least one of the pair of stators is different between the pair of the first and second stators. Of the first stator pair and the second stator pair, the arrangement pitch of the electrodes of the stator that moves the moving lens group arranged on the object side is smaller than the other arrangement pitch. The optical device according to claim 1 or 2. The optical apparatus according to claim 1, wherein focusing is performed by moving a moving lens group disposed on the object side.

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