JP4194145B2 - Imaging device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image pickup apparatus having a light amount adjusting device and a lens barrel driving device suitable for a retractable zoom camera.
[0002]
[Prior art]
Conventionally, for example, a device as shown in FIG. 18 has been proposed as a light amount adjusting device that changes the aperture diameter by sliding a plurality of light amount adjusting members.
[0003]
201 is a coil wound around a bobbin, 202 and 203 are yokes, and 204 is an arm integrally provided with a magnet 205. When this arm rotates, the light quantity adjusting members 206 and 207 are slid to drive the opening diameter. Change.
[0004]
Further, in recent years, an imaging apparatus having a solid-state imaging device such as a video camera or an electronic still camera has a rear focus lens for its miniaturization, and the lens driving means is usually circular. The step motor is used.
[0005]
[Problems to be solved by the invention]
In the conventional example of the light amount adjusting device, the magnetic circuit including the coil, the yoke, and the magnet is concentrated on the position deviated with respect to the optical axis, so that the layout of the lens barrel is limited. In particular, it is a hindrance to downsizing a lens group that is driven by a combination of cylindrical members, such as a collapsible zoom lens barrel that has become popular in recent years. It was.
[0006]
Further, there has not been proposed a small lens driving means or the like which is a rear focus type lens system and particularly suitable for a retractable zoom lens barrel.
[0007]
[Means for Solving the Problems]
  This applicationThe inventionIn an imaging device having a light amount adjusting device that adjusts the amount of light incident on the image plane and a lens barrel that houses the light amount adjusting device, the light amount adjusting device includes:Can slide in a direction perpendicular to the optical axisNaMultiple light quantity adjustment members and coils,yokeand,magnetOrMagnetic circuit and the magnetWithrotationMultipleAnd an arm for driving the light amount adjusting member..Coils and magnetsHowever, in the sliding direction of multiple light quantity adjustment membersOpposed to the optical axisHaveAnd,Magnetic circuitBut,Above slideExtending along the directionRu.
[0008]
  In this configuration,The light amount adjustment deviceEven if it is arranged inside and is configured to move in the optical axis direction, ImagingThe device can be arranged without increasing the size.
[0010]
  Invention of the present applicationConfigurationIn,A lens holding member that holds the lens and is movable in the optical axis direction, a feed screw having a screw portion that moves the lens holding member, a drive unit that rotationally drives the feed screw, and an image sensor holding member that holds the image sensor And as a driving means, a magnetic circuit comprising a magnet integrally provided on the feed screw, and a plurality of coils and yokes arranged linearly opposed across the magnet. it can. AndDriving meansMagnetic circuitImage sensorHolding memberBy arranging along one side,ImagingThe apparatus can be miniaturized and the integration density of components can be increased.
[0015]
  here, Light control deviceInLongitudinal direction of magnetic circuit and driving meansMagnetic circuit inBy matching the longitudinal direction, the total length when retracted is shortened,ImagingThe apparatus can be miniaturized.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
  FIG. 19 is a sectional view showing an optical arrangement according to the embodiment of the present invention. In this embodiment, in order from the object side, there are three lens groups, a first lens group having a negative refractive power, a second lens group having a positive refractive power, and a third lens group having a positive refractive power. When zooming from the wide-angle end to the telephoto end,lensReciprocating movement with the group convex toward the image side, secondlensThe group moves to the object side and the thirdlensThe group is moving during zooming.
[0019]
  This embodiment is basically a negative firstlensGroup and positive secondlensThe group constitutes a so-called wide-angle short zoom system.lensScaling by moving the group, negative firstlensThe movement of the image point accompanying zooming is corrected by reciprocating the group. Positive thirdlensThe group shares the increase in the refractive power of the photographing lens accompanying the downsizing of the image sensor.lensThe first is to reduce the refractive power of the short zoom system composed of groups.lensSuppressing the occurrence of aberrations in the lenses constituting the group and achieving good optical performance. In addition, the telecentric image formation on the image side necessary for a photographing apparatus using a solid-state image pickup device or the like is particularly positive third.lensThis is achieved by giving the group the role of a field lens.
[0020]
  Further, by placing the stop closest to the object side of the second lens group and reducing the distance between the entrance pupil on the wide angle side and the first lens group, the outer diameter of the lenses constituting the first lens group can be increased, and PositiveFirst2lensThe first across the aperture arranged on the object side of the grouplensGroup and thirdlensBy canceling off-axis aberrations with the group, good optical performance can be obtained without increasing the number of components.
[0021]
  Further, in the present embodiment, the negative firstlensThe group is composed of, in order from the object side, two concave lenses 4 and 5 having a concave surface directed toward the image side, and a convex lens 6 having a convex surface directed toward the object side, and a positive secondlensThe group is composed of three lenses of a convex lens 10, a concave lens 11, and a convex lens 12 in order from the object side.lensThe group consists of convex lenses.
[0022]
  Thus eachlensThe lens system is made compact while maintaining good performance by adopting a configuration in which the desired refractive power arrangement and aberration correction are compatible. Negative firstlensThe group has the role of focusing the off-axis chief ray on the center of the aperture, and on the wide-angle side, the off-axis chief ray has a large amount of refraction, so there are various off-axis aberrations, especially astigmatism and distortion. It is easy to generate. Therefore, a concave-convex configuration that can suppress the increase of the lens diameter closest to the object side as in the case of a normal wide-angle lens is used, and the negative lenses that mainly share negative refractive power are refracted as two lenses of 4 and 5. We are trying to share power.
[0023]
  FirstlensEach lens constituting the group has a shape close to a concentric spherical surface centered on the stop center in order to suppress the occurrence of off-axis aberration caused by refraction of the off-axis principal ray. Positive secondlensThe group has a so-called triplet configuration. This moves a lotlensBecause of the group, due to manufacturing errorslensIn order to prevent manufacturing degradation due to eccentricity between groups,lensThis is because spherical aberration and coma aberration are removed to some extent by the group alone.First2lensThe most object side convex lens 10 in the group isFirst1lensThe off-axis chief ray emitted from the group is refracted greatly, and is convex toward the object side so that various off-axis aberrations do not occur. Further, the concave lens 11 has a concave surface on the image side, and a negative air lens is formed together with the convex surface of the subsequent convex lens 12 on the image side, thereby correcting spherical aberration that occurs as the aperture ratio increases. Positive thirdlensThe group also serves as a field lens for image side telecentricity.
[0024]
  Also, eachlensIn this embodiment, an aspherical surface is effectively introduced in order to achieve further improvement in optical performance while forming a group with a small number of sheets. In the embodiment shown in FIG.lensThe object side surface of the concave lens 4 constituting the group has an aspheric surface having a positive refracting power at the periphery, and astigmatism and distortion are corrected particularly on the wide angle side. ThirdlensThe object side surface of the convex lens constituting the group has an aspheric surface where the positive refracting power becomes weak at the periphery, which contributes to correction of various off-axis aberrations in the entire zoom range. As for the distortion aberration, barrel distortion at the wide-angle end usually becomes a problem.lensIn addition to the aspherical surface introduced into the group, correction is performed not only at the wide-angle end but also throughout the entire zoom range.
[0025]
When photographing a short-distance object using the zoom lens of the present embodiment, good performance can be obtained by moving the third lens group to the object side.
[0026]
Below, the numerical value of this Embodiment is shown.
[0027]
In the numerical example, i indicates the order of the surfaces from the object side, Ri is the radius of curvature of the lens surface, Di is the lens thickness and air spacing between the i-th surface and the i + 1-th surface, Ni, .nu.i. Indicates the refractive index and Abbe number for the d-line, respectively. The two surfaces closest to the image side are glass materials such as a face plate. B, C, D, E, and F are aspheric coefficients. An aspherical shape is when the displacement in the optical axis direction at the position of height h from the optical axis is x with respect to the surface vertex.
x = R {1- (1-h2 / R2) 1/2} + Bh4 + Ch6 + Dh8 + Eh10 + Fh12
It is represented by Where R is the radius of curvature.
[0028]
[Numerical Example 1]
This numerical embodiment is a zoom lens having a zoom ratio of 2.5 times and an aperture ratio of about 2.8 to 4.0. 19 is a cross-sectional view, FIGS. 20 to 22 are aberration diagrams, and FIG. 23 shows numerical examples.
[0029]
(One embodiment)
1 is an exploded perspective view of a lens barrel portion showing an embodiment of a camera embodying the present invention, FIGS. 2 to 4 are central sectional views, FIG. 2 is a retracted position, FIG. 3 is a wide position, and FIG. Indicates the position.
[0030]
Reference numeral 1 denotes a base which is a base portion of the lens barrel unit, and forms a structure of the lens barrel unit together with a fixed cylinder 2 fixed to the front end portion thereof by screws. Reference numeral 3 denotes a first group barrel, which holds the lenses 4, 5, and 6 shown in FIG. Three follower pins 7 having a tapered portion at the tip are press-fitted on the outer peripheral side surface, and a cap 8 is fixed to the front surface by adhesion.
[0031]
Reference numeral 9 denotes a second group barrel, which holds the lenses 10, 11, and 12 and is integrally held on the diaphragm base plate 14 of the diaphragm unit 13 by means such as adhesion.
[0032]
FIG. 5 is an exploded perspective view of the aperture unit 13. In the outer peripheral portion of the aperture base plate 14, two follower portions 14 a each having a tapered portion at the tip are integrally formed and are provided movably in the axial direction. One movable follower 81 is provided, and a total of three followers are equally arranged. The rear end of the movable follower 81 is pressed and urged by a leaf spring 82, whereby the mechanical gap is shifted to maintain accuracy. Here, the movable follower 81 is provided in the uppermost position among the three followers when the camera is in the normal position, so that the direction of gravity and the direction of gravity substantially coincide with each other with a small biasing force. A sufficient displacement effect can be obtained. A space-saving effect can be obtained and the driving load can be reduced.
[0033]
Reference numeral 83 denotes a coil wound around a bobbin. Magnetic flux generated by energizing the coil generates magnetic rotational force in a magnet 87 formed integrally with the arm 86 via yokes 84 and 85.
[0034]
Reference numerals 88 and 89 denote light quantity adjusting members, and linear long hole portions 88b to 88d and 89b to 89d provided respectively are guided by the shafts 14b to 14e of the main plate 14 so as to be slidable. Further, two shaft portions 86 a and 86 b provided on the arm portion of the arm 86 are inserted into the holes 88 a and 89 a of the light amount adjusting members 88 and 89.
[0035]
Reference numeral 90 denotes a cap, which fixes the coil 83 and the yokes 84 and 85 between the base plate 14 and holds the arm 86 (and the magnet 87) rotatably. Reference numeral 91 denotes a case for preventing the light amount adjusting members 88 and 89 from falling off.
[0036]
  The aperture unit 13 is disposed on the inner periphery of a straight guide cylinder 49 described later. Therefore, a coil 83 that requires a certain space in the unit and a magnet87Are arranged separately on both sides of the optical axis, and in particular, by making the longitudinal direction thereof coincide with the sliding direction of the light amount adjusting members 88 and 89, the arrangement is suitable for the inside of a cylindrical part such as the linear guide cylinder. And contributes to the miniaturization of the device.
[0037]
Reference numeral 15 denotes a third group barrel holding the lens 16, which is guided by guide bars 17 and 18 extending in the optical axis direction, and its axial position is regulated by a nut 19 having a female screw held between its arm portions, The tension spring 20 is offset in the retraction direction. Further, as shown in FIG. 7, a projection 15a of the third group lens barrel 15 is fitted in the slit portion 19a provided in the nut 19, and the rotation is restricted.
[0038]
Reference numeral 21 denotes a screw provided integrally with the magnet 22, and has a male screw portion that is screwed with the female screw portion of the nut 19. Reference numeral 23 denotes a bearing metal press-fitted into the base 1, and one end of the screw 21 is rotatably fitted therein.
[0039]
Reference numeral 24 denotes a stepping motor for driving the third group lens barrel 15. As shown in FIG. 6, a pair of yokes 25 and 26 and a coil 27 wound around a bobbin are arranged in two pairs with the magnet 22 interposed therebetween. It arrange | positions so that it may oppose linearly, and is fixed by screwing the yoke plate 28 on the base 1. As shown in FIG.
[0040]
Reference numeral 29 denotes a photo interrupter fixed to the base 1, and a slit plate 30 fixed integrally to the third group lens barrel 15 is disposed at a position where it can be advanced and retracted to the slit portion of the photo interrupter.
[0041]
Reference numeral 31 denotes a cap fixed to the base 1, which fixes the distal ends of the guide bars 17 and 18 and holds the screw 21 rotatably.
[0042]
Reference numeral 32 denotes an image pickup element, which is fixedly held by adhesion or the like on a holding plate 33 fixed to the base 1 with screws. Reference numeral 34 denotes a flexible circuit that supplies the photoelectrically converted image signal to a signal processing circuit described later. 35 is a dust-proof rubber, and 36 is a low-pass filter (LPF), both of which are fixed to the base 1 by adhesion or the like. In a state where the image pickup device 32 is fixed to the base 1, the image pickup device 1, the rubber 35, and the low-pass filter 36 are held by the holding portion 1 ′ of the base 1 provided around the image pickup device 32, and along one side of the holding portion 1 ′. A magnetic circuit of the motor 24 including a coil 25, a yoke, and a magnet is disposed.
[0043]
A driving ring 37 is rotatably fitted to the outer peripheral portion of the fixed cylinder 2. As shown in FIG. 8, a gear portion 37 a is partly provided on the outer peripheral portion of the drive ring 37. Reference numeral 38 denotes a DC motor, and a pinion gear 39 is integrally provided on the output shaft by press fitting or the like. The driving force of the motor 38 is transmitted from the gear 39 to the gear portion 37a of the driving ring 37 via gears 40, 41, 42, 43, 44, 45 in order. These gears 40 to 45 are housed in gear boxes 46 and 47 and are fixed to the base 1. The motor 38 is also fixed to the gear box 46.
[0044]
A movable cam ring 48 is fitted to the inner peripheral portion of the fixed cylinder 2, and a rectilinear guide cylinder 49 is fitted to the inner periphery thereof. A drive pin 50 and a follower pin 51 having a tapered portion are planted equally on the outer peripheral portion of the movable cam ring 48, and the drive pin 50 penetrates the hole 2 a of the fixed cylinder 2 and is connected to the drive ring 37. It fits into a groove 37b provided on the inner peripheral side.
[0045]
Further, as shown in FIG. 9, the follower pin 51 is in sliding contact with a tapered cam groove 2 b provided on the inner periphery of the fixed cylinder 2. FIG. 9 is an inner surface development view for explaining the above.
[0046]
Also, in the inner surface development view of the movable cam ring 48 shown in FIG. 10, tapered cam grooves 48a and 48b are provided on the inner periphery thereof, and the followers 7 and 14a (or 81) are in sliding contact with each other. At the same time, the side surface portion of each follower is fitted into the linear grooves 49a and 49b of the linear guide tube 49, and the position in the rotational direction is restricted.
[0047]
Further, the front protrusion 49c on the outer periphery of the straight guide tube 49 is in contact with the groove 48c on the inner periphery of the moving cam ring, and the flange portion 49d on the rear end is in contact with the end of the moving cam ring. As a result, the linear guide cylinder is restricted from moving relative to the moving cam ring in the optical axis direction. At the same time, the rear protrusion 49e is fitted in the linear groove 2c on the inner periphery of the fixed cylinder 2 so as to be able to advance straight, and movement in the rotational direction is restricted.
[0048]
As shown in FIGS. 1 to 6, the step motor 24 is developed in a straight line along one side at substantially the same height as the image pickup device 32 and the LPF 36, and near the center of the one side. A screw 21 and a magnet 22 are arranged on the surface. As a result, the third group lens barrel 15 can be made thin in a flat plate shape, and cylindrical parts such as the movable cam ring 48 and the rectilinear guide cylinder 49 can be arranged close to each other, thereby reducing the size of the apparatus.
[0049]
Further, by aligning the longitudinal direction of the aperture unit 13 with the longitudinal direction of the step motor 24, the guide bars 17, 18 and the screw 21 are formed around the aperture unit and inside the movable cam ring 48. As shown in FIG. 2, the total length of the apparatus when retracted can be shortened.
[0050]
1-4, 52 is a cap, which holds a dustproof sheet 53 between the fixed cylinder 2 and rails 52a and 52b for guiding a barrier 54 described later on the front surface thereof. A dustproof sheet 55 is also inserted into the groove 48c of the moving cam ring.
[0051]
  FigureIn 12, 56 is a linear sensor, which is fixed to the base 1 by screws or the like. The circuit configuration is composed of a variable resistor as shown in FIG. 11A, and when the slider 56a is slid, the output changes linearly as shown in FIG. 11B. Reference numeral 57 denotes a lever for holding the slider 56a between the arm portions 57a and is guided by the guide bar 58.
[0052]
The lever 57 has a follower portion 57 b having a tapered portion at the tip, and its side surface is fitted in the groove portion 1 a of the base 1. Reference numeral 59 denotes a spring for biasing the lever. In addition, FIG. 12 is the figure which looked at this part from the front.
[0053]
  FIG. 13 is a developed view of the outer surface of the drive ring 37, and the follower portion 57b of the lever is in sliding contact with the linear cam groove 37c. 37d,37eIs a taper cam groove for zooming a finder lens (not shown), 60 is a follower unit provided integrally with a compensator lens (not shown), and 61 is a follower unit provided integrally with a variator lens (not shown). Are in sliding contact with the cam grooves 37d and 37e, respectively.
[0054]
1 and 14, the barrier 54 is rotatably supported around a shaft 63 planted on the barrier base 62, and is viewed from the front of the apparatus by a closing spring 64 hung on the hook portion 54 a of the barrier 54. Is biased in the direction.
[0055]
Reference numeral 65 denotes a barrier drive lever which is rotatably supported around a shaft 66 planted on the barrier base 62. An opening spring 67 is hooked on the hook portion 65a and is urged clockwise. Here, the spring force of the two springs is set as “closing spring 64 << opening spring 67”.
[0056]
A shaft 68 is planted at one end of the barrier drive lever 65 at a position corresponding to one side surface of the barrier 54. Reference numeral 69 denotes a leaf switch provided by integral molding, which is fixed to the barrier base 62 with screws. The barrier base 62 is fixed to the base 1 with screws.
[0057]
FIG. 14A shows a state in which the barrier is closed. When the stepped portion 37 f of the drive ring 37 contacts the bent portion 65 b of the barrier drive lever 65, the barrier drive lever 65 is opened and biased by the spring 67. It is locked in a state of being counterclockwise rotated. The barrier 54 is rotated in the closing direction by the urging force of the closing spring 64, and the bent portion 54 b abuts against the stopper portion 2 d of the fixed cylinder 2 and is in a closed state.
[0058]
FIG. 15 is a block diagram showing the electrical coupling of the camera embodying the present invention. The lens barrel 71 has been described above, and the constituent elements included in the figure are given the same reference numerals as above.
[0059]
The image signal photoelectrically converted by the image pickup device 32 is subjected to predetermined processing such as color conversion and gamma processing by the signal processing circuit 72 and then recorded in a memory 73 such as a card type recording medium. The control unit 74 controls the entire camera, and controls the step motor 24, the DC motor 38, and the aperture unit 13 while monitoring the outputs of the linear sensor 56, the photo interrupter 29, the leaf SW 69, and the like inside the lens barrel. The signal processing and memory control are also performed.
[0060]
Reference numeral 75 denotes an electrically erasable / recordable nonvolatile memory such as an EEPROM. Reference numeral 76 denotes a mode dial switch, which can switch and set each function mode such as power-off, shooting mode, playback mode, PC connection mode, and the like.
[0061]
The operation of the above configuration will be described below.
[0062]
When the DC motor 38 is driven, the drive ring 37 is rotated via the gears 39 to 45 as described above (FIG. 8), and the moving cam ring 48 is rotated via the drive pin 50, but via the follower pin 51. Therefore, it moves along the cam 2b of the fixed cylinder 2 and also moves in the optical axis direction (FIG. 9). When the movable cam ring 48 moves in the optical axis direction, the rectilinear guide tube 49 also moves in the optical axis direction. However, since the outer peripheral projection 49e is restricted by the fixed tube groove 2c, it does not rotate in the optical axis direction. Only move.
[0063]
When the movable cam ring 48 rotates, the first group barrel 3 and the second group barrel fixed to the aperture unit 13 are lifted by the cams 48a and 48b of the movable cam ring 48 along the grooves 49a and 49b of the straight guide cylinder, respectively. Accordingly, it moves relatively in the optical axis direction (FIG. 10).
[0064]
16A and 16B are diagrams in which only the locus of the cam portion is extracted. FIG. 16A shows the cam of the fixed barrel 2, FIG. 16B shows the first group barrel cam of the moving cam ring 48, and FIG. It is a cam. (D) is the movement trajectory of the first group barrel, which is the sum of (a) and (b), and (e) is the movement trajectory of the second group barrel, which is the sum of (a) and (c).
[0065]
W on the horizontal axis is a wide position, T is a tele position, S is a retracted position, and each cam is provided with a flat region from the retracted position S to a position indicated by B. Thus, the DC motor 38 is driven to switch between the retracted position and the shootable position and perform the zoom operation within the shooting range.
[0066]
When the drive ring 37 rotates, the finder lens (not shown) moves in the optical axis direction along the cams 37d and 37e via the followers 60 and 61 as described above, and interlocks with the zoom operation of the lens barrel.
[0067]
At the same time, the lever 57 moves in the optical axis direction along the cam 37c to displace the slider 56a of the linear sensor 56, and changes its output as shown in FIG. By detecting this output, the zoom position can be detected sequentially.
[0068]
As shown in FIG. 16D, the first group barrel depicts a locus that reciprocates convexly toward the image side between wide and telephoto. Therefore, by using non-linear cams between the three cams as described above, the gradient of each cam can be kept low, and the driving load can be reduced. Further, by providing both the cam (a) of the fixed barrel and the first group cam (b) of the movable cam ring so as to have a maximum value between the collapsed position and the wide position, the feeding amount of the first group barrel 3 can be set to the above two. The cams (a and b) can be dispersed, the total length of the fixed cylinder 2 and the movable cam ring 48 can be shortened, and the apparatus can be downsized.
[0069]
Further, as described above, when the drive ring 37 is retracted, the stepped portion 37f locks the barrier drive lever 65b (FIG. 14A). When released, the barrier drive lever 65 rotates clockwise by the biasing force of the opening spring 67 and presses the side surface of the barrier 54 via the shaft 68. Since the urging force of the closing spring 64 is weaker than the urging force of the opening spring 67 as described above, the barrier 54 is rotated counterclockwise to the open state shown in FIG. At this time, the bent portion 54b of the barrier 54 presses the segment 69a of the leaf switch 69, and the switch is turned on. Such an opening / closing operation of the barrier 54 is set to be completed in a flat region of each cam shown in S to B of FIG.
[0070]
When the step motor 14 is driven, the screw 21 rotates via the magnet 22. Since the nut 19 is restricted by the projection 15a of the third group barrel 15 as described above, the nut 19 moves in the optical axis direction, and the third group barrel also moves in the optical axis direction following this to adjust the focus. Within the range of the operation stroke of the third group lens barrel, the slit plate 30 enters or retreats into the slit portion of the photo interrupter 29 and switches its output. At this time, the counter is reset.
[0071]
FIG. 17 is a flowchart showing the operation of the camera, and FIG. When the shooting mode is selected with the mode dial 76 (s101), in s102, the control unit determines from the output of the linear sensor whether the zoom position of the lens barrel unit is the retracted position or the wide to tele shooting possible position. Determine.
[0072]
If the position is wide to tele, proceed to s107. If it is in the retracted position, the DC motor 38 is driven in the feeding direction by a predetermined amount in s103. This predetermined amount is an amount corresponding to S to B in FIG. 16 described above. Here, the zoom drive is temporarily stopped and it is detected whether or not the leaf switch 69 is on (s104).
[0073]
In s104, when the switch is off, it is considered that an error has occurred and a warning is displayed (s105). If it is on, the zoom is further driven to extend the lens barrel to the wide position (s106). .
[0074]
  After the zoom drive is completed, the next step motor in the direction of the switching position of the photo interrupter 2924Is driven (s107). When switching is detected, the position is stopped and the count is reset (s108). However, if it cannot be detected for some reason, a warning is displayed to indicate that an error has occurred, and zoom driving is simultaneously prohibited (s109). . When the reset operation is completed, the camera is further driven to a standby position where the focus operation is started to enter a standby state where photographing can be performed (s110).
[0075]
  FIG. 17B shows the end of the shooting mode. When the mode dial 76 selects a mode other than the shooting mode such as power off or playback mode (s111), the step motor is first used.24Is driven to move the third group barrel to the retractable standby position (s112). This position is adjusted in advance for each camera in the manufacturing process and stored in the nonvolatile memory 75. Next, the DC motor 38 is driven to move the lens barrel to the retracted position (s113), and the photographing mode is terminated (s114).
[0076]
  The state at this time is as shown in FIG. 2 as described above. As is apparent from FIGS. 2 to 4, the driving stroke of the third group barrel 15 at the photographing position is the second group barrel.9It overlaps with the retracted position.
[0077]
Therefore, as described above, the zoom driving is controlled first when shooting is started, and the third group lens barrel is always moved first to the retractable standby position when retracted, so that collision between the lens barrels is avoided. The distance between the lens barrels when retracted can be made extremely small. At the same time, if a malfunction occurs in the reset operation of the third group lens barrel, it is possible to avoid damage to the device by prohibiting the zoom operation.
[0078]
In general, the position where the photo interrupter is switched varies greatly, but by storing the retracted standby position in the memory as described above, the photo interrupter can be stored at an extremely small interval while avoiding a collision with the base 1.
[0079]
【The invention's effect】
  According to the present invention, the light amount adjusting device can be efficiently arranged in the lens barrel, and the imaging device can be downsized.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view of a lens barrel portion of a camera embodying the present invention.
2 is a central cross-sectional view (collapsed position) of the lens barrel of FIG. 1;
3 is a central sectional view of the lens barrel of FIG. 1 (wide position).
4 is a central sectional view (tele position) of the lens barrel of FIG. 1;
5 is an exploded perspective view of the aperture unit in FIG. 1. FIG.
6 is an exploded perspective view of the step motor unit of FIG. 1. FIG.
7 is a front view of the third group lens barrel drive unit of FIG. 1; FIG.
FIG. 8 is a diagram showing the zoom drive gear train of FIG. 1;
9 is a developed view of the inner surface of the fixed cylinder of FIG. 1. FIG.
10 is a developed view of the inner surface of the moving cam ring of FIG. 1. FIG.
FIG. 11 is a characteristic diagram of the linear sensor of FIG.
12 is a front view of the periphery of the linear sensor of FIG.
13 is a developed view of the outer surface of the drive ring of FIG. 1. FIG.
FIG. 14 is an explanatory diagram of the barrier opening / closing mechanism of FIG. 1;
15 is a block diagram showing an electrical configuration of a camera equipped with the lens barrel of FIG.
16A to 16E are views for explaining the cam of the lens barrel and the locus of the barrel in FIG. 1;
FIG. 17 is a flowchart showing a driving sequence of the lens barrel in FIG. 15;
FIG. 18 is a diagram showing a conventional light amount adjusting device.
FIG. 19 is a cross-sectional view showing an optical arrangement.
FIG. 20 is an aberration diagram.
FIG. 21 is an aberration diagram.
FIG. 22 shows aberration diagrams.
FIG. 23 is a diagram showing a numerical example.
[Explanation of symbols]
1 ... Base
2 ... Fixed cylinder
3 ... 1 group barrel
9 ... 2 group barrel
13 ... Aperture unit
15 ... 3 group lens barrel
24 ... Step motor unit
32 ... Image sensor
37 ... Drive ring
38 ... DC motor
48 ... Moving cam ring
49. Straight guide tube
54 ... Barrier
56: Linear sensor.

Claims (5)

In an imaging device having a light amount adjusting device that adjusts a light amount incident on an image plane and a lens barrel that houses the light amount adjusting device,
The light amount adjusting device is:
A plurality of light amount adjusting members slidable in a direction perpendicular to the optical axis;
Coil, a yoke and a magnet or Ranaru magnetic circuit,
An arm for driving the plurality of light amount adjusting member is rotated together with the magnet,
I have a,
Imaging apparatus said coil and said magnet, said plurality of oppositely disposed across the optical axis in the sliding direction of the light amount adjustment member Tei Rutotomoni, the magnetic circuit, characterized in that it extends along the sliding direction . A lens holding member that holds the lens and is movable in the optical axis direction ;
A feed screw having a screw part for moving the lens holding member ;
Drive means for rotationally driving the feed screw ;
And an image pickup element holding member for holding the IMAGING element,
Have
Said drive means includes a magnetic circuit consisting of a magnet integrally provided with a plurality of coils and a yoke disposed to face in a straight line across the magnet to said feed screw, the magnetic circuit imaging apparatus according to claim 1, characterized in that it is arranged along one side of the image pickup element holding member. Said drive means, in a state in which the lens holding member closest to the imaging element side, an imaging according to claim 2, characterized in that it is arranged at a position not to interfere in the lens holding member and the optical axis direction apparatus. 4. The image pickup apparatus according to claim 2 , wherein a longitudinal direction of the magnetic circuit in the light amount adjusting device is coincident with a longitudinal direction of the magnetic circuit in the driving unit. The barrel, an imaging apparatus according to any one of claims 1, characterized in that it is constituted from the collapsed position in the apparatus main body as feeds toward the photographing position 4.

Images