JP2007017846A - Lens barrel and camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a lens barrel constituted such that a lens frame is directly moved in a rectilinear advance by using a plurality of motors, and made inexpensive. <P>SOLUTION: In the lens barrel which has a plurality of lens groups and the plurality of motors, and where at least two lens groups of the plurality of lens groups are moved in an optical axis direction respectively by the plurality of motors, the plurality of motors are held by a single holding member. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a lens barrel having a plurality of lens groups for guiding subject light and configured to move at least two lens groups.

  2. Description of the Related Art Conventionally, cameras equipped with a variable focal length photographing lens (hereinafter also referred to as a zoom lens) are commercially available. In this zoom lens, the focal length is changed by moving a predetermined lens group of the plurality of lens groups constituting the optical system to a desired position along the optical axis and changing the distance between the lens groups. It has become.

  There are roughly two types of methods for moving a plurality of lens groups along the optical axis. A cam cylinder having a cam groove and a cam pin engaging with the cam groove are formed on the outer periphery of the lens frame. Engage with the linear guide and rotate the cam barrel to move the lens frame linearly, and place the shaft approximately parallel to the optical axis and use this axis as the guide axis for the linear guide. In some cases, a penetrating sleeve is formed, and a lens frame is directly slid along a guide shaft using a stepping motor and a lead screw.

  As an example of the latter lens barrel configured to move the lens frame linearly using a stepping motor, a lens barrel is disclosed in which a stepping motor is disposed in a substantially quadrangular barrel when viewed from the front (for example, Patent Document 1).

In addition, a lens barrel is disclosed in which a configuration in which a lens frame is linearly moved in a bending optical system is applied, and two lens groups are moved by two stepping motors (see, for example, Patent Document 2).
JP-A-8-313783 Japanese Patent Laying-Open No. 2003-222946 (FIG. 3)

  A lens frame that moves straight using a stepping motor does not require a complicated cam-shaped cam barrel or complicated lens barrel configuration, and is less expensive than a simple structure that uses a cam barrel. Therefore, it is most suitable for a lens barrel of a camera that does not require degeneration and is often used.

  The lens barrel that directly moves the lens frame straight using the stepping motors described in Patent Documents 1 and 2 is configured so that two stepping motors are individually incorporated in the lens barrel and fixed at a predetermined position. ing. In such an assembly configuration, generally, holding members for holding the stepping motor are each formed of a plate material, and the holding members are individually fixed to the lens barrel.

  In such a method, it is necessary to manufacture as many holding members as the number of motors, and jigs, parts costs, assembly costs, etc. are generated in proportion to the number of motors, which increases the cost. .

  In view of the above problems, an object of the present invention is to obtain a low-cost lens barrel in a lens barrel having a configuration in which a lens frame is directly moved linearly using a plurality of motors.

  The above problem is solved by the following configuration.

  1) It has a plurality of lens groups for guiding subject light and a plurality of motors, and at least two lens groups among the plurality of lens groups can be moved in the optical axis direction by the plurality of motors, respectively. A lens barrel, wherein the plurality of motors are held by a single holding member.

  2) The lens barrel according to 1), wherein the holding member also serves as a lid member of the lens barrel.

  3) The lens barrel according to 1) or 2), wherein the holding member is formed of a metal plate.

  4) A camera comprising the lens barrel according to any one of 1) to 3).

  According to the first aspect of the invention, in the lens barrel having a structure in which the lens frame is directly moved straight using a plurality of motors, even if the number of motors used is increased, jigs, parts costs, assembly costs are increased. Thus, a low-cost lens barrel can be obtained.

  According to the inventions 2) and 3), in addition to the above effects, the lens barrel can be formed thinner.

  According to the invention 4), a low-cost, thin camera equipped with a low-cost, thin lens barrel can be obtained.

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

  FIG. 1 is a diagram showing an example of an internal arrangement of main constituent units of a camera 100 including a lens barrel according to the present invention. FIG. 3 is a perspective view of the camera 100 as viewed from the subject side.

  As shown in the figure, in the camera 100, a lens barrel 50 according to the present invention including a foldable imaging optical system capable of zooming is arranged along the front surface as shown in the figure, and the opening 51 captures a subject light flux. Has been placed. Although not shown, a lens barrier that opens and closes the opening 51 is disposed.

  Reference numeral 52 denotes a flash light emission window. Reference numeral 53 denotes a flash unit including a reflector, a xenon tube, other main capacitors, a circuit board, and the like disposed behind the flash light emission window. Reference numeral 54 denotes a card-type image recording memory. A battery 55 supplies power to each part of the camera 100. The image recording memory 54 and the battery 55 can be inserted and removed from a lid (not shown).

  A release button 56 is arranged on the upper surface of the camera 100, and a shooting preparation operation, that is, a focusing operation and a photometric operation are performed by pushing the first button, and a shooting exposure operation is performed by pushing the second button. Reference numeral 57 denotes a main switch that switches the camera 100 between an operating state and a non-operating state. When switched to the operating state by the main switch 57, when a lens barrier is provided, the lens barrier is opened and the operation of each unit is started. When the main switch 57 is switched to the non-operating state, the lens barrier is closed and the operation of each unit is ended.

  On the back surface of the camera 100, an image display unit 58 that is configured by a display element such as an LCD or an organic EL and displays images and other character information is disposed. Although not shown, a zoom button for zooming up and down, a playback button for playing back a captured image, a menu button for displaying various menus on the image display unit 58, and a desired function are selected from the display. An operation member such as a selection button is arranged.

  Although not shown, each part is connected between these main constituent units and a circuit board on which various electronic components are mounted is arranged to drive and control each main constituent unit. Yes. Furthermore, an external input / output terminal, a strap attaching portion, a tripod seat, and the like (not shown) are provided.

  FIG. 2 is a schematic perspective view of a unit state of the lens barrel 50 according to the present embodiment. In addition, in the following figures, in order to avoid duplication of description, the same functional member will be given the same reference numeral.

  As shown in the figure, the outer surface of the lens barrel 50 has a substantially rectangular parallelepiped shape, and a plurality of lens groups (not shown) are arranged in the main barrel 9 and are movable among the plurality of lens groups. The first motor 20, the second motor 21, and the third motor 22 are provided for independently moving the three lens groups. Reference numeral 8 denotes an image sensor, and FPC is a flexible printed circuit board, which is connected to the image sensor 8 and a circuit board (not shown). Reference numeral 11 denotes a lens arranged closest to the object side, and is arranged with the optical axis OA facing the subject.

  As will be described in detail later, the first motor 20, the second motor 21, and the third motor 22 are fixed to the main body 9 while being integrally held by a single holding member 10. The first motor 20, the second motor 21, and the third motor 22 are, for example, stepping motors, which are connected to a printed circuit board (not shown) and individually controlled and driven.

  FIG. 3 is a cross-sectional view showing a foldable imaging optical system capable of zooming, which is included in the lens barrel 50 according to the present embodiment. FIG. 4A is a cross-sectional view taken along a plane including two optical axes before and after bending. FIG. 4B is a movement diagram of each lens group during zooming.

  As shown in FIG. 2A, OA is the optical axis before bending, and OB is the optical axis after bending. Reference numeral 1 denotes a first lens group. The first lens group 1 includes a prism 11 that is a reflection member that bends the optical axis OA in a substantially right angle direction, a lens 11 that is disposed toward the subject with the optical axis OA, and a prism 12. The lens 13 is disposed with the optical axis OB bent by the optical axis as the optical axis. The first lens group 1 is a lens group fixed to the main body 9.

  Reference numeral 2 denotes a second lens group, which is incorporated in the second lens group frame 2k. The second lens group is a lens group that moves together with the second lens group frame 2k during zooming (hereinafter also referred to as zooming).

  Reference numeral 3 denotes a third lens group, which is fixed to the main body 9. The third lens group 3 is a lens group that does not move.

  Reference numeral 4 denotes a fourth lens group, which is incorporated in the fourth lens group frame 4k. The fourth lens group is a lens group that moves together with the fourth lens group frame 4k during zooming.

  Reference numeral 5 denotes a fifth lens group, which is incorporated in the fifth lens group frame 5k. The fifth lens group is a lens group that moves integrally with the fifth lens group frame 5k during zooming.

  Reference numeral 6 denotes a sixth lens group, which is fixed to the main body 9. The sixth lens group 6 is a lens group that does not move.

  Reference numeral 7 denotes an optical filter in which an infrared light cut filter and an optical low-pass filter are stacked, and is assembled to the main cylinder 9. Reference numeral 8 denotes an image sensor, and a CCD (Charge Coupled Device) type image sensor, a CMOS (Complementary Metal-Oxide Semiconductor) type image sensor, or the like is used. The image sensor 8 is assembled to the main body 9. The FPC is a flexible printed circuit board that is connected to the image sensor 8 and connected to other circuits in the camera. S is an aperture shutter unit, which is fixed to the main cylinder 9.

  As shown in FIG. 4B, the first, third, and sixth lens groups are fixed lens groups, and the second, fourth, and fifth lens groups are between wide (W) and tele (T). The zooming is performed by moving as shown. The fifth lens group is further moved from the position moved by zooming to perform forcing.

  FIG. 4 is a plan view showing a schematic structure inside the main barrel 9 of the lens barrel 50 according to the present embodiment. This figure shows the inside of the lens barrel 50 shown in FIG. 2 with the first motor 20, the second motor 21, the third motor 22 and the holding member 10 holding them removed.

  As shown in the figure, inside the lens barrel 50, a sleeve 2s formed integrally with the second lens group frame 2k, a sleeve 5s formed integrally with the fifth lens group frame 5k, and the first A guide shaft 15 is provided through a rotation locking portion 4m formed integrally with the four-lens group lens frame 4k. Furthermore, a rotation locking portion 2m formed integrally with the second lens group frame 2k, a sleeve 4s formed integrally with the fourth lens group frame 4k, and integrally formed with the fifth lens group frame 5k. A guide shaft 16 is provided so as to penetrate through the formed rotation locking portion 5m. Thereby, the second lens group lens frame 2k, the fourth lens group lens frame 4k, and the fifth lens group lens frame 5k are slidable along the guide shafts 15 and 16 in the optical axis OB direction. Each sleeve is fitted with a guide shaft, and the guide shafts 15 and 16 are disposed substantially in parallel with the optical axis OB, and are fixed to the main body 9 by bonding or the like at both ends thereof.

  The sleeve 2s, the sleeve 4s, and the sleeve 5s are engaged with a lead screw formed integrally with the motor, slide along the guide shafts 15 and 16 by the rotation of the lead screw, and move in the direction of the optical axis OB. Engagement members 23, 24, and 25 are assembled.

  Reference numerals 32, 34, and 35 denote photo interrupters. The photo interrupter 32 detects the initial position for positioning the second lens group frame 2k by detecting the switching position of the presence or absence of the shielding portion formed on the second lens group frame 2k. The photo interrupter 34 detects the initial position for positioning the fourth lens group frame 4k by detecting the switching position of the presence or absence of the shielding portion formed on the fourth lens group frame 4k. The photo interrupter 35 detects an initial position for positioning the fifth lens group frame 5k by detecting a switching position of the presence or absence of a shielding portion formed on the fifth lens group frame 5k.

  The rotation direction and amount of rotation of the first motor 20, the second motor 21, and the third motor 22 are independently controlled based on this initial position, and the position control of each lens group is performed. The initial position detection of each lens group lens frame may be a photo reflector.

  Hereinafter, the holding member that holds the motor according to the present embodiment will be described in more detail.

  FIG. 5 is a diagram illustrating a unit state of the first motor 20, the second motor 21, the third motor 22, and the holding member 10 according to the present embodiment that holds these.

  FIG. 6 is a schematic cross-sectional view showing the motor holding state of the holding member 10.

  As shown in FIG. 5, the holding member 10 integrally holds the first motor 20, the second motor 21, and the third motor 22. First, a fixing method to the holding member 10 will be described using the first motor 20 as an example.

  As shown in FIG. 6, the holding member 10 is formed with bent portions 10m and 10n corresponding to the respective motors, and further, holes are formed in the bent portions 10m and 10n.

  The case of the first motor 20 and the bent portion 10m are fixed by spot welding, for example. The first motor 20 has a lead screw portion 20r that is substantially coaxial with the rotation shaft. A bearing 31 is disposed at the tip of the lead screw 20r, and the bearing 31 is inserted into a hole formed in the bent portion 10n. The fixing of the motor case and the bent portion is not limited to welding, but may be fixed by bonding, screwing, or the like.

  With the configuration as described above, the first motor 20 is held by the holding member 10, and the lead screw portion 20r is rotated by a predetermined electrical input to the first motor 20. The second motor 21 and the third motor 22 are also integrally held by the holding member 10 in the same manner.

  As shown in FIG. 5 and FIG. 6, by holding a plurality of motors with a single holding member, as many holding members as the number of motors of the conventional configuration are manufactured, jigs, parts costs, assembly costs. It is possible to obtain a lens barrel that is lower in cost than a configuration that requires the above.

  Further, in a state where the first motor 20, the second motor 21, and the third motor 22 are held by the holding member 10 shown in FIG. 5, the two holes 36a formed in the holding member 10 and the main trunk shown in FIG. The main cylinder 9 and the holding member 10 are positioned by the two bosses 36b formed in 9, and formed in the four holes 37a formed in the holding member 10 shown in FIG. 5 and the main cylinder 9 shown in FIG. The holding member 10 is fixed by screws at the four holes 37b.

  Note that the two notches 10k due to the bent portion 10n formed in the holding member 10 prevent dust from entering the lens barrel 50 when the holding member 10 is assembled to the main barrel 9. Therefore, it is desirable to cover with tape or the like.

  FIG. 7 is a diagram showing a schematic cross-section of a state in which the holding member 10 holding a plurality of motors is assembled to the main body 9. This figure is a view of the second lens group frame 2k as seen from the image plane side.

  As shown in the figure, the second lens group frame 2k holding the second lens group 2 is integrally formed with a sleeve 2s and a rotation locking portion 2m, and a guide shaft 15 is fitted into the sleeve 2s. The guide shaft 16 is engaged with the rotation locking portion 2m. Further, an engagement member 23 is assembled to the sleeve 2s and is engaged with the lead screw 20r of the first motor 20.

  The fourth lens group lens frame 4k and the lead screw 22r of the third motor 22 and the fifth lens group lens frame 5k and the lead screw 21r of the second motor 21 have the same configuration.

  That is, the holding member 10 holds a plurality of motors and also serves as a lid member that closes the opening of the main cylinder 9 when assembled to the main cylinder 9. In this way, the lens barrel 50 can be made thinner as shown in the figure by also using the lid member. In order to form the lens barrel 50 thinner, the holding member 10 is preferably formed of a metal plate that is thin but excellent in strength, but may be formed by resin molding.

  When the holding member 10 is made of metal, it is desirable to prevent reflection by coating, flocking or flocking a sheet, surface treatment such as plating, antireflection tape or the like on at least the inner surface.

  FIG. 8 is an enlarged view of an engaging portion that engages with the lead screw 20 r of the engaging member 23.

  As shown in the figure, when the holding member 10 is assembled to the main body 9, the lead screw 20 r of the first motor 20 is sandwiched between the pressing portion 23 p and the protruding portion 23 t formed on the engaging member 23. It becomes the state. The pressing portion 23p presses the lead screw 20r in the direction of the arrow shown in the figure, and the projection 23t is formed so as to enter the valley of the lead screw 20r.

  As a result, when the lead screw 20r of the first motor 20 rotates, the second lens group frame 2k with the engaging member 23 assembled is guided by the guide shafts 15 and 16 and moved in the direction of the optical axis OB. Can do. In addition, the engaging portion where the engaging member 25 and the lead screw 21r of the second motor 21 are engaged and the engaging portion where the engaging member 24 and the lead screw 21r of the third motor 22 are engaged have the same configuration. is there.

  In this embodiment, an example in which three motors for driving the lens group are used has been described. However, the present invention is not limited to this, and the effect of the present invention can be obtained when there are two or more motors. In addition, the lens barrel 50 has been described as an example of a barrel containing a bent optical system, but the present invention is not limited to this, and can be applied to a lens barrel containing an optical system having a normal linear optical axis. Yes.

It is a figure which shows an example of the internal arrangement | positioning of the main structural unit of the camera provided with the lens barrel which concerns on this invention. It is a schematic perspective view of the unit state of the lens barrel according to the present embodiment. 1 is a cross-sectional view illustrating a foldable imaging optical system that is variable in magnification and is contained in a lens barrel according to the present embodiment. It is a top view which shows schematic structure inside the main cylinder of the lens barrel which concerns on this Embodiment. It is a figure which shows the unit state of the holding member which concerns on a 1st motor, a 2nd motor, a 3rd motor, and this Embodiment holding these. It is a cross-sectional schematic diagram which shows the motor holding state of a holding member. It is a figure which shows the schematic cross section of the state by which the holding member holding the some motor was assembled | attached to the main trunk | drum. It is an enlarged view of the engaging part engaged with the lead screw of an engaging member.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st lens group 2 2nd lens group 2k 2nd lens group frame 3 3rd lens group 3k 3rd lens group frame 4 4th lens group 4k 4th lens group frame 5 5th lens group 5k 5th lens Group lens frame 6 Sixth lens group 7 Optical filter 8 Image sensor 9 Main cylinder 10 Holding member 15, 16 Guide shaft 20 First motor 21 Second motor 22 Third motor 50 Lens barrel 100 Camera

Claims (4)

A lens having a plurality of lens groups for guiding subject light and a plurality of motors, wherein at least two lens groups of the plurality of lens groups are respectively movable in the optical axis direction by the plurality of motors. In the lens barrel,
A lens barrel, wherein the plurality of motors are held by a single holding member. The lens barrel according to claim 1, wherein the holding member also serves as a lid member of the lens barrel. The lens barrel according to claim 1, wherein the holding member is formed of a metal plate. A camera comprising the lens barrel according to claim 1.

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