JP2007271648A - Lens barrel and imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens barrel, having small individual difference dispersions and satisfactory imaging performance in the lens barrel constituted of a housing, divided into an object side and an image face side of the optical axis. <P>SOLUTION: In the lens barrel included in an imaging optical system, having a plurality of lens groups, has a part of a mirror frame for holding the lens group that is arranged in the inside of a housing in the outside of the housing exposed, and is for adjusting the position of the orthogonal direction of the optical axis of the lens group held on the mirror frame. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a lens barrel that houses an imaging optical system and an imaging apparatus that includes the lens barrel.

  Conventionally, cameras equipped with a zoom lens are commercially available. The zoom lens is configured to change the focal length (zooming) by moving a plurality of lens groups constituting the optical system to a desired position along the optical axis and changing the interval therebetween.

  On the other hand, a camera having a so-called bending optical system in which a reflecting surface is disposed in an optical system and an optical axis is bent is known. A camera provided with this bending optical system has an advantage that the lens barrel does not protrude from the front of the camera at the time of shooting, and the form of the camera does not change even when zooming is performed.

As the structure of the lens barrel that houses such a bending optical system, it is a case that is divided into an object side and an image surface side of the optical axis after being bent by the reflecting surface, and after incorporating a lens group in each case, There is a lens barrel that is coupled with a casing (see, for example, Patent Document 1).
Japanese Patent Laying-Open No. 2005-121882 (FIGS. 8 and 9)

  In the case of the lens barrel having the configuration described in Patent Document 1, since the imaging optical system is divided and assembled before and after the optical axis direction, the casings are combined and integrated. There is a problem in that variation in individual imaging performance increases due to component errors and attachment errors between bodies.

  Furthermore, there is a high demand for downsizing of the imaging optical system and the lens barrel, and if the downsizing of the imaging optical system is corresponding to this, the allowable shift amount with respect to the optical axis of a specific lens group constituting the imaging optical system is very large. The above problem becomes more pronounced as it becomes smaller.

  In view of the above problems, the present invention provides good imaging performance with little variation in individual differences in imaging performance even with a lens barrel composed of a housing divided into an object side and an image plane side of the optical axis. It is an object of the present invention to obtain a lens barrel having an image pickup apparatus that can capture an image with good image quality.

  The above object is achieved by the invention described below.

  1. In a lens barrel containing an imaging optical system having a plurality of lens groups, a part of the lens frame holding the lens group arranged inside the housing is exposed to the outside of the housing and is held by the lens frame A lens barrel characterized in that the position of the lens group in the direction perpendicular to the optical axis can be adjusted.

  2. 2. The lens barrel according to 1, wherein the casing is divided into at least two of an object side and an image plane side of the optical axis of the imaging optical system.

  3. 3. The lens barrel according to claim 1, wherein the lens group held by the lens frame exposed to the outside of the casing is a lens group positioned on a coupling portion side of the casing.

  4). The lens barrel according to any one of claims 1 to 3, wherein the imaging optical system is a variable magnification optical system, and the lens group held by the lens frame is a lens group that does not move in the optical axis direction.

  5. The lens barrel according to any one of claims 1 to 4, wherein after the adjustment of the position of the lens frame in the direction perpendicular to the optical axis, the lens frame is fixed to the housing.

  6). The lens barrel according to any one of claims 1 to 5, wherein the imaging optical system is a bending optical system in which a reflecting surface is disposed in the optical system.

  An imaging apparatus comprising the lens barrel according to any one of 7.1 to 6.

  According to the present invention, it is possible to obtain a lens barrel having a good imaging performance with small variation in imaging performance, and by providing the lens barrel, an image can be taken with a good image quality. An apparatus 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 illustrating an example of an internal arrangement of main constituent units of a camera 100 that is an example of an imaging apparatus including a lens barrel according to the present embodiment. 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 70 containing a foldable imaging optical system capable of zooming is arranged vertically on the right side as shown in the figure, and an opening 81 is formed so as to take in a subject light beam. . The opening 81 is provided with a lens barrier (not shown) that is open to expose the opening 81 and closed to cover the opening 81.

  A flash light emission window 82 has a flash unit 83 formed of a reflector, a xenon tube, other main capacitors, a circuit board, and the like behind the flash light emission window 82. Reference numeral 84 denotes a card-type image recording memory. A battery 85 supplies power to each part of the camera. The image recording memory 84 and the battery 85 can be inserted and removed from a lid (not shown).

  A release button 86 is arranged on the upper surface of the camera 100. When the first step is pushed, a camera shooting preparation operation, that is, a focusing operation and a photometry operation are performed, and when the second step is pushed, a shooting exposure operation is performed. Is called. A main switch 87 is a switch for switching the camera between an operating state and a non-operating state. When switched to the operating state by the main switch 87, the lens barrier (not shown) is opened and the operation of each part is started. When the main switch 87 is switched to the non-operating state, the lens barrier (not shown) is closed and the operation of each unit is ended.

  On the back side of the camera, an image display unit 88 that is composed of an LCD or an organic EL and displays images and other character information is arranged. 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 88, 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. Similarly, although not shown, an external input / output terminal, a strap attaching portion, a tripod seat, and the like are provided.

  FIG. 2 is a schematic cross-sectional view showing the imaging optical system housed in the lens barrel 70 according to the present embodiment. FIG. 4A is a schematic longitudinal sectional view of the lens barrel 70, and FIG. 2B is a movement diagram for zooming of each lens group constituting the imaging optical system.

  In the figure, reference numeral 1 denotes a first lens group. The lens 11 is arranged with the optical axis OA toward the subject, a prism 12 that is a reflecting member that bends the optical axis OA in a substantially right angle direction, and is bent by the prism 12. The lens 13 and the lens 14 are arranged with the optical axis OB as the optical axis. The first lens group 1 is fixed to the first casing 21 and does not move.

  Reference numeral 2 denotes a second lens group, which is held by a lens frame 32. During zooming, the second lens group moves along the optical axis OB as shown in FIG.

  S is a shutter unit, which has a shutter and a diaphragm (not shown). In this example, a shutter unit having a shutter and a diaphragm will be described. However, either a diaphragm or a shutter may be arranged.

  The first lens group 1, the second lens group 2, and the shutter unit S are held by the first housing 21 and unitized as a first lens barrel unit 71.

  Reference numeral 3 denotes a third lens group, which is held by a lens frame 33. As will be described later, as shown in the drawing, a part of the lens frame 33 is exposed to the outside of the second housing 22 and has play in the direction perpendicular to the optical axis of the lens frame 33. After adjusting the position, the lens frame 33 is fixed to the second housing 22, and the third lens group 3 does not move during zooming.

  Reference numeral 4 denotes a fourth lens group, which is held by the lens frame 34. The fourth lens group 4 moves along the optical axis OB as shown in the figure at the time of zooming.

  Reference numeral 5 denotes a fifth lens group, which is held by a lens frame 35. The fifth lens group 5 moves along the optical axis OB as shown in FIG. The fifth lens group 5 is moved to a position indicated by a broken line after zooming and performs focus adjustment (hereinafter also referred to as focusing).

  Reference numeral 6 denotes a sixth lens group which is fixed to the second housing 22 and does not move during zooming.

  Reference numeral 7 denotes an optical filter, in which an infrared light cut filter and an optical low-pass filter are laminated as necessary, and are fixed to the second housing 22.

  Reference numeral 8 denotes an image sensor, which uses a CCD (Charge Coupled Device) type image sensor, a CMOS (Complementary Metal-Oxide Semiconductor) type image sensor, or the like, and is fixed to the second casing 22.

  The third lens group 3, the fourth lens group 4, the fifth lens group 5, the sixth lens group 6, the optical filter 7, and the image sensor 8 are held by the second housing 22 and are united as a second lens barrel unit 72. It has become.

  The first lens barrel unit 71 and the second lens barrel unit 72 thus divided are combined to form a lens barrel 70.

  FIG. 3 is a perspective view showing a schematic internal structure of the lens barrel 70 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.

  In the figure, the lens frame 32 holding the second lens group 2 is slidable in the direction of the optical axis OB by guide shafts 41 and 42. A female screw portion 32 r integrally formed or incorporated in the lens frame 32 is screwed with a lead screw 43 connected to the step motor 44, and the optical axis of the lens frame 32 is rotated by the rotation of the lead screw 43. Driving in the OB direction is performed. Further, the lens frame 32 is formed with a shielding part that is inserted and removed between the light projecting and receiving parts of the photo interrupter 45 that is a photosensor, and the photo interrupter 45 detects the removal or insertion of the shielding part as an initial position, By controlling the rotation direction and amount of rotation of the step motor 44 based on this position, the lens frame 32, that is, the second lens group 2 can be moved to a predetermined position.

  Similarly, the lens frame 34 that holds the fourth lens group 4 and the lens frame 35 that holds the fifth lens group 5 are slidable in the direction of the optical axis OB by the guide shafts 51 and 52. A female screw portion 34r integrally formed or incorporated in the lens frame 34 is screwed with a lead screw 54 connected to the step motor 53, and the optical axis OB direction of the lens frame 34 is rotated by the rotation of the lead screw 54. The female screw portion 35r integrally formed or incorporated in the lens frame 35 is screwed with the lead screw 56 connected to the step motor 55, and the lens frame is rotated by the rotation of the lead screw 56. The driving in the direction of the optical axis OB of 35 is performed. The initial positions of the lens frames 34 and 35 are detected by the photo interrupters 46 and 47, respectively.

  FIG. 4 is an external perspective view of the lens barrel 70 according to the present embodiment.

  As shown in the figure, the lens barrel 70 is configured by combining a first lens barrel unit 71 and a second lens barrel unit 72 in which a shutter unit S is held in a first housing 21.

  The first lens barrel unit 71 includes a step motor 44, a photo interrupter 45, and a flexible printed circuit board FPC1 connected to the shutter unit S. The second lens barrel unit 72 includes step motors 53 and 55, and photo interrupters 46 and 47. The flexible printed circuit board FPC2 is connected to (see FIG. 3). The flexible printed circuit board FPC1 is connected to the flexible printed circuit board FPC2 by the connector C, the connection terminal portion T is connected to a control board (not shown), and drive control of the movable portion of the lens barrel 70 is performed.

  As shown in the drawing, a part of the lens frame 33 that holds the third lens group 3 is exposed on the outer surface of the second housing 22 of the second lens barrel unit. As shown in FIG. 2, a part of the lens frame 33 is exposed on the front and back of the lens barrel 70. Using the exposed part of the lens frame 33, the third lens group 3 is displaced in the plane in the direction perpendicular to the optical axis for adjustment.

  Hereinafter, adjustment of the third lens group 3 using a part of the lens frame 33 exposed from the lens barrel 70 will be described.

  FIG. 5 is a diagram illustrating an example of adjustment of the third lens group 3 using a part of the lens frame 33. This figure is an enlarged view of the periphery of the lens frame 33 in the sectional view shown in FIG.

  As shown in the figure, an adjustment jig 61 is inserted into a recess 33v formed in the lens frame 33 that holds the third lens group 3, and the lens frame 33, that is, the third lens group 3 is moved using the jig 61. Adjustment is performed by moving in a plane perpendicular to the optical axis OB.

  More specifically, the flexible printed circuit board FPC2 is connected to the control unit, and the second, fourth, and fifth lens groups are moved and stopped at predetermined positions, and then the image sensor is driven to image a predetermined chart. The image is displayed on the monitor, and the jig 61 is used to move the lens frame 33, that is, the third lens group 3 in a plane orthogonal to the optical axis OB. At this time, the lens frame 33 is fixed at a position where the image quality is in a desired state while viewing the obtained chart image. This fixing is preferably performed by adhesion.

  Thereby, between the 1st, 2nd lens group accommodated in the 1st lens barrel unit 71, and the 4th, 5th, 6th lens group accommodated in the 2nd lens barrel unit 72. Even if a slight misalignment occurs, the optical performance of the entire optical system can be prevented from deteriorating by moving and adjusting the third lens group 3 in a plane orthogonal to the optical axis. This adjustment may be centering with respect to a specific lens group, or may be performed to adjust the imaging balance of the peripheral portion.

  In other words, after the lens units are assembled, when the lens barrel units divided before and after the optical axis are coupled, even if a slight deviation occurs in the optical axes of the respective lens groups, the coupling unit side By configuring the lens group located at the boundary to be adjusted by moving in the plane perpendicular to the optical axis, a lens barrel capable of obtaining an image with good imaging performance can be obtained.

  FIG. 6 is a diagram illustrating another example of the adjustment of the third lens group 3 using a part of the lens frame 33.

  In this example, the convex portion 33t formed on the lens frame 33 holding the third lens group 3 is sandwiched by an adjustment jig 62, and the lens frame 33, that is, the third lens group 3 is in an in-plane perpendicular to the optical axis OB. It is made to adjust by moving.

  As described above, a part of the lens frame holding the lens group located on the coupling part side that is a boundary part of the plurality of cases is exposed to the outside of the case, and the position of the lens frame in the direction perpendicular to the optical axis is determined. By making the lens barrel adjustable, even if the lens barrel is composed of a housing divided into the object side and the image plane side of the optical axis, the housing in a state where the entire optical system is assembled. It is possible to prevent a deterioration in optical performance due to a slight optical axis shift between bodies, and to obtain a lens barrel having a good imaging performance with little variation in individual imaging performance.

  In the above embodiment, the lens barrel that houses the bending optical system has been described as an example. However, the present invention can also be applied to an optical system that forms an image on an image sensor without bending the optical axis.

  In addition, although the example of adjusting the lens group by exposing the lens frame of the lens group located on the coupling part side which is a boundary part of the plurality of cases has been described, the present invention is not limited to this. The lens frame of the lens group disposed at another position may be exposed and adjusted. Furthermore, although the example of the lens barrel configured by the casing that is divided into the object side and the image plane side of the optical axis of the imaging optical system has been described, the present invention is not limited to this, and a box-shaped casing and lid are also included. What was divided | segmented into the shape-like housing | casing, and the housing | casing may not be divided | segmented.

  Although an example of the image pickup apparatus has been described using a camera, the present invention is not limited to this, and it is needless to say that a camera module mounted on a mobile phone, a PDA (Personal Digital Assistant), or the like is also included.

It is a figure which shows an example of the internal arrangement | positioning of the main structural unit of the camera which is an example of the imaging device provided with the lens barrel which concerns on this Embodiment. It is a schematic sectional drawing which shows the imaging optical system accommodated in the lens barrel which concerns on this Embodiment. It is a perspective view which shows the schematic internal structure of the lens barrel which concerns on this Embodiment. 1 is an external perspective view of a lens barrel according to the present embodiment. It is a figure which shows an example of adjustment of the 3rd lens group using a part of mirror frame. It is a figure which shows the other example of adjustment of the 3rd lens group using a part of mirror frame.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st lens group 2 2nd lens group 3 3rd lens group 4 4th lens group 5 5th lens group 6 6th lens group 7 Optical filter 8 Image sensor 21 1st housing | casing 22 2nd housing | casing 32, 33, 34, 35 Mirror frame 45, 46, 47 Photo interrupter 61 Jig 71 First lens barrel unit 72 Second lens barrel unit OA, OB Optical axis FPC1, FPC2 Flexible printed circuit board

Claims (7)

In a lens barrel containing an imaging optical system having a plurality of lens groups,
A part of the lens frame holding the lens group disposed inside the housing is exposed to the outside of the housing, and the position of the lens group held in the lens frame in the direction perpendicular to the optical axis can be adjusted. Lens barrel characterized by. 2. The lens barrel according to claim 1, wherein the casing is divided into at least two of an object side and an image plane side of the optical axis of the imaging optical system. 3. The lens barrel according to claim 1, wherein the lens group held by the lens frame exposed to the outside of the casing is a lens group positioned on a coupling portion side of the casing. The imaging optical system is a variable magnification optical system, and the lens group held by the lens frame is a lens group that does not move in the optical axis direction. Lens barrel. The lens barrel according to any one of claims 1 to 4, wherein the lens frame is fixed to the casing after the position of the lens frame in the direction perpendicular to the optical axis is adjusted. The lens barrel according to claim 1, wherein the imaging optical system is a bending optical system in which a reflecting surface is disposed in the optical system. An imaging apparatus comprising the lens barrel according to claim 1.

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