JP2006098464A - Lens barrel and camera equipped with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a lens barrel whose space utilization efficiency in a width direction is raised by restraining the thickness direction of the lens barrel using a reflecting imaging optical system to the minimum. <P>SOLUTION: The lens barrel is constituted so that its cross section in a direction orthogonal to an optical axis is formed to be nearly square between a reflection member and an imaging device, the short side of the square is made of size decided by an external member and the lens frame of a lens group having the maximum diameter out of lens groups arranged between the reflection member and the imaging device, and position sensors for detecting the existence of a pair of guide shafts, a motor and the predetermined lens group are arranged at the corner parts of the square respectively. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a lens barrel of a variable magnification optical system that is configured to bend a subject light substantially at a right angle by a reflecting member and guide the light to an image sensor, and to perform variable magnification by moving a predetermined lens group.

  Conventionally, in a so-called digital camera in which a signal obtained by photoelectrically converting a subject image by an imaging device is converted into a digital signal, subjected to predetermined processing, and electronically recorded on a recording medium, a reflecting member is disposed in the imaging optical system. An imaging optical system is known in which the optical axis is bent in a direction substantially parallel to the front surface of the camera.

  The bending optical system is generally one in which zooming is performed by individually moving a plurality of lens groups arranged after bending, and a lens barrel is moved using a cam cylinder and a lead screw. It is divided roughly into.

As the movement of the lens group, the lead screw is used to move the two lens groups by the two motors, and the movement of the screwing member screwed to the lead screw of one motor is transmitted to the lens group on the finder side. What was comprised is disclosed (for example, refer patent document 1).
JP 2003-222946 A

  A camera using the above-described bending optical system can form the front of the camera flat without the optical system protruding from the front of the camera body and without using a complicated retracting mechanism. However, since the lens barrel does not retract, there is a problem that the lens itself becomes large unless the volume other than the space between the lenses is minimized.

  The lens moving mechanism layout of the photographing optical system disclosed in the above-mentioned Patent Document 1 is that the arrangement of the guide shaft and the motor requires a space in the lateral width direction of the lens barrel and generates a dead space. There is a problem of increasing.

  In view of the above problems, the present invention obtains a lens barrel that minimizes the thickness direction of the lens barrel using the folded imaging optical system and increases the space utilization efficiency in the width direction, and further includes this lens barrel. Therefore, it is an object to obtain a camera that is both thin and compact.

  The above object is achieved by the following configurations.

  1) A plurality of lens groups that guide subject light, a reflecting member that bends the subject light in a substantially right angle direction, and an imaging device that photoelectrically converts subject light guided by the plurality of lens groups and the reflecting member. And a predetermined lens group of the plurality of lens groups is slidably held in the optical axis direction by a pair of guide shafts, and is a screwing member that is screwed to a lead screw connected to a motor. In the lens barrel configured to move in the optical axis direction according to the movement, the lens barrel has a substantially quadrilateral cross section in a direction perpendicular to the optical axis between the reflecting member and the imaging element. The short side of the quadrilateral is a dimension determined by a lens frame and an exterior member of the lens group having the largest diameter among the lens groups disposed between the reflecting member and the imaging element, and a corner portion of the quadrilateral Each of the pair Id shaft, said motor, a lens barrel, wherein a position sensor for detecting the presence of a predetermined lens group is arranged.

  2) The lens barrel according to 1), wherein the plurality of lens groups, the reflecting member, the imaging element, the pair of guide shafts, and the motor are assembled to one of the exterior members.

  3) The lens barrel according to 1) or 2) having a plurality of the motors and arranged at the same corner of the quadrilateral.

  4) The lens barrel according to any one of 1) to 3), wherein the predetermined lens group moving in the optical axis direction is urged in a direction away from each other by the urging member.

  5) The lens barrel according to any one of 1) to 4), wherein a guide shaft support member is provided in the middle of the pair of guide shafts in the axial direction.

  6) A camera comprising the lens barrel according to any one of 1) to 5).

  In the present invention, between the reflecting member and the image sensor, a cross section perpendicular to the optical axis is formed in a substantially quadrilateral shape, and the short side of the quadrilateral is a lens group disposed between the reflecting member and the image sensor. Among them, the dimensions are determined by the lens frame and the exterior member of the lens group with the largest diameter, and a pair of guide shafts, the motor, and a position sensor for detecting the presence of the predetermined lens group are arranged at the corners of the quadrilateral. By using the lens barrel, it is possible to obtain a lens barrel that minimizes the thickness direction of the lens barrel using the folded imaging optical system and increases the space utilization efficiency in the width direction.

  In addition, by assembling a plurality of lens groups, a reflecting member, an image sensor, a pair of guide shafts, and a motor to one of the exterior members, it is possible to arrange each member only by securing one component accuracy of the exterior member. It is possible to obtain a lens barrel that ensures accuracy and does not cause positional errors due to the combination.

  In addition, when a plurality of motors are provided, the lens barrel can be configured without being uneven by arranging the motors so as to be connected to the same corners of the quadrilateral.

  In addition, the predetermined lens group moving in the optical axis direction is urged in a direction away from each other by the urging member, and is stopped by a nut that is screwed around the entire rotation direction against the urging force. By doing so, it is possible to prevent inadvertent misalignment or breakage when an impact is applied in the lead screw axial direction generated by a nut that is partially screwed into a conventional lead screw.

  In addition, by providing a guide shaft support member in the middle of the pair of guide shafts in the axial direction, it is possible to prevent bending when an impact is applied in a direction perpendicular to the guide shaft. Occurrence can be avoided.

  Furthermore, by using a camera including any one of the lens barrels described above, it is possible to obtain a camera having both the above-described effects, which is thin and small.

  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 vertically on the right side as shown in the figure, and an opening 51 takes in a subject light flux. Has been placed. The opening 51 is provided with a lens barrier (not shown) that is in an open state that exposes the opening 51 and a closed state that covers the opening 51.

  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. The image recording memory 54 and the battery 55 can be inserted and removed from a lid (not shown).

  A release button 56 is disposed on the upper surface of the camera. When the first button is pushed, a shooting preparation operation of the camera, that is, a focusing operation and a photometric operation are performed, and a shooting exposure operation is performed by pushing the second button. A main switch 57 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 57, the lens barrier (not shown) is opened and the operation of each part is started. When the main switch 57 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 58, which is composed of 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.

  Further, although not shown in the drawing, each main component unit is connected to each part, and a circuit board on which various electronic components are mounted is arranged to drive and control each main component unit.

  Further, although not shown, an external input / output terminal, a strap attaching portion, a tripod seat and the like are provided.

  FIG. 2 is a cross-sectional view showing a foldable imaging optical system capable of zooming and encapsulated in a lens barrel 50 according to the present invention. This figure shows a state at the time of widening, which is cut along a plane including two optical axes before and after bending.

  As shown in the figure, OA is the optical axis before bending, and OB is the optical axis after bending. The outside of the lens barrel 50 is composed of a main body A10 and a main body B11 which are exterior members.

  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 A10.

  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 incorporated in the third lens group frame 3k. The third lens group 3 is a lens group in which the third lens group frame 3k is fixed by the main body A10 and does not move during zooming.

  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 integrally with the fourth lens group lens frame 4k during zooming and during focus adjustment (hereinafter also referred to as focusing).

  Reference numeral 5 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 body A10. Reference numeral 6 denotes an image sensor, which uses a charge coupled device (CCD) type image sensor, a complementary metal-oxide semiconductor (CMOS) type image sensor, or the like. The image sensor 6 is assembled to the attachment member 8, and the attachment member 8 is assembled to the main body A 10 together with the image sensor 6. A flexible printed circuit board 7 is connected to the image sensor 6 and is connected to other circuits in the camera. Reference numeral 9 denotes a shutter unit, which is fixed to the main body A10 in the same manner as the third lens group frame 3k.

  The second lens group 2 and the fourth lens group 4 are moved by a set amount from the position in the illustrated wide state toward the third lens group 3 for zooming. Further, the fourth lens group 4 is focused by further moving from the position moved by zooming.

  FIG. 3 is a schematic diagram showing a moving mechanism of the second lens group 2 and the fourth lens group 4. This figure shows a state in which the second lens group 2 and the fourth lens group 4 are in the wide position. In the following drawings, in order to avoid duplication of explanation, the same reference numerals are given to the same functional members. In order to make the explanation easy to understand, the position of the motor or the like is moved out of the lens barrel and is schematically illustrated.

  As shown in the figure, the guide shaft 15 is fitted through the sleeve 2s formed integrally with the second lens group frame 2k and the sleeve 4s formed integrally with the fourth lens group frame 4k. Match. Further, the guide shaft 16 engages with a rotation locking portion 2m formed integrally with the second lens group lens barrel 2k and a rotation locking portion 4m formed integrally with the fourth lens group lens frame 4k. Are arranged. Thereby, the second lens group lens frame 2k and the fourth lens group lens frame 4k are slidable along the guide shafts 15 and 16 in the direction of the optical axis OB.

  The sleeve 2s is preferably formed to extend to the side of the prism 12 as shown in FIG. By doing so, the sleeve 2s can secure a sufficient fitting amount while keeping the entire length of the lens barrel as it is, and the second lens group lens frame 2k, that is, the second lens group 2 can be made smoother. It is possible to move to.

  The guide shafts 15 and 16 also fit through the shutter unit 9 and the third lens group frame 3k. By doing in this way, the 2nd lens group 2, the 3rd lens group 3, and the 4th lens group 4 can be positioned by the pair of guide shafts in the direction perpendicular to the optical axis. It is possible to prevent localization in a shifted state with respect to the second lens group 2 and the fourth lens group 4.

  Further, the second lens group frame 2k has a protrusion 2t formed on the sleeve 2s, and the fourth lens group frame 4k has a protrusion 4t formed on the sleeve 4s. The protrusions 2t and 4t are biased. The compression coil spring 18 which is a member is biased in a direction away from each other. Reference numeral 17 denotes a shaft for preventing the compression coil spring 18 from buckling, and is disposed through the protrusions 2t and 4t.

  Reference numeral 20 denotes a first motor, 21 denotes a second motor, both of which are stepping motors. The first motor 20 has a lead screw 20r, and the second motor 21 has a lead screw 21r. A screwing member (also referred to as a nut) 22 that is screwed around the entire circumference in the rotation direction is screwed into the lead screw 20r. The lead screw 21r is screwed with a screwing member (also referred to as a nut) 24 that is screwed around the entire circumference in the rotation direction. The nuts 22 and 24 are engaged with a rotation stopper (not shown) and are configured to be movable in the direction of the optical axis OB by the rotation of the lead screw.

  As shown in the figure, the nut 22 abuts against a protrusion 2t formed integrally with the second lens group frame 2k, and stops the second lens group frame 2k against the urging force of the compression coil spring 18. Thus, the position of the second lens group frame 2k in the optical axis OB direction is determined. Similarly, as shown in the drawing, the nut 24 abuts against a protrusion 4t formed integrally with the fourth lens group lens frame 4k, and resists the urging force of the compression coil spring 18 to cause the fourth lens group lens frame 4k to move. By stopping, the position of the fourth lens group lens frame 4k in the optical axis OB direction is determined.

  As a result, the nut 22 moves in the direction of the optical axis OB by the rotation of the lead screw 20r of the first motor 20, whereby the second lens group frame 2k can be stopped at a desired position in the direction of the optical axis OB. it can. Similarly, when the nut 24 moves in the direction of the optical axis OB by the rotation of the lead screw 21r of the second motor 21, the fourth lens group lens frame 4k can be stopped at a desired position in the direction of the optical axis OB. it can. That is, by controlling the rotation direction and the rotation amount of the first motor 20 and the second motor 21, the second lens group 2 and the fourth lens group 4 are moved independently to perform zooming, and further, the second motor The fourth lens group 4 is moved by 21 to perform focusing.

  In addition, the position of the nut 22 and the position of the nut 24 indicated by broken lines indicate the positions of the respective nuts when in the tele state.

  In this way, the second lens group lens frame 2k and the fourth lens group lens frame 4k are urged away from each other by the urging member, and the second lens group lens frame 2k and the second lens group lens frame 2k and the second lens group frame 2k are urged against the urging force. A four-lens group frame 4k is stopped by a nut that is screwed all around the rotation direction, and the position in the direction of the optical axis OB is determined. Inadvertent misalignment or breakage when an impact is applied in the direction of the generated lead screw can be prevented.

  Further, the guide shafts 15 and 16 are provided with a guide shaft support member 30 at an intermediate portion in the axial direction in addition to fixing by the fixing members at the end portions.

  FIG. 4 is a perspective view of the guide shaft support member 30. The guide shaft support member 30 can be a resin molded part or a pressed part of a plate material. In this example, an example of a pressed part is shown.

  As shown in the figure, the guide shaft support member 30 is formed with a hole 31 and a hole 32 through which the guide shaft 15 and the guide shaft 16 are fitted and penetrated, and the hole 33 is formed in two bent portions that are bent. Is formed. The hole 33 is used to be fixed to the main body A10 (see FIG. 2) with screws.

  In this way, by providing a guide shaft support member at an intermediate portion in the axial direction of the guide shaft and fixing it to the main body, it is possible to prevent bending when an impact is applied in a direction perpendicular to the guide shaft, and parts caused by bending This makes it possible to avoid malfunctions of the respective parts due to the movement of.

  FIG. 5 is a cross-sectional view of the lens barrel according to the present invention, cut along a plane that passes through the second lens group and is orthogonal to the optical axis OB. In the present embodiment, the second lens group 2 is a lens group having the largest diameter among the lens groups disposed between the prism 12 that is a reflecting member and the imaging element 6.

  As shown in the figure, the outer shape of the lens barrel is formed into a substantially quadrangular shape by the main barrel A10 and the main barrel B11, and the dimension W in the short side direction of the quadrilateral is the second lens group frame 2k. Dimension D and the thickness and clearance of the main cylinder A10 and the main cylinder B11. Further, the guide shaft 15 and the guide shaft 16 are arranged at diagonal positions as shown in the figure, and a position sensor 32 for detecting the presence of the first motor 20 and the second lens group 2 is arranged at the other diagonal position. ing. Although the illustrated position sensor 32 is a photo interrupter, a photo reflector may be used. Whether the position sensor 32 is shielded by the shielding portion 2f formed on the second lens group frame 2k between the light projecting and receiving systems of the position sensor 32 or is not in a position where the light projecting and receiving system of the position sensor 32 is shielded. The lens group position is controlled based on the switching position from the shielding state to the non-shielding state.

  The nut 22 is prevented from rotating by an engaging portion 10m formed on the main body A10, and abuts against a protrusion 2t formed integrally with the second lens group lens frame 2k, so that the second lens group lens frame 2k. Is stopped.

  Note that the cross section cut by a plane that passes through the movable fourth lens group frame 4k and is orthogonal to the optical axis OB is also arranged in the same manner as in FIG. That is, in the case where there are a plurality of motors, the lens barrel can be configured without unevenness by arranging the motors so as to be connected to the same corner of the quadrilateral cross section.

  In this way, the lens barrel after bending has dimensions determined by the lens frame and exterior member of the lens group with the largest diameter, and there is a pair of guide shafts, motors, and lens groups in the diagonal position, that is, the corner space. By positioning the position sensor that detects the lens, it is possible to obtain a lens barrel that minimizes the thickness direction of the lens barrel, increases the space utilization efficiency in the width direction, and also minimizes the width direction. By providing this, it becomes possible to obtain a camera that is both thin and compact.

  Although the description has been given by taking the camera in which the lens barrel is arranged in the vertical direction as an example, it goes without saying that the present invention can be applied to a camera in which the lens barrel is arranged in the horizontal direction.

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. 1 is a cross-sectional view showing a foldable imaging optical system capable of zooming and encapsulated in a lens barrel according to the present invention. It is a schematic diagram which shows the moving mechanism of a 2nd lens group and a 4th lens group. It is a perspective view of a guide shaft support member. It is sectional drawing of the lens barrel which concerns on this invention cut | disconnected by the surface which passes 2nd lens group and orthogonal to optical axis OB.

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 Optical filter 6 Imaging element 9 Shutter unit 10 Main trunk A
11 Main trunk B
15 Guide shaft 16 Guide shaft 18 Compression coil spring 20 First motor 20r Lead screw 21 Second motor 21r Lead screw 22 Threaded member (nut)
24 Threaded member (nut)
30 Guide shaft support member 50 Lens barrel 51 Aperture 100 Camera

Claims (6)

A plurality of lens groups for guiding subject light; a reflecting member that bends the subject light in a substantially right angle direction; and an imaging device that photoelectrically converts subject light guided by the plurality of lens groups and the reflecting member. Among the plurality of lens groups, the predetermined lens group is slidably held in the optical axis direction by a pair of guide shafts and moves according to the movement of a screwing member screwed to a lead screw connected to a motor. In a lens barrel configured to move in the direction of the optical axis,
In the lens barrel, a cross section in a direction orthogonal to the optical axis is formed in a substantially quadrilateral shape between the reflecting member and the imaging element.
The short side of the quadrilateral is a dimension determined by the lens frame and the exterior member of the lens group with the largest diameter among the lens group disposed between the reflecting member and the imaging element,
A lens barrel, wherein a position sensor for detecting the presence of the pair of guide shafts, the motor, and a predetermined lens group is disposed at each corner of the quadrilateral. 2. The lens mirror according to claim 1, wherein the plurality of lens groups, the reflecting member, the imaging element, the pair of guide shafts, and the motor are assembled to one of the exterior members. Torso. 3. The lens barrel according to claim 1, wherein a plurality of the motors are provided and arranged at the same corner of the quadrilateral. The lens barrel according to any one of claims 1 to 3, wherein the predetermined lens group moving in the optical axis direction is urged in a direction away from each other by an urging member. The lens barrel according to any one of claims 1 to 4, wherein a guide shaft support member is provided in the middle of the pair of guide shafts in the axial direction. A camera comprising the lens barrel according to claim 1.

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