JP5765956B2 - Lens barrel and imaging device - Google Patents

Description

  The present invention relates to a zoom lens barrel mounted on an imaging apparatus such as a digital camera, and a photographing apparatus including the lens barrel.

  In a zoom lens barrel mounted on an imaging device such as a digital camera, a plurality of lens units that hold the lens are moved in the optical axis direction by the rotation of the cam barrel, and the movement in the rotational direction is restricted by the straight advance barrel. ing.

  By the way, in recent years, the lens barrel tends to increase in size due to an increase in the number of lens units and an increase in the total length of the lens barrel in response to a request for higher photographing magnification. On the other hand, there is also a demand for a thin digital camera, and it is required to shorten the dimension in the optical axis direction when the lens barrel is retracted as much as possible.

  Therefore, for example, the cam magnification is changed by providing cam grooves on the inner peripheral side and outer peripheral side for one cam cylinder, and moving a plurality of lens units that follow each cam groove relatively in the optical axis direction. A lens barrel has been proposed (Patent Document 1). Further, a front lens unit and a rear lens unit are each held in a cam groove formed in a cam member formed in a third cam member. A retractable lens barrel has been proposed (Patent Document 1).

  Furthermore, a method has been proposed in which a follower is provided in front of and behind the optical axis of the lens unit and the movement stroke of the lens unit is secured by transferring the follower on the same cam cylinder by zoom movement (Patent Document 2).

Japanese Patent Laid-Open No. 2006-078537 JP 2007-114531 A

  However, in Patent Document 1, the relative movement interval of each lens unit in the optical axis direction is increased only within a range in which each lens unit follows cam grooves provided on the inner and outer peripheral sides of one cam cylinder. I can't.

  In addition, the relative movement interval of each lens unit in the optical axis direction can be increased only in the range where each lens unit follows the front group cam groove and the rear group cam groove of the cam member.

  In Patent Document 2, the stroke can be ensured only in a range where one of the plurality of followers of the lens holder reaches the cam cylinder.

  Therefore, an object of the present invention is to provide a mechanism that can increase the relative movement interval of each lens unit in the optical axis direction while shortening the dimension in the optical axis direction when the lens barrel is retracted as much as possible. And

In order to achieve the above object, the lens barrel of the present invention is arranged to be movable along the optical axis direction in a state where the rotation is restricted , respectively, a first lens unit holding a first group lens , a second group lens The second lens unit that holds the lens, the third lens unit that holds the third group lens , and the first lens unit disposed on the inner peripheral side are cam-engaged and move in the optical axis direction while rotating. The first cam member that relatively moves the first lens unit in the optical axis direction, the second lens unit is cam-engaged with the outer peripheral portion, and the third lens unit is cam-engaged with the inner peripheral portion. to, the second lens unit by moving in the optical axis direction while rotating, and and a second cam member are relatively moved in the optical axis direction the third lens unit, said first cam member The second group lens held by the second lens unit and the third group lens held by the third lens unit are arranged substantially coaxially with the second cam member on the outer peripheral side of the second cam member, It characterized that you have been disposed on the inner peripheral side of the second cam member.

  According to the present invention, the relative movement interval of each lens unit in the optical axis direction can be increased while shortening the dimension in the optical axis direction when the lens barrel is retracted as much as possible. For this reason, it is possible to realize a high imaging magnification of the lens barrel and a thin imaging device.

It is the external appearance perspective view which looked at the digital camera which is an example of the embodiment of the imaging device of the present invention from the front side. It is the figure which looked at the digital camera shown in FIG. 1 from the back side. It is a block diagram for demonstrating the control system of a digital camera. It is sectional drawing in the state which has a lens-barrel in a tele position.

  Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view of an external appearance of a digital camera as an example of an embodiment of an imaging apparatus according to the present invention, and FIG. 2 is a view of the digital camera shown in FIG.

  As shown in FIGS. 1 and 2, the digital camera 15 according to the present embodiment includes a finder 20, an auxiliary light source 19, a strobe 21, and a lens barrel 30 used when performing photometric distance measurement on the front side. ing. The lens barrel 30 is of a zoom type that moves in the optical axis direction between the photographing position and the retracted position to change the photographing magnification.

  On the top surface of the digital camera 15, a release button 16, a power switch button 18, and a zoom switch 17 are arranged. Further, as shown in FIG. 2, operation button groups 24 to 29, a display 23 such as an LCD, and a viewfinder eyepiece 22 are disposed on the back side of the digital camera 15.

  FIG. 3 is a block diagram for explaining a control system of the digital camera 15. As shown in FIG. 3, a CPU 46, a ROM 45, a RAM 47, a release button 16, operation button groups 24 to 29, and a display 23 are connected to the bus 44. Further, the power switch button 18, zoom switch 17, memory 40, compression / decompression unit 41, memory card drive 42, and drive circuit 43 are connected to the bus 44.

  Connected to the drive circuit 43 are a zoom mechanism 31 for zooming the lens barrel 30, a focus drive mechanism 32 for driving the focus lens 5, a shutter drive mechanism 34 for driving the shutter 33, and an aperture drive mechanism 36 for driving the aperture 35. Is done.

  The drive circuit 43 is connected to the image sensor 11 such as a CCD sensor or a CMOS sensor and the flash 21. Drive of each unit connected to the drive circuit 43 is controlled via the drive circuit 43 based on a signal from the CPU 46.

  The ROM 45 stores various control programs and the like, and the RAM 47 stores data necessary for the various control programs. The analog signal processing unit 37 performs analog processing on the image data output from the image sensor 11 and outputs the analog data to the A / D conversion unit 38.

  The A / D conversion unit 38 converts analog data captured from the image sensor 11 into digital data and outputs the digital data to the digital signal processing unit 39. The digital signal processing unit 39 performs predetermined processing on the digital data converted by the A / D conversion unit 38 and outputs the processed data to the memory 40 as image data.

  The image data stored in the memory 40 is subjected to compression processing such as JPEG or TIFF by the compression / decompression unit 41, and then output to and stored in a memory card attached to the memory card drive 42.

  Further, the image data stored in the memory 40 or the image data stored in the memory card drive 42 can be expanded by the compression / decompression unit 41 and then displayed on the display 23 via the bus 44.

  Next, the lens barrel 30 will be described in detail with reference to FIG. FIG. 4 is a cross-sectional view of the lens barrel 30 in the tele position.

  As shown in FIG. 4, the lens barrel 30 includes a first lens unit that holds a first group lens, a second lens unit 2 that holds a group lens, and a third lens unit 3 that holds a third group lens. Prepare.

  The lens barrel 30 includes a fourth lens unit 4 that holds a fourth group lens, and a fifth lens unit 5 that holds a fifth group lens. The fifth lens unit of the fifth lens unit 5 is a focus lens. It is said that.

  The element holder 12 holds the imaging element 11, and the fixed cam cylinder 10 is disposed on the subject side of the element holder 12.

  A fixed cam groove 10a is formed in the inner peripheral portion of the fixed cam cylinder 10, and a follower pin of the second movable cam cylinder 8 that follows the fixed cam groove 10a is cam-engaged with the fixed cam groove 10a. When the second movable cam cylinder 8 is driven to rotate, the follower pin moves in the optical axis direction while rotating with respect to the fixed cam cylinder 10 following the fixed cam groove 10a.

  A second rectilinear cylinder 9 is disposed on the inner peripheral portion of the second movable cam cylinder 8, and the second rectilinear cylinder 9 is bayonet-coupled so as to be relatively rotatable with respect to the second movable cam cylinder 8, 2 Moves in the optical axis direction together with the moving cam cylinder 8. A key groove is formed on the outer peripheral portion of the second rectilinear cylinder 9 to be coupled to the rectilinear key 10b provided on the inner peripheral portion of the fixed cam cylinder 10, whereby the rotation of the second rectilinear cylinder 9 is restricted. The

  Further, a second cam groove 8a is formed in the inner peripheral portion of the second movable cam cylinder 8, and a follower pin of the first rectilinear cylinder 7 following the second cam groove 8a is formed in the second cam groove 8a. Engage with cam.

  A first moving cam cylinder 6 is arranged on the outer peripheral side of the first rectilinear cylinder 7, and the first moving cam cylinder 6 is bayonet-coupled to the first rectilinear cylinder 7 so as to be rotatable. The first rectilinear cylinder 7 has a key groove that is coupled to a rectilinear key provided in the second rectilinear cylinder 9, whereby the first rectilinear cylinder 7 is moved in the second state in a state where the rotation is restricted. Due to the cam engagement with the cam barrel 8, it is possible to move relative to the second movable cam barrel 8 in the optical axis direction.

  The first moving cam cylinder 6 is key-coupled to the second moving cam cylinder 8, and moves in the optical axis direction together with the first rectilinear cylinder 7 while rotating as the second moving cam cylinder 8 rotates. ing. A cam groove is formed in the inner peripheral portion of the first movable cam cylinder 6, and the follower pin of the first lens unit 1 that follows the cam groove is cam-engaged with the cam groove.

  Accordingly, the first lens unit 1 moves in the optical axis direction by the rotation of the first moving cam cylinder 6. When the first lens unit 1 moves in the optical axis direction, the first lens unit 1 is key-coupled to the first rectilinear cylinder 7 and its rotation is restricted. Here, the first movable cam cylinder 6 corresponds to an example of the first cam member of the present invention.

  An inner cam cylinder 13 is disposed on the inner peripheral side of the second movable cam cylinder 8, and an inner rectilinear cylinder 14 is disposed on the inner peripheral side of the inner cam cylinder 13.

  The inner rectilinear cylinder 14 is bayonet-coupled to the inner cam cylinder 13 so as to be rotatable. A second cam groove 8b is formed in the inner peripheral portion of the second movable cam cylinder 8, and a follower pin of the inner rectilinear cylinder 14 that follows the second cam groove 8b is cammed in the second cam groove 8b. Engage.

  The inner rectilinear cylinder 14 has a key groove that is coupled to a rectilinear key provided in the second rectilinear cylinder 9, whereby the inner rectilinear cylinder 14 is in a state in which rotation is restricted, and the second movable cam cylinder. It becomes possible to move relative to the second moving cam cylinder 8 in the optical axis direction by cam engagement with the cam 8.

  The inner cam cylinder 13 is key-coupled to the second moving cam cylinder 8 and moves in the optical axis direction together with the inner rectilinear cylinder 14 while rotating as the second moving cam cylinder 8 rotates. In addition, a cam groove that the follower pin 2a of the second lens unit 2 follows is formed on the outer peripheral portion of the inner cam tube 13, and the third lens unit 3 and the fourth lens are formed on the inner peripheral portion of the inner cam tube 13. A cam groove that each follower pin of the unit 4 follows is formed.

  Thereby, the second lens unit 2, the third lens unit 3, and the fourth lens unit 4 are moved in the optical axis direction by the rotation of the inner cam cylinder 13. The second lens unit 2, the third lens unit 3, and the fourth lens unit 4 are key-coupled to the inner rectilinear cylinder 14 and are restricted from rotating. Here, the inner cam cylinder 13 corresponds to an example of a second cam member of the present invention.

  As described above, in the present embodiment, the first moving cam cylinder 6 moves in the optical axis direction while rotating with the rotation of the second moving cam cylinder 8, and is cam-engaged with the first moving cam cylinder 6. The first lens unit 1 that moves moves in the optical axis direction. Further, as the second movable cam cylinder 8 rotates, the inner cam cylinder 13 rotates while moving in the optical axis direction, and the second lens unit 2, the third lens unit 3, and the cam engaged with the inner cam cylinder 13, The fourth lens unit 4 moves in the optical axis direction.

  Thereby, the relative movement interval in the optical axis direction between the first lens unit 1 and the second lens unit 2 can be increased while shortening the dimension in the optical axis direction when the lens barrel 30 is retracted as much as possible. . For this reason, it is possible to realize a high photographing magnification of the lens barrel 30 and a thin digital camera 15.

  The configuration of the present invention is not limited to that exemplified in the above embodiment, and the material, shape, dimensions, form, number, arrangement location, and the like can be changed as appropriate without departing from the scope of the present invention. It is.

DESCRIPTION OF SYMBOLS 1 1st lens unit 2 2nd lens unit 3 3rd lens unit 4 4th lens unit 6 1st moving cam cylinder 8 2nd moving cam cylinder 10 Fixed cam cylinder 13 Inner cam cylinder

Claims (2)

Is movably disposed along the optical axis direction while being respectively the rotation restriction, the holding first lens unit that holds the first group lens, the second lens unit holds the second lens group, and a third lens group 3 lens units,
A first cam member that cam-engages the first lens unit disposed on the inner peripheral side and moves the first lens unit relatively in the optical axis direction by moving in the optical axis direction while rotating; ,
The second lens unit is cam-engaged with an outer peripheral portion, the third lens unit is cam-engaged with an inner peripheral portion, and moves in the optical axis direction while rotating, whereby the second lens unit, A second cam member that relatively moves the third lens unit in the optical axis direction ,
The first cam member is disposed substantially coaxially with the second cam member on the outer peripheral side of the second cam member,
Wherein said second lens group to the second lens unit is held, and the third the third group lens in which the lens unit is held by a lens barrel, wherein that you have been disposed on the inner peripheral side of the second cam member . An imaging apparatus including a zoom lens barrel that moves in the optical axis direction between an imaging position and a retracted position to change an imaging magnification,
An imaging apparatus comprising the lens barrel according to claim 1 as the lens barrel.

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