JP2016085360A - Lens barrel and imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens barrel which can be easily assembled and also can have lenses smoothly driven with a small rattle.SOLUTION: A lens barrel (6) has a fixed cylinder (4), a cam cylinder (3) rotating in a peripheral direction relative to the fixed cylinder (4), a cam groove (3a) formed on the cam cylinder (4), first follower means (4a) provided to the fixed cylinder (4) to follow up the cam groove (3a), and displaceable with elastic force, fixed second follower means (4c), and introduction means (3b) formed on the cam cylinder (4) and introducing the second follower means (4c) when the fixed cylinder (3) is incorporated in the cam cylinder (4).SELECTED DRAWING: Figure 5

Description

  The present invention relates to a lens barrel of an imaging apparatus such as a digital camera.

  The imaging apparatus can perform zooming by moving the lens unit of the lens barrel in the optical axis direction using a zoom mechanism. For example, a cam cylinder provided with a cam groove is disposed on the outer periphery of a fixed cylinder provided with a straight advance groove, and the lens group is caused to follow the cam groove while being guided linearly in the straight advance groove. Accordingly, zooming can be performed by rotating the cam cylinder and moving the lens unit in the optical axis direction. However, although the cam cylinder rotates around the fixed cylinder, the dimensional variation of the cam cylinder occurs, and rattling occurs. This play may cause the lens position to shift and affect the performance.

  Patent Document 1 discloses a configuration in which a backlash of each other is removed by incorporating a tapered follower into the lens group with respect to the cam cylinder, the lens group, and the configuration. Patent Document 2 discloses a configuration that removes play by pressing a ball against a cam groove of a cam cylinder.

JP 2009-294267 A JP 2009-80437 A

  However, in the configuration of Patent Document 1, a separate follower is inserted and fixed from the outside. For this reason, the number of parts increases and the work becomes complicated. In the configuration of Patent Document 2, it is necessary to incorporate a ball, and a spring for pressing the ball is required, which increases the number of parts and makes assembly work difficult.

  On the other hand, it is conceivable to remove the play between the cam cylinder and the fixed cylinder by using a follower means having an elastic force, but it may not always be preferable in terms of assemblability.

  Therefore, the present invention provides a lens barrel and an imaging apparatus that can be assembled easily and can be smoothly driven with little play.

  A lens barrel according to one aspect of the present invention includes a fixed tube, a cam tube that rotates in a circumferential direction with respect to the fixed tube, a cam groove formed in the cam tube, and a cam groove that follows the cam tube. A first follower means that is displaceable by elastic force and a fixed second follower means provided on the fixed cylinder, and formed on the cam cylinder, and the first cylinder means when the fixed cylinder is incorporated into the cam cylinder. Introducing means for introducing a second follower means.

  An imaging apparatus according to another aspect of the present invention includes the lens barrel and an imaging element that photoelectrically converts an optical image formed via a lens unit of the lens barrel.

  Other objects and features of the invention are described in the following embodiments.

  According to the present invention, it is possible to provide a lens barrel and an image pickup apparatus that can be easily assembled and can smoothly drive a lens with little play.

It is a perspective view of the cam cylinder and fixed cylinder of the lens barrel in the present embodiment. It is sectional drawing of the accommodation state (at the time of power supply OFF) of the lens-barrel in this embodiment. It is sectional drawing of the operation state (at the time of power supply ON) of the lens-barrel in this embodiment. It is a perspective view of the fixed cylinder of the lens barrel in this embodiment. It is sectional drawing of the cam cylinder of the lens barrel in this embodiment. It is a block diagram of the cam cylinder and fixed cylinder of the lens barrel in this embodiment. It is an external appearance perspective view of an imaging device provided with the lens barrel in this embodiment. It is a rear view of the imaging device in this embodiment. It is a block diagram of the imaging device in this embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  First, with reference to FIG. 6A, FIG. 6B, and FIG. 7, the imaging apparatus provided with the lens barrel in the present embodiment will be described. FIG. 6A is an external perspective view (front perspective view) of the imaging apparatus (digital camera 23). FIG. 6B is a rear view of the imaging apparatus. FIG. 7 is a block diagram of the imaging apparatus. The digital camera 23 of the present embodiment includes a zoom mechanism that moves the lens unit in the optical axis direction between the shooting position and the storage position to change the shooting magnification.

  As shown in FIG. 6a, on the front side of the digital camera 23, a finder 21 for determining the composition of the subject, an auxiliary light source 20, a strobe 22, and a lens mirror used for photometry and distance measurement (focus detection) A cylinder 6 (lens barrel) is disposed. On the top surface of the digital camera 23, a release button 17, a zoom switch 18, and a power switch button 19 are arranged. As shown in FIG. 6 b, operation buttons 26 to 31, a display 25 (liquid crystal unit) such as an LCD, and a viewfinder eyepiece unit 24 are arranged on the back of the digital camera 23.

  The display 25 is an image display means for displaying the image data stored in the memory 38 and the image data read from the memory card on the screen. The control unit (control system) includes a CPU 44, a ROM 43, and a RAM 45. The control unit is connected to various components such as the release button 17, the operation buttons 26 to 31, the display 25, the memory 38, and the memory card drive 40 via the bus 42.

  The drive circuit 41 is connected to the control unit via the bus 42. The drive circuit 41 is connected to the zoom mechanism 32, the focus drive mechanism 16, the shutter drive mechanism 33, the aperture drive mechanism 34, the image sensor 15 such as a CCD or CMOS, and each part of the strobe 22. Each part is a control unit. It is controlled based on the signal from The zoom mechanism 32 drives the lens barrel 6 (lens barrel portion) via a motor. The focus drive mechanism 16 drives the focus lens 12 via a motor. The shutter drive mechanism 33 drives the shutter 7a. The aperture drive mechanism 34 drives the aperture 7b. The image sensor 15 photoelectrically converts an optical image (subject image) formed via the lens unit of the lens barrel 6 and outputs an image signal. With such a configuration, the drive circuit 41 controls driving of each unit based on a signal from the control unit (CPU 44).

  The ROM 43 stores various control programs for controlling the functions of the above-described units. The RAM 45 stores data necessary for various control programs. The analog signal processing unit 35 performs analog processing on the image data output from the image sensor 15 and outputs the analog data to the A / D conversion unit 36. The A / D conversion unit 36 converts analog data obtained from the image sensor 15 into digital data and outputs the digital data to the digital signal processing unit 37. The digital signal processing unit 37 performs a predetermined process on the digital data converted by the A / D conversion unit 36 and outputs it to the memory 38 as image data. The image data is stored in the memory 38.

  The image data stored in the memory 38 is subjected to compression processing such as JPEG or TIFF by the compression / decompression unit 39 according to the operation of the operation button 27. After the compression processing by the compression / decompression unit 39, the image data is output to and stored in a memory card attached to the memory card drive 40. The compression / decompression unit 39 performs decompression processing of image data stored in the memory 38 or image data stored in the memory card. The image data after the expansion process can be displayed on the display 25 (display unit) via the bus 42. When the user views the image displayed on the display 25 and determines that the image is unnecessary, the user can delete the image by operating the operation button 28.

  Next, the configuration of the lens barrel 6 provided in the digital camera 23 will be described with reference to FIGS. FIG. 1 is a perspective view of the cam barrel 3 and the fixed barrel 4 of the lens barrel 6 in the present embodiment. FIG. 2A is a cross-sectional view of the lens barrel 6 in a stored state (when the power is off). FIG. 2B is a cross-sectional view of the lens barrel 6 in the manipulated state (when the power is turned on). FIG. 3 is a perspective view of the fixed cylinder 4. FIG. 4 is a cross-sectional view of the cam cylinder 3. 4A is a diagram viewed from the direction orthogonal to the optical axis, FIG. 4B is a diagram viewed from the optical axis direction, and FIG. 4A is a view taken along line BB in FIG. 4B. It corresponds to a cross section.

  2A and 2B, the lens barrel 6 includes a first lens unit 5, a second lens unit 1, a third lens unit 8, a fourth lens unit 10, and a focus lens 12 (focus lens unit). ). The first lens unit 5 is held by first lens holding means 61. Behind the first lens holding means 61 (image side), the second lens holding means 2 for holding the second lens unit 1 is disposed. Behind the second lens holding means 2 (image side), an aperture / shutter means 7 in which a shutter 7a (shutter unit) and an aperture 7b (aperture unit) are integrally formed is disposed. A third lens holding means 9 for holding the third lens unit 8 is disposed behind the aperture / shutter means 7 (image side). A fourth lens holding means 11 for holding the fourth lens unit 10 is arranged behind the third lens holding means 9 (image side). A focus lens holding unit 13 that holds the focus lens 12 is disposed behind (on the image side) the fourth lens holding unit 11.

  As shown in FIGS. 1, 2 a, and 2 b, the lens barrel 6 has a fixed barrel 4. A cam cylinder 3 is provided on the outer periphery of the fixed cylinder 4. Further, an image sensor holding unit 14 for holding the image sensor 15 is provided on the most back side (image side). The focus drive mechanism 16 (focus drive means) is fixed in front of the image sensor holding means 14 (object side). The motor which is the focus drive mechanism 16 is provided with a screw, and the focus lens holding means 13 is configured to follow the operation. With such a configuration, the focus lens 12 can move in the front-rear direction (optical axis direction) along the optical axis OA, and the entire imaging apparatus can be focused (focus adjustment is performed).

  A cam groove 3 a is formed on the inner periphery of the cam cylinder 3. The cam groove 3a is configured such that follower means 4a and 4c (fixed cylinder follower means) provided in the fixed cylinder 4 abut. A cam groove 3 c (first lens following cam groove) is formed on the outer periphery of the cam cylinder 3. The first lens holding means 61 is configured to follow the cam groove 3c. A cam groove 3 d (second lens following cam groove) is formed on the inner periphery of the cam cylinder 3. The second lens holding means 2 is configured to follow the cam groove 3d. A plurality of other cam grooves are formed on the inner periphery of the cam cylinder 3. The aperture / shutter unit 7, the third lens holding unit 9, and the fourth lens holding unit 11 are configured to follow each of the plurality of cam grooves.

  The fixed cylinder 4 is provided with a straight travel restricting means 4e. The rectilinear regulation means 4e guides the second lens holding means 2 in a rectilinear direction. A guide bar (not shown) is attached to the fixed cylinder 4, and the diaphragm / shutter means 7, the third lens holding means 9, and the fourth lens holding means 11 are guided in a straight line. Near the tip of the fixed cylinder 4 (near the most object side), a rectilinear regulating means 4d for guiding the first lens holding means 61 rectilinearly is provided. The straight movement restricting means 4d guides the first lens holding means 61 straight by fitting into the first straight movement groove 6a formed on the inner periphery of the first lens holding means 61 and performing restriction.

  In the fixed cylinder 4, two follower means 4a and one follower means 4c are arranged at equal intervals of approximately 120 degrees. The follower means 4a is provided on the elastic means 4b composed of a mold spring. The elastic means 4b is configured to press the follower means 4a in the radial direction (radial direction perpendicular to the optical axis direction) by its elastic force. Thus, in this embodiment, the follower means 4a is an elastic follower means. On the other hand, the follower means 4 c is a fixed follower means fixed on the outer surface of the fixed cylinder 4 (having no elastic force). In the present embodiment, the follower means 4a is configured to be longer in the radial direction than the follower means 4c.

  As shown in FIG. 1, the fixed cylinder 4 is inserted into the cam cylinder 3 from the front (object side) of the cam cylinder 3. At this time, the follower means 4a is retracted to the inside of the fixed cylinder 4 (in the radial direction approaching the optical axis OA) by the elastic force, and the cam cylinder 3 and the fixed cylinder 4 are assembled. In the present embodiment, as shown in FIG. 4, the cam cylinder 3 is provided with a built-in introduction portion 3 b (introduction means such as an introduction slit) on the upper surface (near the cam groove 3 a). When the cam cylinder 3 and the fixed cylinder 4 are assembled, the follower means 4c is configured to pass through the built-in introduction portion 3b. On the other hand, such a built-in introduction part (introduction means) is not provided for the follower means 4a.

  In the present embodiment, the length of the follower means 4c (the length in the radial direction that is the direction orthogonal to the optical axis) is shorter than the length of the follower means 4a. Further, the bottom surface position of the assembly introducing portion 3b is configured to be higher than the bottom surface position of the cam groove 3a (the bottom surface position of the assembly introducing portion 3b is the center of the cam cylinder 3 than the bottom surface position of the cam groove 3a). (Close to the optical axis OA). In other words, the depth in the radial direction of the assembly introducing portion 3b is shallower than the depth of the cam groove 3a. For this reason, the follower means 4c that is short in the radial direction can pass through the assembly introduction part 3b, but the follower means 4a that is long in the radial direction cannot pass through the assembly introduction part 3b. Moreover, since the assembly introduction part 3b is shallow, a part of the tip of the cam groove 3a is continuously connected to the incorporation introduction part 3b.

  In the present embodiment, two follower means 4a are provided as elastic follower means, and one follower means 4c is provided as a fixed follower means. However, the number of elastic follower means or fixed follower means is not limited to this, and it is sufficient that at least one elastic follower means and at least one fixed follower means are provided. When a plurality of fixed follower means are provided, the number of built-in introducing portions 3b can be increased according to the number of the fixed follower means. In this embodiment, by providing one fixed follower means, it is possible to obtain a reference in the direction in which the load of the other two elastic follower means is applied, and the eccentricity of the central axes of the cam cylinder 3 and the fixed cylinder 4 can be obtained. Can be reduced.

  Next, with reference to FIG. 5, the state where the fixed cylinder 4 is incorporated in the cam cylinder 3 and the follower means 4a and 4c are inserted into the cam groove 3a will be described. FIG. 5 is a configuration diagram of the cam cylinder 3 and the fixed cylinder 4. 5A is a diagram viewed from the optical axis direction, FIG. 5B is a diagram viewed from the direction orthogonal to the optical axis, and FIG. 5A is a line AA in FIG. 5B. It corresponds to a cross section. In FIG. 5A, A1 is an enlarged sectional view of line A1-A1, A2 is an enlarged sectional view of line A2-A2, and A3 is an enlarged view of region A3.

  After the fixed cylinder 4 is assembled into the cam cylinder 3, that is, after the follower means 4c is inserted into the cam groove 3a, the cam cylinder 3 is rotatable in the circumferential direction around the optical axis OA with respect to the fixed cylinder 4 (lens Can be driven). In this embodiment, the cam cylinder 3 is rotatable within a predetermined range indicated by an arrow in FIG. 5A, and the follower means 4c (fixed follower means) does not pass through the built-in introducing portion 3b. It is configured.

  On the other hand, the follower means 4a (elastic follower means) can pass through the built-in introduction portion 3b. However, in the present embodiment, as described above, the bottom surface of the built-in introduction portion 3b is shallower than the bottom surface (back end) of the cam groove 3a. For this reason, although the cam groove 3a and the built-in introduction part 3b are connected to each other, the tip of the follower means 4a is not affected by the built-in introduction part 3b (without being detached from the cam groove 3a). It can continue to fit into the groove 3a. As described above, according to the present embodiment, there is no influence by providing the built-in introducing portion 3b connected to the cam groove 3a, and it is possible to smoothly perform lens driving such as zoom operation while avoiding deterioration in accuracy and play. It can be carried out.

  The cam groove 3 a formed on the inner circumference of the cam cylinder 3 is provided over the entire circumference in the circumferential direction of the cam cylinder 3. By incorporating the follower means 4a, 4c into the cam groove 3a, the cam cylinder 3 can be rotated 360 degrees (rotation around the entire circumference). However, in the present embodiment, it is necessary to configure the follower means 4c so as not to pass through the built-in introduction portion 3b during use (when driving the lens).

  As described above, the lens barrel 6 of the present embodiment includes the fixed barrel 4 and the cam barrel 3 that rotates in the circumferential direction (rotation direction around the optical axis OA) with respect to the fixed barrel 4. The lens barrel 6 includes a cam groove 3a formed in the cam cylinder 3 and follower means 4a and 4c provided in the fixed cylinder 4 so as to follow the cam groove 3a. The follower means 4a is a first follower means that can be displaced (elastically deformed) by an elastic force, and the follower means 4c is a second follower means that is fixed (not displaceable by an elastic force). The lens barrel 6 is formed on the cam barrel 3 and has introduction means (incorporation introduction portion 3b) for introducing the second follower means when the fixed barrel 4 is incorporated into the cam barrel 3.

  Preferably, the introducing means is connected to the cam groove 3a. Further preferably, the length of the second follower means in the radial direction (direction orthogonal to the circumferential direction) of the fixed cylinder 4 is shorter than the length of the first follower means, and the bottom surface position of the introduction means in the radial direction is the cam groove. It is shallower than the bottom surface position of 3a. That is, the bottom surface position of the introducing means is closer to the optical axis OA (the rotation center of the cam tube 3) than the bottom surface position of the cam groove 3a.

  Preferably, the fixed cylinder 4 includes elastic means 4b that applies an elastic force in a direction orthogonal to the circumferential direction (the radial direction of the fixed cylinder 4) when the cam cylinder 3 rotates in the circumferential direction. The first follower means is provided on the elastic means 4b. Preferably, two follower means 4a as the first follower means and one follower means 4c as the second follower means are provided at equal intervals (approximately 120 degree intervals) in the circumferential direction of the fixed cylinder 4. Preferably, the cam groove 3a is formed on the entire circumference of the cam cylinder 3 in the circumferential direction. Preferably, when the fixed cylinder 4 is incorporated in the cam cylinder 3, the first follower means is retracted in the direction perpendicular to the circumferential direction by utilizing the elastic force of the first follower means, and the first follower means is moved into the cam groove. 3a can be inserted.

  Preferably, the second follower means is configured not to pass through the introducing means when the cam cylinder 3 rotates in the circumferential direction (when driving the lens). More preferably, the cam cylinder 3 is rotatable in the circumferential direction within a predetermined range in which the second follower means does not pass through the introducing means. Preferably, when the first follower means passes through the introducing means when the cam cylinder 3 rotates in the circumferential direction, the first follower means is in a state of being fitted in the cam groove 3a without being affected by the introducing means. maintain.

  Preferably, the lens barrel 6 includes a lens unit (first lens unit 5 or second lens unit 1) and holding means (first lens holding means 61 or second lens holding means 2) for holding the lens unit. Have. The fixed cylinder 4 is formed with rectilinear restricting means 4d (or rectilinear restricting means 4e) for guiding the holding means rectilinearly.

  As described above, the lens barrel of the present embodiment can be connected by removing the backlash and removing the backlash between the fixed barrel and the cam barrel, and there is no problem in assembling and operability of the lens barrel. . For this reason, according to the present embodiment, it is possible to provide a lens barrel and an imaging apparatus that can be easily assembled and can be smoothly driven with little play.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

  The digital camera 23 of the present embodiment is an image pickup apparatus in which the lens barrel 6 and the image pickup apparatus main body having the image pickup element 15 are integrally configured, but the present invention is not limited to this. The present embodiment is also applicable to a lens device (lens barrel 6) that can be attached to and detached from the imaging apparatus main body.

3 Cam cylinder 3a Cam groove 3b Built-in introduction part (introduction means)
4 fixed cylinder 4a follower means (first follower means)
4c Follower means (second follower means)
6 Lens barrel

Claims (12)

A fixed cylinder;
A cam cylinder that rotates in a circumferential direction with respect to the fixed cylinder;
A cam groove formed in the cam cylinder;
A first follower means that is provided on the fixed cylinder so as to follow the cam groove and can be displaced by an elastic force; and a fixed second follower means;
A lens barrel, comprising: an introduction means formed on the cam cylinder and for introducing the second follower means when the fixed cylinder is incorporated into the cam cylinder.   The lens barrel according to claim 1, wherein the introduction unit is connected to the cam groove. The length of the second follower means in the radial direction of the fixed cylinder is shorter than the length of the first follower means,
The lens barrel according to claim 1 or 2, wherein a bottom surface position of the introduction means in the radial direction is shallower than a bottom surface position of the cam groove. The fixed cylinder has elastic means for applying the elastic force in a direction orthogonal to the circumferential direction when the cam cylinder rotates in the circumferential direction;
The lens barrel according to any one of claims 1 to 3, wherein the first follower means is provided on the elastic means.   5. The two follower means as the first follower means and the one follower means as the second follower means are provided at equal intervals in the circumferential direction of the fixed cylinder. The lens barrel according to any one of the above.   The lens barrel according to claim 1, wherein the cam groove is formed on the entire circumference of the cam barrel in the circumferential direction.   When assembling the fixed cylinder into the cam cylinder, the first follower means is retracted in a direction perpendicular to the circumferential direction by utilizing the elastic force of the first follower means, and the first follower means is moved to the cam The lens barrel according to claim 1, wherein the lens barrel can be inserted into the groove.   The said 2nd follower means is comprised so that it may not pass the said introduction means, when the said cam cylinder rotates in the said circumferential direction, The one of Claims 1 thru | or 7 characterized by the above-mentioned. Lens barrel.   9. The lens barrel according to claim 8, wherein the cam barrel is rotatable in the circumferential direction within a predetermined range in which the second follower means does not pass through the introduction means.   When the first follower means passes through the introduction means when the cam cylinder rotates in the circumferential direction, the first follower means is fitted in the cam groove without being affected by the introduction means. 10. The lens barrel according to claim 1, wherein the lens barrel is configured to maintain the above. A lens unit;
Holding means for holding the lens unit;
The lens barrel according to any one of claims 1 to 10, wherein the fixed barrel is formed with a rectilinear regulating means for guiding the holding means so as to rectilinearly. The lens barrel according to any one of claims 1 to 11,
An imaging device comprising: an imaging device that photoelectrically converts an optical image formed through a lens unit of the lens barrel.