JP5361566B2 - Lens barrel and imaging device - Google Patents

Description

  The present invention relates to a lens barrel and an imaging apparatus that move a lens holding frame on which a lens is mounted in an optical axis direction.

  In recent years, an imaging apparatus such as a digital camera has been required to be small and thin at the same time as the magnification is increased. In order to achieve high magnification, the driving amount of the lens barrel must be increased. For this reason, a method of elongating the cam groove for driving the lens holding frame or increasing the number of steps of the lens barrel is used, but this increases the size of the lens barrel in the optical axis direction and radial direction, respectively.

  On the other hand, there is known a lens barrel having a configuration that reduces the dimension in the optical axis direction and suppresses the increase in the radial dimension while maintaining a high magnification (see Patent Document 1).

JP-A-2005-091782

  However, the conventional lens barrel has the following problems. That is, in the configuration of the lens barrel described in Patent Document 1, since the focus motor is disposed inside the lens barrel, there is a limit to the reduction in the dimension in the radial direction. Furthermore, the dimension in the optical axis direction is also restricted by the lead screw of the focus motor.

  In contrast, placing the focus motor outside the lens barrel is effective in reducing the radial dimension, but when the focus motor is driven by gear connection from the focus motor, the lead screw is placed inside the lens barrel. Will be placed. Therefore, there is still a limit to the reduction of the dimension in the optical axis direction.

  In addition, when the focus motor is provided with a lead screw and is directly screwed to the lens holding frame to drive the focus, the lead screw is not limited by the size in the optical axis direction, but only by the focus drive amount. The lens barrel will be cut out. Accordingly, the rigidity of the lens barrel is lowered, and the lens barrel driving becomes unstable.

  Therefore, the present invention provides a lens barrel and a lens barrel that can achieve small size and thinness and achieve stable lens barrel driving with high magnification even when the focus driving unit is disposed outside the lens barrel. An object is to provide an imaging device.

To achieve the above object, a lens barrel according to claim 1, wherein the A lens barrel is moved in the optical axis direction of the first lens holding frame in which the first lens is attached, a first on the outer periphery A drive pin and a second drive pin are provided, a cam cylinder that moves the first lens holding frame in the optical axis direction, and a fixing that is engaged with the outside of the cam cylinder and holds the cam cylinder rotatably. A first straight groove and a second straight groove that are rotatably engaged with the outer side of the tube and the first drive pin and the second drive pin, respectively, in the optical axis direction. A rotating cylinder formed on the periphery and provided with a first gear portion on the outer periphery, and disposed on the outer side of the rotating cylinder, meshes with the first gear portion to transmit the power of the first driving unit. a second gear portion that rotates the rotary cylinder, the second lens is mounted, the optical axis A second lens holding frame having an arm portion extending in a direction perpendicular, is disposed outside of the rotating cylinder, through the arm portion and the second moving said second lens holding frame in the optical axis direction and a drive section, in the rotation direction about the optical axis, the first driving pin and one of the second drive pin, the first drive pin of the first straight groove engaged with the There is a phase in which the second drive pin does not engage with the second rectilinear groove, and when viewed from the front in the optical axis direction of the lens barrel , the first drive pin has the second phase in the phase . wherein the position near Rukoto facing the gear unit.

  According to the lens barrel of the first aspect of the present invention, even if the focus drive unit is disposed outside the lens barrel, the lens barrel achieves a small size and a thin shape while maintaining a high magnification, and can stably drive the lens barrel. Can be achieved.

It is a perspective view which shows the external appearance of a compact digital still camera. 1 is a perspective view showing an external appearance of a lens barrel 1. 1 is an exploded perspective view showing a configuration of a lens barrel 1. FIG. 2 is a front view showing the structure of the lens barrel 1 excluding the lens holding frames 11 and 17. FIG. It is a figure which shows the structure of the lens-barrel 1 seen from the arrow A direction of FIG. It is a figure which shows the structure of the lens-barrel 1 seen from the arrow B direction of FIG. It is sectional drawing which shows the structure of the lens-barrel 1 seen from the arrow CC line direction of FIG. FIG. 5 is a cross-sectional view showing the structure of the lens barrel 1 viewed from the direction of the arrow DD in FIG. 4. FIG. 4 is a development view showing the shape of the side surfaces of the cam cylinder 12 and the rotary cylinder 14.

  Embodiments of a lens barrel and an imaging apparatus of the present invention will be described with reference to the drawings. The imaging apparatus of this embodiment is applied to a compact digital still camera equipped with a lens barrel.

  FIG. 1 is a perspective view showing an appearance of a compact digital still camera. The compact digital still camera 100 includes a camera main body 110 and a display unit 120 that are divided in the thickness direction. The camera body 110 is provided with a lens barrel 1. The camera main body 110 is also provided with a main switch 111, a photographing switch 112, a zoom lever 113, an optical viewfinder objective window 114, a photometric light receiving window 115, and a flash light emitting section 116.

  The main switch 111 is a switch for switching on and off of the power. The photographing switch 112 is a switch that performs photographing preparation operations such as photometry and distance measurement (AF) by a half-press operation, and captures and records an image by a full-press operation. The zoom lever 113 causes the lens barrel 1 to perform a zoom operation by performing a rotation operation.

  Although not shown, the camera body 110 is equipped with an image sensor such as a CCD sensor or a CMOS sensor that photoelectrically converts a subject image obtained by the photographing optical system of the lens barrel 1.

  Next, the scaling operation will be described. FIG. 2 is a perspective view showing the appearance of the lens barrel 1. FIG. 3 is an exploded perspective view showing the configuration of the lens barrel 1. The lens barrel 1 includes lens holding frames 11 and 17, a rectilinear cylinder 18, a cam cylinder 12, a fixed cylinder 13, a rotating cylinder 14, and a focus lens holding frame 19 in the optical axis direction. Further, the lens barrel 1 includes a focus motor 15, a CCD holder 16, a rectilinear guide shaft 20 (see FIG. 5), a biasing spring 21 (see FIG. 5), a zoom motor 22 and gears 23, 24, 25, and 26 (see FIG. 5). 4).

  A cam follower 12c and three drive pins 12d, 12e, 12f (see FIG. 4) project from the outer periphery of the cam cylinder 12. The cam follower 12 c engages with a cam groove 13 a formed on the inner peripheral surface of the fixed cylinder 13 disposed outside the cam cylinder 12. The drive pins 12 d, 12 e, and 12 f also pass through a groove hole 13 b provided in the fixed cylinder 13 and engage with the rectilinear groove 14 a of the rotating cylinder 14 disposed outside the fixed cylinder 13.

  Here, the fixed cylinder 13 is fixed to the CCD holder 16. The rotating cylinder 14 is held so as to be rotatable relative to the fixed cylinder 13, and the movement of the rotating cylinder 14 in the optical axis direction is restricted by a cover member (not shown). That is, the rotating cylinder 14 is rotatably engaged with the outside of the fixed cylinder 13. In addition, three rectilinear grooves 14a that are respectively engaged with the three drive pins 12d, 12e, and 12f are formed in the optical axis direction on the inner periphery of the rotating cylinder 14, and the outer periphery of the rotating cylinder 14 includes a gear. A portion 14d is provided.

  Further, a zoom motor 22 (drive source) is fixed to the CCD holder 16, and the rotating cylinder 14 is rotated via gears 23, 24, 25, and 26. That is, the gears 23, 24, 25, and 26 transmit the power of the zoom motor 22 to a gear portion 14 d (first gear portion) provided on the outer periphery of the rotary cylinder 14. When the rotating cylinder 14 is rotated, the cam cylinder 12 rotates integrally with the rotating cylinder 14 by the engagement of the drive pins 12d, 12e, 12f and the rectilinear groove 14a, and the cam follower 12c and the cam groove 13a It moves in the optical axis direction by engagement.

  A cam follower 11a protrudes from the lens holding frame 11 on which the lens is mounted. Further, a cam follower 17 a is projected from the lens holding frame 17. The cam followers 11 a and 17 a respectively penetrate the rectilinear groove holes 18 a and 18 b of the rectilinear cylinder 18 and engage with cam grooves 12 a and 12 b formed on the inner peripheral surface of the cam cylinder 12, respectively.

  The cam cylinder 12 and the rectilinear cylinder 18 are connected by a bayonet mechanism, move together in the optical axis direction, and are held so as to be relatively rotatable about the optical axis m.

  Since the rotation of the lens holding frames 11 and 17 is restricted by the rectilinear groove holes 18a and 18b, when the cam cylinder 12 rotates, the cam followers 11a and 17a move along the cam grooves 12a and 12b. 11 and 17 also move in the optical axis direction without rotating. By changing the distance between the lens holding frames 11 and 17 in this way, a zooming operation is performed.

  Next, the focus operation will be described. FIG. 4 is a front view showing the structure of the lens barrel 1 excluding the lens holding frames 11 and 17. FIG. 5 is a diagram showing the structure of the lens barrel 1 viewed from the direction of arrow A in FIG. 6 is a view showing the structure of the lens barrel 1 viewed from the direction of arrow B in FIG. FIG. 7 is a cross-sectional view showing the structure of the lens barrel 1 viewed from the direction of the arrow CC in FIG. FIG. 8 is a cross-sectional view showing the structure of the lens barrel 1 viewed from the direction of arrow DD in FIG. FIG. 9 is a development view showing the shapes of the side surfaces of the cam cylinder 12 and the rotary cylinder 14.

  As shown in FIG. 8, the focus lens holding frame 19 has an arm portion 19 a that holds the focus lens 19 b and extends toward the outside of the rotating cylinder 14 that is in a direction orthogonal to the optical axis m. A nut member (not shown) with which the arm portion 19a abuts is screwed with a lead screw 15a (see FIG. 7) provided on the focus motor 15. The nut member, the lead screw 15a, and the focus motor 15 are examples of a focus drive unit.

  Further, the focus lens holding frame 19 is always urged in a direction (upper side in FIG. 5) in contact with the nut member by a one-sided spring 21 provided between the focus lens holding frame 19 and further extended in the optical axis direction. The linear guide shaft 20 is engaged. Thereby, the focus lens holding frame 19 moves in the direction of the optical axis integrally with a nut member (not shown) driven by the lead screw 15a of the focus motor 15, and performs a focus operation.

  Here, since the focus motor 15 is disposed outside the rotary cylinder 14 and is fixed to the CCD holder 16, the size of the lens barrel in the radial direction can be reduced. Furthermore, the dimension in the optical axis direction, which is restricted by the lead screw of the focus motor, can be reduced. As a result, the lens barrel can be reduced in size and thickness.

  However, since the focus lens holding frame 19 is in contact with a nut member (not shown) screwed with the lead screw 15a of the focus motor 15 disposed outside the rotary cylinder 14, the following There was a problem. That is, in the drive range of the focus lens holding frame 19, the arm portion 19a interferes with the fixed cylinder 13 and the rotary cylinder 14 that do not move in the optical axis direction.

  Therefore, in the present embodiment, as shown in FIGS. 3, 5, and 8, the fixed cylinder 13 and the rotary cylinder 14 are notched 13 c (only in the range where the arm 19 a of the focus lens holding frame 19 is driven). Second cutout portion) and 14b (cutout portion) are formed. In other words, the fixed cylinder 13 and the rotary cylinder 14 are arranged so that the arm portion 19 a does not interfere with the fixed cylinder 13 and the rotary cylinder 14 in the range of movement of the focus lens holding frame 19 in the optical axis direction and the rotation range of the rotary cylinder 14. The notches 13c and 14b are respectively formed. For this reason, as shown in FIGS. 5 and 9, the drive pin 12e (second drive pin) located in the cutout portion 14b of the rotary cylinder 14 is within a range from the retracted position to the end of the cutout portion 14b. It does not engage with the rectilinear groove 14a. Note that the notch 14b does not reach the imaging area.

  Further, as shown in FIGS. 6 and 9, the rotating cylinder 14 is provided with a through hole 14 c for allowing a flexible substrate (not shown) connected to the lens holding frame 17 to pass (insert) outside the lens barrel. ing. The drive pin 12f (third drive pin) does not engage with the rectilinear groove 14a when passing through the through hole 14c.

  Here, in the present embodiment, the drive pins 12d, 12e, and 12f are arranged as a plurality of drive pins at positions equal to 120 ° on the side surface of the cam cylinder 12 (divided into three equal parts). The drive pin 12d (first drive pin) is located closest to the gear 23 (second gear portion) when retracted, and passes in front of the gear 23 in its rotation region. At this time, the engagement between the drive pin 12d and the rectilinear groove 14a is not released.

  Thus, in the rotation direction about the optical axis m, only one drive pin 12d out of the three drive pins 12d, 12e, and 12f is engaged with the rectilinear groove 14a to drive the lens barrel. Will exist. In the present embodiment, this phase coincides with the timing at which the drive pin 12d passes in front of the gear 23.

  However, as shown in FIG. 8, since the gear portion 14 d of the rotating cylinder 14 meshes with the gear 23, a force acts between the rotating cylinder 14 and the gear 23 in the direction of separating the axes. In other words, the rotary cylinder 14 is pressed in a direction to close the radial play with the fixed cylinder 13. As a result, even if the cam cylinder 12 and the rotary cylinder 14 are engaged only by the drive pin 12d, the drive pin 12d is unlikely to fall out of the rectilinear groove 14a due to the effect of backlash due to the meshing of the gears. Therefore, the driving of the lens barrel is stable.

  As described above, according to the lens barrel of the present embodiment, even when the focus motor is disposed outside the lens barrel, the lens barrel is small and thin while achieving a high magnification while achieving stable lens driving. can do. That is, there is a phase in which only one drive pin 12d is engaged with the rectilinear groove 14a, and in this phase, the drive pin 12d is positioned substantially in front of the gear 23. As a result, even if the cam cylinder 12 and the rotary cylinder 14 are engaged only by the drive pin 12d, the drive pin 12d is less likely to fall out of the rectilinear groove 14a due to the so-called backlash effect due to the meshing of the gears. Therefore, even if the focus motor 15 is disposed outside the lens barrel, it is possible to achieve a small size and a thin shape and a stable lens barrel drive with a high magnification. In addition, the size of the lens barrel in the optical axis direction can be shortened while avoiding interference between the arm portion 19a and the rotating barrel 14. In addition, the size of the lens barrel in the optical axis direction can be shortened while avoiding interference between the arm portion 19a and the fixed barrel 13.

  Further, when retracted, the drive pin 12d is in a position closest to the gear 23, and the phase coincides with the timing when the drive pin 12d passes in front of the gear 23. Therefore, the drive pin is moved forward from the retracted state. The engagement between 12d and the rectilinear groove 14a is difficult to disengage. Therefore, the effect of the backlash filling described above can be made remarkable. Moreover, a flexible substrate can be inserted into the through hole 14c formed in the side surface of the rotating cylinder 14, and electrical connection can be facilitated.

  Further, since the three drive pins 12d, 12e, and 12f are arranged on the side surface of the cam cylinder 12 that is equally divided into three (120 ° equal), the collapsing and feeding operations can be performed smoothly. . In addition, the focus motor 15 moves the focus lens holding frame 19 in the optical axis direction via the arm portion 19a by rotating the lead screw 15a in which the nut portion that contacts the arm portion 19a is screwed. As a result, the dimension in the optical axis direction that is restricted by the lead screw 15a of the focus motor 15 can also be shortened. As a result, the lens barrel can be reduced in size and thickness.

  In addition, this invention is not limited to what was illustrated to the said embodiment, In the range which does not deviate from the summary of this invention, it can change suitably. That is, the present invention is not limited to the configuration of the above-described embodiment, and any configuration can be used as long as the functions shown in the claims or the functions of the configuration of the present embodiment can be achieved. Is also applicable.

  For example, the number of drive pins arranged on the outer periphery of the cam cylinder is not limited to three, and may be two or four or more.

  In the above-described embodiment, a digital camera has been described as an example of the imaging apparatus. However, the present invention can also be applied to a digital video camera or the like.

  In addition, the lens barrel of the present embodiment is configured integrally with the imaging device, but may be attached to the imaging device in a replaceable manner.

DESCRIPTION OF SYMBOLS 1 Lens barrel 11, 17, 19 Lens holding frame 12 Cam cylinder 12d, 12e, 12f Drive pin 13 Fixed cylinder 13c, 14b Notch part 14 Rotating cylinder 14a Straight advance groove 19a Arm part 23 Gear

Claims (8)

A lens barrel that moves a first lens holding frame on which the first lens is mounted in the optical axis direction;
A cam cylinder that is provided with a first drive pin and a second drive pin on an outer periphery, and moves the first lens holding frame in an optical axis direction;
A fixed cylinder that is engaged with the outside of the cam cylinder and rotatably holds the cam cylinder;
A first rectilinear groove and a second rectilinear groove that are rotatably engaged with the outer side of the fixed cylinder and engage with the first drive pin and the second drive pin, respectively, are formed on the inner periphery in the optical axis direction. And a rotating cylinder provided with a first gear portion on the outer periphery;
A second gear part that is disposed outside the rotating cylinder, meshes with the first gear part to transmit power of the first driving part , and rotates the rotating cylinder;
It is mounted a second lens, the second lens holding frame having an arm portion extending in a direction perpendicular to the optical axis,
A second drive unit that is disposed outside the rotating cylinder and moves the second lens holding frame in the optical axis direction via the arm unit;
Of the first drive pin and the second drive pin, the first drive pin engages with the first rectilinear groove so that the second drive pin is in the rotation direction about the optical axis. There is a phase that does not engage the second rectilinear groove ,
When viewed from the front in the optical axis direction of the lens barrel, in the phase, a lens barrel, wherein a position near Rukoto that the first drive pin facing the second gear unit. A first notch is formed on a side surface of the rotating cylinder so that the arm does not interfere with the rotating cylinder in the moving range of the second lens holding frame in the optical axis direction and the rotating range of the rotating cylinder. And
In the phase, the first drive pin and of the second drive pin, the second drive pin is positioned in the first notch portion, the straight said first drive pin of the first The lens barrel according to claim 1, wherein the lens barrel engages with a groove. A second notch is formed on a side surface of the fixed cylinder so that the arm does not interfere with the fixed cylinder in a moving range of the second lens holding frame in the optical axis direction. The lens barrel according to claim 1 or 2. When the lens barrel is retracted, the first drive pin is in a position closest to the second gear portion, and the phase is determined by the second gear portion in the rotation region of the first drive pin. The lens barrel according to any one of claims 1 to 3, wherein the lens barrel coincides with a timing of passing in front of the lens. A through-hole through which a substrate connected to the second lens holding frame is inserted is formed on the side surface of the rotating cylinder,
In the phase, a lens barrel according to any one of claims 1 to 4 third driving pin provided on the outer periphery of the cam barrel, characterized in that located in the through hole. The said 1st drive pin, the said 2nd drive pin, and the said 3rd drive pin are arrange | positioned at the side surface divided into 3 equal to the circumferential direction of the said cam cylinder, The Claim 6 characterized by the above-mentioned. Lens barrel. The second drive unit has a lead screw screwed with a nut portion that comes into contact with the arm unit, and rotates the lead screw to light the second lens holding frame via the arm unit. The lens barrel according to any one of claims 1 to 6, wherein the lens barrel is moved in an axial direction.   An imaging apparatus using the lens barrel according to claim 1.