JP2006072004A - camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a camera having a retractable zoom lens and capable of reducing the dimension of an optical system in the optical axis direction when retracted.
A lens barrel 2 having first group lenses 11 and 12, second group lenses 13 and 14 and a focus lens 15 is retracted into a camera body 3 when not photographing. The first group cylinder 9 that holds the first group lenses 11 and 12 and the lens frame 16 that holds the second group lenses 13 and 14 move back and forth in the optical axis direction in conjunction with the rotation and linear movement of the cam cylinder 7. When the cam cylinder 7 rotates while retracting and retracts along the optical axis direction, the convex portion formed at the rear end of the cam cylinder 7 engages the side surface of the lens frame 17 of the focus lens 15. After this engagement, the lens barrel 17 is driven to rotate about the guide shaft 23 by the rotation of the cam barrel 7, and the lens frame 17 rides on the side surface of the cam barrel 7. As a result, the focus lens 15 is retracted out of the retracted region of the cam cylinder 7.
[Selection] Figure 1

Description

  The present invention relates to a retractable camera.

  A lens barrel-integrated camera is often a collapsible camera in which the lens barrel is retracted into the camera body in order to reduce the size of the camera when not photographing (see, for example, Patent Document 1). .

JP-A-9-203842

  However, in the above-described camera, since the lens group in the lens barrel is moved in the optical axis direction and the lens barrel is retracted in the camera body, the thickness at the time of retracting is the thickness of the lens and the clearance. It was not smaller than the sum of

The invention of claim 1 is applied to a camera having a plurality of lens groups including a focus lens group and having a zoom lens in which a lens barrel is retracted in the camera body. A retracting mechanism for retracting out of the retracted region of the cylinder is provided, and other lens groups other than the focus lens group are moved to the pre-retracted region of the focus lens group.
The invention of claim 2 is applied to a camera having a plurality of lens groups including a focus lens group, and a zoom lens whose lens barrel is retracted in the camera body, and at least one lens group excluding the focus lens group And a cam cylinder that rotates during retraction and retreats along the optical axis direction while being retracted, and a holding member that is provided in the cam cylinder and holds the focus lens group during retraction. An engaging portion for driving the holding member by rotation of the cam cylinder to retract the focus lens group out of the retracted area of the cam cylinder, and other lens groups excluding the focus lens group in the area before retraction of the focus lens group It is characterized by moving.
According to a third aspect of the present invention, in the camera according to the second aspect of the present invention, a lead screw and a rack in which a part of the female screw to be screwed to the lead screw is formed and connected to the holding member, and the holding member is arranged in the optical axis direction. When the lens is not retracted, the rack contacts and engages with the lead screw. When the lens is retracted, the holding portion is driven by the engaging portion so that the rack is separated from the lead screw and the threaded state is released. It is what I did.

  According to the present invention, when the lens barrel is retracted, the focus lens group is retracted out of the retractable region of the lens barrel or the cam barrel, so that the stacked size of the lens group on the optical axis at the time of retracting can be made smaller than before. The camera can be made thinner.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings. 1 and 2 are sectional views showing the structure of the optical system of the camera according to the present invention. The camera 1 of the present embodiment is a retractable digital still camera, and FIG. 1 shows a shooting state in which the lens barrel 2 is extended forward. On the other hand, FIG. 2 shows a non-photographing state in which the power is turned off, and the lens barrel 2 is retracted in the body 3. An imaging device 5 and a lens barrel 2 are fixed to a base 4 provided in the body 3. In the imaging device 5, a CCD imaging device or the like is used as an imaging device, and an optical low-pass filter is disposed in front of the imaging device in the imaging device 5.

  The lens barrel 2 is provided with a fixed cylinder 6 fixed to the base 4, a cam cylinder 7, a rectilinear cylinder 8, and a first group cylinder 9 that rotate relative to the fixed cylinder 6 and move forward and backward in the optical axis direction. The lens barrel 2 is fixed to the base 4 by fixing the fixed cylinder 6 to the base 4 with screws 10. The first group cylinder 9 holds lenses 11 and 12 constituting a first group lens. The lenses 13 and 14 held in the lens frame 16 constitute a second group lens, and the lens frame 17 holds a focus lens 15 constituting a third group lens.

  A shutter unit 18 for operating the shutter blades 18 a is fixed to the lens frame 16 with screws 19. A cam pin 20 is provided on the outer peripheral surface of the cam cylinder 7, and the cam pin 20 is engaged with a cam groove 6 a formed on the inner peripheral surface of the fixed cylinder 6. Therefore, when the cam cylinder 7 is rotationally driven by a motor (not shown), the cam cylinder 7 advances and retracts in the optical axis direction with respect to the fixed cylinder 6.

  The rectilinear cylinder 8 is provided so as to be inserted into the cam cylinder 7 and is rotatably connected to the cam cylinder 7 at the rear end portion 8a. A radially projecting key 8 b is formed at the rear end of the rectilinear cylinder 8, and the key 8 b is engaged with a key groove 6 b formed on the inner peripheral surface of the fixed cylinder 6. The key groove 6b is formed along the optical axis direction. Therefore, when the cam cylinder 7 is rotated, the rectilinear cylinder 8 advances and retreats in the optical axis direction integrally with the cam cylinder 7, but the key 8b is engaged with the key groove 6b. Rotational movement is prevented.

  A cam pin 21 is provided on the outer peripheral surface of the first group cylinder 9 inserted in the rectilinear cylinder 8, and the cam pin 21 is engaged with a cam groove 7 a formed on the inner peripheral surface of the cam cylinder 7. A cam groove 7b different from the cam groove 7a is formed on the inner peripheral surface of the cam cylinder 7, and a cam pin 22 provided on the lens frame 16 is engaged with the cam groove 7b.

  The cam pins 21 and 22 are engaged with a rectilinear groove 8c formed in the rectilinear cylinder 8 and extending in the optical axis direction. Therefore, when the cam cylinder 7 is rotated, the cam pins 21 and 22 are guided by the cam grooves 7a and 7b, respectively, and the first group cylinder 9 and the lens frame 16 are advanced and retracted in the optical axis direction.

  The lens frame 17 that holds the focus lens 15 is slidably provided on a guide shaft 23 extending in the optical axis direction, and can swing around the guide shaft 23. The guide shaft 23 is provided so as to be spanned between the flange portion of the fixed cylinder 6 and the base 4. A rack member 25 is rotatably provided on the shaft 24 provided in the lens frame 17. The rack member 25 is formed with a rack 25 a that engages with the lead screw 28. The rack 25 a constitutes a part of the female screw that is screwed into the male screw of the lead screw 28.

  The torsion compression spring 26 urges the rack member 25 in the left direction in the drawing and urges the rack member 25 to rotate in the direction of the lead screw 28 by a torsional force. Therefore, in the photographing state shown in FIG. 1, the rack 25 a is screwed to the lead screw 28 by the twisting force of the twist compression spring 26.

  The lens frame 17 is urged in the left direction in the figure and is urged in the R1 direction in FIG. 1 by a torsion compression spring 27 provided on the guide shaft 23. When the lead screw 28 is rotationally driven by the motor 29, the focus lens 15 held by the lens frame 17 advances and retreats in the optical axis direction, and focus adjustment is performed.

  The shaft 30 provided in the lens frame 17 is provided to prevent the rack member 25 from rotating more than necessary when the focus lens 15 is retracted from the optical axis in a non-photographing state. It is. Reference numeral 31 denotes a positioning member for the lens frame 17. In the photographing state of FIG. 1, the lens frame 17 is urged to rotate in the R 1 direction by the torsion compression spring 27 and is in contact with the positioning member 31.

  When the power-off operation is performed in the photographing state shown in FIG. 1, a retracting operation for retracting the lens barrel 2 into the body 3 is performed. When the cam cylinder 7 is retracted in the R2 direction during the retracting operation, the rear end of the cam cylinder 7 comes into contact with the lens frame 17, and the lens frame 17 is rotated in the direction opposite to the arrow R1. In the retracted state shown in FIG. 2, the lens frame 17 that holds the focus lens 15 is retracted to the outer region of the cam cylinder 7.

<Explanation of focus lens retracting action>
FIG. 3 is a view showing the rear end shape of the cam cylinder 7, and is a perspective view of the cam cylinder 7 viewed from the rear end side. As described above, the cam pin 20 is provided on the outer peripheral surface of the cam cylinder 7. A convex portion 7 c for retracting the lens frame 17 is formed on the rear end surface of the cam cylinder 7. During the collapsing operation, the cam cylinder 7 moves backward in the R4 direction, which is the camera rear direction, while rotating in the R3 direction.

  FIG. 4 is a diagram for explaining the retraction operation of the lens frame 17 holding the focus lens 15, and the operation proceeds in the order from (a) to (c). FIG. 4A shows the arrangement of the lens frame 17 in the shooting state of FIG. In this state, the convex portion 7 c of the cam cylinder 7 is not in contact with the side surface 17 a of the lens frame 17. When the cam cylinder 7 is rotated by an angle θ1 in the R3 direction from the state of FIG. 4A, the convex portion 7c formed at the rear end of the cam cylinder 7 comes into contact with the side surface 17a.

  When the cam cylinder 7 further rotates, the lens frame 17 starts to rotate in the R1 direction around the guide shaft 23. FIG. 4B shows a state where the cam cylinder 7 is further rotated by an angle θ2 after the convex portion 7c contacts the side surface 17a of the lens frame 17. FIG. When the lens frame 17 rotates clockwise (R1 direction) about the guide shaft 23, the rack member 25 is biased to rotate counterclockwise by the torsion compression spring 26, and therefore the rack member 25 is pivoted. The lead screw 28 is screwed in until it abuts 30. However, since the rack member 25 rotates clockwise (R1 direction) together with the lens frame 17 after the rack member 25 contacts the shaft 30, the rack member 25 is removed from the lead screw 28 as shown in FIG. I will leave.

  When the cam cylinder 7 further rotates from the state of FIG. 4B, the lens frame 17 is further rotated by the convex portion 7c, and the lens frame 17 is pushed out of the cam cylinder 7 as shown in FIG. 4C. It rides on the outer peripheral surface of the cam cylinder 7. As a result, the focus lens 15 is completely retracted from the optical axis. FIG. 4C shows the positional relationship between the cam cylinder 7 and the lens frame 17 in the retracted state shown in FIG. When the lens barrel 2 is extended from the retracted state of FIG. 2 to the state of FIG. 1, the cam barrel 7 rotates in the direction opposite to the R3 direction (see FIG. 3), and the procedure completely opposite to the above-described operation is performed. Will follow. In this case, as shown in FIG. 4A, the lens frame 17 contacts the positioning member 31, whereby the focus lens 15 is positioned at a predetermined position on the optical axis.

  As shown in FIG. 3, the cam cylinder 7 advances straight in the R4 direction (camera rear side) while rotating in the R3 direction. Therefore, the height H (see FIG. 3) of the convex portion 7c is set such that the convex portion 7c contacts the lens frame 17 as shown in FIG. 4A and the outer peripheral surface of the cam cylinder 7 as shown in FIG. If the distance is set to be greater than the linear movement distance until the vehicle rides on the lens frame 17, the lens frame 17 rotates around the guide shaft 23 without moving backward. On the other hand, when the height H is set to be smaller than the rectilinear movement distance of the cam barrel 7, the lens frame 17 is not only rotated around the guide shaft 23, but is also pushed by the rear end of the cam barrel 7 and the back of the camera. Retreat to the side.

  As described above, since the focus lens 15 that is the third group lens is retracted to the outside of the cam cylinder 7 in the retracted state, the second group lenses 13 and 14 are placed immediately before the imaging device 5 as shown in FIG. Can be moved back up. That is, the thickness of the lens system in the optical axis direction can be reduced by the amount corresponding to the third group lens. In addition, since the focus lens 15 is retracted by utilizing the backward movement of the cam cylinder 7, it is not necessary to add a special mechanism such as a retracting motor, and an increase in parts can be suppressed.

  In the above-described embodiment, the digital still camera has been described as an example, but the present invention can be similarly applied to a zoom type camera (for example, a silver salt camera) other than the digital still camera. In addition, the present invention is not limited to the above embodiment as long as the characteristics of the present invention are not impaired.

  In the correspondence between the embodiment described above and the elements of the claims, the lens frame 17 rotatable around the cam cylinder 7 and the guide shaft 23 having the convex portion 7c is a retracting mechanism, and the lens frame 17 is a holding member. And the convex portion 7c constitutes an engaging portion.

It is sectional drawing which shows schematic structure of the camera by this invention, and shows an imaging | photography state. It is sectional drawing which shows the non-photographing state into which the lens-barrel 2 of the camera 1 will be a retracted state. It is the perspective view which looked at the cam cylinder 7 from the rear end side. It is a figure explaining the retraction | saving operation | movement of the lens frame 17 holding the focus lens 15, and operation | movement progresses in order from (a) to (c).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Camera 2 Lens barrel 3 Body 4 Base 5 Imaging device 6 Fixed cylinder 7 Cam cylinder 7c Convex part 8 Straight advance cylinder 9 1st group cylinder 11-14 Lens 15 Focus lens 16, 17 Lens frame 23 Guide shaft 25 Rack member 26, 27 Twist Compression spring 28 lead screw

Claims (3)

In a camera having a zoom lens in which a lens barrel is retracted into a camera body having a plurality of lens groups including a focus lens group,
A retracting mechanism for retracting the focus lens group to the outside of the retracted region of the lens barrel when retracted, and moving other lens groups except the focus lens group to a region before retracting the focus lens group; Camera. In a camera having a zoom lens in which a lens barrel is retracted into a camera body having a plurality of lens groups including a focus lens group,
A cam cylinder that moves at least one lens group excluding the focus lens group in the optical axis direction by cam driving and retreats along the optical axis direction while rotating when retracted;
The cam cylinder is engaged with a holding member that holds the focus lens group when retracted, and the holding member is driven by rotation of the cam cylinder to move the focus lens group outside the retracted area of the cam cylinder. And a retracting engagement portion, wherein a lens group other than the focus lens group is moved to a pre-retraction area of the focus lens group. The camera according to claim 2,
A lead screw and a rack formed with a part of the female screw to be screwed to the lead screw and connected to the holding member, and a focus drive mechanism for driving the holding member in the optical axis direction;
When not retracted, the rack comes into contact with and screwed with the lead screw, and when retracted, the holding portion is driven by the engaging portion so that the rack is separated from the lead screw and the screwed state is released. Camera.

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