JP2004126029A - Collapsible mount type lens barrel and its assembling method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a collapsible mount type lens barrel which is adaptable to high magnification and whose assemblage efficiency is improved, and its assembling method. <P>SOLUTION: The cam grooves 18a, 18b and 18c of a cam frame 17 are provided with a wide part 19d whose width in the optical axis direction is made larger than other parts so that the cam pins 16a, 16b and 16c of a driving frame 15 may not be engaged in the cam grooves 18a, 18b and 18c of the frame 17 when the collapsible mount type lens barrel 1 is collapsed. In the case of assembling the lens barrel 1, the damage of the pins 16a, 16b and 16c and the grooves 18a, 18b and 18c is prevented by moving the pins 16a, 16b and 16c to the wide parts 19d and screwing and fixing them. Since parts are assembled from one direction, assemblage man-hours are reduced. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a collapsible lens barrel that has a reduced length of a lens barrel during non-photographing compared to that during photography and is excellent in portability, and a method of assembling the same.
[0002]
[Prior art]
2. Description of the Related Art In recent years, digital still cameras (hereinafter, referred to as DSCs) that can immediately confirm a captured image have been rapidly spread. As a lens barrel for this DSC, a so-called collapsible lens barrel in which the length of the lens barrel is shortened during non-photographing is generally adopted in consideration of portability during non-photographing. .
[0003]
FIG. 17 shows an exploded perspective view of a conventional collapsible lens barrel (for example, see Patent Document 1). The collapsible lens barrel 60 is an optical system that changes the focal length by moving the movable lens frames 62 and 63 in the front-rear direction by one cam cylinder 61. Cam grooves 64, 65 are formed on the inner peripheral surface of the cam cylinder 61, and the cam grooves 64, 65 determine the movement trajectories of the movable lens frames 62, 63, respectively. The movable lens frames 62 and 63 move in the optical axis (Z-axis) direction when three cam pins 62a and 63a provided on the respective outer peripheral surfaces engage with the cam grooves 64 and 65, respectively. The cam cylinder 61 is provided outside the fixed cylinder 70 and is rotatable around the optical axis. A gear 66 is formed on the outer periphery of the cam cylinder 61, and a driving force transmission gear 67 meshes with the gear 66. The driving force transmission gear 67 is connected to an output shaft of a cam cylinder driving actuator 69 via a reduction gear train 68. Therefore, when the cam cylinder driving actuator 69 is driven, the driving force is transmitted to the driving force transmission gear 67 via the reduction gear train 68, and the cam cylinder 61 is rotated. As a result, the movable lens frames 62 and 63 move along the shapes of the cam grooves 64 and 65, respectively, so that zooming is performed from the collapsed state via the wide-angle end.
[0004]
[Patent Document 1]
JP, 2002-107598, A
[Problems to be solved by the invention]
However, the above-mentioned conventional collapsible lens barrel has the following problems.
[0006]
1. When assembling the retractable lens barrel, it is necessary to assemble the lens barrel from at least two directions, which increases the number of assembling steps. The assembling method in the retractable lens barrel shown in FIG. 17 is as follows. First, the movable lens frames 62 and 63 are assembled to the fixed frame 70 from the front side (the object side) of the fixed frame 70. Next, the cam cylinder 61 is assembled to the fixed frame 70 from the rear side of the fixed frame 70, and the cam pins 62a, 63a provided on the movable lens frames 62, 63 and the cam grooves 64, 65 are engaged. . Further, a fixing screw is tightened from the rear side of the fixing frame 70. Therefore, when assembling, it is necessary to assemble while changing the direction of the lens barrel, and the assembling method is complicated.
[0007]
2. The compressive load applied to the lens barrel when the fixing frame 70 is tightened with a screw acts on the contact portions between the cam pins 62a, 63a and the cam grooves 64, 65, and these are damaged.
[0008]
3. In the above-mentioned conventional collapsible lens barrel, since zooming is performed using the reduction gear train 68 and the cam frame (cam cylinder 61), it is not suitable for increasing the zoom speed and reducing the noise of the zoom sound. It is.
[0009]
SUMMARY OF THE INVENTION It is an object of the present invention to provide a collapsible lens barrel with high magnifying power, which has improved assemblability and does not cause damage to parts during assembling, and a method of manufacturing the same. Still another object of the present invention is to provide a collapsible lens barrel capable of realizing a higher zoom speed and a quieter zoom sound by performing zooming without using a cam frame.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, a collapsible lens barrel according to the present invention includes a holding frame for holding a photographing lens group, a cylindrical cam frame having a plurality of cam grooves formed therein, and an engagement with the cam grooves. An engaging means is provided, and by rotating relative to the cam frame about the optical axis as a center of rotation, a substantially hollow cylindrical drive frame that interlocks with the holding frame in the optical axis direction, Driving means for extending the photographing lens group toward the object side and moving the photographing lens group to the image plane side during non-shooting, wherein the engaging means is arranged in a state where the photographing lens group is moved to the most image plane side. A wide portion having an increased width in the optical axis direction is formed in the cam groove so that the cam groove does not come into contact with the cam groove.
[0011]
According to the retractable lens barrel of the present invention, in the retracted state, even if a compressive load is applied in the optical axis direction, the engaging means does not come into contact with the cam groove. Damage to the lens barrel such as damage to the lens barrel can be prevented.
[0012]
In addition, as a collapsing actuator separate from the zooming drive actuator, a drive means is provided to extend the photographing lens group toward the object side during photographing, and to move the photographing lens group toward the image plane during non-photographing. It is not driven, so that the zoom time can be increased and the zoom noise can be reduced.
[0013]
Next, a method of assembling the retractable lens barrel of the present invention is the method of assembling the retractable lens barrel of the present invention, wherein the first assembling step of assembling the holding frame and the drive frame, A second assembly step of assembling the drive frame and the cam frame by engaging the engagement means with the cam groove; and moving the engagement means of the drive frame to the wide portion of the cam groove. A third assembling step; and a fourth assembling step of fixing the fixed frame holding the driving means to the cam frame, wherein all of the first to fourth assembling steps are performed from the same direction. And
[0014]
According to the collapsible lens barrel assembling method of the present invention, all parts are assembled from the same direction, so that the number of assembling steps can be reduced and the cost of the lens barrel can be reduced.
[0015]
Further, since the fourth assembling step of fixing the fixing frame to the cam frame is performed in a state where the engaging means is moved to the wide portion of the cam groove, the compressive load in the optical axis direction is reduced at the time of the fourth assembling step. Even if it is added to the lens barrel, since the engaging means and the cam groove are not in contact with each other, inconveniences such as deformation of the engaging means and damage to the cam groove do not occur.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a collapsible lens barrel and an assembling method thereof according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is an exploded perspective view of a collapsible lens barrel according to the present embodiment, FIG. 2 is an exploded perspective view illustrating a guide pole support portion of the collapsible lens barrel, and FIGS. 3 (a), (b), and ( 4C is a view for explaining the inclination of the lens in the retractable lens barrel, FIG. 4 is a development view of a cam groove in the retractable lens barrel, and FIGS. 5A and 5B are the retractable lens barrel. , FIG. 6 is an exploded perspective view of a cam frame in the collapsible lens barrel, FIG. 7 is a flowchart showing a method of assembling the collapsible lens barrel, and FIG. FIG. 9 is a perspective view for explaining a first assembling step of the method for assembling the retractable lens barrel, FIG. 9 is a perspective view for explaining a second assembling step of the method for assembling the retractable lens barrel, and FIG. Third assembling method of collapsible lens barrel FIG. 11 is a perspective view for explaining a fourth assembling step of the method for assembling the retractable lens barrel, and FIG. 12 is a cam pin and cam in a fourth assembling step of the retractable lens barrel. FIG. 13 is a cross-sectional view illustrating the engagement state of the groove, FIG. 13 is a perspective view illustrating a method of fixing the flexible print cable in the method of assembling the collapsible lens barrel, and FIG. 14 is a cross-section of the collapsible lens barrel when collapsible. 15 and FIG. 15 are cross-sectional views of the retractable lens barrel when the telephoto end is used, and FIG. 16 is a cross-sectional view of the retractable lens barrel when the wide-angle end is used.
[0017]
The retractable lens barrel 1 and an assembling method thereof will be described with reference to FIGS. As shown in the drawing, an XYZ three-dimensional orthogonal coordinate system is set in which the optical axis of the retractable lens barrel is the Z axis (the object side is positive). L1 is a first-group lens, L2 is a second-group lens that moves on the optical axis (Z-axis) to perform zooming, L3 is a third-group lens for image blur correction, and L4 is a lens for correcting image plane fluctuation due to zooming. The fourth lens group moves on the optical axis for focusing.
[0018]
The first-group holding frame 2 holds the first-group lens L1, and is fixed to the cylindrical first-group moving frame 3 with screws or the like so that the central axis of the first-group lens L1 is parallel to the optical axis. I have. One end of two guide poles (guide members) 4a, 4b parallel to the optical axis is fixed to the first group moving frame 3.
[0019]
The second group moving frame 5 holds the second group lens L2 and is slidable in the optical axis direction by being supported by the two guide poles 4a and 4b described above. The second group moving frame 5 is engaged with a feed screw 6a of a second group lens driving actuator 6 such as a stepping motor and a screw portion of a rack 7 provided on the second group moving frame 5 so that the second group lens driving actuator 6 With the driving force described above, the lens is moved in the optical axis direction to perform zooming.
[0020]
The third group frame 8 holds an image blur correction lens group L3 (third group lens), and forms an image blur correction device 31.
[0021]
The fourth group moving frame 9 is slid in the optical axis direction by being supported by two guide poles 11a and 11b parallel to the optical axis and sandwiched between the third group frame 8 and the master flange 10. It is possible. Further, the fourth group moving frame 9 is engaged with a feed screw 12a of a fourth group lens driving actuator 12 such as a stepping motor and a screw portion of a rack 13 provided on the fourth group moving frame 9 so as to be engaged. Is moved in the direction of the optical axis by the driving force, and correction and focusing of the image plane fluctuation due to zooming are performed.
[0022]
The image pickup device (CCD) 14 is attached to the master flange 10.
[0023]
Next, a method of supporting the guide poles 4a and 4b will be described with reference to FIG.
[0024]
The third group frame 8 is provided with support portions 8a (main shaft side) and 8b (rotation stop side). When the guide poles 4a and 4b penetrate the support portions 8a and 8b, the guide poles 4a and 4b are held parallel to the optical axis. Since the guide poles 4a and 4b slide in the optical axis direction with respect to the two support portions 8a and 8b, the first group lens L1 held by the first group moving frame 3 fixed to one end of the guide poles 4a and 4b. Is maintained with respect to the image blur correction lens L3 provided in the third group frame 8. Further, the guide poles 4a and 4b slidably penetrate the support portions 5a (rotation-stop side) and 5b (main shaft side) provided on the second group moving frame 5, so that the second group moving frame 5 Since the second group lens L2 held by the second group moving frame 5 is supported by the second group moving frame 5 with respect to the image blur correcting lens L3 provided in the third group frame 8, the lens is supported by the slidable optical axis directions 4a and 4b. Is kept.
[0025]
Here, the relationship between the first group lens L1, the second group lens L2, and the third group lens L3 described above will be described with reference to FIGS. 3 (a) to 3 (c). In the figure, arrows L1a and L2a indicate the directions of the central axes of the first group lens L1 and the second group lens L2, respectively.
[0026]
FIG. 3A shows an ideal state of the three lens units L1, L2, and L3, with respect to the Z axis (the optical axis of the lens barrel, which coincides with the central axis of the third lens unit L3). The center axis L1a of the first lens unit L1 and the center axis L2a of the second lens unit L2 are parallel to each other.
[0027]
FIG. 3B shows a cam lens 62a and a movable lens frame 63 provided on the movable lens frame 62 of FIG. 17 by using the same method as the conventional lens barrel shown in FIG. 3 shows a case where each cam pin 63a is supported by a corresponding one of the cam pins 63a. In this case, due to variations in the accuracy of the cam pins 62a and 63a and the cam grooves 64 and 65, the central axis L1a of the first lens group L1 and the central axis L2a of the second lens group L2 are not parallel to each other and are also parallel to the Z axis. Not be. Therefore, there is a high possibility that the optical performance is deteriorated.
[0028]
FIG. 3C shows the case of the present embodiment. Since the first group lens L1 and the second group lens L2 are supported by the same guide poles 4a and 4b, the center axis L1a of the first group lens L1 and the center axis L2a of the second group lens L2 are temporarily inclined with respect to the Z axis. Even if it does, the directions of both central axes L1a and L2a always coincide. That is, the first lens unit L1 and the second lens unit L2 are always tilted in the same direction with respect to the image blur correction lens unit L3 having the highest influence on the optical performance, so that the deterioration amount of the optical performance can be minimized. .
[0029]
Next, a configuration for moving the first lens unit L1 in the optical axis direction will be described.
[0030]
A gear 15a is formed on a part of the inner peripheral surface of the substantially hollow cylindrical drive frame 15 on the image sensor 14 side. Also, three projections 15b are formed on the inner peripheral surface on the object side (positive side of the Z axis) at intervals of approximately 120 °. When the protrusion 15b engages with three circumferential grooves 3a provided on the outer peripheral surface of the first group moving frame 3 on the image sensor 14 side, the drive frame 15 moves the optical axis with respect to the first group moving frame 3. The drive frame 15 and the first-group moving frame 3 move integrally in the optical axis direction. Further, three cam pins 16a, 16b, 16c are press-fitted and fixed at 120 ° intervals on the inner peripheral surface of the drive frame 15.
[0031]
On the outer surface of the cylindrical cam frame 17, three cam grooves 18a, 18b and 18c are formed at intervals of about 120 °. FIG. 4 is a development view of the outer peripheral surface of the cam frame 17. The cam pins 16a, 16b, 16c of the drive frame 15 engage with the cam grooves 18a, 18b, 18c of the cam frame 17, respectively. Each of the cam grooves 18a, 18b, 18c has a portion 19a substantially parallel to the circumferential direction of the cam frame 17 on the image sensor 14 side (negative side of the Z axis) and a cam frame on the object side (positive side of the Z axis). 17 has a portion 19c that is substantially parallel to the circumferential direction, a portion 19b that helically connects the portions 19a and 19c, and a wide portion 19d whose width is increased in the Z-axis direction at the end of the portion 19a. When the cam pins 16a, 16b, and 16c are in the portion 19a, the first lens unit L1 stops in a state of being retracted toward the image sensor 14 (retracted state). From this state, when the drive frame 15 rotates around the optical axis, the cam pins 16a, 16b, and 16c reach the portion 19c via the portion 19b. When the cam pins 16a, 16b, 16c are in the portion 19c, the first lens unit L1 is extended toward the object side and stopped.
[0032]
The cam groove 18 is formed such that the width in the optical axis direction differs depending on the extension position of the drive frame 15. This will be described with reference to FIG.
[0033]
FIG. 5A shows the cam pins 16a, 16b, 16c and the cam grooves 18a, 18b, 18c at the portions 19a, 19b, 19c of the cam grooves 18a, 18b, 18c in a direction parallel to the Z axis. It is a partial sectional view. As illustrated, in the portions 19a, 19b, and 19c, the cam grooves 18a, 18b, and 18c are formed to be wider by about several micrometers in the Z-axis direction than the cam pins 16a, 16b, and 16c. , 16b, 16c can slide smoothly in the cam grooves 18a, 18b, 18c.
[0034]
FIG. 5B is a partial cross-sectional view in the direction parallel to the Z axis, showing the cam pins 16a, 16b, 16c and the cam grooves 18a, 18b, 18c in the wide portions 19d of the cam grooves 18a, 18b, 18c. It is. As shown, in the wide portion 19d, the cam grooves 18a, 18b, 18c are connected to the cam pins 16a, 16b, 16c so that the cam pins 16a, 16b, 16c do not contact the cam grooves 18a, 18b, 18c in the Z-axis direction. On the other hand, the width is increased in the Z-axis direction. As a result, in a state where the drive frame 15 is retracted most toward the image plane side (a state of FIG. 14 described later), the cam pins 16a, 16b, and 16c are in the wide portion 19d, and as shown in FIG. The cam pins 16a, 16b, 16c do not contact the cam grooves 18a, 18b, 18c.
[0035]
Between the cam groove 18b and the cam groove 18c on the outer peripheral surface of the cam frame 17, a bearing portion 17d rotatably holding the drive gear shafts 20 at both ends of the spline-shaped drive gear 19, and a drive gear 19 A drive gear mounting portion (recess) 17a recessed into a semi-cylindrical surface is formed to avoid interference with the drive gear 19, whereby the drive gear 19 is rotatably held on the outer peripheral surface of the cam frame 17. I have. The drive gear 19 transmits a driving force of a drive unit 21 attached to the master flange 10 described later to a gear portion 15 a provided on the drive frame 15. Therefore, the rotation of the drive gear 19 causes the drive frame 15 to rotate around the optical axis. At this time, the cam pins 16a, 16b, 16c provided on the drive frame 15 are moved by the cam grooves 18a, 18b of the cam frame 17. , 18c, the drive frame 15 also moves in the optical axis direction. At this time, the rotation of the first group moving frame 3 around the optical axis is restricted by the two guide poles 4a, 4b fixed to the first group moving frame 3 penetrating the support portions 8a, 8b of the third group frame 8. Therefore, as the drive frame 15 moves in the optical axis direction, the first group moving frame 3 moves straight in the optical axis direction.
[0036]
The drive actuator 6 of the second group moving frame 5 is fixed to the mounting portion 17b of the cam frame 17. The drive actuator 12 of the fourth group moving frame 9 is fixed to the mounting portion 10a of the master flange 10. The drive unit 21 for transmitting the driving force to the drive gear 19 includes a drive actuator 22 and a reduction gear unit 23 composed of a plurality of gears, and is fixed to the mounting portion 10b of the master flange 10.
[0037]
As shown in FIG. 6, the second group lens drive actuator 6 is attached to the attachment portion 17b of the cam frame 17. The origin detection sensor 25 of the second group lens L2 is attached to the attachment part 17c of the cam frame 17, and the blade 5c provided on the second group moving frame 5 passes through the front of the origin detection sensor 25 and blocks light so that the origin is detected. Is detected. The drive gear 19 is attached to the bearing 17d of the cam frame 17 and the drive gear attachment (recess) 17a, as described above.
[0038]
The shutter unit 24 includes an aperture blade and a shutter blade having a constant aperture diameter for controlling the exposure amount and the exposure time of the image sensor 14.
[0039]
The origin detection sensor 25 for the second group moving frame 5 is a light detection sensor including a light emitting element and a light receiving element, and detects the position of the second group moving frame 5 in the optical axis direction, that is, the origin position of the second group lens L2. The origin detection sensor 26 for the fourth group moving frame 9 detects the position of the fourth group moving frame 9 in the optical axis direction, that is, the origin position of the fourth group lens L4. The origin detection sensor 27 for the drive frame 15 detects the position of the drive frame 15 in the rotation direction, that is, the origin position of the first-group moving frame 3 and the first-group lens L1 that move together with the drive frame 15.
[0040]
The image blur correction device 31 adjusts the image blur correction lens group L3 for correcting image blur at the time of shooting by pitching in the first direction (Y direction) and yawing in the second direction (X direction). Move in the direction and. The first electromagnetic actuator 41y generates a driving force in the Y direction, and the second electromagnetic actuator 41x generates a driving force in the X direction. , Y.
[0041]
The collapsible lens barrel 1 configured as described above is assembled by sequentially performing steps S1 to S6 shown in FIG. Hereinafter, each step will be described in order.
[0042]
(First assembly step S1)
As shown in FIG. 8, the guide poles 4a and 4b fixed to the first group moving frame 3 are inserted into the supporting portions 5a and 5b of the second group moving frame 5, respectively. Further, the protrusion 15b provided on the drive frame 15 is engaged with the groove 3a provided on the first group moving frame 3, and the drive frame 15 is rotated in the direction of the arrow.
[0043]
(Second assembly step S2)
As shown in FIG. 9, the cam pins 16a, 16b, 16c protruding from the inner wall surface of the drive frame 15 are engaged with the cam grooves 18a, 18b, 18c provided on the outer peripheral surface of the cam frame 17.
[0044]
(Third assembly step S3)
As shown in FIG. 10, the drive frame 15 is rotated in the direction of the arrow. Since the cam pins 16a, 16b, 16c are engaged with the cam grooves 18a, 18b, 18c, the rotation of the drive frame 15 causes the cam frame 17 to move in the Z-axis direction and is stored in the drive frame 15. . By the rotation of the drive frame 15, the cam pins 16a, 16b, 16c move to the position of the wide portion 19d at the end of the cam grooves 18a, 18b, 18c. Next, the guide poles 4a and 4b are inserted into the support portions 8a and 8b of the third group frame 8 on which the image blur correction device 31 is mounted.
[0045]
(Fourth assembly step S4)
As shown in FIG. 11, after inserting the guide poles 11a and 11b (not shown) and the fourth-group moving frame 9 behind the third-group frame 8, the master flange 10 is assembled. Then, the cam frame 17, the third group frame 8, and the master flange 10 are fixed with three screws 35 from the rear side of the master flange 10.
[0046]
The engagement state between the cam pins 16a, 16b, 16c and the cam grooves 18a, 18b, 18c in the fourth assembling step will be described with reference to FIG. The screwing of the lens barrel 1 is performed by contacting the object-side end face 3b of the first-group moving frame 3 with the installation surface 80 with the first-group lens L1 on the lower side. At the time of screwing, a downward load F acts on the cam frame 17. At this time, the cam pins 16a, 16b, 16c are located at the positions of the wide portions 19d at the ends of the cam grooves 18a, 18b, 18c. Therefore, even when the load F acts, the cam pins 16a, 16b, and 16c do not come into contact with the cam grooves 18a, 18b, and 18c, and the load F is applied to the ring-shaped portion protruding from the inner surface of the first group moving frame 3. The end surface 3c on the image plane side and the end surface 17d on the object side of the cam frame 17 are in contact with and supported. Therefore, the load F acts on the cam pins 16a, 16b, 16c and the cam grooves 18a, 18b, 18c at the time of screwing, and the cam pins 16a, 16b, 16c are deformed or the cam grooves 18a, 18b, 18c are damaged. Inconvenience such as does not occur.
[0047]
(Fifth assembly step S5)
The second lens drive actuator 6 is fixed to the cam frame 17, and the first lens drive actuator 22 and the fourth lens drive actuator 12 are fixed to the master flange 10.
[0048]
(Sixth assembly step)
As shown in FIG. 13, a flexible printed cable 37 for the image blur correction device 31 and a flexible printed cable 38 for the shutter unit 24 are soldered to an electric board (flexible printed wiring board) 36 attached to the master flange 10. The attachment portions 36a and 37a, and 36b and 38a are joined together and fixed by soldering. Then, the image sensor 14 is fixed to the fixing portion 10c of the master flange 10.
[0049]
Thus, the assembling of the retractable lens barrel 1 is completed.
[0050]
Next, the operation of the collapsible lens barrel 1 configured as described above will be described below.
[0051]
First, the operation of the collapsible lens barrel 1 is changed from the non-photographing state (when not in use) shown in FIG. 14 to the photographing state shown in FIG. 16 (wide-angle end) through the state shown in FIG. The operation at the time of shifting to the state will be described.
[0052]
When the power switch and the like of the camera body are turned on from the state at the time of non-photographing in FIG. First, the first-group lens drive actuator 22 that drives the first-group lens L1 rotates, and rotates the drive gear 19 via the reduction gear unit 23. As the drive gear 19 rotates, the drive frame 15 meshing with the drive gear 19 rotates about the optical axis along the cam grooves 18a, 18b, 18c. After the origin detection sensor 27 is initialized, the drive frame 15 moves in the object direction (Z-axis direction), so that the first-group moving frame 3 also moves in the object direction. When a rotation amount detection sensor (not shown) detects that the first lens drive actuator 22 has rotated by a predetermined rotation amount, the first lens group moving frame 3 moves to a predetermined position, and then the first lens drive actuator 22 Rotation stops. At this stop position, the cam pins 16a, 16b, 16c have reached a portion 19c substantially parallel to the circumferential direction of the cam frame 17 in the developed view of the cam groove in FIG. FIG. 15 shows the state at this time.
[0053]
Next, in order to move the second group lens L2, which is a zooming lens, to a predetermined position, the second group lens drive actuator 6 is rotated, and the rack 7 is driven via the feed screw 6a. Start moving along the Z axis. Then, after initializing the origin detection sensor 25, it moves in the direction of the object, the second-group moving frame 5 stops at the position at the wide-angle end shown in FIG. 16, and the camera body is ready for shooting. Here, the first group moving frame 3 and the second group moving frame 5 move to predetermined positions while being supported by the same guide poles 4a, 4b held by the support portions 8a, 8b of the third group frame 8. Therefore, even if the first lens unit L1 and the second lens unit L2 are inclined with respect to the optical axis, their inclination directions are the same as those of the image blur correction lens unit L3, so that a predetermined optical performance is ensured. Can be.
[0054]
At the time of actual photographing, the second-group lens drive actuator 6 and the fourth-group lens drive actuator 12 respectively perform a zooming operation and a correction of an image plane variation caused by the zooming and a focusing operation. At the time of zooming, shooting is performed in the state shown in FIG. 16 at the wide-angle end, and at the telephoto end, the second lens unit L2 is moved in the −Z direction (the end on the side of the image sensor 14). Photographing is performed in the state shown in FIG. Therefore, it is possible to shoot at an arbitrary position from the wide-angle end to the telephoto end.
[0055]
Next, an operation when shifting from the state at the time of photographing shown in FIG. 16 to the state at the time of non-photographing shown in FIG. 14 via the state shown in FIG.
[0056]
When the power switch or the like of the camera is turned off from the state at the time of photographing (wide-angle end) in FIG. 16, photographing ends, and the second group moving frame 5 is first moved to the image sensor 14 by the second group lens drive actuator 6. Thus, the state shown in FIG. 15 is obtained. Next, the first lens drive actuator 22 is rotated, and the drive gear 19 is rotated via the reduction gear unit 23 in the opposite direction. When the drive gear 19 rotates, the drive frame 15 meshed with the drive gear 19 rotates about the optical axis, and at the same time, moves toward the image sensor 14 by the cam grooves 18a, 18b, and 18c, whereby 1 The group moving frame 3 also moves. When the rotation of the drive frame 15 is detected by the origin detection sensor 27, the rotation of the first-group lens drive actuator 22 is stopped after the first-group moving frame 3 moves to a predetermined position. At this stop position, the cam pins 16a, 16b, 16c have reached a portion 19a substantially parallel to the circumferential direction of the cam frame 17 in the developed view of the cam groove in FIG. As a result, the state is shifted to the state shown in FIG. 14, and the retracted state becomes shorter by the length C than the state at the time of photographing.
[0057]
Here, the collapsing operation for changing the length of the collapsible lens barrel 1 in the optical axis direction uses the first lens drive actuator 22 for driving the first lens L1, and the zooming operation uses the second lens drive actuator 6 alone. Used in. Therefore, since the zooming operation in the actual photographing is performed in a state where the first lens unit L1 is extended, it is not necessary to operate the first lens drive actuator 22, and only the second lens drive actuator 6 is driven as shown in FIG. Zooming can be performed by moving the second lens unit L2 to a predetermined position between the positions shown in FIG. Therefore, when performing photographing such as performing a zooming operation, unlike the collapsible lens barrel of the conventional system shown in FIG. 17, it is necessary to perform the extension operation and the retraction operation of the lens barrel according to the zoom magnification. Absent. In the conventional collapsible lens barrel shown in FIG. 17, during the zooming operation, one drive actuator 69 is rotated, and the cam barrel 61 is rotated via the reduction gear train 68 so that the movable lens frames 62 and 63 are simultaneously moved. Since it was driven, the zooming speed is slow and the driving noise is loud. The collapsible lens barrel 1 of the present invention uses a stepping motor as the second group lens driving actuator 6 and directly drives the second group moving frame 5 via a feed screw 6a attached to the stepping motor. Feeding speed is fast and operation noise is low. As described above, according to the present invention, even with a retractable lens barrel, it is possible to realize a high zoom speed and a low noise zoom sound. Therefore, the photographer can instantly change the angle of view, and can perform a usage method that is not suitable for the conventional DSC, such as following a subject or shooting a moving image.
[0058]
As described above, according to the present embodiment, a collapsible lens barrel including a cylindrical cam frame and a substantially hollow cylindrical drive frame including a cam pin, and in a collapsed state, includes a cam pin and a cam groove. The wide groove is formed in the cam groove so that the cam pin does not come in contact with the cam groove, causing inconveniences such as deformation of the cam pin and damage to the cam groove even when a compressive load is applied in the optical axis direction during assembly in the collapsed state. Does not occur.
[0059]
Further, the first group lens L1 and the second group lens L2 are configured so as to be inclined at least in the same direction with respect to the image blur correction lens L3, so that a decrease in optical performance is minimized while the lens is not used. It is possible to realize a collapsible lens barrel capable of reducing the overall length and corresponding to high magnification.
[0060]
In addition, despite being a collapsible lens barrel using a cam frame, which is complicated to assemble, the parts can be assembled and screwed and fixed from the same direction, compared to the conventional method of assembling from both directions. The number of assembling steps can be reduced and the assembling work can be simplified.
[0061]
In the present embodiment, the first-group frame 2 provided with the first-group lens L1 and the first-group moving frame 3 are separately configured. However, the first-group lens L1 and the first-group moving frame 3 are integrally configured, and a guide pole is fixed to the integrated portion. It is good.
[0062]
Note that the third group lens L3 can be moved in the direction orthogonal to the optical axis by using the image blur correction device 31, but the third group lens L3 is fixed to the third group frame 8, and the image blur correction device is mounted. It is needless to say that the same effect can be obtained even with a general lens barrel that does not.
[0063]
【The invention's effect】
As described above, according to the retractable lens barrel of the present invention, in the retracted state, even if a compressive load is applied in the optical axis direction, the engaging means does not come into contact with the cam groove, so that the engaging means is deformed. It is possible to prevent damage to the lens barrel, such as damage to the cam groove or the cam groove.
[0064]
In addition, as a collapsing actuator separate from the zooming drive actuator, a drive means is provided to extend the photographing lens group toward the object side during photographing, and to move the photographing lens group toward the image plane during non-photographing. It is not driven, so that the zoom time can be increased and the zoom noise can be reduced.
[0065]
Further, according to the collapsible lens barrel assembling method of the present invention, since all parts are assembled from the same direction, the number of assembling steps can be reduced, and the cost of the lens barrel can be reduced. .
[0066]
Further, since the fourth assembling step of fixing the fixing frame to the cam frame is performed in a state where the engaging means is moved to the wide portion of the cam groove, the compressive load in the optical axis direction is reduced at the time of the fourth assembling step. Even if it is added to the lens barrel, since the engaging means and the cam groove are not in contact with each other, inconveniences such as deformation of the engaging means and damage to the cam groove do not occur.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view of a retractable lens barrel according to an embodiment of the present invention.
FIG. 2 is an exploded perspective view illustrating a guide pole support of the collapsible lens barrel according to the embodiment of the present invention.
FIG. 3A is a diagram showing a lens inclination in an ideal collapsible lens barrel, and FIG. 3B is a diagram showing a lens inclination in a conventional collapsible lens barrel. FIG. 3C is a diagram showing the inclination of the lens in the retractable lens barrel according to one embodiment of the present invention.
FIG. 4 is a development view of a cam groove in the collapsible lens barrel according to the embodiment of the present invention.
FIG. 5A is a partial cross-sectional view in a direction parallel to the optical axis, showing an engagement state between a cam pin and a cam groove in the collapsible lens barrel according to one embodiment of the present invention. . FIG. 5B is a partial sectional view in a direction parallel to the optical axis, showing an engagement state between a cam pin and a cam groove in a wide portion of the cam groove in the retractable lens barrel according to one embodiment of the present invention. FIG.
FIG. 6 is an exploded perspective view of a cam frame in the retractable lens barrel according to one embodiment of the present invention.
FIG. 7 is a flowchart illustrating a method of assembling the retractable lens barrel according to the embodiment of the present invention.
FIG. 8 is a perspective view illustrating a first assembling step of the method of assembling the retractable lens barrel according to the embodiment of the present invention.
FIG. 9 is a perspective view illustrating a second assembling step of the method of assembling the retractable lens barrel according to one embodiment of the present invention.
FIG. 10 is a perspective view illustrating a third assembling step of the method of assembling the retractable lens barrel according to one embodiment of the present invention.
FIG. 11 is a perspective view illustrating a fourth assembling step of the method of assembling the retractable lens barrel according to one embodiment of the present invention.
FIG. 12 is a cross-sectional view illustrating an engagement state between a cam pin and a cam groove in a fourth assembling step in the retractable lens barrel according to one embodiment of the present invention.
FIG. 13 is a perspective view illustrating a method of fixing a flexible print cable in the method of assembling the retractable lens barrel according to one embodiment of the present invention.
FIG. 14 is a cross-sectional view of the collapsible lens barrel according to an embodiment of the present invention when it is collapsed.
FIG. 15 is a sectional view of the retractable lens barrel according to the embodiment of the present invention when the telephoto end is used.
FIG. 16 is a cross-sectional view of the retractable lens barrel according to the embodiment of the present invention when the wide-angle end is used.
FIG. 17 is an exploded perspective view of a conventional collapsible lens barrel.
[Explanation of symbols]
L1 1st lens L2 2nd lens (zoom lens)
L3 Image blur correction lens group (3rd lens group)
L4 4 group lens (focusing lens)
REFERENCE SIGNS LIST 1 retractable lens barrel 2 1 group frame 3 1 group moving frame 4 a, 4 b guide pole 5 2 group moving frame 6 2 group lens driving actuator 8 3 group frame 8 a, 8 b guide pole support 9 4 group moving frame 10 master flange 12 Fourth lens drive actuator 14 Image sensor (CCD)
15 Drive Frame 16a, 16b, 16c Cam Pin 17 Cam Frame 17a Drive Gear Attachment 17b Drive Actuator Attachment 17c Origin Detection Sensor Attachment 17d Drive Gear Bearings 18a, 18b, 18c Cam Groove 19 Drive Gear 21 Drive Gear Unit 22 First-group lens drive actuator 24 Shutter unit 25 Second-group lens origin detection sensor 26 Fourth-group lens origin detection sensor 27 First-group lens origin detection sensor 31 Image blur correction device 35 Mounting screw 36 Electric board (flexible printed circuit board) )
38 Flexible Printed Cable

Claims (2)

A holding frame for holding the taking lens group,
A cylindrical cam frame formed with a plurality of cam grooves,
An engagement means for engaging with the cam groove is provided, and a substantially hollow cylindrical drive interlocked with the holding frame in the optical axis direction by rotating relative to the cam frame about the optical axis as a rotation center. A frame,
Driving means for moving the photographing lens group toward the object side during photographing, and moving the photographing lens group toward the image plane side when not photographing,
A wide portion having an increased width in the optical axis direction is formed in the cam groove so that the engaging means does not come into contact with the cam groove in a state where the photographing lens group is moved to the most image plane side. A collapsible lens barrel. A collapsible lens barrel assembling method according to claim 1,
A first assembly step of assembling the holding frame and the drive frame;
A second assembly step of assembling the drive frame and the cam frame by engaging the engagement means with the cam groove;
A third assembling step of moving the engagement means of the drive frame to the wide portion of the cam groove;
A fourth assembling step of fixing a fixed frame on which the driving unit is held to the cam frame,
A method of assembling a collapsible lens barrel, wherein all of the first to fourth assembling steps are performed from the same direction.

Images