JP3980125B2 - Camera lens drive mechanism - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a lens driving mechanism of a camera that drives a plurality of mechanisms such as a zoom lens, a zoom finder, and a zoom strobe through an identical rotary lens barrel.
[0002]
[Prior art and its problems]
Zoom compact cameras equipped with a zoom lens and a zoom finder or a zoom strobe are known. For zooming by rotation of the cam ring, a gear is formed on the cam ring, and the zooming gear (drive pinion) on the motor side and the finder drive gear (driven pinion) of the zoom finder drive mechanism are engaged with the gear. It was. The cam ring gear is shared by the zooming gear and the film underdrive gear, or formed separately by the same module. In any case, conventionally, these gears are formed by a common module.
[0003]
Since a large torque is required for zooming, the gear that meshes with the pinion of the zoom motor is a relatively large module. Therefore, the gear that meshes with the drive pinion of the zoom finder drive mechanism is also formed of the same module. Therefore, the module on the zoom finder drive mechanism side becomes larger than necessary, the diameter of the finder drive pinion is large, and the center position is away from the optical axis.
[0004]
5 and 6 show a main part of a conventional camera including a zoom lens and a zoom finder. FIG. 5 is a cross-sectional view showing the upper half of the main part of the zoom lens taken along the optical axis, and FIG. 6 is a schematic front view showing the configuration of the cam ring and pinion. The conventional camera is provided with a cam ring 15 ′ having a zooming pinion 21 ′ and a finder driving pinion 27 ′ having the same module and a gear 17 ′ with which the pinions 21 ′ and 27 ′ mesh. The zooming gear 21 ′ and the finder driving gear 27 ′ are arranged on the opposite sides of the optical axis, but the distance from the optical axis of the zooming gear 21 ′ and the finder driving gear 27 ′, the teeth In order to facilitate the comparison of the position of the tip circle and the like, FIG. 5 shows the positions of the gears 21 ′ and 27 ′ in the circumferential direction being shifted and the center being positioned on the paper surface.
[0005]
As is apparent from these drawings, in the conventional camera, the pinions 27 ′ and 21 ′ are located within the same radius from the optical axis O. That is, the modules of the pinion 21 ', 27' and the gear 17 'of the cam ring 15' in which these mesh with each other are set to be the same. Since this module was set based on conditions such as torque (maximum load) in order to obtain sufficient strength, the finder drive pinion 27 'and other gears were larger than necessary.
[0006]
OBJECT OF THE INVENTION
The present invention has been made in view of the problems of the above-described conventional camera lens driving mechanism, and an object thereof is to provide a camera lens driving mechanism capable of reducing the size of the camera.
[0007]
SUMMARY OF THE INVENTION
The present invention that achieves this object is a lens driving mechanism that interlocks and drives a zoom lens and a zoom finder by rotation of a lens barrel, a zooming gear for transmitting the rotation of the zoom motor, and a finder optical system The finder driving gear for driving the finder driving gear is set to be smaller than the zooming gear module, and the lens is arranged on a common plane orthogonal to the lens optical axis of the rotating lens barrel. It is characterized by being formed in a region that is substantially symmetric with respect to the optical axis .
According to a fifth aspect of the present invention, there is provided a lens driving mechanism for driving the zoom lens and the zoom strobe in conjunction with each other by the rotation of the rotating lens barrel, a zooming gear for transmitting the rotation of the zoom motor, and the irradiation of the zoom strobe. The driving gear for driving the variable angle mechanism is set so that the driving gear module is smaller than the zooming gear module, and the lens is on a common plane orthogonal to the lens optical axis of the rotating barrel. It is characterized in that it is formed in a region that is substantially symmetrical with respect to the optical axis.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described below with reference to the drawings. FIG. 1 is a front view showing a main part of a zoom compact camera equipped with a retractable two-group zoom lens to which the present invention is applied. A zoom lens 13 is mounted on the front of the camera body 11 at a position slightly lower right than the center. Only the cam ring 15 is shown in the figure. A photometric element 12a, a self-timer display element 12b, light emitting / receiving elements 12c and 12d for distance measurement, a zoom finder 29, and a zoom strobe 12e are arranged on the upper front of the camera body 11 from the left side.
[0009]
On the outer periphery of the cam ring 15, a zooming gear 17 that meshes with a zooming pinion 21 and a finder driving gear 19 that meshes with a finder driving pinion 27 are formed in a circumferential direction at a position sandwiching the optical axis O.
[0010]
The rotation of a zooming motor 23 mounted in the camera body as a drive source is transmitted to the zooming pinion 21 via a reduction gear train 25. The cam ring 15 is rotationally driven by the rotation of the zooming pinion 21. In the zoom lens 13, the lens barrel protrudes from the retracted position to the shootable position, zooms in the shooting area between the shootable position and the most protruded position, and is pulled from the shootable area to the retracted position.
[0011]
Further, the finder driving pinion 27 is rotated by the rotation of the cam ring 15. The finder drive pinion 27 drives the zoom mechanism of the zoom finder 29, and the finder field magnification changes according to the focal length (view angle) of the zoom lens 13.
[0012]
The configuration of the gears 17 and 19 and the pinions 21 and 27 of the cam ring 15 will be described in more detail with reference to FIG. FIG. 2 is an enlarged front view showing the configuration of the cam ring and the pinion, where (A) is an enlarged view of the vicinity of the zooming pinion 21 and (B) is an enlarged view of the vicinity of the finder driving pinion 27. .
[0013]
Assuming that the module of the zooming pinion 21 and the zooming gear 17 is M1, and the module of the finder driving pinion 27 and the finder driving gear 19 is M2, in the illustrated embodiment, these modules M1 and M2 satisfy M1> M2. Is set to Therefore, the pitch circle radius of the finder driving pinion 27 and the finder driving gear 19 is smaller than the pitch circle radius of the zooming pinion 21 and the zooming gear 17.
[0014]
Further, if the distance from the rotation center (optical axis O) of the zooming pinion cam ring 15 to the axis of the zooming pinion 21 is r1, and the distance from the axis of the finder driving pinion 27 is r2, then r2 <r1. . The maximum radius R2 from the optical axis O to the tooth tip circle of the zooming pinion 21 is smaller than the maximum radius R1 from the optical axis O to the tooth tip circle of the finder driving pinion 27.
According to this embodiment, the space for housing the zooming pinion 27 can be small, and the size of the camera can be reduced.
[0015]
In FIG. 3, the cam ring 15 is shown expanded. A multi-helicoid 18 having a predetermined lead is formed on the outer peripheral surface of the cam ring 15. The gears 17 and 19 are formed by removing the crest of the helicoid 18 and forming teeth extending in parallel with the optical axis O along the helicoid 18 between the crests. The helicoid 18 is formed so as not to interfere with the peaks and the gears 17 and 19 and the pinions 21 and 27.
[0016]
FIG. 4 is a cross-sectional view showing the upper half of the configuration of the lens unit of the zoom lens shutter type camera to which the present invention is applied, vertically cut along the optical axis O. This lens shutter type camera is a two-group zoom lens including a front group lens L1 and a rear group lens L2. Note that the zooming gear 21 and the finder driving gear 27 are shown with their circumferential positions shifted and their centers positioned on the paper surface.
[0017]
An adjustment ring 33 is fitted and fixed in a cylindrical portion of the housing 31 which is a fixing portion of the camera body 11 so as to be rotatable about the optical axis O and not moved in the optical axis direction. Yes. A multiple helicoid 33a is formed on the inner peripheral surface of the adjustment ring 33, and the multiple helicoid 18 formed on the outer peripheral surface of the cam ring 15 is screwed into the multiple helicoid 33a. That is, when the cam ring 15 is rotationally driven by the zooming motor 23, the cam ring 15 moves forward and backward while rotating according to the leads of the multiple helicoids 18 and 33a.
[0018]
A multiple helicoid 20 is formed on the inner peripheral surface of the cam ring 15, and a multiple helicoid 35 a formed on the outer peripheral surface of the movable lens barrel 35 is screwed to the multiple helicoid 20. A donut-shaped shutter unit 39 is mounted in the movable lens barrel 35 via a shutter mounting member 37, and a front group lens L1 is helicoidally coupled to the inner periphery of the shutter unit 39 via a front group lens holding frame. ing. The front lens group L1 is rotationally driven by an AF ring 41, and moves forward and backward in accordance with a helicoid lead to adjust the focus.
[0019]
A rectilinear guide plate 47 fixed to the housing 31 extends in the movable lens barrel 35. The rectilinear guide plate 47 is guided so that the rectilinear guide ring 43 and the rectilinear guide presser 45 move straight without rotating. The shutter mounting member 37 integrated with the movable lens barrel 35 is linearly guided by three arms provided on the linear guide ring 43.
[0020]
A rear group lens L2 held by a rear group lens holding frame 49 is disposed behind the shutter unit 39. Although not shown, the rear group lens holding frame 49 is guided by the shutter mounting member 37 through a plurality of arms extending forward so as to be able to move straight forward. Further, a plurality of cam pins 51 project from the outer periphery of the rear lens group holding frame 49 at predetermined intervals, and these cam pins 51 are fitted in cam grooves formed in the cam ring 15.
[0021]
In the zoom lens 13 having this configuration, when the zooming pinion 21 is driven to rotate by the zoom motor 23, the cam ring 15 moves forward and backward while rotating, and the shutter mounting member 37 is integrated with the movable lens barrel 35 so as to be linearly guided. It is guided by the ring 43 and moves forward and backward without rotating. On the other hand, the rear lens group L2 is constrained by the cam groove of the cam ring 15 and the linear guide groove of the linear guide plate 47 and moves forward and backward without rotating, and zooms by changing the distance from the front lens group L1.
[0022]
As apparent from FIG. 4, the finder driving pinion 27 is closer to the optical axis O than the zooming pinion 21 and has a smaller diameter, that is, the finder driving pinion 27 is the zooming pinion 21. It can be seen that it is within a smaller space.
[0023]
FIG. 5 is a cross-sectional view similar to FIG. 4 of a conventional compact camera having a zooming pinion 21 'and a finder driving pinion 27' having the same module. As is clear from this figure, the finder driving pinion 27 'of the conventional camera has the same module as the zooming pinion 21', so the distance from the optical axis O to the center and the diameter of the tooth tip circle are the same. Required the same containment space.
[0024]
On the other hand, in the embodiment of the present invention shown in FIG. 4, the finder driving pinion 27 has a smaller diameter than the zooming pinion 21 and fits in a small space, so that the space for accommodating the finder driving pinion 27 is accommodated. Is smaller and lighter, and the camera can be made smaller and lighter.
[0025]
The above illustrated embodiment is an embodiment applied to a retractable two-group zoom lens. However, it goes without saying that the present invention is not limited to this embodiment, and also to a three-group zoom lens and a single focus lens. Applicable.
In the illustrated embodiment, the lens driving mechanism for driving the zoom finder 29 in conjunction with the zooming due to the rotation of the cam ring 15 during zooming is shown, but the mechanism for driving the irradiation angle variable mechanism of the zoom strobe 12e is also shown. Applicable.
[0026]
【The invention's effect】
As is apparent from the above description, the present invention relates to a gear formed on the rotating lens barrel of the lens for transmitting the driving force of the driving source to the rotating lens barrel, and a gear for transmitting the rotation of the rotating lens barrel to another mechanism. Since the modules are made different according to the torque of each gear, the corresponding pinion modules that mesh with these gears are also different, obtaining the required strength and eliminating unnecessary space, making the camera smaller and lighter Can be achieved.
[Brief description of the drawings]
FIG. 1 is a front view showing a main part of an embodiment of a zoom compact camera including a retractable two-group zoom lens to which the present invention is applied.
2A and 2B are enlarged views showing a cam ring and a pinion of the zoom compact camera, wherein FIG. 2A is an enlarged view near a zooming pinion, and FIG. 2B is an enlarged view near a finder driving pinion; It is.
FIG. 3 is an unfolded view of a cam ring.
FIG. 4 is a cross-sectional view showing the upper half of the configuration of the lens unit of the zoom compact camera, vertically cut along the optical axis of the zoom lens.
FIG. 5 is a cross-sectional view showing the upper half of a configuration of a lens unit of a conventional zoom compact camera, which is vertically cut along the optical axis of the zoom lens.
FIG. 6 is a front view showing a configuration of a cam ring and a pinion of a conventional zoom compact camera.
[Explanation of symbols]
11 Camera body 13 Zoom lens 15 Cam ring 17 Zooming gear 19 Finder gear 21 Zooming pinion 23 Zooming motor 27 Finder driving pinion 29 Zoom finder

Claims (5)

A lens driving mechanism that interlocks and drives the zoom lens and the zoom finder by rotating the lens barrel;
The zooming gear for transmitting the rotation of the zoom motor and the finder driving gear for driving the finder optical system are set so that the finder driving gear module is smaller than the zooming gear module, and the rotation is performed. A lens driving mechanism for a camera, wherein the lens driving mechanism is formed in a region that is substantially symmetric with respect to the optical axis of the lens on a common plane orthogonal to the optical axis of the lens of the lens barrel. At a position opposite to each other across the optical axis of the lens, the zooming gear is engaged with a zooming pinion driven by a zoom motor, and the finder driving gear is engaged with a finder driving pinion for zooming the finder. The lens driving mechanism for a camera according to claim 1 . The rotating barrel, while rotating forward and backward movement to the camera lens drive mechanism according to claim 1 or 2 is a cam ring for zooming. In the rotating lens barrel, a multiple helicoid formed on an outer peripheral surface meshes with a multiple helicoid formed on an inner peripheral surface of a fixed lens barrel of the camera, and the zooming gear and the finder driving gear are screw threads of the multiple helicoid. The lens driving mechanism for a camera according to claim 1 , wherein the lens driving mechanism is formed between the two. A lens driving mechanism that interlocks and drives the zoom lens and the zoom strobe by rotation of the lens barrel;
A zooming gear for transmitting the rotation of the zoom motor and a driving gear for driving the irradiation angle variable mechanism of the zoom strobe are set smaller than the zooming gear module, A lens driving mechanism for a camera, wherein the lens driving mechanism is formed in a region that is substantially symmetrical with respect to the optical axis of the lens on a common plane orthogonal to the optical axis of the lens of the rotating lens barrel.

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