JPH1144835A - Lens driving mechanism for camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens driving mechanism for a camera capable of realizing the miniaturization of the camera. SOLUTION: In this lens driving mechanism interlocking and driving a zoom lens 13 and a zoom finder 29 by the rotation of a cam ring 15, the modules of a zooming gear 17 for transmitting the rotation of a zoom motor 23 and a finder driving gear 19 for driving the variable power mechanism of the finder 29, which are formed on the cam ring 15, are set so that the module of the gear 19 may be smaller than that of the gear 17.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens drive mechanism for a camera that drives a plurality of mechanisms, such as a zoom lens and a zoom finder or a zoom strobe, interlockingly via the same rotary lens barrel.

[0002]

2. Description of the Related Art A zoom compact camera provided with a zoom lens and a zoom finder or a zoom strobe is known. In the case of zooming by rotating the cam ring, a gear is formed on the cam ring,
A gear for zooming (drive pinion) on the motor side and a finder drive gear (driven pinion) of the zoom finder drive mechanism are meshed with the gear. The gear of the cam ring is commonly used for the zooming gear and the film under drive gear, or formed separately in the same module. In any case, conventionally, these gears are formed by a common module.

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 unnecessarily large,
The diameter of the finder drive pinion was large, and the center position was far from the optical axis.

FIGS. 5 and 6 show a main part of a conventional camera having a zoom lens and a zoom finder. FIG. 5 is a cross-sectional view showing the upper half of a main part of the zoom lens taken along the optical axis, and FIG. 6 is a schematic front view showing the configuration of a cam ring and a pinion. The conventional camera has a zooming pinion 21 ', a finder driving pinion 27', and a pinion 2 having the same module.
Cam ring 1 having gear 17 'meshing with 1', 27 '
5 '. The zooming gear 21 'and the finder driving gear 27' are arranged on opposite sides of the optical axis. However, the distance between the zooming gear 21 'and the finder driving gear 27' from the optical axis and the teeth In order to facilitate comparison of the position of the tip circle, etc., FIG.
In the figure, the center is located on the paper surface with the circumferential positions shifted by 1 'and 27'.

As apparent from these figures, in the conventional camera, the pinions 27 'and 21' are located within the same radius from the optical axis O. That is, the pinions 21 ', 27',
The module of the gear 17 'of the cam ring 15' in which these mesh with each other is set identically. This module is set based on conditions such as torque (maximum load) in order to obtain sufficient strength.
7 ', other gears were larger than necessary.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a camera lens driving mechanism capable of reducing the size of the camera in view of the above-mentioned problem of the conventional camera lens driving mechanism. .

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is a lens driving mechanism for driving a plurality of mechanisms by rotating a rotary barrel of a lens, wherein a driving force of a drive source formed on the rotary barrel is reduced. It is characterized in that the gears for transmitting the rotation of the rotary barrel to other mechanisms are different from each other in accordance with the torque of each gear. The present invention provides a lens driving mechanism that includes a zoom lens and a zoom finder and that drives the zoom lens and the zoom finder in conjunction with the rotation of a rotary lens barrel, wherein the zoom lens includes a zooming gear for transmitting rotation of a zoom motor to the rotary lens barrel. And a finder driving gear for driving a finder optical system, wherein the finder driving gear module is formed smaller than the zooming gear module.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 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 provided with a retractable two-group zoom lens to which the present invention is applied. On the front of the camera body 11, a zoom lens 13 is mounted at a position slightly lower right from the center. In the figure, only the cam ring 15 is shown. On the front upper portion of the camera body 11, a photometric element 12a, a self-timer display element 12b, a light emitting / receiving element 12c for distance measurement,
2d, zoom finder 29 and zoom strobe 12
e is arranged.

On the outer periphery of the cam ring 15, a zooming gear 17 in which a zooming pinion 21 meshes and a finder gear 1 in which a finder driving pinion 27 meshes.
Reference numeral 9 is formed in the circumferential direction at a position sandwiching the optical axis O.

The rotation of a zooming motor 23 as a drive source mounted in the camera body is transmitted to a zooming pinion 21 via a reduction gear train 25.
Then, the cam ring 15 is rotated by the rotation of the zooming pinion 21. And the zoom lens 13
The lens barrel projects from the collapsed position to the photographable position, zooms in the photographing area between the photographable position and the most protruding position, and is retracted from the photographable area to the collapsed position.

The rotation of the cam ring 15 rotates the pinion 27 for driving the finder. The zooming mechanism of the zoom finder 29 is driven by the finder driving pinion 27, and the finder field magnification is reduced by the zoom lens 1.
It changes according to the focal length (angle of view) of No. 3.

The configuration of the gears 17, 19 and the pinions 21, 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, and FIG.
1B is an enlarged view of the vicinity of the finder driving pinion 27. FIG.

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 are M1> M2 is set. 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.

If the distance from the center of rotation (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 addendum circle of the zooming pinion 21 is defined by the distance from the optical axis O to the finder driving pinion 27.
Is smaller than the maximum radius R1 up to the addendum circle. According to this embodiment, the space for accommodating the zooming pinion 27 is small, and the camera can be downsized.

FIG. 3 shows the cam ring 15 in a developed state. Multiple helicoids 18 having a predetermined lead are formed on the outer peripheral surface of the cam ring 15. The gears 17 and 19 are formed by removing teeth of the helicoid 18 and forming teeth extending parallel to the optical axis O along the helicoid 18 between the peaks.
Helicoid 18 peaks and gears 17, 19, pinion 2
1 and 27 are formed so as not to interfere with each other.

FIG. 4 is a cross-sectional view showing an upper half of a lens section of a zoom lens shutter type camera to which the present invention is applied, which is vertically cut along an optical axis O. This lens shutter camera is a two-unit zoom lens including a front lens unit L1 and a rear lens unit L2. Note that the zooming gear 2
1 and the finder driving gear 27 are shown with their centers shifted on the paper surface with their circumferential positions shifted.

An adjusting ring 33 is fitted into the cylindrical portion of the housing 31 which is a fixed portion of the camera body 11 so as to be rotatable about the optical axis O and not to move in the optical axis direction. Fixed. Multiple helicoids 33a are formed on the inner peripheral surface of the adjustment ring 33.
A multiple helicoid 18 formed on the outer peripheral surface of the cam ring 15 is screwed to 3a. That is, when the cam ring 15 is rotationally driven by the zooming motor 23, it moves forward and backward while rotating according to the leads of the multiple helicoids 18, 33a.

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 formed on the multiple helicoid 20.
Is screwed. A donut-shaped shutter unit 39 is mounted in the movable lens barrel 35 via a shutter mounting member 37, and a front lens group L1 is helicoidally coupled to the inner periphery of the shutter unit 39 via a front lens holding frame. ing. The front group lens L1 is driven to rotate by the AF ring 41, and moves forward and backward in accordance with the lead of the helicoid to adjust the focus.

A linear guide plate 47 fixed to the housing 31 extends into the movable lens barrel 35. The straight guide ring 47 and the straight guide retainer 45 are guided by the straight guide plate 47 so as to move straight without rotating. Then, a shutter mounting member 37 integrated with the movable lens barrel 35
Are guided straight by three arms provided on the straight guide ring 43.

Behind the shutter unit 39, a rear group lens L2 holding a rear group lens holding frame 49 is arranged. Although not shown, the rear group lens holding frame 49 is guided by the shutter mounting member 37 via a plurality of arms extending forward so as to be able to move straight. Further, a plurality of cam pins 51 project from the outer periphery of the rear lens holding frame 49 at predetermined intervals, and the cam pins 51 are fitted into cam grooves formed in the cam ring 15.

When the zooming pinion 21 is rotationally driven by the zoom motor 23, the zoom lens 13 having this configuration moves forward and backward while the cam ring 15 rotates.
The shutter mounting member 37 is guided by the rectilinear guide ring 43 integrally with the movable lens barrel 35 to move forward and backward without rotating. On the other hand, the rear group lens L2 is restricted by the cam groove of the cam ring 15 and the rectilinear guide groove of the rectilinear guide plate 47 and moves forward and backward without rotating, and performs zooming while changing the distance from the front lens group L1.

Here, as is apparent from FIG. 4, the pinion 27 for driving the finder is the pinion 21 for zooming.
Closer to the optical axis O and smaller in diameter, that is,
It can be seen that the finder drive pinion 27 is located in a smaller space than the zooming pinion 21.

FIG. 5 is a cross-sectional view similar to FIG. 4 of a conventional compact camera provided with a zooming pinion 21 'and a finder driving pinion 27' having the same module. As is clear from this figure, since the finder driving pinion 27 'of the conventional camera has the same module as the zooming pinion 21', the distance from the optical axis O to the center and the tip circle diameter are the same. Needed the same accommodation space.

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. The space for housing is small and lightweight, and the camera can be reduced in size and weight.

Although the illustrated embodiment described above is an embodiment applied to a retractable two-unit zoom lens, it goes without saying that the present invention is not limited to this embodiment. Also applicable to lenses. In the illustrated embodiment, the lens drive mechanism that drives the zoom finder 29 in conjunction with zooming by rotating the cam ring 15 during zooming is shown. However, a mechanism that drives the irradiation angle variable mechanism of the zoom strobe 12e may be used. Applicable.

[0026]

As is clear from the above description, the present invention
The gear module that transmits the driving force of the drive source to the rotary barrel and the gear that transmits the rotation of the rotary barrel to other mechanisms formed on the rotary barrel of the lens are made different according to the torque of each gear. Therefore, the corresponding pinion modules that mesh with these gears are also different, so that the required strength can be obtained, and unnecessary space is not required, and the camera can be reduced in size and weight.

[Brief description of the drawings]

FIG. 1 is a front view showing a main part of an embodiment of a zoom compact camera equipped with a retractable two-unit zoom lens to which the present invention is applied.

2A and 2B are enlarged views of 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 a view showing a cam ring in a developed state.

FIG. 4 is a cross-sectional view showing the upper half of the configuration of the lens unit of the zoom compact camera, which is taken along the optical axis of the zoom lens.

FIG. 5 is a cross-sectional view showing an upper half of a configuration of a lens unit of a conventional zoom compact camera, which is vertically cut along an 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]

 Reference Signs List 11 camera body 13 zoom lens 15 cam ring 17 zooming gear 19 finder gear 21 zooming pinion 23 zooming motor 27 finder drive pinion 29 zoom finder

Claims (5)

[Claims] 1. A lens driving mechanism for driving a plurality of mechanisms by rotation of a rotating barrel of a lens, a gear formed on the rotating barrel and transmitting a driving force of a drive source to the rotating barrel, and A lens driving mechanism for a camera, wherein a module of a gear for transmitting the rotation of the rotary barrel to another mechanism is made different depending on the torque of each gear. 2. A lens drive mechanism for driving a zoom lens and a zoom finder in conjunction with rotation of a rotary barrel of a lens, wherein the rotary barrel includes a zooming gear for transmitting rotation of a zoom motor, and a finder. A finder driving gear for driving an optical system, wherein the finder driving gear module is formed smaller than the zooming gear module. 3. The camera according to claim 2, wherein a zooming pinion driven by a zoom motor meshes with the zooming gear, and a finder driving pinion meshes the finder with the finder driving gear. Lens drive mechanism. 4. The lens drive mechanism for a camera according to claim 2, wherein the rotating mirror is a cam ring that moves forward and backward while rotating to perform zooming. 5. The rotating lens barrel, wherein multiple helicoids formed on the outer peripheral surface mesh with multiple helicoids formed on the inner peripheral surface of the fixed lens barrel of the camera, and the zooming gear and the finder driving gear are The lens driving mechanism of a camera according to any one of claims 2 to 4, wherein the lens driving mechanism is formed between threads of the multiple helicoid.