JPH07128568A - Lens driving device - Google Patents

Abstract

PURPOSE:To provide a lens driving device which can stop a cam corresponding to the position of a lens group at the prescribed stage with simple control in any conditions. CONSTITUTION:This device is provided with an AF cam 10 which is abutted to a cam follower 6g of a movable frame 6 linked with a mirror frame in which the photographic lens group is attached and has plural step parts corresponding to different plural positions in the direction of the optical axis of a photographic lens group, and a driving means including a control means by a photo-interrupter and the like which decides a position in the direction of the optical axis of the mirror frame by moving the AF cam and selecting step parts in the AF cam 10 to which the movable frame 6 is abutted, and the device is formed so that width along the direction of movement of the AF cam 10 in plural step parts is widened as transferring from step parts to which the movable frame 6 of the cam follower 6g in the initial condition of movement of the AF cam to step parts to which the cam follower 6g is abutted in the final condition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens drive device, and more particularly to a drive control device for a photographing lens in a camera or the like.

[0002]

2. Description of the Related Art Conventionally, various means have been known as an autofocus system for a camera. For example, a photographing lens is moved in the optical axis direction in accordance with distance measurement information obtained by using a distance measurement device, and a combination is performed. There are known technical means for bringing the focus position.

As an example of this technical means, Japanese Patent Application Laid-Open No. 1-1
Japanese Patent No. 64931 discloses a stepped cam having a plurality of steps having a constant width, which determines the position of a taking lens, a driving means for rotating the stepped cam, and a microswitch for initializing the stepped cam. And the like, and means for controlling the lens barrel to be positioned on a predetermined step of the stepped cam by rotating the stepped cam from the initial position for a predetermined time according to the object distance. There is disclosed a photographing lens driving device including:

The above-mentioned photographing lens driving device is a photographing lens driving device having a helicoid structure in which the photographing lens moves in the optical axis direction by the rotation of the lens barrel,
The device can be made smaller than a photographing lens driving device that rotates a cam that determines the position of the lens barrel in the optical axis direction and moves the photographing lens based on the output of the focus detection means. Since the control means for arranging at a predetermined position can also be realized with a simple configuration, there are advantages that the manufacturing cost can be reduced, the degree of freedom in design can be improved, and the like.

FIG. 12 is a diagram showing the relationship between the motor energization time and the cam movement amount in the above-mentioned conventional photographing lens driving device. In FIG. 12, the horizontal axis represents the time during which the motor is energized, and the vertical axis represents the cam movement amount.

As is clear from the figure, even if the motor is energized for the same time, the cam movement amount greatly varies depending on the conditions (voltage, temperature).

Here, 0- (2/3) π [ra of the cam
d] in the first step, (2/3) π to (4/3) π in the second step,
Consider a stepped cam in which (4/3) π to 2π is the third step. When the motor is energized for a predetermined time, for example, the energization time is 0 to 70 ms for the first stage cam,
In the case of the second stage cam, if the same energization time is set to 115 to 140 ms, it is possible to stop at the target cam stage regardless of the conditions.

[0008]

However, with the above technical means, it is difficult to set the energization time that can be stopped under all conditions when the cam stage is the third stage described above.

Also in the technical means disclosed in the above-mentioned Japanese Patent Laid-Open No. 1-164931, it is assumed that the motor is susceptible to fluctuations due to temperature and voltage, and by forming each step on the cam with a constant width, the photographing is performed. Although an attempt has been made to accurately control the position of the lens, if the width of each step is constant, it is naturally necessary to set each step to the width with the largest variation. As described above, if the motor energization time is short, the variation is small,
In the above-mentioned conventional example, there has been a problem that a cam stage longer than necessary must be provided, which has been a factor of increasing the size of the apparatus.

As described above, according to the conventional technique, it is difficult to stop the cam at the target stage depending on the conditions such as voltage and temperature.

The present invention has been made in view of the above problems, and solves the above problems and, under any conditions,
An object of the present invention is to provide a lens driving device capable of stopping a cam corresponding to the position of a lens group at a predetermined stage with simple control.

[0012]

In order to achieve the above object, the lens driving device according to the present invention is a lens driving device for moving at least one lens group in an optical system in the optical axis direction. Cam means having a plurality of step portions that abut the lens group and correspond to a plurality of different positions of the lens group in the optical axis direction, and a step in the cam means that moves the cam means and that abuts the lens group. A drive means for determining the position of the lens group in the optical axis direction by selecting a portion, and the width of the plurality of step portions along the moving direction of the cam means is
It is characterized in that it is formed so as to become wider as the transition from the step portion with which the lens group is in contact in the initial state of the movement of the cam means to the step portion with which the lens group is in contact in the final state.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an exploded perspective view showing a lens driving device according to an embodiment of the present invention.

This lens driving device includes a lens frame 1 in which known photographing lenses 2 to 4 are provided, a movable frame 6 which holds the lens frame 1 rotatably and moves back and forth in the optical axis direction. The camera body 7 holds the moving frame 6.

The lens frame 1 is composed of a large-diameter cylindrical portion 1b and a small-diameter cylindrical portion 1c. On the outer peripheral rear surface side of the large-diameter cylindrical portion 1b, a slope cam formed on a moving frame 6 to be described later. 6f
Is formed so as to project rearward, and comes into contact with the slope cam 6f when the small-diameter cylindrical portion 1c is embedded in the moving frame 6 and assembled.

The moving frame 6 has a substantially cylindrical shape having an inward flange, and three sloped cams 6f are formed at equal intervals on the front portion of the outer peripheral wall 6a. The slope cam 6f is
As described above, when the lens frame 1 is assembled to the movable frame 6, it can come into contact with the cam follower 1a of the lens frame 1. As a result, the lens frame 1 rotates with respect to the moving frame 6 and moves back and forth in the optical axis direction.

Further, a protruding piece 6b is provided on the lower portion of the outer peripheral surface of the moving frame 6 so as to project downward, and serves as a part of a moving mechanism of the moving frame 6 in the optical axis direction. The moving mechanism will be described in detail later.

From the rear surface of the moving frame 6, as shown in FIG. 2, two shafts 6c and 6d are formed extending rearward in parallel with the optical axis.

Returning to FIG. 1, on the front surface of the camera body 7,
The shaft 6 is provided at a position facing the two shafts 6c and 6d.
Inserted portions of c and 6d are formed. The moving frame 6 is
The two shafts 6c and 6d are inserted into the insertion portion and are engaged with the camera body 7 so as to be movable in the optical axis direction. Further, the shafts 6c and 6d serve as guides when the movable frame 6 is extended from the camera body 7 in the optical axis direction.

On the front side of the camera body 7, one side of the insertion portion of the moving frame 6 is provided with a leaf spring 5 at its base end portion 5b.
Are fixed by screws 5c. The leaf spring 5 has an L-shaped free end extending from the base end 5b, and the tip 5a is formed in a curved shape.
When the moving frame 6 is inserted into the camera body 7, the tip portion 5a comes into contact with the projecting piece 6b of the moving frame 6 described above,
The projecting piece 6b is biased in a direction of pressing the cam surface of the AF cam 10 described later.

FIG. 3 is an exploded perspective view of the main part of the camera body 7 and its peripheral parts seen from the bottom side.

Two circular recesses 7a and 7b are formed in the central portion of the bottom surface of the camera body 7, and an autofocus cam (in the right direction in the drawing) of the autofocus cam ( Hereinafter, the AF cam) 10 is the concave portion 7
It is rotatably supported by a support shaft arranged in the center of the shaft.

An autofocus cam gear (hereinafter referred to as an AF cam gear) 9 that rotates integrally with the AF cam 10 is provided on the lower surface (upper surface side in FIG. 3) of the AF cam 10. Further, an autofocus gear (hereinafter referred to as AF gear) 8 is arranged from below.

Power is transmitted to the AF gear 8 from a drive source motor 27 (see FIG. 6), which will be described later, through a gear train, and the AF cam 10 rotates the AF gear 8. It is designed to rotate in conjunction with.

The cam surface of the AF cam 10 is the moving frame 6
Of the AF cam 10 by means of the leaf spring 5 engaging with the protruding piece 6b.
Is urged in the direction of pressing the cam surface.

FIG. 4 is a plan view (a) and a side view (b) showing the positional relationship between the AF cam 10 and the projecting piece 6b of the movable frame 6. As shown in FIG.

As shown in the figure, one side of the projecting piece 6b projects rearward, that is, slightly projects toward the cam surface of the AF cam 10 to form a cam follower (AF cam engaging portion) 6g. . The cam follower 6g comes into contact with the cam surface of the AF cam 10, and thereby the moving frame 6 is interlocked with the rotation of the AF cam 10 rotated by the AF gear 8.
Is guided by the shafts 6c and 6d to move in the optical axis direction. With the movement of the moving frame 6, the lens frame 1
Moves in the direction of the optical axis, and the taking lens is focused. It should be noted that when the AF cam 10 makes one rotation, the movable frame 6, that is, the lens frame 1 reciprocates once in the optical axis direction.

The AF cam 10 is composed of an initial position stage and three cam stages for setting the lens extension amount. Further, the widths of the three cams are set to be gradually wider from the first-stage cam to the second-stage cam surface and to the second-stage cam to the third-stage cam.

In the present embodiment, the number of cam stages for setting the lens extension amount is set to three stages, but the present invention is not limited to this and may be four stages or more. The position stage and the first stage of the feeding stage may be formed in the same stage, and the cam width of the third stage may be wider than that of the second stage. It should be noted that this initial position stage and feeding stage 1
An example in which the step and the step are formed in the same step will be described later.

Returning to FIG. 3, in the other concave portion 7b formed on the bottom surface of the camera body 7, an autofocus / photointerrupter gear (hereinafter referred to as AFPI gear) 1 is provided.
1 is rotatably supported on a support shaft arranged at the center of the recess 7b. The AFPI gear 11 meshes with the AF cam gear 9 at a gear ratio of 1: 1 so that one rotation of the AF cam 10, that is, one reciprocating movement of the lens frame 1 is performed by the AFPI gear 11. It corresponds to one rotation of the gear 11.

A part of the lower surface (upper surface side in FIG. 3) of the AFPI gear 11 projects in a fan shape toward the outer peripheral direction, and a light shielding piece 11a is integrally formed.

On the other hand, on one side of the bottom surface of the camera body 7, an autofocus / photointerrupter (hereinafter referred to as AFPI
12) is arranged so that the slit is on the locus of the light shielding piece 11a. The output signal from the AFPI 12 is transmitted to the CPU 23 (see FIG. 6) in the control circuit described later. Also, the AF
The PI 12 outputs an output signal of "HIGH" level to the CPU 23 when the light shielding piece 11a is arranged in the slit and shielded by the rotation of the AFPI gear 11.

As described above, the AFPI gear 11 and the A
Since the F-cam 10 makes the same rotation, the light-shielding piece 11a passes through the slit of the AFPI 12 once each time the lens frame 1 reciprocates once. In this example,
When the AF cam 10 is in the initial position (state in which the lens is retracted), the light shielding piece 11a is arranged in the slit of the AFPI 12.

The operation of the lens driving device of the present embodiment having such a configuration will be described with reference to the timing chart shown in FIG.

FIG. 5 shows an AF cam 1 that extends the lens frame 1.
6 is a time chart showing the relationship between 0 and the output pulse signal of the AFPI 12.

Usually, the AF cam 10 is arranged at the initial position. When the AF cam 10 is arranged at the initial position, as described above, the light blocking piece 11a of the AFPI gear 11 that moves in synchronization with the AF cam 10 moves the AFPI 12 to the AFPI 12.
The output of AFPI12 is "HI" because it is inside the slit.
GH "level.

At this time, the cam follower (AF cam engaging portion) 6g of the moving frame 6 selects an appropriate cam step according to the result of distance measurement according to the position shown in the figure, whereby the AF is driven by the transmitted motor. The cam 10 rotates in a predetermined direction.

When the AF cam 10 rotates in a predetermined direction from the initial position, the light blocking piece 11a of the AFPI gear 11 is moved.
Is separated from the AFPI12 slit, the AFP
I12 becomes transparent, and the output of AFPI12 is "L".
It becomes OW "level. It is possible to judge whether the lens position is in the initial position or the extended position by the output change of the AFPI 12. In the figure, t1 to t3 are the respective cam stages of the AF cam 10. On the other hand, the motor control time T that stops even when the voltage / temperature fluctuates is shown.

The output from the AFPI 12 is "LOW".
When the level is changed, the motor control time T is started, and control is performed for a time corresponding to each cam stage.
The motor control may be motor-on control or motor duty control. As a result, the AF cam engagement portion 6g moves each cam stage of the AF cam 10 as shown in the figure by the motor control, and stops at the desired cam stage.

By the operation of the AF cam 10 as described above, the moving frame 6 is extended and the photographing lenses 2 to 4 in the lens frame 1 are moved.
Reaches the focus position and ends the autofocus operation. After this, the photographing lenses 2 to 4 are returned to the initial positions again after the photographing is completed.

At this time, the initial position of the AF cam 10 is A
The AF cam 10 is rotated in the feeding direction and rotated once so as to stop at the F cam engagement portion 6g. The AF cam 1
When the initial position of 0 is located at the AF cam engaging portion 6g, the same A
The light-shielding piece 11a of the AFPI gear 11, which rotates in synchronization with the F-cam 10, is inserted into the slit of the AFPI 12,
The output of the AFPI 12 becomes "HIGH" level.

When the position of the AF cam 10 is detected in this way, the motor 27 is braked and stopped at the initial position. In addition, by rotating the AF cam 10 in the retracting direction,
The rising edge of the output of the FPI 12 may be detected.

Next, a lens control circuit in a camera incorporating the lens driving device of this embodiment will be described with reference to the electric circuit diagram shown in FIG. Note that FIG.
Only the control circuit for (automatic focusing) is shown.

In the figure, the CPU 23 controls the operation of the entire camera in addition to the control of the lens driving device. In addition, in this camera, power is supplied from the battery 21, but when a load is driven by a motor or the like, DC / D
The voltage stabilized by the C converter 22 is supplied to the CPU 23,
The signal is supplied to the AFPI 12 and the comparator 24 for processing the photo interrupter signal.

Further, the transistors 26a to 26d form a bridge circuit, and by selectively turning on two of them, the motor (M) 27, which is the drive source of the lens driving device, is rotated normally. , Reverse rotation drive, or control such as braking by putting in a short-circuited state.

When the AF cam 10 rotates in a predetermined direction, the AFP meshed with the AF cam gear 9 as described above.
The I gear 11 rotates, and an output signal associated with the transmission / shielding of the AFPI 12 is output to the CPU 23. At this time, the collector potential of the phototransistor of the AFPI 12 is binarized through the comparator 24 and read by the CPU 23 to obtain a photointerrupter signal synchronized with the movement of the mechanical section.

Further, the distance measuring device 28 measures the distance from the signal from the CPU 23 and transfers the distance measuring data obtained thereby to the CPU 23 through the serial data bus.

The CPU 23 is provided with a plurality of terminals, and a control signal for the DC / DC converter 22 is output from the terminal 23a.
Control signals for the bridge circuit are output from 3b to 23c. Further, the output pulse signal from the AFPI 12 is input to the terminal 23g, and the AFPI 12 is input from the terminals 23h and 23i.
The control signal of is output. A control signal for the distance measuring device 28 is output from the terminal 23j, and the distance measuring device 28 is output to the terminal 23k.
The data after the distance measurement operation from is input.

FIG. 7 is a block diagram showing the internal structure of the CPU 23.

The CPU 23 stores a calculation section 53 for performing calculation based on the data sent from the distance measuring device 28, and a motor drive time T (see reference numeral 56 in the figure) corresponding to each cam stage described above. Storage area 51, an input unit 54 for inputting an output from the comparator 24, a timer 52 for counting the motor drive time T, control of the motor 27 and the DC / DC converter 22, and auto focus and the like. And a control unit 55 that controls the above.

Further, in the storage area 51, the motor drive time T corresponding to each of the above-mentioned cams is stored as a table as indicated by reference numeral 56 in the drawing. Further, as shown in FIG. 8, the storage area 51 is stored in the EEPROM 66.
If it is replaced with the register 61 and the register 61, it can be rewritten and the shape of the stepped cam can be easily changed.

Next, the lens extension control in the lens driving device of this embodiment will be described with reference to the flow chart shown in FIG.

First, in step S1, the distance measuring device 28 starts the distance measuring operation based on the control signal from the CPU 23. The distance measuring device 28 projects infrared rays onto a subject, forms a projected image on the subject on a light receiving element in the distance measuring device 28, and electrically receives a light receiving position on the light receiving element as an analog signal. Alternatively, it is converted into a digital signal and transmitted to the CPU 23.

The CPU 23 extends the taking lenses 2 to 4 based on the signal. The taking lenses 2 to 4 are A
Since it is extended along the cam stage provided on the F-cam 10, in step S2, the calculation unit 53 of the CPU 23 calculates the distance to the subject based on the distance measurement result of step S1, and the stop position cams of the photographing lenses 2 to 4 are calculated. Determine the stage.

Inside the CPU 23, the motor ON time T corresponding to the cam stage determined as described above is set in the storage area 51. Further, in step S3, the timer 52 is set in the storage area 51 of the motor ON time corresponding to the determined cam stage.

As shown in FIG. 8, in the CPU 23,
When the EEPROM 66 is provided instead of the storage area 51, the motor ON time T corresponding to the determined cam stage is set.
Is read through the register 61 and set in the timer 52.

In step S4, the DC / DC converter 2
2 is driven to stabilize the supply voltage to the CPU 23 and the AFPI 12. In step S5, the AFPI 12 (indicated by PI in the drawing) is activated. In step S6, the AFPI is set by the input unit (PI detection unit) 54 of the CPU 23.
The output of 12 is monitored, and if the output is the "L" level (transmission), the photographing lenses 2 to 4 are returned to the initial positions, so that the process proceeds to step S7 and the lens is reset.

If the output is "H" level (light-shielded) in step S6, the process proceeds to step S8 and CP
Energization of the motor 27 is started from the motor control unit 55 of U23. In step S9, it is determined whether or not the falling edge (light-shielding → transmission) is detected, and the motor 2 is detected until it is detected.
Continue to energize 7. When the falling edge is detected, the process moves to step S10 and the timer 52 of the CPU 23 starts counting.

In step S11, the motor 27 is energized again, and in step S12, the motor ON time T set in step S3 is compared with the timer time set in the timer 52, and the motor is turned on until the timer passes the time T. Continue to energize 27.

When the timer time set in the timer 52 at step S12 has passed the time T, the short brake is applied to the motor 27 for a predetermined time, and then the motor 27 is turned off, and the AFPI 12 is also turned off. The process ends (steps S513 to S516).

When the braking time of the short brake is further shortened, the reverse brake may be used.

After that, time exposure corresponding to photometry is performed and the lens is reset to the initial position. This reset operation is shown in Figure 1.
This will be described with reference to the flowchart shown in FIG.

The reset operation is similarly performed when it is determined that the taking lens is not in the initial position when the lens extension control is performed.

First, as in the lens extension control, the above D
C / DC converter 22 is driven to drive CPU 23 and A
The voltage supplied to the FPI 12 is stabilized, the AFPI 12 is put into an operating state, and the motor is driven (steps S21 to S21).
23).

If the output from the AFPI 12 (denoted by PI in the figure) is at the "L" level (transmission), the output of the AFPI 12 is at the "H" level (light-shielding) because the taking lenses 2 to 4 are at the extended position. The motor 27 is driven until () (step S24).

When the output from the AFPI 12 changes to the "H" level, the motor 27 is short braked or reversely braked and then turned off, and the AFPI 12 is also turned off (step S25-). (S28), this routine ends.

As described above, according to the above embodiment, by setting the widths of the step cams to different lengths,
It is possible to stop the taking lens at the desired stage even against voltage and temperature fluctuations. Further, the position of the photographing lens can be controlled with an extremely simple structure, and thus an inexpensive lens driving device can be provided.

FIG. 11 is a time chart showing the relationship between the AF cam and the output pulse of AFPI in the lens driving device which is a modification of the above embodiment.

This modified example corresponds to A in the first embodiment.
This is an example in which the initial position stage and the first stage cam of the F-cam 10 are formed in the same stage, and other configurations and operations are the same, so description thereof is omitted here.

Also in this modification, the autofocus control of the taking lens is performed by the same operation as that of the above-mentioned embodiment, and in addition to the same effect as that of the above-mentioned embodiment, the lens driving having a simpler structure is possible. A device can be provided.

[0072]

As described above, according to the present invention, it is possible to provide a lens drive device capable of stopping the cam corresponding to the position of the lens group at a predetermined stage by simple control under any conditions.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing a lens driving device of an embodiment of the present invention.

FIG. 2 is a perspective view of a moving frame in the lens driving device of the above embodiment as seen from the back side.

FIG. 3 is an exploded perspective view of a main part of the camera body and its peripheral part in the lens driving device of the above embodiment as viewed from the bottom side.

FIG. 4A is a plan view showing the positional relationship between the AF cam and the protrusion of the moving frame in the lens driving device of the above embodiment,
(B) It is a side view.

FIG. 5 is a time chart showing the relationship between the AF cam that extends the lens frame and the output pulse signal of AFPI in the lens driving device of the embodiment.

FIG. 6 is an electric circuit diagram showing a lens control circuit in a camera incorporating the lens driving device of the above embodiment.

FIG. 7 is a block diagram showing an internal configuration of a CPU in the lens driving device of the embodiment.

8 is a block diagram illustrating a storage area in the CPU shown in FIG.
C when replaced with EPROM and register
It is a block diagram showing an internal configuration of a PU.

FIG. 9 is a flowchart showing lens extension control in the lens driving device of the embodiment.

FIG. 10 is a flowchart showing an operation of resetting a taking lens to an initial position in the lens driving device of the above-described embodiment.

FIG. 11 is a time chart showing a relationship between an AF cam and an AFPI output pulse in a lens driving device that is a modification of the above-described embodiment.

FIG. 12 is a diagram showing a relationship between a motor energization time and a cam movement amount in a conventional one photographic lens driving device.

[Explanation of symbols]

 1 ... Mirror frame 2-4 ... Shooting lens 5 ... Leaf spring 6 ... Moving frame 6b ... Projection piece 6g ... Cam follower (AF cam engaging part) 7 ... Camera body 8 ... AF gear 9 ... AF cam gear 10 ... AF cam 11 … AFPI Gear 12… AFPI

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] January 25, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction content]

[0012]

In order to achieve the above object, the lens driving device according to the present invention is a lens driving device for moving at least one lens group in an optical system in the optical axis direction. Cam means having a plurality of step portions that abut the lens group and correspond to a plurality of different positions of the lens group in the optical axis direction, and a step in the cam means that moves the cam means and that abuts the lens group. A drive means for determining the position of the lens group in the optical axis direction by selecting a portion, and the upper portion is selected in the final state of the movement of the cam means among the plurality of step portions.
The width along the moving direction of the step where the lens group is in contact
In the initial state of movement of the cam means, the lens group
Make it wider than the width of the abutting step along the moving direction.
Characterized in that was.

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] 0070

[Correction method] Change

[Correction content]

This modified example corresponds to A in the first embodiment.
This is an example in which the initial position step and the first step cam are formed in the same step in the F cam 10, as described above.
Since the operation is the same, the description is omitted here.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0071

[Correction method] Change

[Correction content]

Also in this modification, the autofocus control of the taking lens is performed by the same operation as that of the above-mentioned embodiment, and in addition to the same effect as that of the above-mentioned embodiment, the lens driving having a simpler structure is possible. A device can be provided. Furthermore, in this modified example, the first stage cam
Since the width of can be set to substantially zero,
The last stage) and the number of cam stages
It can easily be increased.

[Procedure Amendment 5]

[Document name to be corrected] Drawing

[Name of item to be corrected] Fig. 10

[Correction method] Change

[Correction content]

[Figure 10]

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location 8411-2K G03B 3/00 A

Claims (1)

[Claims] 1. A lens driving device for moving at least one lens group in an optical axis direction in an optical system, abutting against the lens group and corresponding to a plurality of different positions of the lens group in the optical axis direction. Cam means having a plurality of step portions, and drive means for determining the position of the lens group in the optical axis direction by moving the cam means and selecting the step portion of the cam means with which the lens group abuts. , The width of the plurality of step portions along the moving direction of the cam means is such that the width from the step portion with which the lens group abuts in the initial state of the movement of the cam means to the lens in the final state. A lens driving device, characterized in that the lens driving device is formed so as to become wider as it changes to a stepped portion in contact with the group.