JPH09222548A - Lens driving mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To relax an impact at the time of abutting with the elasticity of an O-ring while keeping the screwing accuracy of a feed screw shaft and a lead gear by fitting the O-ring on the guide shaft of a lens driving mechanism adjacently to a moving end regulating member. SOLUTION: The O-ring 307 consisting of an elastic member such as rubber is fit at a part between a stopper plate 306 and a slide bearing 51a on a slide shaft 51. The O-ring 307 is a cushioning material for attenuating the impact in the case of stopping a lens supporting barrel 50 at a lens moving end when a rear group moving motor runs away in a lens extending direction for some reason or other. When the motor runs away in a lens withdrawing direction, the barrel 50 is decelerated by a rear group energizing coil spring 3 in the vicinity of the lens moving end, so that the impact in the case of stopping is relaxed. The biting of a driving gear 42a into a screw shaft 43 is prevented by the cushioning action of the O-ring 307 and the spring 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens driving mechanism for a camera, and more particularly to a shock absorber for a lens feeding mechanism.

[0002]

2. Description of the Related Art In a camera equipped with a zoom lens, zooming, focusing, etc. are performed by changing the air gap between the lenses based on photographing information. That is, the air gap between the lenses is changed by advancing and retracting the lens (group) in the optical axis direction. A so-called feed screw mechanism including a feed screw shaft and a lead gear is known as a mechanism for moving a lens. A predetermined rotation stopper is usually provided at the end of the movable member so as not to deviate from the movable range of the feed screw mechanism. If this rotation stopper is not provided,
When the movable member deviates from the movable range for some reason, so-called biting may occur between the feed screw shaft and the movable member, and the predetermined mounting accuracy may be lost.
In order to prevent such biting, in this type of feed screw mechanism, a rotation stopping member is usually provided corresponding to the end of the movable range of the movable member.

However, in today's highly demanded miniaturization cameras, in particular, lens shutter type cameras, if members are mounted in the apparatus only for the purpose of stopping rotation of the feed screw mechanism, it is not necessary to reduce the size. There is a problem that it is not possible to cope with it, and there is a strong demand for a buffer mechanism that does not occupy the space in the device and can reliably prevent the above bite.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention, based on the above-mentioned awareness, to provide a shock absorbing device which surely prevents biting in a lens feeding mechanism and does not require attachment of an auxiliary member or the like.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a first cylinder (shutter block) and a second cylinder (rear group lens) that move relative to each other in the optical axis direction; one,
A movable lens fixed to at least one of the second cylinders;
A guide shaft supported by either one of the first cylinder and the second cylinder, which guides the first cylinder and the second cylinder so as to be relatively movable in the optical axis direction; A feed screw shaft supported in parallel with the guide shaft in the same tubular body; a lead gear supported in the other of the first tubular body and the second tubular body by restricting movement in the optical axis direction; A feed mechanism that rotationally drives either one of the shaft and the lead gear; a moving end regulating member provided at the ends of the guide shaft and the feed screw shaft; an O-ring fitted to the guide shaft so as to be adjacent to the moving end regulating member. It is characterized by having.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on illustrated embodiments. In this embodiment, the present invention is applied to the lens shutter zoom lens camera shown in FIG. 13. First, the concept of this zoom lens camera will be described with reference to FIG. The lens configuration is the front lens group L
1 group and the rear lens group L2.

[0007] The camera body includes an overall movement motor control means 60, a rear group movement motor control means 61, and a zoom operation means 6.
2, a shutter release means 63, a distance measuring device 64, a photometric device 65, and an AE motor control means 66 are provided.

When the zoom operating means 62 such as a zoom lever provided on the camera body is operated, the overall movement motor control means 60 controls the overall movement motor 25 to include a zoom lens including a front lens group L1 and a rear lens group L2. A movement command for moving the camera from the wide side to the tele side or a movement command for moving the tele side to the wide side is given. The focal length is changed and set to an arbitrary focal length by the operation of the zoom operating means 62 by the photographer. The image magnification of the viewfinder field is changed in association with the change of the focal length by the zoom operation means 62. Therefore, the photographer can know the change in the focal length due to the operation of the zoom operation means 62 by observing the change in the image magnification of the viewfinder field. The focal length set by the operation of the zoom operation means 62 can be recognized by a numerical value displayed on the LCD display panel (not shown), for example.

The overall movement motor control means 60 is also driven by the rear group movement motor control means 61 when the shutter release means 63 is operated.
At the same time, the whole movement motor 25 is driven to focus the zoom lens on the subject. The shutter release means 63 is
It is composed of a release button, and when it is pressed one step, it gives a distance measuring command to the distance measuring device 64 and a photometric command to the photometric device 65, and when it is pressed two steps, it performs a focusing operation and the AE motor control means 66. The shutter 27 of the AF / AE shutter unit 21 is operated via this. The shutter 27 receives the photometric output from the photometric device 65 and opens its shutter blade 27a for a predetermined time.

When operated, the zoom operating means 62 drives the whole moving motor 25 to move the front lens group L1 and the rear lens group L2 integrally. The rear lens group moving motor 30 may be operated via the rear lens group moving motor control means 61 at the same time as this movement, but an important point in this zoom lens camera is that the front lens group L1 and the rear lens group lens by the zoom operation means 62 are operated. It means that the movement of L2 is not performed in the conventional zooming concept in which the focal length is continuously changed without moving the focal position. That is, when the zoom operation means 62 is operated, only the whole movement motor 25 is operated to move the front lens group L.
1 and the rear lens group L2 are moved back and forth without changing the air gap between them, and both the overall movement motor 25 and the rear lens group movement motor 30 are operated to operate the front lens group L1 and the rear lens group L2. It is possible to move while changing the air gap between the two.

In the aspect, the subject at a specific distance cannot always be in focus. However, in the lens shutter type camera such as the present camera which does not observe the image by the photographing optical system, the subject is focused during the shutter release. There is no problem at all as it fits. Also,

According to the above aspect, the front lens group L1 and the rear lens group L2 are moved while permitting the movement of the focal position, and both the whole movement motor 25 and the rear group movement motor 30 are operated at the time of shutter release to focus. To match.

After executing any one of the above control modes in accordance with the operation of the zoom operation means 62, the shutter release means 63 is operated in the focal length range of at least a part of the focal length set by the zoom operation means 62. Then, the whole moving motor 25 and the rear group moving motor 30
Both are operated to focus on the subject. The amount of movement of the front lens group L1 and the rear lens group L2 by the overall movement motor 25 and the rear group movement motor 30 at this time is not limited to the movement amount obtained from the subject distance information by the distance measuring device 64, and
It is determined in consideration of the movement amount obtained by the focal length information set by the zoom operation means 62. As described above, when the shutter release means 63 is operated, if the whole movement motor 25 and the rear group movement motor 30 are operated to perform the focusing operation, the degree of freedom in controlling the lens position is increased, and the control is performed. Will be easier.

Theoretically, when the zoom operating means 62 is operated, the whole moving motor 25 and the rear group moving motor 30 are operated.
The shutter release means 63 is operated by changing only the view field magnification and the focal length information of the finder without operating any of the above.
When the is operated, its focal length information and distance measuring device 64
The overall movement motor 25 and the rear group movement motor 30 are simultaneously operated according to the subject distance information according to, and the front group lens L1 and the rear group lens L2 are moved to positions uniquely determined by the focal length information and the subject distance information. You can also let it.

Next, an embodiment in which the zoom lens barrel of the above concept is embodied will be described mainly with reference to FIGS. 11 and 12. The schematic configuration and operation of the zoom lens barrel 10 will be described first. The first movable barrel 20 and the second movable barrel 20 will be described in order from the front.
A movable lens barrel 19, a third movable lens barrel 16, and a fixed lens barrel block 12 are provided. The third movable lens barrel 16 is screwed into the tubular portion of the fixed lens barrel block 12, and advances and retreats in the optical axis direction with rotation. The third movable lens barrel 16 has a linear guide cylinder 17 whose rotation is restricted, which moves integrally in the optical axis direction, inside, and the second movable lens barrel 19 rotates relative to the linear guide cylinder 17. While moving forward and backward along the optical axis. First movable lens barrel 2
0 is restricted in rotation, and moves forward and backward in the optical axis direction due to relative rotation with respect to the second movable lens barrel 19. The whole movement motor 25 is fixed to the fixed lens barrel block 12, and the shutter mount 4 having the AE motor 29 and the rear group movement motor 30 mounted thereon.
0 is fixed to the first movable lens barrel 20. The front lens group L1 is a lens having a positive power and is supported by the lens support barrel 34, and the rear lens group L2 is a lens support barrel 5.
It is a lens having a negative power supported by 0.

The fixed lens barrel block 12 fixed to the front of the aperture plate 14 of the camera body has a female helicoid 12a and a plurality of linear guide grooves 12b parallel to the optical axis O on the inner peripheral surface of its cylindrical portion. have. A code plate 13a having a predetermined pattern is fixed to the bottom of one of the plurality of straight guide grooves 12b. This code board 13
“A” is configured as a part of the flexible printed circuit board 13 located outside the fixed barrel block 12. The aperture plate 14 has an aperture 14a that determines the exposure area on the film.

A gear accommodating portion 12c, which bulges outward in the radial direction and extends in the optical axis direction, is provided in the tubular portion of the fixed lens barrel block 12.
Are formed (see FIG. 7). This gear storage 12c
The drive pinion 15 which is long in the optical axis direction is rotatably accommodated in the. Both ends of the shaft 7 of the drive pinion 15 are rotatably supported by the support hole 4 provided in the fixed lens barrel block 12 and the support hole 31a provided in the gear support plate 31, respectively. The tooth surface of the drive pinion 15 projects to the inner peripheral surface of the fixed barrel block 12.

A third movable lens barrel 16 is screwed onto the inner circumference of the fixed lens barrel block 12. This third movable lens barrel 16
Is a plurality of straight guide grooves 16 extending in the optical axis direction on the inner peripheral surface.
c, and has a male helicoid 16a that meshes with the female helicoid 12a of the fixed barrel block 12 and an outer peripheral gear 16b (see FIG. 6) that meshes with the drive pinion 15 on the outer periphery of the rear end portion. The drive pinion 15 includes a third movable lens barrel 16
Has a length in the axial direction that meshes with the outer peripheral gear 16 in the entire movement range in the optical axis direction.

A linear guide cylinder 17 is supported on the inner circumference of the third movable lens barrel 16 so as to be movable integrally with the third movable lens barrel 16 in the optical axis direction and relatively rotatable around the optical axis. . The linear guide cylinder 17 has a rear end flange portion 17d provided on the outer periphery of the rear portion with a plurality of engagement protrusions 17c protruding outward in the radial direction,
A retaining flange portion 1 having a smaller diameter than the flange portion 17d, which is provided in front of the rear end flange portion 17d with a slight gap.
7e and. A plurality of cutout portions 17f are formed in the circumferential direction of the retaining flange portion 17e. The third movable lens barrel 16 has a plurality of engagement projections 16d (FIG. 11) protruding inward in the radial direction on the inner circumference of the rear end portion.
Insert d from the above-mentioned notch 17f to insert both flanges 17
It is located in the gap between d and 17e, and is connected to the linear guide tube 17 by rotating relative to the linear guide tube 17. An aperture plate 23 having an opening 23a having substantially the same shape as the aperture 14a is fixed to the rear end surface of the linear guide cylinder 17. The engaging protrusion 17c is slidably engaged with the straight guide groove 12b parallel to the optical axis O of the fixed lens barrel block 12, and its rotation is restricted. A contact terminal 9 for slidingly contacting the code plate 13a and generating a signal corresponding to the focal length during zooming is fixed to the engaging projection 17c ', which is one of the engaging projections 17c.

The straight guide cylinder 17 also has an inner peripheral surface,
A plurality of straight guide grooves 17a parallel to the optical axis O and a plurality of lead grooves 17b penetrating the peripheral wall of the guide cylinder 17 and inclined with respect to the circumferential direction and the optical axis direction are formed.

A second movable lens barrel 19 is fitted on the inner circumference of the linear guide barrel 17. The second movable lens barrel 19 has a plurality of lead grooves 19 on the inner peripheral surface thereof, the lead grooves 19 having an inclination opposite to that of the lead grooves 17b.
c has a plurality of follower protrusions 19a having a trapezoidal cross-section, and a follower pin 18 located on the follower protrusions 19a. The follower pin 18 includes a ring member 18b and a center fixing screw 18a that supports the ring member 18b on the follower protrusion 19a. The follower protrusion 19a is
Slidably fitted in the lead groove 17b of the straight guide cylinder 17,
The follower pin 18 is the linear guide groove 1 of the third movable lens barrel 16.
6c is slidably fitted. Therefore, when the third movable lens barrel 16 rotates, the second movable lens barrel 19 rotates and moves straight in the optical axis direction.

The first movable lens barrel 20 is fitted on the inner circumference of the second movable lens barrel 19. The first movable lens barrel 20 engages a plurality of follower pins 24 provided on the outer periphery of the rear end portion with the corresponding inner peripheral lead grooves 19c, and the linear guide member 22.
Directed by. This linear guide member 22 is
As shown in FIGS. 1 and 2, an annular portion 22a, a pair of guide leg portions 22b extending from the annular portion 22a in the optical axis direction,
The straight guide groove 1 which is projected outward in the radial direction of the annular portion 22a.
7a and a plurality of engaging projections 28 slidably engaged with each other, and a guide leg portion 22b is inserted between the inner peripheral surface of the first movable lens barrel 20 and the AF / AE shutter unit 21 so as to be able to linearly guide. doing.

The annular portion 22a of the linear guide member 22 is
The second movable lens barrel 19 is coupled to the rear end of the second movable lens barrel 19 so as to be movable in the optical axis direction and rotatable relative to the optical axis. The rectilinear guide member 22 has a rear end flange portion 22d provided with a plurality of engaging projections 28 protruding outward in the radial direction on the outer periphery of the rear portion.
And a retaining flange portion 22c having a diameter smaller than that of the flange portion 22d, which is provided in front of the rear end flange portion 22d, and has a plurality of cutout portions 22e in the circumferential direction of the retaining flange portion 22c. Have (see FIG. 1). The second movable lens barrel 19 has a plurality of engagement projections 19b (FIG. 11) protruding inward in the radial direction on the inner circumference of the rear end portion. The linear guide member 22 is located in the gap between the flange portions 22c and 22d.
It is connected to the linear guide member 22 by rotating relative thereto. With the above configuration, when the second movable lens barrel 19 rotates in the forward and reverse directions, the first movable lens barrel 20 moves straight forward and backward with respect to the second movable lens barrel 19 while the rotation is restricted. To do.

A barrier device 35 having barriers 48a and 48b is attached to the front end of the first movable lens barrel 20,
The AF / AE shutter unit 2 provided with a shutter 27 including three shutter blades 27a (FIG. 5) on the inner peripheral surface.
1 is fitted and fixed. The AF / AE shutter unit 21 has a plurality of fixing holes 40a (FIG. 3) formed at equal angular intervals on the outer periphery of the shutter mount 40.
The plurality of follower pins 24 also serve as fixing means for the AF / AE shutter unit 21, and the pin hole 20a formed in the first movable lens barrel 20 and the fixing hole 40a are
The follower pin 24 is fitted and fixed, and the shutter unit 21 is fixed to the first movable lens barrel 20 (see FIG. 4). The follower pin 24 can be fixed by, for example, bonding, screwing, or the like. Incidentally, 41 is the first movable lens barrel 20.
It is a decorative plate fixed to the front end of the.

The AF / AE shutter unit 21 is shown in FIG.
As shown in FIG. 12, a shutter mount 40, a shutter blade support ring 46 fixed to the rear of the shutter mount 40, and a lens support supported so as to be movable relative to the shutter mount 40. Tube 50 (rear group lens L
2). The front lens L1, the AE motor 29, and the rear group moving motor 30 are supported by the shutter mount 40. The shutter mount 40 has an annular portion having a photographing opening 40d through which the lens support tube 34 is inserted, and three leg portions 40b extending rearward from the annular portion. Two of the gaps between the three leg portions 40b are provided in the pair of guide leg portions 2 of the rectilinear guide member 22.
It is configured as a straight-ahead guide portion 40c which slidably engages with each other and guides movement.

The shutter mount 40 further has an AE gear train 45 that transmits the rotation of the AE motor 29 to the shutter 27.
And the rotation of the rear group movement motor 30 to the screw shaft 4
3 and the photo interrupters 56 and 57 connected to the flexible printed circuit board 6.
Rotating plates 58, 5 having a number of circumferential slits
9 are supported. The photo interrupter 57 and the rotary plate 59 constitute an encoder for the rear group moving motor that detects the rotation of the rear group moving motor 30, and the photo interrupter 56 and the rotary plate 58 constitute the AE motor 29.
The encoder for the AE motor that detects the rotation of the is configured.

The shutter 2 is provided between the shutter mount 40 and the shutter blade support ring 46 fixed to the mount 40.
7, a support member 47 that pivotally supports the three shutter blades 27a of the shutter 27, and an annular drive member 49 that applies rotational force to the shutter blades 27a. The annular drive member 49 is provided with three operation protrusions 49a that engage with the three shutter blades 27a at equal angular intervals. The shutter blade support ring 46 is provided on the front wall portion with the photographing opening 4
6a and three support holes 46b provided at equal angular intervals around the photographing opening 46a, and the straight guide portion 4 is provided on the outer peripheral portion.
It has a bending restriction surface 46c exposed from 0c and slidably supporting the inner peripheral surfaces of the pair of guide leg portions 22b (see FIGS. 9 and 10).

The support member 47 located in front of the shutter blade support ring 46 includes a photographing opening 47a facing the photographing opening 46a, and three shaft portions 47b facing the three supporting holes 46b (shown in FIG. 5). Only shown). Each of the three shutter blades 27a has, at one end, a shaft hole 27b through which the shaft portion 47b is inserted, and at the other end, a shielding portion that shields the photographing openings 46a and 47a.
Between the one end and the other end, there is an elongated hole 27c through which the operation protrusion 49a is inserted. The support member 47 includes shafts 47b that respectively support the shutter blades 27a.
The shutter blade support ring 46 is fixed to the corresponding shutter hole support ring 46 in a state of being fitted into the corresponding support hole 46b.

The annular drive member 49 has a gear train 4 on its outer peripheral portion.
It has a gear portion 49b that receives rotation from 5. Further, the support member 47 has three circular arc grooves 47c along the circumferential direction at positions close to the three shaft portions 47b. The three operation protrusions 49a of the annular drive member 49 penetrate the three arcuate grooves 47c to form the elongated holes 27 of each shutter blade 27a.
c is engaged. The shutter blade support ring 46 is inserted from the rear side of the shutter mount 40 while supporting the annular driving member 49, the support member 47, and the shutter 27, and is screwed to the shutter mount 40.

At the rear of the shutter blade support ring 46, a lens support cylinder 50 supported by the shutter mount 40 via slide shafts 51 and 52 so as to be relatively movable is arranged. The shutter mount 40 and the lens support cylinder 50 are urged to move away from each other by the coil spring 3 fitted to the slide shaft 51, thereby removing play between them. The drive gear 42a provided in the gear train 42 is restricted from moving in the axial direction, and a female screw is formed on the inner periphery thereof. A screw shaft 43 whose one end is fixed to the lens support cylinder 50 is screwed into this female screw, and these drive gears 42a are
The screw shaft 43 and the screw shaft 43 constitute a feed screw mechanism. Therefore, when the rear group movement motor 30 is rotationally driven to rotate the drive gear 42a in either forward or reverse directions, the screw shaft 43 moves forward and backward with respect to the drive gear 42a, and is supported by the lens support barrel 50, that is, the support barrel 50. The rear lens group L2 moves relative to the front lens group L1.

Pressing members 53 and 55 for pressing the motors 29 and 30 supported by the shutter mount 40 are screwed to the front of the shutter mount 40. Motors 29 and 30 and photo interrupters 56 and 57 are connected to the flexible printed circuit board 6 whose one end is fixed to the shutter mount 40. In a state where the first to third movable lens barrels 20, 19, 16 and the AF / AE shutter unit 21 are assembled, the aperture plate 23 is fixed to the rear end surface of the linear guide barrel 17, and the front end of the fixed lens barrel block 12 is fixed. An annular retaining member 33 is fitted in the portion.

In this embodiment, the front lens group L1 and the rear lens group L2 are respectively provided in the AF / AE shutter unit 21.
The AE motor 29 and the rear group movement motor 30 are mounted on the unit 21 as one of the components. According to this configuration, there is an advantage that the supporting structure and the driving structure of the front group lens L1 and the rear group lens L2 can be simplified, but at least one of the front group lens L1 and the rear group lens L2 is
Shutter mount 40, annular drive member 49, support member 4
The present zoom lens can be realized even if the AF / AE shutter unit 21 including the shutter 7, the shutter 27, the shutter blade pressing ring 46, and the like is provided as a separate member and is supported by a support member different from the unit.

Next, the shock absorber of the lens feed mechanism to which the present invention is applied will be described using the moving mechanism of the rear lens group L2. More specifically, the above-mentioned shock absorber is applied to an AF home position detection mechanism described below.

The AF home position means the front lens group L1.
And the initial position of the rear lens group L2.
Use as the reference position for caching. After the shutter release is completed, the AF home position is returned. During focusing, the rear lens group L2 is moved relative to the front lens group L1 toward the rear of the optical axis O from this AF home position by an amount necessary for focusing, and the rear lens group L2 is moved relative to the front lens group L1. The AF home position is controlled so as to always be maintained when the power is turned on, after the shutter release is completed, and when the camera is stored.

14 to 17 show a mechanism for detecting the AF home position. Rear lens group support cylinder 50
Is supported by the shutter mount 40 via a pair of slide shafts 51 and 52 so as to be movable along the optical axis. One end of each of the slide shafts 51 and 52 has a shaft support boss 5 projecting from the outer peripheral surface of the lens support cylinder 50.
It is fixed to 0b and 50c. The slide shafts 51 and 52 are slidably inserted and supported by a slide bearing 51 a fixed to the shutter mount 40 and guide portions of the shutter mount 40, respectively.

One end of the screw shaft 43 is
The lens support cylinder 50 is fixed to a shaft support boss 50a that is provided on the outer peripheral surface of the lens support cylinder 50 so as to project close to the shaft support boss 50b. The screw shaft 43 is screwed to a drive gear 42a which is rotatably supported by the shutter mount 40 and the shutter 27 in a state in which axial movement is restricted. As shown in FIG. 15, the drive gear 42a has an end portion on the rear lens group L2 side which is the shutter mount 40.
Is regulated in the axial direction by one end thereof, and is regulated in the axial direction by a shaft stopper member 53a formed integrally with the pressing member 53 on the end surface on the front group lens L1 side. When the drive gear 42a is rotationally driven by the rear group movement motor 25, the screw shaft 43 moves back and forth with respect to the drive gear 42a, and the lens support barrel 50, that is, the rear group lens L2 supported by the lens support barrel 50, moves forward. It moves relative to the group lens L1. In order to eliminate the backlash between the screw shaft 43 and the drive gear 42a, the rear group biasing coil spring 3 is fitted on one slide shaft 51 between the slide bearing 51a and the shaft support boss 50b. ing. The rear group biasing coil spring 3 biases the lens support cylinder 50 in a direction away from the shutter mount 40 (rearward with respect to the shutter mount 40) to remove backlash.

At the front end of the shutter mount 40, a photo interrupter 301 and a chopper 302 which form an AF home position detection circuit 232 are mounted near the pressing member 55. The photo interrupter 301 is mounted on the flexible printed circuit board 6 and has a shutter mount 40.
It is fixed to. The chopper 302 is planted in the shutter mount 40, has a tip end slidably supported by a chopper guide shaft 303 supported by a pressing member 55, and is mounted between the chopper 302 and the pressing member 55.
Is urged toward the shutter mount 40. The chopper 302 includes a chopper plate 302a that has entered the slit of the photo interrupter 301. When the chopper 302 is in the retracted position by the urging force of the chopper urging spring 304, the optical path of the photo interrupter 301 is opened and the chopper 302 is attached. When the photo interrupter 30 is moved forward to a predetermined position against the biasing force of the biasing spring 304.
The optical path of 4 is cut off.

A stopper plate 306 is fixed to the tip ends of the screw shaft 43 and the one slide shaft 51 via a lock washer 305. Stopper plate 3
06, a chopper pressing portion that abuts a projection 302b protruding from the chopper 302 when the rear lens group support cylinder 50 moves forward and moves the projection 302b forward against the biasing force of the chopper biasing spring 304. 306a is formed. The chopper pressing portion 306a comes into contact with the projection 302b of the chopper 302 when the lens support cylinder 50 (rear group lens L2) approaches the shutter mount 40, and the chopper urging force is caused by further advancement of the lens support cylinder 50. Spring 303
Advance against the urging force of. When the rear lens group support cylinder 50 approaches the shutter mount 40, the AF
When the chopper 302 moves to the home position, the chopper plate 302a blocks the optical path of the photo interrupter 301. The CPU 210 checks whether or not the rear group lens L2 (rear group lens support barrel 50) is at the AF home position by checking the output of the photo interrupter 301.

Further, an O-ring 307 made of an elastic member such as rubber is fitted on the slide shaft 51 at a portion between the stopper plate 306 and the slide bearing 51a. The O-ring 307 attenuates the impact when the lens supporting cylinder 50 is stopped at the lens moving end when the rear lens group moving motor 30 runs away in the lens feeding direction (rear lens group L2 backward direction) for some reason. Cushioning material for. When the lens is runaway in the lens retracting direction (forward direction of the rear lens group L2), the rear group biasing coil spring 3 reduces the speed in the vicinity of the lens moving end, and the shock when stopping is buffered. The O-ring 307 and the rear group biasing coil spring 3 serve as a cushioning effect to the screw shaft 43 and the drive gear 4
Biting with 2a is prevented.

The operation of the O-ring 307 as a shock absorber will be further described. In order to ensure the cushioning action of the O-ring 307, in the state of FIG. 15, the end surface of the stopper member 53a that restricts the axial movement of the drive gear 42a and the end surface 51b of the slide bearing 51a are located at substantially the same position in the optical axis direction. Is arranged so as to become (a so-called tlitchi).

With this arrangement, if the rear lens group moving motor 30 runs away in the lens retraction direction (the rear lens group L2 forward direction) for some reason, the stopper plate 30 will be used.
Before the 6 comes into contact with the stopper member 53a, the O-ring 307
Is in contact with the end surface 51b of the slide bearing 51a, it does not affect the screwing precision of the drive gear 42a and the screw shaft 43, and the elasticity of the O-ring 307 can sufficiently absorb the impact due to contact.

Further, if the stopper plate 306 is prevented from coming into contact with the stopper member 53a first, the positions of the end face 42b and the end face 51b in the optical axis direction need not necessarily be the same (tritch). In other words, the O-ring 307 is
It suffices that the thickness in the optical axis direction be larger than the distance formed between the stopper plate 306 and the end surface 51b of the slide bearing 51a, which is formed when the stopper plate 306 comes into contact with the stopper member 53a.

The present zoom lens camera operates as follows. When the power switch (not shown) is turned on in the lens housed state of FIG. 9 in which the zoom lens barrel 10 is most retracted, the whole movement motor 25 is driven to rotate a little in the forward direction. Then, this rotation is transmitted to the drive pinion 15 via the gear train 26 supported by the support portion 32, and the third
Since the movable lens barrel 16 is rotated in the extending direction, the second movable lens barrel 19 and the first movable lens barrel 20 are slightly extended in the optical axis direction together with the third movable lens barrel 16, and the camera sets the zoom lens wide. The camera is ready to shoot at the edge.

When the zoom operation means 62 is operated to the tele side in this photographing possible state, the whole movement motor 25 is rotationally driven in the positive direction via the whole movement motor control means 60, and the driving pinion 15 and the outer peripheral gear 16b are used. The third movable lens barrel 16 is rotated in the feeding direction. Therefore,
The third movable lens barrel 16 is extended from the fixed lens barrel block 12 due to the relationship between the female helicoid 12a and the male helicoid 16a, and at the same time, the straight guide tube 17 is fixed by the relationship between the engagement projection 17c and the straight guide groove 12b. Block 12
With respect to the third movable lens barrel 16, the lens moves forward along the optical axis in a state where it does not relatively rotate. At this time, the second movable lens barrel 19
Attaches the follower pin 18 to the lead groove 17b and the straight guide groove 1
By being engaged with 6c at the same time, the third movable lens barrel 16 is relatively rotated in the same direction and relatively moved forward of the optical axis with respect to the movable lens barrel 16. Also, the first movable lens barrel 20 is
Since the linear guide member 22 linearly guides and the follower pin 24 is moved and guided by the lead groove 19c, the second movable lens barrel 19 and the AF / AE shutter unit 21 together with the fixed lens barrel block 12 do not rotate relative to each other. Advance to the front of the optical axis.

Since the rear lens group moving motor 30 is not driven while the zoom lens barrel 10 is driven in this manner, the front lens group L1 and the rear lens group L2 are integrally integrated with each other while keeping a constant distance from each other. In the direction (see FIG. 8). The focal length set by the zoom operation means 62 is displayed by the display means (not shown).

When the release button is pushed one step at an arbitrary focal length set by the zoom operating means 31, a distance measuring command is given to the distance measuring device 64 and a light measuring command is given to the light measuring device 65 to measure the distance and Photometry starts. Thereafter, when the release button is depressed two steps, both the whole moving motor 25 and the rear group moving motor 30 move the moving amount obtained by the distance measuring device 64 based on the subject distance information and the focus set by the zoom operating means 31. The AE motor control means 6 moves the front lens group L1 and the rear lens group L2 by a movement amount determined in consideration of the movement amount obtained from the distance information to set the focal length and focus on the subject.
The AE motor 29 rotationally drives the annular driving member 49 in accordance with the subject luminance information from the photometric device 65 via 6 to drive the shutter 27 so as to satisfy a predetermined exposure. After completion of the shutter release, both the whole movement motor 25 and the rear group movement motor 30 are immediately driven to return the front group lens L1 and the rear group lens L2 to the state before the shutter release.

When the zoom operating means 62 is operated to the wide side, the whole moving motor 25 is rotationally driven in the reverse direction, and
The movable lens barrel 16 is rotated in the retracting direction and retracted into the fixed lens barrel block 12 together with the linear guide barrel 17. At the same time, the second movable lens barrel 19 is retracted with respect to the movable movable lens barrel 16 while rotating in the same direction as the third movable lens barrel 16.
The movable lens barrel 20 has a position A relative to the rotating second movable lens barrel 19.
It is pulled in together with the F / AE shutter unit 21.
Also during this retraction drive, the rear group moving motor 30 is not driven, as in the above-described retraction drive. Then, when the power switch is turned off after the zoom lens has moved to the wide end position, the zoom lens barrel 10 is retracted to the lens storage position shown in FIG. 11 by the overall movement motor 25 that is rotationally driven based on this.

[0048]

As is apparent from the above description, according to the present invention, since the O-ring is fitted to the guide shaft of the lens driving mechanism so as to be adjacent to the moving end regulating member, the moving end regulating member is first attached to the lead gear. Since the contact can be prevented, the impact of the contact can be sufficiently buffered by the elasticity of the O-ring while maintaining the screwing accuracy of the feed screw shaft and the lead gear.

[Brief description of drawings]

FIG. 1 is a perspective view showing a main part of an embodiment of a straight guide mechanism to which the present invention is applied.

FIG. 2 is a perspective view showing a state different from that of FIG. 1 of a main part of the linear guide mechanism.

FIG. 3 is a perspective view showing a main part of a zoom lens barrel in the present embodiment.

FIG. 4 is a perspective view showing a state where the AF / AE shutter unit of the zoom lens barrel is assembled to the first moving lens barrel.

FIG. 5 is an exploded perspective view showing main members of an AF / AE shutter unit of the zoom lens barrel.

FIG. 6 is a perspective external view showing a third movable lens barrel of the zoom lens barrel.

FIG. 7 is a front view showing a fixed barrel block of the zoom lens barrel.

FIG. 8 is an upper half sectional view showing a maximum extended state of the zoom lens barrel.

FIG. 9 is an upper half sectional view showing a main part of the zoom lens barrel in a lens housed state.

FIG. 10 is an upper half sectional view showing a main part of the same zoom lens barrel in a maximum extended state.

FIG. 11 is an upper half cross-sectional view showing a lens storage state of the entire zoom lens barrel.

FIG. 12 is an exploded perspective view showing the entire zoom lens barrel.

FIG. 13 is a block diagram showing a control system for controlling the operation of the zoom lens barrel.

FIG. 14 is an enlarged perspective view showing a lens driving mechanism according to the present invention.

FIG. 15 is an enlarged plan view of a lens driving mechanism.

FIG. 16 is an enlarged sectional view of a lens driving mechanism.

FIG. 17 is an enlarged sectional view of a lens driving mechanism.

[Explanation of symbols]

 21 shutter unit 42 lens drive gear train 42a drive gear 43 screw shaft 43 50 rear group lens support cylinder 51 slide shaft 51a slide bearing 306 stopper plate 307 O-ring L2 rear group lens

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[Procedure amendment]

[Submission date] March 28, 1997

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0001

[Correction method] Change

[Correction contents]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens driving mechanism for a camera, and more particularly to a lens driving mechanism provided with a shock absorber for a lens feeding mechanism.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction contents]

[0004]

It is an object of the present invention to provide a lens drive mechanism equipped with a shock absorber which surely prevents biting in the lens feed mechanism and does not require attachment of an auxiliary member or the like, based on the above-mentioned awareness. With the goal.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0005

[Correction method] Change

[Correction contents]

[0005]

SUMMARY OF THE INVENTION To achieve the above object, the present invention provides a first cylinder and a second cylinder which move relative to each other in the direction of the optical axis; and are fixed to at least one of the first cylinder and the second cylinder. Lens group; a guide shaft supported by either one of the first cylinder and the second cylinder for guiding the first cylinder and the second cylinder so as to be relatively movable in the optical axis direction; A feed screw shaft that is supported in parallel with the guide shaft in the same cylinder that supports the shaft;
A lead gear that is supported by the other of the first cylinder and the second cylinder while restricting movement in the optical axis direction; a feed mechanism that rotationally drives one of the feed screw shaft and the lead gear; the guide shaft and the feed screw shaft. A moving end restricting member provided at the end of; and an O-ring fitted to the guide shaft so as to be adjacent to the moving end restricting member.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction contents]

A third movable lens barrel 16 is screwed onto the inner circumference of the fixed lens barrel block 12. This third movable lens barrel 16
Is a plurality of straight guide grooves 16 extending in the optical axis direction on the inner peripheral surface.
c, and has a male helicoid 16a that meshes with the female helicoid 12a of the fixed barrel block 12 and an outer peripheral gear 16b (see FIG. 6) that meshes with the drive pinion 15 on the outer periphery of the rear end portion. The drive pinion 15 includes a third movable lens barrel 16
Has a length in the axial direction that meshes with the outer peripheral gear 16b in the entire movement range in the optical axis direction.

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0021

[Correction method] Change

[Correction contents]

A second movable lens barrel 19 is fitted on the inner circumference of the linear guide barrel 17. The second movable lens barrel 19 has a plurality of lead grooves 19 on the inner peripheral surface thereof, the lead grooves 19 having an inclination opposite to that of the lead grooves 17b.
c has a plurality of follower protrusions 19a having a trapezoidal cross-section, and a follower pin 18 located on the follower protrusions 19a. The follower pin 18 includes a ring member 18a and a center fixing screw 18b that supports the ring member 18a on the follower protrusion 19a. The follower protrusion 19a is
Slidably fitted in the lead groove 17b of the straight guide cylinder 17,
The follower pin 18 is the linear guide groove 1 of the third movable lens barrel 16.
6c is slidably fitted. Therefore, when the third movable lens barrel 16 rotates, the second movable lens barrel 19 rotates and moves straight in the optical axis direction.

[Procedure amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0033

[Correction method] Change

[Correction contents]

Next, a shock absorber for a lens feed mechanism to which the present invention is applied will be described. This shock absorber is applied to an AF home position detection mechanism described below.

[Procedure amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0034

[Correction method] Change

[Correction contents]

The AF home position means the front lens group L1.
Is an initial position of the rear lens group L2 with respect to, and this position is used as a reference position for focusing. After the shutter release is completed, the AF home position is returned. During focusing, the rear lens group L2 is moved relative to the front lens group L1 toward the rear of the optical axis O from this AF home position by an amount necessary for focusing, and the rear lens group L2 is moved relative to the front lens group L1. The AF home position is controlled so as to always be maintained when the power is turned on, after the shutter release is completed, and when the camera is stored.

[Procedure amendment 9]

[Document name to be amended] Statement

[Correction target item name] 0036

[Correction method] Change

[Correction contents]

One end of the screw shaft 43 is
The lens support cylinder 50 is fixed to a shaft support boss 50a that is provided on the outer peripheral surface of the lens support cylinder 50 so as to project close to the shaft support boss 50b. The screw shaft 43 is screwed to a drive gear 42a which is rotatably supported by the shutter mount 40 and the shutter 27 in a state in which axial movement is restricted. As shown in FIG. 15, the drive gear 42a has an end portion on the rear lens group L2 side which is the shutter mount 40.
Is regulated in the axial direction by one end thereof, and is regulated in the axial direction by a shaft stopper member 53a formed integrally with the pressing member 53 on the end surface on the front group lens L1 side. When the drive gear 42a is rotationally driven by the rear group movement motor 30, the screw shaft 43 moves back and forth with respect to the drive gear 42a, and the lens support barrel 50, that is, the rear group lens L2 supported by the lens support barrel 50, moves forward. It moves relative to the group lens L1. In order to eliminate the backlash between the screw shaft 43 and the drive gear 42a, the rear group biasing coil spring 3 is fitted on one slide shaft 51 between the slide bearing 51a and the shaft support boss 50b. ing. The rear group biasing coil spring 3 biases the lens support cylinder 50 in a direction away from the shutter mount 40 (rearward with respect to the shutter mount 40) to remove backlash.

[Procedure amendment 10]

[Document name to be amended] Statement

[Correction target item name] 0037

[Correction method] Change

[Correction contents]

At the front end of the shutter mount 40, a photo interrupter 301 and a chopper 302 which form an AF home position detection circuit 232 are mounted near the pressing member 55. The photo interrupter 301 is mounted on the flexible printed circuit board 6 and has a shutter mount 40.
It is fixed to. The chopper 302 has a holding member 53.
Of which the tip end is slidably supported by the chopper guide shaft 303 supported by the pressing member 55, and is moved toward the shutter mount 40 by the chopper biasing spring 304 mounted between the pressing member 55 and the chopper guide shaft 303. Being energized. The chopper 302 includes a chopper plate 302a that has entered the slit of the photo interrupter 301. When the chopper 302 is in the retracted position by the urging force of the chopper urging spring 304, the optical path of the photo interrupter 301 is opened and the chopper 302 is attached. The optical path of the photo interrupter 304 is blocked when the photo interrupter 304 is advanced to a predetermined position against the biasing force of the biasing spring 304.

[Procedure amendment 11]

[Document name to be amended] Statement

[Correction target item name] 0038

[Correction method] Change

[Correction contents]

A stopper plate 306 is fixed to the tip ends of the screw shaft 43 and the one slide shaft 51 via a lock washer 305. Stopper plate 3
06, a chopper pressing portion that abuts a projection 302b protruding from the chopper 302 when the rear lens group support cylinder 50 moves forward and moves the projection 302b forward against the biasing force of the chopper biasing spring 304. 306a is formed. The chopper pressing portion 306a comes into contact with the projection 302b of the chopper 302 when the lens support cylinder 50 (rear group lens L2) approaches the shutter mount 40, and the chopper 302 is moved further by the lens support cylinder 50 moving forward. It moves forward against the urging force of the chopper urging spring 303. Then, when the rear lens group support cylinder 50 approaches the shutter mount 40 and moves to the AF home position, the chopper 302 is moved by the chopper plate 302a.
The optical path of 01 is cut off. A CPU (not shown) checks the output of the photo interrupter 301 to detect whether the rear group lens L2 (rear group lens support barrel 50) is at the AF home position.

[Procedure amendment 12]

[Document name to be amended] Statement

[Correction target item name] 0041

[Correction method] Change

[Correction contents]

With such an arrangement, if the rear lens group moving motor 30 runs away in the lens moving direction (rear lens group L2 backward direction) for some reason, the stopper plate 30 will be used.
Before the 6 comes into contact with the stopper member 53a, the O-ring 307
Is in contact with the end surface 51b of the slide bearing 51a, it does not affect the screwing precision of the drive gear 42a and the screw shaft 43, and the elasticity of the O-ring 307 can sufficiently absorb the impact due to contact.

[Procedure amendment 13]

[Document name to be amended] Statement

[Correction target item name] 0046

[Correction method] Change

[Correction contents]

When the release button is pushed one step at an arbitrary focal length set by the zoom operating means 62, a distance measuring command is given to the distance measuring device 64 and a light measuring command is given to the light measuring device 65 to measure the distance and Photometry starts. After that, when the release button is double-pressed, both the total movement motor 25 and the rear group movement motor 30 are moved by the object distance information from the distance measuring device 64 and the focus set by the zoom operation means 62. The front lens group L1 and the rear lens group L2 are moved by a movement amount determined in consideration of the movement amount obtained from the distance information to set the focal length and focus on the subject, and the AE motor control means 6 is provided.
The AE motor 29 rotationally drives the annular driving member 49 in accordance with the subject luminance information from the photometric device 65 via 6 to drive the shutter 27 so as to satisfy a predetermined exposure. After completion of the shutter release, both the whole movement motor 25 and the rear group movement motor 30 are immediately driven to return the front group lens L1 and the rear group lens L2 to the state before the shutter release.

[Procedure Amendment 14]

[Document name to be amended] Statement

[Correction target item name] Brief description of drawings

[Correction method] Change

[Correction contents]

[Brief description of drawings]

FIG. 1 is a perspective view showing a main part of a rectilinear guide mechanism of a zoom lens barrel to which the present invention has been applied.

FIG. 2 is a perspective view showing a state different from that of FIG. 1 of a main part of the linear guide mechanism.

FIG. 3 is a perspective view showing a main part of a zoom lens barrel in the present embodiment.

FIG. 4 is a perspective view showing a state where the AF / AE shutter unit of the zoom lens barrel is assembled to the first moving lens barrel.

FIG. 5 is an exploded perspective view showing main members of an AF / AE shutter unit of the zoom lens barrel.

FIG. 6 is a perspective external view showing a third movable lens barrel of the zoom lens barrel.

FIG. 7 is a front view showing a fixed barrel block of the zoom lens barrel.

FIG. 8 is an upper half sectional view showing a maximum extended state of the zoom lens barrel.

FIG. 9 is an upper half sectional view showing a main part of the zoom lens barrel in a lens housed state.

FIG. 10 is an upper half sectional view showing a main part of the same zoom lens barrel in a maximum extended state.

FIG. 11 is an upper half cross-sectional view showing a lens storage state of the entire zoom lens barrel.

FIG. 12 is an exploded perspective view showing the entire zoom lens barrel.

FIG. 13 is a block diagram showing a control system for controlling the operation of the zoom lens barrel.

FIG. 14 is an enlarged perspective view showing a lens driving mechanism according to the present invention.

FIG. 15 is an enlarged plan view of a lens driving mechanism.

FIG. 16 is an enlarged sectional view of a lens driving mechanism.

FIG. 17 is an enlarged sectional view of a lens driving mechanism.

[Procedure Amendment 15]

[Document name to be amended] Drawing

[Correction target item name] Fig. 1

[Correction method] Change

[Correction contents]

FIG.

[Procedure Amendment 16]

[Document name to be amended] Drawing

[Correction target item name] Figure 2

[Correction method] Change

[Correction contents]

[Fig. 2]

[Procedure amendment 17]

[Document name to be amended] Drawing

[Correction target item name] Figure 3

[Correction method] Change

[Correction contents]

[Figure 3]

[Procedure amendment 18]

[Document name to be amended] Drawing

[Correction target item name] Fig. 4

[Correction method] Change

[Correction contents]

FIG. 4

[Procedure amendment 19]

[Document name to be amended] Drawing

[Correction target item name] Fig. 8

[Correction method] Change

[Correction contents]

[Figure 8]

[Procedure amendment 20]

[Document name to be amended] Drawing

[Correction target item name] FIG.

[Correction method] Change

[Correction contents]

FIG. 14

[Procedure amendment 21]

[Document name to be amended] Drawing

[Correction target item name] FIG.

[Correction method] Change

[Correction contents]

FIG.

[Procedure amendment 22]

[Document name to be amended] Drawing

[Correction target item name] FIG.

[Correction method] Change

[Correction contents]

FIG. 16

[Procedure amendment 23]

[Document name to be amended] Drawing

[Correction target item name] FIG.

[Correction method] Change

[Correction contents]

FIG.

Claims (7)

[Claims] 1. A first cylinder and a second cylinder that move relative to each other in the optical axis direction; a movable lens fixed to at least one of the first and second cylinders; the first cylinder and the second cylinder. A guide shaft that guides the second cylinder so as to be relatively movable in the optical axis direction and that is supported by either the first cylinder or the second cylinder; the same cylinder that supports this guide shaft. A feed screw shaft that is supported in parallel with the guide shaft; a lead gear that is supported by the other of the first cylinder and the second cylinder while restricting movement in the optical axis direction; one of the feed screw shaft and the lead gear. A feed mechanism for rotationally driving the guide shaft; a moving end regulating member provided at ends of the guide shaft and the feed screw shaft; an O-ring fitted to the guide shaft so as to be adjacent to the moving end regulating member. Lens drive mechanism. 2. The lens driving mechanism according to claim 1, wherein the lens driving mechanism is mounted on a zoom lens including a front group and a rear group, and the movable lens is a rear group lens. 3. The lens drive mechanism according to claim 1, wherein the first cylindrical body is a shutter block. 4. The lens drive mechanism according to claim 1, wherein the second cylindrical body is a rear lens group. 5. The lens driving mechanism according to claim 1, wherein the movement end regulating members are the same member, and the guide shaft and the feed screw shaft are respectively supported at predetermined different positions. 6. The O-ring according to claim 1, wherein the O-ring is brought into contact with a predetermined portion of the second tubular body before the moving end regulating member comes into contact with the member regulating the axial movement of the lead gear,
Lens drive mechanism to be arranged. 7. The lens driving mechanism according to claim 1, wherein the O-ring is an elastic member.