JPH07294991A - Blur preventing device - Google Patents

Abstract

PURPOSE:To obtain a blur preventing device reducing fluctuations in a load in the driving direction of a blur preventing lens and properly and surely holding it with simple and inexpensive structure. CONSTITUTION:The blur preventing device is provided with a blur preventing optical system 8 moved for preventing the blur of an image, driving force generating devices 30 and 31 generating driving force for driving the optical system 8, a moving amount generating mechanism part generating a moving amount for moving the optical system 8 from the driving force of the driving force generating parts 30 and 31 and an energizing mechanism part, energizing the optical system 8 against the moving amount generating mechanism part and constituted so that the energizing mechanism part, energizes the optical system 8 against the moving amount generating mechanism part with energizing force 1.5 to 5 times the weight of the optical system 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shake prevention device suitable for use in a camera or the like to prevent image shake due to camera shake.

[0002]

2. Description of the Related Art Recent cameras are highly automated due to remarkable digitization in various parts such as an automatic exposure mechanism and an autofocus mechanism. However, in this type of camera, there is a countermeasure against image shake due to camera shake that is likely to occur during handheld shooting, etc., which is insufficient as an attempt for automation.

For this reason, in this type of camera, in order to prevent image shake caused by camera shake, particularly camera shake or tilt, the shake condition of the camera is detected by shake detecting means, and the detection result is detected. A shake prevention device having a structure in which the photographing lens system (main optical system) or a part of the optical system is used as a shake prevention optical system (shake prevention lens), and is shifted in a direction orthogonal to the optical axis. However, it is conventionally known.

That is, in a camera having such a shake prevention function, a shake prevention optical system (hereinafter referred to as a shake prevention lens) which constitutes at least a part of a photographing lens system is movably supported, and this shake prevention lens is used. By moving in a direction that absorbs shake in a plane orthogonal to the optical axis of the main optical system, the deviation of the image forming position due to shake is corrected,
It was to eliminate the image blur.

In such an anti-shake apparatus, as a drive mechanism for shifting the anti-shake lens, a mechanism portion such as disclosed in Japanese Patent Laid-Open No. 3-110530 is proposed. In this conventional example, the lens frame of the shake prevention lens is held so as to be movable in the direction orthogonal to the optical axis, and the lens frame is provided with drive means (motor, gear train, lever or screw shaft, ball and V-shaped groove, etc.). ) Is actuated via a connecting means (by a rod member or a drive shaft) that transmits the driving force from the above (1) as a pressing force and a pulling force, the anti-shake lens is directly driven and moved.

[0006]

By the way, in the conventional anti-shake device as described above, in order to drive and control the anti-shake lens according to the shake condition, it is necessary to drive the anti-shake lens at high speed and with high accuracy. desired. For this purpose, it is necessary to reduce the fluctuation of the load due to the driving direction when the anti-shake lens is driven, and the anti-shake lens must be held appropriately and surely.

The present invention has been made in view of the above circumstances, and has a simple and inexpensive structure to reduce the fluctuation of the load depending on the driving direction of the image stabilizing lens, and
An object of the present invention is to obtain a shake prevention device that holds a shake prevention lens appropriately and surely.

[0008]

In order to achieve the above object, the present invention provides an anti-shake optical system that is movable to prevent image blur, and a driving force for driving the anti-shake optical system. A driving force generating device, a moving amount generating mechanism section that generates a moving amount for moving the shake preventing optical system from the driving force of the driving force generating device, and the moving amount generating mechanism that controls the shake preventing optical system. And a biasing mechanism portion for biasing the biasing mechanism portion, wherein the biasing mechanism portion has a weight of 1.
The anti-shake optical system is biased to the movement amount generating mechanism section by a biasing force in the range of 5 times to 5 times.

[0009]

According to the present invention, the anti-shake optical system is configured to urge the movement amount generating mechanism section with an urging force in the range of 1.5 times to 5 times the weight of the anti-shake optical system. The force of the spring supporting the shake prevention lens can be set to an appropriate amount, the shake prevention lens can be reliably supported, and the shake prevention can be accurately performed even when the shake prevention lens is driven in all directions.

[0010]

1 to 7 show an embodiment of a shake preventing device according to the present invention. In these drawings, first, a photographing lens system with a lens shutter to which the present invention is applied is provided. The schematic configuration of the camera will be briefly described with reference to FIG. 7. That is, the taking lens system 2 which is the main optical system in the camera denoted by reference numeral 1 as a whole includes a first lens group 4 and a second lens group 9 including front and rear lens groups 7 and 8.
And a third lens group 11, and is configured as a zoom lens.

Here, the first lens group 4 is constructed by holding three lenses 4a, 4b and 4c on the lens frame 3. The second lens group 9 is composed of a total of seven lenses by holding three lenses, four lenses 7a, 7b, 7c; 8a, 8b, 8c, 8d in the lens frames 5, 6. . The third lens group 11 is configured by holding three lenses 11a, 11b, 11c on the lens frame 10.

Reference numeral 12 in the drawing denotes a lens shutter, which is provided between the front lens group 7 and the rear lens group 8 of the above-mentioned second lens group 9, and is provided with shutter shutters 13 and 14 and a drive unit for driving the same. It is composed of 15 parts. The drive unit 1
5 is arranged in the second lens group 9 on the outer periphery of the lens frame 5 of the front lens group 7, and the shutter curtains 13 and 14 are provided.
Is disposed immediately before the rear lens group 8 that functions as an image blur prevention lens described later.

Further, reference numeral 16 in the drawing denotes the first, second and third lens groups 4, 9, which constitute the above-mentioned taking lens system 2.
An image forming surface of a film on which a subject image is formed by 11 and I in the drawing is an optical axis of the taking lens system 2. Further, according to the present embodiment, in the taking lens system 2 having the three lens groups 4, 9 and 11 as described above, the rear lens group 8 of the second lens group 9 is used as an image blur preventing lens. By shifting in the direction orthogonal to the axis I, the image blur prevention mechanism unit 20 as shown in FIGS. 1 and 3 to 5 is used to move the image formed on the image plane 16 in accordance with the image blur state. Is configured to let.

Such an image blur prevention mechanism section 20 is provided with a second image stabilization mechanism as shown in FIGS. 1, 3 to 5 and FIG.
The substrate 21 on the lens shutter 12 side is provided as a base member in the space on the outer peripheral side of the rear lens group 8 in the lens group 9. Such an image blur prevention mechanism unit 20
In the rear lens group 8 in the second lens group 9
As will be apparent from FIGS. 1 and 3 to 5, the shake prevention lens 8 (hereinafter referred to as the shake prevention lens 8) is fixed and held in the lens frame 6.

Further, the substrate 21 is provided on the outer peripheral portion of the lens frame 6.
The flange portion 6 is provided at a portion facing the opening portion 21a of the
a is provided. 1 and FIG. 5 are provided at the portions where the flange portion 6a and the substrate opening portion 21a face each other.
As is clear from the above, the receiving members 67 and 69 made of a high hardness material such as hardened steel for receiving the balls 70, 71, 72 and 73 positioned and held by the through holes of the retainer member 68 are additionally provided. The balls 70,7
1, 72, 73 are held in a state of being sandwiched by these receiving members 67, 69, whereby the lens frame 6
Is the flange portion 6a, the receiving member 67, the balls 70 to 73.
It is movable with respect to the opening 21a of the substrate 21 via the.

That is, the retainer member 68 is formed with through holes in which the balls 70, 71, 72, 73 are rotatably held therein, which are arranged at equal intervals in the circumferential direction. Further, the lens frame 6 has arms 6f and 6g provided on a part of its outer peripheral portion.
The springs 51 and 52 are bridged between the base plate 21 and the base plate 21, so that the receiving members 67 and 69 are connected to the balls 70 to 70.
It is always in contact with 73.

With such a structure, the shake prevention lens 8
Is movably supported in a plane orthogonal to the optical axis I with a low load, and is constantly urged by the springs 51 and 52, so that there is no problem that the optical performance deteriorates due to tilting. . In addition, in FIG.
Although 0 and 71 are shown only at two places, they may be arranged at four places around the opening 21a of the substrate 21 and between the flange 6a and the balls 72 and 73 as shown in FIG. .

Reference numerals 30 and 31 in FIG. 1 are x-axis and y-axis DC motors (Mx, in the figure) serving as driving means for moving the image blur prevention lens 8 in the x-axis direction and the y-axis direction.
My is attached), and is attached and fixed to the substrate 21 side. Further, 32 and 33 are those motors 30 and 31.
Gears 32a, 32b, 32c, 3 for transmitting driving force from
2d; 33a, 33b, 33c, 33d for transmission of rotation of the gear train, the rotation of which is the first and second shafts 34, 3
5 is transmitted. These first and second shafts 34, 35 are
Bearings 21b, 21c or 21 provided on the substrate 21
The d and 21e are rotatably supported by extending in the x-axis direction or the y-axis direction.

The gears 32b, which form the gear trains 32 and 33 for transmitting the rotations from the above-mentioned motors 30 and 31,
32c; 33b and 33c are rotatably fixed on the substrate 21, respectively, and the gears 32d and 33d are provided on the shaft 3 respectively.
It is configured to be rotatable integrally with 4, 35. 36,3
Reference numeral 7 is a movable member on the x-axis side and the y-axis side.
The moving amount generating mechanism is configured to move the lens frame 6 in the x-axis and the y-axis directions via the movable members 36 and 37 by the feed screw mechanism which is screwed to the male screw portions 34a and 35a. Has been done.

Further, in each of the movable members 36 and 37, the guide member 5 is provided adjacent to the female screw portions 36a and 37a.
5,56 are fixed. These guide members 55,
As shown in FIG. 3, reference numeral 56 denotes the bearing portion 2 of the substrate 21.
It is guided by guide shafts 57 and 58 which are fixed to 1b and 21d or 21c and 21e in parallel with the shafts 34 and 35. The movable members 36 and 37 are connected to the motors 30 and 3 respectively.
1 can move in the x-axis direction and the y-axis direction, respectively.

The flange portion 6a of the lens frame 6 has a
As is clear from FIGS. 1 and 4, the rollers 59, 60, 6
1, 62 are rotatably attached by roller shafts 63, 64, 65, 66. Further, the spring hook portion 6b on the opposite side of the rollers 59 and 60 of the lens frame 6, the roller 61,
Between the spring hook portion 6c on the opposite side of 62 and the substrate 21,
As shown in FIGS. 1 and 4, each of the springs 53 and 54 has an x-axis direction in which the movable members 36 and 37 move,
It is bridged in the same direction as the y-axis direction.

The rollers 59, 60 and 61, 6
2 is in contact with the contact portions 36b, 36c or 37b, 37c having a substantially L-shaped cross section at the tips of both the movable members 36, 37 by the biasing force of the springs 53, 54. Therefore, the shake prevention lens 8 described above is used.
Shifts following the moving direction of the movable member 36 (x-axis direction) by the motor 30 on the x-axis side, but is free in the y-axis direction. Further, this shake prevention lens 8 is
The movable direction of the movable member 37 (y
It shifts following the (axial direction), but is free in the x-axis direction. From this, the shake prevention lens 8 is
It is possible to shift in all directions inside one opening 21a.

Further, the lens frame 6 is provided by the springs 53 and 54.
The lens frame 6 and the movable members 36, 37 are always in contact with each other by urging the movable members 36, 37 in substantially the same directions as the x-axis direction and the y-axis direction, which are the movable directions.
As a result, the movements of the movable members 36 and 37 can be reliably transmitted to the lens frame 6. Further, by the urging force of the springs 53 and 54, the male screw portions 34a and 35a of the shafts 34 and 35, which are rattled in the thrust direction of the shafts 34 and 35, and the movable member 36,
The rattling at the screwed portion of the female screw portions 36a and 37a of 37,
Can always be taken in each biasing direction. Therefore, the driving force of each of the motors 30 and 31 can be accurately and reliably transmitted to the shake prevention lens 8.

The small gears 32d and 33d include:
As is clear from FIGS. 1 and 2 (a) and (b),
The limiting gears 80x and 80y are in mesh with each other. The limiting gears 80x and 80y are rotatably supported by the gear bearing portions 21f and 21h of the substrate 21. These limiting gears 80x and 80y are portions that characterize the present invention as limiting means, and their functions will be described below with reference to FIGS. 2 (a) and 2 (b).

2A corresponds to the arrow IIa in FIG. 1 and shows the relationship between the x-axis gear 32d and the limiting gear 80x. In addition, (b) of the figure corresponds to arrow IIb in FIG.
The relationship between the shaft gear 33d and the limiting gear 80y is shown. Grooves 80xa, 8 having a substantially C-shape are formed on the back surface side (the movable member 36, 37 side in FIG. 1) of these limiting gears 80x, 80y.
0ya is formed. And these grooves 80x
a, 80ya, the convex portion 21 protruding from the gear bearing portions 21f, 21h at a portion substantially opposite to the gears 32d, 33d.
g, 21i is facing.

Therefore, these limiting gears 80x, 8
0y does not rotate 180 degrees in both directions, so that the rib portions 80xb, 80y of the limiting gears 80x, 80y are not rotated.
b comes into contact with the convex portions 21g and 21i and mechanically limits the rotation. Here, as shown in (a) and (b) of FIG. 2, with the convex portions 21g and 21i positioned at the centers of the grooves 80xa and 80ya of the limiting gears 80x and 80y, the shake prevention lens 8 is positioned at the center position. (The position where the optical axis of the shake prevention lens 8 and the optical axis I coincide with each other) is set, and the shift amount of the shake prevention lens 8 and the rotation angle of the limiting gears 80x and 80y are matched to each other. The shift amount can be limited within a predetermined range. At this time, when the rotation is limited by the limiting means described above, the motors 30, 31 are
Is stopped and the state is maintained for a certain period of time, so that the power is turned off.

Further, in such a configuration, the limiting gear 80
Since the x and 80y rotations are mechanically limited, it is effective when a runaway problem or the like occurs in the electric control system. Here, a method of detecting the position and speed of the prevention lens 8 will be described below.

That is, the gear 3 shown in FIG. 1 and FIG.
Disks with holes 40x and 40y that are provided integrally with 2a and 33a and that have a large number of holes at equal intervals in the peripheral portion, and a photo interrupter that is provided on the substrate 21 side by sandwiching the peripheral portions. 41x and 41y make the disc 40
x. The number of holes on the 40y side is detected as a pulse signal and counted.

Such position detection is carried out by (a) of FIG.
In (b), for example, when the gears 32d and 33d are rotated in the arrow "-" direction, the shake prevention lens 8 shifts to the lower left direction in FIG. 1 and reaches the limit position. The position is detected by counting pulses with the photo interrupters 41x and 41y with this position as the origin. The speed is determined by detecting the speed of the pulse.

Therefore, an encoder including the discs with holes 40x and 40y and the photo interrupters 41x and 41y is provided on the output shafts of the motors 30 and 31, and the limiting gears 80x and 80y are provided via the reduction gear train. Because
The operation limit position and the operation angle of the limit gears 80x and 80y can be detected with high resolution. Furthermore, the limiting gears 80x, 8
By setting the operating rotation angle of 0y to an angle smaller than 360 degrees, the shake prevention lens 8 is provided with one limiting gear each.
The shift range of can be limited to a predetermined range.

Further, the anti-vibration lens 8 has a limiting gear 80.
In addition to x and 80y, the driving is performed via a feed screw mechanism that is a movement amount generating mechanism, so that the shake preventing lens 8 is not directly loaded, and the shake preventing lens 8 is highly accurate.
Can be limited to a predetermined range. With such a configuration, in the driving force transmission mechanism portion from the motors 30, 31 to the lens frame 6, the shafts 34, 35 of the reduction gear systems 32, 33 and their bearing portions, and the shafts and bearing portions of the limiting gears 80x, 80y. The force acting on is minimized to prevent unnecessary rattling and wear problems over time. Further, in this way, the limiting gear 80
When x and 80y are provided and the rotation is restricted within one rotation, the gear ratio in the reduction gear trains 32 and 33 and the degree of freedom of the lead angle in the feed screw mechanism (movement amount generating mechanism). Has the advantage of being increased.

In this embodiment, the motors 30 and 31 are
Although the driving force of the driving mechanism is transmitted to the movable members 36 and 37 via the screw mechanism, it is a mechanism for converting not only the screw mechanism but also the rotary motion into the linear motion. It goes without saying that the existing mechanism can also be applied. In the above-described embodiment, the limiting gears 80x and 80y as the limiting means are engaged with the final gears 32d and 33d of the reduction gear trains 32 and 33 in the driving force transmission mechanism. Needless to say, it may be bonded to any position of. In this case, coupling to a gear near the end of the gear train is advantageous from the viewpoint of reduction gear ratio and the like.

According to the image blur preventing mechanism 20 having the above-described structure, the rear lens group (anti-vibration lens) 8 of the second lens group 9 shown in FIG. 7 is arranged in the direction orthogonal to the lens optical axis I. By shifting, the image formed on the image forming surface 16 can be moved in a desired state, and as a result, image blur can be prevented. Further, according to the image blur prevention mechanism section 20 described above, the DC motor 3 having a relatively large volume is used.
0 and 31 can be arranged such that the longitudinal direction thereof is in a positional relationship orthogonal to the optical axis I of the photographing lens group 2, and as is clear from FIGS. It is not necessary to project the motors 30 and 31 to the lens shutter 12 or the third lens group 11 side, and the motors 30 and 31 can be assembled into the outer peripheral side of the lens frame 6 of the shake prevention lens 8 in a high-density and compact unit. It is possible and advantageous in terms of structure and assembly.

Therefore, according to such an image blur prevention mechanism 20, the space of the lens shutter 12 and the distance between the second lens group 9 and the third lens group 11 are not damaged. In addition, since it can be easily unitized as described above, it is excellent in assembling, and is very effective even if it is arranged adjacent to the diaphragm mechanism in, for example, an interchangeable taking lens.

In the above structure, the first and second motors 30 and 31 are movably arranged in the annular space formed in the outer peripheral portion of the lens frame 6 of the shake prevention lens 8. The first and second movable members 36,
Since they are arranged at positions deviated in the circumferential direction from 37 in such a manner that their respective longitudinal directions have a positional relationship orthogonal to the optical axis I, despite the simple mechanical structure,
The DC motors 30 and 31 serving as drive means can be arranged without projecting to the outside, and the shake prevention mechanism portion 20 can be configured as a unit to reduce the space and cost of the mechanism portion 20. There are advantages.

Such an advantage is that the output shafts of the motors 30 and 31 are arranged so as to be oriented in the x-axis direction and the y-axis direction, respectively, and the rotational force thereof is first and First and second shafts 34, 35 serving as second converting means
Further, the first and second movable members 36 and 37 are configured to be converted into linear motions in the x-axis direction and the y-axis direction, respectively, so that they can be further exerted.

Further, in the above configuration, the shake prevention mechanism section 20 uses the case member composed of the substrate 21 and the lid body 22 in the annular space formed on the outer peripheral side of the lens frame 6 of the shake prevention lens 8. It is configured as a unit and is small in size, so that other complicated mechanical parts such as the lens shutter 12 illustrated in FIG. 7 can be arranged adjacent to each other. It can be used to exert an effect.

The drive load of the shake prevention lens 8 will be described. Explaining in the y-axis direction with reference to FIG. 8, the load torque T _fr when the movable member 37 is driven by rotating the shaft 35 (screw shaft) in the clockwise direction, that is, against the spring force P ₅₄ of the spring ₅₄ , is

[0039]

[Equation 1]

The load torque T _fl when driving the shaft 35 in the opposite counterclockwise direction, that is, in the direction of the spring force P ₅₄ of the spring 54 is

[0041]

[Equation 2]

It is represented by Where l is the lead of the screw (1
Feed amount per rotation), d_mIs the effective diameter of the screw, μ _mSplash
Friction coefficient of the threaded portion, α is the half angle of the thread, d_cIs the axis 35 and the axis
Average diameter of the contact portion with the receiving portion 21e, μ_cIs the axis 35 and the axis
It is the coefficient of friction of the contact portion with the receiving portion 21e.

As an example, the difference in load torque depending on the driving direction when the M3 coarse screw is used will be obtained. 1 = 0.5 mm, d _m = 2.675 mm, μ _m = 0.
3, α = 30 degrees, d _c = 1.3 mm, μ _c = 0.3, the following results are obtained.

[0044]

[Equation 3]

[0045]

[Equation 4]

As a result, the ratio of the load torque of the feed screw portion depending on the driving direction of the shake prevention lens 8 is:

[0047]

[Equation 5]

When driving against the spring 54, a torque that is almost twice as large as the opposite is required. Moreover, when the weight of the shake prevention lens 8 is taken into consideration, this ratio becomes even larger. When the force P _{54 of the} spring 54 is increased, the load torque ratio is the same and the load torques T _fr and T _fl are increased.
When the load torques T _fr and T _fl have large values with respect to the starting torque of the DC motor My, the drive speed of the shake prevention lens 8 varies depending on the drive direction, and it becomes impossible to perform accurate shake prevention control.

For example, the DC motor has a starting torque of 1 /
Driving a load of 3 to 1/2 is efficient. But,
As shown in FIG. 9A, the starting torque of the DC motor is set to Td.
And the load torque T _fr of the feed screw is 1 /
2. If the load torque T _fl is ¼ from the above calculation,
The speed ratio of the anti-shake lens 8 depending on the driving direction is 50:
It is clear that the value of 75 is large and the shake prevention control cannot be accurately performed.

Therefore, preferably, as shown in FIG. 9B, if the load torques T _fr and T _fl are set to 20% or less of the starting torque Td of the DC motor My in consideration of the gear ratio, the shake prevention lens is used. The ratio of the speed depending on the driving direction of 8 is about 10% or less, and accurate shake prevention control can be performed. The ratio of the load torques T _fr and T _fl can be adjusted by changing the lead l of the screw, and the ratio of the load torque can be reduced by reducing the value of the lead l. However, the screw needs to be specially processed, which increases the cost.

For this purpose, the starting torque Td of the DC motor My may be increased, but the DC motor becomes large and a space is required. The same applies to the X-axis direction. Therefore, it is necessary to set the force P _{54 of the} spring 54 to the necessary minimum.
The force P ₅₄ of the spring 54 will be described. The force of the spring 53 is P
₅₃ , the force of pressing the lens frame 6 against the four balls 70 to 73 by the two springs 51 and 52 is P _51, and the three forces P ₅₄ , P ₅₃ , and P ₅₁ are all the same and are represented by P. .

The load of the guide portion due to the balls when driving the shake prevention lens 8 in the plane orthogonal to the optical axis I is f _b = μ _b P = 0.2P of the bearing portions of the rollers 59, 60 and 61, 62. The load is the same in the x-axis direction and the y-axis direction, and f _r = μ _r P = 0.1P.

Anti-shake lens 8, lens frame 6, roller 5
9-62, the combined weight of the roller shaft 63 to 66 and is W, the relationship of _{P = W + (f b +} f r) = W + 0.3P a minimum force P of the spring it is necessary to support this,

[0054]

[Equation 6]

Therefore, the force of the springs 51 to 54 is 1. The weight of at least the shake-preventing lens 8 and the lens frame 6 is 1.
5 times is required. Preferably, in consideration of an acceleration of about 0.5 g (g) when driving the shake prevention lens 8,

[0056]

[Equation 7]

The force of the springs 51 to 54 should be at least twice the weight of the shake prevention lens 8 and the lens frame 6 together. Further, as described above, in order to make the load torque of the feed screw part less affected, for example, when the drive torque of the DC motor is 4 gr · cm (gram · cm) and the gear ratio is 30, the load torque T _fr
Is T _fr = 4 × 30 × 0.2 = 24 [gr · cm], and from the above-mentioned relationship of T _fr = 0.831P ₅₄ , P = 29 [gr] (grams), where the shake prevention lens is 8, the total weight W of the lens frame 6 and the like is 6 gr, and the relationship with the force P of the spring is

[0058]

[Equation 8]

The force of the springs 51 to 54 is preferably 5 times or less the total weight of the shake prevention lens 8, the lens frame 6 and the like. It is needless to say that a force smaller than this is preferable, and the gear ratio can be made smaller and the drive speed of the shake prevention lens can be made faster. In addition, since the starting torque of the DC motor can be made smaller, it becomes possible to use a smaller DC motor.

The present invention is not limited to the structure of the above-described embodiment, and the image blur prevention mechanism section 2 constituting the image blur prevention device.
It goes without saying that the shape, structure, etc. of each part including 0 can be appropriately modified and changed. For example, in the above-described embodiment, the reduction gear train (32, 33), which is the driving force transmission means from the driving force generation means (motors 30, 31) for the shake prevention optical system (the shake prevention lens 8; the lens frame member 6), is used. ,
Screw mechanism (34a, 35a;
36a, 37a) as a limiting means provided separately from the gear member 80x, which constitutes the second reduction gear train,
Although the case where 80y is used is shown, the present invention is not limited to this. That is, the limiting means is not limited to the above-mentioned gear member, but may be a gear mechanism or a cam,
A mechanical structure using a rack or the like may be used.

Further, in the above-described embodiment, the limiting gear 8
Grooves are provided on 0x and 80y, and a protrusion is provided on the bearing side.
These relationships can be changed appropriately, and various modifications of the shape and the like are conceivable. Further, in the above-described embodiment, the case where the present invention is applied to the camera having the lens shutter 12 has been described, but the present invention is not limited to this, and in order to prevent image blur due to camera shake in a conventionally known camera. Needless to say, the present invention can be applied to a shake prevention lens that shifts in a direction orthogonal to the optical axis I, and is not limited to the structure on the camera side.

Furthermore, the shake prevention device according to the present invention is not limited to the above-mentioned camera, but can be applied to various optical instruments, devices, etc. to exert its effect.

[0063]

As described in detail above, according to the present invention,
The shake prevention optical system is configured to urge the movement amount generating mechanism with an urging force in the range of 1.5 times to 5 times the weight of the shake preventing optical system, so that the force of the spring supporting the shake preventing lens is increased. The size can be set to an appropriate size, the shake-preventing lens can be reliably supported, and shake can be accurately prevented even when the shake-preventing lens is driven in all directions.

[Brief description of drawings]

FIG. 1 shows an embodiment of a shake prevention device according to the present invention,
FIG. 3 is a cross-sectional view of a main portion of a shake prevention mechanism portion that is a main portion in a lens barrel portion of a camera.

FIG. 2 is a view for explaining an example of a limiting means for limiting the movable range of the shake prevention lens, and FIGS.
FIG. 7 is an enlarged view of a main part of a portion indicated by arrows IIa and IIb in FIG.

3 is a sectional view taken along line III-III in FIG.

4 is a sectional view taken along line IV-IV in FIG.

5 is a sectional view taken along line VV of FIG.

FIG. 6 is an enlarged view of a main part for explaining the position detecting means of the shake prevention lens.

FIG. 7 is a schematic configuration diagram for explaining a schematic configuration of a camera with a lens shutter, to which the shake prevention device according to the present invention is applied.

FIG. 8 is a diagram for explaining a drive load of a shake prevention lens.

FIG. 9 is a diagram illustrating a speed difference _depending on a driving direction that load torques T _fr and T _fl give to a driving speed of a shake prevention lens.

[Explanation of symbols]

1 camera 2 photographing lens 4 first lens group 6 lens frame (lens frame member) 6a flange part 7 front lens group 8 rear lens group (anti-shake lens) 9 second lens group 11 third lens group 12 lens shutter 15 shutter drive Part 16 Image forming surface 20 Image blur prevention mechanism part 21 Substrate 21a Opening part 30 x-axis DC motor (driving means) 31 y-axis DC motor (driving means) 32 Driving force transmission gear train (reduction gear train) 32d gear 33 driving force transmission gear train (reduction gear train) 33d gear 34 first shaft (constituting a part of movement amount generation mechanism part) 34a male screw part 35 second shaft (part of movement amount generation mechanism part) 35a Male screw part 36 x Movable member on x-axis side 36a Female screw part 37 y Movable member on y-axis side 37a Female screw part 40x Disc with hole 40y Disc with hole 41x Photo 41y Photo interrupter 51 Spring 52 Spring 53 Spring 54 Spring 55 Guide member 56 Guide member 59 Roller 60 Roller 61 Roller 62 Roller 63 Roller shaft 64 Roller shaft 65 Roller shaft 66 Roller shaft 67 Retaining member 68 Retainer member 69 Retaining member 70 Ball 71 Ball 80 Limiting gear (gear member that constitutes the second reduction gear train serving as limiting means) I Optical axis of photographing lens system

Claims (4)

[Claims] 1. A shake prevention optical system that is moved to prevent image shake, a drive force generation device that generates a drive force for driving the shake prevention optical system, and a drive force of the drive force generation device. A movement amount generation mechanism section that generates a movement amount for moving the shake prevention optical system, and an urging mechanism section that urges the shake prevention optical system to the movement amount generation mechanism section. The shake prevention device is characterized in that the biasing mechanism unit biases the shake preventing optical system to the movement amount generating mechanism unit with a biasing force in the range of 1.5 times to 5 times the weight of the shake preventing optical system. 2. The shake preventing device according to claim 1, further comprising a guide for guiding the shake preventing optical system so that the shake preventing optical system can be moved in a plane substantially perpendicular to an optical axis of the shake preventing optical system. A mechanical part and a second part for urging the anti-shake optical system toward the guide mechanical part
The second urging mechanism section applies the anti-shake optical system to the guide mechanism with an urging force in the range of 1.5 times to 5 times the weight of the shake preventing optical system. A shake prevention device characterized by urging a part. 3. The shake prevention device according to claim 1, wherein the biasing mechanism portion has a weight of 1.5 times to 5 times the combined weight of the shake prevention optical system and a frame body holding the shake prevention optical system. The shake prevention device is characterized in that the shake prevention optical system is biased to the movement amount generation mechanism section by a biasing force in the range of. 4. The shake preventive device according to claim 2, wherein the second biasing mechanism portion has a weight of 1.5 to a combined weight of the shake preventive optical system and a frame body that holds the shake preventive optical system. A shake preventing device, characterized in that the shake preventing optical system is biased to the movement amount generating mechanism section by a biasing force in a range of 5 times.