JP2001194571A - Lens barrel incorporating camera shake correcting mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To miniaturize a driving mechanism for a correction lens and further to incorporate it in a lens barrel while restraining camera's getting large to the minimum. SOLUTION: A shutter driving mechanism or a diaphragm driving mechanism are arranged in the lens barrel and held in the half area of the cross section of the lens barrel, while the driving mechanism for the camera shake correction lens is arranged in the remaining half area of the cross section of the lens barrel. It is desirable to set a mechanism where the camera shake correction lens is driven by two driving levers capable of turning around a turning shaft as the driving mechanism for the camera shake correction lens.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens barrel having a built-in camera shake correction mechanism for use in an imaging device such as a camera.

[0002]

2. Description of the Related Art As an image pickup apparatus in which a camera shake correction mechanism is disposed in a lens barrel, a variable apex angle prism type in which a viscous fluid is sealed with two sheets of glass and the relative angle of the glass is changed by an actuator, or the like. A lens translation type in which a correction lens is translated in the X-axis and the Y-axis is conventionally known.

[0003] The camera shake correction mechanism of the lens parallel movement type has a problem that the lens barrel becomes large because it is necessary to move the correction lens in parallel to two orthogonal axes. Furthermore, in the lens parallel movement type, electromagnetic drive is used for thrust drive by a swing coil or lever drive by a motor, but the electromagnetic drive has a small driving force per unit volume, which also increases the size of the lens barrel. It is a factor to invite.

On the other hand, recent LS cameras (lens shutter cameras) have been reduced in size and increased in magnification, and the necessity for camera shake correction has been increasing more and more. However, the conventional camera shake correction mechanism is too large and cannot be applied to the LS camera.

[0005]

SUMMARY OF THE INVENTION Accordingly, the technical problem to be solved by the present invention is to reduce the size of the drive mechanism of the correction lens and to reduce the size of the drive mechanism in the lens barrel while minimizing the size of the camera. It is to be incorporated into.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to effectively solve the above-mentioned problems, and provides a lens barrel having the following features.

In the lens barrel according to the present invention, a shutter driving mechanism or an aperture driving mechanism which is disposed in the lens barrel and fits in a half area of the lens barrel cross section has a region corresponding to the other half of the lens barrel cross section. The drive mechanism of the camera shake correction lens is arranged in the inside. Therefore, it is possible to accommodate the correction lens driving mechanism in the lens barrel while minimizing the enlargement of the lens barrel.

The driving mechanism of the camera shake correction lens preferably has the following configuration. That is, a drive mechanism for driving the camera shake correction lens disposed in the lens barrel with two drive levers rotatable around a rotation axis, wherein each drive lever holds the camera shake correction lens. A lens holding shaft rotatably connected to the frame, wherein when one of the driving levers rotates, the camera shake correction lens is driven around the lens holding shaft of the other driving lever; The rotation axis and the lens holding axis are arranged on a straight line,
The "straight line connecting the lens holding axis of one drive lever and the optical axis center" is substantially orthogonal to the "straight line connecting the lens holding axis of the other drive lever and the optical axis center" (90 ° ± 30 °
Is preferred). With such a drive mechanism, the two drive levers can be arranged symmetrically with respect to a straight line passing through the optical axis in a plane perpendicular to the optical axis. Advantageously, they can be arranged to fit within half the area of the lens barrel cross section.
The drive mechanism of the camera shake correction lens includes two drive levers that can rotate the camera shake correction lens disposed in the lens barrel around a rotation axis, a shape memory alloy that drives the lever, May be provided.

In the present invention, each of the camera shake correction unit having the drive mechanism for the camera shake correction lens therein and the shutter unit or the aperture unit has a screw hole which is aligned with each other in a straight line. It is preferable that both units are fixed to the lens barrel using a screw member that is screwed into the aligned screw hole. According to this configuration, since the camera shake correction unit is directly fixed to the lens barrel, it is possible to minimize the cause of the tilt error of the correction lens due to the attachment to the lens barrel. Further, since one screw is provided for fixing both units, the number of screws used can be reduced, which is advantageous in terms of cost and precision control.

Each of the two drive levers is independent of each other by a shape memory alloy (SMA) that drives the lever in one direction around the rotation axis and a spring that biases the lever in the other direction. May be driven.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described by taking an LS camera (lens shutter camera) provided with a zoom lens barrel as an example. FIG. 1 is a perspective view of the LS camera 1 and shows that an acceleration sensor for detecting accelerations in X and Y directions is provided therein.

FIG. 2 illustrates the principle of driving the camera shake correction lens 10 disposed in the photographing optical system of the LS camera 1 in FIG. The correction lens 10 passes through the holding frame 11,
An X lever (X direction drive lever) 20 and a Y lever (Y direction drive lever) 30 are connected. That is, X lever 2
The lens holding shafts 21 and 31 of the 0 and Y levers 30 are rotatably inserted into holes provided in the protrusions 11a and 11b of the lens holding frame 11. When the X lever 20 rotates around the rotation axis 22, the correction lens 10 rotates about the lens holding axis 31 of the Y lever 30. Since the amount of rotation is very small, it can be regarded as a linear movement in the X-axis direction as indicated by arrow 200. When such a rotation is made, the distance between the two lens holding shafts 21 and 31 changes. To absorb the change, at least one of the holes provided in the protrusions 11a and 11b is removed. It is not a perfect circle but an ellipse.

The driving of the correction lens 10 in the Y-axis direction (arrow 300) is performed using the Y lever 30 in the same principle as described above. Further, the correction lens 10, as described later,
The unit base plate that defines the reference plane is pressed and urged by a spring, and moves only within the reference plane.

As described above, when the position control of the correction lens is performed by regarding the rotational movement as a linear movement, the "lens holding shaft"
It is desirable that a line connecting the optical axis 21 to the optical axis center C (the center of the correction lens 10) and a line connecting the lens holding axis 31 and the optical axis center C are orthogonal to each other. However, when strict orthogonality cannot be realized due to design problems or a demand for downsizing of the lens barrel, there is no practical problem if the angle is within the range of 90 ° ± 30 °.

FIG. 3 shows a control block diagram of the camera 1. The outline of the control procedure is as follows. The two acceleration sensors shown in FIG. 1 detect the direction and amount of movement of the camera due to camera shake. The current position A of the X lever 20 and the Y lever 30 is detected using a position sensor such as a photo reflector. Based on the “moving direction and moving amount”, the control unit calculates the correction lens position B after a predetermined time necessary for camera shake correction.
Is calculated. The position C of each lever corresponding to the correction lens position B is calculated using a previously stored “correction table (a table in which the correspondence between the position of each lever and the position of the correction lens is tabulated)” or an arithmetic expression. From the difference between the "current position A" of the lever and the "calculated lever position C", the current to be passed to the SMA is determined. That is, the SMA is deformed by the temperature rise due to this current.
(In the present invention, the wire-shaped SMA is contracted.) By using this, the X lever 20 and the Y lever 30 are moved to the position C as described later.

FIG. 4 is a plan view of a main part of the camera shake correction unit 100 constructed in accordance with the driving principle described with reference to FIG. 2, and FIG. 5 is a cross-sectional view of a main part along line 5-5 in FIG. The camera shake correction unit 100 is a unit in which the correction lens 10 and its driving mechanism are sandwiched between the base plate 50 and the top plate 60. Since the X lever 20 and the Y lever 30 have a mirror image relationship with each other, only the Y lever 30 will be described with reference to FIGS.

The Y lever 30 is held so as to be rotatable around a rotation shaft 32. A bias spring 40 having two arms 41 and 42 is inserted through the rotating shaft 32, and one arm
42 is in contact with the unit wall, and the other arm 41 is the lens holding frame
11 is in contact with the tapered portion 11a (see FIG. 5). Since the Y lever 30 is connected to the lens holding frame 11 via the lens holding shaft 31, the bias spring 40 eventually turns the Y lever 30 around the rotation shaft 32 in the counterclockwise direction in FIG. Will be energized.

The bias spring 40 has an arm 41
Is in contact with the tapered portion 11a of the lens holding frame 11,
At the same time when the Y lever 30 is urged in the counterclockwise direction, the lens holding frame 11 is also urged toward the base plate 50 located above in FIG. A pressing spring 62 disposed on a pedestal 61 provided on the top plate 60 also presses and biases the lens holding frame 11 toward the base plate 50. Therefore, the lens holding frame 11 is a bias spring for the Y lever.
The base plate 50 is pressed toward the base plate 50 by a total of three springs 40, an X lever bias spring (not shown), and a pressing spring 62.

The lens holding frame 11 abuts on the base plate 50 at the three abutting projections 13, so that the correction lens 10 held by the lens holding frame 11 is located within the reference plane defined by the base plate 50. Will always move. Since the lens holding frame 11 is biased toward the base plate 50 by three springs, it is possible to reliably prevent the correction lens 10 from coming off the reference plane.

A part of the Y lever 30 is folded downward in FIG. 5, and the folded portion 30a forms an SMA holding portion. One end of a wire-shaped SMA 70 is fixed to the SMA holding portion 30a using a screw member. On the other hand, a part of the top plate 60 located in the lower part in FIG. 5 is folded upward, and the SMA holding part 60a constituted by the folded part has
The other end of MA 70 is fixed. The SMA 70 stores a certain length for a certain temperature, and is configured to shrink to return to the certain length when the temperature rises due to a current flowing through itself. That is, when the temperature of the SMA 70 rises, the Y lever 30 is driven around the rotation shaft 32 in the clockwise direction in FIG.

As described above, the Y lever 30 is urged counterclockwise by the bias spring 40 and driven clockwise by the SMA 70. Therefore, the rotation of the Y-lever 30 can be controlled by controlling the current flowing through the SMA 70, whereby the correction lens 10 in the Y-axis direction can be controlled.
(See FIG. 2). Similarly, X lever
By controlling the rotation of 20, the X-axis direction of the correction lens 10
(See FIG. 2). Edge 33 of Y lever 30
Is a photo reflector 51 provided on the base plate 50 (see FIG. 4)
Constitute a detection end for detecting the position of the Y lever 30.

In the Y lever 30, “S
The ratio (lever ratio) of the “distance from the rotating shaft 32 to the lens holding shaft 31” to the “distance to the MA holding unit 30a” is 1.5 to
It is preferably 3. That is, a correction lens movement amount 1.5 to 3 times that of the SMA expansion / contraction amount is obtained.

Although not shown in FIG. 4 for simplicity, a bias spring similar to the above is provided for the X lever 20 as a matter of course. The rotation control and the position detection of the X lever 20 are performed in the same manner as in the case of the Y lever 30. As can be seen from FIG. 4, the SMA for the X lever 20 and the SMA for the Y lever 30 are three-dimensionally crossed in the lens barrel. This is because the SMA has a small amount of displacement, and therefore uses a SMA that is as long as possible in a limited space in the lens barrel.

As can be seen from FIG. 4, the bias spring 40 has two arms 41 and 42 extending substantially parallel to each other. Adopting such a configuration has the following advantages. That is, the unit wall and the lens holding frame 11
Since the reaction force acting on each arm 41 and 42 does not directly act on the rotating shaft 32, the rotating shaft can be smoothly rotated, and the rotating shaft falls down due to insufficient rigidity. Can be prevented.

In the present invention, the arrangement of the bias spring and the SMA is devised in order to prevent backlash when each drive lever rotates around the rotation axis. This will be described with reference to FIG. FIG. 6A shows only the Y lever 30 shown in FIG. As described above, the Y lever 30 is driven by the bias spring 40 and the SMA 70 to rotate about the rotation shaft 32. FIG. 6 (b)
F _SMA in the force vectors exerted SMA70 within Y lever 30, F _SP, the bias spring 40 is a vector force on Y lever 30, respectively. And
F _R is a vector indicating the force exerted by the rotating shaft 32 on the Y lever 30 as the reaction force. Numeral 32 'denotes a hole formed in the Y-lever 30 for inserting a rotating shaft, which is exaggerated for clarity.

As can be seen from FIG. 6B, when the magnitude of F _SMA and F _SP changes, the direction of F _R changes. When the direction of F _R changes, the position of the contact point between the drive shaft 32 and the hole 32 ′ changes. If this variation is large, the Y lever 30 will rattle with respect to the expansion and contraction of the SMA 70, and the accuracy of the camera shake correction will be reduced. If the angle between F _SMA and F _SP is zero, the movement of the contact point is also zero, and this is the most ideal. However, the angle formed between F _SMA and F _SP may not be zero due to design reasons such as preventing the lens barrel from becoming large. In practice, F _SMA and F _{SMA
If the} angle made by the _SP is suppressed to 120 ° or less, sufficient camera shake correction accuracy can be secured.

FIGS. 7 to 9 show the above-mentioned camera shake correction unit 10.
FIG. 9 is a cross-sectional view of relevant parts for explaining how 0 is actually arranged in the lens barrel. The configuration of the illustrated zoom lens barrel itself is generally known, and when the rotary barrel 120 rotates inside a fixed barrel 110 fixedly fixed to a camera body (not shown), the forward barrel 130 Is fed forward.

In the example of FIG. 7, the camera shake correction unit 100 and the shutter unit 200 are independently and individually fixed to the lens barrel using screws 131 and 132, respectively. By fixing each unit directly to the lens barrel, assembly errors can be minimized. In the example of FIG. 8, the camera shake correction unit 100 and the shutter unit 200 are integrated with a screw 133, and this is fixed in the lens barrel by fixing means (not shown).

FIG. 9 shows an example in which the camera shake correction unit 100 and the shutter unit 200 are directly fixed to the lens barrel. That is, the camera shake correction unit 100 and the shutter unit 200 are provided with screw holes 100a and 200a, respectively, which are aligned with each other in a straight line.
Each unit is directly fixed to the lens barrel by screwing one screw 134 into 0a and 200a. By directly fixing the correction lens to the lens barrel in this way, the inclination error factor of the correction lens can be minimized. In addition, since one screw is provided for fixing the two drive mechanisms, the total number of screws used can be reduced, which is advantageous not only in cost but also simplifies accuracy control. As shown in the drawing, only one place may be provided for such a joint stop, or several places may be provided.

The shutter unit 200 has a driving mechanism that can be accommodated in about a half area in the section of the lens barrel.
The drive mechanism of the camera shake correction unit 100 is arranged so as to fit in the other half area. That is, in FIG.
With respect to the line A that divides the lens barrel section into halves, the drive mechanism of the shutter unit 200 is located in the area S located on the opposite side to the camera shake correction lens drive mechanism. This makes it possible to accommodate the camera shake correction unit 100 in the lens barrel while minimizing the size of the lens barrel to a minimum.

As described above, the photo-reflector 51 for detecting the position of the Y-lever 30 is provided with a camera shake correction unit.
It is attached to 100 base plates 50 (see FIG. 5). As shown in FIGS. 10 and 11, the photo reflector 51 is electrically connected to a control system on the camera body side through a flexible board 101 wired from the outside of the camera shake correction unit 100. FIG. 10 is a cross-sectional view of a main part for schematically explaining this, and FIG. 11 is a schematic explanatory view showing a circle B in FIG. 10 in an enlarged manner.

The flexible board 101 arranged along the outer surface of the base plate 50 of the camera shake correction unit 100 is efficiently arranged in the lens barrel so as to extend in the optical axis direction. By wiring the flexible board 101 outside the unit 100, the board 101 can be shared with the flexible board for the shutter unit 200 as in the example shown in the figure. Furthermore, it is also possible to prevent the flexible substrate 101 from interfering with each of the drive levers 20 and 30 provided in the unit. 7 to 11 illustrate the positional relationship between the camera shake correction unit 100 and the shutter unit 200 (in which the shutter mechanism and its driving mechanism are unitized). (Not shown).

In the illustrated embodiment, each drive lever
20 and 30 are biased by a shape memory alloy in one rotation direction and biased by a bias spring in the other rotation direction. In the present invention, instead, it is also possible to urge both rotation directions using a shape memory alloy.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an LS camera according to an embodiment of the present invention.

FIG. 2 is a schematic diagram illustrating a driving principle of a correction lens in the camera shake correction mechanism of the camera in FIG.

FIG. 3 is a control block diagram of the camera in FIG. 1;

FIG. 4 is a main part plan view for explaining a driving mechanism of the present invention to which the principle of FIG. 2 is applied.

FIG. 5 is a sectional view taken along line 5-5 in FIG. 4;

FIG. 6 is an explanatory diagram showing the Y lever 30 in FIG. 4 taken out therefrom.

FIG. 7 is a cross-sectional view of a main part showing an example of disposing the camera shake correction unit in the lens barrel according to the present invention.

FIG. 8 is a cross-sectional view of a main part showing an example of disposing the camera shake correction unit in the lens barrel according to the present invention.

FIG. 9 is a cross-sectional view of a main part showing an example of disposing the camera shake correction unit in the lens barrel according to the present invention.

FIG. 10 is a sectional view of a main part showing an example of wiring of a flexible substrate to a camera shake correction unit according to the present invention.

11 is a partially enlarged view of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 LS camera 10 Camera shake correction lens 11 Holding frame 11a, 11b Projection 13 Contact projection 20 X direction drive lever 21 Lens holding shaft 22 Rotation axis 30 Y direction drive lever 30a SMA holding part 31 Lens holding axis 32 Rotation axis 32 'Rotating shaft insertion hole 33 Detecting end 40 Bias spring 41, 42 Arm 50 Base plate 51 Photoreflector 60 Top plate 60a SMA holder 61 Pedestal 62 Press spring 70 SMA 100 Camera shake correction unit 100a Screw hole 101 Flexible Substrate 110 Fixed cylinder 120 Rotating cylinder 130 Forward cylinder 131, 132, 133, 134 Screw 200 Shutter unit 200a Screw hole

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoshihiro Hara 2-3-113 Azuchicho, Chuo-ku, Osaka-shi, Osaka Inside Osaka International Building Minolta Co., Ltd. (72) Inventor Akira Kosaka Azuchi-cho, Chuo-ku, Osaka-shi, Osaka 2-3-1-3 Osaka International Building Minolta Co., Ltd. F-term (reference) 2H044 AE10 BD01

Claims (5)

[Claims] 1. A camera shake correction lens provided in a remaining half area of a lens barrel section for a shutter drive mechanism or an aperture drive mechanism disposed in a lens barrel and accommodated in a half area of the lens barrel section. Characterized by the arrangement of the drive mechanism,
Lens barrel with built-in camera shake correction mechanism. 2. A drive mechanism for driving a camera shake correction lens, comprising: two drive levers capable of rotating a camera shake correction lens disposed in a lens barrel around a rotation axis; and a shape for driving the lever. The lens barrel with a built-in camera shake correction mechanism according to claim 1, comprising a memory alloy. 3. A drive mechanism for driving the camera shake correction lens, wherein the camera shake correction lens disposed in the lens barrel is driven by two drive levers rotatable around a rotation axis. Each drive lever has a lens holding shaft rotatably connected to the holding frame of the camera shake correction lens, and when one of the drive levers rotates, the other drive lever rotates about the lens holding shaft of the other drive lever. The camera shake correction lens is driven, the rotation axis of both drive levers and the lens holding axis are arranged on a straight line, and the straight line connecting the lens holding axis of one drive lever and the optical axis center is the other. 2. The lens barrel with a built-in camera shake correction mechanism according to claim 1, wherein a straight line connecting the lens holding axis of the drive lever and the center of the optical axis is substantially orthogonal to each other. 4. A camera shake correction unit having a drive mechanism for the camera shake correction lens therein, and a shutter unit or an aperture unit each having a screw hole that aligns with each other in a straight line with each other. The lens barrel with a built-in camera shake correction mechanism according to any one of claims 1 to 3, wherein both drive mechanisms are fixed to the lens barrel using a screw member screwed into the hole. 5. Each of the two drive levers is independent of each other by a shape memory alloy that drives the lever in one direction around the rotation axis and a spring that biases the lever in the other direction. The lens barrel with a built-in camera shake correction mechanism according to claim 2, wherein the lens barrel is driven.