JP2008244534A - Camera shake correction apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a camera shake correction apparatus for a camera capable of preventing the damage or destruction of a correction lens due to an impact. <P>SOLUTION: The camera shake correction apparatus comprises: a sensor mounted on the camera for detecting the acceleration of the camera generated by a hand movement during a photographing operation; a correction lens 3 mounted on a barrel of the camera so as to correct for the hand movement; an actuator for driving the correction lens 3; and a controller for obtaining drive data including the driving direction and driving speed of the correction lens 3 on the basis of the acceleration of the camera detected by the sensor and controlling the actuator on the basis of the obtained drive data. When the acceleration detected by the sensor exceeds a prescribed threshold, the controller controls the actuator and abuts the correction lens 3 to a stopper member ST. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a camera shake correction device for correcting disturbance of a captured image (hereinafter, this phenomenon may be referred to as camera shake) caused by camera shake during a camera shooting operation.

2. Description of the Related Art Conventionally, camera shake correction devices for cameras are known, and for example, disclosed in Patent Document 1. This camera shake correction apparatus includes a correction lens, an actuator, a controller, and a lamp. The correction lens is incorporated in the lens barrel in order to cancel image blur on the imaging plane due to camera shake. The actuator moves the correction lens in a direction in which the subject image formed by the photographing optical system incorporated in the lens barrel does not shake with respect to the imaging plane. The controller determines whether or not a camera shake that exceeds the range that can be corrected by the correction lens has occurred. Further, the controller controls the actuator so as to stop the movement of the correction lens when it is determined that the camera shake exceeding the range that can be corrected by the correction lens has occurred. The lamp is controlled to be turned on by the controller and notifies that a camera shake exceeding the correctable range has occurred.
Japanese Patent Application Laid-Open No. 07-261230

  In the case of a camera shake that exceeds the range that can be corrected by the correction lens, the conventional camera shake correction device lights this lamp to notify the fact. In this case, camera shake correction is not actually performed because it exceeds the range. In an actual use state, not only a relatively light acceleration such as camera shake, but also a large acceleration may be applied due to an impact or a drop. A conventional camera shake correction device incorporates an acceleration sensor, detects acceleration applied to the camera, and drives a correction lens to perform camera shake correction. The conventional camera shake correction device has a function of lighting a warning lamp when excessive camera shake occurs. However, there may be an excessive impact on the camera due to careless handling. In this case, the correction lens that is electrically held at the neutral position may collide with the lens holding mechanism due to an impact and may be damaged or destroyed. Although the conventional camera shake correction device includes an acceleration sensor, the risk of damage or destruction of the correction lens due to impact is not taken into consideration, and is a problem to be solved.

  In view of the above-described problems of the conventional technology, an object of the present invention is to provide a camera shake correction device for a camera that can prevent damage or destruction of a correction lens due to impact. In order to achieve this purpose, the following measures were taken. That is, the present invention is a sensor mounted on a camera that detects camera acceleration caused by camera shake during a shooting operation, a correction lens mounted on a camera barrel for correcting camera shake, and driving the correction lens. And a controller that obtains drive data including the drive direction and speed of the correction lens based on the acceleration of the camera detected by the sensor and controls the actuator based on the obtained drive data. In the correction apparatus, the controller controls the actuator to apply the correction lens to the stopper member when the acceleration detected by the sensor exceeds a predetermined threshold value.

  Preferably, the stopper member includes a cushioning material at a portion in contact with the correction lens. The controller applies the correction lens to a stopper member positioned in a direction opposite to the detected acceleration.

  According to the present invention, when the acceleration detected by the sensor exceeds a predetermined threshold value, the controller controls the actuator to apply the correction lens to the stopper member. With this configuration, even when an excessive impact is applied to the camera due to careless handling, etc., this is detected quickly and the correction lens is applied to the stopper member. There is no risk of damage or destruction of the correction lens. In this way, the present invention provides a camera that is resistant to impact, vibration, drop, etc. by detecting the impact when the camera is impacted and mechanically fixing the correction lens so that it does not receive extra external force. I can do it.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic view showing a camera barrel incorporating a camera shake correction apparatus according to the present invention. The basic principle of the camera shake correction apparatus for a camera according to the present invention will be described with reference to this schematic diagram. As shown in FIG. 2A, a mirror copper for a camera is composed of an AF lens 1, a zoom lens 2, and a camera shake correction lens 3 mounted therebetween, and is arranged along the optical axis. Light emitted from the subject passes through the AF lens 1, the camera shake correction lens 3, and the zoom lens 2 as indicated by arrows, and forms an inverted image on the imaging surface. This imaging surface is a light receiving surface of an imaging device in the case of a digital camera, and a film in the case of a silver salt camera.

  (B) represents a state in which camera shake occurs during the shooting operation. If there is camera shake, the light emitted from the subject deviates from the optical axis direction of the mirror copper, so that the inverted image formed on the imaging surface deviates from the original arrival point shown in FIG. As shown by the arrow, this shift becomes a camera shake. As a result, the image of the inverted image appearing during the exposure operation is picked up, and the image quality is disturbed.

  (C) shows the result of driving the camera shake correction lens 3 in order to correct this camera shake. The camera shake correction device obtains drive data including the drive direction and drive speed of the camera shake correction lens 3 based on camera movement information detected in advance by an acceleration sensor. The controller of the camera shake correction apparatus controls the actuator based on the obtained drive data and shifts the camera shake correction lens 3 to remove the influence of camera shake. As shown in the figure, by shifting the camera shake correction lens 3 in a predetermined direction, the light emitted from the subject is bent so that the light reaches the original arrival point. As a result, even if there is camera shake during the exposure operation, the position of the inverted image on the imaging surface does not shift, and a clear image can be obtained.

  FIG. 2 is a block diagram showing the overall configuration of the camera shake correction apparatus according to the present invention. As shown in the figure, the camera shake correction apparatus according to the present invention basically includes an acceleration sensor 4, a correction lens 3, an actuator 5, and a controller 6. The acceleration sensor 4 is attached to the camera and detects the movement of the camera caused by camera shake during the photographing operation. In the illustrated embodiment, the acceleration sensor includes a pair of gyro sensors, and detects yawing components and pitching components, which are angular velocity changes in directions orthogonal to each other, as camera movement information. When an external force (acceleration) is applied to the camera, the angular velocity component changes, and the gyro sensor 4 detects this. Therefore, the gyro sensor 4 can detect the acceleration applied to the camera. The detected yawing information is input to the controller 6 through the first bandpass filter (BPF1). The pitching information is also input to the controller 6 through the second bandpass filter (BPF2).

  The correction lens 3 is mounted on the mirror copper of the camera in order to correct camera shake. In the illustrated example, the correction lens 3 is attached to a mirror copper (not shown) of the camera while being held on the substrate 10. The actuator 5 drives the correction lens 3 mounted on the substrate 10. In the illustrated example, the actuator 5 is divided into two parts. The left actuator 5 is composed of a coil mounted on the substrate 10 and a magnet fixedly disposed below the coil. The right actuator 5 is similarly composed of a coil mounted on the substrate 10 and a magnet fixedly disposed below the coil. In the left and right actuators 5, the magnetizing directions of the magnets are orthogonal. Thereby, the drive directions of the left and right actuators 5 are orthogonal to each other. As a result, the correction lens 3 can be driven in a two-dimensional direction by the pair of actuators 5. The controller 6 obtains drive data including the drive direction and drive speed of the correction lens 3 based on the camera movement information detected by the sensor 4, and controls the actuator 5 based on the obtained drive data. In the illustrated example, the controller 6 is composed of a 32-bit 20 MHz microcomputer (microcomputer), and drives the actuator 5 via a driver IC 7 for driving a correction lens. A Hall element is attached on the substrate 10 constituting the actuator 5 and fed back to the controller 6 via the position detection servo circuit 8.

  With continued reference to FIG. 2, the electrical operation of the camera shake correction apparatus will be described in detail. As described above, a pair of Hall elements is attached to the substrate 10 on which the correction lens 3 is mounted. A magnet is fixedly installed on the back side of the substrate 10 on which the Hall element and the coil are mounted. When the correction lens 3 is driven, the Hall elements move on the corresponding magnets, so that an output is generated. The Hall element is set so that a linear output is generated by the movement of the correction lens 3. Here, the position detection servo circuit 8 and the driver IC 7 are connected to the controller 6 to form a feedback loop. With this configuration, current is passed through the pair of coils constituting the actuator 5 via the driver IC 7 so that the output of the Hall element becomes the target voltage set by the controller 6. As a result, the pair of coils can move in the vertical and horizontal directions as indicated by arrows, and the control thereof is determined by the output voltage supplied from the controller 6 to the driver IC 7. Therefore, the camera shake correction device stops at the position where the correction lens 3 is set with the voltage output by the controller 6. In order to confirm the position, the controller 6 monitors the Hall voltage output from the position detection servo circuit 8.

  FIG. 3 is a plan view and a side view showing a specific configuration around the actuator of the camera shake correction apparatus shown in FIG. As shown in the figure, the camera shake correction apparatus is assembled using a base plate 40, and a correction lens 3 is mounted thereon via an actuator. The base plate 40 is basically a disk type and is mounted in the lens barrel in a state orthogonal to the optical axis of the camera. An x magnet 51 and a y magnet 61 are embedded in the base plate 40. The pair of x magnets and y magnets constitute a part of the actuator and apply a magnetic field to the Hall sensor (Hall element).

  An x (left and right) stage 50 is mounted on the base plate 40. The x stage 50 is supported on the base plate 40 by a pair of x1 axis and x2 axis, and is movable in the x direction (left and right direction in the drawing).

  An x hall sensor 53 is attached to the x stage 50 so as to face the x magnet 51. The x hall sensor 53 relatively moves on the x magnet 51 as the x stage 50 moves. At this time, since a change occurs in the magnetic flux crossing the x hall sensor 53, the x hall sensor 53 detects the movement of the x stage 50 along the x axis direction.

  An x coil 52 is also arranged on the x stage 50 so as to face the x magnet 51. The x coil 52 is combined with the x magnet 51 to constitute an actuator, and drives the x stage 50 in the x-axis direction. Specifically, when the x coil 52 is energized, a magnetic flux is generated, and a magnetic force appears between the x magnet 51 and the x stage 50 moves in the x-axis direction.

  A y (upper and lower) stage 60 is mounted on the x stage 50. Specifically, the y stage 60 is slidably attached to a pair of y1 axis and y2 axis attached to the x stage 50. As a result, the y stage 60 is movable in the vertical direction (y-axis direction). The base plate 40, the x stage 50, and the y stage 60 described above correspond to the substrate 10 shown in FIG.

  A y hall sensor 63 is mounted on the y stage 60 and is disposed opposite to the y magnet 61 on the base plate 40 side. Thereby, the y Hall sensor 63 can detect the position of the y stage 60 along the y-axis direction. In addition, a y coil 62 is mounted on the y stage 60 and is disposed opposite to the y magnet 61 on the base plate 40 side. The pair of y coils 62 and the y magnets 61 constitute an actuator, and the y stage 60 can move along the y axis direction by energizing the y coils 62.

  The correction lens 3 is mounted on the y stage 60. As described above, the y stage 60 is attached to the x stage 50 by the y1 axis and the y2 axis, and is movable in the y direction. The x stage 50 is attached to the base plate 40 by the x1 axis and the x2 axis, and is movable in the x direction. A y coil 62 that is an actuator and a y hall sensor 63 that is a position sensor are attached to the y stage 60. Similarly, an x coil 52 as an actuator and an x hall sensor 53 as a position sensor are attached to the x stage 50. A pair of x magnets 51 and y magnets 61 are incorporated in the base plate 40. By energizing the x coil 52, the correction lens 3 can be moved to a predetermined speed and a predetermined position in the x-axis direction (left-right direction). Further, by energizing the y coil 62, the correction lens 3 can be moved to a predetermined position at a predetermined speed along the y direction (vertical direction). The camera shake correction is performed by driving the correction lens 3 in the x-axis direction and the y-axis direction so as to cancel the camera shake detected by the camera shake sensor.

  At this time, the lens position is detected in order to servo-control the drive of the correction lens 3. The y direction position of the correction lens 3 is detected by the y hall sensor 63, and the x direction position is detected by the x hall sensor 53. A y Hall sensor 63 mounted on the y stage 60 monitors the position of the correction lens 3 in the y direction by detecting a change in magnetic flux density of the y magnet 61 during movement. Similarly, the x Hall sensor 53 monitors the position of the correction lens 3 in the x direction by detecting a change in magnetic flux density generated by the x magnet 51 while moving while being mounted on the x stage 50.

  As a feature of the present invention, the stopper ST is attached to at least one x1 axis of the pair of axes that support the x stage 50. Similarly, the stopper member ST is provided on at least one y2 axis of the pair of axes that support the y stage 60. The controller of the camera shake correction device controls the actuator to apply the correction lens 3 to the stopper member ST when the acceleration detected by the acceleration sensor exceeds a predetermined threshold value. The stopper member ST is made of a cushioning material disposed at a portion that contacts the correction lens 3. The controller applies the correction lens 3 to the stopper member ST located in the direction opposite to the detected acceleration. As described above, according to the present invention, when an impact is applied to the camera, it is detected and the correction lens 3 is mechanically fixed, so that an extra external force is not applied, and a mechanism that is strong against impact, vibration, drop, etc. A mechanism is obtained.

  FIG. 4 is a timing chart for explaining the operation of the camera shake correction apparatus according to the present invention shown in FIGS. This timing chart represents the movement of the correction lens in accordance with the output change of the gyro sensor. The gyro sensor outputs a signal representing a change (acceleration) in angular velocity applied to the camera with the passage of time, and the direction of acceleration is represented by a symbol of ±. Together with this, the time axis t represents the movement amount and movement direction of the correction lens. The correction lens is normally maintained at the neutral position (zero), and is driven in the + direction or the − direction with reference to this. A mechanical stopper in the + direction is arranged at the limit in the + direction, and a mechanical stopper is arranged in the limit in the − direction.

  As shown in the timing chart of FIG. 4, during normal times when camera shake correction is not yet performed, the correction lens is held at the neutral position by the actuator even if the output of the gyro sensor fluctuates. However, even in this case, the gyro sensor mounted on the camera is operating and the detection output is constantly monitored.

  Subsequently, when a photo opportunity occurs, camera shake correction starts, and the output of the gyro sensor is amplified by the BPF and then supplied to the controller 6. The controller controls the actuator in accordance with the output from the gyro sensor, and drives the correction lens in a direction that cancels camera shake. When the shutter operation (imaging operation) of the camera is completed, the camera shake correction mode is canceled and the correction lens returns to the neutral position.

  Thereafter, when a sudden acceleration is applied to the camera due to an impact or a drop, a detection output exceeding the threshold value Vth is generated from the gyro sensor. In this case, the controller immediately gives an instruction to the actuator and applies the correction lens to the stopper member. Thereafter, when a predetermined set time elapses, the correction lens returns to the intermediate position. In this way, the correction lens can be prevented from being destroyed by impact.

  FIG. 5 is a circuit diagram showing a control system of the camera shake correction apparatus according to the present invention. As shown in the drawing, the circuit of the camera shake correction apparatus is divided into an x system that performs control in the x direction and a y system that performs control along the y direction. In FIG. 5, the x system and the y system are distinguished from each other by adding a subscript x or y to the reference number of each circuit element.

  The camera shake correction apparatus includes a camera x, y angular velocity detection circuit 104a that receives an input from a camera shake sensor (not shown). A drive arithmetic circuit 109 is connected to the camera x and y angular velocity detection circuit 104a. The drive arithmetic circuit 109 is composed of a CPU or a microcomputer (microcomputer), and constitutes a control unit of a camera shake correction device or a main part of a controller. A storage circuit 107 is connected to the drive arithmetic circuit 109 and stores various data necessary for controlling the camera shake correction apparatus.

  The drive arithmetic circuit 109 is connected to a servo circuit divided into a y system and an x system. First, the y servo system includes a y drive instruction circuit 110y, a y differential circuit 111y, a y amplifier circuit 112y, a y actuator drive circuit 113y, a y coil 62, a y hall sensor 63, and a y detection circuit 114y. . Although not shown, a magnet is disposed opposite to the y coil 62. The y actuator drive circuit 113y energizes the y coil 62 to drive the correction lens in the y direction. The y Hall sensor 63 is also disposed opposite to the magnet embedded in the base plate, and outputs a detection output to the y detection circuit 114y side according to the movement of the correction lens along the y direction.

  In such a configuration, the drive arithmetic circuit 109 instructs the y drive instruction circuit 110y to move the correction lens along the y direction. The y differential circuit 111y supplies a drive signal to the y actuator drive circuit 113y until the y-direction movement amount output from the y drive instruction circuit 110y matches the detection result output from the y detection circuit 114y. Actually, this drive signal is supplied to the y actuator drive circuit 113y via the y amplifier circuit 112y. With such a servo circuit or feedback circuit, the correction lens is driven in the y direction until the position in the y direction calculated by the drive arithmetic circuit 109 is reached.

  The x servo system has the same configuration, and includes an x drive instruction circuit 110x, an x differential circuit 111x, an x amplifier circuit 112x, an x actuator drive circuit 113x, an x coil 52, an x hall sensor 53, and an x detection circuit 114x. It is configured. The drive arithmetic circuit 109 calculates the correction lens movement amount in the x direction based on the output from the camera x, y angular velocity detection circuit 104a and the data stored in the storage circuit 107, and issues an instruction corresponding to the x drive instruction circuit 110x. . The x differential circuit 111x supplies a drive signal to the x actuator drive circuit 113x through the x amplifier circuit 112x until the output from the x drive instruction circuit 110x side matches the output from the x detection circuit 114x side. The x coil 52 is energized from the x actuator drive circuit 113x, and moves the x stage along the x direction. The x Hall sensor 53 monitors the position of the x stage, and the x detection circuit 114x feeds back the monitoring result to the x differential circuit 111x.

  As a characteristic item, the detection output comparison circuit 108 outputs to the drive arithmetic circuit 109. When a sudden acceleration is applied to the camera, a large output of the gyro sensor is generated and input to the drive arithmetic circuit 109 via the camera x and y angular velocity detection circuit 104a. At this time, the detection output comparison circuit 108 compares the threshold value Vth stored in advance with the output from the angular velocity detection circuit 104a, and when the detection result is larger than the threshold value, immediately notifies the drive arithmetic circuit 109 of the comparison result. The drive arithmetic circuit 109 outputs a signal for applying the correction lens to the stopper member to one or both of the y drive instruction circuit 110y and the x drive instruction circuit 110x according to the detected direction of the angular velocity. In response to this, the y actuator drive circuit 113y or the x actuator drive circuit 113x operates to bring the correction lens into contact with the stopper member. After that, when the set time has elapsed, the drive arithmetic circuit 109 issues a release command and returns the correction lens to the neutral position.

It is a schematic diagram which shows the principle of the camera-shake correction apparatus concerning this invention. 1 is a block diagram showing an overall configuration of a camera shake correction apparatus according to the present invention. FIG. 2 is a schematic plan view and a side view showing the periphery of the actuator of the camera shake correction apparatus according to the present invention. It is a timing chart with which it uses for description of operation | movement of the camera-shake correction apparatus concerning this invention. It is a circuit diagram which shows the control system of the camera-shake correction apparatus concerning this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 ... Camera shake correction lens, 4 ... Gyro sensor, 5 ... Actuator, 6 ... Controller, ST ... Stopper member

Claims (3)

A sensor that is mounted on the camera and detects camera acceleration caused by camera shake during shooting operation;
To correct camera shake, a correction lens mounted on the camera barrel,
An actuator for driving the correction lens;
In a camera shake correction apparatus comprising: a drive data including a driving direction and a driving speed of a correction lens based on camera acceleration detected by the sensor; and a controller that controls the actuator based on the obtained driving data.
When the acceleration detected by the sensor exceeds a predetermined threshold value, the controller controls the actuator to apply the correction lens to the stopper member.   The camera shake correction device according to claim 1, wherein the stopper member includes a cushioning material at a portion in contact with the correction lens.   The camera shake correction apparatus according to claim 1, wherein the controller applies the correction lens to a stopper member positioned in a direction opposite to the detected acceleration.

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