JP2008216289A - Camera shake correcting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce load on a mechanical mechanism by preventing sudden movement of a camera shake correction lens during the turning on of the power source of a camera. <P>SOLUTION: Based on information about a camera movement detected by a camera shake sensor 4, a controller 6 obtains drive data including an amount of movement of the correction lens 3. Also, based on drive data obtained by monitoring position information output from the position sensor 8, the controller 6 controls an actuator 5. When shifting takes place from a quiescent state to an operating state, the controller 6 first supplies power to a position sensor 8 and captures position information representing the current position of the correction lens 3. Next, based on the captured position information, the current position is set as a target position, and the actuator 5 is started to hold the correction lens 3 in the current position. Subsequently, a predetermined initial position is reset to a target position, the actuator 5 is controlled, and the correction lens 3 is conveyed from the current position to the initial position at a constant speed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

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

2. Description of the Related Art Conventionally, a camera shake correction device incorporated in a camera is known. A conventional camera shake correction device includes a camera shake sensor, a correction lens, an actuator, a position sensor, and a controller (control unit). The camera shake sensor is composed of a gyro sensor, for example, and is attached to the camera to detect camera movement caused by camera shake during shooting operation. The correction lens is attached to the lens barrel of the camera in order to correct camera shake. The position sensor is composed of, for example, a Hall sensor, detects the position of the correction lens, and outputs corresponding position information. The actuator is composed of a combination of a coil and a magnet, for example, and drives the correction lens in a plane intersecting the optical axis of the lens barrel. The controller (control unit) obtains drive data including the movement amount of the correction lens based on the movement information of the camera detected by the camera shake sensor, and based on the drive data while monitoring the position information output from the position sensor. Control the actuator. With this configuration, even when the camera moves due to a shutter operation during shooting operation, the correction lens is driven to correct camera shake so that the captured image is not disturbed.
Japanese Patent Laid-Open No. 4-21831

  The power is off when the camera is not in use. That is, there is no power supply when the system is in hibernation. At this time, the correction lens in the lens barrel is not regulated and is in a floating state. Therefore, the current position of the correction lens is not always constant in the resting state.

  When the power is turned on to use the camera, the system shifts from the hibernation state to the operation state. At the time of activation, the correction lens is initialized to a predetermined position (home position) (hereinafter, this predetermined position may be referred to as an initial position in the present specification). When power is supplied to the system, the position sensor works to detect the current position of the correction lens. The current position is not necessarily constant and often deviates from the initial position. The system controller (controller) activates the actuator to quickly move the correction lens from the current position to the initial position. As a result, the lens is rapidly driven. Typically, in order to stabilize the correction lens by sending it to the initial position in a short time after the power is turned on until the monitor screen turns on, the correction lens is driven rapidly. For this reason, a large load is applied to the mechanism that supports the correction lens when the power is turned on. This load is generated every time the camera is turned on. In order to ensure the durability of the camera, the mechanical mechanism of the correction lens has to be designed to withstand this load. For this reason, there is a problem that the mechanical mechanism is excessively costly.

  The camera shake correction apparatus disclosed in Patent Document 1 is devised so that a sudden load is not applied to the mechanical mechanism of the correction lens when the power is turned on. When the camera is turned on, a built-in timer automatically measures a predetermined time. Within this measurement time, the correction lens is driven and transferred from the current position to the initial position. Since the timer setting time is relatively long, the correction lens can be slowly sent to the home position. However, even if the current position and the initial position are very close, it takes time for initialization by the set time of the timer. Setting the time with the timer in this way may unnecessarily increase the waiting time.

  In view of the above-described problems of the prior art, the present invention reduces the burden on the mechanical mechanism by preventing a sudden movement of the correction lens when the power is turned on, and quickly initializes the correction lens without wasting unnecessary waiting time. An object of the present invention is to provide an image stabilization device that can move to a position. In order to achieve this purpose, the following measures were taken. That is, the present invention is a camera shake sensor that is mounted on a camera and detects camera movement caused by camera shake during a shooting operation, a correction lens that is mounted on a camera barrel for correcting camera shake, and an optical axis of the lens barrel. An actuator for driving the correction lens in a plane intersecting with the position, a position sensor for detecting the position of the correction lens and outputting corresponding position information, and movement information of the camera detected by the camera shake sensor. A camera shake correction apparatus comprising: a drive unit including a correction lens movement amount based on the controller; and a controller that controls the actuator based on the obtained drive data while monitoring position information output from the position sensor. When the control unit shifts from the resting state to the operating state, the control unit first energizes the position sensor to indicate the current position of the correction lens. Next, based on the acquired position information, the current position is set as a target position, the actuator is activated to hold the correction lens at the current position, and then a predetermined initial position is set as the target position. The actuator is controlled again and the correction lens is transferred from the current position to the initial position.

  Preferably, the control unit controls the actuator to move the correction lens from a current position to an initial position at a constant speed.

  According to the present invention, when shifting from the resting state to the operating state, the current position of the correction lens is first detected. The actuator is activated with the current position as a target position. As a result, the correction lens can be reliably held and fixed at the current position. Subsequently, the initial position (home position) is reset to the target position, and the correction lens is transferred from the current position to the initial position. This transfer can be performed while the controller (control unit) controls the actuator based on the current position and the initial position. Therefore, the rapid movement of the correction lens does not occur unlike the conventional case, and the burden on the mechanical mechanism can be reduced. Conventionally, since the current position is unknown and activation is performed toward the home position, a very rapid force is applied to the correction lens depending on the positional relationship. On the other hand, when the detected current position is close to the initial position, the controller can quickly move the correction lens to the initial position in accordance with the positional relationship between the two. In other words, if the current position of the correction lens before energization is close to the initial setting position, the correction lens can be stabilized in a short time because there is almost no moving amount. It is not necessary to wait for the timer set time regardless of the current position as in the past.

  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, the camera lens barrel includes 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. When there is a camera shake, light emitted from the subject deviates from the optical axis direction of the lens barrel, 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 a camera shake 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 an embodiment of a 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 a camera shake sensor 4, a correction lens 3, an actuator 5, and a controller 6. The camera shake sensor 4 is attached to the camera, and detects the movement of the camera caused by camera shake during a shooting operation. In the illustrated embodiment, the camera shake sensor 4 includes a pair of gyro sensors and detects a yawing component and a pitching component as camera movement information. 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 attached to the lens barrel of the camera in order to correct camera shake. In the illustrated example, the correction lens 3 is mounted on a camera barrel (not shown) while being held by 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 orthogonal to the optical axis 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 camera shake 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 the output is fed back to the controller 6 via the position detection 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 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 apparatus according to the present invention 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 circuit 8.

  As is clear from the above description, the HaLL element functions as a position sensor, and detects the position of the correction lens 3 and outputs corresponding position information. The output of the Hall element is amplified by the position detection circuit 8 and input to the controller 6 and the driver IC 7. The driver IC 7 energizes the coil of the actuator 5 according to the difference between the current position of the correction lens 3 input from the position detection circuit 8 and the target position input from the controller 6, and drives the correction lens 3 to the target position. To do. Accordingly, the driver IC 7 energizes the coil of the actuator 5 until the current position of the correction lens 3 supplied from the position detection circuit 8 reaches the target position of the correction lens 3 indicated by the controller 6. Preferably, the driver IC 7 controls the energization amount so that the correction lens 3 moves at a constant speed from the current position to the target position.

  The controller 6 constitutes a control unit of the camera shake prevention system. As a feature of the present invention, the controller 6 constituting the system control unit first energizes the position sensor (HaLL element and position detection circuit 8) first when the system shifts from the sleep state to the operation state. Acquires position information representing the position. Next, based on the acquired position information, the current position is set as a target position, the actuator 5 is activated, and the correction lens 3 is held and fixed at the current position. Subsequently, the predetermined initial position (home position) is reset to the target position, the actuator 5 is controlled via the driver 7, and the correction lens 3 is transferred from the current position to the initial position. At that time, the controller 6 controls the actuator 5 from the driver IC 7 to move the correction lens 3 from the current position to the initial position at a constant speed.

  FIG. 3 is a flowchart showing the procedure of the control program executed by the controller 6. As shown in the figure, after this program is started, first, power-on is confirmed in step S1. Subsequently, the power source of the position detection circuit 8 is turned on in step S2. Subsequently, the current position information of the correction lens 3 is obtained from the Hall element via the position detection circuit 8 in step S3. In step S4, the same target position as the current position information is set and output to the driver IC. The driver IC 7 activates the actuator 5 based on an instruction from the controller 6 and sends the correction lens 3 to the target position. Actually, since the target position is set to be the same as the current position of the correction lens 3, the correction lens 3 is fixed at the current position when the actuator 5 is activated.

  Thereafter, in step S5, drive data necessary for transferring the correction lens from the current position to the initial position is calculated. This driving calculation includes setting of a driving time necessary for transferring the correction lens from the current position to the initial position. This driving time is set according to the distance between the current position and the initial position (target position) so that the correction lens is moved at a constant speed. In step S6, an instruction is sent to the driver IC to start driving the correction lens. At that time, a timer is started at the same time and error time measurement is started. This error time is set to detect a system error. In step S7, it is determined whether or not the correction lens has been transferred to the initial position. When the transfer is completed, the program ends. On the other hand, if the transfer is not completed, the process proceeds to step S8, where the time measured by the timer is read to determine whether the error time has elapsed. This procedure S8 is performed periodically. If the error time has not been reached, the process returns to step S7 to determine whether or not the correction lens has reached the initial position. Procedures S7 and S8 are repeated periodically. If the timer counts out during this process (that is, if the error time is reached), the process branches to step S9 to perform predetermined error processing.

  As is apparent from the above description, in the camera shake prevention system of the present invention, when the camera is first turned on, the position detection circuit is turned on. At this time, the coil constituting the actuator is not yet energized, and the driver IC is in a standby state. Next, the controller reads the output of the position detection circuit and energizes the coil via the driver IC so that the position (current position) is the same. At this time, since the indicated position output from the controller and the current position output from the position detection circuit are the same, the correction lens is held and fixed at the current position without moving. Thereafter, the difference between the initial position and the current position is calculated, and a moving time is set so as not to cause a load on the mechanical mechanism. Based on this set time, the controller energizes the actuator via the driver IC to move the correction lens from the current position to the initial position. If there is no difference between the initial position and the current position, this movement time becomes zero. By such an operation, the camera shake prevention device according to the present invention can prevent a rapid operation of the correction lens when the power is turned on, and can reduce the load on the mechanical mechanism. When the current position is close to the initial position (target position), the transfer of the correction lens can be completed in a short time.

It is a schematic diagram which shows the outline | summary of the camera-shake correction apparatus concerning this invention. 1 is a block diagram showing an overall configuration of an embodiment of a camera shake correction apparatus according to the present invention. It is a flowchart with which operation | movement description of embodiment shown in FIG. 2 is provided.

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 ... Correction lens, 4 ... Gyro sensor, 5 ... Actuator, 6 ... Controller, 7 ... Driver IC, 8 ... Position detection circuit

Claims (2)

A camera shake sensor that is attached to the camera and detects camera movement caused by camera shake during shooting operations;
To correct camera shake, a correction lens mounted on the camera barrel,
An actuator for driving the correction lens in a plane intersecting the optical axis of the lens barrel;
A position sensor that detects the position of the correction lens and outputs corresponding position information;
Based on the movement information of the camera detected by the camera shake sensor, drive data including the movement amount of the correction lens is obtained, and the actuator is operated based on the obtained drive data while monitoring the position information output from the position sensor. In the camera shake correction device including the control unit to control,
The control unit first energizes the position sensor to acquire position information indicating the current position of the correction lens and then sets the current position based on the acquired position information. Set the position to activate the actuator to hold the correction lens at the current position, then set the predetermined initial position to the target position and control the actuator to move the correction lens from the current position to the initial position. A camera shake correction device that is transported to a camera.   The camera shake correction apparatus according to claim 1, wherein the control unit controls the actuator to move the correction lens from a current position to an initial position at a constant speed.

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