JP2010102031A - Image blur correction device and optical apparatus having the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the effect of the resonance of a correction lens on a photographing result, the resonance being caused by actuation of a compositional member during a photographing operation. <P>SOLUTION: If an exposure time is shorter than a predetermined time even when an image blur correction switch is off, power is supplied to a coil and the correction lens is electrically held mainly for correction. This reduces the effect of resonance on a photographing result. In addition, if the exposure time is longer than the predetermined time even when the image blur correction switch is off, power is not supplied to the coil since the effect of resonance is small. Accordingly, waste of power consumption is prevented. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an improvement in an optical apparatus having a shake correction unit that corrects an image shake caused by the shake based on a detection result of a shake detection unit that detects a shake applied to an optical device such as a camera.

  To correct image blur caused by camera shake and other effects in optical devices such as cameras, change the optical axis by detecting the vibration of the optical device and moving the correction lens and image sensor according to the detection result. By doing.

In principle, vibration is detected by installing a shake sensor that detects angular acceleration, angular velocity, and the like, and a means for outputting an angular displacement by electrically or mechanically integrating the output signal of the shake sensor. Can be done. Then, based on this detection information, a correction optical system that decenters the photographing optical axis is driven, and the position of the correction optical system is detected and feedback control is performed so that accurate image blur suppression can be performed. ing. (Patent Document 1)
Further, when the correction optical system is not driven, a mechanism for mechanically holding the correction optical system at the correction center is provided. Specifically, there is an apparatus in which the correction optical system is held at the correction center using an elastic body such as a spring and the size is reduced by omitting the mechanical holding means. (Patent Document 2)
JP-A-7-218967 JP-A-8-184870

  1 to 3 show an image blur correction apparatus in which a correction optical system is held at a correction center by a spring. In the image blur correction apparatus of FIG. 1, the correction lens is only held by the spring 35 when the correction operation is not performed. Therefore, when an impact is applied, resonance occurs at the resonance frequency, and depending on the spring constant of the spring 35, the resonance amplitude may become considerably large.

  When shooting with a single-lens reflex camera, mirror driving and shutter driving for shooting operation are performed. When an impact due to such driving is applied to the shake correction device, the correction lens resonates, which may affect photographing.

  Since the resonance amplitude attenuates with time after the impact is applied, the influence is small when the shutter time is long, but the influence becomes large when the shutter time is short. If the spring constant is increased, the resonance amplitude is also reduced. However, when correcting the shake, it is necessary to drive the correction lens against the spring. That is, if the spring constant is increased, the current consumption increases, so it is not preferable to increase the spring constant too much.

  Therefore, in order to prevent resonance, it is necessary to energize the coil 33 by a method to be described later, and to electrically hold the correction lens at the correction center. For this reason, it is preferable to energize for a long time from the viewpoint of power consumption. Absent. Some mounted cameras can shoot without mirror driving or shutter driving, and some mounted cameras do not need to be energized to hold the electrical correction lens.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an image blur correction device for a camera that can reduce the influence of the resonance of the correction lens caused by the operation of the constituent member during the photographing operation on the photographing result.

  The invention according to the present application for achieving the above object includes, as described in claim 1, shake detection means for detecting shake applied to an optical device, a correction lens for correcting image shake caused by the shake, and A shake correction unit that drives the correction lens based on a detection result of the shake detection unit, a selection unit that selects operation or non-operation of the shake correction unit, a control unit that controls the shake correction unit, and the correction lens And an elastic member that holds the correction center at the correction center, wherein the control means has a predetermined exposure time of the optical instrument in a state where the selection means selects the inoperative of the shake correction means. When the time is shorter than the time, the shake correction unit is operated, and when the exposure time of the optical apparatus is longer than the predetermined time, the shake correction unit is kept inoperative. To.

  According to the present invention, even if the user has selected not to operate the shake correction unit, the correction lens caused by the operation of the constituent member is performed by performing the image shake correction when the exposure time is shorter than the predetermined time. The influence of the resonance of the image on the imaging result can be reduced.

  In addition, when the exposure time is longer than a predetermined value, it is possible to prevent wasteful power consumption by not operating the shake correction unit.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described in detail with reference to FIGS.

  In this embodiment, an interchangeable lens that can be attached to and detached from a camera is used as an optical device. In addition, examples of the optical apparatus include a camera body, an interchangeable lens that can be attached to and detached from the camera body, and a general photographing apparatus having an optical system, such as a camera system in which the camera and the lens are integrated.

  FIG. 1 to FIG. 3 show lens driving means of a shake correction lens for correcting image shake caused by shake applied to the camera.

  FIG. 1 is an exploded perspective view of the lens driving means. In FIG. 1, reference numeral 31 denotes a base plate, 36 denotes a movable lens barrel including a correction lens, and 32a, 32b and 32c denote spheres held between the base plate and the movable lens barrel.

  33a and 33b are coils, 34a and 34b are magnets, 35a, 35b, and 36c are elastic bodies (elastic members) that hold the lens at the correction center, and 37 is a magnet suction plate.

  Further, 38a and 38b are suction plate fixing spirals, 39 is a movable lens barrel holding plate, 40 is an FPC, 41a and 41b are FPC fixing spirals, and 101 is a magnet suction plate provided with appropriate holes. Respectively.

  Here, the correction center is a basic position for correction in the movement of the lens in the vertical plane of the optical axis, and is the position of the lens where the optical axis of the photographing optical system coincides with the optical axis of the lens.

  FIG. 2 is a plan view of the lens driving device. 2A is a front view seen from the optical axis direction, and FIG. 2B is a cross-sectional view taken along the line BB in FIG. 2A. As shown in FIG. 2A, the movable barrel 36 is elastically supported by a plurality of elastic bodies 35 with respect to the base plate 31.

  In this embodiment, three elastic bodies are arranged radially from the optical axis at intervals of 120 degrees. By adopting such a symmetrical arrangement, it is possible to suppress excitation of unnecessary resonance due to generation of moment.

  The elastic body is attached with an appropriate inclination in the optical axis direction, and holds the balls 32a, 32b, and 32c provided between the base plate 31 and the movable lens barrel 36.

  The lens driving device and driving means will be described with reference to FIG. As shown in FIG. 1, the driving means has coils 33a and 33b fixed to the base plate 31, and magnets 34a and 34b fixed to the movable lens barrel 36 to constitute a so-called moving magnet type actuator. Yes. In addition, the sensor 102 is provided on the non-opposing side of the coils 33a and 33b with respect to the magnet 34a. In this embodiment, a Hall element is used as a sensor because of a moving magnet type actuator.

  The sensor 102 is fixed to the base plate 31 via the FPC 40, and detects the position of the movable lens barrel 36 by a change in magnetic flux density. Further, by arranging the Hall elements as described above, the driving magnet 34a is also used as a position detecting magnet.

  3A and 3B are schematic views of the driving means. FIG. 3A is a view of the magnet, coil, and sensor as viewed from the optical axis direction, and FIG. 3B is a cross-section when the magnet is cut near the center. The figure is shown.

  In FIG. 3, reference numeral 110 denotes a magnetic sensitive part of the sensor. In the magnetic circuit shown in FIG. 3, the magnetic fluxes 42a, 42b, and 42c flow as shown by arrows in the figure. In the state of FIG. 3B, since the magnetic sensing part 110 is located immediately above the magnetization boundary 43, the magnetic field at this point is substantially equal to zero. The amount of movement at this time is detected as zero.

  When relative movement occurs between the base plate 31 and the movable lens barrel 36, the magnetization boundary 43 moves together with the movable lens barrel 36 as viewed from the sensor 102 fixed to the base plate 31. A magnetic field of 110 shows a non-zero value. In a certain range, the movement amount and the magnetic field strength have a linear relationship, and in this range, the position can be detected linearly.

  FIG. 4 is a block diagram showing the configuration of the present embodiment. In this embodiment, the lens driving means for image blur correction shown in FIGS. 1 to 3 is applied to an interchangeable lens of a single-lens reflex camera as an example. I have to.

  In FIG. 4, reference numeral 10 denotes a lens MPU, which is a control unit that performs lens-side control through communication with the camera MPU 20.

  A sensor 12 detects the position of the lens, and the position is sent to the lens MPU 10 and used for feedback control.

  Reference numeral 11 denotes a shake sensor that detects shake, and an output signal of which a DC component is cut by a high-pass filter and is input to an A / D conversion terminal of the lens MPU 10 via a low-pass filter 13 for amplification and noise removal. The A / D converted shake angular velocity signal is subjected to calculations such as high-pass and integration, and based on the result, the correction lens is driven via the coil driver 14 to perform image shake correction.

  In addition to the image blur correction control as described above, the lens MPU 10 performs zone detection based on a signal from the zoom / focus position detector 15 and drives the focus lens and the diaphragm via the motor drivers 16 and 17. Yes.

  Reference numeral 18 denotes a switch (ISSW) which is a selection unit and can select whether to activate or deactivate image blur correction (Image Stabilizer).

  Reference numeral 19 denotes a switch (A / MSW) for selecting auto focus or manual focus.

  The lens MPU 10 communicates with the camera MPU 20 to check the status (focal length, state of each switch, etc.) of the camera and lens, and to transmit driving commands such as shutter speed, focus, and aperture.

  The release switch 21 is generally a two-stage stroke switch. The switch SW1 (not shown) is turned on by the first stroke of the release switch 21, and the switch SW2 (not shown) for release is turned on by the second stroke. It is configured to be.

  Here, a specific operation of the lens MPU 10 will be described with reference to the flowchart of FIG. When the lens is attached to the camera, serial communication is performed from the camera MPU 20 to the lens MPU 10, and the lens MPU 10 starts its operation from step # 501.

  (Step # 501) Initial setting for lens control and image blur correction control is performed.

  (Step # 502) The state detection of the switches 18 and 19 and the position of zoom / focus are detected.

  (Step # 503) It is determined whether or not the first stroke SW1 of the release switch 41 is ON. When SW1 is OFF, no special operation is performed and the process proceeds to step # 507.

  (Step # 504) If SW1 is ON in Step # 503, it is next determined whether or not there is a focus drive request communication from the camera MPU10. If there is a focus drive request, the process proceeds to step # 505. If not, the process proceeds to step # 506.

  (Step # 505) Since the driving amount of the focus lens is commanded from the camera MPU 20, focus drive control is performed accordingly, and the process returns to step # 502 to repeat the process.

  (Step # 506) If there is no focus drive request, image blur correction operation start control such as setting of an image blur correction start flag is performed according to the communication from the camera MPU 20 and the state of the switch 18.

  (Step # 507) It is determined whether or not a command for stopping all driving (stopping all driving of the actuators in the lens) is received from the camera MPU20. If no operation is performed on the camera side, this all drive stop command is transmitted from the camera MPU 20 after a while. If not received, the process returns to step # 502 to repeat the process.

  (Step # 508) All drive stop control is performed. Here, the driving of all actuators is stopped, and the lens MPU 10 enters a sleep (stopped) state. Power supply to the image shake correction apparatus is also stopped. Thereafter, when any operation is performed on the camera side, the camera MPU 20 sends a communication to the lens MPU 10 to cancel the sleep state.

  During these operations, if there is a request for serial communication interruption or image blur correction interruption by communication from the camera MPU 20, the interruption processing is performed.

  In the serial communication interrupt, communication data is decoded, and lens processing such as aperture driving is performed according to the decoding result. Then, by decoding the communication data, it is possible to determine ON of the switch SW1, ON of the switch SW2, shutter time (exposure time), camera model, and the like. Thereby, the image blur correction operation can be started by turning on the switch SW1 of the camera.

  Next, the image blur correction operation will be described with reference to the flowchart of FIG. The image blur correction operation is activated by a timer interrupt that occurs at regular intervals (for example, 500 μsec).

  The lens MPU 10 starts the image blur correction operation from step # 601 in FIG. Step 601 is a selection step, step 603 is a shake detection step, and step 613 is a comparison step.

  (Step # 601) It is determined whether or not the switch 18 for selecting whether to perform image blur correction is ON. If it is ON, the process proceeds to step # 602. If it is OFF, the process proceeds to step # 612.

  (Step # 602) It is determined whether SW1 of the two-stage stroke switch is pressed. If SW1 is ON, the image blur correction operation is entered, and the process proceeds to step # 603. If SW1 is not pressed, the image blur correction operation is not performed and the process ends.

  (Step # 603) The output of, for example, the angular velocity sensor that is the shake sensor 32 is obtained by A / D conversion.

  (Step # 604) A high-pass filter operation is performed to operate image blur correction. The time constant is switched for 2 to 3 seconds from the start of the image blur correction, and the rising image shake is also reduced.

  (Step # 605) An integral calculation of the set characteristic is performed. This result is angular displacement data θ. When panning is performed, the integration cutoff frequency is switched according to the deflection angular displacement.

  (Step # 606) Since the decentering amount (sensitivity) of the correction lens with respect to the shake angle displacement changes depending on the detection result from the zoom / focus position detector 15, that is, the zoom / focus position, the adjustment is performed. Specifically, the zoom and focus positions are each divided into several zones, and the average image stabilization sensitivity (deg / mm) in each zone is read from the table data and converted into correction lens drive data. The calculation result is stored in a RAM area set by SFTDRV in the lens MPU 10.

  (Step # 607) The displacement signal of the image blur correction lens is A / D converted, and the A / D result is stored in a RAM area set by SFTPST in the lens MPU10.

  (Step # 608) A feedback calculation (SFTDRV-SFTPST) is performed. The calculation result is stored in a RAM area set by SFT_DT in the lens MPU 10.

  (Step # 609) The loop gain LOG_DT is multiplied by the calculation result SFT_DT of step # 608. The calculation result is stored in a RAM area set by SFT_PWM in the lens MPU 10.

  (Step # 610) In order to obtain a stable control system, a phase lead compensation calculation is performed.

  (Step # 611) The calculation result of step # 609 is output as PWM to the port of the lens MPU 10, and the image blur correction operation is completed. The output is input to the coil driver 14, the correction lens is driven by the coil and the magnet, and image blur correction is performed.

  (Step # 612) When the switch 18 for selecting whether or not to perform image blur correction is set to OFF in Step # 601, SW2 of the two-stage stroke switch which is a switch for selecting the next exposure start. It is determined whether or not is ON.

  If SW2 is ON, the process proceeds to step # 613. When SW2 is OFF, the image blur correction operation is terminated.

  (Step # 613) It is determined whether the next set exposure time is longer than a predetermined value Tv. If it is determined that it is longer than Tv, the influence of vibration caused by mirror driving or shutter driving and the resonance of the spring holding the correction lens is considered to be sufficiently small. Maintain inactivity (end). On the other hand, if it is determined that the exposure time is shorter than Tv, it is considered that the influence of the spring resonance is increased. Therefore, the process proceeds to step # 614, and the image blur correction operation for preventing the spring resonance is activated.

  (Step # 614) The lens drive amount is set to 0 and stored in the RAM area set by SFTDRV in the lens MPU10 so that the vibration generated by the mirror drive or shutter drive and the spring holding the correction lens do not resonate. To do.

  By performing the processing from step # 607 in this state, control is performed so that the position of the correction lens does not move due to vibration, and as a result, the correction lens is electrically held.

  That is, during the exposure period, resonance between the spring that holds the correction lens and vibration caused by mirror driving or shutter driving can be prevented.

  As described above, it is possible to prevent the quality of the image from deteriorating because the influence of resonance due to the impact of the mirror and shutter is large.

  In addition, it is possible to prevent wasteful power consumption by adopting a configuration in which the correction lens is electrically held only when the exposure time is shorter than the predetermined time and the image quality is affected.

  In this embodiment, a physical selection switch is used as a selection unit that can select driving to the shake correction unit. However, the present invention is not limited to this, and a memory for storing information about whether the shake correction unit is activated or deactivated may be provided and used as the selection unit.

(Second Embodiment)
In the second embodiment of the present invention, as in the first embodiment, the lens driving means for image blur correction shown in FIGS. 1 to 3 is applied to an interchangeable lens of a single-lens reflex camera or the like. It is an example.

  In addition to the first embodiment, the correction lens is electrically held in accordance with the mounted camera. The circuit configuration is the same as in FIG. 4, and the operation of the lens MPU 10 is also the same as in FIG.

  Hereinafter, a second embodiment of the present invention will be described with reference to the flowchart of FIG.

  The description of the same part as the flowchart of FIG. 6 which is the first embodiment is omitted, and only step # 714 which is an operation part peculiar to the present embodiment will be described. Step 714 is a determination step.

  In step # 714, it is determined whether or not the type of the attached camera is A type.

  If it is not the A type, the process proceeds to step # 715, and as shown in the first embodiment, the correction lens is electrically held at the correction center by setting the lens driving amount to 0 and performing image blur correction control. To do.

  If the type is A, the process ends without performing the image blur correction operation.

  Here, specific examples of the A type camera are cameras that do not vibrate during shooting, such as cameras that do not perform mirror driving, cameras that perform mirror driving or less shutter impact, and digital cameras.

  A camera that is not the A type indicates a camera that has a greater impact of mirror or shutter driving than an A type camera.

  As described above, the model of the camera is determined in step # 714, and the model in which the correction lens spring resonance is greatly influenced by the impact of the mirror driving or the like at the time of photographing is electrically held in the correction lens, and the model having the less influence In this case, the instability of the shake correction means is maintained. Thereby, depending on the camera model, it is possible to achieve an effect of not taking an image that is not affected by the spring resonance or performing a useless correction operation.

1 is an exploded perspective view of an image shake correction apparatus according to an embodiment of the present invention. 1A and 1B are a plan view and a cross-sectional view of an image shake correction apparatus according to an embodiment of the present invention. It is explanatory drawing of the drive means of the image blur correction apparatus which concerns on embodiment of this invention. It is a block diagram which shows the structure of the camera system which concerns on embodiment of this invention. It is a flowchart showing operation | movement of lens MPU which concerns on embodiment of this invention. 3 is a flowchart illustrating an image blur correction operation according to the first embodiment of the present invention. 7 is a flowchart illustrating an image blur correction operation according to the second embodiment of the present invention.

Explanation of symbols

10 Lens MPU
18 Selection switch 31 Base plate 33a, 33b Coil 34a, 34b Magnet 35a, 35b, 35c Elastic body 36 Movable lens barrel 37 Magnet adsorption plate 38 Sensor

Claims (8)

Shake detection means for detecting shake applied to the optical device;
A correction lens that corrects image blur caused by the shake;
A shake correction unit that drives the correction lens based on a detection result of the shake detection unit;
Selection means for selecting operation or non-operation of the shake correction means;
Control means for controlling the shake correction means;
In an image blur correction device having an elastic member that holds the correction lens at the correction center,
The control means operates the shake correction means when the exposure time of the optical apparatus is shorter than a predetermined time in a state where the selection means selects the non-operation of the shake correction means, and the optical apparatus When the exposure time is longer than the predetermined time, the instability of the shake correction unit is maintained. Shake detection means for detecting shake applied to the optical device;
A correction lens that corrects image blur caused by the shake;
A shake correction unit that drives the correction lens based on a detection result of the shake detection unit;
Selection means for selecting operation or non-operation of the shake correction means;
Control means for controlling the shake correction means;
In an image blur correction device having an elastic member that holds the correction lens at the correction center,
The control means includes
In the state where the selection means has selected the non-operation of the shake correction means,
When the optical device is a device having a small impact when driving a mirror or a shutter of the optical device, maintaining the non-operation of the shake correction unit,
When the optical device is a device that has a large impact when the mirror or shutter of the optical device is driven, and the exposure time of the optical device is shorter than a predetermined time, the shake correction means is operated, and the optical device When the exposure time of the apparatus is longer than a predetermined time, the image blur correction apparatus is characterized in that the blur correction unit is not operated.   An optical apparatus having the image blur correction device according to claim 1.   The optical apparatus according to claim 3, wherein the optical apparatus is an interchangeable lens that can be attached to and detached from a camera.   The optical apparatus according to claim 3, wherein the optical apparatus is a camera to which an interchangeable lens can be attached and detached.   The optical apparatus according to claim 3, wherein the optical apparatus is a camera system in which a camera and a lens are integrated. A shake detection step for detecting shake applied to the optical device;
A shake correction step of driving shake correction means for driving a correction lens based on the detection result of the shake detection step;
A selection step of selecting operation or non-operation of the shake correction means;
Comparing the exposure time of the optical instrument with a predetermined time,
When the exposure time of the optical device is shorter than a predetermined time in the state where the inactivation of the shake correction unit is selected in the selection step, the shake correction unit is operated and the exposure time of the optical device is A control method for an image blur correction apparatus, characterized in that the blur correction means is kept inactive when longer than a predetermined time. A shake detection step for detecting shake applied to the optical device;
A shake correction step of driving shake correction means for driving a correction lens based on the detection result of the shake detection step;
A selection step of selecting operation or non-operation of the shake correction means;
A comparison step of comparing an exposure time of the optical instrument with a predetermined time;
Determining whether the optical device is a device having a large impact or a small device when the mirror or shutter of the optical device is driven, and
In the state where the operation of the shake correction means is selected in the selection step,
When it is determined in the determination step that the device has a small impact when the mirror or shutter of the optical device is driven, the instability of the shake correction unit of the optical device is maintained,
When it is determined in the determination step that the device has a large impact when the mirror or shutter of the optical device is driven, and the comparison step determines that the exposure time of the optical device is shorter than a predetermined time. The image is characterized in that the shake correction means is activated and the shake correction means is kept inactive when the comparison step determines that the exposure time of the optical instrument is longer than the predetermined time. Control method of shake correction apparatus.

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