JP5241396B2 - Optical member control device and control method, lens barrel, imaging device, and control method - Google Patents

Description

  The present invention relates to an optical member control device that drives an optical member such as a lens group, a lens barrel, and an imaging device.

In imaging devices represented by still cameras and video cameras, for example, automatic focus adjustment is performed by detecting the sharpness of the screen from the video signal of the subject and controlling the position of the focus lens so that it is maximized. (AF) devices are known. Conventionally, DC motors and stepping motors have been generally used as means for driving a focus lens for performing automatic focus adjustment. However, in recent years, with higher functionality and higher pixels of imaging devices, high-speed and quiet lens driving and lens driving with high stopping accuracy are required. For this reason, a mechanism for driving the lens group in the optical axis direction using a so-called voice coil motor in which a coil is disposed in a magnetic circuit composed of a magnet and a yoke has been proposed (Patent Document 1).
Further, as a control method of the automatic focus adjustment apparatus, a method is disclosed in which after the focusing operation of the focus lens, the AF evaluation value at that time is stored, and when the AF evaluation value changes by a predetermined ratio or more, the focusing operation is performed again. (Patent Document 2). According to this method, power consumption can be reduced by turning off the motor power after the focusing operation of the focus lens. Further, when the change in the AF evaluation value is monitored and the change in the evaluation value is equal to or greater than a predetermined value, the motor power supply is started again to perform the focusing operation, thereby preventing out-of-focus blur.
JP-A-7-239437 JP-A-9-284632

  However, in the case of a focus mechanism using a voice coil motor as disclosed in Patent Document 1, when the voice coil motor is not energized, the position of the focus lens on the mechanism is not fixed. Therefore, it is necessary to always energize the voice coil motor to fix the lens position to maintain the lens position, and there is a problem that power consumption increases.

  An object of the present invention is to reduce power consumption while holding an optical member at a stop position in a configuration in which the position of the optical member is not fixed when energization is stopped, such as when the optical member is driven by a voice coil motor. An optical member control device, a lens barrel, and an imaging device are provided.

An optical member control device according to a first aspect of the present invention comprises a part of a photographing optical system, an optical member that changes a focal state by moving along an optical axis of the photographing optical system, and the optical a driving unit for driving the member, control for moving stores focus position of the optical member to be in-focus state at the focus adjustment operation as a stop position, the optical member by controlling the drive unit to the stopping position And a state detection unit that detects a change in the state related to the position or movement of the optical member, and the drive control unit is configured to adjust the position of the optical member in the focus adjustment operation. The optical member is stopped at the stop position by stopping energization to the drive unit when it is determined that the position is a focal position, and the detection result by the state detection unit is determined to Place to resume energization The have rows holding operation for holding the optical member to the stop position, determines whether to perform the focusing operation again, performs the holding operation of the optical member continue if not performed focal point adjustment operation to It is characterized by determining whether or not .

  The lens barrel according to the second aspect of the present invention includes the optical member control device according to the first aspect of the present invention.

An imaging device as a third aspect of the present invention includes the optical member control device according to the first aspect of the present invention, and an imaging unit that captures an image obtained through the optical member.
In the control method according to the fourth aspect of the present invention, in the drive control of the optical member, the drive control unit drives the drive when the focus adjustment operation determines that the position of the optical member is the focus position. The optical member is stopped at the stop position by stopping the energization of the part, and when the detection result by the state detection unit is determined and the energization to the drive unit is resumed, the optical member is A step of performing a holding operation for holding at a stop position, a determination step for determining whether or not to perform a focus adjustment operation again after the holding operation, and a determination that the focus adjustment operation is not performed in the determination step. In this case, the method includes a step of determining whether or not to hold the optical member.

  According to the present invention, in a configuration in which the position of the optical member is not fixed when energization is stopped, such as when the optical member is driven by a voice coil motor, power consumption is reduced while the optical member is held at the stop position. it can.

The best mode for carrying out the present invention will be described below with reference to the drawings.
In addition, each figure shown below is the figure shown typically, and in order to make an understanding easy, the magnitude | size and shape of each part are exaggerated suitably.
In the following description, specific numerical values, shapes, materials, and the like are shown and described, but these can be changed as appropriate.
Further, in the following description, unless otherwise specified, the wording indicating the direction such as front-rear is based on the time when the camera is in the normal position and the subject side is the front.
Here, the normal position means that when the photographer holds the camera in a normal state, that is, in a state where the optical axis of the photographing optical system is horizontal and the longitudinal direction of the photographing screen is horizontal. It shall refer to the position when held.

(First embodiment)
FIG. 1 is an exploded perspective view around a lens barrel of a first embodiment of a camera using an optical member control device according to the present invention.
The lens barrel of the first embodiment is a lens barrel having a two-stage collapsible type three-group lens configuration. The first group lens 101, the second group lens 102, and the third group are arranged in order from the subject side (left side in the drawing). The lens 103 is disposed in the optical path of the photographing optical system constituted by these.
The first group lens 101 constitutes a part of the photographing optical system and is held by the first lens barrel 105. The first group lens 101 is a zoom lens that changes the magnification by moving along the optical axis direction and changing the position.
The second group lens 102 forms a part of the photographing optical system, and is held by the second lens barrel 106 so as to be movable relative to other lens groups within a plane perpendicular to the optical axis. . The second group lens 102 is a shift lens that performs a blur correction operation for correcting image blur by moving (shifting) in the above-described plane.
The third group lens 103 constitutes a part of the photographing optical system, is held by the third lens barrel 107, and can move together with the third lens barrel 107 in a direction along the optical axis. The third group lens 103 is a focus lens that performs a focusing operation (focus adjustment) by changing a focus state by moving in a direction along the optical axis.
The subject image that has passed through the photographing optical system constituted by these three lens groups 101, 102, and 103 is photoelectrically converted by the image sensor 104 via the low-pass filter 110 and imaged.

The imaging element 104 is an imaging unit that photoelectrically converts and captures a subject image formed by the imaging optical system, and is held by the imaging element base plate 109.
A cover barrel 111 is fixed to the image sensor base plate 109. The image sensor base plate 109 is provided with a speed reduction mechanism including a drive gear 113. This deceleration mechanism decelerates the rotational driving force output from the zoom motor 114 and transmits it to the drive cylinder 112.
A drive cylinder 112 is rotatably held by the cover barrel 111 and the image sensor base plate 109.
The drive cylinder 112 is formed in a cylindrical shape, and the drive gear 113 is engaged with a gear portion 112 a provided on the outer peripheral portion, and is driven to rotate by the rotation of the zoom motor 114. Further, three linear grooves 112b extending in the optical axis direction are formed in the inner peripheral wall of the drive cylinder 112 at equal intervals in the circumferential direction.

Inside the drive cylinder 112, a fixed cylinder 115 fixed to the cover barrel 111 and the image sensor base plate 109 is disposed.
In the fixed cylinder 115, three feed cams 115a each having a through groove shape are formed at equal intervals in the circumferential direction. Further, on the inner peripheral wall of the fixed cylinder 115, three feeding taper cams 115b are formed at equal intervals in the circumferential direction. The feeding cam 115a and the feeding taper cam 115b have the same cam locus. Further, three rectilinear grooves 115c extending in the optical axis direction are formed on the inner peripheral side of the fixed cylinder 115 at equal intervals in the circumferential direction.

A movable cam cylinder 116 is disposed inside the fixed cylinder 115.
The movable cam cylinder 116 is formed in a cylindrical shape, and a follower pin 116a and a drive pin 116b serving as a cam follower are provided on the outer peripheral portion thereof.
The drive pin 116b is provided at a position closer to the image sensor 104 than the follower pin 116a.
A taper portion is formed at the tip of the follower pin 116 a, and this taper portion is engaged with the feeding taper cam 115 b of the fixed cylinder 115.
The drive pin 116b engages with the feed cam 115a of the fixed cylinder 115 and also penetrates the feed cam 115a and engages with the rectilinear groove 112b.
Further, on the inner periphery of the movable cam cylinder 116, three tapered cams 116c and 116d are formed at equal intervals in the circumferential direction.
When the drive cylinder 112 is rotated around the optical axis by the driving force of the zoom motor 114, the drive pin 116b is engaged with the rectilinear groove 112b, so that the follower pin 116a of the movable cam cylinder 116 is fixed to the feed taper cam 115b of the fixed cylinder 115. It moves in the optical axis direction by lift.

A rectilinear cylinder 117 is disposed inside the movable cam cylinder 116.
The rectilinear cylinder 117 is formed in a cylindrical shape, and three protrusions 117a are formed at equal intervals in the circumferential direction on the outer peripheral portion on the rear end side. The protruding portion 117 a is engaged with a rectilinear groove 115 c formed on the inner peripheral side of the fixed cylinder 115.
Therefore, the rectilinear cylinder 117 can move in the optical axis direction with respect to the fixed cylinder 115, but is prevented from rotating around the optical axis.
Further, three protrusions 117 b are formed at equal intervals in the circumferential direction on the outer periphery of the front end portion of the rectilinear cylinder 117, and the protrusions 117 b are in contact with the front end of the movable cam cylinder 116. Therefore, when the movable cam cylinder 116 moves in the optical axis direction, the rectilinear cylinder 117 moves in the optical axis direction integrally with the movable cam cylinder 116, but does not rotate around the optical axis. Further, the rectilinear cylinder 117 is formed with three through-groove rectilinear grooves 117c extending in the optical axis direction at equal intervals in the circumferential direction.

  On the other hand, three follower pins 105 a are formed at equal intervals in the circumferential direction on the outer peripheral portion of the first lens barrel 105. The follower pin 105a passes through the rectilinear groove 117c of the rectilinear cylinder 117, and a tapered portion formed at the tip of the follower pin 105a is engaged with the taper cam 116c. Therefore, the first lens barrel 105 moves in the optical axis direction by the lift of the taper cam 116c in conjunction with the movement of the movable cam barrel 116 in the optical axis direction while rotating.

Further, three follower pins 106 a are formed at equal intervals in the circumferential direction on the outer peripheral portion of the second barrel 106. The follower pin 106a passes through the rectilinear groove 117c of the rectilinear cylinder 117, and a tapered portion formed at the tip of the follower pin 106a is engaged with the taper cam 116d. Therefore, the first lens barrel 105 moves in the optical axis direction by the lift of the taper cam 116d in conjunction with the movement of the movable cam barrel 116 in the optical axis direction while rotating.
The second lens barrel 106 is provided with a shutter / aperture unit 108 in addition to the second group lens 102.

FIG. 2 is a block diagram showing a camera using the optical member control apparatus according to the present invention.
The camera of the first embodiment is an imaging device that captures a subject image obtained by a lens barrel having a photographing optical system including a first group lens 101, a second group lens 102, and a third group lens 103 as a still image or a moving image. .
The zoom drive control unit 401 drives and controls movement in the direction along the optical axis of the first group lens 101 as a zoom lens. Specifically, the zoom drive control unit 401 controls driving of the first group lens 101 by controlling energization to the zoom motor 114. The zoom drive control unit 401 controls the movement of the first group lens 101 in the optical axis direction, so that the driving of the shutter / aperture unit 108 and the second group lens 102 in the direction along the optical axis is also controlled.

The shutter / aperture unit drive control unit 402 controls the drive of the shutter / aperture unit 108. Here, the drive control of the shutter / aperture unit 108 refers to the opening / closing of the shutter and the drive control of the aperture opening diameter.
The shift lens drive control unit 403 drives and controls movement (shift) in a plane perpendicular to the optical axis of the second group lens 102 as a shift lens.
The focus drive control unit 404 is a drive control unit that controls movement in the direction along the optical axis of the third group lens 103 as a focus lens.
The imaging signal processing unit 405 converts the electrical signal output from the imaging element 104 into a video signal.
The video signal processing unit 406 processes the video signal output from the imaging signal processing unit 405 according to the application.
The display unit 407 displays an image as necessary based on the signal output from the video signal processing unit 406.
The display control unit 408 controls the operation / display of the image sensor 104 and the display unit 407.

The posture information control unit 409 performs settings corresponding to the posture of the photographing apparatus with respect to the video signal processing unit 406 and the display unit 407 based on information obtained from the posture determination unit 416 described later.
The control unit 410 controls the entire camera.
The power supply unit 411 supplies power to the entire camera according to the application.
The external input / output terminal unit 412 inputs and outputs communication signals and video signals with the outside.
The operation unit 413 is operation input means such as various buttons and a touch panel for operating the camera. The operation unit 413 has a shutter release button (not shown) configured such that the first switch and the second switch are sequentially turned on according to the amount of pressing. The first switch is turned on when the shutter release button is depressed approximately halfway, and the second switch is turned on when the shutter release button is depressed to the end.
The storage unit 414 stores various data such as video information.
The posture sensor 415 outputs a signal corresponding to the posture of the camera to the posture determination unit 416 using the tilt sensor.
The posture determination unit 416 determines what state the camera is in, based on the signal obtained from the posture sensor 415, and outputs the determination result to the control unit 410.

Next, the operation of the camera of this embodiment will be described.
When the first switch of the shutter release button of the operation unit 413 is turned on, the focus drive control unit 404 drives the third group lens 103 to perform focus adjustment, and the shutter / aperture unit drive control unit 402 performs the shutter / aperture 108. To set an appropriate exposure amount. Further, when the shutter release button of the operation unit 413 is pressed and the second switch is turned on, the image data obtained from the optical image exposed on the image sensor 104 is stored in the storage unit 414.
At this time, if the photographer operates the operation unit 413 and the blur correction function is turned on, the control unit 410 instructs the shift lens drive control unit 403 to perform the blur correction operation. Upon receiving this instruction, the shift lens drive control unit 403 performs a shake correction operation until an instruction to turn off the shake correction function is issued.

In the present embodiment, when the operation unit 413 has not been operated for a certain period of time, the control unit 410 instructs the display unit 407 to shut down and not display for power saving.
In the camera of this embodiment, one of the still image shooting mode and the moving image shooting mode can be selected by the operation unit 413, and the operation condition of each actuator control unit can be changed in each mode.
Further, when there is an operation for causing the operation unit 413 to perform zooming with the first group lens 101, the zoom drive control unit 401 that has received an instruction via the control unit 410 drives the first group lens 101 and is instructed. The first group lens is moved to the zoom position.
Further, based on image information sent from the image sensor 104 and processed by the image signal processing unit 405 and the video signal processing unit 406, the focus drive control unit 404 drives the third group lens 103 to perform focus adjustment.

FIG. 3 is an exploded perspective view showing the driving mechanism of the third group lens 103 and the image sensor base plate 109.
FIG. 4 is a perspective view showing a state in which the driving mechanism of the third group lens 103 and the image sensor base plate 109 are assembled.
The driving mechanism of the third group lens 103 of the present embodiment uses a voice coil motor as a drive unit that drives the third group lens 103.
The voice coil motor of this embodiment includes a coil 118a, a magnet 118b, and a yoke 118c.
The coil 118a is fixed to the third lens barrel 107, and the flexible substrate 119 is electrically connected.
The magnet 118 b and the yoke 118 c are fixed to the image sensor base plate 109 via the fixing member 120.

A guide shaft 121 is attached to the image sensor base plate 109 by a support member 122 so as to be parallel to the optical axis. The support member 122 is fixed to the image sensor base plate 109 with screws.
The third lens barrel 107 is fitted so that the fitting portion 107 a can move with respect to the guide shaft 121. Therefore, the third lens barrel 107 can smoothly move straight in the direction along the optical axis.

When the coil 118a is energized through the flexible substrate 119 under the control of the focus drive controller 404, the third lens barrel 107 is guided by the guide shaft 121 by the action of the magnetic circuit formed by the magnet 118b and the yoke 118c. Driven in a direction along the optical axis.
On the other hand, when the coil 118a is not energized, the third lens barrel 107 is guided by the guide shaft 121 and is freely movable in the direction along the optical axis, and is not held at a specific position.
The movable range of the third lens barrel 107 includes the support member 122 and the third lens barrel 107 fixed to the image sensor base plate 109 by screws from the abutting surfaces of the image sensor base plate 109 and the third lens barrel 107. To the butting surface.

Further, the driving mechanism of the third group lens 103 according to the present embodiment includes a position detection unit that detects the position of the third group lens 103 as a state detection unit that detects a change in the state related to the position or movement. . The position detection unit of the present embodiment includes a sensor 123a and a scale 123b.
The scale 123 b is elastically held by the third lens barrel 107 by the elastic holding member 124. Grooves are formed at a predetermined pitch in the scale 123b, and function as an optical linear scale when used with the sensor 123a.
In addition, a sensor 123 a is attached to the imaging element base plate 109 by a fixing member 120 so as to face the scale 123 b with a predetermined interval. A light emitting element and a light receiving element are mounted on the sensor 123a. A light beam emitted from the light emitting element is reflected by a groove portion of the scale 123b, and an output signal is obtained by receiving the reflected light beam by the light receiving element. For example, an SR sensor or the like can be used as the sensor 123a.

FIG. 5 is a diagram illustrating an example of an output of a periodic waveform obtained from the light receiving element of the sensor 123a.
When the third lens barrel 107 with the scale 123b fixed moves with respect to the fixed sensor 123a, a sine wave signal having a phase difference of 90 degrees as shown in FIG. 5 is output from the sensor 123a. From these two-phase outputs, the movement amount and movement direction of the scale 123b can be determined. Here, the initial position of the third lens barrel 107 is determined by abutment between the third lens barrel 107 and the image sensor base plate 109.
The output of the sensor 123a may be three or more phases. Further, the phase angle may be an angle other than 90 deg. Further, the initial position of the third lens barrel 107 may be determined by providing an initial position detecting sensor and outputting from the sensor.

Next, the focus operation of the camera of this embodiment will be described.
FIG. 6 is a flowchart showing the focus operation of the first embodiment.
FIG. 7 is a state transition diagram showing changes in stop and restart of the voice coil motor of the first embodiment.
When the processing is started in step (hereinafter referred to as S) 1, first, in S2, the AF evaluation value is calculated while slightly driving the third group lens 103 by the wobbling operation, and it is blurred whether the focus is currently in focus. Judge whether or not. Here, the AF evaluation value is an evaluation value (focus evaluation value) of the degree of focus for the image in the focus detection area obtained from the image sensor 104 during the movement of the third group lens 103. The value represented can be used. In the present embodiment, the control unit 410 calculates an AF evaluation value. The wobbling operation is an operation in which the third group lens 103 is repeatedly reciprocated in a minute range in the direction along the optical axis.

In S3, based on the result of the wobbling operation in S2, it is determined whether or not the in-focus state is present, that is, whether or not the third group lens 103 is in the in-focus position that is the stop position of the AF operation.
If it is determined that the image is out of focus, the process proceeds to S4, and a mountain climbing operation is executed in the direction of the determination result by the wobbling operation.
Next, in S5, it is determined whether or not the focal point, that is, the vertex of the AF evaluation signal has been exceeded. If the vertex of the AF evaluation signal is not exceeded, the mountain climbing is continued, and if it exceeds, the third group lens 103 is returned to the vertex in S6 and S7.
However, since the subject may change due to panning or the like while returning to the vertex, if the third lens group 103 arrives at the vertex in S7, the current position is really the vertex, that is, the focal point. In order to determine whether or not there is a return to S2, the wobbling operation is performed again. As described above, when it is determined in S3 that the in-focus state is not achieved, the wobbling is repeated until the in-focus state is completed.

On the other hand, when it is determined in S3 that the focus is achieved, the focus drive unit 404 turns off the power to the coil 118a of the voice coil motor, stops the third group lens 103, and proceeds to the restart monitoring process routine from S8.
This corresponds to a state in which focusing is completed (805) from the wobbling state (801) shown in FIG. 7 and a transition is made to the AF end state (802).

In the restart monitoring process routine, first, the AF evaluation value level at the time of focusing is stored in S8.
In S9, the current stop position of the third group lens 103 is stored as a holding position in a holding operation described later.
In S10, in order to reduce power consumption by energizing the coil 118a of the voice coil motor, the energization to the coil 118a of the voice coil motor is stopped and the operation of the voice coil motor is stopped (FIG. 7: Motor stopped state (803). )).
Here, energization to the coil 118a of the voice coil motor is stopped to reduce power consumption as described above. However, in order to detect the subsequent movement of the lens position, the power of the position detection sensor 123a of the third group lens 103, the posture sensor 415 for detecting the posture change of the camera, and the power of the posture determination unit 416 are not turned off. Energization of these continues.

In S11, it is determined whether the display of the display unit 407 is turned on or whether the display unit 407 is turned off and the display is turned off. If the display is on, the process proceeds to S14, and if the display is off, the process proceeds to S12.
In S12, after moving the third group lens 103 to the AF start position, the energization of the coil 118a of the voice coil motor is stopped, and the operation of the voice coil motor is stopped.
In S13, the AF start position, which is the current stop position of the third group lens 103, is stored as a holding position in a holding operation described later.
As described above, in the present embodiment, when the display is off in conjunction with the on / off of the display of the display unit 407 that displays the captured image, the third group lens 103 is set in advance by a holding operation described later. The AF start position is held. Thereby, when the display is resumed and the AF operation is resumed, the AF operation can be quickly started. Note that the position where the third group lens 103 is held when the display of the display unit 407 is off may be a position other than the AF start position.

In S14, a holding energization determination routine is started. The holding energization determination routine is a routine for determining whether or not energization of the voice coil motor is necessary to hold the position of the third group lens 103.
Specifically, in S15, the sensor 123a that detects the position of the third group lens 103 is used to store the current position of the third group lens 103 and the current position in S9 or S13 by the focus drive control unit 404 every certain period. The position of the third group lens 103 immediately before stopping the placed voice coil motor is compared. This comparison is performed by obtaining the absolute value of the difference between the current position of the third lens group 103 and the position of the third lens group 103 immediately before the voice coil motor is stopped, and comparing this with a preset threshold value.
Here, the threshold value is a value corresponding to the depth of field. Therefore, the threshold value is set so as to change depending on the focal length and aperture value of the photographing optical system at that time. This is because the shift of the focus position that affects the AF focus varies depending on the depth of field.
In addition, as a value used for obtaining the difference in position, the actual position may be a dimension such as μm, or data obtained from the sensor 123a may be directly used.

In S15, if the absolute value of the difference between these positions is within the threshold value, that is, the amount by which the current position of the third group lens 103 is moved from the position of the third group lens 103 immediately before the voice coil motor is stopped is within a preset amount. Then, it is determined that the holding energization is unnecessary, and the process proceeds to S16.
In S16, the motor stop state is maintained.

On the other hand, if it is determined in S15 that the position change of the third group lens 103 is equal to or greater than the threshold value, it is determined that the holding current to the coil 118a of the voice coil motor is necessary (FIG. 7: lens position change 810). , Go to S17.
In S17, the voice coil motor is restarted (FIG. 7: motor restart state 804).
In S18, holding energization to the coil 118a of the voice coil motor is started, and drive control for holding the third group lens 103 at the holding position is performed.

  Note that the energization of the motor to the coil 118a of the voice coil motor is also started when the shutter release button of the operation unit 413 is pressed. Immediately after the release button is pressed, the lens position is not stabilized by the holding operation. The exposure is started after a predetermined time necessary for the position to stabilize.

Thereafter, in S19, a re-AF determination routine for performing re-AF determination (determination of whether or not it is necessary to perform AF operation again) based on the AF evaluation value is performed.
In this re-AF determination routine, the re-AF determination is performed based on the degree of fluctuation of the current AF evaluation value level compared to the level stored in S8 at the time of focusing. For example, if it changes by a predetermined percentage or more with respect to the stored level, it is determined that the subject has changed due to panning or the like, and “re-AF operation is necessary”. It is determined that a second AF operation is unnecessary.
In S20, it is determined whether or not the re-AF condition is satisfied. If it is satisfied, the process returns to S2 (FIG. 7: AF evaluation value change detection (812)), and the wobbling operation is again performed (FIG. 7: during wobbling (801)). Transition.
On the other hand, if the re-AF condition is not satisfied in S20, there is no need for re-AF, so the process returns to the holding energization determination routine S14 again to determine whether it is necessary to continue holding energization. Here, if the movement amount of the third group lens 103 is within the predetermined range again, the voice coil motor is stopped again in S16, and the process returns to the holding energization determination routine S14.
Although not shown, when it is determined in S11 that the display on the display unit 407 is off, the re-AF determination routine is skipped and S14 is performed.

  As described above, in the present embodiment, since the holding operation is performed only when the position of the third group lens 103 is changed, the time for holding and energizing the coil 118a of the voice coil motor can be reduced. Therefore, the position of the third group lens 103 can be held at a specific position while reducing power consumption.

(Second Embodiment)
In the first embodiment, the sensor 123a is used to detect the position of the third lens group 103 and the current position of the third lens group 103, which are stored before the motor is stopped, between the stop and restart of the voice coil motor. An example is shown in which it is determined whether or not the holding operation is performed based on whether or not the position change of the third group lens 103 is equal to or greater than a predetermined value.
In the second embodiment, as another determination method, a method of stopping and restarting energization of the coil 118a of the voice coil motor based on a change in the camera posture based on information obtained from the posture determination unit 416 is shown. .
That is, the driving mechanism of the third group lens 103 according to the first embodiment uses a position detection unit that detects the position of the third group lens 103 as a state detection unit that detects a change in the state related to the position or movement. . On the other hand, in the second embodiment, the posture sensor 415 and the posture determination unit 416 are used as the state detection unit, and it is determined whether or not the holding operation is performed based on these detection results.
The second embodiment has the same configuration as the first embodiment except that the contents of the operation are partially different. Therefore, the same reference numerals are given to the portions that perform the same functions as those in the first embodiment described above, and repeated descriptions are omitted as appropriate.

FIG. 8 is a flowchart showing the focus operation of the second embodiment.
Since the basic operation flow of the second embodiment is the same as that of the first embodiment, only different parts from the first embodiment will be described here.
S1 to S8 are the same as in the first embodiment.
In S31, the posture of the camera immediately before stopping the voice coil motor is stored using the posture sensor 415 and the posture determination unit 416.
S32 is the same as S10 of the first embodiment.
In S33, the holding energization determination routine is started as in the first embodiment. The holding energization determination routine is a routine for determining whether or not energization of the voice coil motor is necessary to hold the position of the third group lens 103. However, in the second embodiment, the determination method is different from that of the first embodiment.
Specifically, when it is determined in S34 that there has been a change in the camera posture (camera upward or downward direction) that affects the driving direction of the voice coil motor (longitudinal direction of the guide shaft 121), the holding energization to the voice coil motor is performed. Start.
S35 to S39 are the same as S16 to S20 of the first embodiment.

  As described above, in this embodiment, the holding operation is performed only when the posture of the camera is changed. Therefore, the time for holding and energizing the coil 118a of the voice coil motor can be reduced. Therefore, the position of the third group lens 103 can be held at a specific position while reducing power consumption.

(Deformation)
The present invention is not limited to the embodiment described above, and various modifications and changes are possible, and these are also within the scope of the present invention.
(1) In each of the embodiments, the third group lens 103 that is a focus lens has been described as an example of a holding operation. However, lenses other than the focus lens may be used. In addition to a lens that provides a refractive action, an optical member that exerts other actions on light may be used. For example, it may be a mirror that reflects light, or may be a light blocking member such as a shutter or a diaphragm that blocks light, or various types that deflect light, diffract light, or partially transmit light. It may be a filter.

(2) In each of the embodiments, the contrast AF method that performs so-called hill-climbing driving for obtaining the in-focus position while performing the wobbling operation of the third group lens 103 that is a focus lens has been described as an example. Other AF methods such as a phase difference AF method may be used.

(3) In 2nd Embodiment, the example which uses an inclination sensor for the attitude | position determination of the camera was shown. Not limited to this, for example, the change in posture by detecting the tilt using the change in the control amount of the third lens group (for example, the integral control amount that increases or decreases due to the gravitational load of the camera posture calculated by the focus drive control unit) May be detected to determine whether to perform the holding operation. In this way, it is not necessary to install an inclination sensor or the like, and no space for component placement is required, and a smaller device can be obtained.

(4) In each embodiment, the camera in which the lens barrel is integrally attached to the camera body has been described as an example. However, the present invention is not limited to this. For example, an interchangeable lens that is detachable from the camera body. It may be a lens barrel of the form.

  Note that the first embodiment, the second embodiment, and the modified embodiments can be used in appropriate combination, but detailed description thereof is omitted. Further, the present invention is not limited by the embodiments described above.

1 is an exploded perspective view around a lens barrel of a first embodiment of a camera using an optical member control device according to the present invention. It is a block diagram which shows the camera using the optical member control apparatus by this invention. FIG. 3 is an exploded perspective view showing a driving mechanism of a third group lens 103 and an image sensor base plate 109. FIG. 6 is a perspective view showing a state in which the drive mechanism of the third group lens 103 and the image sensor base plate 109 are assembled. It is a figure which shows the example of the output of the periodic waveform obtained from the light receiving element of the sensor 123a. It is a flowchart which shows the focus operation | movement of 1st Embodiment. It is a state transition diagram which shows the change of stop and restart of the voice coil motor of 1st Embodiment. It is a flowchart which shows the focus operation | movement of 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 1st group lens 102 2nd group lens 103 3rd group lens 104 Image pick-up element 105 1st lens barrel 105a Follower pin 106 2nd lens barrel 106a Follower pin 107 3rd lens barrel 108 Shutter and aperture unit 109 Image pick-up element base plate 110 Low pass filter 111 Cover barrel 112 Drive cylinder 112a Gear part 112b Straight groove 113 Drive gear 114 Zoom motor 115 Fixed cylinder 115a Feed cam 115b Feed taper cam 115c Straight groove 116 Moving cam cylinder 116a Follower pin 116b Drive pin 116c, 116d Taper cam 117c Projection part 117b Projection part 117b Straight groove 118a Coil 118b Magnet 118c Yoke 119 Flexible substrate 120 Fixing member 121 Guide shaft 122 Support member 23a sensor 123b scale 124 elastic holding member 401 zoom drive control unit 402 shutter / aperture unit drive control unit 403 shift lens drive control unit 404 focus drive control unit 405 imaging signal processing unit 406 video signal processing unit 407 display unit 408 display control unit 409 Posture information control unit 410 Control unit 411 Power supply unit 412 External input / output terminal unit 413 Operation unit 414 Storage unit 415 Posture sensor 416 Posture determination unit

Claims (13)

An optical member that constitutes a part of the photographing optical system and changes a focal state by moving along the optical axis of the photographing optical system ;
A drive unit for driving the optical member;
The focus position of the optical member to be in-focus state is stored as the stop position in focusing operation, a drive control unit for performing control by controlling the driving unit moves the optical member to the stop position,
A state detecting unit for detecting a change in a state related to the position or movement of the optical member;
With
The drive control unit stops the optical member at the stop position by stopping energization of the drive unit when it is determined in the focus adjustment operation that the position of the optical member is the in- focus position . together is, whether when to resume the power supply to the drive unit determines the detection result by the state detection unit have rows holding operation for holding the optical member to the stop position, performs a focusing operation again Determining whether to continue the holding operation of the optical member when the focus adjustment operation is not performed,
An optical member control device. The state detection unit includes a position detection unit that detects a position of the optical member,
The drive control unit determines whether to perform the holding operation by comparing a difference between the stop position at which the optical member is stopped and the current position of the optical member detected by the position detection unit with a threshold value. To do,
The optical member control device according to claim 1. The state detection unit includes a posture determination unit that determines what state the posture of the optical member control device is in,
The drive control unit determines whether to perform the holding operation based on a determination result of the posture determination unit;
The optical member control device according to claim 1 or 2, wherein The posture determination unit determines the posture based on an output from the posture sensor or a change in a control amount by the drive control unit;
The optical member control device according to claim 3. The drive unit uses a voice coil motor;
The optical member control apparatus according to any one of claims 1 to 4, wherein A lens barrel comprising the optical member control device according to any one of claims 1 to 5 . The optical member control device according to any one of claims 1 to 5 ,
An imaging unit that captures an image obtained through the optical member;
An imaging apparatus comprising: The drive control unit determines whether to perform the holding operation by comparing a difference between the stop position at which the optical member is stopped and the current position of the optical member detected by the position detection unit with a threshold value. , causing the threshold is changed in accordance with the depth of field,
The imaging apparatus according to claim 7 . The drive control unit performs the holding operation when the imaging unit performs imaging;
The image pickup apparatus according to claim 7 or 8 , wherein: The imaging unit performs imaging after the holding operation is stabilized after the drive control unit starts the holding operation;
The imaging apparatus according to claim 9 . It has a display unit that displays captured images,
When the display unit does not display the captured image, the drive control unit stops the optical member using the preset position as the stop position, and determines the detection result by the state detection unit to perform the drive Moving the optical member to the stop position to perform the holding operation when resuming energization to the unit ,
The imaging device according to any one of claims 7 to 10, wherein An optical member that constitutes a part of the photographing optical system and changes a focal state by moving along the optical axis of the photographing optical system;
A drive unit for driving the optical member ;
A drive control unit that stores a focus position of the optical member that is in a focused state in a focus adjustment operation as a stop position, and controls the drive unit to move the optical member to the stop position;
A state detecting unit for detecting a change in a state related to the position or movement of the optical member;
A control method executed by an optical member control device comprising:
In the drive control of the optical member, when the position of the optical member is determined to be the in-focus position by a focus adjustment operation, the drive control unit stops energization to the drive unit, thereby the optical member Performing a holding operation for holding the optical member at the stop position when the detection result by the state detection unit is determined and the energization to the drive unit is resumed.
A determination step of determining whether to perform the focus adjustment operation again after the holding operation;
A step of determining whether or not to perform the holding operation of the optical member when it is determined that the focus adjustment operation is not performed in the determination step;
A control method for an optical member control device. An optical member that constitutes a part of the photographing optical system and changes a focal state by moving along the optical axis of the photographing optical system;
A drive unit for driving the optical member ;
A drive control unit that stores a focus position of the optical member that is in a focused state in a focus adjustment operation as a stop position, and controls the drive unit to move the optical member to the stop position;
A state detecting unit for detecting a change in a state related to the position or movement of the optical member;
A control method executed by an imaging apparatus comprising:
In the drive control of the optical member, when the position of the optical member is determined to be the in-focus position by a focus adjustment operation, the drive control unit stops energization to the drive unit, thereby the optical member Performing a holding operation for holding the optical member at the stop position when the detection result by the state detection unit is determined and the energization to the drive unit is resumed.
A determination step of determining whether to perform the focus adjustment operation again after the holding operation;
A step of determining whether or not to perform the holding operation of the optical member when it is determined that the focus adjustment operation is not performed in the determination step;
A method for controlling an image pickup apparatus.

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