JP7230942B2 - Lens barrel and camera - Google Patents

Description

The present invention relates to a lens barrel and an imaging device.

When controlling the lens drive by feedback control, the deviation from the target position and speed becomes large due to sudden load fluctuations when static friction changes to dynamic friction at the start of movement, and changes in the controlled object due to temperature changes. As a result, the positioning accuracy deteriorates.

In Japanese Unexamined Patent Application Publication No. 2002-100002, a guide bar that is slidably fitted to a focus lens holder and guides the focus lens in the optical axis direction is rotated in the circumferential direction or vibrated in the optical axis direction to drive the lens. Changes in the frictional load are suppressed by keeping the frictional load applied in the process always in a state of dynamic friction.

However, since such a conventional technique requires a drive device for the guide bar, an increase in cost, size, and weight is expected, and there remains a problem regarding changes in controlled objects other than friction.

Japanese Patent Application Laid-Open No. 2012-203019

SUMMARY OF THE INVENTION It is an object of the present invention to provide a lens barrel and imaging device that allows quick and accurate movement of the lens toward a target position.

In order to achieve the above object, the lens barrel according to the first aspect of the present invention includes:
an imaging optical system (102, 104, 106, 152, 108);
a driving unit (10) for moving in a predetermined direction a lens holder (154) holding at least a part (152) of a lens group constituting the photographing optical system;
A lens barrel having a control section (30) for sending a control signal to the drive section and controlling the drive section,
The control unit (30)
a first manipulated variable output unit (18) that outputs a first manipulated variable for performing feedback control;
a second manipulated variable output unit (20) for outputting a second manipulated variable required to hold the lens holder at a predetermined position;
and a manipulated variable selector (16) for selecting one of the first manipulated variable and the second manipulated variable.

The second manipulated variable output section (20) may have a storage section that stores, as the second manipulated variable, the manipulated variable at a first time when the lens holder (154) is held at a fixed position. .

The first time (t0) is
is a time before the current second time (t1, t2),
When the time from the first time to the second time is equal to or longer than the predetermined time (α), the manipulated variable selector (16) selects the first manipulated variable instead of the second manipulated variable. may be configured to select

first attitude information of the lens barrel (100) at the first time (t0);
When the difference from the second position information of the lens barrel at the current second time (t1, t2) is equal to or greater than a predetermined value, the operation amount selector (16) selects Alternatively, the first manipulated variable may be selected instead.

A lens barrel according to a second aspect of the present invention comprises

an imaging optical system (102, 104, 106, 152, 108);
a driving unit (10) for moving in a predetermined direction a lens holder (154) holding at least a part (152) of a lens group constituting the photographing optical system;
A lens barrel having a control section (30) for sending a control signal to the drive section and controlling the drive section,
The control unit (30)
a first manipulated variable output unit (18) that outputs a first manipulated variable for performing feedback control;
a second manipulated variable output unit (20) for outputting a second manipulated variable (FIG. 10) required to hold the lens holder at a predetermined position from the posture data of the lens holder;
and a manipulated variable selector (16) for selecting one of the first manipulated variable and the second manipulated variable.

The operation amount selector (16) selects one of the first operation amount and the second operation amount at timing (t2) when the depth of field of the photographing optical system is within a predetermined range. may

When autofocus driving the lens group by the drive unit,
During initial driving for returning the lens group to an initial position and during search driving for searching the lens group, the operation amount selection unit selects only the first operation amount,
At the time of the focusing operation of moving the lens group to the in-focus position detected by the searching operation, the operation amount selection section selects one of the first operation amount and the second operation amount. good too.

The manipulated variable selector may select one of the first manipulated variable and the second manipulated variable based on a result of comparing the first manipulated variable and the second manipulated variable.

The imaging device (300) according to the present invention is
an imaging optical system (102, 104, 106, 152, 108);
a driving unit for moving in a predetermined direction a lens holder (154) holding at least a part (152) of a lens group constituting the photographing optical system;
a control unit (30, 40) for sending a control signal to the driving unit and controlling the driving unit,
The control unit (30, 40)
a first manipulated variable output unit (18) that outputs a first manipulated variable for performing feedback control;
a second manipulated variable output unit (20) for outputting a second manipulated variable required to hold the lens holder at a predetermined position;
and a manipulated variable selector (16) for selecting one of the first manipulated variable and the second manipulated variable.

In the above description, in order to explain the present invention in an easy-to-understand manner, the present invention is described in association with the reference numerals of the drawings showing the embodiments, but the present invention is not limited thereto. The configurations of the embodiments described later may be modified as appropriate, and at least a part of them may be replaced with other configurations. Furthermore, constituent elements whose arrangement is not particularly limited are not limited to the arrangement disclosed in the embodiments, and can be arranged at positions where their functions can be achieved.

FIG. 1 is a schematic diagram of a camera (photographing device) according to one embodiment of the present invention. 2A is a front view of the autofocus section of the camera shown in FIG. 1, and FIG. 2B is an enlarged sectional view of the autofocus section of the camera shown in FIG. 3 is a perspective view of the autofocus section shown in FIG. 2. FIG. FIG. 4 is a flow chart showing an example of control in the control block diagram of the camera shown in FIG. FIG. 5 is a flow chart showing another example of control. FIG. 6 is a flow chart showing still another example of control. FIG. 7 is a flowchart showing yet another example of control. FIGS. 8A and 8B are flowcharts showing still another example of control. FIG. 9 is a flow chart showing still another example of control. FIG. 10 is a graph showing the relationship between the posture and holding force for obtaining the second manipulated variable shown in FIG. FIG. 11A is a time chart showing the relationship between the target position of the camera and the actual lens position according to one embodiment of the present invention, and FIG. 11B is a time chart showing the relationship between the target speed and the actual lens speed. 11(C) is a time chart of the operation amount. FIG. 12A is a time chart showing the relationship between the target camera position and the actual lens position when the movement distance is shorter than that of FIG. 12A, and FIG. 12B is the target speed and the actual lens speed. , and FIG. 12C is a time chart of the amount of operation. FIG. 13A is a time chart showing the relationship between the camera target position and the actual lens position according to another embodiment of the present invention, and FIG. 13B shows the relationship between the target speed and the actual lens speed. Time chart, Fig. 13(C) is a time chart of the amount of operation.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described based on embodiments shown in the drawings.
1st embodiment

A camera 300 as an imaging device according to an embodiment of the present invention shown in FIG. 1 has a lens barrel 100 and a camera body 200 . In the following embodiments, a lens-interchangeable single-lens reflex camera in which the lens barrel 100 is detachably attached to the camera body 200 will be described as an example, but the present embodiment is not limited to this. For example, it may be a compact camera in which the lens barrel and the camera body are integrated, or a mobile device with a camera.

The lens barrel 100 includes, from the subject side along the optical axis L, a first lens section 102, a second lens section 104, a third lens section 106, a focus lens section 150 as a fourth lens section, and a fifth lens section. 108 , and guides light from the object side to an imaging unit (not shown) of the camera body 200 . The first lens unit 102, the second lens unit 104, the third lens unit 106, the focus lens unit 150, and the fifth lens unit 108 move parallel or perpendicular to the optical axis L to perform zoom adjustment and focus adjustment. , blur correction, etc.

In the following description, the axis parallel to the optical axis L is the Z-axis, and the plane perpendicular to the Z-axis is the plane containing the X-axis and the Y-axis. The X-axis and Y-axis are perpendicular to each other.

As shown in FIGS. 2A and 2B, the focus lens section 150 has a focus lens group 152 held by a lens holder 154 . The focus lens group 152 is arranged substantially at the center of the lens holder 154 on the XY plane.

As shown in FIG. 2A, in the lens holder 154, a first VCM 156, a first guide portion 172, a second VCM 164, and a second guide portion 174 are arranged in this order clockwise along the circumferential direction. The first VCM 156, the first guide portion 172, the second VCM 164, and the second guide portion 174 are arranged at substantially equal angles in the circumferential direction.

The first VCM 156 and the second VCM 164 are arranged on both sides in the Y-axis direction including substantially the center of the focus lens group 152 . The distance from approximately the center of the focus lens group 152 to the first VCM 156 is approximately the same as the distance from approximately the center of the focus lens group 152 to the second VCM 164 .

The first VCM 156 and the second VCM 164 are electromagnetic actuators, and the lens holder 154 is relatively movable along the optical axis L by the first VCM 156 and the second VCM 164, as shown in FIG. 2(b).

The first guide portion 172 and the second guide portion 174 are arranged on both sides in the X-axis direction including substantially the center of the focus lens group 152 . The distance from approximately the center of the focus lens group 152 to the first guide portion 172 and the distance from approximately the center of the focus lens group 152 to the second guide portion 174 are approximately the same.

As shown in FIG. 3, the first guide portion 172 is slidably held by a first guide bar 176 extending in the Z-axis direction, and the second guide portion 174 is slidably held by a second guide bar 178 extending in the optical axis L direction. slidably held in the

The first guide portion 172 has a bearing portion, and by inserting the first guide bar 176 into the bearing portion, the first guide portion 172 can be smoothly moved along the first guide bar 176 parallel to the optical axis L direction. It is made to slide.

As shown in FIG. 2A, the second guide portion 174 has an elongated hole elongated in the X-axis direction. The second guide bar 178 is fitted in the elongated hole of the second guide portion 174 so as to slide smoothly along the optical axis L direction and have play in the X axis direction.

Since the second guide bar 178 is fitted into the second guide portion 174 with play in the X-axis direction, the lens holder 154 can be moved along the optical axis L smoothly. In addition, while the lens holder 154 moves along the optical axis L direction, the second guide part 174 can prevent the lens holder 154 from rotating with respect to the optical axis L.

As shown in FIG. 3, the lens holder 154 is provided with a protrusion 180 projecting radially outward between the first guide portion 172 and the first VCM 156 . The projection 180 moves in the direction of the optical axis L together with the lens holder 154, and the detection sensor 182 detects the position of the projection 180, for example. That is, the detection sensor 182 is composed of, for example, a range sensor or the like that detects the positional coordinates of the lens holder 154 .

As shown in FIGS. 2(a) and 2(b), the first VCM 156 has a first drive coil 158, a first drive magnet 160, and a first yoke 162. FIG. The first yoke 162 is U-shaped in the cross section shown in FIG. 2(b) and has an outer yoke portion 162A and an inner yoke portion 162B parallel to the XZ plane. The outer yoke portion 162A and the inner yoke portion 162B are integrally connected at one end in the optical axis L direction by a connecting portion 162C. The other ends of the outer yoke portion 162A and the inner yoke portion 162B are attached to the fixed portion 110 of the lens barrel 100. As shown in FIG.

The first driving magnet 160 is arranged so as to be covered by the first yoke 162 and fixed inside the outer yoke portion 162A of the first yoke 162 by screwing, bonding or other methods. The first driving magnet 160 is magnetized along the Y-axis, and together with the first yoke 162 constitutes a magnetic circuit that generates a magnetic field along the Y-axis.

The first drive coil 158 is attached to the lens holder 154 and arranged so that current flows in a direction perpendicular to the magnetic field generated between the first drive magnet 160 and the first yoke 162 . That is, the magnetic circuit composed of the first driving magnet 160 and the first yoke 162 causes the first driving coil 158 arranged in the first yoke 162 to generate a magnetic field in the Y-axis direction. The first drive coil 158 is arranged so that current flows along the X-axis, which is perpendicular to the Y-axis.

By applying a current to the first drive coil 158, the lens holder 154 is driven by the Lorentz force generated in the first drive coil 158, and the focus lens group 152 moves along the optical axis L (Z-axis). .

The second VCM 164 has a second drive coil 166 , a second drive magnet 168 and a second yoke 170 . The second VCM 164 has the same configuration as the first VCM 156 described above, so its description is omitted.

Next, a control block diagram for moving the focus lens unit 150 along the optical axis L will be described with reference to FIG. In this embodiment, the lens barrel 100 is provided with the lens side control section 30, the camera body 200 is provided with the body side control section 40, and the control sections 30 and 40 are connected via the communication section 44. data communication between

The drive unit 10 shown in FIG. 1 corresponds to the first drive coil 158 of the first VCM 156 and the second drive coil 166 of the second VCM 164 described above with reference to FIGS. The drive unit 10 is controlled by the driver 14 of the control unit 30 . The driver 14 controls the drive unit 10 based on the data of the operation amount selected by the operation amount selection unit 16 to move the focus lens unit 150 to a predetermined position in the optical axis direction to perform a focusing operation.

The operation amount selection unit 16 receives data from the position detection unit 12, the first operation amount output unit 18, the second operation amount output unit 20, and the attitude sensor 22 as necessary, determines a predetermined condition, 14, the required manipulated variable data is sent. The position detection unit 12 is, for example, the detection sensor 182 shown in FIG. 3, and is capable of detecting the Z-axis direction position of the lens holder 154 that moves in the Z-axis direction. Data regarding the Z-axis direction position of the lens holder 154 detected by the position detection unit 12 is input to the first operation amount output unit 18 and, if necessary, to the operation amount selection unit 16 .

The first operation amount output unit 18 generates first operation amount data, which is feedback control data, based on, for example, lens movement command data output from the body-side control unit 40 and position data from the position detection unit 12. Output to the manipulated variable selector 16 . The first manipulated variable data is data for controlling the drive unit 10 using the driver 14 based on feedback control, and is shown in FIGS. 11(C), 12(C) and 13(C), for example. , which can be considered as the amount of current applied to the drive unit 10, the power, or the duty for driving.

The first manipulated variable data is the target position of the lens (lens holder 154) shown in FIGS. position) and command data to the driver 14 that fluctuates with time. 11B, 12B, and 13B, and the actual speed of the lens (lens holder 154). It can also be said that the command data to the driver 14 varies with time.

The type of feedback control performed by the first manipulated variable output unit 18 is not particularly limited, and may be either feedback control using speed deviation or feedback control using position deviation. is also not limited.

In the second operation amount output section 20, the command data from the body side control section 40, the divergence data between the target position and the actual lens position from the first operation amount output section 18, or the camera attitude from the attitude sensors 22 and 42 Based on the data or the like, the second manipulated variable data is generated and output to the manipulated variable selector 16 . The second manipulated variable output section 20 performs control different from the feedback control performed by the first manipulated variable output section 18 .

The second operation amount data is a drive signal output from the driver 14 to the drive unit 10 in order to fix and hold the lens holder 154 at a predetermined position in the Z-axis direction. It is data that changes depending on the internal structure of For example, when the lens barrel 100 of the camera 300 is directed vertically upward or downward, and the lens holder 154 is stopped and held at a predetermined position in the Z-axis direction, the gravity of the lens holder 154 and the lens group 152 may It is necessary to output the manipulated variable data from the driver 14 to the drive unit 10 so that the opposing force acts on the drive unit 10 . The manipulated variable data required at that time is referred to as second manipulated variable data in the present embodiment.

The reason why the second manipulated variable data changes depending on the environmental temperature is, for example, that the viscosity of the bearing grease used for the guides 172 and 274 shown in FIG. This may be due to changes in the holding force for holding in place. Furthermore, the reason why the second manipulated variable data changes due to the internal structure of the lens barrel is, for example, that a spring force is constantly acting on the lens holder 154 .

In this embodiment, the orientation sensors 22 and 42 shown in FIG. 1 are not particularly limited as long as they can detect the orientation of the camera 300 (including the lens barrel 100 and the camera body 200). It consists of an acceleration sensor, etc. In FIG. 1, the lens side control section 30 is configured with only the driver 14, the operation amount selection section 16, the first operation amount output section 18, and the second operation amount output section 20. Unit 30 may have other control blocks. Further, although the driver 14, the manipulated variable selector 16, the first manipulated variable output section 18, and the second manipulated variable output section 20 are illustrated as control circuits, they do not necessarily have to be control circuits. It may be a program that controls the

Next, an example of the operation of the control section 30 shown in FIG. 1 will be described based on the flowchart shown in FIG. For example, as shown in FIG. 4, when the control starts, the position detector 12 detects the Z-axis direction position of the lens holder 154 shown in FIG. 1 in step S1. More specifically, when command data from the body-side control unit 40 shown in FIG. ) is detected how far the actual lens position (hereinafter also referred to as the actual lens position) is from the target position of the lens in the Z-axis direction shown in FIG.

Next, in step S2 shown in FIG. 4, the manipulated variable selector 16 or the first manipulated variable output section 18 shown in FIG. 1 determines whether the actual lens position satisfies a predetermined condition. In this embodiment, in step S2 shown in FIG. 4, it is determined whether or not the actual lens position shown in FIG. 11A or 12A has already reached the target position. If the target position has already been reached, go to step S6 shown in FIG. 4, otherwise go to steps S3 to S5 and repeat normal feedback control.

That is, in step S3, for example, the first manipulated variable output unit 18 shown in FIG. ) or data of the first manipulated variable shown in FIG.

In step S4 shown in FIG. 4, the manipulated variable selection unit 16 shown in FIG. 1 selects the data of the first manipulated variable, and in step S5 shown in FIG. , the driver 14 drives the driving section 10 with a control signal based on the data of the first manipulated variable. Steps S1 to S5 are repeated to perform feedback control until the conditions in step S2 are satisfied.

In step S2 shown in FIG. 4, if the condition is satisfied, for example, if the actual lens position shown in FIG. 11A or 12A reaches the target position, the second operation amount output unit 20 generates data of the second manipulated variable and outputs it to the manipulated variable selector 16 . The second manipulated variable output unit 20 generates the data of the second manipulated variable by, for example, estimating the lens holding force.

The method of estimating the lens holding force is not particularly limited, but the second manipulated variable output unit 20 calculates from data such as the environmental temperature of the camera 300, the internal structure of the lens barrel 100, the age of the camera 300, the attitude of the camera, etc. can be estimated by Alternatively, as will be described later, before a predetermined time α from the present time, data on the amount of operation corresponding to the actual holding force required to stop and hold the lens holder is stored in storage means such as a memory, The manipulated variable data may be estimated as the holding force at the present time.

The estimated holding force used as data for the second manipulated variable is the holding force required to stop and hold the lens holder 154 shown in FIG. ), it is a predetermined value (constant value that does not depend on time) within the range β of the holding force considering static friction, and is a value close to the manipulated variable β1 that balances the force acting on the lens holder. may not necessarily match. It should be noted that the operation amount β1 that balances the forces acting on the lens holder is ideally close to 0 if the optical axis of the lens barrel 100 is horizontal, and even if the operation amount is 0, the lens holder stops without moving in the Z-axis direction.

In any case, the second manipulated variable output section 20 shown in FIG. 1 outputs the estimated holding force as the second manipulated variable data to the manipulated variable selector 16 (step S6). The manipulated variable selector 16 outputs the second manipulated variable data instead of the first manipulated variable data to the driver 14 on the condition that the condition in step S2 is satisfied (step S6). 11 and 12, the switching timing t1 is the point in time when the actual lens position reaches the target position in this embodiment. Control based on the data of the second manipulated variable is performed.

In the lens barrel 100 and the camera 300 according to the present embodiment, the control unit 30 or the control unit 40 shown in FIG. and have Therefore, in the present embodiment, as shown in FIGS. 11 and 12, at a predetermined timing t1 such as when the actual lens position reaches the target position, the control operation output from the driver 14 shown in FIG. The amount can be switched from the first manipulated variable to the second manipulated variable.

As described above, the first manipulated variable is a controlled variable that changes with time based on feedback control. As shown in FIGS. , the lens position may greatly overshoot the target position, as indicated by the dotted line after t1 in FIGS. 11 and 12 .

Note that the example of FIG. 11 shows driving waveforms that may occur when the driving force of the driving unit 10 shown in FIG. 1 for driving the lens holder 154 is weakened. When the driving force becomes weaker than expected due to environmental changes such as temperature and product variations, the speed deviation during acceleration and deceleration increases. was likely to overshoot from On the other hand, in the present embodiment, as shown by the solid line, since the first manipulated variable is switched to the second manipulated variable, the possibility of overshooting is reduced, and the lens position reaches the target position in a short time. can be brought closer.

The example of FIG. 12 shows drive waveforms when the lens speed greatly overshoots the target speed when the lens holder 154 is moved by a short distance or when static friction increases due to deterioration of the sliding surface. In this case, since the lens position reaches the target position at timing t1 before the lens speed converges to the target speed, there is a high possibility that the lens position will overshoot from the target position.

On the other hand, in the present embodiment, as shown by the solid line, since the first manipulated variable is switched to the second manipulated variable at timing t1, the possibility of overshooting is reduced, and the lens position can be achieved in a short time. It becomes possible to approach the position to be. That is, in the present embodiment, at timing t1 when it is determined that the lens holder 154 has overshot the target position during movement, the operation amount is not the feedback control calculation value (first operation amount), but the estimated movable portion holding force. By setting the equivalent (second manipulated variable), the lens holder 154 can be stopped at or very close to the target position more quickly.

11 and 12 , in the course of deceleration during movement of the lens holder 154, the first operation amount based on the holding force estimated from the first operation amount, which is feedback control, is used. By switching to two operation amounts, it is possible to stop the lens more quickly than before, and to suppress the overshoot of the lens position. That is, in this embodiment, the lens can be quickly and accurately moved toward the target position.
Second embodiment

The lens barrel and camera according to the present embodiment differ from the lens barrel 100 and the camera 300 according to the first embodiment only in the parts described below, and the other configurations are the same as those of the first embodiment. They are similar and have similar effects.

In this embodiment, the timing of switching from the first manipulated variable to the second manipulated variable using the first manipulated variable output unit 18, the second manipulated variable output unit 20, or the manipulated variable selector 16 shown in FIG. , at timing t2 shown in FIG.

In the embodiment shown in FIG. 13, instead of switching from the first operation amount to the second operation amount when the actual lens position reaches the target position, the operation amount selector shown in FIG. 16 switches from the first manipulated variable to the second manipulated variable.

The switching timing (or the timing for determining whether or not switching is necessary) t2 by the operation amount selection unit 16 is preferably at least before the actual lens position reaches the target position, and may be set during or after the target speed is decelerated. is the timing. Specifically, for example, the timing t2 is determined as follows.

To move the lens holder 154 shown in FIG. 1 in the Z-axis direction to perform the autofocusing operation, for example, contrast AF, phase AF, or other AF methods are available. In any case, since the lens holder 154 is moved and stopped, the configuration of the present invention can be applied regardless of the AF method.

For example, in the case of contrast AF, an initial drive operation to return the lens group 152 to the initial position (may not exist), a search drive operation to search the lens group 152, and a search operation to detect the lens group 152. and a focusing operation to move to an in-focus position. In the case of the initial drive operation and the search operation, it is not necessary to stop the lens group 152 accurately. The selector 16 may select either the first manipulated variable or the second manipulated variable.

In this embodiment, the first operation amount is switched to the second operation amount at timing t2 described below during or after the movement deceleration of the lens holder 154 during the focusing operation. When the in-focus position is determined by the search operation described above, for example, the control unit 40 or the control unit 30 shown in FIG. 1 sets the target position shown in FIG. A target speed for movement is set as shown in FIG. 13(B). In the focusing operation, since the movement distance is short, the actual lens speed easily exceeds the target speed as shown in FIG. 13(B).

In this embodiment, the range γ of the depth of focus (depth of field) corresponding to the target position is calculated by one of the control units 30 and 40, and the lower limit position of the range γ (before the target position), or The timing t2 is detected when the lens position reaches a position corresponding to any position between the target position and the lower limit position of the depth of focus γ, and at the timing t2, the selection unit 16 shown in FIG. I do.

Conventionally, when the lens holder 154 is moved by a short distance, the lens speed greatly overshoots the target speed as shown in FIG. 13(B). It overshoots the target position greatly.

On the other hand, in the present embodiment, as indicated by the solid line, the first manipulated variable is switched to the second manipulated variable at the timing t2. It becomes possible to approach the position to be. That is, in the present embodiment, at the timing t2 corresponding to the lower limit position of the range γ of the depth of focus (depth of field) corresponding to the target position, the operation amount is not the feedback control calculation value (first operation amount), The lens holder 154 can be stopped more quickly at or near the target position by setting the estimated moving part holding force equivalent (second operation amount).
Third embodiment

The lens barrel and camera according to this embodiment differ from the lens barrel 100 and camera 300 according to the first or second embodiment only in the following parts, and other configurations are as follows. It is the same as the first embodiment or the second embodiment, and has the same effect.

In this embodiment, the control units 30 and 40 shown in FIG. 1 perform control of the flow charts shown in FIGS. As shown in FIG. 5, when the control starts, in step S11, the first manipulated variable output unit 18 shown in FIG. 1 calculates the first manipulated variable based on feedback control.

Next, in step S12 shown in FIG. 5, controller 30 or controller 40 detects the speed of lens holder 154 from position data detected by position detector 12 shown in FIG. 1, for example. A sensor other than the position detector 12 may be used to detect the speed in step S12.

Next, in step S13 shown in FIG. 5, based on the speed detected in step S12, the controller 30 or 40 determines whether the speed of the lens holder 154 in the Z-axis direction is zero. If the speed is 0, the process advances to step S14 to update the second manipulated variable stored in the memory (inside the control unit 30) as a storage unit (not shown in FIG. 1), At step S15, the current time t0 at that timing is stored in the memory. After that, in step S16, the control unit 30 or 40 raises a flag that enables setting of the second manipulated variable and stores it in the memory.

For example, in FIGS. 11 to 13, if the current speed is determined to be 0 at any timing t0 before the lens holder 154 is moved to the target position, the first operation amount at that timing t0 is is stored in the memory in step S14 as data of the second manipulated variable to be used at timing t1 or t2 thereafter. This is because the data of the first manipulated variable at timing t0 can be estimated as the holding force at speed 0. Also, in step S15, the timing (time) t0 at speed 0 is stored in the memory.

In step S13, if the current speed is not 0, the holding force cannot be estimated. store in

Thereafter, in step S21 shown in FIG. 6, position detection similar to the position detection in step S1 shown in FIG. 4 is performed. Next, in step S22, the same determination as in step S2 shown in FIG. 4 is made. However, the timing of determination is not limited to the timing t1 shown in FIGS. 11 and 12, and may be the timing t2 shown in FIG.

For example, at timing t1 shown in FIGS. 11 and 12, when it is determined that the lens position has reached the target position, the process proceeds from step S22 to step S26 shown in FIG. 6, otherwise step S23. go to. Alternatively, when it is determined that the lens position has reached between the lower limit position of the range γ of the depth of focus and the target position at timing t2 shown in FIG. 13, the process proceeds from step S22 to step S26 shown in FIG. Otherwise, go to step S23.

In step S26, the flag stored in the memory in step S16 or step S17 shown in FIG. 5 is read to determine whether or not the second manipulated variable can be output. Although the entity that makes the determination is not particularly limited, it is, for example, the manipulated variable selector 16 shown in FIG. If it is determined in step S26 that the output of the second manipulated variable is possible, in step S27 the manipulated variable selector 16 shown in FIG. Data of the second operation force as a certain estimated holding force is received, and the second operation amount is output to the driver 14 in step S25. The output of the second manipulated variable is after timing t1 or t2 in FIGS.

In step S26 shown in FIG. 6, when it is determined that the second manipulated variable cannot be output, the second manipulated variable is not selected even after timing t1 or t2, and steps S23 to S25 are executed. Feedback control based on the first manipulated variable is performed. Since steps S23 to S25 are the same as steps S3 to S5 shown in FIG. 4, description thereof will be omitted.

FIG. 7 is a further modification of the third embodiment. In step S31, the control unit 30 or 40 shown in FIG. 1 determines whether the current time, that is, the timing t1 or t2 shown in FIGS. 11 to 13 is smaller than t0+α. α indicates a predetermined elapsed time from time t0 shown in FIGS. 11 to 13, and is not particularly limited, but is preferably set within a range of 0.01 to 2 seconds, eg, 1 second.

If the current time t1 or t2 is more than the predetermined elapsed time α with respect to the set time t0 of the second manipulated variable updated in step S14 shown in FIG. It is considered that the data of the second manipulated variable (estimated holding force) is outdated. In that case, the process goes from step S31 to step S37 shown in FIG. At step S37, the same operation as at step S17 shown in FIG. 5 is performed.

If the control after timing t1 or t2 is performed based on the data of the second operation amount (estimated holding force) that has become outdated after the predetermined time α or longer, the lens holder can be accurately stopped. Because it can be difficult. For example, at timing t0, the estimated horizontal holding force when the optical axis of lens barrel 100 is horizontal, and the estimated vertical holding force when the optical axis of lens barrel 100 is vertical at timing t1 or t2. is completely different. From this point of view, the predetermined time α is determined, and within the predetermined time α, it is determined within a range in which it is believed that the holding force will not change.

Steps S32 to S36, S38, and S39 shown in FIG. 7 are the same as steps S21 to S27 shown in FIG. 6, so description thereof will be omitted.

By the way, in the present embodiment, in step S13, the stopped state of the lens is determined when the current speed is zero, but the stopped state may be determined by other methods. For example, the stopped state may be determined when the difference between the lens position at the current time and the lens position at the previous time is equal to or less than a predetermined amount.
Fourth embodiment

The lens barrel and camera according to the present embodiment differ from the lens barrel 100 and the camera 300 according to the first to third embodiments only in the parts described below. ˜It is the same as the third embodiment, and has the same effect.

In this embodiment, the control units 30 and 40 shown in FIG. 1 perform control of the flowcharts shown in FIGS. 8A and 8B. As shown in FIG. 8A, when the control starts, steps S41 to S44 and S47 are performed. Since these steps S41 to S44 and S47 are the same as steps S11 to S14 and S17 shown in FIG. 5, description thereof will be omitted.

In this embodiment, after step S44 shown in FIG. 8A, step S45 is performed. In step S45, the controller 30 or 40 shown in FIG. 1 detects the orientation of the lens barrel 100 or the camera body 200 based on the orientation sensor 22 or 42, and saves the orientation data A1 at that point in the memory. do. The timing for storing the posture data A1 is timing t0 shown in FIGS. 11 to 13, for example. Further, the orientation information includes, for example, how many times the optical axis L of the lens barrel 100 is tilted with respect to the horizontal. Next, in step S46 shown in FIG. 8A, the same operation as step S16 shown in FIG. 5 is performed.

Next, in step S50 shown in FIG. 8B, the control units 30 and 40 shown in FIG. Save to memory. Next, in step S51, the control unit 30 (or 40, hereinafter the same) determines whether or not the absolute value of the attitude difference obtained by subtracting the attitude data A2 from the attitude data A1 is within a predetermined allowable range Ath.

If the absolute value of the attitude difference is within the allowable range Ath, go to step S52, otherwise go to step S57. Since step S57 is the same as step S37 shown in FIG. 7, its description is omitted. Also, steps S52 to S56, S58 and S59 shown in FIG. 8B are the same as steps S32 to S36, S38 and S39 shown in FIG. 7, so description thereof will be omitted.

In this embodiment, when the absolute value of the posture difference is within the allowable range Ath at timing t1 or t2 shown in FIGS. It is determined that there is no problem in estimating the holding force after t2, and control is switched to the control based on the second manipulated variable. A specific number of the allowable range Ath is not particularly limited, and may be determined within an angle range of 0 to 10 degrees.
5th embodiment

The lens barrel and camera according to the present embodiment differ from the lens barrel 100 and the camera 300 according to the first to fourth embodiments only in the portions described below, and the rest of the configuration is the same as that of the first camera. ˜It is the same as the fourth embodiment, and has the same effect.

In this embodiment, the control units 30 and 40 shown in FIG. 1 perform control of the flowchart shown in FIG. As shown in FIG. 9, when the control starts, steps S61 to S62 are performed. These steps S61-S62 are the same as steps S1-S2 shown in FIG. 4 or steps S21-S22 shown in FIG. 6, and thus description thereof will be omitted.

In step S62 shown in FIG. 9, when the conditions are satisfied, the process goes to step S66, and when the conditions are not satisfied, the process goes to step S63. Steps S63 to S65 are the same as steps S3 to S5 shown in FIG. 4 or steps S23 to S25 shown in FIG. 6, so description thereof will be omitted.

In step S66, the control units 30 and 40 shown in FIG. 1 acquire posture information based on the posture sensors 22 and 42. In step S67, the second manipulated variable output unit 20 shown in FIG. 1, for example, calculates and generates the second manipulated variable based on the posture information acquired in step S67. The calculation of the second manipulated variable (estimation of the holding force) is obtained by calculation using, for example, the formula shown in FIG. 10 (stored in the memory).

Uh, Uvu, and Uvd shown in FIG. 10 are the holding forces when the optical axis is horizontal, the optical axis is vertically above, and the optical axis is vertically below, respectively. Based on design values such as the weight of the movable portion of the lens holder 154 and the biasing force, the force that balances the design values is calculated and obtained. The holding force Ustop in other postures is determined by the function (Uvu-Uh)*SIN(An)+Uh consisting of Uh, Uvu, and An when the posture information An (angle deg) is greater than 0deg and less than 90deg. When the information An is more than -90deg and less than 0deg, it is obtained by a function (Uvd-Uh)*SIN(An)+Uh consisting of Uh, Uvd and An. Each of the holding forces Uh, Uvu, and Uvd is not limited to one value, and may have multiple values according to changes in state. Changes in the state include, for example, changes in the position of the lens group 152 and other movable lenses, changes in driving force, biasing force, frictional force, gravitational acceleration, etc. due to differences in temperature, shooting location, and the like.

In step S67, the holding force Ustop is estimated from posture data at timings t1 and t2 shown in FIGS. The second manipulated variable output unit 20 shown in FIG. 1 outputs the value as a second manipulated variable to the manipulated variable selector 16 . At step S68, an operation similar to that of step S7 shown in FIG. 4 or step S27 shown in FIG. 6 is performed.

In this embodiment, it is not necessary to update the second manipulated variable at timing t0 shown in FIGS. No need to detect. Also, there is no need to measure the time from timing t0 to t1 or t2.

It should be noted that the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the present invention.

For example, in the above-described embodiment, if the operation amount selector 16 shown in FIG. 1 finds that the first operation amount is smaller than the second operation amount at timing t1 or t2, the operation amount selector 16 Alternatively, the first operation amount may be continuously selected without selecting the second operation amount, and the driver 14 may control the driving section 10 by the first operation amount.

Further, in the above-described embodiment, the autofocus is described in which the lens holder holding the lens group is moved in the direction of the optical axis L. However, it is not limited thereto, and other structures for moving the lens group along the optical axis, or the lens group It can also be applied to a blur correction device that moves in the direction perpendicular to the optical axis. Furthermore, the present invention can also be applied to other structures for moving parts other than the lens group at high speed and stopping them inside the lens barrel or camera body.

DESCRIPTION OF SYMBOLS 10... Drive part 12... Position detection part 14... Driver 16... Operation amount selection part 18... First operation amount output part 20... Second operation amount output parts 22, 42... Posture sensor 30... Lens side control part 40... Body side Control part 44...Communication part 100...Lens barrel 110...Fixed part 150...Focus lens part 152...Focus lens group 154...Lens holder 156...First VCM
158... First drive coil 160... First drive magnet 162... First yoke 164... Second VCM
166... Second drive coil 168... Second drive magnet 170... Second yoke 172... First guide part 174... Second guide part 176... Guide bar 178... Guide bar 180... Projection 182... Detection sensor 200... Camera body 300 Camera

Claims (7)

A lens barrel detachable from a camera body,
a lens holding frame that holds a lens;
a driving unit that moves the lens holding frame to a first position in the optical axis direction by electric power supplied from the camera body;
a detection unit that detects the position of the lens holding frame;
first control for supplying electric power to the drive unit based on the position of the lens holding frame detected by the detection unit and the first position; A control unit that performs a second control that drives at a speed slower than the first control and supplies power to the driving unit,
The control unit
controlling the driving unit by one of the first control and the second control while receiving power from the camera body;
before the movement of the lens holding frame is started, the second control is performed to hold the position of the lens holding frame in the optical axis direction;
The first control is switched to the second control before the lens holding frame reaches the first position, and the electric power to the drive unit is reduced while the first control and the second control are being performed. A lens barrel that never stops supplying. 2. The lens barrel according to claim 1, wherein the driving section generates driving force while the control section is performing the second control. 3. The lens barrel according to claim 2, wherein the driving force varies depending on attitude or temperature. Equipped with a communication unit that can communicate with the camera body,
The lens barrel according to any one of claims 1 to 3 , wherein the control section performs the first control when information for moving the lens is received via the communication section. 5. The lens barrel according to any one of claims 1 to 4 , wherein the lens holding frame is stopped at a predetermined position by the second control. An imaging device comprising the lens barrel according to any one of claims 1 to 5 . A program to be executed by a computer provided in a camera body and a detachable lens barrel,
a driving process of moving a lens holding frame holding a lens to a first position in the optical axis direction by electric power supplied from the camera body;
a detection process for detecting the position of the lens holding frame;
first control for supplying electric power to a driving unit that performs the driving process based on the position of the lens holding frame detected by the detection process and the first position; and holding the position of the lens holding frame in the optical axis direction. a second control for supplying electric power to the driving section by driving at a speed slower than that of the first control, and performing the second control before the lens holding frame reaches the first position. control, and while power is being received from the camera body, either the first control or the second control is performed, and before the movement of the lens holding frame is started, the second control is performed and the lens is a control process of holding the position of the holding frame in the optical axis direction and not stopping the power supply to the drive unit while the first control and the second control are being performed;
A program that causes a computer to run

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