JP2018189828A - Control device, lens barrel, and imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device capable of suppressing the sound occurring in response to the clock frequency, in a manual focus operation using an ultrasonic motor.SOLUTION: A control device (124) includes: acquisition means (124a) for acquiring a signal related to drive of a lens (L3B) from operation means (122); and control means (124b) for controlling the lens on the basis of the signal related to the drive of the lens. The control means sets a second driving speed lower than a first driving speed of the lens, and performs control so that the lens is driven at the second driving speed. The first driving speed is calculated, on the basis of the lens target drive quantity calculated on the basis of the difference between the current position and target position of the lens, and the acquisition cycle of the target drive quantity.SELECTED DRAWING: Figure 1

Description

The present invention relates to a control device that controls the operation of a lens.

  Conventionally, there are optical apparatuses such as a lens apparatus and an imaging apparatus having a focus adjustment function (focus mechanism). The focus mechanism includes a focus detection system that detects a focused state of an object during autofocus (AF), a lens drive system that moves a focusing lens to form a subject image on an image sensor, and a focus detection system And an AF control system that controls the lens driving system. The focus detection system performs focus detection such as a phase difference method and a contrast method. The lens driving system is provided with an encoder for detecting the position of the focusing lens. The AF control system controls the operation of the focusing lens based on the output of the encoder. The focus mechanism includes a manual operation member that is operated by the user during manual focus. In recent years, not only a compact lens and a video lens, but also an interchangeable lens camera lens, an electronic ring for manual focusing is often employed. Further, not only still images but also users who take moving images are increasing, and there is an increasing demand for noise reduction.

  Patent Document 1 discloses an imaging apparatus that controls the drive voltage of an ultrasonic motor in accordance with the operation amount of an operation means that receives an operation by a user. According to the imaging apparatus disclosed in Patent Document 1, it is possible to improve the controllability of the ultrasonic motor and achieve noise reduction. In Patent Document 2, the driving speed of the focus lens is changed according to the operating speed of the operating means, and when the operating speed is below a certain threshold, the relationship between the operating speed and the driving speed is linear, and when the operating speed is above a certain threshold Discloses a non-linear optical apparatus.

JP 2009-151081 A JP 2013-178434 A

  However, the configurations of Patent Document 1 and Patent Document 2 cannot completely eliminate the decrease in controllability due to the large frictional resistance derived from the structure of the ultrasonic motor. In particular, when manual focus is performed using an electrical operation unit such as that disclosed in Patent Document 2, focus drive is continuously commanded according to the manual focus operation amount and the operation speed for each clock of the control unit. Then, intermittent driving by an ultrasonic motor is performed. At this time, sound may be generated by acceleration / deceleration depending on intermittent driving.

  SUMMARY An advantage of some aspects of the invention is that it provides a control device, a lens barrel, and an imaging device capable of suppressing sound generated during a manual focus operation using an ultrasonic motor.

  A control device according to one aspect of the present invention is a control device including an acquisition unit that acquires a signal related to lens driving from an operation unit, and a control unit that controls the lens based on the signal. Is based on the first driving speed of the lens calculated based on the target driving amount of the lens calculated based on the difference between the current position of the lens and the target position, and the acquisition period of the target driving amount. A slower second driving speed is set, and the lens is controlled to be driven at the second driving speed.

  A lens barrel according to another aspect of the present invention includes a lens, an operation unit that can be operated by a user, and the control device.

  An imaging apparatus as another aspect of the present invention includes an imaging element that photoelectrically converts an optical image formed via a lens, and the control apparatus.

  Other objects and features of the invention are described in the following embodiments.

  ADVANTAGE OF THE INVENTION According to this invention, the control apparatus, lens barrel, and imaging device which can suppress the sound which generate | occur | produces in the case of manual focus operation using an ultrasonic motor can be provided.

It is a flowchart which shows the control method in this embodiment. It is sectional drawing of the imaging device in this embodiment. It is a disassembled perspective view of the focus drive part and its related member in this embodiment. FIG. 6 is a relationship diagram between a target position and an actual position of a focus lens (focus group) determined by a manual focus operation unit as a comparative example. It is an enlarged view of the A section in FIG. It is an enlarged view of the B section in FIG. FIG. 5 is a schematic diagram illustrating a driving state of a focus group in FIG. 4. It is a schematic diagram which shows the drive state of the focus group in this embodiment. It is a block diagram of the control apparatus in this embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  First, with reference to FIG. 2 and FIG. 3, the imaging device (optical apparatus) in this embodiment is demonstrated. FIG. 2 is a cross-sectional view of the imaging apparatus 10. FIG. 3 is an exploded perspective view of the focus driving unit and its related members in the imaging apparatus 10. The imaging apparatus 10 of the present embodiment is a lens interchangeable digital single-lens reflex camera, and includes a camera body 200 (imaging apparatus body) and an interchangeable lens 100 (lens apparatus) that can be attached to and detached from the camera body 200. The However, the present embodiment is not limited to this, and can also be applied to an imaging device (camera) in which a camera body and a lens device are integrally formed.

  Reference numeral 101 denotes a mount (lens mount) of the interchangeable lens 100. The camera body 200 and the interchangeable lens 100 perform electrical communication with each other via the mount 101. Reference numeral 201 denotes an image sensor. The image sensor 201 includes a CCD sensor, a CMOS sensor, and the like, and converts a light amount (subject image, optical image) of a subject formed via the interchangeable lens 100 into an electric signal (performs subject image photoelectric conversion). ) A photoelectric conversion element.

  Next, the imaging optical system of the interchangeable lens 100 will be described. The interchangeable lens 100 of the present embodiment has a four-group imaging optical system including a first lens group L1, a second lens group L2, a third lens group L3, and a fourth lens group L4. The third lens group L3 includes lens groups L3A, L3B, L3C, L3D, and L3E. During the focus operation (focusing operation), the focus lens group (lens group L3B), which is a part of the third lens group L3, moves in the direction along the optical axis O (optical axis direction). During the zoom operation (magnification operation), all the lens groups move along each locus determined in the optical axis direction, and the main substrate 124 (control device) maintains the focus position changed by the zoom. The driving of the lens unit L3B is controlled so as to be Note that the lens group here is not a term indicating only a set of a plurality of lenses. The lens group may include only one lens. The lens group may be rephrased as a lens unit. Similar to the lens group, the lens unit may include a plurality of lenses or only one lens.

  The mount 101 of the interchangeable lens 100 is fixed to a fixed cylinder 102 with a screw (not shown) through an exterior ring 103. The exterior ring 103 is sandwiched and fixed between the mount 101 and the fixed cylinder 102. A zoom index (not shown) and operation switches are attached to the exterior ring 103. The guide tube 104 is fixed to the fixed tube 102 with a screw (not shown). The guide tube 104 is provided with a total of twelve four types of four straight grooves for guiding each lens group in the straight direction. On the outer periphery of the guide tube 104, a cam tube 105 (cam ring) is held rotatably around the optical axis. The cam cylinder 105 is provided with a total of twelve types of cam grooves (not shown) corresponding to the locus of each lens group during the zoom operation. A roller, which is a cam follower (not shown) that supports the straight groove, the cam groove, and the holding frame of each lens group, causes the cam cylinder 105 to rotate around the optical axis with a constant position in the optical axis direction during zoom operation, Each lens group can be moved straight along the optical axis along the trajectory.

  The lens holding frame 106 holds the first lens unit L1, and is fixed to the filter frame 107, which is linearly moved by a rectilinear groove, a cam groove, and a roller, with screws. The filter frame 107 is suspended in a rectilinear groove and a cam groove by a roller (not shown), and is linearly moved in the optical axis direction by zooming. Further, at the tip of the filter frame 107, a hood attachment portion is provided on the outer peripheral side, and a screw is provided on the inner periphery thereof, and accessories such as a filter can be attached. The second lens holding frame 108 holds the second lens unit L2, is suspended in a rectilinear groove and a cam groove by a roller (not shown), and is linearly moved in the optical axis direction by zooming.

  The lens holding frame 109 holds the lens group L3A among the lens groups L3A to L3E included in the third lens group L3, and is suspended in a straight groove and a cam groove by a roller (not shown). Move straight ahead. The lens holding frame 110 holds the lens group L3B, which is a focus group, and is guided straight by the two guide bars 114 held by the lens holding frames 109 and 112. The lens group L3B is driven in the optical axis direction by the ultrasonic motor unit 115 (focus driving unit) and a rack 116 that transmits the driving force of the ultrasonic motor unit 115 to the lens holding frame 110. The lens holding frame 111 holds the lens group L3C, and is held on the lens holding frame 109 using three rollers (not shown). The lens holding frame 111 holds an electromagnetic diaphragm unit 117 configured to include a diaphragm driving unit and a diaphragm blade unit. The lens holding frame 112 holds the lens group L3D and is fixed to the lens holding frame 109 with screws. The lens holding frame 113 holds the lens group L3E and constitutes a part of the shake correction unit 118. The shake correction unit 118 holds the lens holding frame 113 so as to be drivable in a direction orthogonal to the optical axis (direction orthogonal to the optical axis), and drives the lens holding frame 113 using a driving unit configured with a magnet and a coil. As a result, shake correction is performed.

  The moving cylinder 119 is suspended in a rectilinear groove and a cam groove by a roller (not shown) and is linearly moved in the optical axis direction by a zoom operation. The movable cylinder 119 holds the lens holding frame 120 that holds the fourth lens unit L4 via three adjustment rollers in the plane orthogonal to the optical axis and three adjustment rollers that adjust the tilt with respect to the optical axis O. ing. The lens holding frame 120 is held in a state where tilt adjustment and eccentricity adjustment with respect to the optical axis O can be performed.

  The zoom operation ring 121 can be zoomed by rotating the cam cylinder 105 by a zoom key (not shown) which is a connecting member with the cam cylinder 105 by rotating at a fixed position. The zoom operation ring 121 is provided with a cam groove (sensor cam) into which a movable pin of a resistance type linear sensor (potentiometer) (not shown) fixed to the fixed cylinder 102 is fitted. Therefore, the output of the linear sensor changes according to the rotation amount of the zoom operation ring 121, and the current zoom information can be detected.

  The focus operation ring 122 is a manual focus operation unit (MF operation unit, operation means), and is sandwiched between a fixed cylinder 102 and a decorative ring 123 described later so that it can rotate at a fixed position outside the fixed cylinder 102. In addition, the focus operation ring 122 is a combination of two photo interrupters provided on the fixed cylinder 102 and a comb-shaped light shielding portion provided on the inner diameter of the focus operation ring 122, so that the rotation amount and rotation of the focus operation ring 122 are increased. Detect speed and direction of rotation. More specifically, when the focus operation ring 122 rotates around the optical axis, the output voltage obtained by repeating the light transmission / light-shielding of the photo interrupter by the comb-like light-shielding part is electrically processed to obtain a pulse count. . The main board 124 (main circuit board, control device) rotates in the direction of rotation based on the amount and speed of the pulse count obtained every predetermined control cycle (main clock) and the phase difference between the signals of the two photo interrupters. And the focus group drive amount (target drive amount) is calculated.

  The decorative ring 123 prevents the focus operation ring 122 from coming off the fixed cylinder 102 and is fixed to the fixed cylinder 102 by three engaging claws. The main board 124 controls the entire interchangeable lens 100 (lens barrel) such as the ultrasonic motor unit 115, the electromagnetic drive diaphragm unit 117, and the shake correction unit 118, and is fixed to the fixed cylinder 102 with screws. Has been.

  The optical scale 125 is a strip-shaped reflective scale that constitutes an optical position detection encoder, and is attached to the lens holding frame 110 that holds the lens group L3B (focus group). The sensor head 126 constitutes an optical position detection encoder and is held by a sensor holder 127. The sensor head 126 needs to be positioned with high accuracy with respect to the optical scale 125, and is fixed in a relationship between the sensor holder 127 and the lens holding frame 110. In this embodiment, since the configuration of the optical position detection encoder and the detection principle thereof are known, the description thereof is omitted, but a sensor other than the optical sensor such as a magnetic sensor (MR sensor) may be used. Good. Further, the position of the lens holding frame 110 is a position in the optical axis direction, and a command signal for position control of the lens group L3B is generated according to this position.

  The sensor head 126 is connected to the main substrate 124 (control device) via a flexible printed wiring board 128 (FPC). The main board 124 performs focus control by PID control which is feedback control based on the focus position information obtained from the sensor head 126. In the present embodiment, the main substrate 124 as a control device that performs focus control is provided in the interchangeable lens 100, but the present invention is not limited to this, and a control device having such a function is provided in the camera body 200. It may be provided.

  Next, as a comparative example, the behavior of the focus group when a drive command is output using a manual focus operation unit (focus operation ring) by conventional control will be described with reference to FIGS. FIG. 4 is a relationship diagram between the target position and actual position of the focus lens (focus group) determined by the manual focus operation unit. In FIG. 4, the horizontal axis indicates time, and the vertical axis indicates the driving amount of the focus group. A part in FIG. 4 shows a state in which the focus operation ring is slowly rotated, and a part B shows a state in which the focus operation ring is rotated fast. 5 is an enlarged view of portion A in FIG. 4, and FIG. 6 is an enlarged view of portion B in FIG. FIG. 7 is a schematic diagram illustrating a driving state of the focus lens. 5 to 7, the target position is indicated by a broken line, and the actual position is indicated by a solid line. Here, the switching cycle of the target position coincides with 120 Hz (about 8.3 ms) which is the clock (main clock) of the main board 124.

  As shown in FIG. 5, when the manual focus operation unit (focus operation ring) rotates slowly, the target position does not change every 120 Hz, and the actual movement pulse is delayed by several ms after the target position changes. Changes. On the other hand, as shown in FIG. 6, when the focus operation ring rotates rapidly, the target position (the amount of the target pulse) changes for each main clock, and the movement locus represented by the actual movement pulse is 120 Hz which is the main clock. Similar to a sine wave of the same frequency.

  As shown in FIG. 7, a sine wave is generated when the target position is switched, because “target position−actual position” is large, and the focus group is accelerated by PID control. This is because “target position−actual position” becomes small and deceleration is applied. When the focus group moves as shown in the B part (FIG. 6) as described above, there is acceleration and deceleration of a frequency related to 120 Hz which is a control cycle (main clock frequency). As a result, noise is generated by the force for causing such acceleration and deceleration. For example, in the control as described above, since acceleration and deceleration are repeated every 120 Hz, noise of 240 Hz is mainly generated.

  Next, focus group control by the main board 124 (control device) in the present embodiment will be described with reference to FIG. FIG. 8 is a schematic diagram showing a driving state of the focus group in the present embodiment. In the present embodiment, the first drive speed is defined as the following formula (1).

First drive speed = (target position−actual position) / focus group drive amount acquisition cycle (1)
Further, a speed that is slower than the first drive speed and is obtained by multiplying the first drive speed by a coefficient (1/3 in the present embodiment) is set as the second drive speed, and the maximum drive speed of the focus group is controlled as the second drive speed. .

  The wavy line in FIG. 8 indicates the target position of the focus group, and the solid line indicates the actual position (current position). A one-dot chain line in FIG. 8 is a locus assuming a case where the focus group moves at the first drive speed. By setting the second drive speed, the target position is not reached even after 8.3 ms has elapsed, and therefore deceleration (deceleration period) does not occur. Further, since the speed does not become low, acceleration (acceleration period) does not occur. As a result, the speed change can be reduced and the generation of noise can be suppressed.

  In addition, when the first drive speed determined according to the MF operation speed is below a certain level, by setting a third drive speed that makes the second drive speed and the first drive speed the same, Control is performed as instructed by the MF operation unit. By performing the above-described control, it becomes insufficient after 8.3 ms, which is the main clock. For this reason, it is possible to suppress deceleration and acceleration generated for each main clock, and to smoothly move the focus group, and it is possible to suppress sound generated depending on the main clock. Further, by setting the third drive speed, when the MF operation by the user becomes gentle, it is possible to perform the same control as in the conventional case in which the user can stop at the position as intended. In the present embodiment, 1/3 of the first drive speed is set as the second drive speed, but the present invention is not limited to this. If it is slower than the first drive speed, the second drive speed may be arbitrarily set according to the product form. Moreover, it is possible to exhibit an effect more efficiently by changing the second drive speed stepwise or continuously for each first drive speed.

  Next, with reference to FIGS. 1 and 9, the focus group control device and control method in the present embodiment will be described. FIG. 1 is a flowchart showing a control method in the present embodiment. FIG. 9 is a block diagram of the main board 124 (control device) in the present embodiment. Each step in FIG. 1 is mainly executed by each part of the main board 124 (control device).

  As shown in FIG. 9, the main board 124 includes an acquisition unit 124a and a control unit 124b. The acquisition unit 124a acquires a signal related to driving of the focus group (lens) from the focus operation ring 122 (operation unit). The control unit 124b controls the lens based on the signal acquired by the acquisition unit 124b.

  First, in step S <b> 1 of FIG. 1, when the power of the camera body 200 is turned on by the user, supply of power to the interchangeable lens 100 is started. Then, communication between the camera body 200 (camera CPU) and the interchangeable lens 100 (lens CPU provided on the main board 124 as a control device) starts. Through this communication, the mounted interchangeable lens 100 and the camera body 200 recognize each other, and the interchangeable lens 100 and the camera body 200 each capture necessary information.

  Subsequently, in step S2, the control device determines whether or not it is in a shooting preparation state. If it is not in the shooting preparation state, step S2 is repeated. On the other hand, if it is in the shooting preparation state, the process proceeds to step S3. In step S3, the control device determines whether or not an MF operation has been performed by the user, that is, whether or not the manual focus operation unit (focus operation ring 122) has been operated. If the MF operation is not performed, the process returns to step S2. On the other hand, when the MF operation is performed, the control device detects the operation amount and the operation speed of the MF operation, and proceeds to step S4. In step S4, the control device calculates the first drive speed of the focus group based on the operation amount and operation speed of the MF operation detected in step S3.

  Subsequently, in step S5, the control device compares the first drive speed calculated in step S4 with a preset third drive speed. When the first drive speed is lower than the third drive speed, the process proceeds to step S8. On the other hand, when the first drive speed is higher than the third drive speed, the process proceeds to step S6. In step S6, the control device calculates a second drive speed. Subsequently, in step S7, the control device replaces the first drive speed with the second drive speed.

  Subsequently, in step S8, the control device determines whether or not the first drive speed is higher than the maximum motor speed determined according to the performance of the motor. When the first drive speed is smaller than the maximum motor speed, the process proceeds to step S10. On the other hand, if the first drive speed is greater than the maximum motor speed, the process proceeds to step S9. In step S9, the control device replaces the first drive speed with the motor maximum speed. At this time, the same applies to the case where the first drive speed is replaced with the second drive speed in step S7. In this case, the second drive speed is substantially compared with the maximum motor speed. become.

  Subsequently, in step S10, the control device drives the focus group (focus lens) based on the determined first drive speed. Subsequently, in step S11, the control device determines whether or not the S1 button has been pressed (whether or not the release button is half pressed). When the S1 button is pressed, the process proceeds to the shooting sequence in step S12.

  As described above, in the present embodiment, the control unit 124b is based on the target drive amount of the lens calculated based on the difference between the current position of the lens and the target position (actual position), and the target drive amount acquisition cycle. The second driving speed that is slower than the first driving speed of the lens calculated in the above is set. Then, the control unit 124b controls to drive the lens at the second driving speed. In other words, the control means 124b is a second smaller than the first target drive amount of the lens calculated based on the difference between the current position of the lens and the target position every predetermined period (target drive amount acquisition cycle). A target drive amount is set, and control is performed to drive the lens using the second target drive amount. That is, since the second target drive amount is used, the target position is not reached even after a predetermined period has elapsed. Alternatively, the control unit 124b calculates a target driving amount of the lens based on a difference between the current position of the lens and the target position for each predetermined period, and the predetermined period includes at least one of the acceleration period and the deceleration period of the lens. It can also be excluded.

  Preferably, the first drive speed is calculated by dividing the target drive amount by the acquisition cycle for each target drive amount acquisition cycle. Preferably, the second drive speed is calculated by multiplying the first drive speed by a predetermined coefficient (for example, 1/3) for each target drive amount acquisition period. Preferably, the second drive speed includes only one of a lens acceleration period or a deceleration period and a constant speed period for each target drive amount acquisition cycle. Preferably, the target drive amount acquisition cycle is the reciprocal of the clock frequency (main clock frequency) of the control means 124b.

  Preferably, the control unit 124b controls to drive the lens based on the rotation speed and the rotation amount of the operation unit (focus operation ring 122), and changes the second drive speed according to the rotation speed of the operation unit. . More preferably, the control unit 124b drives the lens at the second drive speed when the rotation speed of the operation unit is lower than a predetermined speed. On the other hand, when the rotational speed is higher than the predetermined speed, the control unit 124b drives the lens at a predetermined driving speed (motor maximum speed) without using the second driving speed.

  According to the present embodiment, a control device, a lens barrel, and an imaging device capable of suppressing sound generated according to a clock frequency (main clock frequency) during a manual focus operation using an ultrasonic motor. Can be provided.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

  For example, although the present embodiment has been described with respect to driving of the focus lens, the present invention is not limited to this, and can be applied to driving of other lenses such as a zoom lens and an anti-vibration lens (correction lens). Although this embodiment has been described with respect to an interchangeable lens used in a single-lens reflex film camera, it can also be applied to lens barrels of various photographing devices (optical devices) such as a lens shutter camera, a digital camera, and a video camera.

124 Main board (control device)
124a acquisition means 124b control means

Claims (12)

Obtaining means for obtaining a signal relating to driving of the lens from the operating means;
A control means for controlling the lens based on the signal,
The control means includes
Slower than the first driving speed of the lens calculated based on the target driving amount of the lens calculated based on the difference between the current position of the lens and the target position, and the acquisition cycle of the target driving amount. Set the second drive speed,
Controlling to drive the lens at the second drive speed;
A control device characterized by that. The first drive speed is calculated by dividing the target drive amount by the acquisition cycle for each acquisition cycle of the target drive amount.
The control device according to claim 1. The second drive speed is calculated by multiplying the first drive speed by a predetermined coefficient for each acquisition period of the target drive amount.
The control device according to claim 1, wherein the control device is a control device. The second drive speed includes only one of an acceleration period or a deceleration period of the lens and a constant speed period for each acquisition period of the target drive amount.
The control device according to claim 1, wherein the control device is a control device. The control means controls to drive the lens based on the rotation speed and rotation amount of the operation means,
Changing the second drive speed according to the rotational speed of the operating means;
The control device according to claim 1, wherein the control device is a control device. The control means includes
When the rotation speed of the operation means is slower than a predetermined speed, the lens is driven at the second drive speed,
When the rotational speed is faster than the predetermined speed, the lens is driven at a predetermined driving speed without using the second driving speed.
The control device according to claim 5. The acquisition period of the target drive amount is the reciprocal of the clock frequency of the control means.
The control device according to claim 1, wherein the control device is a control device. Obtaining means for obtaining a signal relating to driving of the lens from the operating means;
A control means for controlling the lens based on the signal,
The control means has a predetermined period,
Setting a second target drive amount smaller than the first target drive amount of the lens calculated based on the difference between the current position of the lens and the target position;
Control to drive the lens using the second target drive amount;
A control device characterized by that. Obtaining means for obtaining a signal relating to driving of the lens from the operating means;
A control means for controlling the lens based on the signal,
The control means calculates a target driving amount of the lens based on a difference between a current position of the lens and a target position for each predetermined period;
The predetermined period does not include at least one of an acceleration period and a deceleration period of the lens;
A control device characterized by that. A lens,
Operation means that can be operated by the user;
A lens barrel comprising: the control device according to claim 1. The lens is a focus lens;
The operation means is a manual focus operation unit.
The lens barrel according to claim 10. An image sensor that photoelectrically converts an optical image formed through a lens;
An imaging device comprising: the control device according to claim 1.