JPWO2019172453A1 - Lens barrel and imaging device - Google Patents

Abstract

The lens barrel is specified based on a focus lens that adjusts the focal position of the optical system, a drive unit that drives the focus lens to move in the optical axis direction, and a target position for moving the focus lens by the drive unit. It has a drive control unit that drives and controls the drive unit based on the position and the current position of the focus lens.

Description

Capture by reference

This application claims the priority of Japanese Patent Application No. 2018-014446, which is a Japanese application filed on March 8, 2018, and incorporates it into this application by referring to its contents.

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

There is an automatic focus adjusting device that automatically adjusts the focus using the defocus amount (see, for example, Patent Document 1 below). However, when the target position is set according to the amount of defocus and the position of the image plane of the subject, the motor that drives the focus lens is frequently stopped, and the movement of the focus lens tends to be intermittent.

Japanese Unexamined Patent Publication No. 1-107224

The lens barrel, which is one aspect of the invention disclosed in the present application, includes a focus lens for adjusting the focal position of an optical system, a drive unit for driving the focus lens to move in the optical axis direction, and the drive unit. It has a specific position based on a target position for moving the focus lens, and a drive control unit that drives and controls the drive unit based on the current position of the focus lens.

The lens barrel, which is another aspect of the invention disclosed in the present application, includes a focus lens for adjusting the focal position of an optical system, a drive unit for moving the focus lens in the optical axis direction, and the focus lens by the drive unit. It has a second position based on a first position for moving the lens, and a drive control unit that drives and controls the drive unit based on the position of the focus lens.

The lens barrel, which is another aspect of the invention disclosed in the present application, includes a focus lens for adjusting the focal position of the optical system, a driving unit for moving the focus lens in the optical axis direction, and a first position of the focus lens. The driving unit is moved based on the third position based on the second position, which is the second position to be moved from, and is different depending on the time, and the position of the focus lens when the focus lens is being moved. It has a drive control unit for drive control.

The imaging device, which is one aspect of the invention disclosed in the present application, includes a focus lens that adjusts the focal position of an optical system, a drive unit that drives the focus lens so as to move in the optical axis direction, and the drive unit. It has a specific position based on a target position for moving the focus lens, and a drive control unit that drives and controls the drive unit based on the current position of the focus lens.

FIG. 1 is an explanatory diagram showing an example of imaging a subject. FIG. 2 is an explanatory diagram showing a hardware configuration example of the image pickup apparatus. FIG. 3 is a graph showing an example of motor drive control. FIG. 4 is a block diagram showing a functional configuration example of the image pickup apparatus. FIG. 5 is a flowchart showing an example of a processing procedure of the camera-side processor. FIG. 6 is a flowchart showing an example of a response processing procedure of the lens-side processor. FIG. 7 is a flowchart showing a focusing processing procedure example 1 of the lens-side processor. FIG. 8 is a flowchart showing an example of a processing procedure of the image pickup apparatus according to the selective shooting mode. FIG. 9 is a flowchart showing a focusing processing procedure example 2 of the lens-side processor.

<Subject imaging example>
FIG. 1 is an explanatory diagram showing an example of imaging a subject. This embodiment is an example of taking an image while tracking the subject 110 approaching the image pickup apparatus 100. In FIG. 1, an automobile, which is an example of the subject 110, approaches the image pickup apparatus 100 from a point at a subject distance R at a speed V. Although the subject 110 approaches the image pickup apparatus 100 in FIG. 1, the subject 110 may be separated from the image pickup apparatus 100. The image pickup apparatus 100 is, for example, an interchangeable lens type digital camera in which a camera body 101 and a lens barrel 102 are communicably connected.

In this embodiment, an interchangeable lens type digital camera will be described as an example, but the image pickup apparatus 100 may be a digital camera in which the camera body 101 and the lens barrel 102 are integrated. Further, the image pickup apparatus 100 can not only shoot a still image but also shoot a moving image. The image pickup device 100 may be a digital video camera, a smartphone, a tablet, a game machine, or a surveillance camera in addition to the digital camera. Further, the image pickup device 100 may be mounted on a moving body such as an automobile, a bicycle, or a drone.

<Hardware configuration example of imaging device 100>
FIG. 2 is an explanatory diagram showing a hardware configuration example of the image pickup apparatus 100. The camera body 101 includes an input device 210, a mirror unit 211, a pentaprism 212, an eyepiece unit 213, an image sensor 214, an analog front-end circuit (AFE) 215, an LSI (Large Scale Integration) 216, and the like. It has an AF (Auto Focus) sensor 217, a body-side processor 218, and a body-side storage device 219.

The input device 210 is, for example, a device that accepts input from a release button 210a, a dial 210b, a microphone 210c (or another button or a touch panel). When the release button 210a is pressed halfway, the body-side processor 218 starts autofocus, and when the release button 210a is fully pressed, the body-side processor 218 releases the shutter to take an image of the subject 110.

The dial 210b can be switched between a still image shooting mode and a moving image shooting mode, for example. The body-side processor 218 images the subject 110 in a mode switched by the dial 210b. The microphone 210c receives, for example, an external voice input in motion shooting.

The mirror unit 211 has a quick return mirror 211a and a sub mirror 211b. The quick return mirror 211a guides the subject light from the lens barrel 102 to the pentaprism 212. When the release button 210a is fully pressed, the quick return mirror 211a jumps up according to an instruction from the body-side processor 218, whereby the image sensor 214 can receive the subject light.

The sub-mirror 211b guides the subject light from the lens barrel 102 to the AF sensor 217. The pentaprism 212 guides the subject light reflected by the quick return mirror 211a to the eyepiece 213. The eyepiece 213 is a member that the operator's eyes come into contact with, and makes it possible to observe the subject 110 by the subject light from the pentaprism 212.

The image sensor 214 receives the subject light in a state where the quick return mirror 211a is flipped up and converts it into an analog electric signal. The image sensor 214 receives the subject light from the optical system 220 and converts it into an electric signal. The image sensor 214 may be, for example, an XY address type solid-state image sensor (for example, CMOS (Complementary Metal-Oxide Semiconductor)) or a sequential scanning type solid-state image sensor (for example, CCD (Charge Coupled Device)). There may be.

The analog front-end circuit 215 performs signal processing on the analog electric signal from the image sensor 214. The analog front-end circuit 215 sequentially executes electric signal gain adjustment, analog signal processing (correlation double sampling, black level correction, etc.), A / D conversion processing, and digital signal processing (defect pixel correction, etc.) to obtain a RAW image. Data is generated and output to LSI 216.

The LSI 216 specifies specific image processing such as color interpolation, white balance adjustment, contour enhancement, gamma correction, and gradation conversion, coding processing, decoding processing, compression / decompression processing, and the like for RAW image data from the analog front-end circuit 215. It is an integrated circuit that executes processing. Specifically, the LSI 216 may be realized by a PLD (Programmable Logic Device) such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field-Programmable Gate Array).

The AF sensor 217 receives the subject light reflected by the sub mirror 211b and detects the amount of deviation of the subject 110 from the in-focus position. This amount of deviation corresponds to the amount of defocus D, which is the distance between the image sensor 214 and the image plane IS of the subject image separated from the image sensor 214 in the direction of the optical axis OA. Although the AF sensor 217 is a phase difference detection AF sensor in this example, it may be a contrast AF sensor that detects the in-focus position and the amount of deviation based on the contrast difference of the subject image, and the subject light reflected by the sub mirror 211b. An image plane phase difference AF sensor in which a light receiving element that receives light is embedded in the image pickup element 214 may be used.

The body-side processor 218 controls the camera body 101. Specifically, for example, the body-side processor 218 stores the image data from the LSI 216 in the body-side storage device 219. Further, the body-side processor 218 executes still image shooting or moving image shooting according to the mode selected by the dial 210b. Further, the body-side processor 218 detects a half-press of the release button 210a, instructs the autofocus operation by the AF sensor 217, and acquires the amount of deviation from the focusing position from the AF sensor 217.

In addition, the body-side processor 218 calculates the image plane velocity of the subject image. Specifically, for example, the body-side processor 218 calculates the time change of the amount of deviation from the AF sensor 217 per unit time as the image plane velocity. Further, the defocus amount D, which is the difference between the position where the subject 110 is imaged (for example, the position of the image plane IS) and the position of the image sensor 214, is the offset amount.

The body-side processor 218 transmits the calculated image plane velocity and offset amount to the lens-side processor 221. The body-side processor 218 may calculate the target position by adding the offset amount to the actually measured position of the focus lens 220a instead of the offset amount, and transmit it to the lens-side processor.

The body-side processor 218 calculates, for example, an offset amount for each unit time, and determines whether or not the offset amount is within a predetermined tracking error range. If it is within the tracking error range, the body-side processor 218 indicates that the subject 110 is being tracked, and if it is outside the tracking error range, it indicates that the subject 110 is out of tracking.

The case where the subject 110 is out of tracking may be, for example, a case where the moving speed V of the subject 110 suddenly changes, or a case where the subject 110 is in focus. When the offset amount is out of the tracking error range, the body-side processor 218 transmits the image plane speed and the offset amount (or the target position) at the time when the offset amount is out of the tracking error range to the lens-side processor 221.

The body-side storage device 219 serves as a work area for the body-side processor 218. Further, the body-side storage device 219 is a non-temporary or temporary recording medium for storing various programs and data (for example, image data from LSI 216). Examples of the body-side storage device 219 include a ROM (Read Only Memory), a RAM (Random Access Memory), an HDD (Hard Disk Drive), and a flash memory. A plurality of body-side storage devices 219 may be mounted on the camera body 101, and at least one of them may be detachable from the camera body 101.

The lens barrel 102 includes an optical system 220 including a focus lens 220a, a lens-side processor 221, a lens-side storage device 222, a drive circuit 223, a motor 224, and an encoder 225. The optical system 220 is a group of n lenses in the m group (where m and n are integers of 1 or more) arranged in the direction of the optical axis OA, and the focus lens 220a is a lens thereof. Of the directions of the optical axis OA, the direction from the closest side to the infinity side is the optical axis + OA direction, and the direction from the infinity side to the nearest side is the optical axis −OA direction.

The focus lens 220a is a lens that can move in the direction of the optical axis OA and adjusts the focal position of the optical system 220. The current position of the focus lens 220a is, for example, the position of the principal point H when the reference position PO is used as a reference.

The lens-side processor 221 controls the lens barrel 102. Specifically, for example, the lens-side processor 221 receives various data from the body-side processor 218 and controls the drive circuit 223. The lens-side storage device 222 serves as a work area for the lens-side processor 221.

Further, the lens-side storage device 222 is a non-temporary or temporary recording medium for storing various programs and data (for example, data from the body-side processor 218). Examples of the lens-side storage device 222 include a ROM, RAM, HDD, and flash memory. A plurality of lens-side storage devices 222 may be mounted on the camera body 101, and at least one of them may be detachable from the camera body 101.

The drive circuit 223 generates a drive signal corresponding to the movement amount and the movement direction of the focus lens 220a under the control of the lens-side processor 221 and outputs the drive signal to the motor 224. The motor 224 is driven by a drive signal from the drive circuit 223 to move the focus lens 220a in the direction of the optical axis OA. As the motor 224, for example, an ultrasonic motor or a stepping motor is used.

The encoder 225 is composed of, for example, an optical encoder or a magnetic encoder, and transmits an electric signal indicating a movement amount and a movement direction detected by the movement of the focus lens 220a to the lens side processor 221. For example, when the motor 224 is an ultrasonic motor, the encoder 225 detects the position and speed of the cam ring driven by the rotation of the annular rotor and transmits the electric signal to the lens-side processor 221. When the cam ring is rotationally driven, the AF ring (not shown) holding the focus lens 220a moves in the direction of the optical axis OA.

<Example of drive control of motor 224>
FIG. 3 is a graph showing an example of drive control of the motor 224. (A) is a graph showing the temporal change of the target position and the current position of the focus lens 220a. The horizontal axis indicates time and the vertical axis indicates the position of the focus lens 220a. The solid line shows the time change of the target position of the focus lens 220a, and the alternate long and short dash line shows the time change of the measured position of the focus lens 220a.

“At the time of receiving the first drive instruction command” is when the drive instruction command including the offset amount (or the target position) and the image plane speed is received while the motor 224 is stopped. “At the time of overlap reception” is when a drive instruction command is received while the motor 224 is being driven.

(B) is a graph showing the time change of the drive speed of the motor 224. The horizontal axis represents time and the vertical axis represents the driving speed of the motor 224. (C) is a graph showing the temporal change of the ON / OFF state of the power supply of the motor 224. The horizontal axis represents time and the vertical axis represents the ON / OFF state of the power supply of the motor 224.

(0) When the body side processor 218 receives the first drive instruction command, for example, when the subject tracking is started by half-pressing the release button 210a, the measured position of the focus lens 220a at that time is acquired from the lens side processor 221 and the image plane. The speed v0 and the offset amount OF0 (or the target position) are calculated.

Then, the body-side processor 218 transmits a drive instruction command including the calculated information to the lens-side processor 221. When the lens-side processor 221 receives the drive instruction command at time t0, it outputs an instruction to turn on the power of the motor 224 to the drive circuit 223.

The drive circuit 223 turns on the power of the motor 224 according to the instruction. The motor 224 starts driving after a predetermined time dt has elapsed after the power is turned on. This predetermined time dt is a delay time indicating a start-up delay. The delay time dt is, for example, the time from the frequency at which the motor 224 does not rotate to the frequency at which the motor 224 starts to rotate when the motor 224 is an ultrasonic motor.

The delay time dt may be a time determined by the type of the focus lens 220a based on the characteristics of the focus lens 220a (for example, the inertia due to the weight and the inertia due to the movement in the direction of the optical axis OA). As a result, the delay time dt is set according to the characteristics of the focus lens 220a, and it is possible to determine the continuation of driving for each focus lens 220a.

The drive circuit 223 accelerates the drive speed of the motor 224 after the delay time dt elapses, and drives the motor 224 so that the measured position of the focus lens 220a becomes the target position according to the instruction from the lens-side processor 221. When the drive of the motor 224 is started, the focus lens 220a moves in the optical axis OA + direction and approaches the target position.

(1) Overlap reception 1
At time t1, the lens-side processor 221 receives the drive instruction command (image plane speed v1, offset amount OF1) from the body-side processor 218 in an overlapping manner. The lens-side processor 221 calculates the target position at time t1 by adding the actually measured position of the focus lens 220a at time t1 and the offset amount OF1. When the drive instruction command from the body-side processor 218 includes the target position, it is not necessary to calculate the target position.

The lens-side processor 221 determines whether to continue or stop driving the motor 224 at time t1. In this case, the lens-side processor 221 calculates the determination threshold value. The determination threshold value is a value obtained by adding a correction amount to the target position. The correction amount is the distance obtained by multiplying the image plane velocity and the delay time. Therefore, the position indicated by the determination threshold value (hereinafter referred to as the specific position) is a position on the infinity side of the target position.

The correction amount in this case is the distance obtained by multiplying the image plane velocity v1 at the time t1 and the delay time dt. This distance is a distance at which the target position catches up with the stopped position of the focus lens 220a when the drive of the motor 224 is stopped and restarted if the focus lens 220a is overtaking the target position. Therefore, by adding the distance to the target position in advance to obtain the determination threshold value, it is possible to suppress unnecessary stoppage of the motor 224.

In the overlap reception 1, at time t1, the determination threshold value is larger than the value of the position of the focus lens 220a, that is, the specific position indicated by the determination threshold value is located on the infinity side of the position of the focus lens 220a. The side processor 221 determines that the driving of the motor 224 should be continued, controls the driving of the motor 224, and moves the focus lens 220a so as to be in focus.

(2) Overlap reception 2
At time t2, the lens-side processor 221 receives the drive instruction command (image plane speed v2, offset amount OF2) from the body-side processor 218 in an overlapping manner. The lens-side processor 221 calculates the target position at time t2 by adding the actually measured position of the focus lens 220a at time t2 and the offset amount OF2. When the drive instruction command from the body-side processor 218 includes the target position, it is not necessary to calculate the target position.

The lens-side processor 221 determines whether to continue or stop driving the motor 224 at time t2. In this case, the lens-side processor 221 calculates a determination threshold value obtained by adding a correction amount to the target position at time t2. The correction amount in this case is the distance obtained by multiplying the image plane velocity v2 at the time t2 and the delay time dt.

In the overlap reception 2, at time t2, the determination threshold value is equal to or less than the value of the position of the focus lens 220a, that is, the specific position indicated by the determination threshold value is located closer to the position of the focus lens 220a. The side processor 221 determines that the drive of the motor 224 should be stopped, turns off the power of the motor 224, and stops the movement of the focus lens 220a. By this stop control, the motor 224 decelerates, and the drive speed becomes 0 after the deceleration time dct elapses.

(2a) Autonomous determination While the motor 224 is stopped, the lens-side processor 221 attempts an autonomous determination. The autonomous determination is a determination process for detecting the restart timing of the motor 224. Specifically, for example, the lens-side processor 221 determines whether or not the determination threshold value is larger than the actually measured position of the focus lens 220a for each unit time during the period when the motor 224 is stopped. Since the motor 224 is stopped, the actual measurement position of the focus lens 220a during the stop period of the motor 224 is constant.

The lens-side processor 221 calculates the offset amount for each unit time to specify the target position, calculates the correction amount obtained by multiplying the image plane speed v2 by the delay time dt, and adds it to the target position to calculate the determination threshold value. .. While the motor 224 is stopped, the body-side processor 218 may transmit the offset amount to the lens-side processor 221 every unit time, and the lens-side processor 221 uses the image plane speed v2 every unit time to target. The position may be updated, and the offset amount may be calculated from the difference between the updated target position and the actually measured position of the stopped focus lens 220a.

The lens-side processor 221 attempts autonomous determination until the specific position indicated by the determination threshold value exceeds the actually measured position of the focus lens 220a. When the specific position indicated by the determination threshold value at time t2a exceeds the actually measured position of the focus lens 220a, the drive circuit 223 is instructed to restart the motor 224.

The drive circuit 223 turns on the power of the motor 224 at time t2a according to the instruction. The motor 224 starts driving after the delay time dt has elapsed after the power is turned on at time t2a. When the drive of the motor 224 is started, the focus lens 220a is moved in the optical axis OA + direction and reapproaches the target position.

By instructing the restart of the motor 224 using the determination threshold value, it is possible to instruct the start of driving of the motor 224 earlier than in the case of comparing the target position without adding the correction amount with the actually measured position of the focus lens 220a. it can. Therefore, the time required to start tracking the subject 110 can be shortened, and the subject tracking performance can be improved.

The delay time dt is stored in the lens-side storage device 222 in advance, and the lens-side processor 221 reads it out from the lens-side storage device 222 when calculating the correction amount. Further, the lens-side processor 221 measures the immediately preceding delay time dt and stores it in the lens-side storage device 222, and when calculating the correction amount, reads out the immediately preceding delay time dt from the lens-side storage device 222 to obtain the correction amount. It may be used for calculation.

By using the actual delay time dt, the timing of restarting the motor 224, that is, the time until the tracking of the subject 110 is started can be estimated more accurately, and the subject tracking performance can be improved. Further, in the autonomous determination while the motor 224 drive is stopped, the deceleration time dct at the time when the motor 224 is stopped immediately before may be taken into consideration.

By adding the deceleration time to the delay time and then multiplying the image plane speed to calculate the correction amount, the longer the deceleration time, the larger the determination threshold value. Therefore, the target position can be reached earlier to the stop position of the focus lens 220a. Further, the number of times of noise generated when the motor 224 is stopped and started is reduced, and the motor 224 can be driven quietly.

(3) Overlap reception 3
At time t3, the lens-side processor 221 receives the drive instruction command (image plane speed v3, offset amount OF3) from the body-side processor 218 in an overlapping manner. The lens-side processor 221 calculates the target position at time t3 by adding the actually measured position of the focus lens 220a at time t3 and the offset amount OF3. If the drive instruction command from the body-side processor 218 includes the target position, it is not necessary to calculate the target position.

The lens-side processor 221 determines whether to continue or stop driving the motor 224 at time t3. In this case, the lens-side processor 221 calculates a determination threshold value obtained by adding a correction amount to the target position at time t3. The correction amount in this case is the distance obtained by multiplying the image plane velocity v3 at the time t3 and the delay time dt.

In the overlap reception 3, at time t3, the determination threshold value is larger than the value of the position of the focus lens 220a, that is, the specific position indicated by the determination threshold value is located on the infinity side of the position of the focus lens 220a. The side processor 221 determines that the driving of the motor 224 should be continued, controls the driving of the motor 224, and moves the focus lens 220a so as to be in focus. In this example, since the position of the focus lens 220a is on the infinity side of the target area, it is preferable to drive and control the motor 224 to reduce the moving speed of the focus lens 220a.

<Example of functional configuration of imaging device 100>
FIG. 4 is a block diagram showing a functional configuration example of the image pickup apparatus 100. The camera body 101 has a camera control unit 410. Specifically, the camera control unit 410 is realized, for example, by causing the body-side processor 218 to execute a program stored in the body-side storage device 219 shown in FIG.

As described with reference to FIG. 2, the camera control unit 410 performs image processing on the RAW image data from the analog front-end circuit 215. Further, the camera control unit 410 uses the amount of deviation from the AF sensor 217, that is, the defocus amount D, the measured position of the focus lens 220a from the drive control unit 421, and the unit time to determine the image plane speed. calculate. The camera control unit 410 sets the defocus amount D as the offset amount, and transmits a drive instruction command including the offset amount and the image plane speed to the calculation unit 420.

Further, the camera control unit 410 receives an audio input from the microphone 210c when the moving image shooting mode is selected by the dial 210b. The camera control unit 410 transmits an adjustment command including information on the current selection mode (movie shooting mode) and the volume of the input voice (indicating that the volume is below the threshold value) to the detection unit 423.

The lens barrel 102 includes a calculation unit 420, a drive control unit 421, a drive unit 422, and a detection unit 423. The calculation unit 420, the drive control unit 421, the drive unit 422, and the detection unit 423 are configured as a drive device for driving the focus lens 220a.

The calculation unit 420 receives a drive instruction command (image plane speed, offset amount) from the camera control unit 410, and calculates the correction amount. The calculation unit 420 calculates the target position by adding the current actually measured position of the focus lens 220a and the offset amount. The calculation unit 420 calculates the determination threshold value by adding the target position and the correction amount. Specifically, the calculation unit 420 is realized by causing the lens-side processor 221 to execute the program stored in the lens-side storage device 222 shown in FIG. 2, for example.

The drive control unit 421 controls the drive of the motor 224 based on the determination threshold value and the current measured position of the focus lens 220a. When the determination threshold value is larger than the value of the current measured position of the focus lens 220a, the drive control unit 421 controls to continue driving the motor 224. When the determination threshold value is equal to or less than the value of the current measured position of the focus lens 220a, the drive control unit 421 controls to stop the drive of the motor 224.

The drive control unit 421 determines a drive control signal to be output to the drive unit 422 so that the position of the focus lens 220a is within the tracking error range, depending on the rotation speed and rotation speed of the motor 224 from the drive unit 422. Specifically, the drive control unit 421 is realized by causing the lens-side processor 221 to execute a program stored in the lens-side storage device 222 shown in FIG. 2, for example.

The drive unit 422 moves the focus lens 220a in the direction of the optical axis OA by the drive control signal from the drive control unit 421. Further, the drive unit 422 detects the rotation speed and the rotation direction of the motor 224 and returns the motor to the drive control unit 421. Specifically, the drive unit 422 is realized by, for example, the drive circuit 223, the motor 224, and the encoder 225 shown in FIG.

The detection unit 423 instructs the drive control unit 421 to give priority to drive continuation based on the adjustment command from the camera control unit 410. Specifically, for example, when an adjustment command is detected, the detection unit 423 instructs the calculation unit 420 and the drive control unit 421 to forcibly continue driving. In this case, the calculation unit 420 does not calculate the determination threshold value, the drive control unit 421 does not try to compare the determination threshold value with the actually measured position of the focus lens 220a, and determines that the drive is continued at the timing of the overlap reception. The drive unit 422 is driven and controlled.

When the motor 224 is stopped or started, a sound is suddenly generated from the motor 224, and such a sound may be picked up by the microphone 210c when shooting a moving image of a quiet scene. Therefore, by forcibly continuing the driving, it is possible to suppress the generation of the motor 224 sound when the motor 224 is stopped or started, and to shoot a high-quality moving image.

Further, the determination threshold value may be set to a larger value instead of forcibly continuing the drive. For example, when an adjustment command is detected, the detection unit 423 instructs the calculation unit 420 to give priority to drive continuation. The calculation unit 420 multiplies the correction amount (= image plane velocity × delay time) by a weight larger than 1.0 (for example, 1.5) to make the determination threshold larger than when the weight is not multiplied. As a result, the probability that the drive control unit 421 determines the drive continuation of the drive unit 422 increases, and the drive continuation can be prioritized.

Although the detection unit 423 has multiplied the weight by the correction amount, the weight may be multiplied by the target position or the determination threshold value. Specifically, the detection unit 423 is realized by causing the lens-side processor 221 to execute a program stored in the lens-side storage device 222 shown in FIG. 2, for example.

<Example of processing procedure of body side processor 218>
FIG. 5 is a flowchart showing an example of a processing procedure of the body-side processor 218. This flowchart is triggered by, for example, the start of AF by half-pressing the release button 210a. The body-side processor 218 transmits a request for acquiring the current position of the focus lens 220a to the lens-side processor 221 and acquires the current position of the focus lens 220a from the lens-side processor 221 (step S501).

The body-side processor 218 acquires the defocus amount D from the AF sensor 217 as an offset amount (step S502), and calculates the image plane velocity (step S503). Then, the body-side processor 218 transmits a drive instruction command including the image plane speed and the offset amount to the lens-side processor 221 (step S504).

Then, when the body-side processor 218 waits for the elapse of the unit time (step S505: No) and the unit time elapses (step S505: Yes), the body-side processor 218 receives the latest defocus amount D from the AF sensor 217. It is acquired as an offset amount (step S506), and it is determined whether or not the focus lens 220a follows the target position (step S507). Specifically, for example, the body-side processor 218 determines whether or not the offset amount acquired in step S506 is within the tracking error range.

When the offset amount is within the tracking error range, that is, when it is following (step S507: Yes), the process returns to step S505, and the body-side processor 218 waits for the next unit time elapse (step S505: No). When the offset amount is out of the tracking error range, that is, when it is not following (step S507: No), the body-side processor 218 returns to step S503, and the body-side processor 218 newly calculates the image plane velocity. It will be.

In step S505, when the unit time has not elapsed (step S505: No), the body-side processor 218 determines whether or not AF (Autofocus) has ended (step S508). Specifically, for example, the body-side processor 218 determines whether or not the release button 210a is fully pressed.

If AF is not completed (step S508: No), the process returns to step S505, and the body-side processor 218 waits for the passage of a unit time (step S505: No). When AF is completed (step S508: Yes), the body-side processor 218 ends a series of processes.

<Example of response processing procedure for lens-side processor 221>
FIG. 6 is a flowchart showing an example of a response processing procedure of the lens-side processor 221. When the lens-side processor 221 listens for a lens position acquisition request from the body-side processor 218 (step S601: No) and receives the lens position acquisition request (step S601: Yes), the lens-side processor 221 receives a detection signal from the encoder 225 to cause the focus lens 220a. The current measured position is acquired and transmitted to the body side processor 218 (step S602).

As a result, the body-side processor 218 can acquire the current actually measured position of the focus lens 220a (step S501), and the lens-side processor 221 drives and controls the motor 224 to start driving the motor 224. Therefore, the motor 224 is rotationally driven to move the focus lens 220a in the optical axis OA + direction so as to approach the target position over time.

<Example of focusing processing procedure for lens-side processor 221>
FIG. 7 is a flowchart showing a focusing processing procedure example 1 of the lens-side processor 221. The lens-side processor 221 waits for reception of a drive instruction command (overlap reception) while driving the motor 224 (step S701: No).

When the drive instruction command is received (step S701: Yes), the lens-side processor 221 determines whether or not the motor 224 is being stopped (step S702). The motor 224 receives, for example, a drive stop command (for example, a drive instruction command having an offset amount of 0) from the body side processor 218 when the motor 224 is stopped by starting the drive stop control in step S705 described later and when the subject 110 is stationary. If so, the drive is stopped.

When the drive is not stopped (step S702: No), the lens-side processor 221 calculates a determination threshold value (step S703), and whether or not the determination threshold value is larger than the value of the lens position (currently measured position of the focus lens 220a). That is, it is determined whether or not the specific position indicated by the determination threshold value is located on the infinity side of the lens position (step S704).

When the determination threshold value is larger than the value of the lens position (step S704: Yes), the specific position indicated by the determination threshold value is located on the infinity side of the lens position, so that the focus lens 220a catches up with the specific position indicated by the determination threshold value. Not. Therefore, the driving of the motor 224 is continued, and the process returns to step S701.

When the determination threshold is equal to or less than the value of the lens position (step S704: No), the specific position indicated by the determination threshold is located at the same position as the lens position or closer to the lens position, so that the focus lens 220a has the determination threshold. It means that it is overtaking the same position as the specific position shown or the specific position. Therefore, the lens-side processor 221 drives and controls the motor 224 to start driving and stopping the motor 224 (step S705). As a result, the motor 224 is stopped. Then, the process returns to step S701.

In step S702, when the motor 224 is stopped driving (step S702: Yes), the lens-side processor 221 waits for the elapse of a unit time (step S706: No). When the unit time has elapsed (step S706: Yes), the lens-side processor 221 calculates the determination threshold value (step S707) and determines whether the determination threshold value is larger than the value of the lens position, that is, the determination indicated by the determination threshold value. It is determined whether or not the position is located on the infinity side of the lens position (step S708).

When the determination threshold value is equal to or less than the value of the lens position (step S708: No), the process returns to step S706. That is, the lens-side processor 221 does not drive the motor 224, the focus lens 220a maintains the stopped state, and waits for the passage of a unit time (step S706: No).

On the other hand, when the determination threshold value is larger than the value of the lens position (step S708: Yes), that is, when the specific position indicated by the determination threshold value is located on the infinity side of the lens position, the lens side processor 221 of the motor 224 The drive control is started (step S709), and the process returns to step S701 ((2a) autonomous determination in FIG. 3). Then, the lens-side processor 221 waits for a drive instruction command (step S701). In this way, the lens-side processor 221 can drive and control the motor 224 that moves the focus lens 220a in the direction of the optical axis OA.

<Example of processing procedure according to the selected shooting mode>
FIG. 8 is a flowchart showing an example of a processing procedure of the image pickup apparatus 100 according to the selective shooting mode. The body-side processor 218 determines whether the shooting mode selected by the dial 210b is the still image shooting mode or the moving image shooting mode (step S801). In the case of the still image shooting mode (step S801: still image), the process proceeds to step S806.

In the case of the moving image shooting mode (step S801: moving image), the body-side processor 218 determines whether or not the volume of the input voice from the microphone 210c is equal to or less than the threshold value (step S802). If it is not equal to or less than the threshold value (step S802: No), the process proceeds to step S806.

On the other hand, when it is equal to or less than the threshold value (step S802: Yes), the body-side processor 218 transmits an adjustment command to the lens-side processor 221 (step S803), and proceeds to step S806. The adjustment command is, for example, an instruction that the lens-side processor 221 forcibly continues to drive the motor 224 without calculating the determination threshold value in the moving image shooting mode, or an instruction that increases the determination threshold value by using a weight. Is. Which instruction should be used can be set by user operation.

The lens-side processor 221 determines whether or not an adjustment command has been received from the body-side processor 218 (step S804). When the adjustment command is received (step S804: Yes), the lens-side processor 221 outputs the adjustment command to the detection unit 423 (step S805), and proceeds to step S806. On the other hand, if the adjustment command is not received (step S804: Yes), the process proceeds to step S806.

In the focusing process (step S806), the body-side processor 218 executes the process procedure shown in FIG. When the lens-side processor 221 receives the adjustment command, the lens-side processor 221 executes the focusing processing procedure 1 shown in FIG. 7. On the other hand, in the moving image shooting mode, when an adjustment command including an instruction to forcibly continue driving the motor 224 without calculating the determination threshold value is received, the lens side processor 221 performs the focusing process as shown in FIG. The drive of the motor 224 will be continued without execution.

The adjustment command in this case is an instruction to forcibly continue driving the motor 224 without calculating the determination threshold value in the moving image shooting mode, and the focusing processing procedure 1 shown in FIG. 7 is not executed. As a result, the driving of the motor 224 does not stop, so that it is possible to prevent the noise generated when the motor 224 is stopped or restarted.

In this way, when the volume of the input sound is low in the moving image shooting mode, the number of times the motor 224 is stopped or restarted can be suppressed, and the shot movie is suddenly stopped or restarted when the motor 224 is stopped or restarted. Suppress sound recording. Therefore, the image pickup apparatus 100 can shoot a high-quality moving image.

In FIG. 8, the motor 224 is continuously driven when the volume of the input sound is equal to or less than the threshold value in the moving image shooting mode, but the moving image shooting mode is selected regardless of the volume of the input sound. In that case, the motor 224 may be continuously driven. Further, in the moving image shooting mode, when an adjustment command including an instruction to increase the determination threshold value by using the weight is received, the processing procedure of FIG. 9 described later is executed.

FIG. 9 is a flowchart showing a focusing processing procedure example 2 of the lens-side processor 221. In the case of FIG. 9, instead of steps S703 and S707, the lens-side processor 221 calculates the determination threshold value by the calculation unit 420 using a weight of 1.0 or more as described above (steps S903 and S907).

As a result, the probability that the drive control unit 421 determines the drive continuation of the drive unit 422 increases, and the drive continuation can be prioritized. By prioritizing the continuation of driving, it is possible to suppress the number of stops and restarts of the motor 224 when the volume of the input sound is low in the moving image shooting mode, as in the case of forcibly continuing driving. It also suppresses sudden sound recording when the motor 224 is stopped or restarted.

Therefore, it is possible to shoot a high-quality moving image. Further, by not forcing the drive stop, if the determination threshold value is equal to or less than the value of the lens position, the drive of the motor 224 is stopped to suppress the overshoot of the focus lens 220a so that the subject 110 can be easily focused. can do.

In the above description of FIG. 3 and the like, an example in which the subject 100 moves from the near side to the infinity side has been described, but the subject 100 may move from the infinity side to the near side. The operation at this time will be described. It should be noted that detailed description of the same parts as those described above will be omitted.

When the body-side processor 218 starts tracking the subject 100 by, for example, half-pressing the release button 210a, the motor 224 starts driving and the focus lens 220a moves in the optical axis OA-direction (from the infinity side to the nearest side). And approach the target position. In the example below, "passing the target position" means that, for example, the focus lens 220a is located closer to the target position due to movement in the optical axis OA-direction.

When the lens-side processor 221 receives the drive instruction command (image plane speed v1, offset amount OF1) from the body-side processor 218 in an overlapping manner, the lens-side processor 221 determines whether to continue or stop the drive of the motor 224. In this case, the lens-side processor 221 calculates the determination threshold value. In this example, the position (specific position) indicated by the determination threshold value is the position closer to the target position.

If the determination threshold value is smaller than the value of the position of the focus lens 220a at the time of overlapping reception, that is, if the specific position is a position closer to the position of the focus lens 220a, the lens-side processor 221 uses the motor 224. The motor 224 is driven and controlled to move the focus lens 220a so that the focus lens 220a is in focus. At this time, when the position of the focus lens 220a is located closer to the target position, it is preferable to drive and control the motor 224 to reduce the moving speed of the focus lens 220a.

Further, if the determination threshold value is larger than the value of the position of the focus lens 220a at the time of overlapping reception, that is, if the specific position is at the position on the infinity side of the position of the focus lens 220a, the lens side processor 221 , It is determined that the drive of the motor 224 should be stopped, the power of the motor 224 is turned off, and the movement of the focus lens 220a is stopped. By this stop control, the motor 224 decelerates, and the drive speed becomes 0 after the deceleration time dct elapses.

If the specific position exceeds the actually measured position of the focus lens 220a while the motor 224 is stopped, the lens-side processor 221 instructs the drive circuit 223 to restart the motor 224. In this way, even when the subject 100 moves from the infinity side to the closest side, the driving continuation of the driving unit 422 can be prioritized over the driving stop.

(1) As described above, the lens barrel 102 described above is driven by a focus lens 220a that adjusts the focal position of the optical system 220, and a drive unit 422 that drives the focus lens 220a so as to move in the direction of the optical axis OA. A drive control unit 421 that drives and controls the drive unit 422 based on a specific position (determination threshold) based on a target position for moving the focus lens 220a by the unit 422 and a current position (lens position) of the focus lens 220a. Has. As a result, the continuation of driving of the driving unit 422 can be prioritized over the stopping of driving.

More specifically, when the current position of the focus lens 220a has exceeded the target position, the drive unit 422 is not necessarily stopped, and the drive may be continued. Therefore, the number of drive stops of the drive unit 422 can be suppressed, and smooth subject tracking can be performed.

(2) Further, in the above (1), the lens barrel 102 has and drives a calculation unit 420 that calculates a specific position based on a target position, an image plane speed of the subject 110, and a predetermined time. The control unit 421 drives and controls the drive unit 422 based on the specific position calculated by the calculation unit 420 and the current position of the focus lens 220a.

As a result, assuming that the lens position has exceeded the target position, the correction amount is added to the target position to set the specific position. Therefore, the subject can be tracked even during the period when the lens position catches up with the target position when the driving is stopped, and the tracking performance of the focus lens 220a can be improved.

(3) Further, in the above (2), the predetermined time is a time interval after the drive start instruction is given to the drive unit 422, for example, a delay time dt until the drive starts. As a result, the time from when the drive unit 422 is stopped to when it is restarted can be easily estimated, and when the drive is stopped, the period during which the lens position catches up with the target position is also predicted to track the subject. It can be carried out. Therefore, the tracking performance of the focus lens 220a can be improved.

(4) Further, in the above (3), the delay time dt may be a time determined based on the characteristics of the focus lens 220a. As a result, the specific position can be calculated according to the type of the focus lens 220a, and the tracking performance of the focus lens 220a can be improved.

(5) Further, in the above (2), the calculation unit 420 calculates a specific position when the target position and the image plane velocity are received from the camera body 101 communicably connected to the lens barrel 102. May be good. This eliminates the need for the lens barrel 102 to calculate the target position, and the calculation processing load on the lens barrel 102 can be reduced.

(6) Further, in the above (2), the calculation unit 420 is the difference between the position of the image sensor 214 and the position of the image plane IS of the subject 110 from the camera body 101 communicably connected to the lens barrel 102. When a certain offset amount (defocus amount D) and the image plane velocity are received, the target position may be calculated using the offset amount and the current position to calculate the specific position. As a result, it is not necessary to calculate the target position on the camera body 101, and the calculation processing load on the camera body 101 can be reduced.

(7) Further, in the above (1), even if the drive control unit 421 controls to continue driving the drive unit 422 when the specific position is located on the infinity side of the current position of the focus lens 220a. Good. As a result, the probability of continuing the driving of the driving unit 422 is increased as compared with the comparison between the target position and the lens position, and the number of driving stops can be suppressed. Therefore, smooth subject tracking can be performed.

(8) Further, in the above (1), even if the drive control unit 421 controls to stop the drive of the drive unit 422 when the specific position is not located on the infinity side of the current position of the focus lens 220a. Good. As a result, the movement of the focus lens 220a is stopped, and overshooting beyond the target position can be suppressed.

(9) Further, in the above (8), the drive control unit 421 drives the drive unit 422 when the specific position is located on the infinity side of the current position of the focus lens 220a while the drive unit 422 is stopped. May be controlled to start. As a result, the drive restart of the drive unit 422 can be set earlier, and the tracking performance of the focus lens 220a can be improved.

(10) Further, in the above (1), the drive control unit 421 may set the specific position to a position further away from the infinity side when the moving image shooting mode for shooting the moving image of the subject 110 is set. As a result, it is possible to forcibly select the drive control based on the moving image shooting rather than the continuous drive.

(11) Further, in the above (1), the drive control unit 421 sets the first specific position when the first volume is detected, and the second volume when a second volume smaller than the first volume is detected. It may be set to a position closer to the specific position. As a result, when the volume becomes lower than the first volume (for example, a predetermined threshold volume), the drive control based on the moving image shooting can be selected rather than the drive continuation.

(12) Further, in the above (1), the lens barrel 102 has a detection unit 423 that detects a specific event, and the drive control unit 421 is based on the specific event detected by the detection unit 423. The drive unit 422 may be driven and controlled. As a result, it is possible to forcibly select drive control based on a specific event rather than drive continuation.

(13) Further, in the above (11), the lens barrel 102 determines a specific position based on a target position, an image plane velocity of the subject 110, a predetermined time, and a coefficient (weight) related to a specific event. It has a calculation unit 420 to calculate, and the drive control unit 421 may drive and control the drive unit 422 based on the specific position calculated by the calculation unit 420 and the current position of the focus lens 220a. As a result, drive control based on a specific event can be prioritized over drive continuation.

(14) Further, in the above (13), the calculation unit 420 may calculate a specific position based on the volume from the outside. As a result, the drive control based on the external volume in a specific event can be prioritized over the drive continuation.

As described above, according to the present embodiment, smooth subject tracking can be performed.

100 imager, 101 camera body, 102 lens barrel, 110 subject, 218 body side processor, 220 focus lens, 221 lens side processor, 223 drive circuit, 224 motor, 225 encoder, 410 camera control unit, 420 calculation unit, 421 Drive control unit, 422 drive unit, 423 detector unit

The lens barrel, which is one aspect of the invention disclosed in the present application, includes a focus lens for adjusting the focal position of an optical system, a drive unit for driving the focus lens to move in the optical axis direction, and the drive unit. It has a specific position different from the target position for moving the focus lens, and a drive control unit that drives and controls the drive unit based on the current position of the focus lens.

The imaging device, which is one aspect of the invention disclosed in the present application, includes a focus lens that adjusts the focal position of an optical system, a drive unit that drives the focus lens so as to move in the optical axis direction, and the drive unit. It has a specific position different from the target position for moving the focus lens, and a drive control unit that drives and controls the drive unit based on the current position of the focus lens.

Claims (19)

A focus lens that adjusts the focal position of the optical system,
A drive unit that drives the focus lens to move in the optical axis direction,
A drive control unit that drives and controls the drive unit based on a specific position based on a target position for moving the focus lens by the drive unit and the current position of the focus lens.
Lens barrel with. The lens barrel according to claim 1.
It has a calculation unit that calculates the specific position based on the target position, the image plane speed of the subject, and a predetermined time.
The drive control unit is a lens barrel that drives and controls the drive unit based on the specific position calculated by the calculation unit and the current position. The lens barrel according to claim 2.
The predetermined time is a delay time that is a time interval after giving a drive start instruction to the drive unit. The lens barrel according to claim 3.
The delay time is a time determined based on the characteristics of the focus lens, the lens barrel. The lens barrel according to claim 2.
The calculation unit calculates the specific position when the target position and the image plane velocity are received from the camera body communicably connected to the lens barrel. The lens barrel according to claim 2.
When the calculation unit receives an offset amount, which is the difference between the position of the image sensor and the position of the image plane of the subject, and the image plane velocity from the camera body communicably connected to the lens barrel. A lens barrel that calculates the target position using the offset amount and the current position to calculate the specific position. The lens barrel according to claim 1.
The drive control unit is a lens barrel that controls to continue driving the drive unit when the specific position is located on the infinity side of the current position. The lens barrel according to claim 1.
The drive control unit is a lens barrel that controls to stop driving the drive unit when the specific position is not located on the infinity side of the current position. The lens barrel according to claim 8.
The drive control unit is a lens barrel that controls to start driving the drive unit when the specific position is located on the infinity side of the current position while the drive unit is stopped. The lens barrel according to claim 1.
The drive control unit is a lens barrel that sets the specific position to a position further away from infinity when a moving image shooting mode for shooting a moving image of a subject is set. The lens barrel according to claim 1.
The drive control unit sets the first specific position when the first volume is detected to a position closer to the second specific position when a second volume smaller than the first volume is detected. , Lens barrel. The lens barrel according to claim 1.
It has a detector that detects a specific event,
The drive control unit is a lens barrel that drives and controls the drive unit based on a specific event detected by the detection unit. The lens barrel according to claim 12.
It has a calculation unit that calculates the specific position based on the target position, the image plane velocity of the subject, a predetermined time, and a coefficient related to the specific event.
The drive control unit is a lens barrel that drives and controls the drive unit based on the specific position calculated by the calculation unit and the current position. The lens barrel according to claim 13.
The calculation unit is a lens barrel that calculates the specific position based on the volume from the outside. A focus lens that adjusts the focal position of the optical system,
A drive unit that moves the focus lens in the optical axis direction,
A drive control unit that drives and controls the drive unit based on a second position based on a first position for moving the focus lens by the drive unit and a position of the focus lens.
Lens barrel with. A focus lens that adjusts the focal position of the optical system,
A drive unit that moves the focus lens in the optical axis direction,
The third position based on the second position, which is the second position for moving the focus lens from the first position and is different depending on the time, and the position of the focus lens when the focus lens is moved. Based on the drive control unit that drives and controls the drive unit,
Lens barrel with. The lens barrel according to claim 1 and
It has a camera body that is communicably connected to the lens barrel.
The camera body is an imaging device that calculates the target position and the image plane velocity of the subject based on the current position and transmits the calculation to the lens barrel. The lens barrel according to claim 1 and
It has a camera body that is communicably connected to the lens barrel.
Based on the current position, the camera body calculates an offset amount, which is the difference between the position of the image sensor and the position of the image plane of the subject, and the image plane speed of the subject, and transmits the offset amount to the lens barrel. Image sensor. A focus lens that adjusts the focal position of the optical system,
A drive unit that drives the focus lens to move in the optical axis direction,
A drive control unit that drives and controls the drive unit based on a specific position based on a target position for moving the focus lens by the drive unit and the current position of the focus lens.
An imaging device having.

Images