Controller, lens device, imaging apparatus, control method, and program

Abstract

To provide a controller that can more appropriately control the drive of a plurality of lenses.SOLUTION: A controller (106) controls a first optical element and a second optical element movable in an optical axis direction, and has: control means (106b, 106e) that move at least one of the first optical element and the second optical element to a target position; and correction means (106d) that moves the first optical element or the second optical element in the optical axis direction to correct a control error in the target position. The correction means can switch between the first optical element and the second optical element to be used in correcting the control error in the target position.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a control device, a lens device, an imaging device, a control method, and a program. [Background technology]

[0002] Conventionally, lens devices that drive multiple lenses, such as zoom lenses or focus lenses, by motor control are known. When moving the multiple lenses, it is desirable to perform correction drive to reduce control errors of the multiple lenses. Patent Document 1 discloses a lens device that performs correction drive to move a second focus lens with higher resolution to cancel out focus deviation caused by position deviation of a first focus lens with lower resolution. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-073584 Summary of the Invention [Problem to be solved by the invention]

[0004] However, depending on the conditions, the correction drive disclosed in Patent Document 1 may not be desirable.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a control device that can more appropriately control the driving of a plurality of lenses. [Means for solving the problem]

[0006] A control device according to one aspect of the present invention is a control device that controls a first optical element and a second optical element that are movable in the optical axis direction, and includes a control means that moves at least one of the first optical element and the second optical element to a target position, and a correction means that moves the first optical element or the second optical element in the optical axis direction to correct a control error at the target position, and the correction means is capable of switching between using either the first optical element or the second optical element to correct the control error at the target position.

[0007] Other objects and features of the present invention are illustrated in the following examples. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a control device that can more appropriately control the driving of a plurality of lenses. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a configuration diagram of an imaging system according to a first embodiment. [Figure 2] FIG. 2 is a configuration diagram of a lens control unit according to the first embodiment. [Figure 3] 5A and 5B are explanatory diagrams of a method for switching the corrective drive lens in the first embodiment. [Figure 4] 10 is a flowchart of a method for switching the corrective drive lens in the first embodiment. [Figure 5] 10 is an explanatory diagram of a method for switching the corrective drive lens in the second embodiment. FIG. [Figure 6] 10 is a flowchart of a method for switching the corrective drive lens in the second embodiment. [Figure 7] 10A and 10B are explanatory diagrams of a method for switching the corrective drive lens in the third embodiment. [Figure 8] 11 is a flowchart of a method for switching the corrective drive lens in the third embodiment. [Figure 9] 10 is an explanatory diagram of a method for switching the corrective drive lens in the fourth embodiment. FIG. [Figure 10]10 is a flowchart of a method for switching the corrective drive lens in the fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same components are designated by the same reference numerals, and redundant explanations will be omitted. [Example]

[0011] First, with reference to FIG. 1, an imaging system 10 according to a first embodiment of the present invention will be described. FIG. 1 is a configuration diagram of the imaging system 10. The imaging system 10 is an interchangeable-lens camera system including an imaging device (camera body) 200 and a lens device (interchangeable lens) 100 that is detachable from the imaging device 200. The imaging device 200 and the lens device 100 are mechanically and electrically connected via a mount (not shown). The imaging device 200 supplies power to the lens device 100 via a power terminal unit provided on the mount (not shown). The imaging device 200 communicates with the lens device 100 via a communication terminal unit provided on the mount (not shown). However, this embodiment is not limited to this and can also be applied to an imaging device in which the camera body and the lens device are integrally configured.

[0012] The imaging device 200 includes an imaging element 201 , a signal processing unit 202 , a recording processing unit 203 , a defocus detection unit 204 , a camera control unit 205 , a memory 206 , an operation unit 207 , and a display unit 208 .

[0013] The image sensor 201 receives light from the optical system 101, generates an electrical signal (analog signal) by photoelectric conversion, and outputs it to a signal processing unit 202. The image sensor 201 has pixels for capturing images (imaging pixels) as well as pixels for detecting a focus position (focus detection pixels, not shown). The signal processing unit 202 converts the electrical signal (analog signal) from the image sensor 201 into a digital signal. The signal processing unit 202 also performs various image processing on the digital signal, such as noise removal and color correction, and outputs the digital signal to a recording processing unit 203. The recording processing unit 203 records the input image and displays the image on a display unit 208. The defocus detection unit 204 detects the focus state of the subject image using the image sensor 201.

[0014] The imaging system 10 of this embodiment detects the defocus amount using a phase difference detection method. The defocus detection unit 204 detects the phase difference between signals of a pair of subject images obtained from light incident on focus detection pixels of the image sensor 201 via a microlens that performs pupil division, and determines the defocus amount corresponding to the phase difference. The defocus detection unit 204 then outputs the detected defocus amount to the camera control unit 205.

[0015] The camera control unit 205 is a computer having a CPU (Central Processing Unit) and is electrically connected to the defocus detection unit 204, memory 206, and operation unit 207. The camera control unit 205 reads and executes programs recorded in the memory 206. The camera control unit 205 also communicates information related to the camera type, information necessary for autofocus control, and the like with the lens control unit 106. The camera control unit 205 also controls the imaging device 200 in response to input from a camera operation unit including an imaging instruction switch and various setting switches (not shown). The camera control unit 205 also controls a mechanical shutter (not shown) to adjust the amount of exposure to the image sensor 201 in response to a shutter mode set via the operation unit 207. The camera control unit 205 also generates a drive command for the focus lens based on the detection result from the defocus detection unit 204 and the current position of the focus lens acquired from the attached lens device 100.

[0016] Lens device 100 has an optical system 101 capable of forming an optical image of a subject on an image sensor 201 of an image pickup device 200. Optical system 101 has, in order from the subject side to the image side, a field lens 102, a variable magnification lens (zoom lens, i.e., a lens that moves during zooming) 103, an aperture unit 104, and a focus lens (lens that moves during focusing) 105. In this embodiment, lens device 100 is a zoom lens with a variable focal length.

[0017] The field lens 102 adjusts the direction of travel of peripheral light in the subject image. After an operation by a zoom operation unit 112 is detected by an operation amount detection unit 113, the variable magnification lens 103 moves in the optical axis direction by driving an actuator such as an ultrasonic motor via a zoom drive unit 107, thereby changing the focal length of the lens device 100. The position of the variable magnification lens 103 is detected by a zoom position detection unit 108. The diaphragm unit 104 is configured with diaphragm blades (not shown), and adjusts the amount of light by driving an actuator such as a stepping motor via an diaphragm drive unit 109. The focus lens 105 is moved in the optical axis direction by driving an actuator such as an ultrasonic motor via a focus drive unit 110, thereby adjusting the focus state, and the position is detected by a focus position detection unit 111.

[0018] The memory 114 is a storage means for storing information, and is configured using a ROM (Read Only Memory), a RAM (Random Access Memory), or the like. The memory 114 stores information indicating the relationship between the design positions of the variable magnification lens 103 and the focus lens 105 and the subject distance and the focal length. The memory 114 also stores information indicating the relationship between optical information such as the focus sensitivity and aberration sensitivity of the variable magnification lens 103 and the focus lens 105 and the subject distance and the focal length. The memory 114 also stores information indicating the relationship between the correction limit amount of the variable magnification lens 103 and the focus lens 105 and the subject distance and the focal length.

[0019] The lens control unit 106 is a computer having a CPU and is electrically connected to a zoom driving unit 107, an aperture driving unit 109, a zoom position detection unit 108, a focus driving unit 110, a focus position detection unit 111, and a memory 114.

[0020] Lens control unit 106 receives a control command from camera control unit 205 and outputs a command to focus drive unit 110 so that focus lens 105 is driven at a predetermined drive amount and drive speed based on the received control command. Focus drive unit 110 drives focus lens 105 and performs a focus adjustment operation in accordance with the command from lens control unit 106. This series of lens control modes is called an autofocus control mode.

[0021] The lens control unit 106 detects via the operation amount detection unit 113 that the zoom operation unit 112 has been operated. Then, using the signal from the operation amount detection unit 113, the lens control unit 106 outputs a command to the zoom drive unit 107 to drive the variable magnification lens 103 at a drive amount and drive speed that correspond to the operation direction and amount of the zoom operation unit 112. As the variable magnification lens 103 moves, the focal length changes, and the focus position at which the lens is in focus changes. Therefore, the focus drive unit 110 drives the focus lens 105 in accordance with a command from the lens control unit 106, based on the design position information stored in the memory 114, and also performs a focus adjustment operation. This series of lens control modes is called the zoom control mode.

[0022] Next, the lens control unit 106 in this embodiment will be described with reference to Fig. 2. Fig. 2 is a configuration diagram of the lens control unit 106. The lens control unit 106 is a control device that controls a first optical element (e.g., a variable magnification lens 103) and a second optical element (e.g., a focus lens 105) that are movable in the optical axis direction. The lens control unit 106 has a target position generation unit 106a, a zoom control unit 106b, a correction value calculation unit 106c, a switching unit 106d, and a focus control unit 106e. Note that in Fig. 2, the aperture drive unit 109 is omitted in order to focus on focus control.

[0023] The target position generating unit 106a generates a zoom target position and a focus target position at a predetermined control cycle based on the drive amount output from the camera control unit 205 or the operation amount detecting unit 113 to the lens control unit 106. In this embodiment, the target positions are generated so that the zoom target position and the focus target position have the same focal length and the same subject distance, respectively.

[0024] The zoom control unit 106b calculates a zoom position deviation (the difference between the zoom target position and the actual zoom position) based on the zoom target position acquired via the target position generation unit 106a and the actual zoom position acquired via the zoom position detection unit 108. When the zoom correction value Cx is output from the correction value calculation unit 106c, the zoom control unit 106b adds the zoom correction value Cx to the zoom position deviation. The zoom control unit 106b outputs the calculated zoom position deviation to the switching unit 106d. The zoom control unit 106b also converts the calculated zoom position deviation into a zoom operation amount by multiplying the calculated zoom position deviation by, for example, a PID gain, and outputs the converted amount to the zoom drive unit 107.

[0025] The correction value calculation unit 106c calculates a correction value based on the zoom position deviation calculated by the zoom control unit 106b or the focus position deviation calculated by the focus control unit 106e, and the zoom focus sensitivity and focus sensitivity stored in the memory 114. When correction is performed by the zoom control unit 106b, the correction value calculation unit 106c calculates a zoom correction value Cx using the following equation (1) based on the focus position deviation ΔDy, the zoom focus sensitivity α, and the focus sensitivity β.

[0026] Cx=ΔDy·(α / β) (1) When the focus control unit 106e performs correction, the correction value calculation unit 106c calculates a focus correction value Cy using the following equation (2) based on the zoom position deviation ΔDx, the zoom focus sensitivity α, and the focus focus sensitivity β.

[0027] Cy=ΔDx (β / α) (2) The switching unit 106d inputs the zoom position deviation and the focus position deviation to the correction value calculation unit 106c. Then, the switching unit 106d switches whether to output the zoom correction value Cx or the focus correction value Cy calculated by the correction value calculation unit 106c to the zoom control unit 106b or the focus control unit 106e depending on the conditions. The conditions for switching will be described later.

[0028] The focus control unit 106e calculates a focus position deviation (the difference between the focus target position and the focus actual position) based on the focus target position acquired by the target position generation unit 106a and the focus actual position acquired by the focus position detection unit 111. When the focus correction value Cy is output from the correction value calculation unit 106c, the focus control unit 106e adds the focus correction value Cy to the focus position deviation. The focus control unit 106e outputs the calculated focus position deviation to the switching unit 106d. The focus control unit 106e also converts the calculated focus position deviation into a focus operation amount to be output to the focus drive unit 110 by multiplying the calculated focus position deviation by, for example, a PID gain or the like, and outputs the converted amount to the focus drive unit 110.

[0029] The zoom control unit 106b and the focus control unit 106e function as control means for moving at least one of the first optical element and the second optical element to a target position. The switching unit 106d functions as correction means for correcting the target position (control error of the target position) by moving one of the first optical element or the second optical element in the optical axis direction. The switching unit (correction means) 106d also switches between the first optical element and the second optical element to be used to correct the target position (control error of the target position).

[0030] 3(a) and 3(b), a method for switching the correction drive lens based on the drive amount in this embodiment will be described. Note that in this embodiment, the zoom lens (variable lens 103) is described as having lower focus sensitivity than the focus lens 105, but this is not limiting.

[0031] Figure 3(a) is an explanatory diagram of the time series results when corrective driving is performed on a zoom lens. In Figure 3(a), the horizontal axis represents time, and the vertical axis represents focus position and zoom position. Here, as in the past, the focus sensitivity of the focus lens and the zoom lens are compared, and corrective driving is performed on the zoom lens with the lower sensitivity.

[0032] First, at time t1, driving of the zoom lens is completed. Then, at time t2, driving of the focus lens is completed. Then, a correction drive value is calculated based on the determined focus position deviation and the focus sensitivity ratio between the focus lens and zoom lens, and correction drive is performed on the zoom lens until time t3. At this time, correction drive is performed on a lens with lower focus sensitivity, so a larger correction drive value is calculated, making it possible to correct image plane errors with finer resolution. However, because the correction drive value is determined at time t2 and correction drive is completed at time t3, extra drive time is required for the correction drive.

[0033] Figure 3(b) is an explanatory diagram of the time series results when corrective driving is performed on the focus lens. In Figure 3(b), the horizontal axis represents time, and the vertical axis represents focus position and zoom position. Here, the focus drive amount and zoom drive amount are compared, and corrective driving is performed on the focus lens with the larger drive amount.

[0034] Because the zoom lens has a smaller drive amount, at time t4, the zoom lens completes drive before the focus lens. Based on the determined zoom position deviation and the focus sensitivity ratio between the focus lens and zoom lens, a correction drive value is calculated, and the focus lens is subjected to correction drive until time t5. In this way, by performing correction drive on the lens with a larger drive amount and slower drive completion based on a correction drive value calculated based on the lens with a smaller drive amount and faster drive completion, it may be possible to shorten the drive time.

[0035] Next, a method for switching the corrective drive lens based on the drive amount in this embodiment will be described with reference to Fig. 4. Fig. 4 is a flowchart of the method for switching the corrective drive lens. Each step in Fig. 4 is mainly executed by the lens control unit 106.

[0036] First, in step S101, the lens control unit 106 acquires the focus sensitivity of each lens, i.e., the focus sensitivity and the zoom sensitivity, via the memory 114. Next, in step S102, the lens control unit 106 determines whether the zoom drive amount (first drive amount) is greater than the focus drive amount (second drive amount). If it is determined that the zoom drive amount is greater than the focus drive amount, the process proceeds to step S103. On the other hand, if it is determined that the zoom drive amount is not greater than the focus drive amount, the process proceeds to step S104.

[0037] In step S103, the lens control unit 106 calculates a correction value (correction drive value) based on the focus position deviation and the ratio (sensitivity ratio) between the focus sensitivity and the zoom sensitivity. Subsequently, in step S105, the lens control unit 106 adds the correction drive value to the zoom position deviation. Subsequently, in step S106, the lens control unit 106 multiplies the zoom position deviation to which the correction drive value has been added in step S105 by a PID gain or the like to convert it into a zoom operation amount to be output to the zoom drive unit 107. Then, the lens control unit 106 outputs the zoom operation amount to the zoom drive unit 107 and drives the variable magnification lens 103 (performing correction drive with the zoom lens as the first optical element).

[0038] In step S104, the lens control unit 106 calculates a correction value (correction drive value) based on the zoom position deviation and the ratio (sensitivity ratio) between the zoom focus sensitivity and the focus focus sensitivity. Subsequently, in step S107, the lens control unit 106 adds the correction drive value to the focus position deviation. Subsequently, in step S108, the lens control unit 106 multiplies the focus position deviation to which the correction drive value has been added in step S107 by a PID gain or the like to convert it into a focus operation amount to be output to the focus drive unit 110. Then, the lens control unit 106 outputs the focus operation amount to the focus drive unit 110 and drives the focus lens 105 (performing correction drive with the focus lens as the second optical element).

[0039] As described above, in this embodiment, the switching unit 106d switches whether to use the first optical element or the second optical element to correct the target position, depending on the first drive amount of the first optical element and the second drive amount of the second optical element. Preferably, when the first drive amount is greater than the second drive amount, the switching unit 106d corrects the target position using the first optical element. On the other hand, when the second drive amount is greater than the first drive amount, the switching unit 106d corrects the target position using the second optical element.

[0040] In this embodiment, the lens to be corrected is switched according to the drive amount. However, this is not limiting. The lens to be corrected may be switched according to the power-on state. For example, the power-on state may determine that the zoom lens has completed its drive first, and the focus lens may be corrected. That is, the switching unit 106d may switch whether to use the first optical element or the second optical element to correct the target position according to the first power-on state of the first optical element and the second power-on state of the second optical element. More preferably, when the first power-on state is powered and the second power-on state is not powered, the switching unit 106d corrects the target position using the first optical element. On the other hand, when the second power-on state is powered and the first power-on state is not powered, the switching unit 106d corrects the target position using the second optical element. [Example]

[0041] Next, a second embodiment of the present invention will be described. In this embodiment, the lens that is to be driven for correction is switched depending on the amount of correction possible. In this embodiment, the focus sensitivity of the zoom lens (variable lens 103) is described as being lower than the focus sensitivity of the focus lens 105. In this embodiment, the aberration sensitivity of the focus lens 105 is described as being lower than the aberration sensitivity of the zoom lens (variable lens 103). However, this embodiment is not limited to this.

[0042] In this embodiment, when the variable magnification lens 103 and the focus lens 105 move toward the image sensor, a focus state is obtained for a subject on the close side, whereas when the variable magnification lens 103 and the focus lens 105 move toward the subject, a focus state is obtained for a subject on the infinity side.

[0043] A method for switching the correction drive lens based on the correction possible amount in this embodiment will be described with reference to Figures 5(a) and (b). Figure 5(a) is an explanatory diagram of an example in which correction drive is performed with a zoom lens with lower focus sensitivity. Figure 5(a) shows a zoom target position 5a and an actual zoom position 5b, which are positions on the optical axis 5, as well as a zoom position deviation 5c, which is the difference between them. Also shown are a focus target position 6a and an actual focus position 6b, as well as a focus position deviation 6c.

[0044] Here, zoom target position 5a and focus target position 6a are positions where the focal length and subject distance are the same and an in-focus state is obtained. At this time, focus lens 105 is shifted toward infinity from focus target position 6a by focus position deviation 6c, so the subject image is formed at a position shifted toward infinity on image sensor 201, resulting in out-of-focus.

[0045] Therefore, the lens control unit 106 (correction value calculation unit 106c) can correct the focus error caused by the control error of the focus lens 105 by correctively driving the variable magnification lens 103 by the zoom correction value Cx that can be calculated based on equation (1).

[0046] However, if the variable magnification lens 103 is shifted too far from the zoom target position 5a for correction drive, it is conceivable that large spherical aberration will occur, so it is desirable to perform correction within the zoom correction limit range 5f that does not affect the aberration. In this case, a focus error equivalent to a correction residual error 5h will occur with respect to the original zoom correction value Cx.

[0047] 5B is an explanatory diagram of an example in which correction drive is performed with a focus lens with higher focus sensitivity. In FIG. 5B, the variable magnification lens 103 is shifted toward infinity by a zoom position deviation 5c from the zoom target position 5a. As a result, the subject image is formed at a position shifted toward infinity on the image sensor 201, resulting in focus deviation.

[0048] Therefore, the lens control unit 106 (correction value calculation unit 106c) can correct the focus shift caused by the control error of the variable magnification lens 103 by driving the focus lens 105 for the focus correction value Cy that can be calculated based on equation (2).

[0049] Furthermore, in this embodiment, because the focus lens has lower aberration sensitivity, it is possible to set a focus correction limit range 6f that is larger than the zoom correction limit range 5f and does not affect aberrations. Therefore, there are cases where focus deviation can be suppressed more effectively than when correcting a zoom lens with low focus sensitivity without generating a correction residual.

[0050] Here, a method for comparing the correctable amounts of the zoom lens and the focus lens will be described. First, when the zoom correction value Cx calculated by equation (1) is greater than the zoom correction limit amount Lx stored in the memory 114, the zoom correction residual ΔRx is calculated by the following equation (3).

[0051] ΔRx=Cx-Lx (3) Next, the focus error ΔPx when corrected by the zoom lens is calculated using the zoom correction residual ΔRx calculated using equation (3) and the zoom focus sensitivity α using equation (4) below.

[0052] ΔPx=|ΔRx·α| (4) Similarly, when the focus correction value Cy calculated by equation (2) is greater than the focus correction limit amount Ly stored in the memory 114, the focus correction residual ΔRy is calculated by the following equation (5).

[0053] ΔRy = Cy - Ly (5) Next, the focus deviation ΔPy when corrected by the focus lens is calculated by the following equation (6) using the focus correction residual ΔRy calculated by equation (5) and the focus sensitivity β.

[0054] ΔPy=|ΔRy·β| (6) Next, the focus error ΔPx when corrected using the zoom lens calculated using equation (4) is compared with the focus error ΔPy when corrected using the focus lens calculated using equation (6).Then, it is determined that the focus error can be reduced more effectively by a larger amount, and the correction drive lens can be switched accordingly.

[0055] Next, a method for switching the corrective drive lens based on the correctable amount in this embodiment will be described with reference to Fig. 6. Fig. 6 is a flowchart of the method for switching the corrective drive lens based on the correctable amount. Each step in Fig. 6 is mainly executed by the lens control unit 106.

[0056] First, in step S201, the lens control unit 106 acquires the focus sensitivity and the zoom sensitivity via the memory 114. Subsequently, in step S202, the lens control unit 106 acquires the focus correction limit amount Ly and the zoom correction limit amount Lx via the memory 114.

[0057] Next, in step S203, the lens control unit 106 calculates a zoom correction value Cx from the focus position deviation and the ratio between the focus sensitivity and the zoom sensitivity based on equation (1). Next, in step S204, the lens control unit 106 calculates a focus correction value Cy from the zoom position deviation and the ratio between the focus sensitivity and the zoom sensitivity based on equation (2).

[0058] Next, in step S205, the lens control unit 106 calculates the defocus ΔPx when corrected by the zoom lens based on equations (3) and (4).The lens control unit 106 also calculates the defocus ΔPy when corrected by the focus lens based on equations (5) and (6).

[0059] Next, in step S206, the lens control unit 106 compares the focus error ΔPx when corrected using the zoom lens with the focus error ΔPy when corrected using the focus lens. If the focus error ΔPx when corrected using the zoom lens is smaller, the lens control unit 106 determines that the correctable amount of the zoom lens (first correctable amount) is greater than the correctable amount of the focus lens (second correctable amount), and proceeds to step S207. On the other hand, if the focus error ΔPy when corrected using the focus lens is smaller, the lens control unit 106 determines that the correctable amount of the focus lens (second correctable amount) is greater than the correctable amount of the zoom lens (first correctable amount), and proceeds to step S208.

[0060] In step S207, the lens control unit 106 adds the zoom correction value Cx to the zoom position deviation. Subsequently, in step S209, the lens control unit 106 multiplies the zoom position deviation to which the correction drive value has been added in step S207 by a PID gain or the like to convert it into a zoom operation amount to be output to the zoom drive unit 107. Then, the lens control unit 106 outputs the zoom operation amount to the zoom drive unit 107 and drives the variable magnification lens 103 (performing correction drive with the zoom lens as the first optical element).

[0061] In step S208, the lens control unit 106 adds the focus correction value Cy to the focus position deviation. Subsequently, in step S210, the lens control unit 106 multiplies the focus position deviation to which the correction drive value has been added in step S208 by a PID gain or the like to convert it into a focus operation amount to be output to the focus drive unit 110. Then, the lens control unit 106 outputs the focus operation amount to the focus drive unit 110 to drive the focus lens 105 (performing correction drive with the focus lens as the second optical element).

[0062] As described above, in this embodiment, the switching unit 106d switches whether to use the first optical element or the second optical element to correct the target position, depending on the first correctable amount of the first optical element and the second correctable amount of the second optical element. Preferably, when the first correctable amount is greater than the second correctable amount, the switching unit 106d corrects the target position using the first optical element. On the other hand, when the second correctable amount is greater than the first correctable amount, the switching unit 106d corrects the target position using the second optical element.

[0063] In this embodiment, the first correctable amount and the second correctable amount are each limited amounts based on the target position, and may be varied, for example, depending on the subject distance, the focal length, or the position of at least one of the first optical element and the second optical element.

[0064] In this embodiment, the lens to be driven for correction is switched according to the correctable amount, but the lens to be driven for correction may also be switched according to the subject distance, focal length, lens position, aberration sensitivity, etc. For example, since the magnitude of aberration fluctuation due to lens movement can be estimated according to the subject distance, the lens to be driven for correction may be switched between subject distances of 1 m to 3 m and 3 m to 10 m. Similarly, the lens to be driven for correction may also be switched based on the focal length, lens position, or the magnitude of aberration sensitivity stored in memory 114. [Example]

[0065] Next, a third embodiment of the present invention will be described. In this embodiment, the lens to be corrected is switched depending on the position deviation. In this embodiment, the zoom lens is described as having lower focus sensitivity than the focus lens, but the present invention is not limited to this. In this embodiment, the focus lens is described as having higher resistance to disturbances such as impacts than the zoom lens, but the present invention is not limited to this. In this embodiment, an example will be described in which the actual zoom position changes significantly (zoom position deviation increases) due to disturbance factors such as impacts.

[0066] An example of a method for switching the correction drive lens based on the position deviation will be described with reference to Figures 7(a) and (b). Figure 7(a) is an explanatory diagram of the time series results when correction drive is performed with a zoom lens. In Figure 7(a), the horizontal axis represents time, and the vertical axis represents the focus position and zoom position, respectively. Here, as in the past, the focus sensitivity of the focus lens and the zoom lens are compared, and correction drive is performed with the zoom lens with the lower sensitivity.

[0067] First, at time t1, an external disturbance such as an impact causes a large change in the actual zoom position. Next, at time t2, the focus lens drive is completed, and a correction drive value is calculated based on the determined focus position deviation and the focus sensitivity ratio between the focus lens and zoom lens, and correction drive is performed on the zoom lens. However, due to the disturbance that occurred at time t1, a deviation occurs between the zoom correction target position and the actual zoom position, and the intended correction drive is not performed, and the focus error is not reduced.

[0068] FIG. 7(b) is an explanatory diagram of the time-series results when corrective driving is performed on the focus lens. In FIG. 7(b), the horizontal axis represents time, and the vertical axis represents focus position and zoom position. At time t3, the actual zoom position changes significantly due to a disturbance such as an impact. After time t4, it can be inferred that a disturbance such as an impact has occurred by detecting that the zoom position deviation is equal to or greater than a predetermined value. Therefore, after driving of the focus lens is completed at time t4, a corrective drive value is calculated based on the zoom position deviation and the focus sensitivity ratio between the focus lens and the zoom lens, and corrective driving is performed on the focus lens.

[0069] In this way, when the position deviation is large and correction drive is difficult to perform due to disturbances such as impact, it may be possible to reduce focus deviation through stable correction drive by performing correction drive on the other lens with a smaller position deviation.

[0070] Next, a method for switching the corrective drive lens based on the position deviation in this embodiment will be described with reference to Fig. 8. Fig. 8 is a flowchart of the method for switching the corrective drive lens based on the position deviation. Each step in Fig. 8 is mainly executed by the lens control unit 106.

[0071] First, in step S301, the lens control unit 106 acquires the focus sensitivity and the zoom sensitivity via the memory 114. Next, in step S302, the lens control unit 106 determines whether the focus position deviation (first position deviation) is greater than a predetermined value. If it is determined that the focus position deviation is greater than the predetermined value, the process proceeds to step S303. On the other hand, if it is determined that the focus position deviation is not greater than the predetermined value, the process proceeds to step S304.

[0072] In step S303, the lens control unit 106 calculates a correction value (correction drive value) from the focus position deviation and the ratio between the focus sensitivity and the zoom sensitivity. Subsequently, in step S305, the lens control unit 106 adds the correction drive value to the zoom position deviation. Subsequently, in step S306, the lens control unit 106 multiplies the zoom position deviation to which the correction drive value has been added in step S305 by a PID gain or the like to convert it into a zoom operation amount to be output to the zoom drive unit 107. Then, the lens control unit 106 outputs the zoom operation amount to the zoom drive unit 107 and drives the variable magnification lens 103 (performing correction drive with the zoom lens as the first optical element).

[0073] In step S304, the lens control unit 106 calculates a correction value (correction drive value) from the zoom position deviation and the ratio between the zoom focus sensitivity and the focus focus sensitivity. Subsequently, in step S307, the lens control unit 106 adds the correction drive value to the focus position deviation. Subsequently, in step S308, the lens control unit 106 multiplies the focus position deviation to which the correction drive value has been added in step S307 by a PID gain or the like to convert it into a focus operation amount to be output to the focus drive unit 110. Then, the lens control unit 106 outputs the focus operation amount to the focus drive unit 110 and drives the focus lens 105 (performing correction drive with the focus lens as the second optical element).

[0074] As described above, in this embodiment, the switching unit 106d switches whether to use the first optical element or the second optical element to correct the target position, depending on at least one of the first position deviation of the first optical element and the second position deviation of the second optical element. Preferably, when the first position deviation is smaller than a predetermined value, the switching unit 106d corrects the target position using the first optical element. On the other hand, when the first position deviation is larger than the predetermined value, the switching unit 106d corrects the target position using the second optical element.

[0075] Alternatively, the lens to be driven for correction may be switched depending on whether the second position deviation of the second optical element is greater than a predetermined value. That is, when the second position deviation is smaller than the predetermined value, the switching unit 106d corrects the target position using the second optical element. On the other hand, when the second position deviation is greater than the predetermined value, the switching unit 106d corrects the target position using the first optical element.

[0076] Alternatively, the lens to be driven for correction may be switched depending on the magnitude relationship between the first position deviation of the first optical element and the second position deviation of the second optical element. That is, when the first position deviation is smaller than the second position deviation, the switching unit 106d corrects the target position using the first optical element. On the other hand, when the second position deviation is smaller than the first position deviation, the switching unit 106d corrects the target position using the second optical element.

[0077] In this embodiment, the lens to be subjected to the correction drive is switched in accordance with the position deviation, but the lens to be subjected to the correction drive may also be switched based on the attached camera information (the type of image capture device 200 attached to the lens apparatus 100) received from the camera control unit 205. For example, if it is expected that the combination with the attached image capture device 200 is susceptible to external disturbance factors such as impact, the lens to be subjected to the correction drive may be switched.

[0078] Furthermore, the lens to be subjected to the correction drive may be switched depending on the shutter mode received from the camera control unit 205. For example, in the shutter mode of the camera body, when the mechanical shutter is driven, it is expected that an impact will occur due to the shutter drive, so the lens to be subjected to the correction drive may be switched.

[0079] Furthermore, the lens that performs the correction drive may be switched depending on the attitude, temperature, or number of drives of the lens device or camera body. For example, if the operation during the correction drive is affected by the attitude, temperature, or number of drives, the correction drive may be switched to a lens that is less affected. [Example]

[0080] Next, a fourth embodiment of the present invention will be described. In this embodiment, the lens to be subjected to correction drive is switched depending on the lens control mode. Note that in this embodiment, the zoom lens is described as having lower focus sensitivity than the focus lens, but the present invention is not limited to this.

[0081] An example of switching the corrective drive lens based on the lens control mode in this embodiment will be described with reference to Figures 9(a) and (b). Figure 9(a) is an explanatory diagram of the time series results when corrective drive is performed on the zoom lens in autofocus control mode. In Figure 9(a), the horizontal axis represents time, and the vertical axis represents the focus position and zoom position, respectively. In autofocus control mode, the focal length is fixed, and first only the focus lens is driven so that the target subject is in focus.

[0082] After the focus lens has been driven at time t1, it is considered to perform correction drive using the lower-sensitivity zoom lens. Therefore, based on the focus position deviation determined at time t1 and the focus sensitivity ratio between the focus lens and the zoom lens, a correction drive value is calculated and correction drive is performed using the zoom lens. In this way, in autofocus control mode, if the zoom lens has lower focus sensitivity, it is preferable to perform correction drive using the zoom lens as in the past.

[0083] FIG. 9(b) is an explanatory diagram of the time series results when corrective driving is performed on the focus lens in zoom control mode. In FIG. 9(b), the horizontal axis represents time, and the vertical axis represents focus position and zoom position. In zoom control mode, the zoom lens is driven in accordance with changes in focal length due to zoom operation. Furthermore, if the change in focal length also changes the focus position at which the image is in focus, the focus lens is also driven to a predetermined position. In this case, after the zoom operation is completed, the zoom lens stops driving and the focus target position at which the image is in focus is calculated based on the determined focal length. Therefore, it is expected that the focus lens will complete its driving later. Therefore, performing corrective driving on a focus lens with high focus sensitivity is likely to shorten the driving time.

[0084] 9(b), at time t2, after the driving of the zoom lens is completed, a correction drive value is calculated based on the zoom position deviation and the focus sensitivity ratio between the focus lens and the zoom lens, and correction drive is performed on the focus lens. In this way, by switching the lens to be subjected to correction drive depending on the lens control mode, it may be possible to shorten the drive time.

[0085] Next, a method for switching the corrective drive lens based on the lens control mode in this embodiment will be described with reference to Fig. 10. Fig. 10 is a flowchart of the method for switching the corrective drive lens based on the lens control mode. The steps in Fig. 10 are mainly executed by the lens control unit 106.

[0086] First, in step S401, the lens control unit 106 acquires the focus sensitivity and the zoom sensitivity via the memory 114. Next, in step S402, the lens control unit 106 determines whether the lens control mode is the autofocus control mode. If it is determined that the lens control mode is the autofocus control mode, the process proceeds to step S403. On the other hand, if it is determined that the lens control mode is not the autofocus control mode, the lens control unit 106 determines that the lens control mode is the zoom control mode, and the process proceeds to step S404.

[0087] In step S403, the lens control unit 106 calculates a correction value (correction drive value) from the focus position deviation and the ratio between the focus sensitivity and the zoom sensitivity. Subsequently, in step S405, the lens control unit 106 adds the correction drive value to the zoom position deviation. Subsequently, in step S406, the lens control unit 106 multiplies the zoom position deviation to which the correction drive value has been added in step S405 by a PID gain or the like to convert it into a zoom operation amount to be output to the zoom drive unit 107. Then, the lens control unit 106 outputs the zoom operation amount to the zoom drive unit 107 and drives the variable magnification lens 103 (performing correction drive with the zoom lens as the first optical element).

[0088] In step S404, the lens control unit 106 calculates a correction value (correction drive value) from the zoom position deviation and the ratio between the zoom focus sensitivity and the focus focus sensitivity. Subsequently, in step S407, the lens control unit 106 adds the correction drive value to the focus position deviation. Subsequently, in step S408, the lens control unit 106 multiplies the focus position deviation to which the correction drive value has been added in step S407 by a PID gain or the like to convert it into a focus operation amount to be output to the focus drive unit 110. Then, the lens control unit 106 outputs the focus operation amount to the focus drive unit 110 and drives the focus lens 105 (performing correction drive with the focus lens as the second optical element).

[0089] As described above, in this embodiment, the switching unit 106d switches between the first optical element and the second optical element to be used to correct the target position according to the lens control mode. The lens control mode is the autofocus control mode or the zoom control mode, but is not limited to these, and the lens to be driven for correction may be switched according to another mode.

[0090] In each embodiment, the first optical element is described as a zoom lens (variable magnification lens 103) and the second optical element is described as a focus lens 105, but this is not limited to this and other lens combinations may be used. For example, the first optical element may be a first zoom lens and the second optical element may be a second zoom lens. That is, the first optical element and the second optical element may be lenses that move during zooming. Or, the first optical element may be a first focus lens and the second optical element may be a second focus lens. That is, the first optical element and the second optical element may be lenses that move during focusing.

[0091] Alternatively, one of the first optical element or the second optical element may be a lens such as the variable magnification lens 103 or the focus lens 105, and the other of the first optical element or the second optical element may be the image sensor 201. In this case, the image sensor 201 is configured to be movable along the optical axis direction. The lens control unit 106 or the camera control unit 205 functions as a control device that controls the first optical element and the second optical element that are movable along the optical axis direction. Both the lens control unit 106 and the camera control unit 205 may cooperate to function as a control device.

[0092] In the above-described embodiments, an example has been described in which, during lens control, both the variable magnification lens 103 as the first optical element and the focus lens 105 as the second optical element move, and either the first optical element or the second optical element is driven for correction depending on the conditions. On the other hand, if either the first optical element or the second optical element is the image sensor 201, it is not necessary for the image sensor 201 to move during lens control. That is, during lens control, correction may be performed by moving only a specific lens in the optical axis direction and then moving the image sensor 201 in the optical axis direction. That is, the control unit may move at least one of the first optical element or the second optical element to a target position, and the correction unit may move either the first optical element or the second optical element in the optical axis direction to correct the target position (control error of the target position).

[0093] (Other Examples) The present invention can also be realized by supplying a program that realizes one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program. It can also be realized by a circuit (e.g., ASIC) that realizes one or more functions.

[0094] According to each embodiment, by switching the lens that performs the correction drive depending on the conditions, it is possible to more stably reduce focus deviation. Therefore, according to each embodiment, it is possible to provide a control device, a lens device, an imaging device, a control method, and a program that can more appropriately control the drive of multiple lenses.

[0095] The disclosure of each embodiment includes the following configurations and methods. (Configuration 1) A control device that controls a first optical element and a second optical element that are movable in an optical axis direction, a control means for moving at least one of the first optical element and the second optical element to a target position; a correction unit that corrects a control error of the target position by moving the first optical element or the second optical element in the optical axis direction, The control device, wherein the correction means is capable of switching between using the first optical element or the second optical element to correct the control error of the target position. (Configuration 2) The control device described in configuration 1, characterized in that the correction means switches whether to use the first optical element or the second optical element to correct the control error of the target position depending on a first drive amount of the first optical element and a second drive amount of the second optical element. (Configuration 3) The correction means When the first driving amount is greater than the second driving amount, the control error of the target position is corrected using the first optical element; 3. The control device according to configuration 2, wherein when the second drive amount is larger than the first drive amount, the control error of the target position is corrected using the second optical element. (Configuration 4) The control device described in configuration 1, characterized in that the correction means switches whether to use the first optical element or the second optical element to correct the control error of the target position depending on a first current-carrying state of the first optical element and a second current-carrying state of the second optical element. (Configuration 5) The correction means When the first energization state is energized and the second energization state is de-energized, the control error of the target position is corrected using the first optical element; The control device according to configuration 4, characterized in that when the second power-on state is power-on and the first power-on state is power-off, the control error of the target position is corrected using the second optical element. (Configuration 6) The control device described in configuration 1, characterized in that the correction means switches whether to use the first optical element or the second optical element to correct the control error of the target position, depending on a first correctable amount of the first optical element and a second correctable amount of the second optical element. (Configuration 7) The correction means If the first correctable amount is greater than the second correctable amount, correcting the control error of the target position using the first optical element; 7. The control device according to configuration 6, wherein when the second correctable amount is greater than the first correctable amount, the control error of the target position is corrected using the second optical element. (Configuration 8) The control device according to configuration 6 or 7, wherein the first correctable amount and the second correctable amount are each limited amounts based on the target position, and vary depending on a subject distance, a focal length, or the position of at least one of the first optical element and the second optical element. (Configuration 9) The control device described in configuration 1, characterized in that the correction means switches whether to use the first optical element or the second optical element to correct the control error of the target position, depending on at least one of a first position deviation of the first optical element or a second position deviation of the second optical element. (Configuration 10) The correction means If the first position deviation is smaller than a predetermined value, correcting the target position using the first optical element; 10. The control device according to configuration 9, wherein when the first position deviation is greater than the predetermined value, the control error of the target position is corrected using the second optical element. (Configuration 11) the control device is provided in a lens device that is detachable from the imaging device, The control device according to configuration 1, characterized in that the correction means switches between using the first optical element or the second optical element to correct the control error of the target position depending on the type of the imaging device. (Configuration 12) The control device according to configuration 1, characterized in that the correction means switches whether to use the first optical element or the second optical element to correct the control error of the target position depending on the shutter mode. (Configuration 13) The control device according to configuration 1, wherein the correction means switches between using the first optical element or the second optical element to correct the control error of the target position depending on the lens control mode. (Configuration 14) the first optical element is a lens that moves during zooming, 14. The control device according to any one of configurations 1 to 13, wherein the second optical element is a lens that moves during focusing. (Configuration 15) 14. The control device according to any one of configurations 1 to 13, wherein the first optical element and the second optical element are lenses that move during zooming. (Configuration 16) 14. The control device according to any one of configurations 1 to 13, wherein the first optical element and the second optical element are lenses that move during focusing. (Configuration 17) the first optical element is a lens; 14. The control device according to any one of configurations 1 to 13, wherein the second optical element is an imaging element. (Configuration 18) 18. A lens device comprising the control device according to any one of configurations 1 to 17 and the first optical element. (Configuration 19) 18. An imaging device comprising the control device according to any one of configurations 1 to 17 and an imaging element. (Method 1) A control method for controlling a first optical element and a second optical element that are movable in an optical axis direction, comprising: a control step of moving at least one of the first optical element and the second optical element to a target position; a correcting step of correcting a control error of the target position by moving the first optical element or the second optical element in the optical axis direction, A control method, characterized in that in the correcting step, it is possible to switch between using the first optical element or the second optical element to correct the control error of the target position. (Configuration 20) A program that causes a computer to execute the control method described in Method 1.

[0096] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist of the present invention. [Explanation of symbols]

[0097] 106 Lens control unit (control device) 106b Zoom control section (control means) 106d Switching unit (correction means) 106e Focus control unit (control means)

Claims

1. A control device that controls a first optical element and a second optical element that are movable in an optical axis direction, a control unit that moves at least one of the first optical element and the second optical element to a target position; a correction unit that corrects a control error of the target position by moving the first optical element or the second optical element in the optical axis direction, The control device according to claim 1, wherein the correction means is capable of switching between using the first optical element or the second optical element to correct the control error of the target position.

2. The control device described in claim 1, characterized in that the correction means switches whether to use the first optical element or the second optical element to correct the control error of the target position depending on a first drive amount of the first optical element and a second drive amount of the second optical element.

3. The correction means When the first driving amount is greater than the second driving amount, the control error of the target position is corrected using the first optical element; 3. The control device according to claim 2, wherein when the second drive amount is greater than the first drive amount, the control error of the target position is corrected using the second optical element.

4. The control device described in claim 1, characterized in that the correction means switches whether to use the first optical element or the second optical element to correct the control error of the target position depending on a first current state of the first optical element and a second current state of the second optical element.

5. The correction means When the first energized state is energized and the second energized state is de-energized, correcting the target position using the first optical element; 5. The control device according to claim 4, wherein when the second energized state is energized and the first energized state is de-energized, the control error of the target position is corrected using the second optical element.

6. 2. The control device according to claim 1, wherein the correction means switches between using the first optical element or the second optical element to correct the control error of the target position depending on a first correctable amount of the first optical element and a second correctable amount of the second optical element.

7. The correction means If the first correctable amount is greater than the second correctable amount, correcting the target position using the first optical element; 7. The control device according to claim 6, wherein when the second correctable amount is greater than the first correctable amount, the control error of the target position is corrected using the second optical element.

8. 7. The control device according to claim 6, wherein the first correctable amount and the second correctable amount are each limited amounts based on the target position, and vary depending on a subject distance, a focal length, or the position of at least one of the first optical element and the second optical element.

9. The control device according to claim 1, characterized in that the correction means switches whether to use the first optical element or the second optical element to correct the control error of the target position depending on at least one of a first position deviation of the first optical element or a second position deviation of the second optical element.

10. The correction means If the first position deviation is smaller than a predetermined value, correcting the target position using the first optical element; 10. The control device according to claim 9, wherein when the first position deviation is greater than the predetermined value, the control error of the target position is corrected using the second optical element.

11. the control device is provided in a lens device that is detachable from the imaging device, 2. The control device according to claim 1, wherein the correction means switches between using the first optical element or the second optical element to correct the control error of the target position depending on the type of the imaging device.

12. 2. The control device according to claim 1, wherein the correction means switches between using the first optical element or the second optical element to correct the control error of the target position depending on a shutter mode.

13. 2. The control device according to claim 1, wherein the correction means switches between using the first optical element or the second optical element to correct the control error of the target position depending on a lens control mode.

14. the first optical element is a lens that moves during zooming, 14. The control device according to claim 1, wherein the second optical element is a lens that moves during focusing.

15. 14. The control device according to claim 1, wherein the first optical element and the second optical element are lenses that move during zooming.

16. 14. The control device according to claim 1, wherein the first optical element and the second optical element are lenses that move during focusing.

17. the first optical element is a lens, The control device according to any one of claims 1 to 13, wherein the second optical element is an imaging element.

18. A lens device comprising: the control device according to claim 1; and the first optical element.

19. An imaging device comprising: the control device according to claim 1; and an imaging element.

20. A control method for controlling a first optical element and a second optical element that are movable in an optical axis direction, the method comprising: a control step of moving at least one of the first optical element and the second optical element to a target position; a correcting step of correcting a control error of the target position by moving the first optical element or the second optical element in the optical axis direction, A control method, characterized in that in the correcting step, it is possible to switch between using the first optical element or the second optical element to correct the control error of the target position.

21. A program causing a computer to execute the control method according to claim 20.

Images