JP2018004890A - Lens device and imaging apparatus including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens device for driving an optical member by a driving part and including driving control means capable of highly accurately driving the optical member to a target position, without hunting, without providing the restrictions of an initialization operation and the driving part.SOLUTION: The lens device includes the optical member, driving means for driving the optical member, detection means for detecting the position of the optical member, target position derivation means for setting the target position to which the optical member is driven, speed derivation means for deriving a target speed for driving the optical member by the driving means on the basis of a difference between the target position and the position of the optical member, and control means for controlling the driving means so as to drive the optical member toward the target position. When at least the optical member is stopped at the target position, the control means controls the drive of the driving means so as to reduce the following capability of the speed of the optical member with respect to the target speed when the speed of the optical member is lower than the target speed compared to when the speed of the optical member is higher than the target speed.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a lens apparatus, and more particularly to a lens apparatus that drives a movable optical member by a driving unit and an imaging apparatus having the lens apparatus.

  In the lens device, it is difficult to accurately drive the optical member to the target position due to control factors such as operating torque and control gain, and environmental factors such as the attitude difference of the lens device and environmental temperature. Therefore, conventionally, an apparatus that stores the convergence correction amount and an apparatus that performs drive control with high accuracy using a special drive unit have been proposed. For example, Patent Document 1 discloses a motor control device that drives an optical member at the time of power activation, detects a position deviation for convergence to a target position, and evaluates convergence based on the detected position deviation. Patent Document 2 discloses a lens device that includes two driving means and stops at the in-focus position with a shape-changing actuator that is finely driven in the vicinity of the in-focus position.

JP 2004-192200 A JP 2003-66312 A

  However, in the apparatus of Patent Document 1, the position deviation used for the convergence evaluation of the target position and the stop position depends only on the attitude difference and the temperature condition when the evaluation value is calculated. For this reason, it cannot cope with changes in shooting conditions. Further, in the apparatus of Patent Document 2, it is necessary to prepare two actuators, which becomes a factor that restricts the driving means of the lens apparatus.

  Therefore, an object of the present invention is to enable the optical member to be driven to a target position with high accuracy without providing an initialization operation or a restriction on the driving unit in the lens device that drives the optical member by the driving unit. It is to provide a lens apparatus provided with a drive control means.

  In order to achieve the above object, the lens device of the present invention includes an optical member, a driving unit that drives the optical member, a detection unit that detects a position of the optical member, and a target position that drives the optical member. Target position deriving means for setting, speed deriving means for deriving a target speed at which the driving means drives the optical member based on the difference between the target position and the position of the optical member, and the optical member at the target position Control means for controlling the drive means so as to drive toward the target, and the control means has a speed of the optical member higher than the target speed when the optical member is stopped at the target position at least. The drive means is controlled so that the followability of the speed of the optical member with respect to the target speed is lower when the speed is higher than when the speed is higher.

  According to the present invention, in the lens device that drives the optical member by the drive unit, the drive control that enables the optical member to be driven to the target position with high accuracy without providing the initialization operation and the restriction of the drive unit. It is possible to provide a lens apparatus provided with the means.

Block diagram of the lens apparatus of the present invention Flow chart of target position setting in embodiment 1 Flowchart of one driving cycle in the first embodiment Flowchart of output value calculation control in Embodiment 1 Flowchart for applying a control gain to a correction amount according to the first embodiment. Relationship between ideal position and drive speed when target speed is faster than current speed Relationship between ideal position and drive speed when target speed is slower than current speed Relationship between position and drive speed when there is disturbance Flowchart of one drive cycle in the second embodiment Flowchart of output value calculation in first means in embodiment 2 Flowchart of calculating output value in second means in embodiment 2 Flowchart of output value calculation in third means in embodiment 3 Flowchart of one drive cycle in the fourth embodiment Flowchart of one drive cycle in the fifth embodiment Flowchart of drive determination in embodiment 5

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The lens apparatus according to the first embodiment of the present invention will be described below with reference to FIGS.
FIG. 1 is a block diagram illustrating an embodiment of the present invention, which is an example in which drive control of an optical member of a lens apparatus is configured.

  The input device 10 is an imaging device or a controller, and is connected to the lens device 20 and transmits a target position for driving the optical member 21. The lens device 20 includes an optical member 21, a drive unit (drive unit) 22, a position detection unit (position detection unit) 23, a calculation unit (speed derivation unit) 24, a communication unit 25, and a storage unit 26. In this embodiment, the optical member 21 is a focus lens that adjusts the focal position. The optical member 21 is connected to the drive unit 22 and the position detection unit 23. With this configuration, the drive unit 22 can drive the optical member 21, and the position detection unit 23 can detect the current position of the optical member 21. The drive unit 22 is an actuator such as a motor.

  The calculation unit 24 is a CPU of the lens device 20. The calculation unit 24 is connected to the communication unit 25 and the storage unit 26. With this configuration, the calculation unit (target position deriving unit) 24 can receive the drive command for the input device 10 from the communication unit 25 and can derive the drive target position of the optical member 21. The derived target position is stored in the storage unit 26. The calculation unit 24 is connected to the drive unit 22 and the position detection unit 23. With this configuration, the calculation unit 24 calculates an output value to the drive unit 22 based on the target position stored in the storage unit 26 and the current position of the optical member 21 transmitted from the position detection unit 23, It is possible to transmit to the drive unit 22. The output value calculation process is performed every fixed drive cycle in which the drive unit 22 can control the optical member 21 with high responsiveness. Furthermore, the calculating part 24 preserve | saves an output value to the preservation | save part 26 for every drive period. The output value stored in the previous drive cycle is overwritten, and the latest output value remains in the storage unit 26.

  In this embodiment, the communication unit 25 is a communication means having an electrical contact. The storage unit 26 is a memory in which a target position and an output value to the drive unit 22 are stored.

  The lens device 20 is connected to a camera device 30 including an imaging element (not shown) that receives a subject image formed by the lens device, thereby constituting an imaging device.

  Next, setting of the target position performed by the calculation unit 24 will be described using a flowchart. FIG. 2 is a flowchart for setting the target position performed by the calculation unit 24 in the first embodiment. Setting of the target position is started when a drive command is transmitted from the input device 10.

In S <b> 200, the calculation unit 24 receives the drive command transmitted from the input device 10 via the communication unit 25. When the reception is completed, the process proceeds to S201. The drive command will be described later.
In S201, the calculation unit (target position deriving unit) 24 calculates (derived) a target position for driving the optical member 21 based on the drive command. When the calculation of the target position ends, the process proceeds to S202.
In S202, the calculation unit 24 stores the target position calculated in S201 in the storage unit 26. When the storage of the target position is completed, the setting of the target position ends.

  As described above, the calculation unit 24 can set a target position for driving the optical member 21 when receiving a drive command from the input device 10. There are drive commands that specify a relative position from the current position and those that specify an absolute position, but there is no particular limitation. Further, the calculation method of the target position in S201 is not particularly limited.

  Next, the calculation process of the output value to the drive part 22 for every fixed drive period which the calculating part 24 performs is demonstrated using a flowchart. FIG. 3 is a flowchart of one driving cycle performed by the calculation unit 24 in the first embodiment.

In S301, the calculation unit 24 calculates an output value to the drive unit 22, and proceeds to S302. The method for calculating the output value will be described in detail later.
In S302, the calculation unit 24 stores the output value calculated in S303 in the storage unit 26, and proceeds to S303.
In S303, the calculation unit 24 transmits the output value calculated in S301 to the drive unit 22, and ends the process.

  As described above, the calculation unit 24 calculates an output value to the drive unit 22 for each fixed drive cycle. The drive unit 22 can be driven based on the transmitted output value. Here, the output value stored in the storage unit 26 is only the output value of the latest drive cycle, and the output value of the previous drive cycle is overwritten by the output value of the latest drive cycle.

  Next, the calculation method of the output value to the drive part 22 which the calculating part 24 performs in S301 of FIG. 3 is demonstrated using a flowchart. FIG. 4 is a flowchart of a subroutine for calculating an output value to the drive unit 22 performed by the calculation unit 24.

When the process proceeds to S301 in FIG. 3 in S400, the process is started, and the process proceeds to S401.
In S401, the calculation unit 24 calculates the difference between the target position stored in the storage unit 26 in S202 of FIG. 2 and the current position of the optical member 21 detected by the position detection unit 23. When the calculation is completed, the process proceeds to S402.
In S402, the calculation unit (speed deriving unit) 24 calculates a target speed based on the difference between the target position calculated in S401 and the current position. The target speed will be described later. When the calculation of the target speed is finished, the process proceeds to S403.
In S403, the calculation unit 24 calculates the difference between the target speed calculated in S402 and the current speed of the optical member. When the calculation of the difference is completed, the process proceeds to S404.
In S404, the calculation unit 24 calculates a correction amount for the output value currently output based on the difference calculated in S402. When the calculation of the correction amount is finished, the process proceeds to S405. The calculation of the correction amount will be described later.
In S <b> 405, the calculation unit 24 checks whether the output value is already stored in the storage unit 26. If not saved, the process proceeds to S406, and if saved, the process proceeds to S407.
In S <b> 406, the calculation unit 24 calculates an output value to the drive unit 22 based on the target position stored in the storage unit 26 and the current position of the optical member 21 transmitted from the position detection unit 23, and the storage unit 26. Save to When the process proceeds to S406, the subroutine for calculating the output value to the drive unit 22 is ended here.
In S407, the calculation unit 24 calculates an output value to the drive unit 22 based on the correction amount calculated in S404 and the output value stored in the storage unit 26. The calculation method will be described later. Here, the subroutine for calculating the output value to the drive unit 22 is terminated.

  As described above, the calculation unit 24 calculates the target speed, operates the drive unit output value of the previous drive cycle, and calculates the output value to the drive unit 22, so that the optical member 21 can be accurately reached to the target position. It becomes possible to drive.

  Here, the target speed calculated in S402 will be described. The target speed calculated in S402 is set so that the target speed is 0 when the difference between the target position and the current position is 0, and increases as the distance from the target position increases. That is, when the current position is not the target position, a target speed corresponding to the difference between the target position and the current position is set, and the output value to the drive unit 22 is controlled so as to be the target speed. Therefore, since the target speed does not become zero until the optical member 21 is driven to the target position, the optical member 21 can be driven to the target position without stopping by manipulating the output value so as to become the target speed. It is.

Next, the correction amount calculated in S404 will be described. The correction amount C calculated in S404 can be obtained by the following equation (1), where the target speed is V1, the current speed is V2, and the control gain is G1.
C = (V1-V2) × G1 (1)
That is, the correction amount C is derived as a value proportional to the difference between the target speed V1 and the current speed V2 (assumed to be ΔV). When the target speed V1 is faster (larger) than the current speed V2, the correction amount C is a positive value (correction that increases the current output value). On the other hand, when the target speed V1 is slower (smaller) than the current speed V2, the correction amount C is a negative value (correction that decreases the current output value). When the correction amount C is positive, the speed of the optical member 21 is increased. When the correction amount C is negative, the speed of the optical member 21 is decreased.

Next, an output value calculation method will be described. In S407, assuming that the drive unit output value in the nth cycle is O (n) and the correction amount in the nth cycle is C (n), the relationship of the following equation (2) is established.
O (n) = O (n−1) + C (n) (2)
According to the equation (2), it is possible to drive the optical member 21 while correcting the current speed so as to approach the target speed by correcting and updating the output value for each period by the correction amount C (n).

In this control, the output value of the previous drive cycle is used, but the output value is not stored in the storage unit 26 in the first drive cycle. Therefore, by performing calculation and storage in S406, it is possible to quickly follow the target speed. In this embodiment, when the output value is O, the target position is P1, the current position is P2, and the control gain is G2, the output value is calculated by the following equation (3).
O = (P1-P2) × G2 (3)
That is, the output value O is derived as a value proportional to the difference between the target position P1 and the current position P2. In this embodiment, the output value O is calculated in this way, but it may be obtained by other methods.

  Next, the calculation of the correction amount will be described in detail in S404. FIG. 5 is a flowchart of a subroutine for calculating the correction amount performed by the calculation unit 24 in S404 of FIG.

In S501, the calculation unit 24 calculates a correction amount for the current speed necessary to bring the current speed closer to the target speed based on the difference between the target speed and the current speed. The final correction amount is calculated by multiplying the correction amount calculated here by the control gain. When the calculation is completed, the process proceeds to S502.
In S502, the calculation unit 24 determines whether the current speed is faster than the target speed based on the difference calculated in S501. If it is fast, the process proceeds to S504. In other cases (same speed or slow), the process proceeds to S503.
In S503, the calculation unit 24 multiplies the correction amount calculated in S501 by the first control gain corresponding to the speed difference calculated in S501. When the first control gain is applied, the correction amount calculation ends.
In S504, the computing unit 24 multiplies the correction amount calculated in S501 by a second control gain corresponding to the speed difference calculated in S501. When the second control gain is applied, the correction amount calculation ends.
In S503 and S504, the current speed and the target speed are compared, and different control gains are applied based on the magnitude relationship between the current speed and the target speed. That is, the current speed is controlled so as to follow the target speed with different followability. By doing so, it is possible to improve stopping accuracy and responsiveness.

  As described above, the calculation unit 24 enables control to drive the target position with high accuracy without causing overshoot or hunting by changing the control gain. By using the method of the present invention, the effects of the present invention can be enjoyed, but it is only necessary that the method be implemented at least near the target position. Furthermore, the control method of the present invention may be applied when the target position of the present invention or a predetermined range from the target position is reached and stopped. The predetermined range is, for example, a range corresponding to a depth of focus where a focus shift is not recognized even if the position of the focus lens is not the target position when the optical member is a focus lens. In this case, the predetermined range is determined based on the allowable confusion circle diameter of the imaging device and the F value of the lens.

  Here, the effect of the output value calculation method in FIG. 4 will be described. FIG. 6 and FIG. 7 show the relationship between the ideal target speed and the current speed when driving to the target position by performing this control. FIG. 6 shows a case where the target speed is faster than the current speed at the beginning of driving. FIG. 7 shows a case where the target speed is slower than the current speed at the beginning of driving. Under ideal conditions, the current speed follows the target speed at a speed slightly faster than the target speed.

  FIG. 8 shows the relationship between the target speed and the current speed when driving is performed under this control under the condition that the speed is lowered due to the influence of the torque and the attitude difference. When the current speed falls below the target speed due to speed reduction due to disturbance, the calculation unit 24 corrects the output value to be immediately increased. Therefore, the current speed immediately exceeds the target speed and follows at a speed slightly higher than the target speed.

  Further, as shown in FIGS. 6 and 7, the target speed is 0 at the target position, and the output value is manipulated so that the current speed is 0 at the target position. Therefore, the current speed becomes 0 at the target position, and it is possible to stop.

Next, the effect of switching the control gain in FIG. 5 will be described.
If the correction amount is small when the current speed is faster than the target speed and the correction amount is a negative value, it is difficult to decrease the output value to decrease the current speed. If feedback control is performed with a small correction amount as it is, the current speed cannot be zero at the point where the target speed becomes zero (target position), and the target position is exceeded, causing overshoot. Further, if the control gain is increased both when the current speed is faster than the target speed and when the current speed is slower than the target speed, it becomes difficult to finely control the speed near the position where the target speed becomes zero, which causes hunting.

  Therefore, in the drive control of the present invention, when the current speed is faster than the target speed, a second control gain that is larger than the first control gain is applied, and the correction amount is more negative than when the first control gain is applied. Increase in the direction (make the follow-up performance to the target speed higher) and decrease the output value. Thereby, the stop accuracy can be improved. That is, it is difficult to cause overshoot, the occurrence of hunting is prevented, and the target position can be stopped with high accuracy. In the drive control of the present invention, when the current speed is slower than the target speed, a first control gain smaller than the second control gain is applied so that the followability to the target speed is lowered, and the current speed is reduced. The target speed is not easily exceeded. In this embodiment, the second control gain is twice as large as the first control gain.

  In this embodiment, the optical member 21 is a focus lens. However, the present invention is not limited to this, and the optical member 21 may be applied to a zoom lens that adjusts the focal length or to drive control of a diaphragm blade that adjusts the amount of light. The communication unit 25 may use a wireless communication unit that does not have an electrical contact.

  In the present embodiment, the second control gain is set to be twice the first control gain. However, the present invention is not limited to this, and the control gain can be set freely according to the position and speed of the optical member 21. Good. It is preferable to set the second control gain in a range of not less than 2 times and not more than 32 times the first control gain. When set to less than 2 times, the difference between the first control gain and the second control gain is too small to obtain the effect of the present invention. On the other hand, if it exceeds 32 times, the difference in control gain with the target speed as a boundary is too large, which causes pulsation and hinders the stability of drive control, which is not preferable.

  In a drive region where the current position of the optical member 21 is away from the target position by a threshold value (second threshold value) or more and drive control in consideration of stopping accuracy at the target position and prevention of hunting control in the vicinity of the target position is not required. In some cases, the first control gain may be set larger than the second control gain. As a result, when the current speed is smaller than the target speed, it is possible to drive with good responsiveness by increasing the output value by increasing the correction amount in the positive direction. On the other hand, when the current speed is larger than the target speed, a negative correction amount is gently given toward the target speed without giving a correction amount for sudden deceleration.

  Thus, the lens device of the present invention can drive the optical member to the target position without hunting with high accuracy.

  The lens apparatus according to the second embodiment of the present invention will be described below with reference to FIGS.

1 is the same as the block diagram of the first embodiment shown in FIG. 1 because the configuration of the imaging apparatus including the lens device of the present embodiment is not described here.
Further, the outline of the target position setting process performed by the calculation unit 24 is the same as the process in the first embodiment described with reference to the flowchart of FIG. The calculation unit 24 can set a target position for driving the optical member 21 when a drive command is received from the input device 10. There are drive commands that specify a relative position from the current position and those that specify an absolute position, but there is no particular limitation. Moreover, the calculation method of the target position in S201 is not specifically limited.

  Next, the calculation process of the output value to the drive part 22 for every fixed drive period which the calculating part 24 performs is demonstrated using a flowchart. FIG. 9 is a flowchart of one drive cycle performed by the calculation unit 24 in the second embodiment.

In step S901, the calculation unit 24 (drive detection unit) determines whether or not the optical member 21 is moving. A method for determining whether or not the optical member 21 is moving will be described in detail later. If the optical member 21 has moved, the process proceeds to S903, and if not, the process proceeds to S902.
In S902, the calculation unit 24 calculates an output value to the drive unit 22 by the first means. The calculation method of the output value of the first means will be described in detail later. When the calculation of the output value is finished, the process proceeds to S302.
In S903, the calculation unit 24 calculates an output value to the drive unit 22 by the second means. The method for calculating the output value of the second means will be described in detail later. When the calculation of the output value is finished, the process proceeds to S302.
In S302, the calculation unit 24 stores the output value calculated in S902 or S903 in the storage unit 26. When the output value is stored, the process proceeds to S303.
In S303, the calculation unit 24 transmits the output value calculated in S902 or S903 to the drive unit 22, and ends the process.

  As described above, the calculation unit 24 calculates an output value to the drive unit 22 for each fixed drive cycle. The drive unit 22 can be driven based on the transmitted output value. Here, the output value stored in the storage unit 26 is only the output value of the latest drive cycle, and the output value of the previous drive cycle is overwritten with the output value of the latest drive cycle.

  Here, determination of the start of driving of the optical member 21 in S901 will be described. When determining whether or not the optical member 21 is moving, the current speed (drive speed) of the optical member 21 may be used. Alternatively, the movement may be determined by sampling the position of the optical member 21 at regular intervals and taking the difference. Further, the movement of the optical member 21 may be determined by detecting the power supply current of the drive unit 22. Further, the start of movement of the optical member 21 may be determined by measuring the elapsed time after receiving the drive command in the stopped state. Thus, the means for determining the start of driving of the optical member 21 and the threshold value do not matter.

  At this time, it is necessary to set a threshold value for determining whether or not the optical member 21 is moving. The threshold value may be set based on the current F value of the lens device 20. Alternatively, the permissible circle of confusion of the camera device 30 may be acquired via the communication unit 25 and determined based on the acquired permissible circle of confusion. Further, it may be determined based on the current focal length of the lens device 20.

  Here, it is possible not to switch the calculation of the output value by setting each threshold value to a value before starting movement or a value that cannot be reached even if moving. By doing so, it is possible to always use the output value of the first means or the output value of the second means before and after the start of movement.

  By setting a threshold value for starting movement, it is possible to make an appropriate determination for starting movement in various situations. For example, the depth of field changes depending on the F value of the lens device, the allowable circle of confusion of the imaging device, and the focal length. At this time, when the focus lens is moved, especially when the depth of field is shallow, it is possible to determine the movement start even with a small movement amount by reducing the threshold value. In addition, when the depth of field is deep, by increasing the movement start threshold value, it is possible to set a threshold value that does not switch the process and does not complicate the output value calculation process.

  Next, the calculation method of the output value of the first means to the drive unit 22 performed by the calculation unit 24 in S902 of FIG. 9 will be described using a flowchart. FIG. 10 is a flowchart showing a subroutine for calculating an output value to the drive unit 22 performed by the calculation unit 24 in the first means.

The process starts from S1000 and proceeds to S1001.
In S <b> 1001, the calculation unit 24 calculates a difference between the target position stored in the storage unit 26 and the current position of the optical member 21 detected by the position detection unit 23. When the calculation is completed, the process proceeds to S1002.
In S1002, the calculation unit 24 calculates an output value based on the difference calculated in S1001. Here, the calculation of the output value to the drive unit 22 of the first means is finished.

Here, the output value calculated in S1002 will be described. When the output value is O, the target position is P1, the current position is P2, and the control gain is G1, the output value is calculated by the following equation (4).
O = (P1-P2) × G1 (4)
That is, the output value O is derived as a value proportional to the difference between the target position P1 and the current position P2.

  As described above, the output value determined by the target position and the current position of the optical member 21 is obtained until the optical member 21 starts moving.

  Next, the calculation method of the output value of the second means to the drive unit 22 performed by the calculation unit 24 in S903 of FIG. 9 will be described using a flowchart. FIG. 11 is a flowchart for calculating an output value to the drive unit 22 performed by the calculation unit 24.

The process starts in S1100 and proceeds to S1101.
In S1101, the calculation unit 24 calculates a difference between the target position stored in the storage unit 26 in S202 of FIG. 2 and the current position of the optical member 21 detected by the position detection unit 23. When the calculation is completed, the process proceeds to S1102.
In S1102, the calculation unit 24 calculates a target speed from the difference between the target position calculated in S1101 and the current position. The target speed will be described later. When the calculation of the target speed is finished, the process proceeds to S1103.
In S1103, the calculation unit 24 calculates the difference between the target speed calculated in S1102 and the current speed of the optical member. When the calculation of the difference is finished, the process proceeds to S1104.
In S1104, the calculation unit 24 calculates a correction amount of the output value based on the difference calculated in S1103. When the calculation of the correction amount is finished, the process proceeds to S1105. The calculation of the correction amount will be described later.
In S <b> 1105, the calculation unit 24 calculates a drive unit output value from the correction amount calculated in S <b> 1104 and the output value stored in the storage unit 26. The calculation method will be described later. Here, the calculation of the output value to the drive unit 22 of the second means is finished.

  Here, the target speed will be described. The target speed calculated in S1102 increases as the distance from the target position increases. When the difference between the target position and the current position is zero, the target speed is zero. Therefore, since the target speed does not become zero until the optical member 21 moves to the target position, the optical member 21 can be moved to the target position without stopping by manipulating the output value so as to become the target speed. Is possible.

Next, calculation of the correction amount will be described. The correction amount C calculated in S1104 can be obtained by the following equation (5), where the target speed is V1, the current speed is V2, and the control gain is G2.
C = (V1−V2) × G2 (5)
That is, the correction amount C is derived as a value proportional to the difference between the target speed V1 and the current speed V2 (assumed to be ΔV). When the target speed V1 is faster (larger) than the current speed V2, the correction amount C is a positive value, and when the target speed V1 is slower (smaller) than the current speed V2, it is a negative value. When the correction amount C is positive, the speed of the optical member 21 is increased. When the correction amount C is negative, the speed of the optical member 21 is decreased.

Next, an output value calculation method will be described. In S1105, assuming that the drive unit output value in the nth cycle is O (n) and the correction amount in the nth cycle is C (n), the relationship of the following equation (6) is established.
O (n) = O (n−1) + C (n) (6)
The optical member 21 can be driven at the target speed by correcting the output value by a correction amount and updating it for each period according to the equation (6).

  Here, in FIG. 9, the effect of switching the output value calculation means before and after the start of the movement of the optical member 21 will be described. The optical member 21 cannot move immediately after receiving the drive command due to the calculation time, operating torque, and backlash of the control unit. Therefore, if the output value is calculated by the second means before the movement starts, the current speed is 0, so that an excessive correction amount is fed back and the output value becomes too large. In particular, when performing control to move to the target position with a small amount of movement when it is in the vicinity of the target position, if the output value is too large, it accelerates rapidly, and a small target speed because it is close to the target position can be easily achieved. It can easily occur that the target position is exceeded without being decelerated. On the other hand, in the first process performed during the stop, an output value determined by the current position and the target position of the optical member 21 is calculated. Therefore, in the first means, when the optical member 21 is stopped, the output value becomes a constant value determined by the difference between the current position and the target position, and the movement can be started without applying extra feedback. . Due to the difference in the calculation method, the driving is based on the calculation of the output value by the first means until the driving (the optical member starts moving) in FIG. 9, and the second means after the driving (starting the movement). High-precision driving is possible by performing driving based on the calculation of the output value.

  In this embodiment, the optical member 21 is a focus lens. However, the present invention is not limited to this, and the optical member 21 may be applied to a zoom lens that adjusts the focal length or to drive control of a diaphragm blade that adjusts the amount of light. The communication unit 25 may use a wireless communication unit that does not have an electrical contact.

  As described above, in the present embodiment, the drive control means that enables the optical member to be moved to the target position with high accuracy without setting the initialization operation and the drive unit under the ideal control system conditions. It is possible to provide a lens device provided.

  According to the present invention, in a lens apparatus that moves an optical member by a driving unit, the optical member is not subject to hunting without causing an overshoot at a target position without providing an initialization operation or a restriction on the driving unit. It is possible to provide a lens apparatus including a drive control unit that can be moved.

A lens apparatus according to a third embodiment of the present invention will be described. In the present embodiment, the basic configuration is the same as that of the second embodiment, but the output value calculation process before the start of movement is different. Hereinafter, differences from the second embodiment will be described.
In the present embodiment, in step S901 in FIG. 9, after the branch when the optical member is not moved (to the No side), the driving unit output value is calculated by the third means instead of the first means. Different from Example 2.

  The calculation method of the output value of the 3rd means to the drive part 22 which the calculating part 24 performs to FIG. 12 is demonstrated using a flowchart. The basic flow is the same as that in FIG. 11, and the same symbols are attached to the same flow and the description is omitted.

Steps S1100 to S1104 are the same as the calculation of the drive unit output value by the second means shown in FIG.
In the present embodiment, in S1201, a control gain for reducing the correction amount calculated in S1104 is applied.
Since S1105 is the same as that of FIG.
As described above, the output value can be gradually increased by reducing the correction amount before the start of driving.

  Here, the effect of the present embodiment will be described. The movement of the optical member cannot be performed immediately after receiving the drive command due to the calculation time, operating torque, and backlash. If the output value is calculated while the correction amount is too large before the movement is started, the current speed is 0 before the movement is started, so that an extra correction amount is fed back and the output value becomes too large. In particular, when moving a minute amount, if the output value is too large, the target position is exceeded. Therefore, the third means applies a control gain different from that at the time of movement until the movement is started, thereby reducing the correction amount and gradually increasing the output value. By doing so, the output value does not exceed the target position even with a small amount of movement, and it is possible to perform accurate movement to the target position.

  As described above, in this embodiment, it is possible to provide a lens apparatus including a high-accuracy drive control unit by setting the correction amount to be small before the start of movement.

  According to the present invention, in a lens device that moves an optical member by a driving unit, it is possible to move the optical member with high accuracy without hunting to a target position without providing any initialization operation or restrictions on the driving unit. It is possible to provide a lens apparatus provided with the drive control means.

  A lens device according to a fourth embodiment of the present invention will be described. In this embodiment, the basic configuration is the same as that of the second embodiment. However, even when the optical member is stopped, the first means and the second means are switched depending on the elapsed time of the stop. Different. Hereinafter, differences from the second embodiment will be described.

  The calculation process of the output value to the drive part 22 for every fixed drive period in Example 3 which the calculating part 24 performs in FIG. 13 is demonstrated using a flowchart. The basic flow is the same as that in FIG. 9, and the same symbols are attached to the same flow, and the description is omitted.

In S901, the calculation unit 24 determines whether the optical member 21 is moving. If the optical member 21 has moved, the process proceeds to S903, and if not, the process proceeds to S1301.
In S1301, the calculation unit 24 measures (acquires) an elapsed time after the communication unit 25 receives the drive command. If the elapsed time is equal to or greater than the threshold, the process proceeds to S903, and if it is less than the threshold, the process proceeds to S902.
S302 and S303 are the same as those in FIG.

  With the above processing, the calculation unit 24 does not necessarily calculate the output value by the first means even if the optical member is stopped, and continues to receive the drive command after receiving the drive command. It is possible to change the calculation method of the output value so that the second means calculates according to the elapsed time.

  The effect of the present embodiment will be described. The lens apparatus according to the second exemplary embodiment calculates the output value uniquely determined by the position difference by the first means until the movement is detected after receiving the driving command. However, when the target position is very close to the current position of the optical member 21, there is a situation in which driving cannot be performed with the output value calculated by the first means due to backlash and torque. Therefore, in the drive control of this embodiment, when it is confirmed that no movement has occurred after a predetermined time has elapsed since the drive command was received, the process proceeds to the output value calculation method of the second means. By doing so, the output value can be fed back according to the speed, so that driving is possible.

  In this embodiment, the elapsed time is measured after the communication unit 25 receives the drive command. However, the present invention is not limited to this, and the start of the elapsed time may be set freely. In the present embodiment, the threshold value of the elapsed time for changing the process is not limited, but the driving torque and the backlash amount may be referred to. In this way, it is possible to set an optimum elapsed time for each lens.

  As described above, in this embodiment, it is possible to provide a lens device including a drive control unit that enables the optical member to be moved with high accuracy by changing the output value calculation unit according to the elapsed time. is there.

  According to the present invention, in a lens device that moves an optical member by a driving unit, it is possible to move the optical member with high accuracy without hunting to a target position without providing any initialization operation or restrictions on the driving unit. It is possible to provide a lens apparatus provided with the drive control means.

  A lens device according to a fifth embodiment of the present invention will be described. In the present embodiment, the basic configuration is the same as that of the fourth embodiment, but the movement detection method is different. Hereinafter, differences from the fourth embodiment will be described.

  The calculation process of the output value to the drive part 22 for every fixed drive period in Example 5 which the calculating part 24 performs in FIG. 14 is demonstrated using a flowchart. The basic flow is the same as that in FIG. 13, and the same symbols are attached to the same flow and the description is omitted.

In S1401, the calculation unit 24 determines whether the optical member 21 is moving. When the determination is finished, the process proceeds to S1402. The determination method will be described in detail later.
In S1402, the calculation unit 24 determines whether it is determined in S1401 that the optical member is moving. If it is determined that the object is moving, the process proceeds to step S903. If it is determined that the object is not moved, the process proceeds to step S1301.
Steps S1301 to S303 are the same as those in FIGS.
As described above, the calculation unit 24 can finely determine drive detection.

  Here, the movement determination of the optical member 21 in S1401 of FIG. 14 will be described using a flowchart. FIG. 15 is a flowchart of the movement determination of the optical member 21 performed by the calculation unit 24.

In S1501, the calculation unit 24 determines whether or not the optical member 21 is moving. If it has moved, the process proceeds to S1502. If it has not moved, the process proceeds to S1505. A method similar to that of the second embodiment may be used for determining whether or not the user is moving.
In S1502, the computing unit 24 detects the direction in which the optical member 21 is moving. If the moving direction is detected, the process proceeds to S1503. The method of detecting the moving direction will be described in detail later.
In S1503, the calculation unit 24 determines whether the movement direction of the optical member 21 detected in S1502 is the direction of the target position with respect to the current position. If the movement direction is the target position direction, the process proceeds to S1504. If the movement direction is the direction opposite to the target position, the process proceeds to S1505.
In S1504, the calculation unit 24 determines whether the difference between the current position of the optical member 21 and the target position is equal to or less than a threshold value (first threshold value). If it is equal to or smaller than the threshold, the process proceeds to S1505. If it is greater than the threshold, the process proceeds to S1506.
In S1505, the calculation unit 24 determines that the optical member 21 has not moved, and ends the determination process for determining whether or not the optical member 21 has moved.
In S1506, the calculation unit 24 determines that the optical member 21 is moving, and ends the determination process of whether it is moving.

  As described above, the calculation unit 24 can set in detail the condition as to whether or not the optical member 21 is moving.

  Here, the method of detecting the moving direction in S1502 will be described. In this embodiment, the movement direction is detected by sampling the position of the optical member 21 at regular intervals and taking the difference. In this way, it is possible to detect the moving direction by checking whether the position difference is positive or negative.

  Next, the effect of the present embodiment will be described. In the lens apparatus according to the fourth exemplary embodiment, the process is switched by determining whether or not the lens apparatus is moving. However, since the moving direction is not considered, when the target position is reset while the optical member 21 is moving and the lens apparatus receives a new drive command, the optical member 21 is moved in S901 in FIG. It is determined that At this time, if a new target position is set at a position very close to the direction opposite to the moving direction, if the output value is calculated by the second means, extra feedback will be applied before the reversing operation is performed. Therefore, it is difficult to accurately calculate the output value. Further, since the second means gradually changes the output value, it takes time until the inversion. Therefore, in S1503, it is determined that the optical member 21 has not moved until the movement direction becomes the target position direction, and the output value is calculated by the first means in S902 of FIG. By doing so, it is possible to accurately move to the target position without applying extra feedback even when the driving direction changes. Further, since the first means calculates the output value based on the position, the output value can be reversed immediately after the target position is reversed.

  Further, even if the movement direction is the same as the target position, if the new target position is set very close to the optical member 21, it takes time to lower the output value in the second means, and the target position is passed. A situation occurs. Therefore, when the new target position is set very close to the optical member 21, it is determined that the optical member 21 has not moved (S1504), and the output value is calculated by the first means in S902 of FIG. . By doing so, it is possible to quickly set the output value to an appropriate value, and it is possible to accurately move to the target position.

  In the present embodiment, the position of the optical member 21 is used as the method of detecting the moving direction, but the determination may be made by giving polarity to the speed.

  As described above, in the present embodiment, the drive control means that enables the optical member to be moved to the target position with high accuracy without setting the initialization operation and the drive unit under the ideal control system conditions. It is possible to provide a lens device provided.

  According to the present invention, in the lens device that moves the optical member by the drive unit, the drive control means that can efficiently move to the target position with high accuracy without providing the initialization operation and the restriction of the drive unit. It is possible to provide a lens device provided. In addition, an imaging apparatus that enjoys the effects of the present invention can be realized by an imaging apparatus that includes the lens apparatus described above and a camera apparatus that includes an imaging element that receives a subject image formed by the lens apparatus.

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

20: Lens device 21: Optical member 22: Drive unit (drive means)
23: Position detection unit (position detection means)
24: arithmetic unit (control means, speed deriving means, target position deriving means)

Claims (12)

An optical member; a driving means for driving the optical member; a detecting means for detecting a position of the optical member; a target position deriving means for setting a target position for driving the optical member; the target position and the optical member A speed deriving unit for deriving a target speed at which the driving unit drives the optical member, and a control unit for controlling the driving unit to drive the optical member toward the target position. And having
When the control means stops at least the optical member to the target position, the followability of the speed of the optical member with respect to the target speed is slower when the speed of the optical member is higher than the target speed. Controlling the driving of the driving means so as to be low,
A lens device. Drive detection means for detecting whether the optical member is moving;
The control means controls the drive of the drive means so that the speed of the optical member becomes the target speed when the drive detection means detects that the optical member is moving, and the drive When the detection means detects that the optical member is not moved, the drive of the drive means is controlled based on the position of the optical member.
The lens device according to claim 1.   The lens apparatus according to claim 2, wherein the drive detection unit determines whether or not the optical member is moving based on a power source current of the drive unit.   The lens apparatus according to claim 2, wherein the drive detection unit determines whether or not the optical member is moving based on a driving speed of the optical member.   The drive detection means determines that the optical member is moving when the control means continues to output the drive command for a predetermined time after outputting the drive command to the drive means. The lens device according to claim 2.   The said drive detection means determines the threshold value which judges whether the said optical member is moving based on F value of a lens apparatus, The any one of Claim 2 thru | or 5 characterized by the above-mentioned. Lens device.   The said drive detection means determines the threshold value which judges whether the said optical member is moving based on the focal distance of the said lens apparatus, The any one of Claim 2 thru | or 5 characterized by the above-mentioned. Lens device.   6. The drive detection unit according to claim 2, wherein the drive detection unit acquires an allowable circle of confusion and determines a threshold value for determining whether or not the optical member is moving based on the allowable circle of confusion. 2. The lens device according to item 1.   The drive detection means does not move until the movement of the optical member in the movement direction stops when the target position is reset to a position opposite to the movement direction during movement of the optical member. The lens device according to claim 2, wherein the lens device is determined.   When the target position is reset in the same direction as the movement direction of the optical member during the movement of the optical member, the control means determines a difference between the reset target position and the position of the optical member. When it is less than a threshold value of 1, the drive of the drive means is controlled with an output value based on the position of the optical member, and when the value is equal to or greater than the first threshold value, the speed of the optical member becomes the target speed. The lens apparatus according to claim 2, wherein driving of the driving unit is controlled.   When the position of the optical member is separated from the target position by a second threshold or more, the control means can follow the target speed more quickly than when the speed of the optical member is slower than the target speed. The lens device according to any one of claims 1 to 10, wherein control is performed to increase the image quality.   An imaging apparatus comprising: the lens apparatus according to claim 1; and a camera apparatus including an imaging element that receives a subject image formed by the lens apparatus.

Images