JP2009008984A - Lens drive device, lens drive method, focusing device and imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens drive device capable of moving a lens to a proper position regardless of the present position of the lens. <P>SOLUTION: The lens drive device 1 includes a lens drive control part 14 repeating drive for every predetermined second moving amount D2 after performing initial drive for driving the lens 21 from the present lens position Pn by a first moving amount D1 when moving the lens 21 in the optical axis direction of the lens 21. The lens drive control part sets the first moving amount D1 in accordance with the present lens position. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a lens driving device, a driving method, a lens focus adjustment device, and an imaging device used in an imaging device or the like.

As a method for detecting the focus adjustment state in the optical system of the imaging apparatus, a contrast detection method is known. In this contrast detection method, the lens is initially driven by a predetermined amount of movement in the direction of the optical axis from the current position, and intermittently driven by a predetermined amount from that position, and the contrast value of the image at each position is detected to detect the in-focus position. (For example, refer patent document 1).

By the way, an imaging device or the like is provided with a mechanical mechanism for moving the lens in the optical axis direction, and the lens position is controlled by a position detector such as an encoder to control driving of the lens. At this time, in order to prevent damage to the encoder or the like, normal electrical drive control may be performed within a range having a predetermined margin from both ends of each moving range of the lens mechanical mechanism.

However, if the lens is moved near the end of the moving range of the mechanical mechanism by manual operation or the like, there is a problem that proper initial driving cannot be performed.

JP 2004-109690 A

The problem to be solved by the present invention is to provide a lens driving device, a lens driving method, a focus adjusting device, and an imaging device capable of moving the lens to an appropriate position regardless of the current position of the lens.

  The present invention solves the above problems by the following means. In addition, although the code | symbol corresponding to drawing which shows embodiment of this invention is attached | subjected and demonstrated, this code | symbol is only for making an understanding of this invention easy, and is not the meaning which limits this invention.

[1] In the lens driving device according to the first aspect of the present invention, when the lens (21) is moved in the direction of the optical axis (2) of the lens, the lens is first moved from the current lens position (Pn). A lens driving device having control means (14) that repeats the driving for each predetermined second movement amount (D2) after performing the initial driving for driving the amount (D1), wherein the control means determines the current lens position. The first movement amount is set according to the above.

  As one form of the invention according to the first aspect, the second range (M1 to E1, M2 to E2) exceeds the first range (L2) in the optical axis direction in which the lens position can be controlled by the control means. And moving means (212 etc.) capable of moving the lens.

In the above invention, as one form of initial drive when the lens is located in the second range,
(I) A mode in which initial driving is performed with a movement amount obtained by adding a lens movement amount corresponding to the second range to the first movement amount instead of the first movement amount;
(Ii) a mode in which initial driving is performed with a movement amount corresponding to the second range instead of the first movement amount;
(Iii) A mode in which the initial driving is repeatedly performed in a direction in which the first range exists instead of the first movement amount by a predetermined unit driving amount can be given.

  Alternatively, (iv) instead of the initial driving, when the lens is located in the second range, the lens can be moved to a predetermined position in the first range.

  The first movement amount can be set based on the lens position and the driving direction for each second movement amount.

[2] A focus adjustment device according to a second aspect of the present invention is a focus detection unit that detects a focus adjustment state of a lens by detecting a focus evaluation value based on a contrast value of an image by the lens driving device and the lens. (12), wherein the focus detection unit obtains a focus evaluation value every time the lens is driven by the second movement amount after the initial drive.

[3] In the lens driving method according to the third aspect of the present invention, when the lens is moved in the optical axis direction of the lens, initial driving is performed to drive the first movement amount from the current lens position. This is a lens driving method that repeats driving for each predetermined second movement amount later, and the first movement amount is set according to the current lens position.

[4] The lens driving device of the present invention is preferable when applied to the imaging device (1).

  In the present invention, since the first movement amount is set according to the current lens position, the lens can be moved to an appropriate position regardless of the current position of the lens.

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

FIG. 1 is a block diagram illustrating an image pickup apparatus according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view illustrating a focus lens moving mechanism according to the embodiment of the present invention.

The imaging apparatus 1 of the present embodiment includes a camera body 10 and a lens barrel 20. The lens barrel 20 includes a focus lens 21 that can move along the optical axis 2, and the focus lens 21 that has an optical axis 2. A lens drive motor 22 that moves along the lens and a lens position detector 23 for detecting the position of the focus lens 21 are provided.

An example of a moving mechanism along the optical axis 2 of the focus lens 21 is shown in FIG. In this example, the focus lens 21 is fixed to a lens frame 211, the lens frame 211 is provided inside a cylindrical body called a cam ring 212, and the cam ring 212 is further fixed to a fixed cylinder 213 of the lens barrel 20. Is inserted so as to be rotatable. A cam follower 215 formed at one end of the lens frame 211 is inserted into the cam 216 formed in the cam ring 212 and the hole 217 of the fixed cylinder 213.

The cam 216 of the cam ring 212 is formed as a long hole having an inclination angle that causes the lens frame 211 to move along the optical axis 2 when the cam ring 212 is rotated, while the hole 217 of the fixed cylinder 213 is It is formed by a long hole along the optical axis 2.

The cam ring 212 is rotated in any circumferential direction by the mechanism of the lens frame 211, the cam ring 212, and the fixed cylinder 213, the cam follower 215 of the lens frame 211, the cam 216 of the cam ring 212, and the hole 217 of the fixed cylinder 213. Then, the focus lens 21 fixed to the lens frame 211 moves along the optical axis 2 to either the subject side or the camera body side. Further, when the cam ring 212 is rotated in the reverse direction, the focus lens 21 moves along the optical axis 2 to either the subject side or the camera body side.

The lens barrel 20 is provided with a lens group other than the focus lens 21. Here, the embodiment will be described by taking the focus lens 21 as an example.

As described above, the focus lens 21 fixed to the lens frame 211 is moved in the optical axis direction by rotating the cam ring 212, and a lens driving motor 22 (actuator) as a driving source is provided in the lens barrel 20. It has been. A focus drive pin 221 that is movable along the circumferential direction of the lens barrel 20 is connected to the drive shaft of the lens drive motor 22, and the tip of the focus drive pin 221 passes through the hole 222 of the fixed barrel 213. It is fixed to the cam ring 212.

When the drive shaft of the lens drive motor 22 is rotationally driven in any circumferential direction, the focus drive pin 221 is also moved in any direction along the circumferential direction, whereby the cam ring 212 is moved in any circumferential direction. By rotating, the focus lens 21 fixed to the lens frame 211 moves in any direction of the optical axis 2. When the drive shaft of the lens drive motor 22 is rotationally driven in the reverse direction, the focus lens 21 moves in the reverse direction of the optical axis 2.

The position of the focus lens 21 is detected by an encoder which is a lens position detector 23. As described above, since the position of the focus lens 21 in the optical axis direction correlates with the rotation angle of the cam ring 212, for example, it is obtained by detecting the relative rotation angle of the cam ring 212 with respect to the fixed cylinder 213 of the lens barrel 20. be able to.

As the encoder 23 of this example, a flexible printed circuit board 231 provided along the circumferential direction on one of the cam ring 212 and the fixed cylinder 213 (the cam ring 212 in the example shown in FIG. 2), the cam ring 212 and the fixed cylinder 213. 2 (fixed cylinder 213 in the example shown in FIG. 2), and has a brush 232 that contacts the flexible printed circuit board 231 of the encoder, and by detecting an electrical output value depending on the contact position of the brush 232, An example of detecting the relative rotation angle of the cam ring 212 with respect to the fixed cylinder 213 can be given.

However, the specific configuration of the lens position detection unit 23 is not particularly limited, and the lens position detection unit 23 detects the absolute rotation angle of the cam ring 212 relative to the fixed cylinder 213, and the relative movement amount of the lens frame 211 in the optical axis direction. Or what detects an absolute position may be used.

The focus lens 21 can move in the optical axis direction from the end on the camera body side to the end on the subject side by the rotation of the cam ring 212 described above, and this movement is performed by the lens drive control unit of the camera body 10. 14 is controlled by a command from 14.

Here, in the imaging apparatus 1 of the present example, if the focus lens 21 is moved to the end on the camera body side or the end on the subject side, the encoder 23 or the like described above may be damaged. The control range of the focus lens 21 by the lens drive control unit 14 is set slightly smaller than the mechanically movable range.

FIG. 5 is a diagram showing a driving range of the focus lens according to the present embodiment. As shown in the figure, when the range in which the focus lens 21 can be mechanically moved by the cam ring 212 and the like is L1 from the position M1 on the camera body side to the position M2 on the subject side, the lens drive control unit 14 The range in which the focus lens 21 can be moved by a command to the lens drive motor 22 is set to L2 from the position E1 on the camera body side to the position E2 on the subject side.

Therefore, unless the cam ring 212 is rotated by manual operation or the like, the focus lens 21 moves in the range L2 from the position E1 to the position E2, and the position M1 to the position E1 that is the end on the camera body side or the end on the subject side. Are not moved to the positions M2 to E2. Thereby, the damage by the brush 232 etc. which comprise the encoder 23 moving to the end of both ends can be prevented.

Although details will be described later, in addition to detecting the relative position of the focus lens 21, the lens position detection unit 23 detects the relative position of the focus lens 21. It is also detected whether it is located in a region of positions M1 to E1 or positions M2 to E2 that are ends on the subject side or in a region L2 of positions E1 to E2, and the detection result is detected by a lens drive control unit. 14 to send.

Returning to FIG. 1, the camera body 10 is provided with an image sensor 11 on the optical axis 2. The image sensor 11 is composed of a CCD or the like that converts an image formed by the focus lens 21 or the like into an electric signal, and outputs the photoelectrically converted electric signal to a monitor or the like (not shown). Further, the image sensor 11 outputs a contrast value in a predetermined area of an image that has passed through the focus lens 21 to the focus detection unit 12 when performing an automatic focusing search with the autofocus switch 13 turned on.

The focus detection unit 12 calculates a focus evaluation value from the image output sent from the image sensor 11. This focus evaluation value can be obtained, for example, by extracting a high-frequency component of the image output from the image sensor 11 using a high-frequency transmission filter and integrating it to detect the focus voltage. It can also be obtained by extracting high-frequency components using two high-frequency transmission filters having different cutoff frequencies and integrating them to detect the focus voltage.

Further, the focus detection unit 12 sends a control signal to the lens drive control unit 14 to drive the focus lens at a predetermined sampling interval, obtains a focus evaluation value at each position, and a focus at which the focus evaluation value becomes maximum. The position of the lens 21 is obtained using an arithmetic method such as a linear interpolation method.

Since the position of the focus lens 21 corresponding to the maximum value of the focus evaluation value thus obtained is the in-focus position, the position is sent from the focus detection unit 12 to the lens drive control unit 14 to control the lens drive motor 22. The focus lens 21 is moved to the in-focus position.

When the autofocus switch 13 is turned off, the operator can perform a manual focusing operation by rotating the cam ring 212.

By the way, when the operator manually operates the cam ring 212, the focus lens 21 is positioned at positions M1 to E1 which are the end portions on the camera body side or positions M2 to E2 which are the end portions on the subject side shown in FIG. May be located in an area. However, even if the autofocus switch 13 is turned on in this state, since this area is not a controllable area by the lens drive control unit 14, the focus lens 21 cannot be driven at a predetermined sampling interval.

Therefore, in the present embodiment, the focus search is executed after setting the initial drive as follows. In the following embodiment, a method of searching for the vicinity range of the current position Pn of the focus lens 21 instead of the entire movable range L2 of the focus lens 21 will be described.

FIG. 3 is a flowchart illustrating a focus search routine of the imaging apparatus 1 according to the present embodiment, FIG. 4 is a flowchart illustrating the first embodiment according to a subroutine of step 100 in FIG. 3, and FIG. 6 is an imaging apparatus according to the present embodiment. 7 is a time chart showing an example of the lens position and focus evaluation value in one focus search, and FIG. 7 is a time chart showing the lens position and focus evaluation value in the focus search of the imaging apparatus according to the first embodiment shown in FIG. is there.

First, when the autofocus switch 13 is in the ON state, the focus lens 21 is initially driven in step S100 of the focus search routine shown in FIG. The initial drive refers to an initial operation for moving the focus lens 21 in an operation for searching for a focus position of the focus lens 21. This initial drive will be described later.

When moving the focus lens 21 from the current and initial drive position Pn in position _{P 0} (moving amount D1), to initialize the counter at step S200 (i = 0).

Then, at step S300, (in this example referred to as one step.) A predetermined moving amount D2 from the predetermined position _{P 0} by moving the focus lens 21, and calculates a focus evaluation value at this position _{P 1} (step S400) . Then, the focus lens 21 is intermittently driven by the predetermined movement amount D2 for 8 steps (steps S500 to S600).

After repeating the intermittent drive of the focus lens 21 and the calculation of the focus evaluation value shown in steps S300 and S400, in-focus determination is performed in step S700. The in-focus determination is a process for obtaining the maximum value using a method such as a linear interpolation method based on the focus evaluation value calculated in step S400.

When the maximum focus evaluation value is obtained in the focus determination process in step S700, the process proceeds from step S800 to step S900, and the position Px of the focus lens 21 corresponding to the maximum value is calculated. In step S1000, the focus lens 21 is moved to the in-focus position Px, and the in-focus position search operation is terminated.

If the maximum focus evaluation value is not obtained in step S800, the process jumps to steps S900 and S1000 to end the search for the in-focus position. Incidentally, the case where the focus evaluation value cannot be obtained corresponds to, for example, the case where the focus position Px does not exist in the eight-step intermittent drive range of steps S300, S500, and S600. If it does not exist, for example, the entire searchable range L2 of the focus lens 21 may be searched by the next search operation.

Next, the initial drive of this embodiment will be described.

When the autofocus switch 13 is turned on, the current position of the focus lens 21 is taken into the lens drive control unit 14 from the lens position detection unit 23 in step S111.

Here, the focus lens 21 is located in any one of the ranges L1 in which the mechanical movement by the cam ring 212 or the like is possible, but the current position of the focus lens 21 is in the range L2 in which the lens drive control 14 can be electrically controlled. If it exists, the process proceeds to step S113, and the focus lens 21 is moved in the subject direction (also referred to as an infinite direction), for example, by 4 steps. This is the initial drive, but the 4-step movement in the direction of the subject takes into account the 8-step drive of steps S300 to S600 in FIG. 3, and is set to half the amount of 8 steps. That is, the intent is to search the in-focus position by four steps before and after the current position of the focus lens 21. However, the specific intermittent drive amount is not limited at all, and the value of 8 steps of steps S300 to S600 and the value of 4 steps of step S113 can be set to be larger or smaller.

6 shows the operation and focus of the focus lens 21 when the processing from steps S111 to S112 shown in FIG. 4 to steps S200 to S1000 (steps S300 to S600 are repeated eight times) shown in FIG. The time chart of an evaluation value is shown.

If the current position Pn of the focus lens 21 is in the range L2, firstly the focusing lens 21 and the current position Pn is 8 moving step (D1) to the subject direction (direction of infinity) and a predetermined position _{P 0} (step S100 (S111 to S113 )), while moving the camera body direction (near direction) to 1 step (D2) by the focusing lens 21 from the predetermined position _{P 0,} calculates a focus evaluation value at each location _P 1 to P ₈ (step S400) . Then, the focusing lens 21 to a final search position _{P 8} performs focus determination Once the intermittent driving, and calculates the focus position Px, and moves the focus lens 21 to the focus position Px (step S700~S1000).

Returning to FIG. 4, when the current position Pn of the focus lens 21 does not exist in the range L2 in which electrical control by the lens drive control 14 is possible in step S112, the process proceeds to step S114, and the current position Pn of the focus lens 21 is determined. It is determined whether it is in the vicinity of the closest end, that is, the range M1 to E1 shown in FIG.

When the current position Pn of the focus lens 21 is in the range M1 to E1 in the vicinity of the closest end, the focus lens 21 is moved in the subject direction (infinite direction) by a predetermined amount D1 (10 steps in this example) in step S115. Move. This process is a process for putting the focus lens 21 in a range where predetermined intermittent drive control by the lens drive control unit 14 is possible, and the movement amount when the focus lens 21 is within the range L2, that is, 8 in step S113. The moving amount is larger than the step.

The amount of movement in step 115 is not limited to 10 steps. The amount of movement of the focus lens 21 from the current position Pn to the position E1 is set to the amount of movement obtained by adding the amount of movement in the normal state of step S113, or the focus lens 21. Regardless of the current position Pn, the movement amount from the positions M1 to E1 can be set to the movement amount obtained by adding the movement amount in the normal state in step S113.

FIG. 7 shows the operation of the focus lens 21 when the process from step S111 → S112 → S114 → S115 shown in FIG. 4 to steps S200 to S1000 (steps S300 to S600 are repeated eight times) shown in FIG. And a time chart of focus evaluation values.

If the current position Pn of the focus lens 21 is in the range M1～E1, firstly the focusing lens 21 from the current position Pn is moved 10 steps to the object direction (direction of infinity) and a predetermined position _{P 0} (step S100 (S111 → S112 → S114 → S115)), the focus evaluation value is calculated at each of the positions P _{1 to} P ₈ while moving the focus lens 21 from the predetermined position P ₀ to the camera body direction (closest direction) which is the reverse direction step by step. (Step S400). Then, the focusing lens 21 to a final search position _{P 8} performs focus determination Once the intermittent driving, and calculates the focus position Px, and moves the focus lens 21 to the focus position Px (step S700~S1000).

Although not shown in the flowchart of FIG. 3, when the position of the focus lens 21 reaches E1 during the routine process of steps S300 → S400 → S500 → S600, the intermittent drive is terminated there, and the step The process proceeds to the focus determination in S700.

In the present embodiment, even if the current position Pn of the focus lens 21 is in the range M1 to E1 where the drive control by the lens drive control unit 14 is not possible, the control is performed to move to the controllable range L2 when it is detected. The inability to search the focus position due to the current position of the focus lens 21 can be avoided.

Returning to FIG. 4, when the current position Pn of the focus lens 21 does not exist in the range L2 in which electrical control by the lens drive control 14 is possible and does not exist in the vicinity of the close end M1 to E1 in step S112. The current position Pn of the focus lens 21 exists in the range E2 to M2 (also referred to as the vicinity of the infinite end) shown in FIG.

When the current position Pn of the focus lens 21 is in the range E2 to M2 near the infinite end, the focus lens 21 is moved by a predetermined amount (one step in this example) in the camera body direction (closest direction) in step S116. The unit drive is repeated until the lens drive control unit 14 enters a range L2 in which drive control is possible (step S117). This process is a process for putting the focus lens 21 in the range L2. In this example, the unit drive amount is set to one step, but the specific numerical value is not limited and may be two steps or more.

FIG. 8 shows the focus lens 21 when the processing from step S111 → S112 → S114 → S116 → S117 shown in FIG. 4 to steps S200 to S1000 (steps S300 to S600 are repeated eight times) shown in FIG. The time chart of the operation and focus evaluation value is shown.

When the current position Pn of the focus lens 21 is in the range E2 to M2, first, the focus lens 21 is moved step by step from the current position Pn to the camera body direction (closest direction) until the focus lens 21 enters the range L2. repeating, After entering the focusing lens 21 is in the range L2, to the position and the predetermined position _{P 0} (step S100 (S111 → S112 → S114 → S116 → S117)). While moving step by step the focus lens 21 to the camera body direction (nearest direction) from the predetermined position _{P 0,} it calculates a focus evaluation value at each location _P 1 to P ₈ (step S400). Then, the focusing lens 21 to a final search position _{P 8} performs focus determination Once the intermittent driving, and calculates the focus position Px, and moves the focus lens 21 to the focus position Px (step S700~S1000).

FIG. 9 is a flowchart showing the second embodiment according to the subroutine of step 100 in FIG. 3, and FIG. 10 is a time chart showing the lens position and the focus evaluation value in the focus search of the imaging apparatus according to the second embodiment.

In this example, when the current position Pn of the focus lens 21 is located in the camera body side range M1 to E1 (near the close end) in steps S122 and S124, the focus lens 21 is moved in the subject direction in step S125. This is repeated until the focus lens 21 enters the range L2 (step S126). When the focus lens 21 enters the range L2, the focus lens 21 is further moved from that position in step S127. Is moved in the subject direction (infinite direction), for example, 8 steps, and the position is set to a predetermined position P ₀ . This corresponds to the initial driving in this example.

FIG. 10 shows the focus when the processing from step S121 → S122 → S124 → S125 → S126 → S127 shown in FIG. 9 to steps S200 to S1000 (steps S300 to S600 are repeated eight times) shown in FIG. The time chart of operation | movement of a lens 21 and a focus evaluation value is shown.

When the current position Pn of the focus lens 21 is in the range M1 to E1, the focus lens 21 is first moved from the current position Pn to the subject direction (infinite direction) step by step, and this is repeated until the focus lens 21 enters the range L2. Once focusing lens 21 has a range L2, the position _{P 00} more moved 8 steps to the object direction (direction of infinity) from the its position as the predetermined position _{P 0} (step S100 (S121 → S122 → S124 → S125 → S126 → S127)).

Then, while moving by one step the focus lens 21 to the camera body direction (nearest direction) from the predetermined position _{P 0,} it calculates a focus evaluation value at each location _P 1 to P ₈ (step S400). Then, the focusing lens 21 to a final search position _{P 8} performs focus determination Once intermittently driven, to calculate the focus position Px, and moves the focus lens 21 to the focus position Px (step S700~S1000).

Note that the processes of steps S121 → S122 → S123 and steps S121 → S122 → S124 → S128 → S129 shown in FIG. 9 are the processes of steps S111 → S112 → S113 and steps S111 → S112 → S114 → S116 shown in FIG. → Since the process is the same as S117, the description thereof is omitted.

FIG. 11 is a flowchart showing a third embodiment according to the subroutine of step 100 in FIG. 3, and FIG. 12 is a diagram showing a lens position and a focus evaluation value in the focus search of the imaging apparatus according to the third embodiment.

In this example, when the current position Pn of the focus lens 21 is located in the camera body side range M1 to E1 (near the closest end) in steps S132 and S134, the focus lens 21 is moved to the range L2 in step S135. It is moved directly to the predetermined position Pm, and this position is set as the predetermined position. This position Pm is stored in advance in the lens drive control unit 14, and the focus lens 21 is moved using the lens position detection unit 23 or the like that can detect the absolute position.

FIG. 12 shows the operation of the focus lens 21 when the process from step S131 → S132 → S134 → S135 shown in FIG. 11 to steps S200 to S1000 (steps S300 to S600 are repeated eight times) shown in FIG. And a time chart of focus evaluation values.

When the current position Pn of the focus lens 21 is in the range M1 to E1, the focus lens 21 is first moved from the current position Pn to a predetermined position Pm within the range L2 (step S100 (S131 → S132 → S134 → S135)). While moving the focus lens 21 from the predetermined position Pm to the camera body direction (closest direction) step by step, focus evaluation values are calculated at the respective positions P _{1 to} P ₈ (step S400). Then, the focusing lens 21 to a final search position _{P 8} performs focus determination Once the intermittent driving, and calculates the focus position Px, and moves the focus lens 21 to the focus position Px (step S700~S1000).

Note that the processes of steps S131 → S132 → S133 and steps S131 → S132 → S134 → S136 → S137 shown in FIG. 11 are the processes of steps S111 → S112 → S113 and steps S111 → S112 → S114 → S116 shown in FIG. → Since the process is the same as S117, the description thereof is omitted.

According to the present embodiment, since the focus lens 21 can be moved to the predetermined position Pm within the range L2 in which the drive control by the lens drive control unit 14 can be performed by only one drive, the time required for the initial drive can be shortened. it can.

  In the above-described embodiment, the focus lens 21 of the imaging apparatus 1 has been described as an example. However, any lens other than the focus lens can be similarly applied as long as it is a driving lens.

  In the above-described embodiment, the focus lens 21 is moved in the camera body direction for the intermittent drive after the initial drive, but the focus lens 21 is intermittently driven in the subject direction to search for the in-focus position. It can also be done. In this case, the initial driving direction is opposite to the initial driving direction of the above-described embodiment.

1 is a block diagram illustrating an imaging apparatus according to an embodiment of the present invention. It is sectional drawing which shows the moving mechanism of the focus lens which concerns on embodiment of this invention. It is a flowchart which shows the focus search routine of the imaging device which concerns on embodiment of this invention. It is a flowchart which shows 1st Embodiment which concerns on the subroutine of step 100 of FIG. It is a figure which shows the lens drive range which concerns on embodiment of this invention. It is a figure which shows an example of the lens position and focus evaluation value in the focus search of the imaging device which concerns on embodiment of this invention. FIG. 5 is a diagram illustrating a lens position and a focus evaluation value in a focus search of the imaging apparatus according to the first embodiment illustrated in FIG. 4. FIG. 5 is a diagram illustrating a lens position and a focus evaluation value in a focus search of the imaging apparatus according to the first embodiment illustrated in FIG. 4. It is a flowchart which shows 2nd Embodiment which concerns on the subroutine of step 100 of FIG. It is a figure which shows the lens position and focus evaluation value in the focus search of the imaging device which concerns on 2nd Embodiment shown in FIG. It is a flowchart which shows 3rd Embodiment which concerns on the subroutine of step 100 of FIG. It is a figure which shows the lens position and focus evaluation value in the focus search of the imaging device which concerns on 3rd Embodiment shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Imaging device; 10 ... Camera body; 11 ... Image sensor; 12 ... Focus detection part 13 ... Autofocus switch; 14 ... Lens drive control part 20 ... Lens barrel; 21 ... Focus lens; Lens position detector

Claims (10)

When the lens is moved in the optical axis direction of the lens, a control unit that repeats driving for each predetermined second movement amount after performing an initial drive for driving the first movement amount from the current lens position of the lens. A lens driving device comprising:
The lens driving device according to claim 1, wherein the control means sets the first movement amount according to the current lens position. The lens driving device according to claim 1,
A lens driving device comprising: a moving unit capable of moving the lens in a second range that exceeds the first range in the optical axis direction in which the position of the lens can be controlled by the control unit. The lens driving device according to claim 2,
When the lens is located in the second range, the control means replaces the first movement amount with a lens movement amount corresponding to the second range with respect to the first movement amount. A lens driving device characterized in that the initial driving is performed with an added movement amount. The lens driving device according to claim 2,
When the lens is in the second range, the control means performs the initial drive with a movement amount corresponding to the second range instead of the first movement amount. A lens driving device. The lens driving device according to claim 2,
When the lens is located in the second range, the control unit repeatedly repeats the initial unit driving amount in the direction in which the first range exists instead of the first moving amount. A lens driving device that performs driving. The lens driving device according to claim 2,
When the lens is located in the second range, the control means moves the lens to a predetermined position in the first range instead of the initial drive. . The lens driving device according to claim 1 or 2,
The control means sets the first movement amount based on the lens position and the driving direction for each second movement amount. The lens driving device according to any one of claims 1 to 7,
A focus adjustment device comprising: a focus detection unit that detects a focus adjustment state of the lens by detecting a focus evaluation value based on a contrast value of an image by the lens;
The focus adjustment device, wherein the focus detection unit obtains the focus evaluation value every time the lens is driven with the second movement amount after the initial drive. When the lens is moved in the optical axis direction of the lens, the lens driving is repeated for each predetermined second movement amount after the lens is initially driven to drive the first movement amount from the current lens position. A method,
A lens driving method, wherein the first movement amount is set according to the current lens position. An imaging apparatus comprising the lens driving device according to claim 1.

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