Imaging device, control method, and program

Abstract

To provide an image pickup apparatus capable of acquiring an image with proper exposure while properly reducing blur.SOLUTION: An image pickup apparatus (200) includes: an image sensor (301) configured to acquire an image; an image blur correction mechanism (300) configured to reduce blur by moving the image sensor on the basis of a shake amount detected by shake detection means (217a); a shutter apparatus (218) including a front blade group (4) and a rear blade group (5); and control means (216a) configured to provide control on image blur correction by the image blur correction mechanism. The image sensor has a first mode for acquiring the image on the basis of light passing through an area formed by the front blade group and the rear blade group, and a second mode for acquiring the image on the basis of light passing through an area between an electronic front curtain of the image sensor and the rear blade group. In the first mode, the control means provides the control on the image blur correction. In the second mode, the control means determines whether or not to provide the control on the image blur correction, on the basis of a shutter speed of the shutter apparatus.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an imaging apparatus having a mechanical shutter shooting mode and an electronic front curtain shooting mode. [Background technology]

[0002] Conventionally, imaging devices having a mechanical shutter shooting mode are known. In the mechanical shutter shooting mode, a slit formed by the mechanical shutter (two shutter blades, a leading blade group and a trailing blade group) of a focal plane shutter mounted in the camera continuously exposes the imaging surface. Also known is an imaging device having an electronic front-curtain shooting mode that uses both a mechanical shutter and an electronic shutter to perform imaging operations. Such imaging devices perform imaging using the trailing blade group (rear curtain) of the focal plane shutter and the electronic front curtain, which performs a charge accumulation start scan (reset scan) of the imaging element prior to the travel of the rear curtain.

[0003] In recent years, imaging devices have been proposed that include image stabilization mechanisms that perform image stabilization by moving the image sensor. However, when image stabilization is performed during electronic front-curtain photography and the image sensor is driven, the amount of light that passes through the area between the reset scan of the image sensor's pixels and the rear blade group and exposes the image sensor changes, making it impossible to capture a proper image. The width of the area between the reset scan of the image sensor's pixels and the rear blade group, which is made up of a mechanical shutter, becomes narrower the faster the shutter speed, so the impact of driving the image sensor on image exposure is significant.

[0004] Patent Document 1 discloses a camera that allows image stabilization control when the shutter speed during shooting is slower than a predetermined shutter speed, and prohibits image stabilization control when the shutter speed is faster than the predetermined shutter speed. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-182447 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the camera disclosed in Patent Document 1 prohibits image blur correction in both mechanical shutter and electronic front-curtain shooting modes when the shutter time is faster than a predetermined shutter time. Therefore, in mechanical shutter shooting when the shutter time is faster than the predetermined shutter time, image sensor image blur correction and lens image blur correction are not performed, which may result in blurred images.

[0007] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an imaging device, a control method, and a program that are capable of acquiring an image with appropriate exposure and appropriate shake correction. [Means for solving the problem]

[0008] An image pickup apparatus according to one aspect of the present invention includes an image pickup element that acquires an image, a blur correction mechanism that corrects blur by moving the image pickup element based on the amount of blur detected by a blur detection means, a shutter device, and a control means that performs blur correction control of the blur correction mechanism, wherein the image pickup apparatus has a first mode in which the image is acquired based on light that passes through an area between an electronic front curtain of the image pickup element and a rear blade group of the shutter device, and a second mode in which the image is acquired by a method different from the method used in the first mode, wherein the control means performs the blur correction control in the first mode and the second mode when the shutter speed is slower than a predetermined shutter speed, and wherein the control means does not perform the blur correction control in the first mode and performs the blur correction control in the second mode when the shutter speed is faster than the predetermined shutter speed.

[0009] Other objects and features of the present invention are illustrated in the following examples. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide an imaging device, a control method, and a program that can acquire an image by appropriately performing image blur correction with appropriate exposure. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 2 is a block diagram of an imaging device in each embodiment. [Figure 2(a)] FIG. 2 is an exploded perspective view of the shutter device in each embodiment. [Figure 2(b)] FIG. 2 is an exploded perspective view of the shutter device in each embodiment. [Figure 3] FIG. 2 is a plan view of the shutter device in the respective embodiments in a standby state for photographing. [Figure 4] FIG. 2 is an exploded perspective view of the image stabilization mechanism in each embodiment, as viewed from the subject side. [Figure 5] FIG. 2 is an exploded perspective view of the image stabilization mechanism in each embodiment, as viewed from the imaging element side. [Figure 6] FIG. 2 is an exploded perspective view of a movable part of the image stabilization mechanism in each embodiment. [Figure 7] FIG. 2 is a perspective view of a movable part of the image stabilization mechanism in each embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. [Example]

[0013] First, an imaging device according to a first embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 is a block diagram of an imaging device 200. The imaging device 200 is configured to include a camera body (imaging device body) 201 having an imaging element 301, and an imaging lens 202 (interchangeable lens, lens device) that is detachable from the camera body 201. The imaging device 200 can select between a mechanical shutter system using the leading blade 4 and trailing blade 5 of a focal plane shutter 218, and a reset scan (electronic leading curtain scanning) using the imaging element 301 and an electronic leading curtain system using the trailing blade 5. However, this embodiment is not limited to this, and can also be applied to an imaging device in which the imaging lens and the imaging device body are configured as an integrated unit.

[0014] The imaging lens 202 includes an imaging optical system 401 having a shake correction lens 401b. In this embodiment, a plane perpendicular to the optical axis 401a of the imaging optical system 401 is defined as an optical axis perpendicular plane 401c. The imaging lens 202 may also include an aperture.

[0015] The camera body 201 and the imaging lens 202 each include a shake correction control unit 216a, 216b, a shake detection unit 217a, 217b, and a shake correction mechanism 300, 400. The imaging element 301 is configured using a CMOS image sensor, a CCD image sensor, or the like, and is disposed within the camera body 201 with its imaging surface 301a facing the subject (not shown) and perpendicular to an optical axis 401a. The imaging element 301 generates an image signal by photoelectrically converting, on the imaging surface 301a, a subject light beam formed by an imaging optical system 401 (described later). The imaging optical system 401 is configured using a group of lenses (not shown) within the imaging lens 202, and forms an image of the subject light beam (not shown) on the imaging surface 301a of the imaging element 301. The imaging optical system 401 includes a shake correction lens 401b (described later).

[0016] An optical axis 401a is formed by an imaging optical system 401 in the imaging lens 202. In the imaging device 200, in order to accurately position the imaging element 301 with respect to the optical axis 401a, the imaging lens 202 and the imaging element 301 are both connected via a mount member (not shown) in the camera body 201. In this case, the imaging element 301 is connected to a frame member (not shown) of the camera body 201 via a shake correction mechanism 300 (described later). In addition, the imaging lens 202 is connected to a frame member (not shown) via a mount member (not shown).

[0017] In the imaging device 200, the image sensor 301 and the blur correction lens 401b each constitute a blur correction unit. These components translate or rotate on a plane 401c perpendicular to the optical axis to perform blur correction. More specifically, if the image sensor 200 changes its orientation relative to a subject (not shown) during imaging, i.e., if the subject shakes, the imaging position of the subject light beam on the imaging surface 301a of the image sensor 301 changes, resulting in blur in the image. If such a change in orientation is sufficiently small, the change in the imaging position is uniform across the imaging surface 301a and can be considered as a translation or rotation movement on the plane 401c perpendicular to the optical axis (image plane blur). Therefore, blur correction can be performed by controlling the translation or rotation movement of the image sensor 301 on the plane 401c perpendicular to the optical axis to reduce (cancel) this image plane blur. Furthermore, the blur correction lens 401b can refract the optical axis 401a by translating on the plane 401c perpendicular to the optical axis. Therefore, blur correction can be performed by controlling the translational movement of the blur correction lens 401b on the plane 401c orthogonal to the optical axis so as to reduce (cancel) the image plane blur described above. Note that the principles and control of blur correction are well known, and therefore a more detailed explanation thereof will be omitted.

[0018] Image sensor 301 and image blur correction lens 401b, which are image blur correction means, are held movably within a certain range on optical axis 401a and plane 401c perpendicular to the optical axis by image blur correction mechanisms 300 and 400, respectively, and their movement is controlled. Generally, the wider the movable range, the greater the amount of image blur that can be corrected, making it easier to correct blur in a variety of shooting scenes. However, as camera body 201 and image pickup lens 202 become larger, the movable range is set to an appropriate required amount.

[0019] The image stabilization mechanism (first image stabilization mechanism) 300 has a fixed section, a movable section, and multiple drive force generation sections, all of which are not shown in FIG. 1. The fixed section supports the movable section with three degrees of freedom and allows it to translate and rotate within a predetermined drive plane relative to the fixed section. The fixed section is fixed to a frame member (not shown), and the movable section holds the image sensor 301, allowing the image sensor 301 to translate and rotate in the direction of a plane 401c orthogonal to the optical axis. In other words, the image stabilization mechanism 300 constitutes a three-axis drive controllable drive device, or what is known as an XYθ stage.

[0020] Like the image stabilization mechanism 300, the image stabilization mechanism (second image stabilization mechanism) 400 has a fixed section, a movable section, and multiple drive force generation sections, all of which are not shown in FIG. 1. The fixed section supports the movable section with two degrees of freedom and translates it within a predetermined drive plane relative to the fixed section. The fixed section is fixed to a frame member (not shown) via the housing of the imaging lens 202 and a mount member (not shown), and the movable section holds the image stabilization lens 401b, allowing the image stabilization lens 401b to translate in a plane 401c orthogonal to the optical axis. In other words, the image stabilization mechanism 400 constitutes a drive device capable of two-axis drive control, a so-called XY stage.

[0021] The shake correction control means 216a, 216b of the camera body 201 and the imaging lens 202 control the drive of the shake correction mechanisms 300, 400, respectively, thereby controlling the movement of the image sensor 301 and the shake correction lens 401b and performing shake correction. At this time, the movement target values ​​of the image sensor 301 and the optical axis 401a are both calculated based on shake information of the imaging device 200. The shake information can be obtained from the shake detection means 217a of the camera body 201 and the shake detection means 217b of the imaging lens 202.

[0022] The shake detection means 217a and 217b detect information related to the amount of angular change and movement of the image capture device 200 in each direction. For example, they are both configured with a gyro sensor, an acceleration sensor, or the like, and detect the angular velocity and acceleration of the image capture device 200 in each direction. Therefore, the shake correction control means 216a of the camera body 201 and the shake correction control means 216b of the imaging lens 202 can calculate the amount of angular change and movement of the image capture device 200 in each direction as shake information by integrating these angular velocity and acceleration. In this way, the shake correction control means 216a and 216b calculate movement target values ​​for the image sensor 301 and the shake correction lens 401b and control the driving of the shake correction mechanisms 300 and 400. Note that the image capture device 200 does not necessarily have to have the shake correction mechanism 400. In this case, the shake correction means of the imaging lens 202 (the shake correction lens 401b) is fixedly disposed with respect to the optical axis 401a.

[0023] The focal plane shutter (shutter device) 218 ​​is disposed on the subject side of the image sensor 301, and as will be described later, has a leading blade group 4, a trailing blade group 5, a leading drive source 24, and a trailing drive source 25. A CPU (control means) 204 controls the operation (start timing of blade group travel, motor drive) of the focal plane shutter 218 (leading blade group 4, trailing blade group 5, leading drive source 24, and trailing drive source 25) via a shutter drive circuit 205. The CPU 204 also controls the scan pattern of reset scanning by a vertical drive modulation circuit 208, as will be described later.

[0024] The first switch (SW1) 210 is a switch for starting preparation for imaging. The second switch (SW2) 211 is a switch for starting imaging. The first switch 210 and the second switch 211 are configured as a two-stage switch, with the first switch 210 being turned on with a first stroke and the second switch 211 being turned on with a second stroke.

[0025] The lens control means 215 outputs to the CPU 204 imaging condition information (information about the state of the imaging lens 202, i.e., lens information) such as the focal length, aperture diameter (aperture value), exit pupil diameter, and distance between the exit pupil and the image sensor 301 of the imaging lens 202. The lens control means 215 also controls the operation (drive) of the imaging lens 202 (including the aperture) in response to instructions from the CPU 204. The CPU 204 controls and performs calculations for the signal processing circuit 209, vertical drive modulation circuit (scanning means) 208, shutter drive circuit 205, and lens control means 215. The CPU 204 also supplies a scan clock (horizontal drive pulse) and predetermined control pulses to the image sensor 301 via the pulse generation circuit 207.

[0026] Of the scan clocks generated by the pulse generation circuit 207, the clock for vertical scanning is modulated to a predetermined clock frequency by the vertical drive modulation circuit 208 and input to the image sensor 301. The vertical drive modulation circuit 208 sets a scan pattern (scan curve) for reset scanning as the electronic front curtain based on a command from the CPU 204. The vertical drive modulation circuit 208 is a scanning means as the electronic front curtain, and determines the scan pattern for reset scanning. Based on a command from the CPU 204, the vertical drive modulation circuit 208 performs reset scanning of accumulated charges sequentially from top to bottom or bottom to top, i.e., scanning to start charge accumulation for each pixel of the image sensor 301.

[0027] The pulse generating circuit 207 also outputs a clock signal to the signal processing circuit 209. The signal processing circuit 209 generates image data by performing predetermined processing (such as color processing and gamma correction) on the signal read out from the image sensor 301. The recording medium 212 records the image data processed by the signal processing circuit 209. The display unit 213 is configured with a liquid crystal display (LCD) or the like, and displays captured images, various menu screens, and the like. The RAM (Random Access Memory) 214 is connected to the signal processing circuit 209 and is a storage means for temporarily storing image data and the like.

[0028] Next, the configuration of the focal plane shutter 218 in this embodiment will be described with reference to Figures 2(a) and (b) and Figures 3(a) and (b). Figure 2(a) is an exploded perspective view of the focal plane shutter 218 as seen from the side where the image sensor 301 is attached (image sensor side). Figure 2(b) is an exploded perspective view as seen from the side where the imaging lens 202 is attached (subject side). Figure 3(a) is a plan view of the focal plane shutter 218 in a shooting standby state as seen from the image sensor side. Figure 3(b) is a plan view of the focal plane shutter 218 in a shooting standby state as seen from the subject side.

[0029] A partition plate 2 and a cover plate 3 are attached in this order at a specified interval to the object side of the shutter base plate 1. Similar shaped apertures 1a, 2a, and 3a are formed in the three plate members of the shutter base plate 1, partition plate 2, and cover plate 3, and a rectangular exposure opening formed by overlapping the three apertures 1a to 3a defines the light beam that passes through the focal plane shutter 218. Two blade chambers are formed between these three plate members, and within these blade chambers, shutter blades each consisting of a light-shielding blade and a blade arm are individually arranged as a leading blade group 4 and a trailing blade group 5.

[0030] To improve the strength of the shutter base plate 1 and to tighten the various metal shafts, a metal auxiliary base plate 6 is fastened to the shutter base plate 1 with screws. A plurality of shafts 6a, 6b, 6c, 6d, 6e, and 6f are erected on the auxiliary base plate 6 on the imaging element side, and a leading driving member 7, a trailing driving member 8, a leading locking member 9, and a trailing locking member 10 are rotatably attached to the shafts 6a, 6b, 6c, and 6d, respectively. Furthermore, a leading driving source 24 and a trailing driving source 25, such as a DC motor, are fastened to the subject side of the auxiliary base plate 6 with screws, respectively.

[0031] A gear base plate 26 is fastened with screws to the subject side of the auxiliary base plate 6. The leading cam gear 22 and the rear cam gear 23 are rotatably attached to shafts 26a and 26b, respectively, which are erected on the imaging element side of the gear base plate 26. A leading reduction gear group 27 is rotatably supported on shafts 26c and 26e on the imaging element side of the gear base plate 26, and a rear reduction gear group 28 is rotatably supported on shafts 26d and 26f. The output shaft 24a of the leading drive source 24, the leading reduction gear group 27, and the leading cam gear 22 are engaged with each other, and the main power shaft 25a of the rear drive source 25, the rear reduction gear group 28, and the rear cam gear 23 are engaged with each other. This transmits the torque of the leading drive source 24 and the rear drive source 25 to the leading cam gear 22 and the rear cam gear 23, respectively. The leading drive source 24 and the rear drive source 25 can be used in both forward and reverse rotation. In this embodiment, the direction in which the front cam gear 22 and the rear cam gear 23 rotate counterclockwise in FIG. 3(a) is defined as the forward rotation.

[0032] 3A is a line passing through the center of the exposure aperture. Regarding the components that drive the leading blade group 4, in descending order of proximity to line A-A', shaft 26a, which is the rotation shaft of leading cam gear 22, shaft 6a, which is the rotation shaft of leading driving member 7, shaft 26c, which is the rotation shaft of leading reduction gear group 27, and output shaft 24a of leading driving source 24 are arranged. Regarding the arrangement of the components that drive the trailing blade group 5, in descending order of proximity to line A-A', shaft 26b, which is the rotation shaft of rear cam gear 23, shaft 6b, which is the rotation shaft of rear driving member 8, shaft 26d, which is the rotation shaft of rear reduction gear group 28, and main power shaft 25a of rear driving source 25 are arranged.

[0033] The above-described arrangement is made possible by operating the focal plane shutter 218 with two drive sources, front drive source 24 and rear drive source 25, distributing the torque required to drive front blade group 4 and rear blade group 5, and reducing the size of front cam gear 22 and rear cam gear 23. This allows the entire focal plane shutter 218 to be made smaller.

[0034] The drive members 7 and 8 are biased counterclockwise by the biasing forces of drive springs 12 and 13 as viewed from the imaging element side. Cam gears 22 and 23 rotate the drive members 7 and 8 clockwise against the biasing forces of the drive springs 12 and 13. When the drive members 7 and 8 are in the set position, locking portions 7a and 8a on the drive members 7 and 8 engage with locking portions 9a and 10a on the locking members 9 and 10, thereby locking the drive members 7 and 8. Drive pins 7b and 8b are provided on the drive members 7 and 8, and they pass through three pairs of elongated holes 1b and 1c, 6g and 6h, and 3b and 3c on the shutter base plate 1, auxiliary base plate 6, and cover plate 3, respectively, and engage with elongated holes 4c and 5c on the blade arms 4a and 5a. Rollers 14, 15, 16, and 17 are rotatably attached to the drive members 7 and 8. The setting operation of the leading driving member 7 by the leading cam gear 22 via the rollers 14 and 15, and the setting operation of the rear driving member 8 by the rear cam gear 23 via the rollers 16 and 17 are preferably performed.

[0035] In this embodiment, the leading cam gear 22 is formed with cam surfaces 22a and 22b, and the trailing cam gear 23 is formed with cam surfaces 23a and 23b. Two rollers 14, 15 and two rollers 16, 17 attached to the driving members 7, 8, respectively, sequentially come into contact with the two cam surfaces to perform the setting operation. This equalizes the amount of rotation of the driving members 7, 8 and the cam gears 22, 23 during the setting operation, thereby reducing the maximum load during the setting operation. However, depending on the tolerances of the related parts, the driving members 7, 8 may not be positioned within the allowable setting range. In such cases, the setting positions of the driving members 7, 8 can be adjusted by replacing the rollers 15, 17.

[0036] The blade phase detecting means 29, 30 and the cam phase detecting means 31, 32 are non-contact optical phase detecting means, and are attached to the holding base plate 11 arranged on the imaging element side of the auxiliary base plate 6. In this embodiment, photointerrupters are used as the blade phase detecting means 29, 30 and the cam phase detecting means 31, 32. The blade phase is detected by determining whether the blade phase detecting means 29, 30 is shielded from light by the detection target portions 7f, 8f of the drive members 7, 8. The cam phase is detected by determining whether the cam phase detecting means 31, 32 is shielded from light by the detection target portions 22c, 23c of the cam gears 22, 23. In this embodiment, the cam phase detecting means 31, 32 use two photointerrupters 31a, 31b and two photointerrupters 32a, 32b, respectively, to determine the phase.

[0037] In this embodiment, the leading blade group 4 and the trailing blade group 5 each include two blade arms 4a, 4b, 5a, and 5b and four sets of light-shielding blades 4d, 4e, 4f, 4g, 5d, 5e, 5f, and 5g. The leading blade group 4 has two blade arms 4a and 4b pivotally mounted on shafts 6i and 6j on the subject side of the auxiliary base plate 6. The four blades 4d, 4e, 4f, and 4g are pivotally supported on the blade arms 4a and 4b via a connecting shaft 33. As described above, the blade arm 4a has an elongated hole 4c formed therein, into which the drive pin 7b of the leading driving member 7 is engaged. The trailing blade group 5 has two blade arms 5a and 5b pivotally mounted on shafts 6k and 6l on the subject side of the auxiliary base plate 6. The four light-shielding blades 5d, 5e, 5f, and 5g are pivotally supported on the blade arms 5a and 5b via the connecting shaft 33. As described above, the blade arm 5a has an elongated hole 5c formed therein, into which the drive pin 8b of the rear drive member 8 is engaged. The focal plane shutter 218 is fixed to a frame member (not shown).

[0038] Next, the configuration of image stabilization mechanism 300 as a drive device in this embodiment will be described with reference to Figures 4 and 5. Figure 4 is an exploded perspective view of image stabilization device 300 as seen from the subject side. Figure 5 is an exploded perspective view of image stabilization device 300 as seen from the imaging element side. Image stabilization mechanism 300 includes fixed part 300a and movable part 300b.

[0039] The fixed portion 300a includes a fixed member 302, a first frame member 303a, a second frame member 303b, a third frame member 303c, a first magnet group 305a, a second magnet group 305b, and a third magnet group 305c. The fixed member 302 is provided with a first opening 302a, a second opening 302b, and a third opening 302c. The first opening 302a, the second opening 302b, and the third opening 302c are engaged with the outer shapes of the first frame member 303a, the second frame member 303b, and the third frame member 303c, respectively. First, second, and third magnet groups 305a, 305b, and 305c are engaged with the inner diameters of first, second, and third frame members 303a, 303b, and 303c, respectively. Each of first, second, and third magnet groups 305a, 305b, and 305c forms a Halbach magnetic circuit with three magnets having different magnetization directions.

[0040] Fixed part 300a includes first rear yoke 306a, second rear yoke 306b, and a plurality of spacer members 304. First rear yoke 306a is disposed to cover first magnet group 305a, and second rear yoke 306b is disposed to cover second magnet group 305b and third magnet group 305c, respectively, when projected onto plane 401c orthogonal to the optical axis. These come into contact with spacer members 304 disposed between them and fixed part 302, and their positions in the direction of optical axis 401a are determined.

[0041] The fixed part 300a also includes a first pillar member 307a, a second pillar member 307b, and a third pillar member 307c, each having an abutment surface 307d. The first pillar member 307a, the second pillar member 307b, and the third pillar member 307c each engage with the fixed part 302, and the abutment surface 307d abuts against the fixed part 302, thereby defining the position along the optical axis 401a.

[0042] As described above, the positions of first rear yoke 306a and second rear yoke 306b relative to fixed member 302 are determined by multiple spacer members 304. The positions of first pillar member 307a, second pillar member 307b, and third pillar member 307c relative to fixed member 302 are determined by abutment surfaces 307d. At the determined position, first rear yoke 306a sandwiches fixed member 302 and is fixed to first pillar member 307a and second pillar member 307b with screw members 308. At the determined position, second rear yoke 306b is fixed to fixed member 302 with screw members 308, and is fixed to third pillar member 307c with fixed member 302 sandwiched between them. As a result, the first rear yoke 306a, the second rear yoke 306b, the first pillar member 307a, the second pillar member 307b, and the third pillar member 307c are fixed to the fixing member 302.

[0043] First magnet group 305a, second magnet group 305b, and third magnet group 305c each have flange portion 305d. Fixing member 302 and first rear yoke 306a and second rear yoke 306b are fixed by pressing flange portion 305d. Note that in this embodiment, multiple magnets are arranged to form a Halbach magnetic circuit, but a configuration other than a Halbach magnetic circuit, such as magnetizing multiple poles on a single magnet, may also be used.

[0044] The fixed part 300a includes a restricting member 309 and a fastening member 310, and the restricting member 309 is fixed to the fixed part 302 by the fastening member 310. As will be described in detail later, the restricting member 309 and the fastening member 310 restrict the movement of the movable part 300b. The fixed part 300a also includes a front yoke 311, and the front yoke 311 is fixed to the first pillar member 307a, the second pillar member 307b, and the third pillar member 307c with screw members 308. The fixed part 300a includes a magnet 312, and the magnet 312 is fixed to the fixed part 302 with an adhesive or the like.

[0045] Next, the configuration of the movable unit 300b will be described with reference to FIGS. 6 and 7. FIG. 6 is an exploded perspective view of the movable unit 300b of the image stabilizer 300. As shown in FIG. 6, the movable unit 300b includes a movable member 313 and an image sensor 301. The image sensor 301 is fixed to the movable member 313 with an adhesive or the like. The first mask 314a, the second mask 314b, the infrared absorption filter 315a, and the optical low-pass filter 315b are held by a holder member 316 and a metal holder 317, and are fixed to the image sensor 301 with an adhesive or the like. The first mask 314a and the second mask 314b prevent unwanted light from outside the imaging optical path from entering the image sensor 301. The optical low-pass filter 315b is provided with a vibration mechanism 318 that vibrates to remove foreign matter adhering to its surface. However, the detailed principles and control thereof are well known, and therefore will not be described here.

[0046] Furthermore, movable part 300b includes first coil 319a, second coil 319b, third coil 319c, drive FPC 320, first attraction metal plate 321a, and second attraction metal plate 321b. Movable member 313 includes first opening 313a, second opening 313b, and third opening 313c. First coil 319a is disposed inside first opening 313a, second coil 319b is disposed inside second opening 313b, and third coil 319c is disposed inside third opening 313c, and are fixed to movable member 313 with an adhesive or the like.

[0047] The driving FPC 320 is disposed so as to cover the first coil 319a, the second coil 319b, and the third coil 319c when projected onto the optical axis orthogonal plane 401c, and is fixed to the movable member 313 with an adhesive or the like. The first coil 319a, the second coil 319b, and the third coil 319c are electrically connected to the driving FPC 320, and current is passed through the driving FPC 320 as determined by the image stabilization control means 216a.

[0048] The first and second attraction metal plates 321a and 321b are fixed to the drive FPC 320 with an adhesive or the like. The first and second attraction metal plates 321a and 321b overlap with the first and third magnet groups 305a and 305c of the fixed part 300a, respectively, when projected onto the optical axis orthogonal plane 401c. These are attracted to the first and third magnet groups 305a and 305c, thereby generating a biasing force on the movable part 300b.

[0049] FIG. 7 is a perspective view of the movable part 300b. As shown in FIG. 7, the driving FPC 320 includes a first detector 322a, a second detector 322b, and a third detector 322c. The first detector 322a is disposed inside the first coil 319a, the second detector 322b is disposed inside the second coil 319b, and the third detector 322c is disposed inside the third coil 319c. The first detector 322a, the second detector 322b, and the third detector 322c are Hall elements. As described below, these detect the magnetic force of the opposing magnets, and the image stabilization control unit 216a calculates the position of the movable part 300b on the plane 401c orthogonal to the optical axis relative to the fixed part 300a.

[0050] The movable part 300b includes a third attraction metal plate 321c, which is fixed to the movable member 313 with a screw member 308. The third attraction metal plate 321c faces the magnet 312 of the fixed part 300a, and is attracted to the magnet 312, thereby generating a biasing force on the movable part 300b.

[0051] First rolling member 323a, second rolling member 323b, and third rolling member 323c are disposed inside first enclosure 313d, second enclosure 313e, and third enclosure 313f provided on movable member 313. An urging force is generated by first attraction metal plate 321a, second attraction metal plate 321b, first magnet group 305a, and third magnet group 305c, as well as an urging force generated by third attraction metal plate 321c and magnet 312. These urging forces urge movable member 300b toward fixed member 302 via first rolling member 323a, second rolling member 323b, and third rolling member 323c. When the movable part 300b moves relative to the fixed part 300a, the first rolling member 323a, the second rolling member 323b, and the third rolling member 323c roll, so that almost no load is generated due to friction.

[0052] The first coil 319a is positioned to face the first magnet group 305a, the second coil 319b is positioned to face the second magnet group 305b, and the third coil 319c is positioned to face the third magnet group 305c, each of which constitutes a VCM (voice coil motor). The first coil 319a and the first magnet group 305a constitute a first actuator. Similarly, the second coil 319b and the second magnet group 305b constitute a second actuator 324b, and the third coil 319c and the third magnet group 305c constitute a third actuator. Here, the image sensor 301 is approximately rectangular, and the direction perpendicular to the short side of the optical axis orthogonal plane 401c is defined as the X direction, and the direction perpendicular to the long side is defined as the Y direction.

[0053] The first actuator is located along the short side in the X direction of the image sensor 301. The first magnet group 305a has a magnetic circuit configuration in which its magnetic force changes in the X direction, and the first actuator generates a driving force in the X direction depending on the direction of current flow through the first coil 319a. The second actuator and the third actuator are located side by side along the long side in the Y direction of the image sensor 301. The second magnet group 305b and the third magnet group 305c each have a magnetic circuit configuration in which their magnetic force changes in the Y direction. Depending on the direction of current flow through the second coil 319b and the third coil 319c, the second actuator and the third actuator generate a driving force in the Y direction. The second actuator and the third actuator are located approximately symmetrically in the X direction around the optical axis 401a, and generate a rotational force around the optical axis 401a depending on the difference in driving force between the second actuator and the third actuator.

[0054] Based on the amount of blur detected by the blur detection means 217b (amount of detected blur), the movable part 300b is driven in the X direction, the Y direction, and the rotation direction around the optical axis 401a so as to reduce (cancel) the blur using the method described above. This makes it possible to acquire an image with reduced blur.

[0055] In electronic front-curtain shooting mode, an image is generated by exposing the image sensor 301 to light passing through a slit between the reset scan (electronic front curtain) of the image sensor 301 and the rear blade group 5 mounted on the focal plane shutter 218 that tracks the electronic front curtain. When the shake detection means 217a of the imaging device 200 detects shake, the movable part 300b on which the image sensor 301 is mounted is driven to perform shake correction. Meanwhile, because the focal plane shutter 218 is fixed to a frame member (not shown), if the movable part 300b moves while the electronic front curtain is running, the width of the slit between the electronic front curtain and the rear blade group 5 that tracks the electronic front curtain changes. To obtain an image with appropriate exposure, it is important to maintain the width of the slit between the electronic front curtain and the rear blade group 5 that tracks the electronic front curtain. If the width of this slit changes, the amount of light exposed to the image sensor 301 changes, resulting in a deterioration in the exposure characteristics of the image.

[0056] For example, if movable unit 300b is controlled to move in the Y direction during shooting, the width of the slit between the electronic front curtain and the trailing blade group 5 that follows it will narrow or widen, resulting in an image that is darker or brighter than the appropriate exposure. Also, if movable unit 300b is controlled to move in a rotational direction around optical axis 401a during shooting, the electronic front curtain will tilt relative to the trailing blade group 5, resulting in an image with different brightness on the left and right.

[0057] Therefore, in the electronic front curtain shooting mode, it is important to control the image stabilization of the image stabilization mechanism 300 in accordance with the shutter speed during shooting so that the image is not affected even if the movable part 300b operates during the electronic front curtain travel.

[0058] In mechanical shutter shooting mode, the leading blade group 4 and the trailing blade group 5 travel together, forming a slit, and light passing through the slit exposes the image sensor 301 to create an image. When the blur detection means 217a of the imaging device 200 detects blur, the movable part 300b on which the image sensor 301 is mounted is driven to perform blur correction. However, because the focal plane shutter 218 is fixed to a frame member (not shown), the width of the slit formed by the leading blade group 4 and the trailing blade group 5 does not change when the movable part 300b on which the image sensor 301 is mounted is driven. To obtain an image with a proper exposure, it is important to maintain the width of the slit formed by the leading blade group 4 and the trailing blade group 5.

[0059] Next, we will explain the operation of the image stabilization mechanism 300 according to the shooting mode of the image capture device 200 in this embodiment. The image capture device 200 in this embodiment has two shooting modes: a mechanical shutter shooting mode (first mode) and an electronic front-curtain shooting mode (second mode).

[0060] (Mechanical shutter shooting mode) When the mechanical shutter shooting mode is selected as the shooting mode, the imaging device 200 executes the shake correction control (first shake correction) of the shake correction mechanism 300 regardless of the shutter time (shutter speed) set by the user.

[0061] In mechanical shutter shooting mode, leading blade group 4 and trailing blade group 5 mounted on focal plane shutter 218 travel forming a slit, and light passing through the slit exposes image sensor 301 to form an image. Therefore, the amount of light passing through the slit between leading blade group 4 and trailing blade group 5 does not change whether the first image sensor 301 is turned on or off. The amount of light exposing image sensor 301 changes depending on the movement speed of movable part 300b mounting image sensor 301. However, because the movement speed of movable part 300b is slower than the travel speed of the blade groups, the effect of driving image sensor 300 on image exposure is negligible. For this reason, in mechanical shutter shooting mode, no restrictions are placed on the operation of image sensor 300 (image sensor 300 performs image sensor shake correction control) regardless of the shutter speed setting.

[0062] (Electronic front curtain shooting mode) When the electronic front-curtain shooting mode is selected as the shooting mode, even if the user has set the shake correction control (first shake correction) of shake correction mechanism 300 to ON, if the shutter speed is faster than a predetermined time, drive of shake correction mechanism 300 is prohibited. That is, in this case, shooting is performed with first shake correction turned OFF. On the other hand, if the shutter speed is slower than the predetermined time, shooting is performed while executing the shake correction control of shake correction mechanism 300 (drive of shake correction mechanism 300 is permitted). For example, the predetermined shutter speed is 1 / 1000 second, but is not limited to this.

[0063] In electronic first-curtain shooting mode, as described above, an image is formed by exposing image sensor 301 to light that passes through the slit between the electronic first curtain and the trailing blade group 5 that follows it. When image stabilizer mechanism 300 is driven during shooting, image sensor 301 mounted on movable part 300b operates. Therefore, the amount of light that passes through the slit between the electronic first curtain and the trailing blade group 5 that follows it varies relative to the appropriate exposure amount, and the exposure within the image varies depending on the amount of drive of image stabilizer mechanism 300. Furthermore, the faster the shutter speed, the narrower the width of the slit between the electronic first curtain and the trailing blade group 5 that follows it. Therefore, the drive of movable part 300b changes the width of the slit between the electronic first curtain and the trailing blade group 5 that follows it, which has a significant impact on the exposure of the image, and an image with appropriate exposure may not be obtained.

[0064] If the shutter speed is faster than a predetermined time, the exposure time of image sensor 301 is short, so even if the operation of image stabilization mechanism 300 (first image stabilization) is turned off, there is little effect of camera shake on the image. Therefore, in this embodiment, to prevent a deterioration in the exposure characteristics of the image due to driving image stabilization mechanism 300, the image stabilization control (first image stabilization) of image stabilization mechanism 300 is turned off when the shutter speed is faster than a predetermined time.

[0065] On the other hand, when the shutter speed is slower than the specified time, the exposure time of image sensor 301 is long, so even if the light passing through the slit between the electronic front curtain and the trailing blade group 5 that follows it changes relative to the appropriate exposure amount, the impact on the exposure of the image is minor. Therefore, when the shutter speed is slow, there is no restriction on the operation of image blur correction mechanism 300 (image blur correction control of image blur correction mechanism 300 is executed).

[0066] As described above, the imaging device 200 of this embodiment includes an imaging element 301 that captures an image and a blur correction mechanism 300 that corrects blur by moving the imaging element 301 based on the amount of blur detected by the blur detection means 217a. The imaging device 200 also includes a shutter device (focal plane shutter 218) having the leading blade group 4 and the trailing blade group 5, and a control means (blur correction control means 216a) that controls blur correction of the blur correction mechanism. The imaging element 301 has a first mode (mechanical shutter shooting mode) and a second mode (electronic front-curtain shooting mode). The first mode is a mode in which an image is captured based on light passing through a region (slit) formed by the leading blade group 4 and the trailing blade group 5. The second mode is a mode in which an image is captured based on light passing through a region (slit) between the electronic front curtain and the trailing blade group 5 of the imaging element 301. The control means executes shake correction control in the first mode, and determines whether or not to execute shake correction control based on the shutter speed (shutter time) of the shutter device in the second mode.

[0067] Preferably, the imaging device 200 has a setting means (CPU 204) that sets the shutter speed. In the second mode, the control means does not execute shake correction control if the shutter speed set by the setting means is faster than a predetermined shutter speed. On the other hand, in the second mode, the control means executes shake correction control if the shutter speed is slower than the predetermined shutter speed. According to the imaging device 200 of this embodiment, it is possible to acquire an image by appropriately executing shake correction with an appropriate exposure. [Example]

[0068] Next, an imaging device according to a second embodiment of the present invention will be described. The imaging device of this embodiment differs from the imaging device of the first embodiment in that it has an electronic shutter mode (third mode) as a shooting mode in addition to the mechanical shutter shooting mode (first mode) and electronic front-curtain shooting mode (second mode) of the first embodiment. The operation (shake correction control) of the image stabilization mechanism 300 in the electronic shutter mode will be described below. Note that other configurations and operations of the imaging device of this embodiment are the same as those of the imaging device of the first embodiment, so descriptions thereof will be omitted.

[0069] (Electronic shutter mode) When electronic shutter mode is selected, CPU 204 of the imaging device executes shake correction control (first shake correction) of shake correction mechanism 300, regardless of the shutter time set by the user. That is, if the user sets first shake correction to ON, shooting is performed with first shake correction turned ON, and if the user sets first shake correction to OFF, shooting is performed with first shake correction turned OFF.

[0070] In electronic shutter mode, CPU 204 electrically controls the start and end of accumulation of electric charge generated by light incident on imaging surface 301a of image sensor 301. Therefore, the amount of exposure to image sensor 301 does not change when image sensor 301 is driven by image stabilization mechanism 300 during shooting; it changes only in accordance with the movement speed of movable part 300b on which image sensor 301 is mounted. Because the movement speed of movable part 300b is slower than the accumulation start and end scans of electric charge in image sensor 301, the effect of driving image stabilization mechanism 300 on image exposure is negligible. For this reason, in this embodiment, no restriction is placed on the drive of image stabilization mechanism 300 (image stabilization control of image stabilization mechanism 300 is performed) regardless of the shutter time setting in electronic shutter mode.

[0071] (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.

[0072] According to each embodiment, it is possible to provide an imaging device, a control method, and a program that can acquire an image by appropriately performing image blur correction with appropriate exposure.

[0073] 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]

[0074] 4. Leading feather group 5 Rear feather group 200 Imaging device 216a blur correction control means (control means) 217a Shake detection means 218 Focal plane shutter (shutter device) 300 Image stabilization mechanism 301 Image sensor

Claims

1. an image sensor for acquiring an image; a shake correction mechanism that corrects shake by moving the image sensor based on the amount of shake detected by a shake detection means; a shutter device; a control unit that controls the image stabilization of the image stabilization mechanism, the imaging device has a first mode in which the image is acquired based on light passing through an area between an electronic front curtain of the imaging element and a rear blade group of the shutter device, and a second mode in which the image is acquired by a method different from a method used in the first mode, the control means executes the image stabilization control in the first mode and the second mode when the shutter speed is slower than a predetermined shutter speed; an image pickup apparatus, characterized in that the control means does not perform the image stabilization control in the first mode and performs the image stabilization control in the second mode when the shutter speed is faster than the predetermined shutter speed.

2. the shutter device has a front blade group, 2. The imaging apparatus according to claim 1, wherein in the second mode, the image is acquired based on light passing through an area formed by the front blade group and the rear blade group.

3. 2. The imaging apparatus according to claim 1, wherein the second mode is an electronic shutter mode.

4. the image stabilization mechanism reduces image plane blur caused by translation and rotation by moving the image sensor, 4. The imaging device according to claim 1, wherein the control means does not execute the image stabilization control in the first mode when the shutter speed is faster than the predetermined shutter speed in order to suppress changes in exposure at the imaging element.

5. 5. The imaging apparatus according to claim 1, wherein the electronic front curtain performs scanning to start charge accumulation in the imaging element before the rear blade group starts to travel.

6. an image sensor for acquiring an image; a blur correction mechanism including a fixed section and a movable section movable relative to the fixed section, the blur correction mechanism reducing image plane blur due to translation and rotation by moving the image sensor held by the movable section based on the amount of blur detected by a blur detection means; a shutter device; a control unit that controls the image stabilization of the image stabilization mechanism, the imaging device has a first mode in which the image is acquired based on light passing through a region between an electronic front curtain of the imaging element and a rear blade group of the shutter device, and a second mode in which the image is acquired by a method different from a method used in the first mode, the control means executes the image stabilization control in the first mode and the second mode when the shutter speed is slower than a predetermined shutter speed; an image capturing apparatus, characterized in that, when the shutter speed is faster than the predetermined shutter speed, the control means does not perform the image stabilization control in the first mode in order to suppress a change in exposure at the image sensor, and performs the image stabilization control in the second mode.

7. 7. The imaging apparatus according to claim 6, wherein the electronic front curtain performs scanning to start charge accumulation in the imaging element before the rear blade group starts to travel.

8. 8. The imaging apparatus according to claim 6, wherein the second mode is an electronic shutter mode.

9. an image sensor for acquiring an image; a blur correction mechanism including a fixed section and a movable section movable relative to the fixed section, the blur correction mechanism reducing image plane blur by moving the image sensor held by the movable section based on the amount of blur detected by a blur detection means; a shutter device; a control unit that controls the image stabilization of the image stabilization mechanism, the imaging device has a first mode in which the image is acquired based on light passing through a region between an electronic front curtain of the imaging element and a rear blade group of the shutter device, and a second mode in which the image is acquired by a method different from a method used in the first mode, when a shutter speed is faster than a predetermined shutter speed, the control unit limits the image stabilization control in the first mode more than the image stabilization control in the second mode; wherein the control unit does not limit the image blur correction control in either the first mode or the second mode when the shutter speed is slower than the predetermined shutter speed, and limits the image blur correction control in the first mode and does not limit the image blur correction control in the second mode when the shutter speed is faster than the predetermined shutter speed.

10. the shutter device has a front blade group, 10. The imaging apparatus according to claim 9, wherein in the second mode, the image is acquired based on light passing through an area formed by the front blade group and the rear blade group.

11. 10. The imaging apparatus according to claim 9, wherein the second mode is an electronic shutter mode.

12. The image stabilization mechanism reduces image plane blur caused by translation and rotation, 12. The imaging device according to claim 9, wherein the control unit limits the image stabilization control in the first mode to suppress changes in exposure at the imaging element when the shutter speed is faster than the predetermined shutter speed.

13. 13. The imaging apparatus according to claim 9, wherein the electronic front curtain starts scanning to start charge accumulation in the imaging element before the rear blade group starts traveling.

14. an acquisition step of acquiring an image using an imaging element; a shake correction step of performing shake correction control of a shake correction mechanism based on the amount of shake detected by the shake detection means and correcting shake by moving the image pickup element, a first mode in which the image is acquired based on light passing through an area between an electronic front curtain of the image sensor and a rear blade group of a shutter device, and a second mode in which the image is acquired by a method different from that used in the first mode, If the shutter speed is slower than a predetermined shutter speed in the blur correction step, the blur correction control is performed in the first mode and the second mode; a control method for an imaging apparatus, characterized in that, if the shutter speed is faster than the predetermined shutter speed in the image blur correction step, the image blur correction control is not performed in the first mode, and the image blur correction control is performed in the second mode.

15. an acquisition step of acquiring an image using an imaging element; a blur correction step of performing blur correction control of a blur correction mechanism based on the amount of blur detected by the blur detection means and moving the imaging element to reduce image plane blur due to translation and rotation. a first mode in which the image is acquired based on light passing through an area between an electronic front curtain of the image sensor and a rear blade group of a shutter device, and a second mode in which the image is acquired by a method different from that used in the first mode, If the shutter speed is slower than a predetermined shutter speed in the blur correction step, the blur correction control is performed in the first mode and the second mode; a control method for an imaging apparatus, characterized in that, when the shutter speed is faster than the predetermined shutter speed in the image blur correction step, the image blur correction control is not performed in the first mode to suppress a change in exposure at the image sensor, and the image blur correction control is performed in the second mode.

16. an acquisition step of acquiring an image using an imaging element; a blur correction step of performing blur correction control of a blur correction mechanism based on the amount of blur detected by the blur detection means and correcting image plane blur by moving the image sensor, a first mode in which the image is acquired based on light passing through an area between an electronic front curtain of the image sensor and a rear blade group of a shutter device, and a second mode in which the image is acquired by a method different from that used in the first mode, In the blur correction step, when a shutter speed is faster than a predetermined shutter speed, the blur correction control in the first mode is limited more than the blur correction control in the second mode; a control method for an imaging apparatus, wherein, in the image blur correction step, if the shutter speed is slower than the predetermined shutter speed, the image blur correction control is not limited in either the first mode or the second mode, and if the shutter speed is faster than the predetermined shutter speed, the image blur correction control is limited in the first mode and is not limited in the second mode.

17. 17. A program causing a computer to execute the method for controlling an imaging apparatus according to claim 14.

Images