Lens device and imaging apparatus

Abstract

This lens device comprises: a lens; a lens holder that holds the lens and is movable in the optical axis direction of the lens; and a linear actuator that moves the lens holder. The linear actuator includes a plurality of magnets that are disposed along the optical axis direction, and two-phase movable coils that are attached to the lens holder, face the magnets in a facing direction orthogonal to the optical axis direction, and are disposed side by side in the optical axis direction with a phase shift of 90±45 degrees in electrical angle. At least one of the two-phase movable coils includes a pair of flat portions extending in a width direction orthogonal to the optical axis direction and the facing direction, and a pair of bent portions each connecting both ends of the pair of flat portions and bent in the facing direction. The bent portions are disposed at positions not overlapping the magnets in the facing direction.

Description

Lens apparatus and imaging apparatus

[0001] The present technology relates to the technical field of lens apparatuses and imaging apparatuses.

[0002] Conventionally, in a linear motor that moves a lens of an imaging apparatus, a pair of movable coils formed in a substantially elliptical shape are arranged so as not to overlap in the moving direction of the lens (see, for example, Patent Document 1).

[0003] Japanese Unexamined Patent Publication No. 2019-213433

[0004] In the above-described linear motor, since an opening is provided in the central portion of the movable coil, the linear motor becomes elongated in the moving direction of the movable coil, resulting in an increase in size of the entire apparatus. In addition, in the above-described linear motor, the number of magnets arranged opposite to the movable coil also increases, which leads to an increase in weight. Therefore, the above-described linear motor has a problem that the thrust efficiency in terms of weight ratio and volume ratio is low.

[0005] Therefore, an object of the present technology is to improve thrust efficiency while achieving size reduction.

[0006] A lens apparatus according to the present technology includes: a lens; a lens holder that holds the lens and is movable in an optical axis direction of the lens; and a linear actuator that moves the lens holder. The linear actuator includes: a plurality of magnets arranged along the optical axis direction; and two-phase movable coils attached to the lens holder, facing the magnets in a facing direction orthogonal to the optical axis direction, arranged in the optical axis direction with a phase shift of 90 degrees ±45 degrees in electrical angle. At least one of the two-phase movable coils includes: a pair of flat portions extending in a width direction orthogonal to the optical axis direction and the facing direction; and a pair of bent portions respectively connecting both ends of the pair of flat portions and bending in the facing direction. The bent portions are arranged at positions that do not overlap the magnets in the facing direction.

[0007] This is a diagram showing the configuration of an imaging device as an embodiment of the present technology. This is a diagram showing the configuration of a mechanism unit. This is a cross-sectional view of a mechanism unit including a linear actuator, perpendicular to the optical axis direction. This is a view of the linear actuator from the width direction. This is a view of the linear actuator with the second yoke removed from the opposite direction. This is a perspective view of the movable coil. This is a diagram showing the relationship between the magnet and the gap. This is a diagram showing a comparison of the aspect ratios of linear actuators. This is a diagram showing the change in weight when the aspect ratio of the linear actuator is changed. This is a diagram showing the functional configuration of the imaging device. This is a diagram showing the configuration of a movable coil in another embodiment. This is a diagram showing the configuration of a movable coil in another embodiment. This is a diagram showing a lens device equipped with a movable coil. This is a diagram showing the configuration of a linear actuator in another embodiment. This is a diagram showing the configuration of a linear actuator in another embodiment. This is a diagram showing the configuration of a linear actuator in another embodiment. This is a diagram showing the configuration of a linear actuator in another embodiment. This is a diagram showing the configuration of a linear actuator in another embodiment. This is a diagram showing the configuration of a linear actuator in another embodiment. This is a diagram showing the configuration of a linear actuator in another embodiment.

[0008] The embodiments will be described below in the following order: <1. Configuration of the imaging device> <2. Other embodiments> <3. Summary> <4. This technology>

[0009] <1. Configuration of the Imaging Device> Figure 1 is a diagram showing the configuration of an imaging device 1 as an embodiment of the present technology. As shown in Figure 1, the imaging device 1 comprises a camera housing 2 with the necessary parts arranged inside and outside, and a lens device 3 attached to the front part 2a of the camera housing 2. Although the imaging device 1 is shown as an example with an interchangeable lens device 3, it is not limited to this, and may be a lens-integrated type in which the camera housing 2 and the lens device 3 are integrally configured.

[0010] The camera housing 2 has, for example, multiple operating parts 11 arranged on its top and rear surfaces. The operating parts 11 include various types such as buttons, dials, and pressable and rotatable composite operating elements. In the imaging device 1, by operating the operating parts 11, it is possible to perform operations such as shutter operation, menu operation, playback operation, mode selection / switching operation, focus operation, zoom operation, and parameter selection / setting such as shutter speed and F-number.

[0011] A rear monitor (not shown) is located on the rear surface 2b of the camera housing 2. The rear monitor displays through-view images, recorded images, and other information.

[0012] A circular opening 2c is formed in the front portion 2a of the camera housing 2. A mount portion 12 for attaching the lens device 3 is provided around the opening 2c. The mount portion 12 has an annular coupling ring 12a and an arc-shaped mount engagement portion 12b that protrudes inward from the coupling ring 12a. For example, three mount engagement portions 12b are provided spaced apart in the circumferential direction.

[0013] Inside the camera housing 2, an image sensor 13, such as a CCD (Charge Coupled Device) or CMOS (Complementary Metal-Oxide Semiconductor), is arranged. The image sensor 13 is located behind the aperture 2c.

[0014] An arc-shaped contact portion 14 is positioned at the lower end of the inside of the mounting portion 12.

[0015] The lens device 3 is detachably attached to the camera housing 2, and the necessary parts are arranged inside and outside the outer cylinder 21.

[0016] Multiple adjustment rings 22 are rotatably supported on the outer surface of the outer cylinder 21, arranged in a front-to-back configuration. The adjustment rings 22 have functions such as adjusting focus, zoom, and aperture light intensity.

[0017] Inside the outer cylinder 21, multiple lens groups 23 are arranged spaced apart in the optical axis direction (front-to-back direction). Each lens group 23 has at least one lens. An example of a lens group 23 is one that includes a front lens 23a located at the very front and another lens located behind the front lens 23a.

[0018] A lens mount 24 is attached to the rear end of the outer cylinder 21. The lens mount 24 is provided with outwardly protruding engagement projections 24a. For example, there are three engagement projections 24a spaced apart in the circumferential direction. A connection terminal (not shown) is provided on the rear end surface of the lens mount 24.

[0019] The lens device 3 is attached to the camera housing 2 by connecting the lens mount 24 to the mount portion 12. The lens device 3 can be attached to the camera housing 2 by rotating the entire lens device 3 in one direction around the optical axis relative to the camera housing 2.

[0020] When the lens device 3 is mounted on the camera housing 2, a connection terminal (not shown) is connected to the contact portion 14 of the camera housing 2. This enables the exchange of signals and the supply of power between the camera housing 2 and the lens device 3.

[0021] The lens device 3 can be removed from the camera housing 2 by rotating the entire lens device 3 in the opposite direction around the optical axis relative to the camera housing 2 and pulling it away from the camera housing 2.

[0022] Figure 2 shows the configuration of the mechanism unit 31. The mechanism unit 31 is located inside the lens device 3. As shown in Figure 2, the mechanism unit 31 has the necessary parts arranged or supported in the inner cylinder 32. In the lens device 3, the inner cylinder 32 may be integrally provided with the outer cylinder 21 as part of the outer cylinder 21.

[0023] The inner cylinder 32 is made of a non-magnetic material such as resin or a magnetic material, and has a cylindrical main body portion 33 whose optical axis direction (front-to-back direction) is oriented axially, and an inner flange portion 34 that protrudes inward from the rear end of the main body portion 33.

[0024] Two first support portions 35, which protrude inward, are provided at the rear end of the main body portion 33, spaced, for example, 180 degrees apart in the circumferential direction of the main body portion 33.

[0025] A disc-shaped cover portion 36, made of a non-magnetic material such as resin or a magnetic material, is attached to the front end of the main body portion 33, with the optical axis direction oriented axially. A through hole is formed in the center of the cover portion 36. In addition, two second support portions 37, which protrude rearward, are provided at the rear end of the cover portion 36, spaced 180 degrees apart in the circumferential direction of the cover portion 36.

[0026] The first support portion 35 and the second support portion 37 face each other in the optical axis direction when the lid portion 36 is attached to the inner cylinder 32.

[0027] Two guide shafts 38 are spanned across the inner flange portion 34 and the cover portion 36 along the optical axis direction. The two guide shafts 38 are arranged, for example, 180 degrees apart in the circumferential direction of the inner cylinder 32, and are positioned at different locations in the circumferential direction of the inner cylinder 32 from the first support portion 35 and the second support portion 37.

[0028] A lens holder 39 and a lens 23b, which are provided as movable parts on the guide axis 38, are supported so as to be movable in the direction of the optical axis. The lens 23b is one of the lens group 23 and is held by the lens holder 39. The lens 23b functions, for example, as a focusing lens or a zoom lens.

[0029] The lens holder 39 has a lens holding portion 40, a supported portion 41, a coil mounting portion 42, and a mounting projection 43.

[0030] The lens holder portion 40 is formed in a frame shape and holds the lens 23b. The lens 23b is attached to the lens holder portion 40 by adhesive, press-fitting, or the like.

[0031] The supported portion 41 protrudes outward from the lens holding portion 40. Two supported portions 41 are provided spaced apart in the circumferential direction of the inner cylinder 32, and each is slidably supported on the guide shaft 38. Therefore, the lens holder 39 and the lens 23b are guided together by the guide shaft 38 and moved in the direction of the optical axis.

[0032] The coil mounting portion 42 protrudes outward from the lens holding portion 40. Two coil mounting portions 42 are provided spaced apart in the circumferential direction of the inner cylinder 32, and a movable coil 54 is attached to each by adhesive or the like. Therefore, when current is supplied to the movable coil 54 and the movable coil 54 moves in the optical axis direction relative to the magnet 53, the lens holder 39 and the lens 23b move in the optical axis direction along with the movable coil 54. Then, by moving the lens 23b in the optical axis direction, for example, focus adjustment or zoom adjustment is performed.

[0033] The mounting projection 43 protrudes outward from the lens holding portion 40. A detection bar 44 extending in the direction of the optical axis is attached to the mounting projection 43. The detection bar 44 moves in the direction of the optical axis along with the lens holder 39.

[0034] A detector 45 is mounted on the inner circumferential surface of the main body portion 33 of the inner cylinder 32 at a position opposite to the detection bar 44. The detector 45 detects the position of the detection bar 44 when the lens holder 39 moves, and by detecting the position of the detection bar 44, the position of the lens 23b in the optical axis direction or the amount of movement in the optical axis direction is detected.

[0035] A linear actuator 50 is positioned between the first support portion 35 and the second support portion 37, which are arranged opposite each other in the optical axis direction. The linear actuator 50 comprises a first yoke 51, a second yoke 52, a magnet 53, and a pair of movable coils 54a and 54b. In the following description, when the movable coils 54a and 54b are not distinguished, they will be referred to as movable coil 54. The linear actuator 50 may be positioned as a single unit or as three or more units relative to the lens holder 39.

[0036] Figure 3 is a cross-sectional view of the mechanism unit including the linear actuator 50, perpendicular to the optical axis direction. For the sake of clarity, only the inner cylinder 32, the first yoke 51, and the second yoke 52 are shown in cross-section in Figure 3. Figure 4 is a view of the linear actuator 50 from the width direction. For the sake of clarity, the first yoke 51, the second yoke 52, and the magnet 53 are hatched in Figure 4. Figure 5 is a view of the linear actuator 50 with the second yoke 52 removed, viewed from the opposite direction. In Figure 5, all angular dimensions refer to electrical angles.

[0037] In the following, the direction perpendicular to the optical axis and in which the magnet 53 and the movable coil 54 face each other will be described as the opposing direction. The opposing direction coincides with the coil axis direction of the movable coil 54. Furthermore, the direction perpendicular to the optical axis and the opposing direction will be described as the width direction. The width direction coincides with the longitudinal direction of the magnet 53 and the movable coil 54.

[0038] As shown in Figures 2 to 5, the first yoke 51 is a plate made of a magnetic metal material that extends in the optical axis direction and the width direction. Depending on the driving distance of the lens holder 39, the length of the first yoke 51 in the optical axis direction is often longer than the length in the width direction.

[0039] The second yoke 52 is a plate made of magnetic metal material, with its central portion extending in the optical axis direction and width direction, and both ends in the optical axis direction bent at a 90-degree angle toward the inside of the inner cylinder 32. The first yoke 51 is joined to both ends of the second yoke 52. Therefore, when the first yoke 51 and the second yoke 52 are combined, they form a roughly hollow rectangular prism that penetrates in the width direction. Alternatively, the linear actuator 50 may be configured without the second yoke 52, for example, by sandwiching the movable coil 54 between two flat plates like the first yoke 51 and maintaining the gap with resin or the like.

[0040] Multiple magnets 53 are arranged in a row along the optical axis direction on the inner surface of the first yoke 51 on the side facing the second yoke 52. The magnets 53 placed on the first yoke 51 are attracted to the first yoke 51 by magnetic force.

[0041] On the inner surface of the second yoke 52 on the first yoke 51 side, a plurality of magnets 53 are arranged side by side along the optical axis direction. The magnet 53 disposed on the second yoke 52 is attracted to the second yoke 52 by magnetic force.

[0042] The magnet 53 attracted to the first yoke 51 and the magnet 53 attracted to the second yoke 52 are arranged to be spaced apart by a predetermined distance in the opposing direction. A moving coil 54 is disposed between the magnet 53 attracted to the first yoke 51 and the magnet 53 attracted to the second yoke 52.

[0043] The magnets 53 arranged side by side in the optical axis direction are spaced apart from each other. Further, the magnet 53 attracted to the first yoke 51 and the magnet 53 attracted to the second yoke 52 are arranged so as to face each other in the opposing direction, respectively.

[0044] Furthermore, the magnets 53 arranged side by side in the optical axis direction are arranged such that N poles and S poles alternately face toward the moving coil 54 side. In addition, among the magnets 53 arranged facing each other in the opposing direction, different magnetic poles are arranged to face the moving coil 54. Therefore, the magnets 53 arranged facing each other in the opposing direction generate an attractive force that attracts each other.

[0045] The length of the magnet 53 in the width direction is longer than the lengths in the optical axis direction and the opposing direction. Further, the length of the magnet 53 in the width direction is substantially the same as the length of the first yoke 51 and the second yoke 52 in the width direction.

[0046] Fig. 6 is a perspective view of moving coils 54a and 54b. As shown in Figs. 2 to 6, the moving coil 54a constitutes a first phase, and the moving coil 54b constitutes a second phase. In the present embodiment, the moving coil 54a and the moving coil 54b are formed in the same shape, and the moving coil 54b is arranged reversed with respect to the moving coil 54a.

[0047] The moving coil 54 is formed by winding a wire in a loop. The moving coil 54 has a pair of flat portions 61 extending along the width direction across the coil opening, and a pair of bent portions 62 respectively connecting the ends of the pair of flat portions 61.

[0048] The length of the flat portion 61 in the width direction is not less than the length of the magnet 53 in the width direction. Therefore, it can also be said that the length of the flat portion 61 in the width direction is not less than the length of the first yoke 51 and the second yoke 52 in the width direction.

[0049] The flat portion 61 is disposed so as to face the magnet 53 over the entire region in the width direction. In other words, both ends of the flat portion 61 are located outside both ends of the magnet 53 in the width direction, with reference to the center of the magnet 53 in the width direction.

[0050] The winding width of the flat portion 61 in the optical axis direction is approximately 90 degrees in electrical angle. Further, the width of the coil opening in the moving coil 54 in the optical axis direction is approximately 90 degrees in electrical angle. Therefore, the moving coil 54 has a length of approximately 270 degrees in electrical angle in the optical axis direction.

[0051] Incidentally, since the coil opening portion of the moving coil 54 does not generate thrust, it is structurally a wasted space. It is also possible to form a moving coil by winding a wire such that no coil opening is formed, but even in that case, the thrust is less likely to be increased compared to a moving coil having a coil opening, and the effect is limited.

[0052] Therefore, the linear actuator 50 has a structure in which the flat portion 61 of the moving coil 54b is disposed in the coil opening of the moving coil 54a, and the flat portion 61 of the moving coil 54a is disposed in the coil opening of the moving coil 54b.

[0053] Specifically, in the linear actuator 50, the movable coil 54b is positioned with an electrical angle offset of 90 degrees ± 45 degrees relative to the movable coil 54a. More preferably, the movable coil 54 is positioned with an electrical angle offset of 90 degrees ± 20 degrees relative to the movable coil 54a. In other words, the two-phase movable coils 54a and 54b are positioned so as to be aligned in the optical axis direction with a phase difference of 90 degrees ± 45 degrees in electrical angle. Therefore, the movable coils 54a and 54b can be positioned together within a range of approximately 360 degrees in electrical angle.

[0054] As a result, the flat portions 61 of the movable coils 54a and 54b are arranged almost without gaps in the direction of the optical axis, so that only the portion with high magnetic flux density can be used efficiently.

[0055] Furthermore, the movable coil 54 can have a shorter length in the optical axis direction compared to when two movable coils are placed side by side without overlapping in the optical axis direction. Also, since the movable coils 54a and 54b are shorter in the optical axis direction, the number of magnets 53 that need to be placed in the optical axis direction can be reduced, and the linear actuator 50 as a whole can be made shorter in the optical axis direction and miniaturized. As a result, the linear actuator 50 can improve the thrust efficiency in terms of both weight ratio and volume ratio.

[0056] In this case, if the two movable coils are formed flat all around, and the flat portion of one movable coil is placed in the coil opening of the other movable coil, the movable coils will interfere with each other.

[0057] Therefore, the movable coil 54 has a bent portion 62. The bent portion 62 is formed so that at least a part of it is bent in a direction opposite to the plane through which the flat portion 61 extends, that is, the plane passing through the optical axis direction and the width direction.

[0058] Specifically, the bent portion 62 of the movable coil 54 has a connecting portion 62a and a flat portion 62b. The connecting portion 62a is connected to the end of the flat portion 61 and also to the end of the flat portion 62b.

[0059] The connecting portion 62a extends from the end of the flat portion 61 so as to be inclined in a direction opposite to the width direction. The flat portion 62b extends parallel to the flat portion 61, that is, in a plane passing through the optical axis direction and the width direction. In this case, the connecting portion 62a is inclined such that the flat portion 61 and the flat portion 62b are offset by more than half the thickness of the flat portion 62b in the opposing direction.

[0060] The bent portion 62 of the movable coil 54a is bent in a direction toward the radially inward side of the inner cylinder 32. The bent portion 62 of the movable coil 54b is bent in a direction toward the radially outward side of the inner cylinder 32.

[0061] This prevents the bent portions 62 from interfering with each other when the movable coils 54a and 54b overlap.

[0062] As described above, since the flat portion 61 is positioned to face the magnet 53 across its entire width, the bent portion 62 is positioned so as not to overlap with the magnet 53 in the opposing direction. In other words, the bent portion 62 is located outside the width direction of both ends of the magnet 53, with reference to the center of the magnet 53 in the width direction.

[0063] However, since the length of the bent portion 62 in the winding direction is shorter than that of the flat portion 61, the thrust generated by the bent portion 62 is smaller than that of the flat portion 61. On the other hand, since the bent portion 62 does not overlap with the magnet 53 in the width direction and the opposing direction, it is possible to position the magnet 53 closer to the flat portion 61 than to the bent portion 62 in the opposing direction.

[0064] Therefore, the magnet 53 attached to the first yoke 51 and the magnet 53 attached to the second yoke 52 are positioned so as to be separated in opposing directions by the minimum distance that the flat portion 61 of the movable coil 54 can interpose.

[0065] As a result, the linear actuator 50 can generate a higher thrust in the flat section 61 compared to the case where the two movable coils are arranged side by side without overlapping in the optical axis direction, and thus can generate a higher thrust overall.

[0066] The movable coil 54 is attached to the coil mounting portion 42 at the bent portion 62. This does not affect the distance between the magnet 53 and the flat portion 61 in the opposing direction.

[0067] Furthermore, the end 63 of the winding that forms the movable coil 54 is pulled out from the bent portion 62. This prevents any influence on the distance between the magnet 53 and the flat portion 61 in the opposing direction when the end 63 is pulled out.

[0068] Figure 7 shows the relationship between the magnet 53 and the gap. As mentioned above, the magnets 53 are spaced apart in the optical axis direction. If the width of the magnet 53 in the optical axis direction is W1, and the distance between adjacent magnets 53 in the optical axis direction is W2 (see Figure 4), then the proportion of magnets 53 present in the optical axis direction in the linear actuator 50 can be expressed as W1 / (W1+W2). Hereafter, the proportion of magnets 53 present in the optical axis direction in the linear actuator 50 will be referred to as the magnet ratio.

[0069] Figure 7 shows the thrust multiplier, thrust fluctuation, weight, and the value obtained by dividing the thrust multiplier by the weight when the magnet ratio is changed in increments of 0.1 from 0.5 to 0.9. The thrust multiplier represents the thrust generated when a current of 1A is passed through the movable coil 54. The thrust fluctuation indicates the degree of thrust fluctuation in the optical axis direction. The weight represents the total weight of the magnets 53.

[0070] As can be seen from Figure 7, the total weight of the magnets 53 increases as the proportion of magnets increases. This is because the magnets 53 are arranged more densely as the proportion of magnets increases.

[0071] On the other hand, the thrust multiplier is maximum when the magnet ratio is around 0.7 and decreases as it moves away from 0.7. Also, the thrust fluctuation is minimum when the magnet ratio is around 0.7 and increases as it moves away from 0.7. Furthermore, the value obtained by dividing the thrust multiplier by the weight is also maximum when the magnet ratio is around 0.7 and decreases as it moves away from 0.7. This is because the flat portion 61 of the movable coil 54 exists only in the area of ​​high magnetic flux density, so it is greatly affected when the magnetic flux density distribution is distorted from a sine wave. By setting the magnet ratio to around 0.7, it is possible to increase the thrust efficiency relative to the weight while reducing the decrease in thrust. Ideally, the magnet ratio should be in the range of 0.6 to 0.8.

[0072] Figure 8 shows a comparison of the aspect ratios of the linear actuator 50. Figure 9 shows the change in weight when the aspect ratio of the linear actuator 50 is changed.

[0073] Here, the length of the linear actuator 50 in the opposing direction is denoted as vertical X, and the length of the magnet 53 in the width direction is denoted as horizontal Y (see Figure 3). Figure 8 shows the weight and performance ratio of the linear actuator 50 required to generate the same thrust when the aspect ratio (X:Y) is changed from 1:1 to 1:4 while keeping vertical X constant. Figure 9 shows a graph of the weight of the linear actuator 50 required to generate the same thrust when the aspect ratio (X:Y) is changed from 1:1 to 1:4 while keeping vertical X constant. The performance ratio represents the ratio of the weight for each aspect ratio to the weight when the aspect ratio is 1:3.5.

[0074] As shown in Figures 8 and 9, the weight of the linear actuator 50 required to generate the same thrust tends to decrease as the aspect ratio increases. When the aspect ratio is 2.0 or greater, the weight of the linear actuator 50 required to generate the same thrust becomes less than 40g and does not change much. Similarly, the performance ratio also becomes 85% or greater when the aspect ratio is 2.0 or greater and does not change much.

[0075] Therefore, if the aspect ratio is less than 1:2, the weight required to generate the same thrust increases significantly, but if the aspect ratio is 1:2 or greater, it does not change much, which is preferable. Accordingly, the linear actuator 50 is configured such that each part has an aspect ratio of 2 or greater.

[0076] Next, we will describe an example of the functional configuration of the imaging device 1. Figure 10 is a diagram showing the functional configuration of the imaging device 1.

[0077] As shown in Figure 10, the imaging device 1 is equipped with an optical system 90 that guides light to the image sensor 98, and includes a camera signal processing unit 91 that performs signal processing such as analog-to-digital conversion of the captured image signal, and an image processing unit 92 that performs recording and playback processing of the image signal. The imaging device 1 also includes a display unit 93 that displays captured images, a R / W (reader / writer) 94 that writes and reads image signals to and from the memory 99, a CPU (Central Processing Unit) 95 that controls the entire imaging device 1, a lens drive control unit 96 that controls the driving of the lens including the optical system 90, and an operation unit 97 with various switches and other controls that the user can use to perform the operations they require.

[0078] The optical system 90 is, for example, a lens device 3.

[0079] The imaging device 1 is equipped with an image sensor 98, such as a CCD or CMOS, which converts the optical image captured by the optical system 90 into an electrical signal. The image sensor 98 is the same as the image sensor 13 described above.

[0080] The camera signal processing unit 91 performs various signal processing on the output signal from the image sensor 98, including conversion to a digital signal, noise reduction, image quality correction, and conversion to luminance and chromatic difference signals.

[0081] The image processing unit 92 performs compression encoding, decompression and decoding of image signals based on a predetermined image data format, as well as conversion processing of data specifications such as resolution.

[0082] The display unit 93 has the function of displaying various data such as the user's operation status to the operation unit 97 and the captured images. Note that the imaging device 1 does not necessarily have to have a display unit 93; the captured image data may be sent to another display device for display.

[0083] The R / W 94 writes image data encoded by the image processing unit 92 to the memory 99 and reads image data recorded in the memory 99.

[0084] The CPU 95 functions as a control processing unit that controls each circuit block provided in the imaging device 1, and controls each circuit block based on instruction input signals from the operation unit 97, etc.

[0085] The lens drive control unit 96 controls the drive source that moves the lens based on the control signal from the CPU 95. For example, the lens drive control unit 96 sends current to the movable coil 54 of the linear actuator 50 to move the lens holder 39 and the lens 23b in the optical axis direction.

[0086] The operation unit 97 outputs an instruction input signal to the CPU 95 in response to user operations. The operation unit 97 is the operation unit 11 described above.

[0087] The memory 99 is, for example, a semiconductor memory that can be attached to or detached from a slot connected to the R / W 94, or a semiconductor memory that is pre-built inside the imaging device 1.

[0088] The operation of the imaging device 1 is described below.

[0089] In the standby state for shooting, under the control of the CPU 95, the captured image signal is output to the display unit 93 via the camera signal processing unit 91 and displayed as a camera-through image. Also, when an instruction input signal is received from the operation unit 97, the CPU 95 outputs a control signal to the lens drive control unit 96, and the lens is moved based on the control of the lens drive control unit 96.

[0090] When a shooting operation is performed in response to an instruction input signal from the control unit 97, the captured image signal is output from the camera signal processing unit 91 to the image processing unit 92, where it is compressed and encoded, and converted into digital data in a predetermined data format. The converted data is output to the R / W 94 and written to the memory 99.

[0091] When playing back image data recorded in memory 99, in response to an operation on the operation unit 97, the R / W 94 reads out predetermined image data from memory 99, the image processing unit 92 performs decompression and decoding processing, and then the playback image signal is output to the display unit 93 and the playback image is displayed.

[0092] In this embodiment, "imaging" refers to a series of processes, some or all of which include the following: photoelectric conversion processing, which converts the light captured by the image sensor 98 into an electrical signal; processing by the camera signal processing unit 91, which converts the output signal from the image sensor 98 into a digital signal, removes noise, corrects image quality, and converts it into brightness and color difference signals; compression encoding, decompression and decoding of the image signal based on a predetermined image data format by the image processing unit 92, and conversion of data specifications such as resolution; and writing the image signal to the memory 99 by the R / W 94.

[0093] In other words, "imaging" may refer only to the photoelectric conversion process that converts the light captured by the image sensor 98 into an electrical signal, or it may refer to the process from the photoelectric conversion process that converts the light captured by the image sensor 98 into an electrical signal to the conversion of the output signal from the image sensor 98 into a digital signal by the camera signal processing unit 91, noise reduction, image quality correction, conversion to brightness and color difference signals, etc., and then the image processing unit 92 This may refer to the compression coding, decompression and decoding processing of image signals based on a predetermined image data format, as well as the conversion processing of data specifications such as resolution. It may also refer to the photoelectric conversion processing that converts the light captured by the image sensor 98 into an electrical signal, the conversion of the output signal from the image sensor 98 to a digital signal by the camera signal processing unit 91, noise reduction, image quality correction, conversion to brightness and color difference signals, and the compression coding, decompression and decoding processing of image signals based on a predetermined image data format, as well as the conversion processing of data specifications such as resolution by the image processing unit 92. It may also refer to the writing of the image signal to the memory 99 by the R / W 94.

[0094] <2. Other Embodiments> The embodiments are not limited to the specific examples described above, and various modified configurations are possible. Below, an example of a modified configuration will be described as another embodiment. It is also possible to combine the other embodiments described below, and it is also possible to combine one or more of the other embodiments described below with the embodiment described above.

[0095] [2.1. First movable coil in another embodiment] Figure 11 shows the configuration of movable coils 201a and 201b in another embodiment. In the linear actuator 50, movable coils 201a and 201b can be used instead of the movable coils 54a and 54b described above. In the following, components identical to those in the above embodiment are denoted by the same reference numerals and their descriptions are omitted.

[0096] The movable coils 201a and 201b each comprise a pair of flat sections 61 and a pair of bent sections 202. The bent sections 202 connect the ends of the pair of flat sections 61, respectively. The bent sections 202 extend from the ends of the flat sections 61 so as to be inclined in a direction opposite to the width direction.

[0097] Thus, even if the shape of the bent portion 202 of the movable coils 201a and 201b differs from that of the movable coils 54a and 54b, it is possible to miniaturize them in the same way as the movable coils 54a and 54b, and to increase the thrust efficiency.

[0098] [2.2. Second movable coil in another embodiment] Figure 12 shows the configuration of movable coils 211a and 211b in another embodiment. In the linear actuator 50, movable coils 211a and 211b can be used instead of the movable coils 54a and 54b described above.

[0099] As shown in Figure 12, the movable coil 211a comprises a pair of flat sections 61 and a pair of bent sections 212. The bent sections 212 connect the ends of the pair of flat sections 61, respectively. The bent sections 212 have a connecting section 212a and a flat section 212b. The connecting section 212a connects to the end of the flat section 61 and also to the end of the flat section 212b.

[0100] The connecting portion 212a extends from the end of the flat portion 61 so as to be inclined in a direction opposite to the width direction. The flat portion 212b extends parallel to the flat portion 61, that is, parallel to a plane passing through the optical axis direction and the width direction. At this time, the connecting portion 212a is inclined such that the flat portion 212b is offset in the opposite direction by more than the thickness of the flat portion 61.

[0101] The movable coil 211b is formed flat so as a whole that it aligns with a plane passing through the optical axis direction and the width direction.

[0102] Thus, even if at least one of the two-phase movable coils 211a and 211b, the movable coil 211a, has a flat portion 61a and a bent portion 212, and the other movable coil 211b is formed entirely flat, it is possible to miniaturize it and improve thrust efficiency, similar to the movable coil 54.

[0103] Figure 13 shows a mechanism unit 31 equipped with movable coils 211a and 211b. In the mechanism unit 31 equipped with movable coils 211a and 211b, the bent portion 212 of the movable coil 211a is positioned closer to the center than the flat portion 61.

[0104] By arranging them in this way, the diameter of the inner cylinder 32 can be reduced, and the lens device 3 can be made smaller.

[0105] [2.3. First Linear Actuator in Another Embodiment] Figure 14 shows the configuration of a linear actuator 220 in another embodiment. In the linear actuator 50, magnets 53 are arranged on both sides in the opposite direction, flanking the movable coil 54.

[0106] As shown in Figure 14, the linear actuator 220 does not have a magnet 53 on the first yoke 51 side, unlike the linear actuator 50. That is, in the linear actuator 220, the magnet 53 and the first yoke 51 are positioned opposite each other with the movable coil 54 in between.

[0107] Even with such a linear actuator 220, it is possible to miniaturize it and improve thrust efficiency, just like with the linear actuator 50.

[0108] [2.4. Second Linear Actuator in Another Embodiment] Figure 15 shows the configuration of a linear actuator 230 in another embodiment. As shown in Figure 15, in the linear actuator 230, projections 231 are provided between the magnets 53 aligned in the optical axis direction, each projecting toward the movable coil 54 from the first yoke 51 and the second yoke 52.

[0109] The presence of the projection 231 makes it easier to position the magnet 53 and reduces the likelihood of the magnet 53 shifting out of place.

[0110] [2.5. Third Linear Actuator in Another Embodiment] Figure 16 shows the configuration of a linear actuator 240 in another embodiment. As shown in Figure 16, the linear actuator 240 includes a first yoke 241 and a second yoke 242 in place of the first yoke 51 and second yoke 52 in the linear actuator 50.

[0111] As described above, the magnet 53 attached to the first yoke 51 and the magnet 53 attached to the second yoke 52 generate an attractive force. Therefore, the first yoke 51 and the second yoke 52 may bend so that their central portions in the optical axis direction move closer together.

[0112] Therefore, the first yoke 241 and the second yoke 242 are formed with a curve so that, when the magnet 53 is not attached, the central portion in the width direction is separated from the movable coil 54 from the end.

[0113] As a result, the linear actuator 240, with the magnets 53 attached to the first yoke 241 and the second yoke 242 as shown by the dashed lines in the figure, can be aligned in a straight line in the optical axis direction by the attractive force of the magnets 53.

[0114] [2.6. Fourth Linear Actuator in Another Embodiment] Figure 17 shows the configuration of a linear actuator 250 in another embodiment. As shown in Figure 17, the linear actuator 250 is equipped with a first yoke 251 and a second yoke 52 in place of the first yoke 51 and second yoke 52 in the linear actuator 50.

[0115] The first yoke 251 has ribs 251a formed at both ends in the width direction, aligned with the optical axis direction. The second yoke 252 has ribs 252a formed in the central part in the width direction, aligned with the optical axis direction.

[0116] The first yoke 251 and the second yoke 252 have increased strength due to the formation of ribs 251a and ribs 252a, respectively, and deformation due to the attractive force between the opposing magnets 53 can be reduced.

[0117] Furthermore, by arranging the first yoke 251 on both sides in the width direction, when the lens holder 39 is formed in a cylindrical shape, the ribs 251a can be placed between the lens holder 39, which is formed to conform to the shape of the lens holder 39, and the first yoke 251. This makes it possible to miniaturize the lens device 3 as a whole.

[0118] Furthermore, by positioning the second yoke 252 in the central part in the width direction, the rib 251a can be placed between the inner cylinder 32 and the second yoke 252. This makes the lens device 3 smaller overall.

[0119] Furthermore, the configuration may be such that either the first yoke 251 or the second yoke 252 is replaced with either the first yoke 51 or the second yoke 52.

[0120] [2.7. Fifth Linear Actuator in Other Embodiments] Figures 18 and 19 show the configuration of a linear actuator 260 in another embodiment. As shown in Figures 18 and 19, the linear actuator 260 includes a magnet 261 and a metal tube 262 in place of the first yoke 51, second yoke 52 and magnet 53 in the linear actuator 50.

[0121] The magnets 261 are arranged in a Halbach array along the optical axis. The metal tube 262 is made of a magnetic metal material and covers the magnets 261.

[0122] The magnet 261 and the metal tube 262 are formed with a substantially elliptical cross-section as a whole, which allows for a higher thrust efficiency relative to weight compared to the case where the cross-section is circular.

[0123] In addition, the linear actuator 260 may have a first yoke 51 and a second yoke 52 provided on the outside of the magnet 261 and the metal tube 262.

[0124] [2.8. Sixth Linear Actuator in Another Embodiment] Figure 20 shows the configuration of a linear actuator 270 in another embodiment. In the linear actuator 50, magnets 53 are arranged on both sides in the opposite direction with a movable coil 54 in between, and a first yoke 51 and a second yoke 52 are arranged on both sides in the opposite direction with a pair of magnets 53 and a movable coil 54 in between.

[0125] As shown in Figure 20, the linear actuator 270 lacks the first yoke 51 and the magnet 53 on the first yoke 51 side, compared to the linear actuator 50. In other words, the linear actuator 270 only has the magnet 53 and the second yoke 52 located radially outward from the movable coil 54. To put it another way, the magnet 53 is positioned only in one direction opposite to the movable coil 54, and the yoke consists only of the second yoke 52, which is positioned in the same direction as the magnet 53 in the direction opposite to the movable coil 54.

[0126] Even with such a linear actuator 270, miniaturization is possible, similar to the linear actuator 50, and thrust efficiency can be improved. Furthermore, because the linear actuator 270 does not have a magnet 53 and a first yoke 51 on the opposite side of the movable coil 54, no attractive force is generated on either side of the movable coil 54, making assembly easier and reducing the deflection of the yoke due to the attractive force.

[0127] <3. Summary> As described above, the lens device 3 of the embodiment includes a lens 23b, a lens holder 39 that holds the lens 23b and is movable in the optical axis direction of the lens 23b, and a linear actuator 50 (220, 230, 240, 250, 260) that moves the lens holder 39. The linear actuator 50 includes a plurality of magnets 53 arranged along the optical axis direction, and two-phase movable coils 54a, 54b (201a, 201b, 211a, 211b) attached to the lens holder 39, facing the magnets 53 in opposing directions perpendicular to the optical axis direction, and aligned in the optical axis direction with a phase shift of 90 degrees ± 45 degrees in electrical angle. At least one of the two-phase movable coils 54 includes a pair of flat portions 61 extending in a width direction perpendicular to the optical axis direction and the opposing direction, and a pair of bent portions 62 that connect the ends of the pair of flat portions 61 and bend in the opposing direction. The bent portion 62 is positioned so as not to overlap with the magnet 53 in the opposing direction.

[0128] As a result, in the lens device 3, the flat portions 61 of the movable coils 54a and 54b are arranged without gaps in the optical axis direction, which allows for weight reduction and miniaturization, as well as suppression of thrust reduction. Therefore, the lens device 3 can improve thrust efficiency in terms of both weight ratio and volume ratio.

[0129] The two-phase movable coils 54a and 54b are formed to have the same shape. This reduces manufacturing costs compared to when the pair of movable coils 54a and 54b are formed to have different shapes.

[0130] At least one of the two-phase movable coils 211a and 211b, the movable coil 211b, is formed to be flat overall. This eliminates the need to bend the movable coil 211b during its creation, making its manufacture easier.

[0131] The movable coil 54 is attached to the lens holder 39 at the bent portion 62. This eliminates the need to widen the gap between the magnet 53 and the movable coil 54 using the member for attaching the movable coil 54 to the lens holder 39, thereby improving propulsion efficiency.

[0132] The movable coil 54 is formed by winding a wire. The end 63 of the wire is pulled out from the bent portion 62. This does not affect the distance between the magnet 53 and the movable coil 54 when pulling out the wire, thus improving propulsion efficiency.

[0133] The magnets 53 are positioned on both sides of the movable coil 54, in opposite directions. This allows magnetic fields to be generated from both sides in the direction opposite to the movable coil 54, thereby increasing the thrust.

[0134] The magnet 53 is positioned on only one side in the opposing direction with respect to the movable coil 54. The lens device 3 includes a yoke positioned on the other side in the opposing direction with respect to the movable coil 54. Here, the yoke is the first yoke 51. This allows the linear actuator 50 to be made thinner in the opposing direction, thus enabling miniaturization.

[0135] The magnet 53 is positioned on only one side in the direction opposite to the movable coil 54. The lens device 3 is equipped with a yoke positioned only in the same direction as the magnet 53 in the direction opposite to the movable coil 54. Here, the yoke is the second yoke 52. This allows the linear actuator 50 to be made thinner in the opposite direction and thus miniaturized. Furthermore, since the magnet 53 and the first yoke 51 are not provided on the opposite side of the movable coil 54, no attractive force is generated on either side of the movable coil 54, making assembly easier and reducing the deflection of the yoke due to the attractive force.

[0136] The length of the magnet 53 in the width direction is more than twice the length of the linear actuator 50 in the opposing direction. By making the aspect ratio of the linear actuator 50 1:2 or more in this way, it is possible to reduce the weight while generating the same thrust.

[0137] The magnets 53 are arranged in a line with gaps in the direction of the optical axis. The proportion of magnets 53 present in the direction of the optical axis is in the range of 0.6 to 0.8. This makes it possible to reduce weight while suppressing the reduction in thrust.

[0138] The linear actuator 230 includes a projection 231 positioned between adjacent magnets 53 that are aligned in the optical axis direction. This facilitates the positioning of the magnets 53 and reduces the likelihood of the magnets 53 shifting out of place.

[0139] The system includes a yoke to which the magnet 53 is attracted. Here, the yokes are a first yoke 241 and a second yoke 242. The yokes are formed with a curve so that the central portion in the optical axis direction is separated from the end from the movable coil. As a result, the first yoke 241 and the second yoke 242 can be straightened in the optical axis direction by the attractive force of the magnet 53 when the magnet 53 is attached.

[0140] The device includes a yoke to which the magnet 53 is attracted. Here, the yokes are a first yoke 241 and a second yoke 242. The yokes have ribs 251a and 252b formed along the optical axis. This increases the strength of the first yoke 251 and the second yoke 252 and reduces deformation caused by the attractive force between the opposing magnets 53.

[0141] The yokes are positioned on both sides of the movable coil 54, in opposing directions. The yoke on the lens holder 39 side (first yoke 251) has ribs 251a formed at both ends in the width direction. This allows the ribs 251a to be positioned between the lens holder 39, which is formed to conform to the shape of the lens holder 39, and the first yoke 251, when the lens holder 39 is formed in a cylindrical shape. This makes it possible to miniaturize the lens device 3 as a whole.

[0142] The yokes are positioned on both sides of the movable coil 54 in opposing directions. The yoke (second yoke 252) that is further away from the lens holder 39 than the movable coil 54 has a rib 252a formed in the central part in the opposing direction. This allows a rib 251a to be placed between the inner cylinder 32 and the second yoke 242. This makes it possible to miniaturize the lens device 3 as a whole.

[0143] The magnets 261 are arranged in a Halbach array in the direction of the optical axis. This allows for high thrust efficiency.

[0144] The magnet 261 is formed so that its length in the width direction is longer than its length in the opposing direction. This helps to suppress a decrease in thrust efficiency.

[0145] As described above, the imaging device 1 of the embodiment includes an image sensor 13 that converts an optical image into an electrical signal, a lens 23b that guides light to the image sensor 13, a lens holder 39 that holds the lens 23b and is movable in the optical axis direction of the lens 23b, and a linear actuator 50 that moves the lens holder 39. The linear actuator 50 includes a plurality of magnets 53 arranged along the optical axis direction, and two-phase movable coils 54 attached to the lens holder 39, facing the magnets 53 in opposing directions perpendicular to the optical axis direction, and aligned in the optical axis direction with a phase shift of 90 degrees ± 45 degrees in electrical angle. At least one of the two-phase movable coils 54 includes a pair of flat portions 61 extending in a width direction perpendicular to the optical axis direction and the opposing direction, and a pair of bent portions 62 that connect the ends of the pair of flat portions 61 and bend in the opposing direction. The bent portions 62 are positioned so as not to overlap with the magnets 53 in the opposing direction. Even with such an imaging device 1, the same effects as the lens device 3 can be obtained.

[0146] Furthermore, the effects described herein are merely illustrative and not limited to those described herein, and other effects may also occur.

[0147] <4. This Technology> This technology can also be configured as follows: (1) A lens device comprising: a lens; a lens holder that holds the lens and is movable in the optical axis direction of the lens; and a linear actuator that moves the lens holder, wherein the linear actuator comprises: a plurality of magnets arranged along the optical axis direction; and two-phase movable coils attached to the lens holder, facing the magnets in opposing directions perpendicular to the optical axis direction, and aligned in the optical axis direction with a phase difference of 90 degrees ± 45 degrees in electrical angle, wherein at least one of the two-phase movable coils comprises: a pair of flat portions extending in a width direction perpendicular to the optical axis direction and the opposing direction; and a pair of bent portions connecting the ends of the pair of flat portions and bending in the opposing direction, wherein the bent portions are positioned so as not to overlap with the magnets in the opposing direction. (2) The lens device according to (1), wherein the two-phase movable coils are formed in the same shape. (3) The lens device according to (1), wherein at least the other of the two-phase movable coils is formed to be flat overall. (4) The lens device according to any one of (1) to (3), wherein the movable coil is attached to the lens holder at the bent portion. (5) The lens device according to any one of (1) to (4), wherein the movable coil is formed by winding a wire, and the end of the wire is pulled out from the bent portion. (6) The lens device according to any one of (1) to (5), wherein the magnets are arranged on both sides of the movable coil in the opposing direction. (7) The lens device according to any one of (1) to (5), wherein the magnets are arranged on only one side of the opposing direction with respect to the movable coil, and a yoke is arranged on the other side of the opposing direction with respect to the movable coil. (8) The lens device according to any one of (1) to (5), wherein the magnets are arranged on only one side of the opposing direction with respect to the movable coil, and a yoke is arranged only in the same direction as the magnets in the opposing direction with respect to the movable coil.(9) The lens device according to any one of (1) to (8), wherein the length of the magnet in the width direction is at least twice the length of the linear actuator in the opposing direction. (10) The lens device according to any one of (1) to (9), wherein the magnets are arranged in a row with gaps in the optical axis direction, and the proportion of magnets 53 present in the optical axis direction is in the range of 0.6 to 0.8. (11) The lens device according to (10), wherein the linear actuator is provided with a projection positioned between adjacent magnets arranged in the optical axis direction. (12) The lens device according to (6), comprising a yoke to which the magnets are attracted, wherein the yoke is formed to be curved such that the central portion in the optical axis direction is separated from the end from the movable coil. (13) The lens device according to any one of (1) to (12), comprising a yoke to which the magnets are attracted, wherein the yoke has ribs formed along the optical axis direction. (14) The lens device according to (13), wherein the yokes are arranged on both sides in the opposing direction with the movable coil in between, and the yoke on the lens holder side has the ribs formed at both ends in the width direction. (15) The lens device according to (13) or (14), wherein the yokes are arranged on both sides in the opposing direction with the movable coil in between, and the yoke spaced further away from the lens holder than the movable coil has the ribs formed in the central portion in the width direction. (16) The lens device according to any one of (1) to (15), wherein the magnets are arranged in a Halbach arrangement in the optical axis direction. (17) The lens device according to (16), wherein the length in the width direction of the magnets is longer than the length in the opposing direction.(18) Imaging device comprising: an image sensor that converts an optical image into an electrical signal; a lens that guides light to the image sensor; a lens holder that holds the lens and is movable in the optical axis direction of the lens; and a linear actuator that moves the lens holder, wherein the linear actuator comprises: a plurality of magnets arranged along the optical axis direction; and two-phase movable coils attached to the lens holder, facing the magnets in opposing directions perpendicular to the optical axis direction, and aligned in the optical axis direction with a phase difference of 90 degrees ± 45 degrees in electrical angle, wherein at least one of the two-phase movable coils comprises: a pair of flat portions extending in a width direction perpendicular to the optical axis direction and the opposing direction; and a pair of bent portions connecting the ends of the pair of flat portions and bending in the opposing direction, wherein the bent portions are positioned so as not to overlap with the magnets in the opposing direction.

[0148] 1 Imaging device 3 Lens device 23 Lens 23 39 Lens holder 50 Linear actuator 53 Magnet 54 Movable coil 61 Flat section 62 Bent section

Claims

1. A lens device comprising: a lens; a lens holder that holds the lens and is movable in the optical axis direction of the lens; and a linear actuator that moves the lens holder, wherein the linear actuator comprises: a plurality of magnets arranged along the optical axis direction; and two-phase movable coils attached to the lens holder, facing the magnets in opposing directions perpendicular to the optical axis direction, and aligned in the optical axis direction with a phase difference of 90 degrees ± 45 degrees in electrical angle, wherein at least one of the two-phase movable coils comprises: a pair of flat portions extending in a width direction perpendicular to the optical axis direction and the opposing direction; and a pair of bent portions connecting the ends of the pair of flat portions and bending in the opposing direction, wherein the bent portions are positioned so as not to overlap with the magnets in the opposing direction.

2. The lens device according to claim 1, wherein the two-phase movable coils are formed to the same shape.

3. The lens device according to claim 1, wherein at least the other of the two-phase movable coils is formed to be flat overall.

4. The lens device according to claim 1, wherein the movable coil is attached to the lens holder at the bent portion.

5. The lens device according to claim 1, wherein the movable coil is formed by winding a wire, and the end of the winding is drawn out from the bent portion.

6. The lens device according to claim 1, wherein the magnets are arranged on both sides in the opposing direction, sandwiching the movable coil.

7. The lens device according to claim 1, wherein the magnet is positioned only in one of the opposing directions relative to the movable coil, and the yoke is positioned on the other side of the movable coil in the opposing direction.

8. The lens device according to claim 1, wherein the magnet is positioned in only one of the opposing directions relative to the movable coil, and the yoke is positioned only in the same direction as the magnet in the opposing direction relative to the movable coil.

9. The lens device according to claim 1, wherein the length of the magnet in the width direction is twice or more the length of the linear actuator in the opposing direction.

10. The lens device according to claim 1, wherein the magnets are arranged in a line with gaps in the direction of the optical axis, and the proportion of the magnets 53 present in the direction of the optical axis is in the range of 0.6 to 0.

8.

11. The lens device according to claim 10, wherein the linear actuator comprises a projection positioned between adjacent magnets arranged in the direction of the optical axis.

12. The lens device according to claim 6, comprising a yoke to which the magnet is attracted, wherein the yoke is formed to be curved such that its central portion in the optical axis direction is separated from the end portion from the movable coil.

13. The lens device according to claim 1, comprising a yoke to which the magnet is attracted, wherein the yoke has ribs formed along the optical axis direction.

14. The lens device according to claim 13, wherein the yokes are arranged on both sides in the opposing direction with respect to the movable coil, and the yoke on the lens holder side has the ribs formed at both ends in the width direction.

15. The lens device according to claim 13, wherein the yoke is arranged on both sides in the opposing direction with respect to the movable coil, and the rib is formed in the central portion in the width direction of the yoke that is spaced further away from the lens holder than the movable coil.

16. The lens device according to claim 1, wherein the magnets are arranged in a Halbach arrangement in the direction of the optical axis.

17. The lens device according to claim 16, wherein the length of the magnet in the width direction is longer than the length in the opposing direction.

18. An imaging device comprising: an image sensor that converts an optical image into an electrical signal; a lens that guides light to the image sensor; a lens holder that holds the lens and is movable in the optical axis direction of the lens; and a linear actuator that moves the lens holder, wherein the linear actuator comprises: a plurality of magnets arranged along the optical axis direction; and two-phase movable coils attached to the lens holder, facing the magnets in opposing directions perpendicular to the optical axis direction, and aligned in the optical axis direction with a phase difference of 90 degrees ± 45 degrees in electrical angle, wherein at least one of the two-phase movable coils comprises: a pair of flat portions extending in a width direction perpendicular to the optical axis direction and the opposing direction; and a pair of bent portions connecting the ends of the pair of flat portions and bending in the opposing direction, wherein the bent portions are positioned so as not to overlap with the magnets in the opposing direction.

Images