Lens barrel and imaging device

Abstract

The lens barrel includes: a first frame that holds a lens; a drive unit that includes a drive shaft and drives the first frame in the optical axis direction; and a second frame having at least two guide portions for guiding the driving of the first frame in the optical axis direction, at least one of the at least two guide portions being disposed on a second straight line passing through the optical axis and orthogonal to a first straight line passing through the axis of the drive axis and the optical axis in a plane orthogonal to the optical axis.

Description

Technical Field

[0001] The present invention relates to a lens barrel and an imaging device. Background Art

[0002] In an optical device such as a lens barrel, a lens moving device that moves a lens group during a zoom operation or a focusing operation is mounted.

[0003] It is desired to improve the position control accuracy of the lens group.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: WO 2018 / 105200 Summary of the Invention

[0007] According to a first aspect, a lens barrel includes: a first frame that holds a lens; a driving unit that includes a driving shaft and drives the first frame in the optical axis direction; and a second frame that has at least two guiding portions that guide the driving of the first frame in the optical axis direction, and in a plane orthogonal to the optical axis, at least one of the at least two guiding portions is disposed on a second straight line that is orthogonal to a first straight line passing through the axis of the driving shaft and the optical axis and passes through the optical axis.

[0008] According to a second aspect, a lens barrel includes: a first frame that holds a lens; a driving unit that includes a driving shaft and drives the first frame in the optical axis direction; a second frame that has at least two guiding portions that guide the driving of the first frame in the optical axis direction; an inner ring that is fixed to the first frame; and an outer ring that is capable of relative rotation with respect to the inner ring, and an outer peripheral surface of the outer ring abuts against the guiding portion.

[0009] According to a third aspect, a lens barrel includes a first frame and a second frame that relatively move in the optical axis direction, and the lens barrel includes at least two drip-proof members that are provided in a gap that communicates the outside and the inside of the lens barrel between the first frame and the second frame.

[0010] According to a fourth aspect, an imaging device includes the above lens barrel.

[0011] In addition, the structure of the embodiments described below can be appropriately modified, and also, at least a part thereof can be replaced with other structures. Furthermore, constituent elements that are not particularly limited in terms of their configuration are not limited to the configurations disclosed in the embodiments, and can be disposed at positions where their functions can be achieved. Brief Description of the Drawings

[0012] Figure 1 of (A) and Figure 1(B) is a cross-sectional view showing the structure of a camera equipped with a lens barrel according to an embodiment. Figure 1 (A) shows the state at infinity. Figure 1 (B) shows the state at the nearest point.

[0013] Figure 2 is a perspective view of the first fixed barrel member.

[0014] Figure 3 is an exploded perspective view of the optical system block portion.

[0015] Figure 4 (A) is an exploded perspective view of the moving block portion. Figure 4 (B) is a perspective view of the moving block portion observed from the image plane side.

[0016] Figure 5 is to Figure 1 A diagram obtained by magnifying the portion C1 surrounded by the dashed line in (A).

[0017] Figure 6 is a perspective view for explaining the structure of the drive mechanism.

[0018] Figure 7 is a cross-sectional view for explaining the structure of the drive mechanism.

[0019] Figure 8 is a diagram for explaining the arrangement of the first to third guide grooves.

[0020] Figure 9 (A) is a diagram schematically showing an arrangement example of the first to third guide grooves of a comparative example. Figure 9 (B) is a diagram for explaining the reason for arranging the first guide groove and the second guide groove on the second straight line.

[0021] Figure 10 (A) is to Figure 1 A diagram obtained by magnifying the portion C2 surrounded by the dashed line in (A). Figure 10 (B) is a cross-sectional view showing the drip-proof structure of the comparative example. Detailed Embodiments

[0022] Hereinafter, the lens barrel according to the embodiment will be described in detail with reference to the drawings. In addition, the scales of the shapes, lengths, thicknesses, etc. of the respective parts shown in the embodiment are not necessarily the same as those of the actual object. Also, in each drawing, for ease of understanding, sometimes the illustration of a part of the elements is omitted. In addition, sometimes the hatching of a part of the elements is omitted in the cross-sectional view.

[0023] Figure 1 (A) and Figure 1 (B) are cross-sectional views showing the structure of a camera 1 equipped with a lens barrel 2 according to an embodiment.Figure 1 (A) shows the state of infinity, Figure 1 (B) shows the closest state.

[0024] like Figure 1 (A) and Figure 1 As shown in (B) of FIG, the camera 1 includes a camera body 3 and a lens barrel 2. The lens barrel 2 has a lens mount LM at its rear portion (base end portion). The lens mount LM engages with a body mount (not shown) of the camera body 3, thereby allowing the lens barrel 2 to be detachably mounted to the camera body 3. In this embodiment, the lens barrel 2 is detachably mounted to the camera body 3, but the present invention is not limited thereto. The lens barrel 2 and the camera body 3 may also be integrally formed.

[0025] The camera body 3 internally includes an image sensor IS and a control unit (not shown). The image sensor IS is composed of a photoelectric conversion element such as a CCD (Charge Coupled Device), and converts the subject image formed by the imaging optical system (the lens barrel 2 attached to the camera body 3) into an electrical signal.

[0026] The control unit includes a CPU (Central Processing Unit) and the like, and comprehensively controls the entire operation of the camera 1 related to photography, including focus driving, in the camera body 3 and the attached lens barrel 2 .

[0027] The lens barrel 2 includes a fixed barrel 13, a focus ring 12, and an optical block 100. The lens barrel 2 moves in the direction of the optical axis OA in response to operation of the focus ring 12 or user operation via the camera body 3. A first fixed barrel member 13a and a second fixed barrel member 13b are disposed within the fixed barrel 13. The optical block 100 is an example of a first frame, and the first fixed barrel member 13a is an example of a second frame.

[0028] Figure 2 : is a perspective view of the first fixed cylinder member 13a. Figure 2 As shown, a first guide groove 11a, a second guide groove 11b, and a third guide groove 11c are formed on the inner periphery of the first fixed cylinder member 13a for guiding the optical system block 100 along the optical axis OA. The first guide groove 11a to the third guide groove 11c are linear grooves extending along the optical axis OA, and their bottom surfaces are stepped so that the bottom surface on the object side is located on the outer diameter side relative to the bottom surface on the image plane side (see FIG. Figure 1 (A) and Figure 1 (B)). The details of the arrangement of the first to third guide grooves 11a to 11c will be described later. The first to third guide grooves 11a to 11c are examples of guide portions.

[0029] Figure 3 is an exploded perspective view of the optical system block portion 100. As shown in Figure 1 (A) of Figure 1 (B) of Figure 3 and as shown in

[0030] the optical system block portion 100 includes a lens holding frame F1, a lens group L1, a diaphragm mechanism 40, a moving block portion 200, a lens holding frame F2, and a lens group L2.

[0031] The lens groups L1 and L2 are arranged in sequence along the common optical axis OA. The lens group L1 is held by the lens holding frame F1, and the lens group L2 is held by the lens holding frame F2. The lens groups L1 and L2 are focusing lens groups. As described above, the optical system block portion 100 including the lens groups L1 and L2 moves in the direction of the optical axis OA according to the operation of the focusing operation ring 12 and the operation by the user via the camera body 3, etc. That is, the lens barrel 2 of the present embodiment employs a focusing method of the overall extension type that drives the entire optical system as a focusing group. Thereby, compared with the case of adopting an internal focusing method, for example, the overall length of the lens barrel 2 in the direction of the optical axis OA can be shortened. That is, the lens barrel 2 can be miniaturized.

[0032] The diaphragm mechanism 40 is disposed between the lens groups L1 and L2.

[0033] Figure 4 (A) of Figure 4 is an exploded perspective view of the moving block portion 200, Figure 5 and Figure 1 (B) of Figure 4 is a perspective view of the moving block portion 200 observed from the image plane side. In addition, Figure 4 (A) of

[0034] is a view obtained by magnifying the portion C1 surrounded by the dashed line in Figure 5 (A) of

[0035] As shown in Figure 5 in the present embodiment, the first biasing member 81 is a coil spring. As shown in Figure 5As shown, the first biasing member 81 is received in a hole 20b provided in the moving part 20. One end thereof contacts the bottom 20c of the hole 20b, and the other end contacts the biasing part holding part 30. Thus, as shown by the arrow A2 in Figure 5 , the moving part 20 is biased toward the connecting part 10, thereby suppressing loosening in the optical axis direction between the moving part 20 and the connecting part 10. When the moving part 20 moves in the optical axis direction, the connecting part 10 also moves in the optical axis direction. In addition, the first biasing member 81 only needs to be able to bias the moving part 20 toward the connecting part 10, and is not limited to a coil spring, and may also be a leaf spring or the like.

[0036] As Figure 4 shown in (B) of Figure 5 and as shown, the second biasing member 82 is a coil spring. One end thereof contacts the moving part 20, and the other end contacts the biasing part holding part 30. Thus, as shown by the arrow A1 in Figure 5 , the moving part 20 is biased toward a lead screw 302 described later. In addition, the second biasing member 82 only needs to be able to bias the moving part 20 toward the lead screw 302, and is not limited to a coil spring, and may also be a leaf spring or the like.

[0037] As Figure 3 shown, a lens holding frame F1 and a lens holding frame F2 are connected to the connecting part 10. Specifically, the lens holding frame F1 is fixed to the connecting part 10 by a screw 71, and the lens holding frame F2 is fixed to the connecting part 10 by a screw 72.

[0038] As described above, the connecting part 10 is connected to the moving part 20 through the first biasing member 81 and the biasing part holding part 30. Thus, when the moving part 20 moves in the optical axis OA direction, the lens holding frames F1 and F2 move in the optical axis OA direction.

[0039] In addition, as Figure 4 shown in (A) of Figure 4 and (B) of

[0040] and the like, the connecting part 10 includes a cylindrical part 10a, a first groove engaging part 101a, a second groove engaging part 101b, and a third groove engaging part 101c that project radially from the cylindrical part 10a.

[0041] The front bearing 102a and the rear bearing 103a are engaged with the first guide groove 11a. The front bearing 102a and the rear bearing 103a rotate and move along the first guide groove 11a. Thus, the friction generated when the first groove engaging portion 101a moves within the first guide groove 11a becomes rolling friction. Therefore, for example, compared with the case where the front protrusion 112a and the rear protrusion 113a are engaged with the first guide groove 11a without passing through a bearing, when the first groove engaging portion 101a moves within the first guide groove 11a, the sliding resistance is reduced, and the load applied to the drive unit (the stepping motor 301 described later) for moving the moving portion 20 in the optical axis OA direction can be reduced.

[0042] Similar to the first groove engaging portion 101a, the second groove engaging portion 101b has a front protrusion 112b (not shown) and a rear protrusion 113b (not shown) that protrude radially and are arranged separately in the optical axis OA direction, a front bearing 102b, and a rear bearing 103b. The outer periphery of the front protrusion 112b is fitted with the inner ring of the front bearing 102b, and the outer periphery of the rear protrusion 113b is fitted with the inner ring of the rear bearing 103b. Thus, the front bearing 102b and the rear bearing 103b are arranged separately in the optical axis OA direction.

[0043] The front bearing 102b and the rear bearing 103b are engaged with the second guide groove 11b. Thus, the friction generated when the second groove engaging portion 101b moves within the second guide groove 11b becomes rolling friction. Therefore, for example, compared with the case where the front protrusion 112b and the rear protrusion 113b are engaged with the second guide groove 11b without passing through a bearing, the load applied to the stepping motor 301 when the second groove engaging portion 101b moves within the second guide groove 11b can be reduced.

[0044] Similar to the first groove engaging portion 101a, the third groove engaging portion 101c has a front protrusion 112c and a rear protrusion 113c (refer to (A) of Figure 1 and Figure 1 (B)) that protrude radially and are arranged separately in the optical axis OA direction, a front bearing 102c, and a rear bearing 103c. The outer periphery of the front protrusion 112c is fitted with the inner ring of the front bearing 102c, and the outer periphery of the rear protrusion 113c is fitted with the inner ring of the rear bearing 103c. Thus, the front bearing 102c and the rear bearing 103c are arranged separately in the optical axis OA direction.

[0045] The front bearing 102c and the rear bearing 103c are engaged with the third guide groove 11c. Thus, the friction generated when the third groove engaging portion 101c moves in the third guide groove 11c becomes rolling friction. Therefore, for example, compared with the case where the front protrusion 112c and the rear protrusion 113c are engaged with the third guide groove 11c without passing through the bearing, the load applied to the stepping motor 301 when the third groove engaging portion 101c moves in the third guide groove 11c can be reduced.

[0046] In addition, in the present embodiment, the rear bearing 103a is located on the inner diameter side of the front bearing 102a, the rear bearing 103b is located on the inner diameter side of the front bearing 102b, and the rear bearing 103c is located on the inner diameter side of the front bearing 102c. Thus, as shown in (B) of Figure 1 , a space for disposing other components such as a flexible substrate can be ensured on the outer peripheral side of the rear bearings 103a to 103c. In addition, according to this structure, the distance between the front bearing 102a and the rear bearing 103a, the distance between the front bearing 102b and the rear bearing 103b, and the distance between the front bearing 102c and the rear bearing 103c can be extended. Thus, the inclination of the central axes of the lens groups L1 and L2 with respect to the optical axis OA can be suppressed, and therefore the optical performance of the lens barrel 2 can be improved. In addition, the distance between the front bearing 102a and the rear bearing 103a, the distance between the front bearing 102b and the rear bearing 103b, and the distance between the front bearing 102c and the rear bearing 103c can be the same or different from each other.

[0047] As described above, the focusing method of the lens barrel 2 of the present embodiment is the overall extension method, so the optical system block portion 100 protrudes from the lens barrel 2. In this case, when the lens barrel 2 falls, an impact is directly applied to the focusing lens group. By supporting the optical system block portion 100 by using the first guide groove 11a to the third guide groove 11c and the first groove engaging portion 101a to the third groove engaging portion 101c of the present embodiment, the strength against impact can be improved compared with the case of supporting the optical system block portion 100 by using, for example, a single guide rod.

[0048] As shown in Figure 4 (A), in the moving portion 20, there are formed: a hole 20a for accommodating the lead screw engaging portion 303 of the drive mechanism 300 that drives the optical system block portion 100; and a hole 20b for accommodating the first biasing member 81 described above. Here, the drive mechanism 300 for driving the optical system block portion 100 will be described.

[0049] Figure 6 It is a perspective view for explaining the structure of the drive mechanism 300 and a perspective view of the drive mechanism 300 and the optical system block portion 100 observed from the image plane side. Figure 7This is a cross-sectional view for explaining the structure of the drive mechanism 300. Figure 8 This is a view for explaining the arrangement of the first to third guide grooves, and is a top view of the optical system block portion 100 and the first fixed cylinder member 13a as viewed from the object side.

[0050] As Figure 6 shown, the drive mechanism 300 includes a stepping motor 301, a lead screw 302, and a lead screw engagement portion 303.

[0051] In the present embodiment, a stepping motor 301 is used as a drive source for the lead screw 302. When the user operates the focus operation ring 12 or operates via the camera body 3 or the like, a lens internal control unit (not shown) rotates the lead screw 302 according to the operation amount, whereby the optical system block portion 100 moves in the optical axis OA direction.

[0052] In the present embodiment, the position of the optical system block portion 100 is controlled by open-loop control of the stepping motor 301. That is, the position of the optical system block portion 100 is not detected and fed back to the lens internal control unit. Thereby, a position detection unit (feedback sensor or the like) for feedback control of the position of the optical system block portion 100 can be omitted, and thus miniaturization and cost reduction of the lens barrel 2 can be achieved. The position of the optical system block portion 100 is represented by the number of steps (rotation speed) of the stepping motor 301, and thus the position data represented by the number of steps is sent to the camera body 3 and the lens internal control unit as needed.

[0053] As Figure 8 shown, in the present embodiment, the output shaft 301a of the stepping motor 301 is connected to the lead screw 302 via gears 305a to 305c. Specifically, as Figure 8As shown, an output shaft 301a is disposed on the object side of the stepping motor 301. A gear 305a is mounted on the object-side end of the output shaft 301a of the stepping motor 301, a gear 305b is mounted on the object-side end of the lead screw 302, and a gear 305c engaged with the gears 305a and 305b is disposed between the gears 305a and 305b. The combined optical axis direction length of the stepping motor 301 and the output shaft 301a is substantially equal to the optical axis direction length of the lead screw 302. Therefore, on the image side of the gears 305a to 305c, the stepping motor 301 and its output shaft 301a are disposed in parallel with the lead screw 302. Thus, a rotational force is transmitted from the object-side end of the output shaft 301a of the stepping motor 301 to the object-side end of the lead screw 302 via the gear 305c. According to this structure, the output shaft 301a of the stepping motor 301 and the lead screw 302 are folded and disposed, so that the overall length in the optical axis OA direction of the lens barrel 2 can be shortened compared with the case where the output shaft and the lead screw are directly connected. The combined optical axis direction length of the stepping motor 301 and the output shaft 301a and the optical axis direction length of the lead screw 302 can be appropriately changed.

[0054] As Figure 7 shown, the lead screw 302 is supported by a lead screw support mechanism 304 and a first fixed cylinder member 13a so as to be rotatable. In the present embodiment, the lead screw support mechanism 304 supports one end of the lead screw 302 via a bearing 304a so as to be rotatable, and the first fixed cylinder member 13a supports the other end of the lead screw 302 via a bearing 304b so as to be rotatable. By supporting both ends of the lead screw 302 with bearings in this way, the load applied to the stepping motor 301 when the lead screw 302 rotates can be reduced. In this embodiment, the position of the optical system block portion 100 is controlled by open-loop control of the stepping motor 301. Therefore, when an excessive load is applied to the stepping motor 301, it is sometimes impossible to obtain the desired movement amount of the optical system block portion 100 for a specified driving amount of the stepping motor 301. Therefore, in the present embodiment, by reducing the load applied to the stepping motor 301, the position control accuracy of the optical system block portion 100 is improved.

[0055] As Figure 7 shown, the lead screw engagement portion 303 includes an annular member 303a and a bearing 303b. The outer periphery of the annular member 303a is fitted with the inner ring of the bearing 303b. The outer periphery of the bearing 303b is fitted with the inner periphery of a hole 20a provided in the moving portion 20.

[0056] A groove 313 that contacts the thread groove of the lead screw 302 is formed on the inner periphery of the annular member 303a. The groove 313 is a circumferential groove formed over the entire circumference of the inner periphery of the annular member 303a.

[0057] As Figure 7As shown by arrow A1, the annular member 303a is urged toward the lead screw 302 by the second urging member 82 in a direction orthogonal to the axial direction AX1 of the lead screw 302. Thereby, the groove 313 of the annular member 303a is pressed against the thread groove of the lead screw 302, thus suppressing looseness between the annular member 303a and the lead screw 302. In addition, the lead screw engaging portion 303 is received in the hole 20a formed in the moving portion 20, so that the moving portion 20 is connected to the lead screw engaging portion 303.

[0058] Since the annular member 303a is supported so as to be rotatable, when the lead screw 302 rotates, the annular member 303a is pressed by the tooth side surface of the thread groove of the lead screw 302 and moves in the axial direction of the lead screw 302 while rotating. Thereby, the moving portion 20 engaged with the lead screw engaging portion 303 also moves in the axial direction of the lead screw 302. As the moving portion 20 moves, the optical system block portion 100 is guided by the first guide groove 11a to the third guide groove 11c provided in the first fixed cylinder member 13a and moves in the optical axis OA direction.

[0059] The annular member 303a rotates and moves in the axial direction AX1 of the lead screw 302, so that the friction generated between the annular member 303a and the lead screw 302 becomes rolling friction. Thereby, the load applied to the stepping motor 301 when moving the optical system block portion 100 in the axial direction of the lead screw 302 can be reduced, and thus the position control accuracy of the optical system block portion 100 can be improved. In addition, as the structure of the lead screw engaging portion 303, the structure disclosed in Japanese Patent Application No. 2021-156263 can also be applied.

[0060] Next, the arrangement of the first guide groove 11a to the third guide groove 11c provided in the first fixed cylinder member 13a will be described. In the present embodiment, as Figure 8 shown, the first guide groove 11a and the second guide groove 11b are arranged on a second straight line LN2 that is orthogonal to a first straight line LN1 passing through the axis AX1 of the lead screw 302 and the optical axis OA and passes through the optical axis OA in a plane orthogonal to the optical axis OA. In addition, the third guide groove 11c is arranged on the first straight line LN1.

[0061] The reason for arranging the first guide groove 11a to the third guide groove 11c as described above will be described. Figure 9(A) is a diagram schematically showing an example of the arrangement of the first guide groove 901a, the second guide groove 901b, and the third guide groove 901c of the comparative example. In the comparative example, the first guide groove 901a to the third guide groove 901c are arranged at intervals of 120 degrees. At this time, if the loose clearance between the first guide groove 901a to the third guide groove 901c and, for example, the front bearings 102a to 102c is set to a, then the loose clearance b in the direction parallel to the first straight line LN1 passing through the axis AX1 of the screw 302 and the optical axis OA becomes, for example, b=a / cosθ in the first guide groove 901a, which is larger than the loose clearance a at the time of design, and therefore the optical system block 100 Figure 9 The wobble in the spacing direction in (A) increases, which in turn affects the driving accuracy. Therefore, in this embodiment, the first guide groove 11a and the second guide groove 11b are arranged at the position of b=a and θ=0°, that is, on the second straight line LN2 that is orthogonal to the first straight line LN1. This prevents the optical system block 100 from tipping over and improves the position accuracy of the optical system block 100. In addition, the third guide groove 11c located on the first straight line LN1 intervenes Figure 9 The yaw direction of (A) is shaken, but the position relationship of the fulcrum does not affect the driving performance near the center of the optical axis. In addition, in the driving performance of the peripheral part away from the optical axis, the direction of the third guide groove 11c is in the Figure 9 In the vertical direction (A), the smallest looseness is sufficient, and the shaking in the yaw direction is also small, so it will not have a significant impact on the driving accuracy.

[0062] Figure 9 (B) is a diagram for explaining another reason for arranging the first guide groove 11a and the second guide groove 11b on the second straight line LN2. Figure 9 (A) Similarly, the first guide groove 901a to the third guide groove 901c are arranged at intervals of 120 degrees. Figure 9 As shown in the figure on the right side of (B), the lens barrel 2 as a whole is tilted around the position (rotation center RC1) where the first guide groove 901a or the second guide groove 901b is provided. In this case, the position of the rotation center RC1 is offset from the center position of the lens group by the amount shown by D. This offset D is the offset in the optical axis direction caused by the tilting of the lens, which becomes a precision error. By configuring the first guide groove 11a and the second guide groove 11b on the second straight line LN2, the precision error caused by the position of the rotation center of the lens barrel 2 can be reduced. In addition, the third guide groove 11c located on the first straight line LN1 intervenes Figure 9 The yaw direction of (A) is shaken, but the position relationship of the fulcrum does not affect the driving performance near the center of the optical axis. In addition, in the driving performance of the peripheral part away from the optical axis, the direction of the third guide groove 11c is in theFigure 9 In the vertical direction in (A), thus only a minimum loosening is required, and only a small amount of swaying in the yaw direction is required, so it will not have a great impact on the precision error.

[0063] Thus, in the present embodiment, by reducing the load applied to the stepping motor 301 and arranging the first guide groove 11a to the third guide groove 11c as described above, the position control precision of the optical system block portion 100 is improved.

[0064] <Drip-proof structure>

[0065] In the lens barrel 2 of the present embodiment, the optical system block portion 100 moves in the optical axis OA direction. As Figure 1 shown in (B), sometimes the lens holding frame F1 protrudes from the lens barrel 2. At this time, it is not preferable that water droplets adhering to the lens holding frame F1 due to rainfall or the like enter the inside of the lens barrel 2 through the gap between the second fixed cylinder member 13b and the lens holding frame F1. Therefore, the lens barrel 2 has a drip-proof structure for preventing water droplets adhering to the lens holding frame F1 from entering the inside of the lens barrel 2.

[0066] Figure 10 (A) is a view for explaining the drip-proof structure 90 of the present embodiment, and is a view in which the portion C2 surrounded by a dotted line in (A) is enlarged. Figure 1

[0067] Figure 10 As Figure 10 shown in (A), the lens barrel 2 of the present embodiment includes: a lens holding frame F1 that moves in the optical axis direction; and a second fixed cylinder member 13b that is disposed radially outside the lens holding frame F1. As the lens holding frame F1 moves in the optical axis direction, the positional relationship between the lens holding frame F1 and the second fixed cylinder member 13b in the optical axis direction changes relatively. A space S is formed between the lens holding frame F1 and the second fixed cylinder member 13b as a gap that communicates the outside and the inside of the lens barrel 2. The drip-proof structure 90 is provided in the space S. The drip-proof structure 90 includes a first drip-proof member 91 and a second drip-proof member 92 formed of a raw material different from that of the first drip-proof member 91. The lens holding frame F1 is an example of the first frame, and the second fixed cylinder member 13b is an example of the second frame. In the present embodiment, the lens holding frame F1 can move in the optical axis OA direction relative to the second fixed cylinder member 13b, and the lens holding frame F1 and the second fixed cylinder member 13b do not rotate relative to each other in the circumferential direction.

[0068] The first drip-proof member 91 and the second drip-proof member 92 are arranged and disposed in the optical axis direction, and the first drip-proof member 91 is disposed closer to the object side than the second drip-proof member 92.

[0069] In the present embodiment, the first drip-proof member 91 is an elastic member having water absorbency (a member having cushioning properties), and is disposed so as to surround the outer periphery of the lens holding frame F1. As the material of the first drip-proof member 91, for example, a non-woven fabric structure, synthetic leather, flannelette, or flocked fabric can be cited. In the present embodiment, the first drip-proof member 91 is a non-woven fabric structure coated with a water-repellent agent on the surface facing the lens holding frame F1. The thickness of the first drip-proof member 91 is substantially fixed in the optical axis direction, and the cross section of the first drip-proof member 91 is rectangular.

[0070] A gap is provided between the first drip-proof member 91 and the lens holding frame F1. That is, the first drip-proof member 91 and the lens holding frame F1 do not contact each other. Thereby, compared with the case where the first drip-proof member 91 and the lens holding frame F1 are in contact, the sliding resistance is small, and the driving load when the optical system block portion 100 moves in the optical axis OA direction can be reduced. Therefore, the attitude of the optical system block portion 100 is stable, so that the optical performance of the lens barrel 2 is improved, and the load applied to the stepping motor 301 can be suppressed. Thereby, the position control accuracy of the optical system block portion 100 can be improved.

[0071] The second drip-proof member 92 is an elastic member coated with a coating for improving slidability, and is formed in a ring shape. The second drip-proof member 92 is, for example, a rubber sheet coated with a coating for improving slidability. The thickness of the second drip-proof member 92 is substantially fixed, and is disposed so as to have a cross section in an inverted L shape. One end portion of the inner peripheral surface of the second drip-proof member 92 contacts and is fixed to the lens holding frame F1, and the other end portion is fixed to the object side surface of the lead screw support mechanism 304 fixed to the second fixed cylinder member 13b.

[0072] With the above-described drip-proof structure 90, when the optical system block portion 100 is moved from, for example, the closest state to the infinity state, the water-repellent property of the first drip-proof member 91 suppresses the intrusion of water droplets adhering to the lens holding frame F1 into the inside of the lens barrel 2. In addition, even when water droplets enter the inside of the lens barrel 2 ( Figure 10 the space S in (A)), the second drip-proof member 92 can prevent the water droplets from entering deeper inside the lens barrel 2 (on the image side with respect to the lead screw support mechanism 304 and the second fixed cylinder member 13b). The water droplets that have entered the space S are absorbed by the first drip-proof member 91 having water absorbency, and evaporate from the first drip-proof member 91 over time. In addition, even if there are water droplets that are not absorbed by the first drip-proof member 91, the second drip-proof member 92 can reliably prevent intrusion into the inside of the lens barrel 2.

[0073] Thus, in the drip-proof structure 90, for example, as Figure 10As in the comparative example shown in (B), for example, the same level of anti-drip performance as that of the anti-drip structure in which the non-woven fabric structure 991 is flattened and brought into contact with the lens holding frame F1 can be obtained. If the non-woven fabric structure 991 is squeezed to bring it into contact with the lens holding frame F1, when the optical system block portion 100 moves in the optical axis OA direction, friction is generated between the non-woven fabric structure 991 and the lens holding frame F1, which becomes a driving resistance and applies a load to the stepping motor 301. If a load is applied to the stepping motor 301, even if the stepping motor 301 is driven by a specified amount, there may be a case where the moving amount of the optical system block portion 100 cannot accurately correspond to the specified amount due to the driving resistance. In the present embodiment, since the first anti-drip member 91 does not come into contact with the lens holding frame F1, the load applied to the stepping motor 301 can be reduced. Thereby, the position control accuracy of the optical system block portion 100 can be improved.

[0074] In addition, flattening the non-woven fabric structure 991 means that the height of the cross-section of the non-woven fabric structure 991 in the state of being assembled to the lens barrel is smaller than the height of the cross-section of the non-woven fabric structure 991 in the state of not being assembled to the lens barrel.

[0075] As described in detail above, according to the present embodiment, the lens barrel 2 includes: an optical system block portion 100 that holds the lens groups L1 and L2; a drive mechanism 300 that includes a lead screw 302 and drives the optical system block portion 100 in the optical axis OA direction; and a first fixed cylinder member 13a that has first guide grooves 11a to third guide grooves 11c for guiding the drive of the optical system block portion 100 in the optical axis OA direction. In a plane orthogonal to the optical axis OA, the first guide groove 11a and the second guide groove 11b among the first guide grooves 11a to third guide grooves 11c are arranged on a second straight line LN2 that is orthogonal to a first straight line LN1 passing through the axis AX1 of the lead screw 302 and the optical axis OA and passes through the optical axis OA.

[0076] Thus, as described with reference to Figure 9 of (A) and Figure 9 of (B), the driving accuracy of the optical system block portion 100 can be improved, and the accuracy error can be further reduced. Therefore, the position control accuracy of the optical system block portion 100 can be improved.

[0077] In addition, according to the present embodiment, the first guide grooves 11a to third guide grooves 11c are linear grooves arranged along the optical axis OA direction, and the optical system block portion 100 has front protrusions 112a to 112c and rear protrusions 113a to 113c that protrude radially outward and are guided along the linear grooves. Thereby, the optical system block portion 100 can be guided in the optical axis OA direction.

[0078] In addition, according to the present embodiment, the optical system block portion 100 includes front bearings 102a to 102c that can rotate about the centers of the front protrusions 112a to 112c and rear bearings 103a to 103c that can rotate about the centers of the rear protrusions 113a to 113c.

[0079] Thereby, the load applied to the stepping motor 301 when the optical system block portion 100 moves in the optical axis OA direction can be reduced, and thus the position control accuracy of the optical system block portion 100 can be improved.

[0080] In addition, according to the present embodiment, the first guide groove 11a to the third guide groove 11c include the first guide groove 11a and the second guide groove 11b disposed on the second straight line LN2, and the third guide groove 11c different from the first guide groove 11a and the second guide groove 11b. Since the optical system block portion 100 is supported by three guide members, the strength of the lens barrel 2 against impact can be improved as compared with the case where, for example, the optical system block portion 100 is supported by two or less guide members.

[0081] In addition, the third guide groove 11c is disposed on the first straight line LN1. That is, the third guide groove 11c is disposed at a position opposite to the lead screw 302 (disposed 180° apart) in a plane orthogonal to the optical axis OA. The third guide groove 11c intervenes Figure 9 the yaw-direction wobbling in (A), but due to the positional relationship of the fulcrum, it has no influence on the driving performance near the optical axis center. In addition, in the driving performance of the peripheral portion far from the optical axis, since the orientation of the third guide groove 11c portion is in the Figure 9 vertical direction in (A), only the minimum looseness is required and the yaw-direction wobbling is also small, so it does not affect the driving accuracy of the optical system block portion 100. Therefore, the optical system block portion 100 can be supported without significantly affecting the driving accuracy of the optical system block portion 100, and the strength of the lens barrel 2 against impact can be improved.

[0082] In addition, in the present embodiment, when the lead screw 302 rotates, the annular member 303a moves in the axial direction of the lead screw 302 while rotating, so that the friction generated between the annular member 303a and the lead screw 302 becomes rolling friction. Thereby, the load applied to the stepping motor 301 when moving the optical system block portion 100 in the axial direction of the lead screw 302 can be reduced, and thus the position control accuracy of the optical system block portion 100 can be improved.

[0083] In addition, according to the present embodiment, the lens barrel 2 includes: a lens holding frame F1 and a second fixed barrel member 13b that move relative to each other in the optical axis OA direction; and a first drip-proof member 91 and a second drip-proof member 92 that are provided in the gap between the lens holding frame F1 and the second fixed barrel member 13b and communicate the outside and the inside of the lens barrel 2. In other words, the lens barrel 2 includes: a lens holding frame F1 that holds the lens group L1; a second fixed barrel member 13b that is disposed radially outside the lens holding frame F1, and the position of the second fixed barrel member 13b in the optical axis OA direction changes relative to the lens holding frame F1; and a first drip-proof member 91 and a second drip-proof member 92 that are disposed in the gap between the lens holding frame F1 and the second fixed barrel member 13b.

[0084] Thereby, it is possible to suppress water droplets from entering the inside of the lens barrel 2 from the outside of the lens barrel 2 through the gap between the lens holding frame F1 and the second fixed barrel member 13b. In addition, it is possible to suppress light from entering through the gap between the lens holding frame F1 and the second fixed barrel member 13b.

[0085] In addition, in the present embodiment, the water repellency of the first drip-proof member 91 is higher than that of the second drip-proof member 92. Thereby, it is possible to suppress the intrusion of water droplets by the water repellency of the first drip-proof member 91.

[0086] In addition, in the present embodiment, the first drip-proof member 91 and the second drip-proof member 92 are arranged in the optical axis OA direction, and the first drip-proof member 91 is disposed closer to the object side than the second drip-proof member 92. That is, the second drip-proof member 92 is disposed closer to the image plane side than the first drip-proof member 91. Thereby, even when there are water droplets that are not completely prevented from entering by the first drip-proof member 91, it is possible to suppress the further intrusion of the water droplets into the lens barrel 2 by the second drip-proof member 92.

[0087] In addition, in the present embodiment, at least a part of the thickness T1 of the first drip-proof member 91 in a plane orthogonal to the optical axis is larger than at least a part of the thickness T2 of the second drip-proof member 92. By making the thickness T1 of the first drip-proof member 91 disposed on the object side larger than the thickness T2 of the second drip-proof member 92, it is possible to effectively suppress the intrusion of water droplets from the object side of the gap between the lens holding frame F1 and the second fixed barrel member 13b.

[0088] In addition, in the present embodiment, a gap is provided between the first drip-proof member 91 and the lens holding frame F1. Thereby, compared with the case where the first drip-proof member 91 is in contact with the lens holding frame F1, the load applied to the stepping motor 301 can be reduced, and thus the position control accuracy of the optical system block portion 100 can be improved.

[0089] In addition, in the above-described embodiment, the stepping motor 301 is used as the drive source for rotating the drive screw 302, but for example, an ultrasonic motor, a VCM motor, etc. may be used instead of the stepping motor 301. Further, a position detection unit may be provided for feedback control.

[0090] In addition, in the above-described embodiment, the first guide groove to the third guide groove 11a to 11c are engaged with the first groove engaging portion 101a to the third groove engaging portion 101c, but as the straight-line guiding mechanism, a combination of a shaft-shaped guide rod and an engaging portion engaged with the guide rod may be used. In this case, two or more straight-line guiding mechanisms are sufficient, and two straight-line guiding mechanisms may be respectively arranged on the second straight line LN2.

[0091] In addition, in the above-described embodiment, in the first groove engaging portion 101a to the third groove engaging portion 101c, the front bearings 102a to 102c and the rear bearings 103a to 103c are engaged with the first guide groove 11a to the third guide groove 11c, but the front bearings 102a to 102c and the rear bearings 103a to 103c may be omitted, and the front protrusions 112a to 112c and the rear protrusions 113a to 113c may be engaged with the first guide groove 11a to the third guide groove 11c. Further, either one of the front bearing 102a and the rear bearing 103a may be omitted, either one of the front bearing 102b and the rear bearing 103b may be omitted, and either one of the front bearing 102c and the rear bearing 103c may be omitted. In particular, even when at least one of the front bearing 102c and the rear bearing 103c is omitted, since the first guide groove 11a and the second guide groove 11b are arranged on the second straight line LN2, the effect of suppressing the tipping of the moving portion 20 can be maintained.

[0092] In addition, in the above-described embodiment, the first guide groove 11a and the second guide groove 11b are arranged on the second straight line LN2, but as long as it is within a specified range, they may be arranged at positions deviated from the second straight line LN2. For example, in a plane orthogonal to the optical axis OA, at least a part of the first guide groove 11a may be arranged on the second straight line LN2, and at least a part of the second guide groove 11b may be arranged on the second straight line LN2. Specifically, in a plane orthogonal to the optical axis OA, the angle formed by the straight line connecting the optical axis OA and the center of the first guide groove 11a and the second straight line LN2 may be within the range of ±15°. In addition, the angle formed by the straight line connecting the optical axis OA and the center of the second guide groove 11b and the second straight line LN2 may be within the range of ±15°.

[0093] In addition, in the above-described embodiment, the third guide groove 11c may also be omitted. Further, although the third guide groove 11c is disposed on the first straight line LN1, it may also be disposed at a position deviated from the first straight line LN1 as long as it is within a specified range. For example, in a plane orthogonal to the optical axis OA, at least a part of the third guide groove 11c may be disposed on the first straight line LN1. Specifically, in a plane orthogonal to the optical axis OA, the angle formed by the straight line connecting the optical axis OA and the center of the third guide groove 11c and the first straight line LN1 may be within the range of ±15°.

[0094] In addition, in the above-described embodiment, the drip-proof structure 90 includes two drip-proof members, i.e., the first drip-proof member 91 and the second drip-proof member 92, but it may also include three or more drip-proof members.

[0095] In addition, in the above-described embodiment, the first drip-proof member 91 is disposed closer to the object side than the second drip-proof member 92 in the direction of the optical axis OA, but the second drip-proof member 92 may also be disposed closer to the object side than the first drip-proof member 91.

[0096] In addition, in the above-described embodiment, the case where the focusing method of the lens barrel 2 is the overall extension method has been described. However, even if the focusing method of the lens barrel 2 is a method other than the overall extension method, the structure of the present embodiment can be adopted. For example, even if the lens groups L1 and L2 included in the optical system block portion 100 are the internal focusing method as an intermediate portion in the photographing optical system, the optical system block portion 100 can be supported by the first guide groove 11a to the third guide groove 11c.

[0097] In addition, in the above-described embodiment, the first drip-proof member 91 and the second drip-proof member 92 are provided between the lens holding frame F1 that can relatively move in the direction of the optical axis OA and does not relatively rotate in the circumferential direction and the second fixed cylinder member 13b, but it is not limited thereto. For example, the drip-proof structure 90 can be applied to the gap between two frames that can relatively move in the direction of the optical axis OA and relatively rotate in the circumferential direction. For example, the gap between the lens holding frame and the focusing operation ring.

[0098] In addition, the stepping motor 301 is Figure 8 disposed above the optical axis center, but can be appropriately changed according to the positional relationship with other components in the lens barrel 2. For example, the stepping motor 301 is preferably disposed at a position where it does not interfere with the electrical contacts in the lens barrel 2 and the substrate disposed in the direction orthogonal to the optical axis.

[0099] The above-described embodiment is a preferred example. However, it is not limited thereto, and various modifications can be made without departing from the gist, and any constituent elements can also be combined.

[0100] Description of Reference Numerals

[0101] 1 Camera

[0102] 2 Lens Barrel

[0103] 13 Fixed Tube

[0104] 13a First Fixed Tube Member

[0105] 13b Second Fixed Tube Member

[0106] 11a~11c First~Third Guide Grooves

[0107] 20 Moving Portion

[0108] 82 Second Biasing Member

[0109] 91 First Anti-Drip Member

[0110] 92 Second Anti-Drip Member

[0111] 100 Optical System Block Portion

[0112] 101a~101c First~Third Groove Engaging Portions

[0113] 102a~102c Front Bearings

[0114] 103a~103c Rear Bearings

[0115] 112a~112c Front Protrusions

[0116] 113a~113c Rear Protrusions

[0117] 300 Driving Mechanism

[0118] 301 Stepper Motor

[0119] 302 Lead Screw

[0120] 303a Ring Member

[0121] L1、L2 Lens Groups

[0122] F1 Lens Holding Frame

[0123] LN1 First Straight Line

[0124] LN2 Second Straight Line

[0125] OA Optical Axis

[0126] AX1 Axis

Claims

1. A lens barrel, wherein, the lens barrel includes: a first frame that holds a lens; a driving unit that includes a driving shaft and drives the first frame in the optical axis direction; and a second frame that has at least two guiding portions that guide the driving of the first frame in the optical axis direction, in a plane orthogonal to the optical axis, at least one of the at least two guiding portions is disposed on a second straight line that is orthogonal to a first straight line passing through the driving shaft and the optical axis and passes through the optical axis.

2. The lens barrel according to claim 1, wherein, at least one of the at least two guiding portions has a linear groove disposed along the optical axis direction, the first frame has a protrusion that protrudes outward from the outer periphery and is guided along the linear groove.

3. The lens barrel according to claim 2, wherein, a bottom surface on the object side in the optical axis direction of the linear groove is located on the outer diameter side relative to a bottom surface on the image side of the linear groove.

4. The lens barrel according to claim 2, wherein, the first frame has a rotating portion that is provided on the protrusion and is capable of rotating.

5. The lens barrel according to claim 4, wherein, the rotating portion has: an inner ring that is fixed to the protrusion; and an outer ring that is capable of relative rotation with respect to the inner ring, an outer peripheral surface of the outer ring abuts against the linear groove.

6. The lens barrel according to claim 1, wherein, the at least two guiding portions include: a first guiding portion and a second guiding portion that are disposed on the second straight line; and a third guiding portion that is different from the first guiding portion and the second guiding portion.

7. The lens barrel according to claim 6, wherein, the third guiding portion is disposed on the first straight line.

8. The lens barrel according to claim 1, wherein, the driving unit has: a lead screw; a ring-shaped member; a moving member that holds the ring-shaped member to be rotatable and moves in the axial direction of the lead screw as the lead screw rotates; and a biasing portion that biases the ring-shaped member toward the lead screw in a direction orthogonal to the axial direction of the lead screw.

9. A lens barrel, wherein, the lens barrel includes: a first frame that holds a lens; a driving unit that includes a driving shaft and drives the first frame in the optical axis direction; a second frame that has at least two guiding portions that guide the driving of the first frame in the optical axis direction; an inner ring that is fixed to the first frame; and an outer ring that is capable of relative rotation with respect to the inner ring, an outer peripheral surface of the outer ring abuts against the guiding portion.

10. A lens barrel that has a first frame and a second frame that relatively move in the optical axis direction, wherein, the lens barrel includes at least two drip-proof members that are provided in a gap that connects the outside and the inside of the lens barrel between the first frame and the second frame.

11. The lens barrel according to claim 10, wherein, the first frame holds a lens, the second frame is disposed on the outer peripheral side of the first frame.

12. The lens barrel according to claim 10 or 11, wherein, the at least two drip-proof members include a first drip-proof member and a second drip-proof member, The hydrophobicity of the first drip-proof member is higher than that of the second drip-proof member.

13. The lens barrel according to claim 12, wherein the first drip-proof member and the second drip-proof member are arranged in the optical axis direction, and the first drip-proof member is disposed closer to the object side than the second drip-proof member.

14. The lens barrel according to claim 12, wherein the first drip-proof member and the second drip-proof member are arranged in the optical axis direction, and the second drip-proof member is disposed closer to the object side than the first drip-proof member.

15. The lens barrel according to claim 12, wherein the first drip-proof member and the second drip-proof member are arranged in the optical axis direction, and the thickness of at least a part of the first drip-proof member is larger than the thickness of at least a part of the second drip-proof member.

16. The lens barrel according to claim 12, wherein the first frame is movable relative to the second frame in the optical axis direction, and the first frame and the second frame do not rotate relative to each other in the circumferential direction.

17. The lens barrel according to claim 12, wherein a gap is provided between the first drip-proof member and the first frame.

18. An imaging device including the lens barrel according to any one of claims 1 to 17.

Images