Lens barrel

Abstract

To provide a lens barrel which offers good optical performance.SOLUTION: A lens barrel is provided, comprising a first lens holding frame for holding a firsts lens, a first guide shaft for guiding the first lens holding frame in an optical axis direction, a contact member in contact with the first guide shaft, and a spring member configured to be in contact with the first lens holding member to press the contact member toward the first guide shaft.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a lens barrel. [Background technology]

[0002] Lens barrels are required to have good optical performance (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-168492 Summary of the Invention

[0004] According to a first aspect, a lens barrel includes a first lens holding frame that holds a first lens, a first guide shaft that guides the first lens holding frame in the optical axis direction, a contact member that contacts the first guide shaft, and a biasing member that contacts the first lens holding frame and biases the contact member toward the first guide shaft.

[0005] According to a second aspect, an imaging device includes the above-described lens barrel.

[0006] The configurations of the embodiments described below may be modified as appropriate, and at least a portion of the configuration may be replaced with other components. Furthermore, components that are not particularly limited in terms of their placement may be placed in any position that can achieve their function, not limited to the placement disclosed in the embodiments. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram showing a camera including a lens barrel and a camera body according to an embodiment. [Figure 2] FIG. 2 is a perspective view of the movable barrel as seen from the camera body side. [Figure 3]3(A) and 3(B) are schematic perspective views of the seventh lens retaining frame, and FIG. 3(C) is a cross-sectional view for explaining the engagement between the seventh lens retaining frame and the guide bar. [Figure 4] FIG. 4(A) is a schematic perspective view of the eighth lens holding frame, and FIG. 4(B) is a cross-sectional view for explaining the engagement between the eighth lens holding frame and the guide bar. [Figure 5] Figure 5(A) is a view of the movable barrel with the fixed part removed, viewed from the camera body side, and Figure 5(B) is an enlarged view of the first engagement part and its vicinity in Figure 5(A), with a portion shown in cross section. [Figure 6] 6(A) and 6(B) are perspective views showing the seventh lens retaining frame, the eighth lens retaining frame, the first drive source unit, and the second drive source unit. [Figure 7] Figure 7(A) is a plan view of the ninth lens group and the ninth lens holding frame as seen from the subject side, Figure 7(B) is a perspective view of the ninth lens group and the ninth lens holding frame as seen from the subject side, and Figure 7(C) is a perspective view of the ninth lens group and the ninth lens holding frame as seen from the camera body side. [Figure 8] FIG. 8(A) is a diagram for explaining the relationship between the seventh lens holding frame and the ninth lens group when the seventh lens group is closest to the ninth lens group, and FIG. 8(B) is a cross-sectional view taken along line BB in FIG. 8(A). [Figure 9] FIG. 9 is a diagram illustrating the length of the guide bar and the engagement length between the guide bar and the first engagement portion in one embodiment. [Figure 10] 10(A) and 10(B) are diagrams for explaining the size of the movable barrel, the length of the guide bar, and the engagement length between the guide bar and the first engagement portion when the ninth lens group is circular. DETAILED DESCRIPTION OF THE INVENTION

[0008] A lens barrel 100 according to one embodiment will be described in detail below with reference to the drawings. Note that in each drawing, some elements may be omitted for ease of understanding.

[0009] 1 is a diagram showing a camera 1 equipped with a lens barrel 100 according to this embodiment and a camera body 101. In this embodiment, the lens barrel 100 is detachable from the camera body 101 by a lens mount LM. Although detachable, the lens barrel 100 and the camera body 101 may be integrated.

[0010] The camera body 101 is equipped with an image sensor (not shown) that captures a subject image formed by a group of lenses arranged inside the lens barrel 100 and converts the image into an electrical signal.

[0011] As shown in Fig. 1, the lens barrel 100 according to this embodiment includes a first lens group L1 to a ninth lens group L9 arranged in sequence along a common optical axis OA. The first lens group L1 to the ninth lens group L9 are held in first lens holding frames F1 to F9, respectively. In the lens barrel 100 according to this embodiment, the seventh lens group L7 and the eighth lens group L8 are each focus lens groups. Each lens group may be composed of a single lens or multiple lenses.

[0012] Lens barrel 100 also has a first guide bar 27, a second guide bar 28 (not shown in FIG. 1), and a rotation restriction bar 29. First guide bar 27 guides seventh lens retaining frame F7 in the direction of the optical axis OA, and second guide bar 28 guides eighth lens retaining frame F8 in the direction of the optical axis OA. Rotation restriction bar 29 restricts rotation of seventh lens retaining frame F7 about the first guide bar 27 as an axis and rotation of eighth lens retaining frame F8 about the second guide bar 28 as an axis. First guide bar 27, second guide bar 28, and rotation restriction bar 29 are fixed to movable barrel 110, which moves in the direction of the optical axis OA when the user operates the zoom operation ring.

[0013] Fig. 2 is a perspective view of the movable barrel 110 as seen from the camera body 101 side. As shown in Fig. 2, the movable barrel 110 includes a barrel portion 112 and a fixed portion 113. The movable barrel 110 also includes a cam pin 111 on the outer peripheral surface of the barrel portion 112 that protrudes in a direction intersecting with the optical axis OA.

[0014] 1, lens barrel 100 includes fixed barrel 120, which is positioned radially outward of movable barrel 110, and cam barrel 130, which is positioned radially outward of fixed barrel 120 and is rotatable about optical axis OA. Cam barrel 130 rotates about optical axis OA in conjunction with the rotation of the zoom operation ring.

[0015] A linear groove (not shown in FIG. 1) extending in the direction of the optical axis OA is formed in the fixed barrel 120, and a cam groove 131 is formed in the cam barrel 130. The cam pin 111 of the movable barrel 110 passes through the linear groove of the fixed barrel 120 and is slidably fitted into the cam groove 131 of the cam barrel 130. As a result, when the cam barrel 130 rotates around the optical axis OA in conjunction with the rotation of the zoom operation ring, the movable barrel 110 moves linearly in the direction of the optical axis OA along the cam groove 131 and the linear groove. The cam pin 111 may be, for example, a cam follower or the like.

[0016] In this way, in lens barrel 100 according to the present embodiment, the position of movable barrel 110 in the optical axis OA direction relative to ninth lens group L9 changes. Because first guide bar 27, second guide bar 28, and rotation restriction bar 29 are fixed to movable barrel 110, when movable barrel 110 moves in the optical axis OA direction, the positions of first guide bar 27, second guide bar 28, and rotation restriction bar 29 relative to ninth lens group L9 also change.

[0017] Next, the configurations of the seventh lens retaining frame F7 and the eighth lens retaining frame F8 will be described. Figures 3(A) and 3(B) are schematic perspective views of the seventh lens retaining frame F7, and Figure 3(C) is a cross-sectional view for explaining the engagement between the seventh lens retaining frame F7 and the first guide bar 27. Figure 4(A) is a schematic perspective view of the eighth lens retaining frame F8, and Figure 4(B) is a cross-sectional view for explaining the engagement between the eighth lens retaining frame F8 and the second guide bar 28.

[0018] First, the seventh lens retaining frame F7 will be described. As shown in Figures 3(A) and 3(B), the seventh lens retaining frame F7 has a cylindrical portion 30 that retains the seventh lens group L7, and the cylindrical portion 30 has a first engaging portion 31 that engages with the first guide bar 27 and a first protrusion 32 that engages with the rotation restricting bar 29 on its outer periphery.

[0019] 3(B) and 3(C), first engagement portion 31 has two first plate-shaped portions 311a and 311b that are spaced apart in the direction of optical axis OA and are substantially perpendicular to central axis AX1 of first guide bar 27. First plate-shaped portions 311a and 311b are formed with holes 315a and 315b, respectively, through which first guide bar 27 is inserted.

[0020] 3(C), a biasing mechanism 50 is provided inside the first engagement portion 31. The biasing mechanism 50 includes a bearing 51, a bearing support portion 52, and a compression spring 53.

[0021] The bearing 51 is, for example, a ball bearing having a cylindrical outer shape. The bearing 51 is supported by a bearing support portion 52 and comes into contact with the first guide bar 27. The bearing support portion 52 does not come into contact with the first guide bar 27. In other words, a portion of the bearing 51 is located outward from the bearing support portion 52 in the radial direction of a circle centered on the optical axis OA. Alternatively, a portion of the bearing 51 protrudes further from the bearing support portion 52 toward the first guide bar 27. Note that the bearing 51 is not limited to a ball bearing and may be a general sliding bearing. The bearing 51 may be, for example, a roller bearing or a free ball bearing.

[0022] One end of compression spring 53 contacts first engagement portion 31, and the other end contacts bearing support portion 52. That is, compression spring 53 is provided between first engagement portion 31 (seventh lens retaining frame F7) and bearing support portion 52. Compression spring 53 urges bearing 51 toward first guide bar 27 via bearing support portion 52. More specifically, compression spring 53 urges bearing support portion 52 toward first guide bar 27 (in the direction indicated by arrow A1 in FIG. 3(C)). As a result, bearing 51 is also urged toward first guide bar 27 (see arrow A6) and pressed against first guide bar 27. As a result, first engagement portion 31 is pressed against first guide bar 27 (see arrow A7). More specifically, the inner circumferential surfaces of holes 315a and 315b are pressed against first guide bar 27. This reduces rattle between first guide bar 27 and holes 315a, 315b (seventh lens retaining frame F7) of first engagement portion 31. Note that instead of compression spring 53, a torsion spring or an elastic body such as rubber may be used. Also, a leaf spring may be used. Also, bearing 51 may be biased toward first guide bar 27 without using bearing support portion 52.

[0023] A more detailed explanation will be given below of the direction of the biasing force of the compression spring 53. Fig. 5(A) is a view of the movable barrel 110 from which the fixed part 113 has been removed, as seen from the camera body 101 side, and Fig. 5(B) is an enlarged, partially cross-sectional view of the vicinity of the first engagement part 31 in Fig. 5(A).

[0024] As shown in Fig. 5(A), first guide bar 27 and second guide bar 28 are arranged symmetrically with respect to a line SL1 connecting central axis AX3 of rotation restriction bar 29 and optical axis OA in a plane perpendicular to optical axis OA. The cross-sectional view of Fig. 1 is a cross-sectional view taken along line AA in Fig. 5(A).

[0025] 5(B), bearing 51 is disposed on a straight line SL2 connecting optical axis OA and center axis AX1 of first guide bar 27 in a plane perpendicular to optical axis OA. More specifically, bearing 51 is disposed so that its center axis AX4 is substantially perpendicular to line SL2 in a plane perpendicular to optical axis OA. In other words, bearing 51 is disposed so that a line passing through point of contact CP1 between bearing 51 and first guide bar 27 and representing the diameter of bearing 51 is substantially parallel to line SL2 in a plane perpendicular to optical axis OA.

[0026] As shown by arrow A2 in Fig. 5(B), bearing 51 is biased by compression spring 53 toward first guide bar 27 (outside) in a direction substantially parallel to straight line SL2. As a result, first engagement portion 31 is pressed against first guide bar 27 in a direction substantially parallel to straight line SL2, as shown by arrow A3 in Fig. 5(B). This reduces play between first guide bar 27 and holes 315a, 315b of first engagement portion 31. Furthermore, because the direction in which first engagement portion 31 is pressed against first guide bar 27 is substantially parallel to straight line SL2, it is possible to prevent the central axis of seventh lens group L7 from deviating from optical axis OA.

[0027] Next, the eighth lens retaining frame F8 will be described. As shown in Fig. 4(A), the eighth lens retaining frame F8 has a cylindrical portion 40 that retains the eighth lens group L8, and the cylindrical portion 40 has, on its outer periphery, a second engaging portion 41 that engages with the second guide bar 28 and a second protrusion 42 that engages with the rotation restricting bar 29.

[0028] Sheet S1 is disposed behind eighth lens group L8 in the direction of optical axis OA (toward camera body 101). Sheet S1 has an opening in the shape of a circle with the top and bottom notched in a plane perpendicular to optical axis OA, and prevents light that enters lens barrel 100 from the subject side and is reflected by first guide bar 27, second guide bar 28, and rotation restriction bar 29 from entering the imaging range of the image sensor.

[0029] 4(A) and 4(B), the second engagement portion 41 has two second plate-shaped portions 411a and 411b that are spaced apart in the direction of the optical axis OA and are substantially perpendicular to the central axis AX2 of the second guide bar 28. The second plate-shaped portions 411a and 411b are formed with holes 415a and 415b, respectively, through which the second guide bar 28 is inserted.

[0030] 4(B), a biasing mechanism 50 is provided inside the second engagement portion 41. The configuration of the biasing mechanism 50 is similar to that of the biasing mechanism 50 provided inside the first engagement portion 31, and therefore a detailed description thereof will be omitted.

[0031] As shown in FIG. 4(B), compression spring 53 biases bearing support portion 52 toward second guide bar 28 (in the direction indicated by arrow A1 in FIG. 4(B)). As a result, bearing 51 is also biased toward second guide bar 28 (see arrow A6) and pressed against second guide bar 28. As a result, second engagement portion 41 is pressed against second guide bar 28 (see arrow A7). More specifically, the inner circumferential surfaces of holes 415a and 415b are pressed against second guide bar 28. This reduces rattling between second guide bar 28 and holes 415a and 415b (eighth lens retaining frame F8) of second engagement portion 41.

[0032] Although a cross section is not shown in FIG. 5B, the bearing 51 in the second engagement portion 41 is disposed on a line SL3 connecting the optical axis OA and the center axis AX2 of the second guide bar 28 in a plane perpendicular to the optical axis OA. As indicated by arrow A4 in FIG. 5B, the bearing 51 in the second engagement portion 41 is biased by a compression spring 53 toward the second guide bar 28 (outside) in a direction substantially parallel to the line SL3. As a result, the second engagement portion 41 is pressed against the second guide bar 28 in a direction substantially parallel to the line SL3, as indicated by arrow A5 in FIG. 5B. This reduces play between the second guide bar 28 and the holes 415a, 415b in the second engagement portion 41. Furthermore, because the direction in which the second engagement portion 41 is pressed against the second guide bar 28 is substantially parallel to the line SL3, it is possible to prevent the center axis of the eighth lens group L8 from deviating from the optical axis OA.

[0033] Next, the driving of the seventh lens retaining frame F7 and the eighth lens retaining frame F8 will be described. The seventh lens retaining frame F7 is driven by a first drive source unit 70, and the eighth lens retaining frame F8 is driven by a second drive source unit 80. Figures 6(A) and 6(B) are perspective views showing the seventh lens retaining frame F7, the eighth lens retaining frame F8, the first drive source unit 70, and the second drive source unit 80.

[0034] When a user rotates the focus operation ring, an encoder (not shown) detects the rotation of the focus operation ring, and a control unit (not shown) drives a stepping motor 701 of the first drive source unit 70 and a stepping motor 801 of the second drive source unit 80 (described later) in accordance with the amount of rotation of the focus operation ring to move the seventh lens retaining frame F7 and the eighth lens retaining frame F8, respectively. Also during autofocus, the control unit (not shown) drives the stepping motor 701 of the first drive source unit 70 and the stepping motor 801 of the second drive source unit 80.

[0035] The first drive source unit 70 has a stepping motor 701, a lead screw 702, a rack 703, and a mounting member 704. Instead of the first drive source unit 70, a voice coil motor, an ultrasonic motor, or the like may be used.

[0036] The lead screw 702 is directly connected to the output shaft of the stepping motor 701 and is driven to rotate by the stepping motor 701 .

[0037] A stepping motor 701 is fixed to the mounting member 704. The mounting member 704 also rotatably supports a lead screw 702. A plurality of holes are formed in the mounting member 704, and the first drive source unit 70 is fixed to the movable barrel 110 by fixing the mounting member 704 to the movable barrel 110 with screws 705 or the like (see FIG. 2).

[0038] The rack 703 has a connecting portion that connects with the first engagement portion 31 and a contact portion that comes into contact with the lead screw 702. The contact portion has a thread that is complementary in shape to the thread of the lead screw 702. As a result, when the lead screw 702 is rotated by the stepping motor 701, the rack 703 moves. As the rack 703 moves, the first engagement portion 31 that is connected to the connecting portion of the rack 703 is guided by the first guide bar 27 and moves linearly in the direction of the optical axis OA. As a result, when the lead screw 702 is driven to rotate, the seventh lens retaining frame F7 can move linearly in the direction of the optical axis OA.

[0039] The second drive source unit 80 has a stepping motor 801, a lead screw 802, a rack 803, and a mounting member 804. Instead of the second drive source unit 80, a voice coil motor, an ultrasonic motor, or the like may be used.

[0040] The lead screw 802 is directly connected to the output shaft of the stepping motor 801 and is driven to rotate by the stepping motor 801 .

[0041] A stepping motor 801 is fixed to the mounting member 804. The mounting member 804 also rotatably supports a lead screw 802. A plurality of holes are formed in the mounting member 804, and the second drive source unit 80 is fixed to the movable barrel 110 by fixing the mounting member 804 to the movable barrel 110 with screws 805 or the like (see FIG. 2).

[0042] Similarly, the rack 803 has a connecting portion that connects with the second engagement portion 41 and a contact portion that comes into contact with the lead screw 802. The contact portion has a thread that is complementary in shape to the thread of the lead screw 802. As a result, when the lead screw 802 is rotated by the stepping motor 801, the rack 803 moves. As the rack 803 moves, the second engagement portion 41, which is connected to the connecting portion of the rack 803, is guided by the second guide bar 28 and moves linearly in the direction of the optical axis OA. As a result, when the lead screw 802 is driven to rotate, the eighth lens retaining frame F8 can move linearly in the direction of the optical axis OA.

[0043] Next, the configuration of the ninth lens group L9 and the ninth lens retaining frame F9 will be described. Fig. 7(A) is a plan view of the ninth lens group L9 and the ninth lens retaining frame F9 as seen from the subject side, Fig. 7(B) is a perspective view of the ninth lens group L9 and the ninth lens retaining frame F9 as seen from the subject side, and Fig. 7(C) is a perspective view of the ninth lens group L9 and the ninth lens retaining frame F9 as seen from the camera body 101 side. Note that in Fig. 7(A), the outer periphery of the ninth lens group L9 is indicated by a dotted line.

[0044] 7A, the ninth lens group L9 has a planar shape in a plane perpendicular to the optical axis OA that is a circle with the top and bottom notched (an oval shape or a racetrack shape). That is, the outer periphery of the ninth lens group L9 has two opposing arc-shaped outer peripheries 61 and a linear outer periphery 62 connecting the arc-shaped outer peripheries.

[0045] Sheets S2 and S3 are disposed in front of and behind ninth lens group L9 in the direction of optical axis OA. Each of sheets S2 and S3 has an opening shaped like a circle with the top and bottom notched in a plane perpendicular to optical axis OA, and prevents light that enters lens barrel 100 from the subject side and is reflected by first guide bar 27, second guide bar 28, and rotation restriction bar 29 from entering the imaging range of the image sensor.

[0046] In this embodiment, the ninth lens group L9 has a circular shape with the top and bottom notched, which creates spaces above and below the ninth lens group L9, allowing part of the seventh lens frame F7 and part of the eighth lens frame F8 to fit into these spaces.

[0047] Fig. 8(A) is a diagram for explaining the relationship between the seventh lens holding frame F7 and the ninth lens group L9 when the seventh lens group L7 is closest to the ninth lens group L9, and Fig. 8(B) is a cross-sectional view taken along line BB in Fig. 8(A). Note that Fig. 8(A) shows a state in which the zoom position is at the wide end and the seventh lens group L7 and the eighth lens group L8 are at the closest end.

[0048] 8A, in this embodiment, when the seventh lens group L7 and the ninth lens group L9 are closest to each other, a portion of the first engagement portion 31 of the seventh lens retaining frame F7 is located closer to the camera body 101 (image side) than the surface of the ninth lens group L9 closest to the subject (foreground) in the optical axis OA direction. More specifically, when the seventh lens group L7 and the ninth lens group L9 are closest to each other, a portion of the first engagement portion 31 of the seventh lens retaining frame F7 is located closer to the camera body 101 than the surface of the ninth lens group L9 closest to the subject or the end of the ninth lens retaining frame F9 closest to the subject in a region R1 between the outer periphery of the ninth lens retaining frame F9 and the outer periphery of the ninth lens group L9.

[0049] In other words, when the seventh lens group L7 and the ninth lens group L9 are closest to each other, the first engagement portion 31 and the ninth lens group L9 overlap in the radial direction of a circle centered on the optical axis OA, as shown in Fig. 8(B). The same applies to the eighth lens group L8 and the eighth lens retaining frame F8.

[0050] Next, the advantages of forming the planar shape of the ninth lens group L9 into a shape with the top and bottom of a circle cut out (an oval shape or a racetrack shape) will be described. FIG. 9 is a diagram for explaining the length of the first guide bar 27 and the engagement length between the first guide bar 27 and the first engagement portion 31 in this embodiment, and FIGS. 10(A) and 10(B) are diagrams for explaining the size of the movable barrel 110, the length of the first guide bar 27, and the engagement length between the first guide bar 27 and the first engagement portion 31 when the planar shape of the ninth lens group L9 is circular. Note that FIGS. 9, 10(A), and 10(B) show a state in which the seventh lens group L7 is closest to the ninth lens group L9. Note that, although the following description will focus on the first guide bar 27 and the seventh lens group L7, the same applies to the second guide bar 28 and the eighth lens group L8.

[0051] If the planar shape of the ninth lens group L9 is circular, and the diameter of the movable barrel 110 is the same as in this embodiment, the rear end of the movable barrel 110 will hit the ninth lens holding frame F9 in the direction of the optical axis OA. Here, as shown in FIG. 10(A), if the inner diameter of the fixed portion 113 is made larger than the outer diameter of the ninth lens group L9 and the diameter of the barrel portion 112 is also made larger, the rear end of the movable barrel 110 can be positioned closer to the camera body 101 than the surface of the ninth lens group L9 closest to the subject. However, in this case, the diameter of the movable barrel 110 becomes larger, resulting in an increase in the size of the lens barrel 100. Furthermore, compared to the case of FIG. 9, the first guide bar 27 and the second guide bar 28 are positioned radially outward, and the first guide bar 27 and the second guide bar 28 are spaced farther from the optical axis OA, which makes the guidance of the seventh lens group L7 and the eighth lens group L8 unstable. Furthermore, in order to prevent the rear end of the movable barrel 110 from colliding with the ninth lens retaining frame F9 without changing the size of the movable barrel 110, for example, the length of the movable barrel 110 in the optical axis OA direction is shortened as shown in Figure 10(B), which also shortens the length of the first guide bar 27.

[0052] Even if the length of the first guide bar 27 is shortened, the positional relationship between the seventh lens group L7 and the ninth lens group L9 at the infinity end and the close-up end remains unchanged, so the length of the first engagement portion 31 in the direction of the optical axis OA is also shortened. That is, the engagement length between the first engagement portion 31 and the first guide bar 27 becomes shorter, which may cause the seventh lens group L7 to tilt with respect to the optical axis direction. More specifically, if the positions of the holes 315a and 315b are shifted by a predetermined amount on a plane perpendicular to the optical axis OA, the resulting tilt will become greater as the engagement length between the first engagement portion 31 and the first guide bar 27 becomes shorter.

[0053] In this embodiment, as shown in FIG. 9, the movable barrel 110 is inserted into the space created by forming the ninth lens group L9 in the shape of a circle with the top and bottom notched, and the rear end of the movable barrel 110 (the end on the camera body 101 side (image side)) can be positioned closer to the camera body 101 than the surface of the ninth lens group L9 closest to the subject. This allows the movable barrel 110 to be positioned without increasing its size, as shown in FIG. 9. Furthermore, the length L12 of the first guide bar 27 can be made longer than when the ninth lens group L9 is circular (L14 in FIG. 10B). Furthermore, because the first guide bar 27 is longer, the engagement length L11 between the first engagement portion 31 and the first guide bar 27 (the distance between the first plate-shaped portions 311a and 311b of the first engagement portion 31) can be made longer than when the ninth lens group L9 is circular (L13 in FIG. 10B).

[0054] In this embodiment, the distance L11 between the holes 315a and 315b can be increased. This reduces the tilt of the seventh lens retaining frame F7 relative to the optical axis OA even when the positions of the holes 315a and 315b are misaligned by a certain amount on a plane perpendicular to the optical axis OA. Furthermore, the longer the distance L11 between the holes 315a and 315b, the smaller the lateral pressure exerted on the holes 315a and 315b. Specifically, when the camera 1 is facing upward or downward, the weight of the seventh lens group L7 and the seventh lens retaining frame F7 causes the seventh lens retaining frame F7 to tilt around the hole 315a or 315b, generating lateral pressure on the holes 315a and 315b. In this case, when the distance L11 is long, the lateral pressure is reduced due to the principle of leverage, reducing friction between the inner surfaces of the holes 315a and 315b and the first guide bar 27. This reduces the load on the stepping motor 701.

[0055] As described above in detail, the lens barrel 100 according to this embodiment includes the seventh lens retaining frame F7 that retains the seventh lens group L7, the first guide bar 27 that guides the seventh lens retaining frame F7 in the direction of the optical axis OA, the bearing 51 that contacts the first guide bar 27, and the compression spring 53 that contacts the seventh lens retaining frame F7 and urges the bearing 51 toward the first guide bar 27. The compression spring 53, one end of which contacts the seventh lens retaining frame F7, urges the bearing 51 toward the first guide bar 27, thereby pressing the seventh lens retaining frame F7 against the first guide bar 27. More specifically, the inner circumferential surfaces of the holes 315a and 315b of the first engagement portion 31 of the seventh lens retaining frame F7 are pressed against the first guide bar 27. This makes it possible to suppress backlash between the first guide bar 27 and the holes 315a and 315b (backlash between the first guide bar 27 and the seventh lens retaining frame F7).

[0056] Furthermore, in this embodiment, bearing 51 is pressed against first guide bar 27 by compression spring 53. This allows bearing 51 to be kept in contact with first guide bar 27, thereby suppressing backlash between first guide bar 27 and holes 315a, 315b.

[0057] Furthermore, in this embodiment, the lens barrel 100 includes a bearing support portion 52 that supports a bearing 51. A compression spring 53 is provided between the seventh lens retaining frame F7 and the bearing support portion 52, biasing the bearing support portion 52 toward the first guide bar 27. At least a portion of the bearing 51 is located outside the bearing support portion 52 in the radial direction of a circle centered on the optical axis OA. By using the bearing support portion 52, the bearing 51 can be easily biased toward the first guide bar 27. Furthermore, because the bearing support portion 52 does not contact the first guide bar 27, the torque required to move the seventh lens retaining frame F7 in the direction of the optical axis OA can be reduced compared to when the bearing support portion 52 contacts the first guide bar 27. This reduces the load on the stepping motor 701.

[0058] In this embodiment, the bearing 51 rotates in conjunction with the movement of the seventh lens retaining frame F7. This allows the seventh lens retaining frame F7 to move smoothly in the optical axis OA direction. Furthermore, the torque required to move the seventh lens retaining frame F7 in the optical axis OA direction can be reduced, thereby reducing the load on the stepping motor 701.

[0059] Furthermore, in this embodiment, bearing 51 is disposed on a line SL2 connecting central axis AX1 of first guide bar 27 and optical axis OA in a plane perpendicular to optical axis OA, thereby preventing the central axis of seventh lens group L7 from deviating from optical axis OA.

[0060] In this embodiment, the direction of the biasing force of the compression spring 53 (see arrow A2 in FIG. 5B) is substantially parallel to the straight line SL2. As a result, the seventh lens retaining frame F7 that retains the seventh lens group L7 is pressed against the first guide bar 27 in a direction substantially parallel to the straight line SL2, thereby preventing the central axis of the seventh lens group L7 from deviating from the optical axis OA.

[0061] Furthermore, in this embodiment, bearing 51 has a cylindrical outer shape, and in a plane perpendicular to optical axis OA, central axis AX4 of bearing 51 is substantially perpendicular to line SL2. This allows the direction in which bearing 51 is pressed against first guide bar 27 to be substantially parallel to line SL2, and seventh lens retaining frame F7 is pressed against first guide bar 27 in a direction substantially parallel to line SL2, thereby preventing the central axis of seventh lens group L7 from deviating from optical axis OA.

[0062] Furthermore, in this embodiment, the seventh lens retaining frame F7 has holes 315a and 315b that are spaced apart in the direction of the optical axis OA and through which the first guide bar 27 is inserted, and a bearing 51 is disposed between the holes 315a and 315b in the direction of the optical axis OA. This allows the holes 315a and 315b to be pressed against the first guide bar 27 in a well-balanced manner. Furthermore, the space within the first engaging portion 31 can be effectively utilized.

[0063] In this embodiment, lens barrel 100 includes ninth lens group L9, which is positioned closer to the image than seventh lens group L7, and which has a shape that is like a circle with the top and bottom cut out on a plane perpendicular to optical axis OA. This allows for a reduction in the weight of ninth lens group L9, and therefore the weight of lens barrel 100.

[0064] Furthermore, in this embodiment, when the seventh lens group L7 and the ninth lens group L9 are closest to each other, a portion of the seventh lens retaining frame F7 (a portion of the first engagement portion 31) is located closer to the image side than the surface of the ninth lens group L9 closest to the subject in the optical axis OA direction. In other words, when the seventh lens group L7 and the ninth lens group L9 are closest to each other, the ninth lens group L9 and a portion of the seventh lens retaining frame F7 overlap in the radial direction of a circle centered on the optical axis OA. This allows the distance between the first guide bar 27 and the optical axis OA to be shorter than when the planar shape of the ninth lens group L9 is circular. Because the first guide bar 27 is closer to the optical axis OA, the radial distance centered on the optical axis OA of the connecting portion connecting the cylindrical portion 30 of the seventh lens retaining frame F7 to the first engagement portion 31 can be shortened. This allows the weight of the seventh lens retaining frame F7 to be reduced, and ultimately the weight of the lens barrel 100 to be reduced. Furthermore, since the length of first guide bar 27 and the distance between holes 315a and 315b can be increased, the tilt of the central axis of seventh lens group L7 relative to optical axis OA can be suppressed.

[0065] In this embodiment, the lens barrel 100 includes an eighth lens holder frame F8 that holds the eighth lens group L8 and a second guide bar 28 that guides the eighth lens holder frame F8 in the optical axis OA direction. When the eighth lens group L8 and the ninth lens group L9 are closest to each other, a portion of the eighth lens holder frame F8 is positioned closer to the image side than the surface of the ninth lens group L9 closest to the subject in the optical axis OA direction. This allows the distance between the second guide bar 28 and the optical axis OA to be reduced compared to when the planar shape of the ninth lens group L9 is circular. Because the second guide bar 28 is closer to the optical axis OA, the radial distance of the connecting portion connecting the cylindrical portion 40 and the second engagement portion 41 of the eighth lens holder frame F8, centered on the optical axis OA, can be reduced. This allows the eighth lens holder frame F8 to be lightweight, and ultimately the lens barrel 100 to be lightweight. Furthermore, since the length of the second guide bar 28 and the distance between the holes 415a and 415b can be increased, the tilt of the central axis of the eighth lens group L8 relative to the optical axis OA can be suppressed.

[0066] In the above embodiment, bearing 51 may be a resin bearing, or may be one in which a resin such as polyacetal is press-fitted into the outer diameter. Also, instead of bearing 51, for example, a metal, plastic, or resin member other than bearing 51 may be brought into contact with first guide bar 27 and second guide bar 28. Furthermore, the outer shape of the member that comes into contact with first guide bar 27 and second guide bar 28 is not limited to a cylindrical shape, and may be, for example, a rectangular parallelepiped shape.

[0067] In the above embodiment, lens barrel 100 includes multiple focus lens groups, but the above embodiment can also be applied to cases where there is only one focus lens group. Also, in the above embodiment, lens barrel 100 is a zoom lens, but it may also be a single focal length lens.

[0068] Furthermore, the number and arrangement of lens groups included in lens barrel 100 are not limited to those in the above embodiment. Furthermore, the configuration for moving movable barrel 110 in the direction of optical axis OA is not limited to those in the above embodiment. For example, movable barrel 110 may be guided in the direction of optical axis OA by a guide bar rather than a linear groove. Furthermore, movable barrel 110 may be a fixed barrel that does not move in the direction of optical axis OA. Furthermore, while first drive source unit 70 and second drive source unit 80 have been described as having racks, they may also be configured to have nuts.

[0069] The above-described embodiment is a preferred example of implementation, but is not limited to this, and various modifications are possible within the scope of the gist, and any constituent elements may be combined. [Explanation of symbols]

[0070] 1 camera 27 First guide bar 28 Second guide bar 51 Bearing 52 Bearing support 53 Compression spring 100 Lens barrel 101 Camera Body 110 Mobile Cylinder 315a,315b hole 415a, 415b holes F7 7th lens holder F8 8th lens holder F9 9th lens holder L7 7th lens group L8 8th lens group L9 9th lens group

Claims

[Claim 1] a first lens holding frame that holds a first lens; a first guide shaft that guides the first lens holding frame in the optical axis direction; a contact member that comes into contact with the first guide shaft; a biasing member that contacts the first lens holding frame and biases the contact member toward the first guide shaft; A lens barrel comprising:

Images