Lens barrel and optical apparatus

Abstract

To provide a lens barrel with which deformation or breakage, etc. hardly occurs, and it is possible to maintain drive performance.SOLUTION: A lens barrel 100 comprises: a guide cylinder 60 that guides a first lens holding member 1 that holds a first lens group L1, so as to be capable of linearly proceeding in a direction of an optical axis; a cam ring 7 that is held to the guide cylinder 60 so as to enclose the guide cylinder 60 to be capable of rotating around the optical axis; and a fourth lens holding member 4 that is secured to the guide cylinder 60. The cam ring 7 has a first rugged surface part 7t that faces the fourth lens holding member 4, and the fourth lens holding member 4 has a second rugged surface part 4t that faces the first rugged surface part 7t. When the cam ring 7 moves the optical axis direction so as to approach the fourth lens holding member 4 by external force, the first and second rugged surface parts 7t, 4t are engaged, and the rotation of the cam ring 7 around the optical axis is thereby restricted.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a lens barrel and an optical device, and particularly to a configuration for movably supporting a lens group in a lens barrel.

Background Art

[0002] As a lens barrel (interchangeable lens) attached to a single-lens reflex camera or a lens barrel of a lens-integrated camera, when focusing on a subject, a part of the built-in lens group (focus lens) is linearly moved in the optical axis direction. For example, Patent Document 1 discloses a technique for suppressing the transmission of an external force to a drive mechanism that drives a focus lens when an external force such as an impact force is applied to the focus lens.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the technique disclosed in Patent Document 1 above, when a large external force is applied to the lens barrel, the rotation of the cam ring is stopped to prevent damage to gears or the like for rotating the cam ring. However, when stopping the rotation of the cam ring, most of the external force is received by the cam groove provided in the cam ring, so there is a risk of deformation or breakage in the cam groove and the cam follower that engages with the cam groove. And when damage or deformation occurs in the cam groove or cam follower, the driving performance when moving the lens in the optical axis direction deteriorates.

[0005] The present invention has been made in view of such circumstances, and an object thereof is to provide a lens barrel in which deformation, breakage, etc. due to an external force are unlikely to occur and the driving performance can be maintained. [Means for solving the problem]

[0006] The lens barrel according to the present invention comprises a lens, a holding member for holding the lens, a guide tube for guiding the holding member so that it can move in a straight line in the optical axis direction of the lens, a cam ring held so as to surround the guide tube so as to be rotatable with respect to the optical axis of the lens, and a fixing member fixed to the guide tube, wherein the cam ring has a first contact portion facing the fixing member in the optical axis direction, and the fixing member has a second contact portion facing the first contact portion in the optical axis direction, and when the cam ring is moved by an external force so as to approach the fixing member in the optical axis direction, the first contact portion and the second contact portion come into contact, thereby restricting the rotation of the cam ring about the optical axis. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a lens barrel that is less susceptible to deformation or damage due to external forces and can maintain its driving performance. [Brief explanation of the drawing]

[0008] [Figure 1] This is a cross-sectional view of the lens barrel in the retracted state according to the embodiment. [Figure 2] This is a cross-sectional view of the lens barrel in its extended state. [Figure 3] This is an exploded perspective view of the lens barrel. [Figure 4] This is a cross-sectional view of the motor unit located within the lens barrel. [Figure 5] This is a perspective view of the cam ring on the lens barrel. [Figure 6] This is a plan view of the inner surface of the cam ring. [Figure 7] This is a cross-sectional view showing the relationship between the cam follower and the cam groove of the cam ring. [Figure 8] This is a perspective view of the fourth lens retaining member of the lens barrel. [Figure 9]This is a side view of the portion where the fourth lens holding member and the cam ring face each other. [Figure 10] This is an enlarged view of region A in Figure 9(a). [Figure 11] This is a cross-sectional view of the lens barrel, including the photointerrupter and optical axis. [Figure 12] This is a perspective view of the guide tube attached to the lens barrel. [Figure 13] These are side and cross-sectional views showing the configuration of the photointerrupter. [Figure 14] This is a perspective view showing the state before and after the motor unit is incorporated into the guide tube. [Modes for carrying out the invention]

[0009] Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0010] Figure 1 is a first cross-sectional view of the lens barrel 100 according to the embodiment, showing the retracted state for infinity focus. Figure 2 is a second cross-sectional view of the lens barrel 100, showing the extended state for close-up focus.

[0011] The first cross-sectional view in Figure 1 shows a cross-section including the first cam follower 16 and the second cam follower 41a, described later, and the optical axis, in the extended state. The second cross-sectional view in Figure 2 shows a vertical cross-section (including the optical axis and in a plane parallel to the height direction of the imaging device body) with the lens barrel 100 mounted on the imaging device body.

[0012] The lens barrel 100 is specifically a detachable interchangeable lens that can be attached to the main body of an imaging device (not shown), such as a single-lens reflex camera. However, the lens barrel 100 may be integrally constructed with the main body of the imaging device. Furthermore, the use of the lens barrel 100 is not limited to cameras; it can also be applied to other optical instruments, such as telescopes (monoculars).

[0013] The lens barrel 100 includes a mount 8 for attaching to the imaging device body, and the mount 8 is fixed to the rear fixed cylinder 70b. A contact block 28 is fixed to the mount 8 to enable communication with the imaging device body and power supply from the imaging device body. A back cover 9 is also fixed to the mount 8. Note that claws are integrally formed on the back cover 9, and the back cover 9 is fixed to the mount 8 by utilizing the elastic force of the claws.

[0014] The rear fixed cylinder 70b and the front fixed cylinder 70a are coupled in the optical axis direction to form the fixed cylinder 70. A focus ring 12 for performing focusing by manual operation is provided on the fixed cylinder 70 so as to be rotatable by manual operation about the optical axis. A hood mount 13 that enables attachment and detachment of a hood (not shown) that blocks the incidence of harmful light is provided at the front end of the front fixed cylinder 70a.

[0015] An outer ring 10 is fixed to the rear fixed cylinder 70b, and a substrate 15 is fixed to the outer ring 10. Electronic components are mounted on the substrate 15. The substrate 15 is also connected to the contact block 28 via a flexible printed circuit board. The diaphragm device 30, motor unit 14, encoder flexible printed circuit board (FPC53 (see FIG. 13(b))), AF / MF changeover switch, and photointerrupter 18, etc., described later are electrically connected to the substrate 15 via a flexible printed circuit board (not shown). A microcomputer for performing various drive controls of the diaphragm device 30 and motor unit 14 is mounted on the substrate 15.

[0016] The lens barrel 100 has a first lens group L1, a second lens group L2, a third lens group L3, and a fourth lens group L4. The first lens group L1 is held by the first lens holding member 1, the second lens group L2 is held by the second lens holding member 2, the third lens group L3 is held by the third lens holding member 3, and the fourth lens group L4 is held by the fourth lens holding member 4, respectively.

[0017] An aperture device 30 is positioned between the first lens holding member 1 and the second lens base plate 21 in the optical axis direction. The aperture device 30 is equipped with a motor (not shown) as a drive source, and the amount of light passing through the lens barrel 100 can be adjusted by controlling the drive of the motor to change the opening area of ​​the aperture blades built into the aperture device 30.

[0018] The first lens group L1, the second lens group L2, the third lens group L3, the fourth lens group L4, and the aperture device 30 constitute the photographic optical system of the lens barrel 100. In the lens barrel 100, the first lens group L1 to the third lens group L3 (excluding the fourth lens group L4) and the aperture device 30 form the main components of a movable lens group that can move integrally along the optical axis. Thus, the lens barrel 100 is configured as a fixed-focus lens in which the movable lens group moves along the optical axis when focusing on a subject.

[0019] The first lens holding member 1 is fixed to the second lens base plate 21 at three points by screws (not shown). A first cam follower 16, which has a frustoconical shape, is press-fitted and fixed to the outer surface of the first lens holding member 1 at three points at approximately equal intervals in the circumferential direction, so as to protrude outward. The second lens holding member 2 is held on the second lens base plate 21 so as to be movable in a direction perpendicular to the optical axis and so as to be tiltable with respect to the optical axis.

[0020] The fourth lens holding member 4 has an outer peripheral flange portion 4f provided on the outer circumference side of the guide tube 60 so as to face the cam ring 7 described later. The fourth lens holding member 4 is a fixing member that is connected to the guide tube 60 by the outer peripheral flange portion 4f being fixed by the guide tube 60.

[0021] The first lens holding member 1 is engaged with the guide tube 60. Specifically, each holding portion provided on the first lens holding member 1 to hold the first cam follower 16 has key portions 1b formed on both sides in the circumferential direction. The key portions 1b are engaged with three straight grooves 60a (see Figure 12) formed in the guide tube 60, thereby allowing the first lens holding member 1 to move in a straight line in the optical axis direction.

[0022] The cam ring 7 is positioned to rotatably surround the outer surface of the guide tube 60 and at a fixed position in the direction of the optical axis. Play in the direction of the optical axis of the cam ring 7 is suppressed by the biasing force of the wave washer 19 (biasing member) positioned on the front side of the cam ring 7, which presses the cam ring 7 toward the rear side (mount 8 side) in the direction of the optical axis relative to the guide tube 60.

[0023] A motor unit 14 is fixed to the guide tube 60. Figure 4 is a cross-sectional view of the motor unit 14 in a plane perpendicular to the optical axis. The motor unit 14 comprises a motor (not shown) and a drive base plate 50, which is a sheet metal member on which the motor is mounted. In the motor unit 14, the motor's output gear 14g is enclosed and held within the drive base plate 50 and meshes with a cam ring gear 7p provided on the outer circumference of the cam ring 7. As the cam ring 7 rotates in accordance with the rotation of the output gear 14g driven by the motor, the first cam follower 16 moves in the optical axis direction due to the cam lift of the first cam groove 7a (see Figures 5 to 7) provided in the cam ring 7, which will be described later. At that time, the first lens holding member 1 moves linearly in the optical axis direction, guided by the straight groove 60a. That is, the movable lens group moves in the optical axis direction. By moving the movable lens group in the optical axis direction according to the subject distance, focusing is performed between the infinity shooting position and the close shooting position.

[0024] On the subject-facing side of the first lens group L1, a filter frame 40, which is a cylindrical member to which a filter (not shown), an example of an optical component, can be attached, is positioned. The filter frame 40 is fixed to the connecting cylinder 41 by screws. On the front of the filter frame 40, a decorative ring 11 is positioned to conceal the screws used to fix the filter frame 40 to the connecting cylinder 41 and to enhance the aesthetic appearance.

[0025] Between the connecting cylinder 41 and the first lens holding member 1, a biasing spring 25 is positioned to bias the first lens holding member 1 (movable lens group) and the connecting cylinder 41 in a direction that separates them. The biasing spring 25 has an annular shape that surrounds the first lens group L1 and is held by the first lens holding member 1 at a position on the back side of the subject-side vertex of the first lens group L1.

[0026] A second cam follower 41a is formed integrally with the main body of the connecting cylinder 41 at three locations in the circumferential direction, at a different phase from the first cam follower 16. A third cam follower 41b is also formed integrally with the main body of the connecting cylinder 41 at three locations in the circumferential direction, at a different phase from the first cam follower 16 and the second cam follower 41a. Both the second cam follower 41a and the third cam follower 41b have a frustoconical shape, similar to the first cam follower 16. Note that, as the first cam follower 16 is press-fitted into the first lens holding member 1, the second cam follower 41a and the third cam follower 41b may be fixed to the main body of the connecting cylinder 41 as separate parts.

[0027] Figure 5 is a perspective view of the cam ring 7 as seen from the rear side. Figure 6 is a plan view of the inner surface of the cam ring 7. Three circumferential grooves 7d are provided on the subject side of the inner surface of the cam ring 7 at the same position in the optical axis direction, and the three circumferential grooves 7d engage one-to-one with three projections 60b provided on the outer circumference of the guide tube 60. As a result, the cam ring 7 can rotate relative to the guide tube 60 while its position in the optical axis direction is restricted.

[0028] The inner surface of the cam ring 7 has three first cam grooves 7a, three second cam grooves 7b, and three third cam grooves 7c with different groove widths from the second cam grooves 7b, and the surface of each cam groove (side surface of the cam groove) is tapered (slope-shaped) (see Figure 7). The first cam groove 7a, second cam groove 7b, and third cam groove 7c each have an infinity focus end on the back side that focuses on subjects at infinity, and a close focus end on the subject side that focuses on nearby subjects. The area between the infinity focus end and the close focus end is the focusable region (shooting region), and the infinity focus end and close focus end of each cam groove are indicated by circles in Figure 6.

[0029] A first cam groove introduction portion 7g is formed such that it extends in the optical axis direction from the end of the first cam groove 7a on the infinity focus side toward the subject side (forward) of the cam ring 7, and is open at the subject-side end face of the cam ring 7. The first cam groove introduction portion 7g is a groove for engaging the first cam follower 16 with the first cam groove 7a, that is, for assembling the movable lens group including the first lens holding member 1 into the cam ring 7.

[0030] A second cam groove introduction portion 7h is provided, extending in the optical axis direction from the near-focus end of the second cam groove 7b toward the subject side of the cam ring 7, and opening at the subject-side end face of the cam ring 7. The first cam groove introduction portion 7g and the second cam groove introduction portion 7h share a first confluence portion 7e on the subject side of the cam ring 7. A third cam groove introduction portion 7j is provided, extending in the optical axis direction from the near-focus end of the third cam groove 7c toward the subject side of the cam ring 7, and opening at the subject-side end face of the cam ring 7. The second cam groove introduction portion 7h and the third cam groove introduction portion 7j are grooves for assembling the connecting cylinder 41 into the cam ring 7 by engaging the second cam follower 41a and the third cam follower 41b with the second cam groove 7b and the third cam groove 7c, respectively.

[0031] A circumferential groove introduction section 7k is provided in the circumferential groove 7d, extending in the optical axis direction toward the subject side of the cam ring 7 and opening at the subject-side end face of the cam ring 7. The third cam groove introduction section 7j and the circumferential groove introduction section 7k share a second confluence section 7f on the subject side of the cam ring 7.

[0032] This configuration makes it possible to reduce the number of introduction grooves. Furthermore, by positioning the circumferential groove 7d without intersecting the first confluence section 7e or the second confluence section 7f, it becomes unnecessary to increase the diameter of the cam ring 7 to avoid intersections between the circumferential groove 7d and the first and second confluence sections 7e and 7f. In addition, since the projection 60b does not cross each cam groove introduction section when the cam ring 7 rotates around the outer circumference of the guide cylinder 60, the projection 60b can move smoothly within the circumferential groove 7d when the cam ring 7 rotates, enabling smooth focusing.

[0033] Figure 7 is a cross-sectional view showing the relationship between the cam groove provided in the cam ring 7 and the cam follower that engages with the cam groove. As shown in Figures 7(a) to (c), the first cam follower 16 engages with the first cam groove 7a, the second cam follower 41a engages with the second cam groove 7b, and the third cam follower 41b engages with the third cam groove 7c.

[0034] The first cam groove 7a, the second cam groove 7b, and the third cam groove 7c have the same cam lift amount. The filter frame 40 is not held by the moving lens group, but is fixed to the connecting tube 41, so it always moves in the same way as the moving lens group with the same lift amount, facing forward on the subject side of the moving lens group.

[0035] The movable lens group, including the first lens holding member 1, and the connecting barrel 41 are biased in a direction away from each other by a biasing spring 25. Therefore, in the normal state, the first cam follower 16 provided on the first lens holding member 1 is biased toward the wall surface of the first cam groove 7a on the mount 8 side (upper side in Figures 7(a) to (c)). On the other hand, the second cam follower 41a is biased toward the wall surface of the second cam groove 7b on the subject side (lower side in Figures 7(a) to (c)). As a result, when taking images with an imaging device to which the lens barrel 100 is attached, it is possible to take images without impairing the optical characteristics even if the posture of the imaging device changes.

[0036] A gap t1 is formed between the second cam follower 41a and the wall surface of the second cam groove 7b on the mount 8 side. In the normal state, the third cam follower 41b does not come into contact with the cam surface of the third cam groove 7c, and a gap t2 is formed between the third cam follower 41b and the wall surface of the third cam groove 7c on the mount 8 side. Here, the relationship t1≧t2 holds between gaps t1 and t2.

[0037] When an external force such as an impact is applied to the filter frame 40 from the subject side, the external force is first transmitted to the engagement portion between the second cam follower 41a and the second cam groove 7b, which are located on the connecting cylinder 41 that holds the filter frame 40 positioned on the subject side (front side). Subsequently, the external force is transmitted to the engagement portion between the third cam follower 41b and the third cam groove 7c. At this time, as described above, a gap t1 is formed between the second cam follower 41a and the wall surface of the second cam groove 7b on the mount 8 side, and a gap t2 is also formed between the third cam follower 41b and the wall surface of the third cam groove 7c on the mount 8 side. Therefore, the biasing spring 25 is easily compressed, and the biasing spring 25 can mitigate the impact, making it possible to prevent the second cam follower 41a from falling out of the second cam groove 7b and the third cam follower 41b from falling out of the third cam groove 7c.

[0038] Furthermore, the focusing regions of the first cam groove 7a and the second cam groove 7b are arranged so as not to overlap in the optical axis direction (in Figure 6, there is a certain distance between the infinity focusing end of the second cam groove 7b and the near focusing end of the first cam groove 7a in the circumferential direction). This suppresses the transmission of external forces to the first cam groove 7a. Moreover, the connecting cylinder 41 and the movable lens group are engaged independently of the cam ring 7. Therefore, external forces are not transmitted to the engagement portion between the first cam follower 16 and the first cam groove 7a, preventing deformation or damage to the first cam follower 16 and the first cam groove 7a, thereby preventing a decrease in optical performance.

[0039] Figure 8 is a perspective view of the fourth lens retaining member 4. On the cam ring 7, on the opposing portions of the outer peripheral flange portion 4f, multiple cam ring-side protrusions 7t (first contact portion (hereinafter referred to as "first protrusion 7t")) are formed in an arc shape when viewed from the direction of the optical axis, centered on the optical axis, at multiple locations as shown in Figures 2 and 5. Furthermore, on the outer peripheral flange portion 4f provided on the fourth lens retaining member 4, the portion facing the first protrusion 7t is formed a fourth lens retaining member-side protrusion 4t (second contact portion (hereinafter referred to as "second protrusion 4t")).

[0040] Figure 9 is a side view (viewed from a direction perpendicular to the optical axis) showing various positional relationships between the first uneven portion 7t and the second uneven portion 4t. Figure 10 is an enlarged view of region A shown in Figure 9(a). Viewed from a direction perpendicular to the optical axis, the first uneven portion 7t has equally spaced vertices 7v and bases 7w, and is formed so that triangles with a slope 7s between the vertices 7v and bases 7w are continuous in the circumferential direction. Similarly, the second uneven portion 4t has equally spaced vertices 4v and bases 4w, and is formed so that triangular shapes with a slope 4s between the vertices 4v and bases 4w are continuous in the circumferential direction. The first uneven portion 7t and the second uneven portion 4t have equivalent uneven shapes where the vertices of one contact point and the bases of the other contact point contact each other. In other words, if the first uneven surface 7t and the second uneven surface 4t are moved in parallel along the optical axis direction from the state shown in Figure 9(a) and brought into contact, then the inclined plane 7s and the inclined plane 4s will come into contact (the vertex 4v and the base 7w will come into contact, and the base 4w and the vertex 7v will come into contact). Here, we define the angle that inclined planes 4s and 7s make with respect to the optical axis direction as the inclination angle, and assume that the inclination angle of inclined plane 4s and the inclination angle of inclined plane 7s are both angles θ.

[0041] During normal operation of the lens barrel 100, the first uneven portion 7t and the second uneven portion 4t maintain a constant gap D as shown in Figure 10, and the cam ring 7 is rotatable about the optical axis relative to the fourth lens holding member 4.

[0042] When an external force such as an impact that cannot be absorbed by the biasing spring 25 is applied to the filter frame 40 from the subject side, the first cam follower 16 attached to the first lens holding member 1 moves toward the back side in the optical axis direction along the lift of the first cam groove 7a. At that time, a rotational force is generated in the cam ring 7, and the generated rotational force is transmitted to the output gear 14g.

[0043] If the force transmitted to the output gear 14g causes deformation or damage to the motor unit 14 or the output gear 14g, the accuracy of transmitting the rotational driving force generated by the motor to the cam ring 7 will decrease, resulting in malfunction of the moving lens group.

[0044] To address this problem, in the lens barrel 100, when the filter frame 40 is struck from the subject side, the cam ring 7 moves in the direction of approaching the fourth lens holding member 4 (towards the back side) along the optical axis. Here, since the gap D is maintained with the wave washer 19 biasing the cam ring 7 towards the back side, the gap D does not easily become smaller.

[0045] When a greater external force is applied to the filter frame 40 from the subject side, as shown in Figure 9(b), the cam ring 7 and the fourth lens holding member 4 approach each other in the optical axis direction, causing the apex 7v and bottom 4w to engage, and the apex 4v and bottom 7w to engage. These engagements are possible regardless of the rotational position of the cam ring 7 because the apex 7v and bottom 7w, and the apex 4v and bottom 4w, are formed radially around the optical axis. Furthermore, the cam ring 7 and the guide tube 60 are made of an elastic material, so when the filter frame 40 is subjected to an external force such as an impact from the subject side, temporary deformation is likely to occur in the cam ring 7 and the guide tube 60, making it easier for the second uneven portion 4t and the first uneven portion 7t to engage. Examples of elastic materials that make up the cam ring 7 and the guide tube 60 include polycarbonate, polyamide, polyacetal, and ABS resin.

[0046] The cam ring 7, having the first protrusion 7t, is rotatably held in the guide tube 60, and the fourth lens holding member 4, having the second protrusion 4t, is fixed to the guide tube 60. Therefore, the gap D into which the first protrusion 7t and the second protrusion 4t can engage is not affected by other parts, and the gap D can be maintained with high precision.

[0047] When the first uneven portion 7t and the second uneven portion 4t engage due to an external force such as an external impact, a rotational force is generated in the cam ring 7, causing the inclined surfaces 7s and 4s to come into contact and slide, pushing the cam ring 7 back in a direction away from the fourth lens holding member 4. In this way, as shown in Figures 9(c) and (d), the first uneven portion 7t overcomes the second uneven portion 4t.

[0048] In this case, the closer the angle θ is to 0 degrees, the less likely it is that the rotational force of the cam ring 7 will be transmitted to the output gear 14g. However, as the angle θ approaches 0 degrees, the impact force from the first cam follower 16 to the cam ring 7 is transmitted to the first cam groove 7a without being dissipated as a force that rotates the cam ring 7, making the first cam groove 7a more susceptible to deformation and damage such as dents. On the other hand, if the angle θ is made too large, the motor unit 14 and the output gear 14g are more susceptible to damage. Taking these factors into consideration, it is desirable to set the angle θ to be between 30° and 60°.

[0049] As described above, by configuring the lens barrel 100 in the manner described, it is possible to prevent damage to the cam ring 7, motor unit 14, and first cam follower 16, while suppressing a decline in the optical performance, operation, and function of the lens barrel 100.

[0050] Next, the configuration for detecting the position of the moving lens group will be described. Figure 11 is a cross-sectional view of the lens barrel 100 including the photointerrupter 18 and the optical axis. Figure 12 is a perspective view of the guide barrel 60.

[0051] The guide tube 60 has a retaining groove 60h formed therein, which is open on the back side in the optical axis direction and on the outer circumference in the radial direction (direction perpendicular to the optical axis). A photointerrupter 18 (photosensor) is arranged (housed) in the retaining groove 60h as a detection unit for detecting the position of the moving lens group. The second lens base plate 21 is provided with ribs 21a, and the position of the moving lens group can be detected using the square wave signal output from the photointerrupter 18 when the ribs 21a pass between the light-emitting and light-receiving parts of the photointerrupter 18.

[0052] Figure 13 shows the state in which the photointerrupter 18 is positioned. More specifically, Figure 13(a) is a side view showing the photointerrupter 18 and its surroundings, and Figure 13(b) is a cross-sectional view showing the photointerrupter 18 and its surroundings (an enlarged view of the photointerrupter 18 and its vicinity in Figure 12).

[0053] As shown in Figure 8, an elastic portion 4d is provided in the portion of the fourth lens holding member 4 where the outer peripheral flange portion 4f is not formed. When the fourth lens holding member 4 is fixed to the guide tube 60, the elastic portion 4d biases the photo interrupter 18 toward the subject in the direction of the optical axis with respect to the wall surface 60j provided on the guide tube 60 so as to be approximately perpendicular to the optical axis.

[0054] The optical axis position of the photointerrupter 18 is restricted by two fixed elements: the guide tube 60 and the fourth lens holding member 4, which holds the fourth lens group L4 adjacent to the moving lens group. This enables highly accurate position detection of the moving lens group. Furthermore, since the elastic part 4d is positioned so as not to overlap with the fourth lens group L4 in the optical axis direction (not to overlap when viewed from a direction perpendicular to the optical axis), the impact of deformation of the elastic part 4d on optical performance is small.

[0055] Furthermore, an elastic portion 50d is formed on the inner circumference side of the drive base plate 50 of the motor unit 14, which biases the photointerrupter 18, held in the holding groove 60h of the guide tube 60, against the side wall surface 60k, which is the bottom surface of the holding groove 60h of the guide tube 60. Since the cam ring gear 7p is formed on the outer circumference side of the cam ring 7, it is possible to assemble the lens barrel 100 while biasing the photointerrupter 18 against the side wall surface 60k. Variations in the size of the photointerrupter 18 and variations in mounting on the FPC 53 are absorbed by the biasing by the elastic portion 50d, thereby enabling high-precision positioning of the photointerrupter 18. Moreover, by positioning the photointerrupter 18 on the guide tube 60, which holds the movable lens group so that it can move in the optical axis direction, it is possible to reduce the gap between the guide tube 60 and the rib 21a of the second lens base plate 21, and it becomes possible to use a smaller photointerrupter 18.

[0056] Thus, in the lens barrel 100, the photointerrupter 18 is automatically fixed by integrating other parts necessary to achieve a predetermined function adjacent to it, without using dedicated parts as in known technologies (for example, Japanese Patent Publication No. 2019-132938). Therefore, it is possible to reduce costs by reducing the number of parts, avoid increasing size (increasing diameter), and provide a lens barrel 100 with excellent assembly workability.

[0057] Figure 14(a) is a perspective view showing the state before the motor unit 14 is incorporated into the guide tube 60, and Figure 14(b) is a perspective view showing the state after the motor unit 14 is incorporated into the guide tube 60. When the drive base plate 50 is placed on the outer circumference side of the fourth lens holding member 4 where the outer circumference flange portion 4f is not formed (the notched portion of the outer circumference flange portion 4f) and held by the guide tube 60, the cam ring gear 7p and the output gear 14g mesh simultaneously. This makes it possible to position the motor unit 14 closer to the optical axis, enabling miniaturization (reduction in diameter) of the lens barrel 100.

[0058] Although the present invention has been described in detail above based on its preferred embodiments, the present invention is not limited to these specific embodiments, and various forms that do not depart from the spirit of the invention are also included in the present invention. Furthermore, each of the embodiments described above is merely one embodiment of the present invention, and it is possible to combine each embodiment as appropriate.

[0059] For example, in the above embodiment, the movable lens group is composed of a plurality of lens groups and a plurality of holding members that hold them together, but at least one lens and at least one holding member that holds it together may be configured to be movable in the optical axis direction.

[0060] This embodiment includes the following configurations and methods. (Configuration 1) A lens barrel comprising: a lens; a holding member for holding the lens; a guide tube for guiding the holding member so that it can move in a straight line in the optical axis direction of the lens; a cam ring held so as to surround the guide tube so as to be rotatable with respect to the optical axis of the lens; and a fixing member fixed to the guide tube, wherein the cam ring has a first contact portion facing the fixing member in the optical axis direction, and the fixing member has a second contact portion facing the first contact portion in the optical axis direction, and when the cam ring is moved by an external force so as to approach the fixing member in the optical axis direction, the first contact portion and the second contact portion come into contact, thereby restricting the rotation of the cam ring about the optical axis. (Configuration 2) The lens barrel according to Configuration 1, characterized in that the first contact portion and the second contact portion are each formed in an arc shape with respect to the optical axis, with respect to the optical axis. (Configuration 3) The lens barrel according to Configuration 1 or 2, characterized in that the first contact portion and the second contact portion each have equivalent irregularities such that the apex of one contact portion and the bottom of the other contact portion come into contact with each other. (Configuration 4) The lens barrel according to Configuration 3, characterized in that the irregularities are formed such that, when viewed from a direction perpendicular to the optical axis, the vertices and bases are formed at equal intervals, and a slanted surface is formed between the vertices and bases, and these triangular shapes are continuous in the circumferential direction. (Configuration 5) The lens barrel according to Configuration 4, characterized in that the angle the inclined surface makes with the optical axis is 30° or more and 60° or less. (Configuration 6) A lens barrel according to any one of Configurations 1 to 5, characterized in that a circumferential groove provided in the circumferential direction at the same position in the optical axis direction on the inner circumferential surface of the cam ring engages with a projection provided on the outer circumferential surface of the guide cylinder, thereby holding the cam ring rotatably in a fixed position in the optical axis direction relative to the guide cylinder. (Configuration 7) The retaining member has a first cam follower that protrudes toward the outer circumference of the lens barrel, The cam ring has a first cam groove that engages with the first cam follower, The lens barrel according to configuration 6, characterized in that the first cam follower is guided into the first cam groove in accordance with the rotation of the cam ring, and the retaining member moves in the direction of the optical axis. (Configuration 8) A lens barrel according to Configuration 7, comprising: a cylindrical member for holding a predetermined optical component; a connecting cylinder to which the cylindrical member is fixed; and a biasing member for biasing the cam ring toward the rear side of the lens barrel, wherein the connecting cylinder has a second cam follower and a third cam follower protruding toward the outer circumference; the cam ring has a second cam groove that engages with the second cam follower and a third cam groove that engages with the third cam follower; and the biasing force of the biasing member forms a first gap between the second cam follower and the rear side wall surface of the lens barrel in the second cam groove, and a second gap between the third cam follower and the rear side wall surface of the lens barrel in the third cam groove. (Configuration 9) The lens barrel according to Configuration 8, characterized in that the first gap is larger than the second gap. (Configuration 10) The lens barrel according to Configuration 8 or 9, wherein the cam ring has a first confluence portion where a first cam groove introduction portion for engaging the first cam follower with the first cam groove and a second cam groove introduction portion for engaging the second cam follower with the second cam groove meet, a second confluence portion where a third cam groove introduction portion for engaging the third cam follower with the third cam groove and a circumferential groove introduction portion for engaging the projection with the circumferential groove meet, and the first confluence portion and the second confluence portion do not intersect with the circumferential groove. (Composition 11) The lens barrel according to any one of configurations 1 to 10, characterized in that the fixing member holds the lens. (Configuration 12) A lens barrel according to any one of Configurations 1 to 11, characterized in that the fixing member is located on the back side of the cam ring in the optical axis direction. (Configuration 13) An optical instrument characterized by comprising a lens barrel as described in any one of Configurations 1 to 12. [Explanation of symbols]

[0061] 1. First lens holding member 4. Fourth lens holding member 4t Second uneven section 7 Cam ring 7d circumferential groove 7t First uneven section 16 First Cam Follower 100 Lens barrel 40 filter frames 41 Connecting tube 41a Second Cam Follower 41b The third cam follower 60 Guide tube 60b Protrusion L1 First lens group L4, the fourth lens group

Claims

1. a lens; a holding member for holding the lens; a guide tube for guiding the holding member to move straight in the optical axis direction of the lens; a cam ring held so as to surround the guide tube rotatably about the optical axis of the lens with respect to the guide tube; a fixing member fixed to the guide tube, and the cam ring has a first abutting portion facing the fixing member in the optical axis direction, the fixing member has a second abutting portion facing the first abutting portion in the optical axis direction, and when the cam ring is moved by an external force so as to approach the fixing member in the optical axis direction, rotation of the cam ring about the optical axis is restricted by abutment between the first abutting portion and the second abutting portion. A lens barrel characterized by that.

2. The lens barrel according to claim 1, wherein each of the first abutting portion and the second abutting portion is formed by being divided into a plurality of arc-shaped portions centered on the optical axis when viewed from the optical axis direction.

3. The lens barrel according to claim 1 or 2, wherein each of the first abutting portion and the second abutting portion has equivalent unevenness in which the apex of one abutting portion abuts against the bottom of the other abutting portion.

4. The lens barrel according to claim 3, wherein the unevenness is formed such that, when viewed from a direction orthogonal to the optical axis, the apex and the bottom are formed at equal intervals, and a triangular shape in which a slope is formed between the apex and the bottom is continuous in the circumferential direction.

5. The lens barrel according to claim 4, wherein an angle formed by the slope and the optical axis is 30° or more and 60° or less.

6. The lens barrel according to claim 1 or 2, wherein a circumferential groove provided circumferentially at the same position in the optical axis direction on the inner peripheral surface of the cam ring engages with a protrusion provided on the outer peripheral surface of the guide tube, whereby the cam ring is rotatably held at a fixed position in the optical axis direction with respect to the guide tube.

7. The holding member has a first cam follower protruding toward the outer peripheral side of the lens barrel, and the cam ring has a first cam groove engaging with the first cam follower, and The lens barrel according to claim 6, wherein the first cam follower is guided by the first cam groove as the cam ring rotates, and the holding member moves in the optical axis direction.

8. a cylindrical member for holding a predetermined optical component; a connecting tube to which the cylindrical member is fixed, an urging member that urges the cam ring toward the back side of the lens barrel; the connecting cylinder has a second cam follower and a third cam follower that project to the outer peripheral side; the cam ring has a second cam groove that engages with the second cam follower and a third cam groove that engages with the third cam follower; a first gap is formed between the second cam follower and the wall surface on the back side of the lens barrel in the second cam groove, and a second gap is formed between the third cam follower and the wall surface on the back side of the lens barrel in the third cam groove due to the urging force of the urging member. The lens barrel according to claim 7, characterized in that.

9. The lens barrel according to claim 8, characterized in that the first gap is larger than the second gap.

10. the cam ring is a first merging portion where a first cam groove introduction portion for engaging the first cam follower with the first cam groove and a second cam groove introduction portion for engaging the second cam follower with the second cam groove merge; a second merging portion where a third cam groove introduction portion for engaging the third cam follower with the third cam groove and a circumferential groove introduction portion for engaging the protrusion with the circumferential groove merge; and having The lens barrel according to claim 8, characterized in that the first merging portion and the second merging portion do not intersect the circumferential groove.

11. The lens barrel according to claim 1 or 2, characterized in that the fixing member holds a lens.

12. The lens barrel according to claim 1 or 2, characterized in that the fixing member is disposed on the back side of the cam ring in the optical axis direction.

13. An optical apparatus comprising the lens barrel according to claim 1.

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