Optical devices and imaging devices

Abstract

To provide an optical device capable of suppressing the increase in zoom torque. [Solution] A zoom lens 1 comprising a 2-group lens barrel 112, a 3-group lens barrel 113, a 4-group lens barrel 114, a cover member 123, a cam ring 105 having multiple cam grooves and rotatable around the optical axis, a guide tube 102 having multiple straight grooves and restricting the movement of the cam ring 105 in the optical axis direction, and multiple cam followers engaging with each of the multiple cam grooves, wherein when the cam ring 105 is rotated from the wide end to the telephoto end, with respect to the wide end, the maximum relative movement between the 2-group lens barrel 112 and the 3-group lens barrel 113 is A, the maximum relative movement between the 3-group lens barrel 113 and the 4-group lens barrel 114 is B, and the maximum relative movement between the 2-group lens barrel 112 and the 4-group lens barrel 114 is C, A

Description

Technical Field

[0001] The present invention relates to an optical device and an imaging device including the same.

Background Art

[0002] There is known a configuration in which a lens holding frame that holds a lens is suspended by a cam follower engaged with a cam groove provided in a cam ring, enabling the lens holding frame to move forward and backward in the optical axis direction in accordance with the rotation of the cam ring.

[0003] If there is play between the cam groove and the cam follower, the lens holding frame may tilt depending on the posture of the photographer during focusing or zooming operations, changing the optical performance. Therefore, various mechanisms for eliminating the play between the cam groove and the cam follower have been disclosed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the mechanism disclosed in Patent Document 1, since each group is biased between a plurality of lens frames, rotational torque (hereinafter defined as self-rotating torque) is generated by the biasing force, causing the cam ring to rotate. Therefore, in order to stop the rotation of the cam ring, it is necessary to increase the holding force to stop the rotation, which may increase the zoom torque.

[0006] An object of the present invention is to provide an optical device capable of suppressing an increase in zoom torque.

Means for Solving the Problems

[0007] To achieve the above object, an optical device of the present invention includes a plurality of lens barrels including a first lens barrel, a second lens barrel, and a third lens barrel, a cover member, a cam ring provided with a plurality of cam grooves and rotatable about an optical axis, and a guide cylinder having a plurality of straight grooves for guiding the plurality of lens barrels and the cover member in the optical axis direction and restricting movement of the cam ring in the optical axis direction, and a plurality of cam followers engaging with the plurality of cam grooves respectively. When the cam ring rotates, the plurality of lens barrels and the cover member can move in the optical axis direction through the cam followers. When the cam ring is rotated from a wide end to a tele end, with the wide end as a reference, if the maximum value of the relative movement amount between the first lens barrel and the second lens barrel is A, the maximum value of the relative movement amount between the second lens barrel and the third lens barrel is B, and the maximum value of the relative movement amount between the first lens barrel and the third lens barrel is C, then A < B and A < C. The first lens barrel and the second lens barrel are biased against each other, and the third lens barrel and the cover member are biased against each other.

Effect of the Invention

[0008] According to the present invention, it is possible to provide an optical device capable of suppressing an increase in zoom torque.

Brief Description of the Drawings

[0009] [Figure 1] It is a cross-sectional view in a wide state of a zoom lens 1 which is an embodiment of the present invention. [Figure 2] It is a cross-sectional view in a tele state of a zoom lens 1 which is an embodiment of the present invention. [Figure 3] (A) and (B) are side views in a state where a zoom group is incorporated into a cam ring 105 and a guide cylinder 102. [Figure 4] (A) and (B) are side views in a state where a zoom group is incorporated into a guide cylinder 102. [Figure 5] It is a front view of only the zoom group. [Figure 6]This is a side view of the zoom group only. [Figure 7] This is a rear view of the zoom group only. [Figure 8] This is a graph of the group movement for each zoom group. [Figure 9] This is a graph of the relative movement of the zoom group. [Figure 10] This is a graph of the intersection angles of each group in the zoom group. [Figure 11] This is a graph of the angular difference between the zoom group. [Figure 12] This is a schematic diagram showing an example of the configuration of an imaging device. [Modes for carrying out the invention]

[0010] Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The XX axis in the drawings represents the optical axis. Figure 1 is a cross-sectional view along the optical axis of the zoom lens 1 (optical device) in the wide-angle state, which is an embodiment of the present invention. Figure 2 is a cross-sectional view of the zoom lens 1 in the telephoto state, which is an embodiment of the present invention. The wide-angle end represents the widest zoom state of the zoom lens 1, and the telephoto end represents the most telephoto zoom state.

[0011] In Figure 1, the mount 101 is a component fixed to the camera body 200a shown in Figure 12. The guide tube 102 is integrally fixed to the mount 101 together with the fixing tube 103 via the rear group base 104.

[0012] A cam ring 105 is held on the outer circumference of the guide tube 102 so as to be rotatable around the optical axis. The cam ring 105 is connected to a zoom ring 106, which is rotatably held on the outer circumference of the fixed tube 103, by a zoom key (not shown), and rotates integrally with the zoom ring 106 by operating the zoom ring 106 from the outside.

[0013] A zoom sensor (not shown) is attached to the fixed cylinder 103. The zoom sensor is a sensor that can electrically detect the rotation angle of the zoom ring 106, and is electrically connected to a control board 107 disposed near the mount 101, transmitting focal length information during zooming to the control circuit.

[0014] A contact block 108 is electrically connected to the control board 107, and functions to receive communication and power supply from the camera body 200a shown in FIG. 12.

[0015] The first lens group L1 is held by the first lens barrel 111, and the first lens barrel 111 is fixed to the guide cylinder 102. The second lens group L2 (first lens group) is held by the second lens barrel 112. The third lens group L3 (second lens group) is held by the third lens barrel 113. The fourth lens group L4 (third lens group) is held by the fourth lens barrel 114. The fifth lens group L5 is held by the fifth lens barrel 115. The fifth lens barrel 115 is fixed to the rear group base 104. An electromagnetic diaphragm unit 122 is held by the fifth lens barrel 115, and the electromagnetic diaphragm unit 122 is electrically connected to the control board 107.

[0016] The sixth lens group L6 is held by the sixth lens barrel 116. The sixth lens barrel 116 is held by the shift unit 117 so as to be movable in a plane orthogonal to the optical axis. The shift unit 117 includes an actuator for driving the sixth lens barrel 116, a sensor for detecting the driving amount, etc., and is fixed to the rear group base 104. The shift unit 117 is electrically connected to the control board 107. The control board 107 drives and controls the sixth lens barrel 116 to correct shake based on a shake signal detected by an acceleration sensor (not shown) attached to the fixed cylinder 103. The seventh lens group L7 is held by the rear group base 104.

[0017] The 8-group lens L8 is held by the 8-group lens barrel 118 and is held so as to be movable in the optical axis direction by a guide bar (not shown). The 7-group lens L7 is a lens for focus adjustment and is driven in the optical axis direction by a linear vibration wave motor (not shown) held by the rear group base 104. The linear vibration wave motor vibrates a piezoelectric element at a frequency in the ultrasonic region and drives it in the optical axis direction, and is based on a well-known technique. The linear vibration wave motor is electrically connected to the control board 107 by a flexible board (not shown).

[0018] The 9-group lens L9 is held by the 9-group lens barrel 119. The 9-group lens barrel 119 is fixed to the rear group base 104.

[0019] The 10-group lens L10 is held by the 10-group lens barrel 120 and is held so as to be movable in the optical axis direction by a guide bar (not shown). The 10-group lens L10 is a lens for focus adjustment, similar to the 8-group lens L8, and is driven in the optical axis direction by another linear vibration wave motor (not shown) held by the rear group base 104. This linear vibration wave motor is also electrically connected to the control board 107 by a flexible board (not shown). [[ID=']]

[0020] The 11-group lens L11 is held by the 11-group lens barrel 121. The 11-group lens barrel 121 is fixed to the rear group base 104. The cover member 123 is disposed on the object side of the 2-group lens barrel 112.

[0021] The 2-group lens L2, the 3-group lens L3, and the 4-group lens L4 are lenses that move during zooming, and cam followers (described later) are fixed to the 2-group lens barrel 112, the 3-group lens barrel 113, the 4-group lens barrel 114, and the cover member 123. Each cam follower engages with a plurality of straight grooves provided in the guide cylinder 102 and a plurality of cam grooves provided in the cam ring 105, and is configured to be able to move straight in the optical axis direction by rotating the cam ring 105. That is, the guide cylinder 102 guides the plurality of lens barrels and the cover member 123 in the optical axis direction. <&

[0022] Furthermore, the 8-group lens L8 and 10-group lens L10 used for focus adjustment are driven in the optical axis direction by linear vibration wave motors as the camera zooms. During zooming, the position information (focus position information) of the 8-group lens L8 and 10-group lens L10, which focus at each focal length from infinity to close, is stored as data. Based on this information and the focal length information detected by a zoom sensor (not shown), the 8-group lens L8 and 10-group lens L10 are driven and controlled.

[0023] Next, we will provide a detailed explanation of the configuration of the zoom group. Figures 3(A) and 3(B) are side views of the zoom group assembled in the cam ring 105 and guide tube 102, and Figures 3(A) and 3(B) show the view from different angles. Figures 4(A) and 4(B) are side views of the zoom group assembled in the guide tube 102, and Figures 4(A) and 4(B) show the view from different angles. Figure 5 is a front view of the zoom group only. Figure 6 is a side view of the zoom group only. Figure 7 is a rear view of the zoom group only.

[0024] The second lens barrel 112 is equipped with a second cam follower 112a (first cam follower), the third lens barrel 113 is equipped with a third cam follower 113a (second cam follower), the fourth lens barrel 114 is equipped with a fourth cam follower 114a (third cam follower), and the cover member 123 is equipped with a cover member cam follower 123a (fourth cam follower).

[0025] The cam ring 105 is provided with a second group cam groove 105a (first cam groove), a third group cam groove 105b (second cam groove), a fourth group cam groove 105c (third cam groove), and a cover member cam groove 105d (fourth cam groove). The guide cylinder 102 is provided with a second group straight groove 102a, a third group straight groove 102b, a fourth group straight groove 102c, and a cover member straight groove 102d (third straight groove). The second group cam follower 112a, a third group cam follower 113a, a fourth group cam follower 114a, and a cover member cam follower 123a are engaged with the second group cam groove 105a, the third group cam groove 105b, the fourth group cam groove 105c, and the cover member cam groove 105d, respectively. Furthermore, the cam followers 112a, 113a, 114a, and 123a of the cover member engage with the 2nd group straight groove 102a, the 3rd group straight groove 102b, the 4th group straight groove 102c, and the cover member straight groove 102d, respectively. In other words, the guide tube 102 has multiple straight grooves that guide the multiple lens barrels and the cover member 123 in the optical axis direction, and also restricts the movement of the cam ring 105 in the optical axis direction. Each of the multiple cam grooves engages with each of the multiple cam followers.

[0026] The 4-group cam groove 105c and the cover member cam groove 105d are cam grooves that integrate the cam shapes corresponding to the 4-group cam follower 114a and the cover member cam follower 123a. The object side functions as the contact surface for the 4-group cam follower 114a, and the image plane side functions as the contact surface for the cover member cam follower 123a. That is, the 4-group cam follower 114a provided on the 4-group lens barrel 114 and the cover member cam follower 123a provided on the cover member 123 are arranged inside the same integrated cam groove, the 4-group cam groove 105c and the cover member cam groove 105d. The 4-group cam follower 114a contacts the cam groove surface in the first direction D1 (the cam groove surface of the 4-group cam groove 105c), and the cover member cam follower 123a contacts the cam groove surface in the second direction D2, which is opposite to the first direction D1 (the cam groove surface of the cover member cam groove 105d).

[0027] The second lens group tube 112 and the third lens group tube 113 are biased toward each other by an inter-group biasing member 124 (first biasing member) which is a tension coil spring. Due to the biasing by the inter-group biasing member 124, the second-group cam follower 112a is moved toward the image plane side and the third-group cam follower 113a is moved toward the object side, and they come into contact with one surface of the cam groove or the straight groove.

[0028] The four-group lens barrel 114 and the cover member 123 are also biased toward each other by a four-group biasing member 125 (second biasing member) which is a tension coil spring. Due to the biasing by the four-group biasing member 125, the cover member cam follower 123a is moved toward the image plane side and the four-group cam follower 114a is moved toward the object side, and they come into contact with one surface of the cam groove and the straight groove.

[0029] In this embodiment, the biasing member is constructed using a tension coil spring, which is advantageous in terms of space saving, but it may also be constructed using a compression coil spring. All cam followers employ bearings and reduce zoom torque by rolling against the cam groove and linear groove. Furthermore, by suppressing the play between the cam follower and the cam groove and linear groove, focus shift due to hysteresis during zoom reversal and deterioration of optical performance are suppressed.

[0030] Next, we will explain the relationship between the trajectory of each zoom group and the rotational torque of the cam ring 105 due to the biasing force. Figure 8 is a graph of the amount of movement of each zoom group, Figure 9 is a graph of the relative movement of the zoom groups, Figure 10 is a graph of the intersection angle of each zoom group, and Figure 11 is a graph of the difference in intersection angle of the zoom groups.

[0031] As described above, the first lens barrel, which is a two-group lens barrel 112, the second lens barrel, which is a three-group lens barrel 113, the third lens barrel, which is a four-group lens barrel 114, and the cover member 123 that does not hold the lens groups are configured to be movable in the optical axis direction by the rotation of the cam ring 105.

[0032] In the conventional disclosed configuration, by biasing all between lens barrels, backlash suppression of the cam follower has been achieved with a minimum component configuration without adding components. On the other hand, when biasing between lens barrels, unless the amount of movement during zooming or the included angle of the cam grooves is approximated, self-running torque, which is the torque for rotating the cam ring, will occur.

[0033] The included angle is the angle formed by the cam groove provided in the cam ring and an axis in the direction orthogonal to the X-X axis, which is the optical axis. The self-running torque increases as the relative movement amount between the moving groups being biased is larger, or as the difference in the included angle of the cam grooves between the moving groups is larger. Furthermore, the self-running torque also increases as the biasing force is larger.

[0034] In an extension of the conventional disclosed configuration, in order to suppress the self-running torque, it is necessary to prevent the self-running of the cam ring by increasing the viscosity of the grease or the frictional force due to the biasing of operating parts such as the zoom ring, which results in an increase in the zoom torque.

[0035] Therefore, in this embodiment, in the three lens barrels that move in the optical axis direction during zooming, when the cam ring 105 is rotated from the wide end to the tele end, the maximum value of the relative movement amount between the 2-group lens barrel 112 and the 3-group lens barrel 113 based on the wide end is set as A. Also, when the maximum value of the relative movement amount between the 3-group lens barrel 113 and the 4-group lens barrel 114 based on the wide end is set as B, and the maximum value of the relative movement amount between the 2-group lens barrel 112 and the 4-group lens barrel 114 based on the wide end is set as C, A < B and A < C. And by adopting a configuration in which biasing is performed between the 2-group lens barrel 112 and the 3-group lens barrel 113 and between the 4-group lens barrel 114 and the cover member 123, a configuration for suppressing the self-running torque is realized. Therefore, an optical device capable of suppressing an increase in the zoom torque can be provided.

[0036] Similarly, from the perspective of the intersection angle, when the cam ring 105 is rotated from the wide end to the tele end, let the maximum value of the difference in the intersection angles between the two groups of cam grooves 105a and the three groups of cam grooves 105b among the plurality of cam grooves be D. Also, when the maximum value of the difference in the intersection angles between the three groups of cam grooves 105b and the four groups of cam grooves 105c is E, and the maximum value of the difference in the intersection angles between the two groups of cam grooves 105a and the four groups of cam grooves 105c is F, D < E and D < F. Then, it is biased between the two-group lens barrel 112 that moves along the two-group cam groove 105a and the three-group lens barrel 113 that moves along the three-group cam groove 105b. Further, by adopting a configuration in which it is biased between the four-group lens barrel 114 that moves along the four-group cam groove 105c and the cover member 123, a configuration that suppresses the self-running torque is realized. Therefore, an optical device capable of suppressing an increase in zoom torque can be provided.

[0037] In either perspective, the configuration in which biasing is applied between the two-group lens barrel 112 and the three-group lens barrel 113 can most effectively suppress the self-running torque. Also, the four-group cam groove 105c is provided with surfaces against which the cover member cam follower 123a and the four-group cam follower 114a respectively abut. Since the cam shapes are the same, a configuration is adopted in which no self-running torque is generated due to biasing.

[0038] In this embodiment, the cover member 123 and the four-group lens barrel 114 are configured to be biased by the same cam. However, the influence of the 2-3 group self-running torque (first torque) that rotates the cam ring 105, which occurs when biasing between the two-group lens barrel 112 and the three-group lens barrel 113, may not be negligible. In such a case, the cam locus corresponding to the cover member cam follower 123a of the cover member 123 is changed. And it is possible to adopt a configuration in which the self-running torque (second torque) that rotates the cam ring 105, which occurs when biasing between the cover member 123 and the four-group lens barrel 114, cancels out the 2-3 group self-running torque. Specifically, it is set in a direction to cancel the self-running torque with respect to the 2-3 group self-running torque. By adopting the above configuration, further suppression of the zoom torque can be realized.

[0039] As shown in Figure 1, the cover member 123, the second lens group 112, the third lens group 113, and the fourth lens group 114 are arranged in order from the object side. The second lens group 112 and the third lens group 113 are adjacent in the optical axis direction and are biased by the inter-group biasing member 124, which biases the cover member 123 and the fourth lens group 114 so as to sandwich the two groups. The third lens group 113 and the fourth lens group 114 are also adjacent in the optical axis direction. The cover member 123 is positioned closest to the object in the optical axis direction and is adjacent to the second lens group 112.

[0040] The cover member 123 is positioned in front of the 2-group lens barrel 112, rather than between the 3-group lens barrel 113 and the 4-group lens barrel 114. The positions of the cam followers are such that the 2-group cam follower 112a is on the image plane side relative to the lens holder of the 2-group lens L2, and the 4-group cam follower 114a is on the object side relative to the lens holder of the 4-group lens L4. This reduces the clearance between the 3-group lens barrel 113 and the 4-group lens barrel 114 in the telephoto setting, thus enabling a smaller overall lens barrel size.

[0041] Furthermore, as shown in Figure 1, a cross-sectional view perpendicular to the optical axis, the 4-group lens barrel 114 is arranged superimposed on the 2-group lens barrel 112 and the 3-group lens barrel 113, resulting in a configuration that minimizes the clearance between the lens barrels in the direction of the optical axis, thus achieving miniaturization. Alternatively, in a cross-section perpendicular to the optical axis, two or more lens barrels from the 2-group lens barrel 112 to the 4-group lens barrel 114 may be superimposed.

[0042] As shown in Figure 8, the amount of movement of the cover member 123 in the optical axis direction due to the rotation of the cam ring 105 during zooming is smaller than the amount of movement of the 2-group lens barrel 112 in the optical axis direction due to the rotation of the cam ring 105 during zooming. In other words, the cover member 123, which is positioned closest to the object, is always positioned closest to the object among the zoom group. Furthermore, when the cam ring 105 is rotated from the wide end to the telephoto end, the amount of movement of the 4-group lens barrel 114 in the optical axis direction is the same as the amount of movement of the cover member 123 in the optical axis direction, and the 4-group lens barrel 114 and the cover member 123 follow the same movement trajectory. In other words, during zooming, the distance between the 4-group lens barrel 114 and the cover member 123 in the direction along the optical axis can be kept constant.

[0043] As shown in Figure 1, the cover member 123 is provided with a light-shielding portion that functions as a light-shielding shape, and the light-shielding portion limits the range of light rays that hit the light-shielding line 102e provided in the inner diameter of the guide tube 102. The light-shielding line 102e is provided to suppress ghosting, which is caused by light incident from the first group lens L1 being reflected and formed on an imaging surface (not shown). The wider the range illuminated by the light-shielding line 102e, the greater the range of ghosting and the worse the intensity of the ghosting. However, in this embodiment, the light-shielding portion of the cover member 123, which has a small amount of movement during zooming, can limit the range of light rays that hit the light-shielding line 102e, thus having the effect of suppressing ghosting.

[0044] As shown in Figure 6, when viewed from the optical axis direction, the intergroup biasing member 124 is positioned between the 2-group cam follower 112a provided on the 2-group lens barrel 112 and the 3-group cam follower 113a provided on the 3-group lens barrel 113. This arrangement prevents the lens barrel from deforming, for example, if the biasing member were positioned at a phase away from the cam follower. This would generate a moment in the lens barrel corresponding to the distance between the cam follower and the biasing member.

[0045] Similarly, when viewed from the optical axis direction, the 4-group biasing member 125 is positioned between the 4-group cam follower 114a provided on the 4-group lens barrel 114 and the cover member cam follower 123a provided on the cover member 123. This arrangement prevents deformation of the 4-group lens barrel 114 and the cover member 123, for example.

[0046] As mentioned above, the optical axis positions of the cover member 123 and the 4-group lens barrel 114 are determined by the contact of their respective cam followers with the 4-group cam groove 105c. However, if an impact greater than the biasing force of the 4-group biasing member 125 is applied, they will move between the 4-group cam groove 105c.

[0047] In particular, in the middle of the zoom range, each lens group has degrees of freedom in the optical axis direction and rotation direction, so shock absorbers are necessary. For this reason, the 4-group lens barrel 114 is provided with a front shock absorber 114c (contact surface) and a rear shock absorber 114d (contact surface) for the 4-group lens barrel, both in the optical axis direction. In addition, the cover member 123 is provided with a front shock absorber 123c (contact surface) and a rear shock absorber 123d (contact surface) for the cover member, both in the optical axis direction, and a circumferential shock absorber 123e for the cover member, which are shock absorbers for the 4-group lens barrel 114.

[0048] In the event of an impact in the optical axis direction, the front impact receiver 114c of the 4th group and the front impact receiver 123c of the cover member, or the rear impact receiver 114d of the 4th group and the rear impact receiver 123d of the cover member, will come into contact, preventing unintended damage to components. In other words, between the 4th group lens barrel 114 and the cover member 123, there are contact surfaces that come into contact only during impacts, at the front and rear of the optical axis direction, respectively. In the event of an impact perpendicular to the optical axis, the circumferential impact receiver 114e of the 4th group and the circumferential impact receiver 123e of the cover member will come into contact, preventing unintended damage to components.

[0049] As shown in Figure 7, when viewed from the image plane side, the 4-group lens barrel 114 is provided with a 4-group recess 114f, through which the 2-group lens barrel 112 and the 3-group lens barrel 113 are exposed, allowing for positioning using a jig during assembly. Furthermore, the 4-group lens barrel 114 is provided with a 4-group positioning hole 114b, and the 2-group lens barrel 112 is provided with a 2-group positioning hole 112b, allowing for simple positioning of the lens barrels by providing a pin on the jig.

[0050] As mentioned above, the amount of movement of the 4-group lens barrel 114 is small, so the length of each linear groove 102c and the cover member linear groove 102d are also short, as shown in Figure 4(b). The 4-group linear groove 102c, which the 4-group cam follower 114a of the 4-group lens barrel 114 located on the guide tube 102 contacts, is located on the object side. The zoom key (not shown) is located in the range where the 4-group linear groove 102c and the cover member linear groove 102d are not provided at the optical axis position, and its phase as viewed from the optical axis direction is located between the 2-group linear groove 102a and the 3-group linear groove 102b. In other words, the movement range R of the zoom key that rotationally connects the operating part and the cam ring 105 is located in the range where the 4-group linear groove 102c is not provided.

[0051] By adopting the above configuration, the movement range R of the zoom key and the arrangement range of the straight grooves of some of the zoom groups can be superimposed, thereby enabling miniaturization of the optical device. Up to this point, we have explained the biasing method for a configuration with three movement groups and one cover member 123, but even when there are four movement groups, the zoom torque can be reduced by applying the same concept.

[0052] In addition to the aforementioned zoom groups of lens barrels 112 (2nd group), 113 (3rd group), and 114 (4th group), if a fourth lens barrel, a fifth group, 115, also becomes part of the zoom group, the relative movement of the moving groups, or the difference in the intersection angles of each group, can be calculated, and the combination with the smallest difference can be selected. That is, when the cam ring 105 is rotated from the wide end to the telephoto end, each lens barrel may be biased by the combination of the two lens barrels that have the smallest maximum relative movement of the first to fourth lens barrels relative to the wide end. Alternatively, the combination may be one in which the self-propelled torque of the first combination and the self-propelled torque of the second combination cancel each other out when biased between the moving groups. That is, when the cam ring 105 is rotated from the wide end to the telephoto end, with respect to the wide end, if the intersection angle is defined as the angle between the cam groove and the axis perpendicular to the optical axis (XX axis), each lens barrel may be biased by the combination of two lens barrels that move along the two cam grooves that have the smallest difference in the intersection angles among the multiple cam grooves.

[0053] Although preferred embodiments of the present invention have been described above, the invention is not limited to these embodiments, and various modifications and changes are possible within the scope of its gist. In this embodiment, when biasing moving groups that move with zoom, the self-propelled torque can be suppressed by biasing with a combination of small relative movement amounts of the zoom groups or small differences in the intersection angles of each group, thereby providing an optical device that can suppress the increase in zoom torque.

[0054] As described above, the optical device of the present invention can suppress self-propelled torque and suppress the increase in zoom torque even when the moving groups are biased against each other. Although interchangeable lenses were described in the above embodiment, the invention can also be applied to imaging devices integrally provided with the camera body, as well as to digital still cameras and video cameras.

[0055] Figure 12 is a schematic diagram showing an example configuration of a camera device 200 (imaging device) using an optical device to which the present invention is applied. The imaging device is configured to include a camera body 200a having a lens unit 100 and an image sensor 200b for capturing an image of an object formed by the lens unit 100. Alternatively, the imaging device may be configured such that the lens unit 100 is detachably attached to the camera body 200a of the camera device 200.

[0056] This embodiment includes the following configuration. (Composition 1) The first lens barrel, The second lens barrel, The third lens barrel, Multiple lens barrels including, Cover member and It has multiple cam grooves and a cam ring that can rotate around the optical axis, The plurality of lens barrels and the cover member have a plurality of straight grooves that guide them in the optical axis direction, and a guide cylinder that restricts the movement of the cam ring in the optical axis direction, An optical device having a plurality of cam followers that engage with each of the plurality of cam grooves, The rotation of the cam ring allows the plurality of lens barrels and the cover member to move in the direction of the optical axis via the cam follower. When the cam ring is rotated from the wide end to the telephoto end, with respect to the wide end, Let A be the maximum value of the relative movement between the first lens barrel and the second lens barrel. The maximum value of the relative movement between the second lens barrel and the third lens barrel is B. The maximum value of the relative movement between the first lens barrel and the third lens barrel is C. In that case, A <BかつA<Cであり、 An optical device characterized in that the first lens barrel and the second lens barrel are biased toward each other, and the third lens barrel and the cover member are biased toward each other. (Configuration 2) The first lens barrel, The second lens barrel, The third lens barrel, Multiple lens barrels including, Cover member and It has multiple cam grooves and a cam ring that can rotate around the optical axis, The plurality of lens barrels and the cover member have a plurality of straight grooves that guide them in the optical axis direction, and a guide cylinder that restricts the movement of the cam ring in the optical axis direction, An optical device having a plurality of cam followers that engage with each of the plurality of cam grooves, The rotation of the cam ring allows the plurality of lens barrels and the cover member to move in the direction of the optical axis via the cam follower. When the angle between the cam groove and the axis perpendicular to the optical axis is defined as the intersection angle, When the cam ring is rotated from the wide end to the telephoto end, D is the maximum value of the difference in the intersection angle between the first cam groove and the second cam groove among the plurality of cam grooves. E is the maximum value of the difference in the intersection angle between the second cam groove and the third cam groove. When F is the maximum value of the difference in the intersection angle between the first cam groove and the third cam groove, D <EかつD<Fであり、 An optical device characterized in that the first lens barrel, which moves along the first cam groove, and the second lens barrel, which moves along the second cam groove, are biased toward each other, and the third lens barrel, which moves along the third cam groove, and the cover member are biased toward each other. (Composition 3) The first lens barrel, The second lens barrel, The third lens barrel, The fourth lens barrel, Multiple lens barrels including, It has multiple cam grooves and a cam ring that can rotate around the optical axis, The plurality of lens barrels have a plurality of straight grooves that guide them in the optical axis direction, and a guide tube that restricts the movement of the cam ring in the optical axis direction, An optical device having a plurality of cam followers that engage with each of the plurality of cam grooves, The rotation of the cam ring allows the plurality of lens barrels to be moved in the direction of the optical axis via the cam follower. When the cam ring is rotated from the wide end to the telephoto end, with respect to the wide end, The combination of two lens barrels that has the smallest maximum relative movement among multiple lens barrels, or An optical device characterized in that, when the angle between the cam groove and the axis perpendicular to the optical axis is defined as the intersection angle, each lens barrel is biased by a combination of two lens barrels that move along the two cam grooves among the plurality of cam grooves whose respective intersection angles are the smallest. (Composition 4) The optical apparatus according to configuration 1 or 2, characterized in that the first lens barrel and the second lens barrel, and the second lens barrel and the third lens barrel are adjacent to each other in the optical axis direction, and the cover member is positioned closest to the object in the optical axis direction and is adjacent to the first lens barrel. (Composition 5) The optical apparatus according to configuration 1 or 2, characterized in that the amount of movement of the cover member in the optical axis direction due to the rotation of the cam ring is smaller than the amount of movement of the first lens barrel in the optical axis direction due to the rotation of the cam ring. (Composition 6) The third cam follower provided in the third lens barrel and the fourth cam follower provided in the cover member are arranged inside the same cam groove. The optical device according to configuration 1 or 2, characterized in that the third cam follower abuts against the cam groove surface in the first direction, and the fourth cam follower abuts against the cam groove surface in the second direction, which is opposite to the first direction. (Composition 7) The optical device according to configuration 1 or 2, characterized in that contact surfaces that come into contact only during impact are provided between the third lens barrel and the cover member, on the front and rear sides in the optical axis direction. (Composition 8) The first cam follower of the first lens barrel is positioned on the image plane side of the lens holding portion of the first lens barrel. The third cam follower of the third lens barrel is positioned on the object side of the lens holding portion of the third lens barrel. The optical device according to any one of configurations 1 to 7, characterized in that the first lens barrel and the third lens barrel are superimposed in a cross-section perpendicular to the optical axis. (Composition 9) The third straight groove, which the third cam follower of the third lens barrel positioned in the guide tube contacts, is located on the object side. The optical device according to any one of configurations 1 to 8, characterized in that the range of movement of the zoom key that rotationally connects the operating section and the cam ring is located in a range where the third straight groove is not provided. (Composition 10) The optical device according to any one of configurations 1 to 9, characterized in that the first biasing member for biasing the first lens barrel and the second lens barrel is positioned between a first cam follower provided on the first lens barrel and a second cam follower provided on the second lens barrel when viewed from the direction of the optical axis. (Composition 11) The optical apparatus according to configuration 1 or 2, characterized in that the second biasing member that biases the third lens barrel and the cover member is positioned between a third cam follower provided on the third lens barrel and a fourth cam follower provided on the cover member when viewed from the direction of the optical axis. (Composition 12) An optical device according to any one of configurations 1 to 10, characterized in that, in a cross section perpendicular to the optical axis, two or more lens barrels from the first to the third lens barrels are superimposed. (Composition 13) The first torque that rotates the cam ring when the first lens barrel and the second lens barrel are biased, The second torque that rotates the cam ring, which is generated when the third lens barrel and the cover member are biased, The optical device according to configuration 1 or 2, characterized in that the second torque is in a direction that cancels out the first torque. (Composition 14) The optical device according to configuration 1 or 2, characterized in that when the cam ring is rotated from the wide end to the telephoto end, the movement trajectories of the third lens barrel and the cover member are the same. (Composition 15) The optical device according to any one of configurations 1 to 3, characterized in that the third cam groove and the fourth cam groove among the plurality of cam grooves are cam grooves that integrate the cam shapes corresponding to the third cam follower and the fourth cam follower. (Composition 16) An imaging device characterized by including an optical device described in any of configurations 1 to 3 and an image sensor for capturing an image formed by the optical device. [Explanation of Symbols]

[0057] 1. Zoom lens (optical device) 102 Guide tube 102a Group 2 straight grooves (straight grooves) 102b 3-group straight groove (straight groove) 102c 4-group straight groove (straight groove) 102d Cover member straight groove (third straight groove) 105 Cam ring 105a 2-group cam groove (first cam groove) 105b 3-group cam groove (second cam groove) 105c 4-group cam groove (third cam groove) 105d Cover member cam groove (fourth cam groove) 112 2-group telescope tube (first lens tube) 112a Group 2 Cam Follower (First Cam Follower) 113 3-group telescope tube (second lens tube) 113a 3-group cam follower (second cam follower) 114 4-group telescope tube (third lens tube) 114a 4-group cam follower (third cam follower) 115 5-group telescope tube (fourth lens tube) 123 Cover component 123a Cover member cam follower (fourth cam follower) 124 Intergroup biasing member (first biasing member) 125 4-group biasing member (second biasing member) 123c Front impact receiver (contact surface) of cover member 123d Rear impact receiver (contact surface) of cover member 114c 4th group front impact receiver (contact surface) 114d 4th group rear impact receiver (contact surface) 200 Camera equipment (imaging device) D1 First direction D2 Second direction R Movement range

Claims

1. The first lens barrel, The second lens barrel, The third lens barrel, Multiple lens barrels including, Cover member and It has multiple cam grooves and a cam ring that can rotate around the optical axis, The plurality of lens barrels and the cover member have a plurality of straight grooves that guide them in the optical axis direction, and a guide cylinder that restricts the movement of the cam ring in the optical axis direction, An optical device having a plurality of cam followers that engage with each of the plurality of cam grooves, The rotation of the cam ring allows the plurality of lens barrels and the cover member to move in the direction of the optical axis via the cam follower. When the cam ring is rotated from the wide end to the telephoto end, with respect to the wide end, The maximum value of the relative movement between the first lens barrel and the second lens barrel is A. The maximum value of the relative movement between the second lens barrel and the third lens barrel is B. The maximum value of the relative movement between the first lens barrel and the third lens barrel is C. When this is the case, A < B and A < C, An optical device characterized in that the first lens barrel and the second lens barrel are biased toward each other, and the third lens barrel and the cover member are biased toward each other.

2. The first lens barrel, The second lens barrel, The third lens barrel, Multiple lens barrels including, Cover member and It has multiple cam grooves and a cam ring that can rotate around the optical axis, The plurality of lens barrels and the cover member have a plurality of straight grooves that guide them in the optical axis direction, and a guide cylinder that restricts the movement of the cam ring in the optical axis direction, An optical device having a plurality of cam followers that engage with each of the plurality of cam grooves, The rotation of the cam ring allows the plurality of lens barrels and the cover member to move in the direction of the optical axis via the cam follower. When the angle between the cam groove and the axis perpendicular to the optical axis is defined as the intersection angle, When the cam ring is rotated from the wide end to the telephoto end, D is the maximum value of the difference in the intersection angle between the first cam groove and the second cam groove among the plurality of cam grooves. E is the maximum value of the difference in the intersection angle between the second cam groove and the third cam groove. When F is the maximum value of the difference in the intersection angle between the first cam groove and the third cam groove, D < E and D < F, An optical device characterized in that the first lens barrel, which moves along the first cam groove, and the second lens barrel, which moves along the second cam groove, are biased toward each other, and the third lens barrel, which moves along the third cam groove, and the cover member are biased toward each other.

3. The first lens barrel, The second lens barrel, The third lens barrel, The fourth lens barrel, Multiple lens barrels including, It has multiple cam grooves and a cam ring that can rotate around the optical axis, The plurality of lens barrels have a plurality of straight grooves that guide them in the optical axis direction, and a guide tube that restricts the movement of the cam ring in the optical axis direction, An optical device having a plurality of cam followers that engage with each of the plurality of cam grooves, The rotation of the cam ring allows the plurality of lens barrels to be moved in the direction of the optical axis via the cam follower. When the cam ring is rotated from the wide end to the telephoto end, with respect to the wide end, The combination of two lens barrels that has the smallest maximum relative movement among multiple lens barrels, or An optical device characterized in that, when the angle between the cam groove and the axis perpendicular to the optical axis is defined as the intersection angle, each lens barrel is biased by a combination of two lens barrels that move along the two cam grooves among the plurality of cam grooves whose respective intersection angles are the smallest.

4. The optical apparatus according to claim 1 or 2, characterized in that the first lens barrel and the second lens barrel, and the second lens barrel and the third lens barrel are adjacent to each other in the optical axis direction, and the cover member is positioned closest to the object in the optical axis direction and is adjacent to the first lens barrel.

5. The optical apparatus according to claim 1 or 2, characterized in that the amount by which the cover member moves in the optical axis direction due to the rotation of the cam ring is smaller than the amount by which the first lens barrel moves in the optical axis direction due to the rotation of the cam ring.

6. The third cam follower provided in the third lens barrel and the fourth cam follower provided in the cover member are arranged inside the same cam groove. The optical apparatus according to claim 1 or 2, characterized in that the third cam follower abuts against the cam groove surface in the first direction, and the fourth cam follower abuts against the cam groove surface in the second direction, which is opposite to the first direction.

7. The optical apparatus according to claim 1 or 2, characterized in that contact surfaces that come into contact only during impact are provided between the third lens barrel and the cover member, on the front and rear sides in the optical axis direction.

8. The first cam follower of the first lens barrel is positioned on the image plane side of the lens holding portion of the first lens barrel. The third cam follower of the third lens barrel is positioned on the object side of the lens holding portion of the third lens barrel. The optical apparatus according to any one of claims 1 to 3, characterized in that the first lens barrel and the third lens barrel are superimposed in a cross-section perpendicular to the optical axis.

9. The third straight groove, which the third cam follower of the third lens barrel positioned in the guide tube contacts, is located on the object side. The optical apparatus according to any one of claims 1 to 3, characterized in that the range of movement of the zoom key that rotationally connects the operating section and the cam ring is located in a range where the third straight groove is not provided.

10. The optical apparatus according to any one of claims 1 to 3, characterized in that the first biasing member for biasing the first lens barrel and the second lens barrel is positioned between a first cam follower provided on the first lens barrel and a second cam follower provided on the second lens barrel when viewed from the direction of the optical axis.

11. The optical apparatus according to claim 1 or 2, characterized in that the second biasing member that biases the third lens barrel and the cover member is positioned between a third cam follower provided on the third lens barrel and a fourth cam follower provided on the cover member when viewed from the direction of the optical axis.

12. The optical apparatus according to any one of claims 1 to 3, characterized in that, in a cross section perpendicular to the optical axis, two or more lens barrels from the first to the third lens barrels are superimposed.

13. The first torque that rotates the cam ring when the first lens barrel and the second lens barrel are biased, The second torque that rotates the cam ring, which is generated when the third lens barrel and the cover member are biased, The optical device according to claim 1 or 2, characterized in that the second torque is in a direction that cancels out the first torque.

14. The optical device according to claim 1 or 2, characterized in that when the cam ring is rotated from the wide end to the telephoto end, the movement trajectories of the third lens barrel and the cover member are the same.

15. The optical device according to any one of claims 1 to 3, characterized in that the third cam groove and the fourth cam groove among the plurality of cam grooves are cam grooves that integrate cam shapes corresponding to the third cam follower and the fourth cam follower.

16. An imaging device comprising an optical device according to any one of claims 1 to 3 and an image sensor for capturing an image formed by the optical device.

Images