Lens barrel, lens device, and imaging apparatus

Abstract

To provide a lens barrel capable of miniaturization while maintaining with high accuracy the relative positions of respective lens groups in a first optical system and a second optical system.SOLUTION: A lens barrel of a lens device having a first optical system and a second optical system which are arranged in parallel with respect to an imaging element and guide light to the imaging element comprises: an integrated holding member that is integrally formed to hold an eleventh lens group included in the first optical system and a twenty-first lens group included in the second optical system and corresponding to the eleventh lens group; a first holding member that holds a twelfth lens group included in the first optical system; a second holding member that holds a twenty-second lens group included in the second optical system and corresponding to the twelfth lens group; and a base barrel to which the integrated holding member, the first holding member, and the second holding member are fixed.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] There is known a technique for performing stereoscopic photography using an imaging device in which two optical systems are arranged horizontally. Patent Document 1 discloses a technique for controlling the focusing of a pair of left and right lens barrels. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 8-242468 Summary of the Invention [Problem to be solved by the invention]

[0004] Patent Document 1 discloses a technology for an imaging device using a first lens barrel for the right eye and a second lens barrel for the left eye, in which focus information for the first lens barrel is calculated and focus adjustment for the second lens barrel is performed based on that information.

[0005] When a viewer views with their right and left eyes an image formed on an imaging element by the first optical system of the first lens barrel and an image formed on an imaging element by the second optical system of the second lens barrel, respectively, the images are fused and can be perceived as a three-dimensional image. However, if the difference in the relative positions of each lens group and the imaging element becomes large due to manufacturing errors such as the dimensions of the components that make up each lens barrel and the assembly of those components, the viewer will be more likely to notice a difference in image quality between the images for the right eye and the left eye. If this difference in image quality is large, the viewer will have difficulty fusing the images for the left and right eyes, which can cause greater fatigue when viewing.

[0006] Furthermore, increasing the lens diameter to improve optical performance is constrained by the thickness of the lens holding barrel at the closest point between the first and second optical systems under the condition of the width between the left and right eyes (baseline length).

[0007] An object of the present invention is to provide a lens barrel that can be made compact while maintaining the relative positions of the lens groups in the first optical system and the second optical system with high precision. [Means for solving the problem]

[0008] In order to achieve the above object, the lens barrel of the present invention is a lens barrel of a lens device having a first optical system and a second optical system arranged in parallel to an image sensor, each of which guides light to the image sensor, and is characterized by having an integrally formed integral holding member that holds an 11th lens group included in the first optical system and a 21st lens group included in the second optical system and corresponding to the 11th lens group, a first holding member that holds a 12th lens group included in the first optical system, a second holding member that holds a 22nd lens group included in the second optical system and corresponding to the 12th lens group, and a base barrel to which the integral holding member, the first holding member, and the second holding member are fixed. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a lens barrel that can be made compact while maintaining the relative positions of the lens groups in the first optical system and the second optical system with high precision. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a cross-sectional view of an interchangeable lens for a single-lens reflex camera equipped with a lens barrel according to an embodiment, and a camera body; [Figure 2] 1 is a perspective view of a first group barrel 111 according to an embodiment of the present invention; [Figure 3] Horizontal cross-sectional view of the first group barrel 111 of the embodiment DETAILED DESCRIPTION OF THE INVENTION

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A lens barrel 100, a lens device, and an imaging device according to embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The present invention relates to a lens barrel, a lens device, and an imaging device that are capable of taking stereoscopic photographs by moving at least a portion of a first optical system and a second optical system, which are arranged in parallel to an imaging element and each guide light to the imaging element, in the optical axis direction to adjust zoom and focus. [Example]

[0012] A lens barrel 100 according to an embodiment of the present invention will now be described. FIG. 1 is a cross-sectional view of an imaging device that includes an interchangeable lens (lens device) for a single-lens reflex camera that includes a lens barrel 100 according to an embodiment of the present invention, and an imaging element 202 that captures an image formed by the lens. The line indicated by Xa-Xa in the figure represents the optical axis of the first optical system that forms an image for the left eye. The line indicated by Xb-Xb in the figure represents the optical axis of the second optical system that forms an image for the right eye. The line indicated by XX in the figure represents the optical axis of the entire lens barrel 100, which is the center between Xa-Xa and Xb-Xb. In the following explanation, elements related to the first optical system will be designated by reference signs that end with a, and elements related to the second optical system will be designated by reference signs that end with b.

[0013] Mount 101 provided on lens barrel 100 is a component having a bayonet portion for attachment to camera mount 201 provided on camera body 200. Guide barrel 102 is fixed integrally to mount 101 together with outer barrel 104. Cam barrel 103 is held on the outer periphery of guide barrel 102 so as to be able to rotate freely around the optical axis. Cam barrel 103 is connected by a gear to a stepping motor unit (not shown) held on the image side end of guide barrel 102. Cam barrel 103 is configured to rotate when the stepping motor unit rotates in response to control information from control board 108.

[0014] A contact block 109 is electrically connected to the control board 108, and the control board 108 communicates with the camera body 200 via the contact block 109 and receives power from the camera body 200. When a shutter button provided on the camera body 200 is operated, a camera control circuit 203 controls the image sensor 202 so as to capture an image formed on the image sensor 202 by the first optical system and the second optical system. The first optical system and the second optical system are arranged in parallel with the image sensor 202, so that two image circles are formed in parallel on the image sensor 202. A CCD (Charge Coupled Device), CMOS (Complementary Metal Oxide Semiconductor), or the like is used as the image sensor 202.

[0015] The first optical system and the second optical system are optically configured with similar lens groups and are arranged with a fixed interval (baseline length) between them on the left and right. The front cover glass 107 held by the filter frame 106 fixed with screws to the guide tube 102 is intended to protect the inside of the lens barrel and has no optical function. The first optical system for the left eye and the second optical system for the right eye are arranged on the image side of the cover glass 107.

[0016] The first optical system includes, from the object side to the image side, a first left lens group (eleventh lens group) L1a, a second left lens group (twelfth lens group) L2a, a third left lens group (twelfth lens group) L3a, and a fourth left lens group (twelfth lens group) L4a. The second optical system includes, from the object side to the image side, a first right lens group (twenty-first lens group) L1b, a second right lens group (twenty-second lens group) L2b, a third right lens group (twenty-second lens group) L3b, and a fourth right lens group (twenty-second lens group) L4b. Optically, the first group left lens L1a corresponds to the first group right lens L1b, the second group left lens L2a corresponds to the second group right lens L2b, the third group left lens L3a corresponds to the third group right lens L3b, and the fourth group left lens L4a corresponds to the fourth group right lens L4b.

[0017] The first group left lens L1a of the first optical system and the first group right lens L1b of the second optical system are both lens groups located closest to the object, and are held by a first group barrel (integral holding member) 111, which serves as a lens holding frame made of a single, integrated member. The first group barrel 111 is then fixed to a main base (base barrel) 116 with screws in the optical axis direction.

[0018] The second-group left lens (twelfth lens group) L2a is held in the second-group left barrel (first holding member) 112a. The second-group right lens (twenty-second lens group) L2b is held in the second-group right barrel (second holding member) 112b. Three second-group eccentric rollers 112c are fixed to each of the second-group left barrel 112a and the second-group right barrel 112b with screws at approximately 120-degree intervals around the circumference of the lens barrel 100. The second-group eccentric rollers 112c have a cylindrical portion that is eccentric with respect to the central axis of the screw that secures them to the second-group left barrel 112a or the second-group right barrel 112b. The cylindrical portion engages with a second-group eccentric roller engagement groove 111c (see FIG. 3) provided in the first-group barrel 111. By rotating the second group eccentric roller 112c around the axis of the screw, the axial position relative to the second group eccentric roller engagement groove 111c changes within a plane whose normal is perpendicular to the optical axis.

[0019] Therefore, the second-group left barrel 112a and the second-group right barrel 112b are each configured so that their relative positions with respect to the first-group barrel 111 can be changed. As a result, the positions of the second-group left lens L2a and the second-group right lens L2b in the optical axis direction, decentering direction, and tilt direction can be changed with respect to the first-group left lens L1a and the first-group right lens L1b held in the first-group barrel 111. This enables optical adjustment to correct positional deviation in the optical axis direction or optical axis deviation that occurs in the lens groups due to manufacturing errors.

[0020] The fourth-group left lens (twelfth lens group) L4a is held by a fourth-group left barrel (first holding member) 114a. The fourth-group right lens (twelfth lens group) L4b is held by a fourth-group right barrel (second holding member) 114b. Three fourth-group eccentric rollers 114c are fixed to each of the fourth-group left barrel 114a and the fourth-group right barrel 114b with screws at approximately 120-degree intervals around the circumference. The fourth-group eccentric rollers 114c have a cylindrical portion that is eccentric with respect to the central axis of the screw that secures them to the fourth-group left barrel 114a or the fourth-group right barrel 114b. The cylindrical portion engages with a fourth-group eccentric roller engagement groove 116c provided in the main base 116. By rotating the fourth-group eccentric roller 114c around the axis of the screw, the axial position of the fourth-group eccentric roller 114c relative to the fourth-group eccentric roller engagement groove 116c changes within a plane whose normal is perpendicular to the optical axis.

[0021] Therefore, it is possible to change the relative positions of the fourth-group left barrel 114a and the fourth-group right barrel 114b with respect to the first-group barrel 111 fixed to the main base 116. As a result, it is possible to change the positions of the fourth-group left lens L4a and the fourth-group right lens L4b in the optical axis direction, decentering direction, and tilt direction with respect to the first-group left lens L1a and the first-group right lens L1b held in the first-group barrel 111. This enables optical adjustment to correct positional deviation in the optical axis direction or optical axis deviation that occurs in the lens groups due to manufacturing errors.

[0022] The third group left lens (twelfth lens group) L3a is held in a third group left barrel (first holding member) 113a. The third group left barrel 113a is fixed to the main base 116 with screws. The third group right lens (twenty-second lens group) L3b is held in a third group right barrel (second holding member) 113b. The third group right barrel 113b is supported by two guide bars (not shown) that extend in the optical axis direction so as to be movable in the optical axis direction. The two guide bars are held by the first group barrel 111 and the main base 116.

[0023] A stepping motor 119 having a lead screw is fixed to the main base 116 with a screw. A rack (not shown) that engages with the lead screw of the stepping motor 119 is held by the third-group right barrel 113b. When the stepping motor 119 rotates based on a control signal from the control board 108, the rack is driven, and the third-group right barrel 113b moves forward and backward in the optical axis direction relative to the main base 116.

[0024] The electromagnetic diaphragm unit (light amount adjustment unit) 115 is held by the first group barrel 111 and the main base 116. The electromagnetic diaphragm unit 115 has a first opening through which light rays from the first optical system pass and a second opening through which light rays from the second optical system pass, and each of the first opening and the second opening is provided with a plurality of diaphragm blades. The plurality of diaphragm blades of each of the first opening and the second opening are driven by a diaphragm drive motor controlled by the control board 108, and the amount of light reaching the image sensor 202 is adjusted by changing the area of ​​the opening.

[0025] An image is formed on the image sensor 202 by the first and second optical systems. Manufacturing errors, such as deviations in the dimensions of each component from the design values ​​or deviations in the mounting position during assembly, can result in degradation of the optical performance of the image obtained on the image sensor 202. Optical adjustment of the second-group left lens L2a and second-group right lens L2b using the aforementioned second-group eccentric roller 112c, and optical adjustment of the fourth-group left lens L4a and fourth-group right lens L4b using the fourth-group eccentric roller 114c, can bring the optical performance closer to the design values. Furthermore, if there is a focus difference between the images for the left and right eyes due to factors such as relative positional deviations between the first and second optical systems or tilt with respect to the image sensor 202, these can be adjusted by moving the third-group right lens L3b back and forth along the optical axis using the stepping motor 119.

[0026] Cam followers 116d are provided on the main base 116 at approximately 120-degree intervals in the circumferential direction. The cam followers 116d are engaged with rectilinear grooves 102c provided in the guide barrel 102 and extending in the optical axis direction, and with cam grooves 103c provided in the cam barrel 103. When the cam barrel 103 rotates relative to the guide barrel 102, the cam followers 116d advance and retreat in the optical axis direction. As already explained, the main base 116 holds the lens groups of the first optical system and the second optical system, and therefore, when the cam followers 116d advance and retreat, the lens groups of the first optical system and the second optical system can move together in the optical axis direction relative to the image sensor 202.

[0027] When a control signal is sent to the gear unit based on focus information obtained by processing an image from the image sensor 202 in the camera control circuit 203 and the cam ring rotates, the cam follower 116d advances and retreats along the optical axis, thereby performing a focusing operation. Alternatively, when the photographer rotates the focus operation ring 105 around the optical axis, a control signal is sent from the control board 108 to the gear unit in accordance with the amount of rotation detected by a focus operation ring rotation sensor (not shown), causing the cam barrel 103 to rotate. This also allows the cam follower 116d to advance and retreat, thereby performing a focusing operation.

[0028] It should be noted that, although a stepping motor 119 with a lead screw is used to drive the third group right barrel 113b, and a gear-coupled stepping motor unit is used to rotate the cam barrel 103, the configuration of the present invention is not limited to this. For example, a DC motor or an ultrasonic motor may also be used for drive.

[0029] FIG. 2 is a perspective view of the first-group lens barrel 111 of this embodiment. The first-group lens barrel 111 holds the first-group left lens L1a and the first-group right lens L1b. By holding the first-group left lens L1a and the first-group right lens L1b in a single component in this way, it is possible to reduce lens positional deviation relative to the image sensor 202 compared to when each lens is held in a separate lens barrel. When held in separate lens barrels, in addition to dimensional deviations of the components of each lens barrel, relative positional deviation occurs when each lens barrel is fixed to the main base 116. However, when the left and right eyes are held in a single integrated lens barrel as in this embodiment, positional deviation when fixed to the main base 116 is only that of one component, which is relatively less than the positional deviation of two components when fixed separately. This makes it possible to relatively stabilize optical performance.

[0030] Furthermore, the first and second optical systems are held by the main base 116, but as described above, they can move forward and backward together in the optical axis direction. If the lens barrel 100 is dropped or otherwise subjected to a strong impact, the first and second optical systems may move forward and backward in the optical axis direction while being supported by the guide barrel 102 and the cam barrel 103 inside the exterior of the lens barrel 100. In this case, the first barrel 111 may come into contact with a fixed component inside the exterior of the lens barrel 100, causing a very slight change in the mounting position of the first barrel 111 relative to the main base 116. Even in this case, if the lenses are held by a single barrel integrated with the left and right eyes as in this embodiment, the positional deviation when fixed to the main base 116 is only that of one component, which can be relatively reduced compared to the positional deviation of two components when fixed separately. This makes it possible to relatively stabilize optical performance.

[0031] First-group barrel 111 has diaphragm unit abutment portion 111d that extends in the optical axis direction. Electromagnetic diaphragm unit 115 is sandwiched between diaphragm unit abutment portion 111d of first-group barrel 111 and main base 116, and diaphragm unit abutment portion 111d abuts against electromagnetic diaphragm unit 115 to position electromagnetic diaphragm unit 115 in the optical axis direction. As with lens holding, when electromagnetic diaphragm unit 115 is fixed using an integrated lens barrel for the left and right eyes, holding accuracy can be improved by using only one part, compared to when separate lens barrels are used for the left and right eyes.

[0032] FIG. 3 is a horizontal cross-sectional view of the first lens barrel 111 of this embodiment. The left eye lens opening 111a and the right eye lens opening 111b are separated by a predetermined distance, the width of a base line length D. Due to the base line length D, images with parallax are captured by the first optical system for the left eye and the second optical system for the right eye, allowing the viewer to experience a three-dimensional effect. In general, increasing the lens diameter and increasing the amount of light is effective in improving the image quality of an optical system. However, in order to hold the lenses, a lens barrel holding portion 111e is required on the outer periphery of the lens group.

[0033] If the lens diameter d1a of the first group left lens L1a and the lens diameter d1b of the first group right lens L1b are increased while keeping the base line length D constant, the upper limit of the lens diameters will be restricted by the lens barrel holder 111e between the first group left lens L1a and the first group right lens L1b. If the lenses for each eye are held by separate lens barrels, the thick portion of the lens barrel holder 111e, equivalent to the thickness of two lens barrels, will be located in the central area where the first group left lens L1a and the first group right lens L1b are closest to each other.

[0034] In contrast, in this embodiment, the first group left lens L1a and the first group right lens L1b are held in a single lens barrel that is integrated for the left and right eyes. The first group left lens L1a and the first group right lens L1b are the lenses with the largest diameters in the first optical system and the second optical system, respectively. Therefore, the thickness (m1 in FIG. 3) of the portion between the first group left lens L1a and the first group right lens L1b can be made smaller than when they are held in separate lens barrels. Therefore, the lens barrel 100 of this embodiment can increase the lens diameter and improve optical performance under the condition that the base length D is constant in an optical design in which the optical axis is not bent.

[0035] Although the examples have been described with respect to interchangeable lenses, similar effects can be obtained when the lens barrel for recording images has a twin-lens configuration. Also, while the examples have been described with respect to a single-focus lens with a fixed focal length, the present invention can also be applied to a zoom lens with a variable focal length.

[0036] The present disclosure includes the following configurations. (Configuration 1) A lens barrel of a lens device having a first optical system and a second optical system arranged in parallel with an imaging element, each of which guides light to the imaging element, an integrally formed integral holding member that holds an eleventh lens group included in the first optical system and a twenty-first lens group included in the second optical system and corresponding to the eleventh lens group; a first holding member that holds a twelfth lens group included in the first optical system; a second holding member that is included in the second optical system and holds a 22nd lens group that corresponds to the 12th lens group; a lens barrel comprising a base barrel to which the integral holding member, the first holding member, and the second holding member are fixed; (Configuration 2) The lens barrel according to configuration 1, wherein the positions of the first holding member and the second holding member are adjustable relative to the base barrel. (Configuration 3) the integral holding member has a contact portion that contacts a light amount adjustment unit that adjusts the amount of light passing through each of the first optical system and the second optical system, The lens barrel according to configuration 1 or 2, wherein the integral holding member is fixed to the base barrel so as to sandwich the light amount adjustment unit between the integral holding member and the abutment portion in the optical axis direction. (Configuration 4) 4. The lens barrel according to any one of configurations 1 to 3, wherein the base barrel is movable in the optical axis direction. (Configuration 5) The lens barrel has a cam groove and a guide barrel has a linear groove extending in the optical axis direction. the base barrel has a cam follower that engages with the cam groove and the rectilinear groove, 5. The lens barrel according to configuration 4, wherein the cam barrel and the guide barrel rotate relatively around the optical axis, thereby moving the base barrel in the optical axis direction. (Configuration 6) 2. The lens barrel according to claim 1, wherein the position of the first holding member is adjustable relative to the second holding member. (Configuration 7) 7. The lens barrel according to configuration 6, wherein the first holding member is moved relative to the base barrel by a motor fixed to the base barrel. (Configuration 8) A lens device having the lens barrel according to any one of configurations 1 to 7. (Configuration 9) The lens device described in configuration 8, wherein the 11th lens group is a lens group including a lens with the largest diameter in the first optical system, and the 21st lens group is a lens group including a lens with the largest diameter in the second optical system. (Configuration 10) The lens device described in configuration 8 or 9, wherein the 11th lens group is the lens group arranged closest to the object in the first optical system, and the 21st lens group is the lens group arranged closest to the object in the second optical system. (Configuration 11) 8. An imaging device comprising: a lens device having the lens barrel according to any one of configurations 1 to 7; and an imaging element that captures an image formed by the lens device. [Explanation of symbols]

[0037] 100 Lens barrel 111 1st group lens barrel (integral holding member) 112a: Second group left barrel (first holding member) 112b Second group right barrel (second holding member) 113a 3rd group left barrel (first holding member) 113b 3rd group right barrel (second holding member) 114a 4th group left barrel (first holding member) 114b 4th group right barrel (second holding member) 116 Main base (base tube) 202 Image sensor L1a: Left lens in the first group (11th lens group) L1b 1st lens group right (21st lens group) L2a: Second lens group, left (12th lens group) L2b 2nd lens group right (22nd lens group) L3a: 3rd lens group (12th lens group) L3b 3rd lens group right (22nd lens group) L4a 4th lens group (12th lens group) L4b 4th lens group right (22nd lens group)

Claims

1. A lens barrel of a lens device having a first optical system and a second optical system arranged in parallel with an image sensor, each of which guides light to the image sensor, an integrally formed integral holding member that holds an eleventh lens group included in the first optical system and a twenty-first lens group included in the second optical system and corresponding to the eleventh lens group; a first holding member that holds a twelfth lens group included in the first optical system; a second holding member that is included in the second optical system and holds a 22nd lens group that corresponds to the 12th lens group; a base barrel to which the integral holding member, the first holding member, and the second holding member are fixed;

2. 2. The lens barrel according to claim 1, wherein the positions of the first barrel and the second barrel are adjustable relative to the base barrel.

3. the integral holding member has an abutment portion that abuts against a light amount adjustment unit that adjusts the amount of light passing through each of the first optical system and the second optical system, The lens barrel according to claim 1 , wherein the integral holding member is fixed to the base barrel so as to sandwich the light amount adjustment unit between the integral holding member and the abutment portion in the optical axis direction.

4. 2. The lens barrel according to claim 1, wherein the base barrel is movable in the optical axis direction.

5. The lens barrel has a cam groove and a guide barrel has a linear groove extending in the optical axis direction. the base barrel has a cam follower that engages with the cam groove and the rectilinear groove, 5. The lens barrel according to claim 4, wherein the cam barrel and the guide barrel rotate relatively around the optical axis, thereby causing the base barrel to move in the optical axis direction.

6. 2. The lens barrel according to claim 1, wherein the position of the first holding member is adjustable relative to the second holding member.

7. 7. The lens barrel according to claim 6, wherein the first holding member is moved relative to the base barrel by a motor fixed to the base barrel.

8. A lens device comprising the lens barrel according to any one of claims 1 to 7.

9. 9. The lens device according to claim 8, wherein the eleventh lens group is a lens group including a lens with a largest diameter in the first optical system, and the twenty-first lens group is a lens group including a lens with a largest diameter in the second optical system.

10. 9. The lens device according to claim 8, wherein the 11th lens group is the lens group arranged closest to the object in the first optical system, and the 21st lens group is the lens group arranged closest to the object in the second optical system.

11. 8. An imaging device comprising: a lens device having the lens barrel according to claim 1; and an imaging element for capturing an image formed by the lens device.

Images