Lens barrel, lens apparatus, and image pickup apparatus

Abstract

The present invention relates to a lens barrel having a first optical system and a second optical system which are arranged in parallel with respect to an image pickup element and guide light to the image pickup element, the lens barrel comprising: an integrated holding member, a holder integrally formed to hold an 11 lens unit included in the first optical system and a 21 lens unit included in the second optical system and corresponding to the 11 lens unit; a first holding member that holds the 12-lens unit included in the first optical system; a second holding member holding a 22 lens unit included in the second optical system and corresponding to the 12 lens unit; and a base lens barrel to which the integrated holding member, the first holding member, and the second holding member are fixed. The invention also relates to a lens apparatus and an image pickup apparatus.

Description

Technical Field

[0001] The present disclosure relates to a lens barrel, a lens apparatus, and an image pickup apparatus. Background Art

[0002] There is known a technique for performing stereoscopic imaging by an image pickup apparatus in which two optical systems are arranged in a horizontal direction. Japanese Patent Application Laid-Open No. H08-242468 discloses a technique for performing focus control on a pair of left and right lens barrels.

[0003] Japanese Patent Application Laid-Open No. H08-242468 discloses a technology in which, in an image pickup apparatus using a first lens barrel for the right eye and a second lens barrel for the left eye, focus information of the first lens barrel is calculated and focus adjustment is performed on the second lens barrel based on the calculated focus information.

[0004] When a viewer views the image formed on the image sensor by the first optical system of the first lens barrel and the image formed on the image sensor by the second optical system of the second lens barrel with their right and left eyes, respectively, the corresponding images are fused and can be recognized as a stereoscopic image. However, if the difference in the relative position between each lens unit and the image pickup element becomes larger due to manufacturing errors caused by the dimensions of the components constituting each lens barrel or the assembly of these components, the viewer is likely to perceive a difference in image quality between the right eye image and the left eye image. When the image quality difference is large, it is difficult for the viewer to fuse the left and right eye images, and the fatigue felt by the viewer while viewing may increase.

[0005] Furthermore, given the width (base length) of the left and right eyes, the thickness of the lens holding barrel at the closest point between the first and second optical systems is a limitation in increasing the diameter of the lens to improve optical performance. Summary of the Invention

[0006] A lens barrel according to the present disclosure is a lens barrel having a first optical system and a second optical system which are arranged parallel to an image pickup element and guide light to the image pickup element, wherein the optical system includes: an integral retaining member which is integrally formed to retain an eleventh lens unit included in the first optical system and a twenty-first lens unit corresponding to the eleventh lens unit included in the second optical system; a first retaining member which retains a twelfth lens unit included in the first optical system; a second retaining member which retains the twenty-second lens unit corresponding to the twelfth lens unit included in the second optical system; and a base barrel to which the integral retaining member, the first retaining member, and the second retaining member are fixed.

[0007] Further features of the present disclosure will become apparent from the following description of exemplary embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 is a cross-sectional view of an interchangeable lens including a lens barrel and a camera body for a single-lens reflex camera according to an embodiment.

[0009] Figure 2 is a perspective view of the first-unit lens barrel 111 according to the embodiment.

[0010] Figure 3 is a horizontal cross-sectional view of the first-unit lens barrel 111 according to the embodiment. DETAILED DESCRIPTION

[0011] Hereinafter, a lens barrel 100 , a lens apparatus, and an image pickup apparatus according to an embodiment of the present disclosure will be described in detail with reference to the accompanying drawings.

[0012] The present disclosure relates to a lens barrel, a lens device, and an image pickup device that are capable of performing stereoscopic photography by moving at least a portion of a first optical system and a second optical system in an optical axis direction to perform zoom or focus adjustment, wherein the first optical system and the second optical system are arranged parallel to an image pickup element and guide light to the image pickup element.

[0013] [Example]

[0014] The lens barrel 100 according to an embodiment of the present disclosure will be described.

[0015] Figure 1 is a sectional view of an image pickup apparatus including an interchangeable lens (lens apparatus) for a single-lens reflex camera, and an image pickup element 202 that picks up an image formed by the lens, the interchangeable lens including the lens barrel 100 according to an embodiment of the present disclosure.

[0016] Line Xa-Xa in the figure represents the optical axis of the first optical system that forms an image for the left eye. Line 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 description, elements related to the first optical system are represented by reference numeral a, and elements related to the second optical system are represented by reference numeral b.

[0017] The mount 101 provided in the lens barrel 100 is a component having a bayonet portion to be attached to the camera mount 201 provided in the camera body 200. The guide barrel 102 is integrally fixed to the mount 101 together with the outer cylindrical body 104. The cam barrel 103 is rotatably held on the outer periphery of the guide barrel 102 about the optical axis. The cam barrel 103 is connected to a stepping motor unit (not shown) held at the image side end of the guide barrel 102 via gears. The cam barrel 103 is configured to rotate when the stepping motor unit rotates according to control information from the control board 108.

[0018] The 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 the shutter button provided in the camera body 200 is operated, the image pickup element 202 is controlled by the camera control circuit 203 so as to capture the image formed on the image pickup element 202 by the first and second optical systems. Since the first and second optical systems are arranged parallel to the image pickup element 202, two image circles are formed in parallel on the image pickup element 202. A charge coupled device (CCD), a CMOS (complementary metal oxide semiconductor), or the like is used as the image pickup element 202.

[0019] The first and second optical systems are optically composed of identical lens units and are positioned with a constant interval (baseline length) between them in the left-right direction. The frontmost cover glass 107, held by a filter frame 106 screwed to the guide barrel 102, serves to protect the interior 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 positioned on the image side of the cover glass 107.

[0020] The first optical system includes, in order from the object side to the image side, a first left lens unit (11 lens units) L1a, a second left lens unit (12 lens units) L2a, a third left lens unit (12 lens units) L3a, and a fourth left lens unit (12 lens units) L4a. The second optical system includes, in order from the object side to the image side, a first right lens unit (21 lens units) L1b, a second right lens unit (22 lens units) L2b, a third right lens unit (22 lens units) L3b, and a fourth right lens unit (22 lens units) L4b.

[0021] Optically, the first-unit left lens L1a corresponds to the first-unit right lens L1b, the second-unit left lens L2a corresponds to the second-unit right lens L2b, the third-unit left lens L3a corresponds to the third-unit right lens L3b, and the fourth-unit left lens L4a corresponds to the fourth-unit right lens L4b.

[0022] The first-unit left lens L1a of the first optical system and the first-unit right lens L1b of the second optical system are both lens units disposed closest to the object side and are held by a first-unit lens barrel (integrated holding member) 111, which serves as a lens holding frame formed of one integral member. The first-unit lens barrel 111 is fixed to a main base (base lens barrel) 116 in the optical axis direction by screws.

[0023] The second unit left lens (12 lens unit) L2a is held by the second unit left lens barrel (first holding member) 112a. The second unit right lens (22 lens unit) L2b is held by the second unit right lens barrel (second holding member) 112b. Three second unit eccentric rollers 112c are fixed to each of the second unit left lens barrel 112a and the second unit right lens barrel 112b by screws at intervals of approximately 120 degrees in the circumferential direction of the lens barrel 100. The second unit eccentric roller 112c has a cylindrical portion that is eccentric with respect to the central axis of the screw fixed to the second unit left lens barrel 112a or the second unit right lens barrel 112b. The cylindrical portion engages with the second unit eccentric roller engagement groove 111c (see Figure 3 By rotating the second-unit eccentric roller 112c around the axis of the screw, the axial position relative to the second-unit eccentric roller engagement groove 111c changes in a plane whose normal line is perpendicular to the optical axis.

[0024] Therefore, the relative positions of the second-unit left lens barrel 112a and the second-unit right lens barrel 112b with respect to the first-unit lens barrel 111 can be changed. Therefore, the positions of the second-unit left lens L2a and the second-unit right lens L2b in the optical axis direction, the decentering direction, and the tilt direction can be changed relative to the first-unit left lens L1a and the first-unit right lens L1b held by the first-unit lens barrel 111. As a result, optical adjustment can be performed for correcting positional deviation in the optical axis direction and optical axis deviation occurring in the lens units due to manufacturing errors.

[0025] The fourth-unit left lens (12-unit lens unit) L4a is held by the fourth-unit left lens barrel (first holding member) 114a. The fourth-unit right lens (22-unit lens unit) L4b is held by the fourth-unit right lens barrel (second holding member) 114b. Three fourth-unit eccentric rollers 114c are fixed to each of the fourth-unit left lens barrel 114a and the fourth-unit right lens barrel 114b with screws at intervals of approximately 120 degrees in the circumferential direction. The fourth-unit eccentric rollers 114c have cylindrical portions that are eccentric relative to the central axis of the screws securing the fourth-unit left lens barrel 114a or the fourth-unit right lens barrel 114b. The cylindrical portions engage with fourth-unit eccentric roller engagement grooves 116c provided in the main base 116. By rotating the fourth-unit eccentric rollers 114c about the axis of the screws, the axial position relative to the fourth-unit eccentric roller engagement grooves 116c changes in a plane whose normal is perpendicular to the optical axis.

[0026] Therefore, the relative positions of the fourth-unit left lens barrel 114a and the fourth-unit right lens barrel 114b with respect to the first-unit lens barrel 111 fixed to the main base 116 can be changed. Therefore, the positions of the fourth-unit left lens L4a and the fourth-unit right lens L4b in the optical axis direction, the decentering direction, and the tilt direction can be changed with respect to the first-unit left lens L1a and the first-unit right lens L1b held by the first-unit lens barrel 111. As a result, optical adjustment can be performed for correcting positional deviation in the optical axis direction or optical axis deviation occurring in the lens units due to manufacturing errors.

[0027] The third-unit left lens (12-lens unit) L3a is held by the third-unit left lens barrel (first holding member) 113a. The third-unit left lens barrel 113a is fixed to the main base 116 by screws. The third-unit right lens (22-lens unit) L3b is held by the third-unit right lens barrel (second holding member 113b). The third-unit right lens barrel 113b is supported movably in the optical axis direction by two guide rods (not shown) extending in the optical axis direction. The two guide rods are held by the first-unit lens barrel 111 and the main base 116.

[0028] A stepping motor 119 having a lead screw is fixed to the main base 116 by screws. A rack (not shown) engaged with the lead screw of the stepping motor 119 is held by the third-unit right lens 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-unit right lens barrel 113b moves back and forth in the optical axis direction relative to the main base 116.

[0029] The electromagnetic aperture stop unit (light quantity adjustment unit) 115 is held by the first-unit lens barrel 111 and the main base 116. The electromagnetic aperture stop unit 115 has a first opening through which the light beam of the first optical system passes and a second opening through which the light beam of the second optical system passes, and a plurality of aperture blades are provided within each of the first and second openings. The plurality of aperture blades of the first and second openings are driven by an aperture stop drive motor controlled by the control board 108, and the amount of light reaching the image pickup element 202 is adjusted by changing the area of the openings.

[0030] An image is formed on the image pickup element 202 by the first optical system and the second optical system. Manufacturing errors such as dimensional deviations of each component from the design value or deviations in the attachment position during assembly may cause the optical performance of the image obtained on the image pickup element 202 to degrade. By optically adjusting the second-unit left lens L2a and the second-unit right lens L2b using the second-unit eccentric roller 112c, and optically adjusting the fourth-unit left lens L4a and the fourth-unit right lens L4b using the fourth-unit eccentric roller 114c, the optical performance can be brought close to the design value. When there is a focus difference between the left and right eye images due to factors such as relative positional deviations of the first and second optical systems and tilt relative to the image pickup element 202, they can be adjusted by moving the third-unit right lens L3b back and forth in the optical axis direction by the stepping motor 119.

[0031] The main base 116 is provided with cam followers 116d at intervals of approximately 120 degrees in the circumferential direction. The cam followers 116d engage with a linear groove 102c extending in the optical axis direction provided in the guide barrel 102 and a cam groove 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 described above, since the corresponding lens units of the first optical system and the second optical system are retained in the main base 116, the corresponding lens units of the first optical system and the second optical system can be moved integrally in the optical axis direction relative to the image pickup element 202 by the advancement and retreat of the cam followers 116d.

[0032] When a control signal is sent to the gear unit and the cam ring rotates based on focus information obtained by processing an image captured by the image pickup element 202 by the camera control circuit 203, the cam follower 116d moves back and forth in the optical axis direction to perform a focusing operation. Alternatively, when the photographer rotates the focus operation ring 105 about the optical axis, a control signal is sent from the control board 108 to the gear unit based on the amount of rotation detected by a focus operation ring rotation sensor (not shown), causing the cam barrel 103 to rotate. This operation similarly allows the cam follower 116d to move back and forth to perform a focusing operation.

[0033] Although the stepping motor 119 with a lead screw is used to drive the third unit right lens barrel 113b and the stepping motor unit coupled to the gear is used to rotate the cam barrel 103, the configuration of the present disclosure is not limited thereto. For example, a DC motor or an ultrasonic motor may be used for driving.

[0034] Figure 2 : is a stereoscopic diagram of the first unit lens barrel 111 of the present embodiment. The first unit lens barrel 111 holds the first unit left lens L1a and the first unit right lens L1b. By holding the first unit left lens L1a and the first unit right lens L1b by one component in this manner, the positional deviation of the lens relative to the image pickup element 202 can be suppressed compared to the case where each lens is held by a separate lens barrel. In the case where each lens is held by a separate lens barrel, in addition to the component size deviation of the lens barrel, relative positional deviation will also occur when the lens barrel is fixed to the main base 116. However, if the holding is performed by one lens barrel that is integrated with the left and right eyes as in the present embodiment, the positional deviation that occurs when fixed to the main base 116 is to the extent caused by only one component, and the positional deviation can be relatively reduced compared to the case where the two components are fixed separately. Therefore, the optical performance can be relatively stabilized.

[0035] Although the first optical system and the second optical system are held by the main base 116, they can be moved integrally in the optical axis direction as described above. If a strong impact is applied to the lens barrel 100 due to falling or the like, the first optical system and the second optical system may move back and forth in the optical axis direction while being supported by the guide barrel 102 and the cam barrel 103 on the inner side of the outer portion of the lens barrel 100. In this case, since the first unit lens barrel 111 abuts against the fixed component on the inner side of the outer portion of the lens barrel 100, the attachment position of the first unit lens barrel 111 relative to the main base 116 may change slightly. Also in this case, if the lens is held by one lens barrel that is integrated with the left and right eyes as in the present embodiment, the positional deviation that occurs when it is fixed to the main base 116 is to the extent caused by only one component, and the positional deviation can be relatively reduced compared to the case where the two components are fixed separately. Therefore, the optical performance can be relatively stabilized.

[0036] The first-unit lens barrel 111 has an aperture stop unit contact portion 111 d extending in the optical axis direction. The electromagnetic aperture stop unit 115 is clamped between the aperture stop unit contact portion 111 d of the first-unit lens barrel 111 and the main base 116, and the aperture stop unit contact portion 111 d contacts the electromagnetic aperture stop unit 115 to position the electromagnetic aperture stop unit 115 in the optical axis direction. Regarding the fixing of the electromagnetic aperture stop unit 115 in the same manner as the lens holder, when holding it with a lens barrel provided for the left eye and the right eye separately, the holding accuracy can be improved by using only a single component.

[0037] Figure 3 : is a horizontal cross-sectional view of the first unit lens barrel 111 of this embodiment. The left-eye lens opening 111a and the right-eye lens opening 111b are separated from each other by a baseline length D, which is a predetermined distance. Since the first optical system for the left eye and the second optical system for the right eye capture images with parallax via this baseline length D, the viewer can obtain a stereoscopic effect. Generally speaking, in order to improve the image quality of the optical system, it is effective to increase the lens diameter to increase the amount of light. However, in order to hold the lenses, a lens barrel holding portion 111e is required on the periphery of the lens unit.

[0038] When the lens diameter d1a of the first-unit left lens L1a and the lens diameter d1b of the first-unit right lens L1b increase under the condition that the baseline length D is constant, the lens barrel holding portion 111e between the first-unit left lens L1a and the first-unit right lens L1b becomes a constraint on the upper limit of the lens diameter. In the case where the lenses for the left eye and the right eye are held by separate lens barrels, the thick portion of the lens barrel holding portion 111e for the two lens barrels is located at the center portion, which is the closest position between the first-unit left lens L1a and the first-unit right lens L1b.

[0039] On the other hand, in this embodiment, the first-unit left lens L1a and the first-unit right lens L1b are held by a single lens barrel integrated with the left and right eyes. The first-unit left lens L1a and the first-unit right lens L1b are the lenses with the largest diameters in the first optical system and the second optical system, respectively. Therefore, the thickness of the portion between the first-unit left lens L1a and the first-unit right lens L1b can be reduced compared to a case where the lenses are held by separate lens barrels ( Figure 3 Therefore, under the condition that the baseline length D is constant in an optical design without bending the optical axis, the lens barrel 100 of this embodiment can improve the optical performance by increasing the lens diameter.

[0040] Although the embodiment has been described for an interchangeable lens, the same effect can be obtained when the lens barrel for recording images has a dual-lens structure. In addition, although the embodiment has been described for a single-focal-length lens with a fixed focal length, the present disclosure is also applicable to a zoom lens with a variable focal length.

[0041] Although the embodiments of the present disclosure have been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims

1. A lens barrel having a first optical system and a second optical system arranged in parallel with an image pickup element and guiding light to the image pickup element, the lens barrel comprising: an integral holding member integrally formed to hold 11 lens units included in the first optical system and 21 lens units included in the second optical system and corresponding to the 11 lens units; a first holding member that holds 12 lens units included in the first optical system; a second holding member that holds 22 lens units included in the second optical system and corresponding to the 12 lens units; and A base lens barrel to which the integrated holding member, the first holding member, and the second holding member are fixed.

2. The lens barrel according to claim 1, wherein: The positions of the first lens barrel and the second lens barrel can be adjusted relative to the base lens barrel.

3. The lens barrel according to claim 1, in, The integrated holding member includes a contact portion that contacts a light quantity adjustment unit configured to adjust a light quantity of a light beam passing through each of the first optical system and the second optical system, and The integrated holding member is fixed to the base lens barrel so as to sandwich the light quantity adjustment unit between the integrated holding member and the contact portion in the optical axis direction.

4. The lens barrel according to claim 1, wherein The base lens barrel can move in the optical axis direction.

5. The lens barrel according to claim 1 , further comprising: a cam barrel having a cam groove; and a guide cylinder having a linear groove extending in the optical axis direction, wherein the base lens barrel has a cam follower engaged with the cam groove and the linear groove, The cam barrel and the guide barrel rotate relative to each other around the optical axis to move the base lens barrel in the optical axis direction. The lens barrel according to claim 1 , wherein: The position of the first retaining member is adjustable relative to the second retaining member.

7. The lens barrel according to claim 6, wherein: The first holding member is moved relative to the base lens barrel by a motor fixed to the base lens barrel. 8 . A lens device comprising the lens barrel according to claim 1 .

9. The lens apparatus according to claim 8, wherein The 11-lens unit is a lens unit including a lens having the largest diameter in the first optical system, and the 21-lens unit is a lens unit including a lens having the largest diameter in the second optical system.

10. The lens apparatus according to claim 8, wherein The 11-lens unit is a lens unit disposed closest to the object in the first optical system, and the 21-lens unit is a lens unit disposed closest to the object in the second optical system.

11. An image pickup device comprising: A lens apparatus having the lens barrel according to any one of claims 1 to 7; and an image pickup element for picking up an image formed by the lens apparatus.

Images