Patent ID: 12253795

DESCRIPTION OF THE EMBODIMENTS

Referring now to the accompanying drawings, a detailed description will be given of embodiments according to the present invention.

A lens apparatus (interchangeable lens) according to this embodiment has two optical systems (such as a first optical system and a second optical system) arranged in parallel (symmetrically), and is configured so that two image circles are formed in parallel on a single image sensor. The two optical systems are arranged in the horizontal direction and spaced by a predetermined distance (baseline length). When viewed from the image side, the image formed by the right optical system (first optical system) is recorded as a motion image or still image for the right eye, and the image formed by the left optical system (second optical system) is recorded as a motion image or still image for the left eye. In reproducing a motion image or a still image (video), viewing with a known 3D display or so-called VR goggles, the viewer's right eye views the right-eye image and his left eye views the left-eye image. At this time, images with a parallax are projected on the right eye and the left eye according to the baseline length of the lens apparatus, so that the viewer can obtain a stereoscopic effect. Thus, the lens apparatus according to this embodiment is a lens apparatus for stereoscopic photography capable of forming two images with a parallax through the first and second optical systems.

Referring now toFIGS.1to4, a description will be given of a configuration of a lens apparatus (interchangeable lens)200according to this embodiment.FIG.1is a sectional view of the lens apparatus200and illustrates schematic configurations of a right-eye optical system201R and a left-eye optical system201L in the lens apparatus200.FIG.2is an exploded perspective view of one (single-eye) optical system among the right-eye optical system201R and the left-eye optical system201L.FIG.3is an exploded perspective view of the lens apparatus200as viewed from the object side.FIG.4is an exploded perspective view of the lens apparatus200viewed from the image side. In the following description, the right-eye optical system will be suffixed with R, and the left-eye optical system will be suffixed with L. The description common to both the right-eye and left-eye optical systems do not include R or L at the end of the reference numeral.

The lens apparatus200includes the right-eye optical system (first optical system)201R and the left-eye optical system (second optical system)201L. The right-eye optical system201R and the left-eye optical system201L are two optical systems arranged in parallel (symmetrically). The right-eye optical system201R and the left-eye optical system201L have, in order from the object side to the image side, first optical axes OA1R and OA1L, second optical axes OA2R and OA2L approximately orthogonal to the first optical axes, and third optical axes OA3R and OA3L approximately parallel to the first optical axes. Here, the term “approximately orthogonal or approximately parallel” is meant to include not only a strictly orthogonal or parallel configuration but also a configuration that is evaluated to be substantially orthogonal or parallel.

The right-eye optical system201R and the left-eye optical system201L include first-unit lenses (first lenses)210R and210L, second-unit lenses (second lenses)220R and220L, and third-unit lenses (third lenses)230R and230L along the optical axes. The first-unit lenses210R and210L are disposed on the first optical axes OA1R and OA1L, the second-unit lenses220R and220L are disposed on the second optical axes OA2R and OA2L, and the third-unit lenses230R and230L are the third optical axes OA3R and OA3L.

The right-eye optical system201R and the left-eye optical system201L have first prisms (first reflective surfaces)211R and211L and second prisms (second reflective surfaces)221R and221L, respectively. The first prisms211R and211L bend light fluxes of the first optical axes OA1R and OA1L toward those of the second optical axes OA2R and OA2L, respectively. The second prisms221R and221L bend light fluxes of the second optical axes OA2R and OA2L toward those of the third optical axes OA3R and OA3L. Thus, the right-eye optical system201R and the left-eye optical system201L are bending optical systems. The first prisms211R and211L reflect and bend the light fluxes of the first optical axes OA1R and OA1L toward those of the second optical axes OA2R and OA2L. The second prisms221R and221L reflect and bend the light fluxes of the second optical axes OA2R and OA2L toward those of the third optical axes OA3R and OA3L.

The right-eye optical system201R and the left-eye optical system201L have first-unit lens holders212R and212L, second-unit lens holders222R and222L, and third-unit lens holders231R and231L, respectively. The first-unit lens holders212R and212L hold the first-unit lenses210R and210L and the first prisms211R and211L, respectively. The second-unit lens holders222R and222L hold the second-unit lenses220R and220L and the second prisms221R and221L, respectively. The third-unit lens holders231R and231L hold third-unit lenses230R and230L, respectively.

The right-eye optical system201R and the left-eye optical system201L are fixed to a lens base (lens support member)203, respectively. The lens base203is fixed to a lens mount202for connecting the lens apparatus200to the camera body110. In this embodiment, outer circumferential parts231aR and231aL of the third-unit lens holders231R and231L are engaged with circumferential surfaces203aR and203aL of the lens base203around the third optical axes OA3R and OA3L as the centers. The second-unit lens holders222R and222L of the right-eye optical system201R and the left-eye optical system201L are connected to each other via connectors222aR and222aL provided to the second-unit lens holders222R and222L, respectively.

Reference numeral L1denotes a distance between the first optical axis OA1R of the right-eye optical system201R and the first optical axis OA1L of the left-eye optical system201L, or a baseline length. The longer the baseline length L1becomes, the stronger the stereoscopic effect becomes in viewing an image. Reference numeral L2denotes a distance between the third optical axis OA3R of the right-eye optical system201R and the third optical axis OA3L of the left-eye optical system201L. φD denotes a diameter (aperture or mount diameter) of the lens mount202that can be attached to the camera body, and corresponds to an engagement diameter between the lens mount202and a camera mount122. Reference numeral202F denotes a flange surface of the lens mount202.

As illustrated inFIG.2, each of the right-eye optical system201R and the left-eye optical system201L has a first-unit lens holder212that holds the first-unit lens210. The first-unit lens holder212is fixed by a press ring215and covered with a dustproof member216for preventing dust from entering from top of the press ring215. The first-unit lens210is attached to a first-unit lens base213via two types of three rollers214aand two rollers214bso that tilt decentering of the first-unit lens holder212can be optically adjusted.

The first prism211is attached and adhered to a prism base217from a direction along the second optical axis OA2. A prism mask224is attached to the prism surface of the first prism211to block light rays outside the optical path. The prism base217and the first-unit lens base213are fixed with unillustrated screws. The second-unit lens220is attached and adhered to the second-unit lens holder222from the direction along the second optical axis OA2. The second prism221is attached and adhered to the second-unit lens holder222from the direction along the third optical axis OA3. A prism mask233is pasted onto the prism surface of the second prism221to shield light rays outside the optical path.

A diaphragm (aperture stop) unit223is disposed between the second-unit lens holder222and the prism base217. The prism base217is screwed and fixed onto the second-unit lens holder222. The third-unit lens230is held by the third-unit lens holder231, and is screwed and fixed onto the second-unit lens holder222.

As illustrated inFIGS.3and4, the right-eye optical system201R and the left-eye optical system201L are screwed and fixed onto the lens base203. Two types of spacers209aand209band a washer218are sandwiched between each of the two optical systems or the right-eye optical system201R and the left-eye optical system201L, and the lens base203. Adjusting the thickness of each of the spacers209aand209band the washer218can suppress the focus fluctuations caused by the manufacturing errors of the two left and right optical systems so that the two optical systems can have the same focus positions.

FIG.7schematically illustrates a focusing unit in the image pickup apparatus100. As illustrated inFIG.7, the lens base203is fixed to the lens mount202for mounting on the camera mount122of the camera body110, via a focus flange204and a focus ring (operation member)205. The focus ring205is a member whose thickness changes like a cam depending on an angle of rotation. Rotating the focus ring205can change a distance between the focus flange204and the lens base203.

In this way, the focus ring205is formed with a cam shape having a different thickness depending on a rotation phase. The right-eye optical system201R and the left-eye optical system201L are fixed to the lens base203, and when the focus ring205is operated, the lens base203moves back and forth. In other words, since the cam shape of the focus ring205is sandwiched between the lens base203and the lens mount202, the lens base203moves back and forth as the focus ring205is rotated.

This configuration can entirely project or retract the entire right-eye optical system201R and left-eye optical system201L of the lens apparatus200can be extended or retracted. In other words, operating the focus ring205provides focusing of both the right-eye optical system201R and the left-eye optical system201L. Thereby, focusing can be made, and the right-eye optical system201R and the left-eye optical system201L can be focused at the same time. The right-eye optical system201R and the left-eye optical system201L are independently focusable.

In the first-unit lens210in the lens apparatus200according to this embodiment, a diameter of a lens closer to the object is larger, so that the size in the width direction of the lens apparatus200also spreads toward the object side in a trumpet shape. Hence, when the focus ring205is located outside the first-unit lens of the left and right optical systems, the diameter of the focus ring205becomes large. If the outer diameter of the focus ring205projects from the bottom surface of the camera, an attachment to a tripod may become difficult. When the optical system has a wide-angle lens such as a fisheye lens and the focus ring205is disposed closer to the object of the lens apparatus200, the hand operating the focus ring205may be reflected within the angle of view. On the other hand, the large diameter of the focus ring205is advantageous in improving the operational feeling because the operation torque is easily transmitted and in facilitating fine adjustments.

Accordingly, the lens apparatus200according to this embodiment disposes the focus ring205on the image plane side of the reflective surface of the first prism211so that it overlaps the reflective surfaces of the first prisms211R and211L when viewed along the first optical axis. The focus ring205is rotatably disposed coaxially with the lens mount202. The third-unit lenses230R and230L are located inside the inner diameter of the focus ring205. This embodiment disposes the focus ring205at a position overlapping the first prisms211R and211L when viewed along the first optical axis. As a result, the focus ring205can be made smaller than the focus ring205disposed near the first-unit lenses210R and210L, and the outer diameter of the focus ring205is prevented from protruding from the bottom surface of the camera body (or it does not protrude from the bottom surface of the camera body). The focus ring205coaxial with the lens mount202and the lens of the third optical axis located inside the inner diameter of the focus ring205can secure the operational feeling equivalent to that of the conventional single interchangeable lens.

The focus ring205is not limited to the focusing function (operation member for focusing), but may be replaced with an operation ring having another function, such as a zoom ring (operation member for adjusting an angle of view) and a diaphragm ring (operation member for adjusting an F-number). In that case, the lens base203is directly fixed to the focus flange204and the lens mount202without intervening the focus ring205.

The third-unit lenses230R and230L disposed on the third optical axis OA3are also disposed so as to enter the inside of the flange surface of the camera mount122which is attached across the flange surface202F of the lens mount202. In particular, when the lens apparatus200according to this embodiment is used for a mirrorless camera as the camera body110, unlike a single-lens reflex camera, an optical refraction member such as a mirror or a mirror-up operation space is not required. Thus, it is possible to design the lens apparatus200so that the lens apparatus200largely enters the inside of the camera body110rather than the flange surface.

Referring now toFIG.5, a description will be given of a positional relationship among the position of each optical axis in the lens apparatus200, the lens mount unit202, and the image circle on the image sensor111in the camera body110.FIG.5illustrates a positional relationship between the lens apparatus200and the image circle.

On the image sensor111of the camera body110, two image circles or a right-eye image circle ICR formed by the right-eye optical system201R and a left-eye image circle ICL formed by the left-eye optical system201L form images in parallel. The sizes of the image circles and the distance between them may be set so that the two image circles do not overlap each other. For example, assume a light-receiving area of the image sensor111is divided into left and right halves at the center, and the center of the right-eye image circle ICR may be located at the approximately center of the right area of the light-receiving area and the center of the left-eye image circle ICL may be located at the approximately center of the left area of the light-receiving area, respectively. The optical system (the right-eye optical system201R and the left-eye optical system201L) according to this embodiment is an all-round fish-eye lens (wide-angle fisheye lens), and the image captured on the imaging surface is a circular image made by imaging a range with an angle of view of about 180°, and two circular images are formed on the left and right, respectively.

Referring now toFIG.6, a description will be given of the configuration of the image pickup apparatus according to this embodiment.FIG.6schematically illustrates the image pickup apparatus100. The image pickup apparatus100can capture a stereoscopic image. The image pickup apparatus100includes the camera body110and the lens apparatus200. The lens apparatus200is an interchangeable lens that can be attached to and detached from the camera body110. However, the present invention is not limited to this embodiment, and is applicable to an image pickup apparatus in which the camera body110and the lens apparatus200are integrated with each other.

The lens apparatus200includes the right-eye optical system201R, the left-eye optical system201L, and a system controller (lens system controller)227. The camera body110includes the image sensor111, an A/D converter112, an image processor113, a display unit114, an operation unit115, a memory116, a system controller (camera system controller)117, and the camera mount122. When the lens apparatus200is mounted on the camera mount122of the camera body110via the lens mount202, the system controller117of the camera body110and the system controller227of the lens apparatus200are electrically connected to each other.

The image of the object is captured on the image sensor111which includes the right-eye image (first image) formed through the right-eye optical system201R and the left-eye image (second image) formed through the left-eye optical system201L, which are arranged in parallel. The image sensor111converts the captured image (optical signal) of the object into an analog electric signal. The A/D converter112converts the analog electric signal output from the image sensor111into a digital electric signal (image signal). The image processor113performs various image processing for the digital electric signal (image signal) output from the A/D converter112.

The display unit114displays various information. The display unit114is implemented, for example, by using an electronic viewfinder and a liquid crystal panel. The operation unit115serves as a user interface used for a user giving an instruction to the image pickup apparatus100. When the display unit114has a touch panel, the touch panel also constitutes one of the operation units115. The memory116stores various data such as image data that has undergone image processing by the image processor113. The memory116also stores a computer program. The memory116is implemented, for example, by using a ROM, a RAM, and an HDD. The system controller117centrally controls the entire image pickup apparatus100. The system controller117is implemented, for example, by using a CPU.

For example, assume that the image sensor111has a size (sensor size) of 24 mm in length×36 mm in width, the image circle has a diameter of φ17 mm, a distance between the left and right third optical axes OA3is 18 mm, and the left and right second optical axes OA2are as long as 21 mm. When the right-eye optical system201R and the left-eye optical system201L are arranged so that the second optical axes OA2extend in the horizontal direction, the baseline length L1becomes 60 mm, which is approximately equal to the eye width of an adult. The diameter ΦD of the lens mount202can be made shorter than the baseline length L1. Making the distance L2between the left and right third optical axes OA3shorter than the diameter ΦD of the lens mount202can arrange the third-unit lenses230R and230L on the third optical axis OA3inside (on the inner circumference of) the lens mount202.

Thus, in this embodiment, the distance (baseline length L1) between the first optical axes OA1R and OA1L in the two optical systems is longer than the diameter φD of the lens mount202, and the distance L2between the third optical axes OA3R and OA3L in the two optical systems is shorter than the diameter φD of the lens mount202. In each of the two optical systems, all the third lenses (third-unit lens230) may be disposed within the range of the diameter of the lens mount. In each of the two optical systems, at least part of the third lens may be disposed closer to the image plane than the flange surface202F of the lens mount. In each of the two optical systems, the second optical axis may be disposed closer to the object than the flange surface202F of the lens mount.

This embodiment can provide a compact lens apparatus and image pickup apparatus, each of which can properly set a baseline length and obtain a natural stereoscopic effect.

While the present invention has 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.

This application claims the benefit of Japanese Patent Application Nos. 2019-170173, filed on Sep. 19, 2019, and 2020-103751, filed on Jun. 16, 2020, each of which is hereby incorporated by reference herein in its entirety.