Lens barrel and photographing apparatus including the same

A lens barrel and a photographing apparatus including the lens barrel include a clutch assembly disposed on a plane orthogonal to an optical axis between a manual adjustment ring and a distance adjustment ring. The clutch assembly rotates on a fixing part of the lens barrel and includes first, second, and third clutch wheels and one or more rollers, wherein the first clutch wheel includes an operator disposed on an end thereof and that receives a rotation force of the manual adjustment ring, the second clutch wheel is disposed on an inner surface of the first clutch wheel, the third clutch wheel is disposed on an inner surface of the second clutch wheel and fixed to the distance adjustment ring, and the rollers are radially disposed with respect to the optical axis and comprise surfaces contacting the operator and other surfaces contacting an outer surface of the third clutch wheel, wherein the first and second clutch wheels are elastically fixed to each other by first elastic members, a second elastic member is disposed between the second clutch wheel and the fixing part, and a third elastic member is disposed at both ends of the second clutch wheel, supports ends of circumferential surfaces of the rollers, and controls positions of the rollers.

CROSS-REFERENCE TO RELATED PATENT APPLICATION

This application claims the priority benefit of Korean Patent Application No. 10-2010-0009663, filed on Feb. 2, 2010, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.

BACKGROUND

1. Field of the Invention

Embodiments relate to a lens barrel and a photographing apparatus including the same, and more particularly, to a lens barrel including an optical system driven by a manual manipulation ring and a ring-shaped oscillating wave motor and a photographing apparatus including the same.

2. Description of the Related Art

A photographing apparatus is an apparatus which captures an image of a subject. Photographing apparatuses such as a digital still camera, a digital video camera, or the like have been distributed.

A photographing apparatus typically has an auto-focusing (AF) function of automatically adjusting a focus. However, high-class users and old-style seeking users mostly prefer photographing apparatuses having AF functions and manual-focusing (MF) functions. Therefore, photographing apparatuses having AF and MF functions have come onto the market.

In general, a conversion button is installed in a lens barrel of a photographing apparatus having AF and MF functions. Thus, if a user manipulates the conversion button, the AF function is converted into the MF function or the MF function is converted into the AF function.

SUMMARY

A full time manual mechanical driving apparatus, which performs an MF operation during an AF operation, solves an inconvenience of performing a conversion.

Embodiments include a lens barrel having an optical system driven by a manual manipulation ring and a ring-shaped oscillating wave motor and a photographing apparatus including the lens barrel.

According to an embodiment, a lens barrel transmits a rotation force of a ring-shaped oscillating wave motor or a manual adjustment ring to a distance adjustment ring for driving a lens, to move a position of a focus lens. The lens barrel includes: a manual adjustment ring; a ring-shaped oscillating wave motor; a distance adjustment ring; a fixing part; and a clutch assembly which is disposed on a plane orthogonal to an optical axis between the manual adjustment ring and the distance adjustment ring and that rotates on the fixing part of the lens barrel. The clutch assembly includes: a first clutch wheel that includes an operator disposed on an end thereof and receives a rotation force of the manual adjustment ring; a second clutch wheel disposed on an inner surface of the first clutch wheel; a third clutch wheel disposed on an inner surface of the second clutch wheel and fixed to the distance adjustment ring; at least one roller radially disposed with respect to the optical axis and comprising a surface contacting the operator of the first clutch wheel and another surface contacting an outer surface of the third clutch wheel; a plurality of first elastic members that elastically fix the first and second clutch wheels to each other; a second elastic member disposed between the second clutch wheel and the fixing part; and a third elastic member disposed at both ends of the second clutch wheel, that supports ends of circumferential surfaces of the rollers, and that controls positions of the rollers.

A pair of first elastic members may be disposed symmetrically with respect to the operator of the first clutch wheel.

The first elastic members may include first support parts which enclose a part of an outer surface of the first clutch wheel and second support parts which penetrate through the first and second clutch wheels, wherein a pair of first support parts and a pair of second support parts are disposed symmetrically with respect to the operator.

The second elastic member may reduce a rotation force of the second clutch wheel with respect to the fixing part.

The third elastic member may be a plate spring.

The third elastic member may be a compressive coil spring.

Torque of the second clutch wheel caused by the second elastic member may be greater than torque of the first clutch wheel caused by the first elastic members.

The operator may have a shape having four sides which face one another.

The ring-shaped oscillating wave motor may include a motor stator which generates an oscillating wave, a motor rotor which frictionally contacts the motor stator and rotates on the optical axis due to the oscillating wave, a rotation bearing disposed between the motor rotor and the third clutch wheel, and a rotation force transmitting member disposed between the motor rotor and the third clutch wheel to transmit power.

When a rotation force is input from the ring-shaped oscillating motor, the rotation force may be transmitted to the third clutch wheel through the rotation force transmitting member, and the at least one roller may roll along an outer surface of the third clutch wheel without a displacement difference with one surface of the at least one roller contacting the operator of the first clutch wheel and both ends of the at least one roller supported by the third elastic member, in order to disconnect a transmission of the input rotation force from the ring-shaped oscillating wave motor to the first and second clutch wheels.

When the rotation force is input from the ring-shaped oscillating wave motor, a transmission of the rotation force to the manual adjustment ring may be disconnected.

When a rotation force is input from the manual adjustment ring, the rotation force of the manual adjustment ring may be transmitted to the first clutch wheel, the rotation force transmitted to the first clutch wheel may be transmitted to the second clutch wheel through the first elastic members, a displacement difference may occur between the first and second clutch wheels through the second elastic member, and the at least one roller may generate a lock between the operator of the first clutch wheel and the third clutch wheel due to the displacement difference to transmit the rotation force to the third clutch wheel and the distance adjustment ring.

When the rotation force is input from the ring-shaped oscillating wave motor, the rotation force may be input from the manual adjustment ring.

Retaining torque of the motor case may be greater than torque of the distance adjustment ring, retaining torque of the manual adjustment ring may be greater than the retaining torque of the motor case, and sliding torque caused by a friction force occurring between the motor stator and the motor rotor may be greater than the retaining torque of the manual adjustment ring.

The lens barrel may further include a rotation angle expanding apparatus which is disposed between the manual adjustment ring and the clutch assembly and that expands a rotation angle of the manual adjustment ring and transmits the expanded rotation angle to the distance adjustment ring through the clutch assembly.

The rotation angle expanding apparatus may include at least one electric roller which is disposed on an outer surface of the first clutch wheel.

A ratio between rotation angles of the manual adjustment ring and the distance adjustment ring may be 2:1.

A manual connection ring may be disposed between the manual adjustment ring and the first clutch wheel, and a fourth elastic member may be disposed between the manual adjustment ring and the manual connection ring.

Torque occurring between the manual adjustment ring and the manual connection ring may be greater than torque of the distance adjustment ring.

According to another embodiment, a photographing apparatus includes a body and the lens barrel coupled with the body, the lens barrel transmitting image light of a subject through a lens to the body.

As described above, a lens barrel and a photographing apparatus including the lens barrel according to various embodiments provide the following effects.

A transmission of a rotation force of a distance adjustment ring rotated by a ring-shaped oscillating wave motor to a manual adjustment ring may be intercepted. Also, a rotation force generated by rotating the manual adjustment ring may be transmitted to the distance adjustment ring. Thus, an MF operation may be performed when an AF operation is being performed.

A motor stator may not be directly rotated by a rotation force input from the manual adjustment ring, but the rotation force of the manual adjustment ring may be transmitted to a motor rotor. A large space for rotating a motor case may not be needed around the motor stator, thereby increasing a freedom degree of design.

A rotation angle expanding apparatus may be installed on a clutch assembly but not around the motor rotor. Thus, a freedom degree of a design space increases, and thus the photographing apparatus may be made compact.

DETAILED DESCRIPTION

Exemplary embodiments will now be described in detail with reference to the attached drawings.

FIG. 1is a schematic perspective view of a photographing apparatus, according to an embodiment.

As shown inFIG. 1, a photographing apparatus10according to the present embodiment is a digital single-lens reflex camera whose lens may be attached thereto or detached therefrom.

While the photographing apparatus10according to the present embodiment is the digital single-lens reflex camera, this should not be construed as limiting. In other words, a type and a form of a photographing apparatus according to various embodiments are not limited. For example, photographing apparatuses having various types and forms, such as a compact camera, a video camcorder, or the like, may be applied as the photographing apparatus according to various embodiments.

The photographing apparatus10includes a lens group110, a lens barrel100, and a body20.

The lens group110transmits image light of a subject and includes a zoom lens, a focus lens, an aperture, and the like. The zoom lens moves back and forth on an optical axis to continuously change its focal length so as to capture a subject with a size of the subject changed. The focus lens adjusts a focus. The aperture adjusts an amount of light entering an imaging device when the photographing apparatus10is capturing an image of the subject.

The body20includes a shutter (not shown), the imaging device (not shown), an image processor (not shown), a viewfinder (not shown), a controller which performs an auto-focusing (AF) function and controls an internal motor, and the like. The body20receives the image light through the lens group110and performs capturing.

The lens barrel100according to the present embodiment will now be described in detail with reference toFIGS. 2 through 5.

FIG. 2is a schematic cross-sectional view of a part of the lens barrel100, according to an embodiment.FIG. 3is a perspective view of some elements of the lens barrel100ofFIG. 2, according to an embodiment.FIG. 4is a plan view of the elements ofFIG. 3, according to an embodiment.FIG. 5is a cross-sectional view of a clutch assembly, according to an embodiment.

As shown inFIGS. 2 through 5, the lens barrel100according to the present embodiment includes a manual adjustment ring130, an electric roller140, a ring-shaped oscillating wave motor150, a clutch assembly170, and a distance adjustment ring180.

The manual adjustment ring130, the ring-shaped oscillating wave motor150, the clutch assembly170, and the distance adjustment ring180are disposed between a body part120and a fixing part121. The body part120forms an outer surface of the lens barrel100, and the fixing part121forms an inner surface of the lens barrel100.

The manual adjustment ring130is disposed at an outer edge of the lens barrel100, and a user directly holds the manual adjustment ring130to rotate the lens barrel100.

The manual adjustment ring130is connected to a manual connection ring131. Therefore, a rotation force generated by the manual adjustment ring130is transmitted to the manual connection ring131.

In the present embodiment, the manual connection ring131is connected to the electric roller140. The rotation force transmitted to the manual connection ring130is transmitted to a first clutch wheel171through the electric roller140.

At least one or more electric rollers140are disposed at an outer surface of the first clutch wheel171to rotate in a rotation direction of the first clutch wheel171. If a plurality of electric rollers140are disposed at the outer surface of the first clutch wheel171, they may be disposed symmetrical to an optical axis Xo.

In the present embodiment, the electric roller140operates as a rotation angle expanding apparatus which increases a rotation angle of the distance adjustment ring180formed by the manual adjustment ring130with respect to a rotation angle of the distance adjustment ring180formed by driving the ring-shaped oscillating wave motor150. This will be described in more detail later.

The ring-shaped oscillating wave motor150includes a motor stator151and a motor rotor152. The motor stator151generates an oscillating wave, and the motor rotor152frictionally contacts the motor stator151and rotates on the optical axis Xo due to the oscillating wave.

A motor case (not shown) is installed at the fixing part121to rotate on the optical axis Xo and houses the motor stator151and the motor rotor152. Retaining torque of the motor case works toward the motor stator151through a pressure reducing member122of the body part120. In the present embodiment, sliding torque caused by a frictional force between the motor stator151and the motor rotor152is designed to be greater than the retaining torque of the motor case.

A rotation force generated by the motor rotor152is transmitted to a third clutch wheel175through a rotation force transmitting structure160.

In the present embodiment the rotation force transmitting structure160includes, a rotation bearing161for transmitting the rotation force of the motor rotor152. A rotation connection pin162is disposed at an outer surface of the rotation bearing161and rotates to be combined with the distance adjustment ring180. The rotation connection pin162is connected to an adjustment connection ring165, and a spring163and a spring force adjustment ring164are disposed between the rotation bearing161and the adjustment connection ring165. Here, the spring163is used for a frictional contact, and the spring force adjustment ring164adjusts a spring force of the spring163.

However, several components of the rotation force transmitting structure160have been described as examples and are not limited thereto. Thus, the rotation force transmitting structure160may be designed using components having various types of structures.

The clutch assembly170is disposed on a plane orthogonal to the optical axis Xo between the manual adjustment ring130and the distance adjustment ring180. The clutch assembly170is disposed to rotate on the fixing part121.

ReferringFIG. 2, the clutch assembly170includes the first clutch wheel171which is an external wheel, a second clutch wheel173which is an intermediate wheel, a third clutch wheel175which is an internal wheel, and a roller177.

The rotation force of the manual adjustment ring130is transmitted to the first clutch wheel171through the electric roller140.

Referring toFIG. 5, an operator172is disposed at an end of the first clutch wheel171. In the present embodiment, the operator172has a slope symmetrical to an axis Lo perpendicular to the optical axis Xo, and a surface of the roller177contacts an operating groove172aformed by the slope.

The second clutch wheel173is disposed on an inner surface of the first clutch wheel171.

The first and second clutch wheels171and173are flexibly fixed to each other by a pair of first elastic members174.

The first elastic members174are disposed symmetrically with respect to the operator172. The first elastic members174include first and second support parts174aand174b, wherein the first support parts174aenclose the outer surface of the first clutch wheel171, and the second support parts174bpenetrate through the first and second clutch wheels171and173. A pair of first support parts174aand a pair of second support parts174bare disposed symmetrically with respect to the operator172.

A second elastic member176is disposed between the second clutch wheel173and the fixing part121. The second elastic member176attenuates torque of the second clutch wheel173working on the fixing part121. In the present embodiment, the torque of the second clutch wheel173caused by the second elastic member176is designed to be greater than torque of the first clutch wheel171caused by the first elastic members174.

A third elastic member178is disposed at both ends of the second clutch wheel173, supports both ends of a circumferential surface of the roller177, and controls a position of the roller177along with the operator172. In the present embodiment, a plate spring is used as the third elastic member178, but various types of forms such as a compressive coil spring or the like may be applied as the third elastic member178.

The third clutch wheel175is disposed on an inner surface of the second clutch wheel173.

The third clutch wheel175is fixed to the distance adjustment ring180to move a focus of the lens group110. As described above, the third clutch wheel175is connected to the ring-shaped oscillating wave motor150to rotate on the ring-shaped oscillating wave motor150.

The roller177is disposed between the third and second clutch wheels175and173.

At least one or more rollers177may be radially disposed on the optical axis Xo, surfaces of the rollers177may contact the operator172, and other surfaces of the rollers177may contact an outer surface of the third clutch wheel175.

The distance adjustment ring180drives a lens to move a position of the lens. When a focus is in an AF state, i.e., a signal is being input through a press of a shutter button of the photographing apparatus10, the distance adjustment ring180drives the focus by driving force of the ring-shaped oscillating motor150. When the focus is in an MF state, the distance adjustment ring180drives the focus lens using a rotation force received from manipulation of the manual adjustment ring130.

A detailed MF operation performed during an AF operation through the lens barrel100according to the present embodiment will now be described.

FIG. 6is an enlarged view of a portion of the clutch assembly170when a rotation force of the ring-shaped oscillating wave motor150is not transmitted to the manual adjustment ring130, according to an embodiment.

An AF operation performed by the ring-shaped oscillating wave motor150will be described with reference toFIG. 6.

When a user presses the shutter button of the photographing apparatus10to start the AF operation, the motor stator151of the ring-shaped oscillating wave motor150generates an oscillating wave, and a rotation force is input through the motor rotor152.

The rotation force input through the motor rotor152is transmitted to the third clutch wheel175through the rotation force transmitting structure160which includes the rotation bearing161, the rotation connection pin162, the spring163, the spring force adjustment ring164, and the adjustment connection ring165.

Since the third clutch wheel175is fixed to the distance adjustment ring180, the rotation force transmitted to the third clutch wheel175is transmitted to the distance adjustment ring180.

The rotation force transmitted to the distance adjustment ring180drives the lens group110to adjust a focus of the optical system.

When the rotation force is not being input from the manual adjustment ring130, i.e., only the AF operation is performed, the rotation force is not directly input from the manual adjustment ring130to the first and second clutch wheels171and173.

Therefore, when both ends of the roller177disposed on the outer surface of the third clutch wheel175are supported by the third elastic member178, the roller177rolls on the outer surface of the third clutch wheel175in the operating groove172awithout a displacement difference with respect to the symmetrical axis Lo of the operating groove172a. Here, a central axis passing the symmetrical axis of the operator172and the ends of the roller177matches with the axis Lo perpendicular to the optical axis Xo.

The rotation force input to the third clutch wheel175is not transmitted to the first and second clutch wheels171and173due to a rolling motion of the roller177. Therefore, the rotation force is not transmitted to the manual adjustment ring130connected to the first clutch wheel171.

As a result, the lens barrel100according to the present embodiment intercepts the transmission of the rotation force input from the ring-shaped oscillating wave motor150to the manual adjustment ring130during the AF operation.

An input of the rotation force from the manual adjustment ring130to the distance adjustment ring180during the AF operation will now be described.

FIG. 7is an enlarged view of a portion of the clutch assembly170when the rotation force of the manual adjustment ring130is transmitted to the distance adjustment ring180, according to an embodiment.

Referring toFIG. 7, a rotation force input from the manual adjustment ring130connected to the manual connection ring131is transmitted to the manual connection ring131and the electric roller140. The rotation force transmitted to the electric roller140is transmitted to the first clutch wheel171.

The rotation force transmitted to the first clutch wheel171is transmitted to the second clutch wheel173which is elastically connected to the first elastic members174.

Torque of the second clutch wheel173caused by the second elastic member176is designed to be greater than torque of the first clutch wheel171caused by the first elastic members174. Thus, the second elastic member176disposed between the second clutch173and the fixing part121attenuates the rotation force transmitted to the second clutch wheel173.

Thus, since a relative displacement occurs between the first and second clutch wheels171and173, a displacement difference Δ occurs on a rotation path of the first and second clutch wheels171and173.

The displacement difference Δ generates a lock on the roller177whose ends are supported by the third elastic member178and which is disposed in the operating groove172a. Here, a central axis, which passes through the symmetrical axis of the operator172and the ends of the roller177, generates a displacement difference Δ with respect to the axis Lo perpendicular to the optical axis Xo.

The lock working on the roller177leads the roller177to slide on an outer surface of the third clutch wheel175and not to roll on the outer surface of the third clutch wheel175. Thus, the rotation force input from the manual adjustment ring130is transmitted to the third clutch wheel175due to a sliding friction force occurring between the third clutch wheel175and the roller177.

Since the third clutch wheel175is fixed to the distance adjustment ring180, the rotation force transmitted to the third clutch wheel175is transmitted to the distance adjustment ring180.

The rotation force transmitted to the distance adjustment ring180drives the lens group110to adjust the focus of the optical system.

The third clutch wheel175is connected to the rotation force transmitting structure160to transmit the rotation force along with the ring-shaped oscillating wave motor150. Thus, the rotation force input from the distance adjustment ring180is transmitted to the motor rotor152of the ring-shaped oscillating wave motor150.

In the lens barrel100according to the present embodiment, the retaining torque of the motor case of the ring-shaped oscillating wave motor150is greater than the torque of the distance adjustment ring180, retaining torque of the manual adjustment ring130is greater than the retaining torque of the motor case, and sliding torque caused by a friction force between the motor stator151and the motor rotor152is greater than the retaining torque of the manual adjustment ring130.

Therefore, the rotation force transmitted from the distance adjustment ring180is transmitted to the motor rotor152, and the motor stator151is not directly rotated by the rotation force transmitted to the motor rotor152, but the motor case is moved by the rotation force. Thus, the MF operation is performed when the AF operation is being performed.

When the rotation force input from the manual adjustment ring130is removed in this state, the displacement difference Δ between the second and first clutch wheels173and171disappears. Thus, the locking effect on the roller177is released as shown inFIG. 6.

According to the lens barrel100of the present embodiment, an MF operation is performed when an AF operation is being performed. A transmission of the rotation force of the distance adjustment ring180rotated by the ring-shaped oscillating wave motor150to the manual adjustment ring130is disconnected. The rotation force generated when the manual adjustment ring130is rotated rotates the distance adjustment ring180by interposing the clutch assembly170between the manual adjustment ring130and the distance adjustment ring180.

Typically, if a motor case is rotated by rotating a motor stator, an intermediate transmitting structure and a distance indicating index part are to be installed between a manual adjustment ring and the motor stator, wherein the intermediate transmitting structure transmits a rotation force of the manual adjustment ring to the motor stator. Thus, a product may become bigger.

However, the lens barrel100according to the present embodiment does not directly rotate the motor stator151using the rotation force input from the manual adjustment ring130but transmits the rotation force to the motor rotor152. Thus, a large space for rotating the motor case is not needed around the motor stator151.

In the present embodiment, the electric roller140is disposed on the outer surface of the first clutch wheel171. The rotation input from the manual adjustment ring130is transmitted to the clutch assembly170due to a rotation force generated by a frictional contact of the electric roller140and then finally transmitted to the distance adjustment ring180.

Here, the electric roller140operates as a rotation angle expanding apparatus which expands a ratio between rotation angles of the manual adjustment ring130and the distance adjustment ring180. For example, if the ratio between the rotation angles of the manual adjustment ring130and the distance adjustment ring180is 2:1, a ratio of a rotation angle of the distance adjustment ring180caused by the manual adjustment ring130to a rotation angle of the distance adjustment ring180caused by the ring-shaped oscillating wave motor150also increases to 2:1. Thus, a rotation of the distance adjustment ring180is precisely adjusted.

Friction retaining torque between the manual adjustment ring130and the manual connection ring131is designed to be greater than torque of the distance adjustment ring180, wherein a frictional contact between the manual adjustment ring130and the manual connection ring131is maintained by the fourth elastic member132. Thus, the manual adjustment ring130and the manual connection ring131rotate together. Here, if a rotation force input from the manual adjustment ring130is greater than or equal to an allowed rotation angle of the distance adjustment ring180, the frictional contact between the manual adjustment ring130and the manual connection ring131is released. Thus, transmission of rotation from the manual adjustment ring130to the manual connection ring131is disconnected so as to protect the distance adjustment ring180.

Accordingly, the lens barrel100according to the present embodiment installs the clutch assembly170at a narrow distance between the manual adjustment ring130and the distance adjustment ring180. The rotation angle expanding apparatus such as the electric roller140is installed on the clutch assembly170, and not around the motor stator151. Thus, a freedom degree of a design space increases, thereby facilitating making the photographing apparatus10compact.

A lens barrel of a photographing apparatus according to various embodiments does not necessarily include a rotation angle expanding apparatus.

FIG. 8is a schematic cross-sectional view of a part of a lens barrel200, according to another embodiment. The lens barrel200does not include a rotation angle expanding apparatus.

A clutch assembly270includes a first clutch wheel271, a second clutch wheel273, and a third clutch wheel275. Friction contact between a manual adjustment ring230and a manual connection ring232is maintained by a fourth elastic member231.

Since the lens barrel200does not include the rotation angle expanding apparatus for expanding and transmitting a rotation angle of the manual adjustment ring230, the rotation angle of the manual adjustment ring230is directly transmitted to the clutch assembly270, and a rotation angle of a distance adjustment ring280does not increase.

However, according to the lens barrel200of the present embodiment, a rotation force generated by rotating the manual adjustment ring230rotates the distance adjustment ring280by interposing the clutch assembly270between the manual adjustment ring230and the distance adjustment ring280.

The rotation force input from the manual adjustment ring230does not directly rotate a motor stator251but is transmitted to a motor rotor252. A large space for rotating a motor case is not needed around the motor stator251. Thus, a freedom degree of a design space increases, thereby facilitating the lens barrel200to be made compact.

The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural. Furthermore, recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No item or component is essential to the practice of the invention unless the element is specifically described as “essential” or “critical”.

While a lens barrel and a photographing apparatus including the lens barrel have been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.