Zoom lens system

A zoom lens system including at least one lens group that is positioned to be movable along an optical axis of image light for photographing; and a movable frame including a plurality of selection lens groups, the movable frame being movable between a photographing position and a storage position, wherein the photographing position is a position in which one of the selection lens groups is selectively positioned on the optical axis, and the storage position is a position in which all of the selection lens groups are outside the optical axis, and the movable frame including a storage portion that houses at least a portion of the at least one lens group when the movable frame is moved to the storage position.

CROSS-REFERENCE TO RELATED PATENT APPLICATION

This application claims the priority benefit of Korean Patent Application No. 10-2009-0119101, filed on Dec. 3, 2009, 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 zoom lens system, and in particular, to a zoom lens system having a lens storage space for reducing the thickness of the zoom lens system and for selecting a lens group having a different performance according to purpose of use.

2. Description of the Related Art

Zoom lens systems form an image by passing image light through various optical elements and are widely used in photographing apparatuses such as digital cameras or video cameras. In addition, use of a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS) enables manufacturing of small and thin photographing apparatuses. However, in order to manufacture thinner photographing apparatuses, components of the photographing apparatuses should have a small thickness.

A conventional zoom lens system may be a retractable zoom lens system or a folded-optics zoom lens system. According to the retractable zoom lens system, in order to manufacture slim photographing apparatuses, lenses protrude during photographing and retract into a body of a camera when not in use. According to the folded-optics zoom lens system, the thickness of a lens system is reduced by using a reflective element such as a prism to fold the optical path of the zoom lens system.

With regards to the retractable zoom lens system, a plurality of lens groups are aligned and movable along an optical axis, and when the zoom lens system is not in use, the lens groups retract into a body of a camera. In order to minimize the thickness of the zoom lens system, the lens groups are aligned with as little space as possible therebetween when the lens groups retract into the body of the camera.

However, the retractable zoom lens system has a structural limitation in that even when lens groups retract into a body of a camera, the thickness of the zoom lens system is not smaller than the sum of thicknesses of the lens groups.

Zoom lens systems have various optical characteristics according to the lens groups used. A user selects a zoom lens system according to purpose of use of a photographing apparatus. For example, if a user takes a landscape picture, the user selects a wide angle zoom lens system having an excellent wide-angle performance and a wide viewing angle, and if a user takes a picture of a distant subject, the user selects a tele-angle zoom lens system including lens groups having a narrow viewing angle and a long focal length. Thus, since the user needs to buy various zoom lens systems according to a photographing purpose, the photographing costs are increased and exchanging with a desired zoom lens system during photographing is inconvenient.

SUMMARY

Embodiments include a zoom lens system that minimizes a lens storage space.

Embodiments also include a zoom lens system that embodies various optical performances using the one zoom lens system.

Embodiments also include a zoom lens system in which a user selects at least one lens group from a plurality of lens groups according to a photographing purpose without exchanging the zoom lens system.

Embodiments also include a zoom lens system in which a storage space for lens groups is obtained by placing a plurality of lens groups outside an optical axis when the lens groups retract.

According to an embodiment, a zoom lens system facilitates the selection of a variety of lens groups and provides an extended optical performance by including a movable frame that includes a plurality of selection lens groups. The movable frame may be moved between a photographing position and a storage position, wherein the photographing position is a position in which one of the selection lens groups is selectively positioned on the optical axis, and the storage position is a position in which all of the selection lens groups are outside the optical axis.

The zoom lens system includes: at least one lens group that is movable along an optical axis; and a movable frame including a plurality of selection lens groups, the movable frame being movable between a photographing position and a storage position, wherein the photographing position is a position in which one of the selection lens groups is selectively positioned on the optical axis, and the storage position is a position in which all of the selection lens groups are outside the optical axis. The movable frame further includes a storage portion that houses at least a portion of the at least one lens group when the movable frame is moved to the storage position.

The movable frame may be rotatable, and the selection lens groups and the storage space may be positioned on a common circle centered on a rotation center of the movable frame.

The movable frame may rotate with respect to a shaft that is parallel to the optical axis.

The movable frame may be movable along a straight line, and the selection lens groups and the storage portion may be positioned along the straight line along which the movable frame moves.

The selection lens groups may include a first selection lens group having a wide-angle function and a second selection lens group having a high magnification zoom function.

The at least one lens group may include a first lens group and a second lens group positioned in front of the movable frame and a third lens group positioned behind the movable frame, all aligned along the optical axis.

The movable frame may be movable along the optical axis.

The selection lens groups may include a first selection lens group and a second selection lens group, wherein the first and second selection lens groups have different focal distances.

According to another embodiment, a zoom lens system includes: a plurality of lens groups that are movable along an optical axis; and a plurality of selection lens groups that are selectively positioned on the optical axis, wherein one of the selection lens groups is selectively positioned on the optical axis to select any one of a plurality of optical systems, and when the plurality of lens groups are moved to be close to each other along the optical axis for storage, all of the selection lens groups are positioned outside the optical axis to secure a storage portion for the plurality of lens groups.

DETAILED DESCRIPTION

Hereinafter, the structure and operation of various embodiments of a zoom lens system will be described in with reference to the attached drawings.

FIG. 1is a cross-sectional view of lens groups of a zoom lens system aligned in an operation state, according to an embodiment.

Referring toFIG. 1, the zoom lens system according to the present embodiment includes first, second, and fifth lens groups10,20, and50which are aligned and movable along an optical axis L, a plurality of selection lens groups30and40, a movable frame70that is movable in a direction perpendicular to the optical axis L, and a storage portion75included in the movable frame70. In the zoom lens system ofFIG. 1, other components for supporting the first, second, and fifth lens groups10,20, and50are not illustrated in order to more clearly explain relative motions and position relationships between the first, second, and fifth lens groups10,20, and50and the movable frame70.

The first, second, and fifth lens groups10,20, and50are aligned and may be movable along the optical axis L. The first lens group10is disposed as a frontmost lens group with respect to image light and thus image light enters the first lens group10first, and then the second lens group20and the fifth lens group50are sequentially disposed behind the first lens group10along the optical axis L.

The first, second, and fifth lens groups10,20, and50may be movable along the optical axis L, and distances among the first, second, and fifth lens groups10,20, and50may be adjusted to control a zoom function and a focal distance. InFIG. 1, the first, second, and fifth lens groups10,20, and50and the movable frame70are moved toward a front side of the zoom lens system along the optical axis L to take a picture.

The movable frame70may be movable along a direction Ds that crosses the optical axis L. The movable frame70may include the selection lens groups30and40, and is movable in a range from a photographing position in which any one of the selection lens groups30and40is selected and positioned on the optical axis L, to a storage position in which all the selection lens groups30and40are positioned outside the optical axis L.

FIG. 2is a cross-sectional view illustrating another operation state of the zoom lens system ofFIG. 1, according to an embodiment.

The movable frame70may be moved upward along the direction Ds, which crosses the optical axis L, to position the selection lens group40on the optical axis L. That is, the movable frame70may be positioned in a first photographing position, as illustrated inFIG. 1. The movable frame70may also be moved downward along the direction Ds to position the selection lens group30on the optical axis L. That is, the movable frame70may be positioned in a second photographing position, as illustrated inFIG. 2. During photographing, the movable frame70may be positioned in the first photographing position or the second photographing position, according to user selection.

As described above, in the zoom lens system according to the present embodiment, any one of the selection lens groups30and40may be selected and positioned on the optical axis L and thus one of a plurality of optical systems may be selected. That is, when the third lens group30is positioned on the optical axis L, the first, second, and fifth lens groups10,20, and50and the third lens group30may form a first optical system. In addition, when the fourth lens group40is positioned on the optical axis L, the first, second, and fifth lens groups10,20, and50and the fourth lens group40may form a second optical system.

The selection lens groups30and40may include the third lens group30and the fourth lens group40. Although according to the present embodiment, the selection lens groups30and40include two lens groups, the invention is not limited thereto. For example, the selection lens groups may include three or four lens groups.

The third lens group30and the fourth lens group40may have different optical characteristics. The third lens group30may be a wide-angle lens group that realizes a super wide-angle mode of the zoom lens system, and the fourth lens group40may be a general zoom lens group that performs a general zoom function. However, the optical characteristics of the third lens group30and the fourth lens group40are not limited thereto, and lens groups having different optical characteristics may also be used as the third lens group30and the fourth lens group40. For example, the third lens group30may be a high magnification zoom lens group that realizes a high magnification zoom function.

FIG. 3is a cross-sectional view of the zoom lens system ofFIGS. 1 and 2when the first, second, and fifth lens groups10,20, and50of the zoom lens system retract, according to an embodiment.

The movable frame70may be moved to the storage position, in which the selection lens groups30and40are positioned outside the optical axis L, as illustrated inFIG. 3. The storage position refers to a position of the zoom lens system when the zoom lens system is not in use. When the movable frame70is positioned in the storage position, lens barrels of the zoom lens system are collapsed.

The movable frame70may include the storage portion75that houses at least a portion of the first, second, and fifth lens groups10,20, and50when the zoom lens system is in the storage position. According to the present embodiment, the storage portion75houses the second lens group20.

When the first, second, and fifth lens groups10,20, and50of the zoom lens system retract, the movable frame70is moved to the storage position and the first lens group10and the second lens group20, which are positioned in front of the movable frame70, and the fifth lens group50are moved toward the movable frame70along the optical axis L so that spaces between the movable frame70and the first, second, and fifth lens groups10,20, and50are minimized. The movements of the movable frame70and the first, second, and fifth lens groups10,20, and50may occur simultaneously. In this regard, an interval between the first lens group10and the second lens group20is minimized and the second lens group20enters the storage portion75of the movable frame70. Accordingly, when the first, second, and fifth lens groups10,20, and50of the zoom lens system retract, the thickness of the zoom lens system may be reduced by an amount corresponding to the thickness of the second lens group20. As described above, when the first, second, and fifth lens groups10,20, and50retract, all the selection lens groups30and40are outside the optical axis L and thus a storage space for at least one of the first, second, and fifth lens groups10,20, and50may be secured.

FIG. 4is a schematic perspective view illustrating components of the zoom lens system ofFIGS. 1,2, and3, according to an embodiment.

The movable frame70is aligned and movable along a straight line Ls that crosses the optical axis L. The selection lens groups30and40are aligned along the straight line Ls along which the movable frame70may be moved, and the storage portion75of the movable frame70is also aligned along the straight line Ls.

In the present embodiment illustrated inFIG. 4, a driving unit that drives the movable frame70along the straight line Ls may include a motor80, a driving gear72coupled to a shaft81of the motor80, and a rack gear surface71that is formed at an outer surface of the movable frame70and that is engaged with the driving gear72. When the motor80operates, a rotary motion of the driving gear72is transferred to the rack gear surface71and thus the movable frame70may move upward or downward along the straight line Ls.

FIG. 5is a schematic perspective view illustrating components of a zoom lens system, according to another embodiment.

Referring toFIG. 5, the zoom lens system according to the present embodiment includes first, second, and fifth lens groups110,120, and150aligned along an optical axis L, a plurality of selection lens groups130and140, a movable frame170that is rotatable in directions that cross the optical axis L, and a storage space175included in the movable frame170. In the zoom lens system ofFIG. 5, other components for supporting first, second, and fifth lens groups110,120, and150are not illustrated in order to more clearly explain relative motions and position relationships among the first, second, and fifth lens groups110,120, and150and the movable frame170.

The first, second, and fifth lens groups110,120, and150are aligned and may be movable along the optical axis L. The first lens group110is disposed as a frontmost lens group with respect to image light and thus image light enters the first lens group110first, and then the second lens group120and the fifth lens group150are sequentially disposed behind the first lens group110along the optical axis L.

The first, second, and fifth lens groups110,120, and150may be movable along the optical axis L, and distances among the first, second, and fifth lens groups110,120, and150may also be adjusted to control a zoom function and a focal distance. InFIG. 5, the first, second, and fifth lens groups110,120, and150and the movable frame170are moved toward a front side of the zoom lens system along the optical axis L to take a picture.

The movable frame170has a rotation center171athat is connected to a shaft181of a motor180and that rotates with respect to the shaft181, which is parallel to the optical axis L. Thus, the movable frame170may rotate in directions that cross the optical axis L.

The movable frame170may include the selection lens groups130and140and is movable in a range between a photographing position and a storage position. The photographing position is a position in which any one of the selection lens groups130and140may be selected and positioned on the optical axis L and the storage position is a position in which all of the selection lens groups130and140are positioned outside the optical axis L. That is, the movable frame170may rotate clockwise from the position illustrated inFIG. 5to position the selection lens group140on the optical axis L, which may be referred to as a first photographing position. On the other hand, the movable frame170may rotate counterclockwise from the position illustrated inFIG. 5to position the selection lens group130on the optical axis L, which may be referred to as a second photographing position.

The movable frame170may include the storage space175for housing the second lens group120. The selection lens groups130and140may be positioned on a circle171bcentered on the rotation center171aof the movable frame170. The storage space175may also be positioned on the circle171b. Thus, when the motor180operates, the movable frame170rotates and the third lens group130may be positioned on the optical axis L, that is, at the second photographing position, the fourth lens group140may be positioned on the optical axis L, that is, at the first photographing position, or the storage space175may be positioned on the optical axis L, that is, at the storage position.

However, the structure for rotating the movable frame170is not limited to that as illustrated inFIG. 5and other structures may be used. For example, as illustrated inFIG. 4, a structure in which a gear surface is formed in the movable frame170and a driving gear coupled to the shaft181of the motor180is engaged with the gear surface may also be used.

As described above, in the zoom lens system according to the present embodiment, one of a plurality of optical systems may be selected by selecting any one of the selection lens groups130and140and positioning the selected lens group. That is, when the third lens group130is positioned on the optical axis L, the first, second, and fifth lens groups110,120, and150and the third lens group130may form a first optical system. On the other hand, when the fourth lens group140is positioned on the optical axis L, the first, second, and fifth lens groups110,120, and150and the fourth lens group140may form a second optical system.

FIG. 6is a schematic perspective view of the zoom lens system ofFIG. 5when the first, second, and fifth lens groups110,120, and150of the zoom lens system retract, according to an embodiment.

The movable frame170may be rotated to be in the storage position as illustrated inFIG. 6, in which all of the selection lens groups130and140are positioned outside the optical axis L. The storage position refers to a position in which the zoom lens system is not in use and lens barrels of the zoom lens system are collapsed.

The movable frame170may include the storage space175that houses at least a portion of the first, second, and fifth lens groups110,120, and150when the zoom lens system is in the storage position. According to the present embodiment, the storage space175houses the second lens group120.

When the first, second, and fifth lens groups110,120, and150of the zoom lens system retract, the movable frame170is moved to the storage position and the first lens group110and the second lens group120, which are positioned in front of the movable frame170, and the fifth lens group150move toward the movable frame170. The movements of the movable frame170and the first, second, and fifth lens groups110,120, and150may occur simultaneously. An interval between the first lens group110and the second lens group120is minimized, and the second lens group120enters the storage space175of the movable frame170. Thus, when the first, second, and fifth lens groups110,120, and150of the zoom lens system retract, the thickness of the zoom lens system may be reduced by an amount corresponding to the thickness of the second lens group120.

FIG. 7is a cross-sectional view of lens groups of a zoom lens system and lens barrels for the lens groups, according to another embodiment. The zoom lens system illustrated inFIG. 7is the same as the zoom lens systems illustrated inFIGS. 5 and 6, except that in a storage position, only a portion of a second lens group120is stored in a storage space175of a movable frame170.

A first lens group110, the second lens group120, the movable frame170, a fifth lens group150, and an imaging device190may be disposed along an optical axis L.

The imaging device190is positioned at a base167, and a fixed lens barrel164is coupled to the base167. A first lens barrel161, a second lens barrel162, and a third lens barrel163may be disposed in front of the fixed lens barrel164and may be movable forward or backward along the optical axis L.

The first, second, and third lens barrels161,162, and163support the first, second, and fifth lens groups110,120, and150, respectively, and are moved forward or backward by using a driving unit such as a cam mechanism or a motor (not shown). Since an inner guide165that supports the movable frame170is also coupled to the first, second, and third lens barrels161,162, and163, which may be moved by the cam mechanism, the movable frame170may be moved along the optical axis L forward or backward.

InFIG. 7, a top portion indicated by an arrow A represents a first photographing position in which a fourth lens group140is positioned on the optical axis L, and a bottom portion indicated by an arrow B represents a second photographing position in which a third lens group130is positioned on the optical axis L.

When a zoom lens system having the structure described above is used, photographing may be performed by selecting any one of the selection lens groups130and140having different optical characteristics according to a photographing purpose. Thus, various photographing modes may be realized without exchanging of the zoom lens system.

FIG. 8is a cross-sectional view of the zoom lens system ofFIG. 7when the first, second, and fifth lens groups110,120, and150of the zoom lens system retract, according to an embodiment.

When the first, second, and fifth lens groups110,120, and150and the movable frame170of the zoom lens system are housed in the fixed lens barrel164, the first, second, and third lens barrels161,162, and163supporting the first, second, and fifth lens groups110,120, and150are moved into the fixed lens barrel164. In this regard, the movable frame170may be rotated to be in the storage position, in which the selection lens groups130and140are positioned outside the optical axis L and the storage space175is positioned on the optical axis L. When the zoom lens system is positioned in the storage position, the second lens group120is stored in the storage space175.

When the first, second, and fifth lens groups110,120, and150of the zoom lens system retract, a portion of the second lens group120is housed in the storage space175of the movable frame170. Thus, when the first, second, and fifth lens groups110,120, and150of the zoom lens system retract, the selection lens groups130and140are not on the optical axis L and thus a space for a portion of the first, second, and fifth lens groups110,120, and150is secured.

In the embodiments illustrated with reference toFIGS. 7 and 8, the zoom lens system is integrally coupled to an imaging device, that is, a camera mounting lens barrel assembly is illustrated. However, the invention is not limited to the structure described above. For example, the zoom lens system according to various embodiments may be coupled to a exchangeable lens camera. Thus, unlike the embodiments illustrated inFIGS. 7 and 8, the zoom lens system may also be embodied as a zoom lens assembly including only lens groups and a movable frame.

In the previous embodiments described above, the movable frame170is automatically moved by applying a control signal by using a driving unit, but the invention is not limited thereto. For example, the movable frame may be installed to be manually movable in a direction perpendicular to the optical axis L, so that a user may select any one of a plurality of selection lens groups according to a photographing purpose.

Zoom lens systems according to various embodiments may realize many various optical modes using only one lens assembly and thus may be used in various applications. For example, zoom lens systems according to various embodiments may be applied to compact electronic devices such as mobile phones to realize a camera function having two or more focal distances. Thus, more various functions may be realized compared to a conventional mobile phone including a camera having only one focal distance.

Also, although a conventional zoom lens system for cars may be used only for use in parking, if zoom lens systems according to the various embodiments are applied to cars, other functions, including supervising external circumstances for an anti-theft purpose, identifying a road condition during driving, and supervising for a safe driving purpose may also be realized.

Also, in cases in which zoom lens systems according to various embodiments are used in a surveillance camera of a closed-circuit television (CCTV), when a still image is taken using the surveillance camera, a viewing angle or a zoom region may be changed and thus the appliance range may be widened.

The zoom lens systems according to the above embodiments may have various optical characteristics using only one zoom lens system by selecting a portion of selection lens groups included in a movable frame since when the movable frame is rotated to be positioned in a photographing position, a portion of selection lens groups is selectively positioned on an optical axis. That is, without exchanging of the zoom lens system, one selection lens group satisfying a photographing purpose may be selected from a plurality of selection lens groups. A camera using the zoom lens systems may facilitate a user taking a picture more conveniently.

In addition, when lens groups of the zoom lens systems retract, the movable frame is rotated so that all the selection lens groups are positioned outside the optical axis and at least a portion of the lens groups is housed in a storage space of the movable frame. Thus, the thickness of a zoom lens system may be minimized when the lens groups retract.

The apparatus described herein may comprise a processor, a memory for storing program data to be executed by the processor, a permanent storage such as a disk drive, a communications port for handling communications with external devices, and user interface devices, including a display, keys, etc. When software modules are involved, these software modules may be stored as program instructions or computer readable code executable by the processor on a non-transitory computer-readable media such as read-only memory (ROM), random-access memory (RAM), CD-ROMs, magnetic tapes, floppy disks, and optical data storage devices. The computer readable recording media may also be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion. This media can be read by the computer, stored in the memory, and executed by the processor.