WO2013062309A1

WO2013062309A1 - Camera module

Info

Publication number: WO2013062309A1
Application number: PCT/KR2012/008760
Authority: WO
Inventors: Min Soo Kim; Seon Young Kim
Original assignee: Lg Innotek Co., Ltd.
Priority date: 2011-10-28
Filing date: 2012-10-24
Publication date: 2013-05-02
Also published as: TW201330607A; TWI554097B

Abstract

present invention relates to a camera module including a first PCB (Printed Circuit Board) mounted with an image sensor, a housing unit arranged at an upper surface of the first PCB, a holder module spaced apart from an inner floor surface of the housing unit at a predetermined distance, wound at a periphery with a first coil and formed at an inside with at least one lens, a second PCB coupled to a floor surface of the holder module, a third PCB coupled to an upper surface of the holder module, a plurality of wire springs connected at one end to the second PCB and connected at the other end to the third PCB, and a buffer unit absorbing force applied to the holder module.

Description

CAMERA MODULE

The teachings in accordance with exemplary embodiments of this invention relate generally to a camera module applicable to smart phones and the like.

Small camera modules mounted on small electronic product often suffer from frequent shock during use. This is caused by subtle vibration from a user handshake or trembling of the camera module during photographing process. In consideration of the disadvantage, camera modules having anti-handshake means have been recently disclosed.

One known art in the related field, Korean Registered Patent No.10-0741823 (registered on July 16, 2007) teaches an hand-shake (hand vibration) compensation mechanism, where a gyro sensor IC (Integrated Circuit) or an angular velocity sensor is installed inside a device such as a mobile phone mounted with a camera module.

However, installation of a separate angular velocity sensor requires a separate detection sensor for realizing a handshake compensation function, resulting in an increased manufacturing cost and cumbersomeness requiring a space for configuring and installing a handshake prevention device aside from a camera module.

Thus, technical development to improve anti-handshake or handshake compensation function is required.

Accordingly, it is an object of the present invention to provide a camera module configured to have an OIS (Optical Image Stabilizer) function.

In order to accomplish the above object, in one general aspect of the present disclosure, there is provided a camera module, the camera module comprising: a first PCB (Printed Circuit Board) mounted with an image sensor; a housing unit arranged at an upper surface of the first PCB; a holder module spaced apart from an inner floor surface of the housing unit at a predetermined distance, wound at a periphery with a first coil and formed at an inside with at least one lens; a second PCB coupled to a floor surface of the holder module; a third PCB coupled to an upper surface of the holder module; a plurality of wire springs connected at one end to the second PCB and connected at the other end to the third PCB; and a buffer unit absorbing force applied to the holder module.

Preferably, but not necessarily, the buffer unit may be a buffer member interposed between the holder module and the third PCB.

Preferably, but not necessarily, the buffer member may be arranged on an entire surface facing the third PCB at the upper surface of the housing unit.

Preferably, but not necessarily, the buffer member may be provided by a shock-resistant member of microcellular polyurethane.

Preferably, but not necessarily, the third PCB may be a pad having a through hole at a center thereof through which the wire spring passes.

Preferably, but not necessarily, the buffer member may be spaced apart from a distal end of the through hole at a predetermined distance.

Preferably, but not necessarily, the buffer member may be spaced apart from a distal end of the pad at a predetermined distance.

Preferably, but not necessarily, the buffer member may be interposed between the distal end of the through hole and the distal end of the pad.

Preferably, but not necessarily, the housing unit may include a first housing arranged at an upper surface of the first PCB, a second housing arranged at an upper surface of the first housing, and mounted at an upper surface thereof with the third PCB, first and second permanent magnets interposed between the first and second housings; and a yoke interposed between the first and second permanent magnets, or positioned at an inner surface of the first and second housings to transmit a magnetic force into the holder module.

Preferably, but not necessarily, the yoke may be protrusively formed at a center proximity toward the holder module.

Preferably, but not necessarily, the camera module may further comprise a shield can having a through hole at a position corresponding to a connection unit between the third PCB and the wire spring and a lens module, and so installed as to wrap the housing unit.

Preferably, but not necessarily, the holder module may include an outer blade wound by a first coil at a periphery, a bobbin elastically supported at an upper surface of the outer blade by an elastic member, vertically-movable arranged at an inner surface of the outer blade, wound by a second coil at a periphery thereof and formed at an inner surface with at least more than one lens; and upper and bottom elastic members respectively arranged on an upper surface and a bottom surface of the bobbin to elastically support the bobbin relative to the outer blade.

Preferably, but not necessarily, the wire spring may be provided with a metal material and conductibly connected to the second and third PCBs.

Preferably, but not necessarily, at least six or more wire springs may be provided to supply two polarity powers for auto focusing control and four polarity powers for OIS driving through connection between the second and third PCBs.

Preferably, but not necessarily, a total of eight wire springs may be provided, each at a same length, and a set of two wire springs being arranged at each corner of the holder module.

Preferably, but not necessarily, the first coil may be centrally formed with a space unit to allow a magnetic force to be magnetized toward the second coil.

Preferably, but not necessarily, the bottom spring may be conductibly connected to the wire spring on the second PCB.

Preferably, but not necessarily, the wire spring may be movably support the holder module, and the buffer unit may be a buffer part bent at a certain section of the wire spring.

Preferably, but not necessarily, the buffer part may be formed at a proximity of connection unit between the wire spring and the third PCB.

Preferably, but not necessarily, the buffer part may be formed at a proximity of the connection unit between the wire spring and the third PCB and a proximity of a connection unit between the wire spring and the second PCB.

Preferably, but not necessarily, the buffer part may be formed at a proximity of the connection unit between the wire spring and the second PCB.

Preferably, but not necessarily, the buffer unit may be a shock absorber formed at a lateral wall of the housing unit to be elastically deformed at the time of generation of shock on the housing unit.

Preferably, but not necessarily, the housing unit may include a first housing arranged at an upper surface of the first PCB, a second housing arranged at an upper surface of the first housing and formed at an upper surface with the third PCB, first and second permanent magnets interposed between the first and second housings, and a yoke arranged between the first and second permanent magnets to transmit a magnetic force into the holder module, wherein the shock absorber is formed at the second housing.

Preferably, but not necessarily, the shock absorber may be formed at a lateral wall of the second housing.

Preferably, but not necessarily, the shock absorber may be provided by at least one or more grooves formed at the lateral wall of the second housing at a predetermined depth.

Preferably, but not necessarily, the shock absorber may be provided by at least three or more grooves formed at the lateral wall of the second housing each at a predetermined depth, and each groove has a same depth, spaced apart from neighboring groove at a predetermined distance, and is formed alternatively at an external lateral surface and an inner lateral surface of the second housing.

A camera module according to the present invention has an advantageous effect in that a wire spring is formed with a buffer unit to absorb a repetitively applied load and to be tightly connected to a connection unit of a PCB.

Another advantageous effect is that, even if a wire spring is applied with an excessive force amidst assembly process of lens module, a buffer member can absorb the excessively applied force to improve assembly and to minimize parts loss resultant from incomplete assembly as well.

FIG. 1 is a schematic plan view of a camera module according to an exemplary embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view taken along line A-A.

FIG.3 is a lateral view of a camera module according to a first exemplary embodiment of the present invention.

FIG.4 is a lateral view illustrating a state in which a shield can of FIG.3 is removed.

FIG. 5 is a schematic enlarged view illustrating a B part of FIG.2 according to a first exemplary embodiment of the present invention.

FIG.6 is a schematic cross-sectional view taken along line A-A of FIG.1 according to a second exemplary embodiment of the present invention.

FIG.7 is a schematic enlarged view of a C-part of FIG.6.

FIG.8 is a schematic cross-sectional view taken along line A-A according to a third exemplary embodiment of the present invention.

FIG.9 is a schematic cross-sectional view taken along line A-A according to a fourth exemplary embodiment of the present invention.

FIG.10 is a schematic cross-sectional view taken along line A-A according to a fifth exemplary embodiment of the present invention.

FIGS.11 and 12 are schematic enlarged views of a D-part of FIG.10, and schematic cross-sectional views illustrating an operation state of a shock absorber according to an exemplary embodiment of the present invention.

Now, the camera module according to exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a schematic plan view of a camera module according to an exemplary embodiment of the present invention, FIG. 2 is a schematic cross-sectional view taken along line A-A, FIG.3 is a lateral view of a camera module according to a first exemplary embodiment of the present invention, FIG.4 is a lateral view illustrating a state in which a shield can of FIG.3 is removed, FIG. 5 is a schematic enlarged view illustrating a B part of FIG.2 according to a first exemplary embodiment of the present invention, FIG.6 is a schematic cross-sectional view taken along line A-A of FIG.1 according to a second exemplary embodiment of the present invention.

FIG.7 is a schematic enlarged view of a C-part of FIG.6, FIG.8 is a schematic cross-sectional view taken along line A-A according to a third exemplary embodiment of the present invention, FIG.9 is a schematic cross-sectional view taken along line A-A according to a fourth exemplary embodiment of the present invention, FIG.10 is a schematic cross-sectional view taken along line A-A according to a fifth exemplary embodiment of the present invention, and FIGS.11 and 12 are schematic enlarged views of a D-part of FIG.10, and schematic cross-sectional views illustrating an operation state of a shock absorber according to an exemplary embodiment of the present invention.

Referring to FIG.1 of a schematic plan view of a camera module according to an exemplary embodiment of the present invention and FIG. 2 of a schematic cross-sectional view taken along line A-A, a camera module includes a first PCB (Printed Circuit Board, 10), a housing unit (20), a holder module (30), a second PCB (40), a third PCB (50) a wire spring (60) and a buffer member (100).

The first PCB (10) is mounted at an approximate center neighborhood thereof with an image sensor (11) and is preferably provided by a PCB substrate. The PCB (10) may be arranged with constituent elements for operating the image sensor (11), or with a plurality of terminal units configured to output information of the image sensor (11).

The housing unit (20) is arranged at an upper surface of the first PCB (10) to form a skeleton of the camera module. The housing unit (20) according to an exemplary embodiment of the present invention includes a first housing (21), a second housing (22), first and second permanent magnets (23, 24) and a yoke (25).

The first housing (21) is a base to be arranged at an upper surface of the first PCB (10) and spaced apart from the image sensor (11) at a predetermined distance. The first housing (21) may be further mounted with a filter member configured to filter an image incident on the image sensor (11). The second housing (22) is arranged at an upper surface of the first housing (21) to cover the first housing (21). The second housing (22) is formed at an approximate center neighbor with an opening unit to transmit an image to a side of the image senor (10). The second housing (22) is adhesively fixed at an upper surface with the third PCB (50, described later) using a fixing member such as a double-side tape or an adhesive. The present invention is not limited thereto. For example, it is possible to provide a separate third PCB with a case or a shield can and to fix the third PCB (50) at an inner lateral wall using the fixing member according to product design. In a case the third housing is provided, the third housing may supportively press the third PDB (50) without any separate fixing member.

The first and second permanent magnets (23, 24) are interposed between the first and second housings (21, 22) to magnetize the holder module (30). The first and second permanent magnets (23, 24) are preferably provided in the same size. Furthermore, the first and second housings (21, 22) and the yoke (25) may be arranged at an inner lateral surface of the first and second housings (21, 22) within a design allowance, if possible.

Meanwhile, in a case the first and second permanent magnets (23, 24) are enlarged, an OIS driving increases even with a small current, and in a case the first and second permanent magnets (23, 24) are configured each with a predetermined size, the OIS driving comes to increase as a current flowing in first and second coils (31a, 32a) arranged at a position corresponding to the first and second permanent magnets (23, 24) increases. In conclusion, as the sizes of the first and second permanent magnets (23, 24) increase, the OIS driving improves. However, an optical sized design is preferable within other design allowances.

The yoke (25) is interposed between the first and second permanent magnets (23, 24). The yoke (25) is protrusively formed at an approximate center to allow magnetic force of the first and second permanent magnets (23, 24) to be magnetized into an inner space of the holder module (30). Preferably, a width of the yoke is same as that of each of the first and second permanent magnets (23, 24), and a center of the yoke (25) is protruded to allow the permanent magnet and the yoke to take a shape of an approximate "T" form.

The holder module (30) is spaced apart from an inner floor surface of the housing unit (20) at a predetermined distance, and includes an outer blade (31) and a bobbin (32). The holder module (30) can perform a pendular movement horizontally/vertically and diagonally while being hung from the wire spring (60). The outer blade (31) is formed at an upper surface and a bottom surface with spring members (35, 36), elastically supported by the spring member (35) and connected to allow the bobbin (32) to vertically move.

The outer blade (31), as shown in FIG.1, is wound with a total of four first coils (31a~31d) at a periphery of four lateral surfaces, and a center portion of the four lateral surfaces wound with coils (31a~31d) is hollow with no coils. It is possible to arrange a yoke (25) at a position corresponding to the hollow space and a part of the yoke (25) to be inserted into the space.

The outer blade (31) may be fixed at a bottom surface with the second PCB (40) using a fixing member (33) such as a double-sided tape or an adhesive. The outer blade (31) is hung by a plurality of wire springs (60) for movement to forward/backward, left/right and diagonal directions as shown in arrows of FIG.2 by the magnetic force of the first and second permanent magnets (22, 23) and interaction of the first coil (31a) and is arranged spaced apart from the floor surface of the first housing (21) at a predetermined distance. The outer blade (31) may be provided with a plurality of spring through holes (37) to allow the wire spring (60) to pass and to be connected to the second PCB (40).

The bobbin (32) is vertically-movably arranged at an inner surface with the outer blade (31), and is formed at an inner surface with at least one or more sheets of lenses. The bobbin (32) is wound at a periphery with the second coil (332a), where the second coil (32a) performs an operation of up-lifting and down-lifting the bobbin (32) in response to an interaction with the magnetic force magnetized through an open space minus of the first coils (31a~31d) of the outer blade (31) using the yoke (25). Although a larger size of the yoke (25) enables an AF driving. However, the size of the yoke (25) must be also changed according to an optimal design value. Thus, it is possible to automatically adjust an image focus transmitted to the image sensor (11) by lifting operation of the bobbin (32).

The second PCB (40) is arranged at a floor surface of the outer blade (31), as explained before, to be connected to the wire spring (60) to supply an electric power to the first and second coils (31a, 32a). The connecting method may be by way of soldering or other conductive materials. However, the method is not limited thereto. That is, a connection unit (w ) of the second PCB (40), as illustrated in FIG.2, is connected to the first and second coils (31a, 32a) to allow the electric power received through the wire spring (60) to be transmitted to the first and second coils (31a, 32a), whereby an electromagnetic force can be formed.

At this time, the second coil (32a) may be directly connected to the second PCB (40), or may be connected to a bottom spring (36), as shown in FIG.2, to allow the bottom spring (36) to be connected to the second PCB (40).

The third PCB (50) is fixed to an upper surface of the second housing (22) using a fixing member such as a double-sided tape or an adhesive as explained above, where an electric power transmitted to a terminal unit (52) of the third PCB (50) connected to the first PCB (10) is transmitted to the second PCB (40) through the wire spring (60) connected to the second PCB (40). The connecting method may be by way of soldering or other conductive materials. However, the method is not limited thereto.

Referring to FIGS. 3 and 4, the third PCB (50) is so provided as to cover a lateral wall surface of the first and second housings (21, 22), where a surface opposite to the first and second permanent magnets (23, 24) and the yoke (32) may be formed with a window to prevent interference therewith. This configuration is to prevent interference because the first and second permanent magnets (23, 24) and the yoke (32) are directly attached to a shield can (70, described later) using fixing means such as epoxy.

Meanwhile, the second and third PCBs may be an FPCB (Flexible PCB), a PCB, or an R-FPCB (Rigid-FPCB), but may not be limited thereto and may be any substrates that can be electrically conducted. The wire spring (60) is connected at both distal ends to the second and third PCBs (40, 50). At this time, a distal end of the wire spring (60) is connected to a pad (51) formed at the third PCB (50), where a center of the pad (51) is formed with a through hole (53) through which the wire spring (60) passes. The connecting method may be by way of soldering or other conductive materials. However, the method is not limited thereto. Meanwhile, a surrounding of the pad (51) is provided with a solder register to protect a surface of the third PCB (50), and an area of the pad (51) may be connectible by opening the solder register.

Thus, the wire spring (60) connected from the pad (51) supplies the received electrical power to the second PCB (40) side, where the first and second coils (31a, 32a) can be interacted with the first and second permanent magnets (23, 24). Furthermore, the other distal end of the wire spring (60), albeit not being illustrated, is connected to a pad (not shown) formed at the second PCB (40) as in the third PCB (50), where a center of the pad (not shown) is formed with an opening (not shown) through which the wire spring (60) passes. The connecting method may be by way of soldering or other conductive materials. However, the method is not limited thereto.

According to the configuration thus described, the outer blade (31) may be hung from the wire spring to be spaced apart from a floor surface of the first housing (21) at a predetermined distance. As a result, the outer blade (31) performs a pendular movement in response to an interaction between the first coil (31a) and the first and second permanent magnets (23, 24) to compensate vibration of the outer blade (31) caused by the handshake through the interaction between the first coil (31a) and the first and second permanent magnets (23, 24). To this end, the wire spring (60) is preferably provided with a conductible metal material having elasticity capable of withstanding shocks.

Meanwhile, although it is better for the wire spring (60) to be thinner for better handshake compensation movement, the thickness of the wire spring (60) may be changed according to an optimal design value. Preferably, the thickness of the wire spring (60) is several μm to several hundredμm, and more preferably, 1μm to 100μm.

In addition, at least six wire springs (60) are preferably provided, and at least two polarity powers for auto focusing control and four polarity powers for handshake compensation are needed to be supplied to the holder module (30) through connection with the second and third PCBs (40, 50).

According to an exemplary embodiment of the present invention, a total of eight wire springs (60) are balancingly provided, each at a same length, and a set of two wire springs are arranged at each corner of the holder module (30), as illustrated in FIGS. 1 and 2.

Meanwhile, as illustrated in FIG.2, in a case a separate third housing such as a shield can (70) is further included in the camera module according to the exemplary embodiment of the present invention, the third PCB (50) is formed with a window (55) to cover a lateral wall surface of the first and second housings (21, 22), whereby a coupled part between the first and second permanent magnets (23, 24) and the yoke (25) can be avoided, because the first and second permanent magnets (23, 24) and the yoke (25) are fixedly coupled to the shield can (70) using epoxy.

Meanwhile, in a case a configuration is the one free from the shield can (70), it is possible to form the third PCB (50) with a PCB or the like, and to fixedly attach the first and second permanent magnets (23, 24) and the yoke (25) thereinside. Alternatively, the third PCB (50) may be formed with a PCB, and a window (55) may be provided, where the window (55) may be inserted by the first and second permanent magnets (23, 24) and the yoke (25), and a shielding tape may be additionally reinforced thereoutside.

The buffer member (100) is interposed between the second housing (22) and the third PCB (50) to absorb a force generated by a pad (51) provided at the third PCB (50) for connecting the wire spring (60) and the third PCB (50), or a force generated from the wire spring (60) to dispersively absorb a load applied to a connection unit (w).

A diameter of the through hole (53) is preferably a bit greater than that of the wire spring (60). Furthermore, when connection is made at the pad (51) formed at the wire spring (60) and the third PCB (50), the through hole (53) may be so designed as to allow a connection material such as a soldering and conductive material to flow through and to allow being fixedly connected to the wire spring (60) at both upper and bottom surfaces of the third PCB (50).

A diameter of a support hole (122) is preferably a bit greater than that of the wire spring (60), which is a design to prevent interference caused by the wire spring (60) being in contact with the second holder (22) near to the support hole (122).

According to an exemplary embodiment of the present invention, the buffer member (100) is preferably arranged on an entire surface opposite to the third PCB (50) at an upper end of the second housing (22). Although not illustrated, the buffer member (100) may be formed at a surrounding of the connection unit (w).

The buffer member (100) may be provided with a shock-resistant member of microcellular polyurethane foam. One of the exemplary microcellular polyurethane foams may be PORON (a trademark of Japanese INOAC and US Rogers). However, the present invention is not limited thereto and any materials capable of being elastically deformed by an external force may be used.

The buffer member (100) may be spaced apart from each distal end of the pad (51) and the through hole (53) at a predetermined distance to prevent the third PCB (50) from being torn apart. Referring to FIG.5, the buffer member (100) may be interposed between a distal end of the through hole (53) and a distal end of the pad (51) to fix the third PCB (50) and the second housing (22) to reduce a load directly applied to the connection unit (w) fixing the wire spring (60).

Furthermore, the buffer member (100) can perform the buffering function by being arranged between the third PCB (50) and the second housing (22) at a distal end of the support hole (122), or at a position spaced apart at a predetermined distance from the distal end of the support hole (122).

Meanwhile, a general assembly order is to first couple the bobbin (32) to the outer blade (31), to connect the second housing (22), the second and third PCBs (40, 50) to the wire spring (60) using a jig, and to couple the bobbin (32) provided with a lens barrel to connect the first housing (21), which is then mounted to the first PCB (10). The permanent magnets and yoke may be coupled prior to connection of the first housing (21). The assembly order may be changed if necessary. That is, a direct assembly may be possible without using a jig. In the assembly process, even if a force fixedly inserting the bobbin (32) provided with the lens barrel is too excessively applied to thereby provide an unnecessary load to the connection unit (w), the buffer member (100) can absorb the excessive force.

That is, as illustrated in FIGS. 2 and 5, because, the buffer member (100) is so arranged as to surface-contact the pad (51), in a case a load is generated on the wire spring (60) and pulled to a gravitational direction, or horizontally shaken, the load is initially applied to the pad (51), and the force applied to the pad (51) is in turn applied to the buffer member (100) and deformed, where the load energy is absorbed by the buffer member (100) as a deformed energy. Thus, the cumbersomeness of re-performing the connection operation caused by broken connection unit (w) during the assembly process or by useless parts can be prevented.

Meanwhile, the camera module according to an exemplary embodiment of the present invention may further comprise a shield can (70) having a through hole at a position corresponding to the lens module (30) at the surrounding of the connection unit (w) of the wire spring (60) and the third PCB (50), and so installed as to wrap the housing units (21, 22). In this case, the third PCB (50), as explained above, can be fixedly attached to an inner surface of the shield can (70). However, the shield can (70) is not an essential part, but may be omitted according to configuration of the housing units (21, 22).

Now, referring to FIG.2, the shield can (70) may be formed with a hook unit (80) on at least one surface or four surfaces in order to fix the first housing (21). The position may be at a center or a margin within an allowable design, and the number of shield cans may be one or more than one. The hook unit (80) may include a hook (81) protruded from the first housing (21), and a hook hole (82) so formed as to pass through the shield can (70) opposite to the hook (81), and if necessary, the opposite configuration is also possible.

Hereinafter, a camera module according a second exemplary embodiment of the present invention will be described with reference to the accompanying drawings, where like reference numerals will be applied as in the first exemplary embodiment of the present invention.

A buffer unit (100) according the second exemplary embodiment of the present invention may be integrally formed at a partial section of the wire spring (60). Referring to FIGS. 6 and 7, the buffer unit (100) may be respectively formed at the connection unit (w) between the wire spring (60) and the third PCB (50), and a connection unit (w') near the wire spring (60) and the second PCB (40). At this time, the buffer unit (100) is preferred to have first and second bending units (110, 120) at positions not interfering the second housing (22). However, the present invention is not limited thereto, and the bending units may be bent twice to absorb a load applied to the wire spring (60) at the bent positions, if necessary.

That is, as illustrated in FIG.6, the first and second bending units (110, 120) may be a moment center of the bent wire spring (60) according to a load applied to the wire spring (60) to be deformed to a direction where the bent wire spring (60) is straightened. Thus, the deformation functions to absorb the load applied to the wire spring (60) about each of the first and second bending units (110, 120), whereby a load applied to the pad (51) provided at the third PCB (50) can be alleviated, and a load directly applied to the connection unit (w) fixing the wire spring (60) can be also alleviated.

A camera module according to a third exemplary embodiment of the present invention is configured such that the buffer unit (100) may be formed only at the vicinity of the connection unit (w) between the wire spring (60) and the third PCB (50). That is, because the connection unit (w) between the wire spring (60) and the third PCB (50) is a position where a concentrated load of the wire spring (60) hanging the holder module (30) is applied, a relatively greater force is applied compared with the connection unit (w') connected to the second PCB (40) installed on the floor surface of the outer blade (31). Thus, the buffer member (100) may be formed only at a position near to the connection unit (w) between the wire spring (60) and the third PCB (50).

Furthermore, the buffer unit (100) according to a fourth exemplary embodiment of the present invention may be formed only at a position near to the connection unit (w') between the wire spring (60) and the second PCB (40), as shown in FIG.9.

Of course, as explained above, although the position where the concentrated load is applied is the connection unit (w) between the wire spring (60) and the third PCB (50), and even if the buffer unit (100) is formed at a vicinity of the connection unit (w') between the wire spring (60) and the second PCB (40) existing on an extended line of the load, the load absorption is generated at this position as in the first and second exemplary embodiments of the present invention to resultantly reduce the load applied to the connection unit (w) between the wire spring (60) and the third PCB (50).

A shock absorber (100) may be formed at a lateral wall of the second housing (22) according to a fifth exemplary embodiment of the present invention. The shock absorber (100) , as illustrated in FIGS.10, 11 and 12, may be provided in the shape of at least one or more grooves at the lateral wall of the second housing (22) at a predetermined depth. The shock absorber (100) formed in the shape of a groove may have a depth smaller than the thickness of the second housing (22). The shock absorber (100) may be provided with at least one or more grooves on an entire lateral wall of the second housing (22) at a predetermined depth.

At this time, each groove has the same depth and may be formed spaced apart from a neighboring groove at a predetermined distance. Furthermore, the shock absorber (100) may be alternatively formed on an external lateral surface and an inner lateral surface of the second housing (22), as illustrated in the drawings.

In a case the shock absorber (100) is formed, and because a cross-section of the lateral wall of the second housing (22) is formed in a zigzagged shape, and when an external shock is applied to the second housing (22), wall surfaces of both sides of the shock absorber (100) each formed in the shape of a groove as shown in FIG.6 come closer to elastically deform the second housing (22), whereby the external shock energy may be transformed into displacement energy. Therefore, the shock absorber (100) can resultantly absorb the external shock through the elastic deformation of the second housing (22) to reduce the load caused by movement of the holder module (30) transmitted to the connection unit (w) between the wire spring (60) and the third PCB (50), whereby damage to the connection unit (w) can be minimized.

The previous description of the present invention is provided to enable any person skilled in the art to make or use the invention. Various modifications to the invention will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other variations without departing from the spirit or scope of the invention. Thus, the invention is not intended to limit the examples described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

As apparent from the foregoing, the camera module according to the exemplary embodiments of the present invention has an industrial applicability in that it can be applied to a camera module mounted on a small electronic device such as a mobile phone or a tablet PC.

Claims

A camera module, the camera module comprising: a first PCB (Printed Circuit Board) mounted with an image sensor; a housing unit arranged at an upper surface of the first PCB; a holder module spaced apart from an inner floor surface of the housing unit at a predetermined distance, wound at a periphery with a first coil and formed at an inside with at least one lens; a second PCB coupled to a floor surface of the holder module; a third PCB coupled to an upper surface of the holder module; a plurality of wire springs connected at one end to the second PCB and connected at the other end to the third PCB; and a buffer unit absorbing force applied to the holder module.
The camera module of claim 1, wherein the buffer unit is a buffer member interposed between the holder module and the third PCB.
The camera module of claim 2, wherein the buffer member is provided by a shock-resistant member of microcellular polyurethane foam.
The camera module of claim 2, wherein the third PCB is a pad having a through hole at a center thereof through which the wire spring passes, and wherein the buffer member is spaced apart at a predetermined distance from any one of a distal end of the through hole and a distal end of the pad.
The camera module of claim 4, wherein the buffer member is interposed between the distal end of the through hole and the distal end of the pad.
The camera module of claim 2, wherein the housing unit includes a first housing arranged at an upper surface of the first PCB, a second housing arranged at an upper surface of the first housing, and mounted at an upper surface thereof with the third PCB, first and second permanent magnets interposed between the first and second housings; and a yoke interposed between the first and second permanent magnets, or positioned at an inner surface of the first and second housings to transmit a magnetic force into the holder module, and wherein a space unit is formed at a center of the first coil to allow the magnetic force to be transmitted toward the second coil.
The camera module of claim 2, further comprising a shield can, the can having a through hole at a position corresponding to a connection unit between the third PCB and the wire spring and a lens module, and so installed as to wrap the housing unit.
The camera module of claim 2, wherein the holder module includes an outer blade wound by a first coil at a periphery, a bobbin elastically supported at an upper surface of the outer blade by an elastic member, vertically-movable arranged at an inner surface of the outer blade, wound by a second coil at a periphery thereof and formed at an inner surface with at least more than one lens; and upper and bottom elastic members respectively arranged on an upper surface and a bottom surface of the bobbin to elastically support the bobbin relative to the outer blade.
The camera module of claim 2, wherein the wire spring is provided with a metal material to be conductibly connected to the second and third PCBs, and wherein at least six or more wire springs are provided to supply to the holder module two polarity powers for auto focusing control and four polarity powers for OIS driving through connection between the second and third PCBs.
The camera module of claim 9, wherein a total of eight wire springs are provided, each at a same length, and a set of two wire springs being arranged at each corner of the holder module.
The camera module of claim 8, wherein the second coil is conductively connected to a bottom spring and the bottom spring is conductibly connected to the wire spring on the second PCB.
The camera module of claim 1, wherein the wire spring is movably support the holder module, and the buffer unit is a buffer part bent at a predetermined section of the wire spring.
The camera module of claim 12, wherein the buffer part is formed at a proximity of connection unit between the wire spring and the third PCB.
The camera module of claim 12, wherein the buffer part is formed at a proximity of the connection unit between the wire spring and the third PCB and a proximity of a connection unit between the wire spring and the second PCB as well.
The camera module of claim 12, wherein the buffer part is formed at a proximity of the connection unit between the wire spring and the second PCB.
The camera module of claim 1, wherein the buffer unit is a shock absorber formed at a lateral wall of the housing unit to be elastically deformed at the time of generation of shock on the housing unit.
The camera module of claim 16, wherein the housing unit includes a first housing arranged at an upper surface of the first PCB, a second housing arranged at an upper surface of the first housing and formed at an upper surface with the third PCB, first and second permanent magnets interposed between the first and second housings, and a yoke arranged between the first and second permanent magnets to transmit a magnetic force into the holder module, wherein the shock absorber is formed at the second housing.
The camera module of claim 17, wherein the shock absorber is formed at a lateral wall of the second housing.
The camera module of claim 18, wherein the shock absorber is provided by at least one or more grooves formed at the lateral wall of the second housing at a predetermined depth, and wherein each groove is formed with a depth of a value smaller than a thickness of the second housing.
The camera module of claim 17, wherein the shock absorber is provided by at least three or more grooves formed at the lateral wall of the second housing each at a predetermined depth, and each groove has a same depth, spaced apart from a neighboring groove at a predetermined distance, and is formed alternatively at an external lateral surface and an inner lateral surface of the second housing.