AF carrier feedback control-type camera module

Abstract

The present invention relates to an AF carrier feedback control-type camera module. The present invention comprises: a housing providing a mounting space and having an optical path; an OIS carrier mounted in the housing and including a plurality of magnets; an AF carrier accommodated in the OIS carrier, an AF coil being wound around the outer portion thereof so as to correspond to the magnets, and the AF coil being adjustable in position in the optical axis direction; a lens module mounted on the AF carrier; a driving unit configured to move the AF carrier in the optical axis direction and, if the OIS carrier is eccentric, move the OIS carrier such that the center of the lens module is aligned with the center of the housing optical path; an AF displacement amount sensing unit configured to operate if the AF carrier moves, thereby acquiring displacement amount information of the AF carrier; and a camera control unit configured to receive displacement amount information from the AF displacement amount sensing unit and control the driving unit on the basis of the received information. The AF carrier feedback control-type camera module of the present invention, configured as described above, can electrically connect the AF carrier to an external camera control unit, thereby enabling feedback control and implementing quick and accurate autofocusing through precise control of the AF carrier.

Description

AF carrier feedback control camera module

[0001] The present invention relates to a camera module mounted on a portable electronic device, and more specifically, to an AF carrier feedback control type camera module that enables precise control of an AF carrier, thereby implementing autofocusing very quickly and accurately.

[0002] Cameras in recently released smartphones and other portable electronic devices incorporate a variety of cutting-edge technologies. These include features like autofocusing and image stabilization.

[0003] Image stabilization is a function that helps obtain a relatively good image even when the mobile electronic device shakes when taking a picture. Electronic and optical image stabilization are known.

[0004] Electronic image stabilization technology is a technology that improves the captured image through a process method using software, etc., and optical image stabilization (OIS) technology is a technology that prevents shaking from being reflected in the image of the subject generated on the image sensor by physically correcting the position of the lens module or image element caused by hand shaking, etc.

[0005] Meanwhile, autofocus control in existing camera modules is achieved through simple current control. For example, by adjusting the current value, the AF carrier is moved, thereby adjusting the lens position.

[0006] However, this type of control has the disadvantage of not being able to receive feedback on the precise position of the lens module. In other words, while the lens moves according to the current value, there is no feedback on whether the lens has moved accurately. This can lead to excessive or insufficient lens movement, resulting in inaccurate focus or prolonged focusing times. These problems inevitably negatively impact image quality.

[0007] In this regard, Korean Patent Publication No. 10-2011-0108183 (Camera module capable of auto-focusing and method for manufacturing the same) has been disclosed.

[0008] The disclosed camera module comprises a module upper assembly having a liquid lens for focusing and a printed circuit board for a lens that supplies power to the liquid lens and is electrically connected to the liquid lens, and a module lower assembly having an image sensor that converts subject light incident through the liquid lens into an image, a main printed circuit board that electrically connects the image sensor to the outside, and a module base on which the image sensor and the main printed circuit board are supported, and the module upper assembly is fixedly attached to the module lower assembly so that the relative position of the liquid lens with respect to the image sensor is determined.

[0009] The purpose of the present invention is to provide an AF carrier feedback control type camera module capable of implementing rapid and accurate autofocusing through precise control of the AF carrier by enabling feedback control.

[0010] As a technical solution for achieving the above object, the AF carrier feedback control type camera module of the present invention comprises: a housing having a mounting space open to the top and an optical path; an OIS carrier having a plurality of magnets and capable of moving in a direction perpendicular to the optical axis direction while mounted in the housing; an AF carrier accommodated inside the OIS carrier, having an AF coil wound on an outer side corresponding to the magnets and capable of adjusting the position in the optical axis direction; a lens module mounted on the AF carrier; a driving unit that moves the AF carrier in the optical axis direction and moves the OIS carrier when the OIS carrier is eccentric to align the center of the lens module with the center of the optical path of the housing; an AF displacement amount detection unit that operates when the AF carrier moves to obtain displacement amount information of the AF carrier; and a camera control unit that receives displacement amount information from the AF displacement amount detection unit and controls the driving unit based on the received information.

[0011] In addition, the driving unit includes an outer FPCB that surrounds the housing and has a terminal portion on one side, a pair of X driving coils that are fixedly connected to the outer FPCB and correspond one-to-one to some magnets and are installed on opposite sides with an OIS carrier therebetween, and a pair of Y driving coils that are fixedly connected to the outer FPCB and correspond one-to-one to the remaining magnets and are installed on opposite sides with an OIS carrier therebetween.

[0012] In addition, the AF displacement detection unit is mounted on the AF carrier and includes an internal sensor that detects movement of the AF carrier, an internal IC chip connected to the internal sensor, and an internal FPCB that surrounds the AF carrier and is connected to the internal IC chip.

[0013] In addition, as a means of connecting the inner FPCB and the outer FPCB, an elastic connector that is connected to the AF coil and the inner FPCB and is elastically deformable, and an FPCB spring that connects the elastic connector and the outer FPCB are further included.

[0014] In addition, the elastic connector has a terminal connection portion connected to the AF coil and the internal FPCB, a spring connection portion connected to the FPCB spring, and an extension portion that connects the terminal connection portion and the spring connection portion and is elastically deformable according to the movement of the AF carrier.

[0015] In addition, the FPCB spring includes a first connection portion connected to the spring connection portion, a second connection portion connected to an external FPCB, and a bending portion that connects the first connection portion and the second connection portion and has a bent shape and is elastically deformable.

[0016] In addition, the external FPCB is formed with a connection tab portion that is fixed to the second connection portion in a folded state.

[0017] The AF carrier feedback control type camera module of the present invention, which is constructed as described above, can electrically connect the AF carrier to an external camera control unit, thereby enabling feedback control and enabling rapid and accurate autofocusing through precise control of the AF carrier.

[0018] FIG. 1 is a side view of an AF carrier feedback control type camera module according to one embodiment of the present invention.

[0019] Fig. 2 is a perspective view showing the shield can of the camera module illustrated in Fig. 1 separated.

[0020] Figure 3 is an exploded perspective view of a camera module according to one embodiment of the present invention.

[0021] FIG. 4 is a drawing for explaining a control signal transmission and reception path in a camera module according to one embodiment of the present invention.

[0022] Figure 5 is a plan view of a camera module according to one embodiment of the present invention.

[0023] Hereinafter, one embodiment according to the present invention will be described in more detail with reference to the attached drawings.

[0024] FIG. 1 is a side view of an AF carrier feedback control type camera module according to one embodiment of the present invention, and FIG. 2 is a perspective view showing the shield can of the camera module illustrated in FIG. 1 in an exploded manner. In addition, FIG. 3 is an exploded perspective view of a camera module according to one embodiment of the present invention, and FIG. 4 is a drawing for explaining a control signal transmission and reception path in a camera module according to one embodiment of the present invention, and FIG. 5 is a plan view of a camera module according to one embodiment of the present invention.

[0025] The term "feedback control" in the title of the present invention refers to control that receives feedback on the position of the AF carrier (27). For example, if the camera control unit commands the AF carrier to move by 0.9 mm, it checks whether the AF carrier has actually moved by 0.9 mm and determines the operational precision based on the result. This feedback control has the characteristic of being able to significantly reduce the time required for autofocusing and the settling time.

[0026] For reference, previous camera modules were not designed to detect the actual movement distance of the AF carrier. While a signal was input to the AF carrier to move a certain amount, it did not verify whether the carrier had actually moved that distance.

[0027] As shown, the AF carrier feedback control type camera module (10) according to the present embodiment includes a housing (15), an OIS carrier (23), an AF carrier (27), a lens module (13), a driving unit, an AF displacement amount detection unit, and a camera control unit (40).

[0028] The housing (15) provides an upper open mounting space (15b) and has an optical path (15c) in the center. The housing (15) has a roughly square frame shape and has support planes (15a) at its four corners. As illustrated in Fig. 2, the support planes (15a) are horizontal planes that provide support so that the second connection portion (33e) and the connection tab portion (17c) can be in close contact with each other. The housing (15) is wrapped around an external FPCB (17), which is part of the drive unit. The drive unit will be described later.

[0029] The OIS carrier (20) is capable of moving in a direction orthogonal to the optical axis while mounted in the housing (15). The OIS carrier (20) includes a carrier body (23a) and four magnets (23f). The carrier body (23a) has a shape of a square frame that is open at the top. In addition, magnets (23f) are mounted on the four sides of the carrier body (23a). The magnets (23f) face the X-drive coil (19a) and the Y-drive coil (19b) described later. In addition, a bending portion receiving groove (23b) is formed at the vertex of the carrier body (23a). The bending portion receiving groove (23b) is a space in which the bending portion (33c) of the FPCB spring is received.

[0030] The AF carrier (27) is accommodated inside the OIS carrier (23) and is positionally adjustable in the optical axis direction. The AF carrier (27) has a carrier body (27a) and an AF coil (27c). A space is formed in the center of the carrier body (27a), and a lens module (13) is fixed to the space. The AF carrier (27) and the lens module (13) form one body and move together. The AF coil (27c) is a coil wound on the outer surface of the carrier body (27a) and corresponds to a magnet (23f).

[0031] Meanwhile, the driving unit moves the AF carrier (27) in the direction of the optical axis, and when the OIS carrier (23) is eccentric, moves the OIS carrier to align the center of the lens module (13) with the center of the housing optical path (15c). All components involved in moving the AF carrier (27) and the OIS carrier (23) can be included in the driving unit.

[0032] The OIS carrier (23) can be eccentric, tilted, or rotated around the optical axis in a direction orthogonal to the optical axis due to physical shaking. The driving unit returns the OIS carrier (23) to its normal position when such movement occurs. The return of the OIS carrier (23) to its normal position is also due to the action of the FPCB spring (33). The FPCB spring (33) assists the driving unit. In addition, the driving unit moves the AF carrier (27) in the optical axis direction, which is to focus the lens module on the subject.

[0033] The driving unit includes an external FPCB (17), a pair of X driving coils (19a), a first external IC chip (21a), a first sensor (21b), a pair of Y driving coils (19b), a second external IC chip (21d), and a second sensor (21e).

[0034] The external FPCB (17) is a flexible printed circuit board (FPCB) in the form of a band of a certain width and is tightly fixed to the outer surface of the housing (15). A terminal portion (17a) is provided on one side of the external FPCB (17). The terminal portion can be connected to a camera control unit (40). The camera control unit (40) is an element that controls the operation of the driving unit.

[0035] In particular, the external FPCB (17) is provided with four connection tab portions (17c). The connection tab portions (17c) are folded in the direction of arrow a toward the support plane portion (15a). The connection tab portions (17c) are folded in the direction of arrow a and are fixed to the upper surface of the second connection portion (33e) of the FPCB spring (33). The circuits of the FPCB spring (33) and the external FPCB (17) are electrically connected.

[0036] The X drive coil (19a) and the Y drive coil (19b) are connected to the circuit of the external FPCB (17) and are exposed toward the inside of the housing (15).

[0037] The X drive coil (19a) is installed on the opposite side with the OIS carrier (23) in between, and faces two magnets (23f). In addition, the Y drive coil (19b) is also installed on the opposite side with the OIS carrier (23) in between, and corresponds one-to-one to the remaining two magnets (23f). The imaginary straight lines connecting the two mutually opposing X drive coils (19a) and the imaginary straight lines connecting the Y drive coils (19b) are orthogonal to each other.

[0038] The first and second sensors (21b, 21e) are respectively arranged on the inner side of the X drive coil (19a) and the inner side of the Y drive coil (19b). The first and second sensors (21b, 21e) detect the movement of the OIS carrier (19). That is, the first sensor (21b) detects the X-direction movement of the OIS carrier (23), and the second sensor (21e) detects the Y-direction movement of the OIS carrier (23).

[0039] And, the first external IC chip (21a) is an electronic component that connects the first sensor (21b) and the external FPCB (17). The first external IC chip (21a) collects data measured by the first sensor (21b), processes it, and then transmits it to the external FPCB (17).

[0040] The second external IC chip (21d) is an electronic component that connects the second sensor (21e) and the external FPCB (17). The second external IC chip (21d) collects data measured by the second sensor (21e), processes it, and then transmits it to the external FPCB (17). Through the first and second external IC chips (21a, 21d) and the first and second sensors (21b, 21e), the shaking of the lens module (13) can be detected and corrected in real time.

[0041] Meanwhile, the AF displacement detection unit moves together with the AF carrier (27) as it moves in the Z direction and acquires displacement information of the AF carrier (27). That is, it detects the actual displacement of the AF carrier (27) and transmits the detected information to the outside.

[0042] The AF displacement detection unit includes an internal IC chip (27e), an internal sensor (27f), and an internal FPCB (29). The internal IC chip (27e) and the internal sensor (27f) are installed on one side of the carrier body (27a) and form one body with the carrier body (27a). That is, they move simultaneously.

[0043] The internal FPCB (29) is a band-shaped FPCB of a certain width and is installed in a manner of wrapping the AF carrier (27). The internal FPCB (29) is electrically connected to the terminal connection portions (31a) of four flexible connectors (31). In addition, the internal IC chip (27e) is also electrically connected to the internal FPCB (29).

[0044] The internal sensor (27f) detects the movement of the AF carrier (27) in the arrow Z direction and transmits the detected information to the internal IC chip (27e). The internal IC chip (27e) collects the data measured by the internal sensor (27f), processes it, and then transmits it to the internal FPCB (29). The displacement value of the AF carrier (27) in the optical axis direction is actually detected, and the detected data is fed back to the outside.

[0045] Meanwhile, a transmission path for transmitting the feedback signal from the internal FPCB (29) to the external FPCB (17), i.e., connecting the internal FPCB and the external FPCB, is provided with four elastic connectors (31) and four FPCB springs (33).

[0046] The elastic connector (31) is made of an electrically conductive metal and is symmetrical about the optical axis. The elastic connector (31) is electrically connected to the AF coil (27c) and the internal FPCB (29) and is elastically deformable. The elastic connector (31) serves both as a signal transmitter and as a spring that supports the AF carrier (27).

[0047] Each elastic connector (31) has a terminal connection portion (31a), a spring connection portion (31c), and an extension portion (31b). The terminal connection portion (31a) is connected to the internal FPCB (29) while being tightly fixed to the upper surface of the carrier body (27a). In addition, the terminal connection portion (31a) is also connected to the AF coil (27c).

[0048] The spring connection portion (31c) is a portion having a roughly circular arc shape, and as illustrated in Fig. 5, is covered by the first connection portion (33a) on the support surface (23d) of the carrier body (23a). The spring connection portion (31c) is electrically connected to the first connection portion (33a).

[0049] The extension portion (31b) connects the terminal connection portion (31a) and the spring connection portion (31c), and functions as a spring that can be elastically deformed according to the movement of the AF carrier. The extension portion (31b) can be elastically deformed according to the movement of the AF carrier (27). The AF carrier (27) can be positioned in a fixed position without external force being applied by receiving the elasticity of the extension portion (31b).

[0050] In addition, four FPCB springs (33) form a set and connect the elastic connector (31) and the external FPCB (17). The FPCB spring (33) has a first connection portion (33a), a second connection portion (33e), and a bending portion (33c).

[0051] The first connecting portion (33a) is electrically connected to the spring connecting portion (31c) while covering the spring connecting portion (31c). The spring connecting portion (31c) is covered by the first connecting portion (33a) and fixed to the upper surface of the carrier body (23a).

[0052] In addition, the second connection portion (33e) is a portion connected to the connection tab portion (17c) of the external FPCB. After the second connection portion (33e) is tightly fixed to the support flat portion (15a) of the housing (15), the connection tab portion (17c) is folded in the direction of arrow a to electrically connect it to the second connection portion (33e). The second connection portion (33e) and the connection tab portion (17c) can be fixed by soldering.

[0053] The bending portion (33c) connects the first connecting portion (33a) and the second connecting portion (33e), takes on a bent shape, and is an elastically deformable portion. The bending portion (33c) provides elasticity while being accommodated in the bending portion receiving groove (23b) of the carrier body (23a). The bending portion (33c) has both ends integrally formed with the first connecting portion (33a) and the second connecting portion (33e), and takes on a roughly U-shaped bent shape.

[0054] The bending portion (33c) elastically deforms according to the movement of the OIS carrier (23). For example, when the OIS carrier (23) moves, tilts, or rotates in a direction orthogonal to the optical axis, it elastically changes and applies an elastic restoring force to the OIS carrier (23). The elastic restoring force refers to an elastic force that positions the OIS carrier (23) correctly.

[0055] Meanwhile, the camera control unit (40) receives displacement information from the AF displacement detection unit and controls the driving unit based on the received information. The feedback data detected by the AF displacement detection unit is transmitted to the camera control unit (40) via the internal FPCB (29), elastic connector (31), FPCB spring (33), and external FPCB (17).

[0056] The shield can (11) is a cover that is detachably connected to the housing (15) and has a passage (11a) in the center. The passage (11a) is a hole through which the lens module (13) passes. The shield can (11) serves to protect the components housed in the housing (15).

[0057] The operation of the camera module (10) of this embodiment having the above configuration is as follows.

[0058] First, the user activates the camera function of the smartphone and then points the lens module (13) at the subject. However, if the subject is not in focus at this time, the camera control unit (40) operates to generate an electric signal to control the AF carrier (27). The camera control unit (40) generates the above-described signal when the AF algorithm running within the image processor (not shown) recognizes that the focus is not correct.

[0059] The control signal output from the camera control unit (40) is input to the terminal unit (17a). In addition, the signal input to the terminal unit (17a) is transmitted to the AF coil (27c) via the external FPCB, the FPCB spring (33), and the elastic connector (31). When an electric signal is transmitted to the AF coil (27c), the AF coil outputs an electromagnetic force and affects the magnet (23f). That is, when current is applied to the AF coil (27c), movement of the AF carrier (27) in the optical axis direction occurs according to Fleming's left-hand rule. At this time, the extension unit (31b) is elastically deformed.

[0060] As the AF carrier (27) moves in the optical axis direction, the AF displacement detection unit operates. That is, the internal sensor (27f) operates to detect the actual distance the AF carrier (27) has moved. The displacement information detected by the internal sensor (27f) is transmitted to the internal IC chip (27e), and then fed back to the camera control unit (40) through the internal FPCB (29), elastic connector (31), FPCB spring (33), and external FPCB (17). The camera control unit (40) determines the displacement accuracy of the AF carrier through the feedback data.

[0061] If the AF carrier (27) has moved by the exact distance, no additional signal is generated. However, if there is an error in the displacement amount, an additional signal is generated and re-input to the external FPCB (17). Through the above process, the exact position of the AF carrier (27) in the optical axis direction is determined. This process is completed almost instantaneously.

[0062] Meanwhile, while the AF carrier (27) moves, the OIS carrier (23) tries to maintain a fixed position by the action of the FPCB spring (33). The fixed position means a position where the optical axis line coincides with the central axis of the optical path (15c).

[0063] However, when the camera module (10) shakes while taking a picture, the OIS carrier (23) moves and the bending part (33c) of the FPCB spring (33) is elastically deformed. In addition, at this time, the first and second sensors (21b, 21e) detect the movement of the OIS carrier (19) and transmit the detection information to the first external IC chip (21a) and the second external IC chip (21d). The first and second external IC chips (21a, 21d) transmit the movement data of the OIS carrier (23) to the camera control unit (40).

[0064] The camera control unit (40) outputs a signal for positioning the OIS carrier based on the received data and transmits the signal to the external FPCB. The signal received by the external FPCB is transmitted to the X drive coil (19a) and the Y drive coil (19b). The X drive coil (19a) and the Y drive coil (19b) output electromagnetic force and return the eccentric OIS carrier (23) to the position. At this time, the bending portion (33c) is also elastically restored and assists in returning the OIS carrier (23) to the position. By repeating the above process, the problem caused by shaking of the camera module (10) is solved.

[0065] Above, the present invention has been described in detail through specific examples, but the present invention is not limited to the above examples, and various modifications are possible by a person of ordinary skill within the scope of the technical idea of ​​the present invention.

[0066] It is industrially applicable because it enables precise control of the AF carrier, enabling autofocusing to be implemented very quickly and accurately.

Claims

1. A housing having an open mounting space at the top and an optical path; An OIS carrier equipped with a plurality of magnets and capable of moving in a direction perpendicular to the optical axis while mounted within a housing; An AF carrier which is housed inside an OIS carrier and has an AF coil wound on the outside corresponding to the magnet and is position-adjustable in the direction of the optical axis; A lens module mounted on the AF carrier; A driving unit that moves the AF carrier in the direction of the optical axis and, when the OIS carrier is eccentric, moves the OIS carrier to align the center of the lens module with the center of the housing optical path; An AF displacement detection unit that operates when the AF carrier moves to obtain displacement information of the AF carrier; A camera control unit that receives displacement information from the AF displacement detection unit and controls the driving unit based on the received information, AF carrier feedback control type camera module.

2. In paragraph 1, The above driving part, An external FPCB that surrounds the housing and has a terminal on one side, A pair of X-drive coils that are fixedly connected to the external FPCB and correspond one-to-one to some magnets, and are installed on opposite sides with the OIS carrier in between, It includes a pair of Y drive coils that are fixedly connected to the external FPCB and correspond one-to-one to the remaining magnets, and are installed on opposite sides with the OIS carrier in between. AF carrier feedback control type camera module.

3. In paragraph 2, The above AF displacement detection unit is, It is mounted on the AF carrier and has an internal sensor that detects the movement of the AF carrier and an internal IC chip that is connected to the internal sensor. Equipped with an internal FPCB that surrounds the AF carrier and is connected to the internal IC chip. AF carrier feedback control type camera module.

4. In paragraph 3, As a means of connecting the internal FPCB and the external FPCB, An elastic connector that is connected to the AF coil and internal FPCB and can be elastically deformed, Including an FPCB spring that connects the elastic connector and the external FPCB. AF carrier feedback control type camera module.

5. In paragraph 4, The above elastic connector, Terminal connection part connected to the AF coil and internal FPCB, A spring connection that is connected to the FPCB spring, Connecting the terminal connection part and the spring connection part, and having an extension part that can be elastically deformed according to the movement of the AF carrier. AF carrier feedback control type camera module.

6. In paragraph 5, The above FPCB spring; A first connecting portion connected to the above spring connecting portion, A second connection part that connects to an external FPCB, A first connecting portion and a second connecting portion are connected, and include a bending portion having a bent shape and being elastically deformable. AF carrier feedback control type camera module.

7. In paragraph 6, The above external FPCB has a connection tab formed therein that is fixed to the second connection portion in a folded state. AF carrier feedback control type camera module.

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