JP2014093632A - Camera module manufacturing method, camera module, and portable terminal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a low-profile camera module capable of high-precision positioning between an image pickup lens and an image pickup element even when a circuit board has a warp and capable of forming a high-quality image, a camera module manufactured by the method, and a portable terminal using the camera module.SOLUTION: Since an image pickup element 11 and a pedestal member 17 are positioned with each other on the basis of two protrusions 22, 23 of a jig 20, the accuracy of a circuit board 16 becomes irrelevant, so that by placing an image pickup lens unit LS on the pedestal member 17 with high accuracy, it is possible to realize positioning between the image pickup lens unit LS and the image pickup element 11 with high accuracy.

Description

  The present invention relates to a method for manufacturing a small camera module using an image sensor such as a CCD image sensor or a CMOS image sensor, a camera module manufactured by the method, and a portable terminal using the camera module.

  In recent years, as mobile terminals equipped with camera modules using solid-state image sensors such as CCD (Charge Coupled Device) type image sensors or CMOS (Complementary Metal Oxide Semiconductor) type image sensors have increased in popularity, higher-quality images have been developed. In order to obtain the above, those equipped with a camera module using an image sensor with a large number of pixels have been supplied to the market.

  In particular, when an image sensor with a large number of pixels is used, a high-quality image cannot be obtained unless the imaging lens and the image sensor are positioned with high accuracy. Patent Document 1 discloses a technique for positioning the imaging lens and the imaging element by bringing the lower end of a pedestal member on which the imaging lens is mounted on the upper surface of the imaging element.

JP 2011-237633 A

  However, in the case of the camera module of Patent Document 1, when pressing or assembling or when a mobile terminal equipped with the camera module receives an impact due to dropping or the like, a strong pressing force or impact is applied to the image sensor via the base member. A force is applied, which may damage the image sensor. On the other hand, if the pedestal member is brought into contact with the circuit board on which the imaging device is mounted and the imaging lens and the imaging device are positioned, damage to the imaging device can be avoided.

  By the way, recently, a thin portable terminal called a smartphone has been developed and gained high popularity. The camera module mounted on such a smartphone must have a lower profile (shorter overall length in the optical axis direction) than the conventional one from the viewpoint of design while maintaining the function of forming high-quality images. Is desired.

  In order to reduce the height of the camera module, there is an attempt to reduce the thickness of the circuit board to which the image sensor is attached. However, as the thickness of the circuit board is reduced, its rigidity is lowered and a phenomenon such as warpage is likely to occur. When the circuit board is warped, the parallelism between the circuit board and the image sensor and the positional relationship between the circuit board and the base member become unstable when the base member is brought into contact with the circuit board, and the optical axis of the imaging lens is imaged. There is a risk that a so-called tilt or the like that is tilted with respect to the light receiving surface of the element may occur, thereby making it impossible to form a high-quality image.

  The present invention has been made in view of such problems, and even when the circuit board is warped, the imaging lens and the imaging element can be positioned with high accuracy, and a high-quality image can be formed. An object of the present invention is to provide a method for manufacturing a low-profile camera module, a camera module manufactured by the method, and a portable terminal using the camera module.

The manufacturing method of the camera module according to claim 1,
An imaging lens unit including an imaging lens for forming a subject image;
An image sensor that photoelectrically converts a subject image formed by the imaging lens;
In a manufacturing method of a camera module having a circuit board on which the imaging element is mounted,
Using a jig having a plurality of first protrusions formed on a flat plate higher than the thickness of the circuit board and a plurality of second protrusions formed lower than the thickness of the circuit board,
A circuit board having a first through hole and a second through hole formed at a position corresponding to the second convex portion at a position corresponding to the first convex portion, and the first convex portion as the first convex portion. Inserting the second convex portion into the second through hole and placing the second convex portion on the flat plate;
Placing the imaging device on the first convex portion, and bonding and fixing the imaging device to the circuit board;
Electrically connecting the connection terminal of the image sensor and the connection terminal of the circuit board;
A leg member formed to be insertable into the second through hole and a pedestal member having a side wall formed so as to cover the imaging element are brought into contact with the tip of the leg and the tip of the second convex part. Inserting and placing the leg portion in the second through-hole,
A step of bonding and fixing the side wall portion to the circuit board.

  According to the present invention, first, the image pickup device is placed on the first convex portion of the jig inserted into the first through hole of the circuit board, and the image pickup device is bonded and fixed to the circuit board. The image sensor is positioned with respect to the tool, and the leg is inserted into the second through-hole so that the tip of the leg formed so as to be insertable into the second through-hole and the tip of the second convex part abut. Thus, by positioning the pedestal member with respect to the jig, the imaging element and the pedestal member are positioned relative to each other with reference to the two convex portions of the jig. Thereby, the accuracy (flatness) of the circuit board is irrelevant to the positioning of the pedestal member and the imaging element, and even if the circuit board is warped by accurately arranging the imaging lens unit on the pedestal member, High-accuracy positioning can be performed so that the optical axis of the imaging lens unit is orthogonal to the light receiving surface of the imaging device.

  According to a second aspect of the present invention, there is provided a camera module manufacturing method according to the first aspect, wherein a through-hole is formed in the first convex portion, and the imaging element is disposed on the first convex portion. When it is placed, suction is performed using the through-hole.

  Thereby, an image pick-up element can be stuck on a plurality of 1st convex parts, and the parallelism of the field formed by a plurality of 1st convex parts and the light-receiving surface of an image sensor can be raised more. As a result, the light receiving surface of the image sensor can be accurately positioned with respect to the image pickup lens unit.

  According to a third aspect of the present invention, there is provided the camera module manufacturing method according to the first or second aspect, wherein the leg portion is formed outside the side wall portion.

  By providing the second through-hole through which the leg is inserted outside the side wall, there is no risk of entry of dust, etc., even when the jig is removed, and it is possible to prevent entry of dust into the second through-hole. Therefore, a hole blocking process is not required.

  According to a fourth aspect of the present invention, there is provided the camera module manufacturing method according to any one of the first to third aspects, wherein the imaging lens unit and the pedestal member are integrally or integrally formed in advance. And

  Thus, if the imaging lens unit and the pedestal member are previously positioned and assembled in separate processes, the pedestal member can be pressed against the jig by utilizing the weight of the imaging lens unit. Accuracy can be increased. Note that “integral” means that the pedestal member is a part of the imaging lens unit, and “integrally” means that the pedestal member is formed as a separate member from the imaging lens unit and is bonded or the like It means being connected.

  The camera module manufacturing method according to claim 5 is the invention according to any one of claims 1 to 4, wherein the adhesive used in the step of bonding and fixing the imaging element to the circuit board is a UV curable type. It is characterized by.

  The UV curable adhesive generally has a high curing speed, and it is used for bonding to contribute to shortening of the manufacturing time. Moreover, since it can harden instantaneously at the process of mounting a base member, the shift | offset | difference of a base member and a jig | tool at the time of conveyance in a process can be prevented.

  A camera module according to a sixth aspect is manufactured by the manufacturing method according to any one of the first to fifth aspects.

  A portable terminal according to a seventh aspect includes the camera module according to the sixth aspect.

  According to the present invention, a method for manufacturing a low-profile camera module that can perform high-precision positioning between an imaging lens and an imaging element and form a high-quality image even if the circuit board is warped, and thereby A manufactured camera module and a portable terminal using the camera module can be provided.

It is sectional drawing along the optical axis of the camera module 10 concerning this Embodiment. It is sectional drawing which cut | disconnected the camera module 10 of FIG. 1 by the II-II line | wire, and looked at the arrow direction. 5 is a diagram illustrating a manufacturing process of the camera module 10. FIG. 5 is a diagram illustrating a manufacturing process of the camera module 10. FIG. It is sectional drawing along the optical axis of the camera module 10 concerning another embodiment. It is sectional drawing along the optical axis of the camera module 10 concerning another embodiment. It is the front view (a) of the smart phone which mounts a camera module, and the back view (b) of the smart phone which applied the camera module. It is a control block diagram of the smart phone of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of a camera module 10 according to the present embodiment. The cross-sectional view shown in FIG. 1 is a cross-section including the optical axis around the imaging lens 12, and the cross section taken below the pedestal member 17 along the line I-I shown in FIG. FIG. 2 is a cross-sectional view of the camera module 10 of FIG. 1 taken along the line II-II and viewed in the direction of the arrow. The following configuration is a schematic diagram, and some shapes, dimensions, and the like are different from actual ones.

  As shown in FIG. 1, the camera module 10 forms a subject image on a CMOS image sensor 11 as a solid-state image sensor provided with a photoelectric conversion unit (light receiving surface) 11 a and the photoelectric conversion unit 11 a of the image sensor 11. The imaging lens 12, the lens barrel 13 that holds the imaging lens 12, the parallel plate-like optical filter 14 configured by an IR cut filter and / or a low-pass filter, the actuator 15 that drives the imaging lens 12, and the imaging element 11 And a pedestal member 17 that holds the imaging lens 12 and the actuator 15. The imaging lens unit is constituted by the imaging lens 12, the lens barrel 13, and the actuator 15.

  As shown in FIG. 1, the imaging device 11 is an imaging surface in which pixels (photoelectric conversion devices) are two-dimensionally arranged on the light receiving side (upper surface in FIG. 1) on a parallel plate chip 11b. The photoelectric conversion unit 11a is formed, and a signal processing circuit (not shown) is formed around the photoelectric conversion unit 11a. Such a signal processing circuit includes a drive circuit unit that sequentially drives each pixel to obtain a signal charge, an A / D conversion unit that converts each signal charge into a digital signal, and a signal that forms an image signal output using the digital signal. It consists of a processing unit and the like.

  A plurality of pads (not shown) formed near the outer edge of the chip 11b of the image sensor 11 on the light receiving surface side are connected to the circuit board 16 by wires 11c. As shown in FIG. 2, the circuit board 16 has three first through holes 16a and three second through holes 16b. Here, the first through hole 16a is provided so as to contact the periphery of the image sensor 11. The diameter of the first through hole 16a is preferably larger than the diameter of the second through hole 16b. Since the circuit board 16 is thin, as shown in FIG. 1, it is assumed that both ends warp so as to be lifted by Δ when placed on a horizontal plane.

  The pedestal member 17 integrally formed of resin has a generally rectangular parallelepiped housing shape, and includes four side wall portions 17a provided so as to surround the image pickup device 11 and an upper wall portion 17b intersecting with the upper end thereof. Have. A rectangular opening 17c is formed at the center of the upper wall portion 17b, and the optical filter 14 is attached to the lower surface of the upper wall portion 17b so as to cover the opening 17c. Further, as shown in FIGS. 1 and 2, three leg portions 17 d extend from the lower surface of the upper wall portion 17 b downward so as to pass the outside of the image sensor 11.

  The imaging device 11 converts the signal charge from the photoelectric conversion unit 11a into an image signal such as a digital YUV signal, and an external circuit (not shown) (for example, a camera module) is connected from the wire 11c through the wiring pattern of the circuit board 16. To the control circuit of the higher-level device mounted). Further, it is also possible to receive power and a clock signal for driving the image pickup device 11 from an external circuit through the wire 11c from the wiring pattern of the circuit board 16. Here, Y is a luminance signal, U (= R−Y) is a color difference signal between red and the luminance signal, and V (= BY) is a color difference signal between blue and the luminance signal. Note that the image sensor is not limited to the above CMOS image sensor, and other devices such as a CCD may be used.

  In FIG. 1, an imaging lens 12 is provided inside a lens barrel 13. The actuator 15 includes a cylindrical carrier 15a fixed to the lens barrel 13, a coil 15b attached to the carrier 15a and extending in the direction of the optical axis, a magnet 15c disposed opposite to the coil 15b, and a magnet 15c. It consists of a supported housing-like yoke 15d. The coil 15b is connected to an external circuit via a wiring (not shown). The lower end of the yoke 15d is bonded onto the upper wall portion 17b of the base member 17. The carrier 15a is urged toward the image pickup device 11 by an elastic member (not shown). In FIG. 2, PT and NT are a positive terminal and a negative terminal for supplying power to the actuator 15, and are provided on the circuit board 16 outside the base member 17.

  Next, a method for manufacturing the camera module 10 will be described. 3 and 4 are diagrams showing the manufacturing process of the camera module 10, in which some components are simplified. At the time of manufacture, the jig 20 is first prepared. The metal jig 20 is formed lower than the flat plate 21, three hollow first protrusions 22 formed on the flat plate 21 higher than the thickness of the circuit board 16, and the thickness of the circuit board 16. And three second convex portions 23. The first convex portion 22 is formed corresponding to the first through hole 16a of the circuit board 16, and the second convex portion 23 is formed corresponding to the second through hole 16b. The first convex portion 22 is connected to a negative pressure pump (not shown) so as to suck the inside (through hole).

  As shown in FIG. 3 (a), the first convex portion 22 of the jig 20 is inserted into the first through hole 16a, and the second convex portion 23 is inserted into the second through hole 16b. The circuit board 16 is placed on the flat plate 21 of the tool 20. In this state, if the circuit board 16 is warped, a part that is in a floating state with respect to the flat plate 21 is generated.

  Next, as illustrated in FIG. 3B, the imaging element 11 is placed on the first convex portion 22 protruding upward from the first through hole 16 a. At this time, since the inside of the first convex portion 22 is sucked by a negative pressure pump (not shown), the image sensor 11 is in close contact with the tip of the first convex portion 22. In this state, the image sensor 11 is bonded and fixed to the circuit board 16. The adhesive may be applied in advance on the circuit board 16 on which the image pickup device 11 is placed, or may be applied in advance at a position avoiding the first convex portion 22 on the back surface of the image pickup device 11. Good.

  Thereafter, as shown in FIG. 3C, the pads (connection terminals) of the image sensor 11 and the circuit patterns (connection terminals) of the circuit board 16 are electrically connected by wires 11c.

  Further, as shown in FIG. 3 (d), the UV curable adhesive BD is applied from the dispenser DP onto the circuit board 16 at a position corresponding to the side wall portion 17 a of the base member 17.

  Thereafter, as shown in FIG. 3 (e), the base member 17 (with the optical filter 14 mounted) gripped by a robot (not shown) capable of posture control is brought close to the circuit board 16, and the leg portion 17d is moved to the first position. Then, the base member 17 is pressed toward the jig 20 after being inserted into the second through-hole 16b and having its tip abutted against the tip of the second convex portion 23. Thereby, the front-end | tip of the leg part 17d can closely_contact | adhere with the front-end | tip of the 2nd convex part 23, and it can avoid that there is backlash. The side wall portion 17a is formed in advance so as to be slightly separated from the upper surface even when the circuit board 16 is warped and in contact with the applied adhesive BD. The 2nd through-hole 16b exhibits the function of a guide when the front-end | tip of the leg part 17d contact | abuts to the front-end | tip of the 2nd convex part 23. FIG. Therefore, it is preferable that the upper surface side of the second through-hole 16b has a tapered diameter, or the tip of the leg portion 17d has a tapered shape.

  In this state, the side wall portion 17a of the pedestal member 17 is in contact with the UV curable adhesive BD on the circuit board 16. Therefore, when the UV curable adhesive BD is cured by irradiating UV light from the light source OS. The base member 17 is bonded and fixed to the circuit board 16. At this time, even if the circuit board 16 is warped, the pedestal member 17 is accurately positioned with respect to the imaging element 11 via the jig 20.

  That is, since the imaging element 11 and the base member 17 are positioned with respect to each other with respect to the two convex portions 22 and 23 of the jig 20, the accuracy of the circuit board 16 is irrelevant, and the imaging lens unit LS described later on the base member 17. With high accuracy, positioning of the imaging lens unit LS and the imaging device 11 can be realized with high accuracy even if the circuit board 16 is warped.

  Further, as shown in FIG. 4A, the actuator 15 (here, the imaging lens unit LS) is bonded and fixed to the pedestal member 17 together with the imaging lens 12 and the lens barrel 13. Note that the imaging lens unit LS may be integrated or integrated with the base member 17 in the step of FIG. Thereby, the base member 17 can be pressed against the jig 20 by utilizing the weight of the imaging lens unit LS.

  Thereafter, as shown in FIG. 4B, the jig 20 can be easily detached from the circuit board 16 by stopping the suction of the negative pressure pump. Here, in order to prevent dust from entering, the first through hole 16a and the second through hole 16b exposed on the back surface of the circuit board 16 are filled with the filler FT from the dispenser DP. Thus, the camera module 10 is completed.

  FIG. 5 is a cross-sectional view similar to FIG. 2 of a camera module 10 according to another embodiment. In this embodiment, four first through holes 16a and four second through holes 16b of the circuit board 16 are provided for each of the embodiments shown in FIG. The difference is that 20 first convex portions 22 and second convex portions 23 and four leg portions 17 d of the base member 17 are provided. Other configurations are the same as those of the above-described embodiment.

  FIG. 6 is a cross-sectional view similar to FIG. 2 of a camera module 10 according to another embodiment. In the present embodiment, four leg portions 17 d are arranged outside the side wall portion 17 a of the base member 17. In addition, the second protrusion 23 of the jig 20 and the second through hole 16b of the circuit board 16 are arranged at positions corresponding to this. Thus, by providing the 2nd through-hole 16b in which the leg part 17d is penetrated on the outer side of the side wall part 17a, the space in the base member 17 from the 2nd through-hole 16b in the state which removed the jig | tool 20. This eliminates the possibility of entering dust and the like, eliminating the need for filling the second through-hole 16b with the filler FT in the hole blocking step (see FIG. 4B) for preventing entry of dust and the like, and reducing the number of steps. it can.

  The operation of the camera module 10 described above will be described. FIG. 7 shows a state in which the camera module 10 is mounted on a smartphone 100 that is an example of a mobile terminal. FIG. 8 is a control block diagram of the smartphone 100.

  In the camera module 10, for example, the object-side end surface of the lens barrel 13 is provided on the back surface of the smartphone 100 (see FIG. 7B), and a liquid crystal display unit is disposed on the surface side of the smartphone 100.

  The camera module 10 is connected to the control unit 101 of the smartphone 100 via an external connection terminal (an arrow in FIG. 5), and outputs an image signal such as a luminance signal or a color difference signal to the control unit 101 side.

  On the other hand, as shown in FIG. 8, the smartphone 100 controls each unit in an integrated manner, and a control unit (CPU) 101 that executes a program corresponding to each process, a switch such as a power source, a number, and the like using a touch pad. An input unit 60 for inputting instructions, and a display unit 65 for displaying captured images and the like in addition to predetermined data on a liquid crystal panel (however, the touch panel 70 serves as both the liquid crystal panel of the display unit and the touch pad of the input unit) And a wireless communication unit 80 for realizing various information communications with an external server, and a storage unit (ROM) storing necessary data such as a system program, various processing programs, and a terminal ID of the smartphone 100 91, various processing programs and data executed by the control unit 101, processing data, or camera module 10. And a temporary storage unit used as a work area for temporarily storing the imaging data and the like and a (RAM) 92.

  The camera module 10 is operated by the operation of the input unit 60 of the smartphone 100. The camera module 10 is operated by driving the imaging lens 12 by the actuator 15 to perform an autofocus operation and pressing the release button 71 or the like. Imaging. The image signal input from the camera module 10 is stored in the storage unit 91 or the temporary storage unit 92 by the control system of the smartphone 100 or displayed on the display unit 65, and further via the wireless communication unit 80. It is transmitted to the outside as video information.

  The present invention is not limited to the embodiments described in the specification, and other embodiments and modifications are apparent to those skilled in the art from the embodiments and ideas described in the present specification. It is. For example, the adhesive that bonds the base member to the circuit board may be used in combination with a UV curable adhesive and a thermosetting adhesive in consideration of impact resistance.

DESCRIPTION OF SYMBOLS 10 Camera module 11 Image pick-up element 11a Photoelectric conversion part 11b Chip 11c Wire 12 Imaging lens 13 Lens tube 14 Optical filter 15 Actuator 15a Carrier 15b Coil 15c Magnet 15d Yoke 16 Circuit board 16a 1st through-hole 16b 2nd through-hole 17 Base Member 17a Side wall part 17b Upper wall part 17c Opening 17d Leg part 20 Jig 21 Flat plate 22 First convex part 23 Second convex part 60 Input key part 65 Display part 70 Touch panel 71 Release button 80 Wireless communication part 92 Storage part 100 Smartphone 101 Control unit / Example BD Curing adhesive DP Dispenser FT Filler LS Imaging lens unit OS Light source

Claims (7)

An imaging lens unit including an imaging lens for forming a subject image;
An image sensor that photoelectrically converts a subject image formed by the imaging lens;
In a manufacturing method of a camera module having a circuit board on which the imaging element is mounted,
Using a jig having a plurality of first protrusions formed on a flat plate higher than the thickness of the circuit board and a plurality of second protrusions formed lower than the thickness of the circuit board,
A circuit board having a first through hole and a second through hole formed at a position corresponding to the second convex portion at a position corresponding to the first convex portion, and the first convex portion as the first convex portion. Inserting the second convex portion into the second through hole and placing the second convex portion on the flat plate;
Placing the imaging device on the first convex portion, and bonding and fixing the imaging device to the circuit board;
Electrically connecting the connection terminal of the image sensor and the connection terminal of the circuit board;
A leg member formed to be insertable into the second through hole and a pedestal member having a side wall formed so as to cover the imaging element are brought into contact with the tip of the leg and the tip of the second convex part. Inserting and placing the leg portion in the second through-hole,
And a step of adhering and fixing the side wall portion to the circuit board.   2. A through hole is formed in the first convex portion, and suction is performed using the through hole when the imaging device is placed on the first convex portion. The manufacturing method of the camera module as described in any one of.   The method of manufacturing a camera module according to claim 1, wherein the leg portion is formed outside the side wall portion.   The method for manufacturing a camera module according to claim 1, wherein the imaging lens unit and the pedestal member are integrally or integrally formed in advance.   The method for manufacturing a camera module according to claim 1, wherein the adhesive used in the bonding and fixing step is a UV curable type.   A camera module manufactured by the manufacturing method according to claim 1.   A portable terminal comprising the camera module according to claim 6.

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