Abstract:
The invention relates to a camera module package including a lens barrel having at least one lens therein and an IR filter installed at a lower end thereof. The package also includes a housing having the lens barrel disposed movable in an optical axis direction in an inner hole thereof. The package additionally includes a ceramic substrate attached to a lower end of the housing, the ceramic substrate having an opening formed on an upper surface thereof corresponding to the position of the lens. The package further includes an image sensor electrically connected to a lower part of the ceramic substrate, the image sensor having an image sensing region thereof exposed through the opening of the ceramic substrate. This prevents damaging the components by the adhesive leaking during the assembly, defective products due to infiltration of extraneous material, improves product reliability and reduces manufacturing costs.

Description:
[0001]    This application claims the benefit of Korean Patent Application No. 2005-0130422 filed on Dec. 27, 2005, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a camera module package, and more particularly, to a camera module package which simplifies an assembly process with a fewer components therein, prevents infiltration of extraneous material to obviate defective images and obtain superior quality images, and achieves miniaturization with reduced volume. 
         [0004]    2. Description of the Related Art 
         [0005]    Currently, a number of mobile terminal manufacturers are developing and mass-producing mobile terminals with camera module packages. Such camera module packages mounted inside the mobile terminals are developed in various forms according to the components and packaging methods. 
         [0006]    In general, a cameral module package can be classified mainly into Chip on Film (COF), Chip on Board (COBB), Chip Scale Package (CSP). And the current trend is to develop the camera module packages with focuses on high pixel, multi-function, miniaturization and low costs. 
         [0007]    Among the above types, the COB using a wire-bonding method adopts a process similar to the existing production process of the semiconductor and thus has high productivity compared to other packaging methods. But since an image sensor and a substrate is electrically connected via the wires, the COB requires an additional space with a large overall package size and is limited in the number of circuits processed. 
         [0008]    The flip-chip type COF does not require a separate space for connecting both ends of the wire to the image sensor and the substrate, thus reducing the area of the package to achieve miniaturization. Further, it can reduce the height of the barrel to miniaturize the package, uses a thin film or ductile PCB as the substrate to obtain a package reliable to external impacts, and involves a relatively simple process. In addition to the miniaturization of the package, signals can be processed quickly due to the smaller package size, less resistance, high density and multi-function. 
         [0009]    In the meantime, the CSP, which is the most effective way to miniaturize the package, has limitations as an image sensor, such as costly and prolonged manufacturing processes. 
         [0010]      FIG. 1  is a block diagram illustrating a conventional camera module package and  FIG. 2  is a sectional view illustrating the conventional camera module package. As shown, the camera module package  1  includes a lens barrel  10 , a housing  20 , a Flexible Printed Circuit Board (FPCB)  30  and an image sensor  40 . 
         [0011]    The lens barrel  10  is a hollow cylinder having a lens (not shown) therein. The lens barrel  10  has male threads  11  formed on an outer surface thereof and a cap  13  assembled to an upper end thereof. 
         [0012]    There may be at least one lens provided in the lens barrel  11 , and the number of the lens may vary according to the function and capacity of the camera module package desired to be realized. 
         [0013]    The housing  20  has an inner hole for receiving the lens barrel  10 , and has female threads  21  formed on an inner circumferential surface to be engaged with the male threads  11  of the lens barrel  10 . The housing  20  also has an IR filter  25  for filtering the light passed through the lens. 
         [0014]    With the above configuration, the lens barrel  10  is assembled into the female threads  21  of the housing, disposed movable in an optical axis direction with respect to the housing  20  fixed in its position. 
         [0015]    The FPCB  30  is bonded to a lower part of the housing  20 , having an opening formed at an end thereof to expose an image forming region of the image sensor  40  where the image of an object passed through the lens is formed. The FPCB  30  also has at least one passive element  39  mounted on an upper surface thereof. 
         [0016]    Further, the FPCB  30  has a connector  35  at the other end thereof to be connected to a corresponding connector (not shown) so as to be connected to a display means (not shown). 
         [0017]    A liquid polymer adhesive  36  is applied along a rectangular frame on the FPCB  30 , corresponding to the plurality of stud bumps  41  formed on an upper surface of the image sensor  40 . Then, the image sensor  40  is flip-chip bonded to the FPCB  30  via hot pressing the image sensor  40  to a lower surface of the FPCB  30  in order to align the image forming region and the opening  34 . 
         [0018]    This allows conductive particles between the corresponding terminals of the FPCB  30  and the image sensor  40  to be connected to each other in a single direction of conductivity, thereby electrically and mechanically connecting the terminals. 
         [0019]    However, as the FPCB  30  and the image sensor  40  are bonded by applying the liquid polymer adhesive and hot pressing, the manufacturing process is complicated and cumbersome. 
         [0020]    In addition, in the case where extraneous material infiltrates the IR filter  25  of the housing  20  mounted on the FPCB  30  or in the image sensor  40 , it is difficult to clean the image sensor  40  to eliminate the extraneous material, degrading the image quality of the camera module. 
         [0021]    Moreover, a separate connector  35  is provided and assembled to the other end of the FPCB  30 , increasing the number of components while limiting the volume reduction of the package. 
       SUMMARY OF THE INVENTION 
       [0022]    The present invention has been made to solve the foregoing problems of the prior art and therefore an object of certain embodiments of the present invention is to provide a camera module package which simplifies an assembly process with a fewer number of components therein, prevents infiltration of foreign material to obtain superior quality images, and achieves miniaturization with reduced volume. 
         [0023]    According to an aspect of the invention for realizing the object, there is provided a camera module package including: a lens barrel having at least one lens therein and an IR filter installed at a lower end thereof; a housing having the lens barrel disposed movable in an optical axis direction in an inner hole thereof; a ceramic substrate attached to a lower end of the housing, the ceramic substrate having an opening formed on an upper surface thereof corresponding to the position of the lens; and an image sensor electrically connected to a lower part of the ceramic substrate, the image sensor having an image sensing region thereof exposed through the opening of the ceramic substrate. 
         [0024]    Preferably, the ceramic substrate has a plurality of external connection terminals formed on an outer surface thereof. 
         [0025]    Preferably, the ceramic substrate has at least one passive elements mounted on an upper surface thereof. 
         [0026]    Preferably, the ceramic substrate has at least one passive element embedded in inner ceramic layers thereof. 
         [0027]    Preferably, the ceramic substrate has fixing grooves at an outer periphery of an upper surface thereof for receiving protrusions protruded from a lower end of the housing. 
         [0028]    Preferably, the ceramic substrate has a sensor receiving part formed on a lower surface thereof for receiving the image sensor, and the sensor receiving part has connection terminals corresponding to stud bumps formed on the image sensor. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0029]    The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: 
           [0030]      FIG. 1  is a block diagram illustrating a general camera module package; 
           [0031]      FIG. 2  is a sectional view illustrating the general camera module package; 
           [0032]      FIG. 3  is an exploded perspective view illustrating a camera module package according to the present invention; and 
           [0033]      FIG. 4  is a sectional view illustrating the camera module package according to the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0034]    Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. 
         [0035]      FIG. 3  is an exploded perspective view illustrating a camera module package according to the present invention, and  FIG. 4  is a sectional view illustrating the camera module package according to the present invention. 
         [0036]    As shown in  FIGS. 3 and 4 , the camera module package  100  includes a lens barrel  110 , a housing  120 , a substrate  130  and an image sensor  140 . 
         [0037]    The lens barrel  110  has a cylindrical shape and has a predetermined dimension of inner space where at least one lens  112  is disposed along an optical axis. 
         [0038]    The plurality of lenses  112  disposed in the lens barrel  110  may be spaced apart from another lens in a predetermined interval by a spacer  119 . 
         [0039]    The lens barrel  110  has male threads  111  formed on an outer surface thereof and a cap  113  assembled atop. The cap  113  has a light incident hole  113  a perforated in a center thereof and serves to fix the lenses  112  received in the lens barrel  110  in a fixed position. 
         [0040]    In addition, the lens barrel  110  has an IR filter  115  bonded by an adhesive to a lower end thereof for filtering the light passed through the lens barrel  110  with the lenses  112  therein. 
         [0041]    Here, the IR filter  115  may be provided on a lower end of the lens barrel  110  but is not limited thereto. The IR filter may also be bonded by an adhesive to a step formed at a lower periphery of an inner hole or the inner space of the lens barrel  110  in which the lenses  112  are disposed. 
         [0042]    In addition, the housing  120  has female threads formed on an inner circumferential surface of the inner hole thereof to be engaged with the male threads  111  of the lens barrel  110  so that the lens barrel  110  is received in the housing  120 . 
         [0043]    With the above configuration, the lens barrel  110  with the lenses  112  and the IR filter  115 , is capable of moving along the optical axis with respect to the housing  120  fixed by the thread engagement of the male threads  111  and the female threads  121 , and also the IR filter  115 , along with the lens barrel  110 , is detachable from the housing  120 . 
         [0044]    Meanwhile, the housing  120  has fixing protrusions  128  protruded from a lower surface thereof, corresponding to the fixing grooves  138  formed on the substrate  130  in order to facilitate the assembly of the housing  120  and the substrate  130  and align the center of the opening  134  of the substrate  130  with the optical axis of the lens barrel  110 , thereby locating the housing on the substrate. 
         [0045]    In addition, the ceramic substrate  130  has a lower end of the housing  120  with the lens barrel  110  assembled therein mounted on an upper surface thereof, and has the opening  134  formed on an upper surface thereof, corresponding to the lens  112  inside the lens barrel  110 . 
         [0046]    The ceramic substrate  130  has the fixing grooves  138  formed in an outer periphery of an upper surface thereof for receiving the fixing protrusions  128  protruded from a lower end of the housing  120 . 
         [0047]    The ceramic substrate  130  has a sensor receiving part  135  formed on a lower surface thereof for housing the image sensor  140 , and the sensor receiving part  135  has connection terminals  136  corresponding to stud bumps  141  of the image sensor  140 . 
         [0048]    Here, it is preferable that the connection terminals  136  of the ceramic substrate  130  is made of tin or tin alloy-based plating material so as to be connected to the stud bumps of the image sensor  140  via hot pressing or ultrasonic bonding. 
         [0049]    This allows omitting the conventional process of applying non-conductive liquid polymer adhesive  36  to a bonding region along a rectangular frame, corresponding to the stud bumps  141  of the image sensor  140  in order to bond the FPCB with the image sensor, simplifying the manufacturing process of the package. 
         [0050]    In addition, at least one passive element such as a capacitor and a resistor can be provided on an upper surface of the ceramic substrate  130  composed of at least two ceramic sheets  131  and  1132  stacked so as to reduce electric noise. Also, the passive elements may be embedded between the ceramic sheets  131  and  132 , in the form of an internal electrode pattern functioning as a resistor and capacitor. 
         [0051]    In addition, the ceramic substrate  130  has a plurality of external connection terminals  137  on an outer surface thereof so as to be connected to a socket (not shown) of a main board electrically connected to a display means (not shown). Thus, there is no need to provide a separate connector  35  at the other end of the image sensor as in the prior art, simplifying the configuration of the substrate and reducing the total volume of the substrate  130 . 
         [0052]    Meanwhile, the image sensor  140  has an image forming region formed in a central portion of an upper surface thereof, exposed through the opening  134  of the ceramic substrate  130 . The image sensor  140  is provided in the sensor receiving part  135  of the ceramic substrate  130 , positioned to be connected to the connection terminals  136  of the ceramic substrate  130 . 
         [0053]    The stud bumps of the image sensor  140  corresponding to the connection terminals  136  is made of tin or gold-based plating material so as to be bonded and electrically connected to the connection terminals  136  with high adhesive strength via hot pressing or ultrasonic bonding. 
         [0054]    Here, a filler may be filled between the outer periphery of the image sensor  140  and the inner surface of the sensor receiving part  135  to further increase the bonding strength between the image sensor  140  and the ceramic substrate  130 . 
         [0055]    In the above described manufacturing process of the camera module  100 , the lens barrel  110  having at least one lens  112  therein and an IR filter  115  mounted at a lower end thereof and the housing  120  with the female threads  121  formed on an inner surface thereof corresponding to the male threads  111  of the lens barrel  110  are prepared respectively and threadly engaged with each other so as to allow movement in the optical axis direction. 
         [0056]    Here, the IR filter  115  of transparent medium is bonded to a lower end of the lens barrel  110  by an adhesive, perpendicular to the optical axis of the lens barrel  110 . 
         [0057]    In addition, with the housing  120  assembled with the lens barrel  110  placed on an upper part of the ceramic substrate  130  composed of at least two layers of ceramic sheets  131  and  132  stacked, the fixing protrusions  128  protruded from a lower end of the housing  120  are assembled one-to-one with the fixing grooves  138  formed on an outer periphery of an upper surface of the ceramic substrate  130 , thereby locating the housing on the ceramic substrate  130 . 
         [0058]    At the same time, the adhesive is applied between a lower end of the housing  120  and an upper surface of the ceramic substrate  130 , thereby mounting the housing  120  perpendicular to the ceramic substrate  130 . 
         [0059]    Here, as the fixing grooves  138  are perforated in an uppermost ceramic sheet stacked on a lower ceramic sheet, the adhesive is prevented from permeating into the ceramic substrate while the housing  120  and the ceramic substrate  130  are bonded to each other. 
         [0060]    Subsequently, the image sensor  140  is disposed in the sensor receiving part  135  of the ceramic substrate  130  with the housing  120  mounted thereon, and the stud bumps  141  of the image sensor  140  are connected to the connection terminals  136  of the sensor receiving part  135 . 
         [0061]    At this time, a predetermined pressing force is applied to a contact surface between the connection terminals  136  and the stud bumps  141  with a source of heat provided, thereby bonding the two via hot pressing or ultrasonic bonding by applying ultrasonic waves. 
         [0062]    Here, the image forming region of the image sensor  140  is exposed through the opening  134  formed through the ceramic substrate  130 , in alignment with the optical axis of the lens barrel  110 . 
         [0063]    Here, the opening  134  and the sensor receiving part  135  of the ceramic substrate  130  are formed by stacking a plurality of ceramic sheets in a rectangular frame shape. It is preferable that the sensor receiving part  135  is formed in such a depth that the bottom of the image sensor  130  disposed in the sensor receiving part  135  is not protruded more than the lower edge of the ceramic substrate  130 . 
         [0064]    In the meantime, as the ceramic substrate  130  with the housing  120  and the image sensor  140  is inserted into a socket (not shown) of a main board electrically connected to a display means by pressing down directly, the external connection terminals  137  formed on an outer surface of the ceramic substrate  130  are easily assembled and electrically connected with the terminals parts of the socket. 
         [0065]    In addition, in the case where extraneous material infiltrates the upper surface, i.e., the image forming region of the image sensor  140 , the lens barrel  110  with the IR filter  115  can be separated from the housing  120 , exposing the image sensor  140  through the opening of the housing  120 . This allows cleaning the image sensor  140  to easily remove the extraneous material. 
         [0066]    According to the present invention set forth above, the housing threadly engaged with the lens barrel including the IR filter attached at a lower end thereof is mounted on the ceramic substrate, and the image sensor is provided on a lower part of the ceramic substrate with its image forming region exposed. This allows directly bonding the terminals via hot pressing and ultrasonic bonding without applying a liquid polymer adhesive between the substrate and the image sensor as in the prior art, thereby simplifying the manufacturing process and improving productivity. 
         [0067]    In addition, the lens barrel with the IR filter is detached from the housing to easily eliminate extraneous material infiltrating the image forming region of the image sensor, thereby preventing defective images and obtaining superior quality images. 
         [0068]    Further, the external connection terminals provided at an outer surface of the ceramic substrate is directly connected to the socket of the main board, without requiring components such as the connector in the prior art, thereby reducing the manufacturing costs and volume of the package. 
         [0069]    While the present invention has been shown and described in connection with the preferred embodiments, it will be apparent to those skilled in the art that modifications and variations can be made without departing from the spirit and scope of the invention as defined by the appended claims.