Abstract:
An image sensor package structure is proposed, in which the electric connection of an image sensing chip and the assembly of a housing and a lens barrel are separately carried out to avoid restriction in the packaging process and influence of outside contaminants. Moreover, corresponding faces of the housing and the lens barrel are designed to be smooth surfaces to reduce the probability of adhesion and accumulation of outside contaminants, thereby enhancing the process yield and also reducing the process cost.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to an image sensor package structure and, more particularly, to an image sensor package structure capable of enhancing the production yield.  
         [0003]     2. Description of Related Art  
         [0004]     As shown in  FIG. 1  in a conventional image sensor package structure, flange layer  11  and a cavity  12  are formed on an injection molded housing  10 . An image sensing chip  13  is then placed in the cavity  12 . The flange layer is of an inner transparent layer  14  is placed on the cavity  12 . The flange layer is of an inner thread type to match a lens barrel  15  with an outer thread. The lens barrel  15  includes a through hole  16 , an aspheric lens  17 , and an IR-cut filtering lens  18 . Besides, a sealant  19  is used in the cavity  12  and covers the image sensing chip  13 .  
         [0005]     In the above conventional package structure, the surface mount technology (SMT) is utilized to achieve electric connections of a printed circuit board during the production process. Generally speaking, the SMT process is performed in environments with temperature above 200° C. to make electric connections. Because most today&#39;s lenses are plastic lenses that cannot tolerate such high temperatures, if the lens barrel  15  is installed on the housing  10  before performing the SMT process, the plastic lens may deform in the high temperature environment to cause problems in optical imaging.  
         [0006]     Therefore, it is necessary to install the lens barrel  15  after the SMT process. The SMT process, however, is not performed in a clean room. That is, the prior art needs to make use of the cleaning process to remove particle contaminants produced in the SMT process. It is very difficult to clean particle contaminants of the housing  15  having the flange layer  11  with an inner thread. The process yield and quality are thus badly affected.  
       SUMMARY OF THE INVENTION  
       [0007]     An object of the present invention is to provide an image sensor package structure, in which the housing and the lens barrel are assembled in a non-thread way, and particle contaminants produced in the SMT process can be avoided, thereby enhancing the process yield and generally solving the problems in the prior art.  
         [0008]     Another object of the present invention is to provide an image sensor package structure manufactured in a two-state packaging way so as to avoid various restrictions occurring in the conventional production process.  
         [0009]     To achieve the above objects, an image sensor package structure of the present invention comprises a substrate, a shaped body, an image sensing chip, a housing, and a lens barrel. A plurality of metallization traces is disposed on the surface of the substrate. The shaped body is installed on the substrate and forms a cavity. The image sensing chip is installed in the cavity and electrically connected to the substrate via the metallization traces. A lens and a through hole are disposed at the central line of the lens barrel. The lens can receive light from a light source via the through hole. The housing is a hollow body with two open ends, and can be installed above or enclose the shaped body. The lens barrel is movably sleeved in the housing. The housing is used to protect and guide or assist in guiding the lens barrel to make relative motion with respect to the image sensing chip for optical imaging. The inner surface of the housing and the outer surface of the lens barrel are corresponding smooth surfaces to avoid adhesion and accumulation of outside contaminants during the manufacturing process. Because the assembly of the lens barrel and the housing and the electric connections of the image sensing chip can be separately performed, the production process is easier, and the probability that the image sensing chip is contaminated by outside contaminants can be reduced.  
         [0010]     The present invention also provides another image sensor package structure, which comprises a shaped body, an image sensing chip, a housing, and a lens barrel. A plurality of metallization traces are directly disposed on the surface of the shaped body. The shaped body has a cavity to receive the image sensing chip. The image sensing ship is electrically connected to the shaped body via the metallization traces. A lens and a through hole are disposed at the central line of the lens barrel. The lens can receive light from a light source via the through hole. The housing is a hollow body with two open ends, and can be installed above or enclose the shaped body. The lens barrel is movably sleeved in the housing. The housing is used to protect and guide or assist in guiding the lens barrel to make relative motion with respect to the image sensing chip for optical imaging. The inner surface of the housing and the outer surface of the lens barrel are corresponding smooth surfaces to avoid adhesion and accumulation of outside contaminants during the manufacturing process. Because the assembly of the lens barrel and the housing and the electric connections of the image sensing chip can be separately performed, the production process is easier, and the probability that the image sensing chip is contaminated by outside contaminants can be reduced. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]     The various objects and advantages of the present invention will be more readily understood from the following detailed description when read in conjunction with the appended drawings, in which:  
         [0012]      FIG. 1  is a diagram of a conventional image sensor package structure;  
         [0013]      FIG. 2  is a diagram of an image sensor package structure according to a first embodiment of the present invention:  
         [0014]      FIG. 3  is a diagram of an image sensor package structure according to a second embodiment of the present invention:  
         [0015]      FIG. 4  is a diagram of an image sensor package structure according to a third embodiment of the present invention; and  
         [0016]      FIG. 5  is a diagram of an image sensor package structure according to a fourth embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0017]     As shown in  FIG. 2 , the present invention provides an image sensor package structure, which comprises a substrate  100 , a shaped body  110 , an image sensing chip  120 , a housing  130 , and a lens barrel  140 . A plurality of metallization traces  101  is disposed on the surface of the substrate  100 . The shaped body  110  is installed on the substrate  100  and forms a cavity  111 . The image sensing chip  120  is installed in the cavity  111  and electrically connected to the substrate  100  via the metallization traces  101 . The lens barrel  140  includes a lens  141  and a through hole  142 . The through hole  142  penetrates through the central line of the lens barrel  140 , and is unobstructed to a light source so that the lens  141  can receive light from the light source via the through hole  142  to focus and transmit light to the image sensing chip  120 . The housing  130  is a hollow body with two open ends, and is installed above the shaped body  110 . The lens barrel  140  is movably sleeved in the housing  130 . The housing  130  is used to protect and guide or assist in guiding the lens barrel  140  to make relative motion with respect to the image sensing chip  120  for optical imaging. The lens barrel  140  is a cylinder. The inner surface of the housing  130  and the outer surface of the lens barrel  140  are corresponding smooth surfaces to avoid adhesion and accumulation of outside contaminants during the manufacturing process. The so-called smooth surfaces means the edges  137  and  147  are continuous surfaces instead of threaded surfaces with acute bend angles in the cross-section view. Therefore, the probability of adhesion and accumulation of outside contaminants can be reduced. In addition to the cylindrical shape, the lens barrel  140  can also be of any coned shape.  
         [0018]     The packaging of the image sensor package structure according to this embodiment of the present invention can be performed in two stages. In the first stage, electric connection between the image sensing chip  120  and the substrate  100  is performed. In the second stage, the housing  130  and the lens barrel  140  are assembled above the image sensing chip  120 . The second stage is proceeded only after it is confirmed that there is no outside contaminants in the first stage. The situation of outside particle contamination after the whole packaging process can thus be avoided, hence enhancing the process yield.  
         [0019]     The image sensing chip  120  in this embodiment is fabricated by means of flip chip to reduce the required bonding area of bonding wire so as to accomplish a miniaturized package.  
         [0020]     In this embodiment, a back cover layer  150  can further be placed in the cavity  111  of the shaped body  110  to cover the image sensing chip  120  so as to prevent outside particles from contaminating the image sensing chip  120 . Moreover, A light transparent layer  160  can be provided above the image sensing chip  120 . This light transparent layer  160  can be an IR-cut filtering lens. A light filtering layer  170  can also be provided at the bottom end of the lens barrel  140 . The light filtering layer  170  can also be an IR-cut filtering lens.  
         [0021]     In the above embodiment, the housing  130  is placed above the image sensing chip  120 . According to the second embodiment of the present invention, a housing  230  is sleeved around a shaped body  210  to enclose the image sensing chip  220 , as shown in  FIG. 3 .  
         [0022]     In the above two embodiments, the image sensing chip is electrically connected to the substrate. In practice, the substrate call be excluded. According to the third embodiment of the present invention shown in  FIG. 4 , an image sensor package structure comprises a shaped body  310 . The image sensing chip  320 , a housing  330 , and a lens barrel  340 . A plurality of metallization traces  311  is disposed on the surface of the shaped body  310 . The shaped body  310  has a cavity  312 . The image sensing chip  320  is installed in the cavity  312  and electrically connected to the shaped body  310  via the metallization traces  311 . The lens barrel  340  includes a lens  341  and a through hole  342 . The through hole  342  penetrates through the central line of the lens barrel  340 , and is unobstructed to a light source so that the lens  341  can receive light from the light source via the through hole  342  to focus and transmit light to the image sensing chip  320 . The housing  330  is a hollow body with two open ends, and is installed above the shaped body  310 . The lens barrel  340  is movably sleeved in the housing  330 . The housing  330  is used to protect and guide or assist in guiding the lens barrel  340  to make relative motion with respect to the image sensing chip  320  for optical imaging. The inner surface of the housing  330  and the outer surface of the lens barrel  340  are corresponding smooth surfaces to avoid adhesion and accumulation of outside contaminants during the manufacturing process.  
         [0023]     A back cover  350  can further be placed below the image sensing chip  320  to avoid contamination of the image sensing chip  320 . Moreover, A light transparent layer  360  can be provided above the image sensing chip  320 . A light filtering layer  370  can also be provided at the bottom end of the lens barrel  340 . The light transparent layer  360  and the light filtering layer  370  can be an IR-cut filtering lenses.  
         [0024]     According to the fourth embodiment of the present invention shown in  FIG. 5 , a housing  430  is sleeved around a shaped body  410  to enclose the image sensing chip  420 .  
         [0025]     To sum it up, the image sensor package structure of the present invention can be manufactured by means of two-stage packaging to prevent not easy cleaning and unwanted particle sources from affecting the process yield and quality. Moreover, the housing and the lens barrel can be assembled in a non-thread way to further reduce the probability of contamination. Besides, the present invention manufactures an image sensing chip by means of flip chip to enhance the feasibility of miniaturized package.  
         [0026]     Although the present invention has been described with reference to the preferred embodiment thereof, it will be understood that the invention is not limited to the details thereof. Various substitutions and modifications have been suggested in the foregoing description, and other will occur to those of ordinary skill in the art. Therefore, all such substitutions and modifications are intended to be embraced within the scope of the invention as defined in the appended claims.