Abstract:
An image detecting module includes a socket, a circuit board, an image sensor, an elastic element, a filter and a holder. The socket comprises an inner circumference wall along a main axis for defining an inner space and a platform that extended from the inner circumference wall. Pluralities of mounting holes are provided on the holder and pluralities of protrusions are provided on the socket; thus the elastic element and the filter could be fixed between the platform and the holder by fitting the protrusions into the mounting holes.

Description:
This application is a continuation-in-part application of co-pending U.S. application Ser. No. 12/704,917, filed Feb. 12, 2010, the contents of which are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a lens module, and more particularly, to a lens module of digital camera formed with components such as the filter being fixed on a stand-alone socket using the holder. 
     2. Description of the Prior Art 
     Currently on the market, mobile phones (or cell phones) with photo-taking function, digital cameras, and video cameras are all deployed with a lens module. A lens module consists essentially of a lens group, a lens barrel, and an image sensor.  FIG. 1  is a views of lens module of the conventional prior art. The lens module consists of the lens group  81 , lens barrel  82 , and image sensor  83 . The lens group  81  are placed inside the lens barrel  82  and include a lens  811  used for focalization and a filter  812  for eliminating specific optical frequency. The image sensor  83  is equipped on one side of the lens barrel  82  and includes one transparent cover plate  831 , an image sensing chip  832 , and one base board  833 . 
     As shown in  FIG. 1 , the image sensing chip  832  is fixed on the base board  833  and further packaged between the transparent cover plate  831  and the base board  833  by using the transparent cover plate  831 . Thus, the optical image signal entering the lens barrel  82  is firstly focalized through the lenses  811 , is filtered by the filter  812 , and then passes through the transparent cover plate  831  to the image sensing chip  832 . The image sensing chip  832  further converts the optical image signal to the electronic image signal. 
     For the lens module described above, since an area  821  is to be provided by the lens barrel  82  for placing the filter  812  and the lens barrel  82  is made of plastic, it is easier for the assembly to occupy more space and become heavier. Hence, if the filter placement area  821  can be saved, the lens module can thus become thinner. 
     Referring to  FIG. 2 , which is a view of another lens module of the prior art. The lens module comprises a socket  91 , a lens unit  92  screwed into the socket  91 , an elastic element  93  inserted in the socket  91 , a filter  94  fixed inside the socket  91 , an image sensing chip  95 , and a circuit board  96 . This method of assembly allows the lens module to become thinner, but the filter  94  needs to be dispensed to be fixed on the socket  91  and thus the assembling process will be non-reversible. In the actual production process, the assembly may be re-processed because of the tilted optical axis. In the re-assembling process, the filter  94  dispensed and fixed on the socket  91  will be damaged and the cost is thus increased. 
     SUMMARY OF THE INVENTION 
     In view of the above, one object of the present invention is to provide a lens module in which the filter is placed on a stand-alone socket to avoid the deployment of filter placement area inside the lens barrel, wherein the thickness is effectively reduced and the lens module becomes thinner. 
     Another object of the present invention is to provide a lens module in which a holder is utilized to fix the filter on the stand-alone socket. The holder allows the lens module to be reassembled, facilitates the assembling process, and raises the yield of assembly. 
     Still another object of the present invention is to provide a lens module in which a holder is used to fix the filter on the stand-alone socket. When the lens module is de-assembled, damages to the filter and the socket can be prevented by using such method and the production cost can thus be effectively reduced. 
     According to the above objects, the present invention provides an image sensing module, which includes a socket, a circuit board, an image sensor, an elastic element, a filter, and a holder. The socket comprises a circumference wall that is formed around an axis and defines an accommodating space and a supporting platform that extends from the circumference wall to the accommodating space. The socket is disposed with a plurality of fastening protrusions and the holder has a plurality of holes for being engaged by the plurality of fastening protrusions, and thus the aforementioned elastic element and the filter are fixed on the supporting platform of the socket. 
     Moreover, the present invention provides a lens module which includes a lens group, a lens barrel, and an image sensing module. The lens group is disposed inside the lens barrel and an image sensing module is disposed on one side of the lens barrel. The image sensing module includes a socket, a circuit board, an image sensor, an elastic element, a filter, and a holder. The socket comprises a circumference wall that is formed around an axis and defines an accommodating space and a supporting platform that extends from the circumference wall to the accommodating space. The socket is disposed with a plurality of fastening protrusions and the holder has a plurality of holes for being engaged by the plurality of fastening protrusions. Thus the aforementioned elastic element and the filter are fixed on the supporting platform of the socket. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same becomes better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein: 
         FIG. 1  is a cross-sectional view of a lens module of the prior art; 
         FIG. 2  is a cross-sectional view of another lens module of the prior art; 
         FIG. 3  is a cross-sectional view of a lens module of the present invention; 
         FIG. 4  is an exploded view of the first embodiment of the image sensing module of the lens module of the present invention; 
         FIG. 5  is a view of the socket of the image sensing module of the first embodiment; 
         FIG. 6  is a view of the holder of the image sensing module of the first embodiment; 
         FIG. 7  is a view of the completed assembly of the image sensing module of the first embodiment; 
         FIG. 8  is an exploded view of the second embodiment of the image sensing module of the lens module of the present invention; 
         FIG. 9  is a view of the socket of the image sensing module of the second embodiment; 
         FIG. 10  is a view of the holder of the image sensing module of the second embodiment; and 
         FIG. 11  is a view of the completed assembly of the image sensing module of the second embodiment. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     For a comprehensive and clear disclosure of technical contents, the purpose of invention, and the achieved effects, the detailed description taken in conjunction with the drawings and drawing No. is shown below. 
     First, referring to  FIG. 3 , a lens module of the present invention includes a lens group  1 , a lens barrel  2 , and an image sensing module  3 ,  3 ′. The lens barrel  2  comprises a first circumference wall  4  formed around an axis L 1 , a second circumference wall  5  formed around the same axis L 1  as the first circumference wall  4 , and a shoulder  6  connecting the first circumference wall  4  to the second circumference wall  5 . The above-mentioned first circumference wall  4  encloses the first accommodating space  7  for containing the lens group  1 , and the second circumference wall  5  encloses the second accommodating space  8  larger than the first vacant space  7  for containing the image sensing module  3 ,  3 ′. The image sensing module  3 ,  3 ′ is fixed to the shoulder  6  between the first circumference wall  4  and second circumference wall  5  by lock-fasteners such as screws. Besides, the image sensing module  3 ,  3 ′ are different embodiments of the present invention and the difference lies in the structure of the holder  70 ,  70 ′. This will be described in detail in the following. 
       FIG. 4  is an exploded view of the first embodiment of the image sensing module  3  of the lens module as shown in  FIG. 3 .  FIG. 5  is a view of the socket  10  of the image sensing module  3  of the first embodiment.  FIG. 6  is a view of the holder  70  of the image sensing module  3  of the first embodiment.  FIG. 7  is a view of the completed assembly of the image sensing module  3  of the first embodiment. The structure of the image sensing module  3  of the present invention will be described in detail in the following. 
     The image sensing module  3  of the first embodiment comprises a socket  10 , an image sensor  20  disposed in the rectangular opening  12  of the socket  10 , a circuit board  30  electrically connected to the image sensor  20 , a shading sheet  40 , an elastic element  50 , a filter  60 , and a holder  70 . 
     The socket  10  comprises a base plate  11  on which a hollowed-out rectangular opening  12  is formed by the octagonal barrel portion  13  with four corners being cut out, wherein the barrel portion  13  comprises an inner sidewall  14  surrounding the same axis L 1  as the lens barrel  2  of the lens module and an outer sidewall  15  on the other side of the inner sidewall  14 . Therefore, the barrel portion  13  of the image sensing module  3  of the first embodiment includes four sides  151  and three bevels  152  connecting to the sides  151 . The above-mentioned inner sidewall  14  and the rectangular opening  12  form an accommodating space; therefore, when the circuit board  30  is dispensed to be fixed below the socket  10 , the image sensor  20  on the circuit board  30  can be placed in the accommodating space formed by the inner sidewall  14  and the rectangular opening  12 . Moreover, a plurality of rectangular supporting platforms  16  (one pair at least with each supporting platform  16  on the opposite side for example) can be further disposed on the inner sidewall  14  of the barrel portion  13 , wherein the height of supporting platform  16  is smaller than that of the barrel portion  13  so that a platform can be formed with the difference of height between the barrel portion  13  and the supporting platform  16  and that the shading sheet  40 , elastic element  50 , and filter  60  can be placed on the supporting platform  16 . Furthermore, another accommodating space can also be formed between the inner part of the supporting platform  16  and the rectangular opening  12 . When the inner sidewall  14  of the barrel portion  13  is disposed with the supporting platform  16 , the image sensor  20  can be placed inside the accommodating space inside the supporting platform  16  depending on the requirements of the design. Furthermore, at least one of the four sides  151  of the outer sidewall  15  of the barrel portion  13  is disposed with fastening protrusions  1511 , or two opposite sides  151  are disposed with fastening protrusions  1511 , and other opposite sides  151  may disposed with one fastening protrusion  1511 . In another embodiment, at least one side  151  and/or at least one bevel  152  of the barrel portion  13  is disposed with at least one fastening protrusion  1511 . 
       FIG. 6  is a view of the holder of the image sensing module of the first embodiment of the present invention. As shown in  FIG. 6 , the holder  70  is a hollowed-out octagonal structure with an opening  74 , four sides  71  of which are parallel to the four sides  151  of the outer sidewall  15  of the socket  10 , but one side  71 B of which is shorter than the other three sides  71 A due to the opening  74 . Holes  711  are disposed respectively near the center of each of the four sides  71  of the holder  70  to be engaged by the fastening protrusions  1511  on the outer sidewall  15  of the socket  10  for the holder  70  and the socket  10  to be firmly assembled together. Moreover, flanges  72  perpendicular to the sides  71  extend respectively between the four sides  71  (i.e. three corners of the holder  70 ), and only one side of the shorter side  71 B is disposed with the flange  72  and the other side is a free end or open end. Therefore, the end of one side  71 C among the three sides  71 A is not connected to the shorter side  71 B, and a short flange  72 B extends from the open end of the side  71 C. Each of the above four sides  71  has a hole  711  which is used for being engaged by the fastening protrusion  1511  of the socket  10  for the holder  70  and the socket  10  to be firmly assembled. When the holder  70  is assembled with the socket  10 , the above four flanges  72 ,  72 B can be used to press the shading sheet  40 , the elastic element  50 , and the filter  60  for the shading sheet  40 , the elastic element  50 , and the filter  60  to be placed between the flanges  72 ,  72 B and the supporting platform  16  of the socket  10 . In an embodiment, the shorter flange  72 B and the shorter side  71 B are disconnected to form the opening  74 . 
     In the embodiment above, the image sensor  20  can be Complementary Metal-Oxide-Semiconductor (CMOS) or Charge-Coupled Device (CCD) image sensor and the circuit board  30  can be a Flexible Printed Circuit (FPC). The elastic element  50  can be made of a kind of high polymer material to make sure the image sensor  20  is not influenced by dust or mist. Moreover, the filter  60  can be used to absorb red light, infrared light, or lights of which the wavelengths are close to that of the infrared light. Additionally, the holder  70  of the present invention can be made of metal and formed by stamping or made of engineering plastics and formed by injection molding, which is not limited in the present invention. 
     As shown in  FIG. 4 , the shading sheet  40 , the elastic element  50 , and the filter  60  are placed sequentially on the supporting platform  16 , and the holder  70  is used to fasten these components to the socket  10  and fixed between the supporting platform  16  and the flanges  72 ,  72 B of the holder  70 . The image sensor  20  is first fixed on the circuit board  30  by employing surface adhering technique, and then the circuit board  30  is dispensed to be fixed behind the socket  10 . Thus, the image sensor  20  can be placed inside the supporting platform  16  and be assembled into the image sensing module  3  as shown in  FIG. 7 . The image sensing module  3  is further fixed to the shoulder  6  as shown in  FIG. 3  with lock-fasteners such as the screws (omitted in the figure) for the image sensing module  3  to be placed in the second accommodating space  8 . 
     Apparently, due to the suitable design of the holder  70 , the total thickness is approximately equivalent to the depth of the side  71 ; and the width of the side  71  of the holder  70  can be designed as slightly smaller than the width of the outer sidewall  15  of the socket  10  so that the fastening protrusions  1511  passing through the holes  711  respectively can be protruded out of the sides  71  of the holder  70 . Additionally, as the image sensor  20  is placed in the accommodating space inside the supporting platform  16  of the socket  10 , the total thickness of the image sensing module is roughly the sum of the thickness of the socket  10  and that of the circuit board  30 , and the thickness of the image sensing module  3  can be effectively reduced, which allows the lens to be thinner. Furthermore, the holder  70  is buckled with the socket  10  through lock-fasteners, and thus the lens module can be repeatedly re-assembled and more easily assembled, and the yield of assembly can also be raised. 
     Furthermore, a recess  131  can be further formed on one side of the octagonal barrel portion  13  in the first embodiment. As  FIG. 5  shows, a recess  131  is formed on one side of the octagonal barrel portion  13 , and the side on which the recess  131  is located is parallel to the shorter side  71 B of the holder  70 . Thus when the holder  70  is fixed on the octagonal barrel portion  13 , the recess  131  corresponding to the opening  74  will be exposed. The purpose for designing the recess  131  is to provide a channel through which the control lines of the image sensor  20  can pass, as shown in  FIG. 7 . 
     Referring then to  FIG. 8 , which is an exploded view of the second embodiment of image sensing module  3 ′ of the lens module as shown in  FIG. 3 .  FIG. 9  is a view of the socket of the image sensing module  3 ′ of the second embodiment.  FIG. 10  is a view of the holder of the image sensing module  3 ′ of the second embodiment.  FIG. 11  is a view of the completed assembly of the image sensing module  3 ′ of the second embodiment. 
     The image sensing module  3 ′ of the second embodiment, similar to the image sensing module  3  of the first embodiment, includes a socket  10 ′, an image sensor  20  disposed in the rectangular opening  12 ′ of the socket  10 , a circuit board  30  electrically connected to the image sensor  20 , a shading sheet  40 , an elastic element  50 , a filter  60 , and a holder  70 ′. 
     Referring to  FIG. 9 , the socket  10 ′ of the image sensing module  3 ′ of the second embodiment, being similar to the socket  10  of the first embodiment, comprises a base plate  11 ′, on which is disposed with a rectangular hollowed-out opening  12 ′ formed by the surrounding of the octagonal barrel portion  13 ′ with four corners being cut out, wherein the barrel portion  13 ′ consists of an inner sidewall  14 ′ surrounding the same axis as the lens barrel  2  of the lens module and an outer sidewall  15 ′ on the other side of the inner sidewall  14 ′. The difference between the second embodiment and the first embodiment lies in that a fastening protrusion  1521 ′ is disposed on at least one of the four bevels  152 ′. In another embodiment, the fastening protrusions  1521 ′ can be disposed on at least two of the bevels  152 ′, at least two of the sides  151 ′ or at least one of the bevels  152 ′ and at least one of the sides  151 ′. At the position on the base  11 ′ of the socket  10  opposite to the aforementioned fastening protrusions  1521 ′, i.e. the projected position of the fastening protrusions  1521 ′ on the base  11 ′, a through hole  111 ′ is disposed to allow the flange  73 ′ of the holder  70 ′ to buckle into. Moreover, a plurality of rectangular supporting platforms  16 ′ (one pair at least with each supporting platform on the opposite side for example) can be further placed on the inner sidewall  14 ′ of the barrel portion  13 ′ in the present embodiment, wherein the height of the supporting platform  16 ′ is smaller than that of the barrel portion  13 ′ so that a platform can be formed due to the difference of height between the barrel portion  13 ′ and the supporting platform  16  and the shading sheet  40 , elastic element  50 , and filter  60  can thus be placed on the supporting platform  16 ′. Meantime, an accommodation space can also be formed by the inner part of the supporting platform  16 ′ and the rectangular opening  12 ′. Depending on the requirement of the design, when the inner sidewall  14 ′ of the barrel portion  13 ′ is disposed with a supporting platform  16 ′, the image sensor  20  will be placed inside the accommodating space inside the supporting platform  16 ′. As shown in  FIG. 9 , a recess  131 ′ is formed on one side of the octagonal barrel portion  13 ′. When the holder  70 ′ is fixed on the octagonal barrel portion  13 ′, the recess  131 ′ corresponding to the opening  74 ′ will be exposed. 
     Referring to  FIG. 10 , the holder  70 ′ is an hollowed-out octagonal-shaped structure with an opening  74 ′ to correspond with the design of the outer sidewall  15 ′ of the barrel portion  13 ′ and comprises four sides  71 ′ but one side  71 B′ is shorter than the other three side  71 ′. The four sides  71 ′ are parallel to the side  151 ′ of the outer sidewall  15 ′ of the socket  10 ′ and connect among one another through the first flange  72 ′ perpendicular to and extending from the sides  71 ′. The first flange  72 ′ is one bevel of the octagonal structure and is used to press the shading sheet  40 , the elastic element  50 , and the filter  60  for the shading sheet  40 , the elastic element  50 , and the filter  60  to be placed between the first flange  72 ′ and the supporting platform  16 ′ of the socket  10 ′. A second flange  73 ′ parallel to the bevel  152 ′ of the outer sidewall  15 ′ extends from the middle of the first flange  72 ′, and each of the second flanges  73 ′ is vertical to the bevel and has a hole  731 ′. The second flanges  73 ′ can enter the first through hole  111 ′ of the socket  10 ′, and the fastening protrusions  1521 ′ of the socket  10 ′ can engage with the hole  731 ′ on the second flange  73 ′ and are protruded out the bevels of the holder  70 ′, allowing the holder  70 ′ and the socket  10 ′ to be firmly assembled. In an embodiment, the shorter flange  72 B′ and the shorter side  71 B′ are disconnected to form the opening  74 ′. 
     The image sensor  20 , the elastic element  50 , the filter  60 , and the holder  70 ′ of the second embodiment are made of the same material in the same method as those of the first embodiment and thus the manufacturing method is not described in detail. Similarly, the shading sheet  40 , the elastic element  50 , and the filter  60  are sequentially placed on the supporting platform  16 ′ and buckled into the socket  10 ′ via the holder  70 ′ for being fixed between the supporting platform  16 ′ and the first flange  72 ′ of the holder  70 ′. The image sensing module  3 ′ is assembled as shown in  FIG. 11 , wherein the image sensor  20  is first fixed on the circuit board  30  by employing surface adhering technique, and then the circuit board  30  is dispensed to be fixed behind the socket  10 ′. The image sensing module  3 ′ is further fixed on the shoulder  6  as shown in  FIG. 3  with lock-fasteners such as the screws (omitted in the figure) to be placed in the second accommodating space  8 . As the present embodiment differs from the first embodiment only in changes of the design of the barrel portion  13 ′ and of the holder  70 ′, the effects achieved by the present embodiment is the same as those achieved by the first embodiment. 
     In addition to the two embodiments described above, the image sensing module of the present invention can also one which includes the aforementioned image sensing module but excludes the shading sheet  40 , namely, an image sensing module that includes only a socket  10 ,  10 ′, an image sensor  20 , a circuit board  30 , an elastic element  50 , a filter  60 , and one holder  70 ,  70 ′, or an image sensing module that includes only a socket  10 ,  10 ′, an image sensor  20 , a circuit board  30 , a filter  60 , and one holder  70 ,  70 ′. Moreover, in the image sensing module  3 ,  3 ′ of the present invention, the fastening protrusions  1511 ,  1521 ′ can also be disposed on the holder  70 ,  70 ′ and the holes  711 ,  731 ′ can be disposed on the socket  10 ,  10 ′, and the holder  70 ,  70 ′ and the socket  10 ,  10 ′ can still be firmly assembled. That is, the fastening protrusions  1511 ,  1521 ′ can be disposed on at least one of sides  71 ,  71 ′, at least one of flanges  72 ,  72 ′ or at least one of the sides  71 ,  71 ′ and at least one of the flange  72 ,  72 ′. 
     While the invention has been described by way of examples and in terms of the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements as would be apparent to those skilled in the art. Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.