Patent Publication Number: US-11642016-B2

Title: Image capturing module, endoscope and method of manufacturing image capturing module

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to an image capturing module and, more particularly, to an image capturing module adapted to an endoscope and a method of manufacturing the image capturing module. 
     2. Description of the Prior Art 
     Endoscope is a medical instrument that enters a human body through various channels to observe internal conditions of the human body. In general, the endoscope comprises an elongated tube for being inserted into the human body and an image sensor disposed in the elongated tube for capturing inside images of the human body. The thicker the tube is, the more uncomfortable the human body feels. To reduce the thickness of the tube, a micro image sensor has been developed. The micro image sensor is disposed in the elongated tube by a flexible circuit board. However, it is difficult to dispose such a micro image sensor with small dimensions (e.g. 650 μm*650 μm*1158 μm) on a corresponding flexible circuit board. 
     SUMMARY OF THE INVENTION 
     The invention provides an image capturing module adapted to an endoscope and a method of manufacturing the image capturing module, so as to solve the aforesaid problems. 
     According to an embodiment of the invention, an image capturing module comprises a flexible circuit board and an image sensor. The flexible circuit board comprises a plurality of first pads and a plurality of second pads. The first pads are disposed on a first surface of the flexible circuit board and the second pads are disposed on a second surface of the flexible circuit board, wherein the first surface is opposite to the second surface. The image sensor is disposed on the first surface. A distance between the image sensor and the first pads is identical to a distance between the image sensor and the second pads. The flexible circuit board is folded to align and weld the first pads with the second pads, such that a light receiving surface of the image sensor is perpendicular to surfaces of the first and second pads. 
     According to another embodiment of the invention, an endoscope comprises a tube and an image capturing module. The image capturing module is disposed in the tube. The image capturing module comprises a flexible circuit board and an image sensor. The flexible circuit board comprises a plurality of first pads and a plurality of second pads. The first pads are disposed on a first surface of the flexible circuit board and the second pads are disposed on a second surface of the flexible circuit board, wherein the first surface is opposite to the second surface. The image sensor is disposed on the first surface. A distance between the image sensor and the first pads is identical to a distance between the image sensor and the second pads. The flexible circuit board is folded to align and weld the first pads with the second pads, such that a light receiving surface of the image sensor is perpendicular to surfaces of the first and second pads. 
     According to another embodiment of the invention, a method of manufacturing an image capturing module comprises steps of forming a plurality of first pads and a plurality of second pads on a flexible circuit board, wherein the first pads is disposed on a first surface of the flexible circuit board, the second pads is disposed on a second surface of the flexible circuit board, and the first surface is opposite to the second surface; disposing an image sensor on the first surface, wherein a distance between the image sensor and the first pads is identical to a distance between the image sensor and the second pads; folding the flexible circuit board to align the first pads with the second pads and make a light receiving surface of the image sensor perpendicular to surfaces of the first and second pads; and welding the first pads with the second pads. 
     As mentioned in the above, the invention disposes the image sensor on the flexible circuit board first and then folds the flexible circuit board to weld the first pads with the second pads thereon. At this time, the light receiving surface of the image sensor is perpendicular to surfaces of the first and second pads. Accordingly, the folded flexible circuit board with the image sensor can be directly inserted into an elongated tube to form an endoscope, such that the method of manufacturing the endoscope can be simplified and the flexible circuit board of the invention can be used for installing a micro image sensor with small dimensions. 
     These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a perspective view illustrating an image capturing module before being folded according to an embodiment of the invention. 
         FIG.  2    is a perspective view illustrating parts of the image capturing module shown in  FIG.  1    from another viewing angle. 
         FIG.  3    is a schematic view illustrating the image capturing module shown in  FIG.  1   . 
         FIG.  4    is a perspective view illustrating parts of the image capturing module shown in  FIG.  1    after being folded. 
         FIG.  5    is a perspective view illustrating an endoscope  1  equipped with the image capturing module shown in  FIG.  4   . 
         FIG.  6    is a perspective view illustrating the inside of the endoscope shown in  FIG.  5   . 
         FIG.  7    is a perspective view illustrating parts of the image capturing module according to another embodiment of the invention. 
         FIG.  8    is a perspective view illustrating the image capturing module shown in  FIG.  7    after being folded. 
         FIG.  9    is a perspective view illustrating parts of the image capturing module according to another embodiment of the invention. 
         FIG.  10    is a perspective view illustrating the image capturing module shown in  FIG.  9    after being folded. 
         FIG.  11    is a flowchart illustrating a method of manufacturing the image capturing module according to an embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIGS.  1  to  4   ,  FIG.  1    is a perspective view illustrating an image capturing module  10  before being folded according to an embodiment of the invention,  FIG.  2    is a perspective view illustrating parts of the image capturing module  10  shown in  FIG.  1    from another viewing angle,  FIG.  3    is a schematic view illustrating the image capturing module  10  shown in  FIG.  1   , and  FIG.  4    is a perspective view illustrating parts of the image capturing module  10  shown in  FIG.  1    after being folded. 
     As shown in  FIGS.  1  to  3   , an image capturing module  10  before being folded comprises a flexible circuit board  100 , an image sensor  102 , at least one light emitting unit  104  and at least one electrical component  106 . In this embodiment, the flexible circuit board  100  may be a flexible printed circuit board or other flexible circuit boards, the image sensor  102  may be a charge coupled device (CCD) image sensor, a complementary metal oxide semiconductor (CMOS) image sensor or other image sensors, the light emitting unit  104  may be a light emitting diode or other light emitting components, and the electrical component  106  may be a capacitor or other electrical components. 
     The flexible circuit board  100  comprises a plurality of first pads  1000 , a plurality of second pads  1002  and a plurality of third pads  1004 . In this embodiment, the flexible circuit board  100  may comprise four first pads  1000 , four second pads  1002  and four third pads  1004 , but the invention is not so limited. The number of the first pads  1000 , the second pads  1002  and the third pads  1004  may be determined according to practical applications. 
     The first pads  1000  may be disposed on a first surface S 1  of the flexible circuit board  100  and the second pads  1002  may be disposed on a second surface S 2  of the flexible circuit board  100 , wherein the first surface S 1  is opposite to the second surface S 2 . For further illustration, one of the first surface S 1  and the second surface S 2  may be au upper surface of the flexible circuit board  100 , and the other one of the first surface S 1  and the second surface S 2  may be a lower surface of the circuit board  100 . 
     In this embodiment, the first pads  1000  may be located at a first portion P 1  of the flexible circuit board  100 , the second pads  1002  may be located at a second portion P 2  of the flexible circuit board  100 , and the third pads  1004  may be located at a third portion P 3  of the flexible circuit board  100 , wherein the second portion P 2  is connected to the first portion P 1  and the third portion P 3  is connected to the second portion P 2 . In other words, the second portion P 2  is connected between the first portion P 1  and the third portion P 3 . 
     In this embodiment, the first pads  1000  are wider than the second pads  1002 . As shown in  FIG.  3   , the second portion P 2  may be wider than the first portion P 1  and a width W of the second pads P 2  may be equal to a width difference Wd between the first portion P 1  and the second portion P 2 . Furthermore, the third portion P 3  may be wider than the second portion P 2 . The third pads  1004  are used for connecting a cable (not shown). Therefore, the wider the third portion P 3  is, the easier the cable can be welded with the third pads  1004 . 
     The image sensor  102  is disposed on the first surface S 1  of the flexible circuit board  100 , wherein a distance D 1  between the image sensor  102  and the first pads  1000  is identical to a distance D 2  between the image sensor  102  and the second pads  1002 , as shown in  FIG.  3   . In other words, before the flexible circuit board  100  is folded, the image sensor  102  is located at a middle position between the first pads  1000  and the second pads  1002 . In this embodiment, the image sensor  102  may be connected to the first surface S 1  of the flexible circuit board  100  by surface mount technology (SMT), but the invention is not so limited. 
     In this embodiment, the image capturing module  10  may comprise two light emitting units  104 , but the invention is not so limited. The light emitting units  104  are disposed on the first surface S 1  of the flexible circuit board  100 , wherein a distance D 3  between the image sensor  102  and each of the light emitting units  104  is smaller than the distance D 1  or D 2  between the image sensor  102  and the first or second pads  1000 ,  1002 , as shown in  FIG.  3   . That is to say, the light emitting units  104  are closer to the image sensor  102  than the first or second pads  1000 ,  1002 . 
     In this embodiment, the image capturing module  10  may comprise one electrical component  106 , but the invention is not so limited. The electrical component  106  may be disposed on the second surface S 2  of the flexible circuit board  100  with respect to the image sensor  102 . In other words, the image sensor  102  and the electrical component  106  are disposed on opposite surfaces of the flexible circuit board  100 . 
     In this embodiment, the flexible circuit board  100  may comprises a first folding segment  1006 , a second folding segment  1008  and a third folding segment  1010 , wherein the first folding segment  1006  is connected between the second folding segment  1008  and the third folding segment  1010 . The image sensor  102  and the electrical component  106  is located at opposite surfaces of the first folding segment  1006 , and the two light emitting units  104  are respectively located at the second folding segment  1008  and the third folding segment  1010 . It should be noted that, in another embodiment, the image capturing module  10  may comprise one light emitting unit  104  located at one of the second folding segment  1008  and the third folding segment  1010 . Accordingly, the image capturing module  10  may comprise at least one light emitting unit  104  located at at least one of the second folding segment  1008  and the third folding segment  1010 . 
     In this embodiment, the image sensor  102 , the light emitting units  104  and the electrical component  106  may be connected to the flexible circuit board  100  by surface mount technology (SMT) in one process. Then, as shown in  FIG.  4   , the flexible circuit board  100  is folded to align and weld the first pads  1000  with the second pads  1002 , such that a light receiving surface  1020  of the image sensor  102  is perpendicular to surfaces of the first and second pads  1000 ,  1002 . After the flexible circuit board  100  is folded, the first portion P 1  is superimposed on the second portion P 2 , the first folding segment  1006  is perpendicular to the second folding segment  1008  and the third folding segment  1010 , and the second folding segment  1008  and the third folding segment  1010  are parallel to each other. Furthermore, joints  1012  between the first folding segment  1006 , the second folding segment  1008  and the third folding segment  1010  have rounded recess structures  1014 . Accordingly, the first folding segment  1006 , the second folding segment  1008  and the third folding segment  1010  may be folded at the joints  1012  according to the rounded recess structures  1014 . 
     Referring to  FIGS.  5  and  6   ,  FIG.  5    is a perspective view illustrating an endoscope  1  equipped with the image capturing module  10  shown in  FIG.  4    and  FIG.  6    is a perspective view illustrating the inside of the endoscope  1  shown in  FIG.  5   . 
     As shown in  FIG.  5   , an endoscope  1  comprises the aforesaid image capturing module  10  and a tube  12 , wherein the image capturing module  10  is disposed in the tube  12 . For further illustration, after the flexible circuit board  100  is folded and the first pads  1000  are welded with the second pads  1002 , the folded flexible circuit board  100  with the image sensor  102  can be directly inserted into the elongated tube  12  to form the endoscope  1 . As shown in  FIG.  6   , the endoscope  1  may further comprise a light guide structure  14  disposed in the tube  12 . In this embodiment, the endoscope  1  may comprise two light guide structures  14  corresponding to the two light emitting units  104 , but the invention is not so limited. After the image capturing module  10  is inserted into the tube  12 , each of the light emitting units  104  is adjacent to the corresponding light guide structure  14 , such that the light guide structure  14  is able to guide light emitted by the light emitting unit  104  out of the tube  12 . 
     Referring to  FIGS.  7  and  8   ,  FIG.  7    is a perspective view illustrating parts of the image capturing module  10  according to another embodiment of the invention and  FIG.  8    is a perspective view illustrating the image capturing module  10  shown in  FIG.  7    after being folded. 
     As shown in  FIG.  7   , the image capturing module  10  may further comprise two support members  108 , wherein the two support members  108  are disposed on the second surface S 2  of the flexible circuit board  100  and respectively located at the second folding segment  1008  and the third folding segment  1010 . As shown in  FIG.  8   , after the flexible circuit board  100  is folded, the two support members  108  abut against each other, such that the light emitting unit  104  can be kept at a fixed position to avoid deviation. Furthermore, in this embodiment, the image capturing module  10  may comprise two electrical components  106 , wherein the two electrical components  106  are disposed on the second surface S 2  of the flexible circuit board  100  with respect to the two light emitting units  104 . In other words, the two light emitting units  104  and the two electrical components  106  are disposed on opposite surfaces of the flexible circuit board  100 . In another embodiment, the electrical component  106  may also be disposed on the first surface S 1  of the flexible circuit board  100  with respect to the light emitting unit  104  and away from the image sensor  102 , so as to avoid that the electrical component  106  occludes the light emitted by the light emitting unit  104  projecting out the tube  12 . Therefore, the electrical component  106  may be disposed on at least one of the first surface S 1  and the second surface S 2  with respect to the light emitting unit  104 . 
     Referring to  FIGS.  9  and  10   ,  FIG.  9    is a perspective view illustrating parts of the image capturing module  10  according to another embodiment of the invention and  FIG.  10    is a perspective view illustrating the image capturing module  10  shown in  FIG.  9    after being folded. 
     As shown in  FIG.  9   , the flexible circuit board  100  of the image capturing module  10  may further comprise at least two fourth pads  1016  and at least two fifth pads  1018  for connecting the image sensor  102 . In this embodiment, the flexible circuit board  100  may comprise two fourth pads  1016  and two fifth pads  1018 , but the invention is not so limited. The two fifth pads  1018  are longer than the two fourth pads  1016 . Furthermore, the two fourth pads  1016  are located at the first folding segment  1006  and the two fifth pads  1018  extend from the first folding segment  1006  to the second folding segment  1008 . 
     In this embodiment, before the flexible circuit board  100  is folded, two contacts  1022  of the image sensor  102  may be connected to the two fourth pads  1016  first by surface mount technology (SMT). Then, the flexible circuit board  100  is folded to align the first pads  1000  with the second pads  1002  and make alight receiving surface  1020  of the image sensor  102  perpendicular to surfaces of the first and second pads  1000 ,  1002 . Then, the other two contacts  1024  of the image sensor  102  are welded to the two fifth pads  1018  on the first surface S 1  of the flexible circuit board  100  while the first pads  1000  are welded with the second pads  1002 . Since the two contacts  1024  of the image sensor  102  are welded to the flexible circuit board  100  after the flexible circuit board  100  is folded, the second folding segment  1008  may be folded closer to the third folding segment  1010 , so as to further reduce the thickness of the folded flexible circuit board  100 . 
     Referring to  FIG.  11   ,  FIG.  11    is a flowchart illustrating a method of manufacturing the image capturing module  10  according to an embodiment of the invention. 
     As shown in  FIGS.  1  to  11   , first, step S 10  is performed to form a plurality of first pads  1000  and a plurality of second pads  1002  on a flexible circuit board  100 , wherein the first pads  1000  is disposed on a first surface S 1  of the flexible circuit board  100 , the second pads  1002  is disposed on a second surface S 2  of the flexible circuit board  100 , and the first surface S 1  is opposite to the second surface S 2 . Then, step S 12  is performed to dispose an image sensor  102  on the first surface S 1 , wherein a distance D 1  between the image sensor  102  and the first pads  1000  is identical to a distance D 2  between the image sensor  102  and the second pads  1002 . Then, step S 14  is performed to fold the flexible circuit board  100  to align the first pads  1000  with the second pads  1002  and make a light receiving surface  1020  of the image sensor  102  perpendicular to surfaces of the first and second pads  1000 ,  1002 . Then, step S 16  is performed to weld the first pads  1000  with the second pads  1002 . 
     In this embodiment, the step S 12  may further comprise step of disposing at least one light emitting unit  104  on the first surface S 1 , wherein a distance D 3  between the image sensor  102  and the at least one light emitting unit  104  is smaller than a distance d 1  or D 2  between the image sensor  102  and the first or second pads  1000 ,  1002 . 
     According to the embodiments shown in  FIGS.  1  to  4 ,  7  and  8   , the step S 12  may further comprise step of connecting the image sensor  102  to the first surface S 1  of the flexible circuit board  100  by surface mount technology (SMT). 
     According to the embodiment shown in  FIGS.  9  and  10   , the step S 12  may further comprise step of connecting at least two contacts  1022  of the image sensor  102  to the first surface S 1  of the flexible circuit board  100  by surface mount technology (SMT), and the step S 16  may further comprise step of welding at least two contacts  1024  of the image sensor  102  to the first surface S 1  of the flexible circuit board  100 . 
     It should be noted that the detailed embodiments of the method of manufacturing the image capturing module  10  of the invention are mentioned in the above and those will not be depicted herein again. 
     As mentioned in the above, the invention disposes the image sensor on the flexible circuit board first and then folds the flexible circuit board to weld the first pads with the second pads thereon. At this time, the light receiving surface of the image sensor is perpendicular to surfaces of the first and second pads. Accordingly, the folded flexible circuit board with the image sensor can be directly inserted into an elongated tube to form an endoscope, such that the method of manufacturing the endoscope can be simplified and the flexible circuit board of the invention can be used for installing a micro image sensor with small dimensions. 
     Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.