Patent Publication Number: US-10313567-B2

Title: Camera module and electronic device

Description:
CROSS-REFERENCE PARAGRAPH 
     The present application is a continuation application of U.S. patent application Ser. No. 14/408,110, filed Dec. 15, 2014, which is a National Stage of PCT/JP2013/066912, filed Jun. 20, 2013, and claims the benefit of priority from prior Japanese Patent Applications JP 2013-111767, filed May 28, 2013, JP 2013-055149, filed Mar. 18, 2013, and JP 2012-147878, filed Jun. 29, 2012, each of the above-referenced applications is hereby incorporated herein by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     The present technology relates to a camera module and an electronic device, and in particular, to a camera module in which a thin camera module can be realized at a low cost and an electronic device. 
     BACKGROUND ART 
     In a conventional camera module structure, FPC (Flexible Printed Circuits) are disposed on the lower side of a module and are connected by soldering or by ACF (Anisotropic Conductive Film) (for example, see Patent Document 1). 
     As such, the thickness of the FPC and the thickness of the connecting portion (solder connection or ACF connection) are included in the height of the module such as a lens unit, whereby there is a problem that the thickness of the module increases. 
     Meanwhile, a rigid flexible substrate, in which a rigid portion and a flexible portion are integrated, may also be used. In that case, there is no need to take into account a connection between the rigid substrate and the FPC. 
     CITATION LIST 
     Patent Document 
     Patent Document 1: Japanese Patent Application Laid-Open No. 2009-033481 
     SUMMARY OF THE INVENTION 
     Problems to be Solved by the Invention 
     However, in the case of using a rigid flexible substrate, constraints on the design increases, compared with the case of a configuration in which a rigid substrate and FPC are connected, for example. 
     For example, in the case of using a rigid flexible substrate, as it is necessary to conform the pitch of vias and the width of wiring to design rules of the flexible portion in the substrate, it is difficult to perform fine wiring in the rigid portion in the substrate. 
     Further, in the case of using a rigid flexible substrate, as a layer constituting the flexible portion is inserted between layers constituting the rigid portion, a range of process conditions such as an ultrasonic wave, temperature setting, and the like becomes narrow when an image sensor is wire-bonded, and the like. 
     Further, in the case of using a rigid flexible substrate, as a member usage rate decreases in each of the layer constituting the rigid portion and the layer constituting the flexible portion, the substrate cost increases. As such, it is difficult to suppress the cost of the entire camera module. 
     Further, in the case of using a rigid flexible substrate, when attempting to change the shape of the flexible portion corresponding to a device (mobile telephone, smartphone, or the like) in which the camera module is incorporated, for example, it is necessary to redesign the entire substrate including the rigid portion. As such, the delivery period of the substrate becomes longer, for example, and the cost further increases. 
     The present technology is disclosed in view of such a situation, and aims to realize a thin camera module at a low cost. 
     Solutions to Problems 
     A first aspect of the present technology is a camera module including: a lens unit that stores a lens that condenses light on a light receiving surface of an image sensor; a rigid substrate on which the image sensor is disposed; and a flexible substrate electrically connected with the rigid substrate, wherein in a case where the light receiving surface of the image sensor locates at the top, the lens unit, the flexible substrate, and the rigid substrate are disposed in this order from the top. 
     In the rigid substrate of a square shape, in an overlap region of a band shape having a predetermined distance from an end of one side of the square, the rigid substrate is disposed to overlap a portion of the flexible substrate, and the rigid substrate and the flexible substrate are attached to each other. 
     The overlap region is a band-shaped region having a width of 2.4 mm or less. 
     In the flexible substrate, besides the overlap region, a reinforced region in which the flexible substrate overlaps the rigid substrate is provided. 
     The reinforced region is provided to extend in parallel with two sides of the image sensor of the square shape. 
     The reinforced region is provided to extend in parallel with one side of the image sensor of the square shape. 
     In the rigid substrate of a square shape, a solder resist is removed in a band-shaped region having a predetermined distance from an end of one side of the square. 
     A groove for accommodating an end portion of the flexible substrate is formed in the lens unit. 
     A frame is further provided between the lens unit and the flexible substrate. 
     A groove for accommodating an end portion of the flexible substrate is formed in the frame. 
     An electrode pad of the image sensor and an embedded electrode provided in the flexible substrate are connected with each other by wire bonding, and a signal output from the electrode pad of the image sensor is transmitted to the rigid substrate through the embedded electrode. 
     The embedded electrode is formed by punching all layers of the flexible substrate having a multilayer structure to thereby form an opening, and embedding metal in the opening. 
     The electrode pad is formed by punching an uppermost layer of the flexible substrate having a multilayer structure to thereby form an opening, and embedding metal in the opening, and an electrode pad of the image sensor and the electrode pad provided in the flexible substrate are connected with each other by wire bonding. 
     An electrode pad of the image sensor and a stud bump protruding on the rigid substrate are connected by wire bonding. 
     An opening is formed by punching all layers of the flexible substrate having a multilayer structure, and 
     the stud bump is formed on an electrode pad which is on the rigid substrate and is located at a position corresponding to the opening. 
     In the flexible substrate having a multilayer structure, an opening formed by punching all layers and an opening formed by punching an uppermost layer of the flexible substrate are provided in a region connected with an electrode pad of the image sensor by wire bonding. 
     In the first aspect of the present technology, in a case where the light receiving surface of the image sensor locates at the top, the camera module is configured such that the lens unit, the flexible substrate, and the rigid substrate are disposed in this order from the top. 
     A second aspect of the present technology is a camera module manufactured by a method including the steps of: disposing a rigid substrate; connecting a flexible substrate with the rigid substrate; and disposing a lens unit on the rigid substrate, the lens unit storing a lens that condenses light on a light receiving surface of the image sensor, wherein in the step of connecting the flexible substrate with the rigid substrate, in the rigid substrate of a square shape, in an overlap region of a band shape having a predetermined distance from an end of one side of the square, the rigid substrate is disposed to overlap a portion of the flexible substrate, and the rigid substrate and the flexible substrate are attached to each other. 
     In the second aspect of the present technology, a rigid substrate is disposed; a flexible substrate is connected with the rigid substrate; and a lens unit is disposed on the rigid substrate, the lens unit storing a lens that condenses light on a light receiving surface of an image sensor, wherein in the step of connecting the flexible substrate with the rigid substrate, in the rigid substrate of a square shape, in an overlap region of a band shape having a predetermined distance from an end of one side of the square, the rigid substrate is disposed to overlap a portion of the flexible substrate, and the rigid substrate and the flexible substrate are attached to each other. 
     A third aspect of the present technology is an electronic device including a camera module including: a lens unit that stores a lens that condenses light on a light receiving surface of an image sensor; a rigid substrate on which the image sensor is disposed; and a flexible substrate electrically connected with the rigid substrate, wherein in a case where the light receiving surface of the image sensor locates at the top, the lens unit, the flexible substrate, and the rigid substrate are disposed in this order from the top. 
     In the third aspect of the present technology, in a case where the light receiving surface of the image sensor locates at the top, the camera module is configured such that the lens unit, the flexible substrate, and the rigid substrate are disposed in this order from the top. 
     Effects of the Invention 
     According to the present technology, a thin camera module can be realized at a low cost. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view illustrating an exemplary configuration of a conventional camera module. 
         FIG. 2  is a side view explaining an exemplary configuration of a conventional camera module. 
         FIG. 3  is a side view illustrating an exemplary configuration of a modification of the camera module illustrated in  FIG. 2 . 
         FIG. 4  is a side view explaining an exemplary configuration of a camera module to which the present technology is applied. 
         FIGS. 5A and 5B  are another side views explaining an exemplary configuration of a camera module to which the present technology is applied. 
         FIG. 6  is a plan view of the camera module illustrated in  FIGS. 5A and 5B , seen from the upper direction of  FIGS. 5A and 5B . 
         FIG. 7  is another plan view of the camera module illustrated in  FIGS. 5A and 5B , seen from the upper direction of  FIGS. 5A and 5B . 
         FIG. 8  is a plan view illustrating a detailed exemplary configuration of a frame of  FIG. 7 . 
         FIG. 9  is a cross-sectional view of the frame taken along an alternate long and short dash line A-A′ of  FIG. 8 . 
         FIG. 10  is a plan view illustrating another detailed exemplary configuration of the frame of  FIG. 7 . 
         FIG. 11  is a cross-sectional view of the frame taken along an alternate long and short dash line A-A′ of  FIG. 10 . 
         FIG. 12  is a plan view of the camera module illustrated in  FIGS. 5A and 5B , seen from the upper direction of  FIGS. 5A and 5B . 
         FIG. 13  is a plan view illustrating a configuration of a flexible substrate and a rigid substrate, illustrated in  FIG. 12 , in detail. 
         FIGS. 14A, 14B, 14C, 14D, 14E and 14F  are diagrams illustrating an exemplary manufacturing process of a camera module to which the present technology is applied. 
         FIG. 15  is a diagram explaining another configuration of a flexible substrate in a camera module to which the present technology is applied. 
         FIG. 16  is a diagram explaining still another configuration of a flexible substrate in a camera module to which the present technology is applied. 
         FIG. 17  is a side view explaining a necessary distance which is a distance from an end of an image sensor to an end of a rigid substrate. 
         FIGS. 18A and 18B  are plan views seen from above of  FIG. 17 . 
         FIG. 19  is a diagram illustrating an example in which an electrode pad of an image sensor and a flexible substrate are directly connected with each other. 
         FIGS. 20A and 20B  are diagrams explaining punching of a flexible substrate. 
         FIGS. 21A and 21B  are side views explaining a method of connecting a rigid substrate and a flexible substrate. 
         FIG. 22  is a plan view seen from above of  FIGS. 21A and 21B . 
         FIGS. 23A and 23B  are side views explaining another example of a method of connecting a rigid substrate and a flexible substrate. 
         FIG. 24  is a side view explaining still another example of a method of connecting a rigid substrate and a flexible substrate. 
         FIG. 25  is a diagram illustrating an enlarged connecting portion between the flexible substrate and the rigid substrate of  FIG. 24 . 
         FIGS. 26A and 26B  are diagrams explaining punching of the uppermost layer of a flexible substrate. 
         FIGS. 27A and 27B  are diagrams explaining a configuration of the entire flexible substrate configured by including the uppermost layer illustrated in  FIGS. 26A and 26B . 
         FIG. 28  is an enlarged view of part of electrode pads and a connection terminal portion in  FIG. 18A . 
         FIG. 29  is a diagram illustrating an example in which an electrode pad of a rigid substrate and a terminal of a connection terminal unit are made common. 
         FIG. 30  is an enlarged view of part of a terminal group of  FIG. 29 . 
         FIG. 31  is a cross-sectional view corresponding to  FIG. 18B . 
         FIG. 32  is a cross-sectional view corresponding to  FIG. 29 . 
         FIG. 33  is a block diagram illustrating an exemplary inner configuration according to an embodiment of a mobile telephone to which the present technology is applied. 
     
    
    
     MODE FOR CARRYING OUT THE INVENTION 
     Hereinafter, embodiments of the technology disclosed herein will be described with reference to the drawings. 
       FIG. 1  is a perspective view illustrating an exemplary configuration of a conventional camera module. A camera module  10  illustrated in the figure is to be installed in an electronic device such as a mobile telephone or a smartphone. 
     The camera module  10  in  FIG. 1  is configured of a lens unit  11 , a frame  12 , a rigid substrate  13 , and a flexible substrate  14 . A flexible substrate is also referred to as FPC (Flexible Printed Circuits). 
     The lens unit  11  is a unit which stores a lens of the camera, and the like. Light condensed through the lens in the lens unit  11  forms an image on a light receiving surface of an image sensor, described below, whereby an image is captured. 
     The frame  12  is a standardized connecting component to be used for connection with the rigid substrate  13 , for example, and is also used for improving shielding property, and the like. It should be noted that the frame  12  may not be provided. In that case, the lens unit  11  is directly attached to the rigid substrate  13 . 
     The rigid substrate  13  is a substrate on which an image sensor of the camera is disposed, for example. 
     The flexible substrate  14  is a substrate on which wiring for inputting and outputting signals, input or output to/from the camera module  10 , to/from another unit of an electronic device is printed, for example. In the example of  FIG. 1 , the flexible substrate  14  is attached to the bottom surface (surface on the lower side in the figure) of the rigid substrate  13 . 
       FIG. 2  is a side view explaining an exemplary configuration of the conventional camera module  10 . It should be noted that in the camera module  10  illustrated in  FIG. 2 , the frame  12  in  FIG. 1  is not provided and the lens unit  11  is directly attached to the rigid substrate  13 . 
     Further, in the example of  FIG. 2 , the flexible substrate  14  is attached to the bottom surface of the rigid substrate  13 , which is the same as the case explained with reference to  FIG. 1 . It should be note that in this example, solder balls  21  used for attaching the flexible substrate  14  and the rigid substrate  13  are illustrated. 
     The thickness (height in the figure) of the camera module  10 , configured as illustrated in  FIG. 2 , is represented as H 1 , and the height H 1  includes the thickness of the flexible substrate  14  and the thickness of the solder ball  21 . Further, the length, in a horizontal direction in the figure, of the camera module  10  is represented as L 1 . It should be noted that in this example, the length in the horizontal direction of the camera module  10  does not include a portion where only the flexible substrate  14  exists. 
     However, as mobile telephones and smartphones are getting thinner increasingly in recent years, it is natural that thinner camera modules are also expected. 
     As such, it is considered to use a rigid flexible substrate in which a rigid portion and a flexible portion are integrated, for example. In that case, it is not necessary to consider connection between the rigid substrate and the flexible substrate. 
     However, in the case of using a rigid flexible substrate, constraints on the design increases, compared with the case of a configuration in which a rigid substrate and a flexible substrate are connected (attached) with each other. 
     For example, in the case of using a rigid flexible substrate, as it is necessary to conform the pitch of vias and the width of wiring to the design rules of the flexible portion in the substrate, it is difficult to perform fine wiring in the rigid portion in the substrate. 
     Further, in the case of using a rigid flexible substrate, as a layer constituting the flexible portion is inserted between layers constituting the rigid portion, a range of process conditions such as an ultrasonic wave, temperature setting, and the like becomes narrow when an image sensor is wire-bonded. 
     Further, in the case of using a rigid flexible substrate, as a member usage rate decreases in each of the layer constituting the rigid portion and the layer constituting the flexible portion, the substrate cost increases. As such, it is difficult to suppress the cost of the entire camera module. 
     Further, in the case of using a rigid flexible substrate, when attempting to change the shape of the flexible portion corresponding to a device (mobile telephone, smartphone, or the like) in which the camera module is incorporated, for example, it is necessary to redesign the entire substrate including the rigid portion. In that case, the delivery period of the substrate becomes longer, for example, and the cost further increases. 
     Meanwhile, as illustrated in  FIG. 3 , the rigid substrate  13  may be configured to protrude from the bottom surface of the lens unit  11  in order to reduce the thickness of the entire module to thereby allow the flexible substrate  14  to be attached on the surface (surface on the upper side in the figure) of the rigid substrate  13 . 
     In the case of configuring the camera module  10  as illustrated in  FIG. 3 , as the thickness of the flexible substrate  14  and the thickness of the solder ball  21  are canceled, the thickness of the camera module  10  is H 2 , which is less than H 1 . As such, it is possible to configure the camera module  10  to be thinner, compared with the case of  FIG. 1 . 
     However, in the case of configuring the camera module  10  as illustrated in  FIG. 3 , as the rigid substrate  13  extends in a horizontal direction in the figure by a length a, the length of the entire camera module in the horizontal direction in the figure also extends. In the example of  FIG. 3 , the length of the camera module  10  in the horizontal direction in the figure is L 2  which is larger than L 1 . 
     As such, in the case of configuring the camera module  10  as illustrated in  FIG. 3 , for example, a mobile telephone, a smartphone, or the like must be designed while taking into account an increase in the length of the camera module  10  in the horizontal direction. 
     In view of the above, the present technology configures a camera module as illustrated in  FIG. 4 , for example. 
       FIG. 4  is a side view explaining an exemplary configuration of a camera module  50  to which the present technology is applied. It should be noted that in the camera module  50  illustrated in  FIG. 4 , the frame described in  FIG. 1  is not provided, and a lens unit  51  is directly attached to the rigid substrate  53 . 
     Further, in the camera module  50  illustrated in  FIG. 4 , a left end portion, in the figure, of a flexible substrate  54  is interposed between the lens unit  51  and the rigid substrate  53 . 
     The camera module  50 , to which the present technology is applied, is configured such that only an end portion on the left side, in the figure, of the flexible substrate  54  is attached to an end portion on the right side, in the figure, of the surface of the rigid substrate  53 . Further, in the camera module  50  to which the present technology is applied, a groove for accommodating the left end portion of the flexible substrate  54  is provided on an end portion on the right side, in the figure, of the lens unit  51 , the details of which will be described below. 
     In the case of configuring the camera module  50  as illustrated in  FIG. 4 , as the thickness of the flexible substrate  54  and the thickness of the solder ball are canceled, the thickness of the camera module  50  is H 2 . As such, it is possible to configure the camera module to be thinner, compared with the case of  FIG. 1 . 
     Further, in the case of configuring the camera module  50  as illustrated in  FIG. 4 , the length of the camera module  50  in the horizontal direction in the figure is L 1 . Accordingly, the length of the entire camera module in the horizontal direction in the figure does not extend, as in the configuration illustrated in  FIG. 3 . 
     Further, in the case of configuring the camera module  50  as illustrated in  FIG. 4 , the length of the flexible substrate  54  in the horizontal direction in the figure can be configured to be shorter. For example, the flexible substrate  54  in  FIG. 4  is configured to have a length shorter by a length L 3  in the horizontal direction in the figure, compared with the case of the flexible substrate  14  in  FIG. 1 , for example. 
     Accordingly, in the case of configuring the camera module  50  as illustrated in  FIG. 4 , the area of the flexible substrate can be reduced by the amount corresponding to the length L 3 , compared with the configuration of  FIG. 1 . This means that by applying the present technology, the area of an expensive flexible substrate is reduced, whereby the cost of the entire camera module can also be reduced. 
       FIGS. 5A and 5B  are another side views explaining an exemplary configuration of the camera module  50  to which the present technology is applied.  FIG. 5A  is a diagram illustrating an exemplary configuration on the case where a frame is not provided in the camera module  50 , and  FIG. 5B  is a diagram illustrating an exemplary configuration of the case where a frame is provided in the camera module  50 . 
     In the camera module  50  illustrated in  FIG. 5A , a left end portion, in the figure, of the flexible substrate  54  is interposed between the lens unit  51  and the rigid substrate  53 . 
     The camera module  50 , to which the present technology is applied, is configured such that only an end portion on the left side, in the figure, of the flexible substrate  54  is attached to an end portion on the right side, in the figure, of the surface of the rigid substrate  53 . Further, in the example of  FIG. 5A , a groove  51   a  for accommodating the left end portion of the flexible substrate  54  is formed in an end portion on the right side, in the figure, of the lens unit  51 . 
     In the camera module  50  illustrated in  FIG. 5B , a frame  52  is provided between the lens unit  51  and the rigid substrate  53 , and a left end portion, in the figure, of the flexible substrate  54  is interposed between the frame  52  and the rigid substrate  53 . Further, in the example of  FIG. 5B , a groove  52   a  for accommodating the left end portion of the flexible substrate  54  is formed in an end portion on the right side, in the figure, of the frame  52 . 
     If the groove  51   a  or the groove  52   a  is not formed, for example, the right side in the figure of the lens unit  51  floats due to the thickness of the flexible substrate  54 , whereby there is a possibility that the light condensed by the lens in the lens unit  51  does not form an image appropriately on the imaging surface of the image sensor on the rigid substrate  53 . Here, in order to allow the light condensed by the lens to form an image appropriately on the imaging surface of the image sensor, it is necessary that the parallel degree of the top surface (surface on the upper side in the figure) of the lens unit  51  and the imaging surface of the image sensor  61  becomes 1.5 degrees or smaller. 
     It should be noted that as the lens unit  51  or the frame  52  is attached to the rigid substrate  53  with an adhesive or the like, by adjusting the thickness of the adhesive, for example, it is possible to perform tilt adjustment so as to set the focus position of the lens in the lens unit  51  to be appropriate. 
     Further, if the groove  51   a  or the groove  52   a  is not formed, the right side, in the figure, of the lens unit  51  floats due to the thickness of the flexible substrate  54 . As such, the adhesive must be injected in extra amounts for that portion, into a left-side portion in the figure. As such, the attachment strength of the lens unit  51  or the frame  52  may be insufficient, or light transmitted through the adhesive may leak in the image sensor. 
     However, if an adhesive having high shielding property is injected in a large amount in such a manner that the surface of the rigid substrate  53  and the bottom surface of the lens unit  51  (or the frame  52 ) become parallel to each other in a state where the flexible substrate  54  is interposed, the camera module may be configured without forming the groove  51   a  or the groove  52   a.    
       FIG. 6  is a plan view of the camera module  50  illustrated in  FIGS. 5A and 5B , viewed from the upper direction of  FIGS. 5A and 5B . It should be noted that in  FIG. 6 , the lens unit  51  and the frame  52  are not illustrated for easy understanding. 
     As illustrated in  FIG. 6 , a rectangle image sensor  61  is disposed on the almost center of the rigid substrate  53 . It should be noted that in the figure, the front side of the sheet is the imaging surface of the image sensor  61 . As illustrated in the figure, a portion on the left side, in the figure, of the flexible substrate  54  overlaps a portion on the right side, in the figure, of the rigid substrate  53 . In the overlapped portion, the flexible substrate  54  and the rigid substrate  53  are attached, or electrically connected, to each other. 
     Further, as illustrated in  FIG. 6 , the flexible substrate  54  is disposed on the rigid substrate  53  (on the light receiving side of the image sensor  61 ). 
       FIG. 7  is another plan view of the camera module  50  illustrated in  FIGS. 5A and 5B , viewed from the upper direction of  FIGS. 5A and 5B . In the case of  FIG. 7 , an illustration of the frame  52  is added, which is different from  FIG. 6 . 
     As illustrated in  FIG. 7 , a portion on the left side, in the figure, of the flexible substrate  54  overlaps a portion on the right side, in the figure, of the frame  52 , and the flexible substrate  54  is disposed under the frame  52 . Further, the center of the frame  52  is formed as a cavity, whereby the imaging surface of the image sensor  61  is seen. 
       FIG. 8  is a plan view illustrating a detailed exemplary configuration of the frame  52  of  FIG. 7 . This figure is a diagram illustrating the frame  52  seen from the lower direction (rear side of the sheet) of  FIG. 7 , in which the bottom surface of the frame  52  is illustrated. As illustrated in  FIG. 8 , the groove  52   a  is formed on the right side, in the figure, of the frame  52 . It should be noted that the center portion of the frame  52  is formed as a cavity, as described above. 
       FIG. 9  is a cross-sectional view of the frame  52  taken along the alternate long and short dash line A-A′ of  FIG. 8 . As illustrated in the figure, the groove  52   a  is formed on the right side in the figure. 
       FIG. 10  is a plan view illustrating another detailed exemplary configuration of the frame  52  of  FIG. 7 . This figure is a diagram illustrating the frame  52  seen from the lower direction of  FIG. 7 , in which the bottom surface of the frame  52  is illustrated. As illustrated in  FIG. 10 , the groove  52   a  is formed on the right side, in the figure, of the frame  52 . It should be noted that the center portion of the frame  52  is formed as a cavity, as described above. 
     In the example of  FIG. 10 , the groove  52   a  is formed across the rigid substrate  53  from the top to the bottom in the figure, which is different from the case of  FIG. 8 . The groove  52   a  may be formed in this way. 
       FIG. 11  is a cross-sectional view of the frame  52 , taken along the alternate long and short dash line A-A′ of  FIG. 10 . As illustrated in the figure, the groove  52   a  is formed on the right side in the figure. 
     It should be noted that while the case where the groove  52   a  is formed in the frame  52  has been described herein, this also applies to the case where the groove  51   a  is formed in the lens unit  51 . This means that the groove  51   a  may be formed across the entire lens unit  51  from the top to the bottom as in the case of  FIG. 10 , or the groove  51   a  may be formed in such a manner that the upper side and the lower side of the lens unit  51  are left, as in the case of  FIG. 8 . 
     Meanwhile, on the surface of the rigid substrate  53 , a solder resist (SR) serving as an insulation film protecting the circuit pattern, for example, is provided. However, as described with reference to  FIGS. 5A, 5B, 6, 7, 8, 9, 10 and 11 , in the case of attaching the flexible substrate  54  to the surface of the rigid substrate  53  so as to be electrically connected with each other, the SR must be removed beforehand in a portion of the surface of the rigid substrate  53 , in order to connect a connection terminal of the flexible substrate  54  and a connection terminal of the rigid substrate  53  with each other. 
       FIG. 12  is a plan view of the camera module  50  illustrated in  FIGS. 5A and 5B , viewed from the upper direction of  FIGS. 5A and 5B . It should be noted that in  FIG. 12 , the lens unit  51  and the frame  52  are not illustrated for easy understanding. 
     As illustrated in  FIG. 12 , the rectangle image sensor  61  is disposed on the almost center of the rigid substrate  53 . As illustrated in the figure, a portion on the left side, in the figure, of the flexible substrate  54  overlaps a portion on the right side, in the figure, of the rigid substrate  53 . In a portion on the right side, in the figure, of the rigid substrate  53 , the SR is removed and a connection terminal portion  53   a  is formed. 
     Further, even in the flexible substrate  54 , a connection terminal portion is formed in a portion on the left side in the figure. However, in  FIG. 12 , as a connection terminal portion is provided on the rear face of the flexible substrate  54 , it is not illustrated. 
     The connection terminal portion  53   a  of the rigid substrate  53  and the connection terminal portion, not illustrated, of the flexible substrate  54  are provided with connection terminals, respectively, and the connection terminal of the rigid substrate  53  of the rigid substrate  53  and the connection terminal of the flexible substrate  54  are attached, whereby the rigid substrate  53  and the flexible substrate  54  are connected electrically. 
       FIG. 13  is a plan view illustrating the configuration of the flexible substrate  54  and the rigid substrate  53  illustrated in  FIG. 12 , in detail. In the example of the figure, the image sensor  61  is illustrated in more detail. Further, a portion on the left side, in the figure, of the flexible substrate  54  overlaps a portion on the right side, in the figure, of the rigid substrate  53 . In  FIG. 13 , the overlapped portion is illustrated as an overlap width W. 
     The overlap width W is represented as a distance from an end potion of one side (e.g., a side on the right side in  FIG. 13 ) of a square rigid substrate, and in the band region of the overlap width W, the flexible substrate  54  and the rigid substrate  53  are attached to each other in an overlapped manner. In order to reduce the cost of the entire camera module by preventing the connection (attachment) with the flexible substrate  54  from affecting the arrangement of the image sensor  61  and by reducing the area of the expensive flexible substrate, the overlap width W is desirably 2.4 mm or less, for example. 
       FIGS. 14A, 14B, 14C, 14D, 14E and 14F  are diagrams explaining an example of a manufacturing process of a camera module to which the present technology is applied. 
     First, as illustrated in  FIG. 14A , the rigid substrate  53 , on which a component  62  is mounted, is prepared. It should be noted that as described with reference to  FIG. 12 , the SR is removed in a portion on the right side, in the figure, of the rigid substrate  53 , and the connection terminal portion  53   a  is formed. 
     Next, as illustrated in  FIG. 14B , the flexible substrate  54  is attached to the rigid substrate  53 . In this step, the rigid substrate  53  and the flexible substrate  54  are attached to each other in the overlap width W, and the connection terminal disposed in the connection terminal portion  53   a  and the connection terminal of the flexible substrate  54  are attached to thereby be connected electrically. 
     It should be noted that for attaching the rigid substrate  53  and the flexible substrate  54 , solder, an adhesive including solder, ACF, ACP, or the like is used. 
     Next, as illustrated in  FIG. 14C , the image sensor  61  is die-bonded (DB) to the rigid substrate  53 . 
     Then, as illustrated in  FIG. 14D , wire-bonding (WB) is performed between the image sensor  61  and the rigid substrate  53 . In  FIG. 14D , a wire  63  is wire-bonded. 
     Next, as illustrated in  FIG. 14E , an adhesive is applied. In  FIG. 14E , an adhesive  64  is applied to both left and right sides of the rigid substrate  53 . As the adhesive  64  used for adhesion between the rigid substrate  53  and the lens unit  51  (or adhesion between the rigid substrate  53  and the frame  52 ), resin which attenuates light is used. For example, black resin, resin containing filler, or the like is used as the adhesive  64 . 
     Finally, as illustrated in  FIG. 14F , the frame  52  or the lens unit  51  is attached to rigid substrate  53 . It should be note that in the drawing on the left side of  FIG. 14F , the frame  52  is attached to the rigid substrate  53 , and in the drawing on the right side, the lens unit  51  is attached to the rigid substrate  53 . Further, as described above, in order to allow the light condensed by the lens to form an image appropriately on the imaging surface of the image sensor, it is necessary that the parallel degree of the top surface of the lens unit  51  and the imaging surface of the image sensor  61  is 1.5 degrees or less. 
     The camera module to which the present technology is applied is manufactured through this manufacturing process. 
     Meanwhile, in the present technology, the flexible substrate  54  and the rigid substrate  53  are attached in the portion where a portion of the flexible substrate  54  overlaps a portion of the rigid substrate  53  (overlap width). As such, according to the usage conditions of the camera module, it may be desired to improve the break strength of the flexible substrate  54 . 
       FIG. 15  is a diagram explaining another configuration of the flexible substrate  54  in the camera module to which the present technology is applied. This figure is a diagram corresponding to  FIG. 6 , and parts corresponding to those of  FIG. 6  are denoted by the same reference signs. 
     In the example of  FIG. 15 , a reinforced portion  54   a  is provided to the flexible substrate  54 . In this example, the reinforced portions  54   a , extending in a left direction in the figure, are provided to an end on the upper side and an end on the lower side, in the figure, of the flexible substrate  54 . This means that in the flexible substrate  54 , the reinforced portions  54   a , extending in parallel with two sides of the square image sensor  61 , are provided. 
     In addition to the overlap width described above, if the flexible substrate  54  and the rigid substrate  53  are also attached to each other in the reinforced portions  54   a , the area of the attached surface increases, compared with the case of  FIG. 6 . Accordingly, in the case of the configuration of  FIG. 15 , it is possible to improve the break strength of the flexible substrate  54 , compared with the case of  FIG. 6 . 
     Further, as the reinforced portions  54   a  are provided at positions where they are not brought into contact with the image sensor  61 , they do not affect the arrangement of the image sensor  61 . 
     By configuring the flexible substrate  54  as illustrated in  FIG. 15 , it is possible to improve the break strength of the flexible substrate  54  according to the usage conditions of the camera module, for example. 
     Alternatively, the flexible substrate  54  in the camera module to which the present technology is applied may be configured as illustrated in  FIG. 16 . This figure is a diagram corresponding to  FIG. 6 , and the parts corresponding to those of  FIG. 6  are denoted by the same reference signs. 
     In the example of  FIG. 16 , a reinforced portion  54   b  is provided to the flexible substrate  54 . In this example, the reinforced portions  54   b , extending in an up and down direction in the figure, are provided to an end portion on the upper side and an end portion on the lower side, in the figure, of the flexible substrate  54 . This means that in the flexible substrate  54 , the reinforced portions  54   b , extending in parallel with one side of the square image sensor  61 , are provided. 
     In addition to the overlap width described above, if the flexible substrate  54  and the rigid substrate  53  are attached to each other in the reinforced portions  54   b , the area of the attached surface increases, compared with the case of  FIG. 6 . Accordingly, in the case of the configuration of  FIG. 16 , it is possible to improve the break strength of the flexible substrate  54 , compared with the case of  FIG. 6 . 
     Further, as the reinforced portions  54   b  are provided at positions where they are not brought into contact with the image sensor  61 , they do not affect the arrangement of the image sensor  61 . 
     By configuring the flexible substrate  54  as illustrated in  FIG. 16 , it is possible to improve the break strength of the flexible substrate  54  according to the usage conditions of the camera module, for example. 
     Meanwhile, in the embodiment described above, description has been given on the premise that the image sensor  61  and the rigid substrate  53  are wire-bonded, as described with reference to  FIG. 14D . 
     The wire connected with the image sensor  61  bonded on the rigid substrate  53  is electrically connected with the connection terminal disposed on the connection terminal portion  53   a  through the wiring formed on the rigid substrate  53 . Then, the connection terminal of the rigid substrate  53  and the connection terminal of the flexible substrate  54  are attached to each other, whereby the image sensor  61  and the flexible substrate  54  are connected electrically. 
     However, in the case of such a connection, there is a limitation in size reduction of the camera module. This means that when attaching the flexible substrate  54  to the rigid substrate  53 , an overlap width is required as described above, and further, a width for wire bonding is also required between the image sensor  61  and the rigid substrate  53 . Accordingly, the rigid substrate  53  is required to be larger by the width for at least the overlap width and the wire bonding, compared with the image sensor  61 . 
       FIG. 17  is a side view explaining a necessary distance which is a distance from an end of the image sensor  61  to an end of the rigid substrate  53 . As illustrated in  FIG. 17 , a necessary distance is a distance corresponding to an overlap width and a width for wire bonding from an end of the rigid substrate  53 . It should be noted that in practice, a distance considering tolerance and mounting accuracy for preventing an overlap between a wire-bonding pad of the rigid substrate  53  and the connection terminal portion  53   a , in addition to the overlap width and the width for wire bonding, serves as a necessary distance. 
       FIGS. 18A and 18B  are plan views seen from above of  FIG. 17 . In the figure, illustration of the lens unit  51  is omitted for easy understanding. 
     As illustrated in  FIG. 18A , one end of a wire  63  is connected with each of electrode pads (squares in the figure) provided by being aligned in a vertical direction on the right side in the figure and on the left side in the figure of the image sensor  61 . Further, the other end of the wire  63  is connected with each of the electrode pads (squares in the figure) provided by being aligned in a vertical direction on the right side in the figure and on the left side in the figure of the rigid substrate  53 . 
     The electrode pads of the rigid substrate  53  are connected with the connection terminal portions  53   a  through the wiring formed in the rigid substrate  53 , respectively. 
     Then, as illustrated in  FIG. 18B , the flexible substrate  54  is attached, in an overlapped manner, to the connection terminal portions  53   a  of the rigid substrate  53 . At this time, a distance from the end on the right side, in the figure, of the image sensor  61  to the end on the left side, in the figure, of the flexible substrate  54  is a necessary distance. 
     If the rigid substrate  53  is designed so as to have such a necessary distance, it is difficult to reduce the size of the rigid substrate  53 . Consequently, further reduction in size of the camera module is difficult. 
     As such, as illustrated in  FIG. 19 , it is acceptable that the other end of the wire  63 , connected with the electrode pad of the image sensor  61 , is directly connected with the flexible substrate  54 , for example. In the case of the connection as illustrated in  FIG. 19 , as the width for wire bonding can be reduced significantly, the necessary distance can be shortened compared with the case of  FIG. 17 , for example. 
     In the case where the other end of the wire  63 , connected with the electrode pad of the image sensor  61 , is directly connected with the flexible substrate  54 , an electrode pad may be formed by forming an opening by punching a portion of an end portion of the flexible substrate  54  on which wiring is not formed, and embedding metal or the like in the opening, for example. 
       FIGS. 20A and 20B  are diagrams explaining punching of the flexible substrate  54 . 
       FIG. 20A  is a plan view illustrating an example of punching of the flexible substrate  54 . In this example, an end portion on the left side, in the figure, of the flexible substrate  54  is punched to thereby form openings  54   e  aligned in a vertical direction. As illustrated in the figure, the openings  54   e  are formed at positions on the surface of the flexible substrate  54  where wiring  54   f  is not formed. 
     It should be noted that the flexible substrate  54  has a multilayer structure, and is formed such that four layers of substrates are layered. Further, on the uppermost substrate of the flexible substrate  54 , wiring is not formed. In  FIG. 20A , a plurality of lines extending in a horizontal direction in the figure schematically represent that the wiring  54   f  formed in the flexible substrate  54  is seen through the uppermost substrate. 
       FIG. 20B  is a side view corresponding to  FIG. 20A . As illustrated in the figure, the opening  54   e  is formed so as to penetrate from the surface to the bottom face of the flexible substrate  54 , and is formed at a position where wiring  54   g , wiring  54   h , or wiring  54   i  is not formed inside the flexible substrate  54 . This means that all of the layers of the flexible substrate  54  having a multilayer structure are punched to thereby form the opening  54   e.    
     In the opening  54   e , metal is embedded. The metal to be embedded here is Au or a metal having high connectivity with the electrode pad of the image sensor  61 , for example. Further, if the thickness of the flexible substrate  54  is about 100 μm, metal to be embedded may be one in which the surface of a metal such as Ni is plated by Au, for example, rather than a single metal. 
       FIGS. 21A and 21B  are side views explaining a connecting method between the rigid substrate  53  and the flexible substrate  54 . 
     As illustrated in  FIG. 21A , metal is embedded in the opening  54   e  to thereby form an embedded electrode  71 . The embedding method may be a method such as a squeegee printing, for example. The embedded electrode  71  is connected with an electrode pad  72  of the rigid substrate  53  through metal bonding by heat or ultrasonic waves. This means that the embedded electrode  71  is directly welded to the electrode pad  72 . 
     By directly welding the metals in this way, the bonding strength between the rigid substrate  53  and the flexible substrate  54  is enhanced. 
     The electrode pad  72  is electrically connected with wiring  73  inside the rigid substrate  53 . The wiring  73  of the rigid substrate  53  is connected with the wiring  54   i  of the flexible substrate  54 , and the rigid substrate  53  and the flexible substrate  54  are attached to each other with an adhesive such as ACF, an adhesive containing solder (SAM, or the like), or the like. 
     Here, the wiring  73  of the rigid substrate  53  corresponds to a terminal of the connection terminal portion  53   a , for example, and the wiring  54   i  of the flexible substrate  54  corresponding to a terminal of a connection terminal portion of the flexible substrate  54 , for example. 
     Then, as illustrated in  FIG. 21B , the electrode pad  61   a  of the image sensor  61  and the embedded electrode  71  are connected with each other by wire bonding through the wire  63 . Thereby, the electrode pad  61   a  of the image sensor  61  and the wiring  54   i  of the flexible substrate  54  are connected with each other electrically. 
       FIG. 22  is a plan view seen from above of  FIGS. 21A and 21B . 
     As illustrated in  FIG. 22 , one end of a wire is connected with each of the electrode pads provided by being aligned in a vertical direction on the right side in the figure and on the left side in the figure of the image sensor  61 . The flexible substrate  54  is attached so as to overlap the connection terminal portions  53   a  of the rigid substrate  53 , and the other end of the wire  63 , connected with the electrode pad  61   a  on the right side in the figure, is connected with the embedded electrode  71  embedded in the flexible substrate  54 . In this case, a distance from the end on the right side, in the figure, of the image sensor  61  to the end on the left side, in the figure, of the flexible substrate  54  is a necessary distance. 
     It should be noted that in  FIG. 22 , the electrode pads on the left side in the figure of the image sensor  61  are connected with the electrode pads of the rigid substrate  53  through wires. 
     With this configuration, as the width for wire bonding can be reduced significantly, the necessary distance can be shortened, compared with the case of  FIGS. 18A and 18B , for example. Thereby, it is possible to further reduce the size of the camera module. 
     In the example described above with reference to  FIGS. 21A and 21B , while description has been given on the example of the case where the embedded electrode  71  is embedded in the opening  54   e  of the flexible substrate  54  by a method such as squeegee printing, it is possible to form a stud bump, instead of embedding the embedded electrode  71 . 
       FIGS. 23A and 23B  are side views explaining another example of a connecting method between the rigid substrate  53  and the flexible substrate  54 . 
     As illustrated in  FIG. 23A , a stud bump  81  is formed in the opening  54   e . The stud bump  81  is connected with the electrode pad  72  of the rigid substrate  53  through metal bonding by heat or ultrasonic waves. This means that the stud bump  81  is directly welded to the electrode pad  72 . 
     By directly welding the metals in this way, the bonding strength between the rigid substrate  53  and the flexible substrate  54  is enhanced. 
     The electrode pad  72  is electrically connected with the wiring  73  inside the rigid substrate  53 . The wiring  73  of the rigid substrate  53  is connected with the wiring  54   i  of the flexible substrate  54 , and the rigid substrate  53  and the flexible substrate  54  are attached to each other with an adhesive of ACF, for example. 
     Then, as illustrated in  FIG. 23B , the electrode pad  61   a  of the image sensor  61  and the stud bump  81  are connected by wire bonding through the wire  63 . Thereby, the electrode pad  61   a  of the image sensor  61  and the wiring  54   i  of the flexible substrate  54  are electrically connected. 
     It should be noted that after the stud bump  81  is formed, the rigid substrate  53  and the flexible substrate  54  may be overlapped and attached to each other by aligning the position of the stud bump  81  and the position of the opening  54   e.    
     Meanwhile, in the embodiment described above with reference to  FIGS. 21A, 21B, 22, 23A and 23B , the embedded electrode  71  or the stud bump  81  formed in the opening  54   e  of the flexible substrate  54  is connected with the electrode pad  72  of the rigid substrate  53 , and is electrically connected with the wiring  73  inside the rigid substrate  53 . In this case, a signal output from the image sensor  61  is transmitted from the flexible substrate  54  through the rigid substrate  53  once, and is transmitted to the flexible substrate  54  again. 
     However, if a signal output from the image sensor  61  is transmitted to the flexible substrate  54  and is directly transmitted inside the flexible substrate  54 , the wiring in the rigid substrate  53  can be further simplified. Further, as a signal output from the image sensor  61  is transmitted not through the connection terminal portion  53   a  of the rigid substrate  53 , it is possible to reduce impedance associated with connection of the terminals, and further, to reduce the number of terminals in the connection terminal portions  53   a.    
       FIG. 24  is a side view explaining still another example of a connecting method between the rigid substrate  53  and the flexible substrate  54 . 
     In the example of  FIG. 24 , a pad  85  is formed on the upper side in the figure of the flexible substrate  54 . The pad  85  is wire-bonded to the electrode pad  61   a  of the image sensor  61  through the wire  63 , and a signal output from the image sensor  61  is transmitted inside the flexible substrate  54  through the wiring  54   j  and the like. 
       FIG. 25 , which is part of  FIG. 24 , is a diagram illustrating an enlarged connecting portion between the flexible substrate  54  and the rigid substrate  53 . 
     As illustrated in  FIG. 25 , a signal supplied through the wire  63  connected with the pad  85  is transmitted inside the flexible substrate  54  through the wiring  54   j  and the like, not through the rigid substrate  53 . On the other hand, a signal transmitted through the wiring and the like in the rigid substrate  53  is transmitted to the flexible substrate  54 , by the wiring  73  (terminal of the connection terminal portion  53   a ) of the rigid substrate  53  and the wiring  54   i  (terminal of the connection terminal portion) of the flexible substrate being connected with each other with ACF, an adhesive containing solder, or the like. 
     As illustrated in  FIG. 25 , in the case of forming the pad  85 , in the flexible substrate  54  having a multilayer structure, the pad  85  may be formed by forming an opening by punching an end portion of the uppermost layer, and embedding metal in the opening, for example. In this step, metal is embedded in the opening by squeegee printing or the like. 
       FIGS. 26A and 26B  are diagrams explaining punching of the flexible substrate  54  when forming the pad  85  illustrated in  FIG. 25 . 
       FIG. 26A  is a plan view illustrating an example of punching of the flexible substrate  54 . In this example, an end portion on the left side, in the figure, of an uppermost layer  54 - 1  of the flexible substrate  54  is punched to thereby form openings  54 - 1   e  aligned in a vertical direction. 
       FIG. 26B  is a side view corresponding to  FIG. 26A . As illustrated in the figure, the opening  54 - 1   e  is formed so as to penetrate only the uppermost layer  54 - 1  of the flexible substrate  54 . 
       FIGS. 27A and 27B  are diagrams illustrating a configuration of the entire flexible substrate  54  configured to include the uppermost layer  54 - 1  illustrated in  FIG. 26A  and  FIG. 26B . 
       FIG. 27A  is a plan view of the entire flexible substrate  54  configured to include the uppermost layer  54 - 1 . In this example, the flexible substrate  54  has a four-layer structure. In  FIG. 27A , the uppermost layer  54 - 1  adheres to the other three layers, and a plurality of lines extending in a horizontal direction in the figure schematically represent that the wiring  54   f  formed in the flexible substrate  54  is seen through the uppermost substrate. 
       FIG. 27B  is a side view corresponding to  FIG. 27A . As illustrated in the figure, the opening  54 - 1   e  only penetrates the uppermost layer  54 - 1  of the flexible substrate  54 , and no opening is formed in the lower layers. 
     With this configuration, as the width for wire bonding can be reduced significantly, the necessary distance can be shortened compared with the case of  FIGS. 18A and 18B , for example. Thereby, it is possible to further reduce the size of the camera module. 
     Further, as a signal output from the image sensor  61  is transmitted to the flexible substrate  54  and is directly transmitted inside the flexible substrate  54 , the wiring in the rigid substrate  53  can be further simplified. 
     Further, as a signal output from the image sensor  61  is transmitted not through the connection terminal portion  53   a  of the rigid substrate  53 , it is possible to reduce impedance associated with connection of the terminal, and further, to reduce the number of terminals in the connection terminal portion  53   a.    
     Alternatively, in the flexible substrate  54 , the pad  85  as illustrated in  FIG. 25  and the embedded electrode  71  as illustrated in  FIGS. 21A and 21B  (or the stud bump  81  as illustrated in  FIGS. 23A and 23B ) may be formed so as to be provided together. 
     As described above, in the flexible substrate  54 , if the pad  85  is formed, impedance associated with connection of the terminal can be reduced. On the other hand, in order to improve bonding strength between the rigid substrate  53  and the flexible substrate  54 , it is effective to form the embedded electrode  71  or the stud bump  81 . 
     For example, a wire for a signal having high resistance to noise, among the signals transmitted from and received by the image sensor  61 , is allowed to be connected with the embedded electrode  71  or the stud bump  81 , and the other wires for a signal are allowed to be connected to the pad  85 , for example. In this way, if the pad  85  and the embedded electrode  71  (or stud bump  81 ) are provided together, it is possible to improve the bonding strength between the rigid substrate  53  and the flexible substrate  54  without lowering the SI (Signal Integrity). 
     In the example described above with reference to  FIGS. 24, 25, 26A, 26B, 27A and 27B , description has been given on the example in which an opening is formed in the flexible substrate  54 , whereby the embedded electrode  71 , the stud bump  81 , or the pad  85  is formed and wire-bonding is performed. However, it is also acceptable to perform wire bonding to the electrode pad provided on the surface of the uppermost layer  54 - 1  of the flexible substrate  54 , without forming an opening in the flexible substrate  54 . 
     Further, when performing wire bonding to the electrode pad provided on the surface of the uppermost layer  54 - 1  of the flexible substrate  54 , a form of on bump bonding (ball stitch on ball bonding) may be taken. On bump bonding is a form in which a bump is formed on an electrode pad in advance, and second bonding is performed on the bump. 
     Meanwhile, the embodiment described above with reference to  FIGS. 19, 20A, 20B   21 A,  21 B,  22 ,  23 A,  23 B  24 ,  25 ,  26 A,  26 B,  27 A and  27 B has described an example in which the other end of the wire  63 , connected with the electrode pad of the image sensor  61 , is directly connected with the flexible substrate  54 , whereby the size of the camera module is reduced. 
     However, it is also possible to reduce the size of the camera module by adopting another method. For example, it is possible to reduce the size of the camera module by making the electrode pads aligned in a vertical direction of the rigid substrate  53  and the terminals of the connection terminal portion  53   a  of the rigid substrate  53  common. 
     As described with reference to  FIG. 18A , one end of the wire  63  is connected with each of the electrode pads (squares in the figure) provided to be aligned in a vertical direction on the right side in the figure and on the left side in the figure of the image sensor  61 . Further, the other end of the wire  63  is connected with each of the electrode pads (squares in the figure) provided to be aligned in a vertical direction on the right side in the figure and on the left side in the figure of the rigid substrate  53 . Here, each of the electrode pads provided to be aligned on the right side, in the figure, of the rigid substrate is an electrode pad  53   b.    
       FIG. 28  is an enlarged view of part of the electrode pads  53   b  and the connection terminal portion  53   a  in  FIG. 18A .  FIG. 28  illustrates electrode pads  53   b - 1  to  53   b - 5 , and terminals  53   a - 1  to  53   a - 5  in the connection terminal portion  53   a.    
     The electrode pad  53   b - 1  is connected with the wiring inside (in the lower layer of) the rigid substrate  53  through a via V 11 , and is connected with a via, not shown, through the wiring, to thereby be electrically connected with a terminal connected with the via. Further, the terminal  53   a - 1  is connected with the wiring inside (in the lower layer of) the rigid substrate  53  through a via V 21 , and is connected with an electrode pad or the like, not shown, through the wiring. 
     The electrode pad  53   b - 2  is directly connected with the terminal  53   a - 2  through the wiring in the surface layer of the rigid substrate  53  to thereby be electrically connected with the terminal  53   a - 2 . 
     The electrode pad  53   b - 3  is directly connected with the terminal  53   a - 3  through the wiring in the surface layer of the rigid substrate  53  to thereby be electrically connected with the terminal  53   a - 3 . 
     The electrode pad  53   b - 4  is connected with the wiring inside (in the lower layer of) the rigid substrate  53  through a via V 12 , and is connected with a via, not shown, through the wiring, to thereby be electrically connected with a terminal connected with the via. Further, the terminal  53   a - 4  is connected with the wiring inside (in the lower layer of) the rigid substrate  53  through a via V 22 , and is connected with an electrode pad or the like, not shown, through the wiring. 
     The electrode pad  53   b - 5  is directly connected with the terminal  53   a - 3  through the wiring in the surface layer of the rigid substrate  53  to thereby be electrically connected with the terminal  53   a - 5 . 
     In this way, by passing through the wiring inside (in the lower layer of) the rigid substrate  53  or the wiring in the surface layer of the rigid substrate  53 , a distance between the electrode pad  53   b  and the connection terminal portion  53   a  must be longer. Accordingly, a necessary distance, which is a distance corresponding to the overlap width and the width for wire bonding, from an end of the rigid substrate  53 , also becomes longer. 
     As such, as illustrated in  FIG. 29 , the electrode pads provided to be aligned in a vertical direction of the rigid substrate  53  and the terminals in the connection terminal portion  53   a  are made common, for example. In the example of  FIG. 29 , the electrode pads provided at positions near the connection terminal portion  53   a  and aligned in a vertical direction on the right side, in the figure, of the rigid substrate  53 , are made common to the terminals in the connection terminal portion  53   a.    
     It should be noted that in  FIG. 29 , the terminals in the connection terminal portion  53   a  are classified into three, in which a terminal group provided on the upper side in the figure is a terminal group Tm 1 , a terminal group provided in the middle in the figure is a terminal group Tm 2 , and a terminal group provided on the lower side in the figure is a terminal group Tm 3 . Among the terminal groups Tm 1  to Tm 3 , a terminal group which is made common to the electrode pads provided to be aligned in a vertical direction on the right side in the figure of the rigid substrate  53  is the terminal group Tm 2 . The terminal group Tm 1  and the terminal group Tm 3  are not made common to the electrode pads provided to be aligned in a vertical direction on the right side in the figure of the rigid substrate  53 . 
       FIG. 30  is an enlarged view of part of the terminal group Tm 2  in  FIG. 29 .  FIG. 30  illustrates the terminals  53   a - 1  to  53   a - 5  in the connection terminal portion  53   a.    
     The terminals  53   a - 1  to  53   a - 5  in  FIG. 30  are terminals having larger areas compared with the case of the terminals  53   a - 1  to  53   a - 5  in  FIG. 28 . To each of the terminals  53   a - 1  to  53   a - 5 , the other end of the wire  63 , in which one end thereof is connected with the electrode pad of the image sensor  61 , is wire bonded. Further, to each of the terminals  53   a - 1  to  53   a - 5 , a connection terminal of the flexible substrate  54  is attached. 
     Further, the terminal  53   a - 5  is configured to be connected with the wiring inside (in the lower layer of) the rigid substrate  53  through a via V 23 . The terminal  53   a - 5  is, for example, a terminal of a power source or GND, and is connected with the power source or the GND through the wiring inside (in the lower layer of) the rigid substrate  53 . 
       FIG. 31  is a cross-sectional view corresponding to  FIG. 18B , and is a cross-sectional view taken along a line in a horizontal direction in the figure passing through the center of the image sensor  61  in  FIG. 18B . As illustrated in the figure, one end of the wire  63  is connected with the electrode pad on the image sensor  61 , and the other end of the wire  63  is connected with the electrode pad  53   b  of the rigid substrate  53 . 
       FIG. 32  is a cross-sectional view corresponding to  FIG. 29 , and is a cross-sectional view taken along a line in a horizontal direction in the figure passing through the center of the image sensor  61  in  FIG. 18B . As illustrated in the figure, one end of the wire  63  is connected with the electrode pad on the image sensor  61 , and the other end of the wire  63  is connected with the terminal in the connection terminal portion  53   a  on the rigid substrate  53 . Further, in the case of  FIG. 32 , the electrode pads (electrode pad  53   b  in  FIG. 31 ) provided to be aligned on the right side in the figure of the rigid substrate  53  are made common to the terminals of the connection terminal portion  53   a.    
     By adopting the configuration illustrated in  FIG. 32 , it is possible to shorten the length in a horizontal direction in the figure of the rigid substrate  53 . This means that a length L 22  in a horizontal direction in the figure of the rigid substrate  53 , in the configuration illustrated in  FIG. 32 , is shorter than a length L 21  in a horizontal direction in the figure of the rigid substrate  53  in the configuration illustrated in  FIG. 31 . As such, a necessary distance which is a distance from an end of the rigid substrate  53  corresponding to the overlap width and the width for wire bonding, can also be shortened. 
     In this way, according to the present technology, the size of a camera module can be further reduced. 
     As described above, a camera module to which the present technology is applied is to be installed in an electronic device such as a mobile telephone, a smartphone, or the like.  FIG. 33  is a block diagram illustrating an exemplary inner configuration according to an embodiment of a mobile telephone to which the present technology is applied. 
     In a mobile telephone  100  illustrated in  FIG. 33 , a communication antenna  112  is a built-in antenna, for example, and performs transmission and reception of signal wave for telephone calls and packet communications such as e-mails. A communication circuit  111  performs frequency conversion, modulation, and demodulation of transmission/reception signals. 
     A speaker  120  is a speaker for receiving voices provided in the mobile telephone  100 , or a speaker for outputting ringer (incoming calls), alarm sound, and the like, and converts sound signals supplied from a control and arithmetic unit  110  into acoustic waves and outputs them to the air. 
     A microphone  121  is a microphone for voice transmission and collection of outside sound, and converts acoustic waves to sound signals and transmits the sound signals to the control and arithmetic unit  110 . 
     A display unit  113  includes a display device such as a liquid crystal display or an organic EL display, and a display drive circuit of the display, and displays various types of characters and images such as e-mails, for example, on the display by image signals supplied from the control and arithmetic unit  110 , and if captured images are supplied from the camera unit  124 , displays the captured images. 
     An operation unit  114  is configured of various keys such as numeric keys, a call key, an end/power key, and the like provided on the casing of the mobile telephone  100 , various operators such as a cross key, a shutter button, and a horizontal photographing mode switch, and an operation signal generator which generates operation signals when those operators are operated. It should be noted that if the mobile telephone  100  has a touch panel, the touch panel is also included in the operation unit  114 . 
     A camera unit  124  is a function block equivalent to the camera module  50  described above with reference to  FIGS. 4 to 16 . This means that as the camera unit  124 , the camera module  50  to which the present technology is applied is disposed. An image signal captured by the camera unit  124  is applied with various types of image processing by the control and arithmetic unit  110 , and then, is displayed on the display screen of the display unit  113 , is compressed and stored in a memory unit  116 , or the like. 
     The memory unit  116  includes a built-in memory provided inside the terminal, and a detachable card memory which stores so-called SIM (Subscriber Identity Module) information and the like. The built-in memory includes a ROM (Read Only Memory) and a RAM (Random Access Memory). A ROM is configured of a rewritable ROM such as a NAND-type flash memory or an EEPROM (Electrically Erasable Programmable Read-Only Memory). In the ROM, an OS (Operating System) program, a control program for controlling the respective units by the control and arithmetic unit  110 , various application programs, dictionary data, sound data such as incoming call sound and key operation sound, image data captured by the camera unit  124 , and the like are stored. 
     A RAM stores data from time to time, as a work region when the control and arithmetic unit  110  performs various types of data processing. 
     The control and arithmetic unit  110  is configured of a CPU (central processing unit), and performs control of communications in the communication circuit  111 , sound processing and control thereof, image processing and control thereof, control of image capturing by the camera unit  124 , control of other various types of signal processing and respective units, and the like. Further, the control and arithmetic unit  110  performs execution of various types of control programs and application programs stored in the memory unit  116 , and various types of data processing associated therewith, and the like. 
     In addition, although not shown, components provided to a typical mobile telephone  100  are also provided, which includes a current position detection unit using GPS (Global Positioning System) satellite waves, a contactless communication unit which performs contactless communications used in a contactless IC card, and the like, a power management IC unit which controls a battery for supplying power to respective units and the power thereof, a slot for external memory, a receiving tuner for digital broadcasting, an AV codec unit, and the like. 
     While an example in which a camera module, to which the present technology is applied, is installed in a mobile telephone has been described herein, a camera module, to which the present technology is applied, can be installed in various types of electronic devices such as a smartphone and a tablet device. 
     Further, the embodiment of the present technology is not limited to the above-described embodiment, and various changes can be made within the scope of the gist of the present technology. 
     It should be noted that the present technology may also be configured as described below. 
     (1) 
     A camera module including: 
     a lens unit that stores a lens that condenses light on a light receiving surface of an image sensor; 
     a rigid substrate on which the image sensor is disposed; and 
     a flexible substrate electrically connected with the rigid substrate, wherein 
     in a case where the light receiving surface of the image sensor locates at the top, the lens unit, the flexible substrate, and the rigid substrate are disposed in this order from the top. 
     (2) 
     The camera module according to (1), wherein 
     in the rigid substrate of a square shape, 
     in an overlap region of a band shape having a predetermined distance from an end of one side of the square, the rigid substrate is disposed to overlap a portion of the flexible substrate, and the rigid substrate and the flexible substrate are attached to each other. 
     (3) 
     The camera module according to (2), wherein the overlap region is a band-shaped region having a width of 2.4 mm or less. 
     (4) 
     The camera module according to (2), wherein 
     in the flexible substrate, 
     besides the overlap region, a reinforced region in which the flexible substrate overlaps the rigid substrate is provided. 
     (5) 
     The camera module according to (4), wherein 
     the reinforced region is provided to extend in parallel with two sides of the image sensor of the square shape. 
     (6) 
     The camera module according to (4), wherein 
     the reinforced region is provided to extend in parallel with one side of the image sensor of the square shape. 
     (7) 
     The camera module according to any of (1) to (6), wherein 
     in the rigid substrate of a square shape, 
     a solder resist is removed in a band-shaped region having a predetermined distance from an end of one side of the square. 
     (8) 
     The camera module according to any of (1) to (7), wherein 
     a groove for accommodating an end portion of the flexible substrate is formed in the lens unit. 
     (9) 
     The camera module according to any of (1) to (7), wherein 
     a frame is further provided between the lens unit and the flexible substrate. 
     (10) 
     The camera module according to (9), wherein 
     a groove for accommodating an end portion of the flexible substrate is formed in the frame. 
     (11) 
     The camera module according to any of (1) to (10), wherein 
     an electrode pad of the image sensor and an embedded electrode provided in the flexible substrate are connected with each other by wire bonding, and 
     a signal output from the electrode pad of the image sensor is transmitted to the rigid substrate through the embedded electrode. 
     (12) 
     The camera module according to (11), wherein 
     the embedded electrode is formed by punching all layers of the flexible substrate having a multilayer structure to thereby form an opening, and embedding metal in the opening. 
     (13) 
     The camera module according to any of (1) to (10), wherein 
     the electrode pad is formed by punching an uppermost layer of the flexible substrate having a multilayer structure to thereby form an opening, and embedding metal in the opening, and 
     an electrode pad of the image sensor and the electrode pad provided in the flexible substrate are connected with each other by wire bonding. 
     (14) 
     The camera module according to any of (1) to (10), wherein 
     an electrode pad of the image sensor and a stud bump protruding on the rigid substrate are connected by wire bonding. 
     (15) 
     The camera module according to (14), wherein 
     an opening is formed by punching all layers of the flexible substrate having a multilayer structure, and 
     the stud bump is formed on an electrode pad which is on the rigid substrate and is located at a position corresponding to the opening. 
     (16) 
     The camera module according to any of (1) to (10), wherein 
     in the flexible substrate having a multilayer structure, an opening formed by punching all layers and an opening formed by punching an uppermost layer of the flexible substrate are provided in a region connected with an electrode pad of the image sensor by wire bonding. 
     (17) 
     The camera module according to (1), wherein an electrode pad of the image sensor and an electrode pad of the rigid substrate are connected with each other by wire bonding, and 
     the electrode pad of the rigid substrate is made common to a connection terminal provided on the rigid substrate for electrically connecting the flexible substrate. 
     (18) 
     The camera module according to (17), wherein 
     among the electrode pads and the connection terminals of the rigid substrate provided on a plurality of sides of the rigid substrate configured in a rectangle shape, only an electrode pad and a connection terminal provided on one side of the rigid substrate are made common. 
     (19) 
     The camera module according to (18), wherein 
     among the connection terminals of the rigid substrate provided on the one side, only a connection terminal in a center portion of the side is made common to the electrode pad. 
     (20) 
     The camera module according to (17), wherein 
     the connection terminal, made common to the electrode pad, is connected with wiring inside the rigid substrate through a via. 
     (21) 
     A camera module manufactured by a method including the steps of: 
     disposing a rigid substrate; 
     connecting a flexible substrate with the rigid substrate; and 
     disposing a lens unit on the rigid substrate, the lens unit storing a lens that condenses light on a light receiving surface of the image sensor, wherein 
     in the step of connecting the flexible substrate with the rigid substrate, in the rigid substrate of a square shape, in an overlap region of a band shape having a predetermined distance from an end of one side of the square, the rigid substrate is disposed to overlap a portion of the flexible substrate, and the rigid substrate and the flexible substrate are attached to each other. 
     (22) 
     An electronic device including 
     a camera module including:
         a lens unit that stores a lens that condenses light on a light receiving surface of an image sensor;   a rigid substrate on which the image sensor is disposed; and   a flexible substrate electrically connected with the rigid substrate, wherein       

     in a case where the light receiving surface of the image sensor locates at the top, the lens unit, the flexible substrate, and the rigid substrate are disposed in this order from the top. 
     REFERENCE SIGNS LIST 
     
         
           50  Camera module 
           51  Lens unit 
           52  Frame 
           53  Rigid substrate 
           54  Flexible substrate 
           54   e  Opening 
           61  Image sensor 
           61   a  Electrode pad 
           63  Wire 
           71  Embedded electrode 
           72  Electrode pad 
           81  Stud bump 
           85  Pad 
           100  Mobile telephone 
           124  Camera unit