Patent Publication Number: US-2023164918-A1

Title: Image pickup apparatus

Description:
BACKGROUND 
     Field 
     The present disclosure relates to an image pickup apparatus having a structure for dissipating heat generated from a heat source. 
     Description of the Related Art 
     With a recent demand for downsizing of electronic apparatuses, mounted components in the apparatuses have been remarkably downsized and densified. 
     Meanwhile, a demand for higher functionality of an image pickup apparatus, in particular, higher performance of a moving image function has been increasing, and the amount of heat generation of the apparatus has been on the rise. 
     At the time of capturing a moving image in a high-temperature environment, a temperature rise in the image pickup apparatus is likely to cause a malfunction or performance degradation of a mounted component, and eventually cause a breakdown of the image pickup apparatus. 
     To address this, a heat dissipation structure using forced air cooling with a fan or a heat conduction member is used in a case where the amount of heat dissipation using natural heat dissipation is not sufficient with respect to the amount of heat generation of the image pickup apparatus. 
     Japanese Patent Application Laid-Open No. 2020-030393 discusses an apparatus in which a heat conduction member is connected to a movable image sensor to cool the image sensor. 
     In recent years, an image pickup apparatus that performs shake correction by moving an image sensor in a direction orthogonal to an optical axis direction has been widespread in order to improve image quality. 
     Such an image pickup apparatus that performs shake correction is also desirable to provide sufficient heat dissipation because heat generated in the image sensor affects image quality at the time of driving a shake correction mechanism, continuously capturing images, or capturing a moving image. 
     In the apparatus discussed in Japanese Patent Application Laid-Open No. 2020-030393, however, the heat conduction member is physically connected to the movable image sensor, and thus there is an issue where the operation of the image sensor is obstructed. 
     SUMMARY 
     The present disclosure is directed to an image pickup apparatus that achieves satisfactory heat dissipation performance without obstructing the operation of a movable image sensor. 
     According to an aspect of the present disclosure, an image pickup apparatus includes an image sensor configured to move within a movable range of the image sensor in a direction different from an optical axis direction, a first circuit board on which the image sensor is mounted, a second circuit board facing the first circuit board, a first flexible board configured to electrically connect the first circuit board and the second circuit board, and a fan, wherein the first flexible board includes a bent portion that is located closest to a side of the first flexible board connected to the first circuit board, wherein the first flexible board is bent in an area overlapping the movable range of the image sensor in the optical axis direction, and wherein, as viewed from the optical axis direction, an inner surface of the bent portion of the first flexible board is disposed to be outside a range of a blowing direction of an airflow discharged from a vent of the fan. 
     Further features of the present disclosure will become apparent from the following description of exemplary embodiments with reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a rear exploded perspective view of a digital camera according to a first exemplary embodiment of the present disclosure. 
         FIGS.  2 A and  2 B  are a front exploded perspective view and a rear exploded perspective view, respectively, of an image sensor unit according to the first exemplary embodiment. 
         FIGS.  3 A and  3 B  are a rear view and a rear schematic view, respectively, of the image sensor unit and a heat dissipation fan according to the first exemplary embodiment. 
         FIG.  4    is a rear perspective view of the image sensor unit and the heat dissipation fan according to the first exemplary embodiment. 
         FIGS.  5 A,  5 B,  5 C, and  5 D  are an A-A section view, a B-B section view, a C-C section view, and a rear view, respectively, of the image sensor unit and the heat dissipation fan according to the first exemplary embodiment. 
         FIG.  6 A  is a side view of the image sensor unit according to the first exemplary embodiment, and  FIG.  6 B  is a D-D section view of the image sensor unit and the heat dissipation fan according to the first exemplary embodiment. 
         FIGS.  7 A and  7 B  are an A-A section view and a B-B section view, respectively, of an image sensor unit according to a second exemplary embodiment of the present disclosure, and  FIG.  7 C  is a rear view of the image sensor unit and a heat dissipation fan according to the second exemplary embodiment. 
         FIG.  8 A  is a side view of the image sensor unit according to the second exemplary embodiment, and  FIG.  8 B  is a C-C section view of the image sensor unit and the heat dissipation fan according to the second exemplary embodiment. 
         FIGS.  9 A and  9 B  are rear perspective views of an image sensor unit and a heat dissipation fan according to a third exemplary embodiment of the present disclosure. 
         FIGS.  10 A,  10 B,  10 C, and  10 D  are an A-A section view, a B-B section view, a C-C section view, and a rear view, respectively, of the image sensor unit and the heat dissipation fan according to the third exemplary embodiment. 
         FIG.  11    is a block diagram according to an exemplary embodiment of the present disclosure. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     Exemplary embodiments of the technique of the present disclosure will be described in detail below with reference to the drawings. 
     The dimensions, materials, and shapes of components to be described below and the relative arrangements and the like of the components may be modified as appropriate depending on the configuration of an apparatus to which an exemplary embodiment of the present disclosure is applied and various conditions. 
     Thus, the following description is not intended to limit the scope of the disclosure. 
     In particular, a well-known technique or a publicly known technique in the technical field concerned can be applied to a configuration or a process that is not illustrated in the drawings or not described in the specification. Besides, a repeated description can be omitted. 
     In the drawings, the same reference numerals are used to indicate the identical or functionally similar components. 
     &lt;Rear Exploded Perspective View of Digital Camera&gt; 
       FIG.  1    is a rear exploded perspective view of a digital camera  100  that is an image pickup apparatus according to a first exemplary embodiment of the present disclosure. 
     The digital camera  100  includes a mount unit  102   a , a rear cover  101 , a front base  102 , a top cover  103 , a bottom cover  104 , and a side cover  105 , as illustrated in  FIG.  1   . 
     An image sensor unit  106  having an image blur correction mechanism, a main board  107 , a shutter  108 , a viewfinder  109 , and a chassis  110  are disposed inside the digital camera  100 . 
     The image sensor unit  106  includes a movable unit  114  (see  FIG.  2 A ) and a fixing unit, and is disposed perpendicularly to an optical axis. The movable unit  114  includes an image sensor  115  (see  FIG.  2 A ). 
     The front base  102  is formed of, for example, a magnesium die cast or resin, and includes the mount unit  102   a  for mounting an interchangeable lens. 
     The main board  107  is formed of a multilayer board, and electronic components are mounted on both sides thereof. The main board  107  is fixed to the front base  102  and the chassis  110  made of metal by screws. 
     The main board  107  is mounted with a control integrated circuit (IC)  107   a  for controlling an image pickup signal and the like, a storage medium connector  107   b  for housing an external storage medium, and an external communication terminal  107   c  for connecting a connection cable to an external apparatus. 
     The external communication terminal  107   c  is covered by a terminal cover  105   a.    
     Among the components of the digital camera  100 , the image sensor unit  106 , in particular, has high power consumption and also generates a large amount of heat, thereby causing a significant temperature rise. 
     The maximum duration that the digital camera  100  can perform imaging is limited by the operation guarantee temperature of each of the components. 
     To maintain the maximum imaging duration as long as possible, it is desirable to prevent the operation guarantee temperature from being exceeded, by releasing the heat of the image sensor unit  106  which is a heat source. 
     The image sensor unit  106  is fixed to the front base  102  by screws, so that the heat of the image sensor unit  106  is released to the front base  102 . 
     A heat dissipation fan  130  is disposed near the image sensor unit  106  to have a blowing direction perpendicular to the optical axis, so that air passing behind the image sensor unit  106 , which is a heat source, prevents the image sensor unit  106  from becoming locally hot (which will be described in detail below). 
     In the present exemplary embodiment, the heat dissipation fan  130  uses a centrifugal fan as an air blowing unit, but is not limited thereto, and may use, for example, an axial fan as long as the purpose can be achieved. 
     Further, in the present exemplary embodiment, the blowing direction of the heat dissipation fan  130  is perpendicular to the optical axis, but is not limited thereto. The blowing direction may not necessarily be perpendicular to the optical axis if an airflow from the heat dissipation fan  130  directly hits the image sensor unit  106 . 
     The main board  107  is also a heat source, and thus the heat dissipation fan  130  is disposed so that a vent  131  thereof (see  FIG.  3 A ) is directed to an area between the image sensor unit  106  and the main board  107  to blow air into the area. 
     This makes it possible to produce a heat dissipation effect for a plurality of heat sources. 
     However, the image sensor unit  106  including the movable unit  114  has fewer heat dissipation paths, and thus it is advantageous, in terms of heat dissipation, that the vent  131  of the heat dissipation fan  130  is located at a position closer to the image sensor unit  106  than to the main board  107 . 
     &lt;Image Sensor Unit&gt; 
     Details of the image sensor unit  106  will be described with reference to  FIGS.  2 A and  2 B .  FIGS.  2 A and  2 B  are a front exploded perspective view and a rear exploded perspective view, respectively, of the image sensor unit  106 . 
     The movable unit  114  includes a coil portion  116  in which a coil for moving the image sensor  115  and a Hall element are disposed and which is held by a sensor holder  117 . 
     Three magnets  118  are held in a drive mechanism  113 , and the movable unit  114  is attracted and held by the magnets  118 . 
     A ball (not illustrated) is held in a ball holding portion  117   a  of the sensor holder  117  and located between the movable unit  114  and the drive mechanism  113 . 
     The movable unit  114  can be moved by changing the amount of energization of the coil portion  116 . 
     Shake correction can be performed by moving the movable unit  114  in a direction that cancels out the shake of the main body of the digital camera  100 . 
     The image sensor  115  is mounted on an image pickup board  115   a . More specifically, a sensor chip (not illustrated) is bonded to the image pickup board  115   a  on which an image pickup circuit is mounted, and is electrically connected onto the image pickup board  115   a  by wire bonding. 
     The image sensor  115  and the sensor holder  117  are fixed to each other by an adhesive. 
     Elements  115   b  such as a condenser, a resistor, and a regulator of the image pickup circuit are mounted on a back surface of the image pickup board  115   a  that is opposite to the surface of the image pickup board  115   a  to which the sensor chip is bonded. 
     The image sensor unit  106  and the main board  107  are electrically connected using a flexible wiring board. 
     On an image pickup signal flexible board  111  (see  FIG.  4   ), wiring for an image pickup signal output from the image sensor  115  and a control signal for driving the image sensor  115  is formed, and the signals are transmitted to the control IC  107   a  on the main board  107 . 
     An image pickup power flexible board  112  (see  FIG.  4   ) supplies power for driving the image sensor  115 . A board-to-board connector is used to connect the image pickup board  115   a  and each of the flexible boards  111  and  112 . 
     &lt;Rear View and Rear Schematic View of Heat Dissipation Fan and Image Sensor Unit&gt; 
       FIGS.  3 A and  3 B  are a rear view and a rear schematic view of the heat dissipation fan  130  and the image sensor unit  106 , respectively. 
     Referring to  FIGS.  3 A and  3 B , the movement of the movable unit  114  of the image sensor unit  106  and the positional relationship between the movable unit  114  and the heat dissipation fan  130  will be described. 
     The movable unit  114  is movable perpendicularly to the optical axis within a movable range  114   a . A range in which the movable unit  114  is always present even if moved is indicated by a range  114   b.    
     This is the range in which the movable unit  114  is present whichever position the movable unit  114  is moved to within the movable range  114   a.    
     Next, placement of the heat dissipation fan  130  will be described. The heat dissipation fan  130  blows air so that the air runs behind the image sensor unit  106  as described above. 
     More specifically, the vent  131  of the heat dissipation fan  130  is directed so that the air is blown to the range  114   b  where the movable unit  114  is always present even if moved. 
     In  FIG.  3 B , a blowing range  131   a  indicates a range of the blowing direction. Because the blowing range  131   a  is within the range  114   b , a heat dissipation effect can be obtained whichever position the movable unit  114 , which is a heat source of the image sensor unit  106 , is moved to. 
     In addition, the heat dissipation fan  130  is not physically connected to the movable unit  114 , and thus it is possible to produce the heat dissipation effect without hindering the shake correction function performed by moving the movable unit  114 . 
     &lt;Positional Relationship Among Image Pickup Signal Flexible Board, Image Pickup Power Flexible Board, and Heat Dissipation Fan&gt; 
     Further, the positional relationship among the image pickup signal flexible board  111 , the image pickup power flexible board  112 , and the heat dissipation fan  130  will be described in detail with reference to  FIG.  4    and  FIGS.  5 A to  5 D . 
       FIG.  4    is a rear view of the image sensor unit  106  and the heat dissipation fan  130  when viewed obliquely from a rear of the digital camera  100 . 
     As illustrated in  FIG.  4   , the image sensor unit  106  includes the image pickup power flexible board  112  and the image pickup signal flexible board  111  that are fixed to each of the movable unit  114  and the drive mechanism  113 . 
       FIG.  5 D  is a rear view of the image sensor unit  106 , and  FIGS.  5 A,  5 B, and  5 C  illustrate an A-A section, a B-B section, and a C-C section in  FIG.  5 D , respectively. 
     As illustrated in  FIG.  5 A , the image pickup power flexible board  112  has a first end portion  112   a  that is connected to a connector mounted on the surface of the image pickup board  115   a  where the elements  115   b  are mounted. The first end portion  112   a  extends therefrom in a direction substantially parallel to the image pickup board  115   a.    
     The image pickup power flexible board  112  further has a bent portion  112   b  extending from the first end portion  112   a  and bent 180 degrees with a predetermined bending radius, and a residual portion  112   c  forming a portion between the bent portion  112   b  and a fixing portion  112   d  for fixing the image pickup power flexible board  112  to the drive mechanism  113 . 
     A second end portion  112   e  extending from the fixing portion  112   d  is connected to the main board  107 . 
     The movable unit  114  of the image sensor unit  106  is thereby driven for shake correction. 
     The bent portion  112   b  and the residual portion  112   c  absorb deformation of the image pickup power flexible board  112 , thereby reducing the influence of the tension of the image pickup power flexible board  112  on the control of the movable unit  114 . 
     As illustrated in  FIG.  5 B , the image pickup signal flexible board  111  has a bending configuration similar to the configuration of the image pickup power flexible board  112  in order to keep the influence of the tension thereof on the control of the movable unit  114  to a minimum. 
     Further, as illustrated in  FIG.  5 D , when the lateral direction and the vertical direction viewed from the rear of the digital camera  100  are defined as an X-direction and a Y-direction, respectively, the three magnets  118  included in the drive mechanism  113  are divided into an X-direction magnet  118   a  and Y-direction magnets  118   b  and  118   c  in terms of driving force generation direction. 
     The Y-direction magnet  118   b  is disposed closer to the X-direction magnet  118   a  than the Y-direction magnet  118   c.    
     A bent portion  111   b  of the image pickup signal flexible board  111  and the bent portion  112   b  of the image pickup power flexible board  112  are formed on a side away from the Y-direction magnets  118   b  and  118   c  across a connection portion with the image pickup board  115   a.    
     Further, as illustrated in  FIG.  5 C , when the heat dissipation fan  130  is observed from a plane direction perpendicular to the optical axis, the range of the blowing direction is defined as a blowing range  131   b.    
     In the blowing range  131   b , the airflow from the heat dissipation fan  130  passes through at least a part of a space between a residual portion  111   c  of the image pickup signal flexible board  111  and the image pickup board  115   a  and between the residual portion  112   c  of the image pickup power flexible board  112  and the image pickup board  115   a.    
     Further, the vent  131  of the heat dissipation fan  130  is disposed to face the image sensor unit  106 . 
     Thus, as illustrated in  FIG.  5 C , the bent portion  111   b  connecting a first end portion  111   a  and the residual portion  111   c  of the image pickup signal flexible board  111  overlaps the blowing range  131   b.    
     The bent portion  112   b  connecting the first end portion  112   a  and the residual portion  112   c  of the image pickup power flexible board  112  overlaps the blowing range  131   b.    
     The movement of the airflow generated by the heat dissipation fan  130  will now be described with reference to  FIGS.  5 C,  6 A, and  6 B .  FIG.  6 A  illustrates the image sensor unit  106  viewed from a side of the digital camera  100 .  FIG.  6 B  illustrates a D-D section in  FIG.  6 A . 
     As indicated by arrows in  FIG.  5 C , the airflow generated by the heat dissipation fan  130  is discharged from the vent  131  and subsequently passes through the space between the image pickup board  115   a  and each of the residual portion  111   c  of the image pickup signal flexible board  111  and the residual portion  112   c  of the image pickup power flexible board  112 . 
     At this time, the air on the image pickup board  115   a  to which heat is transferred from the image pickup board  115   a  is moved along the arrows in  FIG.  5 C  by the airflow from the heat dissipation fan  130 , and diffused inside the digital camera  100 . 
     When the image sensor unit  106  is observed from the rear of the digital camera  100  at this time, the air flows as indicated by arrows in  FIG.  6 B . 
     The bent portions  111   b  and  112   b  each overlap the blowing range  131   b  as described above, but the heat dissipation fan  130  is disposed so that the bent portions  111   b  and  112   b  are outside the blowing range  131   a.    
     It is thus possible to implement the bending configuration without obstructing the airflow due to the bent portions  111   b  and  112   b.    
     As a result, the airflow generated by the heat dissipation fan  130  can spread out over a wide area on the image pickup board  115   a , so that a temperature rise of the image sensor  115  can be effectively suppressed. 
     In addition, the position of each of the bent portions  111   b  and  112   b  slightly changes in the Y-direction when the movable unit  114  is driven. 
     Thus, it is desirable to dispose the bent portions  111   b  and  112   b  at positions a certain distance from the Y-direction magnets  118   b  and  118   c  in the Y-direction in order to prevent the bent portions  111   b  and  112   b  from coming into contact with the Y-direction magnets  118   b  and  118   c  and affecting the attitude control of the movable unit  114 . 
     In the present exemplary embodiment, the bent portions  111   b  and  112   b  are formed at positions facing the Y-direction magnets  118   c  and  118   b , respectively, across the connection portion with the image pickup board  115   a.    
     Further, as illustrated in  FIG.  6 B , a vent center  131   c  of the heat dissipation fan  130  is disposed between the bent portions  111   b  and  112   b  and the Y-direction magnets  118   b  and  118   c.    
     Such a configuration makes it possible to include the distance for preventing the bent portions  111   b  and  112   b  from coming into contact with the Y-direction magnets  118   b  and  118   c , in the blowing range  131   a.    
     Therefore, even if the heat dissipation fan  130  is disposed so that the bent portions  111   b  and  112   b  are outside the blowing range  131   a , a large area where the blowing range  131   a  and the image pickup board  115   a  overlap each other can be secured when viewed from the optical axis direction, and the heat dissipation efficiency is high. 
     Moreover, such a configuration prevents the bent portions  111   b  and  112   b  from receiving a force from the airflow generated by the heat dissipation fan  130 , so that the influence on the controllability of the movable unit  114  can be reduced. 
     Features of the present exemplary embodiment are as follows. 
     One of the features is that the closest bent portion  112   b  (a bent portion closest to a side of the image pickup power flexible board  112  connected to the image pickup board  115   a ) is not within the range of the blowing direction. 
     An image pickup apparatus (the digital camera  100 ) according to the present exemplary embodiment includes an image sensor (the image sensor  115 ) configured to move within a movable range of the image sensor in a direction different from an optical axis direction, a first circuit board (the image pickup board  115   a ) on which the image sensor is mounted, and a second circuit board (the main board  107 ) facing the first circuit board. 
     The image pickup apparatus further includes a first flexible board (the image pickup power flexible board  112 ) configured to electrically connect the first circuit board and the second circuit board, and a fan (the heat dissipation fan  130 ). 
     The first flexible board is bent in an area overlapping the movable range of the image sensor in the optical axis direction. 
     As viewed from the optical axis direction, an inner circumferential surface (an inner surface) of a bent portion (the bent portion  112   b ) of the first flexible board, which is closest to a side of the first flexible board connected to the first circuit board, is disposed to be outside a range (the blowing range  131   a ) of a blowing direction of an airflow discharged from a vent of the fan. 
     Another feature of the present exemplary embodiment is that the closest bent portion  112   b , the connection portion, and the y-direction magnet  118   b  are disposed in order from a top side of the image pickup apparatus. 
     The image pickup apparatus further includes a magnet (the magnets  118 ) configured to move the image sensor within the movable range. 
     The bent portion closest to the side connected to the first circuit board is disposed at a position facing the magnet across a connection portion connecting the first circuit board and the first flexible board. 
     Yet another feature of the present exemplary embodiment is a position of a center of the vent of the fan. 
     As viewed from the optical axis direction, a center of the vent of the fan is located between the bent portion closest to the side connected to the first circuit board and the magnet. 
     Yet another feature of the present exemplary embodiment is a position of the first flexible board in the optical axis direction. 
     A position of the first flexible board in the optical axis direction is located within the range (the blowing range  131   b ) of the blowing direction of the airflow discharged from the vent of the fan. 
     &lt;Rear View of Image Sensor Unit&gt; 
     A second exemplary embodiment of the present disclosure will be described with reference to  FIGS.  7 A to  7 C  and  FIGS.  8 A and  8 B . For simplicity of the description, a description of similarities between the first and second exemplary embodiments will be omitted, and differences from the first exemplary embodiment will be described. 
       FIG.  7 C  is a rear view of the image sensor unit  106 , and  FIGS.  7 A and  7 B  illustrate an A-A section and a B-B section in  FIG.  7 C , respectively. 
       FIG.  8 A  illustrates the image sensor unit  106  viewed from a side of the digital camera  100 , and  FIG.  8 B  illustrates a C-C section in  FIG.  8 A . 
     Unlike the first exemplary embodiment, an image pickup power flexible board  212  ( 212   a  to  212   e ) is disposed in an orientation reversed 180 degrees from that of the image pickup signal flexible board  111 , as illustrated in  FIGS.  7 A and  7 B . 
     This configuration makes it possible to cancel out the influences of the respective tensions of the image pickup power flexible board  212  and the image pickup signal flexible board  111  on the movable unit  114 , and is suitable for the controllability of the movable unit  114 . 
     However, as illustrated in  FIG.  8 B , a bent portion  212   b  of the image pickup power flexible board  212  is disposed at a position a certain distance from the Y-direction magnet  118   b.    
     Thus, the bent portion  212   b  is within the blowing range  131   a  of the heat dissipation fan  130 , and can easily receive a force from the airflow. 
     However, as illustrated in  FIG.  8 B , the thickness direction of the bent portion  212   b  of the image pickup power flexible board  212  is orthogonal to the blowing direction, and the bent portion  212   b  is disposed so as not to easily receive the force from the airflow. 
     In addition, as illustrated in  FIG.  8 B , the image pickup power flexible board  212  is bent in the Y-direction when viewed from the optical axis direction, and thus can be said to be orthogonal to the blowing direction. 
     Besides being advantageous to the controllability of the movable unit  114  in a case where the heat dissipation fan  130  is not driven, such a configuration can reduce the influence of the force received by the image pickup power flexible board  212  from the airflow in a case where the heat dissipation fan  130  is driven. 
     At the same time, the airflow generated by the heat dissipation fan  130  can spread out over a wide area on the image pickup board  115   a  because the airflow is not easily obstructed by the bent portion  212   b , so that a temperature rise of the image sensor  115  can be effectively suppressed. 
     Features of the present exemplary embodiment are as follows. One of the features is that the blowing direction of the vent  131  and the thickness direction of the bent portion  212   b  are orthogonal to each other. 
     An image pickup apparatus (the digital camera  100 ) according to the present exemplary embodiment includes an image sensor (the image sensor  115 ) configured to move within a movable range of the image sensor in a direction different from an optical axis direction, a first circuit board (the image pickup board  115   a ) on which the image sensor is mounted, and a second circuit board (the main board  107 ) facing the first circuit board. 
     The image pickup apparatus further includes a first flexible board (the image pickup power flexible board  212 ) configured to electrically connect the first circuit board and the second circuit board, and a fan (the heat dissipation fan  130 ). 
     The first flexible board is bent in an area overlapping the movable range of the image sensor in the optical axis direction. 
     A position of the first flexible board in the optical axis direction is located within a range (the blowing range  131   b ) of a blowing direction of an airflow discharged from a vent of the fan. 
     A thickness direction of a bent portion (the bent portion  212   b ) of the first flexible board, which is closest to a side of the first flexible board connected to the first circuit board, is orthogonal to the blowing direction of the airflow discharged from the vent of the fan. 
     Another feature of the present exemplary embodiment is that the bending direction and the blowing direction are orthogonal to each other. 
     An image pickup apparatus according (the digital camera  100 ) to the present exemplary embodiment includes an image sensor (the image sensor  115 ) configured to move within a movable range of the image sensor in a direction different from an optical axis direction, a first circuit board (the image pickup board  115   a ) on which the image sensor is mounted, and a second circuit board (the main board  107 ) facing the first circuit board. 
     The image pickup apparatus further includes a first flexible board (the image pickup power flexible board  212 ) configured to electrically connect the first circuit board and the second circuit board, and a fan (the heat dissipation fan  130 ). 
     The first flexible board is bent in an area overlapping the movable range of the image sensor in the optical axis direction. 
     A position of the first flexible board in the optical axis direction is located within a range (the blowing range  131   b ) of a blowing direction of an airflow discharged from a vent of the fan. 
     A bending direction of a bent portion (the bent portion  212   b ) of the first flexible board, which is closest to a side of the first flexible board connected to the first circuit board, is orthogonal to the blowing direction of the airflow discharged from the vent of the fan. 
     Another feature of the present exemplary embodiment relates to a longitudinal direction and a short direction of the image sensor. 
     The blowing direction is a longitudinal direction of the image sensor, and the bending direction is a short direction of the image sensor. 
     A third exemplary embodiment of the present disclosure will be described with reference to  FIGS.  9 A and  9 B  and  FIGS.  10 A to  10 D . For simplicity of the description, a description of similarities between the first and third exemplary embodiments will be omitted, and differences from the first exemplary embodiment will be described. 
       FIG.  9 A  is a rear view of the image sensor unit  106  and the heat dissipation fan  130  as viewed obliquely from the rear of the digital camera  100 .  FIG.  9 B  is a view in which the image pickup signal flexible board  111  and the image pickup power flexible board  112  are hidden in  FIG.  9 A  to make it easy to view illustrated components. 
     In the present exemplary embodiment, the first flexible board is applied to a graphite sheet in addition to the flexible board. 
     As illustrated in  FIGS.  9 A and  9 B , the image sensor unit  106  includes graphite sheets  121  and  122  each fixed to the drive mechanism  113  and the movable unit  114  to overlap the image pickup signal flexible board  111  and the image pickup power flexible board  112 , respectively. 
     The graphite sheets  121  and  122  each function as a heat dissipation member having flexibility and less likely to affect the controllability of the movable unit  114 , while transferring heat generated in the movable unit  114  to the drive mechanism  113 . 
       FIG.  10 D  is a rear view of the image sensor unit  106 , and  FIGS.  10 A,  10 B, and  10 C  illustrate an A-A section, a B-B section, and a C-C section in  FIG.  10 D , respectively. 
     As illustrated in  FIGS.  10 A , the graphite sheet  122  has a first end portion  122   a  attached in contact with the elements  115   b  on the image pickup board  115   a , and extending therefrom in a direction substantially parallel to the image pickup board  115   a.    
     The graphite sheet  122  further has a bent portion  122   b  extending from the first end portion  122   a  and bent 180 degrees with a predetermined bending radius, and a residual portion  122   c  forming a portion between the bent portion  122   b  and a fixing portion  122   d  for fixing the graphite sheet  122  to the drive mechanism  113 . 
     Such a configuration reduces the influence of the tension of the graphite sheet  122  on the control of the movable unit  114  by absorbing deformation of the graphite sheet  122  using the bent portion  122   b  and the residual portion  122   c , even if the movable unit  114  of the image sensor unit  106  is driven for shake correction. 
     As illustrated in  FIG.  10 A , the image pickup power flexible board  112  is disposed so that an inner circumferential surface (an inner surface) of the bent portion  112   b  of the image pickup power flexible board  112  faces an outer surface of the bent portion  122   b  of the graphite sheet  122 . 
     The graphite sheet  121  has a bending configuration similar to the configuration of the graphite sheet  122  in order to keep the influence of the tension thereof on the control of the movable unit  114  to a minimum. 
     As illustrated in  FIG.  10 B , the image pickup signal flexible board  111  is disposed so that an inner circumferential surface (an inner surface) of the bent portion  111   b  of the image pickup signal flexible board  111  faces an outer surface of a bent portion  121   b  of the graphite sheet  121 . 
     Such an arrangement can bring a fixing portion  121   d  of the graphite sheet  121  and the fixing portion  122   d  of the graphite sheet  122  into direct and fixed contact with the drive mechanism  113  without interposing the image pickup signal flexible board  111  and the image pickup power flexible board  112  therebetween. 
     Thus, this is suitable for heat dissipation from the movable unit  114  to the drive mechanism  113 . 
     The configuration of the bent portions  121   b  and  122   b  of the graphite sheets  121  and  122  can be replaced with the bent portions  111   b  and  112   b  of the image pickup signal flexible board  111  and the image pickup power flexible board  112  in the first exemplary embodiment. 
     Thus, it is apparent that an effect similar to the effect of the first exemplary embodiment can be obtained. 
     Further, in the first, second, and third exemplary embodiments, the heat dissipation fan  130  itself is not physically connected to the movable unit  114 , and thus the heat dissipation effect can be produced without hindering the shake correction function performed by moving the movable unit  114 . 
     Furthermore, in the first, second, and third exemplary embodiments, the blowing direction coincides with the longitudinal direction of the image sensor  115 . 
     The bending direction of each of the image pickup signal flexible board  111 , the image pickup power flexible board  112 , and the graphite sheets  121  and  122  coincides with the short direction of the image sensor  115 . 
     Such a configuration can efficiently spread out the air on the image pickup board  115   a , inside the digital camera  100  without increasing the width of the blowing direction of the heat dissipation fan  130  to match the width of the image sensor  115  in the longitudinal direction. 
     In the first, second, and third exemplary embodiments, for example, the heat dissipation fan  130  is in a state of being operated with an air volume of 4.5 L/min. Liter per minute (L/min) is the unit of volume flow. 
     Incorporation of the heat dissipation fan  130  into the digital camera  100  can reduce the maximum temperature of the image sensor unit  106  by 10° C. This suppresses the temperature rise of the heat source, making it difficult to reach a temperature limit at which the digital camera  100  stops functioning because of heat generation. 
     &lt;Block Diagram Illustrating Configuration Example of Digital Camera&gt; 
       FIG.  11    is a block diagram illustrating an example of a configuration of a digital camera  400  according to an exemplary embodiment of the present disclosure. 
     A shutter  410  is a focal plane shutter that can freely control the exposure period of an image pickup unit  411  (described below). A system control unit  420  (described below) performs this control. 
     The image pickup unit  411  is an image pickup device that has an image pickup plane for forming a subject image (an optical image) that has passed through a lens  501 , and outputs an electrical signal (an analog signal) based on the optical image on the image pickup plane by performing photoelectric conversion. 
     For the image pickup unit  411 , a charge-coupled device (CCD) sensor or a complementary metal-oxide semiconductor (CMOS) sensor is used. 
     An analog-to-digital (A/D) converter  412  is a signal conversion unit used to convert the analog signal output from the image pickup unit  411  into a digital signal. 
     An image processing unit  413  is an image calculation unit that generates image data by performing predetermined pixel interpolation, resizing processing such as reduction, and color conversion processing on the digital signal from the A/D converter  412  or a digital signal from a memory control unit  422  (described below). 
     The system control unit  420  controls an aperture position and a lens position based on a calculation result obtained by the image processing unit  413 . 
     The image processing unit  413  further performs calculation processing using the image data, and performs through-the-lens (TTL) automatic white balance (AWB) processing based on the obtained calculation result. 
     The system control unit  420  includes at least one processor or circuit, and controls the entire digital camera  400 . 
     Each process according to the present exemplary embodiment is implemented by executing a program stored in a nonvolatile memory  423  (described below). 
     A memory  421  is a storage unit that temporarily stores the digital signal into which the A/D converter  412  converts the analog signal obtained by the image pickup unit  411 , and the image data generated by the image processing unit  413 . 
     The memory  421  has a sufficient capacity to store a predetermined number of still images, and a moving image and sound for a predetermined length of time. 
     The memory control unit  422  controls transmission and reception of the data controlled by the system control unit  420  to and from the A/D converter  412 , the image processing unit  413 , and the memory  421 . 
     The digital signal output from the A/D converter  412  is stored into the memory  421  via the image processing unit  413  and the memory control unit  422 , or directly via the memory control unit  422 . 
     The nonvolatile memory  423  is an electrically erasable and recordable read only storage unit, and stores constants, programs, and the like for the operation of the system control unit  420 . 
     A system memory  424  is a readable and writable storage unit that stores constants, variables, programs read out from the nonvolatile memory  423 , and the like for the operation of the system control unit  420 . 
     A system timer  425  is a clocking unit that measures a time period before execution of automatic power-off for turning off various display members (described below), and an exposure period. 
     The automatic power-off has a function of turning off the various display members (described below) to prevent battery drain in a case where it is determined that a user is not operating the digital camera  400 . 
     A power supply unit  430  includes a primary battery such as an alkaline cell or a lithium battery, a secondary battery such as a nickel-cadmium (NiCd) battery, a nickel-metal hydride (NiMH) battery, or a lithium (Li) battery, an alternating current (AC) adapter, or the like. 
     A power supply control unit  431  includes a circuit for detecting the power supply unit  430  serving as a power source for driving the digital camera  400 , a direct current (DC)-DC converter, and a switch circuit for switching between power supply destinations. 
     The power supply unit  430  further detects whether the battery is attached, the type of the battery, and a remaining battery level. 
     In addition, the power supply control unit  431  controls the DC-DC converter based on the detection result and an instruction of the system control unit  420 , and supplies an appropriate voltage to a supply destination at an appropriate timing. 
     A communication terminal  440  is provided in the digital camera  400 , and is electrically connected to a lens communication terminal  506  (described below). 
     The electrical connection of the communication terminal  440  to the lens communication terminal  506  enables the system control unit  420 , which controls the entire digital camera  400 , to communicate with a lens unit  500  (described below). 
     A storage medium interface (I/F)  441  is an interface with a storage medium  600  (described below). 
     An attitude detection unit  442  detects an attitude of the digital camera  400  with respect to a gravity direction. 
     Based on the attitude detected by the attitude detection unit  442 , it is possible to output orientation information about whether an image obtained by the image pickup unit  411  is an image captured by holding the digital camera  400  laterally or an image captured by holding the digital camera  400  vertically. 
     The system control unit  420  can add the orientation information output by the attitude detection unit  442  to the image data. 
     For the attitude detection unit  442 , an acceleration sensor, a gyroscope sensor, or the like can be used. 
     When the acceleration sensor or the gyroscope sensor is used for the attitude detection unit  442 , a movement (such as a panning, tilting, lifted, or stationary state) of the digital camera  400  can also be detected. 
     An eyepiece portion  443  is a portion in the digital camera  400  that a user&#39;s eye (an object)  700  approaches (comes in contact with). 
     An eye-contact detection unit  444  is an eye-contact detection sensor that detects approach (eye contact) or leaving (eye separation) of the eye  700  with respect to the eyepiece portion  443 . 
     The eye-contact detection unit  444  detects the contact of the eye  700  with the eyepiece portion  443 , based on whether light is received by a light-receiving unit (not illustrated) of an infrared proximity sensor. 
     After the contact of the eye  700  is detected, the system control unit  420  determines that an eye contact state continues until the separation of the eye  700  is detected. 
     After the separation of the eye  700  is detected, the system control unit  420  determines that a non-eye contact state continues until the contact of the eye  700  is detected. 
     The infrared proximity sensor is merely an example, and any other type of sensor that can detect the approach of an eye or an object as the eye contact state may be adopted for the eye-contact detection unit  444 . 
     The memory  421  described above also serves as a memory (a video memory) for image display. 
     The digital signal and the image data written in the memory  421  are displayed on a rear display unit  450  or an electronic view finder (EVF)  451  via the memory control unit  422 . 
     The rear display unit  450  performs display based on the signal from the memory control unit  422 . 
     In a case where eye contact is detected by the eye-contact detection unit  444 , the EVF  451  performs display based on the signal from the memory control unit  422 . 
     The digital signals into which the analog signals generated by the image pickup unit  411  are converted by the A/D converter  412  are recorded in the memory  421 , and sequentially transferred to the rear display unit  450  or the EVF  451  for display. 
     Live view imaging display, which is real time display, can be thereby performed. 
     The system control unit  420  switches between display (a display state) and non-display (a non-display state) of each of the rear display unit  450  and the EVF  451 , depending on the state detected by the eye-contact detection unit  444  described above. 
     During the non-eye contact state, the rear display unit  450  is in the display state, and the EVF  451  is in the non-display state. 
     During the eye contact state, the EVF  451  is in the display state, and the rear display unit  450  is in the non-display state. 
     An operation unit  460  includes various operation members and serves as an input unit for accepting operations from the user. 
     The operation unit  460  includes the various operation members (a mode change switch  461 , a shutter button  462 , a first shutter switch  463 , a second shutter switch  464 , a touch panel  465 , and a power switch  466 ) to be described below. 
     Further, the operation unit  460  is used to input various operation instructions to the system control unit  420 . 
     The mode change switch  461  is used to change the operating mode of the system control unit  420  to a mode such as a still image capturing mode or a moving image capturing mode. 
     The still image capturing mode includes an automatic image capturing mode, an automatic scene determination mode, and a manual image capturing mode, as image capturing modes. 
     The still image capturing mode further includes an aperture priority (Av) mode (Av mode), a shutter speed priority mode (Time-value (Tv) mode or Tv mode), and a program automatic exposure (AE) mode (P mode), as image capturing modes. 
     The moving image capturing mode may similarly include a plurality of image capturing modes. 
     The shutter button  462  is used by the user to give an image capturing preparation instruction and an image capturing instruction. 
     The first shutter switch  463  is turned on in the middle of operating the shutter button  462  of the digital camera  400 , i.e., when the shutter button  462  is pressed halfway (when the image capturing preparation instruction is issued), thereby generating a first shutter switch signal SW 1 . 
     The first shutter switch signal SW 1  starts an image capturing preparation operation including automatic focus (AF) processing, AE processing, and AWB processing. 
     The second shutter switch  464  is turned on when the shutter button  462  is operated completely, i.e., when the shutter button  462  is fully pressed (when the image capturing instruction is issued), thereby generating a second shutter switch signal SW 2 . 
     The system control unit  420  performs processing from reading out the analog signal from the image pickup unit  411  to converting the signal using the A/D converter  412  and the image processing unit  413 , based on the second shutter switch signal SW 2 . 
     In addition, the system control unit  420  starts an image capturing processing operation up to writing the image data temporarily recorded in the memory  421  into the storage medium  600  (described below). 
     The touch panel  465  is a device for detecting a touch operation or a drag operation performed by the user. 
     In the present exemplary embodiment, the touch panel  465  is integral with the rear display unit  450 , and can be operated by the user touching a display portion of the rear display unit  450  with a finger. 
     The power switch  466  is used to power on or off the digital camera  400 . The power supply control unit  431  controls power supply from the power supply unit  430  based on the switching operation on the power switch  466 . 
     A heat dissipation fan  470  is controlled by the system control unit  420  to cool a heat source in the digital camera  400 . 
     The lens unit  500  is an interchangeable lens that is detachably attached to the digital camera  400 . 
     The lens  501  is a lens group for generating an optical image (a subject image) from subject light reflected by a subject, and includes a plurality of lenses, but one lens is illustrated in  FIG.  11    for simplicity. 
     The lens communication terminal  506  is a communication terminal for the lens unit  500  to communicate with the digital camera  400 . 
     The lens unit  500  is communicable with the system control unit  420  that controls the entire digital camera  400 , in a state where the lens communication terminal  506  and the communication terminal  440  are electrically connected to each other as described above. 
     This enables the system control unit  420  to communicate with a lens drive circuit  502  and an aperture drive circuit  504  via a lens system control circuit  505  to control the position of an aperture  503  and the in-focus state of a real image formed by displacing the lens  501 . 
     The storage medium  600 , such as a memory card, is detachably attached to the digital camera  400  and provided to record captured images. 
     Examples of the storage medium  600  include a secure digital (SD) card, a memory that retains data in the absence of a power supply such as a FLASH® memory, and a hard disk. 
     INDUSTRIAL APPLICABILITY 
     The technique according to the exemplary embodiments of the present disclosure is applicable to electronic apparatuses and image capturing systems. 
     According to an exemplary embodiment of the present disclosure, it is possible to prevent the heat dissipation performance of an image sensor from being reduced due to a flexible board obstructing an airflow generated by an airflow generation unit. 
     While the present disclosure has been described with reference to exemplary embodiments, it is to be understood that the disclosure is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions. 
     This application claims the benefit of Japanese Patent Application No. 2021-191536, filed Nov. 25, 2021, which is hereby incorporated by reference herein in its entirety.