Patent Publication Number: US-2022217258-A1

Title: Imaging apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a Continuation of U.S. application Ser. No. 16/166,623, filed Oct. 22, 2018, which claims the benefit of Japanese Patent Applications No. 2017-206019, filed Oct. 25, 2017, and No. 2018-148511, filed Aug. 7, 2018, which are hereby incorporated by reference herein in their entireties. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to an imaging apparatus. 
     Description of the Related Art 
     In a network camera represented by, for example, a monitoring camera, a camera unit images incident light passed through a lens unit by an image capturing element, to acquire an image. 
     When an object in depth of field is imaged, an image in an excellent imaging state is typically acquired, and when an object outside the depth of field is imaged, an image deteriorated in the imaging state is typically acquired. 
     In particular, when a network camera is used with a diaphragm in an open state, an imaging range within a range of an imaging screen easily falls outside the depth of field. Accordingly, in terms of monitoring use, when an object such as a human face is within a range where an imaging state is poor, the object may not be recognized. In such a case, the depth of field can be made deeper by narrowing down the diaphragm. In the monitoring during the hours of darkness, however, there is a case where a network camera is used with the diaphragm in the open state in order to take in a large quantity of light. In such a case, it is not possible to narrow down the diaphragm. Although a plurality of monitoring cameras may be installed according to each distance to the object, to capture the object within the depth of field, this increases the number of cameras. Accordingly, a camera by itself achieving deep depth of field is demanded. 
     In response to the demand, there is a camera technology including a tilt function that tilts an image capturing element relative to a lens unit, to widen the range of the depth of field, as a technology to make the depth of field deep while the diaphragm is open. 
     When the image capturing element is tilted relative to the lens unit, however, a gap occurs around a tilting unit. 
     The gap is desirably sealed in order to prevent foreign matters entering the camera unit from the gap, from being appeared in a captured image. 
     Some of the existing imaging apparatuses without the tilt function include a sealing member that is disposed between the image capturing element and an optical filter in order to prevent foreign matters from entering the camera unit. 
     For example, Japanese Patent Application Laid-Open No. 2016-139763 discusses a structure in which a seal glass and a frame to which an image capturing element is attached are bonded to each other by a sealing resin. 
     In the case of an imaging apparatus in which the camera technology including the tilt function for tilting the image capturing element relative to the lens unit is implemented, however, a size of the gap around the tilting unit varies by tilting of the image capturing element relative to the lens unit. Accordingly, if the sealing structure discussed in Japanese Patent Application Laid-Open No. 2016-139763 is applied to the imaging apparatus including the tilt function, the gap may not be sealed when a tilting angle is increased. 
     SUMMARY OF THE INVENTION 
     According to an aspect of the present invention, an imaging apparatus includes an image capturing element configured to convert an image obtained through an imaging lens, into an electronic signal, an image capturing element holder configured to hold the image capturing element, a base member configured to tiltably support the image capturing element holder, a driving member configured to tilt the image capturing element holder to incline the image capturing element relative to a surface orthogonal to an optical axis of the imaging lens, and a sealing member configured to seal a gap between the base member and the image capturing element holder, wherein the sealing member deforms by the tilting of the image capturing element holder. 
     Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded perspective view illustrating a network monitoring camera according to a first exemplary embodiment. 
         FIG. 2  is a perspective view illustrating an image capturing element unit attached to a lens barrel according to the first exemplary embodiment. 
         FIG. 3  is an exploded perspective view illustrating the lens barrel and the image capturing element unit according to the first exemplary embodiment. 
         FIG. 4A  is a perspective view illustrating the image capturing element unit according to the first exemplary embodiment,  FIG. 4B  is a cross-sectional view illustrating the image capturing element unit according to the first exemplary embodiment, and  FIG. 4C  is a cross-sectional view illustrating the image capturing element unit when an image capturing element is tilted, according to the first exemplary embodiment. 
         FIG. 5  is a cross-sectional view illustrating an image capturing element unit according to a second exemplary embodiment. 
         FIG. 6  is an exploded perspective view illustrating a network monitoring camera according to a third exemplary embodiment. 
         FIG. 7  is an exploded perspective view illustrating an imaging apparatus according to the third exemplary embodiment. 
         FIG. 8  is a perspective view illustrating the imaging apparatus according to the third exemplary embodiment. 
         FIG. 9A  is a cross-sectional view illustrating the imaging apparatus according to the third exemplary embodiment, and  FIG. 9B  is a cross-sectional view illustrating the imaging apparatus when an image capturing element is tilted, according to the third exemplary embodiment. 
         FIG. 10A  is a cross-sectional view illustrating an imaging apparatus according to a fourth exemplary embodiment, and  FIG. 10B  is a cross-sectional view illustrating the imaging apparatus when an image capturing element is tilted, according to the fourth exemplary embodiment. 
         FIG. 11  is a perspective view illustrating a state where a cover is removed from the imaging apparatus according to the fourth exemplary embodiment. 
         FIG. 12  is a perspective view illustrating a state where a cover is removed from an imaging apparatus according to a fifth exemplary embodiment. 
         FIG. 13A  is a cross-sectional view illustrating an imaging apparatus according to a sixth exemplary embodiment, and  FIG. 13B  is a cross-sectional view illustrating the imaging apparatus when an image capturing element is tilted, according to the sixth exemplary embodiment. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     Some exemplary embodiments of the present invention are described below with reference to drawings. 
       FIG. 1  is a configuration diagram illustrating a network monitoring camera (hereinafter, referred to as monitoring camera) as an example of an imaging apparatus.  FIG. 2  is a perspective view illustrating an image capturing element unit attached to a lens barrel according to a first exemplary embodiment.  FIG. 3  is an exploded perspective view illustrating the lens barrel and the image capturing element unit according to the first exemplary embodiment. 
     The network monitoring camera includes a cover  2 , a dome cover  3 , a lens barrel  4 , an image capturing element unit  5 , and a pan-tilt rotation unit  6 . 
     The cover  2  has, at a center, an opening in which the dome cover  3  is disposed, and forms a housing together with the pan-tilt rotation unit  6 . 
     The dome cover  3  has a hemispherical shape and covers the lens barrel  4 . The dome cover  3  is held and fixed between the cover  2  and the pan-tilt rotation unit  6 . 
     The pan-tilt rotation unit  6  rotatably supports the lens barrel  4  to which the image capturing element unit  5  is attached, in pan, tilt, and rotation directions. The pan-tilt rotation unit  6  is fastened to the cover  2  by fastening screws  1 . 
     The lens barrel  4  includes lenses of a fixed group and a moving group as imaging lenses, a front fixing frame  7 , and guide bars  15 ,  16 ,  19 , and  20 . The lens barrel  4  further includes a lens moving frame  10 , a diaphragm unit  12 , a lens fixing frame  13 , a lens moving frame  17 , a rear fixing frame  23 , etc. 
     The lenses of the fixed group and the moving group include a fixed lens  8  fixed in an optical axis direction, a zoom lens  9  that moves in the optical axis direction to perform variable power operation, and a fixed lens  14  fixed in the optical axis direction. The lenses of the fixed group and the lenses of moving group further include a focus lens  18  that moves in the optical axis direction to perform focusing operation, and a fixed lens  25  that is fixed in the optical axis direction. The front fixing frame  7  holds the fixed lens  8 . The lens moving frame  10  holds the zoom lens  9 . The lens moving frame  10  is held by the guide bar  15  so as to be movable in the optical axis direction. Rotational movement of the lens moving frame  10  around the guide bar  15  is regulated by engagement of the guide bar  16  and a U-shaped groove on the lens moving frame  10 . 
     A rack  11  is fixed to the lens moving frame  10  while being biased in the optical axis direction and a rotation direction by a rack spring (not illustrated), engages with a screw part of a stepping motor  22 , and moves together with the lens moving frame  10  in the optical axis direction by rotation of the screw part. 
     The diaphragm unit  12  adjusts a quantity of light entering the lens barrel  4 . The diaphragm unit  12  is fixed to the lens fixing frame  13  by screws (not illustrated). 
     The lens fixing frame  13  holds the fixed lens  14 . The lens moving frame  17  holds the focus lens  18 . The lens moving frame  17  is supported by the guide bar  20  so as to be movable in the optical axis direction. Rotation of the lens moving frame  17  around the guide bar  20  is regulated by engagement of the guide bar  19  and a U-shaped groove on the lens moving frame  17 . A rack (not illustrated) coupled to the lens moving frame  17  is fixed to the lens moving frame  17  while being biased in the optical axis direction and the rotation direction by a rack spring (not illustrated), engages with a screw part of a stepping motor  24 , and moves together with the lens moving frame  17  in the optical axis direction by rotation of the screw part. 
     The rear fixing frame  23  holds the fixed lens  25 . The front fixing frame  7  and the lens fixing frame  13  are fixed to the rear fixing frame  23  by screws (not illustrated). The guide bars  15  and  20  are fixed to be held between the front fixing frame  7  and the rear fixing frame  23 . The guide bar  16  is fixed to be held between the front fixing frame  7  and the lens fixing frame  13 . The guide bar  19  is fixed to be held between the lens fixing frame  13  and the rear fixing frame  23 . Photo interrupters  21  and  26  are fixed to a flexible printed circuit (FPC, not illustrated) by soldering. The FPC is connected to the diaphragm unit  12 , stepping motors  22 ,  24 ,  101 , and  102 , and the photo interrupters  21  and  26 , and starts up them through energization. 
     The photo interrupter  21  is disposed in a moving region of the lens moving frame  10 , and controls a position of the lens moving frame  10  based on an output of the photo interrupter  21  and the number of driving pulses of the stepping motor  22 . The photo interrupter  26  is disposed in a moving region of the lens moving frame  17 , and controls a position of the lens moving frame  17  based on an output of the photo interrupter  26  and the number of driving pulses of the stepping motor  24 . 
     Next, an optical filter driving mechanism  100  is described. The optical filter driving mechanism  100  inserts an infrared cut-off filter  107  or a dummy glass  108  into an optical path, or retreats the infrared cut-off filter  107  or the dummy glass  108  from the optical path. The optical filter driving mechanism  100  inserts the infrared cut-off filter  107  into the optical path in a day mode, and retreats the infrared cut-off filter  107  from the optical path and inserts the dummy glass  108  into the optical path in a night mode. 
     A filter holding frame  109  holds the dummy glass  108 , and is supported by guide bars  105  and  106  fixed to the rear fixing frame  23  so as to be movable in a direction substantially perpendicular to the optical axis. A gear unit  103  engaged with the stepping motor  101  fixed to the rear fixing frame  23  by screws  111  engages with a gear part provided on the filter holding frame  109 , and the filter holding frame  109  is driven in the direction substantially perpendicular to the optical axis. 
     A filter holding frame  110  holds the infrared cut-off filter  107 , and is supported by the guide bars  105  and  106  so as to be movable in the direction substantially perpendicular to the optical axis. A gear unit  104  engaged with the stepping motor  102  fixed to the rear fixing frame  23  by screws  112  engages with a gear part provided on the filter holding frame  110 , and the filter holding frame  110  is driven in the direction substantially perpendicular to the optical axis. 
     Next, the image capturing element unit  5  is described with reference to  FIG. 2  to  FIG. 4C .  FIG. 4A  is a perspective view illustrating the image capturing element unit  5  according to the first exemplary embodiment.  FIG. 4B  is a cross-sectional view illustrating the image capturing element unit  5  according to the first exemplary embodiment.  FIG. 4C  is a cross-sectional view illustrating the image capturing element unit  5  when an image capturing element is tilted, according to the first exemplary embodiment. 
     The image capturing element unit  5  includes a tilt base  501 , a sealing member  502 , an image capturing element holder  503 , and an image capturing element sealing member  511 . 
     The tilt base  501  serving as a base member is fixed to the rear fixing frame  23  by screws (not illustrated). An image capturing element  516  converts an image obtained through the imaging lens into an electronic signal. The image capturing element  516  is soldered to a circuit board  518  that electrically connects the image capturing element  516 , and is bonded to an image capturing element sheet metal  512  by an adhesive (not illustrated). The FPC  517  connects the circuit board  518  to the zoom lens  9 , the focus lens  18 , the diaphragm unit  12 , and a driving circuit board (not illustrated) of the optical filter driving mechanism  100 . 
     The image capturing element holder  503  is tiltable to a surface orthogonal to the optical axis. Bearings  504  and  507  are disposed on a tilt shaft of the image capturing element holder  503 . Further, a wave washer  505  and a bearing washer  506  are disposed between the image capturing element holder  503  and the bearing  507 , and the image capturing element holder  503  is biased in the tilt shaft direction by the wave washer  505  and the bearing washer  506 . Further, the image capturing element holder  503  supports the image capturing element sheet metal  512 . An optical low-pass filter  510  and the image capturing element sealing member  511  described below are inserted in order into the image capturing element holder  503 . 
     The image capturing element sealing member  511  serving as a second sealing member seals a gap between the image capturing element holder  503  and the image capturing element  516 . The image capturing element sealing member  511  is held between the image capturing element sheet metal  512  and the image capturing element holder  503  by fixing the image capturing element sheet metal  512  attached with the image capturing element  516  and the circuit board  518 , to the image capturing element holder  503  by fastening screws  519 . 
     The sealing member  502  seals a gap between the image capturing element holder  503  and the tilt base  501 . The sealing member  502  is fixed to the tilt base  501  by bonding, and is pressurized toward the tilt base  501  by the image capturing element holder  503 . The sealing member  502  is formed of an elastic light-shielding material such as rubber, and deforms by tilting of the image capturing element holder  503 . 
     A stepping motor  514  serving as a driving member is fixed to the tilt base  501 , and a worm  513  is fixed to a motor shaft by indentation, etc. A worm wheel is integrally provided on the image capturing element holder  503 , and engages with the worm  513 . The stepping motor  514  is connected to an FPC (not illustrated), and drives and rotates the worm  513  by energization, to tilt the image capturing element holder  503  and the image capturing element  516 . A tension spring  515  is to remove backlash between the worm  513  and the worm wheel, and is attached to the tilt base  501  and the image capturing element holder  503  to generate biasing force in a tension direction. 
     An initial tilting reference position of the image capturing element holder  503  is determined in such a manner that a voltage output value of a photo interrupter fixed to the tilt base  501  is detected by a detection member integrally provided on the image capturing element holder  503 , and the number of driving pulses of the stepping motor  514  is calculated. 
     Next, relationship between tilting of the image capturing element holder  503  and the sealing member  502  is described. As illustrated in  FIG. 4B , when the stepping motor  514  is driven in a state where the image capturing element holder  503  is orthogonal to the optical axis, the image capturing element holder  503  is tilted relative to the surface orthogonal to the optical axis as illustrated in  FIG. 4C . In the state illustrated in  FIG. 4B , the sealing member  502  seals the gap between the image capturing element holder  503  and the tilt base  501 . In addition, also in the state illustrated in  FIG. 4C , the sealing member  502  deforms to seal the gap between the image capturing element holder  503  and the tilt base  501 . 
     As described above, the sealing member  502  seals the gap between the image capturing element holder  503  and the tilt base  501  irrespective of a tilting angle of the image capturing element holder  503 . This makes it possible to prevent foreign matters from entering the lens barrel  4  and the image capturing element unit  5 . Further, since the sealing member  502  is formed of a light-shielding material, it is also possible to prevent unnecessary light from entering the image capturing element  516  from the gap between the image capturing element holder  503  and the tilt base  501 . 
     The stepping motor is used as the driving member in the present exemplary embodiment. Alternatively, an ultrasonic motor may be used. 
     In the present exemplary embodiment, the sealing member  502  is bonded to the tilt base  501 . Alternatively, the sealing member  502  may be bonded to the image capturing element holder  503  and may be pressurized by the tilt base  501  because it is sufficient for the sealing member  502  to be fixed to any one of the tilt base  501  and the image capturing element holder  503 . 
     An imaging apparatus according to a second exemplary embodiment is described below with reference to  FIG. 5 .  FIG. 5  is a cross-sectional view of the image capturing element unit  5  according to the second exemplary embodiment. In the present exemplary embodiment, a basic configuration is similar to the basic configuration of the first exemplary embodiment except for a shape of a sealing member  200 . The configuration in the second exemplary embodiment is similar to the configuration of the first exemplary embodiment except for the sealing member  200 , and description of similar parts is therefore omitted. 
     The sealing member  200  seals the gap between the image capturing element holder  503  and the tilt base  501 . The sealing member  200  is fixed to the tilt base  501  by bonding, and is pressurized toward the tilt base  501  by the image capturing element holder  503 . The sealing member  200  is formed of an elastic light-shielding material such as rubber, and has a bellows shape. The sealing member  200  deforms by tilting of the image capturing element holder  503 . 
     In the second exemplary embodiment, since the sealing member  200  has a bellows shape, it becomes possible to reduce driving load associated with the deformation of the sealing member  200  when the image capturing element holder  503  is tilted. Further, the sealing member  200  seals the gap between the image capturing element holder  503  and the tilt base  501  irrespective of the tilting angle of the image capturing element holder  503 . This makes it possible to prevent foreign matters from entering the lens barrel  4  and the image capturing element unit  5 . Further, since the sealing member  200  is formed of a light-shielding material, it is also possible to prevent unnecessary light from entering the image capturing element  516  from the gap between the image capturing element holder  503  and the tilt base  501 . 
     In the present exemplary embodiment, the sealing member  200  is bonded to the tilt base  501 . Alternatively, the sealing member  200  may be bonded to the image capturing element holder  503  and may be pressurized by the tilt base  501  because it is sufficient for the sealing member  200  to be fixed to any one of the tilt base  501  and the image capturing element holder  503 . 
     An imaging apparatus according to a third exemplary embodiment is described below with reference to  FIG. 6  and  FIG. 7 .  FIG. 6  is an exploded perspective view illustrating a network monitoring camera (hereinafter, referred to as monitoring camera) according to the third exemplary embodiment.  FIG. 7  is an exploded perspective view illustrating an imaging apparatus according to the third exemplary embodiment. In the first exemplary embodiment and the second exemplary embodiment, the dome network camera has been described. In exemplary embodiments in and after the third exemplary embodiment, a network camera in which a lens barrel is detachable from the imaging apparatus is described. 
     As illustrated in  FIG. 6 , the monitoring camera includes a camera body  600  as an example of the imaging apparatus, and a lens barrel  710  attached to the camera body  600 . The lens barrel  710  is detachable from the camera body  600 . 
     The camera body  600  includes a tilt base  30 , an optical filter driving unit  700 , an image capturing element unit  60 , an upper case  70 , and a bottom case  80 . 
     The tilt base  30  serving as a base member includes a mount unit  32  to which the lens barrel  710  may be attached. The mount unit  32  includes three pawls, and the three pawls of the mount unit  32  engage with pawls of the lens barrel  710  to fix the lens barrel  710  to the camera body  600 . Further, the image capturing element unit  60  is fixed to the tilt base  30 . 
     The optical filter driving unit  700  inserts an infrared cut-off filter  701  or a dummy glass  702  into an optical path, or retreats the infrared cut-off filter  701  or the dummy glass  702  from the optical path. The optical filter driving unit  700  inserts the infrared cut-off filter  701  into the optical path in a day mode, and retreats the infrared cut-off filter  701  from the optical path and inserts the dummy glass  702  into the optical path in a night mode. A filter holding frame  703  holds the infrared cut-off filter  701  and the dummy glass  702 . The filter holding frame  703  is held by a guide bar  704  fixed to the tilt base  30  so as to be movable in a direction substantially perpendicular to the optical axis. Rotation of the filter holding frame  703  around the guide bar  704  is regulated by engagement of a guide bar  705  with a U-shaped groove on the filter holding frame  703 . A rack  707  is fixed to the filter holding frame  703  while being biased in an axis direction perpendicular to the optical axis and in a rotation direction by a rack spring (not illustrated), and engages with a screw part of a stepping motor  706 . The rack  707  moves together with the filter holding frame  703  in the direction substantially perpendicular to the optical axis by rotation of the screw part. 
     The upper case  70  and the bottom case  80  are configured so as to cover the optical filter driving unit  700  and the image capturing element unit  60 . Each of the upper case  70  and the bottom case  80  has a rectangular shape, and are fastened to the tilt base  30  to form a housing of the camera body  600 . 
     Next, the image capturing element unit  60  is described with reference to  FIG. 7  to  FIG. 9B .  FIG. 8  is a perspective view illustrating the imaging apparatus according to the third exemplary embodiment.  FIG. 9A  is a cross-sectional view illustrating the imaging apparatus according to the third exemplary embodiment.  FIG. 9B  is a cross-sectional view illustrating the imaging apparatus when the image capturing element is tilted, according to the third exemplary embodiment. 
     The image capturing element unit  60  include an image capturing element holder  602  and a sealing member  601 . 
     The image capturing element holder  602  holds the image capturing element  608  so as to be tiltable to a surface orthogonal to the optical axis. The image capturing element  608  converts an image obtained through the imaging lens into an electronic signal. The image capturing element  608  is soldered to a circuit board  609  that electrically connects the image capturing element  608 , and is bonded to an image capturing element sheet metal  607  by an adhesive (not illustrated). An image capturing element sheet metal  607  attached with the image capturing element  608  and the circuit board  609  is attached to the image capturing element holder  602  by fastening screws  610 . Further, the image capturing element holder  602  is integrally formed with a rotary shaft  620 , and the rotary shaft  620  is supported by a supporting part  31  of the tilt base  30 . A washer  603  is disposed on the rotary shaft  620 . Further, a wave washer  604  is further disposed on one side of the rotary shaft  620 , and biases the image capturing element holder  602  toward the rotary shaft  620 . Further, an optical low-pass filter holder  621  that holds an optical low-pass filter  606  is inserted into the image capturing element holder  602 . 
     The sealing member  601  seals a gap between the image capturing element holder  602  and the tilt base  30 . The sealing member  601  is fixed to the tilt base  30  by fixing members  41  and  42 , and is pressurized toward the tilt base  30  by the image capturing element holder  602 . The sealing member  601  is formed of an elastic light-shielding material such as rubber, and deforms by tilting of the image capturing element holder  602 . 
     A stepping motor  612  serving as a driving member is fixed to the tilt base  30 , and a worm  613  is fixed to a motor shaft by press-fitting, etc. A worm wheel is integrally provided on the image capturing element holder  602 , and engages with the worm  613 . The stepping motor  612  is connected to an FPC (not illustrated), and drives and rotates the worm  613  by energization, to tilt the image capturing element holder  602  and the image capturing element  608 . A tension spring  605  is to remove backlash between the worm  613  and the worm wheel, and is attached to the tilt base  30  and the image capturing element holder  602  to generate biasing force in a tension direction. 
     An initial tilting reference position of the image capturing element holder  602  is determined in such a manner that a voltage output value of a photo interrupter fixed to the tilt base  30  is detected by a detection member integrally provided on the image capturing element holder  602 , and the number of driving pulses of the stepping motor  612  is calculated from a result of the detection. 
     Next, relationship between tilting of the image capturing element holder  602  and the sealing member  601  is described. As illustrated in  FIG. 9A , when the stepping motor  612  is driven in a state where the image capturing element holder  602  is orthogonal to the optical axis, the image capturing element holder  602  is tilted relative to the surface orthogonal to the optical axis as illustrated in  FIG. 9B . In the state illustrated in  FIG. 9A , the sealing member  601  seals the gap between the image capturing element holder  602  and the tilt base  30 . In addition, also in the state illustrated in  FIG. 9B , the sealing member  601  deforms to seal the gap between the image capturing element holder  602  and the tilt base  30 . 
     As described above, the sealing member  601  seals the gap between the image capturing element holder  602  and the tilt base  30  irrespective of a tilting angle of the image capturing element holder  602 . This makes it possible to prevent foreign matters from entering the camera unit. Further, since the sealing member  601  is formed of a light-shielding material, it is also possible to prevent unnecessary light from entering the image capturing element  608  from the gap between the image capturing element holder  602  and the tilt base  30 . 
     An imaging apparatus according to a fourth exemplary embodiment is described with reference to  FIGS. 10A and 10B  and  FIG. 11 . 
       FIG. 10A  is a cross-sectional view illustrating the imaging apparatus according to the fourth exemplary embodiment.  FIG. 10B  is a cross-sectional view illustrating the imaging apparatus when an image capturing element is tilted, according to the fourth exemplary embodiment.  FIG. 11  is a perspective view in a state where a cover is removed from the imaging apparatus according to the fourth exemplary embodiment. A configuration is similar to the configuration of the third exemplary embodiment except for the tilt base  30 , and detailed description of the configuration is therefore omitted. 
     As illustrated in  FIG. 11 , the tilt base  30  according to the fourth exemplary embodiment includes two vent holes  33  as an example of a communication part. Each of the two vent holes  33  is a linear groove straightly extending in a direction of the rotary shaft  620  of the image capturing element holder  602 . The two vent holes  33  are located above the rotary shaft  620  of the image capturing element holder  602 . As illustrated in  FIG. 11 , the vent holes  33  allows inside and outside of the sealing member  601  to communicate with each other. 
     When the image capturing element holder  602  is tilted from the state illustrated in  FIG. 10A  to the state illustrated in  FIG. 10B , a volume inside the sealing member  601  is reduced. At this time, air inside the sealing member  601  is discharged to the outside through the vent holes  33 . This makes it possible to reduce driving load by volume change of the sealing member  601  associated with tilting of the image capturing element  608 . 
     The vent holes  33  may be provided on the sealing member  601 . Further, an air filter or an adhesive may be disposed on each of the vent holes  33 . This makes it possible to prevent foreign matters from entering. 
     An imaging apparatus according to a fifth exemplary embodiment is described below with reference to  FIG. 12 .  FIG. 12  is a perspective view in a state where a cover is removed from the imaging apparatus according to the fifth exemplary embodiment. A configuration is similar to the configuration of the fourth exemplary embodiment except for the tilt base  30 , and detailed description of the configuration is therefore omitted. 
     As illustrated in  FIG. 12 , the tilt base  30  according to the fifth exemplary embodiment includes two vent holes  34  as an example of the communication part. Each of the two vent holes  34  includes a bent portion in a bent shape. Further, the two vent holes  34  are located above the rotary shaft  620  of the image capturing element holder  602 . 
     When the image capturing element holder  602  is tilted, a volume inside the sealing member  601  is reduced. At this time, air inside the sealing member  601  is discharged to the outside through the vent holes  34 . This makes it possible to reduce driving load by volume change of the sealing member  601  associated with tilting of the image capturing element  608 . Further, since each of the vent holes  34  includes the bent shape, it is possible to prevent foreign matters from entering in comparison with a case where the vent holes  34  straightly extend. 
     An imaging apparatus according to a sixth exemplary embodiment is described below with reference to  FIGS. 13A and 13B . 
       FIG. 13A  is a cross-sectional view illustrating the imaging apparatus according to the sixth exemplary embodiment.  FIG. 13B  is a cross-sectional view of the imaging apparatus when an image capturing element is tilted, according to the sixth exemplary embodiment. A configuration is similar to the configuration of the third exemplary embodiment except for a sealing member, and detailed description of the configuration is therefore omitted. 
     A sealing member  901  seals the gap between the image capturing element holder  602  and the tilt base  30 . The sealing member  901  is fixed to the tilt base  30  by the fixing members  41  and  42 , and is pressurized toward the tilt base  30  by the image capturing element holder  602 . The sealing member  901  is formed of an elastic light-shielding material such as rubber, and has a bellows shape. The sealing member  901  deforms by tilting of the image capturing element holder  602 . Further, a height of the sealing member  901  on the tilt base  30  side is lower than the height on the image capturing element holder  602  side. 
     As described above, since the sealing member  901  has a bellows shape in the sixth exemplary embodiment, it is possible to reduce driving load associated with the deformation of the sealing member  901  when the image capturing element holder  602  is tilted. Further, the sealing member  901  seals the gap between the image capturing element holder  602  and the tilt base  30  irrespective of the tilting angle of the image capturing element holder  602 . Accordingly, it is possible to prevent foreign matters from entering the lens barrel and the imaging apparatus. Further, since the sealing member  901  is formed of a light-shielding material, it is also possible to reduce unnecessary light from entering the image capturing element  608  from the gap between the image capturing element holder  602  and the tilt base  30 . 
     Further, since the height of the sealing member  901  on the tilt base  30  side is lower than the height on the image capturing element holder  602  side, it is possible to further reduce the driving load associated with the deformation of the sealing member  901  when the image capturing element holder  602  is tilted. 
     The configuration of the present invention is not limited to the configurations exemplified in the respective exemplary embodiments, and materials, shapes, dimensions, forms, numbers, installation positions, etc. may be appropriately modified without departing from the scope of the present invention. 
     While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention 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.