Patent Publication Number: US-2023161231-A1

Title: Light receiving apparatus

Description:
This application is a continuation application of U.S. patent application Ser. No. 16/268,830, filed Feb. 6, 2019, which is a continuation application of U.S. patent application Ser. No. 14/854,808, filed Sep. 15, 2015 (now U.S. Pat. No. 10,237,457, issued Mar. 19, 2019), which is a continuation application, filed under 35 U.S.C. § 111(a), of International Application PCT/JP2014/001157, filed Mar. 3, 2014, which claims the priority benefit of Japanese Patent Application 2013-054441, filed Mar. 15, 2013, the disclosures of which are hereby incorporated by reference in their entirety. 
    
    
     BACKGROUND 
     1. Technical Field 
     The present invention relates to a light receiving apparatus. 
     2. Related Art 
     A camera is known in which a mirror box supporting an imaging element is supported on a main frame that is the main structure of the camera body by a shock resistant support member.
     Patent Document 1: Japanese Patent Application Publication No. 2005-215014   

     However, there is a problem that components to which the optical elements are secured are prone to receiving stress from the outside. 
     SUMMARY 
     According to a first aspect of the present invention, provided is a light receiving apparatus comprising a first light receiving unit; a body to which the first light receiving unit is secured; a first exterior portion that covers at least a portion of the body; and a mount that is capable of having an interchangeable lens attached thereto, to which the body and the first exterior portion are secured. 
     The summary clause does not necessarily describe all necessary features of the embodiments of the present invention. The present invention may also be a sub-combination of the features described above. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a perspective view schematically showing the outer appearance of an imaging device  10 . 
         FIG.  2    is an exploded perspective view schematically showing the assembly of the imaging device  10 . 
         FIG.  3    is an exploded perspective view schematically showing the assembly of the body  100 , the body-side mount  200 , and the front cover  300 . 
         FIG.  4    is an exploded perspective view of the imaging device  10 . 
         FIG.  5    is a cross-sectional view obtained by cutting the imaging device  10  in the xy plane. 
         FIG.  6    is an exploded perspective view schematically showing assembly of the front cover  300 , the top cover  400 , the back cover  500 , and the suspension ring  600 . 
         FIG.  7    is an exploded perspective view showing a state in which the suspension ring  600  is positionally fixed to the top cover  400 . 
         FIG.  8    is an exploded perspective view schematically showing the assembly of the front cover  300 , the back cover  500 , and a tripod base  700 . 
         FIG.  9    is a cross-sectional view of a yz cross section schematically showing a state in which the tripod base  700  is assembled with the front cover  300  and the back cover  500 . 
         FIG.  10    is a perspective view of a portion of the back cover  500 . 
         FIG.  11    is an exploded perspective view schematically showing another assembly example of the tripod base assembly. 
         FIG.  12    is an exploded perspective view schematically showing another assembly example of the tripod base assembly. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     Hereinafter, some embodiments of the present invention will be described. The embodiments do not limit the invention according to the claims, and all the combinations of the features described in the embodiments are not necessarily essential to means provided by aspects of the invention. 
       FIG.  1    is a perspective view schematically showing the outer appearance of an imaging device  10 .  FIG.  1    mainly shows the structural components of the imaging device  10 . The imaging device  10  is a camera body of a single-lens reflex camera. The imaging device  10  includes a body  100 , a body-side mount  200 , a front cover  300 , a top cover  400 , a back cover  500 , a suspension ring  600 , and a substrate cover  800 . 
     As described further below, an imaging unit is secured to the body  100 . The body-side mount  200  has an interchangeable lens attached thereto. When describing the configuration of the imaging device  10 , the direction along the optical axis of the interchangeable lens apparatus is defined as the z axis direction. In other words, the direction of an incident subject light beam is defined as the z axis direction. The direction in which the subject light beam is incident is defined as the negative z axis direction, and the opposite of this direction is defined as the positive z axis direction. Furthermore, the directions shown in  FIG.  1    are defined as the x axis direction and the y axis direction. The x axis, the y axis, and the z axis form an orthogonal right-handed coordinate system. There may be cases where the positive z axis direction is referred to as “forward” or “toward the front.” Furthermore, there may be cases where the negative z axis direction is referred to as “backward” or “toward the back.” There may be cases where the positive y axis direction is referred to as “upward” or “toward the top.” There may be cases where the negative y axis direction is referred to as “downward” or “toward the bottom.” 
       FIG.  2    is an exploded perspective view schematically showing the assembly of the imaging device  10 .  FIG.  2    schematically shows the assembly of the body  100 , the body-side mount  200 , the front cover  300 , the top cover  400 , and the back cover  500 . 
     The following is a basic description of the structure of the imaging device  10 . The front cover  300  covers at least a portion of the body  100 . The body  100  is substantially covered by the front cover  300 , the top cover  400 , and the back cover  500 . The front cover  300 , the top cover  400 , and the back cover  500  are formed of resin. The front cover  300 , the top cover  400 , and the back cover  500  are formed by resin molding. The body-side mount  200  is formed of metal. The body-side mount  200  is a mount ring shaped as a ring. The body  100  is formed of resin. 
     As described further below, the body-side mount  200  is secured to the body  100 , along with the front cover  300 , for example. By securing the body-side mount  200  to the front cover  300 , the stiffness of the position on the front cover  300  where the body-side mount  200  is secured is increased. Accordingly, the front cover  300  is secured at a position on the body  100  that has high stiffness. The body  100  is not secured to any of the front cover  300 , the top cover  400 , and the back cover  500  at any other location. The front cover  300 , the top cover  400 , and the back cover  500  have a monocoque structure. The front cover  300 , the top cover  400 , and the back cover  500  are connected to each other by a spigot structure at contact surfaces. Accordingly, the stress placed on any one of the front cover  300 , the top cover  400 , and the back cover  500  can be received by the entire structure including the front cover  300 , the top cover  400 , and the back cover  500 , and the stress is transferred in a manner to be focused on the portion of the body  100  having increased stiffness due to the securing of the body-side mount  200 . Therefore, the effect that the stress placed on any one of the front cover  300 , the top cover  400 , and the back cover  500  has on the positioning accuracy of the imaging unit secured to the body  100  can be reduced. 
       FIG.  3    is an exploded perspective view schematically showing the assembly of the body  100 , the body-side mount  200 , and the front cover  300 . 
     The body  100  has an overall box shape. The body  100  includes a front surface  101  and a back surface  102  that is on the opposite side of the front surface  101 . The back surface  102  is positioned farther in the negative z axis direction than the front surface  101 . 
     An imaging unit  160 , which is described further below, is secured to the back surface  102  of the body  100 . Specifically, a bracket  170  is secured to the back surface  102  of the body  100 . For example, the bracket  170  is fastened to the body  100  on the back surface  102 . The imaging unit  160  described further below is secured to the bracket  170 . In addition to the imaging unit  160 , a mirror unit, a shutter unit, a finder unit, a focal point detection unit, and the like are secured to the body  100 . The finder unit is secured to the top surface  104  of the body  100 . The focal point detection unit is secured to the bottom surface  105 , which is a surface of the body  100  on the side opposite the top surface  104 . A power supply unit  840  that is described further below and various manipulation components are attached to the front cover  300 . 
     The body  100  includes a securing section  110  to which the body-side mount  200  is secured. The securing section  110  protrudes in the positive z axis direction beyond the front surface  101 . The securing section  110  has a first surface  150  that protrudes in the positive z axis direction beyond a second surface  158  of the front surface  101 , which is parallel to the xy plane. The securing section  110  has a substantially circular shape in the xy plane. The securing section  110  has a substantially cylindrical shape. 
     A recessed portion  112 , a recessed portion  114 , and a recessed portion  116  are formed in the first surface  150  of the securing section  110 . The recessed portion  112  has a floor portion  142 . The recessed portion  114  has a floor portion  144 . The recessed portion  116  has a floor portion  146 . The first surface  150  is positioned farther in the positive z axis direction than the floor portion  142 , the floor portion  144 , and the floor portion  146 . 
     A convex portion  113  is formed between the recessed portion  112  and the recessed portion  114  in the securing section  110 . A convex portion  115  is formed between the recessed portion  114  and the recessed portion  116 . A convex portion  111  is formed between the recessed portion  116  and the recessed portion  112 . The first surface  150  forms a top surface  151  of the convex portion  111 , a top surface  153  of the convex portion  113 , and a top surface  155  of the convex portion  115 . 
     A hole  121  is formed on the top surface  151  of the convex portion  111 . A hole  123  is formed on the top surface  153  of the convex portion  143 . A hole  125  is formed on the top surface  155  of the convex portion  145 . A screw  231  is inserted through the hole  121 . A screw  233  is inserted through the hole  123 . A screw  235  is inserted through the hole  125 . 
     A hole  122  is formed in the floor portion  142 . A hole  124  is formed in the floor portion  144 . A hole  126  is formed in the floor portion  146 . A screw  232  is inserted through the hole  122 . A screw  234  is inserted through the hole  124 . A screw  236  is inserted through the hole  126 . 
     The body-side mount  200  has a mounting surface  201  that is the surface on which the interchangeable lens is attached, a mount securing surface  203  that is the surface on the opposite side from the mounting surface  201 , a side surface  202  that is the surface between the mounting surface  201  and the mount securing surface  203 , and a side surface  204  that is the surface on the opposite side from the side surface  202 . 
     A hole  221 , a hole  222 , a hole  223 , a hole  224 , a hole  225 , and a hole  226  are formed in the body-side mount  200 . The hole  221 , the hole  222 , the hole  223 , the hole  224 , the hole  225 , and the hole  226  penetrate from the lens mounting surface  201  to the mount securing surface  203 . The hole  221 , the hole  222 , the hole  223 , the hole  224 , the hole  225 , and the hole  226  are through-holes that penetrate from the lens mounting surface  201  to the mount securing surface  203  in the z axis direction. 
     The front cover  300  has a front surface  301 , a side portion  310  that protrudes in the positive z axis direction from the front surface  301  and surrounds the securing section  110 , and a flat surface portion  340  that is parallel to the xy plane following the side portion  310 . The flat surface portion  340  has an opening  330 . The opening  330  is substantially circular in the xy plane. The diameter of the opening  330  is larger than the outer diameter of the securing section  110  in the xy plane. 
     The front cover  300  has a front cover-side fastening portion  302  that protrudes from the side portion  310  toward the inside of the opening  330 . The front cover  300  has a front cover-side fastening portion  304  that protrudes from the side portion  310  toward the inside of the opening  330 . The front cover  300  has a front cover-side fastening portion  306  that protrudes from the side portion  310  toward the inside of the opening  330 . A hole  322  is formed in the front cover-side fastening portion  302 . A hole  324  is formed in the front cover-side fastening portion  304 . A hole  326  is formed in the front cover-side fastening portion  306 . The hole  322  is a through-hole. The hole  324  is a through-hole. The hole  326  is a through-hole. The screw  232  is inserted through the hole  322 . The screw  234  is inserted through the hole  324 . The screw  236  is inserted through the hole  326 . When assembling the body-side mount  200 , the front cover  300 , and the body  100 , the screw  232  is inserted through the hole  322 , the screw  234  is inserted through the hole  324 , and the screw  236  is inserted through the hole  326 . 
     The front cover-side fastening portion  302  is housed in the recessed portion  112 . The front cover-side fastening portion  304  is housed in the recessed portion  114 . The front cover-side fastening portion  306  is housed in the recessed portion  116 . The surface  332  of the front cover-side fastening portion  302  is a surface that is on the opposite side from the surface facing the floor portion  142  of the recessed portion  112 , when the front cover-side fastening portion  302  is being housed in the recessed portion  112 . The surface  334  of the front cover-side fastening portion  304  is a surface that is on the opposite side from the surface facing the floor portion  144  of the recessed portion  114 , when the front cover-side fastening portion  304  is being housed in the recessed portion  114 . The surface  336  of the front cover-side fastening portion  306  is a surface that is on the opposite side from the surface facing the floor portion  146  of the recessed portion  116 , when the front cover-side fastening portion  306  is being housed in the recessed portion  116 . A hole  322  is formed in the surface  332  of the front cover-side fastening portion  302 . A hole  324  is formed in the surface  334  of the front cover-side fastening portion  304 . A hole  326  is formed in the surface  336  of the front cover-side fastening portion  306 . 
     In a state where the front cover-side fastening portion  302  is housed in the recessed portion  112 , the front cover-side fastening portion  304  is housed in the recessed portion  114 , and the front cover-side fastening portion  306  is housed in the recessed portion  116 , the first surface  150 , the surface  332 , the surface  334 , and the surface  336  form a flat surface. Specifically, the top surface  151  of the convex portion  111  of the body  100 , the top surface  153  of the convex portion  113  of the body  100 , the top surface  155  of the convex portion  115  of the body  100 , the surface  332  of the front cover-side fastening portion  302 , the surface  334  of the front cover-side fastening portion  304 , and the surface  336  of the front cover-side fastening portion  306  form a flat surface that is parallel to the xy plane. In other words, the flat surface including the top surface  151 , the top surface  153 , the top surface  155 , the surface  332 , the surface  334 , and the surface  336  is parallel to the xy plane. In a state where the body-side mount  200  is in contact with the flat surface formed by the first surface  150 , the surface  332 , the surface  334 , and the surface  336 , the front cover  300  and the body  100  are fastened thereto by the screw  232 , the screw  234 , and the screw  236 . Specifically, in a state where the mount securing surface  203  of the body-side mount  200  is in contact with the flat surface formed by the first surface  150 , the surface  332 , the surface  334 , and the surface  336 , the body-side mount  200 , the front cover  300 , and the body  100  are fastened together. 
     In a state where the front cover-side fastening portion  302  is housed in the recessed portion  112 , the front cover-side fastening portion  304  is housed in the recessed portion  114 , and the front cover-side fastening portion  306  is housed in the recessed portion  116 , the hole  322  is positionally fixed at the position of the hole  122  in the xy plane, the hole  324  is positionally fixed at the position of the hole  124  in the xy plane, and the hole  326  is positionally fixed at the position of the hole  126  in the xy plane. The state where the front cover-side fastening portion  302  is housed in the recessed portion  112 , the front cover-side fastening portion  304  is housed in the recessed portion  114 , and the front cover-side fastening portion  306  is housed in the recessed portion  116  may be referred to as a state in which the front cover  300  is positionally fixed relative to the body  100 . 
     In the body-side mount  200 , the hole  221  is positioned at a position corresponding to the hole  121 . The hole  222  is positioned at a position corresponding to the hole  122 . The hole  223  is positioned at a position corresponding to the hole  123 . The hole  224  is positioned at a position corresponding to the hole  124 . The hole  225  is positioned at a position corresponding to the hole  125 . The hole  226  is positioned at a position corresponding to the hole  126 . 
     For example, when the body-side mount  200  and the body  100  are positionally fixed such that the hole  221  is positionally fixed at the position of the hole  121  in the xy plane and the hole  224  is positionally fixed at the position of the hole  124  in the xy plane, the hole  222  is positionally fixed at the position of the hole  122  in the xy plane, the hole  223  is positionally fixed at the position of the hole  123  in the xy plane, the hole  225  is positionally fixed at the position of the hole  125  in the xy plane, and the hole  226  is positionally fixed at the position of the hole  126  in the xy plane. The state where the hole  221 , the hole  222 , the hole  223 , the hole  224 , the hole  225 , and the hole  226  of the body-side mount  200  are respectively positionally fixed at the positions of the hole  121 , the hole  122 , the hole  123 , the hole  124 , the hole  125 , and the hole  126  may be referred to as a state in which the body-side mount  200  is positionally fixed relative to the body  100 . 
     In a state where the front cover  300  is positionally fixed relative to the body  100  and the body-side mount  200  is positionally fixed relative to the body  100 , the screw  231  is inserted through the hole  221  and the hole  121 , the screw  233  is inserted through the hole  223  and the hole  123 , the screw  235  is inserted through the hole  225  and the hole  125 , and the body-side mount  200  and body  100  are attached directly to each other by the screw  231 , the screw  233 , and the screw  235 . 
     Furthermore, in the state where the front cover  300  is positionally fixed relative to the body  100  and the body-side mount  200  is positionally fixed relative to the body  100 , the screw  232  is inserted through the hole  222 , the hole  322 , and the hole  122 , the screw  234  is inserted through the hole  224 , the hole  324 , and the hole  124 , the screw  236  is inserted through the hole  226 , the hole  326 , and the hole  126 , and body-side mount  200 , the front cover  300 , and the body  100  are fastened by the screw  232 , the screw  234 , and the screw  236 . In a state where the front cover-side fastening portion  302 , the front cover-side fastening portion  304 , and the front cover-side fastening portion  306  are sandwiched by the body-side mount  200  and the body  100  in the z axis direction in this manner, the body-side mount  200  and the body  100  are fastened together by the screw  232 , the screw  234 , and the screw  236 . In the state where the front cover  300  is sandwiched by the body-side mount  200  and the body  100  in a prescribed direction in this manner, the body-side mount  200  and the body  100  are fastened together by the screws. Accordingly, the front cover  300  is secured in a state of being sandwiched by the body-side mount  200  and the body  100  in the prescribed direction. 
     In the xy plane, the hole  221 , the hole  222 , the hole  223 , the hole  224 , the hole  225 , and the hole  226  are positioned in the same circle. Specifically, in the xy plane, the hole  221 , the hole  222 , the hole  223 , the hole  224 , the hole  225 , and the hole  226  are formed at positions every 60 degrees around the optical axis. The hole  221 , the hole  223 , and the hole  225  are positioned at the vertices of an equilateral triangle. The hole  222 , the hole  224 , and the hole  226  are positioned at the vertices of an equilateral triangle. 
     In this way, the body-side mount  200  is fastened in its entirety to the body  100  at six points in the same circle. Specifically, the body-side mount  200  is directly fastened to the body  100  at three points in the same circle, and is also fastened to the body  100  with the front cover  300  interposed therebetween at another three points in the same circle. The front cover  300  is fastened to the body-side mount  200  at three points, and is also fastened to the body  100  at the same three points. 
     In this way, the front cover  300  and the body  100  are secured to the body-side mount  200 , and therefore it is difficult for stress to be transferred from the front cover  300  to the body  100 . For example, the body-side mount  200 , the front cover  300 , and the body  100  are fastened together, and therefore it is difficult for twisting stress to occur in the body  100 . Therefore, the body  100  is more difficult to deform when stress is placed on the front cover  300 . Accordingly, it is possible to restrict the reduction in the positioning accuracy of the imaging unit  160 , which is an example of a light receiving unit. 
     The front cover-side fastening portion  302 , the front cover-side fastening portion  304 , and the front cover-side fastening portion  306  of the front cover  300  are examples of exterior-side fastening portions that are fastened to the body-side mount  200 . The screw  232 , the screw  234 , and the screw  236  are examples of first fastening members that fasten together the body-side mount  200 , the fastening portion of the front cover  300 , and the body  100 . The screw  231 , the screw  233 , and the screw  235  are examples of second fastening members that fasten the body  100  to the body-side mount  200  without fastening the body  100  to the front cover  300 . 
     The hole  122  positioned in the floor portion of the recessed portion  112  in the securing section  110  is an example of a first fastening portion that fastens together the body-side mount  200  and the front cover  300  using a screw. The hole  121  positioned in the convex portion  111  of the securing section  110  is an example of a second fastening portion for fastening to the body-side mount  200  without fastening to the front cover  300 . In other words, in a state where a first fastening portion of the body  100  is positioned at the bottom of a recessed portion housing an external fastening portion and the external fastening portion is housed in the recessed portion, the body  100  is fastened together with the body-side mount  200  by the screws. 
     As described above, in a state where the front cover-side fastening portion  302 , the front cover-side fastening portion  304 , and the front cover-side fastening portion  306  are respectively housed in the recessed portion  112 , the recessed portion  114 , and the recessed portion  116 , the first surface  150  of the body  100  and the surface  332 , the surface  334 , and the surface  336  of the front cover  300  form a flat surface contacting the mount securing surface  203  of the body-side mount  200 . However, the first surface  150  of the body  100  and the surface  332 , the surface  334 , and the surface  336  of the front cover  300  need not form a flat surface. The surface shape of the surface formed by the first surface  150  of the body  100  and the surface  332 , the surface  334 , and the surface  336  of the front cover  300  may have a shape corresponding to the surface shape of the mount securing surface  203  of the body-side mount  200 . A portion of each of the front cover-side fastening portion  302 , the front cover-side fastening portion  304 , and the front cover-side fastening portion  306  may be housed in the corresponding recessed portion  112 , recessed portion  114 , and recessed portion  116 . In a state where a portion of each of the front cover-side fastening portion  302 , the front cover-side fastening portion  304 , and the front cover-side fastening portion  306  is housed in the corresponding recessed portion  112 , recessed portion  114 , and recessed portion  116 , the surface  332  of the front cover-side fastening portion  302 , the surface  334  of the front cover-side fastening portion  304 , and the surface  336  of the front cover-side fastening portion  306  may protrude in the positive z axis direction from the first surface  150 . Accordingly, at least a portion of each of the front cover-side fastening portion  302 , the front cover-side fastening portion  304 , and the front cover-side fastening portion  306  may be housed in the corresponding recessed portion  112 , recessed portion  114 , and recessed portion  116 . 
     If the front cover  300  is at a location near the location on the body  100  where the body-side mount  200  is secured, the front cover  300  may be secured to the body  100 . For example, a location of the front cover  300  that protrudes in the positive z axis direction beyond the front surface  301  may be secured to a location on the body  100  that protrudes in the positive z axis direction beyond the front surface  301 . For example, the side portion  310  of the front cover  300  may be secured to the securing section  110 . As another example, if the front cover  300  has a surface that is substantially parallel to a secure surface that is secured to the body  100  by the body-side mount  200 , e.g. the first surface  150 , and that is positioned farther on the optical axis side than the front surface  301  in the xy plane, this surface may be secured to the body  100 . For example, the surface  308  of the front cover  300  may be fastened to the surface  158  of the front surface  101 . 
     If the front cover  300  is distanced from the location on the body  100  where the body-side mount  200  is secured by less than or equal to a predetermined distance, the front surface  301  of the front cover  300  and the body  100  may be secured. In this case, the position where the front cover  300  and the body  100  are secured is preferably within a range that forms a rectangle surrounding and in contact with the outer ring of the body-side mount  200 . Specifically, when the distance from the optical axis to the outer ring of the body-side mount  200  in the xy plane is r, the distance between the optical axis and the position at which the front cover  300  and the body  100  are secured is preferably less than or equal to a value obtained as the product of r and the square root of 2. Also, if the side portion  310  of the front cover  300  is secured to the body  100 , the distance between the optical axis and the position at which the front cover  300  and the body  100  are secured is preferably less than or equal to a value obtained as the product of r and the square root of 2. 
     The following is a basic description of the mounting mechanism for mounting an interchangeable lens on the body-side mount  200 . The interchangeable lens is mounted on the body-side mount  200  by a bayonet mechanism. The body-side mount  200  has a claw portion  281  and a claw portion  282 . The claw portion  281  and the claw portion  282  are used for mounting the interchangeable lens on the body-side mount  200 . The body-side mount  200  includes three claw portions used for mounting the interchangeable lens on the mounting surface  201 . The claw portion  281  and the claw portion  282  shown in  FIG.  3    are two of the three claw portions of the body-side mount  200 . The three claw portions of the body-side mount  200  may be simply referred to as the claw portions. 
     The claw portion  281  and the claw portion  282  are provided on the side surface  204  of the body-side mount  200 . The claw portion  281  and the claw portion  282  protrude toward the inside of the opening  230  of the body-side mount  200 . A stepped portion  284  is formed in the side surface  204  of the body-side mount  200  between the claw portion  281  and the claw portion  282  that is adjacent to the claw portion  281 . The stepped portion  284  is a portion in the side surface  204  that does not protrude toward the inside of the opening  230 . Stepped portions that are the same as the stepped portion  284  are formed between adjacent claw portions in the side surface  204  of the body-side mount  200 . Accordingly, three stepped portions are formed in the side surface  204  of the body-side mount  200 . 
     The interchangeable lens includes a lens-side mount for mounting on the body-side mount  200 . The lens-side mount of the interchangeable lens includes three claw portions for mounting the interchangeable lens on the body-side mount  200 . The three claw portions of the lens-side mount of the interchangeable lens may be referred to as lens-side claw portions. 
     When mounting the interchangeable lens on the body-side mount  200 , in a state where an attachment mark  394  provided on the front cover  300  is aligned around the z axis with an attachment mark provided on the interchangeable lens, the interchangeable lens is inserted into the opening  230  of the body-side mount  200 . In a state where the attachment mark of the interchangeable lens and the attachment mark  394  are aligned, the lens-side claw portions of the interchangeable lens are positioned at the stepped portions  284  of the body-side mount  200  in the xy plane. 
     Accordingly, in a state where the attachment mark of the interchangeable lens and the attachment mark  394  are aligned, when the interchangeable lens is inserted into the opening  230  of the body-side mount  200 , the lens-side claw portions of the interchangeable lens pass through the stepped portions  284  of the body-side mount  200  in the negative z axis direction to be inserted up to a position behind the corresponding claw portions. In this state, when the interchangeable lens is rotated around the z axis, the three lens-side claw portions of the interchangeable lens enter behind the corresponding claw portions of the body-side mount  200 . The rotation of the interchangeable lens around the z axis is limited by a portion of the camera mount of the interchangeable lens contacting the end portions  288  of the claw portions  281 . 
     A flat spring is secured on the mounting surface  201  of the body-side mount  200  to realize firm contact between the mounting surface  201  and the mounting surface of the lens-side mount, as a result of being sandwiched between the mount securing surface  203  and the first surface  150  of the body  100 . The flat spring has a protruding portion that protrudes in the negative z axis direction beyond the surface of the mount securing surface  203  on which the flat spring is secured, and the lens-side mount of the interchangeable lens is biased in the negative z axis direction by the protruding portion of the flat spring. As a result, the interchangeable lens is restricted from moving in the z axis direction relative to the body-side mount  200 . The mounting surface of the lens-side mount of the interchangeable lens is in firm contact when touching the mounting surface  201  of the body-side mount  200 . In this way, the interchangeable lens is mounted on the body-side mount  200  by the bayonet mechanism. 
     The mounting surface  201  is a reference surface for determining a flange back. The flange back is determined according to the distance between the mounting surface  201  and the imaging surface of the imaging element in the z axis direction. 
     A pin hole  290  is formed penetrating through the body-side mount  200  from the mounting surface  201  of the body-side mount  200  to the mount securing surface  203 . A lock pin for limiting the rotation of the interchangeable lens relative to the body-side mount  200  is inserted through the pin hole  290 . The lock pin is biased in the positive z axis direction by the bias force of a spring. The lock pin protrudes from the mounting surface  201  in the positive z axis direction into the pin hole  290  when the body-side mount  200  is secured to the body  100 . A pin hole is formed in the lens-side mount of the interchangeable lens. A portion of the lock pin protruding in the positive z axis direction from the mounting surface  201  is inserted into the pin hole of the interchangeable lens. By inserting the portion of the lock pin into the pin hole of the interchangeable lens, the rotation of the interchangeable lens mounted on the body-side mount  200  around the z axis is limited. 
     An opening  390  for exposing a lock release button to the outside is formed in the front cover  300 . When the lock release button is pressed, the lock pin moves in conjunction with the movement of the lock release button to be displaced in the negative z axis direction against the bias force of the spring. When the entire lock pin is displaced beyond the mounting surface  201  in the negative z axis direction, it is possible for the interchangeable lens to rotate around the x axis. 
     When the interchangeable lens is mounted on the body-side mount  200 , the light that has passed through the interchangeable lens can pass further inward than the claw portions of the body-side mount  200 . The claw portions of the body-side mount  200  determine an opening diameter of the mount. The opening diameter of the mount is determined to be a value that is twice the distance between a claw portion and the z axis in the xy plane. 
     The attachment mark  394  may be colored a different color than the color around the attachment mark  394  in the front cover  300 . The attachment mark  394  is provided on the front cover  300 . However, a similar attachment mark may be provided on the body-side mount  200 . For example, an attachment mark may be formed on the mounting surface  201  of the body-side mount  200 . The attachment mark  394  is formed at a location that is depressed beyond the mounting surface  201  of the body-side mount  200 . 
     In the above example, the hole  221 , the hole  222 , the hole  223 , the hole  224 , the hole  225 , and the hole  226  of the body-side mount  200  are positioned in the same circle in the xy plane. The hole  222 , the hole  224 , and the hole  226  may be arranged in the same circle. The hole  221 , the hole  223 , and the hole  225  may be positioned in the same circle. Here, the center of the circle passing through the hole  221 , the hole  223 , and the hole  225  preferably matches the center of the circle passing through the hole  222 , the hole  224 , and the hole  226 . As an example, the diameter of the circle passing through the hole  221 , the hole  223 , and the hole  225  and the diameter of the circle passing through the hole  222 , the hole  224 , and the hole  226  may be the same or may be different. For example, the diameter of the circle passing through the centers of each of the hole  221 , the hole  223 , and the hole  225  and the diameter of the circle passing through the centers of each of the hole  222 , the hole  224 , and the hole  226  may be the same or may be different. If the diameter of the circle passing through the hole  221 , the hole  223 , and the hole  225  is different from the diameter of the circle passing through the hole  222 , the hole  224 , and the hole  226 , the diameter of the circle passing through the hole  222 , the hole  224 , and the hole  226  may be greater than the diameter of the circle passing through the hole  221 , the hole  223 , and the hole  225 . It should be noted that the positional relationship of the hole  221 , the hole  222 , the hole  223 , the hole  224 , the hole  225 , and the hole  226  is not limited to this example. As another example, the hole  221 , the hole  222 , the hole  223 , the hole  224 , the hole  225 , and the hole  226  may be positioned at any position in the mounting surface  201 , as long as these holes are formed in the mounting surface  201 . 
     The hole  322  need not be a through-hole. In this case, the hole  322  may be a female thread. The hole  322  may be a female thread that penetrates through the front cover-side fastening portion  302 . The hole  324  need not be a through-hole. In this case, the hole  324  may be a female thread. The hole  324  may be a female thread that penetrates through the front cover-side fastening portion  304 . The hole  326  need not be a through-hole. In this case, the hole  326  may be a female thread. The hole  326  may be a female thread that penetrates through the front cover-side fastening portion  306 . If the hole  322  is not a through-hole, the body  100  need not include the hole  122 . If the hole  324  is not a through-hole, the body  100  need not include the hole  124 . If the hole  326  is not a through-hole, the body  100  need not include the hole  126 . 
     If the hole  322  is a female thread, the body-side mount  200  and the front cover-side fastening portion  302  may be fastened by the screw  232 . In this case the front cover-side fastening portion  302  and the body  100  need not be fastened. If the hole  324  is a female thread, the body-side mount  200  and the front cover-side fastening portion  304  may be fastened by the screw  234 . In this case the front cover-side fastening portion  304  and the body  100  need not be fastened. If the hole  326  is a female thread, the body-side mount  200  and the front cover-side fastening portion  306  may be fastened by the screw  236 . In this case the front cover-side fastening portion  306  and the body  100  need not be fastened. 
     The hole  121 , the hole  122 , the hole  123 , the hole  124 , the hole  125 , and the hole  126  need not be through-holes. In this case, the hole  121 , the hole  122 , the hole  123 , the hole  124 , the hole  125 , and the hole  126  may be female threads. 
     In the imaging device  10 , the exterior of the imaging device  10  is formed by the three covers that are the front cover  300 , the top cover  400 , and the back cover  500 . However, the exterior of the imaging device  10  may be formed by two covers. If the exterior of the imaging device  10  is formed by two covers, the body  100  is covered by these two covers. The exterior of the imaging device  10  may be formed by four covers. If the exterior of the imaging device  10  is formed by four covers, the body  100  is covered by these four covers. The exterior of the imaging device  10  may be formed by two or more covers. 
     As described above, the body-side mount  200  is formed of metal and the front cover  300  is formed of resin. However, the material forming the body-side mount  200  is not limited to metal, as long as the material used results in the stiffness of the body-side mount  200  being greater than the stiffness of the front cover  300 . For example, the body-side mount  200  may be formed of resin. In the same manner, the material forming the front cover  300  is not limited to resin. For example, the front cover  300  may be formed of metal. 
       FIG.  4    is an exploded perspective view of the imaging device  10 .  FIG.  4    shows an electronic device substrate  820 , a power supply unit  840 , and the imaging unit  160 , along with the body  100 , the front cover  300 , the top cover  400 , and the back cover  500 . 
     The imaging unit  160  includes an imaging element that receives light from a subject. The imaging unit  160  is fastened and secured to the bracket  170 . In this way, the imaging unit  160  is secured to the body  100  via the bracket  170 . 
     An electronic component for processing a signal output from the imaging element of the imaging unit  160  is implemented on the electronic device substrate  820 . The imaging unit  160  and the electronic device substrate  820  are connected via a circuit board such as a flexible print substrate interposed therebetween. 
     The power supply unit  840  supplies power to each component of the imaging device  10 . The power from the power supply unit  840  is supplied to the electronic device substrate  820  via the circuit board such as the flexible print substrate. The power from the power supply unit  840  may be supplied to the imaging unit  160  via the electronic device substrate  820 . 
     The substrate cover  800  is secured to the front cover  300 . The electronic device substrate  820  is secured to the substrate cover  800 . 
     As described above, the front cover  300  is rigidly connected by screws to the securing section  110  of the body  100 . The front cover  300  is not rigidly connected to the body  100  at any location other than the securing section  110 . For example, when stress is placed on the front cover  300 , the stress transferred to the back surface  102  of the body  100  via the substrate cover  800 , the electronic device substrate  820 , and the circuit board is much less than the stress transferred to the securing section  110  of the front surface  101 . The securing section  110  of the body  100  has the body-side mount  200  secured thereto, and therefore the securing section  110  has higher stiffness than the back surface  102 . Accordingly, even when stress is transferred to the securing section  110 , the body  100  does not significantly deform. Therefore, it is possible to significantly reduce the effect on the positioning accuracy of the imaging unit  160  caused by the stress placed on the front cover  300 . 
       FIG.  5    is a cross-sectional view obtained by cutting the imaging device  10  in the xy plane.  FIG.  5    shows the front cover  300 , the top cover  400 , and the back cover  500 . 
     The front cover  300  and the top cover  400  are connected by a spigot structure. At the connecting section  401  connecting the front cover  300  and the top cover  400 , the top cover  400  includes a convex portion  450  that protrudes in the positive z axis direction from the surface facing the front cover  300 . The front cover  300  includes a recessed portion  350  that is recessed in the positive z axis direction from the surface facing the top cover  400 . The front cover  300  and the top cover  400  are connected by engagement between the recessed portion  350  of the front cover  300  and the convex portion  450  of the top cover  400 . 
     The front cover  300  and the back cover  500  are connected by a spigot structure. At the connecting section  402  connecting the front cover  300  and the back cover  500 , the top cover  400  includes a convex portion  460  that protrudes in the negative z axis direction from the surface facing the back cover  500 . The back cover  500  includes a recessed portion  560  that is depressed in the negative z axis direction from the surface facing the top cover  400 . The back cover  500  and the top cover  400  are connected by engagement between the recessed portion  560  of the back cover  500  and the convex portion  460  of the top cover  400 . 
     In a similar manner, at the connecting section  403  connecting the front cover  300  and the top cover  400 , the front cover  300  and the top cover  400  are connected by a spigot structure. In a similar manner, at the connecting section  404  connecting the back cover  500  and the top cover  400 , the back cover  500  and the top cover  400  are connected by a spigot structure. 
     Although not shown in  FIG.  5   , as described above, at the contact surface between the front cover  300  and the back cover  500 , the front cover  300  and the back cover  500  are connected by a spigot structure. In this way, the front cover  300  and the top cover  400  are connected by a spigot structure along the contact surface between the front cover  300  and the top cover  400 . Furthermore, the top cover  400  and the back cover  500  are connected by a spigot structure along the contact surface between the top cover  400  and the back cover  500 . The front cover  300  and the back cover  500  are connected by a spigot structure along the contact surface between the front cover  300  and the back cover  500 . In this way, the front cover  300 , the top cover  400 , and the back cover  500  are connected by spigot structures at the contact surfaces with the other covers. Therefore, when stress is placed on any one of the front cover  300 , the top cover  400 , and the back cover  500 , it is possible to restrict shifting in the direction parallel to the contact surfaces with the other covers. 
     The exterior portion formed by the front cover  300 , the top cover  400 , and the back cover  500  has a monocoque structure for receiving stress. As described above, the front cover  300 , the top cover  400 , and the back cover  500  have contact surfaces that are connected to each other with a spigot structure, and therefore the monocoque structure is preserved despite forming the exterior with a plurality of components such as the front cover  300 , the top cover  400 , and the back cover  500 . 
     The weight of the body  100  is preferably approximately the same as the weight of other components of the imaging device  10 . By making the weight of the body  100  be approximately the same as the weight of the other components of the imaging device  10 , it is possible to attenuate vibration caused by the movement of the shutter, mirror, or the like in the body  100 . The error between the weight of the body  100  and the weight of the other components is preferably no greater than 5%. If the weight of the body  100  differs from the weight of the other components, the body  100  is preferably heavier than the other components. 
       FIG.  6    is an exploded perspective view schematically showing assembly of the front cover  300 , the top cover  400 , the back cover  500 , and the suspension ring  600 .  FIG.  7    is an exploded perspective view showing a state in which the suspension ring  600  is positionally fixed to the top cover  400 . 
     The back cover  500  includes a screw hole  511 , a screw hole  512 , a screw hole  513 , a screw hole  514 , and a screw hole  515 . The screw hole  511 , the screw hole  512 , the screw hole  513 , the screw hole  514 , and the screw hole  515  are each formed along the z axis direction. The top cover  400  includes a screw hole  413 , a screw hole  414 , and a screw hole  415 . The screw hole  413 , the screw hole  414 , and the screw hole  415  are each formed along the z axis direction. The front cover  300  includes a screw hole  311  and a screw hole  312 . The screw hole  311  and the screw hole  312  are each formed along the z axis direction. 
     The top cover  400  and the back cover  500  are fastened by screws in a state where the screw hole  413  and the screw hole  513  are positionally fixed, the screw hole  414  and the screw hole  514  are positionally fixed, and the screw hole  415  and the screw hole  515  are positionally fixed. The front cover  300  and the back cover  500  are fastened by screws in a state where the screw hole  311  and the screw hole  511  are positionally fixed. 
     The suspension ring  600  is secured to the front cover  300  and the back cover  500 . The suspension ring  600  is formed of metal. The suspension ring  600  is a metal fitting for attaching a hanging strap to the imaging device  10 . 
     The suspension ring  600  includes a front-side fastening portion  610 , a back-side fastening portion  620 , a connecting portion  630  that connects the front-side fastening portion  610  and the back-side fastening portion  620 , and a ring portion  640 . The suspension ring  600  is secured in a state where the ring portion  640  protrudes from the opening  480  formed in the top cover  400 . A strap can be attached to the ring portion  640 . The strap may be attached to the ring portion  640  via a metal fitting for attaching a triangular ring or the like to which the strap is attached. 
     The front-side fastening portion  610  is positioned farther in the positive z axis direction than the back-side fastening portion  620 . The front-side fastening portion  610  has a surface that is parallel to the xy plane and extends in the positive y axis direction from the connecting portion  630 . The back-side fastening portion  620  has a surface that is parallel to the xy plane and extends in the negative y axis direction from the connecting portion  630 . The connecting portion  630  extends in the z axis direction. The connecting portion  630  connects a top portion of the front-side fastening portion  610  to a bottom portion of the back-side fastening portion  620 . 
     The front-side fastening portion  610  has a screw hole  612  formed along the z axis direction. The back-side fastening portion  620  has a screw hole  622  formed along the z axis direction. 
     The front cover  300  and the suspension ring  600  are fastened by a screw in a state where the screw hole  312  and the screw hole  612  are positionally fixed. The suspension ring  600  and the back cover  500  are fastened by a screw in a state where the screw hole  622  and the screw hole  512  are positionally fixed. In this way, the front cover  300  and the back cover  500  are secured via the suspension ring  600 . 
     As described above, the top cover  400  and the back cover  500  have a contact surface that is substantially orthogonal to the z axis direction. The top cover  400  and the back cover  500  are fastened by screws with a fastening axis along the z axis direction. In the same manner, the front cover  300  and the back cover  500  have a contact surface that is substantially orthogonal to the z axis direction. The front cover  300  and the back cover  500  are fastened by screws with a fastening axis along the z axis direction. Therefore, it is possible to further restrict sliding of the contact surfaces. Although not shown in  FIGS.  6  and  7   , the front cover  300  and the top cover  400  are fastened by screws with a fastening axis along the z axis direction. 
     As described above, the front cover  300 , the top cover  400 , and the back cover  500  have fastening axes orthogonal to the contact surfaces therebetween, and therefore the stress applied to any one of these covers can be transferred efficiently to the other covers. Therefore, it is possible to preserve the monocoque structure despite forming the exterior portion with a plurality of components such as the front cover  300 , the top cover  400 , and the back cover  500 . Accordingly, it is possible to diffuse the stress placed on any one of the front cover  300 , the top cover  400 , and the back cover  500  to other covers. For example, when stress is placed on the back cover  500  from the outside, the stress placed on the back cover  500  from the outside can be diffused to the front cover  300  and the top cover  400 . Accordingly, it is possible to decrease the stress value received by the back cover  500 . In this way, it is possible to restrict the focusing of stress on a single one of the front cover  300 , the top cover  400 , and the back cover  500 , and therefore it is possible to restrict damage to each cover. Accordingly, it is possible to increase the shock resistance. Furthermore, it is possible to omit support members, and therefore the imaging device  10  can be made lighter weight. Yet further, even if there is a significant error in the dimensions of the front cover  300 , the top cover  400 , and the back cover  500 , it is possible to remove gaps between the covers at the contact surfaces therebetween. Therefore, it is possible to increase the quality of the outside appearance of the imaging device  10 . 
     One end of the suspension ring  600  is secured to the front cover  300 , and the other end of the suspension ring  600  is secured to the back cover  500 . Stress is placed on the suspension ring  600  by the attached strap, but since the suspension ring  600  is secured to both the front cover  300  and the back cover  500 , it is possible to diffuse the stress placed on the suspension ring  600  to the front cover  300  and the back cover  500 . 
     The screw holes for fastening the front cover  300 , the top cover  400 , and the back cover  500  to each other are provided at the corners when viewing the entire outside appearance of the imaging device  10 . For example, the imaging device  10  has an overall box shape, and the screw hole  511  and the screw hole  512  are provided in the back cover  500  at corners of this box shape. Therefore, the stress can be diffused across two edges and the number of fastening members such as the screws can be reduced. The screw hole  513  and the screw hole  514  are provided at the corners of the finder opening  590  of the top cover  400 . In the top cover  400 , the screw hole  413  and the screw hole  414  are positioned near the accessory shoe  470 . The screw hole  413  and the screw hole  414  are arranged at positions enabling stress to be diffused when stress is placed on the accessory shoe  470  due to mounting of an external accessory. For example, the screw hole  413  and the screw hole  414  are arranged at locations where the stress placed on the accessory shoe  470  from an external accessory is greater than a predetermined value. As another example, the screw hole  413  and the screw hole  414  are arranged near a stress line caused by an external accessory. 
       FIG.  8    is an exploded perspective view schematically showing the assembly of the front cover  300 , the back cover  500 , and a tripod base  700 .  FIG.  9    is a cross-sectional view of a yz cross section schematically showing a state in which the tripod base  700  is assembled with the front cover  300  and the back cover  500 . 
     The front cover  300  includes a rib  381  and a rib  382  on a loading surface  370  on which a portion of the tripod base  700  is loaded. The rib  381  and the rib  382  are distanced from each other in the x axis direction. The rib  381  and the rib  382  extend in a direction toward the position of the securing section  110 . A portion of the tripod base  700  is housed between the rib  381  and the rib  382 . The front cover  300  further includes a rib  383  and a rib  384  that extend toward the securing section  110 . The rib  383  and the rib  384  are positioned between the rib  381  and the rib  382  in the x axis direction. The rib  383  and the rib  384  are positioned between the securing section  110  and the position where the tripod base  700  is secured in the z axis direction. 
     A screw hole  371  and a screw hole  372  are formed in the loading surface  370 . A notched portion  375  having a semicircular shape in the xz plane is formed in the loading surface  370 . 
     In the back cover  500 , a screw hole  573  and a screw hole  574  are formed in a loading surface  570  on which a portion of the tripod base  700  is loaded. The loading surface  570  includes a rib  581  and a rib  582 . The rib  581  and the rib  582  extend in the z axis direction. When the front cover  300  and the back cover  500  are aligned, the rib  581  is adjacent to the rib  381  at a position on the negative x axis direction side of the rib  381 . The rib  582  is adjacent to the rib  382  at a position on the positive x axis direction side of the rib  382 . The height to which the rib  381  and the rib  382  protrude from the loading surface  370  is preferably greater than the height to which the rib  581  and the rib  582  protrude from the loading surface  570 . 
     A notched portion  575  having a semicircular shape in the xz plane is formed in the loading surface  570 . When the front cover  300  and the back cover  500  are aligned, the notched portion  375  and the notched portion  575  form a housing opening  585  that houses the attaching portion  770  for attaching the tripod base  700  to a tripod. 
     A screw hole  701 , a screw hole  702 , a screw hole  703 , and a screw hole  704  are formed in the tripod base  700 . The screw hole  701  corresponds to the screw hole  371 , the screw hole  702  corresponds to the screw hole  372 , the screw hole  703  corresponds to the screw hole  573 , and the screw hole  704  corresponds to the screw hole  574 . Specifically, in a state where the tripod base  700  is sandwiched between the rib  381  and the rib  382  and loaded on the loading surface  370 , the screw hole  701  is positionally fixed at the position of the screw hole  371  and the screw hole  702  is positionally fixed at the position of the screw hole  372 . Furthermore, in a state where the front cover  300  and the back cover  500  are positionally fixed, the screw hole  703  is positionally fixed at the position of the screw hole  573  and the screw hole  704  is positionally fixed at the position of the screw hole  574 . In a state where the front cover  300  and the back cover  500  are aligned, the tripod base  700  is fastened to the front cover  300  by inserting screws through the screw hole  701  and the screw hole  702 . Furthermore, the tripod base  700  is fastened to the back cover  500  by inserting screws through the screw hole  703  and the screw hole  704 . 
     The rib  381  and the rib  382  protrude in the negative z axis direction beyond the edge of the loading surface  370  positioned on the negative z axis direction side. The rib  581  and the rib  582  protrude in the positive z axis direction beyond the edge of the loading surface  570  positioned on the positive z axis direction side. Accordingly, the position at which the front cover  300  and the back cover  500  are connected can be restricted from being displaced in a direction away from the tripod base  700 . 
     In this way, one end of the tripod base  700  is secured to the front cover  300  and the other end of the tripod base  700  is secured to the back cover  500 . Stress is placed on the tripod base  700  by the attached tripod, but since the tripod base  700  is fastened to both the front cover  300  and the back cover  500 , it is possible to diffuse the stress placed on the tripod base  700  to the front cover  300  and the back cover  500 . 
     The front cover  300  includes the rib  381 , the rib  382 , the rib  383 , and the rib  384 , and therefore deformation of the front cover  300  caused by stressed placed thereon via the tripod base  700  can be restricted. In particular, the rib  381 , the rib  382 , the rib  383 , and the rib  384  extend from a position near where the tripod base  700  is secured to a position near the securing section  110 . Therefore, it is possible to restrict localized stress from being focused between the securing section  110  and the position where the tripod base  700  is secured and causing localized bending of the front cover  300 . 
     The length of the tripod base  700  in the z axis direction is greater than the length of the tripod base  700  in the x axis direction. It order to avoid the focusing of stress placed on the tripod base  700 , it is more preferable for the length of the tripod base  700  in the z axis direction to be longer. The tripod base  700  more preferably extends to a position closer to the securing section  110 . 
     When forming the front cover  300  using resin molding, the rib  381 , the rib  382 , the rib  383 , and the rib  384  are preferably formed in a manner to not include welding. In particular, it is preferable that weld lines do not intersect with the extension direction of the rib  381 , the rib  382 , the rib  383 , and the rib  384 . A gate is preferably arranged such that the resin flows parallel to the extension direction of the rib  381 , the rib  382 , the rib  383 , and the rib  384 . A gate faucet is preferably arranged in a mold that is continuous from the securing section  110  to the rib  381 , the rib  382 , the rib  383 , and the rib  384 . A guide wall may be formed to guide the resin to form the rib  381 , the rib  382 , the rib  383 , and the rib  384 . 
       FIG.  10    is a perspective view of a portion of the back cover  500 .  FIG.  10    particularly shows the floor portion and the opening  520  of the back cover  500 . The opening  520  is an opening for exposing the display surface of a display apparatus to the outside form the imaging device  10 . 
     The back cover  500  includes a rib  540  that is positioned below the opening  520 . The rib  540  extends in the x axis direction. The length of the rib  540  in the x axis direction is greater than the length of the opening  520  in the x axis direction. The rib  540  extends in the negative x axis direction beyond the end portion of the opening  520  on the negative x axis direction side. The rib  540  extends to the fastening portion  521  in which a screw hole  511  is formed. 
     A support portion  551  and a support portion  552  supporting the display apparatus are provided on the rib  540 . The display apparatus is in contact with and supported from below by the support portion  551  and the support portion  552 . 
     The rib  581  and the rib  582  extend to the rib  540 . Therefore, it is possible to restrict the localized focusing of stress in the loading surface  570 . 
       FIG.  11    is an exploded perspective view schematically showing another assembly example of the tripod base assembly. In this assembly example, a tripod base attaching member  1180  securing a tripod base  1170  is fastened together with the body-side mount  200  and a body  1100 . 
     The body-side mount  200  has the same structure as the body-side mount  200  described in relation to  FIGS.  1  to  10   . The body  1100  is formed of resin, in the same manner as the body  100 . The tripod base attaching member  1180  and the tripod base  1170  are formed of metal. The tripod base  1170  is a metal fitting for attaching a tripod. 
     The tripod base attaching member  1180  includes a securing section  1150  and a tripod base attaching portion  1140 . The tripod base attaching member  1180  has an overall L shape when cut in the xy plane. When the tripod base attaching member  1180  and the body  1100  are aligned, the tripod base attaching portion  1140  is positioned below the body  1100 . 
     Four female threads that are a female thread  1141 , a female thread  1142 , a female thread  1143 , and a female thread  1144  are formed in the tripod base attaching portion  1140 . Four through-holes including a hole  1172 , a hole  1173 , and a hole  1174  are formed in the tripod base  1170 . When the tripod base  1170  is aligned with the tripod base attaching portion  1140 , the four screw holes formed in the tripod base attaching portion  1140  are positionally fixed at the positions of the four holes formed in the tripod base  1170 , in a one-to-one manner. For example, the female thread  1142  is positionally fixed at the position of the hole  1172 , the female thread  1143  is positionally fixed at the position of the hole  1173 , and the female thread  1144  is positionally fixed at the position of the hole  1174 . In this state, the screw  1181  is inserted through the female thread  1141 , the screw  1182  is inserted through the female thread  1142 , the screw  1183  is inserted through the female thread  1143 , and the screw  1184  is inserted through the female thread  1144 , thereby fastening the tripod base  1170  to the tripod base attaching portion  1140 . 
     A female thread  1121 , a female thread  1122 , a female thread  1123 , a female thread  1124 , a female thread  1125 , and a female thread  1126  are formed in the securing section  1110  of the body  1100 . A hole  1151 , a hole  1152 , a hole  1153 , a hole  1154 , a hole  1155 , and a hole  1156  that are through-holes are formed in the securing section  1150  of the tripod base attaching member  1180 . 
     The body-side mount  200 , the securing section  1150 , and the securing section  1110  have ring shapes corresponding to each other. The body-side mount  200 , the securing section  1150 , and the securing section  1110 , when aligned with each other, each have six screw holes that are positionally fixed at the same positions in the xy plane. When in the aligned state, the body-side mount  200 , the securing section  1150 , and the securing section  1110  are fastened together by the screw  231 , the screw  232 , the screw  233 , the screw  234 , the screw  235 , and the screw  236 . In a state where the securing section  1150  is sandwiched between the body-side mount  200  and the body  1100 , the tripod base attaching member  1180  is secured to the body-side mount  200  and the body  1100 . 
     Specifically, when the hole  221 , the female thread  1121 , and the hole  1151  are in the aligned state, the screw  231  is inserted therethrough. When the hole  222 , the female thread  1122 , and the hole  1152  are in the aligned state, the screw  232  is inserted therethrough. When the hole  223 , the female thread  1123 , and the hole  1153  are in the aligned state, the screw  233  is inserted therethrough. When the hole  224 , the female thread  1124 , and the hole  1154  are in the aligned state, the screw  234  is inserted therethrough. When the hole  225 , the female thread  1125 , and the hole  1155  are in the aligned state, the screw  235  is inserted therethrough. When the hole  226 , the female thread  1126 , and the hole  1156  are in the aligned state, the screw  236  is inserted therethrough. In this way, the body  1100 , the tripod base attaching member  1180 , and the body-side mount  200  are fastened together at six points. 
     In this way, the tripod base attaching member  1180  is secured to the body-side mount  200 . In particular, the body-side mount  200 , the tripod base attaching member  1180 , and the body  1100  are secured at six points positioned in the same circle. Therefore, the stress placed on the tripod base  1170  from the tripod can be absorbed by the body-side mount  200  via the tripod base attaching member  1180 . 
     When the tripod base attaching member  1180  is secured between the body-side mount  200  and the securing section  1110 , such as in this assembly example, the front cover  300  may be secured near the securing section  1110 . Other structures including the front cover  300 , the top cover  400 , and the back cover  500  can adopt the same structure as described in relation to  FIGS.  1  to  10   . 
       FIG.  12    is an exploded perspective view schematically showing another assembly example of the tripod base assembly. In the present assembly example, components that are the same as components described in relation to  FIG.  11    are given the same reference numerals and descriptions thereof are omitted. 
     A hole  221 , a hole  222 , a hole  223 , a hole  224 , a hole  225 , a hole  226 , a hole  227 , and a hole  228  are formed in the body-side mount  1200 . The body-side mount  1200  differs from the body-side mount  200  by including the hole  227  and the hole  228 . The remaining structure of the body-side mount  1200  may be the same as the structure of the body-side mount  200 . The tripod base attaching member  1280  includes a securing section  1250  and a tripod base attaching portion  1140 . A hole  1254 , a female thread  1257 , and a female thread  1258  are formed in the securing section  1250  of the tripod base attaching member  1280 . 
     The screw  231  is inserted through the hole  221  and the female thread  1121 . The screw  232  is inserted through the hole  222  and the female thread  1122 . The screw  233  is inserted through the hole  223  and the female thread  1123 . The screw  234  is inserted through the hole  224 , the hole  1254 , and the female thread  1124 . The screw  235  is inserted through the hole  225  and the female thread  1125 . The screw  236  is inserted through the hole  226  and the female thread  1126 . 
     The screw  237  is inserted through the hole  227  and the female thread  1257 . The screw  238  is inserted through the hole  228  and the female thread  1258 . In this way, the body-side mount  1200  and the tripod base attaching member  1280  are fastened together by the screw  237  and the screw  238  as well. With this assembly example as well, the stress placed on the tripod base  1170  can be absorbed by the body-side mount  1200  via the tripod base attaching member  1280 . 
     In the imaging device  10  described above, the imaging unit  160  including an imaging element is used as an example of a light receiving unit that receives light passed through an interchangeable lens. The light receiving unit may be a focal point detection unit that includes a sensor for detecting a focal state from a subject. The sensor of the focal point detection unit may be a line sensor that detects a phase difference. The light receiving unit may be a finder unit. The finder unit may include a photometric unit that includes a photometric sensor for measuring the light amount from the subject. The finder unit may have a focus plate. 
     Among the imaging unit  160 , the finder unit, and the focal point detection unit that are examples of the light receiving unit, a light receiving unit that is a combination of one or more of these units may be secured to the body  100 . 
     For example, a single light receiving unit may be secured to the body  100 . Specifically, the imaging unit  160  alone may be secured to the body  100 . The finder unit alone may be secured to the body  100 . The focal point detection unit alone may be secured to the body  100 . In any of these cases, the imaging device  10  need not include a light receiving unit other than the light receiving unit secured to the body  100 . For example, the imaging device  10  may include just the imaging unit  160  as the light receiving unit, and the imaging unit  160  of the imaging device  10  may be secured to the body  100 . 
     Instead, two or more light receiving units may be secured to the body  100 . For example, just the imaging unit  160  and the finder unit may be secured to the body  100 . Just the imaging unit  160  and the focal point detection unit may be secured to the body  100 . Just the finder unit and the focal point detection unit may be secured to the body  100 . In any of these cases, the imaging device  10  need not include a light receiving unit other than the light receiving units secured to the body  100 . For example, the imaging device  10  may include just the imaging unit  160  and the finder unit as light receiving units, and have the imaging unit  160  and the finder unit of the imaging device  10  secured to the body  100 . The imaging device  10  may include just the imaging unit  160  and the focal point detection unit as the light receiving units, and have the imaging unit  160  and the focal point detection unit of the imaging device  10  secured to the body  100 . 
     The body  100  may have three light receiving units secured thereto. For example, the imaging unit  160 , the finder unit, and the focal point detection unit may be secured to the body  100 . In this case, the imaging device  10  need not include any light receiving units other than the light receiving units secured to the body  100 . For example, the imaging device  10  may include just the imaging unit  160 , the finder unit, and the focal point detection unit as the light receiving units, and the imaging unit  160 , the finder unit, and the focal point detection unit of the imaging device  10  may be secured to the body  100 . In this case, the imaging device  10  may include further light receiving units in addition to the imaging unit  160 , the finder unit, and the focal point detection unit. In other words, the imaging device  10  may further include one or more light receiving units that are not secured to the body  100 . 
     In the present embodiment, a camera body that does not include a lens apparatus is provided as an example of the structure of the imaging device. However, the imaging device may include a camera body and a lens unit. In addition to the single-lens reflex camera that is one example of an interchangeable lens camera, the imaging device can be a variety of types of cameras with interchangeable lenses. The imaging device is an example of a light receiving apparatus. The light receiving apparatus is not limited to an imaging device, and may be equipment other than an imaging device. 
     While the embodiments of the present invention have been described, the technical scope of the invention is not limited to the above described embodiments. It is apparent to persons skilled in the art that various alterations and improvements can be added to the above-described embodiments. It is also apparent from the scope of the claims that the embodiments added with such alterations or improvements can be included in the technical scope of the invention. 
     The operations, procedures, steps, and stages of each process performed by an apparatus, system, program, and method shown in the claims, embodiments, or diagrams can be performed in any order as long as the order is not indicated by “prior to,” “before,” or the like and as long as the output from a previous process is not used in a later process. Even if the process flow is described using phrases such as “first” or “next” in the claims, embodiments, or diagrams, it does not necessarily mean that the process must be performed in this order.