Abstract:
The imaging apparatus of the present invention includes a main body, first camera fixedly arranged on the main body, an opening-closing unit provided rotatably with respect to the main body via a first hinge unit, a second camera mounted on the opposite side of the opening-closing unit from the first hinge unit, and a second hinge unit for rotatably supporting the imaging direction of the second camera. A body surface of the second camera is uneven, and the rotation direction of the first hinge unit and the rotation direction of the second hinge unit are the same rotation direction at the time of starting shooting with the second camera.

Description:
BACKGROUND 
     1. Technical Field 
       [0001]    The present disclosure relates to an imaging unit and an imaging apparatus equipped with the imaging unit. 
       2. Description of the Related Art 
       [0002]    PTL1 discloses a mobile communication device equipped with a rotatable camera. Further various operations are demanded in an electronic apparatus equipped with a rotatable camera, such as this mobile communication device. 
       CITATION LIST 
     Patent Literature 
       [0000]    
       
         
           
             PTL1 Unexamined Japanese Patent Application No. 2003-51872 
           
         
       
     
       SUMMARY 
       [0004]    The present disclosure offers an imaging unit including a mechanism for tilting a lens forward and backward, and an imaging apparatus equipped with the imaging unit. 
         [0005]    To solve the above disadvantage, the imaging apparatus of the present disclosure includes a main body, first camera fixedly arranged on the main body, an opening-closing unit provided rotatably with respect to the main body via a first hinge unit, a second camera mounted on the opposite side of the opening-closing unit from the first hinge unit, and a second hinge unit for rotatably supporting the imaging direction of the second camera. A body surface of the second camera is uneven, and the rotation direction of the first hinge unit and the rotation direction of the second hinge unit are the same rotation direction at the time of starting shooting with the second camera. 
         [0006]    The present disclosure can offer a small imaging unit with good operability that can be rotated in two axial directions, and an imaging apparatus equipped with the imaging unit. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is a perspective view of an appearance of a digital video camera in accordance with an exemplary embodiment. 
           [0008]      FIG. 2  is a perspective view of the digital video camera in a state an openable unit is opened (non-use state). 
           [0009]      FIG. 3  is a perspective view of the digital video camera in the state the openable unit is opened (selfie state). 
           [0010]      FIG. 4  is a perspective view of the digital video camera in the state the openable unit is opened (confronting shooting state). 
           [0011]      FIG. 5  is a block diagram of an electrical configuration of the digital video camera. 
           [0012]      FIG. 6  is an exploded perspective view of the openable unit of the digital video camera. 
           [0013]      FIG. 7A  is a perspective view of a sub-camera and a switch unit. 
           [0014]      FIG. 7B  is a magnified perspective view of the switch unit shown in  FIG. 7A  (Part  7 B in  FIG. 7A ). 
           [0015]      FIG. 8  illustrates transition of the switch unit in line with the rotation of the sub-camera. 
           [0016]      FIG. 9  is a perspective view of the sub-camera. 
           [0017]      FIG. 10  is a perspective view of a camera unit of the sub-camera. 
           [0018]      FIG. 11  is a side view of the camera unit of the sub-camera in an upright state. 
           [0019]      FIG. 12  is a side view of the camera unit of the sub-camera in a forward tilt state. 
           [0020]      FIG. 13  is a side view of the camera unit of the sub-camera in a backward tilt state. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0021]    An exemplary embodiment is detailed below with reference to drawings. However, description in details more than necessary may be omitted. For example, detailed description of well-known subjects and duplicate description of practically the same configuration may be omitted. This is to avoid unnecessary redundancy in the description to facilitate understanding of a person having ordinary skill in the art. 
         [0022]    Inventors intend to provide attached drawings and the following description to enable a person having ordinary skill in the art fully understand the present disclosure. It is apparent that the description therefore does not limit in anyway the subject matters in the scope of claims. 
       Exemplary Embodiment 
     1. Outline of Digital Video Camera 
       [0023]      FIG. 1  is an appearance perspective view of digital video camera  100  in the exemplary embodiment. Digital video camera  100  is an example of an imaging apparatus. As shown in  FIG. 1 , digital video camera  100  includes camera body  200 , main camera  210  built in camera body  200 , and openable unit  230  openably coupled to camera body  200  via hinge unit  220 . 
         [0024]    Openable unit  230  is coupled to camera body  200  via hinge unit  220 , and is openably disposed on camera body  200 , centering around hinge unit  220 . Sub-camera  300  is provided at one end of openable unit  230  via a rotatable shaft mechanism. Sub-camera  300  is rotatable in forward and backward directions. In other words, digital video camera  100  includes main camera  210  and sub-camera  300 . Sub-camera  300  rotates relative to openable unit  230  to change the shooting direction. Openable unit  230  can open, close, and rotate relative to camera body  200  via hinge unit  220 . Accordingly, sub-camera  300  can change its shooting direction in various ways. Camera body  200  is an example of the imaging apparatus body. Sub-camera  300  is an example of the imaging unit. 
         [0025]      FIGS. 2, 3, and 4  are perspective views of digital video camera  100  in  FIG. 1  in a state openable unit  230  is opened.  FIG. 2  shows the state that sub-camera  300  is not used (mode 1).  FIGS. 3 and 4  show the selfie state (mode 2) and confronting shooting state (mode 3) of sub-camera  300 , respectively. 
         [0026]    As shown in  FIGS. 2, 3, and 4 , sub-camera  300  is installed in openable unit  230  via a rotatable mechanism that can be rotated about first axis  401  in forward and backward directions. Sub-camera  300  can be rotated clockwise from the state shown in  FIG. 2  to the state in  FIG. 3 , and then from the state in  FIG. 3  to the state in  FIG. 4  to change the shooting direction. Sub-camera  300  can also be rotated counterclockwise from the state in  FIG. 4  to the state in  FIG. 3 , and then from the state in  FIG. 3  to the state in  FIG. 2  to change the shooting direction. 
         [0027]    As shown in  FIG. 2 , openable unit  230  includes liquid crystal monitor unit  240 . Liquid crystal monitor unit  240  is disposed between sub-camera  300  and camera body  200 . Openable unit  230  can be kept opened relative to digital video camera  100  via hinge unit  220 , as shown in  FIG. 2 . In  FIG. 2 , an imaging surface (lens side) of sub-camera  300  faces inward of openable unit  230  (a direction of arrow A in  FIG. 2 ), which is the non-use state (mode 1). Next, as shown in  FIG. 3 , a photographer rotates sub-camera  300  from the non-use state in  FIG. 2  to a state (selfie state) that an imaging surface of sub-camera  300  faces the photographer (a direction of arrow B in  FIG. 3 ). This enables the photographer to shoot himself/herself using sub-camera  300 . In addition, liquid crystal monitor unit  240  can overlay an image captured by sub-camera  300  on an image captured by main camera  210  for display. The photographer can shoot while confirming how himself/herself is captured by looking at a through image displayed on liquid crystal monitor unit  240 . 
         [0028]    Next, as shown in  FIG. 4 , the photographer rotates sub-camera  300  from the selfie state in  FIG. 3  to a state that the imaging surface of sub-camera  300  faces the same direction (a direction of arrow C in  FIG. 4 ) as main camera  210  (confronting shooting state). The confronting shooting state, in which the imaging surface of sub-camera  300  faces the same direction as main camera  210 , does not only mean the case when the imaging surface of sub-camera  300  and the imaging surface of main camera  210  face completely the same direction. It means that sub-camera  300  captures an image in a direction the photographer is facing. The imaging surface of sub-camera  300  and the imaging surface of main camera  210  do not need to face completely the same direction. 
         [0029]    This enables the photographer to capture an image at a distance with main camera  210 , and capture an image nearby with sub-camera  300 , allowing various ways of shooting. In this case, liquid crystal monitor unit  240  can overlay an image captured by sub-camera  300  and an image captured by main camera  210  for display. 
         [0030]    Although not illustrated in the drawing, hinge unit  220  includes a shaft for opening and closing that is coupled to camera body  200  and a rotating shaft disposed orthogonal to this shaft for opening and closing. These shafts enable openable unit  230  to open and rotate relative to camera body  200 . 
         [0031]    Sub-camera  300  changes its shooting direction in various ways by rotating openable unit  230  relative to camera body  200  and rotating sub-camera  300  clockwise or counterclockwise relative to openable unit  230 . For example, in the selfie mode shown in  FIG. 3 , sub-camera  300  can capture downward or upward from the shooting direction shown in  FIG. 3  by rotating openable unit  230 . 
         [0032]    As shown in  FIG. 2  and  FIG. 4 , sub-camera  300  also includes lens tilt mechanism  400  to change the shooting direction upward or downward. Sub-camera  300  can thus also change the shooting direction without rotating openable unit  230 , i.e., in the state the direction of liquid crystal monitor unit  240  is fixed. Lens tilt mechanism  400  is described later. 
       2. Block Circuit Configuration of Digital Video Camera 
       [0033]      FIG. 5  is a block diagram illustrating an electrical configuration of digital video camera  100 . As shown in  FIG. 5 , openable unit  230  of digital video camera  100  includes liquid crystal monitor unit  240 , sub-camera  300 , and switch unit  250  for detecting a rotating position of sub-camera  300 . Camera body  200  includes controller  260  that receives information on the rotating position of sub-camera  300  sent from switch unit  250 . Information on the rotating position of sub-camera  300  sent from switch unit  250  and image signals from an imaging element of sub-camera  300  are sent to controller  260  of camera body  200  via liquid crystal monitor unit  240 . Although not illustrated, camera body  200  includes an optical system of lens group, an imaging element such as COMS image sensor, image processor, memory card slot, and control panel such as a shooting button, in addition to controller  260 . 
         [0034]    Controller  260  is a control means for controlling the entire digital video camera  100 , and is typically a microcomputer. Controller  260  may be configured only by hardware, or by a combination of hardware and software. Controller  260  outputs to liquid crystal monitor unit  240  images captured by main camera  210  and sub-camera  300 , and image signals for displaying a range of menu screens for various settings of digital video camera  100 . 
       3. Configuration of Sub-Camera 
       [0035]    Next, the configuration of sub-camera  300  is described.  FIG. 6  is an exploded perspective view of openable unit  230 . As shown in  FIG. 6 , openable unit  230  includes liquid crystal monitor unit  240 , upper case  230   a , lower case  230   b , sub-camera  300 , sub-camera hinge unit  310 , and switch unit  250  having flexible printed wiring board  350 . 
         [0036]    Liquid crystal monitor unit  240  includes electronic control board  240   b  on the side of upper case  230   a  that is the back of a display. An electrical circuit for controlling liquid crystal monitor unit  240 , a connector to which flexible printed wiring board  350  for taking out the electric signal from sub-camera  300  is connected, and a connector for electrically connecting to controller  260  of camera body  200  are disposed on this electronic control board  240   b . Electronic control board  240   b  is electrically connected to controller  260  of camera body  200  to send and receive image signals and control signals to and from controller  260 . 
         [0037]    Upper case  230   a  and lower case  230   b  are integrally coupled to form a casing of openable unit  230 . Upper case  230   a  and lower case  230   b  house liquid crystal monitor unit  240  when they are integrally coupled. Sub-camera  300  is assembled with upper case  230   a  and lower case  230   b  via sub-camera hinge unit  310  and switch unit  250 . Sub-camera hinge unit  310  configures a rotatable shaft mechanism to hold sub-camera such that it can be rotated about first axis  401  in forward and backward directions. Sub-camera  300  is also electrically connected to electronic control board  240   b  disposed on liquid crystal monitor unit  240  via flexible printed wiring board  350 . This enables to send electric signals corresponding to the rotating direction (shooting direction) of sub-camera  300  to controller  260  according to switchover of the rotating position of sub-camera  300 . 
         [0038]      FIG. 7A  is a perspective view of sub-camera  300 , which is an imaging unit.  FIG. 7B  is a magnified perspective view of switch unit  250  of sub-camera  300 . As shown in  FIG. 7A , sub-camera  300  includes cylindrical housing  390  and lens tilt mechanism  400 . Sub-camera hinge unit  310  and switch unit  250  rotatably support sub-camera  300  around first axis  401  relative to openable unit  230 . 
         [0039]    Sub-camera hinge unit  310  is provided on an upper end of sub-camera  300 , and includes fitting  311 , rotating end  312 , and rotating shaft  313 . Fitting  311  made of a metal sheet is fixed onto upper case  230   a  and lower case  230   b  of openable unit  230  typically with screw. Fitting  311  has a screw hole to attach sub-camera hinge unit  310  to openable unit  230  typically with screw. Rotating end  312  restricts a rotation range when sub-camera  300  rotates about rotating shaft  313 . Rotating shaft  313  is the center of rotation of sub-camera  300  rotatably held relative to openable unit  230 , and configures one end of first axis  401 . Sub-camera hinge unit  310  is configured to restrict the rotation range of sub-camera  300  to 270 degrees. More specifically, in sub-camera hinge unit  310 , when sub-camera  300  is rotated about rotating shaft  313  (first axis  401 ) clockwise or counterclockwise, rotating end  312  contacts a metal sheet of fitting  311  to restrict the rotation exceeding the rotation range. 
         [0040]    Lens tilt mechanism  400  includes camera unit  380  and operating member  420 , as shown in  FIG. 7A . Camera unit  380  is disposed in the middle of housing  390 , and includes lens holder  410 , a lens group of optical system (e.g., lens  381 ), and an imaging element, such as CMOS image sensor. Camera unit  380  is electrically connected to flexible printed wiring board  350 . Image signals captured by camera unit  380  are sent to controller  260  in camera body  200  via flexible printed wiring board  350 . 
         [0041]    Switch unit  250  detects the rotating position of sub-camera  300 , and is configured to send electric signals corresponding to each of the shooting states of sub-camera to controller  260  via flexible printed wiring board  350 . The shooting states include the non-use state (mode 1) in the direction of arrow A in  FIG. 2 , the selfie state (mode 2) in the direction of arrow B in  FIG. 3 , and the confronting shooting state (mode 3) in the direction of arrow C in  FIG. 4 . 
         [0042]    As shown in  FIG. 7B , switch unit  250  is disposed on the lower end of sub-camera  300 . Switch unit  250  includes switch body  320 , flexible printed wiring board  350 , rotating piece  370 , and fixing plate  330  made of a metal sheet holding these components. 
         [0043]    Switch body  320  has a function as a holder for holding switch lever  340 , is electrically connected to flexible printed wiring board  350 , and is fixed onto fixing plate  330 . Switch lever  340  is configured to indicate the three modes when switch lever  340  tilts from a center reference position to a right or left position when the center is set as the reference position. Switch body  320  includes a biasing means inside to urge switch lever  340 . The biasing means urges switch lever  340  to self-recover to the reference position even when switch lever  340  displaces from the center reference position to a tilt position to the left or right. Therefore, switch lever  340  self-recovers to the center reference position by the biasing force of the biasing means when switch lever  340  is released from a state tilted to the left or right relative to switch body  320 . 
         [0044]    Rotating piece  370  is disposed on fixing plate  330  in a rotatably supported state, and rotates in line with the rotation of sub-camera  300 . More specifically, sub-camera  300  is rotatably supported by fitting  311  on the side of sub-camera hinge unit  310 , and rotatably supported by fixing plate  330  on the side of switch unit  250 . Rotating cam  371  of rotating piece  370  includes rotating cam groove  373 , which is a notch, and slope  372  gradually inclined from an outer peripheral face of rotating cam  371  to rotating cam groove  373 . Rotating cam  371  has a cam structure (rotor) configured around first axis  401 , which is the rotating axis of sub-camera  300 , and has a portion thicker than main shaft  360  of rotating piece  370  and rotating cam groove  373  created by partially notching the thick portion. Slope  372  with a specified inclination is formed on a portion connecting (boundary portion) the portion thicker than main shaft  360  and rotating cam groove  373 . 
         [0045]    The reference position of switch lever  340  does not need to be limited to the center. The reference position may be a position tilted from the center position to either left or right, and the three modes may be indicated by this position, the center position, and a position opposite to the reference position. It is apparent that switch lever  340  is not limited to a structure of indicating the three modes. It may be configured to indicate four or five modes. Switch lever  340  is thus configured to at least indicate three modes, i.e., first mode, second, mode, and third mode. 
         [0046]    Switch lever  340  changes its detection state based on a tilt angle in a direction tilted relative to switch body  320 . As sub-camera  300  rotates about the rotating axis, slopes  372  formed on both ends of rotating cam groove  373  of rotating cam  371  rotate while making contact with switch lever  340 . Slope  372  is provided at a predetermined tilt angle so that switch lever  340  can detect transition between mode 1 and mode 2, and transition between mode 2 and mode 3 in line with the rotation of rotating cam  371 . If the imaging surface of sub-camera  300  (the side of lens  381  of camera unit  380 ) is configured to face the direction of photographer when switch lever  340  comes to the position facing rotating cam groove  373 , the position of rotating cam groove  373  is preferably designed to avoid capturing a part of camera body  200  (rear part) in the shooting range of sub-camera  300 . 
         [0047]    By setting the height of rotating cam  37  in the rotating direction higher than that of switch lever  340 , switch lever  340  reliably contacts rotating cam  371 . 
       4. Operation of the Detection Switch in Line with the Rotation of Sub-Camera) 
       [0048]      FIG. 8  illustrates transition of switch unit  250  in line with the rotation of sub-camera  300 . 
         [0049]    Mode 1 in  FIG. 8  shows the non-use state of sub-camera  300 . As shown in  FIG. 2 , the non-use state (mode 1) is the state that the imaging surface of sub-camera  300  faces inward of openable unit  230  (a direction of arrow A in  FIG. 8  and  FIG. 2 ). Here, as shown in mode 1 in  FIG. 8 , switch lever  340  is tilted and biased in one direction relative to switch body  320  by making contact with rotating cam  371  of rotating piece  370 . Switch body  320  sends a signal indicating that sub-camera  300  is in the non-use state (mode 1) to controller  260  in camera body  200  via flexible printed wiring board  350 . 
         [0050]    Mode 2 in  FIG. 8  shows the state that sub-camera  300  is rotated from the non-use state to the selfie state. The selfie state (mode 2) is the state that sub-camera  300  is rotated for a predetermined angle from mode 1 in  FIG. 8  and the imaging surface of sub-camera  300  faces a direction of photographer (a direction of arrow B in  FIG. 8  and  FIG. 3 ), as shown in  FIG. 3 . More specifically, when sub-camera  300  is in the selfie state, a positional relationship is such that rotating cam groove  373  faces switch lever  340 , as shown in mode 2 in  FIG. 8 . Here, switch lever  340  is released from the state urged in one direction by rotating cam  371  and self-recovers to the center reference position. Switch body  320  sends a signal indicating that sub-camera  300  is in the selfie state to controller  260  in camera body  200  via flexible printed wiring board  350 . 
         [0051]    Mode 3 in  FIG. 8  is the state that sub-camera  300  rotates from the selfie state to the confronting shooting state. The confronting shooting state (mode 3) is the state that the imaging surface of sub-camera  300  is further rotated from mode 2 in  FIG. 8  to face substantially the same direction as main camera  210  (a direction of arrow C in  FIG. 8  and  FIG. 4 ). Here, as shown in mode 3 in  FIG. 8 , switch lever  340  contacts slope  372  formed on rotating cam  371  of rotating piece  370 , and is urged to tilt in a direction different from mode 1 in  FIG. 8  by being pushed further by rotating cam  371 . Here, switch body  320  sends a signal indicating that sub-camera  300  is in the confronting shooting state to controller  260  of camera body  200  via flexible printed wiring board  350 . 
         [0052]    As described above, digital video camera  100  can detect whether the rotating position of sub-camera  300  is in the non-use state (mode 1 in  FIG. 2  and  FIG. 8 ), the selfie state (mode 2 in  FIG. 3  and  FIG. 8 ), or the confronting shooting state (mode 3 in  FIG. 4  and  FIG. 8 ) by using switch unit  250 . 
         [0053]    As described above, switch unit  250  includes switch body  320  having switch lever  340  that is a lever unit configured to self-recover to the reference position, and rotating piece  370  with which switch lever  340  makes contact. Rotating piece  370  has rotating cam  371  with rotating cam groove  373  that is a notch on a part of rotating cam  371 . As rotating piece  370  rotates about the axis in one direction, rotating piece  370  transits to mode 1 in which switch lever  340  does not face rotating cam groove  373 , mode 2 in which switch lever  340  faces rotating cam groove  373  in the reference position, and mode 3 in which switch lever  340  does not face rotating cam groove  373 . Switch body  320 , which is a detector, detects whether rotating piece  370  is in mode 1, mode 2, or mode 3. Controller  260  then determines the shooting direction of sub-camera  300  based on a signal from switch body  320 . 
         [0054]    Accordingly, in switch unit  250 , the direction of switch lever  340  changes according to the shooting direction of sub-camera  300 : a direction of arrow A in  FIG. 2 , a direction of arrow B in  FIG. 3 , or a direction of arrow C in  FIG. 4 . Switch body  320 , which is the detector in switch unit  250 , can send a signal corresponding to the direction of switch lever  340  to controller  260 . 
         [0055]    Next is described lens tilt mechanism  400  for changing the shooting direction of camera unit  380  with reference to  FIGS. 9 to 13 . As shown in  FIG. 9 , sub-camera  300  can rotate about first axis  401  in forward and backward directions in the state lens tilt mechanism  400  for tilting lens  381  forward and backward is housed in housing  390 . Lens tilt mechanism  400 , as shown in  FIG. 9  and  FIG. 10 , includes camera unit  380  and operating member  420 . Camera unit  380  includes lens  381  and lens holder  410  housing lens  381 . In the exemplary embodiment, as shown in  FIG. 9 , first axis  401 , second axis  402 , and third axis  403  are orthogonal to each other. Camera unit  380  is rotatable about second axis  402  in forward and backward directions, and operating member  420  is rotatable about third axis  403  in forward and backward directions. 
         [0056]    Lens holder  410  holds the optical system, such as lens  381 , on its surface, and has first gear  411  extending around second axis  402 . Lens holder  410  is supported by housing  390  such that lens holder  410  is rotatable about second axis  402  in forward and backward directions. First gear  411  is disposed on a rim of a plane (side wall  412 ) with second axis  402  of lens holder  410  as a normal, on the side of operating member  420 . First gear  411  is configured with four gear teeth in  FIG. 10 . However, the structure is not limited to four gear teeth. Any structure with at least gear teeth on the back side of lens holder  410  is acceptable. In the exemplary embodiment, lens holder  410  is rotatable about second axis  402  in a range of 22 degrees upward and 22 degrees downward relative to the horizontal direction. 
         [0057]    Operating member  420  is disposed on the back side of lens holder  410 , and supported by housing  390  such that operating member is rotatable about third axis  403  in forward and backward directions. Operating member  420  is a disk member, and second gear  421  that engages with first gear  411  is disposed upright on the side of lens holder  410  around third axis  403 . When operating member  420  rotates about third axis  403 , second gear  421  engages with first gear  411  to rotate first gear  411  about second axis  402 . Lens holder  410  (camera unit  380 ) then rotates about second axis  402 . Second gear  421  is configured with three gear teeth in  FIG. 10  but not limited to this structure. Operating member  420  includes operating knob  422  and gear  423 . 
         [0058]    Operating knob  422  is provided near second gear  421  and is bent and extended toward lens holder  410 . Gear  423  for antislipping is provided at a rim of the disk member of operating member  420 . The photographer can easily rotate operating member  420  by operating operating knob  422  and gear  423  for antislipping typically with fingers. Since operating knob  422  is bent and extended toward lens holder  410 , operating knob  422  does not protrude outside of cylindrical space  231  even if lens holder  410  is rotated about second axis  402  by operating member  420 . Sub-camera  300  can thus smoothly rotate about first axis  401  in cylindrical space  231 . Operating knob  422  is formed extending along the outer peripheral face of cylindrical space  231  so that operating knob  422  can be operated relative to camera unit  380  regardless of the rotating position of sub-camera  300  rotating about first axis  401 . In other words, operating knob  422  is formed in a circumferential direction of first axis  401 . In addition, as shown in  FIG. 9 , three protrusions  385  and splined surface  386  are formed on sub-camera  300  for antislipping. Therefore, the photographer can easily rotate sub-camera  300  about first axis  401  by operating three protrusions  385  and splined surface  386  for antislipping typically with fingers. 
         [0059]    First axis  401 , second axis  402 , and third axis  403  do not need to be strictly orthogonal to each other. As long as the plane with first axis  401  as a normal, the plane with second axis  402  as a normal, and the plane with third axis  403  as a normal cross each other, any structure is acceptable. As an example, these three planes perpendicularly cross each other in the exemplary embodiment. 
         [0060]    Next is described the operation of lens tilt mechanism  400  with reference to  FIGS. 11 to 13 .  FIG. 11 ,  FIG. 12 , and  FIG. 13  show the state of lens tilt mechanism  400  in the upright position, forward tilt position, and backward tilt position of lens holder  410 , respectively. 
         [0061]    Camera unit  380  is supported such that it is rotatable about second axis  402  in forward and backward directions relative to housing  390  so that camera unit  380  can be tilted in a predetermined angular range. The predetermined angular range is a range between the forward tilt position II (see  FIG. 12 ) in which camera unit  380  is tilted forward relative to upright position I and backward tilt position III (see  FIG. 13 ) in which camera unit  380  is tilted backward relative to upright position I (see  FIG. 11 ) with reference to upright position I where optical axis O of lens  381  of camera unit  380  coincides with third axis  403 . 
         [0062]    Here, cylindrical space  231  is a cylindrical space formed as an operation locus of housing  390  rotating about first axis  401 . Housing  390  includes forward tilt limiter (forward tilt stopper)  391  and backward tilt limiter (backward tilt stopper)  392  for restricting a position of forward tilting operation (forward tilt position II) in forward rotation and a position of backward tilting operation in backward rotation (backward tilt position III) of lens holder  410  so that lens holder  410  does not protrude outside cylindrical space  231  when camera unit  380  rotates about second axis  402 . More specifically, as shown in  FIG. 12 , lens holder  410  touches forward tilt limiter  391  when camera unit  380  tilts forward, and thus camera unit  380  is restricted at forward tilt position II. In the same way, as shown in  FIG. 13 , lens holder  410  touches backward tilt limiter  392  when camera unit  380  tilts backward, and thus camera unit  380  is restricted at backward tilt position III. 
         [0063]    The restriction of the tilting operation of camera unit  380  at forward tilt position II and backward tilt position III prevents protrusion of camera unit  380  outside cylindrical space  231 , and ensures the smooth rotation of sub-camera  300  around first axis  401  inside cylindrical space  231 . In addition, the rotation of operating member  420  may be restricted to limit a rotation angle, so as to restrict the position of tilting operation of camera unit  380 . For example, operating knob  422  of operating member  420  may contact a restricting member provided on housing  390  for restricting the rotation of operating member  420 . Or, a separate protrusion may be provided on operating member  420  to restrict its rotation. 
         [0064]    Accordingly, by the use of lens tilt mechanism  400 , camera unit  380  rotates about second axis  402  among forward tilt position II, upright position I, and backward tilt position III as the photographer rotates operating member  420  about third axis  403 . As a result, camera unit  380  of sub-camera  300  can be rotated about second axis  402  in forward and backward directions regardless of an opening angle of openable unit  230 . Still more, camera unit  380  can be tilted while being rotated about second axis  402  in forward and backward directions inside same cylindrical space  231 , in addition to the rotation of entire sub-camera  300  about first axis  401  in forward and backward directions in cylindrical space  231  formed in one end of openable unit  230 . 
         [0065]    Accordingly, the exemplary embodiment offers small sub-camera  300  with good operability and digital video camera  100  including sub-camera  300  that is rotatable forward and backward in two directions independently: first axis  401  and second axis  402 . 
         [0066]    In other words, in camera unit  380  that is rotatable about first axis  401  in forward and backward directions in cylindrical space  231 , lens tilt mechanism  400  in the exemplary embodiment enables camera unit  280  to rotate and tilt about second axis  402  in forward and backward directions via engagement of second gear  421  and first gear  411  by rotating operating member  420  about third axis  403  in forward and backward directions inside this cylindrical space. Accordingly, lens tilt mechanism  400  has a simple and compact structure, and sub-camera  300  can rotate forward and backward about first axis  401  and also rotate forward and backward about second axis  402  (the forward and backward tilting operation of camera unit  380  by lens tilt mechanism  400 ) at the same time inside cylindrical space  231  formed on one end of openable unit  230 . 
         [0067]    First gear  411  is always positioned on the side of operating member of lens holder  410  during the forward and backward rotation of lens holder  410  about second axis  402 , and thus first gear  411  is not exposed on the surface, also achieving good appearance design. 
       5. Other Exemplary Embodiments 
       [0068]    The above exemplary embodiment is described as an example of technology disclosed in the present disclosure. However, technology in the present disclosure is not limited in any way by the exemplary embodiment. Other exemplary embodiments including any change, replacement, addition, or omission to the exemplary embodiment are therefore intended to be embraced therein. 
         [0069]    For example, the above exemplary embodiment has a structure that sub-camera  300  transits from the non-use state (mode 1) to the selfie state (mode 2), and then from the selfie state to the confronting shooting state (mode 3), and sub-camera  300  faces the photographer when switch lever  340  comes to the position facing rotating cam groove  373 . However, sub-camera  300  may transit from the non-use state to the confronting shooting state, and then from the confronting shooting state to the selfie state, and sub-camera  300  may be set to the confronting shooting state when switch lever  340  comes to the position facing rotating cam groove  373 . In other words, switch lever  340  may come to the position facing rotating cam groove  373  at the center position when sub-camera  300  transits to at least three modes. 
         [0070]    Still more, the shape of rotating cam groove  373  is not limited to the shape in the above exemplary embodiment. For example, rotating cam groove  373  may be formed by an arc notch. Still more, the state may be switched when switch lever  340  faces slope  372 . 
         [0071]    Still more, the rotation limiter provided in sub-camera hinge unit  310  restricts the rotation of sub-camera  300  to within a 270-degree rotation range in the exemplary embodiment. However, the present disclosure is not limited to this range. More specifically, sub-camera  300  may be rotated beyond the 270-degree rotation range without providing the rotation limiter in sub-camera hinge unit  310 . 
         [0072]    Still more, sub-camera  300 , which is an imaging unit, in the exemplary embodiment is rotatably fixed in cylindrical space  231  formed in one end of openable unit  230 . However, sub-camera  300  may be detachably disposed relative to openable unit  230 . In this case, sub-camera  300  may have wired connection with openable unit  230  or wireless connection with controller  260  of camera body  200  for sending image signals. 
         [0073]    To give an exemplary embodiment of the disclosed technology, attached drawings and components described herein may include those not essential for solving the disadvantage, in addition to components essential for solving the disadvantage. It is therefore apparent that these non-essential components shall not be noted as essential just because they are included in attached drawings or description. 
         [0074]    The exemplary embodiment described herein are therefore illustrative. All modifications including changes, replacements, additions, and omissions, which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. 
       INDUSTRIAL APPLICABILITY 
       [0075]    The present disclosure is applicable to rotatable cameras, digital video cameras equipped with the camera, and imaging devices, such as other wearable cameras and on-vehicle cameras.