Patent Publication Number: US-2022236624-A1

Title: Imaging device

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to an imaging device, and more particularly, to an imaging device capable of adjusting an imaging direction through an electromotion. 
     Description of the Related Art 
     In recent years, the demand for imaging devices capable of a broad imaging range has increased. Of such imaging devices, there are imaging devices in which a plurality of imaging units can be shifted and moved in a circumferential direction centering on a central axis of a casing. Further, there are imaging devices on which illuminations are mounted to capture clear videos in the darkness. The publication of US Patent Application No. 2020/0174343 discloses a configuration in which an auxiliary light unit including an illumination can be assembled in a camera body including a plurality of imaging units. 
     There is also an imaging device in which an illumination is disposed in the same space as an imaging unit. When an illumination is disposed in the same space as an imaging unit, it is necessary to provide a light-shielding member between the imaging unit and the illumination in order to avoid a video of reflected light of the illumination in a transparent protective cover. As a technology useful for such a light-shielding member, U.S. Pat. No. 10,612,663 discloses a gasket that shields light so that reflected light from a protective cover does not arrive at a lens barrel in an imaging device including a plurality of imaging units. 
     In the configuration disclosed in US Patent Application No. 2020/0174343, however, the size of a casing may increase since an illumination is disposed in a space separate from the imaging units. On the other hand, in the configuration disclosed in U.S. Pat. No. 10,612,663, an increase in the size can be inhibited. However, when motorization is implemented to remotely adjust an imaging direction of an imaging unit, friction between a protective shield and a gasket may be a large load. As a method of solving these, a method of retracting a light-shielding member through an electromotion when an angle of field of an imaging unit is adjusted is conceivable. However, when an actuator is separately mounted to retract the light-shielding member, cost may increase and the size of the body may increase. 
     SUMMARY OF THE INVENTION 
     An embodiment of the present invention provides a technology capable of retracting a light-shielding member in a simple configuration while inhibiting an increase in the size of an imaging device capable of changing an imaging direction. 
     According to an embodiment of the present invention, an imaging device includes: at least one imaging unit configured to be rotatable and movable in a circumferential direction with a driving mechanism; an illumination; a cover configured to cover the imaging unit and the illumination; and a light-shielding member of which at least a part is disposed between the imaging unit and the illumination and is disposed in contact with the cover. The light-shielding member is able to be retracted away from the cover through driving of the driving mechanism. 
     Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded perspective view illustrating an imaging device according to an embodiment. 
         FIG. 2  is an exploded perspective view illustrating a top case unit. 
         FIG. 3  is an exploded perspective view illustrating a bottom case unit. 
         FIG. 4  is an exploded perspective view illustrating an imaging unit. 
         FIG. 5  is a sectional view illustrating the imaging unit. 
         FIGS. 6A and 6B  are sectional views illustrating the periphery of the imaging unit to describe a method of locking a retraction mechanism of a light-shielding unit. 
         FIGS. 7A and 7B  are sectional views illustrating the periphery of the imaging unit to describe a method of unlocking the retraction mechanism of the light-shielding unit. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the appended drawings. Here, the dimensions, materials, and relative positions or the like of constituent elements to be described in the following embodiments are arbitrary and can be changed in accordance with a configuration and various conditions of a device to which an embodiment of the present invention is applied. Cables or components which are not directly involved in the embodiment of the present invention will not be described and are not illustrated. Further, to facilitate description, shapes or the like of components will be described in a simplified form in some cases. 
     Embodiment 
     In an embodiment, an example of an imaging device to which the present invention is applied will be described.  FIG. 1  is an exploded perspective view illustrating an imaging device  1  according to an embodiment. The imaging device  1  includes a top case unit  3  and a bottom case unit  4 . The top case unit  3  is fixed to the bottom case unit  4  by fastening screws  2 . A gasket (not illustrated) is disposed between the top case unit  3  and the bottom case unit  4  to inhibit intrusion of rain or dust into the imaging device  1 . 
       FIG. 2  is an exploded perspective view illustrating the top case unit  3 . The top case unit  3  includes a top case  5 , a protective cover  6 , and a protective cover holder  7 . The protective cover  6  is a transparent member of polycarbonate or the like and protects a plurality of imaging units  9  to be described below against rain, dust, or shocks from outside. The protective cover  6  and a flange  6   a  are interposed between the top case  5  and the protective cover holder  7 . The gasket (not illustrated) is disposed between the top case  5  and the protective cover  6  to inhibit intrusion of rain or dust into the imaging device  1 . 
       FIG. 3  is an exploded perspective view illustrating the bottom case unit  4 . The bottom case unit  4  includes an imaging unit holder  8 , the plurality of imaging units  9 , a shift base  10 , a bottom case  11 , and a plurality of infrared illumination units  12 . In the embodiment, the imaging device  1  includes, for example, three imaging units  9  and three infrared illumination units  12 , but it may include one or more imaging units  9  and one or more infrared illumination units  12 . As the number of imaging units  9  included in the imaging device  1  is larger, a broader range can be imaged at a time. 
     The imaging unit  9  includes a lens barrel  902  (imaging unit) that includes an image sensor and a lens group (neither of which is illustrated) and a protrusion  914  is interposed between the imaging unit holder  8  and the shift base  10 . The imaging unit  9  holds the lens barrel  902  tilting rotatably and can be shifted and moved on the shift base  10 . The titling mentioned here is rotation in a vertical direction and a circumference of the shaft perpendicular to an optical shaft of the lens barrel  902  and the shifting is movement in a circumferential direction about a central axis A of the imaging device  1 . 
     The infrared illumination unit  12  includes an infrared illumination  12   a  and is fixed to the imaging unit  9 , as will be described below in detail. 
     The shift base  10  includes a spur gear  10   a  and is fixed to the bottom case  11 . Between the shift base  10  and the bottom case  11 , a printed substrate (not illustrated) on which a video engine processing an output signal of the image sensor or a network engine performing network communication is mounted is disposed. 
       FIG. 4  is an exploded perspective view illustrating the imaging unit  9 .  FIG. 5  is a sectional view illustrating the imaging unit  9 . To facilitate description, the infrared illumination unit  12  fixed to the imaging unit  9  is illustrated in  FIG. 4 . The lens barrel  902  is fixed to a lens barrel holder  904 . 
     The lens barrel holder  904  including a helical gear  904   a  for tilting, a light-shielding unit  904   b  for initial alignment of tilting by a photo-interrupter  908  to be described below, and a pressing unit  904   c  with a protrusion shape is held to be tilted with respect to a tilting base  907 . A rear cover  905  including a front cover  903  and a pressing unit  905   a  with a protrusion shape is fixed to the lens barrel holder  904 . That is, the lens barrel holder  904 , the front cover  903 , and the rear cover  905  serve as a holding unit that holds the lens barrel  902 . 
     The above-described infrared illumination unit  12  is disposed in a space covered by the protective cover  6 . The infrared illumination unit  12  is tilted to interlock with tilting of the corresponding lens barrel  902 . The infrared illumination unit  12  is preferably fixed to the lens barrel holder  904 , for example, so that a radiation direction of the infrared illumination  12   a  substantially matches an imaging direction of the lens barrel  902 . Thus, the radiation direction of the infrared illumination  12   a  can substantially match the imaging direction of the lens barrel  902  regardless of a shift position and a tilting angle of the lens barrel  902 , and thus it is possible to implement inhibition of radiation unevenness and a reduction in power consumption. For example, a driving mechanism for tilting of the lens barrel  902  can be used for tilting of the infrared illumination  12   a  without fixing the infrared illumination unit  12  to the lens barrel holder  904  to interlock with tilting of the lens barrel  902  and the infrared illumination  12   a.  A driving mechanism for tilting different from the lens barrel  902  can also be used to interlock with tilting of the lens barrel  902  and the infrared illumination  12   a  by performing control. 
     The tilting base  907  includes a first tilting base  9071  and a second tilting base  9072 , and a lock member  909  is disposed between the first tilting base  9071  and the second tilting base  9072 . 
     In the first tilting base  9071 , a tilting motor unit  906  and the photo-interrupter  908  are disposed. 
     The tilting motor unit  906  includes a stepping motor  906   a  and a worm  906   b.  The worm  906   b  is pressed and fitted in an output shaft of the stepping motor  906   a.  The worm  906   b  engages with the helical gear  904   a  of the lens barrel holder  904 , and thus the lens barrel  902  can be tilted along with the lens barrel holder  904  using the stepping motor  906   a  as a power source. That is, the tilting motor unit  906  is a driving mechanism for tilting. 
     The photo-interrupter  908  is mounted on a flexible substrate (not illustrated) by soldering and is started by conduction. Initial alignment of tilting is performed by detecting a position at which the light-shielding unit  904   b  of the lens barrel holder  904  comes between a light-emitting portion and a light-receiving portion of the photo-interrupter  908 . That is, the photo-interrupter  908  is a detector that detects a tilting angle. After the initial alignment of tilting, a tilting angle is ascertained based on the number of driving pulses of the stepping motor  906   a.    
     A shift motor unit  912  and a shift gear unit  913  are disposed in the second tilting base  9072 . The shift motor unit  912  includes a stepping motor  912   a  and a worm  912   b.  The shift gear unit  913  includes a helical gear  913   a  and a spur gear  913   b.  The worm  912   b  is pressed and fitted in an output shaft of the stepping motor  912   a.  The worm  912   b  engages with the helical gear  913   a  and the spur gear  913   b  engages with the spur gear  10   a  of the above-described shift base  10 , and thus the lens barrel  902  can be shifted along with the second tilting base  9072  using the stepping motor  912   a  as a power source. 
     The second tilting base  9072  includes four guide poles  9072   a  and one guide groove  9072   b.  A light-shielding unit urging spring  910  is disposed around each guide pole  9072   a.  A light-shielding unit  901  provided in order to shield light of the infrared illumination  12   a  is loosely fitted on the guide pole  9072   a.  In the embodiment, the light-shielding unit  901  is disposed to cover the lens barrel  902 , for example. The top case unit  3  is mounted on the bottom case unit  4 , the light-shielding unit urging spring  910  is compressed so that the light-shielding unit  901  is urged toward the protective cover  6  along the guide pole  9072   a.  A protective cover adhesion surface  901   a  formed of an elastic member such as rubber is adhered to the inner surface of the protective cover  6 . Thus, reflected light of the infrared illumination  12   a  in the protective cover  6  does not arrive at the lens barrel  902 , and thus the light is shielded. An elastic member such as rubber of which the protective cover adhesion surface  901   a  is molded can be integrated with a frame  901   d  formed of a resin. 
     The lock member  909  is disposed in the guide groove  9072   b,  and the lock member  909  is sandwiched between the first tilting base  9071  and the second tilting base  9072 . A lock member urging spring  911  is compressed and disposed between the second tilting base  9072  and the lock member  909 . The lock member  909  is urged backward along the guide groove  9072   b  by the lock member urging spring  911  to be held at a position at which lock member  909  comes into contact with the first tilting base  9071 . 
       FIGS. 6A and 6B  are sectional views illustrating the periphery of the imaging unit  9  to describe a method of locking a retraction mechanism of a light-shielding unit  901 .  FIGS. 7A and 7B  are sectional views illustrating the periphery of the imaging unit  9  to describe a method of unlocking the retraction mechanism of the light-shielding unit  901 . Hereinafter, up, down, front, and rear directions, positive and negative directions of tilting, and a value of a tilting angle are as shown in  FIGS. 6A, 6B, 7A, and 7B . That is, an installation surface direction is a downward direction, a direction opposite to an installation surface is an upward direction, an imaging direction in which a tilting angle is 0 degrees is a forward direction, and a direction opposite to the imaging direction (the forward direction) is a rearward direction using the imaging unit  9  as a reference. 
     In the embodiment, when the imaging unit  9  performs imaging, a tilting angle which can be set in adjustment of an angle of field as a tilting angle at which no vignetting occurs due to the top case  5  or the light-shielding unit  901  is assumed to be in a range from +10 degrees to +120 degrees, for example. A tilting range in which rotation can be performed in adjustment of an angle of field to retract the light-shielding unit  901  is assumed to be in a range from −20 degrees to +125 degrees, for example. The tilting angle can be calculated from the number of driving pulses of the stepping motor  906   a  after the tilting initial alignment by the photo-interrupter  908 . A tilting angle or a rotatable tilting range which can be set in adjustment of an angle of field is regulated by firmware. 
     First, when the light-shielding unit  901  is retracted, tilting is performed in the negative rotation direction and tilting is performed to a tilting angle of −20 degrees which is a negative end of the rotatable tilting range. 
     Specifically, as illustrated in  FIG. 6A , at a tilting angle of 0 degrees, the pressing unit  904   c  of the lens barrel holder  904  comes into contact with a pressed unit  901   c  of the light-shielding unit  901 . When the tilting is further performed in the negative rotation direction from this state, the pressing unit  904   c  of the lens barrel holder  904  presses the pressed unit  901   c  of the light-shielding unit  901  downward, so that the light-shielding unit  901  is retracted downward along the guide pole  9072   a.  At this time, when a slope surface of a lock claw  901   b  of the light-shielding unit  901  comes into contact with a slope surface of a lock claw  909   a  of the lock member  909 , a force applied forward works on the lock claw  909   a  and the lock member  909  starts sliding forward along the guide groove  9072   b.  When the lens barrel holder  904  is rotated to a tilting angle of - 20  degrees, the slope surface of the lock claw  901   b  does not come into contact with the slope surface of the lock claw  909   a.  Therefore, the lock member  909  is pushed backward along the guide groove  9072   b  by the lock member urging spring  911 . As illustrated in  FIG. 6B , the lock claw  901   b  engages with the lock claw  909   a  and a locked state, that is, a state in which the light-shielding unit  901  is retracted away from the protective cover  6 , is maintained. Thus, even in a state in which the lens barrel holder  904  is not pressed against the pressing unit  904   c,  the light-shielding unit  901  is held at the position at which the light-shielding unit  901  is retracted downward and there is a gap between the protective cover adhesion surface  901   a  of the light-shielding unit  901  and the protective cover  6 . Accordingly, the light-shielding unit  901  can be retracted away from the protective cover  6  using the stepping motor  906   a  for tilting as a power source. For example, friction does not occur between the light-shielding unit  901  and the protective cover  6  in shifting, and the lens barrel  902  can be shifted and tilted through an electromotion so that an angle of field can be adjusted. When the adjustment of the angle of field is completed, a tilting angle after the adjustment of the angle of field calculated from the number of driving pulses of the stepping motor  906   a  after the tilting initial alignment is stored in firmware. In the description, the tilting angle after the adjustment of the angle of field is assumed to be +45 degrees. 
     Subsequently, when the light-shielding unit  901  retracted downward is returned to its original position, the lens barrel holder  904  is tilted in the positive rotation direction to be tilted to a tilting angle of +125 degree which is the positive end of the rotatable tilting range. 
     Specifically, as illustrated in  FIG. 7A , at a tilting angle of + 122  degrees, the pressing unit  905   a  of the rear cover  905  comes into contact with a pressed unit  909   b  of the lock member  909 . When the lens barrel holder  904  is further tilted in the positive rotation direction from this state, the pressing unit  905   a  of the rear cover  905  presses the pressed unit  909   b  of the lock member  909  forward, so that the lock member  909  slides forward along the guide groove  9072   b.  When the lens barrel holder  904  is rotated to a tilting angle of +125 degrees, the engaged state of the lock claw  901   b  of the light-shielding unit  901  and the lock claw  909   a  of the lock member  909  is released. Therefore, as illustrated in  FIG. 7B , the light-shielding unit  901  is pushed back toward the protective cover  6  along the guide pole  9072   a  by the light-shielding unit urging spring  910 , so that the protective cover adhesion surface  901   a  is adhered to the inner surface of the protective cover  6 . Thereafter, when the lens barrel holder  904  is tilted in the negative rotation direction to the stored tilting angle of +45 degrees after the adjustment of the angle of field, the lock member  909  is pushed backward along the guide groove  9072   b  by the lock member urging spring  911  and is held at a position at which the lock member  909  comes into contact with the first tilting base  9071 . 
     In the embodiment, the locking of the light-shielding unit in the negative end of the rotatable tilting range has been described as a mechanism that releases the lock of the light-shielding unit in the positive end of the rotatable tilting range, but the present invention is not limited thereto. For example, a mechanism that has a reverse relation thereto may be used or a mechanism that performs the locking and unlocking in the same end may be used. A configuration may be used in which the locking or unlocking is performed when the lens barrel  902  is tilted beyond the range of the tilting angle which can be set in adjustment of the angle of field despite it not being the end. 
     In the above-described configuration, in the imaging device which is capable of adjusting an angle of field through an electromotion and includes the plurality of imaging units disposed along a circumferential direction, the light-shielding member can be retracted even though an actuator for retracting the light-shielding member is not separately provided. 
     A preferred embodiment of the present invention has been described, but the present invention is not limited to such an embodiment and various modifications and changes can be made within the scope of the gist of the present invention. The light-shielding unit  901  preferably has the configuration in which the lens barrel  902  is covered, but another configuration may be used. For example, at least a part of the light-shielding unit  901  is disposed between the lens barrel  902  and the infrared illumination  12   a  and a surface corresponding to the protective cover adhesion surface  901   a  is disposed to adhere to the protective cover  6 . In such disposition, a configuration may be used in which the light-shielding unit  901  can shield reflected light of the infrared illumination  12   a  in the protective cover  6  so that the reflected light does not arrive at the lens barrel  902 . The light-shielding unit  901  can be retracted away from the protective cover  6  using the stepping motor  906   a  for tilting as a power source, or a stepping motor for panning or a stepping motor for rotation about an optical axis may be used. 
     This application claims the benefit of Japanese Patent Application No. 2021-009533, filed Jan. 25, 2021, which is hereby incorporated by reference wherein in its entirety.