Lens barrier opening/closing device of a movable lens barrel

Abstract

A lens barrier opening/closing device of a movable lens barrel includes a barrier blade which is driven to open and close a photographic aperture; a barrier drive ring driven to rotate about an optical axis; a first biasing device which biases the barrier drive ring in a rotational direction; a rotational barrel which rotates about the optical axis; a receiving surface formed on the barrier drive ring to extend parallel to the optical axis; and a transmission surface, formed on the rotational barrel, extending parallel to the optical axis. The receiving surface and the transmission surface are engaged with each other to rotate the barrier drive ring together with the rotational barrel about the optical axis in a direction against a biasing force of the first biasing device when the movable lens barrel moves from either the photographing position to the accommodation position or vise versa.

1. A lens barrier opening/closing device of a movable lens barrel driven to move between an accommodation position and a photographing position, comprising:
 at least one barrier blade which is driven to open and close a photographic aperture formed at the front end wall of said movable lens barrel when said movable lens barrel is in said photographing position and said accommodation position, respectively;  
 a barrier drive ring driven to rotate about an optical axis to drive said at least one barrier blade;  
 a first biasing device which biases said barrier drive ring in a predetermined rotational direction;  
 a rotational barrel which at least rotates about said optical axis when said movable lens barrel moves between said accommodation position and said photographing position;  
 a rotational-force receiving surface formed on said barrier drive ring, said rotational force receiving surface extending parallel to said optical axis; and  
 a rotational-force transmission surface formed on said rotational barrel, said rotational-force transmission surface extending parallel to said optical axis,  
 wherein said rotational-force receiving surface and said rotational-force transmission surface are engaged with each other to rotate said barrier drive ring together with said rotational barrel about said optical axis in a direction against a biasing force of said first biasing device when said movable lens barrel moves from one of said photographing position and said accommodation position to the other of said photographing position and said accommodation position.  
 
     
     
       2. The lens barrier opening/closing device according to  claim 1 , wherein said barrier drive ring comprises a drive lever which extends substantially parallel to the optical axis toward said rotational barrel, said drive lever including said rotational-force receiving surface thereon. 
     
     
       3. The lens barrier opening/closing device according to  claim 2 , wherein said rotational barrel comprises a recess formed to allow said drive lever to enter said recess, said rotational-force transmission surface being formed as a wall of said recess. 
     
     
       4. The lens barrier opening/closing device according to  claim 1 , wherein said movable lens barrel is an element of a zoom lens of a camera. 
     
     
       5. The lens barrier opening/closing device according to  claim 1 , wherein said first biasing device comprises at least one helical extension spring. 
     
     
       6. The lens barrier opening/closing device according to  claim 1 , wherein said barrier drive ring and said rotational barrel rotate relative to each other about said optical axis and move relative to each other in a direction of said optical axis when said movable lens barrel moves between said photographing position and said accommodation position, and
 wherein said barrier drive ring and said rotational barrel are apart from each other so that said rotational-force receiving surface and said rotational-force transmission surface do not overlap each other in said direction of said optical axis when said movable lens barrel is in a specific one of said photographing position and said accommodation position in which said rotational barrel does not drive said barrier drive ring to rotate about said optical axis via said rotational-force receiving surface and said rotational-force transmission surface.  
 
     
     
       7. The lens barrier opening/closing device according to  claim 6 , further comprising:
 a linearly movable barrel positioned around said rotational barrel, guided in said direction of said optical axis without rotating about said optical axis, and supporting said barrier drive ring in a front end of said linearly movable barrel so that said barrier drive ring is rotatable about said optical axis;  
 a radially inward pin formed on said linearly movable barrel to extend radially inwards; and  
 a guide groove, corresponding to said radially inward pin, formed on an outer peripheral surface of said rotational barrel to be engaged with said radially inward pin to move said linearly movable barrel in said direction of said optical axis by rotation of said rotational barrel.  
 
     
     
       8. The lens barrier opening/closing device according to  claim 7 , wherein said movable lens barrel is an element of a zoom lens of a camera, and
 wherein said linearly movable barrel functions as a movable lens hood which advances relative to said rotational barrel when said zoom lens is set at a telephoto extremity thereof having a narrow angle of view, and which retreats relative to the rotational barrel when said zoom lens is set at a wide-angle extremity thereof having a wide angle of view.  
 
     
     
       9. The lens barrier opening/closing device according to  claim 1 , further comprising:
 a second biasing device which biases said barrier blade in a direction toward one of an open position and a closed position of said barrier blade against the biasing force of said first biasing device, a biasing force of said second biasing device being smaller than that of said first biasing device,  
 wherein said barrier blade is driven by said biasing force of said second biasing device when said barrier drive ring is driven to rotate against said biasing force of said first biasing device by rotation of said rotational barrel.  
 
     
     
       10. The lens barrier opening/closing device according to  claim 9 , wherein said second biasing device comprises at least one torsion spring. 
     
     
       11. A lens barrier opening/closing device of a movable lens barrel, comprising:
 at least one barrier blade which is driven to open and close a photographic aperture formed at the front end wall of said movable lens barrel;  
 a rotational barrel which at least rotates about an optical axis when said movable lens barrel moves between an accommodation position and a photographing position;  
 a barrier drive ring driven to rotate about said optical axis to drive said barrier blade;  
 an opening biasing device which biases said barrier drive ring in a direction to open said barrier blade;  
 a rotational-force receiving surface formed on said barrier drive ring, said rotational-force receiving surface extending parallel to said optical axis; and  
 a rotational-force transmission surface formed on said rotational barrel, said rotational-force transmission surface extending parallel to said optical axis,  
 wherein said rotational-force receiving surface and said rotational-force transmission surface are engaged with each other to rotate said barrier drive ring about said optical axis in a direction to close said barrier blade against said biasing force of said opening biasing device while said rotational barrel rotates when said movable lens barrel moves from said photographing position to said accommodation position.  
 
     
     
       12. The lens barrier opening/closing device according to  claim 11 , further comprising a linearly movable barrel guided in a direction of said optical axis without rotating about said optical axis, said linearly movable barrel supporting said barrier drive ring at a front end thereof so that said barrier drive ring is rotatable about said optical axis. 
     
     
       13. The lens barrier opening/closing device according to  claim 11 , further comprising:
 at least one engaging portion formed on said barrier drive ring to be engageable with said barrier blade; and  
 a closing biasing device which biases said barrier blade in a direction to close said photographic aperture, a biasing force of said closing biasing device being smaller than that of said opening biasing device,  
 wherein said engaging portion of said barrier drive ring held at a position to open said barrier blade by said biasing force of said opening biasing device pushes said barrier blade to open said barrier blade when said movable lens barrel is in said photographing position, and  
 wherein said engaging portion is disengaged from said barrier blade so that said barrier blade is driven to be closed by said biasing force of said closing biasing device when said barrier drive ring is driven to rotate about said optical axis against said biasing force of said opening biasing device by rotation of said rotational barrel when said movable lens barrel moves from said photographing position to said accommodation position.  
 
     
     
       14. A camera comprising:
 a movable lens barrel driven to move between a photographing position an accommodation position when the power of said camera is turned ON and OFF, respectively;  
 at least one barrier blade driven to open and close a photographic aperture formed at the front of said movable lens barrel when said movable lens barrel is in said photographing position and said accommodation position, respectively;  
 a barrier drive ring driven to rotate about an optical axis to drive said at least one barrier blade;  
 at least one spring which biases said barrier drive ring in a direction to open said barrier blade;  
 a rotational barrel which rotates about said optical axis when said movable lens barrel moves between said accommodation position and said photographing position;  
 a lever formed on said barrier drive ring to extend toward said rotational barrel, said lever including a first engaging surface extending parallel to said optical axis; and  
 a recess formed on said rotational barrel so that said lever can enter said recess in a direction of said optical axis, said recess including a second engaging surface extending parallel to said optical axis,  
 wherein said first engaging surface and said second engaging surface are engaged with each other to rotate said barrier drive ring about said optical axis in a direction to close said barrier blade against said biasing force of said biasing device when said movable lens barrel moves from said photographing position to said accommodation position.  
 
     
     
       15. A lens barrier opening/closing device of a movable lens barrel driven to move between an accommodation position and a photographing position, comprising:
 at least one barrier blade which is driven to open and close a photographic aperture formed at the front end wall of said movable lens barrel when said movable lens barrel is in said photographing position and said accommodation position, respectively;  
 a linearly movable barrel guided in a direction of an optical axis without rotating about said optical axis;  
 a barrier drive ring driven to rotate about said optical axis to drive said barrier blade, said linearly movable barrel supporting said barrier drive ring in a front end of said linearly movable barrel to be rotatable about said optical axis; and  
 a pair of ring biasing springs positioned between said barrier drive ring and said linearly movable barrel on opposite sides with respect to said optical axis in a radial direction to bias said barrier drive ring in a predetermined rotational direction,  
 wherein said barrier ring is driven to rotate in a rotational direction opposite to said predetermined rotational direction against a biasing force of said pair of ring biasing springs by a movement of a movable member provided in said lens barrel when said movable lens barrel moves from one of said photographing position and said accommodation position to the other of said photographing position and said accommodation position.  
 
     
     
       16. The lens barrier opening/closing device according to  claim 15 , further comprising:
 at least one barrier biasing spring which biases said barrier blade in a direction opposite to a biasing direction of said pair of ring biasing springs toward one of an open position and a closed position of said barrier blade,  
 wherein a biasing force of said barrier biasing spring is smaller than that of said pair of ring biasing springs, and  
 wherein said barrier blade is driven by said biasing force of said barrier biasing spring to move to one of said open position and said closed position when said barrier drive ring is driven to rotate against said biasing force of said pair of ring biasing springs.  
 
     
     
       17. The lens barrier opening/closing device according to  claim 16 , wherein said at least one barrier blade comprises at least one pair of barrier blades,
 wherein said at least one barrier biasing spring comprises a pair of barrier biasing springs positioned on opposite sides with respect to said optical axis in said radial direction of said at least one pair of barrier blades in a radial direction to bias each of said at least one pair of barrier blades toward one of said open position and said closed position,  
 wherein said barrier drive ring comprises at least one pair of engaging portions which can be engaged with said at least one pair of barrier blades, respectively,  
 wherein said barrier drive ring is engaged with at least one pair of said barrier blades to push said at least one pair of barrier blades via said at least one pair of engaging portions against a biasing force of said pair of barrier biasing springs when driven to rotate about said optical axis in said predetermined rotational direction, and  
 wherein said barrier drive ring is disengaged from said at least one pair of barrier blades when driven to rotate about the optical axis against a biasing force of said pair of ring biasing springs via said movement of said movable member.  
 
     
     
       18. The lens barrier opening/closing device according to  claim 15 , wherein said linearly movable barrel comprises a pair of first protrusions positioned on opposite sides with respect to said optical axis in said radial direction,
 wherein said barrier drive ring comprises a pair of second protrusions positioned on opposite sides with respect to said optical axis in said radial direction,  
 wherein said pair of ring biasing springs are formed as two helical extension springs, and  
 wherein the opposite ends of one of said two helical extension springs are connected to one of said pair of first protrusions and one of said pair of second protrusions, respectively, while the opposite ends of the other of said two helical extension springs are connected to the other of said pair of first protrusions and the other of said pair of second protrusions, respectively.  
 
     
     
       19. The lens barrier opening/closing device according to  claim 15 , wherein said pair of ring biasing springs bias said barrier drive ring in a first rotational direction to drive said barrier blade to open said photographic aperture, and
 wherein said barrier drive ring is driven to rotate in a second rotational direction opposite to said first rotational direction to drive said barrier blade to close said photographic aperture when said movable lens barrel moves from said photographing position to said accommodation position.  
 
     
     
       20. The lens barrier opening/closing device according to  claim 15 , wherein said barrier biasing spring comprises at least one torsion spring. 
     
     
       21. The lens barrier opening/closing device according to  claim 15 , wherein said movable lens barrel is an element of a zoom lens of a camera. 
     
     
       22. The lens barrier opening/closing device according to  claim 21 , wherein said linearly movable barrel functions as a movable lens hood which advances relative to said rotational barrier when said zoom lens is set at a telephoto extremity thereof having a narrow angle of view, and which retreats relative to the rotational barrel when said zoom lens is set at a wide-angle extremity thereof having a wide angle of view. 
     
     
       23. A camera comprising:
 a movable lens barrel driven to move between a photographing position an accommodation position when the power of said camera is turned ON and OFF, respectively;  
 at least one barrier blade driven to open and close a photographic aperture formed at the front of said movable lens barrel when said movable lens barrel is in said photographing position and said accommodation position, respectively;  
 a linearly movable barrel guided in a direction of an optical axis without rotating about said optical axis;  
 a barrier drive ring driven to rotate about said optical axis to drive said barrier blade, said linearly movable barrel supporting said barrier drive ring in a front end thereof so that said barrier drive ring is rotatable about said optical axis;  
 a rotational barrel which rotates about said optical axis when said movable lens barrel moves between said accommodation position and said photographing position; and  
 a pair of springs positioned between said barrier drive ring and said linearly movable barrel on opposite sides, with respect to said optical axis in a radial direction, to bias said barrier drive ring in a predetermined rotational direction,  
 wherein said barrier drive ring is driven to rotate in a rotational direction opposite to said biased rotational direction by rotation of said rotational barrel when said movable lens barrel moves from one of said photographing position and said accommodation position to the other of said photographing position and said accommodation position.  
 
     
     
       24. The lens barrier opening/closing device according to  claim 1 , further comprising a moving mechanism that moves said barrier drive ring and said rotational barrier so that a relative distance between said rotational barrier and said barrier drive ring along the optical axis is varied in accordance with rotation of said rotational barrel. 
     
     
       25. The lens barrier opening/closing device according to  claim 11 , further comprising a moving mechanism that moves said barrier drive ring and said rotational barrier so that a relative distance between said rotational barrier and said barrier drive ring along the optical axis is varied in accordance with rotation of said rotational barrel. 
     
     
       26. The camera according to  claim 14 , further comprising a moving mechanism that moves said barrier drive ring and said rotational barrier so that a relative distance between said rotational barrier and said barrier drive ring along the optical axis is varied in accordance with rotation of said rotational barrel. 
     
     
       27. The lens barrier opening/closing device according to  claim 15 , further comprising:
 a rotational barrel which at least rotation about said optical axis when said linearly movable lens barrel moves between said accommodation position and said photographing position; and  
 a moving mechanism that moves said barrier drive ring and said rotational barrier so that a relative distance between said rotational barrier and said barrier drive ring along the optical axis is varied in accordance with rotation of said rotational barrel.  
 
     
     
       28. The camera according to  claim 23 , further comprising a moving mechanism that moves said barrier drive ring and said rotational barrier so that a relative distance between said rotational barrier and said barrier drive ring along the optical axis is varied in accordance with rotation of said rotational barrel. 
     
     
       29. A collapsible lens barrel comprising:
   a plurality of lens groups having an optical axis, and movable along the optical axis to change the relative position of said plurality of lens groups;        a rotatable cam barrel configured to move between an accommodated position and a photographing range by rotating; and        a drive ring, configured to move between the accommodated position and the photographing range, wherein:      when said drive ring is within the photographing range, said drive ring is configured to move along the optical axis without rotating; and        when said drive ring is moved from the photographing range to the accommodated position, said drive ring is configured to move along the optical axis and rotate by contacting said rotatable cam barrel.       
     
     
       30. The collapsible lens barrel according to  claim 29 , further comprising a barrier blade, wherein said drive ring is configured to drive said barrier blade to close a photographic aperture formed at an object side of the lens barrel. 
     
     
       31. The collapsible lens barrel according to  claim 29 , wherein said plurality of lens groups includes a rearmost lens group configured to focus an image produced by said plurality of lens groups. 
     
     
       32. The collapsible lens barrel according to  claim 29 , further comprising a plurality of shutter blades, wherein said plurality of lens groups comprise a first lens group and a second lens group, with said plurality of shutter blades positioned between said first lens group and said second lens group. 
     
     
       33. The collapsible lens barrel according to  claim 29 , further comprising a stationary barrel configured to support said plurality of lens groups, said rotatable cam barrel and said drive ring. 
     
     
       34. A digital camera having a body and comprising:
   a plurality of lens groups having an optical axis, and movable along the optical axis to change the relative position of said plurality of lens groups;        an image sensor configured to receive light passed through said lens groups, said image sensor further configured to generate an image signal;        a collapsible lens barrel configured to house said plurality of lens groups, said lens barrel housed within the body and comprising:      a rotatable cam barrel configured to move between an accommodated position and a photographing range by rotating; and        a drive ring, configured to move between the accommodated position and the photographing range, wherein:      when said drive ring is within the photographing range, said drive ring is configured to move along the optical axis without rotating; and        when said drive ring is moved from the photographing range to the accommodated position, said drive ring is configured to move along the optical axis and rotate by contacting said rotatable cam barrel.         
     
     
       35. The camera according to  claim 34 , further comprising a barrier blade, wherein said drive ring is configured to drive said barrier blade to close a photographic aperture formed at an object side of the lens barrel. 
     
     
       36. The camera according to  claim 34 , wherein said plurality of lens groups includes a rearmost lens group configured to focus an image produced by said plurality of lens groups. 
     
     
       37. The camera according to  claim 34 , further comprising a plurality of shutter blades, wherein said plurality of lens groups comprise a first lens group and a second lens group, with said plurality of shutter blades positioned between said first lens group and said second lens group. 
     
     
       38. The camera according to  claim 34 , further comprising a stationary barrel affixed to said body and configured to support said collapsible lens barrel.