Lens barrel and camera with lens barrel

Abstract

A lens barrier is opened/closed by a barrier drive cylinder disposed on an outer peripheral side of a lens. The barrier drive cylinder is rotated by a rotation of a cam cylinder together with a first cylinder so as to move forward and backward. In the course of a movement of the lens from a retracted position to a shooting position, the barrier drive cylinder rotates such that a drive ring biased to an opening direction by a spring is driven into an opening direction. The barrier is, thus, opened. When the lens is moved from the shooting position to the retracted position, the operation reverse to the aforementioned is performed to close the barrier. An annular seal member is provided into the space between the barrier drive cylinder and the first cylinder so as to prevent water from entering into the barrel.

1 . A lens barrel comprising: 
 a lens provided in a lens chamber within the lens barrel;    a lens barrier that is opened and closed in front of the lens;    a barrier drive cylinder provided on an outer peripheral side of the lens so as to be allowed to rotate about an optical axis relative to a member provided on an inner peripheral side of the barrier drive cylinder;    a first link mechanism that rotates the barrier drive cylinder;    a second link mechanism that opens and closes the lens barrier interlocking with a rotation of the barrier drive cylinder; and    an annular seal member that is provided into a space between the barrier drive cylinder and the member provided on the inner peripheral side over an entire circumference.    
   
   
       2 . The lens barrel according to  claim 1 , wherein: 
 the lens is allowed to move forward and backward along the optical axis for performing an operation of zooming or focusing; and    the first link mechanism interrupts the rotation of the barrier drive cylinder when the lens moves forward and backward for performing the operation of zooming or focusing.    
   
   
       3 . The lens barrel according to  claim 1 , wherein: 
 the lens is allowed to move forward and backward in a range between a shooting position and a non-shooting position along the optical axis; and    the first link mechanism rotates the barrier drive cylinder interlocking with the lens that moves forward and backward.    
   
   
       4 . The lens barrel according to  claim 3 , wherein: 
 the lens that has reached the shooting position is further allowed to move forward and backward along the optical axis for an operation of zooming or focusing; and    the first link mechanism interrupts the rotation of the barrier drive cylinder when the lens moves forward and backward for performing the operation of zooming or focusing.    
   
   
       5 . The lens barrel according to  claim 4 , wherein 
 the first link mechanism rotates the barrier drive cylinder only when the lens moves in a part of the range between the shooting position and the non-shooting position.    
   
   
       6 . The lens barrel according to  claim 3 , wherein the first link mechanism comprises: 
 a rotary cylinder that rotates about the optical axis on the outer peripheral side of the lens so as to generate a force that moves the lens and the barrier drive cylinder along the optical axis; and    a straight guide member that guides the lens to move straight along the optical axis, and applies a rotating force around the optical axis to the barrier drive cylinder that moves along the optical axis.    
   
   
       7 . The lens barrel according to  claim 1 , wherein the second link mechanism comprises: 
 a drive force generation member that generates a drive force for opening and closing the lens barrier; and    a transfer mechanism that opens the lens barrier through a transfer of the drive force to the lens barrier interlocking with a rotation of the barrier drive cylinder in one direction, and closes the lens barrier without the transfer of the drive force interlocking with a rotation of the barrier drive cylinder in an opposite direction.    
   
   
       8 . The lens barrel according to  claim 6 , wherein the second link mechanism comprises: 
 a drive force generation member that generates a drive force for opening and closing the lens barrier; and    a transfer mechanism that opens the lens barrier through a transfer of the drive force to the lens barrel interlocking with a rotation of the barrier drive cylinder in one direction, and closes the lens barrier without the transfer of the drive force interlocking with a rotation of the barrier drive cylinder in an opposite direction.    
   
   
       9 . The lens barrel according to  claim 7 , wherein the transfer mechanism is provided closer to a front of the lens barrel than the seal member.  
   
   
       10 . The lens barrel according to  claim 8 , wherein 
 the transfer mechanism is provided closer to a front of the lens barrel than the seal member.    
   
   
       11 . A camera comprising the lens barrel according to  claim 1 .  
   
   
       12 . A camera comprising the lens barrel according to  claim 10 .  
   
   
       13 . A lens barrel comprising: 
 lenses provided in a lens chamber within the lens barrel;    a lens barrier that is opened and closed in front of the lenses; and    a barrier block that is provided near an inlet of the lens chamber so as to be movable along an optical axis, is capable of holding the lens barrier in an open state and a closed state, comprises a barrier retraction space where the lens barrier in the opened state is received, and changes a volume of a rear portion of the lens chamber according to a movement of the barrier block along the optical axis, wherein:    the barrier block has a drain hole which communicates the barrier retraction space with an outside of the lens barrel, and an air passage formed near the drain hole which communicates the barrier retraction space with the rear portion of the lens chamber, such that an air flow directed from the rear portion of the lens chamber toward the barrier retraction space is generated in the air passage when the barrier block moves backward.    
   
   
       14 . The lens barrel according to  claim 13 , wherein: 
 the barrier unit includes at least a part of the lenses and a holding member thereof; and    apart of the air passage is an air hole formed in the holding member.    
   
   
       15 . The lens barrel according to  claim 13 , wherein 
 a metal function member within the lens barrel is disposed in the air passage.    
   
   
       16 . The lens barrel according to  claim 13 , wherein 
 the air passage is sealed with a gas permeable water-repellent sheet.    
   
   
       17 . The lens barrel according to  claim 13 , wherein 
 a plurality of the air passages are formed in the barrier block.    
   
   
       18 . The lens barrel according to  claim 13 , wherein: 
 a metal function member within the lens barrel is disposed in the air passage;    the air passage is sealed with a gas permeable water-repellent sheet and    a plurality of the air passages are formed in the barrier block.    
   
   
       19 . A camera comprising the lens barrel according to  claim 13 .  
   
   
       20 . A lens barrel comprising: 
 a lens provided in a lens chamber within the lens barrel;    a lens barrier that is opened and closed in front of the lens;    a barrier drive cylinder provided on an outer peripheral side of the lens so as to be allowed to rotate about an optical axis relative to a member provided on an inner peripheral side of the barrier drive cylinder;    a first link mechanism that rotates the barrier drive cylinder;    a second link mechanism that opens and closes the lens barrier interlocking with a rotation of the barrier drive cylinder;    an annular seal member that is provided into a space between the barrier drive cylinder and the member provided on the inner peripheral side over an entire circumference; and    a barrier block that is provided near an inlet of the lens chamber so as to be movable along an optical axis, is capable of holding the lens barrier in an open state and a closed state, comprises a barrier retraction space where the lens barrier in the opened state is received, and changes a volume of a rear portion of the lens chamber according to a movement of the barrier block along the optical axis, wherein:    the barrier block has a drain hole which communicates the barrier retraction space with an outside of the lens barrel, and an air passage formed near the drain hole which communicates the barrier retraction space with the rear portion of the lens chamber, such that an air flow directed from the rear portion of the lens chamber toward the barrier retraction space is generated in the air passage upon when the barrier block moves backward.    
   
   
       21 . A camera comprising the lens barrel according to  claim 20.