Patent Document

CROSS-REFERENCE TO RELATED APPLICATION 
     The present application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2001-202506, filed Jul. 3, 2001. The entire contents of the application are incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a camera having a forwardly and backwardly movable lens barrel of a photographic lens and a lens-protecting barrier (lens barrier) which can be opened and closed in front of the photographic lens. 
     2. Description of the Related Art 
     With the advancement of compact designs, recent cameras with barriers tend to be designed so that the distal ends of the lens barrels and the front faces of the camera bodies, located on the same planes when the lens barrels are retracted. 
     For example, Japanese Published Patent Application H01-131539 discloses a camera that has a lens barrier and a lens barrel being retractable in the camera main body. 
     This camera is equipped with a barrier (lens barrier) for the protection of the front part of a photographic lens. The barrier can be opened and closed in front of the lens. FIG. 20 is a cross-sectional view showing the surroundings of the lens barrel of the camera when the barrier is locked to the camera. 
     In FIG. 20, reference numeral  101  represents the lens barrel, reference numeral  104  represents the barrier, reference numeral  104   a  represents a fitting portion (lock pin cutout) formed in the barrier, reference numeral  110  represents a lock pin and reference numeral  111  represents a leaf spring. As shown in FIG. 20, when the lens barrel  101  is extracted (protruding) from the camera main body, the lock pin  110  locks the barrier  104  at an open position so as to prevent the barrier  104  from being moved in a closing direction and contacting the lens barrel  101 . Consequently, when the lens barrel  101  is located at the extended position, the barrier  104  does not interfere with the lens barrel  101  even when the barrier  104  is pressed in the P direction, and thus the forward or backward movement of the lens barrel  101  is not disturbed. 
     In the disclosed camera, when the barrier is in the closed position, the periphery of the lower portion of the retracted lens barrel  101  presses the L-shaped portion of the lock pin  110  against the urging force (tension) of the leaf spring  111  to move the lock pin  110  down. When the barrier  104  is opened, the lens barrel  101  starts to extract from the retracted state. At a specific point of this extraction, the pressing force on the lock pin  110  by the lower flange of the lens barrel  101  is released, and the lock pin  110  is pushed out to the front side of the camera by the urging force of the leaf spring  111  and engages with the fitting portion (lock pin cutout)  104   a  to lock the barrier  104 . As a result of the described process, there is some time lag between the time at which the barrier  104  reaches to the open position and the time at which it is locked. Therefore, if an operator presses the barrier  104  in the closing direction P just after he or she opens it, the barrier  104  might move in the closing direction P and hit the lens barrel,  101  or the lens barrel  101  might touch the back surface of the barrier  104 . Therefore, the mechanism described above for extracting the lens barrel  101  can cause damage by the contact between the barrier  104  and the lens barrel  101 . 
     The present invention provides an improved mechanism for extracting and retracting lens barrels, and/or for locking and unlocking a lens barrier to avoid contact between the lens barrel and lens barrier caused by an error. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention relates to a camera equipped with a forwardly and backwardly movable photographic lens and a lens protecting barrier (lens barrier) which can be opened and closed in front of the photographic lens. The present invention has some technical features to reduce the risk of contact between the barrier and the photographic lens caused by careless operation of the camera. All the technical features may be used to implement the present invention; however, each one of the technical features has a unique merit for implementation. Consequently, it is not required to implement all the technical features of the present invention. A user of the present invention may use some or all of the technical features which are necessary in accordance with his or her situation. 
     In various embodiments of the present invention, the camera of the present invention may be a film camera, a digital camera, a video camera or any electronic equipment (for example, a cellular phone, a computer, PDA) having a camera installed therein. 
     In the present invention, a photographic lens includes a photographic lens and a lens barrel holding the photographic lens unless the photographic lens and the lens barrel are distinguishably described. 
     The present invention is designed to be used with a camera having a photographic lens which can be forwardly and backwardly moved along the optical axis direction of the lens system and a barrier which can cover the front face or a portion of the front face of the photographic lens when the lens is retracted. The barrier is movable between a closed position at which it covers the front face of the photographic lens or a portion of the front face and a retreated position at which it does not cover the front face of the photographic lens. The path of the photographic lens and the path of the barrier cross each other; therefore the barrier must locate at the retreated position when the photographic lens moves forward or backward and may locate at the closed position only when the photographic lens is retracted in the camera main body. 
     The first technical feature of the invention resides in that when the barrier is opened, the barrier is locked by using the movement of the barrier itself to the retreated position (the barrier is to be locked at least so as not to be moved in the closing direction). Specifically, the lock operation of the barrier is caused directly by the movement of the barrier to the retreated position, whereby the barrier can be quickly locked when it is moved to the retreated position. As an example to implement this lock operation, the lock member for locking the barrier may be kept under tension in the locking direction so that it can automatically and immediately lock the barrier by the urging force when the barrier comes to the retracted position, and thereby the locking operation becomes possible. 
     The second technical feature of the invention resides in that, in the first technical feature, the forward movement of the photographic lens is started only after the barrier lock by the lock member is accomplished. By this technical feature, even when the barrier is pressed in the closing direction during the forward movement of the photographic lens, the barrier cannot be moved in the closing direction because it has already been locked. Consequently, the contact between the barrier and the photographic lens can be effectively prevented. As an example to achieve this feature, a switch is provided to detect that the barrier has reached the position where it is to be locked, and the detection makes a motor start to drive the photographic lens in advancing direction. 
     The third technical feature of the invention resides in that, in a phase of retracting the photographic lens into the camera main body and subsequently closing the lens barrier, the lock of the barrier is released by using the retracting motion of the photographic lens. With this feature, the timing for releasing the barrier&#39;s lock can be preferably chosen in connection with the retracting photographic lens&#39;s current position. The releasing timing can be chosen with reference to the photographic lens&#39;s position, thereby it is possible to defer the release of the barrier&#39;s lock until after the photographic lens has sufficiently retracted. Thus there is no possibility of contact between the barrier and the photographic lens with respect to each other, even if the barrier is pushed in the closing direction. As an example to achieve this feature, a member for releasing the barrier lock (lock-release engaging portion) is provided on the photographic lens. This member engages with the lock member during the retraction of the photographic lens, and pushes the lock member by using the retraction movement to unlock it. 
     The fourth technical feature of the invention resides in that, in the third technical feature, a mechanism for avoiding the engagement between the lock-release engaging portion and the lock member during the advancement of the photographic lens is adopted. The lock-release engaging portion which engages with the lock member during retraction of the photographic lens may also engage with the lock member during advancement of the photographic lens, because the photographic lens usually advances and retracts along the same path. The lock-release engaging portion is intended to operate only in the retracting movement of the photographic lens, thus the engagement in the advancing movement of the photographic lens may cause some unexpected problems. This mechanism is provided to avoid the problems. As an example to achieve this feature, a slant surfaces are provided on the surfaces, onto which the lock-release engaging portion and the lock member contact each other during the advancing movement of the photographic lens, so that the lock-release engaging portion and the lock member slide on each other along the slant surfaces during the advancing movement of photographic lens. This sliding movement applies the force in a direction different than the advancing direction of the photographic lens to the lock member, thereby the force moves the lock member out of the engaging position. 
     The fifth technical features of the invention resides in that the engagement of the lock-release engaging portion and the lock member is released by using the closing operation of the barrier. When the release of the lens barrier is to be made, the lock-release engaging portion engages the lock member during the retracting movement of the photographic lens. The lock-release engaging portion pushes the lock member to unlock the lens barrier by using the retracting movement of the photographic lens. But after the releasing of the lock, the lock-release engaging portion may still be engaged and push the lock member, thus the lock member can not lock the barrier again until the engagement with the lock-release engaging portion is released. Therefore, it is required to release the engagement between the lock-release engaging potion and the lock member after the unlocking of the lens barrier is accomplished. In this feature of the invention, the engagement is released by using the closing operation of the barrier. As an example to achieve this feature, it is desirable to provide a lock engaging portion on the lens barrier for engaging with the lock member during the lens barrier&#39;s closing operation. This lock engaging portion engages with the lock member, pushes it by the closing movement of the barrier, whereby the engagement between the lock member and the lock-release engaging portion is released. 
     The sixth technical feature of the invention resides in that, two specific positions are specified as positions of the retreated lens barrier with respect to the photographic lens&#39; path (two positions are appointed from along the lens barrier&#39;s path in which the lens barrier is retreated from the photographic lens&#39;s path). One is a semi-open position at which the lens barrier is to be locked (to prevent motion in closing direction), and the other is an open position at which the barrier is more widely opened and is detected by a switch. The switch is used to control the driving motor of the photographic lens. When the barrier comes into the open position, it is detected with the switch, and then the photographic lens starts the forward motion from the retracted position. On the other hand, when the barrier is detached from the switch, the retracting motion of the photographic lens is started. Therefore, the driving of the photographic lens is carried out in connection with the opening and closing operation of the barrier, and it is not required to provide a button for driving the photographic lens. This is particularly effective in a case where the barrier is manually moved. With the implementation of the technical feature, there is some extra time period between the completion of the lock and the start of the forward movement of the photographic lens (this time period corresponds with the time period in which the barrier moves from the semi-open position to the open position), so that the possibility of malfunction can be reduced. Further, when the barrier is being closed, the closing operation of the barrier is temporarily stopped at the semi-open position, and the automatic retraction of the photographic lens is started. Therefore, when (by adopting the third technical feature, for example) the lock of the barrier may be released after the photographic lens is retracted to a position at which the closing operation of the barrier is not disturbed, and thus the operation can be smoothly performed while the possibility of the contact between the photographic lens and the barrier is reduced. 
     The switch is preferably set to detect the departure of the barrier when the barrier just reaches the semi-open position from the open position, so an operator may not notice a difference between the two positions, (the barrier locking position (the semi-open position) and the motor-controlling position (the open position)), and may enjoy a smooth operational feeling. 
     The switch of the second or sixth technical feature may include mechanical types, electrical types, optical types, magnetic types or any other type of sensing device or method. In one embodiment of the invention, the switch may be, for example, a photoelectric switch. 
     In many cameras, the photographic lenses are, at least partially, sunken into the camera main bodies when they are retracted. When in this condition, the cameras are usually disabled from taking photographs. When the photographic lenses are extended from the bodies, the cameras become to be able to take photographs. However, the present invention does not require a connection between the location of the photographic lens and the operational conditions of the camera. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     FIG. 1 is a perspective view showing a barrier-attached camera in an embodiment of the present invention when the barrier is opened. 
     FIG. 2 is an exploded perspective view showing the camera of FIG. 1, when the camera is ready to take pictures and the barrier is omitted for illustration. 
     FIG. 3 is a perspective view showing the barrier mounted in the camera of FIG. 1, which is viewed from the backside of the camera, which is the opposite direction of the direction A of FIG.  1 . 
     FIG. 4 is an exploded perspective view showing a lens barrel driving mechanism portion and a barrier lock mechanism portion in the camera of FIG.  1 . 
     FIG. 5 is a view taken along the direction of C of FIG. 4 (exploded perspective view), which shows a part of the barrier lock mechanism portion. 
     FIG. 6 is a cross-sectional view taken along E—E of FIG.  5 . 
     FIGS. 7A and 7B are cross-sectional views taken along F—F of FIG. 6, wherein FIG. 7A shows the state of the tip of an arm portion, a driven arm and a projecting portion of a lock shaft when the barrier is located at an open position or semi-open position, and FIG. 7B shows the state of the tip of the arm portion, the driven arm and a rotation stopping projection of the lock shaft when the barrier is located at a closed position; 
     FIGS. 8A to  8 D are cross-sectional views taken along D—D, which show variation of the relative positional relationship between a driving projection and the driven arm of the lock shaft when the lens barrel is extracted; 
     FIG. 9 is a front view taken in the A direction of FIG. 1, in which the barrier is in the open state, and the camera is ready to take pictures. 
     FIG. 10 is a front view taken in the A direction of FIG. 1, in which the barrier is located at the semi-open position and the lens barrel has just started retracting. 
     FIG. 11 is a front view taken in the A direction of FIG. 1, in which the lens barrel has retracted in the body and the barrier has further moved in the closing direction from the semi-open position. 
     FIG. 12 is a front view taken in the A direction of FIG. 1, in which the barrier is closed. 
     FIG. 13 is a cross-sectional view taken along B—B of FIG. 1, in which the barrier is located at the open position and the lens barrel is extended. 
     FIG. 14 is a cross-sectional view taken along B—B of FIG. 1, in which shows the barrier is located at the semi-open position and the lens barrel starts to retract in the camera main body. 
     FIG. 15 is a cross-sectional view taken along B—B of FIG. 1, in which the barrier is located at the semi-open position and the lens barrel has just retracted in the camera main body. 
     FIG. 16 is a cross-sectional view taken along B—B of FIG. 1, in which the lens barrel has retracted and the barrier has further moved in the closing direction from the semi-open position. 
     FIG. 17 is a cross-sectional view taken along B—B of FIG. 1, in which the barrier has closed. 
     FIG. 18 is a diagram showing a main electrical control circuit of the camera of FIG.  1 . 
     FIG. 19 is a general flowchart showing the operation of the camera. 
     FIG. 20 is a cross-sectional view of the main portion around the lens barrel under the barrier locked state of the prior art camera. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Preferred embodiments of the present invention will be described hereunder with reference to the drawings. 
     FIG. 1 is a perspective view showing a barrier open state of a camera with a lens barrier  2  of one embodiment employing the present invention. FIG. 2 is an exploded perspective view of the camera in a photo-taking state, omitting the barrier  2  for illustration. FIG. 3 is a perspective view of the barrier  2  of the camera, which barrier  2  is viewed from the backside, which is the opposite direction to the A direction of FIG.  1 . 
     Further, FIGS. 9 to  12  are front views of the camera, which show the open/close state of the barrier  2  viewed in the A direction of FIG.  1 . FIG. 9 shows the camera in which the barrier  2  is at a open position and ready to take pictures. FIG. 10 shows the camera in which the barrier  2  is at a semi-open position and a lens barrel  3  is just starting to retract. FIG. 11 shows the camera in which the barrier  2  is in closing process after the lens barrel  3  has retracted. FIG. 12 shows the camera in which the barrier  2  has closed. 
     In the following description, the closing direction of the barrier  2  is referred as +X direction, and the opening direction of the barrier  2  is referred as −X direction. Further, the direction from the camera to the subject is referred as +Z direction (forward direction), and the direction from the camera lens to the film face is referred as −Z direction (backward direction). The rotational direction is indicated as the camera is viewed from the subject side. 
     As shown in FIG. 1, the camera with a barrier  2  of the embodiment shown has a barrier  2  disposed at a front face portion of a camera main body  1 . By manually operating the barrier  2  in the +X direction or the opposite direction (−X direction), the barrier  2  is movable to the open position P 2 B (see FIG. 9) and the semi-open position P 2 C (see FIG. 10) and the closed position P 2 A (See FIG.  12 ). In the open position P 2 B and the semi-open position P 2 C, the barrier  2  is retreated from the photographic lens&#39;s path (the barrier  2  is in the retreated position. In the closed position P 2 A, the barrier  2  covers a photographic lens  3   e  located at the accommodated position (retracted position). The camera is in a non-photo-taking state when the photographic lens is located at the retracted position. 
     In the camera, the photograph lens barrel (hereinafter referred to as “lens barrel”)  3  is forwardly or backwardly moved between the retracted position at which the camera can not take photographs and the extended position at which the camera can take photographs. This movement is related to the barrier&#39;s movement. 
     At the semi-open position P 2 C of the barrier  2 , the movement of the barrier  2  in the closing direction is locked (fixed), and the retracting motion of the lens barrel  3  is started. 
     The barrier  2  has a movement path between the closed position and the open position at the front side of the lens barrel  3  when the lens barrel  3  is in the retracted position. The lens barrel  3  has a movement path between the extracted position and the retracted position. The moving path of the barrier  2  and the moving path of the lens barrel  3  cross each other. That is, when the lens barrel  3  is located at the retracted position, then the lens barrel  3  is out of the moving path of the barrier  2 , and when the lens barrel  3  is located at the extracted position, the lens barrel  3  is located within the moving path of the barrier  3 . In other words, when the barrier  2  is located at the open position, the barrier  2  is out of the moving path of the lens barrel  3 , and when the barrier  2  is located at the closed position, the barrier  2  is within the moving path of the lens barrel  3 . 
     In the camera of the above embodiment, guide grooves  1   a  and  1   b , along which the barrier  2  is freely and slidably supported, are formed in parallel at the upper and lower portions of the front face  1   g  of the camera main body  1  which is an outer shell of the camera, so as to extend in the right-and-left direction as shown in FIGS. 1 to  4 . 
     The lens barrel  3  which is slidably inserted into an opening portion  1   j , (shown in FIGS. 13 to  15 ) is freely forwardly and backwardly movable in the direction of the optical axis O and is disposed at the center portion of the front face of the camera main body  1 . Further, an electronic flash window  4 , a finder window  5 , a ranging photodetecting window  6 , a ranging light emitting window  8 , a photometric window  7 , a self-timer display window  9 , etc. are disposed on the camera main body in the area above the lens barrel  3 . 
     When the barrier  2  is located at the closed position P 2 A, the barrier  2  covers the lens barrel  3 , in the retraction state, and the elements above the lens barrel  3  previously described, e.g., the ranging photodetecting window  6  and the self-timer display window  9 . 
     Further, a release button  10  for operating a release switch  10   a  (see FIG. 18) is disposed at the upper face portion of the camera main body  1 . 
     As shown in FIG. 2, a shaft hole  1   i  having a bent shape is disposed on the front face  1   g  of the camera main body  1  at the left side of the lens barrel  3 . From the shaft hole  1   i , a tip portion  19   a  of a lock shaft  19  (serving as the lock member) including an arm portion and an arm portion tip  19   b  of the arm portion is projected so as to be freely rotatable and movable. Further, a barrier detecting switch  1   c  having contact pieces  1   d ,  1   e  for detecting the open and close state of the barrier  2  is disposed below the shaft hole  1   i.    
     Further, a small hole  1   h  is disposed at the upper portion of the front face  1   g  of the camera main body  1 . A click spring  1   s  and a click ball  1   r  for applying a click stop action to the barrier  2  are fitted in the small hole  1   h.    
     A later-described barrier lock mechanism comprising the lock shaft  19  (including a mechanism for locking the barrier, a mechanism for preparing the barrier lock, a mechanism for moving a lock member and a mechanism for releasing the barrier lock) is provided at the side portion of the lens barrel  3  in the camera main body  1 . 
     As shown in FIG. 3, the barrier  2  includes engaging guide portions  2   a ,  2   b  located at the upper and lower edge portions of the barrier  2 , and two click recess portions  2   i ,  2   j  located on the inner surface of the upper side. Further, the barrier  2  includes a projection  2   c  on an inner surface  2   e  located near a closing side edge face  2   f , a rib portion  2   k  extending from the lower side of the projection  2   c  in the −X direction (horizontal direction), and a projection  2   d  at the lower portion of the inner surface  2   e.    
     The guide portions  2   a ,  2   b  are freely and slidably fitted in the guide grooves  1   a ,  1   b  of the camera main body  1 , and support the barrier  2  slidably along the guide grooves  1   a ,  1   b.    
     The click ball  1   r , which is placed in the small hole  1   h  at the upper portion of the camera main body  1 , is to fit into the click recess portion  2   i  or  2   j  of the barrier  2 , making a click feeling, and stopping the barrier  2  at a predetermined position. When the ball  1   r  is fitted into the click recess portion  2   i , the barrier  2  is located at the open position P 2 B, and when the ball  1   r  is fitted into the click recess portion  2   j , the barrier  2  is located at the close position P 2 A. 
     When the barrier  2  is located at the open position P 2 B, a projection  2   d  presses the contact piece  1   e  bringing the contact piece  1   e  and the contact piece  1   d  into contact with each other, thereby turning on the barrier detecting switch  1   c . Further, when the barrier  2  is moved from the open position P 2 B, the contact piece  1   e  is released and the barrier detecting switch  1   c  is turned off. In the camera of this embodiment, the barrier detecting switch  1   c  is set to be turned off just when the barrier  2  reaches the semi-open position P 2 C, so as to improve the operational feel. The barrier detecting switch  1   c  is covered by the barrier  2  irrespective of the open or closed position of the barrier  2  and thus the barrier detecting switch  1   c  is not exposed to the outside at any time. The projection  2   c  abuts against the tip portion  19   a  of the lock shaft  19  projecting from the camera main body  1 , and locks the movement of the barrier  2  in the closing direction. The projection  2   c  includes a slant surface  21  which is inclined from the projected portion thereof to the inner surface  2   e  of the barrier  2  in the −X direction. 
     The rib portion  2   k  is a part of the mechanism for preparing the barrier lock. It may press the arm portion tip  19   b  of the lock shaft  19  on the end surface thereof, to rotate the lock shaft  19  in the counterclockwise direction. 
     Next, the arrangement around the lens barrel  3 , the lens barrel driving mechanism and the barrier lock mechanism will be described in detail with reference to FIGS. 4 to  8 , FIGS. 9 to  12  and FIGS. 13 to  17 . 
     FIG. 4 is an exploded perspective view showing the lens barrel driving mechanism and the barrier lock mechanism. FIG. 5 is an exploded perspective view of a part of the barrier lock mechanism taken in the C direction of FIG.  4 . FIG. 6 is a cross-sectional view taken along E—E of FIG.  5 . FIGS. 7A and 7B are cross-sectional views taken along F—F of FIG.  6 . FIG. 7A shows the state of each of an arm-portion tip  19   b  (described later), a driven arm portion  19   c  (described later) and a rotational stop projecting portion  19   d  (described later) of the lock shaft  19  when the barrier  2  is located at the open position P 2 B or semi-open position P 2 C. FIG. 7B shows the state of the arm-portion tip  19   b , the driven arm portion  19   c  and the rotational stop projecting portion  19   d  of the lock shaft  19  when the barrier  2  is located at the closed position P 2 A or during the barrier closing operation. FIG. 8 is a cross-sectional view taken along D—D of FIG.  4 . FIGS. 8A to  8 D show variations of the relative positional relationships between a driving projection  3   g  (described later) and the driven arm portion  19   c  (described later) of the lock shaft  19  when the lens barrel  3  is extracted. FIGS. 9 to  12  are front views of the camera of this embodiment which are viewed in the A direction of FIG. 1, and FIGS. 13 to  17  are cross-sectional views of the camera of this embodiment which is taken along B—B of FIG.  1 . FIGS. 9-17 show the process from the extracted state of the lens barrel  3  to the retracted state of the lens barrels. Within the camera main body  1  serving as the outer shell, and a rear cover  21 , an aperture member  22  having an opening portion for a film is disposed at the rear side of the lens barrel  3  as shown in FIG. 13. A cartridge chamber in which a film cartridge  25  is put is provided at one side of the aperture member  22 , and a spool chamber in which a spool  26  is put is provided at the other side of the aperture member  22 . 
     A pressure plate  23  disposed in the back surface side of the aperture member  22  is pressed by a pressure plate spring  24 . A film  27  fed from the film cartridge  25  is guided to the spool  26  through the feeding path between the aperture member  22  and the pressure plate  23 . An electrical circuit board unit  28  for controlling the camera is disposed in front of the spool  26 . 
     As shown in FIGS. 4, and FIGS. 13-17, the lens barrel  3  has a zoom moving frame  3   f  for holding the photographic lens  3   e , and a moving frame  3   a  which is disposed on the outer periphery of the zoom moving frame  3   f  to support the zoom moving frame  3   f  so that the zoom moving frame  3   f  is forwardly and backwardly movable. The lens barrel  3  is fitted into the opening portion  1   j  of the camera main body  1 , and supported to be freely forwardly and backwardly movable in the Z direction along the optical axis O. The lens barrel  3  is forwardly and backwardly movable between the retracted position (see FIG. 17) at which the lens barrel  3  is retracted in the camera main body  1  and the photographing standby position (or the photographing position, FIGS. 1,  13 ) at which the lens barrel  3  is extracted from the camera main body  1 . 
     In the side portion of the outer periphery of the moving frame  3   a , the following are included: a shaft hole  3   d  in which a guide shaft  15  is freely and slidably fitted, a female screw portion (threaded screw hole)  3   c  with which a feeding screw (shaft)  13  parallel to the guide shaft  15  is threadedly engaged, and a driving projecting portion  3   g  which provide a mechanism for preparing the barrier lock, a mechanism for moving the lock member and a mechanism for releasing the barrier lock. 
     The feeding screw (shaft)  13  and the guide shaft  15  are supported by the camera main body  1  and the aperture member  22 . A gear  14  is fixed to one end of the feeding screw (shaft)  13 . The gear  14  engages a pinion  12  of the output shaft of a driving motor  11 . Consequently, when the driving motor  11  is rotated, the feeding screw (shaft)  13  is also rotated accordingly and the moving frame  3   a  of the lens barrel  3  is forwardly or backwardly driven in the Z direction along the guide shaft  15 . 
     A slit plate  16  is fixed to the output shaft of the driving motor  11 , and the rotational amount of the slit plate  16  is detected by a photointerruptor  17 . The contact piece portions (not shown) of a retracted position detecting switch  34   a  (FIG. 18) and a photographing standby position (or photographing position) detecting switch  34   b  (FIG. 18) are mounted on the moving frame  3   a . The forward/backward movement position of the lens barrel  3 , for example, during the retraction, or when at the photographing position, is detected using a barrel position detecting encoder circuit board (not shown). 
     As shown in FIGS. 4-6, the barrier lock mechanism includes the lock shaft  19 , an urging spring  20 , a bearing portion  1   k , located in the camera main body  1 , the driving projecting portion  3   g  of the lens barrel  3 , the projection  2   c  of the barrier  2  and the rib portion  2   k  of the barrier  2 . The lock shaft  19  serves as the lock member. The urging spring  20 , serves as an urging member and applies tension to the lock shaft  19 . The bearing portion  1   k  provides freely and slidably support to the lock shaft  19 . 
     The bearing portion (shaft receiving portion)  1   k  for supporting the lock shaft  19  of the camera main body  1  is provided on the inner surface of the body adjacent to the shaft hole portion  1   i  on the left side of the lens opening portion  1   j  so as to project in the optical axis O direction. The bearing portion (shaft receiving portion)  1   k  includes a shaft hole  11  in which the tip portion  19   a  of the lock shaft  19  is rotatably inserted, a notch  1   q  which determines the range of the rotational angle of the lock shaft  19  within a predetermined angle (about 90° for this particular embodiment of the invention), and a guide groove  1   p  in which the arm portion of the lock shaft  19  is inserted. The shaft hole  11  communicates with the shaft hole  1   i  disposed in the front surface  1   g  of the camera main body. 
     The lock shaft  19  has an arm portion of bent shape which projects from the tip portion  19   a  in the sideward direction, and the arm portion has an arm-portion tip  19   b  serving as the lock standby start mechanism. The lock shaft  19  is equipped with the rotation stop projecting portion  19   d , and the driven arm portion  19   c  which projects sideward at the rear end side of the lock shaft  19  and constitutes one part of the lock release mechanism and the lock standby start mechanism. 
     The urging spring  20  used for applying urging tension to the lock shaft  19  is a torsion spring which can be expanded and contracted in the axial direction of the coil, and it constitutes one component of the lock standby start mechanism and the lock member moving mechanism. One end of the urging spring  20  is fitted into a spring support projection  22   k  of the aperture member  22 , and the other end is fitted into the side end portion of the driven arm portion  19   c  of the lock shaft  19  and supported. A hook portion  20   b  of the urging spring  20  is suspended on a projection  22   j  of the aperture member  22 , and a hook portion  20   a  is suspended on the driven arm portion  19   c  of the lock shaft  19 . Consequently, the urging spring  20  can urge the lock shaft  19  both in the +Z direction and in the clockwise direction. 
     The lock shaft  19  is fitted in the shaft hole  11  of the bearing portion (shaft receiving portion)  1   k  so as to be rotatable and slidable in the Z direction. The tip portion  19   a  of the lock shaft  19  and the arm-portion tip  19   b  project outwardly from the shaft hole  1   i  of the camera main body  1 . Accordingly, the lock shaft  19  is installed so as to be movable between the lock (fixing) position P 19 B (FIGS. 13,  14 ) and the lock (fixing) release position P 19 A (FIG.  15 ). 
     When the lock shaft  19  is located at the lock position P 19 B, the projecting portion  2   c  of the barrier  2  is able to abut against the tip portion  19   a  of the lock shaft  19 , and the movement of the barrier  2  in the closing direction (+X direction) is prevented. When the lock shaft  19  is retracted at the lock release position P 19 A, the projection  2   c  of the barrier  2  and the tip portion  19   a  of the lock shaft  19  do not interfere with each other and thus the movement of the barrier  2  in the closing direction is allowed. 
     When the lock shaft  19  is located at the lock position P 19 B, the lock shaft  19  is kept in the rotation-limited state while the rotational stop projecting portion  19   d  abuts against the notch  1   q  of the bearing portion  1   k , and the position of the lock shaft  19  in the axial direction is determined because the front end surface of the tip portion  19   a  abuts against the inner (wall) surface  2   e  of the barrier  2 . The positioning of the lock shaft  19  in the Z direction at the lock position P 19 B may be achieved by other means, for example, by making the rotational stop projecting portion  19   d  abut against the bottom portion of the notch  1   q.    
     The driven arm portion  19   c  of the lock shaft  19  is one of the constituent elements of the lock release mechanism. It abuts against the driving projection portion  3   g  of the lens barrel  3  when the lens barrel  3  is retracted and is pressed in the −Z direction, whereby the lock shaft  19  is backwardly moved (retracted) to the lock release position P 19 A. 
     When the lock shaft  19  is located at the lock release position P 19 A, the arm-portion tip  19   b  of the lock shaft  19  is allowed to be pressed by the tip face of the rib portion  2   k  of the barrier  2 . When the arm-portion tip  19   b  of the lock shaft  19  is pressed by the rib portion  2   k , the lock shaft  19  is rotated counterclockwise by substantially 90° (FIG.  7 B). By the counterclockwise rotation of the lock shaft  19 , the engagement between the driven arm portion  19   c  and the driving projection portion  3   g  of the lens barrel  3  is released, and the lock shaft  19  is set to the lock standby state (lock-ready state) (FIGS. 7B,  16 ). The lock standby state of the lock shaft  19  corresponds to a state where the lock shaft  19  is moved in the +Z direction by the urging force of the urging spring  20 , and the tip portion  19   a  of the lock shaft  19  abuts against the inner surface  2   e  of the barrier  2 . Because the lock shaft  19  is kept in the lock standby state under the barrier closed state, when the barrier  2  is moved to the semi-open position P 2 C, the lock shaft  19  further advances and moves to the lock position P 19 B in the +Z direction urged by the urging spring  20 , thereby locking the barrier  2 . 
     When the lock shaft  19  is located at the lock position P 19 B, the arm-portion tip  19   b  is released from the rib portion  2   k  of the barrier  2 . Further, under the state that the lens barrel  3  is retracted, the driven arm portion  19   c  of the lock shaft  19  is located in front of (+Z side) of the driving projection portion  3   g  of the lens barrel  3  as shown in FIG.  8 A. When the lens barrel  3  is extracted from the state of FIG.  8 A, a slant surface  3   h  of the driving projection portion  3   g  and a slant surface  19   e  of the driven arm portion  19   c  abut against each other (FIG.  8 B), and the slant surface  3   h  of the driving projection portion  3   g  and the slant surface  19   e  of the driven arm  19   c  are slid along each other. Through this sliding motion, the driving projection portion  3   g  applies a force to the driven arm portion  19   c  through the slant surface  3   h  opposing the clockwise rotational urging force of the urging spring  20  suspended on the lock shaft  19 , whereby the driving projection portion  3   g  lifts up the driven arm portion  19   c  (FIG. 8C) and the lock shaft  19  is temporarily rotated counterclockwise. Therefore, the driving projection portion  3   g  moves in front of the driven arm portion  19   c  (FIG.  8 D). Thereafter, the photographic lens barrel  3  reaches the photographic standby position. 
     The configuration of a camera lens barrel controller serving as the driving control mechanism employing this embodiment of the present invention and a main electrical control circuit around each detecting switch portion will be described with reference to the electrical circuit diagram of FIG.  18 . 
     The electrical control circuit of the camera employing this embodiment is powered by a battery  31  serving as a power source. A Central Processing Unit (CPU)  32  controls operation of the electrical control circuitry of the camera. A driver  33  drives the driving motor  11  and is controlled by CPU  32 . The driving motor  11  moves the lens barrel  3  forwardly and backwardly. 
     CPU  32  may receive an ON-signal from the barrier detecting switch  1   c  detecting that the barrier  2  is open, and then starts the extraction of the lens barrel  3 . CPU  32  may receive an OFF-signal from the barrier detecting switch  1   c  detecting the start of the closing operation of the barrier  2 , and then starts the retraction of the lens barrel  3 . CPU  32  receives the output signals from the retracted position detecting switch  34   a  and the photographing standby position (photographic position) detecting switch  34   b  installed in the camera main body  1  and detects the forward or backward movement (advance/retraction) state of the lens barrel  3 . Further, when the lens barrel  3  is located at the photographic standby position, and CPU  32  receives the output signal from the release switch  10   a  driven by the release button  10 , CPU  32  starts the sequence for the photographing operation. 
     Next, the forward and backward moving operations (advance/retraction operation) of the lens barrel  3  in connection with the barrier opening and closing operation of the camera of the embodiment will be described with reference to the front views of the camera in FIGS. 9 to  12  and the cross-sectional views of the camera in FIGS. 13 to  17 . FIGS. 9 and 13 show the state in which the lens barrel  3  is extracted to the photographic standby position and the barrier  2  is in the open state. FIGS. 10 and 14 show the state in which the barrier  2  is in the semi-open position and the lens barrel  3  has just started to move from the photographic standby position to the retracted position. FIG. 15 shows the state in which the barrier  2  is a semi-open position and the retracting operation of the lens barrel  3  has completed. FIGS. 11 and 16 show the state that the barrier  2  is further moved in the closing direction from the semi-open position after the lens barrel  3  has retracted to the retracted position. FIGS. 12 and 17 shows the state that the barrier  2  has moved to the closed position and the lens barrel  3  has been located at the retracted position. 
     When the camera is in the non-photographic state, the lens barrel  3  is positioned in the retracted position as shown in FIGS. 12 and 17, and the lens barrel  3  has retreated from the moving path of the barrier  2 . Further, the barrier  2  is located at the closed position P 2 A and the front face of the lens barrel  3  is completely covered by the barrier  2 . 
     When the barrier  2  is located at the closed position P 2 A, the lock shaft  19  is set to the rotated state such that the arm-portion tip  19   b  abuts against the upper surface of the rib portion  2   k  of the barrier  2  as shown in FIG.  7 B. Under this state, the driven arm portion  19   c  is released from the abutting state under which it abuts against the driving projection portion  3   g  of the lens barrel  3 , and the tip portion  19   a  is held in the lock standby state (engaging standby state) under which the tip portion  19   a  abuts against the inner surface  2   e  of the barrier  2 . 
     In order to set the camera from the non-photographic state shown in FIGS. 12,  17  to the photographic standby state shown in FIGS. 9,  13 , the barrier  2  is manually slid in the −X direction so that it passes over the semi-open position P 2 C at which it is retreated from the front face of the photographic lens  3   e  and reaches the open position P 2 B. Both the semi-open position P 2 C and the open position P 2 B are within the range of the retreated position in which the barrier  2  has retreated enough so as not to disturb the extraction of the photographic lens  3   e.    
     During the movement of the barrier  2  in the open direction, the tip portion  19   a  of the lock shaft  19 , which is in the lock standby state, is slid on the inner surface  2   e  of the barrier  2  while it is pressed on the surface by the urging force of the urging spring  20 . When the barrier  2  reaches at the semi-open position P 2 C or passes the position, after the tip portion  19   a  of the lock shaft  19  has passed over the slant surface  21  of the projection  2   c , the tip portion  19   a  of the lock shaft  19  under the lock standby state just jumps to the +X (right) side of the projection  2   c  to locate in the lock position P 19 B (FIGS. 7A,  13 ,  14 ). At this time point, the lock shaft  19  is set to the lock state (locking state) under which it fixes the barrier  2 . The lens barrel  3  has still been kept at the retracted position of FIG.  17 . In this state, the barrier  2  is located outside of the moving path of the lens barrel  3 , and the lens barrel  3  is ready to be extracted. Since the lock shaft  19  is located at the lock position P 19 B, the barrier  2  is prevented from being moved in the closing direction by the tip portion  19   a  of the lock shaft  19 . 
     When the lock shaft  19  is moved to the lock position P 19 B under the state where the barrier  2  is located at the semi-open position P 2 C, the arm-portion tip  19   b  of the lock shaft  19  is also released from the rib portion  2   k  of the barrier  2 , so that the lock shaft  19  is clockwise rotated by the urging force of the urging spring  20 , and the driven arm portion  19   c  is set to be located at the +Z side of the driving projection portion  3   g  of the lens barrel  3  (FIG.  8 A). 
     When the barrier  2  is moved to the open position P 2 B, the output of the barrier detecting switch  1   c  is switched on by the barrier projection  2   d  (FIG.  9 ). The ON-signal is input to CPU  32 , and the driving motor  11  is driven under the control of CPU  32 , so that the lens barrel  3  starts its extraction to the photographic standby position. When the lens barrel  3  is extracted, the lens barrel  3  is located within the moving path of the barrier  2 . 
     In this embodiment, the barrier  2  is locked at the semi-open position P 2 C, and then the extraction of the lens barrel  3  is started when the barrier  2  is at the open position. However, as long as the barrier  2  is located in the range of the retreated position, the position at which the barrier  2  is locked can be set to be the same position at which the extraction of the lens barrel  3  is started. However, if these positions are different from each other as in the case of the above-described embodiment, the extraction of the lens barrel  3  is started after the lock of the barrier  2  has been surely finished, and thus this embodiment is more advantageous in operation stability. 
     During the extracting operation of the lens barrel  3 , the driving projection portion  3   g  of the lens barrel  3  changes its positional order to the driven arm portion  19   c  (moves to the front of the driven arm portion  19   c  from behind it) and thus locates in front of the driven arm portion  19   c  by pushing aside the driven arm portion  19   c  of the lock shaft  19  located in the front side of the driving projection portion  3   g  (+Z side). 
     Even if the barrier  2  is carelessly pushed in the closing direction during the extraction of the lens barrel  3 , the barrier  2  cannot be moved from the semi-open position P 2 C in the closing direction because the lock shaft  19  has been moved to the lock position P 19 B as described above, and thus the lens barrel  3  is protected from the barrier  2 . 
     When the lens barrel  3  is to be retracted and set to the non-photographing state, after the photographing operation state shown in FIGS. 9,  13  is over, the barrier  2  is manually slid in the +X direction by a slight amount as shown in FIGS. 10,  14  which switch the barrier detecting switch  1   c  to the OFF-state. At this time, the barrier  2  is locked at the semi-open position P 2 C by the tip portion  19   a  of the lock shaft  19  located at the lock position P 19 B (FIG.  7 A). Consequently, the barrier  2  is kept out of the moving path of the lens barrel  3 , and the closing side end face  2   f  of the barrier  2  is not brought into contact with the lens barrel  3 . 
     The projection  2   d  of the barrier  2  is separated and released from the contact piece  1   e  of the barrier detecting switch  1   c  through the closing movement of the barrier  2 , so that CPU  32  receives the off-signal from the barrier detecting switch  1   c . By this signal, CPU  32  controls the driving of the driving motor  11  to start the retracting operation of the lens barrel  3  in the retraction direction. This embodiment is designed so that the barrier detecting switch  1   c  is switched off as soon as the barrier  2  is moved to the semi-open position P 2 C thus enhancing operational and providing a smooth feeling. 
     The driving projection portion  3   g  of the lens barrel  3  comes into contact with the driven arm portion  19   c  of the lock shaft  19  and presses the driven arm portion  19   c  in the −Z direction around the end of the retraction operation of the lens barrel  3 . This pressing movement releases the engaging between the tip portion  19   a  of the lock shaft  19  and the projection  2   c  of the barrier  2 , and the lock shaft  19  is moved to the lock release position P 19 A (FIG.  15 ). At this time, the lock shaft  19  is set to the non-lock state (non-fixed state) under which the locking of the barrier  2  is forcibly released, whereby the barrier  2  is allowed to be moved in the closing direction. At this time, the lens barrel  3  arrives at the retraction position (FIG.  15 ). 
     The arrival of the lens barrel  3  at the retraction position causes the retraction position detecting switch  34   a  to output an ON-signal. The ON-signal output from the retraction position detecting switch  34   a  is input as a retraction position arrival signal at CPU  32 , so that the retraction of the lens barrel  3  is stopped and CPU  32  is set to the stopped state. 
     When the lens barrier is retracted to the retraction position, it is located out of the moving path of the barrier  2 . Since the lock shaft  19  is located at the lock release position P 19 A, the barrier  2  is able to be manually slid from the semi-open position P 2 C to the closed position P 2 A in the +X direction. However, even when this sliding motion is carried out, the barrier  2  does not interfere with the lens barrel  3 . 
     When the barrier  2  is being closed from the semi-open position P 2 C in the closing direction, the arm-portion tip  19   b  of the lock shaft  19  is pressed by the end face of the rib portion  2   k  of the barrier  2  with the above closing operation, and the lock shaft  19  is counterclockwise rotated against the rotational urging force of the urging spring  20  (FIG. 7B or FIGS. 11,  16 ). Since the engagement between the driven arm portion  19   c  and the driving projection portion  3   g  of the lens barrel  3  is released through the rotation of the lock shaft  19 , the lock shaft  19  is set to the lock standby state (engagement standby state) in which the lock shaft  19  is urged in the +Z direction by the urging force along the axial direction. In this case, the tip portion  19   a  of the lock shaft  19  abuts against the projection  2   c  of the barrier  2  or the inner surface  2   e  of the barrier  2  in the neighborhood of the −Z side of the projection  2   c  (FIG.  16 ). 
     During the subsequent movement of the barrier  2  to the closed position P 2 A, the arm-portion tip  19   b  of the lock shaft  19  is sliding along the upper surface of the rib portion  2   k  of the barrier  2  (FIG.  7 B), and the lock standby state of the lock shaft  19  is unchanged. Further, during the movement of the barrier  2  to the close position P 2 A, the tip portion  19   a  of the lock shaft  19  is slid on the inner surface  2   e  of the barrier  2 . 
     When the barrier  2  reaches the closed position P 2 A, the front face of the lens barrel  3  is covered by the barrier  2  and the camera is set to the non-photographing state. Thereafter, to set the camera in the photographing standby state again, the barrier  2  is slid in the opening direction and the extraction of the lens barrel  3  shown in FIGS. 9,  13 , etc. is executed. 
     Next, the photographic processing control operation which includes the lens barrel driving control in connection with the opening or closing operation, will be described with reference to the flowchart of FIG.  19 . 
     FIG. 19 is a general flowchart showing the photographic processing including the photographic lens barrel driving control in connection with the opening or closing operation of the barrier of the camera according to this embodiment of the present invention. 
     When the barrier  2  is manually moved from the closed state to the open position P 2 B, the contact pieces  1   d ,  1   e  of the barrier detecting switch  1   c  are brought into contact with each other which turns on the barrier detecting switch  1   c . The lens barrel driving operation and the photographic processing under the control of CPU  32  shown in FIG. 18 are started on the basis of the ON-signal output from the barrier detecting switch  1   c.    
     In step S1, CPU  32  transmits a driving signal to the motor driver  33 , and the photographic lens barrel  3 , which has been retracted in the camera is extracted to the photographic standby position (photographic position) by the driving motor  11 . In step S2, CPU  32  checks whether the lens barrel  3  is located at the photographic standby position (lens initial position), for example, it arrives at a zoom wide end position. When the photographing standby position detecting switch  34   b  detects that the lens barrel  3  has arrived at the photographic standby position, the driving motor  11  is turned off in step S3 to stop the extraction of the lens barrel  3 . 
     Thereafter, the processing goes to step S4 and the release switch  1   a  checks whether the release button  10  is being operated. When the switch  10   a  is turned on, the processing goes to step S5 and the photographic sequence processing of CPU  32  is executed. 
     When it is detected by the check of the step S4 that the release switch  10   a  is turned off, the processing jumps to step S6 to check whether the barrier detecting switch  1   c  of the barrier  2  is turned on or off. If it is detected that the barrier detection switch  1   c  is turned off (that is, when the barrier  2  is manually moved in the close direction), the processing goes to step S7 to drive the lens barrel  3  in the retracting direction (−Z direction). 
     In step S8, it is checked on the basis of the output signal of the retraction position detecting switch  34   a  whether the lens barrel  3  has reached the retraction position. If it is judged that the lens barrel  3  has arrived at the retraction position, the processing goes to step S9 to stop the driving of the lens barrel  3 , and this routine is finished. 
     According to the camera of this embodiment of the present invention, during the retraction operation of the lens barrel  3  to the retraction portion or when the lens barrel  3  is extracted to the photographic standby position, the barrier  2  is locked at the semi-open position P 2 C by the lock shaft  19  located at the lock position P 19 B. Therefore, even when the barrier  2  is pressed in the closing direction (+X direction), the barrier  2  will not abut against the lens barrel  3 . 
     Particularly in the camera of this embodiment of the present invention, when the camera is under the non-photographic state, the lock shaft  19  has been already set to the lock (fix) standby state. Consequently, in the case where the barrier  2  is moved from the closed position P 2 A in the open direction in order to switch the camera from the non-photographic state to the photographic state (photographic standby state), the lock shaft  19  is moved from the lock standby state to the lock (fix) position P 19 B immediately after the barrier  2  arrives at the semi-open position P 2 C. Immediately after that, the barrier  2  is surely locked (fixed) at the semi-open position P 2 C by the lock shaft  19  even when the barrier  2  is carelessly pushed in the closing direction. Consequently, the contact between the lens barrier and the lens barrel just after the open operation of the barrier by unintentionally pushing the barrier, as happened in the prior art shown in FIG. 20, can be effectively prevented. 
     As described above, according to the present invention, in a camera having a lens barrier which can be opened and closed in front of a moveable lens barrel, damages of the lens barrel or a mechanism for driving the lens barrel caused by unintentional operation of the barrier are effectively decreased.

Technology Category: 3