Abstract:
A device for use in a camera system including a camera, an optical characteristics modifying converter, and an optical assembly having an image stabilizing unit for stabilizing an image in response to the output of a vibration sensor for detecting a shake in an apparatus includes activating means for activating the stabilization operation by the image stabilizing unit in response to a predetermined operation in a predetermined operation portion of the camera, a determining means for determining whether an optical characteristics modifying converter without image stabilization function is incorporated in the camera system, and decision means for deciding whether to perform an activating operation by the activating means based on a determination by the determining means. The operation of a image stabilizing unit is determined by the incorporation of the converter.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a device for use in a camera system which includes an optical assembly having an image stabilizing unit for correcting image blur caused by shake in a camera or other optical apparatus. 
     2. Description of the Related Art 
     In cameras today, important settings including exposure and focus settings are all automated and even a person not familiar with camera operation is unlikely to fail to take a photograph. 
     Systems for preventing camera shake have been studied, and there are almost no factors that could cause a photographer to abort photographing. 
     Now a system for preventing camera shake is briefly discussed. 
     Camera shake during photographing is due to vibrations whose frequency falls within a range of 1 to 12 Hz. In order to photograph in image-blur free fashion even with camera shake at the moment of a shutter release, camera shake is detected and then a correction lens is displaced in response to the detected shake. To take a picture image-blur free, the camera shake needs to be accurately detected and variations in the optical axis of the camera need to be corrected accordingly. 
     Theoretically speaking, the vibration of a camera (camera-shake) is detected using vibration sensor means for detecting angular acceleration, angular velocity, angular displacement, the like, and camera shake sensor means that outputs angular displacement by electrically or mechanically integrating an output signal of the vibration sensor means. Image blur is thus, prevented by driving a correction optical system that decenters the optical axis of a photograph based on the information from these sensor mean. 
     The stabilization system using such vibration sensor means is now discussed referring to FIG.  8 . 
     FIG. 8 shows the system for controlling image blur resulting from the vertical component  81   p  and horizontal component  81   y  of camera shake represented by arrows  81 . 
     Shown in FIG. 8 are a lens barrel  82 , and vibration sensor means  83   p  and  83   y  for detecting respectively the vertical component and horizontal component of the camera vibration;  84   p  and  84   y  denote respectively the directions of vibration. A correction optical assembly  85  (including coils  87   p ,  87   y  for imparting thrust to the correction optical assembly  85  and position sensors  86   p ,  86   y  for sensing the position of the correction optical assembly  85 ) is provided with a position control loop to be described later, and is driven with its target set to the output of the vibration sensor means  83   p ,  83   y , thereby stabilizing an image on an image plane  88 . 
     FIG. 9 is an exploded perspective view of an image stabilizing system (constructed of the vibration sensor means, the correction optical assembly, the coils, the position sensors and a variety of ICs) preferably used for the above purpose, and referring to FIGS. 9 through 18, the construction of the assembly is now discussed. 
     Rear projections  71   a  (one of three projections  71  not shown) of a base plate  71  (see its enlarged view in FIG. 12) are engaged with the lens barrel, and known barrel rollers are screwed into holes  71   b  to be secured to the lens barrel. 
     A glossily plated second yoke  72  of a magnetic material is secured to the base plate  71  by screws that pass through holes  72   a  of the yoke  72  and are screwed into screw holes  71   c  of the base plate  71 . Permanent magnets (for shifting)  73  of neodymium or the like are magnetically attached to the second yoke  72 . The direction of magnetization of each permanent magnet  73  is represented by an arrow  73   a  as shown in FIG.  8 . 
     A correction lens  74  is attached with a C ring to a support frame  75  (shown in an enlarged view in FIG.  13 ). Coils  76   p ,  76   y  (shift coils) are forced to snap into place with the support frame  75  (the coils are not yet snapped in FIG.  13 ). Light emission devices (IRED)  77   p ,  77   y  are glued onto the rear surface of the support frame  75 . Light rays emitted therefrom pass through slits  75   ap ,  75   ay  and reach position sensor devices (PSD)  78   p ,  78   y.    
     Each of holes  75   b  (at three positions) of the support frame  75  receives pins  79   a ,  79   b , each having a spherical end and made of POM (polyacetal resin), and a bias spring  710  (as shown in FIGS.  10  and  12 ). The pin  79   a  is thermally caulked to the support frame  75  (the pin  79   b  is slidable in the direction of the hole  75   b  against the urging of the bias spring  710 ). 
     FIG. 10 is a cross-sectional view showing the image stabilizing system after it is assembled. The pin  79   b , the bias spring  710 , and the pin  79   a  in that order are inserted into the hole  75   b  of the support frame  75  in the direction of an arrow  79   c  (pins  79   a ,  79   b  are identical in shape), and the circular end portion  75   c  of the hole  75   b  is thermally caulked to prevent the pin  79   a  from coming off. 
     FIG. 11A is a cross-sectional view of the hole  75   b  viewed perpendicular to the page of FIG. 10, and FIG. 11B is a front view of the hole  75   b  viewed from the direction shown by the arrow  79   c  in FIG.  11 A. Reference characters A through D in FIG. 11B correspond to depths A through D in FIG.  11 A. 
     The back end of a blade portion  79   aa  of the pin  79   a  is engaged with and restrained by a surface A, and the circular end  75   a  is caulked, and the pin  79   a  is secured to the support frame  75 . 
     Since a blade portion  79   ba  of the pin  79   b  is engaged with an abutment surface B, the pin  79   b  is prevented from coming out of the hole  75   b  under the urging of the bias spring  710 . 
     When image stabilizing system is fully assembled, the pin  79   b  is engaged with the second yoke  72 , and is thus prevented from coming out of the support frame  75 . For convenience of assembling, the abutment surface B for locking purpose is provided. 
     As FIGS. 10 and 11 show the shapes of the support frame  75  and the holes  75   b , the support frame  75  is manufactured using a simple split type molding technique in which a mold is simply pulled out in the direction of the arrow  79   c,  rather than a complex inner diameter slide molding technique, and accommodates high dimensional accuracy requirements. 
     The use of the pins  79   a ,  79   b , identical to each other, reduces component cost, promotes error free assembling, and is advantageous from the component management point of view. 
     A shaft socket  75   d  of the support frame  75  is coated with fluorine-based grease, and receives one end of an L-shaped shaft  711  (non-magnetic stainless steel) (see FIG.  9 ). The other end of the L-shaped shaft  711  is received in a shaft socket  71   d  (similarly coated with the grease) formed in the base plate  71 . With the three pins  79   b  resting on the second yoke  72 , the support frame  75  is seated in the base plate  71 . 
     As shown in FIG. 9, pins  71   f  (at three points) of the base plate  71  shown in FIG. 12 are received in alignment holes (at three points)  712   a  of a first yoke  712  shown in FIG. 9 while the first yoke  712  is engaged with abutment surfaces  71   e  (at five points) shown in FIG. 12 to be magnetically coupled to the base plate  71  (by means of magnetic force of the permanent magnets  73 ). 
     In this way the rear surface of the first yoke  712  is put into contact with the pins  79   a , and the support frame  75  is interposed between the first yoke  712  and the second yoke  72  as shown in FIG. 10 so that the support frame  75  is registered in the direction of the optical axis of the camera. 
     The abutment surfaces of the first yoke  712  and the second yoke  72  and of the pins  79   a ,  79   b  mutually in contact are coated with fluorine-based grease, and the support frame  75  is slidably moved relative to the base plate  71  in a plane perpendicular to the optical axis. 
     The L-shaped shaft  711  permits the support frame  75  to be slidably supported relative to the base plate  71  in the directions shown by the arrows  713   p ,  713   y  only, thereby restraining a relative rotation (rolling) of the support frame  75  around the optical axis relative to the base plate  71 . 
     The looseness permitted between the L-shaped shaft  711  and the shaft sockets  71   d ,  75   d  are set to be large in the direction of the optical axis so that the shaft sockets  71   d ,  75   d  may not override the restraint in the direction of the optical axis on the support frame  75  provided by the pins  79   a ,  79   b  interposed between the first yoke  712  and second yoke  72 . 
     The first yoke  712  is covered with an insulating sheet  714 . Mounted on the insulating sheet covered yoke  712  is a hard circuit board  715  (bearing the position sensor devices  78   p ,  78   y,  an amplifier IC, driving ICs for coils  76   p ,  76   y ) with its alignment holes  715   b  allowing pins  71   h  (at two points) of the base plate  71  to pass therethrough. At the same time, holes  715   b  of the circuit board  715  and holes  712   b  of the first yoke  712  are aligned and secured with holes  71   g  of the base plate  71  with screws. 
     The position sensors  78   p ,  78   y  are soldered to the hard circuit board  715  with the sensors aligned on the hard circuit board  715  with an instrument, and a flexible circuit board  716  is thermally bonded to the hard circuit board  715  with the surface  716   a  of the board  716  interfaced to the area  715   c  (see FIG. 9) of the rear side of the hard circuit board  715 . 
     A pair of arms  716   bp ,  716   by  are extended from the flexible circuit board  716  in a plane perpendicular to the optical axis, and are engaged with lock portions  75   eb ,  75   ey  (see FIG. 13) of the support frame  75 , and the terminals of the light emission devices  77   p ,  77   y  and the terminals of coils  76   p ,  76   y  are soldered to them. 
     The light emission devices  77   p ,  77   y  of IRED and coils  76   p ,  76   y  are driven by the hard circuit board  715  via the flexible circuit board  716 . 
     The arms  716   bp ,  716   by  (FIG. 9) of the flexible circuit board  716  have respectively bent portions  716   cp ,  716   cy . With their elasticity, the bent portions  716   cp ,  716   cy  lessen the load imposed on the arms  716   bp ,  716   by  when the support frame  75  moves in a plane perpendicular to the optical axis. 
     The first yoke  712  has elevated faces  712   c  formed through die cutting. The elevated faces  712   c  are directly put into contact with the hard circuit board  715  through notches  714   a  of the insulating sheet  714 . The hard circuit board  715  has a ground trace on its surface in contact with the elevated faces  712   c.  By connecting the hard circuit board  715  to the base plate with screws, the first yoke  712  is grounded and is prevented from serving as an antenna which could pick up noise for the hard circuit board  715 . 
     The mask  717  shown in FIG. 9 is aligned relative to the base plate  71  by pins  71   h , and is affixed to the hard circuit board  715  using two-sided adhesive tape. 
     The base plate  71  is provided with a cutout  71   i  for a permanent magnet (see FIGS.  9  and  12 ), and the rear surface of the second yoke  72  is seen through the cutout  71   i.  A permanent magnet  718  (for locking) is assembled through the cutout  71   i , and is magnetically coupled with the second yoke  72  (FIG.  10 ). 
     A coil  720  (for locking) is glued onto a lock ring  719  (see FIGS. 9,  10  and  14 ). The lock ring  719  has a lug  719   a , the rear surface of which is provided with a bearing  719   b  (see FIG.  15 ). An armature pin  721  (see FIGS. 9 and 15) is inserted into an armature rubber bushing  722  and then inserted through the bearing  719   b , an armature spring  723 , and finally into an armature  724 . The armature pin  721  is caulked to the armature  724 . 
     The armature  724  is slidably moved relative to the lock ring  719  in the direction of an arrow  725  against the urging of the armature spring  723 . 
     FIG. 15 is a view of the image stabilizing system viewed from behind in FIG.  9 . As shown, the lock ring  719  is connected to the base plate  71  in a bayonet-mounting method, in which the lock ring  719  is pushed into the base plate  71  with the outer-circumferential notches  719   c  (at three points) of the lock ring  719  aligned with the inner-circumference projections  71   g  (at three points) and is then turned clockwise to lock into place. 
     The lock ring  719  is rotatable around the optical axis relative to the base plate  71 . A rubber lock  726  is pressed into the base plate  71  (see FIGS. 9 and 15) in order to prevent the bayonet mount from being unlocked with the notches  719   c  of the lock ring  719  meeting the projections  71   j . The lock ring  719  is thus permitted to rotate by an angle of θ until a notch  719   d  is restrained by the rubber lock  726  (see FIG.  15 ). 
     The permanent magnet  718  (for locking) is attached to a locking yoke  727  made of a magnetic material (FIG.  9 ). The locking yoke  727  is attached to the base plate  71  with holes  727   a  (at two points) of the locking yoke  727  receiving pins  71   k  of the base plate  71  and with holes  727   b  (at two points) aligned with  71   n  (at two points) with screws. 
     The permanent magnet  718  on the base plate  71 , the permanent magnet  718  on the locking yoke  727 , the second yoke  72  and locking yoke  727  form a known closed magnetic path. 
     The rubber lock  726  is prevented from coming off because the locking yoke  727  is affixed by screws. For convenience of explanation, the locking yoke  727  is not shown in FIG.  15 . 
     A lock spring  728  is extended between a hook  719   e  of the lock ring  719  and a hook  71   m  of the base plate  71  (FIG. 15) in order to urge clockwise the lock ring  719 . An attracting coil  730  is loaded on an attracting yoke  729  (FIGS.  9  and  15 ). The attracting yoke  729  is secured to the base plate  71  at a hole  729   a  with a screw. 
     The terminals of the coil  720  and the attracting coil  730  may be four wires in twisted pair with Tetoron covering and are soldered to the cores  716   d  of the flexible circuit board  716 . 
     ICs  731   p ,  731   y  (FIG. 9) on the hard circuit board  715  are amplifier ICs for amplifying the outputs of position sensor output terminals  78   p ,  78   y . Their circuits are shown in FIG. 16 (the circuit of IC  731   p  only is shown here because both ICs  731   p ,  731   y  are identical). 
     Referring to FIG. 16, current-voltage converter amplifiers  731   ap ,  731   bp  convert, into voltages, currents  78   i   1   p ,  78   i   2   p  in position sensor  78   p  (including resistors R 1 , R 2 ) generated by the light emission device  77   p , and a differential amplifier  731   cp  determines and amplifies a differential between the outputs of the current-voltage converter amplifiers  731   ap ,  731   bp.    
     The light rays from the light emission devices  77   p ,  77   y  are directed to the position sensor devices  78   p ,  78   y  via slits  75   ap ,  75   ay , respectively. When the support frame  75  moves in a plane perpendicular to the optical axis, the incident positions of the light rays to the position sensor devices  78   p ,  78   y  change. 
     The position sensor device  78   p  has a gain directivity in the direction of an arrow  78   ap  (FIG.  9 ), while the slit  75   ap  is shaped to diverge the light ray in the direction perpendicular to the arrow  78   ap  (namely in the direction of  78   ay ) and to converge the light ray in the direction of the arrow  78   ap . Only when the support frame  75  moves in the direction of an arrow  713   p , the balance between the currents  78   i   1   p,    78   i   2   p  in the position sensor device  78   p  changes causing the differential amplifier  731   cp  to give an output according to the movement of the support frame  75  in the direction of the arrow  713   p.    
     The position sensor device  78   y  had a gain directivity in the direction of an arrow  78   ay  (FIG.  9 ), while the slit  75   ay  is shaped to diverge the light ray in the direction perpendicular to the arrow  78   ay  (namely in the direction of  78   ap ). The output of the position sensor device  78   y  changes its output only when the support frame  75  moves in the direction of an arrow  713   y.    
     A summing amplifier  731   dp  sums the outputs of the current-voltage converter amplifiers  731   ap ,  731   bp  (sum of the amounts of light received by the position sensor device  78   p ), and a driving amplifier  731   ep  drives the light emission device  77   p  in response to the sum signal. 
     The light emission device  77   p  changes its output light level in an extremely unstable manner due to temperature change and the like, and along with such changes, the absolute amount ( 78   i   1   p + 78   i   2   p ) of the currents  78   i   1   p,    78   i   2   p  of the position sensor device  78   p  varies. 
     For this reason, the output of the differential amplifier  731   cp  indicating the position of the support frame  75  ( 78   i   1   p − 78   i   2   p ) also varies. 
     When the driving circuit controls the light emission device  77   p  so that the sum of the amount of light received is constant, no variations take place in the output of the differential amplifier  731   cp.    
     The coils  76   p ,  76   y  shown in FIG. 9 are located in the closed magnetic path formed of the first yoke  712  and second yoke  72 . By causing a current to flow through the coil  76   p , the support frame  75  is driven in the direction of the arrow  713   p  (under Flemming&#39;s rule), and by causing a current to flow through the coil  76   y , the support frame  75  is driven in the direction of the arrow  713   y.    
     The outputs of the position sensor devices  78   p ,  78   y  are amplified by ICs  731   p ,  731   y , and the outputs of ICs  731   p ,  731   y  are used to drive the coils  76   p ,  76   y . The support frame  75  is thus driven, changing the outputs of the position sensor devices  78   p ,  78   y.    
     If the direction of driving (polarity) of the coils  76   p ,  76   y  is set such that the outputs of the position sensor devices  78   p ,  78   y  gets smaller (negative feedback), the support frame  75  is stabilized when the outputs of the position sensor devices  78   p ,  78   y  driven by the coils  76   p ,  76   y  are almost zero. 
     A driving method in which a position sensor output is supplied in a negative feedback loop is called position control method. When a target value (for example, a shake angle signal) is input to ICs  731   p ,  731   y  from outside, the support frame  75  is faithfully driven toward the target value. 
     In an actual circuit arrangement, the outputs of the differential amplifiers  731   cp ,  731   cy  are sent to an unshown main circuit board via the flexible circuit board  716 , and the outputs are analog-to-digital (A/D) converted there and then fed to a microcomputer. 
     In the microcomputer, the A/D converted signal is compared to a target value (shake angle signal), amplified and is subjected to phase lead compensation (for stabilizing position control) using a known digital filtering technique, transmitted through the flexible circuit board  716  to IC  732  (for driving the coils  76   p ,  76   y ). Based on the input signal, IC  732  drives the coils  76   p ,  76   y  in a known PWM method (Pulse Width Modulation), thereby driving the support frame  75 . 
     The support frame  75  is slidably movable in the directions shown by the arrows  713   p ,  713   y  as already described, and stabilizes the camera through position control method. In consumer optical apparatuses such as cameras, however, the support frame  75  cannot be continuously controlled from the standpoint of power saving. With the camera left in no-control state, however, the support frame  75  is free to move in a plane perpendicular to the optical axis, and some preventive step has to be devised against an impact sound or even damage which may be generated when the support frame  75  (its mechanical end, more specifically the end of the lock ring) reaches its stroke limit. 
     A lock mechanism for locking the support frame  75  as such a preventive step is incorporated as described below. 
     Referring to FIGS.  15  and  17 (A and B) the support frame  75  has, on its rear side, three radially extended projections  75   f , and the ends of the projections  75   f  are engaged with the inner circumference  719   g  of the lock ring  719 . The support frame  75  is thus restrained by the base plate  71  in all directions. 
     FIGS. 17A and 17B are rear views showing the working relationship of the lock ring  719  and support frame  75 , and show major portions extracted from FIG.  15 . For convenience of explanation, FIGS. 17A and 17B are drawn slightly differently from their actually assembled state. Cam sections  719   f  (at three points) shown in FIG. 17A are not fully longitudinally extended along the inner circumference of the lock ring  719  as shown in FIGS. 10 and 14, though they are not seen in FIG.  15 . 
     As shown in FIG. 10, the coil  720  is located in the magnetic path between the permanent magnets  718 , and by causing a current to flow through the coil  720 , a torque is generated to rotate the lock ring  719  around the optical axis (twisted lead wires  720   a  shown in FIGS. 17A and 17B are connected at terminals  719   h  to an unshown flexible circuit board that is routed around the outer circumference of the lock ring  719  and connected to terminals  716   e  of the cores  716   d  of the flexible circuit board  716 ). 
     To drive the coil  720 , an unshown microcomputer issues a command to a driver IC  733  on the hard circuit board  715  via the flexible circuit board  716  for control. IC  733  drives the coil  720  in PWM method. 
     Referring to FIG. 17A, the coil  720  is wound such that the coil  720 , when energized, generates a torque for causing the lock ring  719  to rotate counterclockwise. The lock ring  719  thus rotates counterclockwise against the urging of the lock spring  728 . 
     Before being energized, the lock ring  719 , urged by the lock spring  728 , remains stably in contact with the rubber lock  726 . 
     When the lock ring  719  rotates, the armature  724  is put into contact with the attracting yoke  729  compressing the armature spring  723 , thereby equalizing the attracting yoke  729  and the armature  724  in position. The lock ring  719  stops rotating as shown in FIG.  17 B. 
     FIG. 18 is a timing diagram for lock ring driving. 
     The attracting coil  730  is also energized ( 730   a ) at the moment the coil  720  is energized (PWM-driven as indicated  720   b ) at an arrow  719   i  as shown in FIG.  18 . When the armature  724  is in contact with and equalized with the attracting yoke  729 , the armature  724  is attracted by the attracting yoke  729 . 
     When the supply of power to the coil  720  stops at time  720   c  as shown in FIG. 18, the lock ring  719  attempts to rotate clockwise under the urging of the lock spring  728 . The rotation of the lock ring  719  is restrained because the armature  724  is attracted by the attracting yoke  729 . Since the projections  75   f  of the support frame  75  face the respective cam sections  719   f  (the cam sections  719   f  draw near in rotation), the support frame  75  is free to move within the clearance permitted between the projections  75   f  and the cam sections  719   f.    
     Although the support frame  75  is subject to gravity G (see FIG.  17 B), the support frame  75  is prevented from falling because it is also controlled at time  719   i  in FIG.  18 . 
     The support frame  75  is restrained by the inner circumference of the lock ring  719  during no-control state, but there remains a looseness corresponding to fit looseness between the projections  75   f  and the inner circumference  719   g.  The support frame  75  falls in the direction of gravity G by the looseness, and is thereby offset from the center of the base plate  71 . For this reason, the support frame  75  is slowly shifted back to be in alignment with the center of the base plate  71  (center of the optical axis) from time  719   i , for example, taking one second. 
     This quick shifting of the support frame  75  to the center causes image motion, which a photographer finds uncomfortable when it is seen through the correction lens  74 . Furthermore, degradation resulting from the shifting of the support frame  75  is precluded even if an exposure is performed during the shifting. (For example, the support frame  75  is shifted by 5 μm for ⅛ second.) 
     More particularly, the outputs of the position sensor devices  78   p ,  78   y  are stored at time  719   i  shown in FIG. 18, control of the support frame  75  starts with the outputs set as a target value, and for a duration of one second, the support frame  75  is shifted toward the target value of the center of the optical axis that is set beforehand (refer to  75   g  in FIG.  18 ). 
     After the lock ring  719  is rotated (in unlock state), the support frame  75  is driven based on a target value from vibration sensor means (along with the movement of the support frame  75  back to the center), and stabilization operation thus starts. 
     To end the stabilization, image stabilization is set to be off at time  719   j , the target value from the vibration sensor is not fed to correction driving means for driving correction means, and the support frame  75  is controlled so as to move to its centered position. The supply of power to the attracting coil  730  stops ( 730   b ). Since the attracting force of the yoke  729  for attracting the armature  724  is now absent, the lock ring  719  is rotated clockwise back to the state shown in FIG. 17A by the lock spring  728 . The lock ring  719  touches and is restrained by the rubber lock  726 , and the sound generated by the lock ring  719  is thus controlled at a low level. 
     A few moments later (20 ms later, for example), control of the correction driving means shown in the timing diagram in FIG. 18 ends. 
     FIG. 19 is a block diagram showing a circuit related to the image-blur correction or image stabilization function only of the camera equipped with the image stabilizing system. 
     The output of shake sensor means  2  is amplified by amplifier means  3 , and then input to an A/D converting terminal of a microcomputer  1 . The output of position sensor means  4  for sensing the position of the correction lens is amplified by amplifier means  5 , and input to an A/D converting terminal of the microcomputer  1 . The microcomputer  1  processes these input data and, outputs correction lens drive data to correction data driving means  6  to drive the correction lens for image stabilization. Lock/unlock driving means  7  drives an unlock coil and maintains an unlock state. 
     Generally speaking, the longer the focal length, the quantity of image blurring on the film plane arising from camera shake gets larger. 
     Suppose that an optional lens is available in a single-lens-reflex camera having a built-in image stabilizing system and that the optional lens allows an extender as a converter for lengthening the focal length. A more accurate image stabilization is required if a higher magnification extender is used. Image stabilization along with a high-magnification extender makes a “sea-sickness” effect more pronounced, and image stabilization conditions are accordingly adjusted. 
     Since the full-aperture F-number gets larger with a higher magnification extender, the shutter time gets slow. A satisfactory image stabilization effect may not be achieved. 
     When a high-magnification extender is mounted, a tripod is frequently used. In such a case, the switching off of image stabilization makes image blurring on the film plane less. If the image stabilization is switched off, however, the image stabilization function cannot be used at all even if the mounted extender is the one having a moderate magnification at which the image stabilization still sufficiently works. 
     SUMMARY OF THE INVENTION 
     According to one aspect of the present invention, a device for use in a camera system which comprises a camera, an optical characteristics modifying converter, and an optical unit having an image stabilizing unit for stabilizing an image in response to the output of a vibration sensor for detecting a shake in an apparatus, includes an activating means for activating the stabilization operation by the image stabilizing unit in response to a predetermined operation in a predetermined operation portion section on the camera, a determining means for determining whether an optical characteristics modifying converter without image stabilization function is incorporated in the camera system, and a decision means for deciding whether to perform the activating operation by said activating means based on the determination by said determining means, wherein the operation of the image stabilizing unit is determined by the incorporation of the converter. 
     According to another aspect of the present invention, a device for use in a camera system which comprises a camera, an optical characteristic modifying converter, and an optical unit having an image stabilizing unit for stabilizing an image in response to the output of a vibration sensor for detecting a shake in an apparatus, includes a determining means for determining whether the optical characteristics modifying converter is incorporated in the camera system, and a variable means for modifying frequency characteristics of the image stabilization operation in response to the determination by the determining means, wherein the operation of the image stabilizing unit is determined by the incorporation of the converter. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a block diagram showing a single-lens-reflex camera and its optional lens assembly according to a first embodiment of the present invention; 
     FIG. 2 is a flow diagram of the main operation of a microcomputer for lens driving of FIG. 1; 
     FIG. 3 is a flow diagram showing a lock/unlock operation executed by the lens-driving microcomputer shown in FIG. 1; 
     FIG. 4 is a flow diagram showing an image stabilization interrupt executed by the lens-driving microcomputer shown in FIG. 1; 
     FIG. 5 is a flow diagram showing a lock/unlock operation executed by a microcomputer in an optional lens assembly according to a second embodiment of the present invention; 
     FIG. 6 is a flow diagram showing an image stabilization operation executed by the microcomputer in the optional lens assembly according to the second embodiment of the present invention; 
     FIG. 7 is a flow diagram showing a lock/unlock operation executed by a microcomputer in an optional lens assembly according to a third embodiment of the present invention; 
     FIG. 8 is a perspective view diagrammatically showing a conventional image stabilization system; 
     FIG. 9 is an exploded perspective view showing the construction of an image stabilizing unit of FIG. 8; 
     FIG. 10 shows the shape of a hole of a support frame of FIG.  8  through which clamp means is inserted; 
     FIGS. 11A and 11B are cross-sectional views partly showing the support frame that is attached to a base plate of FIG. 8; 
     FIG. 12 is a perspective view showing the base plate of FIG. 8; 
     FIG. 13 is a perspective view showing the support frame of FIG. 8; 
     FIG. 14 is a perspective view showing a lock ring of FIG. 8; 
     FIG. 15 is a front view showing the support frame and other associated components shown in FIG. 8; 
     FIG. 16 is a schematic diagram of ICs for amplifying the output of the position sensor devices of FIG. 8; 
     FIGS. 17A and 17B show the lock ring, in operation, of FIG. 8; 
     FIG. 18 shows waveform diagrams of signals during the operation of the lock ring of FIG. 16; and 
     FIG. 19 is a block diagram of a typical camera image stabilization system having an image stabilizing unit. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the drawings, the preferred embodiments of the present invention are discussed. 
     First Embodiment 
     FIG. 1 is a block diagram showing one embodiment of the present invention. Now in the context of the embodiments, an optional lens assembly in a single-lens-reflex camera is assumed as an optical apparatus with an image stabilization function. 
     Referring to FIG. 1, a lens driving microcomputer  101  receives instructions from a camera main unit through a line  109   c  (for a clock signal) and line  109   d  (for lens signal transmission from the camera main unit), and in response to the values of the instructions, operates a stabilization system  102 , a focus driving system  104 , a diaphragm driving system  105 , and controls the stabilization system  102 . 
     The stabilization system  102  comprises a shake sensor  106  such as an angular displacement sensor for sensing a shake, a position sensor  107  for sensing the position of a correction lens, and a stabilization driving system  108  which drives the correction lens for image stabilization or image-blur correction based on a drive signal the lens driving microcomputer  101  computes from the outputs of the shake sensor  106  and position sensor  107 . 
     An image stabilization start switch  124  (also designated as SWIS) starts an image stabilization operation. To select the image stabilization operation, this switch SWIS is turned on. 
     The focus driving system  104  performs focusing by driving a focusing lens in accordance with an instruction from the lens driving microcomputer  101 . The diaphragm driving system  105  closes the diaphragm to a set position or returns the diaphragm to its open setting in accordance to instructions from the lens driving microcomputer  101 . 
     The lens driving microcomputer  101  transmits, to the camera main unit, lens setting data (zoom position, focus position, diaphragm setting) and data about the lens (full-aperture diaphragm stop, focal length, data for rangefinding) via a communication line  109   e  (for transmission from the lens side to the camera main unit). In case of an extender-based lens, communication lines  109   f ,  109   g  and  109   h  for an extender are employed. The lens driving microcomputer  101  monitors the signals from the lines and determines the type of extender. 
     A lens electronic system  110  is constituted by the lens driving microcomputer  101 , stabilization system  102 , focus driving system  104 , and diaphragm driving system  105 . A built-in camera power supply  118  supplies power to the lens electronic system  110  via a communication line  109   a  and a ground line  109   b.    
     The extender contains an extender microcomputer  125 . Besides the communication lines  109   f ,  109   g  and  109   h  to communicate with the lens side, the extender has also communication lines respectively connected to communication lines  109   c ,  109   d , and  109   e.  The built-in camera power supply  118  supplies power to an extender electronic system  126 . 
     The camera main unit includes, in its electronic system  111 , a rangefinding section  112 , a photometric section  113 , a shutter section  114 , a display section  115 , a controller  116 , and a camera microcomputer  117  for controlling these sections, for example to start and stop the camera, and for performing exposure and rangefinding computation. The built-in power supply  118  also supplies power to the camera main unit electronic system  111 . 
     A switch  121  (also designated SW 1 ) starts a photometric operation and a rangefinding operation. A switch  122  (also designated SW 2 ) is a release switch. These switches are jointly constituted by a two-stroke switch. The switch SW 1  is turned on at a first stroke of the two-stroke switch, and the release switch SW 2  is turned on at a second stroke of the two-stroke switch. 
     A switch  123  (also designated SWM) is an exposure mode selection switch. The exposure mode of the camera is changed by switching on and off the switch  123 . The switch  123  is also used in combination with other operation members. 
     The operation of the optional lens of the camera is now discussed. 
     The lens driving microcomputer  101  follows a flow diagram shown in FIG. 2 to control the lens. The operation is now discussed referring to FIG.  2 . 
     When any operation step is taken by the camera, for example, the switch SW 1  is turned on, a signal is communicated between the camera main unit (hereinafter simply referred to as the camera) and the optional lens (hereinafter simply referred to as the lens). The lens driving microcomputer  101  starts operation with step # 1 . 
     Step # 1  Initial setting is made for lens control and image stabilization control. 
     Step # 2  Focus driving is performed in response to a command from the camera. 
     Step # 3  Zoom and focus positions are detected, and the type of a mounted extender is determined. 
     Step # 4  The lock/unlock control of the support frame (correction lens) already described referring to FIG. 17 is performed according to instructions from the camera or the status of the switch SWIS. 
     Step # 5  A determination is made of whether a HALT command (for stopping entirely driving an actuator in the lens assembly) is received from the camera. When the HALT command is not yet received, the lens driving microcomputer  101  repeats step # 2  and subsequent steps. When the HALT command is already received in step # 5 , the lens driving microcomputer  101  goes to step # 6 . 
     Step # 6  HALT control is performed. All driving is stopped, and the lens driving microcomputer  101  goes to a sleep mode (suspended state). 
     When a serial communication interrupt request or image stabilization interrupt request is received from the camera between these steps, such request is honored. 
     The process of a serial communication interrupt includes the decoding of data communicated and lens driving such as diaphragm driving. By decoding the communicated data, the ON state of the switch SW 1  and the ON state of the switch SW 2 , the shutter speed, and the type of the camera are identified. 
     Referring to a flow diagram shown in FIG. 3, the lock/unlock control operation executed in the above step # 4  is now discussed. The image stabilizing unit in this embodiment is identical in construction to that described with reference to FIG.  9 . In this system, the image stabilization operation starts at the moment the main switch, and switches SW 1  and SWIS on the camera are all turned on. 
     Step # 11  It is determined whether the camera main switch is turned on. When it is turned on, the process goes to step # 12 . 
     Step # 12  It is determined whether the camera switch SW 1  is turned on. When it is turned on, the process goes to step # 13 . 
     Step # 13  It is determined whether the switch SWIS is turned on. When it is turned on, the process goes to step # 14 . 
     When the main switch, and switches SW 1  and SWIS are all turned on, the image stabilization operation starts at step # 14 . When one of them remains off, an image stabilization end process in step # 20  and subsequent steps is performed as will be described later. 
     Step # 14  An image stabilization start flag IS_START is set. 
     Step # 15  The unlock attracting magnet is energized. As already described in FIG. 16, this step is required to retain the lock ring rotated against the urging of the lock spring (unlock state). 
     Step # 16  The stabilization drive coil is energized. 
     Step # 17  The lock ring driving coil is energized to rotate the lock ring. 
     Step # 18  It is determined whether a lock ring drive time has elapsed. The lock ring drive time is preset during which the unlock state is kept by the unlock attracting magnet even if the lock ring stops its rotation in the subsequent step # 19 . When the lock ring drive time has not elapsed yet, this subroutine ends, and the same operation is repeated until the lock ring drive time elapses. When the lock ring drive time elapses, the process goes to step # 19 . 
     Step # 19  Energizing the lock ring driving coil is stopped. Now unlock state is entered. 
     As already described, if any of the main switch, and switches SW 1  and SWIS remains off, the image stabilization end process in step # 20  and subsequent steps is performed. 
     Step # 20  The image stabilization flag IS START is cleared. 
     Step # 21  Energizing of the unlock attracting magnet is stopped. The lock spring rotates the lock ring in a lock direction into a locked state. 
     Step # 22  Since there is a possibility that any of the switches is turned off during the lock ring driving, energizing of the lock ring driving coil is stopped just in case. 
     Step # 23  It is determined whether the centering operation for moving the correction lens to the center position of its movable range is completed. When the centering operation is not yet completed, this subroutine ends, and the same operation is repeated until the centering operation is completed. When the end of the centering operation is determined, the process goes to step # 24 . 
     Step # 24  Since the correction lens is at the center position of the movable range, the energizing of the stabilization driving coil is stopped. 
     The lock/unlock operation is thus performed. 
     The image stabilization interrupt is a timer interrupt that is generated at regular intervals (every 500 ms, for example). Since control operation alternates between a pitch (vertical direction) control and a yaw (horizontal direction) control, a sampling interval in one direction is 1 second. Although the same control method (computation coefficients) applies to both pitch and yaw controls, the pitch and yaw controls result in different data. Base addresses are separately set for the pitch and yaw controls, data such as computation results are designated by indirect addresses in RAM, and the base addressed are switched between the pitch control and the yaw control. 
     When an image stabilization interrupt occurs in the middle of the main operation of the camera, the lens driving microcomputer  101  starts image stabilization control at step # 31  as shown in FIG.  4 . 
     Step # 31  The output of shake sensor means, for example, an angular velocity sensor, is A/D-converted. 
     Step # 32  It is determined whether an image stabilization start command is received. When no image stabilization start command is received, the lens driving microcomputer  101  goes to step # 33 . 
     Step # 33  Since no image stabilization is performed, the lens driving microcomputer  101  initializes high-pass filtering and integration computation, and then goes to step # 40 . 
     When it is determined in step # 32  that an image stabilization start command is received, the lens driving microcomputer  101  goes to step # 34 . 
     Step # 34  A high-pass filtering computation is performed to start image stabilization. Within 2 to 3 seconds from the start of image stabilization, the time constant is changed to alleviate image fluctuation at a startup of operation. 
     Step # 35  It is determined whether an extender is mounted. When no extender is mounted, the lens driving microcomputer  101  goes to step # 36 . 
     Step # 36  Since no extender is mounted, the cutoff frequency of integration is set to 0.2 Hz. The lens driving microcomputer  101  goes to step # 39 . 
     When it is determined in step # 35  that an extender is mounted, the lens driving microcomputer  101  goes to step # 37 . 
     Step # 37  The type of the extender is determined. When a 1.4-time magnification extender is mounted, the lens driving microcomputer  101  goes to step # 36  to set integration characteristics (0.2 Hz of cutoff frequency) equal to integration characteristics without extender, because of its relatively low magnification. When a 2-time magnification extender is mounted, the lens driving microcomputer  101  goes to step # 38 . 
     Step # 38  Since the 2-time magnification extender is mounted, integration characteristics having a higher cutoff frequency (0.4 Hz) are set to restrict the seasickness effect. 
     Step # 39  Integration computation of set characteristics is performed. The results are angular displacement data θ. 
     Step # 40  Since the amount of decentration (sensitivity) of the correction lens to shake angle displacement varies depending on focus position, the amount of decentration is adjusted. 
     More specifically, the range of focus is partitioned into several zones, and the average sensitivity (degree/mm) in each zone is read from tabled data and is converted into correction lens drive data. The computation result is stored in RAM area set in SFTDRV in the microcomputer. 
     Step # 41  The output of the position sensor for detecting the position of the correction lens is A/D-converted, and the resulting digital data is stored in the RAM area in SFTPST in the microcomputer. 
     Step # 42  Feedback computation (SFTDRV-SFTPST) is performed. 
     Step # 43  The result of the feedback computation is multiplied by loop gain. 
     Step # 44  To achieve a stable control system, phase compensation computation is performed. 
     Step # 45  The result from the phase compensation computation in PWM is output to a port of the microcomputer, and this ends the interrupt operation. 
     The output of the lens driving microcomputer  101  is input to the stabilization driving system  108  in the stabilization system  102  to drive the correction lens for image stabilization. 
     As described above, steps # 35 -# 38  modify the integration characteristics depending on the presence or absence of the extender and the type of the extender. Even with a high-magnification extender (a 2-time magnification extender in this embodiment) mounted, the seasickness effect conventionally encountered is alleviated, and an optimum image stabilization control is thus performed. 
     In this embodiment, the integration characteristics are changed depending on the presence or absence of the extender and the type of the extender as described above. This change may be performed in the phase compensation computation executed in step # 44 . 
     Second Embodiment 
     In a second embodiment, the image stabilization is not performed when a 2-time magnification extender is mounted. 
     The circuit arrangement of the second embodiment is identical to that of the first embodiment. 
     Referring to flow diagrams shown in FIGS. 5 and 6, the operation of the second embodiment is now discussed. The following discussion focuses on the operation particular to the second embodiment and part of the operation common to the flow diagrams shown in FIGS. 3 and 4 is not discussed. 
     The flow diagram in FIG. 5 is discussed first. The difference from the diagram in FIG. 3 is that the image stabilization flag IS_START is not set when a 2-time magnification extender is mounted. This operation is carried out in steps # 46 -# 47 . 
     Step # 46  A determination is made of whether an extender is mounted. When it is determined that no extender is mounted, the process goes to step # 14  where the image stabilization start flag IS_START is set in the same way as the first embodiment. When it is determined that an extender is mounted, the process goes to step # 47 . 
     Step # 47  The type of the extender is determined. When it is a 1.4-time magnification extender, the process goes to step # 14 , where the image stabilization start flag IS_START is set and the unlocking is performed. When it is a 2-time magnification extender, the process goes to step # 20 , where the image stabilization start flag is cleared and the unlocking is not performed. 
     The operation of image stabilization control is shown in the flow diagram in FIG. 6, which is identical to FIG. 4 but without steps # 35 -# 38 . The image stabilization control is altered depending on the status of the image stabilization start flag IS_START set in the lock/unlock control shown in FIG.  5 . 
     In the subroutine of the lock/unlock control, as described above, the image stabilization start flag IS_START is cleared not to perform image stabilization when a 2-time magnification extender is mounted. When to 1.4-time magnification is mounted, the image stabilization start flag IS_START is set to perform image stabilization. In this way image stabilization is performed only when its performance is fully exhibited. 
     Third Embodiment 
     In a third embodiment, the image stabilization is performed even with a 2-time magnification extender mounted, depending on the type (model) of the camera to which the optional lens is mounted. 
     The circuit arrangement of the third embodiment remains identical to that of the first embodiment. 
     Referring now to a flow diagram shown in FIG. 7, the operation of the third embodiment is discussed. The following discussion focuses on the operation particular to the third embodiment and part of the operation common to the flow diagram shown in FIG. 5 is not discussed. 
     Step # 48  A determination is made of whether a 2-time magnification extender is mounted. When it is determined that no 2-time magnification extender is mounted, the process goes to step # 14 . When it is determined that a 2-time magnification extender is mounted, the process goes to step # 49 . 
     Step # 49  Through communication with the camera, the type of the camera connected to the optical lens is determined. In this embodiment, the communication with the camera about camera status discriminates between camera type A and camera type B. 
     Step # 50  It is determined whether the camera is a type A camera or a type B camera. When it is determined that the camera is a type A camera, the process goes to step # 14 , where image stabilization is performed. When it is determined that the camera is the type B camera, the process goes to step # 20 , where image stabilization is not performed. 
     For example, the type A camera may be the one intended for an experienced photographer and the type B camera may be the one intended for a novice photographer. The experienced photographer may identify the seasickness effect and may judge whether the image stabilization function is fully enjoyed. When the seasickness effect takes place, the switch SWIS is turned off, rendering the image stabilization inoperative and setting the camera operation free from the above problem. The experienced photographer who may be used to seeing stabilized images suffers a relatively milder seasickness effect, and photographs with the image stabilization function switched on by turning the switch SWIS on. 
     The novice photographers may not make the above judgements on their own, and there is a high possibility that they suffer the seasickness effect since they are not used to seeing stabilized images, and it is advisable to disable the image stabilization function. 
     As described above, when a high-magnification extender is mounted, a decision is made not to perform image stabilization depending on the type of the camera. The image stabilization is performed reflecting the skill level of photographers. 
     In the third embodiment, the image stabilization function is enabled or disabled depending on the camera. Alternatively, the integration characteristics may be changed depending on the type of the camera in the same way as the first embodiment. 
     Furthermore, considering the type of the extender mounted on the camera, the integration characteristics may be changed or the image stabilization may be enabled or disabled. 
     Alternate Embodiments 
     In each of the above embodiments, the pitch and yaw controls share the same program. Alternatively, both controls may use different programs. The controls are digital controls in the above embodiments. Alternatively, an analogue control may be used. 
     The image stabilizing unit is installed in the optional lens assembly in the above embodiments. Alternatively, the image stabilizing unit may take the form of an adapter which is inserted between the camera and lens, or which is arranged in a conversion lens attached in front of the optional lens. 
     The present invention may be incorporated in a camera such as a lens-shutter camera or video camera, and further in optical apparatuses such as binoculars and a unit constituting an optical apparatus. 
     In the above embodiments, an angular velocity sensor is used as a shake sensor. Alternatively, any other sensor such as an angular acceleration sensor, an acceleration sensor, a velocity sensor, an angular displacement sensor, a displacement sensor, and means for detecting directly image blurring, may be used as long as it detects shake. 
     The shake sensor means is assembled into the optional lens in the above embodiments. Alternatively, the shake sensor means may be assembled into the camera main unit, and based on a signal from it, a correction lens on the optional lens side may be controlled in position. 
     According to the above embodiments of the present invention, the optical apparatus with the image stabilization function performs optimum image stabilization control according to the optical characteristics modifying converter mounted thereto. 
     According to the above embodiments of the present invention, the optional lens performs optimum image stabilization control according to the camera to which the optional lens is attached to and to the optical characteristics modifying converter attached to the optional lens. 
     The individual components shown in schematic or block form in the drawings are all well-known in the camera arts and their specific construction and operation are not critical to the operation or best mode for carrying out the invention. 
     While the present invention has been described with respect to what is presently considered to be the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, the invention is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.