Abstract:
An electric circuit board system for a camera includes at least one main electric circuit board having a central processing unit for performing a control of a camera, and at least one connection section for having an electric connection with other electric circuit boards. A plurality of unit circuit boards can be connected with the above-described at least one connection section, with mutually different specifications. Any one optional unit circuit board is selected from the plurality of unit circuit boards and is connected to at least one of the main electric circuit boards, for structuring a camera.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates to an electric circuit board system for a camera.  
           [0002]    Jpn. UM. Appln KOKAI Publication No. 63-113135 discloses a structure of a system disposed inside a camera, which system consists of one main circuit board into which there are loaded, in high density, electric devices including a photometric sensor, a dimming sensor, a control circuit device for carrying out an exposure control and a stroboscopic photographing control based on output signals from these sensors, and the like.  
           [0003]    However, according to a conventional electric circuit board system for a camera including the above-described Jpn. UM. Appln KOKAI Publication No. 63-113135, it is necessary to exchange a main circuit board itself when the version of the system is changed to an upgraded version or when it is desired to structure a camera of a different type. Further, as the main circuit board itself has many functions, there is a problem that the size of the main circuit board becomes larger in this case.  
         BRIEF SUMMARY OF THE INVENTION  
         [0004]    The present invention has been made in the light of the above-described problems, and it is an object of the invention to provide an electric circuit board system for a camera capable of obtaining a target camera structure by merely exchanging a relevant unit of a camera when there has been a change in the version of the system or when a type of the camera has been changed to a different type.  
           [0005]    In order to achieve the above object of the invention, according to a first aspect of the invention, there is provided an electric circuit board system for a camera, comprising:  
           [0006]    at least one main electric circuit board having a central processing unit for performing a control of a camera, and at least one connection section for having an electric connection with other electric circuit boards; and  
           [0007]    a plurality of unit circuit boards with mutually different specifications, capable of being connected with the above-described at least one connection section,  
           [0008]    with any one optional unit circuit board being selected from the plurality of unit circuit boards, and being connected to at least one of the main electric circuit boards, for structuring a camera.  
           [0009]    According to a second aspect of the invention, there is provided an electric circuit board structure for a camera structured by combining a plurality of units, the electric circuit board structure comprising:  
           [0010]    a main circuit board provided with a CPU for controlling the whole operation of a camera; and  
           [0011]    an auxiliary circuit board provided on each of the plurality of units, structured to be electrically connectable with the main circuit board, and provided with an electric part relating to each operation of the plurality of units.  
           [0012]    Further, according to a third aspect of the invention, there is provided an electric circuit board system for a camera, comprising:  
           [0013]    at least one main circuit board; and  
           [0014]    a plurality of functional-unit circuit boards for achieving individual functions of a camera,  
           [0015]    with any one functional-unit circuit board being selected from the plurality of functional-unit circuit boards according to a specification of a camera, and being connected to the at least one main circuit board, for structuring a camera.  
           [0016]    Further, according to a fourth aspect of the invention, there is provided an electric circuit board system for a camera, comprising:  
           [0017]    a plurality of kinds of functional electric circuit boards mounted with a sensor or an actuator for achieving an individual function of a camera, and provided with a connection terminal of a common specification for connection with other electric circuit board; and  
           [0018]    a master electric circuit board provided with a plurality of connection terminals to connect with the plurality of kinds of functional electric circuit boards, for integrally controlling the functional electric circuit boards.  
           [0019]    Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter. 
       
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING  
       [0020]    The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate presently preferred embodiments of the invention, and together with the general description given above and the detailed description of the preferred embodiments given below, serve to explain the principles of the invention.  
         [0021]    [0021]FIG. 1 is a view for explaining the outline of an electric circuit board system for a camera to which the present invention is applied.  
         [0022]    [0022]FIG. 2 is a view for showing a state that each module for achieving each function of a camera is connected to a main circuit board.  
         [0023]    [0023]FIG. 3 is a view for showing a state that each unit shown in FIG. 2 is connected to the main circuit board.  
         [0024]    [0024]FIG. 4 is a view for showing in further detail a shape of each flexible circuit board provided on each unit of a camera.  
         [0025]    [0025]FIG. 5 is a view for showing a state that each flexible circuit board shown in FIG. 4 is exposed.  
         [0026]    [0026]FIG. 6 is a view for explaining a first embodiment of the present invention, which shows a structure of a passive AF unit disposed on the main circuit board.  
         [0027]    [0027]FIG. 7 is a view for explaining the first embodiment of the present invention, which shows a structure of an active AF unit disposed on the main circuit board.  
         [0028]    [0028]FIG. 8 is a flowchart for explaining a process of a release sequence in the first embodiment of the present invention.  
         [0029]    [0029]FIG. 9 is a flowchart for explaining a process of an active distance measuring in step S 106  of the flowchart shown in FIG. 8.  
         [0030]    [0030]FIG. 10 is a flowchart for explaining a process of a passive distance measuring in step S 107  shown in FIG. 8.  
         [0031]    [0031]FIG. 11 is a view for explaining a second embodiment of the present invention, which shows a structure of a passive AF unit disposed on a main circuit board.  
         [0032]    [0032]FIG. 12 is a view for explaining the second embodiment of the present invention, which shows a structure of an active AF unit disposed on the main circuit board.  
         [0033]    [0033]FIG. 13 is a view for explaining a third embodiment of the present invention, which shows a structure of a passive AF unit disposed on a main circuit board.  
         [0034]    [0034]FIG. 14 is a view for explaining the third embodiment of the present invention, which shows a structure of an active AF unit disposed on the main circuit board.  
         [0035]    [0035]FIG. 15 is a flowchart for explaining a process of a release sequence in the third embodiment of the present invention.  
         [0036]    [0036]FIG. 16 is a view for explaining a fourth embodiment of the present invention, which shows a structure of a passive AF unit disposed on a main circuit board.  
         [0037]    [0037]FIG. 17 is a view for explaining the fourth embodiment of the present invention, which shows a structure of an active AF unit disposed on the main circuit board.  
         [0038]    [0038]FIG. 18 is a flowchart for explaining a process of a release sequence in the fourth embodiment of the present invention.  
         [0039]    [0039]FIG. 19A is a block diagram for showing a main structure for achieving a super combination AF, and  
         [0040]    [0040]FIG. 19B is a view for showing a pattern of a reflection signal beam incident to an area sensor  502 .  
         [0041]    [0041]FIG. 20 is a flowchart for showing a process of a distance measuring according to the super combination AF. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0042]    Embodiments of the present invention will be explained in detail with reference to the drawings. FIG. 1 is a view for explaining an outline of the embodiments.  
         [0043]    In FIG. 1, there are provided a plurality of, that is, a first to a fifth, main circuit board connectors  2   a  to  6   a  on a main flexible printed circuit board (hereinafter to be referred to as a main circuit board)  100  as a main electric circuit board mounted with a CPU  101  provided with a ROM1  102  for storing a predetermined program and for controlling the whole of a camera. There are also prepared modules  110  to  114 , illustrated as blocks in the drawing, as a plurality of unit circuit boards for achieving various functions to perform the operation of a camera. In the modules  110  to  114 , there are provided module-side connectors  2   b  to  6   b  which can be connected respectively to the main circuit board connectors  2   a  to  6   a.    
         [0044]    The module  110  as an AF/AE finder unit  1  provided with a three-point photometric device  7  can be connected to the main circuit board connector  5   a  of the main circuit board  100  by the module-side connector  5   b.  A module  110 ′ as an AF/AE finder unit  2  provided with a one-point photometric device  8  has the same module-side connector  5   b  as that of the module  110 , and can, therefore, be connected to the main circuit board connector  5   a  in place of the module  110 .  
         [0045]    Further, the module  111  as a mirror frame unit  1  provided with a zoom-encoder photo-reflector  9  can be connected to the main circuit board connector  4   a  of the main circuit board  100  by the module-side connector  4   b.  A module  111 ′ as a mirror frame unit  2  not provided with a photo-reflector has the same module-side connector  4   b  as that of the module  111 , and can, therefore, be connected to the main circuit board connector  4   a  in place of the module  111 .  
         [0046]    The module  112  as a stroboscopic unit can be connected to the main circuit board connector  3   a  of the main circuit board  100  by the module-side connector  3   b.  The module  113  as a cartridge chamber unit can be connected to the main circuit board connector  2   a  of the main circuit board  100  by the module-side connector  2   b.  The module  114  as a film-feeding unit can be connected to the main circuit board connector  6   a  of the main circuit board  100  by the module-side connector  6   b.    
         [0047]    In the above-described structure, according to the present embodiment, it is possible to structure several different types of cameras by exchanging each module connected to the main circuit board  100 . For example, when the modules  110  to  114  are connected to the main circuit board  100  respectively through the main circuit board connectors  3   a  to  6   a  and the module-side connectors  3   b  to  6   b,  it is possible to structure a camera having a zoom lens and capable of center-weighted photometry and an average photometry, as the module  110  has the multi-point, in this case, a three-point, photometric device  7  and the module  111  has the zoom-encoder photo-reflector  9 .  
         [0048]    In this embodiment, when, for example, the module  110 ′ having the one-point photometric device is connected to the main circuit board  100  in place of the module  110 , and when the module  111 ′ of a single focal point and having no zoom encoder is connected to the main circuit board  100  in place of the module  111 , it is possible to structure a camera capable of carrying out only an average photometry with a single focal-point lens, at lower cost than the above-described camera.  
         [0049]    In the case of structuring a camera involving a change of version to an improved version or a camera of a different type, it is also necessary to change a program stored in the ROM1 ( 102 ) to other program. However, in this case, as the hardware structure may be exactly the same, it is possible to easily cope with the change in the type of a camera. FIG. 1 shows a main circuit board  100 ′, having a ROM2 ( 102 ′) which stores a program after the program has been changed.  
         [0050]    As described above, according to the present embodiment, in a camera having a plurality of units for achieving respective functions of the units, when the version of the camera has been changed or when the camera has been changed to a camera of other type, it is possible to obtain a target camera by simply exchanging relevant units. Because of this characteristic, it is also possible to provide cameras at low cost through a common use of the cameras. Further, it is also possible to guarantee the performance of a camera at the time of assembling the camera, by simply checking the functions and performance of units for achieving the relevant functions of the camera.  
         [0051]    [0051]FIG. 2 is a view for illustrating a state how the above-described modules (units)  110  to  114  are connected to the main circuit board  100 . The AF/AE finder unit  110  having a finder field of vision frame  110   a  and having accommodated therein AF and AE devices (such as a light-emitting device, a light-receiving device, a photometric device), and a finder optical system, is installed with a flexible circuit board  110   b. The module-side connector  5   b  of the flexible circuit board  110   b  is connected to the main circuit board connector  5   a  of the main circuit board  100 .  
         [0052]    The mirror frame unit  111  for accommodating a photographic lens system and a photo-interruptor for detecting a focal distance, is installed with a flexible circuit board  111   a.  The module-side connector  4   b  of the flexible circuit board  111   a  is connected to the main circuit board connector  4   a  of the main circuit board  100 . Through the module-side connector  4   b,  there are input a signal for driving a lens focusing motor and a signal for executing a stopping or a zooming, and there are also output a detection signal from the photo-interruptor.  
         [0053]    The film feeding unit  114  as a driving system unit is installed with a spool  114   b  incorporating a motor  114   c,  and the flexible circuit board  114   a  having the module-side connector  6   b.  A spool chamber  114   d  is installed so as to surround the spool  114   b.  Inside the film feeding unit  114 , there are accommodated gears and various kinds of switches for transmitting a driving force from the motor  114   c,  and a photo-interruptor for detecting a movement of a film. The module-side connector  6   b  of the flexible circuit board  114   a  fitted to the film feeding unit  114 , is connected to the main circuit board connector  6   a  of the main circuit board  100 .  
         [0054]    The cartridge chamber unit  113  is installed with a screw hole as the module-side connector  2   b,  and a flexible circuit board  113   a  provided with positioning boss holes  120 - 2  and  121 - 2 . In the case of a camera for a new film, there are stored inside the cartridge chamber unit  113 , a photo-interruptor and a photo-reflector for reading the ISO sensitivity of a film expressed in an information code on a data disk of a film cartridge, and the number of frames of the film. In the case of a 135-type camera, there is provided inside the cartridge chamber unit  113 , a contact point of a DX code. Around the screw hole  2   b  of the flexible circuit board  113   a  and also at the rear side of this flexible circuit board, a gold-plated pattern  123 - 2  is provided.  
         [0055]    The main circuit board  100  is also provided with a screw hole as the main circuit board connector  2   a  and positioning boss holes  120 - 1  and  21 - 1 . A gold-plated pattern  123 - 1  is provided around them. By superimposing the two screw holes  2   a  and  2   b  and fixing them together with a screw, the flexible circuit board  113   a  is connected to the main circuit board  100 .  
         [0056]    The stroboscopic unit is structured by strobo-scopic unit  112 - 1  and  112 - 2 . Inside the stroboscopic unit  112 - 1 , there are accommodated a light-emitting tube for executing a stroboscopic light emission, and a reflection umbrella. A lead wire  112   d  is extracted from the inside of the unit to the outside and is fixed to a stroboscopic circuit board  112   e  of the stroboscopic unit  112 - 2  to be described later.  
         [0057]    The stroboscopic unit  122 - 2  consists of a main capacitor  112   a,  a transformer  112   c  for increasing a voltage, and a stroboscopic circuit board  112   e  mounted with a light-emitting circuit not shown. A flexible circuit board  112   b  is fitted between the main capacitor  112   a  and the stroboscopic circuit board  112   e.  An extended part of the flexible circuit board  112   b  is provided with a screw hole for stopping a screw as the module-side connector  3   b,  and positioning boss holes  120 - 3  and  121 - 3 . A metal-plated pattern  123 - 3  is provided around the boss hole  3   b.  By superimposing the two screw holes  3   a  and  3   b  and fixing them together with a screw, the flexible circuit board  112   b  is connected to the main circuit board  100 .  
         [0058]    Further, a supporting plate  103  for supporting the main circuit board  100  is provided with a screw hole  103   a.  This screw hole  103   a  and a screw hole  103   a′  of a spool chamber  114   d  are superimposed and are fixed together with a screw. The supporting plate  103  is also provided with a screw hole  103   b,  and this screw hole  103   b  and a screw hole  103   b,  of the cartridge chamber unit  113  are superimposed and are fixed together with a screw. The supporting plate  103  is provided with screw holes  103   c  and a  103   d.  The screw holes  103   c  and  103   d  and screw holes  103   c′  and  103   d′  of the film feeding unit  114  are superimposed and are fixed together with a screw.  
         [0059]    [0059]FIG. 3 is a view for showing a state that the above-described units are connected to the main circuit board  100  by their flexible circuit boards. The main circuit board  100  is a portion illustrated by shaded lines.  
         [0060]    [0060]FIG. 4 is a view for showing in further detail the above-described flexible circuit boards. To the main circuit board connector  5   a  of the main flexible circuit board  100 , there is connected an AF module  110  consisting of a pair of passive devices, and there is also connected a finder flexible circuit board  110   b  having an island-shaped portion  203  for installing a photometric device. To a return section  100   a  of the main flexible circuit board  100 , there is connected by thermocompression-bonding a relay flexible circuit board  180  having a display LCD  208  bonded thereto by thermocompression. To the main circuit board connector  6   a  of the main flexible circuit board  100 , there is connected via the return section  100   a  a film feeding flexible circuit board  114   a  installed with a motor photo-interruptor  200  for detecting a rotation of a film driving motor, a photo-interruptor  201  for changing over a film feeding, and a photo-interruptor  207  for detecting a completion of a change-over of a driving system.  
         [0061]    A mirror frame flexible circuit board  111   a  is connected to the main circuit board connector  4   a  of the main flexible circuit board  100 .  
         [0062]    Further, a screw hole as the main circuit board connector  2   a  of the main flexible circuit board  100  and a screw hole  2   b  as the cartridge flexible circuit board  113   a  are superimposed and are fixed together with a screw, so that the cartridge flexible circuit board  113   a  is connected to the main flexible circuit board  100 . Similarly, a screw hole as the main circuit board connector  3   b  and the screw hole  3   b  of the stroboscopic flexible circuit board  112   b  installed with the main capacitor  112   a,  the stroboscopic circuit board  112   e,  an IGBT  204  for controlling a stroboscopic light emission, and a trigger transformer  205 , are superimposed and are fixed together with a screw, so that the stroboscopic flexible circuit board  112   b  is connected to the main flexible circuit board  100 .  
         [0063]    Further, the main flexible circuit board  100  is provided with a magnetic head  202  and a gold-plated pattern  206  to be used for checking whether a camera is operating normally or not.  
         [0064]    [0064]FIG. 5 is a view for showing a state that each flexible circuit board illustrated in FIG. 4 is exposed. The mirror frame flexible circuit board  111   a  is provided with a photo-interruptor pattern (LDPI)  303  for detecting a lens driving position, a photo-interruptor pattern (AEPI)  304  for detecting a movement of a shutter blade, and a photo-reflector pattern (ZPR)  305  for detecting a focal distance. The mirror frame flexible circuit board  111   a  is installed with a plunger  301  for opening and closing a shutter by a lead wire  300 . At the same time, a motor (LD motor)  302  for driving a focusing lens is soldered in a pierced state in the mirror frame flexible circuit board  111   a.  The module-side connector  4   b  of the mirror frame flexible circuit board  111   a  is connected to the main circuit board connector  4   a  of the main flexible circuit board  100 .  
         [0065]    The finder flexible circuit board  110   b  is installed with a pattern (AE)  310  for a photometric device, a pattern (PARSW)  312  for a screen size change-over switch, a pattern (FLED)  313  for a finder display LED, and a pattern (AF)  314  for an AF module. The module-side connector  5   b  of the finder flexible circuit board  110   b  is connected to the main circuit board connector  5   a  of the main flexible circuit board  100 .  
         [0066]    The film feeding flexible circuit board  114   a  is provided with a pattern (clutch PI)  320  for a clutch photo-interruptor, a pattern (motor PI)  321  for a motor photo-interruptor for detecting a rotation of the film driving motor, a pattern  327  for a photo-interruptor for detecting a completion of a change-over, and a pattern  326  for an eject switch for opening and closing a lid of a cartridge chamber. At the same time, the film feeding flexible circuit board  114   a  is connected with a plunger (WZ plunger)  322  for changing over a driving force through a lead wire  324 , and a remote control light receiving device  323  through a lead wire  325 . The module-side connector  6   b  of the film feeding flexible circuit board  114   a  is connected to the main circuit board connector  6   a  of the main flexible circuit board  100 .  
         [0067]    Further, the main flexible circuit board  100  is connected with a spool motor (WZ motor)  331  through a lead wire  330 , and is also connected with a splash type stroboscopic switch  332  through a lead wire  333 . Further, the main flexible circuit board  100  is provided with a pattern (WPR)  341  for a photo-reflector for detecting a wind-up of a film, a pattern  340  for a magnetic head, a gold-plated pattern  206  for checking the operation of a camera, and a pattern  343  for a zoom switch.  
         [0068]    The relay flexible circuit board  180  is provided with various kinds of switch patterns including a pattern (SET MODE)  360  for a date and time setting button, a pattern (SELF)  361  for a self-photographing button, a pattern  362  for a wind-back switch, and a pattern  363  for a stroboscopic mode change-over switch. A connection section  20   b  of the relay flexible circuit board  180  is bonded by thermocompression to a connection section  20   a  of the main flexible circuit board  100 . The other connection section  20   c  of the relay flexible circuit board  180  is bonded by thermocompression to a connection section  20   d  of a display LCD  208 .  
         [0069]    The stroboscopic circuit board  112   e  is connected with a xenon (Xe) tube  371  through a lead wire  370 . This xenon tube  371  is connected to a trigger transformer  205  through a lead wire  373 . The stroboscopic flexible circuit board  112   b  is connected, through a lead wire  376 , with a barrier switch (BRSW)  375  as a main switch for starting a camera. At the same time, the trigger transformer  205  is soldered to the stroboscopic flexible circuit board  112   b  in a pierced state. This portion is connected to the stroboscopic flexible circuit board  112   e  through a lead wire  374 . Further, a connection section  21   a  of the stroboscopic circuit board  112   e  is soldered to a connection section  21   b  of the stroboscopic flexible circuit board  112   b.  The module-side connector  3   b  of the stroboscopic flexible circuit board  112   b  is connected to the main circuit board connector  3   a  of the main flexible circuit board  100 .  
         [0070]    The cartridge flexible circuit board  113   a  is provided with a pattern  380  for a self-photographing LED, a pattern  381  for a cartridge lid open/close detecting switch (BKSW), a pattern  382  for a release switch, and patterns  383 - 1  and  383 - 2  for a bar-code reading photo-reflector. The module-side connector  2   b  of the cartridge flexible circuit board  113   a  is connected to the main circuit board connector  2   a  of the main flexible circuit board  100 .  
         [0071]    There will be explained in detail below embodiments of the invention by taking an example of selectively connecting to the main circuit board a passive AF unit and an active AF unit as a plurality of unit circuit boards.  
         [0072]    [0072]FIG. 6 and  7  are views for explaining a first embodiment of the present invention. FIG. 6 shows a structure having a passive AF unit disposed on a main circuit board. A CPU  1105  carries out various calculations, an input of AF data output from a passive AF flexible circuit board  1104 , an A/D conversion, and an output of various kinds of control signals. The CPU  1105  is connected with a non-volatile memory  1109  such as an EEPROM for storing values of F_ACTIVE (active flag) to be described later, and various kinds of set values and adjusted values. As values of F_ACTIVE, “1” is written for an active distance measuring, and “0” is written as a passive distance measuring, at the time of assembling a camera.  
         [0073]    A passive AF module  1106  includes light receiving lenses  1101   a  and  1101   b  for forming an image of an object on line sensors to be described later, and line sensors  1102   a  and  1102   b  for photoelectrically converting an image of the object image-formed by the light-receiving lenses  1101   a  and  1101   b,  according to a light intensity, and for integrating the image. At the same time the passive AF module  1106  has such a structure that an AFIC  1103  for controlling the integration operation by the line sensors  1102   a  and  1102   b  and for outputting sensor data and monitor data for integration control is integrated together with a light-shielding case not shown.  
         [0074]    The passive AF flexible circuit board  1104  connects lines between a terminal of the AFIC  1103  and each port, (ten ports in total in the drawing) of the CPU  1105 . A reference numeral  1107  denotes a land for soldering the terminal of the AFIC  1103  to the passive AF flexible circuit board  1104 . A reference numeral  1108  denotes a connector for connecting a main circuit board not shown with the passive AF flexible circuit board  1104  or the active AF flexible circuit board  1205 .  
         [0075]    Further, in FIG. 6, VDD denotes a power source line for the AFIC  1103 , AFCEN denotes a control line for turning on and off the power source of the AFIC  1103 , RESET denotes a reset control line for the AFICI  1103 , CLK denotes a clock line for serial communications between the AFIC  1103  and the CPU  1105  and for reading sensor data, DATA denotes a serial communications data line between the AFIC  1103  and the CPU  1105 , MON denotes a sample hold control line relating to monitor data, END denotes an output line of an integration end signal (output of the AFIC  1103 ), AFDATA denotes an output line of sensor data (output of the AFIC  1103 ), MDATA denotes an output line of monitor data, that is an output of the AFIC  1103 , and GND denotes a ground line.  
         [0076]    [0076]FIG. 7 shows a structure having the active AF unit disposed on the main circuit board. In FIG. 7, elements identical with those in FIG. 6 are attached with the identical reference numerals, and their explanation will be omitted.  
         [0077]    The active AF module  1116  is mounted with an IRED  1112  for generating infrared rays, a projection lens  1110   b  for projecting a light from the IRED  1112  to an object, a light-receiving lens  1110   a  for receiving a diffused reflection beam from the object, and a PSD  1111  for outputting currents IA and IB at a rate according to incident positions of reflection beams from the object.  
         [0078]    The active AF flexible circuit board  1114  is also mounted with an AFIC  1113  for controlling a light emission from the IRED  1112 , calculating a rate of the output currents IA and IB of the PSD  1111  and outputting AF data, an IRED driver  1117  for driving the IRED  1112 , and distance measuring parts not shown of a capacitor and the like.  
         [0079]    A reference numeral  1115  denotes a land for mounting the PSD  1111  and the IRED  1112 . This land becomes a connector for connecting signal lines between the PSD  1111  and the IRED  1112  when they are on different circuit boards.  
         [0080]    In FIG. 7, VDD denotes a power source line for the AFIC  1113 , AFCEN denotes a control line for turning on and off the AFIC  1113 , DO to D 3  denote data lines for controlling the AFIC  1113 , ALATCH denotes an address latch line for inputting address data to the AFIC  1113 , DLATCH denotes a data latch line for inputting data to the AFIC  1113 , CPO denotes an AF data output line (an output of the AFIC  1113 ), and GND denotes a ground line.  
         [0081]    [0081]FIG. 8 is a flowchart for explaining a process of the release sequence. At first, in step S 101 , various kinds of set values and adjusted values including F_ACTIVE (the active flag) are read from the non-volatile memory  1109  such as an EEPROM, and they are expanded on the RAM of the CPU  1105 . In the next step S 102 , a decision is made as to whether the power source of the camera has been turned off or not. When the power source has been turned off, the photographing operation is finished. When the power source of the camera is on, the process proceeds to step S 103 . In step S 103 , a decision is made as to whether the first release (1R) switch is on or not. When the switch is on, the process proceeds to step S 104 . When the switch is off, the process returns to step S 102 .  
         [0082]    In step S 104 , the luminance of an object is measured (photometry), and an exposure volume is calculated based on the measured light value obtained. Next, in step S 105 , a decision is made as to whether F_ACTIVE is 1 or not, based on the contents read from the nonvolatile memory  1109  in step S 101 . When the result is YES, the process proceeds to step S 106 . When F_ACTIVE is 0, the process proceeds to step S 107 .  
         [0083]    In step S 106 , a program for the active AF is started to carry out an active distance measuring. In step S 107 , a program for the passive AF is started to carry out a passive distance measuring. After step S 106  or step S 107 , the process proceeds to step S 108 , and a send-out volume of a focus adjusting lens is calculated based on the result of the distance measuring. In the next step S 109 , a decision is made as to whether the first release (1R) switch is off or not. When the switch is off, the process returns to step S 102 . When the switch is on, the process proceeds to step S 110 . In step S 110 , a decision is made as to whether a second release (2R) switch is on or not. When the switch is on, the process proceeds to step S 111 . When the switch is off, the process returns to step S 109 .  
         [0084]    In step S 111 , the focus-adjusting lens is driven based on the sent-out volume of the lens obtained in step S 108 . In the next step S 112 , a film is exposed with a light based on the exposure volume obtained in step S 104 . In the next step S 113 , one frame of the film is wound up, and the process returns to step S 102 .  
         [0085]    [0085]FIG. 9 is a flowchart for explaining the process of the active distance measuring mentioned in step S 106 . At first, in step S 120 , a capacitor not shown for holding steady beams is charged in order to cut steady beams which are being incident. Next, in step S 121 , a signal beam is projected to an object and the signal beam currents IA and IB based on the reflection beams are taken into the AFIC  1113 , and a rate is calculated to obtain the AF data. In the next step S 122 , the AF data is read from the AFIC  1113 , and this data is taken into the CPU  1105 . In the next step S 123 , the CPU  1105  converts the read AF data into 1/L (1/distance) data.  
         [0086]    [0086]FIG. 10 is a flowchart for explaining the process of the passive distance measuring mentioned in step S 107 . At first, in step S 130 , integration conditions such as a sensor sensitivity and an integration time are set. In the next step S 131 , a sensor integration is carried out, and an image of an object is taken into the AFIC  1103 . In the next step S 132 , the CPU  1105  reads the sensor data from the AFIC  1103 , A/D converts the data, and stores the result in the RAM.  
         [0087]    In step S 133 , a correlation and an interpolation are carried out by using the sensor data read in step S 132 , and AF data is calculated. In the next step S 134 , the AF data is converted into 1/L (1/distance) data.  
         [0088]    [0088]FIGS. 11 and 12 are views for explaining a second embodiment of the present invention. The second embodiment is characterized in that the nonvolatile memories such as the EEPROM disposed on the main circuit board in the first embodiment are disposed on the active and passive AF flexible circuit boards respectively. In this case, the nonvolatile memories such as the EEPROM may be separate parts to be exclusively used for the AF.  
         [0089]    [0089]FIG. 11 shows a structure having the passive AF unit disposed on the main circuit board. A passive AF flexible circuit board  1204  is for connecting lines between each port of the terminal of an AFIC  1203  and a CPU  1205 . The passive AF flexible circuit board  1204  has mounted thereon a nonvolatile memory  1209  such as an EEPROM for storing F_ACTIVE (active flag) and various kinds of set values and adjusted values. In this case, the F_ACTIVE is set equal to 0 for the passive AF.  
         [0090]    In FIG. 11, NC denotes a non-connection. CLK denotes a clock line for serial communications between the AFIC  1203  and the CPU  1205  and for reading sensor data, as well as a clock line for serial communications between the EEPROM  1209  and the CPU  1205 . DATA denotes a data line for serial communications between the AFIC  1203  and the CPU  1205 , as well as a data line for serial communications between the EEPROM  1209  and the CPU  1205 . EPSEN denotes a chip selection control line for the EEPROM  1209 , and PROTECT denotes a write protection control line for the EEPROM  1209 . Other structures are similar to those of the first embodiment, and their explanation will be omitted.  
         [0091]    [0091]FIG. 12 shows a structure having the active AF unit disposed on the main circuit board. In FIG. 12, an active AF flexible circuit board  1214  has mounted thereon a PSD  1211 , an IRED  1212 , an AFIC  1213 , an IRED driver  1216 , distance measuring parts not shown such as a capacitor, and a nonvolatile memory  1217  such as an EEPROM. The nonvolatile memory  1217  stores F_ACTIVE (active flag) and various kinds of set values and adjusted values. In this case, the flag F_ACTIVE is set equal to 1 for the active AF.  
         [0092]    In FIG. 12, CLK denotes a clock line for serial communications between the EEPROM  1209  and the CPU  1205 , DATA denotes a data line for serial communications between the EEPROM  1209  and the CPU  1205 , EPSEN denotes a chip selection control line for the EEPROM  1209 , and PROTECT denotes a write protection control line for the EEPROM  1209 . Other structures are similar to those of the first embodiment, and their explanation will be omitted.  
         [0093]    The process of the release sequence in the second embodiment is basically similar to that of the first embodiment. In this case, when the passive AF unit or the active AF unit has been connected to the main circuit board, the contents of the nonvolatile memory  1209  or  1217  are read by the CPU  1205 , and a distance measuring system is determined based on the value of F_ACTIVE in this case.  
         [0094]    [0094]FIGS. 13 and 14 are views for explaining a third embodiment of the present invention. According to the third embodiment, an active/passive decision port P_AFSEL is provided in the CPU, and a decision is made as to whether an active AF control is carried out or a passive AF control is carried out, based on whether the input level of the port P_AFSEL is a VDD level (H level) or a GND level (L level).  
         [0095]    [0095]FIG. 13 shows a structure having a passive AF unit disposed on the main circuit board. In FIG. 13, AFSEL denotes an active/passive decision line. When a passive AF flexible circuit board  1304  is connected, GND on the passive AF flexible circuit board  1304  and the port P_AFSEL of a CPU  1305  are connected.  
         [0096]    [0096]FIG. 14 shows a structure having the active AF unit disposed on the main circuit board. In FIG. 14, AFSEL denotes an active/passive decision line. When an active AF flexible circuit board  1314  is connected, VDD on the active AF flexible circuit board  1314  and P_AFSEL of a CPU  1305  are connected. Other structures are similar to those of the first embodiment.  
         [0097]    [0097]FIG. 15 is a flowchart for explaining a process of the release sequence in the third embodiment. In this flowchart, in step S 305 , a decision is made as to whether the port P_AFSEL of the CPU  1305  is H (VDD level) or not. When the decision is YES, the process proceeds to step S 306 , and an active distance measuring is carried out. When the decision is NO, the process proceeds to step S 307 , and a passive distance measuring is carried out. In other words, according to the third embodiment, when the passive AF unit or the active AF unit has been connected to the main circuit board, a voltage level of the port P_AFSEL is detected, and a distance measuring system is determined according to the voltage level in this case (VDD or GND). Other steps are similar to those of the first embodiment.  
         [0098]    [0098]FIGS. 16 and 17 are views for explaining a fourth embodiment of the present invention. FIG. 16 shows a structure having the passive AF unit disposed on the main circuit board, and FIG. 17 shows a structure having the active AF unit disposed on the main circuit board.  
         [0099]    The fourth embodiment is characterized in that an active/passive decision line AFSEL is provided on an active AFIC  1413  and a passive AFIC  1403  respectively, and when it has been detected that the control line AFCEN changed from the H level to the L level, the line AFSEL is controlled to the H level or the L level.  
         [0100]    In other words, when a passive AF unit as shown in FIG. 16 has been connected to the main circuit board, a signal of the L level is output from a CPU  1405  to an AFIC  1403  through the control line AFCEN. The AFIC  1403  outputs to the CPU  1405  a signal for making the active/passive decision line AFSEL to the L level when a change of the control line AFCEN from the H level to the L level has been detected. Thus, the CPU  1405  can decide that the passive AF unit has been connected.  
         [0101]    Further, when an active AF unit as shown in FIG. 17 has been connected to the main circuit board, a signal of the L level is output from the CPU  1405  to an AFIC  1413  through the control line AFCEN. The AFIC  1413  outputs to the CPU  1405  a signal for making the active/passive decision line AFSEL to the H level when a change of the control line AFCEN from the H level to the L level has been detected. Thus, the CPU  1405  can decide that the passive AF unit has been connected.  
         [0102]    In this case, the AFSEL output, when the control line AFCEN has been changed from the H level to the L level, may be set such that the active is equal to the H level and the passive is equal to the L level. Conversely, it may also be set such that the active is equal to the L level and the passive is equal to the H level.  
         [0103]    Further, a signal input for the CPU to obtain the AFSEL output may not be the control line AFCEN. For example, when some data has been transmitted to the AFIC by serial communications, the AFIC may make an output of the AFSEL. The rest of the operation is similar to that of the first embodiment.  
         [0104]    [0104]FIG. 18 is a flowchart for explaining a process of the release sequence relating to the fourth embodiment. In this embodiment, in step S 405 , a port P_AFCEN corresponding to the control line AFCEN is set to the L level. In step S 406 , a decision is made as to whether a port P_AFSEL corresponding to the active/passive decision line AFSEL is equal to the H level or not. When the decision is YES, the process proceeds to step S 407  to carry out an active distance measuring. When the decision is NO, the process proceeds to step S 408  to carry out a passive distance measuring. In other words, according to the fourth embodiment, when the passive AF unit or the active AF unit has been connected to the main circuit board, the AFIC  1403  or  1414  detects that the port P_AFCEN has been set to the L level by the CPU  1405 , and transmits to the CPU  1405  a signal for making the port P_AFSEL to the L level or the H level. Thus, the CPU  1405  can know which one of the AF units has been connected. The rest of the operation is similar to that of the first embodiment.  
         [0105]    According to the structures of the third embodiment and the fourth embodiment, the CPU makes a decision as to whether the active AF unit has been connected or the passive AF unit has been connected, based on the signal level of the active/passive decision line AFSEL. However, as the value of F_ACTIVE is stored in both the nonvolatile memories  1309  (in the case of the third embodiment) and  1409  (in the case of the fourth embodiment) connected to the CPU, both data may be compared with each other and a distance measuring is carried out only when both data coincide with each other. By this comparison, it is possible to decide, for example, whether the data within the nonvolatile memory is correct or not.  
         [0106]    Further, in the fourth embodiment, it is possible to arrange such that when the AF unit is connected to the main circuit board, the CPU transmits a specific binary code to the AFIC through the control line AFCEN, and makes a decision as to whether a normal AF unit has been connected or not, based on a binary code transmitted from the AFIC in response to the binary code sent to the AFIC. By this arrangement, it is also possible to decide whether a version of the AF unit is different from that used in the system or not although the type of the AF unit is the same as that used in the system.  
         [0107]    In the above-described embodiments, a description has been made about a structure in which the active AF unit and the passive AF unit can be selectively connected to one main circuit board. However, it is needless to mention that units which can be connected to the main circuit board are not limited to the active AF unit and the passive AF unit, but a super-combination AF unit to be described hereunder can also be connected to the main circuit board.  
         [0108]    A new-type auto-focusing technique called a super-combination AF system will be explained below. This auto-focusing technique is not a simple combination of the conventional active AF system and passive AF system. This system carries out a detection of a main object by a combined use of these two systems.  
         [0109]    [0109]FIG. 19A is a block diagram for showing a main structure for achieving the super-combination AF. Beams from an object  520  are incident to two area sensors  502   a  and  502   b  through two light-receiving lenses respectively. These area sensors  502   a  and  502   b  are for receiving beams of the object  520  and then photoelectrically converting the beams. Outputs from these area sensors are A/D converted by an A/D converter  502   c,  and digital values of pixels are input to a microcomputer (CPU)  501  for controlling a camera.  
         [0110]    The area sensors  502   a  and  502   b  are connected with a steady-beam removing circuit  502   d.  When this steady-beam removing circuit  502   d  is controlled by the CPU  501 , a DC light signal steadily incident from the object  520  is removed, and only a pulse beam from a light source  505   a  is obtained as an output signal.  
         [0111]    Accordingly, when the CPU  501  controls light-emitting means  505  to drive the light source  505   a  and irradiates beams to the object  520  in a state that the steady-beam removing circuit  502   d  is being operated, an image pattern as shown in FIG. 19B is formed on the area sensors  502   a  and  502   b  based on reflection signal beams from the object  520 . FIG. 19B shows a state that beams are incident to a black portion. The CPU  501  is built with a software for analyzing an image pattern formed on the area sensors  502   a  and  502   b.  When a decision is made based on this software that the image pattern is a shape of a man, this image pattern can be regarded as a main object.  
         [0112]    [0112]FIG. 20 is a flowchart for showing a process of a distance measuring based on the above-described super-combination AF. At first, in steps S 501  and S 502 , the light source  505   a  is driven prior to the distance measuring, and only a pattern of a reflection signal beams as shown in FIG. 19B is taken out. In the next step S 503 , a decision is made as to whether this pattern is a main object or not, based on the shape of a man. When the decision is YES, the process proceeds to step S 504 . In step S 504 , a decision is made as to whether the intensity of beams forming the above pattern is strong or not, or whether there is a sufficient contrast or not. Based on this decision, a selection is made as to which one of an active system and a passive system is to be used as a light measuring system; the active system is of a type for measuring a distance from an object based on a signal beam emitted from a camera side to the object and a reflection signal beam received from the object; and the passive system is of a type for measuring the distance based on an image signal of the object.  
         [0113]    In other words, when the contrast of the image signal is weak, the process branches to step S 510 , and the active AF is carried out with an emphasis on the position of the main object obtained earlier, by irradiating a distance-measuring beam again to the object and obtaining reflection signal beams (after removal of steady beams) from the object.  
         [0114]    Further, when a decision has been made that the intensity of the reflection signal beams is low in step S 504 , a decision is made that the passive AF is suitable, and the process branches to step S 505 . In this case, a distance measuring is carried out according to the passive system mainly using the image signal at the position of the main object obtained earlier.  
         [0115]    When a main object has not been able to be detected in step S 503 , a luminance signal or the like is added, and the active system or the passive system is selected. Thereafter, a distance is measured with an emphasis on a screen center portion where there is a high possibility of the existence of the object.  
         [0116]    Further, in steps S 506 , S 512  and S 521 , the CPU  501  carries out a control so that a plurality of voice signals are output, that is, a voice pattern  2 , a voice pattern  3  and a voice pattern  1 , according to a YES or NO decision result of the above-described distance measuring systems or the main object. With this arrangement, a user can carry out a distance measuring easily and with comfort by taking the advantage of the super-combination AF.  
         [0117]    According to the present invention, it is possible to obtain a target camera structure by merely exchanging a relevant unit of a camera when there has been a change in the version of the system or when a type of the camera has been changed to a different type. Because of this advantage of camera structure, cameras can be used commonly in manufacturing stages, so that cameras can be provided at low cost.  
         [0118]    Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.