Abstract:
The invention provides an electronic camera system which operates an electronic camera in a minimum power mode when a not-genuine secondary battery is attached to the electronic camera. Namely, for the electronic camera which uses a detachable secondary battery as a power source, it determines from identification information whether the secondary battery is a genuine battery of the electronic camera. When determining that the secondary battery is a genuine battery, the electronic camera system allows the electronic camera to normally operate. When determining that the secondary battery is not a genuine battery, it places the electronic camera into the minimum power mode.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2004-236012, filed on Aug. 13, 2004, the entire contents of which are incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an electronic device system and an electronic camera system to/from which a secondary battery is attached/detached. It particularly relates to an electronic device system and an electronic camera system suitable for preventing occurrence of accidents such as an explosion of a secondary battery and thereby preventing destruction of an electronic device and an electronic camera to which the secondary battery is attached, to ensure their users&#39; safety. 
     2. Description of the Related Art 
     In recent years, a secondary battery such as a nickel-hydrogen battery, lithium-ion battery, or the like has been widely used as a battery to drive an electronic device such as an electronic camera because of its excellent economic efficiency. 
     Moreover, in order to extend the discharge time of the secondary battery, the realization of the higher-capacity secondary battery has been planned. Therefore, the energy storage amount per unit volume of the secondary battery has been increasing. Due to an increase in the internal temperature of the secondary battery along with overcharge, overdischarge, and so on, and an increase in the internal pressure of the secondary battery, the secondary battery may explode (See Japanese Unexamined Patent Application Publication No. 2004-96919). 
     To prevent such accidents as the explosion of the secondary battery, it is proposed to provide a protection circuit in the secondary battery (See Japanese Unexamined Patent Application Publication No. 2004-6524). 
     An example of the protection circuit of the secondary battery adopts a PTC (Positive Temperature Coefficient) thermistor in the protective circuit. For example, if an excessive current flows into the secondary battery and into the PTC thermistor, the resistance value of the PTC thermistor increases. Consequently, the current which flows into the PTC thermistor is restricted. This can inhibit overcharge and the like to the secondary battery, and accordingly prevent the explosion of the secondary battery due to an increase in the internal temperature of the secondary battery with the overcharge and an increase in the internal pressure thereof. Note that the PTC thermistor has a property that its resistance value decreases as the temperature decreases. Hence, the PTC thermistor is useful as a reusable nondestructive protective component. 
     Further, the internal temperature of the secondary battery is detected as a value of a current, and the detected current is allowed to flow into the PTC thermistor. As a result, when the internal temperature of the secondary battery increases and a large current flows, the resistance value of the PTC thermistor increases, thereby limiting the current flowing into the PTC thermistor. There has been proposed another technique of using this current restriction as a trigger to open an explosion preventing valve provided in the secondary battery and decrease the internal pressure thereof for the explosion prevention. 
     Furthermore, there has been proposed a technique of using a detachable fuel cell from a power source of the electronic device. In this case, it is important to ensure the safety of the electronic device and the fuel cell. In order to achieve this, there has been another technique of allowing the attachment of the fuel cell to the electronic device after confirming that the fuel cell attached to the power source section is a genuine part of the electronic device (See Japanese Unexamined Patent Application Publication No. 2002-280044). 
     In the prior arts, the protection circuit is provided in the secondary battery for prevention of the explosion of the electronic device with the secondary battery attached, so as to ensure their users&#39; safety the explosion of the secondary battery. 
     However, in the world today, there are many so-called imitative batteries with no protection circuit provided. 
     Also, there are secondary batteries provided with the protection circuit which are not ones designed exclusively for the electronic device (hereinafter called a genuine battery) but non-genuine batteries. 
     If the above-described imitative batteries or non-genuine secondary batteries are attached to the electronic device such as a camera, there may cause not only the explosion of the secondary battery but also harm to a body of the electronic device and its user because it is not preventable of the increase in the internal temperature, the internal pressure and the like of the secondary battery. Accordingly, in the electronic device such as the electronic camera, it is necessary to exclude these imitative batteries and non-genuine secondary batteries with an unqualified protection circuit. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide an electronic device system and an electronic camera system which allows an electronic device such as an electronic camera to perform a normal operation when a genuine secondary battery is attached thereto and make it possible to limit the operation of the electronic device such as the electronic camera to a minimum when a not-genuine secondary battery is attached thereto. 
     It is another object of the present invention to provide an electronic camera system which makes it possible to display a state of a secondary battery when an electric camera equipped with the secondary battery is connected to a personal computer. 
     An electronic device system of the present invention has a detachable and chargeable secondary battery, and it includes: a secondary battery determination part which determines whether the secondary battery is a genuine battery which is designed appropriate for an electronic device from identification information; a normal control part which allows the electronic device to operate normally when the secondary battery determination part determines that the second battery is genuine battery; and a minimum power mode shifting part which shifts the operation of the electronic device to a minimum power mode when the secondary battery determination part determines that the secondary battery is not a genuine battery. 
     Further, in the electronic device system of the present invention, the secondary battery determination part detects a state of the secondary battery at regular periods. 
     An electronic camera system of the present invention includes: a secondary battery determination part which determines whether a secondary battery is a genuine battery which is designed appropriate for an electronic camera from identification information; a normal control part which allows the electronic camera to operate normally when the secondary battery determination part determines that the second battery is a genuine battery; and a minimum power mode shifting part which shifts the operation of the electronic camera to a minimum power mode when the secondary battery determination part determined that the secondary battery is not a genuine battery. 
     Further, in the electronic camera system of the present invention, the secondary battery determination part detects a state of the secondary battery at regular periods. Furthermore, the secondary battery determination part transmits the detected state of the secondary battery to a personal computer, and the personal computer displays the detected state of the secondary battery upon receiving. 
     According to the present invention, it is possible for the electronic device such as the electronic camera to perform normal operation when the secondary battery as the genuine battery is attached thereto, and it is possible to limit the operation of the electronic device such as the electronic camera to a minimum when a not-genuine secondary battery is attached. As a result, it is preventable of an explosion of the secondary battery, a breakage of a body of the electronic camera or the electronic device, and any harm to its user. 
     Moreover, according to the present invention, it is possible to display the state of the secondary battery on the personal computer. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The nature, principle, and utility of the invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings in which like parts are designated by identical reference numbers, in which; 
         FIG. 1  is a block diagram showing an embodiment of the present invention; 
         FIG. 2  is a flowchart showing a first operational example of the embodiment shown in  FIG. 1 ; 
         FIG. 3  is a flowchart showing a second operational example of the embodiment shown in  FIG. 1 ; 
         FIG. 4  is a flowchart showing a third operational example of the embodiment shown in  FIG. 1 ; and 
         FIG. 5  is a flowchart showing a fourth operational example of the embodiment shown in  FIG. 1 . 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     An embodiment of the present invention will be described below. 
       FIG. 1  is a block diagram showing the embodiment of the present invention. This embodiment applies the present invention to an electronic camera and corresponds to all claims described in CLAIMS. 
     In  FIG. 1 , numeral  100  denotes an electronic camera, numeral  200  denotes a secondary battery, and numeral  300  denotes a personal computer. 
     A photographing system of the electronic camera  100  is well known, so that portions related to this embodiment will be briefly explained. 
     The electronic camera  100  performs various controls, including a preliminary control before photographing, and executes photographing based on these controls. 
     Namely, as shown, a photographing lens  101  is placed inside the electronic camera  100 , and an image sensor  102  such as a CCD is placed at a position where an optical image obtained via the photographing lens  101  is received. 
     An output of the image sensor  102  is converted into a digital signal via an A/D converter  103  and inputted to a bus  108 . 
     Connected to the bus  108  are a buffer memory  104 , a compression/expansion circuit  105 , an image processing circuit  106 , a liquid crystal monitor  107 , a recording medium  110 , and an interface (denoted as I/F in  FIG. 1 )  111 , respectively. Among them, the image processing circuit  106  is a well-known circuit to perform signal processings such as gamma processing, gray level correction, and the like in sequence. 
     A main CPU  109  controls the buffer memory  104 , the compression/expansion circuit  105 , the image processing circuit  106 , and so on and stores images captured by the image sensor  102  as image data in the recording medium  110 . 
     As shown in  FIG. 1 , a secondary battery  200  is attached to the electronic camera  100  via terminals T 1  to T 6 . 
     The secondary battery  200  includes a secondary battery cell  201 , a CPU  202 , a battery control circuit  203 , and a communication control circuit  204 . 
     A nickel-hydrogen battery, a lithium-ion battery, or the like is commonly used as the second battery cell  201 . 
     The CPU  202  transmits an identification code, battery information, and the like of the secondary battery to the electronic camera  100  through the communication control circuit  204 . Here, the identification code corresponds to identification information set forth in a claim. The battery information signifies the nominal capacity, maximum charging voltage, maximum discharging current, maximum temperature during discharge, date of manufacture, cycle count (the number of charges made until a full charge), number of charges (the number of charges made before a full charge), and so on. 
     The battery control circuit  203  monitors and controls an output voltage and an output current of the secondary battery cell  201  based on a command of the CPU  202 . 
     The CPU  202  checks a secondary battery remaining capacity through the battery control circuit  203  and transmits it to the electronic camera  100  through the communication control circuit  204 . Further, the CPU  202  has a function of, when the secondary battery cell  201  is brought into an overcurrent output state, an overvoltage output state, or a low voltage output state, transmitting the state to the electronic camera  100  through the communication control circuit  204 . Here, the secondary battery remaining capacity, the overcurrent output state, the overvoltage output state, and so on are also included in the above-described battery information. 
     A sub CPU  112  of the electronic camera  100  receives communication from the secondary battery  200  through a communication control circuit  113 . 
     The electronic camera  100  receives electric power supplied from the battery control circuit  203  in the secondary battery  200  through a power control circuit  114 . Incidentally, a line which is directly inputted from the secondary battery cell  201  to the electronic camera  100  is aground-level (GND) line. 
     The power control circuit  114  of the electronic camera  100  receives the supplied power and outputs plural voltages needed in respective sections of the electronic camera. It outputs, for example, plural voltages between 6 V to 8.4 V, a negative voltage, and so on. By these voltages, the electronic camera performs photographing processing, reproducing processing, and so on. 
     Moreover, as shown in  FIG. 1 , the personal computer  300  is connected to the electronic camera  100  via the interface (I/F)  111 . A USB or the like is commonly used as the interface  111 . 
       FIG. 2  is a flowchart showing a first operational example of the embodiment shown in  FIG. 1 . 
     In step S 1 , the main CPU  109  determines whether a power switch of the electronic camera  100  has been operated. If it is determined that the power switch has been operated, operation proceeds to step S 2 . 
     In step S 2 , the main CPU  109  acquires an identification code from the secondary battery  200 . 
     In step S 3 , the main CPU  109  determines whether the secondary battery  200  is a genuine battery based on the identification code. If it is determined that the secondary battery  200  is the genuine battery, the operation proceeds to step S 4 , and if it is determined that it is a non-genuine battery, the operation proceeds to step S 7 . Here, assuming that it is determined that the secondary battery  200  is the genuine battery, the operation proceeds to step S 4 . 
     In step S 4 , the electronic camera  100  performs a normal operation, including the photographing processing and the reproducing processing, and thereafter the operation proceeds to step S 5 . 
     In step S 5 , the main CPU  109  of the electronic camera  100  acquires battery information through the sub CPU  112 . Note that in the operation of this embodiment, a description is made on step S 5  performed after step S 4  for simplicity. However, the present invention is not limited thereto, and the battery information is normally acquired every fixed time. 
     In step S 6 , the main CPU  109  determines whether the power switch has been turned off. If it is determined that the power switch has been turned off, the process ends. If it is determined that the power switch has not been turned off, the process in steps S 4  to S 6  is repeated. 
     Next, a case where in step S 3 , it is determined that the secondary battery  200  is the non-genuine battery will be explained. In this case, the operation proceeds to step S 7 . 
     In step S 7 , the main CPU  109  displays an error message on the liquid crystal monitor  107  of the electronic camera  100 . As the error message, for example, “the battery cannot be authenticated”, “this battery cannot be used” or the like is possible. 
     Then, in step S 8 , the main CPU  109  shifts to a minimum power (sleep) mode. Thereby, all other processings, except switch operation processing, cannot be executed. Consequently, the liquid crystal monitor  107  blacks out. 
     In step S 9 , the main CPU  109  determines whether a switch operation has been performed. If it is determined that the switch operation has been performed, the process in steps S 7  to S 9  is repeated again. 
     According to the embodiment shown in  FIG. 1  and  FIG. 2 , when the non-genuine secondary battery is attached, the electronic camera  100  shifts to the minimum power (sleep) mode. Accordingly, it is possible to exclude the non-genuine secondary battery and thereby ensure the safety of the electronic camera and its user. 
       FIG. 3  is a flowchart showing a second operational example of the embodiment shown in  FIG. 1 . In the second operational example, the battery information on the secondary battery attached to the electronic camera  100  is displayed on the personal computer  300 . 
     The operational example shown in  FIG. 3  is different from the operational example shown in  FIG. 2  in portions in steps S 4  to S 6  in  FIG. 2  and steps S 14  to S 16  in  FIG. 3 . Since the other portions are the same, the description thereof is omitted. 
     In step S 3  shown in  FIG. 3 , if it is determined that the secondary battery  200  is the genuine battery, the operation proceeds to step S 14 . 
     In step S 14 , the main CPU  109  transmits the identification code to the personal computer  300 . Incidentally, the personal computer is denoted as PC in  FIG. 3 . 
     In step S 15 , the main CPU  109  transmits the battery information which is acquired regularly to the personal computer  300  (See step S 5  in  FIG. 2 ). 
     In step S 16 , the personal computer  300  receives the battery information and displays a state of the secondary battery  200  based on the received battery information. 
     According to the embodiment shown in  FIG. 1  and  FIG. 3 , when the secondary battery being the genuine battery is attached, it becomes possible to display the state of the secondary battery  200  on the personal computer  300 . 
       FIG. 4  is a flowchart showing a third operational example of the embodiment shown in  FIG. 1 . The third operational example shown in  FIG. 4  is different from the first operational example shown in  FIG. 2  in that the main CPU  109  acquires the identification code and determines whether the secondary battery  200  is the genuine battery or the non-genuine battery when the secondary battery  200  is attached to the electronic camera  100 . 
     Namely, in step S 21  in  FIG. 4 , the main CPU  109  determines whether the secondary battery  200  has been attached to the electronic camera  100 . It is possible to determine whether the secondary battery  200  has been attached, for example, by the CPU  109  checking a voltage of the terminal T 1  of the electronic camera  100 . More specifically, if the secondary battery  200  is not attached, the voltage of the terminal T 1  of the electronic camera  100  is, for example, 0 V, and if the secondary battery  200  has been attached, the voltage of the terminal T 1  of the electronic camera  100  becomes, for example, 8 V by connection to the terminal T 4 . When detecting the above voltage change, the main CPU  109  determines that the secondary battery  200  has been attached, and the operation proceeds to step S 22 . Incidentally, it is possible to determine whether the secondary battery  200  has been attached to the electronic camera  100  also by determining whether the communication control circuit  113  can communicate with the secondary battery  200  via the terminals T 2  and T 5 . When determining that the secondary battery  200  is not attached, the main CPU  109  repeats the determination in step S 21 . 
     In step S 22 , the main CPU  109  acquires the identification code from the secondary battery  200 . 
     In step S 23 , the main CPU  109  determines whether the secondary battery  200  is the genuine battery based on the identification code. If it is determined that the secondary battery  200  is the genuine battery, the operation proceeds to step S 24 , and if it is determined that the secondary battery  200  is the non-genuine battery, the operation proceeds to step S 25 . 
     In step S 24 , a system internal flag provided on the electronic camera  100  side is set to flag “ 1 ” which indicates that the secondary battery  200  is the genuine battery. 
     In step S 25 , the system internal flag provided on the electronic camera  100  side is set to flag “ 0 ” which indicates that the secondary battery  200  is the non-genuine battery. 
     In step S 26 , the main CPU  109  determines whether the power switch of the electronic camera  100  has been operated. If it is determined that the power switch has been operated and brought into an on-state, the operation proceeds to step S 27 . If it is determined that the power switch has not been operated, the determination in step S 26  is repeated. 
     In step S 27 , the contents of the system internal flag provided on the electronic camera  100  side (already set in step S 24  and S 25 ) are checked. If the system internal flag is “ 1 ” which indicates the genuine battery, the operation proceeds to step S 4 . If the system internal flag is “ 0 ” which indicates the non-genuine battery, the operation proceeds to step S 7 . 
     Since the following process (steps S 4  to S 9 ) is the same as the process in steps S 4  to S 9  shown in  FIG. 2 , the description thereof is omitted. 
       FIG. 5  is a flowchart showing a fourth operational example of the embodiment shown in  FIG. 1 . The fourth operational example shown in  FIG. 5  is different from the second operational example shown in  FIG. 3  in that the main CPU  109  acquires the identification code and determines whether the secondary battery  200  is the genuine battery when the secondary battery  200  is attached to the electronic camera  100 . 
     Namely, steps S 21  to S 27  shown in  FIG. 5  are the same as steps S 21  to S 27  shown in  FIG. 4 , and steps S 7  to S 9  and steps S 14  to S 16  shown in  FIG. 5  are the same as steps S 7  to S 9  and steps S 14  to S 16  shown in  FIG. 3 . Accordingly, the process in the flowchart shown in  FIG. 5  is clear from the description about  FIG. 3  and  FIG. 4 , so that the description thereof is omitted. 
     According to the respective operational examples shown in  FIG. 4  and  FIG. 5 , the process of acquiring the identification code from the secondary battery  200  is limited to when the secondary battery  200  is attached to the electronic camera  100 , so that the risk of leakage of the identification code to the outside can be reduced. 
     Further, according to the respective operational examples shown in  FIG. 4  and  FIG. 5 , the need for identifying the genuine battery or the non-genuine battery every time the power switch is turned on is eliminated, which can contribute to reduced load at the time of starting and reduced starting time when the electronic camera  100  is started. 
     In the above, the description is given on the electronic camera as an example, but the present invention is not limited thereto, and can be applied to any device as long as the device is an electronic device to which the secondary battery is attached. 
     The invention is not limited to the above embodiments and various modifications may be made without departing from the spirit and scope of the invention. Any improvement may be made in part or all of the components.