Abstract:
A body-insertable apparatus includes a function execution unit which executes a predetermined function in a subject into which the body-insertable apparatus is introduced; an electric power storage unit which stores driving electric power for driving the function execution unit; a detection unit which detects electric power supplied from the electric power storage unit; and an exhaustion unit which is provided to be separated from the function execution unit and exhausts the electric power of the electric power storage unit based on a detection result of the detection unit.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is a continuation of PCT international application Ser. No. PCT/JP2004/015375 filed Oct. 18, 2004 which designates the United States, incorporated herein by reference, and which claims the benefit of priority from Japanese Patent Application No. 2003-364607 filed Oct. 24, 2003, incorporated herein,by reference.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to a body-insertable apparatus which supplies electric power to each electric portion of, for example, a capsule endoscope of a swallow type. More specifically, the present invention relates to a body-insertable apparatus which exhausts electric power of batteries in the apparatus.  
         [0004]     2. Description of the Related Art  
         [0005]     In recent years, a capsule endoscope equipped with an imaging function and a radio function has appeared in the endoscope field. The capsule endoscope is moved in internal organs such as a stomach and a small intestine (or in body cavities) with peristaltic motion thereof to sequentially perform imaging in the body cavities using the imaging function in an observation period during which the capsule endoscope is swallowed into a subject as a tested body for observation (examination) and is naturally discharged from the living body as the subject.  
         [0006]     Image data imaged in the body cavities by the capsule endoscope in the observation period of movement in these internal organs is sequentially transmitted to an external device provided outside the subject by the radio function such as radio communication and is then stored in a memory provided in the external device. Electric power is supplied to drive each electric portion for ensuring the imaging function and the radio function. The driving will be hereinafter called driving of the capsule endoscope. The subject carries the external device having the radio function and the memory function. The subject can be freely moved in the observation period during which the capsule endoscope is swallowed and discharged. After observation, a doctor or a nurse can display the images in the body cavities on a display device such as a display based on the image data stored in the memory of the external device to perform diagnosis.  
         [0007]     As such a capsule endoscope, there is one of a swallow type as shown in International Publication Pamphlet WO01/35813. There has been proposed a capsule endoscope having in its inside a reed switch turned on and off by an external magnetic field to control driving of the capsule endoscope and housed in a package including a permanent magnet supplying the external magnetic field. The reed switch provided in the capsule endoscope maintains the off state in an environment in which a magnetic field above a fixed strength is given and is turned on by the lowered strength of the external, magnetic field. The capsule endoscope housed in the package is not driven. At swallow, the capsule endoscope is taken out from the package to be away from the permanent magnet. The capsule endoscope is not affected by a magnetic force. The reed switch is in the on state to start driving the capsule endoscope. In such construction, driving of the capsule endoscope housed in the package can be prevented. The capsule endoscope taken out from the package performs imaging by the illumination function and the imaging function and transmits an image signal by the radio function.  
       SUMMARY OF THE INVENTION  
       [0008]     A body-insertable apparatus according to one aspect of the present invention includes a function execution unit which executes a predetermined function in a subject into which the body-insertable apparatus is introduced; an electric power storage unit which stores driving electric power for driving the function execution unit; a detection unit which detects electric power supplied from the electric power storage unit; and an exhaustion unit which is provided to be separated from the function execution unit and exhausts the electric power of the electric power storage unit based on a detection result of the detection unit.  
         [0009]     The above and other objects, features, advantages and technical and industrial significance of this invention will be better understood by reading the following detailed description of presently preferred embodiments of the invention, when considered in connection with the accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]      FIG. 1  is a system concept view showing the concept of a radio type intra-subject information obtaining system according to the present invention;  
         [0011]      FIG. 2  is a block diagram showing the inner construction in a capsule endoscope according to a first embodiment shown in  FIG. 1 ;  
         [0012]      FIG. 3  is a circuit diagram showing the circuit construction of a system control circuit according to the first embodiment shown in  FIG. 2 ;  
         [0013]      FIG. 4  is a block diagram showing the inner construction of a communication device according to the first embodiment shown in  FIG. 1 ; and  
         [0014]      FIG. 5  is a circuit diagram showing an essential portion of the circuit construction of a system control circuit according to a second embodiment shown in  FIG. 2 . 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0015]     Exemplary embodiments of a body-insertable apparatus according to the present invention will be described in detail below with reference to the drawings of FIGS.  1  to  5 . In the following drawings, the same components as those of  FIG. 1  are indicated by identical reference numerals for convenience of the description. The present invention is not limited to these embodiments and various modified embodiments can be made in the scope without departing from the subject matter of the present invention.  
       First Embodiment  
       [0016]      FIG. 1  is a system concept view showing the concept of a wireless in-vivo information obtaining system according to the present invention. In  FIG. 1 , the wireless in-vivo information obtaining system has a capsule endoscope  2  of a swallow type as a body-insertable apparatus which is introduced into the body cavities of a subject  1 , and a communication device  3  as an extra-corporeal device arranged outside the subject  1  and radio-communicating various pieces of information between the communication device  3  and the capsule endoscope  2 . The wireless in-vivo information obtaining system also has a display device  4  performing image display based on data received by the communication device  3 , and a portable recording medium  5  performing input and output of data between the communication device  3  and the display device  4 .  
         [0017]     As shown in the block diagram of  FIG. 2 , the capsule endoscope  2  has a light emitting diode (LED)  20  as an illuminating unit for illuminating an examined portion in the body cavities of the subject  1 , an LED driving circuit  21  as first driving means for controlling the driven state of the LED  20 , a charge-coupled device (CCD)  22  as obtaining means for imaging an image in the body cavities (in-vivo information) as a reflected light from a region illuminated by the LED  20 , a CCD driving circuit  23  as first driving means for controlling the driven state of the CCD  22 , an RF transmitting unit  24  modulating the imaged image signal to an RF signal, and a transmitting antenna unit  25  as radio transmitting means for radio-transmitting the RF signal output from the RF transmitting unit  24 . The capsule endoscope  2  also has a system control circuit  26  controlling the operation of the LED driving circuit  21 , the CCD driving circuit  23 , and the RF transmitting unit  24 . While the capsule endoscope  2  is introduced into the subject  1 , image data of the examined portion illuminated by the LED  20  is obtained by the CCD  22 . The obtained image data is converted to an RF signal by the RF transmitting unit  24  and is transmitted to the outside of the subject  1  via the transmitting antenna unit  25 .  
         [0018]     The capsule endoscope  2  further has a receiving antenna unit  27  as radio receiving means which can receive a radio signal transmitted from the communication device  3 ; a control signal detection circuit  28  detecting a control signal at a predetermined input level (e.g., reception strength level) from the signal received by the receiving antenna unit  27 ; and a battery  29  supplying electric power to the system control circuit  26  and the control signal detection circuit  28 .  
         [0019]     The control signal detection circuit  28  detects the contents of the control signal and outputs the control signal to the LED driving circuit  21 , the CCD driving circuit  23 , and the system control circuit  26  as needed. The system control circuit  26  has a function of distributing driving electric power supplied from the battery  29  to other components (function execution means).  
         [0020]      FIG. 3  is a circuit diagram showing the circuit construction of the system control circuit according to a first embodiment shown in  FIG. 2 . In  FIG. 3 , the battery  29  is composed of plural (two in the first embodiment) button batteries  29   a  and  29   b.    
         [0021]     The system control circuit  26  has an FET (field-effect transistor)  26   a  whose source terminal is connected to the battery  29 , a diode  26   b  connected to the drain terminal of the FET  26   a,  a NOT circuit  26   c  connected to the output terminal of the diode  26   b , and a flip-flop  26   d  reset (R) by an output from the NOT circuit  26   c  and performing output (Q) to the gate terminal of the FET  26   a.  The output of the diode  26   b  is connected to an intra-capsule function execution circuit  30 . The flip-flop  26   d  is set (S) by an input from the above-described reed switch. In the present invention, a switch device can be used in place of a transistor such as an FET. In this embodiment, the imaging function, the illumination function, and the radio function (partially) provided in the capsule endoscope  2  are collectively called a function execution unit for executing predetermined functions. Specifically, the function execution unit for executing predetermined functions except for the system control circuit  26 , the receiving antenna unit  27 , and the control signal detection circuit  28  is generically called the intra-capsule function execution circuit  30  as needed.  
         [0022]     The system control circuit  26  has a flip-flop  26   e  to which an output of the NOT circuit  26   c  is input (CK), resistors  26   f  and  26   g  connectable in parallel with the button batteries  29   a  and  29   b,  respectively, and switch devices  26   h  and  26   i.  The switch devices  26   h  and  26   i  are in the off state while driving electric power is supplied from the button batteries  29   a  and  29   b  to the intra-capsule function execution circuit  30 . When no driving electric power is supplied to the intra-capsule function execution circuit  30 , the switch devices  26   h  and  26   i  are switched to the on state. In such manner, the operation of the switch devices  26   h  and  26   i  is controlled by the NOT circuit  26   c  and the flip-flop  26   e.  The switch devices  26   h  and  26   i  are switched to the on state by the output (Q) from the flip-flop  26   e.  The button batteries  29   a  and  29   b  are connected in parallel with the resistors  26   f  and  26   g,  respectively, to exhaust the electric power stored in the button batteries  29   a  and  29   b.    
         [0023]     The communication device  3  has a function of the transmission device as the radio transmission means for transmitting a start signal to the capsule endoscope  2 , and a function of the reception device as the radio reception means for receiving image data in the body cavities radio-transmitted from the capsule endoscope  2 .  FIG. 4  is a block diagram showing the inner construction of the communication device  3  according to the first embodiment shown in  FIG. 1 . In  FIG. 4 , the communication device  3  has transmission and reception clothes (e.g., transmission and reception jacket)  31  worn by the subject  1  and having plural receiving antennas Al to An and plural transmitting antennas B 1  to Bm, and an external device  32  performing signal processing of a transmitted and received radio signal. It should be noted that n and m indicate any number of antennas set as needed.  
         [0024]     The external device  32  has an RF receiving unit  33  performing predetermined signal processing such as demodulation to radio signals received by the receiving antennas A 1  to An and extracting image data obtained by the capsule endoscope  2  from the radio signals, an image processing unit  34  performing image processing necessary for the extracted image data, and a storage unit  35  for recording the image-processed image data, and performs signal processing of the radio signals transmitted from the capsule endoscope  2 . In this embodiment, the image data is recorded via the storage unit  35  to the portable recording medium  5 .  
         [0025]     The external device  32  also has a control signal input unit  36  generating a control signal (start signal) for controlling the driven state of the capsule endoscope  2 , and an RF transmitting unit circuit  37  converting the generated control signal to a radio frequency to output it. The signal converted by the RF transmitting unit circuit  37  is output to the transmitting antennas B 1  to Bm to be transmitted to the capsule endoscope  2 . The external device  32  further has an electric power supplying unit  38  having a predetermined capacitor or an AC power source adapter. Each component of the external device  32  uses electric power supplied from the electric power supplying unit  38  as a driving energy.  
         [0026]     The display device  4  displays an image in the body cavities imaged by the capsule endoscope  2  and has a configuration such as a workstation performing image display based on data obtained by the portable recording medium  5 . Specifically, the display device  4  may directly display an image by a CRT display and a liquid crystal display or may output an image to other medium like a printer.  
         [0027]     The portable recording medium  5  can be connected to the external device  32  and the display device  4 , and can output or record information when the portable recording medium  5  is inserted into and connected to both. In this embodiment, the portable recording medium  5  is inserted into the external device  32  to record data transmitted from the capsule endoscope  2  while the capsule endoscope  2  is moved in the body cavities of the subject  1 . After the capsule endoscope  2  is discharged from the subject  1 , that is, after imaging of the inside of the subject  1  is completed, the portable recording medium  5  is taken out from the external device  32  to be inserted into the display device  4 . The display device  4  reads the data recorded onto the display device  4 . The portable recording medium  5  has a CompactFlash (Registered Trademark) memory and can indirectly perform input and output of data between the external device  32  and the display device  4  via the portable recording medium  5 . Unlike the case that the external device  32  and the display device  4  are directly connected by cable, the subject  1  can be freely moved during photographing in the body cavities.  
         [0028]     Using the circuit diagram of  FIG. 3 , the operation of the capsule endoscope  2  will be described. In  FIG. 3 , the capsule endoscope  2  before being introduced into the subject  1  has in its inside a reed switch, not shown, turned on and off by an external magnetic field and is stored in the state that the capsule endoscope  2  is housed in a package including a permanent magnet supplying the external magnetic field. In this state, the capsule endoscope  2  is not driven.  
         [0029]     When the capsule endoscope  2  is taken out from the package at swallow, the capsule endoscope  2  away from the permanent magnet of the package is not affected by a magnet force. The flip-flop  26   d  is set (S) by an input from the reed switch. The set flip-flop  26   d  performs the output (Q) to the gate terminal of the FET  26   a.  The output (Q) flows an electric current between the source and drain terminals of the FET  26   a.  Electric power from the button batteries  29   a  and  29   b  is supplied via the diode  26   b  to the intra-capsule function execution circuit  30 .  
         [0030]     A voltage supplied from the button batteries  29   a  and  29   b  is “A”. Voltages consumed by the FET  26   a  and the diode are “B” and “C”, respectively. A voltage supplied to the intra-capsule function execution circuit  30  is A−(B+C)=X. An intermediate potential Y is set as a threshold value to the NOT circuit  26   c.  When the voltage X is larger than the intermediate potential Y, that is, (voltage X)&gt;(intermediate potential Y), the switch devices  26   h  and  26   i  are in the off state with no output from the NOT circuit  26   c.    
         [0031]     When the voltage X is equal to or smaller than the intermediate potential Y, that is, (voltage X)&lt;(intermediate potential Y), an output from the NOT circuit  26   c  resets the flip-flop  26   d  and the output from the NOT circuit  26   c  is input to the flip-flop  26   e.  When the flip-flop  26   d  is reset, no electric current is flowed between the source and drain terminals. No driving electric power is supplied to the intra-capsule function execution circuit  30 . When the output from the NOT circuit  26   c  is input, the flip-flop  26   e  performs the output (Q) to switch the switch devices  26   h  and  26   i  to the on state. The switch operation connects the button batteries  29   a  and  29   b  in parallel with the resistors  26   f  and  26   g,  respectively. The resistors  26   f  and  26   g  can exhaust the electric power stored in the button batteries  29   a  and  29   b.    
         [0032]     In this embodiment, when the voltage supplied from the button batteries is equal to or smaller than the predetermined intermediate potential, supply of the driving electric power to the intra-capsule function execution circuit is stopped. The electric power stored in the button batteries is exhausted by the resistors connected in parallel therewith. A phenomenon such as latchup due to the intermediate potential cannot occur at the load side of the function execution unit. Malfunction of the circuits in the intermediate potential state can be prevented.  
       Second Embodiment  
       [0033]      FIG. 5  is a circuit diagram showing an essential portion of the circuit construction of the system control circuit according to a second embodiment shown in  FIG. 2 . In  FIG. 5 , the battery  29  of the second embodiment has three button batteries  29   a  to  29   c  stacked in series and is grounded to a conductive substrate  29   d  provided in the capsule endoscope  2 .  
         [0034]     As in the first embodiment, the system control circuit according to the second embodiment has the FET  26   a , the diode  26   b , the NOT circuit  26   c,  the flip-flop  26   d,  and a flip-flop  26   e  connected to the button battery  29   a.  Further, the system control circuit according to the second embodiment has shape-memory members  29   e  to  29   g  made of conductive members arranged in positive pole cases of the button batteries  29   a  to  29   c  stacked in series, and resistors  29   h  to  29   j  arranged on the button batteries  29   b  and  29   c  and the substrate  29   d.    
         [0035]     The button battery  29   a  has, in its positive pole, heat coils  26   j  to  26   l  connectable in series therewith and a switch device  26   m.  The switch device  26   m  is in the off state while driving electric power is supplied from the button batteries  29   a  to  29   c  to the intra-capsule function execution circuit  30 . The switch device  26   m  is switched to the on state while no driving electric power is supplied to the intra-capsule function execution circuit  30 . In such manner, the operation of the switch device  26   m  is controlled by the NOT circuit  26   c  and the flip-flop  26   e . The switch device  26   m  is switched to the on state by the output (Q) from the flip-flop  26   e  to connect the button batteries  29   a  to  29   c  in series with the heat coils  26   j  to  26   l.    
         [0036]     When an electric current flows, the heat coils  26   j  to  26   l  generate heat above a predetermined temperature, i.e., at 40 to 45° C. slightly higher than the temperature of the subject. The shape-memory members  29   e  to  29   g  are made of a shape-memory alloy or a shape-memory resin which uses the predetermined temperature as a critical. temperature and is recovered to a memory shape above such a critical temperature. When the shape-memory members  29   e  to  29   g  are recovered to the memory shape, they are electrically connected to the resistors  29   h  to  29   j  arranged on the adjacent button batteries  29   b  and  29   c  and the substrate  29   d  to short-circuit the button batteries  29   a  to  29   c.  In the second embodiment, the resistors of the resistors  29   h  to  29   j  are adjusted to prevent an overcurrent from occurring in order to avoid heat generation due to the overcurrent flowed to the button batteries  29   a  to  29   c  with the short circuit. The resistors  29   h  to  29   j  are made of conductive members whose resistances are adjusted, e.g., of rubber or plastic.  
         [0037]     When the voltage X supplied from the intra-capsule function execution circuit  30  is equal to or smaller than the intermediate potential Y set by the NOT circuit  26   c,  an output from the NOT circuit  26   c  stops supply of driving electric power to the intra-capsule function execution circuit  30  and the flip-flop  26   e  performs the output (Q) to switch the switch device  26   m  to the on state. The switch operation connects the button batteries  29   a  and  29   b  in series with the heat coils  26   j  to  26   l . The heat coils  26   j  to  26   l  are heat generated at a predetermined temperature. By the heat generation, the shape-memory members  29   e  to  29   g  are recovered to the memory shape to be electrically connected to the resistors  29   h  to  29   j  for short-circuiting the button batteries  29   a  to  29   c.    
         [0038]     In this embodiment, when the voltage supplied from the button batteries is equal to or smaller than the predetermined intermediate potential, supply of the driving electric power to the intra-capsule function execution circuit is stopped. The button batteries are short-circuited via the resistors to exhaust the electric power stored in the button batteries. As in the first embodiment, malfunction of the circuits in the intermediate potential state can be prevented.  
         [0039]     In the present invention, the switch device and the resistors connectable in series are arranged between the button batteries  29   a  to  29   c  and the substrate  29   d  shown in  FIG. 5 . When the switch device is switched to the on state by the operation control of the flip-flop  26   e,  the button batteries  29   a  to  29   c  are electrically connected in series with the resistors to short-circuit the button batteries  29   a  to  29   c.  In this case, the switch device and the resistors are patterned to an insulating resin film. The resin film is bonded to the positive pole cases of the button batteries  29   a  to  29   c.  The contacts of the switch device and the resistors are electrically connected with the positive pole cases.  
         [0040]     In this case, as in the second embodiment, when the voltage supplied from the button batteries is equal to or smaller than the predetermined intermediate potential, the button batteries are short-circuited via the resistors to exhaust the electric power stored in the button batteries. Malfunction of the circuits in the intermediate potential state can be prevented. No heat occurs in the capsule endoscope. A few number of components can exhaust the electric power stored in the button batteries.  
         [0041]     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.