Abstract:
A method of transmitting images in a subject to an outside of the subject using a wireless signal is provided. The method including: (a) transmitting to the outside of the subject a first signal corresponding to a first image obtained using a first imaging device; (b) transmitting to the outside of the subject a second signal corresponding to a second image obtained using a second imaging device; and (c) repeating (a) and (b), where at least initiation of the transmitting the first signal and initiation of the transmitting the second signals is alternately performed

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is a continuation of U.S. application Ser. No. 11/186,587 filed on Jul. 21, 2005, which is a continuation of U.S. application Ser. No. 10/205,513, now U.S. Pat. No. 6,951,536, which claims benefit of Japanese Applications Nos. 2001-229952 filed on Jul. 30, 2001 and 2001-333125 filed on Oct. 30, 2001, the contents of each of which are incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to a capsule-type medical device and medical system for conducting, for example, examinations in somatic cavities with a capsule body incorporating an image pickup device.  
         [0004]     2. Description of the Related Art  
         [0005]     Capsule-type endoscopes, which are used to conduct, for example, examinations by inserting a capsule body shaped as a capsule into somatic cavities and lumens of human being or animals have recently been suggested.  
         [0006]     For example, the endoscope disclosed in Japanese Patent Application Laid-open No. H7-111985 comprises a spherical capsule whose shape was split in two.  
         [0007]     However, within the framework of such conventional technology, the two capsules were almost of the same size. Therefore, ability of advancing and easiness of swallowing were not sufficiently improved.  
         [0008]     Further, endoscopes have recently come into wide use in medical and industrial fields. For example, in case of endoscopic examinations in somatic cavity, an insertion member has to be inserted and the patient&#39;s pain is increased. A conventional example of a capsule-type endoscope shaped as a capsule to resolve this problem was disclosed in Japanese Patent Application Laid-open No. 2001-95755.  
         [0009]     However, because capsule-type endoscopes capture images while executing unidirectional movement in lumen portions in the body by utilizing peristalsis inside the body, in the conventional example, the images of the entire inner wall of lumen are difficult to be captured without a miss.  
         [0010]     On the other hand, Japanese Patent Application Laid-open No. 2000-342526 discloses an endoscope in which illumination and observations means are provided on the front and back ends of a long cylindrical member.  
         [0011]     In this case, observations can be conducted with two observation means with different observation directions. Therefore, the drawbacks of the above-described conventional examples can be overcome or eliminated. However, the problem is that because of a long cylindrical shape, the endoscope is difficult to move smoothly through curved portions and the significant patient&#39;s pain is increased.  
       SUMMARY OF THE INVENTION  
       [0012]     Accordingly, a capsule-type medical device, which is advanced through a digestive tract of a human being or animal for conducting an examination, therapy, or treatment is provided. The capsule-type medical device comprising: a plurality of capsule bodies; a soft linking unit which links the plurality of capsule bodies and has an outer diameter less than that of any of the capsule bodies; and a joining member which joins two or more of the plurality of capsule bodies in a prescribed position.  
         [0013]     Also provided is a method for examination, therapy, or treatment of the digestive tract of a human being by using a capsule-type medical device comprising a plurality of capsule bodies. The method comprising: swallowing the capsule-type medical device in a linear shape; advancing the capsule-type medical device entirely through the narrow lumen portion of the digestive tract; and joining at least two of the plurality of capsule bodies in the prescribed position at a predetermined portion of the digestive tract. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]      FIG. 1  illustrates the capsule-type endoscopic system of the first embodiment of the present invention;  
         [0015]      FIG. 2  is a sectional view illustrating the structure of the capsule-type endoscope of the first embodiment;  
         [0016]      FIG. 3  illustrates the capsule-type endoscope of the first embodiment, which moves from the stomach into the duodenum;  
         [0017]      FIG. 4  illustrates the structure and functions of the illumination device and observation device component of the first embodiment;  
         [0018]      FIG. 5  illustrates a part of the structure shown in  FIG. 4 ;  
         [0019]      FIG. 6  is a sectional view illustrating the structure of a part of the capsule-type endoscope which is a modification example of the first embodiment;  
         [0020]      FIG. 7  is a sectional view illustrating the structure of the capsule-type endoscope of the second embodiment of the present invention;  
         [0021]      FIG. 8  illustrates the state of examining the inside of a somatic cavity with the capsule-type endoscope of the second embodiment;  
         [0022]      FIG. 9  illustrates the state of recovering the endoscope with a recovery tool when the endoscope is blocked in an isthmus;  
         [0023]      FIG. 10  is a sectional view illustrating the first capsule portion in the modification example of the second embodiment;  
         [0024]      FIG. 11  is a perspective view, with a partial cut-out, of the structure of the capsule-type medical device of the third embodiment of the present invention;  
         [0025]      FIG. 12  is a sectional view illustrating the configuration of the main components of the capsule-type medical device of the first modification example of the third embodiment of the present invention;  
         [0026]      FIG. 13  illustrates the configuration of the main components of the capsule-type medical device of the second modification example of the third embodiment of the present invention;  
         [0027]      FIG. 14  illustrates the external appearance of the capsule-type endoscope of the fourth embodiment of the present invention;  
         [0028]      FIG. 15  illustrates the internal structure of one capsule body of the fourth embodiment of the present invention;  
         [0029]      FIG. 16A  and  FIG. 16B  explain the operation in the usage state of the capsule-type endoscope of the fourth embodiment;  
         [0030]      FIGS. 17A  to  17 D illustrate the sequence of operations in conducting the endoscopic examination according to the fourth embodiment;  
         [0031]      FIG. 18  is a block-diagram illustrating the configuration of the electric system of the external unit and display system of the fourth embodiment;  
         [0032]      FIG. 19  is a block-diagram illustrating a modification example of the configuration of the external unit of the fourth embodiment;  
         [0033]      FIGS. 20A  to  20 F are timing charts of illumination and image capturing conducted when the external unit shown in  FIG. 19  was used;  
         [0034]      FIG. 21  illustrates a modification example of the antenna configuration of the fourth embodiment;  
         [0035]      FIG. 22  is a perspective view illustrating a part of the capsule-type endoscope of the first modification example of the fourth embodiment;  
         [0036]      FIG. 23  illustrates the state in which the cover of capsule-type endoscope shown in  FIG. 22  was removed and the capsule body is installed in a rewriting device;  
         [0037]      FIG. 24  illustrates the internal structure of the capsule body shown in  FIG. 22 ;  
         [0038]      FIG. 25  illustrates the internal structure of the capsule body in the second modification example of the fourth embodiment;  
         [0039]      FIG. 26  schematically illustrates the capsule-type endoscope of the fifth embodiment of the present invention;  
         [0040]      FIG. 27  schematically illustrates the capsule-type endoscope of the first modification example of the fifth embodiment of the present invention;  
         [0041]      FIG. 28  schematically illustrates the capsule-type endoscope of the second modification example of the fifth embodiment of the present invention;  
         [0042]      FIG. 29  illustrates a part of internal configuration of the capsule-type endoscope of the sixth embodiment of the present invention;  
         [0043]      FIG. 30A  and  FIG. 30B  are timing charts for explaining the operation of controlling the intensity of light emission by an external signal, according to the sixth embodiment of the present invention;  
         [0044]      FIG. 31  explains a part of configuration of the capsule-type endoscope of the seventh embodiment of the present invention;  
         [0045]      FIG. 32  illustrates a part of configuration of the capsule-type endoscope of the modification example of the seventh embodiment of the present invention;  
         [0046]      FIG. 33  illustrates the structure of the antenna of the external unit of the eighth embodiment of the present invention;  
         [0047]      FIG. 34  illustrates the structure of the antenna of the first modification of the eighth embodiment of the present invention;  
         [0048]      FIG. 35  illustrates the structure of the antenna of the second modification of the eighth embodiment of the present invention;  
         [0049]      FIG. 36A  and  FIG. 36B  explain the structure of the capsule-type endoscopic system of the ninth embodiment of the present invention;  
         [0050]      FIG. 37  illustrates the structure of the capsule-type endoscope of the tenth embodiment of the present invention;  
         [0051]      FIG. 38  explains endoscopic examination of the tenth embodiment of the present invention;  
         [0052]      FIG. 39A  and  FIG. 39B  explain the structure of the capsule-type endoscope of the first modification of the tenth embodiment of the present invention;  
         [0053]      FIG. 40A  and  FIG. 40B  explain the structure of the capsule-type endoscope of the second modification of the tenth embodiment of the present invention;  
         [0054]      FIG. 41  illustrates the structure of the capsule-type endoscope of the third modification of the tenth embodiment of the present invention; and  
         [0055]      FIG. 42  explains the operation in a state in which two capsule bodies of the capsule-type endoscope of the third modification of the tenth embodiment of the present invention are combined.  
     
    
       [0056]     The above and other objects, features and advantages of the invention will become more clearly understood from the following description referring to the accompanying drawings.  
       DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0057]     The embodiments of the present invention will be explained hereinbelow with reference to the accompanying drawings.  
       First Embodiment  
       [0058]     FIGS.  1  to  6  illustrate the first embodiment of the present invention.  FIG. 1  illustrates the structure of the capsule-type endoscopic system of the first embodiment.  FIG. 2  illustrates the internal structure of the capsule-type endoscope of the first embodiment.  FIG. 3  illustrate an example of utilization relating to the movement from the stomach to the duodenum.  FIG. 4  illustrates the structure and functions of the illumination device and observation device components.  FIG. 5  illustrates a part of the structure shown in  FIG. 4 .  FIG. 6  illustrates the structure of a part of the capsule-type endoscope which is a modification example.  
         [0059]     As shown in  FIG. 1 , a capsule-type endoscopic system  1  of the first embodiment of the capsule-type medical device of the present invention is composed of a capsule-type endoscope  3  of the first embodiment, which is swallowed by a patient  2  and used for examination inside the somatic cavities, an external unit  5  disposed outside the body of patient  2  and equipped with an antenna  4  for wireless reception of image information picked up by the capsule-type endoscope  3 , and a personal computer (abbreviated as PC hereinbelow)  7  capable of taking in the images accumulated in the external unit  5  and displaying them on a monitor  6  by virtue of detachable connection of the external unit  5 . The PC  7  is composed by connecting a keyboard  9  for data input and the monitor  6  to a PC body  8  and is detachably connected to the external unit  5  with an USB cable  10  or the like.  
         [0060]      FIG. 2  illustrates the internal structure of the capsule-type endoscope  3  of the first embodiment.  
         [0061]     The capsule-type endoscope  3  comprises a first capsule  11   a  and a second capsule  11   b  as two capsule-like hard units of different diameters and a soft flexible tube  12  connecting the capsules and having a diameter less than the diameter of the two capsules  11   a ,  11   b , and has a structure in which the two capsules  11   a ,  11   b  are connected by the tube.  
         [0062]     In the first capsule  11   a , the cylindrical peripheral portion of a hard capsule frame  13  is water-tight sealed with a dome-like hard transparent cover  15  via a seal member  14 , this cover also covering the opening of capsule frame  13 . An image pickup device and an illumination device are housed inside the first capsule.  
         [0063]     An objective lens  16  constituting the image pickup device (observation device) is mounted on a light-shielding lens frame  17  and disposed opposite the transparent cover  15  in the central portion of the internal space covered with the dome-like transparent cover  15 . An image pickup element, for example, a CMOS image pickup device  18  is disposed in the image forming position of the objective lens.  
         [0064]     Furthermore, for example, white LEDs  19  are disposed as illumination devices in a plurality of places around the lens frame  17 , and the light emitted by the white LEDs  19  passes through the transparent cover  15  and illuminates the space outside thereof. Moreover, a drive circuit  20  for driving and inducing the emission of light by the white LEDs  19  and for driving the CMOS image pickup device  18 , and a controller  21  for controlling this drive circuit  20  and provided with a function of conducting signal processing with respect to the output signals of CMOS image pickup device  18  are disposed on the rear surface side of CMOS image pickup device  18 . The drive circuit and the controller are secured to the capsule frame  13 .  
         [0065]     Further, a connection socket  22  for connecting and securing one end of tube  12  is provided in the center of the end surface (back end surface) of capsule frame  13  on the side thereof opposite the transparent cover  15 . One end of tube  12  is water-tightly connected and secured to the connection socket.  
         [0066]     Moreover, one end of an electric cable  23  which is an electric connection member advanced the inside of the tube  12  is connected to the controller  21 , and the other end thereof is connected to the second capsule  11   b . The tube  12  is formed from a flexible tube made from polyurethane, poly(vinyl chloride), silicone, and the like.  
         [0067]     The length of tube  12  linking the first capsule  11   a  and the second capsule  11   b  is almost equal to, or greater than the length of the smaller first capsule  11   a.    
         [0068]     The electric cable  23  is curled, laid in a zigzag manner, or spirally wound inside the tube  12  so that practically no tension is applied to the electric cable  23  even when the shape of tube  12  is changed.  
         [0069]     In the second capsule  11   b  which is larger in size than the first capsule  11   a , the open end side of capsule frame  24 , which is a battery housing provided with a function of battery housing means, is detachably covered with a battery housing lid  26 , for example, via a seal member  25  inserted in the cylindrical surface part thereof. The external part of the battery housing lid  26  is covered with an elastic resin cover  28 , which serves as a protective cover, to a proximity of a connection socket  27  of tube  12  in the capsule frame  24 . The elastic resin cover  28  can be put on or taken off by using an elastic force thereof.  
         [0070]     A battery  29 , for example, a button-type battery, a transmission-receiving, circuit  30 , and an antenna  31  are enclosed in the capsule frame  24 . The transmission-receiving circuit  30  is electrically connected to the controller  21 , generates the signals which are to be transmitted, and demodulates the received signals. The antenna  31  is connected to the transmission-receiving circuit  30  and sends the image information picked up by the CMOS image pickup device  18  to the external unit  5  or receives control signals radio transmitted from the external unit  5 .  
         [0071]     The battery  29  serving as a power supply is connected so as to supply a drive power to the transmission-receiving circuit  29 , controller  21 , and drive circuit  20 .  
         [0072]     An external thread  32  is provided on the cylindrical side surface portion of the second capsule  11   b , and an internal thread for engaging with the external thread  32  is provided on the inner peripheral surface of battery housing lid  26 . Furthermore, a circular groove is provided on the cylindrical side surface portion of the second capsule  11   b , and a seal member  25  for waterproofing, for example, such as an O-ring, is housed therein, thereby water-tightly sealing the inside of the capsule between the seal member and the battery housing lid  26  which is brought in contact therewith under pressure.  
         [0073]     Furthermore, the other end of tube  12  is water-tightly secured, for example, with an adhesive to the connection socket  27  located in the central portion of capsule frame  24  on the side opposite the battery housing lid  26 .  
         [0074]     Moreover, the external unit  5  receives signals from the capsule-type endoscope  3  with the antenna  4 , and the image demodulated by an internal signal processing circuit (not shown in the figure) is displayed on a liquid-crystal monitor  5   a  provided in the external unit  5  and also compressed and stored in the internal nonvolatile memory or a small hard disk or the like.  
         [0075]     A control member  5   b  is provided in the external unit  5 . By operating the control member  5   b , it is possible to send a control signal in the form of electromagnetic wave from the antenna  4 , and if the capsule-type endoscope  3  receives this control signal, the controller  21  can vary the illumination interval of illumination device and the image capturing period of the image pickup device.  
         [0076]     For example, the capsule-type endoscope  3  usually conducts one cycle of illumination and image pickup within 2 seconds, but if control signals are once received with a short interval, one cycle of illumination and image pickup is conducted within 1 second. If the control signals with a short interval are received twice in a row, two cycles of illumination and image pickup are conducted within 1 second. Furthermore, if a cancel control signal is sent, the capsule-type endoscope  3  returns to the usual illumination and image pickup period.  
         [0077]     Furthermore, connecting the external unit  5  to PC  7  upon completion of endoscopic examination with the capsule-type endoscope  3  makes it possible to load the image data accumulated by the external unit  5  into the PC  7  and to display them with the monitor  6 .  
         [0078]     In the capsule-type endoscope  3  of such a configuration, the two capsules  11   a ,  11   b  one of which is smaller than the other are linked by a flexible tube  12 , and the image pickup device and illumination device are housed in the first capsule  11   a . Furthermore, the battery  29  serving as a power supply and the antenna  31  are housed in the larger second capsule  11   b , electric power is supplied to the image pickup device and illumination device via the electric cable  23  is passed through the inside of the tube  12 , and the image signals picked up by the image pickup device are transmitted to the outside from the antenna  31 .  
         [0079]     In this case, making one of the capsules  11   a ,  11   b  smaller than the other facilitates swallowing and makes advancing easier. Furthermore, housing the illumination device and image pickup device on the front end side, namely on the end side opposite to the one connected with the tube  12 , of the smaller first capsule  11   a  and illuminating zones ahead in the movement direction of capsule-type endoscope  3  allows to pick up images of the illuminated somatic cavities.  
         [0080]     Furthermore, the rear side of the smaller first capsule  11   a  is corner cut and a chamfer  34  is provided so as to obtain an inclined or spherical surface. Thus, the periphery of the surface connected to the tube  12  which is a soft part linking the hard units is chamfered to obtain a spherical or inclined shape.  
         [0081]     The outer periphery of the front portion of the larger second capsule  11   b , which is connected by the tube  12 , is also provided with a chamfer  35  to obtain an inclined or spherical shape improving the advancing ability. The chamfer  35  is made larger than the chamfer  34  on the back end side of the first capsule  11   a  to permit unobstructed passage.  
         [0082]     Further, the electric cable  23  is made longer than the tube  12  to follow the deformation of flexible tube  12 .  
         [0083]     The length of tube  12  is equal to or greater than the length of the smaller first capsule  11   a . Thus, providing a length exceeding the fixed value makes it easier to swallow the endoscope. When the length of tube  12  is within a range from the length almost equal to that of the smaller first capsule  11   a  to the length twice that, twisting or knotting of the soft linking unit is prevented.  
         [0084]     In case of endoscopic examination of patient  2  who swallows the capsule-type endoscope  3  of the above-described embodiment, as shown in  FIG. 1 , making the two capsules  11   a ,  11   b  different in size allows them to be smoothly and easily swallowed, when the endoscope is swallowed with the smaller end forward, and also permits the movement direction to be controlled, as shown in  FIG. 3 .  
         [0085]     As shown in  FIG. 3 , when the capsule-type endoscope  3  advances from a stomach  36 , through a pylorus  37 , to a duodenum  38 , the smaller first capsule  11   a  easily enters first, thereby allowing the movement direction and observation direction to be matched.  
         [0086]     The dome-like transparent cover  15  is provided on the front side of the smaller first capsule  11   a  so as to cover the front surface of this capsule, and this transparent cover  15  encloses the image pickup device and illumination device. The objective lens  16  constituting the image pickup device is fit into the light-shielding lens frame  17  for shielding the unnecessary light reflected from the inner side of the transparent cover  15  and protrudes forward beyond the illumination device. Thus, the light-shielding lens frame is provided around the observation device and the front surface of the light-shielding lens frame projects beyond the front surface of illumination device.  
         [0087]     Because of its shape, the capsule-type endoscope  3  conducts illumination and observation (image pickup) through the dome-like window. In this case, the reflection and back reflection of the illuminated light on the inner surface of the dome-like transparent cover  15  provided on the front surface of illumination device and observation device can occur with a high probability and the observed image can contain a ghost component or flare. For this reason, the function of the light-shielding lens frame  17  is of major importance.  
         [0088]     In the present embodiment, as shown in  FIG. 4 , when the height of lens frame  17  is represented by h and the distance between objective lens  16  and illuminating device is represented by s, the positional relationship of lens frame  17  and illumination device is set such as to prevent the light emitted from the illumination device and then reflected from the inner surface of transparent cover  15 , as completely as possible, from entering the objective lens  16 . In other words, the outer diameter and height of the light-shielding lens frame and the distance between the illumination device and observation device are set such as to substantially prevent the incidence of the unnecessary light such as the light emitted from the illumination device and then reflected from the inner surface of the dome-like observation window onto the observation device. For example, a part of the light emitted, as shown by the arrow, from one white LED  19  constituting the illumination device shown in  FIG. 4  is reflected by the inner surface of transparent cover  15 , but practically all the reflected light is prevented from entering the objective lens  16  located on the inner side of lens frame  17 , thereby ensuring the field of view created by the objective lens  16 .  
         [0089]     Furthermore, the light that passed through the inner surface of transparent cover  15  and was reflected by the outer surface thereof is also prevented as completely as possible from entering the objective lens  16 . As a result, random penetration of reflected light is substantially eliminated and observation performance is improved.  
         [0090]      FIG. 5  is an expanded view of the main part of the structure shown in  FIG. 4 , which illustrates the effective illumination of the view field range.  
         [0091]     As shown in  FIG. 5 , the range of field of view with respect to the observation object  39 , which is defined by the objective lens  16  installed in the lens frame  17  disposed in the center, can be illuminated with white LEDs  19  serving as illumination devices and disposed on both sides of the range of field of view. Here, for the sake of simplicity, the objective optical system is represented by a combination of objective lens  16  and lens frame  17 .  
         [0000]     In the figure:  
         [0092]     x: distance from the front surface of the objective optical system to the observation object  39 ,  
         [0093]     h: height of objective optical system (from the end surface of the white LED  19 ),  
         [0094]     d: diameter of the objective optical system,  
         [0095]     θ: view angle of the objective optical system,  
         [0096]     s: distance between the objective optical system and white LED  19 ,  
         [0097]     a: radius of field of view,  
         [0098]     b: illumination range.  
         [0099]     As shown in  FIG. 5 , a and b are set such that a≦b. As a result, the range of field of view can be effectively illuminated, without shielding the illumination light with the objective optical system.  
         [0100]     Here, 
 
 a=d/ 2 +x  tan θ
 
 b =( x/h )·( s−d/s )− d/ 2. 
 
         [0101]     The operation of the present embodiment will be described below.  
         [0102]     When somatic cavities of the patient  2  are examined with the capsule-type endoscope  3 , the battery  29  has to be housed as shown in  FIG. 2 . In this case, the portion where the battery  29  is housed can be detached by unscrewing. If the elastic resin cover  28  is removed and the battery housing lid  26  is removed by unscrewing, then a new battery  29  can be housed in an easy manner.  
         [0103]     When the capsule-type endoscope  3  is to be used, the patient  2  or doctor installs the battery  29  and screws the battery housing lid  26  into the capsule frame  24 , which is one part of the split battery housing unit, that is, assembles the battery housing unit, thereby turning the power supply ON and initiating the capturing of images or transmission and receiving of signals. The power supply can be thus turned ON in an easy manner, and no special switch is required. Conversely, when the capsule-type medical device is discarded, the battery can be easily removed, which is beneficial for the environment.  
         [0104]     Further, in the present embodiment, the battery  29  is placed in the second capsule  11   b . Therefore, if it is broken, problems can be associated with electric discharge or leakage. To prevent the breakage, the capsule is protected with the elastic resin cover  28 . Further, water-tight sealing with the seal member  25  such as an O-ring is implemented to prevent water and other body fluids from penetrating into the space where the battery  29  is housed.  
         [0105]     As shown in  FIG. 1 , the patient  2  can smoothly swallow the medical capsule  3  by inserting it into the mouth the first capsule  11   a  side first, this first capsule having a small outer diameter.  
         [0106]     The capsule-type endoscope  3  conducts illumination and image pickup with a constant cycle, and the picked-up image information is wireless transmitted from the antenna  31 . The image information is received by the external unit  5  and displayed on the liquid-crystal monitor  5   a  or stored.  
         [0107]     Therefore, the endoscopic examination crew can monitor the information with the liquid-crystal monitor  5   a . Further, since the outer diameter of the first capsule  11   a  is less than that of the second capsule  11   b  and the first capsule  11   a  advances easier than the second capsule  11   b , the first capsule  11   a  readily becomes ahead in the movement direction. In other words, when the endoscope advances from the stomach  36 , through the pylorus  37 , to the duodenum  38 , as shown in  FIG. 3 , it easily advances to the deep zones smaller first capsule  11   a  first.  
         [0108]     Furthermore, in this case since the illumination and image pickup devices are provided on the distal end of the first capsule  11   a , the image of somatic cavities in the movement direction can be picked up and images, which can be easily diagnosed in the same manner as diagnostic images obtained with the usual endoscope, can be also obtained.  
         [0109]     In another modification example, the below-described image pickup device may be used instead of the CMOS image pickup device.  
         [0110]     The image pickup device used herein employs a threshold voltage modulation image sensor (VMIS), which is the next-generation image sensor, possessing the merits of both the above-described CMOS image pickup device and the CCD (charge coupled device). The structure of this sensor is entirely different from that of the conventional CMOS sensor in which the light receiving unit is composed of 3-5 transistors and photodiodes. Thus, the VMIS has a structure employing a technology of modulating the threshold value of a MOS transistor with a charge generated by the received light and outputting the changes of the threshold value as the image signals.  
         [0111]     Such an image sensor features a combination of high quality of CCD and a high degree of integration and low power consumption of CMOS sensor.  
         [0112]     For this reason, it was employed in the disposable capsule-type endoscopes. Using such a feature makes it possible to realize a disposable endoscope (soft or hard) or a low-price endoscope. The voltage modulation image sensor (VMIS) can be used not only in such endoscopes, but also in usual videoscopes. In addition, such voltage modulation image sensor (VMIS) has the below-described excellent features.  
         [0113]     The structure is simple, with one transistor per one image sensor.  
         [0114]     The VMIS has excellent photoelectric characteristic such as high sensitivity and high dynamic range.  
         [0115]     Since the sensor can be fabricated by a CMOS process, a high degree of integration and low cost can be realized.  
         [0116]     There are sensors of a variety of types, such as QCIF (QSIF) size, CIF (SIF) size, VGA type, SVGA type, XGA type, and the like. In the capsule-type endoscope with wireless communication of the present invention, small sensors of “QCIF (QSIF) size” and “CIF (SIF) size” are especially preferred from the standpoint of wireless transmission speed, power consumption, and because they are easy to swallow.  
         [0117]      FIG. 6  illustrates a modification example of the first embodiment and shows part of the first capsule  11   a  of this modification example.  
         [0118]     In this modification example, a water-tight seal  40  is additionally implemented in white LEDs  19 , objective lens  16 , and lens frame  17  located inside the transparent cover  15  in the first capsule  11   a  shown in  FIG. 2 . In other words, a structure is employed in which the illumination device and observation device ensure water tightness for the hard unit with no dome-like observation window attached. Thus, the transparent cover  15  has a water-tight structure inside thereof on the front side, but even when cracks appear in the transparent cover  15  and it loses the waterproofing function thereof, using the water-tight seal  40  provides a water-tight structure for the entire surface facing the transparent cover  15  inside the transparent cover  15  so as to ensure electric insulation preventing the permeation of water into the electric system, such as the internal drive circuit  20 . The side surface portion is sealed with the seal member  14  in the same manner as shown in  FIG. 2 .  
         [0119]     With such a structure no water permeates into the electric system located inside the transparent cover  15  and electric insulation properties can be maintained even when cracks appear in the cover and it loses the waterproofing function thereof.  
         [0120]     The present embodiment has the following effects.  
         [0121]     Swallowing is facilitated by splitting one capsule in two to decrease the size thereof and making one of the resulting capsules less than the other. In other words, easiness of swallowing can be improved. Furthermore, changing the size of the capsules readily matches the movement direction with the observation direction. In other words, the observation ability can be improved.  
         [0122]     Further, adjusting the arrangement of the objective optical system and also the illumination and transparent cover  15  reduces random penetration of reflected light. In other words, the observation ability can be improved.  
         [0123]     Moreover, the power supply ON/OFF and battery replacement can be conducted in an easy manner. The endoscope is easy to handle and environment-friendly.  
         [0124]     Since waterproofing of inner circuits is maintained even when cracks appear in the transparent cover, accidents are prevented.  
         [0125]     In another modification example of the present embodiment, the front surface of the objective lens  16  of the lens frame  17  may be brought in contact with the inner surface of the transparent cover  15 . In this case, the transparent cover  15  has high resistance to deformation even when a large external force is applied thereto.  
         [0126]     In other words, since the objective lens  16  or lens frame  17  is arranged so as to be in contact with the transparent cover  15 , the transparent cover  15  is not deformable nor rupturable and, therefore, the strength can be increased.  
       Second Embodiment  
       [0127]     The second embodiment of the present invention will be described hereinbelow with reference to FIGS.  7  to  10 .  
         [0128]      FIG. 7  is a sectional view illustrating a capsule-type endoscope  2 B of the second embodiment of the present invention. This capsule-type endoscope  2 B comprises three capsules  41   a ,  41   b ,  41   c  and flexible tubes  42   a  and  42   b  linking the adjacent capsules  41   a ,  41   b  and the adjacent capsules  41   b ,  41   c.    
         [0129]     In this case, the first capsule  41   a  and third capsule  41   c  disposed on both ends have almost the same outer diameter, whereas the second capsule  41   b  disposed in the center with respect thereto has a larger outer diameter.  
         [0130]     Furthermore, the first capsule  41   a  and third capsule  41   c  have a structure similar to that of the first capsule  11   a  of the first embodiment, and the second capsule  41   b  has a structure similar to that of the second capsule  11   b.    
         [0131]     In the first capsule  41   a , a cylindrical permanent magnet  43   a  is provided to surround the cylindrical peripheral portion of a capsule frame  13   a  and the opening of capsule frame  13   a  is covered with a dome-like transparent cover  15   a . The circumferential part of this opening is water-tightly fixed with a waterproofing adhesive  44   a , and an image pickup device and an illumination device are housed inside thereof. A ferroelectric substance producing a strong magnetic force may be used instead of the permanent magnet  43   a.    
         [0132]     An objective lens  16   a  constituting the image pickup device (observation device) is mounted on a light-shielding lens frame  17   a  and disposed opposite the transparent cover  15   a  in the central portion of the internal space covered with the dome-like transparent cover  15   a . An image pickup element, for example, a CMOS image pickup device  18   a  is disposed in the image forming position of the objective lens. For example, the objective lens  16   a  is disposed so that the outer surface thereof is in contact with the inner surface of transparent cover  15   a.    
         [0133]     Furthermore, for example, white LEDs  19   a  are disposed as illumination devices in a plurality of places around the lens frame  17   a , and the light emitted by the white LED  19   a  passes through the transparent cover  15   a  and illuminates the space outside thereof.  
         [0134]     Moreover, a drive circuit  20   a  for driving and inducing the emission of light by the white LEDs  19   a  and for driving the CMOS image pickup device  18   a , and a controller  21   a  for controlling this drive circuit  20   a  and provided with a function of conducting signal processing with respect to the output signals of CMOS image pickup device  18   a  are disposed on the rear surface side of CMOS image pickup device  18   a . The drive circuit and the controller are secured to the capsule frame  13   a.    
         [0135]     As shown in  FIG. 6 , a water-tight seal  40   a  is implemented on the inner side of the transparent cover  15   a , and the electric system such as the drive circuit  20   a  and the like can be maintained in an electrically insulated state by the water-tight seal  40   a  even when cracks appear in the transparent cover  15   a  and water tightness provided by the portions covered with the transparent cover  15   a  is lost.  
         [0136]     Further, a connection socket  22   a  for connecting and securing one end of a tube  42   a  is provided in the center of the end surface of capsule frame  13   a  on the side thereof opposite the transparent cover  15   a . One end of the tube  42   a  is water-tightly connected and secured to the connection socket.  
         [0137]     Moreover, one end of an electric cable  23   a  which is passed through the inside of the tube  42   a  via the opening of a disk-like latch  45   a  is connected to the controller  21   a , and the other end thereof is connected to the second capsule  41   b.    
         [0138]     The latch  45   a  is connected to a latch  47   a  of the second capsule  41   b  via a linking metallic wire  46   a  inserted into the tube  42   a  and provides free bendability for the flexible tube  42   a , so as to prevent disrupting the linkage between capsules  41   a  and  41   b.    
         [0139]     An electric cable  23   a  is, for example, wound around the linking metallic wire  46   a  and inserted into the tube  42   a . A chamfer  34   a  is formed on the rear peripheral portion of the first capsule  41   a  by cutting it at an angle or corner cutting so as to obtain a spherical shape.  
         [0140]     The third capsule  41   c  has a similar structure. The components assigned with the reference symbol (a) that were explained in describing the first capsule  41   a  are now assigned with the reference symbol (c) and the explanation thereof is omitted.  
         [0141]     In the second capsule  41   b  which is larger in size than the first and third capsules  41   a ,  41   c , a seal member  25  is inserted, for example, into the cylindrical side surface of a capsule frame  24  serving as battery housing means and the end side thereof which is opened toward the third capsule  41   c  is detachably covered with a battery housing lid  48 .  
         [0142]     Connection sockets  27   a ,  27   c  for connecting and securing the tubes  42   a ,  42   b  are provided in the center of respective end surfaces of the capsule frame  24  and the battery housing lid  48 , and the tubes  42   a ,  42   b  are water-tightly connected and fixed, for example, with a waterproofing adhesive.  
         [0143]     Further, the outer peripheral portions of the batteries housing the lid  48  and the capsule frame  24  are covered with an elastic resin cover  49  up to the vicinity of connection sockets  27   a ,  27   c.    
         [0144]     The capsule frame  24  encloses, for example, a button-type battery  29 , a transmission-receiving circuit  30 , and an antenna  31 . The transmission-receiving circuit  30  is electrically connected to controllers  21   a ,  21   c , generates signals to be transmitted, and demodulates the received signals. The antenna  31  is connected to the transmission-receiving circuit  30  and sends the image information captured by the CMOS image pickup devices  18   a ,  18   c  to the external unit (not shown in the figure) or receives control signals wireless transmitted from the external unit.  
         [0145]     The battery  29  is connected so as to supply drive electric power to the transmission-receiving circuit  30 , controllers  21   a ,  21   c , and drive circuits  20   a ,  20   c.    
         [0146]     An external thread  32  is provided on the cylindrical side surface of the second capsule  41   b , and an internal thread, which is to be engaged with the external thread  32 , is provided on the inner peripheral surface of the battery housing lid  48 . Further, a circumferential groove is provided on the cylindrical side surface of the second capsule  41   b  and a seal member  25  such as an O-ring is housed therein, thereby water-tightly sealing the inside of the capsule between the seal member and the battery housing lid  48  which is brought in contact therewith under pressure.  
         [0147]     In the capsule-type endoscope  2 B of such a structure, three capsules  41   a ,  41   b ,  41   c  obtained by splitting into three portions are linked by the flexible tubes  42   a ,  42   b . In this case, both end capsules  41   a ,  41   c  are of almost the same size, and the central capsule  41   b  is larger than the two end capsules  41   a ,  41   c.    
         [0148]     The two end capsules  41   a ,  41   c  are provided with an illumination device, image pickup device, drive circuits used for illumination and image pickup devices, and a processing circuit for the image pickup device. The central capsule  41   b  is provided with the battery  29 , transmission-receiving circuit  30 , and antenna  31 , and various functions of the two end capsules  41   a ,  41   c  commonly use the battery  29  and transmission-receiving circuit  30  of the central capsule.  
         [0149]     Further, exchange of electric power and signals between the three capsules  41   a ,  41   b ,  41   c  is conducted by electric cables  23   a ,  23   c  located inside the flexible tubes  42   a ,  42   b . Linking metal wires  46   a ,  46   b  are passed through the inside of the tubes  42   a ,  42   b  so that the tubes  42   a ,  42   b  can be freely bent without disrupting the connection of capsules  41   a ,  41   b  and  41   b ,  41   c.    
         [0150]     Further, chamfers  35   a ,  35   b  larger than the above-described chamfers  34   a ,  34   c  are formed in the elastic resin cover  49 , which serves as a protective cover, in the corner portion facing the first capsule  41   a  and the corner portion facing the third capsule  41   c , respectively.  
         [0151]     The operation of this embodiment will be described below.  
         [0152]     Since the size of the two end capsules  41   a ,  41   c  is smaller than that of the central capsule  41   b , any of the two end capsules moves first in a somatic cavity  50 , as shown in  FIG. 8 . Therefore, zones ahead and behind in the movement direction can be observed with the two end capsules  41   a ,  41   c , each being provided with the illumination and image pickup devices. When the endoscope moves leftward, as shown in  FIG. 8 , the capsule  41   a  illuminates the zone ahead and picks up the images therefrom, and the capsule  41   c  illuminates the zone behind and picks up the images therefrom. The reverse is the case when the endoscope moves rightward.  
         [0153]     In the present embodiment, cylindrical permanent magnets  43   a ,  43   c  or magnetic substance is provided in both end capsules  41   a ,  41   c . As shown in  FIG. 9 , the permanent magnets  43   a ,  43   c  or magnetic substance makes it possible to recover the endoscope easily with a recovery tool  55  provided with a permanent magnet  54  at a front end of a cord-like member  53  when the capsule-type endoscope  2 B is stuck and cannot advance through an isthmus  51  in the somatic cavity  50  and has to be recovered.  
         [0154]     In other words, when the front end of the recovery tool  55  is brought close to the capsule-type endoscope  2 B, the permanent magnet  54  is attracted to the permanent magnet  43   a  or  43   c  due to a magnetic force acting between the permanent magnet  54  at the front end of recovery tool  55  and the permanent magnet  43   a  or  43   c  at the capsule-type endoscope  2 B. The capsule-type endoscope  2 B can be then easily pulled out, that is, recovered by pulling out the recovery tool  55 .  
         [0155]     The above explanation is related to the recovery operation, but the permanent magnets  43   a ,  43   c  or magnetic substance can be also used for remotely controlling the position or orientation of the capsule-type endoscope  2 B inside a somatic cavity by an external magnetic field.  
         [0156]     The effect of the present embodiment will be described below.  
         [0157]     Of the three above-described hard units, the outer diameter or length of the two end hard units is smaller than that of the hard unit other than the two end units. In particular, splitting a capsule in three decreases the size of capsule body and makes it easy to swallow the capsule. Thus, easiness of swallowing can be improved. In this case, swallowing can be made even more easier by decreasing the size of the capsules  41   a ,  41   c  located on both sides of central capsule  41   b . The outer diameters or lengths of the two end hard units are almost the same.  
         [0158]     Since the illumination devices and image pickup devices are provided in capsules  41   a ,  41   c  at the both sides, the observation direction can be the same as the movement direction and zones ahead and behind in the movement direction can be observed at the same time. Therefore, observation performance is improved. Further, since the size of capsules  41   a ,  41   c  located on both sides of the central capsule  41   b  is decreased, movement is facilitated.  
         [0159]     Further, since the power supply function and signal transmission and receiving function are made common for a plurality of illumination devices and image pickup devices, the number of components can be decreased, which is beneficial for size reduction. In other words, size can be reduced and easiness of swallowing can be improved. The function of control unit may be also made common.  
         [0160]     Further, providing the cylindrical permanent bodies  43   a ,  43   c  or magnetic substance allows the recovery or magnetic guidance. The recovery is facilitated and operability is improved.  
         [0161]      FIG. 10  illustrates a part of the first capsule  41   a  as a modification example of the present embodiment.  
         [0162]     One end of a linking metal wire  46   a  located inside the tube  42   a  connecting the capsules  41   a ,  41   b , on the side of capsule  41   a , as shown in  FIG. 10 , has a slidable latch structure.  
         [0163]     Thus, a latch  45   a  located inside the capsule  41   a  is disposed so that it is free to slide forward and backward inside a tubular body (ring)  56   a  disposed between the rear surface of controller  21   a  and the inner surface of capsule frame  13   a.    
         [0164]     Further, in the present embodiment, a lens frame  17   a  is abutted with the inner surface of the transparent cover  15   a.    
         [0165]     The resulting effect is that the transparent cover  15   a  is reinforced and the resistance thereof to external forces is improved.  
         [0166]     Further, in the present embodiment, the linking metal wires  46   a ,  46   c  located inside the tubes  42   a ,  42   c  connecting the three capsules were separate from electric cables  23   a ,  23   c , but in a structure of yet another modification example, the electric cables  23   a ,  23   c  may also serve as the linking metal wires  46   a ,  46   c.    
         [0167]     The resulting effect is that the structure can be simplified.  
         [0168]     A structure may be also used in which one end of the linking metal wire is made slidable, as shown in  FIG. 10 , and the electric cables  23   a ,  23   c  also serve as the linking metal wires  46   a ,  46   c . In this case, a sliding latch  45   a  may be provided with an electric contact and electrically connected to the controller  21   a  via the tubular body  56   a.    
         [0169]     In yet another modification example, a VMIS may be used instated of the CMOS image pickup device.  
       Third Embodiment  
       [0170]     The third embodiment of the present invention will be described below with reference to FIGS.  11  to  13 .  FIG. 11  illustrates a capsule-type medical device  2 C which is the third embodiment of the present invention. Structural components identical to those of the first embodiment are assigned with the same reference symbols and the explanation thereof is omitted.  
         [0171]     The capsule-type medical device  2 C has a structure in which a variety of sensor means  61  such as a pH sensor, optical sensor, temperature sensor, pressure sensor, blood sensor (hemoglobin sensor), and the like are provided, for example, as in the first capsule  11   a , for example, in the capsule-type endoscope  2  of the first embodiment.  
         [0172]     Various sensor means  61  are secured to the outer member of the capsule, such as the transparent cover  15 , so that sensing zone of sensor means  61  is exposed to the outside and the inside of the capsule is maintained in a water-tight state. Otherwise, the structure is the same as in the first embodiment.  
         [0173]     Data such as chemical parameters (pH value) of body fluids, brightness inside a somatic cavity, temperature of various organs, pressure applied by the inner surface of somatic cavities to the outer surface of the capsule when the capsule advances therethrough, amount of hemoglobin in various organs (presence of hemorrhage) are obtained from the sensing zones. The data obtained are temporarily accumulated in a memory (not shown in the figures) located inside the capsule and then transmitted by the transmission-receiving circuit  30  and antenna  31  to a receiver such as the external unit  5  located outside the body. By comparing the data obtained by the receiver with the standard values, the medical crew, such a doctor or nurse, can externally establish the presence of abnormalities, such as disease or hemorrhage, and to determine the capsule advancing position or state.  
         [0174]     In particular, diagnostics of gastroenterological diseases or physiological analysis can be conducted with high efficiency by painlessly establishing the pH value of hemoglobin level in digestive organs of the living body with the capsule-type medical device  2 C. Highly efficient examination can be conducted by providing a plurality of sensors according to the object of examination.  
         [0175]      FIG. 12  illustrates a part of the capsule-type medical device  2 D which is a modification example of the third embodiment. In the present embodiment, an ultrasound probe  71  is additionally provided in the second capsule  11   b  of the first embodiment. In this case, for example, a battery housing lid  26  is formed with a material transmitting ultrasound waves, a sealed space is formed in the battery housing lid  26 , a rotary-type ultrasound oscillator  72  is housed inside this space, and the area around the oscillator is filled with a transfer medium  73 .  
         [0176]     The ultrasound oscillator  72  is rotated by a motor  74 . The elastic resin cover  28  of the external surface of the capsule around the ultrasound oscillator  72  functions as an acoustic lens of ultrasound oscillator  72 . The battery housing lid  26  is detachably secured to a capsule frame  24  with a screw  76 .  
         [0177]     The ultrasound oscillator  72  makes possible the ultrasound tomography inside the somatic cavities, driving and signal processing being conducted by the control circuit  75 . Data obtained are transmitted to the external receiver in the same manner as described above. As a result, diagnostics of the presence of abnormalities in the depth direction of deep portions of somatic cavities such as a small intestine can be conducted. If a structure is used with observation devices on both sides, then diagnostics of both the surface and deep portions in somatic cavities can be conducted. An ultrasound probe with an electronic scanning system rather than mechanical scanning system may be also used.  
         [0178]      FIG. 13  illustrates a capsule-type medical device  2 E of the second modification example. This capsule-type medical device  2 E is provided with treatment-therapy means.  
         [0179]     In the capsule-type medical device  2 E, a medicine compartment  81  and a body fluid compartment  82  are provided, for example, in the elastic resin cover  28  in the second capsule  11   b , for example, in the capsule-type endoscope  2  of the first embodiment.  
         [0180]     The medicine compartment  81  and body fluid compartment  82  have openings that are open on the outer surface of the capsule, and the openings are covered with soluble membranes  83 ,  84  composed of fatty acid membranes or the like that are digested by the liquid present in intestines or of gelatin consumed by gastric juice. A medicine  85  for treatment is enclosed in the medicine compartment  81 . Once the capsule-type medical device  2 E has arrived to the target location, the soluble membrane  83  is dissolved, the opening is opened, and the medicine  85  is directly administered. At the same time, body fluid can be sucked into the body fluid compartment  82 .  
         [0181]     Further, a linear actuator  88  for driving a syringe  87  so that it can be protruded is provided, for example, inside a part of transparent cover  15  in the first capsule  11   a , this syringe having a compartment  86  accommodating a hemostatic drug.  
         [0182]     Thus, once a hemorrhaging zone has been established by a blood sensor or observation device, usually a procedure can be employed by which the syringe  87  for injecting the hemostatic drug accommodated inside the capsule is projected in response to a signal from the external unit  5  located outside the body and a powdered drug or ethanol which is the hemostatic drug located inside the compartment  86  is sprayed over the hemorrhaging zone to stop bleeding.  
         [0183]     Embodiments composed by partially combining the above-described embodiments are also covered by the present invention.  
         [0184]     As described above, in accordance with the present invention, a capsule-type medical device which is advanced the inside of the somatic cavities and lumens of human being or animals for conducting examination, therapy, or treatment comprises at least two hard units and a soft linking unit which links the aforesaid plurality of the hard units and has a diameter less than that of any of the hard units, wherein one of the plurality of hard units is different in size from other hard units. Therefore, when the smaller hard unit is swallowed first, the medical device can be easily swallowed and the smaller unit can easily be advanced the inside of the lumens.  
       Fourth Embodiment  
       [0185]     FIGS.  14  to  21  illustrate the first embodiment of the present invention.  FIG. 14  shows the external appearance of the capsule-type endoscope of the fourth embodiment.  FIG. 15  shows the internal structure of one of the capsule bodies.  FIGS. 16A and 16B  explain the operation in a state of usage.  FIGS. 17A, 17B ,  17 C, and  17 D illustrate the endoscopic examination procedure.  FIG. 18  is a block-diagram illustrating the structure of electric systems of the external unit and display system.  FIG. 19  is a block-diagram illustrating the structure of the external unit, which is a modification example of the fourth embodiment.  FIGS. 20A  to  20 F are timing charts illustrating timing diagrams of illumination and image pickup in the embodiment employing the external unit shown in  FIG. 19 .  FIG. 21  illustrates an example of antenna structure in another modification example of the fourth embodiment.  
         [0186]     As shown in  FIG. 14 , a capsule-type endoscope  101  of the fourth embodiment of the present invention is composed of a capsule-shaped first capsule body  102 A and a second capsule body  102 B, each containing an image pickup device, and a soft thin strap  103  connecting back end sides of the two capsule bodies  102 A,  102 B.  
         [0187]     In the present embodiment, the first capsule  102 A and the second capsule  102 B have the same structure. As an example,  FIG. 15  shows the inner structure of the second capsule  102 B.  
         [0188]     In the second capsule  102 B the front surface side of the body that has an almost cylindrical shape and is semi-spherically closed on the back end side thereof is covered with a semi-spherical transparent cover  105   b.    
         [0189]     An objective lens  106   b  is mounted in the center of the front surface portion of a body  104   b  inside the transparent cover  105   b , and a CMOS image pickup device  107   b  serving as a solid-state image pickup element is disposed in the image forming position of the lens.  
         [0190]     A plurality of LEDs  108   b  generating, for example, a white light are disposed around the objective lens  106   b . LEDs  108   b  are driven by a LED drive circuit  109   b  provided inside the body  104   b.    
         [0191]     The image of the examinee located inside a somatic cavity and illuminated by the LEDs  108   b  is formed by the objective lens  106   b  on the CMOS image pickup device  107   b  serving as an image pickup element and disposed in the image forming position of the lens. This image is photoelectrically converted by the CMOS image pickup device  107   b . The CMOS image pickup device  107   b  is driven by the drive signals from a driving and processing circuit  111   b , conducts signal processing by extraction and compression of image signal components with respect to photoelectrically converter output signals, and sends the signals to a transmission circuit  112   b.    
         [0192]     The transmission circuit  112   b  conducts high-frequency modulation of the input image signals, converts them into high-frequency signals, for example, with a frequency of 2.4 GHz, and emits electromagnetic waves from an antenna  113   b  to the outside. Power necessary for an operation of the transmission circuit  112   b , driving and processing circuit  111   b , and LED drive circuit  109   b  is supplied from a battery  114   b.    
         [0193]     Structural components of capsule body  102 A corresponding to structural components of capsule body  102 B explained with reference to  FIG. 15  will be explained below by using reference symbols (a) instead of reference symbols (b). Furthermore, structural components identical to those explained in  FIG. 15  are shown, for example, in  FIG. 24 .  
         [0194]     In the present modification, transmission from a transmission circuit  112   a  of capsule body  102 A and transmission circuit  112   b  of capsule body  102 B is conducted by slightly changing the transmission frequency. The signals are received by an external unit  116  (see  FIG. 17A ) disposed outside.  
         [0195]     In other words, electromagnetic waves transmitted by antennas  113   a  and  113   b  connected to the transmission circuit  112   a  of the capsule body  102 A and transmission circuit  112   b  of the capsule body  102 B, respectively, are received by the external unit  116  shown in  FIG. 17A .  
         [0196]      FIG. 17A  shows how a patient  117  swallows the capsule  101  when the endoscopic examination is begun. In this case, since the picked-up image signals are transmitted by the capsule-type endoscope  101  as electromagnetic waves, those electromagnetic waves are received by the external unit  116  mounted, for example, with a belt of the patient  117  at a waist line of the patient  117  and stored in the memory located inside the external unit  116 .  
         [0197]     When the endoscopic examination with the capsule-type endoscope  101  is completed, the external unit  116  is installed in a data capture unit  119  provided in a display system  118  shown in  FIG. 17B , and the image data accumulated in the external unit  116  can be imported in the display system  118  via the data capture unit  119 .  
         [0198]      FIG. 18  shows the configuration of the electric systems of the external unit  116  and display system  118 .  
         [0199]     The external unit  116  serving as a receiver comprises two antennas  121   a ,  121   b  receiving with good efficiency the electromagnetic waves of the frequency transmitted by the antennas  113   a ,  113   b  of the capsule bodies  102 A and  102 B, and the high-frequency signals induced in the antennas  121   a ,  121   b  are input in respective receiving circuits  122   a ,  122   b.    
         [0200]     The receiving circuits  122   a ,  122   b  are controlled by respective control circuits  123   a ,  123   b , and the control circuits  123   a ,  123   b  demodulate the high-frequency signals received by the receiving circuits  122   a ,  122   b  and conduct control so that those signals are successively stored in a memory  124 .  
         [0201]     The memory  124  is composed of a hard disk (abbreviated as HDD in the figure). The memory  124  is connected to a connector  125 . When the external unit  116  is installed in the data capture unit  119  shown in  FIG. 17B , a connector  125  is connected to a connector  126  of data capture unit  119 , as shown in  FIG. 18 .  
         [0202]     The connector  126  is connected to a memory  130  of display system  118 . The memory  130  is controlled by a control circuit  131 . The image data of observed images that are accumulated in the memory  124  of external unit  116  are developed and processed by an image processing circuit  132  via the memory  130  and stored, that is, recorded in a memory  133  which is a recording unit.  
         [0203]     The memory  133  is, for example, composed of a hard disk. The memory  133  is connected to a display circuit  134  conducting display processing, and image signals sent to the display circuit  134  are displayed by a display unit  136  conducting display of images as captured images via a comparison circuit  135  conducting comparison. The comparison circuit  135  is connected to a disease image database (abbreviated as DB)  137 , compares the images from the disease image database  137  with the captured image, retrieves a similar past disease image, and simultaneously displays it on the display unit  136  as the DB image.  
         [0204]     Furthermore, the control circuit  131  is connected to a console  138  such as a keyboard, and the command to capture images, to input patient data, to input diagnostic results, and the like are conducted from the console  138 .  
         [0205]     A specific feature of this embodiment, as shown in  FIG. 14 , is that the back ends of the two capsule bodies  102 A,  102 B, which are opposite to the front ends covered with transparent covers  105   a ,  105   b  are connected with a flexible strap  103  that has a width sufficiently less than that of the outer diameter of those capsule bodies  102 A,  102 B and such a structure allows for illumination and image pickup in mutually opposite directions.  
         [0206]     The operation relating to this embodiment will be described below.  
         [0207]     When endoscopic examination is conducted, the external unit  116  is attached to the waste of the patient  117 , for example, as shown in  FIG. 17A , and the patient  117  is asked to swallow the capsule-type endoscope  101 .  
         [0208]     The capsule-type endoscope  101 , for example, after the preset time, conducts illumination and image pickup, the picked-up image signals are transmitted from the antenna  113   a ,  113   b , and the external unit  116  receives the transmitted image signals and stores them in the memory  124 .  
         [0209]      FIGS. 16A and 16B  show how the images of the inside, for example, of a large intestine  140  are picked up with the capsule-type endoscope  101 .  
         [0210]     In the present embodiment, the two capsule bodies  102 A,  102 B are connected by the thin flexible strap  103 . Therefore, even when examination is conducted inside a lumen, for example, a right colon curve, as shown in  FIG. 16A , the endoscope can be freely bent in strap  103 . Therefore, the endoscope can smoothly advance the inside of the lumen, similarly to a single-capsule-type endoscope. Therefore, examination can be conducted without causing paint or discomfort to the patient  117 .  
         [0211]     Furthermore, in the present embodiment, the capsule bodies  102 A,  102 B have a structure such that the sides opposite to the back ends linked by the strap  103  serve as illumination and image pickup sides. Therefore, for example, as shown in  FIG. 16A , there may be instances when a portion  140  shown by dotting becomes a dead zone whose image cannot be picked up by the capsule body  102 B, which is located in the zone ahead in the movement direction, due to half-moon folds. However, following this state, as shown in  FIG. 16B , illumination and image pickup with the illumination and image pickup devices of the other capsule  102 A is conducted from the direction opposite to that of the preceding capsule  102 B, and the image of the zone that was a dead zone for the preceding capsule can be picked up with the succeeding capsule  102 A.  
         [0212]     Thus, with the present embodiment, the occurrence of portions becoming the dead zones is prevented to a greater degree than with a single capsule body and effective images can be obtained.  
         [0213]     Image signals obtained from two capsule bodies  102 A,  102 B are accumulated in the memory  124  of the external unit  116 , and after the capsule-type endoscope  101  is discharged to the outside of body, the external unit  116  is installed in the data capture unit  119  shown in  FIG. 17B  and the command signal of image capture is input from the console  138  of the display system  118 .  
         [0214]     In such a case, the image data accumulated in the memory  124  of the external unit  116  are transferred into the image processing circuit  132  via the memory  130  functioning as a buffer, subjected to processing such as development, and accumulated one by one as image data in memory  133 .  
         [0215]     The image data stored in the memory  133  can be successively displayed on the display device  136  if a display command is input from the console  138  by an operator.  
         [0216]     Furthermore, when a command input was made to pick up the image similar to the disease image that was accumulated in the disease database  137  with respect to the captured image, the image that was captured by the capsule-type endoscope  101  is displayed together with the disease image from the disease database  137  on the display surface of display device  136 , as shown in  FIG. 17C . In this state, the control circuit  131  shown in  FIG. 18  conducts a comparative processing such as pattern matching of the captured image and the disease image read out from the disease database  137  with the comparison circuit  135  and makes a decision as to whether there is a similarity exceeding the preset ratio. If a decision is made that there is a similarity exceeding the preset ratio, this image together with several adjacent images are linked to the data of disease database  137  and stored in the memory  133 .  
         [0217]     Then, only the images that can be related to a disease are extracted from all of the captured images and stored, for example, in an image extraction folder of the memory  133 .  
         [0218]     As shown in  FIG. 17D , the operator then conducts command input from the console  138  so as to display the extracted image on the display device  136 . As a result, the images stored in the image extraction folder are displayed successively and the operator can conduct final diagnostics with good efficiency. Thus, using the database to assist the diagnostics allows the diagnostics to be half automated and makes possible a significant reduction of time spent by the doctor on examination.  
         [0219]     With the present embodiment, the illumination devices and image pickup devices are provided in both capsules. Therefore, the observation direction can be the same as the movement direction and observations can be simultaneously conducted ahead and behind in the movement direction. As a result, the endoscope can be moved more smoothly inside curved lumens in a body than in the conventional examples and images can be picked up without causing strong pain in the patient, and from different directions, more specifically, from the movement direction and the direction opposite thereto. Therefore, high-quality images can be obtained and the number of occurring dead zones is small. Furthermore, a set of images captured inside the body can be obtained and, thus, the operator saves such a time of picking up images while inserting the endoscope.  
         [0220]      FIG. 19  illustrates the structure of a modification example of the external unit  116 .  
         [0221]     The external unit  116  shown in  FIG. 18  comprised the two antennas  121   a ,  121   b , receiving circuits  122   a ,  122   b , and control circuits  123   a ,  123   b . In the present modification example, the external unit comprises single antenna  121 , a receiving circuit  122 , and a control circuit  123 .  
         [0222]     Further, in the present modification example, as shown in  FIGS. 20A  to  20 F, the timings at which the transmission circuits  112   a ,  112   b  transmit the images obtained by illumination and image pickup by two capsule bodies  102 A,  102 B are shifted by half a period (T/2) with respect to each other to avoid overlapping thereof.  
         [0223]     In other words, when the power supply of the two capsule bodies  102 A,  102 B is turned ON and they are set into the operation state, for example, a LED  108   a  of the capsule body  102 A is ignited for a short time (for example, 1/30 sec) and an image is picked up by the CMOS image pickup device  107   a  and transmitted by the transmission circuit  112   a  (almost within half a period, T/2).  
         [0224]     Once the transmission by the transmission circuit  112   a  has been completed, the LED  108   b  of the other capsule body  102 B is ignited for a short timer an image is picked up by the CMOS image pickup device  107   b  and transmitted by the transmission circuit  112   b . Once the transmission by the transmission circuit  112   b  has been completed, the LED  108   a  of the first capsule body  102 A is again ignited.  
         [0225]     With such an operation, the image signals transmitted by the transmission circuits  112   a ,  112   b  are received by one antenna  121 , received by the receiving circuit  122 , and stored in the memory  124 .  
         [0226]     In this case, when the transmission frequencies of the transmission circuits  112   a  and  112   b  are slightly different, they can be received with a sufficiently good efficiency by the same antenna  121 . Furthermore, based on the transmission frequency, the external unit  124  can decide which of the image pickup elements has picked up the image.  
         [0227]     Further, when the transmission circuits  112   a  and  112   b  transmit at the same frequency, transmission may be conducted as shown in  FIGS. 20A  to  20 F. In this case, the transmission may be conducted by adding an identification code, for example, to the header of the image which is to be transmitted.  
         [0228]     In this case, the identification code may be recognized by the external unit  116  and separated from the image data, followed by storage in the memory  124 , or the image data may be stored in the memory  124 , with the identification code attached thereto, and the identification code may be recognized and separated from the image data in the display system  118 .  
         [0229]      FIG. 21  shows an antenna of the modification example of external unit  116 . In the present modification example, the external unit  116  installed in a belt is connected with a connection cable  142  to a necktie-type antenna row  144  located on a shirt  143  that is worn by the patient  117 . This necktie-type antenna row  144  is detachably secured to the shirt  143  with a button  145 .  
         [0230]     The necktie-type antenna row  144  thus hangs down from the neck of the patient  117 , and the antenna of the most intensive electromagnetic wave received among a plurality of antennas  144   a  constituting the antenna row  144  is used.  
         [0231]     With the present modification example, the installation can be conducted in an easy manner, without intensifying the pressure on the patient  117 . Further, a plurality of antennas  144   a  are arranged in the vertical direction and located in the vicinity of the center in the width direction of the body of patient  117 . Therefore, as the capsule-type endoscope  101  descends by peristalsis, since a plurality of antennas  144   a  are present along this direction, signals can be effectively received by the closest antenna  144   a.    
         [0232]     The first modification example of the present embodiment will be described below with reference to  FIG. 22 .  
         [0233]     In the capsule-type endoscope  101 B of modification example shown in  FIG. 22 , the external portion of the capsule body  102 A shown in  FIG. 14  can be removed as a cover  146 . An electrode  148  of a communication port  147  is exposed in the back end of a capsule body  102 A′ from which the cover  146  has been removed.  
         [0234]     As shown in  FIG. 23 , the back end of the capsule body  102 A′ from which the cover  146  has been removed is installed in a connector socket  149   a  of a rewriting unit  149 , and the operation program located inside the capsule body  102 A′ can be changed by manipulating the input keys  150  of the rewriting unit  149 .  
         [0235]      FIG. 24  illustrates the rewriting unit  149  and the internal structure of the capsule body  102 A′ in this case, that is, when the cover  146  has been removed. In the fourth embodiment, the capsule body  102 A′ additionally comprises a timing control circuit for conducting timing control or a timing (abbreviated as TG in  FIG. 22  and elsewhere) generator  151  and the above-mentioned communication port  147  connected to the timing generator  151 .  
         [0236]     A CPU  152  conducting control operation and a memory  153  such as a flash memory having written therein a program determining the control operation of the CPU  152  are provided inside the timing generator  151 , and the contents of programs thereof can be rewritten by connecting to the rewriting unit  149 . The other capsule body  102 B has the same structure.  
         [0237]     The operation is described below.  
         [0238]     Prior to using the endoscope for endoscopic examination, the cover  146  is removed and the capsule body  102 A′ is set into the rewriting unit  149 , as shown in  FIG. 23 . Then, input keys  150  are manipulated and the rewriting unit  149  sends data such as driving timing of illumination and image pickup or illumination period to the timing generator  151  of capsule body  102 A′ via the communication port  147 .  
         [0239]     The CPU  152  of timing generator  151  rewrites the data in memory  153  with the transmitted data. Thus, the CPU  152  serving as a setting unit can randomly set from the outside the settings required for the realization of functions in at least one of the illumination device, observation device, wireless transmission unit, and control unit.  
         [0240]     The capsule body  102 A′ is thereafter disconnected from the rewriting unit  149 , and the cover  146  is attached. Further, the same operation is conducted with respect to the other capsule body  102 B′. The patient  117  is then asked to swallow the capsule-type endoscope  101 B.  
         [0241]     Illumination and image pickup are then conducted at the illumination and device timing set by manipulating the input keys  150 .  
         [0242]     As a specific example of data that are written, for example, when mainly the large intestine of the patient  117  is examined, the settings are made such that one frame image is picked up in 2 seconds within 6 hours after the capsule-type endoscope  101 B was swallowed and two frame images are picked up in 1 second after the 6 hours have elapsed.  
         [0243]     In such a modification example, a frame rate can be increased to conduct detail observation, for example, in the zone where the patient&#39;s symptoms are suspicious, so as to obtain a large number of images in the zone which requires careful examination based on the patient&#39;s symptoms. In other words, the operator can freely set the image pickup conditions according to the zone which is to be examined, thus, effective picked-up images can be obtained, and the consumption of battery energy can be reduced.  
         [0244]      FIG. 25  shows a capsule body  102 A″ of the second modification example. In the structure of this capsule body  102 A″, a drive and processing circuit  111   a  shown in  FIG. 24  is connected to a memory  154   a  and the memory  154   a  is connected to a communication port  147   a.    
         [0245]     Data on the patient which is to be examined can be input into the memory  154   a  by the rewriting unit  149  prior to endoscopic examination.  
         [0246]     Furthermore, image data picked up by the driving and processing circuit  111   a  are accumulated in the memory  154   a  during endoscopic examination. Once the endoscope capsule has been recovered, the image data accumulated in the memory  154   a  are read out together with the patient&#39;s data by a display system provided with a communication port connectable to the communication port  147   a . As a result, the image data can be managed in a state in which the relationship thereof with the patient&#39;s data is maintained.  
         [0247]     In the first modification example shown in  FIG. 24 , a memory storing the patients data may be also provided, and when the image data are transmitted, the patient&#39;s data stored in the memory may be initially transmitted as header information of the image data.  
       Fifth Embodiment  
       [0248]     The fifth embodiment of the present invention will be described below with reference to FIGS.  26  to  28 .  FIG. 26  shows a capsule-type endoscope  101 C of the fifth embodiment. In the capsule-type endoscope  101 C, for example, the objective lenses  106   a ,  106   b  of capsule bodies  102 A,  102 B of the fourth embodiment are replaced with an objective lens  107   a ′ with a standard angle of view and an objective lens  107   b ′ with a wide angle of view. For sake of simplicity, only the objective lens  107   a ′ and objective lens  107   b ′ are shown in  FIG. 26 . The same is true for  FIG. 27  described hereinbelow.  
         [0249]     In this case, an angle of view providing for an observation field of view from 120° to 140° is set as a standard angle of view, and an angle of view providing for an observation field of view from 160° to 180° is set as the wide angle of view.  
         [0250]     Further, the movement direction in case of endoscopic examination with the capsule-type endoscope  101 C is such that the images are first picked up with the objective lens  107   a ′ with the standard angle of view. Otherwise the structure is identical to that of the fourth embodiment. The observation devices of each hard unit have objective optical systems with mutually different angles of field of view.  
         [0251]     With the present embodiment, overlooking can be reduced by conducting far-point observations with the objective lens  107   a ′ with a standard angle of view in the capsule body  102 A located ahead zone in the movement direction and conducting near-point observations with the objective lens  107   b ′ with a wide angle of view in the rear capsule body  102 B.  
         [0252]      FIG. 27  shows a capsule-type endoscope  101 D of the first modification example. In this capsule-type endoscope  101 D, the devices conducting illumination and image pickup in the direct-viewing direction of capsule bodies  102 A,  102 B in the fourth embodiment are modified so as to conduct illumination and image pickup in the directions inclined to the movement direction of capsule-type endoscope  101 D.  
         [0253]     In case of the structure shown in  FIG. 27 , the fields of view of objective lenses  107   a ″,  107   b ″ are defined by directions inclined in the mutually opposite directions with respect to the movement direction of capsule-type endoscope  101 D. For example, if the field of view of objective lens  107   a ″ is inclined downward, then the field of view of the other objective lens  107   b ″ is inclined upward.  
         [0254]     With the present modification example, since the inclined viewing directions are different ahead and behind the endoscope, the lumens can be observed within a wider range by combining the images obtained with both lenses.  
         [0255]      FIG. 28  shows a capsule-type endoscope  101 E of the second modification example. This capsule-type endoscope  101 E has a structure in which three capsule bodies  156 A,  156 B, and  156 C are linked by a thin flexible strap  57 . Further, the capsule  156 A has an objective lens  158   a  with a field of view in the direct-viewing direction, the capsule body  156 B has an objective lens  158   b  with a field of view in the downward side-viewing direction, and the capsule  156 C has an objective lens  158   c  with a field of view in the upward side-viewing direction.  
         [0256]     With this modification example, the inside of lumens can be observed within even wider range by combining the images obtained with all of the capsule bodies.  
       Sixth Embodiment  
       [0257]     The sixth embodiment of the present invention will be described hereinbelow with reference to  FIG. 29 ,  FIG. 30A , and  FIG. 30B .  FIG. 29  shows a capsule-type endoscope  101 F of the sixth embodiment. In the capsule-type endoscope  101 F, a toggle switch  161  and a charge accumulation circuit  162  are provided as the LED drive circuit  109   a  in the capsule-type endoscopes  102 A′ and  102 B′, for example, in the capsule-type endoscope  101 B shown in  FIG. 22 . Only one capsule body  102 A is shown in  FIG. 29 .  
         [0258]     Further, a transmission-receiving circuit  112   a ′ is employed instead of the transmission circuit  112   a . If a switch operation signal Sk is sent from the outside, it is received by the antenna  113   a , demodulated by the transmission-receiving circuit  112   a ′, and sent to a CPU  152   a  of timing generator  151   a . The CPU  152   a  conducts control operation according to the switch operation signal Sk.  
         [0259]     More specifically, the LED  108   a , as shown in  FIG. 30A  and  FIG. 30B , intermittently emits light under the effect of electric power of battery  114   a . However, if the switch operation signal Sk is received, the CPU  152   a  of timing generator  151   a  switches the toggle switch  161   a  so that it is connected to the charge accumulation circuit  162   a . As a result, the electric power accumulated in the charge accumulation circuit  162   a  is supplied to the LED  108   a  and a large quantity of light is emitted.  
         [0260]     With the present embodiment, for example, when the capsule-type endoscope  101 F reaches the position which apparently requires careful examination, transmitting the switch operation signal Sk from the outside makes it possible to cause the emission of a large quantity of light by the LED  108   a  and to obtain a bright image with a good S/N ratio.  
         [0261]     More specifically, even when the LED  108   a  is caused by the battery  114   a  to emit light inside the esophagus or small intestine, a sufficiently bright image can be obtained. However, inside the stomach or large intestine, the illumination light is not fully received and dark images are sometimes obtained.  
         [0262]     If a switch operation signal Sk is sent from the outside with respect to the zones for which dark images are obtained, for example, zones that are apparently the affected areas, then the entire electric power that was charged into the charge accumulation circuit  162  within the sufficient period of time is supplied via the toggle switch  161  as a large electric current into the LED  108   a , and a large quantity of light is emitted instantaneously. As a result, a bright image, even if still image, with a good S/N ratio can be obtained in the desired zones inside the stomach and large intestines.  
         [0263]     Further, since the LED  108   a  generates heat, illumination in usual observations is conducted at an electric current of no higher than a standard value. However, the LED  108   a  practically does not degrade even if a large electric current such as reaching the standard value is passed instantaneously therethrough.  
         [0264]     In the present embodiment, the amount of illumination light was switched by the switch operation signal Sk. However, a configuration may be also used in which the illumination and image pickup periods can be changed by the switch operation signal, that is, the operation periods of a plurality of illumination devices and observation devices can be changed by the switch operation signal from the outside.  
       Seventh Embodiment  
       [0265]     The seventh embodiment of the present invention will be described below with reference to  FIG. 31  and  FIG. 32 .  FIG. 31  shows a capsule-type endoscope  101 G of the seventh embodiment. In this capsule-type endoscope  101 G, a dip switch  164   a  is provided instead of the communication port  147   a  shown in  FIG. 22  and the transmission frequency of the internal transmission circuit can be variably set by the dip switch  164   a.    
         [0266]     With this embodiment, even if a plurality of capsule-type endoscopes  101 G are swallowed, setting different frequencies for the transmission of image signals by each endoscope makes it possible to recognize and manage the signals during receiving.  
         [0267]      FIG. 32  shows a capsule-type endoscope  101 H of the modification example of the seventh embodiment. In this capsule-type endoscope  101 H, an infrared radiation (IR) port  167   a  is provided on the inner side of a transparent cover glass  166   a  provided on the external surface in the capsule body  102 A, for example, shown in  FIG. 29 .  
         [0268]     The communication is conducted with infrared radiation and the IR port  168  provided in the rewriting unit  149 . Further, in this modification example, the cover  146  is not separated. With this modification example, setting of illumination and image pickup timing can be conducted even without connecting to the rewriting device  149 . Thus, the CPU conducts those settings by using remote communication such as infrared radiation communication and the like. Otherwise, the effect obtained is almost identical to that explained with reference to  FIG. 29 .  
       Eighth Embodiment  
       [0269]     The eighth embodiment of the present invention will be described hereinbelow with reference to FIGS.  33  to  35 .  FIG. 33  shows a structure relating to the antenna of external unit  116 . In this embodiment, a stripe-like antenna row  172  is attached to the front button  171  portion of a shirt  143  of the patient  117 . A plurality of antennas  172   a  constituting the antenna row  172  are connected to the external unit  116  with a connection cable  142 .  
         [0270]     The operation and effect of this embodiment are almost identical to those explained with reference to  FIG. 21 .  
         [0271]      FIG. 34  shows the first modification example of the eighth embodiment. In  FIG. 34 , a shirt  174  incorporates the antenna row. Buttons  175  also function as antennas.  
         [0272]      FIG. 35  shows the second modification example of the eighth embodiment. In  FIG. 35 , an apron-like antenna row  176  is in the form of an apron put on the shirt  143 . A plurality of antennas  176   a  are provided in the apron-like antenna row  176 . The operation and effect of this embodiment are almost identical to those explained with reference to  FIG. 33 .  
       Ninth Embodiment  
       [0273]     The ninth embodiment of the present invention will be described hereinbelow with reference to  FIGS. 36A and 36B .  FIGS. 36A and 36B  illustrate a state of endoscopic examination of the ninth embodiment.  FIG. 36A  relates to the initial stage of examination.  FIG. 36B  illustrates how the images obtained in the course of the examination are transmitted from the patient&#39;s home to the hospital.  
         [0274]     In this embodiment, the data capture unit  119 , for example, installed in the external unit  116  is connected to a connection unit  183  of a telephone line  182  connected to a telephone  181 , and further connected to the display system  118  disposed in a hospital  184  via the telephone line  182 .  
         [0275]     Otherwise, the configuration is identical to that of the fourth embodiment.  
         [0276]     As for the operation of this embodiment, when endoscopic examination is conducted, as shown in  FIG. 36A , the patient  117  swallows the capsule-type endoscope  101 .  
         [0277]     Image data obtained with capsule-type endoscope  101  are accumulated in the external unit  116 . Upon completion of the endoscopic examination, the external unit  116  is connected to the data capture unit  119  connected to the telephone line  182  and the image data are automatically transferred to the hospital or other remote site via the telephone line  182 .  
         [0278]     In the hospital, the image data are received and automatically imported. The final diagnostics is conducted by the doctor.  
         [0279]     In this embodiment, diagnostics is possible even when the patient is in a remote location far from a hospital. Furthermore, since the examination of the patient can be conducted not only in a hospital, the degree of freedom of patient  117  is increased.  
         [0280]     Further, the transmission of image data is not limited to that via the telephone line and wireless transmission may be also conducted. Moreover, the transmission may be conducted with other communications means such as cellular phones, internet, and the like.  
       Tenth Embodiment  
       [0281]     The tenth embodiment of the present invention will be described hereinbelow with reference to FIGS.  37  to  42 . In this embodiment, illumination and image-pickup functions are separated between a plurality of capsule bodies, and illumination and image pickup are conducted by combining the operations of the capsule bodies. In a capsule-type endoscope  185  of the tenth embodiment shown in  FIG. 37 , a capsule body  186 A and capsule body  186 B are connected with a strap  187 .  
         [0282]     Further, a LED  188  emitting white light, a LED drive circuit  189 , and a battery  190  are enclosed in the capsule body  186 A. An objective lens  191 , a CMOS image pickup device  192 , a drive and processing circuit  193 , a transmission circuit  194 , and an antenna (not shown in the figure) are enclosed in the other capsule body  186 B. The capsule bodies  186 A,  186 B are connected with a signal line  195 .  
         [0283]     Magnets  196   a ,  196   b  are provided inside the capsule bodies  186 A,  186 B, respectively. As shown in  FIG. 38 , the capsule bodies can be easily attracted to each other by magnetic forces of magnets  196   a ,  196   b  serving as joining components. Therefore, the two capsules are joined in the prescribed position.  
         [0284]      FIG. 38  illustrates the operation of the present embodiment. When endoscopic examination of the patient  117  is conducted, the patient is asked to swallow the capsule-type endoscope  185  straightened out into a line.  
         [0285]     When the endoscope passes through a narrow lumen portion of an esophagus  197 , the endoscope advances to a deeper region, while maintaining the linear shape. If it then reaches a wide zone, such as a stomach  198 , the two capsule bodies  186 R,  186 B are drawn close to each other by the magnetic forces of the magnets  196   a ,  196   b.    
         [0286]     Illumination and image pickup (including the function of transmitting the image signals) are then conducted in such a state. At least one of the capsule bodies is provided with a magnetic sensor, such as a Hall element, for detecting the state in which the capsule bodies are combined by magnetic forces of the magnets  196   a ,  196   b , and the control initiating the illumination and image pickup based on the detection output of the sensor is conducted by a control unit (not shown in the figures). Alternatively, as shown in  FIG. 24 , illumination and image pickup may be conducted after the prescribed time has elapsed, or as shown in  FIG. 29 , the operation control may be conducted based on the external signals.  
         [0287]     With the present embodiment, image signals can be can be obtained by improving the illumination and image pickup functions executed by the capsule bodies. For example, high-resolution images with good S/N ratio can be obtained by increasing the quantity of illumination light or increasing the number of pixels in the image pickup element.  
         [0288]      FIGS. 39A and 39B  show a capsule-type endoscope  185 ′ of the first modification example. The magnets  196   a ,  196   b  are not used in the capsule-type endoscope  185 ′ and a strap  187 ′ formed from a shape memory material is employed as the strap  187  serving as a joining member.  
         [0289]     In this case, the strap  187 ′ formed from a shape memory material was subjected to shape memory processing such that it has a linear shape at room temperature, as shown in  FIG. 39A , but is bent, as shown in  FIG. 39B , if the temperature becomes no less than the body temperature, thereby combining the two capsule bodies  186 A,  186 B. In this case, too, the operation and effect are almost identical to those explained with reference to  FIG. 37 .  
         [0290]      FIGS. 40A and 40B  show a capsule-type endoscope  185 ″ of the second modification example. In the capsule-type endoscope  185 ″, a strap  187 ″ is formed from a spring material processed (impelled) so as to be bent and to combine the two capsule bodies  186 A,  186 B, as shown in  FIG. 40A . When the endoscope is swallowed, the strap is straightened out, as shown in  FIG. 40B . In this case, too, the operation and effect are almost identical to those explained with reference to  FIG. 37 .  
         [0291]      FIG. 41  shows a capsule-type endoscope  201  of the third modification example. In this modification example, combining the capsules improves the illumination and image pickup function, more specifically, the image pickup range, over those obtained when the capsules are not combined.  
         [0292]     In the capsule-type endoscope  201 , three capsule bodies  202 A,  202 B,  202 C are linked with a thin soft strap  203 . The capsule body  202 A and other capsule bodies are hard and have a hard length shown in the figure.  
         [0293]     The objective lenses  204   a ,  204   c  with a field of image view inclined upward are enclosed in transparent covers in the respective capsule bodies  202 A,  202 C on both end sides, and image pickup elements  205   a ,  205   c  are disposed in image forming positions of respective lenses. The image pickup elements  205   a ,  205   c  are driven and signals therefrom are processed by the image element drive and processing circuits  206   a ,  206   c.    
         [0294]     Further, LEDs  207   a ,  207   c  for illumination are disposed around the objective lenses  204   a ,  204   c , respectively. The LEDs  207   a ,  207   c  are driven by an LED drive circuit  208  provided in the central capsule body  202 B.  
         [0295]     Further, signals that were processed by the image element drive and the processing circuits  206   a ,  206   c  are sent to a transmission circuit  209  provided in the central capsule body  202 B and are transmitted to the outside from an antenna (not shown in the figure). A battery  210  is also enclosed in the capsule body  202 B. Energy such as electric current is supplied to the observation devices such as the image pickup elements  205   a ,  205   c  enclosed in the capsule bodies  202 A and  202 C by the battery  210 .  
         [0296]     Magnets  211   a ,  211   c  are provided inside the capsule bodies  202 A,  202 C on both end sides.  
         [0297]     Therefore, similarly to the case explained with reference to  FIG. 38 , if the capsule-type endoscope  201  reaches a wide portion such as a stomach, the capsule bodies  202 A,  202 C located on both end sides are attracted and combined by the magnets  211   a ,  211   c , as shown in  FIG. 42 . Therefore, the two capsules are joined in the prescribed position.  
         [0298]     In such a state, image pickup is possible within a wide range because of respective inclined fields of view. The operation and effect in this case are similar to those explained with reference to  FIG. 37 .  
         [0299]     The present invention also covers embodiments composed, for example, by partial combinations of the above-described embodiments.  
         [0300]     Having described the preferred embodiments of the invention referring to the accompanying drawings, it should be understood that the present invention is not limited to those precise embodiments and various changes and modifications thereof could be made by one skilled in the art without departing from the spirit or scope of the invention as defined in the appended claims.