Recently, a capsule endoscope including an imaging function and a radio communication function has been proposed in the filed of an endoscope. The capsule endoscope is configured to be swallowed by an examinee as a subject for an observation (examination) to travel inside organs (inside of a body cavity) such as a stomach or a small intestine by a peristaltic movement to capture images one by one by using the imaging function, during an observation period until the capsule endoscope is naturally excreted from a body of the examinee (human body).
During the observation period in which the capsule endoscope travels inside the organs, image data captured inside the body cavity by the capsule endoscope is sequentially transmitted to an external device provided outside the subject, through the radio function such as a radio communication, and stored in a memory provided in the external device. By carrying the external device including the radio function and a memory function, the examinee can move without inconvenience during the observation period from when the examinee swallows the capsule endoscope until the capsule endoscope is excreted. After the observation is finished, a doctor or a nurse can make a diagnosis by displaying body cavity images on a display unit such as a display, based on the image data stored in the memory of the external device.
The above type of the capsule endoscope includes such a swallowable type as disclosed in Patent Document 1, and such a configuration has been proposed that the capsule endoscope internally includes a reed switch that switches ON/OFF by an external magnetic field for controlling a drive of the capsule endoscope, and is accommodated in a package that includes a permanent magnet for providing the external magnetic field. In other words, the reed switch provided in the capsule endoscope has a configuration to keep an OFF state under such a circumstance that a magnetic field having larger strength than a predetermined strength is provided, and to switch to an ON state as the strength of the external magnetic field decreases. Accordingly, when accommodated in the package, the capsule endoscope is not activated. By removing the capsule endoscope from the package when the capsule endoscope is swallowed, the capsule endoscope is moved away from the permanent magnet to be unaffected from the magnetic strength, and starts to drive. With the above configuration, when accommodated in the package, the capsule endoscope is not to be activated, and after being removed from the package, the capsule endoscope captures an image by an illuminating function and the imaging function and transmits an image signal by the radio function.    Patent Document 1: International application No. 01/35813 pamphlet    Patent Document 2: Japanese Patent Application Laid-Open No. 2002-345743
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