A body-insertable apparatus including a capsule-like casing, an illuminating unit, an imaging unit, and an antenna is provided. The capsule-like casing is formed in a capsule-like shape and includes a transparent imaging dome. The illuminating unit is arranged in the capsule-like casing and illuminates an examined site of a subject through the imaging dome. The imaging unit is arranged in the capsule-like casing and takes an image of the examined site illuminated by the illuminating unit. The antenna is arranged in the imaging dome at a position outside an imaging field of view of the imaging dome to transmit image information obtained through imaging by the imaging unit to an outside of the subject.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2006-334823, filed Dec. 12, 2006, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a body-insertable apparatus which is inserted into a subject to take an image of an examined site and to output the image by radio to an outside of the subject.

2. Description of the Related Art

In recent years, a swallowable capsule endoscope has been developed in the field of endoscope. The capsule endoscope is equipped with an imaging function and a radio function as described in Japanese Patent Application Laid-Open No. 2003-19111, for example. After being swallowed from the mouth of a patient for an observation of an interior of a body cavity, the capsule endoscope travels through internal organs such as an esophagus, a stomach, and a small intestine, following peristaltic movements thereof to sequentially perform imaging until naturally excreted from the body of the patient.

While the capsule endoscope travels through the body cavities, image data obtained through imaging by the capsule endoscope inside the body cavities is sequentially transmitted by radio communication to the outside of the patient (in other words, subject) from an antenna such as a coil antenna. The antenna is arranged at the center of a back-end side of the capsule endoscope which is an opposite side from a side where an illuminating unit and an imaging unit are arranged. The transmitted image data is stored in a memory provided inside a receiver outside the subject. A doctor or a nurse can make diagnosis based on an image shown on a display according to the image data stored in the memory.

Conventionally, commonly-used capsule endoscopes of the above-described type are monocular capsule endoscopes. The monocular capsule endoscope takes only the image of an examined site located in front of the capsule endoscope, i.e., in an advancing direction thereof. In recent years, however, a pantoscopic capsule endoscope has been proposed for widening the field of view at the time of observation of, for example, an esophagus. The pantoscopic capsule endoscope takes images of a site behind itself as well as a site in front of itself along the advancing direction. As described in US Patent Application Laid-Open No. 2002-109774, for example, the pantoscopic capsule endoscope is configured to take images behind as well as ahead of a capsule-like casing along the advancing direction thereof in the body cavities, and a set of an illuminating unit such as a light emitting diode (LED) which illuminates an examined site and an imaging unit such as a charge-coupled device (CCD) which takes an image of an examined site is arranged in the capsule-like casing, one set at each of a front-end side and a back-end side.

In the pantoscopic capsule endoscope, one set of the illuminating unit and the imaging unit is arranged at each of the two ends of the capsule-like casing, and therefore, the antenna cannot be arranged at one end side of the capsule-like casing as in the monocular capsule endoscope. Therefore, the antenna must be arranged between or around components housed inside the capsule-like casing (for an example of the monocular capsule endoscope, see Japanese Patent Application Laid-Open No. 2001-112740, for example).

In the capsule-like casing, however, various components are housed, such as a substrate on which a conductive pattern, in particular, a wide ground pattern for grounding is formed, for example, and many electronic components mainly of metal. Therefore, when the antenna is arranged between or around the housed components, transmission waves from the antenna tend to be negatively affected, for example, distorted, shielded, or absorbed, by the conductor or metals. Then, it is difficult to obtain a desirable antenna characteristic, such as a wide directionality. Further, the arrangement of the antenna between or around the housed components necessitates the increased size of the capsule-like casing. Such necessity contradicts a demand for downsizing.

Further, even in the monocular capsule endoscope, the coil antenna, for example, is usually arranged at the center of the back-end side of the capsule-like casing and occupies a large space, and hampers a further downsizing of the capsule-like casing.

SUMMARY OF THE INVENTION

A body-insertable apparatus according to one aspect of the present invention includes a capsule-like casing that is formed in a capsule-like shape and includes a transparent imaging dome, an illuminating unit that is arranged in the capsule-like casing to illuminate an examined site of a subject through the imaging dome, an imaging unit that is arranged in the capsule-like casing to take an image of the examined site illuminated by the illuminating unit, an antenna that is arranged in the imaging dome at a position outside an imaging field of view of the imaging dome to transmit image information obtained through imaging by the imaging unit to an outside of the subject.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

An exemplary embodiment of a capsule endoscope which is a body-insertable apparatus according to the present invention will be described below with reference to the accompanying drawings. It should be noted that the present invention is not limited by the following embodiment. In the drawings, the same or corresponding portion will be denoted by the same reference character.

FIG. 1is a sectional view of an internal structure of a capsule endoscope according to an embodiment.FIG. 2is a schematic perspective view of the capsule endoscope of the embodiment with a part thereof removed. A capsule endoscope1according to the embodiment is an application of a pantoscopic capsule endoscope which is inserted into a subject to take the image of an examined site and output the image by radio to the outside of the subject. The capsule endoscope1is configured with illuminating units11aand11bwhich illuminate examined sites of the subject and imaging units12aand12bwhich take the images of the examined sites. The illuminating unit11aand the imaging unit12a, and the illuminating unit11band the imaging unit12bare respectively included in two imaging blocks13aand13b. The capsule endoscope1further includes a power supply unit14which supplies power to the above-mentioned units. These units are housed inside a capsule-like casing15.

The capsule-like casing15is a capsule-like member including substantially semispherical, transparent imaging domes15aand15band a cylindrical body15c. The imaging dome15acovers one end side of the imaging block13a, whereas the imaging dome15bcovers one end side of the imaging block13b. The body15chas engaging portions16aand16b(grooves, for example) fitting with portions (flanges, for example) of the imaging domes15aand15b, and is engaged with the imaging domes15aand15bin a watertight manner. Inside the body15c, the imaging blocks13aand13bare placed with the power supply unit14arranged therebetween. The capsule-like casing15is formed in such a size that the subject can swallow it from the mouth. The body15cis made of a colored material which does not transmit visible light. The imaging dome of the body-insertable apparatus according to the present invention does not need to be a complete semisphere, and may be an oval or a partially cylindrical shape.

The imaging units12aand12binclude imaging elements18aand18band imaging lenses21aand21b, respectively. The imaging elements18aand18bare CCDs or complementary metal-oxide semiconductors (CMOS), for example, and take the image within a range illuminated by illumination light emitted from the illuminating units11aand11b, respectively. The imaging elements18aand18bare arranged respectively on disk-like imaging substrates17aand17b. The imaging lenses21aand21binclude movable lenses19aand19band fixed lenses20aand20b, respectively, to form an image on the imaging elements18aand18b, respectively. The movable lenses19aand19band the fixed lenses20aand20bare supported by lens holders22aand22b, respectively.

The illuminating units11aand11binclude, for example, light emitting diodes (LED). The illuminating units11aand11bare mounted on the surfaces of disk-like illuminating substrates23aand23b, respectively. The illuminating units11aand11bare arranged at four positions around optical axes of the imaging lenses21aand21b, respectively, above, below, to the right, and to the left of the optical axes. Further, in the imaging blocks13aand13b, signal processing/controlling units24aand24bare mounted on the back surface sides of the imaging substrates17aand17b, respectively, for processing and controlling each unit of the corresponding block. Further, the imaging substrates17aand17bare electrically connected to the illuminating substrates23aand23b, respectively, via a cable as appropriate.

The power supply unit14arranged between the imaging blocks13aand13bis configured, for example, with two button-type batteries25whose diameters are substantially equal to the inner diameter of the body15c. As the battery25, a silver oxide battery, a rechargeable battery, and a power-generating battery can be employed, for example. Further, a power supply substrate26is attached to one of the batteries25. The power supply substrate26is electrically connected to each of the imaging substrate17a, the illuminating substrate23a, and the signal processing/controlling unit24avia a cable or the like as appropriate. Further, the power supply substrate26is electrically connected to each of the imaging substrate17b, the illuminating substrate23b, and the signal processing/controlling unit24bas appropriate via a cable or the like arranged outside the battery25.

Further, the capsule endoscope1according to the embodiment includes antennas27aand27bwhich output image information obtained through imaging by the imaging units12aand12bby radio to a receiver outside the subject. Here, the antennas27aand27bare arranged inside the imaging domes15aand15b, respectively, outside the fields of view of the imaging units12aand12bin the imaging domes15aand15b. The antennas27aand27bare metal coil antennas mounted on the surfaces of the illuminating substrate23aand23b, respectively. The antennas27aand27bare subjected to antireflection treatment. For example, black coating is applied thereto. Modulating circuits are mounted on the back surface sides (inner surface sides) of the illuminating substrates23aand23b, respectively, to perform modulating process so that power supply can be performed near the antennas27aand27b.

After being swallowed by the subject, the capsule endoscope1with the above-described configuration illuminates examined site with the illuminating units11aand11bvia the imaging domes15aand15bwhile imaging the examined sites with the imaging elements18aand18bvia the imaging domes15aand15b. The signal processing/controlling units24aand24bperform necessary signal processing on the image information. The processed image information is output/transmitted to the receiver outside the subject via the corresponding antennas27aand27bby radio. Here, the outputs from the antennas27aand27bare set so that the receiver can distinguish the transmission waves from the antenna27afrom the transmission waves from the antenna27bbased on the difference in transmitting frequencies, or based on the modulation process performed thereon.

In the capsule endoscope1according to the embodiment, the transmitting antennas27aand27bare arranged inside the imaging domes15aand15band outside the imaging fields of view of the imaging domes15aand15b, respectively. Thus, the antennas27aand27bcan be arranged in an unused space in the capsule-like casing15without any disturbance to the imaging operations of the imaging units12aand12b, whereby further space saving and downsizing of the capsule-like casing15can be realized. Further, the antennas27aand27bare arranged outside the imaging fields of view, which form outwardly-expanding opening unobstructed by other units in the imaging domes15aand15b. Therefore, the transmission waves output from the antennas27aand27bare not negatively affected by other housed components such as the illuminating units11aand11b, the illuminating substrates23aand23b, and the imaging substrates17aand17bin the capsule-like casing15, whereby a desirable antenna characteristic, such as a wide directionality, can be secured. Specifically, the directionality is further improved since the antennas27aand27bare provided one for each of the imaging blocks13aand13b.

Further, the antennas27aand27bare mounted on the surfaces of the illuminating substrates23aand23bwhich are electric components arranged at outermost positions in the capsule-like casing15. Therefore, when the antennas27aand27bare arranged outside the imaging field of view of the imaging domes15aand15b, the mountability of the antennas27aand27bis not negatively affected. Further, though the antennas27aand27b, which are made basically of metal and arranged outside the imaging field of view, can negatively affect an imaging system by reflecting the illumination light, the antireflection treatment applied to the antennas27aand27bcan prevent such inconvenience. Further, when the antennas27aand27bare arranged so as to abut on the illuminating units11aand11b, the antennas27aand27bcan be positioned easily without the need of additional means such as adhesive.

FIG. 3is a sectional view of an internal structure of a capsule endoscope according to a first modification. A capsule endoscope1A according to the first modification includes antennas27aand27barranged along internal shapes of the substantially semi-spherical imaging domes15aand15b. More specifically, the antennas27aand27bare configured as metal coil antennas which have smoothly curved shapes conforming to the inner shapes of the imaging domes15aand15b.

Generally in the capsule endoscope, an optical system such as a fish-eye lens is mounted in the imaging units12aand12bto widen the imaging field of view, to 140°, for example, and the space which is outside the imaging field of view tends to decrease. However, when the antennas27aand27bare arranged along the inner shapes of the imaging domes15aand15bas in the first modification, the effective length of the antennas can be made longer within the limited space, which is advantageous for securing a favorable antenna characteristic.

FIG. 4is a sectional view of an inner structure of a capsule endoscope according to a second modification. The second modification takes into consideration a case where the arrangement of the antennas27aand27bshown inFIG. 3cannot cover the sufficient, effective antenna length. In a capsule endoscope1B according to the second modification, extension portions27a′ and27b′ are additionally mounted on the back surface sides of the illuminating substrates23aand23bby necessary lengths as the extensions of the antennas27aand27bas shown inFIG. 4.

FIG. 5is a sectional view of an internal structure of a capsule endoscope according to a third modification. A capsule endoscope1C according to the third modification includes antennas28aand28bformed as planar coil patterns on the surfaces of the illuminating substrates23aand23binstead of the metal coil antennas27aand27b. The antennas28aand28bformed as planar coil patterns do not protrude much in the axial direction of the capsule-like casing15. Therefore, the antennas28aand28bcan easily be arranged outside the imaging field of view even when there is only a small useable space (i.e., unused space) outside the imaging field of view. The planar coil patterns may be formed on the back surface sides of the illuminating substrates23aand23b.

When the antennas28aand28bare formed as planar coil patterns, it is desirable that the antennas28aand28bbe formed similarly to wiring patterns of the illuminating substrates formed through high-precision etching in a fabrication process of the illuminating substrates23aand23b. It is also possible, however, to form planar antennas from the metal coil antennas employed in the capsule endoscopes1A and1B of the first and the second modifications and mount them on the illuminating substrates23aand23b.

FIG. 6is a sectional view of an internal structure of a capsule endoscope according to a fourth modification. In the pantoscopic capsule endoscopes of the embodiment and the modifications described above, one antenna is arranged in each of the imaging blocks13aand13b. In a capsule endoscope1D according to a fourth modification, one antenna27is arranged to be shared by the imaging units12aand12b. The antenna27is arranged, for example, at the side of the imaging dome15a. The single antenna27transmits/outputs the image information obtained through imaging by the imaging units12aand12bto the outside of the subject in a time-divisional manner so that the antenna27can process the outputs of both the imaging units12aand12b.

In the above, the fourth modification is explained as an application of the antenna structure of the capsule endoscope1of the embodiment. However, the antenna structures of the capsule endoscopes1A to1C of the first to the third modifications are similarly applicable.

FIG. 7is a sectional view of an internal structure of a capsule endoscope according to a fifth modification. While the embodiment and the modifications described above relate to the application of a pantoscopic capsule endoscope, a capsule endoscope1E according to the fifth modification is an application of a monocular capsule endoscope. A capsule-like casing15′ is configured as a combination of an imaging dome15aand a bottomed body15d. There is no components corresponding to those arranged at the side of the imaging block13b, and only the components corresponding to those arranged at the side of the imaging block13aare provided.

Similarly to the other capsule endoscopes described above, in the monocular capsule endoscope1E, the antenna27ais arranged in an unused space in the imaging dome15aand outside the imaging field of view of the imaging dome15a, whereby it is not necessary to arrange the antenna at the bottom center of the bottomed body15d. Thus, the capsule-like casing15′ can be further downsized. Further, if the capsule-like casing15′ has a similar size as the conventional casing, the space at the bottom of the bottomed body15dcan be effectively utilized for mounting a signal processor and other functional units, or for mounting the larger battery25to increase a battery capacity. Still further, since the antenna is not arranged in the bottomed body15d, other components can easily be arranged and embedded in the bottomed body15d.

Though the fifth modification is explained as an application of the antenna structure of the capsule endoscope1of the embodiment, the antenna structures of the capsule endoscopes1A to1C of the first to the third modifications are also similarly applicable.