JP2006187456A - Capsule endoscope - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a capsule endoscope capable of turning on a power supply switch by an operation outside a capsule liquidtightly covering a circuit without using a force such as a magnetic force affecting the circuit other than the power supply switch. <P>SOLUTION: The capsule 10 of this capsule endoscope 1 is interposed with a power switch circuit 24 between a battery 220 and a circuit system 26 on the way to a power current supply wire. The power switch circuit 24 is constituted of a photodiode 242 passing a current by receiving a light and a thyristor 21 allowing the passing of the power current on the power current supply wire using the current passed by the photodiode 242 as a trigger. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a capsule endoscope that wirelessly transmits an image signal obtained by photographing an inside of a body cavity of a subject to the outside of the subject.

  As is well known, there is an electronic endoscope system as a system for observing the digestive tract of a subject orally. This electronic endoscope system includes an electronic endoscope having a flexible tubular insertion portion in which an imaging device for imaging a subject is incorporated at the tip thereof, and an image signal output from the electronic endoscope. A processor device for performing processing and a monitor for displaying an image based on an image signal processed by the processor device are provided. When actually observing the digestive tract of a subject using such an electronic endoscope system, the insertion portion of the electronic endoscope is orally introduced into the body cavity (digestive tract) of the subject. It must be, but for the subject, the state where the tube constituting the insertion portion was inserted into the throat was very painful and unbearable.

  Therefore, in recent years, in order to eliminate the pain of the subject caused by inserting the insertion portion of the electronic endoscope into the throat, the subject swallows the body cavity of the subject (in the digestive tract). 2. Description of the Related Art A capsule endoscope system has been developed that includes a capsule endoscope that is introduced to a patient, and a processor device and a monitor that are arranged outside the body of a subject.

  This capsule endoscope is composed of a combination of an objective optical system and an image sensor, and also includes an imaging device that generates an image signal by imaging the body cavity of a subject, and a plurality of LEDs and is imaged by the imaging device. An illuminating device that irradiates illumination light to a range, a transmitting device that receives a control signal for the imaging device and transmits an image signal obtained by imaging the subject on a carrier wave, and these A control circuit that controls the device and a circuit that is included in the device and a battery that supplies a drive current to the control circuit are liquid-tightly covered with a capsule.

  Further, the processor device in this capsule endoscope system transmits a control signal to the capsule endoscope on an carrier wave that passes through the body of the subject, and an image signal transmitted from the capsule endoscope. Receive. Then, the processor device performs various processes on the received image signal to display an image in the body cavity on the monitor.

According to such a capsule endoscope system, since the subject can take an image of the inside of the body cavity simply by swallowing a small capsule endoscope, the inside of the body cavity of the subject (without the subject's pain) The inner wall of the digestive tract can be observed. (For example, see Patent Document 1)
Japanese Patent Laid-Open No. 2003-210395

  In a capsule endoscope used in such a capsule endoscope system, the capsule must be liquid-tightly sealed in order to protect various devices and circuits incorporated therein from the environment inside the body cavity. On the other hand, since the capacity of the battery built into the capsule is limited, a switch for cutting off the power supply current is interposed in the middle of the power supply current supply line between the battery and each circuit component, so that the subject's It is necessary to supply a drive current to each circuit component by opening this switch until immediately before introduction into the body cavity and closing this switch immediately before introduction. In order to satisfy both of these two requirements, there is an example in which a power switch interlocked with a push button that penetrates the capsule through an O-ring is provided. It is desirable to close the switch provided in the capsule by eliminating the energy and applying energy from the outside of the capsule. In addition, the configuration in which the switch is interlocked with the push button is not preferable because a malfunction may occur due to a mechanical influence such as an impact applied when the capsule endoscope is dropped. Therefore, the capsule endoscope described in Patent Document 1 adopts a configuration in which the switch is closed by applying a magnetic force from the outside of the capsule.

  However, when the magnetic force is applied to the capsule endoscope in this way, the magnetic force has an effect of changing the movement of electrons, so that it is necessary to shield the circuits other than the switch. As a result, the manufacturing process of the capsule endoscope becomes more complicated, resulting in a problem that the manufacturing cost increases.

  The present invention has been made in view of the above-described problems, and the problem is that a power source is operated by an operation from the outside of a capsule that liquid-tightly covers the circuit without using a force that affects the circuit other than the power switch. To provide a capsule endoscope that can be switched on.

  The capsule endoscope of the present invention devised to solve the above problems obtains an image signal by imaging the body cavity when it is introduced into the body cavity of a subject, and wirelessly transmits the image signal to the outside. A capsule endoscope having a built-in circuit that intervenes in the middle of a power source and a power source current supply line provided between the power source and a circuit component constituting the circuit, and until the light is received, the power source current A power switch circuit that electrically opens the supply line and electrically closes the power supply current supply line after receiving light, and the circuit, the power supply, and the power switch circuit are liquid-tightly covered and the electric switch And a capsule that transmits light received by the circuit.

  If comprised in this way, the power switch circuit which interrupts a drive current in the middle of the power supply current supply line between a power supply and a circuit component can be operated from the outside of a capsule through the light which permeate | transmits a capsule. Therefore, since the capsule only needs to pass the light received by the power switch circuit, it does not require any moving parts and is highly liquid-tight. Further, unlike magnetic force, light does not affect any circuit other than the power switch circuit, so that no special light shielding means is required in addition to the normal light shielding means required by the imaging apparatus. Therefore, the manufacturing process of the capsule endoscope is not complicated, and the manufacturing cost is not increased.

  In the capsule endoscope according to the present invention, since the power switch circuit is operated through the light passing through the capsule, the internal circuit is kept liquid-tight by the capsule and the circuits other than the power switch circuit are affected by this. Nothing.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  The capsule endoscope 1 according to the present embodiment is orally introduced into a body cavity of a subject and images the inside of the body cavity, and sets an image signal obtained by imaging the inside of the body cavity outside the body of the subject. Wirelessly transmitted to the processor unit.

  FIG. 1 is a sectional view showing a longitudinal section along the central axis in order to represent the internal configuration of the capsule endoscope 1. In order to simplify the following description, the left side of FIG. 1 is defined as “front side” and the right side of FIG. 1 is defined as “rear side”.

  As shown in FIG. 1, the capsule endoscope 1 includes a cylindrical frame 20 that houses circuit components, an imaging unit (observation means) 21 that is housed in the frame 20, a battery case 22, and the like. A transmission circuit (communication means) 23 mounted on the rear end face of the battery case 22, a power switch circuit (starting means) 24, and a photodiode 242 constituting the power switch circuit 24 (see FIGS. 2 to 4). The optical filter 25 that covers the light receiving surface of the optical fiber and the capsule 10 for storing and protecting these components therein.

  The capsule 10 includes a cylindrical barrel portion 101 whose rear end portion is semispherical and a hemispherical transparent cover 102 that is liquid-tightly attached to the front end of the barrel portion 101. The body 101 is made of an opaque resin having acid resistance, and a circular through hole 101a is formed in the center of the rear end thereof, and the periphery of the through hole 101a is cut into a flat shape. A lid (starting light incident window) 103 made of a transparent resin having acid resistance is fitted in the through hole 101a in a liquid-tight manner. The outer surface of the activation light incident window 103 is continuous with the outer surface of the body 101 to form a hemispherical surface. Therefore, the capsule 10 has a so-called capsule shape as a whole. The transparent cover 102 is also made of an acid-resistant transparent resin, and has a role as a dome port that keeps the distance from the objective optical system 212 of the imaging unit 21 to the subject moderate.

  The frame 20 is a cylindrical circuit board, and holds the imaging unit 21 and the battery case 22 inside thereof. Further, a circuit pattern for electrically connecting the imaging unit 21, the transmission circuit 23, and the power switch circuit 24 to transmit various signals and power current is printed on the inner peripheral surface of the frame 20. .

  The imaging unit 21 is a unit that captures an image in a body cavity, and includes a light emitting diode 211, an objective optical system 212, a lens barrel 202, an image sensor 213, various circuit components 214, and an imaging substrate 215.

  The lens barrel 202 is a frame for holding the objective optical system 212 and the light emitting diode 211 in the frame 20, and has a cylindrical shape whose radius is slightly smaller than that of the frame 20. The lens barrel 202 is fixed in the frame 20 so that the front end surface thereof is slightly recessed from the front edge of the frame 20. The lens barrel 202 has an objective lens holding hole 202a extending therethrough along the central axis thereof, and light emitting diode fixing holes 202b are formed in two point-symmetric positions with the objective lens holding hole 202a interposed therebetween. I'm leaning. A plurality of lenses constituting the objective optical system 212 are fitted into the objective lens holding hole 202a on the lens barrel 202, and a light emitting diode 211 is fitted into each light emitting diode fixing hole 202b.

  As each light emitting diode 211, a high-luminance type light emitting diode that emits white light is used. Each light emitting diode 211 emits light when a driving current is supplied from the battery 220 in the battery case 22 through the power switch circuit 24, the circuit pattern on the inner peripheral surface of the frame, and the imaging substrate 215, and the capsule endoscope When 1 is introduced into the body cavity, the inside of the body cavity is illuminated.

  The objective optical system 212 is an optical system for connecting an image in the body cavity, and is fixed in the objective lens holding hole 202a of the lens barrel 202 so that its optical axis is coaxial with the central axis of the transparent cover 102. Has been.

  The image sensor 213 is an image sensor such as a CCD that photoelectrically converts an image formed on the imaging surface by the objective optical system 212, and converts an image in the body cavity into an electrical signal. The image sensor 213 is arranged so that the imaging surface comes to a position where the objective optical system 212 connects the images in the body cavity. Note that the objective optical system 212 and the image sensor 213 correspond to an imaging device.

  The imaging substrate 215 is a printed circuit board that electrically connects and mechanically holds these circuit components by mounting the image sensor 213 and various circuit components 214. The imaging substrate 215 has a flat cylindrical shape slightly smaller in diameter than the frame 20 and is coaxially bonded to the rear end surface of the lens barrel 202. Therefore, in a state where the imaging unit 21 is held inside the frame 20, the outer peripheral surface of the imaging substrate 215 is in contact with the inner peripheral surface of the frame 20. An image sensor 213 is mounted at the center of the surface of the imaging substrate 215 bonded to the lens barrel 202, and various circuit components 214 are mounted at the center of the surface facing this surface. The circuit pattern formed on the imaging substrate 215 is connected to two sets of leads 216 penetrating through the lens barrel 202 up to the respective light emitting diode fixing holes 202b. The light emitting diode 211 is electrically connected to the imaging substrate 215 through the lead 216, and receives a drive current supplied through the circuit pattern on the imaging substrate 215 and the lead 216. Further, an anode contact portion 221 that is an electrode that comes into contact with the anode of the battery 220 described later is mounted on the rear end surface on the back side of the surface on which the image processing circuit 214 is mounted on the imaging substrate 215.

  The battery case 22 is an insulator having a bottomed cylindrical shape whose diameter is slightly smaller than that of the frame 20. The battery case 22 accommodates a battery 220 (corresponding to power supply means) in a space inside thereof, and is inserted into the frame 20 with an opening end thereof facing the imaging substrate 215. In this state, the outer peripheral surface of the battery case 22 is in contact with the inner peripheral surface of the frame 20. A cathode contact portion 222 that is a spring-like electrode that contacts the cathode of the battery 220 is mounted on the bottom surface inside the battery case 22. A transmission circuit 23 and a power switch circuit 24 are mounted on the rear end surface of the battery case 22. The cathode contact portion 222 is electrically connected to the ground electrode of each circuit component via the power switch circuit 24. For example, imaging is performed through the circuit pattern formed on the battery case 22 to the ground electrode of the transmission circuit 23 through the circuit pattern on the battery case 22, the circuit pattern on the frame 20, and the circuit pattern formed on the imaging substrate 215. The circuit board 214 is electrically connected to various circuit components 214, the image sensor 213, and the ground electrodes of the light emitting diodes 211, respectively. The power supply electrodes of these circuit components are in contact with each other through the circuit patterns, and the circuit patterns on the imaging substrate 215 (and the circuit patterns on the frame 20 and the battery case 22). The part 221 is electrically connected.

  The transmission circuit 23 is a circuit component that transmits the image signal input from the image sensor 213 on a carrier wave in a frequency band assigned in advance (modulation), performs amplification, and the like, and then wirelessly transmits from the antenna.

  The power switch circuit 24 is an optical switch having the configuration shown in the circuit diagram of FIG. FIG. 2 is a schematic circuit diagram showing wiring of a power supply line for supplying a power supply current to each circuit component in the capsule endoscope 1, and the various circuit components 214, the image sensor 213, and the light emitting diodes 211 described above. The transmission circuit 23 is generally referred to as a “circuit system 26”. As shown in FIG. 2, the power switch circuit 24 includes a thyristor 241 and a light source conversion circuit 240 that activates the thyristor 241. As shown in FIG. 3, the cathode is connected to the cathode of the battery (power source) 220 through the cathode contact portion 222 and the anode is connected to the ground electrode of the circuit system 26 as shown in FIG. A thyristor (SCR) 241, and a bias power supply 243 and a photodiode 242 connected in series in the forward direction between the cathode and the gate of the thyristor 241. Therefore, when the photodiode 242 is not receiving light, the photodiode 242 cuts off the gate trigger current to be applied to the gate of the bias power supply 243 thyristor 241, so that the cathode-anode of the thyristor 241 is also disconnected. As a result, no drive current is supplied to the circuit system 26. On the other hand, when the photodiode 242 receives light of a predetermined value or more, the gate trigger current from the bias power supply 243 is applied to the gate of the thyristor 241, so that a current can flow between the cathode and the anode of the thyristor 241. As a result, the drive current from the battery 220 is supplied to the circuit system 26. Note that the optical filter 25 is a filter that transmits only light having a specific wavelength (starting light) and causes the photodiode 242 to receive the light. For example, the optical filter 25 transmits light having a wavelength band of 700 to 1500 nm.

  In order to assemble such a capsule endoscope 1, an assembly operator assembles the imaging unit 21 in advance and mounts the transmitter 23 and the power switch circuit 24 on the battery case 22. Then, the assembling worker inserts the imaging unit 21 and the battery case 22 containing the battery 22 into the frame 20 to make the respective circuit patterns conductive. Further, the assembling worker stores the frame 20 in the body 101 to which the activation light incident window 103 is fixed. In this state, the assembly operation of the capsule endoscope 1 is completed by fixing the edge of the transparent cover 102 to the front edge of the body 101 in a liquid-tight manner. Since this operation is performed in an environment where there is no startup light, the power switch circuit 24 is not turned on unintentionally. Moreover, since the completed capsule endoscope 1 is immediately enclosed in the light shielding bag, the power switch circuit 24 will not be turned on thereafter. The capsule endoscope 1 is shipped from the factory in this state.

  When the operator intends to examine the body cavity (in the digestive tract) of the subject using the capsule endoscope 1, the operator removes the capsule endoscope 1 from the light shielding bag, and uses the activation light incident window 103. The startup light is incident. Then, as described above, the power switch circuit 24 is turned on (a state in which a current can flow between the anode and the cathode of the thyristor 241), so that the image processing circuit 214, the image sensor 213, each light emitting diode 211, and the transmission circuit 23 are turned on. On the other hand, the power supply current from the battery 220 is supplied. As a result, when these circuit components perform a predetermined function, an image signal indicating an image in the body cavity is wirelessly transmitted to a processor device (not shown). Once the power switch circuit 24 is turned on (a state in which a current can flow between the anode and cathode of the thyristor 241), the power switch circuit 24 is not turned off even if the current supply to the gate portion of the thyristor is interrupted. Therefore, even if the surgeon introduces the capsule endoscope 1 into the body cavity of the subject and no activation light enters the activation light incident window 103, the power switch circuit 24 causes a drive current to flow. to continue.

  According to the capsule endoscope 1 of the present embodiment configured as described above, the activation light incident on the inside of the capsule 10 from the outside of the capsule 10 through the activation light incident window 103 in order to operate the power switch circuit 24. Since it is used, it is not necessary to provide any movable part in the capsule 10, and the capsule 10 itself can be kept liquid-tight. In addition, unlike the case where magnetism or the like is used, the starting light does not affect the electric circuits other than the power switch circuit 24 at all.

Embodiment 2

  In the second embodiment of the present invention, the thyristor (SCR) 241 in the power switch circuit 24 is replaced with a triac 244 as shown in the schematic circuit diagram of FIG. 4 in comparison with FIG. 2 in the first embodiment described above. Is. A thyristor 241 and a light source conversion circuit 240 for starting the thyristor 241 are included. A more specific circuit configuration is as shown in the detailed circuit diagram of FIG. This triac 244 performs the same operation as the triac (SCR) 241 in FIG. 3 as long as the way of connecting the bias power supply 243 and the photodiode 242 is the same as that in FIG. Therefore, the power switch circuit 24 in the second embodiment also performs exactly the same operation as the power switch circuit 24 in the first embodiment described above. Other configurations and operations in the second embodiment are exactly the same as those in the first embodiment described above, and a description thereof will be omitted.

Embodiment 3

  The third embodiment of the present invention has the circuit configuration shown in the schematic circuit diagram of FIG. 4 as in the second embodiment described above. The detailed circuit diagram of FIG. As shown in FIG. 5, compared with FIG. 5, the bias power supply 243 and the photodiode 242 are connected so that the polarities are opposite to each other, whereby the direction of the gate trigger current with respect to the triac 244 is reversed. Yes. Even if the direction of the gate trigger current is reversed in this way due to the characteristics of the triac 244, the triac 244 operates in exactly the same manner as in the second embodiment. Other configurations and operations in the third embodiment are exactly the same as those in the first embodiment described above, and thus description thereof is omitted.

The longitudinal cross-sectional view of the capsule endoscope which is the 1st Embodiment of this invention Schematic circuit diagram showing circuit configuration for supplying drive current via power switch circuit Detailed circuit diagram of circuit configuration Schematic circuit diagram showing a circuit configuration in the second embodiment of the present invention Detailed circuit diagram of circuit configuration The detailed circuit diagram which shows the circuit structure in the 3rd Embodiment of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Capsule endoscope 10 Capsule 22 Battery 23 Transmission circuit 24 Power switch circuit 26 Circuit system 103 Starting light incident window 211 Light emitting diode 213 Image sensor 214 Image processing circuit

Claims (4)

A capsule endoscope having a built-in circuit that obtains an image signal by imaging the inside of the body cavity when it is introduced into the body cavity of the subject and wirelessly transmits it to the outside,
Power supply,
Intervene in the middle of the power supply current supply line provided between the power supply and the circuit components constituting the circuit, and after the light is received, the power supply current supply line is electrically opened until light is received. Is a power switch circuit for electrically closing the power supply current supply line;
A capsule endoscope comprising: a capsule that liquid-tightly covers the circuit, the power source, and the power switch circuit, and that transmits light received by the electrical switch circuit. The power switch circuit is
A thyristor interposed in the middle of the power supply current supply line;
The capsule endoscope according to claim 1, further comprising: a light receiving element that is connected to the gate of the thyristor and applies a gate trigger current to the thyristor only when light is received. The capsule endoscope according to claim 2, wherein an optical filter that transmits only light in a specific wavelength band is provided on an optical path of light incident on the light receiving element. The capsule endoscope according to claim 2, wherein the thyristor is a triac.