JP2003265626A - In vivo implantation apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To raise transmission efficiency in charging and to suppress the rise of temperature at a case surface in a charging-type intravital implantation apparatus which supplies electric energy by electromagnetic coupling with outside of the body. <P>SOLUTION: This apparatus is provided with a charging control circuit 301 for charging power transmitted from outside or power generated by a thermoelectric device 101 to a secondary battery 105 by arranging the thermoelectric device 101 having Seebeck effect and Peltier effect so that respective contacts may come into contact with an inner surface and inner parts on the receiving side of electromagnetic waves in a metallic case 104 directly or via a heat transmitter 103. Further, the apparatus is provided with a circuit 303 for making current flow through the thermoelectric device 101 when a difference between temperatures at the inner surface of the receiving side of electromagnetic waves and that at an inner site except for this in the metallic case 104 becomes larger than a prescribed value. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rechargeable in-vivo implanting device for supplying electric energy from outside the body by electromagnetic coupling, and more specifically, it is mounted on a cardiac pacemaker, an implantable defibrillator or the like. Charging device.

[0002]

2. Description of the Related Art Implantable cardiac pacemakers (hereinafter referred to as pacemakers) and implantable defibrillators (hereinafter referred to as ICDs) are widely used as arrhythmia treatment devices for bradycardia and tachycardia. Currently, a primary battery is used as a power source for these devices, and the battery is generally exhausted in about 6 to 7 years. Therefore, it is necessary to periodically replant the device. Therefore, many patients who have implanted these devices feel anxiety about replanting surgery. Therefore, there is a demand for a longer-life pacemaker and ICD that can be replanted less frequently.

As a means for satisfying such requirements, a pacemaker equipped with a secondary battery has been proposed (for example, Japanese Patent Laid-Open No. 5-317433, "Pacemaker", Japanese Patent Laid-Open No. 6-79).
No. 005 "Pacemaker", JP-A No. 7-246243 "Transdermal charging device for living body implanting device"). According to these proposals, the battery life of the pacemaker can be more than doubled by charging the battery once every several months.

In the conventional rechargeable pacemakers proposed in these, electromagnetic waves generated from the coil outside the body are percutaneously received by the coil inside the pacemaker, and the electromotive force obtained by electromagnetic coupling is rectified and smoothed. After that, the secondary battery is charged by controlling the current value to a predetermined value. Therefore, the patient can charge the battery within a few hours only by placing the coil of the charger on the skin surface of the pacemaker implantation site without being restricted in his / her activity.

[0005]

However, in vivo implantable devices such as pacemakers and ICDs, metal implants such as titanium and titanium-based alloys are highly biocompatible so that components such as electronic circuits and batteries are not corroded by body fluids. Since it is hermetically sealed, the electromagnetic waves that are the energy transmitted for charging are sent to the power receiving coil in the device through this metal case in addition to the skin and subcutaneous tissue.

When an electromagnetic wave passes through a metal, an eddy current is generated in the metal, which raises the temperature of the metal. This is because a part of the electromagnetic wave is changed to heat, which causes a decrease in the transmission efficiency during charging. The decrease in transmission efficiency not only leads to the extension of charging time, but also the heat generated by the eddy current may act on the living tissue at the site where the pacemaker is implanted and may cause an adverse effect such as low temperature burn.

The present invention has been made in view of the above-mentioned problems, and in a rechargeable in-vivo implanting device for supplying electric energy from outside the body by electromagnetic coupling, increases the transmission efficiency and makes it possible to transform living tissues. The purpose is to suppress the temperature rise on the surface of the case that would have an adverse effect.

[0008]

In order to solve the above problems, according to the in-vivo implanting device of the present invention, a metal case for sealing the device, a secondary battery arranged in the metal case, and A coil that obtains electric power by energy transmitted from the outside of the device, a thermoelectric element that converts the temperature difference between the energy receiving side of the metal case and other internal parts into electric power, and the electric power obtained by the coil. Hybrid charging can be performed by including charging control means for charging the secondary battery with the electric power generated by the thermoelectric element.

Further, heat is introduced to the high temperature side of the thermoelectric element from the energy receiving side of the metal case via the heat transfer body, and the low temperature side contacts the internal parts of the apparatus directly or via the heat transfer body. It is characterized by that.

Further, the thermoelectric element has a Peltier effect, and when the temperature difference between the energy receiving side of the metal case and the other internal parts exceeds a predetermined value, a current is applied to the electrothermal element. It is characterized in that it is provided with a means for controlling the flow.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a cross-sectional view of a hybrid rechargeable in-vivo implanting device 10 according to an embodiment of the present invention.

In FIG. 1, an in-vivo implanting device 10 includes a metal case 104, such as a titanium-based metal, having high biocompatibility.
It is sealed by. The thermoelectric element 101 is mounted so that one surface of the thermoelectric element 101 serves as a contact point and contacts the surface of the electronic circuit 102 inside the in-vivo implanting device 10.
On the other surface of the thermoelectric element 101, a thin heat transfer body 103 made of metal or the like having a higher thermal conductivity than the metal case 104 is formed.
The heat transfer body 103 is in close contact with the inner surface (the inner surface on the electromagnetic wave receiving side of the metal case) which is the body surface side when the metal case 104 is implanted. A heat insulating member 106 is arranged at the boundary between the heat transfer body 103 and the internal parts such as the secondary battery 105 so that heat from the metal case 104 is not transferred. This makes the metal case 1
It is possible to prevent the heat of 04 from escaping to the other internal component side and efficiently guide it to the contact point of the thermoelectric element 101.

Here, as the thermoelectric element 101, a thermo module can be preferably used. Thermo module
This is a cooling element composed of a pair of N-type and P-type semiconductor elements. When a direct current is applied, one surface absorbs (cools) and the other surface radiates heat (Peltier effect). It is also possible to switch between heat absorption and heat dissipation by reversing the polarity of the power supply. Moreover, it is also possible to generate power by giving a temperature difference (Seebeck effect).

FIG. 2 shows a system block diagram of the in-vivo implanting device 10 of FIG. As shown in FIG. 2, when charging the implanted device, the power transmission coil 20 of the charger is attached to the body surface of the site where the device is implanted.
And apply an electromagnetic wave. The transmitted electromagnetic wave is received by the power receiving coil 107 in the implanting device 10 via the living tissue and the metal case 104, rectified and smoothed by the charging control circuit 301, and then controlled to have a predetermined current value. Then, the secondary battery 105 is charged.

Here, the electromagnetic wave sent from the power transmission coil 20 seals the implanting device 10 in the metal case 1.
When passing through 04, an eddy current is generated in the metal case 104. The eddy current causes the temperature of the metal case 104 on the electromagnetic wave passing side to rise. That is, the thermoelectric element 10
A temperature difference of about 2 to 3 ° C. occurs between the inner surface of the metal case 104 on which the first contact is in contact and the electronic circuit 102. The Seebeck effect based on this temperature difference causes the thermoelectric element 101 to generate an electromotive force. The generated power is boost circuit 3
After being boosted by 02, it enters the charge control circuit 301,
The power received from the charging coil 107 is combined with the power and charged in the secondary battery 105.

The cooling control circuit 303 includes a metal case 104.
In preparation for the case where the temperature rises to the extent that it adversely affects the living body, the electromotive force generated by the thermoelectric element 101 and the temperature around the electromagnetic wave passing portion of the metal case 104 during charging are constantly monitored.

That is, when the temperature of the metal case 104 rises above a predetermined temperature, the cooling control circuit 303 senses it, and the electric power from the thermoelectric element 101 and the charging coil 10 are detected.
At the same time when the synthesis with the electric power received from 7 is stopped, a direct current is passed through the thermoelectric element 101. The direct current flowing at this time has a pole opposite to the electromotive force generated by the thermoelectric element 101. Due to the Peltier effect that accompanies this energization, the thermoelectric element 101 absorbs the heat generated on the metal case 104 and suppresses the temperature rise.

Further, when the temperature of the metal case 104 drops below a predetermined value due to this heat absorption, the cooling control circuit 303 stops the energization for the cooling operation and controls the charging operation by the thermoelectric element 101 to start again. .

As described above, under the control of the cooling control circuit 303, the thermoelectric element 101 absorbs heat generated within the allowable range of the metal case 104 by converting the heat into electricity,
It operates so as to cool itself against heat generation exceeding the allowable range.

The above-described in-vivo implanting device of the present invention can be charged percutaneously, specifically, by a pacemaker, an ICD, an auxiliary artificial heart, an artificial heart, a nerve stimulator, an implantable drug injection pump, or the like. It can be applied to all required devices.

[0021]

According to the present invention, the heat generated by the eddy current generated when the electromagnetic wave generated from the coil outside the body passes through the metal case of the implanting device is converted into the electric energy by the thermoelectric element, and the power receiving coil inside the device is used. Since charging can be performed in addition to the received charging energy, it is possible to increase the transmission efficiency at the time of charging the in-vivo implanting device using the secondary battery. Also, depending on the situation, it is possible to cool the metal case by passing an electric current through the thermoelectric element, so it is possible to suppress the temperature rise on the surface of the case that causes abnormalities in living tissue and safely perform percutaneous charging. Is.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an in-vivo implantation device according to an embodiment.

2 is a system block diagram of the in-vivo implanting device of FIG. 1. FIG.

[Explanation of symbols]

10 In-vivo implantation device 101 thermoelectric element 102 electronic circuit 103 heat transfer body 104 metal case 105 secondary battery 106 heat insulation section 107 Power receiving coil 20 power transmission coil 301 Charge control device 302 Booster circuit 303 Cooling control device

Claims (3)

[Claims] 1. An in-vivo implantable device having a percutaneous charging function, which is a metal case for sealing the device, a secondary battery arranged in the metal case, and energy transmitted from the outside of the device. Generated by the coil, a thermoelectric element that converts the temperature difference between the energy receiving side of the metal case and the other internal parts into electric power, the electric power obtained by the coil and the thermoelectric element generated by the thermoelectric element An in-vivo implanting device comprising a charging control means for charging the secondary battery with electric power. 2. Heat is introduced to the high temperature side of the thermoelectric element from the energy receiving side of the metal case via a heat transfer body, and the low temperature side of the thermoelectric element directly or internally transfers the heat transfer body to the internal parts of the apparatus. The in-vivo implantation device according to claim 1, wherein the in-vivo implantation device is in contact with the in-vivo device. 3. The thermoelectric element has a Peltier effect, and when the temperature difference between the energy receiving side of the metal case and the other internal parts is larger than a predetermined value, a current is applied to the electrothermal element. The in-vivo implantation apparatus according to claim 1, further comprising means for controlling so as to flow.