JP2643327B2 - In-vitro / out-vitro energy transmission device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an in-vitro / ex-vivo energy transmission device that supplies energy to an artificial organ or the like placed in a living body from outside the living body.

[Conventional technology]

Conventionally, as a device for supplying power to an artificial organ placed in a living body, for example, a capacitor incorporated in an artificial heart, a power supply connector connected to a capacitor of the artificial heart is provided on the body surface, and an external power supply is provided for the power supply connector. Some devices are connected and charged.

There is also a system in which a high-frequency radio wave is used to charge the battery wirelessly without providing a power supply connector (US Pat. No. 3,919,722). Here, a coil provided inside the body and a coil provided outside the body are brought close to each other, and energy is transmitted by electromagnetic induction.

However, in the method using the power supply connector, since the power supply section such as the power supply connector is installed on the body surface of the patient, there is a limitation on a fixing place, and a physical burden is imposed on the patient, and hygienic management is performed. There is a drawback that a large burden is imposed on the operation.

In addition, the wireless charging method using high-frequency radio waves has a problem that the high-frequency waves may affect a human body, for example, may cause an electric shock. In addition, when this is taken into consideration, there is a disadvantage that the efficiency of energy transmission to deep inside the body is deteriorated.

To solve these problems, an element that receives ultrasonic energy is incorporated into an artificial organ, and an ultrasonic oscillation element that oscillates ultrasonic waves is installed outside the body. The present applicant has previously filed an application for an artificial organ energy supply device for supplying energy to an artificial organ to be placed (Japanese Patent Application No. 62-44227).

[Problems to be solved by the invention]

In such wireless transmission of transcutaneous energy using ultrasonic waves, the oscillation frequency of the ultrasonic waves radiated from outside the body needs to match the resonance frequency of the ultrasonic element installed inside the body. If they do not match, the efficiency of converting the vibration received by the ultrasonic element in the body into electricity decreases, and it becomes difficult to transmit sufficient energy from outside the body to the body. In addition, the resonance frequency of the ultrasonic elements installed outside and inside the body changes depending on the surrounding temperature, the dielectric constant of the living body, changes over time, etc., and also varies depending on individual transducers.
Even if the frequency is fixed in advance, the transmission efficiency is reduced.

The present invention has been made in view of the above circumstances, and in an apparatus for transmitting energy inside and outside a living body by transmitting and receiving ultrasonic waves between ultrasonic vibrators provided inside and outside the living body, energy is always efficiently transmitted. Its purpose is to transmit.

[Means for solving the problem]

An in-vitro / out-vivo energy transmission device according to the present invention is provided outside a body or in a body cavity, and a first ultrasonic vibrator for transmitting ultrasonic waves, and a second ultrasonic transducer provided inside a body for converting transmitted ultrasonic waves into an electric signal. And a means for controlling the transmission frequency of the first ultrasonic vibrator so that the frequency of the converted electric signal matches the resonance frequency of the second ultrasonic vibrator.

[Action]

The in-vitro / ex-vivo energy transmission device of the present invention detects the frequency of the transmitted ultrasonic wave based on the converted electric signal,
Since the oscillation frequency of the transmitting-side ultrasonic vibrator is controlled accordingly, ultrasonic waves having a frequency equal to the resonance frequency of the receiving-side ultrasonic vibrator can be transmitted, and energy can be transmitted efficiently.

〔Example〕

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of an in-vitro / out-vivo energy transmission device according to the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of the first embodiment. The living body external unit 10 includes an ultrasonic oscillator 12, a drive circuit 14, an ultrasonic oscillator.
16 and a frequency divider (÷ n) 18. The living body internal unit 20 includes an ultrasonic transducer 22, an AC-DC (AC-DC) converter 24,
It comprises a load 26 such as an artificial organ, a frequency control circuit 28, a voltage controlled oscillator (VCO) 30, a drive circuit 32, and an ultrasonic transducer 34.
The living body external unit 10 is brought into contact with the external surface of the living body via an ultrasonic transmission medium such as water. Alternatively, the extracorporeal unit 10 may be provided in a body cavity via a forceps channel of an endoscope.

An example of the frequency control circuit 28 is shown in FIG. The DC voltage v output from the AC-DC converter 24 and applied to the load 26 is supplied to the input terminal of the analog switch 42 and is also supplied to the input terminal of the analog switch 44 via the inverter 42. The output terminals of the analog switches 42 and 44 are connected to the input terminal of VCO6. On the other hand, the DC voltage v is also supplied to the + input terminal of the comparator 46. The DC voltage v is supplied to the negative input terminal of the comparator 46 via a C and R delay circuit 47. Comparator 46
Is supplied to the gate of the analog switch 40 and also to the gate of the analog switch 44 via the inverter 48.

Next, the operation of the first embodiment will be described. Ultrasonic transducer 12
When power is applied from the drive circuit 14, the ultrasonic vibrator 22
Transmit ultrasonic waves toward. Fp ultrasonic transmission frequency
(For example, 500 KHz).

The transmitted ultrasonic waves are received by the ultrasonic transducer 22 and converted into electric signals, and high-frequency power is generated between terminals of the ultrasonic transducer 22. The high-frequency power is converted into DC power by the AC-DC converter 24 and consumed by the load 26. The DC voltage applied to the load 26 is represented by v.

Thereby, the output power of the drive circuit 14 is converted into an ultrasonic wave, transmitted to the living body internal unit 20, converted into power again, and consumed by the load 26.

Such energy transmission by ultrasonic waves is suitable for transcutaneous power transmission to artificial organs and the like. The reason for this is that even if the distance between the ultrasonic transducers 12 and 22 is somewhat large, the acoustic characteristic of the living body is close to that of water, so that energy loss is small. However, this approach also has disadvantages. That is, unless the oscillation frequency fp of the ultrasonic vibrator 12 is set to an appropriate value, the transmission efficiency decreases.

FIG. 3 shows the load on the transmission frequency fp of the ultrasonic transducer 12.
The characteristics of the voltage v applied to 26 are shown. The optimum value fq of the transmission frequency fp indicating the maximum value of the applied voltage v is equal to the resonance frequency of the ultrasonic transducer 22. For this reason, the transmission frequency fp is changed to the resonance frequency fq
A frequency control circuit 28 for matching is provided in the living body internal unit 20.

 Hereinafter, the operation of the frequency control circuit 28 will be described.

The voltage v applied to the load 26 is input to the VCO 30 as a voltage v 'via a frequency control circuit 28. In the frequency control circuit 28, the positive input of the comparator 46 responds to the voltage v in real time, while the negative input responds to the voltage v after some delay by the delay circuit 47. Therefore, the comparator 46
Generates a "0" level output when the voltage v decreases, and a "1" level output when the voltage v increases. Thus, when the voltage v decreases, the analog switch 40 is turned on, and the voltage v
Applied to VCO30. On the other hand, when the voltage v increases, the analog switch 44 is turned on, and the inverted voltage of the voltage v becomes VCO3
Applied to 0.

FIG. 4 shows the characteristic of the frequency fr of the oscillation output with respect to the input voltage v 'of the VCO 30. Therefore, when the transmission frequency fp increases and exceeds the resonance frequency fq, the load voltage v decreases, so that the input voltage v ′ of the VCO 30 increases, and the oscillation frequency fr
Is reduced. Conversely, the transmission frequency fp decreases and the resonance frequency
If fq or less, since the load voltage v increases, VC
The input voltage v 'of O30 decreases and its oscillation frequency fr increases.

The output of the VCO 30 is amplified by the drive circuit 32 and causes the ultrasonic transducer 34 to oscillate. For this reason, the ultrasonic vibrator 34
Oscillates at fr. Here, when fp = fq, the characteristics of the VCO 30 are set so that fr = 5 MHz. The ultrasonic waves from the ultrasonic oscillator 34 are transmitted to the ultrasonic oscillator 16 via the ultrasonic transmission medium.

This ultrasonic wave is received by the ultrasonic transducer 16, and a high-frequency voltage having a frequency fr is generated between its terminals. This high-frequency voltage is frequency-divided by a frequency divider 18 into 1 / n (here, 1/10) and input to the drive circuit 14 to cause the ultrasonic transducer 12 to oscillate.

As described above, according to the first embodiment, the components from the ultrasonic transducer 12 to the drive circuit 14 constitute one negative feedback circuit, and the transmission frequency fr of the ultrasonic transducer 12 is reduced by the resonance of the ultrasonic transducer 22. When the frequency fq deviates, the transmission frequency is automatically controlled to match the optimum value of the transmission efficiency, that is, the resonance frequency fq of the ultrasonic transducer on the receiving side.

FIG. 5 shows a block diagram of the second embodiment. This is one in which the ultrasonic transducers 12, 16; 22, 34 of the first embodiment are each composed of one ultrasonic transducer 50, 54. here,
A diode 56 is connected between the drive circuit 32 and the ultrasonic transducer 54.

The basic operation is the same as in the first embodiment. The oscillation frequency fr of the VCO 30 is superimposed on the transmission frequency fp of the ultrasonic transducer 12, but if fr> fp or fr <fp is set, fr
Is easy to detect.

FIG. 6 is a block diagram of the third embodiment. The living body external unit 10 includes an ultrasonic transducer 50, a drive circuit 14, and a waveform memory 6.
0, consisting of a selector 62. The living body internal unit 20 includes an ultrasonic transducer 54, a switch 64, a rectifier circuit 66, a load 26, and a secondary battery.
Consists of 68.

By instantly turning on / off the switch 64, an impulse voltage is applied to the vibrator 54. When an impulse is applied to the ultrasonic transducer 54, an ultrasonic wave equal to the resonance frequency is generated from the transducer 54. The waveform is received by the ultrasonic transducer 50, stored in the waveform memory 60, and the same waveform is continuously sent to the drive circuit 14. By the above operation, the ultrasonic transducer 50 transmits an ultrasonic wave having a frequency equal to the resonance frequency of the ultrasonic transducer 54.

By generating an impulse periodically as needed by the switch 6 and refreshing the data in the waveform memory 1, energy can always be efficiently transmitted.

The present invention is not limited to the above-described embodiment, but can be variously modified.

〔The invention's effect〕

As described above, according to the internal / external energy transmission device of the present invention, the frequency of the transmitted ultrasonic wave is detected based on the converted electric signal, and the oscillation frequency of the ultrasonic transducer on the transmission side is detected accordingly. Is controlled, ultrasonic waves having a frequency equal to the resonance frequency of the ultrasonic transducer on the receiving side can be transmitted, and energy can be transmitted efficiently.

[Brief description of the drawings]

FIG. 1 is a block diagram of a first embodiment of an in vivo / external energy transmission apparatus according to the present invention, FIG. 2 is a circuit diagram of a frequency control circuit of the first embodiment, and FIG. 3 shows a relationship between a transmission frequency and a load voltage. FIG. 4, FIG. 4 is a diagram showing characteristics of the VCO, FIG. 5 is a block diagram of a second embodiment of the present invention, FIG. 6 is a block diagram of a third embodiment of the present invention, and FIG. FIG. 4 is a signal waveform diagram illustrating an operation of the example. 12,16,22,34 …… Ultrasonic vibrator, 14, 32 …… Drive circuit, 1
8: Divider, 24: AC-DC converter, 26: Load, 2
8 ... frequency control circuit, 30 ... VCO.

Claims (1)

(57) [Claims] A transmitting means provided outside the body or in a body cavity for transmitting ultrasonic waves; a receiving means provided inside the body for converting the ultrasonic waves into an electric signal; and an electric signal generated by the receiving means. And a means for matching the transmission frequency to the resonance frequency of the receiving means in accordance with the following.