JPH0236269B2 - CHOTANPACHIRYOKI - Google Patents

Description

[Detailed Description of the Invention] The present invention irradiates the human body with ultrahigh-frequency power, for example, to raise the temperature of the human body and promote the activation of fine bubbles. The present invention relates to the ultrashort wave treatment device obtained. Specifically, even if the capacitance and internal resistance change depending on the distance between the conductors applied to the affected part of the human body, the constant ultrahigh-frequency current ensures that the thermal effect does not change at all times.

In this type of ultrashort wave treatment device, the capacitance and internal resistance change depending on the location (thickness, width) of the affected part of the human body.
Since the output current changes accordingly, the impedance is small in thin areas, so a large current flows, resulting in a high temperature rise in the human body and the risk of burns. On the other hand, in a thin affected area, the impedance is high and it is difficult for current to flow, making it impossible to obtain a sufficient thermal effect. Furthermore, as the human body impedance changes, a mismatch with the output transistor occurs, which leads to failure of the ASO standard and destruction of the output transistor. Conventional solutions to the above problems include adjusting the output variable capacitor to adjust the output current, or changing the power supply voltage V _cc to make the thermal effect appropriate. It is supposed to be done. However, it is troublesome to make adjustments each time depending on the affected part of the human body.

The present invention has been made in view of the above points, and focuses on how to hold the conductor and the location (thickness, thickness, etc.) of the affected part of the human body.
The purpose is to maintain a constant ultrahigh-frequency current and to maintain a thermal effect at an appropriate value even if there are changes in capacitance and impedance of internal resistance due to differences in width).
Further, the present invention eliminates the need for manual adjustment of the output current as seen in the conventional example, performs impedance matching, and eliminates destruction of the output transistor.

An embodiment of the present invention will be described below with reference to FIG.

First, an oscillation circuit 1 generates an ultrahigh frequency output, a drive circuit 2 performs power amplification, and this is applied to the gate of a transistor 4. This transistor 4 performs sufficient power amplification, and the inductance of the coil 5 and output coil 7 and the capacitance of the trimmer capacitor 6 perform a tuning operation of the ultrahigh frequency frequency. Then, the ultrahigh frequency output of the output coil 7 is supplied to a conductor 9 for obtaining a medical effect, and as shown in FIG. 2, the ultrahigh frequency wave is irradiated from the conductor 9 to the affected part of the human body.

The capacitance of the conductor 9 is C _D =ε ₀ ×ε×s/d (ε ₀ : permittivity, ε : relative permittivity of human body, s : conductor area,
d: distance between conductors), internal resistance R _D =
As determined by γ ₀ ×d/S (γ ₀ : specific resistance of the human body), impedance increases in proportion to the distance between the conductors 9, and increases in inverse proportion to the area of the human body (conductor area/width). Become. Normally, the output voltage of the output coil 7 is approximately constant (V _L ), so as the impedance increases, the microwave current decreases (i _RF =V _L /Z), and the thermal effect decreases.

As seen in the equivalent circuit of the human body in Figure 3, γ ₁
The heat generation due to the pure resistance of and γ ₂ is expressed as the thermal effect of the human body. For a constant microwave current, P _D = i ² _RF
× (γ ₁ + γ ₂ ), when (γ ₁ + γ ₂ ) becomes larger, the power
P _D becomes larger. However, the distance between the conductors 9 becomes longer, and the power per length remains the same (γ ₁ and γ ₂ per length of the human body do not change). Therefore, by supplying a constant ultrahigh-frequency current, a constant heat increase can be observed regardless of the length.

In this detection method, a detection coil 8 is inserted between the conductor 9 and the output coil 7, and the output voltage is rectified and smoothed by a diode 14 and a capacitor 13 to become a DC voltage. When the DC voltage reaches a constant voltage through the resistors 11 and 12 and the transistor 10, the power supply voltage of the oscillation circuit 1 is lowered by the voltage drop of the resistor 3 as a conductive state, and the ultrahigh frequency output is lowered. Control the output. Through the above process, a constant ultrashort wave current can be supplied to the conductor 9.

According to the present invention, even if there are changes in the impedance of capacitance and internal resistance due to differences in the way the conductor is held or the location (thickness, width) of the affected part of the human body, the thermal effect can be maintained at an appropriate value using a constant ultrahigh-frequency current. It can be done. Further, it is possible to eliminate the need for human operations and prevent damage to the matching of the output transistors due to erroneous operations.

[Brief explanation of drawings]

FIG. 1 is an electrical circuit diagram of an ultrashort wave treatment device according to an embodiment of the present invention, FIG. 2 is an explanatory diagram showing the operation of the same treatment device, and FIG. 3 is an equivalent circuit diagram of a human body. 1...Oscillation circuit, 9...Conductor, 10...Transistor, 13, 14...Capacitor/diode for rectification and smoothing.

Claims (1)

[Claims] 1 an oscillation circuit that generates an ultrahigh frequency output;
A power amplification transistor to which the ultrahigh frequency signal from this oscillation circuit is input to the gate and amplifies the power of the signal, and a power amplification transistor to which the output signal of this power amplification transistor is input and whose output side irradiates the human body with ultrasonic power. An output coil to which the conductor is connected, a detection means for detecting the ultrahigh-frequency current supplied to the conductor, and a DC voltage obtained by rectifying and smoothing the current detected by the detection means are applied, and the DC voltage is An ultrashort wave treatment device comprising: a transistor that becomes conductive when a constant voltage is reached and controls the power supply voltage of the oscillation circuit to change the oscillation voltage output.