JPH0326981B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a short wave therapy device that performs therapy using electromagnetic waves.

[Prior art]

Conventionally, short-wave therapy devices have been used at home, using electromagnetic waves with a frequency of approximately 10 to 50 MHz, and transmitting these electromagnetic waves to the treatment area of the human body to generate heat within the body, and utilizing the thermal effect generated by this. has been done. Such a short wave treatment device has an oscillating section and a conductor that comes into contact with the treatment area, and transmits high frequency waves output from the oscillating section to the human body as electromagnetic waves from the conductor.

By the way, in such a short wave treatment device,
It is necessary to match (impedance matching) between the oscillator and the load. Conventionally, in order to achieve matching, a variable impedance means such as a variable capacitor was inserted between the oscillating part and the conductor, and an operator operated the variable capacitor manually to achieve matching while looking at a meter. However, this method has the disadvantage that the load impedance varies in various treatment areas, and the user must manually perform matching for each site, which is cumbersome. Furthermore, even once alignment is achieved, if the human body moves during treatment, even a slight movement will change the load impedance of the treatment area. As a result, inconsistency occurs, and treatment continues with this inconsistency.
The intensity of radio wave transmission to the treatment area is affected, and the thermal effect is weakened. Furthermore, in this case, the loss of the device body increases by the amount that the transmitted intensity to the treatment site decreases. Therefore, in recent years, a short wave therapy device that can automatically perform matching has been developed (see Japanese Patent Laid-Open No. 61-20563). This device constantly detects the output current of the oscillator, and when this output current drops below a predetermined value, the variable capacitor mentioned above is automatically rotated by a motor etc. to locate the position where the output current is the highest. It will be selected automatically.

[Problem that the invention seeks to solve]

However, in the conventional device described above,
The drawbacks were that the circuit configuration was complicated and the cost was high.

This invention was made in view of the above circumstances,
The purpose is to provide a short-wave therapy device that is simple and inexpensive in construction, and is capable of automatic alignment.

[Means to solve the problem]

The present invention provides a therapeutic wave generating section that generates high frequency waves for treatment, a guide that comes into contact with a treatment site of a human body, and a guide provided between the therapeutic wave oscillating section and the guide,
a variable impedance section that performs impedance matching between the two, a quantitative change means that intermittently changes the impedance of the variable impedance section by a predetermined amount, a detection means that detects a load current flowing through the variable impedance section, and the quantitative change means. When the impedance of the variable impedance section is changed, if the load current increases, the impedance of the variable impedance section is changed in the same direction as the impedance change by the quantitative change means, and if the load current decreases, the impedance of the variable impedance section is changed in the same direction as the impedance change by the quantitative change means. and an impedance section control means for changing the impedance of the impedance section in a direction opposite to the impedance change by the quantitative change means.

[Effect]

This invention changes the impedance of a variable impedance section inserted between the oscillation section and the conductor by a fixed amount by a quantitative change means, detects whether the output current of the oscillation section increases or decreases at this time, If the impedance increases, the impedance of the variable impedance section is changed in the same direction as the impedance change direction by the quantitative change means, and if it decreases, the impedance is changed in the opposite direction to the impedance change by the quantitative change means, and the above operation is repeated. automatically adjusts the alignment.

〔Example〕

FIG. 1 is a diagram showing the basic configuration of the present invention. In this figure, reference numeral 1 denotes an oscillation section, which is composed of an oscillator 2 that generates high frequency waves for treatment and an output transformer 3. 4 is a variable capacitor,
5 is a capacitor, 6 is a switch, 7a and 7b are output terminals, and 8a and 8b are conductors connected to the output terminals 7a and 7b, respectively. The guides 8a and 8b are brought into contact with the human body so as to sandwich the treatment area.

In the above configuration, the variable capacitor 4 is for matching the load of the oscillation section 1,
Further, the series circuit of capacitor 5 and switch 6 is a circuit for detecting whether or not matching is properly achieved. The following process is used to determine whether or not there is consistency. First, switch 6
is turned on, and the output current of the oscillation section 1 before being turned on is compared with the current after being turned on. If the current increases after turning on, it is preferable to increase the capacitance of the variable capacitor in order to achieve matching. Therefore, the capacitance of the variable capacitor 4 is automatically increased by a certain amount using a motor or the like. Next, turn on the switch 9 again, compare the output current of the oscillation section 1 before turning it on with the output current of the oscillation section 1 after turning it on, and if the output current of the oscillation section 1 has increased, , the capacitance of the variable capacitor 4 is increased by a certain amount again. Further, when the switch 6 is turned on and the output current of the oscillation section 1 is decreased, the capacitance of the variable capacitor 4 is decreased by a certain amount. By repeating the above operations, the two are matched.

Next, a circuit diagram of an embodiment of this invention is shown in FIG.
Explain with reference to. Note that in this figure,
Items that are the same as those in Figure 1 are given the same reference numerals and their explanations.
omitted. In this figure, 9 is the load current of
Current detector to detect, 10 is the output of current detector 9
Diode for detecting current, 11 is diode 1
0 output load resistance, 12 smoothing capacitor, 13
is the output current detection circuit. This output current detection circuit
Line 13 is a circuit for detecting changes in load current.
The details are shown in Figure 3. In this figure 3
14 is a switch that works with switch 6.
When switch 6 is turned on, it turns off and the switch 6 turns on.
It turns on when switch 6 turns off. 15 is da
Temporarily hold the cathode voltage of ioode 10
capacitors, 16 and 17 are FETs, 1
8 and 19 are resistors, FET16 and resistor 18,
FET17 and resistor 19 each function as a buffer amplifier.
It constitutes a source follower that functions as a 20
is the source voltage of FET16 and the source voltage of FET17.
This is a differential amplifier that amplifies and outputs the voltage difference between the
The output is sent to the motor control circuit 21 shown in FIG.
and is supplied to the matching range determination circuit 25. Mo
The output value of the differential amplifier 20 is positive.
When , the motor 22 is rotated forward by a certain amount, and when it is negative, the motor 22 is rotated forward by a certain amount.
The motor 22 is reversed by a certain amount. Motor 22 is variable
The shaft of the capacitor 4 is driven to rotate. to this
Therefore, when the motor 22 rotates forward, the variable capacitor
When the capacitance of 4 increases and reverses, the variable capacitor
4 capacity decreases. 23 is astable multivibe
It is a generator that generates a pulse signal with a constant period.
Ru. The output signal of this astable multivibrator
Based on the switch 6 and switch 14 options.
On-off is performed. 25 is a matching range judgment circuit
, and the absolute value of the output of the differential amplifier 20 (Fig. 3) is
If the value is outside the predetermined range, no
Drive the stable multivibrator 23 to maintain a predetermined range.
If within, the astable multivibrator transmits.
make it stop.

Next, the operation of the above-mentioned circuit will be explained. When the operator applies the guides 8a and 8b to the treatment area of the human body and turns on the short-wave therapy device, the oscillator 2 generates a high frequency, this high frequency is output from the output transformer 3, the variable capacitor 4, and the guide 8a. , 8b to the treatment site of the human body. Also, at this time,
The multivibrator 23 starts oscillating, which turns the switches 6 and 14 on and off. First, when switch 6 is off, switch 14 is on, and the output voltage of diode 10, that is, the voltage corresponding to the load current, is applied to capacitor 15.
is stored in Next, when switch 6 is turned on,
A capacitor 5 is connected in parallel to the variable capacitor 4, increasing the circuit capacity and changing the load current.
This current is detected by the diode 10 via the output transformer 9 as described above, and is detected by the load resistor 11.
occurs as a voltage across the . This voltage is
The signal is supplied to the gate of FET 17, amplified to a gain of approximately "1" by FET 17, and supplied from the source of FET 17 to one input terminal of differential amplifier 20. At this time, the other input terminal of the differential amplifier 20 is supplied with a voltage (voltage across the capacitor 15) corresponding to the load current when the switch 6 is off.
As a result, the output of the differential amplifier 20 is
The voltage corresponds to the difference between the load current before and after the switch is turned on, and this voltage is supplied to the motor control circuit 21 and the matching range determination circuit 25. Here, if the load current increases by turning on the switch 6, the output of the differential amplifier 20 becomes a positive voltage, and this positive voltage is supplied to the motor control circuit 21. The motor control circuit 21 receives this positive voltage and causes the motor 22 to rotate forward by a certain amount. This increases the capacitance of the variable capacitor 4. On the other hand, when the load current decreases by turning on the switch 6, the output of the differential amplifier 20 becomes a negative voltage, and this negative voltage is applied to the motor control circuit 21.
supplied to The motor control circuit 21 receives this negative voltage and rotates the motor 22 in a constant reverse direction. This reduces the capacitance of the capacitor 4. Next, when switch 6 is turned off and switch 14 is turned on again, a voltage corresponding to the load current at this time is stored in capacitor 15. Next, when the switch 6 is turned on and the switch 14 is turned off, the voltage corresponding to the change in the load current is output from the differential amplifier 20, as in the case described above.
The motor 22 is driven based on the output. Thereafter, the switches 6 and 14 are turned on and off, thereby repeating the same operation as described above. Fourth
The figure shows the relationship between the capacitance Cv of the variable capacitor and the load current, and the broken line shows how the load current changes depending on whether the switch 6 is turned on or off. motor 2
2, the capacitance of the variable capacitor 4 is gradually changed and when it falls within range D (within perspective), it is determined that the absolute value of the output voltage of the differential amplifier 20 is below a certain value and matching has been achieved, and matching is achieved. Range determination circuit 25
causes the multivibrator 23 to stop oscillating.
At this time, both switches are held with switch 6 on and switch 14 off. Next, for example, if the user moves the conductors 8a, 8b and the load current changes, and the absolute value of the output voltage of the differential amplifier 20 exceeds a certain voltage, then the matching range The determination circuit 25 detects this and causes the multivibrator 23 to start oscillating again.
As a result, switch 6 and switch 14 start turning on and off, and matching is achieved in the same manner as in the case described above.

Note that as the motor 22, a pulse motor or a DC motor may be used. Further, in the case of a DC motor, the DC motor may be rotated by a certain angle using a code plate and a limit switch. Further, the capacitance of the capacitor 5 and the amount of change in the variable capacitor 4 that changes depending on the rotation of the motor 22 may be made the same.

〔Effect of the invention〕

As described above, according to the present invention, the impedance of the variable impedance section inserted between the oscillation section and the conductor is changed by a fixed amount by the quantitative change means, and at this time, the output voltage of the oscillation section is increased. detects whether the impedance has decreased, and if it has increased, changes the impedance of the variable impedance section in the same direction as the impedance change direction by the quantitative change means, and if it has decreased, changes it in the opposite direction to the impedance change by the quantitative change means, Since matching is automatically achieved by repeating the above operations, the circuit configuration is simpler and cheaper than the conventional one.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing the basic configuration of the invention, FIG. 2 is a circuit diagram showing the configuration of an embodiment of the invention, and FIG. 3 shows details of the output current detection circuit 13 in FIG. 2. The circuit diagram shown in FIG. 4 is a diagram showing the relationship between the load current and the capacitance Cv of the variable capacitor 4 in FIG. 2. 1...Treatment wave oscillation unit, 4...Variable capacitor,
5...Capacitor, 6...Switch, 8a, 8b
... Conductor, 9 ... Output transformer, 13 ... Output current detection circuit, 21 ... Motor control circuit, 22 ...
Motor, 23...Unstable multivibrator.

Claims (1)

[Scope of Claims] 1. A therapeutic wave generating section that generates high frequency waves for treatment, a guide that comes into contact with a treatment area of the human body, and a device that is provided between the therapeutic wave generating section and the guide, and that a variable impedance section that performs impedance matching; a quantitative change means that intermittently changes the impedance of the variable impedance section by a predetermined amount; a detection means that detects a load current flowing through the variable impedance section; When changing the impedance of the impedance part, if the load current increases, the impedance of the variable impedance part is changed in the same direction as the impedance change by the quantitative change means, and if the load current decreases, the A short wave treatment device comprising impedance section control means for changing the impedance of the variable impedance section in a direction opposite to the impedance change by the quantitative change means. 2. The short wave treatment device according to claim 1, wherein the variable impedance section is a variable capacitor. 3. The quantitative change means is composed of a capacitor, a switch connected in series to the capacitor, and means for intermittently turning on and off the switch, and a series connection circuit of the capacitor and the switch is connected in parallel to the variable capacitor. A short wave therapy device according to claim 2, characterized in that: 4. The short wave therapy device according to claim 3, wherein the amount of change in impedance caused by the capacitor and the amount of change in the variable capacitor that is changed by the impedance section control means are approximately the same amount. 5. The short-wave therapy device according to claim 2, wherein the variable capacitor is quantitatively changed by a pulse motor. 6. The short wave treatment device according to claim 2, wherein the variable capacitor is quantitatively changed by a DC motor. 7. The short wave treatment device according to claim 3, wherein the switch is an electromagnetic relay. 8. The short wave therapy device according to claim 3, wherein the switch is a semiconductor analog switch.