JPH0243508B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention applies two or more distributed alternating currents with a frequency of several thousand Hz or more to a common local tissue of the human body, thereby generating interference waves in the local tissue to generate low-frequency stimulation. This invention relates to an electrical stimulation device that provides

Conventionally, the above-mentioned electrical stimulation device applies distributed currents of two sinusoidal alternating currents of about 4000 Hz, which have a frequency difference corresponding to the low frequency to be stimulated, spatially intersecting the local tissue to be treated. It has been common practice to apply low-frequency stimulation to the local tissue through mutual interference of distributed alternating currents.

In the case of such a conventional electric stimulation device, since it utilizes the interference effect of the distributed current of two sine wave alternating currents, it requires two oscillators with an oscillation frequency of several thousand Hz or more. In particular, when it is desired to apply ultra-low frequency stimulation to the local tissue to be treated, the stability of the two oscillators must be kept sufficiently high, which complicates the circuit configuration and also prevents such interference effects. The method used to obtain the low-frequency stimulation had the disadvantage that only a sinusoidal waveform could be obtained.

It is an object of the present invention to provide an electrical stimulation device that eliminates these drawbacks and allows a greater variety of stimulation effects to be obtained. Hereinafter, embodiments will be described in detail based on the drawings.

FIG. 1 is a block diagram of one embodiment of the present invention. In the figure, 1 is an oscillator, 2 is a buffer amplifier, 3 is a phase modulator, 4 is a low frequency arbitrary waveform generator, 5 and 6 are power amplifiers, 7 and 8 are output transformers, 9, 9', 10, 10' is an electrode, and 11 is a common local tissue of the human body.

When an oscillation output of 4000 Hz is generated in the oscillator 1, the output of the buffer amplifier 2 due to this oscillation output is applied to the electrodes 9, 9' via the power amplifier 5 and the output transformer 7 as a steady phase wave. The output of the buffer amplifier 2 is also applied to a phase modulator 3, where it is phase-modulated with a constant amplitude by a low-frequency arbitrary waveform signal from a low-frequency arbitrary waveform generator 4. The phase modulated wave generated by the phase modulator 3 is applied to the electrodes 10, 10' via a power amplifier 6 and an output transformer 8. In this case, the two output transformers 7 and 8 produce a steady phase output and a phase modulated output, respectively, of a magnitude suitable for treatment. Further, as shown in the figure, the electrodes 9, 9' and the electrodes 10, 10' are connected to the common local tissue 11 so that the distributed current due to the steady phase output and the phase modulated output is applied as orthogonally to the common local tissue 11 to be treated. It should be placed around the .

In addition, the output frequency of the oscillator is usually 1KHz ~
A range of 10KHz is applied, but higher frequencies can be applied depending on the treatment area.

FIG. 2 is a circuit diagram in which a phase modulator 20 that performs two-phase phase modulation with a low-frequency square wave is applied as an implementation example of the modulator shown in FIG. 1.

3a to 3d show the signal waveforms of each portion of FIG. 2 with corresponding alphanumeric symbols.

Buffer amplifier 2 is activated by the sine wave output of oscillator 1.
The output has the waveform shown in FIG. 3a, and this output is applied to the phase modulator 20.

In the phase modulator 20, this input signal is
As shown in Figure b, the inverting amplifier 21 inverts the
The phase shifts by 180°. The flip-flop 22 is
The switch 24 is used to select either the input signal or the phase-inverted output signal of the inverting amplifier 21 at a timing when the input signal is at zero potential. That is, the output pulse of the comparator 23, which detects the point where the input signal crosses zero potential, is applied to the clock input terminal of the flip-flop 22, while the low frequency arbitrary waveform shown in FIG. 1 is applied to the data input terminal. Square wave generator 2 corresponding to generator 4
A square wave pulse shown in FIG. 3c from 5 is applied.

When the state of the data input changes to "1" or "0", the output of the flip-flop 22 changes in synchronization with the clock change timing, and the switch 24 is driven.

Both the phase modulator input signal and the inverting amplifier output signal are applied to the switch 24, and depending on the output state of the flip-flop 22, either input is grounded. Therefore, the signal that is not grounded is input to the mixing amplifier 25.

The mixed amplifier output becomes a two-phase phase modulated signal as shown in the waveform shown in d of FIG. 3, and this becomes the output of the phase modulator 20.

Output signal of buffer amplifier 2 (Figure 3a)
and the phase modulator output (FIG. 3d) are input to the power amplifiers 5 and 6 in FIG. 1, respectively.

In this way, a steady phase wave is applied to the local tissue 11 by conduction via the electrodes 9, 9', and a phase modulated wave is applied to the electrode 11 so as to be substantially orthogonal to the steady phase wave.
0, 10' to the local tissue 11, the waveform of FIG. 3a and the waveform of FIG.
1, synthetic waves x and x' are generated in the local tissue 11, as shown in FIGS. 4 and 5 a and b,
The envelope waves y, y' are waveforms of changes in the strength of the average current corresponding to the square wave of the low frequency arbitrary waveform generator 4, and this becomes a low frequency stimulation of the local tissue 11.

Note that the magnitude relationship of the current distribution from both electrode pairs differs depending on the local tissue, and when they are the same, the waveform will be as shown in FIG. 5a, but generally the waveform will be as shown in FIG. 5b.

In addition, in the phase modulator 3 of FIG. 1, the output of the buffer amplifier 2 as shown in FIG. 6a is phase modulated by the low frequency triangular wave shown in FIG. 6b from the low frequency arbitrary waveform generator 4. In this case, the phase modulated wave output from the phase modulator 3 has a repetitive waveform in which the phase shifts little by little and returns to the original state again, as shown in FIG. ' to add the steady phase wave shown in FIG.
By adding the phase modulated wave shown in Fig. 6c from 10', a composite wave x'' as shown in Fig. 7 is generated in the local tissue, and its envelope wave y'' becomes a sine wave, which is different from the conventional interference wave stimulation therapy device. Apply similar low-frequency stimulation to local tissue 1.
1 can be given.

In general, the envelope of the composite wave of two sine waves sinωt and sin(ωt+φ(t)) (ω is the angular frequency of the oscillation output) with a phase difference φ(t) (t-time) is 2cos(1/2φ
(t)). Therefore, by changing cos (1/2φ(t)) to a desired stimulus wave shape, stimulation with an arbitrary waveform can be obtained. Arbitrary waveform modulation signal f(t)
Create the inverse cosine function cos ^-1 f(t) and 1/2φ(t)=
By setting cos ^-1 f(t), the envelope waveform of the composite wave contributing to stimulation follows f(t), and a desired waveform can be obtained.

As is clear from the above explanation, when a steady phase wave and one phase modulated wave are applied to a common local tissue of the human body by conduction via an electrode, an electric field is generated in the local tissue due to each of these waves. are spatially synthesized, and the instantaneous amplitude difference between the waves allows low-frequency stimulation with a waveform determined by the synthesis form to be applied deep to the local tissue.
However, according to the present invention, the shape of the low-frequency stimulation can be appropriately selected depending on the symptoms such as constipation and lower back pain in the local tissue of the human body to be treated, and the stimulation can be spread from deep to the entire body. Since it is possible to make the human body feel the sensation, the applications of electrical stimulation devices that apply low-frequency stimulation to the human body can be dramatically expanded.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, in which a stationary phase wave and a modulated phase wave are caused to interfere with each other. FIG. 2 is a circuit diagram for detailed explanation of FIG. 1, and shows a case where phase modulation is performed using a low frequency square wave. 3a to 3d are the signal waveforms of each part of FIG. 2, and FIGS. 4 and 5 are the signal waveforms of FIGS. 3a and 3d spatially synthesized in the local tissues of the human body, respectively. The composite wave and its envelope wave are shown. Also, Figure 6a
-c are explanatory diagrams of other embodiments of the present invention, each waveform when one of the two waves is phase modulated with a triangular wave, and Fig. 7 is a composite wave of Fig. 6a and Fig. 6c and its waveform. Shows an envelope wave. Explanation of symbols, 1: Oscillator, 3: Modulator, 4: Low frequency waveform generator, 7, 8: Output circuit, 9, 9', 1
0, 10': electrode, 20: modulator.

Claims (1)

[Claims] 1. Stationary phase wave generation means that outputs a stationary phase wave;
A low frequency signal generating means for outputting a low frequency pulse, a modulation means for generating a phase modulated wave obtained by phase modulating the steady phase wave, and a signal by intermittently modulating the steady phase wave based on the low frequency pulse. An electrical stimulation device comprising: a pair of electrodes that output power corresponding to the output of the steady phase wave generating means; and another pair of electrodes that output power corresponding to the output of the modulating means.