JP5824801B2 - Biological tissue stimulator - Google Patents

Description

  The present invention relates to a biological tissue stimulation apparatus for applying electrical stimulation to a part of biological tissue.

  Stimulation electrodes for living tissues, such as artificial middle ears for transmitting sound vibrations to the patient's ossicles, cardiac pacemakers that are implanted in the patient's chest and suppress the occurrence of arrhythmia by applying electrical stimulation to the heart Hereinafter, research on a biological tissue stimulating device in which an electrode) is implanted in the body and a part of the biological tissue is electrically stimulated has been studied. In recent years, there has been known a visual regeneration assisting device that attempts to regenerate vision by outputting electrical stimulation pulse signals (charges) from electrodes and electrically stimulating cells constituting the retina as such a biological tissue stimulating device. (For example, refer to Patent Document 1).

  Further, in the living tissue stimulating device of Patent Document 1, a receiving unit that receives power (information) supplied from an extracorporeal device in order to make the portion directly attached to the patient's eye of the intracorporeal device implanted in the body as small as possible. And a stimulation unit for outputting stimulation current (bipolar pulse signal) from a large number of electrodes to electrically stimulate cells constituting the retina are individually attached to a living body. The receiving unit and the stimulation unit are each sealed with a known hermetic seal. As a result, invasion of body fluid is prevented, and electrical influences generated from each unit are prevented from affecting the living body. On the other hand, the receiving unit and the stimulation unit are electrically connected via a plurality of cables (conductive wires) wired in the living body, and AC power is supplied from the receiving unit to the stimulation unit via the cable. .

2010-187747

  However, in the configuration in which the cable is directly placed in the living body as in the prior art, the influence of noise generated when AC power passes through the cable is directly given to the living body. In particular, when AC power is constantly supplied from the receiving unit to the stimulation unit in order to maintain the state of the stimulation unit, the influence on the living body due to noise and leakage current generated from the cable becomes large.

  An object of the present invention is to provide a living tissue stimulating apparatus that can efficiently supply power while having little influence on the living body in view of the problems of the conventional technology.

  In order to solve the above problems, the present invention is characterized by having the following configuration.

(1) A plurality of electrodes are installed in a patient's living body, a predetermined electrical stimulation pulse signal is output from the electrodes, and a living tissue is stimulated, and AC power for driving the stimulation unit is supplied. In a biological tissue stimulating apparatus comprising an AC power source and a cable for electrically connecting the AC power source and the stimulation unit, the stimulation unit distributes an electrical stimulation pulse signal to a number of stimulation electrodes. A multiplexer having a demultiplexer function, which sets distribution of electrical stimulation pulse signals to the plurality of stimulation electrodes based on a control signal input via the cable , and for stably operating the multiplexer comprising of a power supply circuit, a power supply circuit of said stimulation unit is an AC power to be subjected fed via the cable , Driven by AC power intermittently supplied in accordance with the control timing of the multiplexer by the control signal .
(2) In the living tissue stimulating device according to (1), the stimulation unit is connected to the rectifier circuit that rectifies the AC power into DC power, and is connected to the power supply circuit and is charged by the DC power generated by the rectifier circuit. A capacitor that is charged when the AC power is supplied from the AC power source and has a predetermined potential, and when the AC power is not supplied, the capacitor is charged with the charging voltage of the stimulation unit. The state is maintained.
(3) In the biological tissue stimulating device according to (2), the stimulation unit is based on a switch for switching presence / absence of connection between the power supply circuit and the capacitor and presence / absence of supply of the AC power from the AC power supply. A first control unit for controlling operation of the switch, and the first control unit turns on the switch to charge the capacitor when the AC power is supplied from the AC power source to the stimulation unit. The switch is turned off when the AC power is not supplied, and the state of the stimulation unit is maintained at the charging voltage of the capacitor.

  ADVANTAGE OF THE INVENTION According to this invention, the stimulation unit for biological tissues which can perform an electric power supply efficiently with little influence on a biological body, and a biological tissue stimulation apparatus provided with the same can be provided.

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a circuit block diagram of a biological tissue stimulation apparatus 100. The biological tissue stimulating device 100 of the present embodiment generates information (control signal) that is arranged outside the body of a patient and is necessary for electrical stimulation of the biological tissue, and uses electric power for driving the entire biological tissue stimulating device 100. The system includes an extracorporeal device 100a to be supplied and an intracorporeal device 100b that is placed in the patient's body and performs electrical stimulation of the patient's biological tissue based on the power and information supplied from the extracorporeal device 100a.
In the present embodiment, an extracorporeal device control unit for performing drive control of the entire extracorporeal device 100a and an intracorporeal device control unit for performing drive control of the entire intracorporeal device 100b are prepared. The in-vivo device control unit includes a stimulation control unit (first control unit) for performing drive control of the entire stimulation unit 200, and a reception control unit (second control unit) for performing drive control of the entire reception unit 110. It consists of. In addition, illustration of each control part is abbreviate | omitted.

  The extracorporeal device 100a includes a signal generator 101 for generating a control signal (for example, electrode designation signal data, electrical stimulation pulse signal data, etc.) for operating the intracorporeal device 100b, and an AC power An AC power source 102, a modulation circuit 103 that modulates AC power based on a control signal to generate an electromagnetic wave, and a transmission coil L10 that transmits the electromagnetic wave output from the modulation circuit 103 to the in-vivo device 100b side. . A known modulation method such as amplitude modulation or frequency modulation is used as a modulation method from AC power to electromagnetic waves by the modulation circuit 103. Thereby, transmission / reception of electromagnetic waves is suitably performed by the coil link.

  The internal device 100b receives an electromagnetic wave supplied from the external device 100a, and outputs a receiving unit (power supply unit) 110 that extracts power and a control signal, and an electrical stimulation pulse signal for performing electrical stimulation to a living tissue. It comprises the stimulation unit 200 to be made. In addition, the receiving unit 110 and the stimulation unit 200 are electrically connected by a cable 120 that is a power transmission unit in which a plurality of conductive wires are combined.

  The reception unit 110 includes a reception coil L20 that receives an electromagnetic wave transmitted from the transmission coil L10, a demodulation circuit 111 for demodulating the electromagnetic wave, and a control signal (for example, electrode designation signal data, And a period modulation circuit 112 that generates a period modulation wave from electric power.

  Specifically, the AC power and the control signal are obtained by the demodulation circuit 111 demodulating the electromagnetic wave received by the receiving coil L20. The AC power obtained by demodulation is rectified to DC power by a rectifier circuit (not shown). This direct current power is used not only for driving the receiving unit 110 itself but also for operating a decoder for generating an electrical stimulation pulse signal (stimulation current) output from an electrode 271 described later. Further, when it is necessary to change the state of the stimulation unit 200, such as when switching the electrode that outputs the electrical stimulation pulse signal or when changing the output condition of the electrical stimulation pulse signal, the periodic modulation wave is generated by the periodic modulation circuit 112. Generated and supplied from the period modulation circuit 112 to the stimulation unit 200 via the cable 120.

  In the period modulation, a control signal represented by a binary number (0, 1) is converted into a combination of waveforms for each period with different periods (for example, 1.0 μs and 0.9 μs). Therefore, compared with amplitude modulation that transmits the control signal as amplitude change of the waveform, frequency modulation that converts the frequency change of the carrier wave and transmits, periodic modulation can shorten the transmission time of the control signal, and power transmitted to the cable The amount can be reduced.

  The cable 120 is formed of a plurality of conductive wires (wires) made of a noble metal with good biocompatibility, such as platinum, platinum iridium, stainless steel, titanium, etc., and an insulating resin with good biocompatibility, such as silicone, parylene, etc. It is formed by being bundled together by a tube. In addition, as the conducting wire, a conducting wire for transmitting electric power of the electrical stimulation pulse signal, a conducting wire pair for transmitting a periodic modulated wave generated by periodic modulation, and the like are prepared. Each conductive wire itself is coated with a resin having a good biocompatibility such as the above-mentioned parylene and having an insulating property. And since the electric power transmitted to the cable 120 is a periodic modulated wave (AC power), even when the insulation performance of the cable is lowered, electrolysis of body fluids and the like is less likely to occur.

  In this embodiment, the clock signal is generated using the period of the waveform of the periodically modulated wave (detailed configuration will be described later). This eliminates the need for providing a separate configuration for generating a clock signal for driving control, thereby contributing to downsizing and low power consumption of the apparatus. That is, other modulation schemes such as amplitude modulation in which power transmission efficiency decreases at the timing when the amplitude decreases, and frequency modulation or phase modulation that requires a configuration for generating a reference clock signal on the stimulation unit 200 side Compared to the above, the periodic modulation suitably generates a clock signal with a simpler configuration.

  The receiving unit 110 configured as described above is embedded in the temporal region. On the other hand, the stimulation unit 200 is placed on the sclera side, for example, and electrically stimulates the cells constituting the retina E1 from the sclera side (not shown). The receiving unit 110 and the stimulation unit 200 are separated from the living tissue by a known hermetic seal, and even if AC power (periodically modulated wave) is supplied to each of the receiving unit 110 and the stimulation unit 200, The effects of noise and leakage current are less likely to occur.

  On the other hand, the cable 120 is extended from the connection position with the receiving unit 110 under the skin toward the patient's eye along the temporal region, and then is inserted into the eye socket through the inside of the patient's upper eyelid. Since the cable 120 is connected to the stimulation unit 200 through the outer side of the sclera (not shown), the cable 120 is required to be thin and flexible, and like the receiving unit 110 and the stimulation unit 200, hermetic. It is difficult to prevent noise and leakage current generated by the supply of AC power (periodically modulated wave) from being applied to the living body.

  The stimulation unit 200 generates a clock signal for synchronizing the stimulation unit 200 while extracting the control signal from the power detection circuit 210 that detects the amplitude of the periodic modulation wave supplied from the reception unit 110 and the periodic modulation wave. Signal generating circuit 220, a rectifying circuit 230 for rectifying periodic modulated waves (AC power) into DC power, and a stabilized power supply circuit that smoothes the power rectified by the rectifying circuit 230 and stabilizes the potential of the DC power (Power supply circuit) 240 and a command signal (electrode designation signal, etc.) based on a control signal (electrode designation signal data, electrical stimulation pulse signal data, etc.) driven by the power supply circuit 240 and extracted by the signal generation circuit 220 , An electrical stimulation pulse signal), and the output from each electrode 271 based on a command signal from the control circuit 250. A multiplexer (demultiplexer) 260 which controls the electrical stimulation pulse signals, and a substrate 270. in which a plurality of electrodes 271 are formed to be individually connected to the multiplexer 260 at conductor illustration is omitted.

  The power detection circuit 210 is composed of a known comparator, and is connected to the cable 120 to detect the presence or absence of the amplitude of the periodically modulated wave. The output of the power detection circuit 210 is connected to the switches SW1 and SW2. The stimulus control unit switches each of the switches SW1 and SW2 between ON and OFF depending on whether or not the amplitude of the periodically modulated wave is detected. Specifically, the stimulus control unit turns on the switches SW1 and SW2 when a periodic modulated wave is detected. On the other hand, when no periodic modulation wave is detected, the switches SW1 and SW2 are turned off.

  The rectifier circuit 230 is configured by a bridge circuit using a rectifier element such as a known diode or thyristor, and is connected to the cable 120. The output of the rectifier circuit 230 is input to the power supply circuit 240 via the switch SW1, and the output of the rectifier circuit 230 is connected to the multiplexer 260 to supply power. Further, a capacitor C1 is prepared between the output side of the rectifier circuit 230 and the input side of the power supply circuit 240, and to the power supply circuit 240 (rectifier circuit 230) of the capacitor C1 by the ON / OFF switching operation of the switch SW1. The connection of can be switched. That is, when the switch SW1 is turned on when the periodic modulation wave is supplied, the capacitor C1 is charged by the DC power rectified by the rectifier circuit 230 and has a predetermined potential. On the other hand, when the periodic modulation wave is not supplied, the switch SW1 is turned OFF, so that the state of the stimulation unit 200 is held by the charging potential of the capacitor C1.

  The power supply circuit 240 is composed of a smoothing capacitor or the like, and stabilizes the DC power from the rectifier circuit 230 at a constant value. Such a power supply circuit 240 is used as a power supply for the stimulation unit 200 as a whole, and stabilizes the operation of the stimulation unit 200 (control circuit 250, signal generation circuit 220, etc.). The output of the power supply circuit 240 is connected to the control circuit 250. Further, a capacitor C2 is provided on the output side of the power supply circuit 240, and the presence / absence of connection to the power supply circuit 240 (control circuit 250) is switched by the ON / OFF switching operation of the switch SW2. As a result, the switch SW2 is turned ON when the periodic modulation wave is supplied, so that the capacitor C2 is charged with the DC power of the power supply circuit 240 and has a predetermined potential. On the other hand, when the periodic modulation wave is not supplied, the switch SW2 is turned OFF, so that the state of the stimulation unit 200 is held by the charging potential of the capacitor C2.

  As described above, when the periodic modulated wave is supplied to the stimulation unit 200, the two capacitors C1 and C2 are charged, and when the periodic modulated wave is not supplied, the state of the stimulation unit 200 is determined by the charged potentials of the two capacitors C1 and C2. By maintaining the state, the state of the stimulation unit 200 (multiplexer 260) is maintained regardless of whether power is supplied to the stimulation unit 200 or not.

  That is, since the state of the stimulation unit is held by the power that is intermittently supplied only when the state of the multiplexer 260 changes, it is not necessary to supply power only to hold the state of the stimulation unit 200. As a result, the electric power applied to the cable 120 can be reduced, and the risk of occurrence of noise or leakage current is reduced. In addition, the power supplied from the extracorporeal device 100a is used efficiently.

  The control circuit 250 is driven by DC power supplied from the power supply circuit 240 and generates a command signal (electrode designation signal or the like) based on the control signal (electrode designation signal data or the like) extracted by the signal generation circuit 220. The generated command signal is a signal for controlling the operation of the multiplexer 260.

  Next, the configuration of the signal generation circuit 220 will be described. FIG. 2 is an explanatory diagram of the configuration of the signal generation circuit. The signal generation circuit 220 shapes the waveform of the periodically modulated wave to extract a waveform for each period, and detects a period (for example, rising / falling) of the periodically modulated wave to generate a clock signal. ) 221, three period / voltage conversion circuits 223 (223 a, 223 b, 223 c) for converting the period of the periodic modulated wave extracted by the comparator 221 into a voltage, and among the three period / voltage conversion circuits 223 Based on the comparator 224 composed of three window comparators 224a to 224c for comparing the detection results from the two conversion circuits detected in succession, the output signal from the comparator 224, and the clock signal generated by the comparator 221 And a signal generation unit 225 that generates a binary control signal (electrode designation signal data or the like).

  Note that the connection state of the comparator 221 and each of the period / voltage conversion circuits 223a to 223c is sequentially switched by a switch SW3. The output of the comparator 221 is also connected to the signal generation unit 225, so that the signal generation unit 225 generates a control signal based on the clock signal. Two period / voltage conversion circuits are connected to each of the window comparators 224a to 224c. Specifically, the period / voltage conversion circuits 223a and 223b are connected to the window comparator 224a, the period / voltage conversion circuits 223b and 223c are connected to the window comparator 224b, and the period / voltage is connected to the window comparator 224c. Conversion circuits 223c and 223a are connected. In addition, the connection states of the window comparators 224a to 224c and the signal generator 225 are sequentially switched by a switch SW4. Note that the switching timing of the switches SW3 and SW4 is based on the clock signal generated by the comparator 221.

  With the configuration as described above, when a waveform of one cycle is detected by waveform shaping of the periodically modulated wave by the comparator 221, the period information for one waveform extracted by the comparator 221 is converted into a voltage converted by the switch SW3. The voltage information is converted by the circuit 223 (the circuit 223a is connected in FIG. 2). Specifically, the voltage conversion circuit 223 includes a capacitor, and the capacitor is charged to a predetermined potential according to the waveform cycle (the potential is determined for each cycle). The obtained potential information is input to the window comparator 224. Then, the signal generation unit 225 generates a control signal based on the output of the window comparator 224.

  Further, the stimulus control unit performs the switching operation of the switches SW3 and SW4 based on the clock signal. The clock signal generated by the comparator 221 is a synchronization signal necessary for the stimulus control unit and control circuit 250 to control the drive of the stimulus unit 200.

  With the configuration as described above, a control signal and a clock signal are easily generated using the period of one waveform of the periodically modulated wave extracted by the comparator 221 of the signal generation circuit 220. As a result, it is not necessary to provide a circuit for generating a separate clock signal, which is advantageous for downsizing the in-vivo device, and power is efficiently used in the stimulation unit 200 operated with a limited power supply. Become so.

  Here, the operation of the signal generation circuit 220 will be described in detail. For example, in the first clock signal, the switch SW3 is connected to the period / voltage conversion circuit 223a and the switch SW4 is connected to the window comparator 224b under the control of the stimulus control unit. Then, the waveform of one period of the periodic modulation wave extracted by the comparator is input to the period / voltage conversion circuit 223a, converted into voltage information for one period, and input to the window comparator 224a.

  Next, the stimulus control unit connects the switch SW3 and the voltage conversion circuit 223b with the next clock signal generated by the comparator 221, and connects the switch SW4 and the window comparator 224c. The voltage information for the next period converted by the period / voltage conversion circuit 223b is similarly input to the window comparator 224a. As described above, when voltage information for two cycles is input to one window comparator 224a, the window comparator 224a detects whether there is a difference in later voltage information (period information) with respect to the previous voltage information (period information). Then, a control signal is generated. For example, the control signal is generated as “0” when there is a change in voltage (when the period of the detection waveform is different), and “1” when there is no change in the voltage (when the period of the detection waveform is the same). To do. Then, when the switch SW4 is connected to the window comparator 224a by the next clock signal generated by the comparator 221, the detection result of the window comparator 224a is output to the signal generator 225 by the stimulus control unit. In the signal generation unit 225, in a state where the switching operation of the switch SW4 based on the clock signal is sufficiently completed, the binary control signal “0” or “1” extracted by the window comparator 224a is used for controlling the operation of the multiplexer. At any time, the data is transmitted to the control circuit 250.

  By repeating the operations as described above and switching the operations of the switches SW3 and SW4 based on the clock signal, information (potential information) for each period of the periodically modulated wave generated by the periodic modulation is displayed in each window comparator 224a. ˜224c is input by two waveforms. And a control signal comes to be extracted by the presence or absence of the change of the voltage information for two waveforms.

  The control circuit 250 generates a command signal by collecting the binary control signals transmitted from the signal generation unit 225 with a predetermined number of bits. Then, the stimulus control unit performs control to switch the state of the multiplexer 260 based on the command signal generated by the control circuit 250. The command signal includes a signal for switching the entire state of the multiplexer 260, a signal for designating an operating point, an electrode designation signal for designating an electrode 271 for outputting an electrical stimulation pulse signal, and the like. Then, the multiplexer 260 outputs an electrical stimulation pulse signal from, for example, a designated electrode 271 based on the command signal.

  Next, the operation of the circuit having the above configuration will be described. FIG. 3 is an explanatory diagram of the relationship between the driving state of the AC power source 112 and the state change of the multiplexer 260. Here, FIG. 3A shows the reception state of the periodic modulated wave of the stimulation unit 200 in FIG. The state change of the multiplexer 260 is shown in b). FIG. 4 is a timing chart for generating a control signal by the signal generation circuit 220. FIG. 4A shows the period of the waveform (one waveform) of the periodic modulation wave detected by the signal generation circuit 220. FIG. 4B shows a control signal generated based on the detection result of the waveform period.

  When the electromagnetic wave generated by the extracorporeal device 100a is transmitted from the transmission coil L10 and received by the receiving coil L20 (reception unit 110) of the intracorporeal device 100b, the electromagnetic wave is demodulated by the demodulation circuit 111, and AC power and a control signal are generated. can get. Then, when the state of the stimulation unit 200 is switched, the period modulation circuit 112 generates a period modulation wave based on the control signal. Then, only when the stimulation unit 200 is switched, the periodically modulated wave is supplied to the cable 120 as electric power for driving the stimulation unit 200. As a result, the influence of noise on the living body can be suppressed, and AC power can be used efficiently in the in-vivo device 100b.

  On the other hand, on the stimulation unit 200 side, the power detection circuit 210 detects the presence or absence of the amplitude of the periodically modulated wave. Here, when the waveform of the periodically modulated wave is extracted at time t1, the switches SW1 and SW2 are turned ON, the periodically modulated wave is rectified by the rectifier circuit 230, the capacitor C1 is charged, and the potential of the power supply circuit 240 is increased. The capacitor C2 is charged and has a predetermined potential. In addition, the multiplexer 260 is driven by the rectifier circuit 230, and the entire stimulation unit 200 including the control circuit 250 and the multiplexer 260 is driven by the power supply circuit 240.

  On the other hand, in the signal generation circuit 220, after the time t1, the comparator 221 extracts the period of the waveform for each period of the period modulation wave and generates the clock signal. Then, a control signal is generated by comparison before and after the period of the waveform continuously extracted by the comparator 221. In FIG. 4A, the period A is the period when the period of the waveform detected by the signal generation circuit 220 is 1.0 μs, and the period B is the case where the period is 0.9 μs. In addition, as shown in FIG. 4B, in this embodiment, “1” is output when the preceding and following waveforms have the same period, and “0” is output when the preceding and following waveforms have different periods. However, the method of generating the control signal by the signal generation circuit 220 is an example, and “1” is output when the periods of the preceding and succeeding waveforms are different, and “0” is output when they are the same. Good. In this embodiment, since the control signal is generated based on the comparison result of the period of two waveforms, in FIG. 4B, the control signal is output with a delay of two clocks. The generation of the control signal and the clock signal is continuously performed until the waveform of the periodically modulated wave is not detected at time t2.

  When the control signal (command signal) extracted as described above is input to the control circuit 250, the control circuit 250 collects binary information that is sequentially received into one command signal. Then, the stimulus control unit switches the state of the multiplexer 260 based on the command signal generated by the control circuit 250. Then, the multiplexer 260 performs operation control for outputting an electrical stimulation pulse signal from the designated electrode 271 based on the command signal.

  On the other hand, when the periodic modulated wave is no longer detected at time t2, the stimulus control unit turns off the switches SW1 and SW2 by driving the power detection circuit 210. As a result, the circuit of the stimulation unit 200 is opened, and the state of the stimulation unit 200 (the control circuit 250 and the multiplexer 260) is held by the potentials of the capacitors C1 and C2 (see FIG. 3). That is, the state of the stimulation unit 200 is maintained even when there is no power supply from the receiving unit 110.

  Similarly, when the state of the multiplexer 260 is switched during the supply of the periodic modulated wave (AC power) between time t3 and t4, and the amplitude of the waveform of the periodic modulated wave is not detected after time t4, the capacitors C1 and C2 The states of the control circuit 250 and the multiplexer 260 are held by the potential. As a result, the power supplied to the in-vivo device 100b can be used efficiently.

  Next, a case where the biological tissue stimulating apparatus having the above-described configuration is used as a visual reproduction assisting apparatus that reproduces part or all of a patient's vision will be described as an example. FIG. 5 is a block diagram of a control system of the visual reproduction assisting device. In addition, the same figure number is attached | subjected and demonstrated to the same structure as said biological tissue stimulation apparatus 100. FIG.

  The visual reproduction assisting device 1 includes an extracorporeal device 1a for photographing the outside world, and an in-vivo device 1b that applies electrical stimulation to the cells (see FIG. 5) constituting the retina E1 to promote visual reproduction. The extracorporeal device 1a uses, as control signals, a spectacle-shaped visor (not shown) worn by a patient, a photographing device 3 including a CCD camera attached to the visor, and a subject image (image data) photographed by the photographing device 3. A signal generator 101 for conversion, an AC power source 102 for supplying power to the in-vivo device 1b, a modulation circuit 103 for modulating AC power based on a control signal, and image data and power generated by the extracorporeal device 1a Is configured with a transmission coil L10 and the like. A magnet (not shown) is attached to the center of the transmission coil L10, and is used to fix the position with the reception coil L20 on the intracorporeal device 1b side described later.

  The in-vivo device 1b includes a receiving unit 110 that generates electric power and a stimulation signal from the electromagnetic wave received by the receiving coil L20, and a stimulation unit that electrically stimulates cells constituting the retina E1 with electric stimulation pulse signals output from the plurality of electrodes 271. 200 is connected via a cable 120. In addition, the diameter of the cable 120 of this embodiment is made thin, and it arrange | positions suitably along a patient's eyeball.

  When switching the state of the stimulation unit 200 (multiplexer 260), the reception unit 110 periodically modulates a part of the obtained electric power to generate a periodic modulated wave, and sends it to the stimulation unit 200 via the cable 120. That is, AC power is efficiently supplied to the stimulation unit 200 (multiplexer 260) only when the state is switched.

  The operation of the visual reproduction assisting apparatus 1 having the above configuration will be described. A subject image (image data) photographed by the photographing device 3 is converted into a control signal by the signal generation unit 101. Then, the modulation circuit 103 modulates the amplitude of the AC power from the AC power source 102 based on the control signal to generate an electromagnetic wave. The transmission coil L10 transmits the generated electromagnetic wave to the in-vivo device 1b side.

  On the in-vivo device 1b side, the electromagnetic wave received by the receiving coil L20 is demodulated by the receiving unit 110 to generate power and a control signal. At this time, the generated power is used for the electrical stimulation pulse signal output from the electrode 271 and the operation of the receiving unit 110 itself. Then, only when the state of the stimulation unit 200 is switched, a part of the power is periodically modulated based on the control signal (electrode designation signal data) and transmitted as a periodically modulated wave. That is, a periodic modulated wave (AC power) is intermittently supplied to the cable 120 (only when necessary).

  On the other hand, on the stimulation unit 200 side, the control signal and the clock signal are extracted from the periodically modulated wave, and the command signal is generated, whereby the state of the multiplexer 260 is switched and the remaining power obtained by the receiving unit 110 is used. The generated electrical stimulation pulse signal is output from the electrode 271. Further, on the stimulation unit 200 side, the power of the periodically modulated wave is used (a capacitor (not shown) is charged, and the state is maintained regardless of whether power is supplied).

  As described above, since the periodic modulation wave (AC power) is efficiently supplied via the cable only when the state of the stimulation unit is switched, the influence of noise on the living body can be suppressed and the generation of leakage current Risk can be reduced and the reliability of the device is improved.

  In addition, since the clock signal is generated using the period of the waveform of the periodically modulated wave, it is not necessary to separately provide a circuit for generating the clock signal on the stimulation unit side, which is advantageous for downsizing the stimulation unit. In addition, power is efficiently supplied to the multiplexer and the like.

  Furthermore, in the present embodiment, power, a control signal, and further a clock signal are obtained simultaneously by transmission of a periodically modulated wave generated by periodic modulation. Therefore, since these pieces of information are transmitted by a pair of conducting wires, the number of wires in the cable can be reduced. As a result, the flexibility of the cable is improved, and the cable can be suitably placed in the patient's body.

  In the present embodiment, power is supplied from the external AC power source to the in-vivo device, but the present invention is not limited to this. Even when a power source is provided in the in-vivo device, the present invention is applied to suppress the influence on the living body, so that the power can be used efficiently, and the living tissue stimulating device is long in the living body. The period is preferably used.

It is a circuit block diagram of the stimulation apparatus for biological tissues. It is explanatory drawing of a structure of a signal generation circuit. It is explanatory drawing of the relationship between the drive state of alternating current power supply, and the state change of a multiplexer. It is a timing chart of control signal generation by a signal generation circuit. It is a block diagram of the control system of a visual reproduction auxiliary device.

DESCRIPTION OF SYMBOLS 100 Biological tissue stimulating device 100a External device 100b In-vivo device 110 Receiving unit 112 Periodic modulation circuit 120 Cable 200 Stimulation unit 210 Power detection circuit 220 Signal generation circuit 221 Comparator 223 Period / voltage conversion circuit 224 Window comparator 225 Signal generation unit 230 Rectification circuit 240 power supply circuit 250 control circuit 260 multiplexer 270 substrate 271 electrode

Claims (3)

A stimulation unit that installs a plurality of electrodes in a living body of a patient and outputs a predetermined electrical stimulation pulse signal from the electrodes to stimulate living tissue, and an AC power source that supplies AC power for driving the stimulation unit A biological tissue stimulating device comprising: a cable for electrically connecting the AC power source and the stimulation unit;
The stimulation unit is a multiplexer having a demultiplexer function for distributing electrical stimulation pulse signals to a plurality of stimulation electrodes, and the electrical stimulation for the plurality of stimulation electrodes is performed based on a control signal input via the cable. A multiplexer for setting the distribution of the pulse signal , and a power supply circuit for stably operating the multiplexer,
Power supply circuit of said stimulation unit is an AC power to be subjected fed via the cable, characterized in that it is driven by the AC power is intermittently supplied in accordance with the timing of the control of the multiplexer by the control signal A biological tissue stimulating device. The biological tissue stimulating apparatus of claim 1,
The stimulation unit includes a rectifier circuit that rectifies the AC power into DC power, and a capacitor that is connected to the power supply circuit and is charged by the DC power generated by the rectifier circuit,
The capacitor is charged when the AC power is supplied from the AC power source and has a predetermined potential. When the AC power is not supplied, the capacitor holds the state of the stimulation unit at the charging voltage. A biological tissue stimulating device. The biological tissue stimulating device according to claim 2,
The stimulation unit includes a switch for switching presence / absence of connection between the power supply circuit and the capacitor, and a first control unit for controlling operation of the switch based on presence / absence of supply of the AC power from the AC power supply. And comprising
The first control unit turns on the switch to charge the capacitor when the AC power is supplied from the AC power source to the stimulation unit, and turns off the switch when the AC power is not supplied. A living tissue stimulating device, characterized in that the state of the stimulation unit is maintained by a charging voltage.

Images