Showing papers on "Electrode array published in 1997"

Differential touch sensor and control circuit therefor

Abstract: A differential touch sensor apparatus for detecting the presence of an object such as a human appendage, the apparatus having a first electrode, a second electrode positioned proximate to the first electrode, a differential circuit connected to the first and second electrodes, and a pulse or other signal source connected to provide electrical signals that generate an electric field between the first and second electrodes. Introduction of an object near the first electrode affects the electric field between the first and second electrodes, thereby affecting the voltage difference between them. A differential circuit provides an output signal responsive to the difference in voltage between the first and second electrodes. In an alternative embodiment, a strobe electrode is provided proximate to both said first and second electrodes and the pulses or other signals are provided to the strobe electrode to induce an electric field between the strobe electrode and each of the first and second electrodes.

Variable control of electroosmotic and/or electrophoretic forces within a fluid-containing structure via electrical forces

Abstract: In a microfluidic system (partially shown by element 178 in the figure and elements thereupon) using electrokinetic forces, the present invention uses electrical current or electrical parameters, other than voltage, to control the movement of fluids through the channels of the system. Time-multiplexed power supplies (200 and 202) also provide further control over fluid movement by varying the voltage on an electrode connected to a fluid reservoir of the microfluidic system, by varying the duty cycle during which the voltage is applied to the electrode, or by a combination of both. A time-multiplexed power supply can also be connected to more than one electrode for a saving in cost.

Multiplexed active biologic array

Abstract: An improved biologic electrode array (12) and methods for using the same. Each electrode (30) in the array (12) is coupled to a respective sample-and-hold circuit (26). The electrodes (30) and sample-and-hold circuits (26) are integral and form an array (12) within a single semiconductor chip, such that each sample-and-hold circuit (26) may be loaded (37) with a predefined voltage provided by a single, time-shared digital-to-analog converter (DAC) (22). All of the sample-and-hold circuits (26) may be accessed through a multiplexer which may scan through some or all of the electrode locations (30). Each sample-and-hold circuit (26) may comprise a capacitor (32) and one or more transistor switches (34, 36), the switches (34, 36), when closed providing electrical communication between the capacitor (32) and a source line (37) formed in the matrix (12).

Electrode array system for measuring electrophysiological signals

Abstract: An array of electrodes is constructed to allow the user to easily adjust to the correct size of the patient's head. The array is self-adhesive, pre-gelled and disposable. The array fits easily over the temple and forehead areas where EEG signals can be acquired by specially designed monitors for purposes of monitoring a number of bodily phenomena, including but not limited to, depth of anesthesia, and/or ischemia, and burst suppression. The array is connected to the monitor via a tab connector that is integral to the disposable device. The tab connector is insertible into a reusable connector that is part of a monitoring system.

Dynamic heating method and radio frequency thermal treatment

Abstract: A method and system for the delivery of radiofrequency energy to the tissue, particularly, the prostate, to alleviate the symptoms of BPH is disclosed. The system incorporates a bipolar or multipolar electrode array to create an electric field where the heat created is confined solely to a specific volume of the prostate gland and therefore the heated tissue is defined only by the electrode geometry. The bipolar electrode array provides a variety of three dimensional, symmetric heating patterns within the prostatic tissue depending on the relative electrode lengths and angular separation. The system provides precision tissue temperature and impedance measurements thereby enabling the surgeon to accurately predict heating pattern performance and tissue response to RF heating.

Electric field fingerprint sensor apparatus and related methods

Abstract: A fingerprint sensor includes an array of electric field sensing electrodes, a dielectric layer on the sensing electrodes with the dielectric layer for receiving a finger adjacent thereto, and a driver for applying an electric field drive signal to the sensing electrodes and adjacent portions of the finger so that the sensing electrodes produce a fingerprint image output signal. In one embodiment of the invention, the driver provides a coherent drive signal for the array. A respective shield electrode may be associated with each of the electric field sensing electrodes for shielding each electric field sensing electrode from adjacent sensing electrodes. Each shield electrode may be actively driven for further shielding. The fingerprint sensor preferably further includes a synchronous demodulator and contrast enhancer for more accurate output image signals. The fingerprint sensor may be effectively used to control access to a computer workstation. Method aspects are also disclosed.

Electrodes and electrode arrays for generating electroporation inducing electrical fields

Abstract: Electrodes and electrode array apparatus and systems for in vivo delivery of electrical waveforms rendering therapeutic benefit to the patient by utilizing an electrode array having at least three individually addressable electrodes disposed so as to form a triangle in a plane intersecting the electrodes and an electrical signal generating device operatively connected to the electrodes for delivering electrical waveforms to said electrodes and generating electroporation-inducing electrical fields between the electrodes.

Method and apparatus for controlling and steering an electric field

Abstract: The electric field steering assembly is used to control the size and/or location of, and/or steer the position of, an electric field in a living creature. The assembly comprises a pulse generator or stimulator, at least one implanted lead coupled to the stimulator and having, at a distal end thereof, at least three spaced apart electrodes, and electrical circuitry for adjusting the current and/or voltage at each electrode. The electrical circuitry is programmed to: 1) electronically change the size and/or location of an electric field established between the electrodes by independently programming the current flowing through of one or more anode (+) electrode(s) from one or more cathode (-) electrode(s), thereby steering the size and location of the electric field to recruit only target certain tissue and exclude unwanted tissue; and, 2) automatically change the voltage amplitude at each anode in response to changes in electrode impedance in order to maintain a constant anodic current, thereby preserving, for the duration of the therapy, the original electric field found to be effective at implant time.

Ozone applications for disinfection, purification and deodorization

Abstract: A frame-type ozone generator (242) has a plurality of elongated electrodes (201, 202) deployed in substantially parallel, spaced relation to each other so as to form a substantially flat electrode array, and a flow generator (241) for generating a flow of oxygen containing gas through the electrode array in a direction substantially perpendicular to the electrode array. Each of the electrodes is formed from an electrically conductive core (211) covered with polyvinyl-difluoride (212). Preferably, each electrode array is arranged within a frame (206) of a given area. Also disclosed are an apparatus for treating a product with ozone-containing gas in which pressure-waves are used to enhance effectiveness of the ozone treatment, and a two-chamber batch method for implementing treatment of a product with possibly harmful gases such as ozone.

Buckled actuator with enhanced restoring force

Abstract: An electrostatic actuator device including a stationary support and a buckled, moveable support mounted to enter into contact with the stationary support. At least three electrodes are employed. The first is mounted on the moveable support and a second electrode is on the stationary support. A third electrode is mounted on one of the supports such that the electrodes are positioned to form two pairs of electrodes for electrostatic attraction therebetween. The electrodes are powered by a voltage supply to provide electrostatic attraction between pairs of electrodes and move them into electrostatic contact. The buckled electrode has a shape configured to transmit a restoring force to its portion in contact with stationary support upon application of voltage to another pair of electrodes. The preferred voltage provides a two phase driving force including a voltage to the first pair of electrode for a period of time in a cycle of operation and a voltage to the second pair of electrodes for a period of time in the same cycle, preferably with an interim period of time with no voltage applied after each application of voltage. Various arrangements of three or more electrodes are disclosed, as is the use of the actuator in a microvalve having at least one valve opening. A three way microvalve is also shown, as are two forms of two dimensional valve arrays.

Proposed specifications for a lumbar spinal cord electrode array for control of lower extremities in paraplegia

Abstract: The goal of the study was to provide specifications for a stimulating electrode array to be implanted in the lumbosacral spinal cord as part of a functional neuromuscular stimulation (FNS) system for control of lower extremity muscles in paralyzed individuals. Dual channel stimulation of the quadriceps activation pool in the feline ventral lumbo-sacral spinal cord was performed to measure electrode interactions and to explore the effect of various stimulation paradigms on muscle fatigue. There was no measurable overlap in the populations of motor neurons activated from 2 different electrodes for spacings /spl ges/1 mm with currents below 100 /spl mu/A. However, a statistically significant increase in the population of activated fibers due to current summation was observed when stimuli /spl ges/70 /spl mu/A. were simultaneously presented through pairs of electrodes within 3 mm of each other. Fatigue effects were studied with 3 paradigms: (1) stimuli were delivered through a single electrode, (2) stimuli were delivered through 2 electrodes with the stimulus to the second electrode presented during the refractory period of fibers stimulated by the first electrode, and (3) stimuli were interleaved between the 2 electrodes such that the stimulus to 1 electrode was presented midway between stimuli to the other electrode, and the rate of stimulation through a single electrode was half that used in the first 2 paradigms. During channel refractory and single channel stimulation did not differ from each other in the rate at which the muscle fatigued, in both cases the force decayed to 30% of its initial level within 2 min of the initiation of the stimulation regime, whereas the force with interleaved stimulation was still above the initial force at this time due to strong potentiation. Based on these results and on and activation pool dimensions obtained in an earlier study, preliminary specifications are presented for an electrode array to be implanted in the human spinal cord for functional neuromuscular stimulation.

Cochlear electrode array employing tantalum metal

Abstract: An implant device uses tantalum and tantalum pentoxide as a complete system for the conveyance of electrical stimulation pulses from stimulus-forming circuitry contained within an hermetic enclosure to the saline fluids of the cochlea (or other tissue to be stimulated). Internal coupling capacitors are not used, yet the danger of having DC current flow to the saline fluids is eliminated. A preferred embodiment is a cochlear prosthesis comprised of a multiplicity of electrode contacts made from sintered, anodized tantalum, connected via tantalum wire leads to tantalum feedthroughs into the hermetically sealed package containing the stimulus pulse-forming electronic circuitry. One or more counterelectrode contacts (for monopolar or bipolar configurations, respectively) consist of activated iridium, connected via platinum or other noble metal leads to noble metal feedthroughs. When powered-up, the stimulus generating circuit produces a steady polarizing potential of approximately half its maximum output voltage range, which potential is applied as a positive (anodizing) voltage to each tantalum electrode and associated lead and feedthrough, with respect to the activated iridium electrode(s), which act as the reference point for the circuit.

Radiation detector with shielding electrode

Abstract: A cross-strip radiation detector for detecting ionizing radiation with two non-parallel sets of signal strips formed on the same side of the detector. The detector includes a semiconductor having at least two sides. A bias electrode is formed on one side of the semiconductor. A signal electrode is formed on a side of the semiconductor and is used to detect the energy level of the ionizing radiation. A third electrode (the control electrode) is also formed on the semiconductor. The control electrode shares charges induced by the ionizing radiation with the signal electrode, shielding the signal electrode until the charge clouds are close to the signal electrode. The control electrode also alters the electric field within the semiconductor, such that the field guides the charge clouds toward the signal electrode when the clouds closely approach the signal electrode. Large detector arrays can be formed by butting such coplanar cross-strip detectors side-by-side without little dead area. High-voltage decoupling circuitry can be eliminated by maintaining the coplanar signal strips at substantially the same voltage.

Electrical impedance tomography method and electrode arrangement for use therein

Abstract: An electrode arrangement for an electrical impedance tomography system comprises a plurality of electrodes (S1-S16) in an array (22) mounted in a support medium (24, 26, 28, 30, 32) for supporting the electrodes adjacent a surface of a volume (12) the electrical conductivity distribution of which is to be measured, for example the thorax or another body part, a pipeline, the ground, and so on. The electrodes are disposed in two groups, the arrangement being such that, in use, one group (R1-R16) will be closer to the surface than the other group (S1-S16). In operation, each pair of electrodes will be stimulated in turn by applying a known current to them. For each stimulated pair, a resulting potential difference will be recorded at the pair of the remaining electrodes which, if stimulated, would produce an electric field with vectors of the electric field produced by the stimulated pair of electrodes.

Ozone and other reactive gas generator cell and system

Abstract: A reactive gas generator cell includes a high voltage assembly having a high voltage electrode plate and a low voltage assembly having a low voltage electrode plate. Each of the high and low voltage assemblies may include a cover plate and a channel plate. A welded metallic seal may join the high voltage assembly and the low voltage assembly to create a permanently sealed chamber between the assemblies. A refractory metal surface, which may be a tungsten surface, is disposed on at least one of the low voltage electrode plate and the high voltage electrode plate. A dielectric barrier is disposed between the high voltage electrode plate and the low voltage electrode plate. A discharge region for confining a reactive gas is defined, at least in part, by the refractory metal surface and a surface of the dielectric barrier. A spacer, which may be formed from a refractory material, may be positioned between the surface of the dielectric barrier and the refractory metal surface to define a predetermined gap.

Differential touch sensors and control circuit therefor

Abstract: A differential touch sensor apparatus for detecting the presence of an object such as a human appendage, the apparatus having a first electrode (16), a second electrode (18) positioned proximate to the first electrode, a differential circuit (Q1, Q2, 34, 48) connected to the first and second electrodes, and a pulse or other signal source (60) connected to provide electrical signals that generate an electric field between the first and second electrodes. Introduction of an object near the first electrode affects the electric field between the first and second electrodes, thereby affecting the voltage difference between them. A differential circuit provides an output signal responsive to the difference in voltage between the first and second electrodes. In an alternative embodiment, a strobe electrode (22) is provided proximate to both said first and second electrodes and the pulses or other signals are provided to the strobe electrode to induce an electric field between the strobe electrode and each of the first and second electrodes.

Effects of electrode configuration on psychophysical strength-duration functions for single biphasic electrical stimuli in cats

Abstract: The interface between electrode and neural target tissue is thought to influence certain characteristics of neural and behavioral responses to electrical stimulation of the auditory system. At present, the biophysical properties of this interface are not well understood. Here the effects of biphasic phase duration and electrode configuration on psychophysical threshold in response to electrical stimulation in cats are described. Five cats were trained to respond to acoustic stimuli using food as a reward in an operant reinforcement paradigm. After training, the animals were unilaterally deafened and implanted with a multicontact intracochlear electrode array. Thresholds for single presentations of biphasic current pulses were measured as a function of phase duration and electrode arrangement. Statistical analyses of the data indicated that strength-duration function slopes between 200 and 1600 microseconds/phase were significantly different for the different electrode configurations and, overall, were unrelated to the absolute level of the strength-duration function (i.e., were independent of absolute threshold). For all subjects, the slope of this function for intermediate pulse durations was dependent on electrode configuration and most shallow for radial-bipolar configurations (-3.4 dB/doubling), was steepest for monopolar arrangements (-5.9 dB/doubling), and was intermediate for longitudinal-bipolar pairings. (-4.4 dB/doubling). Slopes for both shorter and longer phase duration stimuli were not significantly different. The underlying mechanisms for these effects may include, or be a combination of altered electrical field patterns, integrated activity across multiple fibers, and stochastic behavior of individual auditory neurons to electrical stimulation.

Common electrode voltage driving circuit for a liquid crystal display

Abstract: A control circuit for providing a common electrode voltage for a liquid crystal display dynamically controls the voltage applied to the common electrode according to various factors that effect the capacitance across the liquid crystal layer. The common electrode control circuit dynamically adjusts the common electrode voltage according to the current maximum and minimum display voltages. In addition, the common electrode control circuit adjusts the common electrode voltage according to the gate-to-source parasitic capacitance, as well as temperature fluctuations. Thus, the control circuit compensates for the most significant factors which may cause the inadvertent accumulation of a charge across the liquid crystal layer.

Method and device for ion generation

Abstract: A method of high efficiency generation of ions of desired polarity which includes the steps of positioning a first electrode (5) at a predetermined spacing from a second electrode (7) having a closed shape configuration, applying to both electrodes a direct voltage of the same polarity, at the same time as applying the direct voltage, applying high voltage pulses to the first electrode only, thereby to cause ion generation in the vicinity of the first electrode and to set up a rapidly moving ion stream from the first to the second electrode along an electrical field therebetween, wherein the duration of the pulses is shorter than the time taken for the ion stream to reach the second electrode, and wherein ions in the ion stream have the same polarity as the second electrode, thereby to be repelled and concentrated as they flow through the second electrode. The method may also include the generation of a stream of ions, with reduced ozone content, which includes the additional step of applying a negative pressure gradient to the ion stream, thereby to deflect ozone generated by the corona discharge to a direction different from that of the flow of ions.

Nucleus double electrode array: a new approach for ossified cochleae.

Abstract: Introduction: The ossified cochlea is still a special surgical issue that requires a special surgical procedure. The current cochlear implants only have one electrode lead, which can be placed only partially in the drilled out basal turn. The small number of used active electrodes leads to worse performance as compared with patients with full insertion. Methods: To overcome this limitation, a special electrode was developed consisting of two arrays. One array with II active electrode rings is placed in the drilled out basal turn, the second array with 10 active electrodes in the opened second turn. The number of inserted electrodes can be significantly increased. The surgery is similar to that in nonossified cochleae. After the posterior tympanotomy, the bridge is removed and the incus is located. A cochleostomy is performed at the basal turn and the new-built tissue removed. A second cochleostomy is placed below the cochleariform process. In most cases, the second turn is not obliterated and the second electrode array can be fully inserted. Results: The surgical procedure was in all nine cases uneventful. Intraoperative stapedius reflex could be recorded with elevated thresholds. The wide variety of stimulation modes and sites allows an individual fitting to maximize the performance. All patients show a gap in the pitch scale between the apical and the basal array. The pitch variation is much smaller in the apical array. All patients have some benefit from the additional apical array and an improved performance. Conclusion: The nucleus double electrode array is an advanced treatment option for patients with ossified cochleae. The receiver/stimulator is a regular nucleus cochlear implant.

The advanced Combi 40+ cochlear implant.

Abstract: A 12-channel cochlear implant (Cl) for high-rate pulsatile stimulation strategies is presented. Symmetric biphasic current pulses can be generated up to a maximum pulse repetition rate of 18.18 kpulses/second. The stimulation pulse amplitude can be selected within 1.5 μA-1.5 mA. Data and power are transcutaneously transferred using a single radiofrequency (RF) channel. A fully digital data transfer format is employed at an overall data rate of 600 kBit/second. The implant contains a single mixed analog/digital CMOS-ASIC (Application Specific Integrated Description) for data synchronization and stimulus generation. Stimulation signals are applied via a monopolar intracochlear multichannel electrode. Output capacitors for each channel are employed for safety reasons. A self-calibrating back telemetry system is included for estimating the channel impedances and field distribution along the electrode array. Dimensions of the ceramic package of the implant are only 33.50 x 23.40 x 3.95 mm 3 .

Method for measuring particles in gas flow e.g. vehicle exhaust

Abstract: The method generates an electrical field between a hollow electrode (7,12), through which the gas flows, and an internal electrode (9,6) within the hollow electrode by the application of a constant d.c. voltage. The charging current required for maintaining a constant voltage between the electrodes is measured. The d.c. voltage required can be 2 to 3 kV and the charging current can be measured using a high value series resistance (8) in the current circuit as a shunt.

Device and method for real-time monitoring of an electrocardiogram during magnetic resonance imaging

Abstract: An electrode assembly for monitoring bioelectric signals includes a first electrode member and a second electrode member disposed around the first electrode member. When the electrode assembly is placed on a body of a person, a bioelectric signal is monitored by measuring the electrical potential between the first and second electrode members with the measurement device. The first and second electrode members may be single electrodes or two or more electrodes connected by conductors. Alternatively, the first and second electrodes can be formed from an array of electrodes by connecting the electrodes in a desired configuration either electrically or by use of a software algorithm.

Electrode and battery using the same

Abstract: An electrode in which an active material 11 or 7, an electron conducting material 12 or a current collector 5 or 6 has PTC characteristics is used as at least one of positive and negative electrodes 1 and 2.