Showing papers on "Electrode array published in 1991"

A silicon-based, three-dimensional neural interface: manufacturing processes for an intracortical electrode array

Abstract: A method is described for the manufacture of a three-dimensional electrode array geometry for chronic intracortical stimulation. This silicon based array consists of a 4.2*4.2*0.12 mm thick monocrystalline substrate, from which project 100 conductive, silicon needles sharpened to facilitate cortical penetration. Each needle is electrically isolated from the other needles, and is about 0.09 mm thick at its base and 1.5 mm long. The sharpened end of each needle is coated with platinum to facilitate charge transfer into neural tissue. The following manufacturing processes were used to create this array: thermomigration of 100 aluminum pads through an n-type silicon block, creating trails of highly conductive p/sup +/ silicon isolated from each other by opposing pn junctions; a combination of mechanical and chemical micromachining which creates individual penetrating needles of the p/sup +/ silicon trails; metal deposition to create active electrode areas and electrical contact pads; and array encapsulation with polyimide. >

Light modulation device with matrix addressing

Abstract: A light modulation device with matrix addressing including a matrix of cells. Each cell has two flaps fixed to a substrate by flexible attachments, a control electrode, a row electrode and a maintenance electrode. The flaps can adopt two stable positions through the application of suitable voltages to the row and maintenance electrodes. The flaps are activated by the application of a control voltage to the electrode at the same time as the voltage on the row electrode is returned to zero. The arrangement of the electrodes together with the existence of a maintenance electrode, which is common to all the flaps on the matrix, allows matrix addressing to be achieved.

Dual indifferent electrode pacemaker

Abstract: An endocardial lead having first and second spaced apart electrodes resides in a patient's heart The first electrode is a sensing electrode and the second electrode is a carrier signal driving electrode The lead has a conductor coupling a source of alternating current carrier signals of a predetermined frequency to the second electrode A third electrode is in electrical contact with body tissues A cardiac pacer apparatus includes a pacer can which functions as a fourth electrode and has a plastic top wherein the third electrode is located Said third electrode acts in cooperation with the first electrode to form a pair of sensing electrodes The sensing electrode pair is further coupled to a sense amplifier for receiving an amplifying modulated electrical signals developed across the sensing electrode pair A demodulator and filters circuit for demodulating the modulated carrier signal and recovering the modulating signal therefrom is connected to the output of the sense amplifier The modulating signal is proportional to instantaneous stroke volume of the patient's heart and the demodulator and filters circuit develops a control signal therefrom called a stroke volume signal The control signal is applied to the pulse generator so as to control the rate of stimulating pulses

Electrode assembly for nerve stimulation

Abstract: A nerve electrode array includes one or more Y-shaped carriers in which the three legs of the Y are curled about a common axis with the lower leg of the Y oppositely directed relative to the other two so that the legs will encircle a nerve substantially sharing the common axis, and a flexible electrode secured to the underside of at least one of the legs.

Total internal reflection electro-optic modulator

Abstract: The TIR modulator has an electrode array distributed across an area of the reflecting surface of the electro-optic material. The electrode array has interdigitated electrodes extending inward from a rectangular-shaped outer electrode conducting block and outward from a diamond-shaped inner electrode conducting block. A diamond-shaped area with no electrodes is preferably symmetrically within the inner electrode conducting block of the electrode array on the reflecting surface. The uniform voltage difference between the electrodes and the varying lengths of the electrodes creates a fringe electrical field in the electro-optical material and an optical phase grating to diffract the incident light on the reflecting surface. The zero order nondiffracted light becomes the output beam. The optical phase grating will control the incident beam's optical profile at the modulator (near field) and hence the imaged spot size at a focus at the image plane (far field). Alternatively, the TIR modulator can have a diamond-shaped interdigitated electrode pattern within a rectangular shaped area with no electrodes. Using Schlieren optics, the non-zero order diffracted beam becomes the output beam with a modulated optical beam profile. Alternatively, the TIR modulator can have uniform lengths to a rectangular interdigitated electrode pattern but varying voltage differences between electrodes.

Three-dimensional impedance imaging processes

Abstract: A method for obtaining sets of current patterns for three-dimensionally imaging the interior of a body having an internal resistivity using electrical impedance tomography comprises providing an array of electrodes arranged in a plurality of groups for an impedance imaging system. A linearly independent set of current patterns is also established for forming a basis for each group. A constant pattern is then adjoined to each basis for forming an augmented basis for each group. A tensor product is then taken of the augmented basis for forming a tensor product basis. Finally, the constant pattern from the tensor product basis is removed in order to establish a basis of current patterns for being applied to the array of electrodes.

Blood flow measuring apparatus

Abstract: The blood flow measuring apparatus comprises at least three electrodes, namely, a measuring electrode, reference electrode and an active neutral electrode, which are implanted at a predetermined tissue region. The signals of the measuring electrode and the reference electrode are delivered by input lines to a current and voltage isolated differential amplifier, the output of which is connected with a central unit controlling further instruments. What is important for the measuring accuracy of the blood flow measuring apparatus is an opposite feedback of external spurious fields which couple-in spurious potentials into the tissue and the shields of the input lines of the measuring electrode, reference electrode and neutral electrode. Further probes can be provided as an aid for the central unit.

Electrode array and use thereof

Abstract: An electrode array containing individual electrode segments having means to electrically bias each of the segments individually and to control the quantity of current supplied to each of the electrode segments individually; and use of the array.

Noise characteristics of stainless-steel surface electrodes.

Abstract: Bioelectric events measured with surface electrodes are subject to noise components which may be significant in comparison with low-level biological signals such as evoked neuroelectric potentials, and myoelectric potentials. In an effort to better understand noise arising from these electrodes, electrode and measurement system noise is modelled. The effect of electrode surface area on electrode impedance and noise is studied using circular stainless-steel electrodes of varying diameters. The main contributions of the work are the development of a model for stainless-steel electrode noise as a function of electrode area, and demonstrating that, for the band-width of interest to evoked neuroelectric and myoelectric signals (8–10 000 Hz), the primary noise components are thermal and amplifier current generated. The magnitudes of both of these depend on the electrode impedance magnitude. Electrode impedance is shown to be a power function of both electrode diameter and frequency, consistent with a capacitive electrode model.

Charge-coupled device and process of fabrication thereof

Abstract: A charge-coupled device has a multi-layer structure insulating layer is formed beneath a transfer electrode, floating electrodes and an electrode adjacent the floating electrodes so that pin hole phenomenon in a charge transfer section of the charge coupled device can be successfully prevented. On the other hand, a sole-layer structure insulating layer is formed beneath a gate electrode of a peripheral component so that a threshold voltage of the gate electrode of the peripheral component can be successfully controlled at a desired value.

Thin film transistor type liquid crystal display device

Abstract: PURPOSE: To prevent the electrostatic breakdown of a gate insulating film and a light leak near a drain electrode by providing a shield electrode among the drain electrode, the channel part of a TFT, and liquid crystal and applying nearly the same potential with a counter electrode. CONSTITUTION: A thin film transistor(TFT) substrate has a 1st insulating film 12, formed on a gate electrode 1, a 2nd insulating film 13 which is formed over the entire surface of the 1st insulating film except at the connection part between a source electrode 8 and a picture element electrode 4, and the shield electrode 11 which is formed over the entire surface of the 2nd insulating film except the connection part between the source electrode 8 and picture element electrode 4. Further, the substrate is equipped with a 3rd insulating film 14 which is formed over the entire surface of the shield electrode except at the connection part between the source electrode 8 and picture element electrode 4 and the picture element electrode 4 formed on the 3rd insulating film. In this case, a voltage inputted to the shield electrode 11 is nearly as high as a voltage inputted to the counter electrode of a counter electrode substrate. Then the shield electrode 11 and the electrode substrate which faces the TFT are electrically connected. COPYRIGHT: (C)1992,JPO&Japio

Liquid crystal display apparatus having a series combination of the storage capacitors

Abstract: An active matrix-type liquid crystal display apparatus, in which a pixel electrode and a common electrode line are not overlapped but coupled capacitively by a floating electrode, so that the pixel electrode and common electrode do not short-circuit, and a storage capacitance is formed by the series connection of a plurality of capacitors. An active matrix-type liquid crystal display apparatus, in which a pixel electrode and a gate electrode line at the succeeding or preceeding row are not overlapped but coupled capacitively by a floating electrode, so that the pixel electrode and gate electrode do not short-circuit, and a storage capacitance is formed by the series connection of a plurality of capacitors.

Electrostatic information recording medium and method of electrostatic information recording and reproducing

Abstract: PURPOSE:To improve picture quantities by successively forming an inorg. oxide layer and a photoconductive layer on an electrode. CONSTITUTION:On the electrode 2, there is formed an inorg. oxide layer 3, and further provided a photoconductive layer comprising a charge generating layer 4 and a charge transfer layer 5 thereon. For information recording, the medium is exposed for information to light during voltage is applied between the electrode 2 being disposed to be opposed to a counter electrode, or voltage is applied during the medium is exposed for information. After this, the surface of the photoconductive layer in the medium is subjected to corona discharge or surface charges are given according to the recorded information by applying voltage between the electrode 2 and the facing electrode. Then the surface charges are reproduced by reading means for surface potential, developing means with a toner, or a liquid crystal display device. In this case, an inorg. oxide layer 3 has an effect of blocking to prevent dark current due to charge injection from the electrode while voltage is applied.

Semiconductor device having a surge protecting element

Abstract: A MOSFET semiconductor device has a surge protecting element comprising a transistor element having a gate electrode, a source electrode, and a drain electrode. A Zener diode having a cathode electrode and an anode electrode is connected to the drain electrode of the transistor element. A lateral MOSFET element has a gate electrode and a drain electrode connected to the anode electrode of the Zener diode, a source electrode connected to the gate electrode of the transistor element, and a back gate electrode connected to the source electrode of the transistor element.

Apparatus for transmitting electrostatic spray gun voltage and current values to remote location

Abstract: An electrostatic spray gun having a self-contained power supply including a high voltage electrostatic voltage and current source, with circuits for monitoring the voltage and current and developing a frequency signal based on the monitored voltage and current, circuits for modulating the frequency signal with a radio frequency carrier and transmitting the modulated-carrier signal to a remote radio receiver, where the signals are demodulated and converted to a digital display representation of the monitored voltage and/or current.

Method and apparatus for compensation of double layer charging current in electrochemical cells

Abstract: A method and apparatus for compensating for charging current at a working electrode of an electrochemical cell. And a method for measuring faradaic current at the working electrode. Includes measuring the current at the working electrode while a time-varying potential difference is applied between the working electrode and a reference electrode. And while the applied potential difference is held constant for a short time and the working electrode current is again measured, where this current is the faradaic current. The faradaic current is then filtered from the total current to determine the charging current thereby compensating for double layer charging current in the cell.

Apparatus for plasma treatment

Abstract: The invention concerns an apparatus for the plasma treatment of substrates in a plasma discharge excited by a high frequency between two electrodes 3, 8 to which power is supplied by a high frequency source, where the first electrode is configured as a hollow electrode 3 and the second one as an electrode 8 holding a substrate 7 and situated upstream of the hollow chamber 10 of the first electrode which it also passes. The hollow electrode is enclosed by a dark space shield and has an edge pointing in direction of the second electrode and also has projection located between the edge. These projections are on the same potential as the second electrode. The radio frequency power is thus decoupled from the substrate bias voltage (selfbias) and the distance between the first and the second electrode can be changed.

Electrode array construction featuring current emitting electrodes and resistive sheet guard electrode for investigating formations along a borehole

Abstract: An electrode for use in the electrical investigation of a medium such as a borehole wall, comprises a sheet (32) of electrically resistive material having opposed first (34) and second (33) surfaces, one or more elongate electrical conductors (35,36) of low resistivity, an end face of each conductor abutting the first surface of the sheet (32) and means for sensing electric current passing through each conductor. In use, the second surface (33) of the sheet (32) is exposed to the medium to be investigated.

A method for evaluating the selectivity of electrodes implanted for nerve simulation

Abstract: The authors describe a method based on the compound action potential (CAP) that provides a precise measurement of the selectivity of an electrode array and yet is relatively simple to use. The method uses the refractory interaction of the CAPs elicited by a stimulus pulse pair, along with high-resolution recording of those potentials, to achieve measurements of the selectivity of stimulation down to the scale of a few axon diameters. The feasibility of this technique is demonstrated in sciatic nerves of frogs (Rana Catesbiana) acutely implanted with a sapphire electrode array. The high-resolution recording of the compound action potential provides a method for evaluating dense neurostimulation electrode arrays. The refractory interaction of these CAP responses provides a simple method for studying current spread and electrode interaction down to a spatial resolution of about 25 mu m, depending upon the particular nerve used. >

Apparatus for testing the insulation of an electrical conductor passing through an electrode

Abstract: Apparatus for testing the insulation on an insulated conductor wherein a high AC test voltage is applied to an electrode through which the insulated conductor is passing is presented and includes a testing station for applying the high AC test voltage potential to an electrode at a desired magnitude and frequency. Current induced in the electrode due to corona effects or arc current pulses due to a defect in the insulation are sensed by a current sensing transformed circuit to develop a insulation condition voltage signal. The insulation condition voltage signal together with a low voltage test signal proportional to the magnitude of the high AC test voltage potential are coupled to a remotely located controlled unit. A negative peak detector receives the low voltage potential to produce a bias voltage at the input to the fault detection circuit. The characteristics of the current sensing transformed circuit are such that current induced in the test electrode due to corona effects are shunted to ground reference voltage potential. Arc current pulses induced in the test electrode cause the insulation condition voltage signal to be produced at sufficient magnitude to exceed the bias voltage at the control unit and cause the fault detection circuit to provide a fault indication signal representation of a flaw or defect in the insulation of the portion of the insulated electrical conductor within the test electrode.

Semiconductor component with schottky junction for microwave amplification and fast logic circuits

Abstract: A semiconducting component with a Schottky junction with stacked electrodes has a lower electrode forming an emitter or source, a central electrode forming a base or grid and an upper electrode forming either a collector or a drain. Semiconductor material is between the upper electrode and the lower electrode. The central control electrode is in the form of several adjacent conducting fingers. An insulating material is in the region directly below the fingers between the control electrode and the lower electrode, thereby reducing parasitic capacitance between the control electrode and the lower electrode.

Electric spark machine

Abstract: An electrode for use in an electric spark machine has recording means integral therewith which stores an electrode information unique to the electrode. The electric spark machine reads the electrode information when the electrode is mounted thereon and stores it in a memory. The electric spark machine operates according to a machining program contained in the electrode information read from the memory while correcting misalignment of the electrode according to misalignment information contained in the electrode information.

Multichannel cochlear implant and electrically evoked auditory brainstem responses in a child with labyrinthitis ossificans

Abstract: Ossification of the cochlea following meningitis presents a surgical challenge. Electrode mapping, especially in the young child, is difficult given the uncertainty of electrode contact with viable neural elements. This paper reviews surgical technique and the use of auditory brainstem responses to map the electrodes. A 4-year-old child deafened by meningitis at age 20 months had bilateral cochlear ossification by computed tomography. At surgery, a canal wall-down mastoidectomy and closure of the ear canal were performed. A trough around the modiolus was drilled, and the electrode array was placed in it. Post-operatively, the patient gave aversive or no responses to electrode stimulation. To assess electrode function, auditory brainstem responses to individual electrode activation were obtained under general anesthesia. Functioning electrodes could thus be selected for mapping. The patient now responds well to sound.

Method and circuit for monitoring an ion- or redox-potential measuring electrode system

Abstract: A method and a circuit are provided for monitoring ion-sensitive or redox-potential-sensitive measuring electrode systems having at least two electrodes which are connected via a lead connection to an evaluation system, a voltage which varies with time being supplied as a test voltage to the measuring electrode system via the lead connection. In such a method and in such a circuit, the capacitance (CK) of the lead connection can seriously interfere with the measurement of the resistance (RG) of the electrode system. The test voltage is therefore fed into the lead connection via a series impedance (CV). An output voltage is taken off at the connection point (12) between series impedance and lead connection and a constant-phase or frequency-independent component of the total impedance formed by the measuring electrode system, lead connection and series impedance is determined from a relationship between output voltage and test voltage in the phase range and/or frequency range.

Passive microelectrode arrays for recording of neural signals: A simplified fabrication process

Abstract: A new process for the fabrication of microelectrode arrays is developed that is fully compatible with standard integrated circuit fabrication schedules. The process involves two innovations: the use of initially thin silicon substrates (50 μm), and the use of sputtered SiO2 as a plasma etching mask. The finished electrode array consists of a very thin silicon substrate (<20 μm) that provides a mechanically stable carrier for the electrodes. The electrode metal conductors are sandwiched between two layers of polyimide films that adhere firmly to the substrate. Small electrode interface and contact windows are made with lithographically limited minimum feature sizes. Dry plasma etching is employed both to open the windows and to thin the substrate. For the former, we have determined the appropriate etching conditions and thicknesses necessary for SiO2 to be a viable mask in this step. For the latter step, the electrode profile is first etched to the final desired substrate thickness from the front (with the same oxide as the mask), and the wafer is then turned over and fully etched until the electrodes separate. Using initially thin wafers simplifies considerably this final etch.

Method and apparatus for reducing IR error in cathodic protection measurements

Abstract: An apparatus for measuring cathodic protection voltage levels on a concealed conductive structure, includes a probe having a standard half cell reference electrode, a working electrode and an auxiliary electrode mounted in a fixed spacial relationship to each other, wherein the reference electrode, working electrode and auxiliary electrode are each in contact with an electrolytic solution. A voltage measuring device is provided for receiving a voltage from said reference electrode. The voltage measuring device provides an indication of the voltage difference between the reference electrode and a common reference point. A switch is included for connecting and disconnecting the working electrode with the common reference point. A voltage detecting circuit detects voltage between the concealed conductive structure, which is subject to a cathodic protection voltage, and the common reference point. A bias voltage is applied to the auxiliary electrode in response to the voltage level between the concealed conductive structure and the common reference point. The voltage measured by the voltage measuring device provides an indication of the adequacy of cathodic protection voltage levels on the concealed conductive structure.

Forming planar ITO gate electrode array structures

Abstract: A method of forming a planar ITO gate electrode structure with sub-micron spacing includes forming L-shaped nitride spacer portions.

Single wafer plasma etching system

Abstract: The present invention provides an apparatus and a method to improve the single wafer RF plasma etching. A plasma etching apparatus including an etching chamber having a first electrode and a second electrode disposed in the etching chamber with a wafer to be etched disposed on the first electrode. The etching chamber having a chamber reference voltage and the first and the second electrodes being electrically isolated from the etching chamber. The plasma etching system also has an RF generator producing a radio frequency input voltage and a voltage and phase controller electrically connected to the RF generator. The voltage and phase controller is further connected to the first electrode and the second electrode to generate in the first electrode and the second electrode two corresponding voltages substantially equal in magnitude but of opposite signs relative to said chamber reference voltage and further that the first electrode always has a lower voltage than the second electrode such that the ionized particles move to the wafer disposed on the first electrode through the entire RF cycle.

A Method for Measuring Ohmic Resistance of Solution Layers at Gas‐Evolving Electrodes

Abstract: In this paper we present what is the combination of those two methods and what is convenient to systematically determine the electrode surface resistance. Such a method consists of measuring of IR component by interruption of the current as a function of the distance of the reference electrode to the working electrode