259 results about "Contact impedance" patented technology

An electrosurgical generator is disclosed. The generator includes a radio frequency output stage configured to generate a frequency waveform to an active electrode of an electrosurgical instrument when the active electrode is disposed in a fluid medium. The generator also includes a sensor circuit configured to measure tissue impedance and a controller configured to increase power of the radio frequency waveform to a predetermined electrical arcing level in response to the tissue impedance being within an open circuit impedance range and tissue contact impedance range. The controller is further configured to lower the power of the radio frequency waveform to a lower level when the tissue impedance is outside the open circuit impedance range and the tissue contact impedance range.

A multiple RF return pad contact detection system is provided which is adaptive to different physiological characteristics of patients without being susceptible to electrosurgical current interference (e.g., interference or measurement interaction between components of the detection system). The detection system can measure or sense the contact resistance or impedance between the patient and pairs of RF return pads or return electrodes where multiple pairs of RF return pads are utilized due to the high current frequently needed during electrosurgery while eliminating or minimizing the risk of measurement interaction between the RF return pad pairs. The system allows for the independent and simultaneous measurement of the pad contact impedance for each pair of RF return pads. If the impedance of any pad pair is above a predetermined limit, the system turns off or reduces the electrosurgical output of the electrosurgical generator to prevent excess heating. The system eliminates or minimizes interference or measurement interaction between the pad pairs by providing a different signal source frequency for each pad contact pair, but a frequency which matches an associated series resonant network frequency. The current that flows in the series resonant network is a direct reflection or function of the pad impedance of the corresponding pad pair.

A multiple RF return pad contact detection system is provided which is adaptive to different physiological characteristics of patients without being susceptible to electrosurgical current interference (e.g., interference or measurement interaction between components of the detection system). The detection system can measure or sense the contact resistance or impedance between the patient and pairs of RF return pads or return electrodes where multiple pairs of RF return pads are utilized due to the high current frequently needed during electrosurgery while eliminating or minimizing the risk of measurement interaction between the RF return pad pairs. The system allows for the independent and simultaneous measurement of the pad contact impedance for each pair of RF return pads. If the impedance of any pad pair is above a predetermined limit, the system turns off or reduces the electrosurgical output of the electrosurgical generator to prevent excess heating. The system eliminates or minimizes interference or measurement interaction between the pad pairs by providing a different signal source frequency for each pad contact pair, but a frequency which matches an associated series resonant network frequency. The current that flows in the series resonant network is a direct reflection or function of the pad impedance of the corresponding pad pair.

The present invention provides a non-contact impedance sensor which is mounted on measuring region, the radial section structure of the sensor comprises of four layers, metal tube layer, insulation material layer, electrode array layer and insulation ring layer from outside to inside in turn. At least two electrodes are distributed in one circle on the insulation ring layer whose thickness is less than 1% of external diameter, and electric field intensity between electrode array and metal tube layer is less than breakdown strength of insulation layer. The electrode array is separated with measuring region by insulation ring layer. Two image reconstruction algorithms to realize electrical impedance tomography based on the said sensor are also provided. The present invention provides analytical medel, corresponding sensitivity distribution expression and two rapid imaging methods, the sensor can measuring synchronous same-positional dual-mode impedance, advance mutual fusion of real parts and imaginary part information of impedance distribution, predigest the design and implement of software and hardware of dual-mode measuring system.

The invention provides a flexible skin surface dry electrode and a preparation method thereof. The flexible skin surface dry electrode comprises a flexible conducting substrate and multiple microneedle bodies forming a microneedle array, wherein each microneedle body is of a taper shape and comprises a root part and a front end, the root parts of the multiple microneedle bodies are fixed on one surface of the flexible conducting substrate, and the front ends of the microneedle bodies are higher than the surface of the flexible conducting substrate. According to the invention, the substrate material of an original dry electrode is changed from a rigid material into a flexible material; since the flexible substrate can be tightly attached to the skin, the microneedles on the dry electrode overcome the influence of keratoderma, the electrical contact characteristic of the electrode and the skin is improved and the contact impedance is reduced; when an external force acts on the dry electrode, the flexible substrate can generate elastic deformation, thus the breaking of the microneedles is effectively avoided and the use safety is improved; and the substrate material of the dry electrode with the flexible substrate is elastic, thus the wearing uncomfortableness is alleviated.

A signal-to-noise ratio and measurement precision is increased in electrode units disposed on the left and right sides of a steering wheel. A plurality of electrode units is disposed in the left and right handholds of a steering wheel. The contact impedances of all the electrode units are measured. A pair of left and right electrode units to be used to measure an electrocardiographic signal is designated from among the electrode units whose measured contact impedances are less than or equal to a first threshold. The results of measurement of an electrocardiographic signal by the designated electrode units are added in order to minimize noise. An electrode unit with high contact impedance is used to measure induction noise and remove the induction noise component from the electrocardiographic signal measurement result.

The invention discloses a measuring device and method for contact impedance between electrodes and skin. The device comprises a processor, a current source, a voltage measuring circuit, a displayer and an alarm. The current source, the voltage measuring circuit, the displayer and the alarm all interact with the processor. The current source and the voltage measuring circuit are connected with an electrode system formed by multiple electrodes and tightly attached to the surface of the skin of a user through a multi-way switch. Excitation currents are injected into the different electrodes, measuring electrodes are selected, and therefore the contact status between all the electrodes and the skin can be obtained in real time. The magnitude of the contact impedance is obtained through calculation through a boundary voltage value and an excitation value, and the contact status of the electrodes is judged according to an averaging method and a threshold value method. According to the method, it is proved through a simulation experiment and a calibration board experiment that the method is superior to an existing measuring technology on the aspects of measuring speed and measuring precision, the requirements of displaying the contact status of all the electrodes in real time in the electrical impedance detection process are met, and the data quality based on an electrical impedance measuring system is further improved.

The resolution and contrast of impedance measurements and scans are improved by using a non-contact impedance probe comprising an inner conductor configured to bear a measurement signal and an outer conductor configured to bear a shielding signal. The measurement signal and shielding signal are selected to increase the directionality of the flux emitted from the impedance probe. In one embodiment, the measurement signal and the shielding signal are phase locked signals. A sample may be placed in a basin having a conductive surface that receives the flux emitted from the impedance probe. By filling the basin with a conductive solution, direct contact between the probe and the sample may be avoided along with the associated variability in contact resistance. The small highly-directional flux emitting area achievable with the present invention enables high resolution high contrast non-contact scanning of biological and non-biological materials.

The embodiment of the invention discloses a socket conductor and a socket system. The socket conductor comprises a socket body, an inclined oval two-way spiral spring contact finger, a single-line spring and an offset-line spring, wherein the inclined oval two-way spiral spring contact finger is spirally surrounded into a unit ring by a spring wire along an inclined oval track, the unit ring is in two-way spiral wounding along the axial line, the inclined oval two-way spiral spring contact finger is sheathed on the single-line spring and is embedded into a groove of the offset-line spring in an adapting way, the inner circumference of the spring contact finger forms an insertion hole, and the offset-line spring is arranged in a socket body hole. When a plug is inserted into the socket conductor, the inner wall of the inclined oval two-way spiral spring contact finger is extruded by the plug to deform, the inclined oval deformation of the unit ring is gradually generated in the spiral axial direction in the insertion process, the contact points and the contact paths of the plug and the socket conductor are increased, on the basis, the stress deformation degree becomes lenitive, the contact is more reliable, and the contact impedance is more stable.

The invention discloses a brain electrical impedance detection circuit, comprising a drive unit and a detecting unit. The drive unit is composed of a constant electrical source and a grounded resistor; the electricity of the constant electrical source runs through the leads and the grounded resistor, forming an electric loop; the detecting unit comprises a band-pass filter circuit, a multi-way switch, a first amplifying circuit, a demodulation circuit and a controller; wherein the band-pass filter circuit filters the brain electrical signals, the controller controls the multi-way switch to switch the brain electrical signals outputted by the filter circuit to the first amplifying circuit in turn according to set time order; the filtered brain electrical signals are outputted to the demodulation circuit after being processed by the first amplifying circuit and the demodulation circuit outputs brain electrical impedance value after demodulation. The invention can detect the contact resistances of a plurality of electrodes while conducting brain electrical detection. The invention provides forceful and timely basis for wiping off electrocortical potential distance according to connection state of the leads and the scalp in the detection.

An apparatus and method that determines a quality of a connection of an electrode to a patient is provided. The apparatus includes at least three electrodes selectively connected to a patient for sensing an electrophysiological signal representing a patient parameter. A current source is connected to each of the at least three electrodes, the current source able to apply both a positive current and a negative current. A control processor is connected to the current source and the at least three electrodes. The control processor identifies a number of unique electrode pairs of the at least three electrodes and controls the current source to simultaneously apply a positive current to one electrode and a negative current to an other electrode of each identified electrode pair to determine a connection quality for at least one of the at least three electrodes.

The invention discloses a safety-type large-power, large-current and high-voltage-resistant composite electrical connector, and the connector comprises a conductive connection module and insulating protection bushings, wherein the conductive connection module comprises a conductive connection male head, a conductive connection female head, and a locking bolt. The conductive connection male head and the conductive connection female head are in holding-on connection, and are fastened through the locking bolt. The two insulating protection bushings are arranged symmetrically, and respectively sleeve the tail parts of the male head and the female head. When the bolt of the connector is screwed up, the inclined surfaces of two sides of a clamping head are pressed to slide oppositely, and plastic deformation is aroused. Not only are the upper and lower surfaces pressed, but also the inner end face and the outer end face are pressed. A rough line in a specific reference map represents a conductive junction surface, and the conductive junction surface enables the surface contact to be more complete, thereby reducing the contact impedance, and improving the current conducting capability.

A galvanic resistivity tool with one or more measurement electrodes and guard electrodes, and one or more shielding electrodes. The potential difference between the measurement electrodes and the guard electrodes is controlled to minimize current flow between the measurement electrodes and the shielding electrodes. This provides improved focusing and avoids effects of contact impedance.

The invention relates to a graphene-PDMS flexible substrate electrocardiogram dry electrode based on a tip array structure and a preparation method thereof. a graphene-PDMS flexible substrate is designed on a top surface thereof, a paraxylene film is deposited on tip array structure, metal seed layer is sputtered on paraxylene film, a metal lalyer is sputtered on the metal seed layer. The bottom surface of the graphene-PDMS flexible conductive substrate is coated with a conductive silver paste layer. The process of the invention is simple, the cost is low, and the production of the mould is favorable for batch production. The materials such as conductive silver colloid, PDMS, graphene, paraxylene film and sputtered titanium and gold have good biological compatibility, and can effectively inhibit bacteria and reduce skin irritation. The tip array structure designed by the invention has a larger contact area, and can pass through the stratum corneum by directly contacting with the skin,so that contact impedance of the skin-electrode can be effectively reduced, thus obtaining a stable ECG signal.

The invention relates to a wireless, portable and wearable electrocardiogram detector capable of restraining motion interference. The wireless, portable and wearable electrocardiogram detector comprises a simulation processing module, a control module and a power supply module; the power supply module supplies power to the simulation processing module and the control module; the simulation processing module comprises an electrocardiogram detection channel, a skin electrode contact impedance detection channel and a human body voltage and current driving channel, and the electrocardiogram detection channel, the skin electrode contact impedance detection channel and the human body voltage and current driving channel are used for collecting electrocardiogram signals containing the motion interference, collecting skin electrode contact impedance signals caused by motion and providing human body common-mode voltage and alternating voltage current respectively; the control module comprises an analog-digital converter, a microcontroller and a digital signal processor; the input end of the digital signal processor receives digital signals obtained from the electrocardiogram signals containing the motion interference; the reference end of the digital signal processor receives digital signals obtained from the skin electrode contact impedance signals caused by the motion; and the electrocardiogram signals without the motion interference are obtained according to the adaptive algorithm. By means of the wireless, portable and wearable electrocardiogram detector, the good and reliable electrocardiogram signals can be obtained in the motion state.

An apparatus and method that determines a quality of a connection of an electrode to a patient is provided. The apparatus includes at least three electrodes selectively connected to a patient for sensing an electro-physiological signal representing a patient parameter. A current source is connected to each of the at least three electrodes, the current source able to apply both a positive current and a negative current. A control processor is connected to the current source and the at least three electrodes. The control processor identifies a number of unique electrode pairs of the at least three electrodes and controls the current source to simultaneously apply a positive current to one electrode and a negative current to an other electrode of each identified electrode pair to determine a connection quality for at least one of the at least three electrodes.

The invention relates to a conductive paste composition, preparation of electrode using the same and solar cell comprising the same. The conductive paste composition comprises a mixing powder comprising a micro conductive metal powder with average grain size of below 0.5Mum and a conductive metal powder with average grain size of between 0.5 to 10Mum, an inorganic viscosity resin and an organic medium. The conductive paste composition can have high sintered density during preparing the electrode material and less sintering shrinkage, thereby providing lower electrode line impedance and contact impedance and increased efficiency of the solar cell.

The invention relates to a shield sleeve (1) for producing an electrical connection between a cable shield and a metal housing portion (4') of a connection element. The invention further relates to a shielding end element (70) comprising such a shield sleeve (1) and a crimp sleeve (2) which is constructed so as to be able to be fitted over the shield sleeve (1). Shield sleeves (1) are known from the prior art. Shield sleeves having a cylindrical sleeve member (13) in which a circular ring is arranged at one end, said ring extending perpendicularly relative to the cylinder axis and consequently perpendicularly relative to the direction of the cable, are widespread. With such shield sleeves (1), the contact force and consequently the contact resistance are highly dependent on the connection and the force between the housing portions of the connection element. The contact resistance is further relatively high. An object of the present invention is to provide a shield sleeve (1) which ensures secure and consistent contact resistance which is substantially independent of the forces between the housing portions (4' 4'') of the connection element. The object is achieved according to the invention by a shield sleeve (1) which comprises a rotationally symmetrical sleeve member (13), at one end (D) of which there is arranged at least one radially protruding contact flap (11) which can be resiliently redirected in a radial direction (R), the contact flap (11) having at least one contact location (12) which protrudes in a radial direction with respect to the sleeve member (13). A shielding end element (70) according to the invention comprises a shield sleeve (1) according to the invention and a crimp sleeve (2) which is constructed so as to be able to be fitted over the shield sleeve (1).

A MOSFET device and fabrication method are disclosed. The MOSFET has a drain in chip plane with an epitaxial layer overlay atop. The MOSFET further comprises: a Kelvin-contact body and an embedded Kelvin-contact source; a trench gate extending into the epitaxial layer; a lower contact trench extending through the Kelvin-contact source and at least part of the Kelvin-contact body defining respectively a vertical source-contact surface and a vertical body-contact surface; a patterned dielectric layer atop the Kelvin-contact source and the trench gate; a patterned top metal layer. As a result: a planar ledge is formed atop the Kelvin-contact source; the MOSFET device exhibits a lowered body Kelvin contact impedance and, owing to the presence of the planar ledge, a source Kelvin contact impedance that is lower than an otherwise MOSFET device without the planar ledge; and an integral parallel Schottky diode is also formed.

The invention discloses a flexible electrode which comprises an electrode inner layer, an electrode outer layer and a conductive contact. By mixing molten metal and fusion elastomer, the electrode inner layer is formed by curing; the electrode outer layer has the conductivity and covers the bottom of the electrode inner layer, and the electrode outer layer is composed of a solid conductive material and an elastomer, the solid conductive material is evenly distributed in the elastomer; one end of a conductive connector stretches into the bottom of the electrode inner layer, and the other end ofthe conductive connector is connected with an external element to form electric connection. The flexible electrode has the high conductivity and high flexibility, has the advantages of being safe, reliable, stable in performance and capable of being used for the myoelectricity sensor and the like, when the electrode is in use, the electrode outer layer can be attached to the skin, the contact resistance between the electrode and the skin is small, myoelectric signals with the high signal to noise ratio is collected, and the huge potential application value in rehabilitation medical engineering and motion monitoring is achieved.

The invention discloses a human body composition analyzer. The human body composition analyzer comprises a detecting electrode unit, a control device and an analysis device. The detection electrode unit is connected with the control device which is connected with the analysis device. The detection electrode unit makes contact with a human body and is used for outputting measurement current and collecting a detection signal, wherein the detection electrode unit can output measurement current at multiple frequencies. The control device is used for controlling the frequencies of the measurement current and receiving the detection signal. The control device sends the detection signal to the analysis device. The analysis device is used for analyzing the human body composition on the basis of the detection signal. The human body composition analyzer performs biological impedance measurement in a multi-frequency mode and can cover all frequencies needed for human extracellular composition and human intercellular composition, a measurement result can be more accurate, the advantages that electrode end contact impedance is eliminated, long-cable impedance is eliminated, and body weight measurement accuracy is improved are achieved, and more accurate living body composition data can be acquired.

The invention relates to a current-limiting switch circuit and a switching power supply device. The current-limiting switch circuit comprises a voltage control module, a switch module, and a compensation module, wherein the first input end of the voltage control module receives an associated voltage; the second input end of the voltage control module receives a reference voltage; the voltage control module generates a charging control signal according to the associated voltage and the reference voltage; the charging control signal is output through the output end of the voltage control module;the input end of the switch module receives input current of the input voltage end, and determines whether to charge the output voltage end or not according to the charging control signal; the compensation module is adapted to generate a compensation current according to the input current of the input voltage end; the compensation current is used to provide compensation to the output voltage end.The technical scheme can effectively compensate voltage drop caused by line loss, cable impedance, contact impedance and the like.

A method of fabricating a semiconductor device with a composite contact is provided. The fabrication includes forming the composite contact to a semiconductor layer in a semiconductor structure. The composite contact is formed by forming a DC conducting electrode attached to a semiconductor layer in a semiconductor structure and forming a capacitive electrode that is partially over the DC conducting electrode and extends beyond the DC conducting electrode. The composite contact provides a combined resistive-capacitive coupling to the semiconductor layer. As a result, a contact impedance is reduced when the corresponding semiconductor device is operated at high frequencies.

The invention discloses an organic light emitting display panel having a display region and a peripheral region. The organic light emitting display panel includes a substrate, multiple sub pixel regions and a cathode arranged on the display region, an auxiliary cathode and multiple contact holes, wherein an input end of the cathode extends to the peripheral region, the cathode and the auxiliary cathode are electrically connected through the contact holes, each sub pixel region corresponds to at least one contact hole, the further the contact hole is from the input end of the cathode, the larger the size of the contact hole, and at least one of the contact holes is arranged in each of the sub pixel regions. The display panel is advantaged in that through designing the contact holes with therelatively large size, contact impedance of the auxiliary cathode and the cathode can be reduced, the cathode voltage can be better reduced, the actual cathode voltage is made to be closer to the input cathode voltage, and uniformity of display brightness is improved.