Showing papers on "Electrode array published in 1998"

Noninvasive devices, methods, and systems for shrinking of tissues

Abstract: The invention provides improved devices, methods, and systems for shrinking of collagenated tissues, particularly for treating urinary incontinence in a noninvasive manner by directing energy to a patient's own support tissues. This energy heats fascia and other collagenated support tissues, causing them to contract. The energy can be applied intermittently, often between a pair of large plate electrodes having cooled flat electrode surfaces, the electrodes optionally being supported by a clamp structure. Such cooled plate electrodes are capable of directing electrical energy through an intermediate tissue and into fascia while the cooled electrode surface prevents injury to the intermediate tissue, particularly where the electrode surfaces are cooled before, during, and after an intermittent heating cycle. Ideally, the plate electrode comprises an electrode array including discrete electrode surface segments so that the current flux can be varied to selectively target the fascia. Alternatively, chilled “liquid electrodes” may direct current through a selected portion of the bladder (or other body cavity) while also cooling the bladder wall, an insulating gas can prevent heating of an alternative bladder portion and the adjacent tissues, and/or ultrasound transducers direct energy through an intermediate tissue and into fascia with little or no injury to the intermediate tissue. Cooled electrodes may be used to chill an intermediate engaged tissue so as to cause the maximum temperature difference between the target tissue and the intermediate tissue prior to initiating RF heating. This allows the dimensions of tissue reaching the treatment temperature to be controlled and/or minimized, the dimensions of protected intermediate tissue to be maximized, and the like.

Visual prosthesis and method of using same

Abstract: A visual prosthesis comprises a camera for perceiving a visual image and generating a visual signal output, retinal tissue stimulation circuitry adapted to be operatively attached to the user's retina, and wireless communication circuitry for transmitting the visual signal output to the retinal tissue stimulation circuitry within the eye. To generate the visual signal output the camera converts a visual image to electrical impulses which are sampled to selecting an image at a given point in time. The sampled image signal is then encoded to allow a pixelized display of it. This signal then is used to modulate a radio frequency carrier signal. A tuned coil pair having a primary and a secondary coil are used to transmit and receive the RF modulated visual signal which is then demodulated within the eye. The retinal stimulation circuitry includes a decoder for decoding the visual signal output into a plurality of individual stimulation control signals which are used by current generation circuitry to generate stimulation current signals to be used by an electrode array having a plurality of electrodes forming a matrix. The intraocular components are powered from energy extracted from the transmitted visual signal. The electrode array is attached to the retina via tacks, magnets, or adhesive.

Method for electrosurgical cutting and ablation

Abstract: An electrosurgical probe (10) comprises a shaft (13) having an electrode array (58) at its distal end and a connector (19) at its proximal end for coupling the electrode array to a high frequency power supply (28). The shaft includes a return electrode (56) recessed from its distal end and enclosed within an insulating jacket (18). The return electrode defines an inner passage (83) electrically connected to both the return electrode and the electrode array for passage of an electrically conducting liquid (50). By applying high frequency voltage to the electrode array and the return electrode, the electrically conducting liquid generates a current flow path between the return electrode and the electrode array so that target tissue may be cut or ablated. The probe is particularly useful in dry environments, such as the mouth or abdominal cavity, because the electrically conducting liquid provides the necessary return current path between the active and return electrodes.

Coordinate input device and display-integrated type coordinate input device capable of directly detecting electrostatic coupling capacitance with high accuracy

Abstract: In a coordinate detection period, a first electrode drive circuit sequentially selects source electrodes Sn of the TFT LCD panel to connect the same to an x-signal current amplifying circuit, and to apply an AC voltage to the non-selected electrodes. The x-signal current amplifying circuit detects a detection current flowing through the selected electrode, the magnitude of which corresponds to a distance to a finger (or a conductor pen), to obtain an x-coordinate detection voltage. A second electrode drive circuit and a y-signal current amplifying circuit operate in similar fashion to obtain a y-coordinate detection voltage. A coordinate detection circuit then obtains the x- and y-coordinate values of the designated position based on the x-coordinate detection voltage and the y-coordinate detection voltage, thus enabling pointing by a codeless pen and a finger.

Method for treating tumors near the surface of an organ

Abstract: A system for treating a target region in tissue beneath a tissue surface comprises a probe for deploying an electrode array within the tissue and a surface electrode for engaging the tissue surface above the treatment site. Preferably, surface electrode includes a plurality of tissue-penetrating elements which advance into the tissue, and the surface electrode is removably attachable to the probe. The tissue may be treated in a monopolar fashion where the electrode array and surface electrode are attached to a common pole on an electrode surgical power supply and powered simultaneously or successively, or in a bipolar fashion where the electrode array and surface electrode are attached to opposite poles of the power supply. The systems are particularly useful for treating tumors and other tissue treatment regions which lie near the surface.

Computerized EMG diagnostic system

Abstract: A generally flat, rectangular rubber pad support discrete, non-invasive electrodes in a 7 by 9 array and a ground electrode to collect surface electromyographic (EMG) signals from an underlying muscle group of a patient. Electronic apparatus conditions the EMG signals and is programmed to survey the electrode array simultaneously to provide a description of the activity of individual muscles in the muscle group at that point in time. The description is displayed on a video monitor or the like, juxtaposed over a display of normal muscle anatomy, with differences being emphasized by color enhancement. The electrode pad is particularly suited for the lower back muscle groups and may be retained in position by a lumbar support belt having a pad molded to the contours of the human spine.

Systems and methods for electrosurgical tissue treatment in conductive fluid

Abstract: An electrosurgical probe ( 10 ) comprises a shaft ( 13 ) having an electrode array ( 58 ) at its distal end and a connector ( 19 ) at its proximal end for coupling the electrode array to a high frequency power supply ( 28 ). The shaft includes a return electrode ( 56 ) recessed from its distal end and enclosed within an insulating jacket ( 18 ). The return electrode defines an inner passage ( 83 ) electrically connected to both the return electrode and the electrode array for passage of an electrically conducting liquid ( 50 ). By applying high frequency voltage to the electrode array and the return electrode, the electrically conducting liquid generates a current flow path between the return electrode and the electrode array so that target tissue may be cut or ablated. The probe is particularly useful in dry environments, such as the mouth or abdominal cavity, because the electrically conducting liquid provides the necessary return current path between the active and return electrodes.

Electrode with improved signal to noise ratio

Abstract: An electrode assembly for sensing an electrochemical signal diffused from a source to a working electrode which is comprised of a plurality of substantially separated working electrode surfaces is disclosed. The electrode of the invention is comprised of (1) a working electrode made up of a plurality of working electrode surfaces or components, and (2) an electrically insulating gap defined by adjacent edges of (1) insulating the working electrode surfaces or components from each other. The working electrode components are configured to receive electrochemical signal from two or preferably three dimensions simultaneously. The working electrode components configured over the same surface as a single electrode provide (1) an improved signal to noise ratio as compared to a single electrode by reducing noise, and (2) provided an overall enhanced signal after sensing for a given period of time.

Modification of parallel activity elicited by propagating bursts in developing networks of rat cortical neurones

Abstract: Networks of cultured cortical neurones exhibit regular, synchronized, propagating bursts which are synaptically mediated, and which are hypothesized to play a part in activity-dependent formation of connections during development in vivo. The relationship between the strength of synaptic connections and the characteristics of synchronized propagating bursting, however, is unclear. Modification of synchronized activity in cortical cultures in response to electrical stimulation was examined using multisite electrode array recording. By measuring the response of the network to weak, localized, test stimulation (TS), we observed a potentiation of activity following a relatively stronger inducing stimulation (IS). This potentiation was evident as an increased probability of eliciting bursts by TS, an increased frequency of spontaneous bursts and number of spikes per burst, and increased speed of burst propagation, and it lasted for at least 20 min. Changing the parameters of IS revealed that high frequency tetanic stimulation is not necessary to induce potentiation, while it is essential for IS to produce a regeneratively propagating burst. The results provide a direct demonstration of modification of both the spatial and temporal characteristics of synchronized network activity, and suggest an important physiological role for propagating synchronized bursting, as a mechanism for inducing plastic modifications in the developing cortex.

Methods and apparatus for imaging earth formation with a current source, a current drain, and a matrix of voltage electrodes therebetween

Abstract: The borehole imaging apparatus of the present invention includes a tool having an array of voltage electrode buttons mounted on a non-conductive pad. A current source and a current return are preferably located on the non-conductive pads at opposite ends thereof. The locations of the current source and return are designed to force a current to flow in the formation parallel to the pad face and non-parallel to the formation boundary layers. According to a method of the invention, the voltage difference between a pair of buttons in the array is proportional to the resistivity of the formation bed adjacent to the buttons. The ratio of voltage differences between two nearby pairs of electrode buttons provides a quantitative measurement of the ratio of shallow resistivity. The resolution of the image produced by the new tool is determined only by the spacing of the buttons. The tool according to the invention produces much better images than the prior art tools when used in OBM wells. In order to assure that current flow is not tangential to bed boundaries, it is preferred that the non-conductive pad be provided with a pair of orthogonal current sources and current returns. According to a presently preferred embodiment of the invention, the voltage electrodes are arranged in a matrix having offset rows and measurements are made for adjacent electrodes in two dimensions.

Single-ended to differential converter

Abstract: A single-ended to differential converter (400, 500) has an input terminal (418, 518) which is adapted to be coupled to an inductance (412, 512). A first transistor (402, 502) which terminates an input signal received at the input terminal according to its transconductance has a first current electrode coupled to the input terminal. A second current electrode of the first transistor (402, 502) outputs one current of a differential output current. A second transistor (404, 504) has a control electrode coupled to the input terminal, a first current electrode coupled to a signal ground terminal, and a second current electrode for providing another current of the differential output current. Bias circuits bias the control electrodes of the first (402, 502) and second (404, 504) transistors to maintain the same DC currents through their current electrodes. The single-ended to differential converter (400, 500) reflects the noise produced by the first transistor (402, 502) in the second transistor (404, 504), and this common-mode noise can be rejected in a subsequent stage.

Cochlear electrode with modiolar-hugging system including a flexible positioner

Abstract: An electrode system includes: (a) an electrode array (10), made in a straight or curved shape, but made on a flexible carrier so that it can easily bend within a curved body cavity, such as the scala tympani duct of the human cochlea; and (b) a flexible positioner (20), typically molded in a curved shape from a silicone polymer so as to make it easy to slide into the body cavity. Some embodiments may further include an electrode guiding insert (30). The flexible positioner (20, 20') fills space within the scala tympani so as to force an electrode array against a modiolar wall. One embodiment of the positioner (20') includes a channel (27) through which a guiding wire stylet may be removably inserted. A platinum marker (29) may be embedded within the distal tip of the positioner (20') to facilitate viewing the location of the positioner on an X-ray imaging system. Insertion of the electrode array (10) may be performed before or after insertion of the positioner (20). That is, insertion of the electrode array may be achieved by first inserting the flexible positioner (20) into the scala tympani to a desired depth so that the positioner rests against the outer or lateral wall of the scala tympani, leaving an opening slightly larger than the cross section of the electrode array adjacent the inner wall of the scala tympani, and then second inserting the electrode array (10) into the opening defined by the positioner and inner wall. The guiding insert may be used, if desired, to assist guiding the electrode array into this opening. Alternatively, insertion of the electrode array may be achieved by first inserting the electrode array (10) into the scala tympani, and then second inserting the positioner (20) into the scala tympani so as to lie between the electrode array and the outer wall of the scala tympani. Insertion of the positioner into scala tympani after the electrode array has been at least partially inserted therein further helps carry the electrode array deeper into the scala tympani to a desired final position, and maintains it in that position.

Flexible positioner for use with implantable cochlear electrode array

Abstract: A tapered, flexible positioner, typically molded in a curved or hooked shape from a silicone polymer, is adapted to be inserted into the scala tympani duct of a human cochlea so as to position or force an electrode array, also inserted into the scala tympani duct, against the modiolar wall of the cochlea. The positioner may be inserted into the scala tympani duct before, or preferably after, insertion of the electrode array. The flexible positioner thus fills space within the scala tympani duct so as to force the electrode array, also inserted into the scala tympani duct, against the modiolar wall of the cochlea, where the electrode contacts of the electrode array may be more effective. In a preferred embodiment, a channeling groove is formed along one side of the positioner for receiving the electrode array. Also, in the preferred embodiment, a silastic tube forms a molded-in tube within the molded positioner, and provides a lumen, sealed or closed at its distal end, into which a stylet wire may be inserted during the insertion process.

Electrode for use in electro-optical devices

Abstract: An electrode for an electro-optical device is provided. Light is passing through this electrode which comprises a pattern of conductive elements. The elements have dimensions small compared to the wavelength of light, so that the electrode appear transparent. The light intensity distribution after having penetrated the electrode compared with the light intensity distribution before having penetrated the electrode is influenced by forward scattering.

Electrosurgical systems and methods with temperature control

Abstract: Vascular catheter comprises a catheter body having a proximal end, a distal end, and an electrode array disposed near the distal end. The electrode array is located proximally of a common electrode, typically located on a movable guidewire, and includes a plurality of isolated electrode terminals. By positioning the common electrode within a stenotic region and contacting a leading surface of the stenotic region with the electrode array, the stenotic material can be heated by applying a high frequency voltage between the electrode array and the common electrode. The stenotic region can thus be recannalized by advancing the distal end of the catheter body through the heated stenotic material.

Apparatus and method for perimodiolar cochlear implant with retro-positioning

Abstract: An implantable cochlear electrode array includes an electrode carrier, a groove within the electrode carrier, and a flexible element located in the groove. After the electrode array is implanted, the flexible element may be held in place while the electrode carrier may be partially withdrawn so that the electrode carrier pulls away from the flexible element which emerges from the groove through the surface of the electrode carrier, except where the electrode carrier and the flexible element are attached, so that the electrode carrier wraps around an inner scala tympani wall. A portion of the apical end of the electrode carrier may extend beyond the ends of the groove and the flexible element so that the apical end of the electrode carrier does not wrap around the inner scala tympani wall when the electrode carrier is partially withdrawn after insertion in the cochlea. The electrode carrier may include a perimodiolar section to be positioned next to an inner scala tympani wall of the cochlea, and an outer wall section to be positioned next to an outer scala tympani wall of the cochlea. Theperimodiolar section may be shorter than the outer wall section to accommodate the real length difference between the inner and outer walls of the scala tympani of a cochlea. Preferred embodiments are also directed to a method of fabricating such a cochlear electrode array by negative casting, and to a method of implanting such a cochlear electrode array.

Modiolus-hugging cochlear electrodes

Abstract: An electrode array has a flexible carrier that, when viewed in cross-section, is much more flexible in a first direction than in a second direction orthogonal thereto. The flexible direction is the direction that allows the array to readily flex so as to assume the general spiral or circular shape of the scala tympani duct within the cochlea. The less-flexible direction is the direction that makes it difficult for the array to twist as it is inserted within the scala tympani duct. By placing the electrode contacts of the array on or near that surface of the array which becomes the inner surface of the spiral shape once implantation has occurred, the electrode array may be inserted within the cochlea using minimal force, yet twisting of the array becomes unlikely during insertion or thereafter. Four separate embodiments of the electrode array are described.

Constant current programming waveforms for non-volatile memories

Abstract: An EEPROM MOSFET memory device with a floating gate and control gate stack above source and drain regions formed in a substrate self-aligned with the stack. There is a means for writing data to the floating gate electrode by applying an upwardly stepwise increasing control gate voltage V CG1 waveform applied to the control gate of the EEPROM device. The waveform is a voltage ramp providing a substantially constant tunneling current into the floating gate electrode which is approximately constant with respect to time so programming speed and the number of write/erase cycles is increased. The means for threshold voltage testing compares the voltage of the drain electrode to a reference potential. The ramped pulse output is supplied to the control gate electrode by producing a sequence of increasingly higher counts to a decoder which provides sequential switching of successively higher voltage pulses from a voltage divider, and there is means for providing ramping programming voltages to the successively higher voltage pulses.

Element driving device and method and image display device

Abstract: PROBLEM TO BE SOLVED: To prevent operation defects due to voltage drop in the case of arranging many active elements like organic EL elements and performing matrix driving. SOLUTION: When switching means 17 and 20 are turned to an ON state by the control signals of a control electrode 22, since the control current of a signal electrode 21 is converted into a control voltage by a second transistor 18, held in a voltage holding means 16 and applied to the gate electrode of a first transistor 15, the driving voltage of a power supply electrode 13 is converted into a driving current and supplied to the active element 12. Since not the control voltage but the control current is inputted to the signal electrode 21 so as to control the operation of the active element 12, even in the structure of connecting many active elements 12 to one signal electrode 21, an operation gap due to the voltage drop is not generated. Since the first and second transistors 15 and 18 form a current mirror circuit, the driving current corresponding to the control current of the signal electrode 21 is supplied to the active element 12. COPYRIGHT: (C)1999,JPO

Precurved modiolar-hugging cochlear electrode

Abstract: An electrode array has an elongate flexible carrier that, when viewed in cross-section, is much more flexible in a first direction than in a second direction orthogonal thereto. The elongate flexible carrier is formed with a bias force that causes the array to flex in the first direction so as to assume the general spiral or circular shape of the scala tympani duct within the cochlea. The less-flexible direction is the direction that makes it difficult for the array to twist as it is inserted within the scala tympani duct. The bias force is sufficiently strong to cause the array to assume its preformed spiral shape even after being straightened during initial insertion into the cochlea. Electrode contacts, embedded into the carrier so as to be exposed along an inner or concave surface of the spiral, thus wrap snugly around the modiolus, thereby positioning the electrode contacts against the modiolar wall in an optimum position for stimulation.

A flexible micromachined electrode array for a cochlear prosthesis

Abstract: A micromachined silicon electrode array intended for use as a cochlear implant is reported. The flexible array is formed using a boron etch-stop for substrate definition and contains 22 IrO stimulating sites implemented on 750 μm centers. The insertable portion of the array is 25 mm long and 320–640 μm in width; the back end of the device provides interconnects to implanted current-generation circuitry. Device functionality has been verified through in vivo experiments and the associated evoked auditory brainstem responses are reported; thresholds for monopolar stimulation are less than 80 μA. The integration of polysilicon strain gauges on the array will permit monitoring of implant curvature within the cochlea, providing a resolution in substrate position of 60 μm across the 500 μm diameter cochlear canal.

Method for enhancing and separating biopotential signals

Abstract: Disclosed is an electrode array (i.e., "sensor") and a method for separating near and far-field signals. In one embodiment a horizontal array is used, and in an alternate embodiment a vertical array is used. The electrode array consists of two well-separated pairs of closely spaced electrodes (and a separate ground element). In a typical application of collecting a channel of EEG, "sensing" electrodes are placed in standard locations (e.g., R and Ctr) with a ground electrode placed elsewhere on the head. The voltage measured between the well-separated sensing electrodes is the far-field dominant (i.e., EEG-dominant) channel. Additional electrodes are placed near each of the two sensing electrodes. (The additional electrodes are immediately lateral to the existing electrodes in the horizontal array, and are immediately above the existing electrodes in the vertical array.) The voltages measured between the pairs of closely spaced electrodes are near-field dominant (i.e., EMG/EOG-dominant) channels. The EEG, EMG and EOG signals can be enhanced by uncoupling them by combining information from all channels. The sensor is connected to a monitor via a patient interface cable (PIC). The sensor contains additional circuitry at the connection site that is used by the monitor to identify the presence and type of sensor, and to configure the monitor to invoke the appropriate software that will apply the method of the current invention to collect and uncouple the EEG, EMG and EOG.

Measuring the Ion Current in Electrical Discharges using Radio-frequency Current and Voltage Measurements

Abstract: This letter describes a technique for measuring the ion current at a semiconductor wafer that is undergoing plasma processing. The technique relies on external measurements of the radio-frequency (rf) current and voltage at the wafer electrode. The rf signals are generated by the rf bias power which is normally applied to wafers during processing. There is no need for any probe inserted into the plasma or for any additional power supplies which might perturb the plasma. To test the technique, comparisons were made with dc measurements of ion current at a bare aluminum electrode, for argon discharges at 1.33 Pa, ion current densities of 1.3–13 mA/cm2, rf bias frequencies of 0.1–10 MHz, and rf bias voltages from 1 to 200 V. Additional tests showed that ion current measurements could be obtained by the rf technique even when electrically insulating wafers were placed on the electrode and when an insulating layer was deposited on the electrode.

Stability of the cochlear implant array in children.

Abstract: Objective: To determine cochlear implant electrode stability in the young patient. Electrode migration due to future skull growth was a concern that led to prohibiting implantation in children less than 2 years of age. Recently, the high level of performance achieved by young implantees has led to a re-evaluation of this lower age limit, requiring an assessment of the effects of skull growth over time. Study Design: Prospective radiographic analysis of electrode position of cochlear implants in young children. Methods: Twenty-seven children implanted with the Nucleus (Cochlear Corp., Denver, CO) or Clarion (Advanced Bionics Inc., Sylmar, CA) multichannel cochlear prostheses were subjects for this study. Follow-up radiographic studies were obtained for a period of month to 5 years after implantation. The age at time of implantation ranged from 14 months to 5 years. An intraoperative modified Stenver's view plain radiograph was obtained as a baseline. After implantation, on a yearly basis transorbital Stenver's and base views were obtained for comparative purposes. Additional radiographs were obtained whenever a change in performance or electrode map caused suspicion for extrusion. Electrode position was determined using a computer graphics enhancement technique whereby image contrast filters enhanced the visibility of the electrode array and surrounding bony structures. Results: An analysis of the data revealed no migration of the electrode array over time. Conclusions: The confirmation of the stability of the electrode array alleviates the concern of the effects of skull growth on cochlear implantation in young children.

Organic electroluminescent device and organic electroluminescent apparatus

Abstract: An organic electroluminescent apparatus according to the present invention has an organic electroluminescent device provided with an organic layer including luminescent materials in which the emission spectrum varies depending on a voltage of an electric signal between a hole injection electrode and an electron injection electrode and voltage applying means for applying a voltage of an electric signal in a pulse shape between the hole injection electrode and the electron injection electrode, the voltage applying means changing the voltage amplitude of the electric signal in a pulse shape applied between the hole injection electrode and the electron injection electrode, to change the emission spectrum in the organic electroluminescent device.

Frequency switching type surface mounting antenna, antenna device using the antenna and communication unit using the antenna device

Abstract: PROBLEM TO BE SOLVED: To provide an antenna which can cope with plural frequency bands by switching the grounded and non-grounded states of a control electrode that is placed near the open end of a radiation electrode via a gap and accordingly switching the resonance frequency of the antenna. SOLUTION: A ground electrode 3 is formed on the entire surface of on one of both main sides of a rectangular parallelepiped-shape dielectric substrate 2 together with a radiation electrode 4 formed on the other main side of the substrate 2 respectively, and one of both ends of the electrode 4 is grounded. In such a constitution, a surface mounting antenna 1 is produced. The signal inputted to a feeding electrode 6 from a signal source 10 is inputted to the electrode 4 via a 1st gap 5 formed near the open end of the electrode 4. Thus, the electrode 4 resonances as a microstrip line resonator whose one of both ends is opened with the other end having its short circuit length of λ/4. A control electrode 8 is placed near the open end of the electrode 4 via a 2nd gap 7, and the grounded and non-grounded states of the electrode 8 are controlled by a switch 9. When the switch 9 is turned on, the capacities generated between the electrode 4 and the electrode 8 are applied in parallel to each other to lower the resonance frequency.

Cochlear electrode array employing dielectric members

Abstract: An electrode array (10, 10') for stimulation of the cochlea includes an elongated tapered carrier (15) on which a multiplicity of separately controlled electrode contacts (20) are carried. A set of flexible fins (100, 110, 120) or bumps (120') or other dielectric members extend from the carrier in particular axes so as to cause the outside dimension of the array plus the dielectric members to readily fit within the cavity wherein the array is to be inserted. The dielectric members are made from compliant, dielectric material. When formed as fins, the dielectric members can be folded against the body of the carrier as it is inserted into the cochlea so that they readily slide past obstructions and accommodate variations in the cross-sectional dimensions of the cavity, e.g., the scala tympani (5) with only modest insertion forces. When in place, the dielectric members preferably touch the walls of the cavity into which they are inserted, thereby forming a series of separate longitudinal compartments (35), at least most of which contain at least one separate stimulating electrode. The dielectric members confine electrical currents injected through most of the contacts to flow preferentially through different portions of the wall of the cavity in which the electrode array is inserted, thereby selectively stimulating/activating cells encompassed by the compartments.

Method for driving an ac-driven PDP

Abstract: A method for driving an AC-driven plasma display panel (PDP) having a three-electrode surface discharge structure constructed to have a first electrode and a second electrode both extending in a direction of a row line of elements arranged in matrix and a third electrode extending in a direction of a column line of the elements, the method including the step of applying, upon displaying images in time sequence, erase voltage pulses of different polarities for erasure to the second electrode and the third electrode so that an effective voltage exceeds an opposition discharge start voltage only in the case where a wall voltage of a predetermined value or higher is superposed on the voltage pulses, during a period from the end of sustaining the light-emission discharge for display for an image to the beginning of addressing for a next image.