Abstract: A self-luminous display panel including a first substrate, an insulating resin layer, self-luminous elements, a sealing layer, an attachment layer, and a second substrate, and the insulating resin layer includes an inner insulating sublayer and an outer insulating sublayer with a groove therebetween, the groove being provided in a peripheral region and surrounding an image display region, the attachment layer includes a peripheral sealing layer that is positioned inside a peripheral portion of the second substrate and a joining layer that is positioned in a range surrounded by the peripheral sealing layer, and when viewed in a cross section perpendicular to a main surface of the first substrate and across the groove, the peripheral sealing layer is at least partially positioned on the outer insulating sublayer, and an inner end portion of the peripheral sealing layer extends to the groove.

Abstract: Methods and systems are provided for operating an engine with a series gap igniter. In one example, a system may include a series gap igniter coupled to a cylinder head of a cylinder, the series gap igniter including a first spark gap in an internal volume of the series gap igniter and a second spark gap of the series gap igniter external to the internal volume of the series gap igniter and within a clearance volume of the cylinder. In this way, a cylinder with a series gap igniter may be operated to efficiently and reliably initiate combustion over a range of engine operating conditions.

Abstract: A lighting device includes a substrate having a light emitting area and a non-light emitting area surrounding the light emitting area, a light emitting part in the light emitting area, a first inorganic layer on the light emitting part and the non-light emitting area, a first organic layer on the first inorganic layer overlapping the light emitting part, a second inorganic layer on the first organic layer, a protruding part on the first inorganic layer of the non-light emitting area, and a cover layer on the protruding part.

Abstract: A spark plug assembly is provided with an insulator body extending along a longitudinal axis and defining a first face extending radially and positioned between the first and second ends. A central electrode extends through the insulator body, and a side electrode is connected to the insulator body for rotation therewith. A retainer is connected to the second end of the insulator body and defines a second face extending radially. A jacket is rotatably supported by and surrounds the insulator body. The jacket is positioned between the first and second faces, and defines an inner surface and a threaded outer surface. A bushing is rotatably supported by and surrounds the insulator body, is positioned radially between the jacket and the insulator body, and is positioned between the first and second faces. The bushing defines a tapered outer surface to mate with the inner surface of the jacket.

Abstract: An organic light-emitting display panel and a fabrication method thereof, and a display apparatus are provided. The organic light-emitting display panel has a display region and a non-display region surrounding the display region in a plan view and includes: a base substrate; a plurality of Organic Light-emitting Diode (OLED) devices, located on the base substrate and in the display region; and a first packaging film, located in both the display region and the non-display region, wherein the plurality of OLED devices are located between the first packaging film and the base substrate, and at least one opening is located in the first packaging film.

Abstract: A spark plug including a bottomed tubular insulator, a tubular metal shell, a conductive layer, and a terminal. The insulator extends along an axial line from a front end side to a rear end side and is closed at a front end. The metal shell has a ledge portion that projects radially inward and locks the insulator from the front end side. The metal shell holds the insulator from an outer peripheral side. The conductive layer covers at least a part of an inner peripheral surface of a portion of the insulator which is located on the front end side with respect to a locking portion locked by the ledge portion. The terminal is electrically connected to the conductive layer and is insulated from the metal shell.

Abstract: A spark plug having a center conductor, an insulator surrounding the center conductor, a body surrounding the insulator, and a center electrode connected in an electrically conductive manner to the center conductor, wherein the center electrode delimits a spark gap with its front face. The spark plug has two bar-shaped ground electrodes that are connected in an electrically conductive manner to the body, that delimit the spark gap, and that are adjacent to one another and spaced apart from one another in the region of the spark gap.

Abstract: A display panel comprising a first substrate and a second substrate cell-assembled with the first substrate, wherein the first substrate is provided with at least one annular protrusion made of frit with the same center point, and the second substrate is provided with an encapsulating zone to fit the annular protrusion, the encapsulating zone comprising at least one annular groove, the amount of which is less than or equal to that of the annular protrusion(s). Embodiments of the present disclosure further provide a packaging method and a display device. An OLED display panel can be ensured to have good internal sealing property by means of its package, and its service life is prolonged.

Abstract: A multi-electrode spark plug having a large spark target volume is disclosed. The spark plugs have a plurality of ground electrode rods which extend from the base of the spark plug and are twisted around center electrode to provide a plurality of substantially equidistant spark points relative to the center electrode. The spark points are formed in parallel and around the elongated axis of the spark plug. This configuration enables the spark to be created where the localized concentration of fuel to air is richer, such as that which may exist when the engine is operating with lower revolutions per minute. Test results indicate that automobiles equipped with the multi-electrode spark plugs exhibit improved fuel economy, and substantially reduced emissions and air pollution.

Abstract: A multipoint spark plug includes side electrodes provided in a pair so as to extend in a lengthwise direction of a tip end portion via a gap, and an intermediate electrode provided in the gap between the pair of side electrodes such that a plurality of ignition gaps are formed in the lengthwise direction of the tip end portion. An electrode holding portion is formed from separate parts that hold the side electrodes and the intermediate electrode, respectively, so as to insulate the side electrodes and the intermediate electrode from the main body portion, and the respective parts thereof project into the combustion chamber from the tip end portion.

Abstract: A packaging structure includes a substrate; a displaying component positioned on the substrate; a packaging cover plate arranged opposite to and spaced from the substrate; a loop of first enclosing resin arranged between the substrate and the packaging cover plate to enclose the displaying component and bond the substrate and the packaging cover plate together, where the first enclosing resin contains no spacer particle; and a loop of a second enclosing resin formed on an external circumferential area of the first enclosing resin and located between the substrate and the packaging cover plate, where the second enclosing resin is arranged to have a width smaller than a width of the first enclosing resin and contains therein spacer particles that are sized to define a predetermined spacing distance between the substrate and the packaging cover plate.

Abstract: In an organic EL display device (electroluminescence device) including an organic EL element (electroluminescence element), the organic EL element is covered with a desiccant layer. Between a TFT substrate (substrate) and an opposite substrate, a frame-shaped moisture high-permeable layer and a frame-shaped sealing member are disposed in a state successively surrounding the desiccant layer.

Abstract: A spark plug having a front end of a spark plug body that projects over a front end of an insulator, a recess that is arranged at the front end of the insulator from which a center electrode projects and forms an air spark gap with a ground electrode, an annular intermediate space that is formed by the recess between the insulator and the center electrode, and a surface of the recess that runs in an at least partially curved manner between the center electrode and the end of the spark plug body so that the recess forms an insulating section that prevents a sliding spark between the center electrode and the spark plug body.

Abstract: There is provided a spark plug for an internal combustion engine, including: a center electrode extending in the direction of an axis of the spark plug and having a core of higher thermal expansion coefficient than that of a front end thereof, the center electrode including a flanged portion radially outwardly protruding on a rear side thereof and a cylindrical portion located closer to a front end of the spark plug than the flanged portion and being smaller in diameter than the flanged portion; an insulator having an axial hole in the direction of the axis to retain the flanged portion in the axial hole with the cylindrical portion held in a loose-fit state in the axial hole; and a metal shell accommodating the insulator, wherein the spark plug satisfies the following condition: Cb<Cf where Cb is a difference between an inner diameter of the axial hole and an outer diameter of the cylindrical portion at an arbitrary axial position B in the direction of the axis; and Cf is a difference between the inner di

Abstract: The invention relates to a spark gap comprising a number of series-connected individual spark gaps which are placed in a stack arrangement, which are spaced apart from each other by insulating material discs and are provided with a spring contact, the individual spark gaps including ring-shaped or disc-shaped electrodes, and further comprising control elements for influencing the voltage distribution over the stack arrangement. According to the invention the ring-shaped or disc-shaped electrodes required to form one of the respective individual spark gaps are each inserted into an insulating body and held by same in a centered manner. The respective insulating material discs are located between and fixed by the insulating bodies.

Abstract: The invention relates to a spark gap comprising a number of series-connected individual spark gaps which are placed in a stack arrangement, which are spaced apart from each other by insulating material discs and are provided with a spring contact, the individual spark gaps including ring-shaped or disc-shaped electrodes, and further comprising control elements for influencing the voltage distribution over the stack arrangement. According to the invention the ring-shaped or disc-shaped electrodes required to form one of the respective individual spark gaps are each inserted into an insulating body and held by same in a centered manner. The respective insulating material discs are located between and fixed by the insulating bodies.

Abstract: A composite device assembled into a top of a head combustion chamber as a formed in place multiple spark ignition structure with embedded electrodes connected in a series electrical circuit spaced from a single centrally located ignition source to receive an arc from a central spark plug electrode to initiate a series multiple spark ignition within the series electrical circuit.

Abstract: A neutral electrode spark plug (10) consisting of a cylindrical metallic shell (20) having a tubular ceramic insulator (22), including an insulator tip (28) enclosed therein, and a central electrode (30) surrounded by the ceramic insulator (22). The central electrode (30) has a firing tip (36) extending from the insulator tip (28). A neutral electrode (38) extends from the insulator tip (28) providing a first spark gap that is separated from the central electrode (30). A side ground electrode (40) is attached to the metallic shell (20) and is laterally aligned with the central electrode (30) and the neutral electrode (38). The ground electrode (40) provides a second spark gap that is separated from the neutral insulator (38) and a third spark gap formed with the ground electrode (40) a distance away from the insulator tip.

Abstract: The invention is a spark plug having multiple precise spark gaps (G} with a donut shaped electrode (20) attached to the firing end of the central electrode (32), as well as a cylindrical ground sleeve (40) that is pressed on to the primary shell (36) of the spark plug. The electrode donut (20) is generally flat and laded out in a radial direction towards the ground prongs (42) that protrude up towards the firing end from the ground sleeve (40). In conjunction with their structure, allow for the generation of a spark from every single ground prong (42) on the ground sleeve (40). This is spark potential area (G). Such multiple spark potential area along with the electrode donut (20) and ground sleeve (40) relation provides a more rapid and complete combustion of the air-fuel mixture within the internal combustion engine, which, in turn, results in more torque and more horse power.

Abstract: A spark ignition engine capable of operating even with a leaner air-fuel mixture to achieve stable ignition and combustion performance. An ignition plug is fitted to a cylinder head through a sleeve, and the ignition electrode of the ignition plug is disposed in a cylinder, facing a single chamber type combustion chamber. The sleeve is formed in a blind cylindrical shape, an auxiliary chamber storing the ignition electrodes of the ignition plug is formed at the bottom part of the sleeve, and a nozzle hole allowing the auxiliary chamber to communicate with the combustion chamber is formed in the bottom part of the sleeve. The bottom part of the sleeve is projected from an explosion surface to the inside of the combustion chamber and the position of ignition by the ignition electrode is set near the explosion surface.

Abstract: An ignition plug is disclosed which includes a hollow main cell having a bendable extension part and a primary combustion chamber, an insulator mounted in the main cell, to insulate a terminal rod centrally embedded in the main cell, a central electrode having a first electrical contact arranged in the primary combustion chamber, the central electrode extending downwardly from the terminal rod while being surrounded by the insulator, a second electrical contact provided at a lower inner surface of the main cell while being arranged in the primary combustion chamber, the second electrical contact corresponding to the first electrical contact, and a cross flame ignition valve coupled to the main cell by the extension part in a bent state of the extension part, the cross flame ignition valve having a main ignition hole and auxiliary ignition holes for guiding flames from the primary combustion chamber to an interior of a cylinder.

Abstract: A plurality of electrode pairs (P1 to P8) are caused to project from a side wall of a combustion chamber (2) of an engine, and a distance between ignition gaps (G1 to G8) and the side wall of the combustion chamber (2) is varied according to the positions of the plurality of electrode pairs (P1 to P8).

Abstract: A spark plug having a pair of independent spark gaps includes a shell, inner and outer insulators, a cylindrical electrode assembly, a center wire assembly, and a pair of ground electrodes. The cylindrical electrode assembly is generally located between the two insulators and delivers a first high voltage ignition pulse to a first spark gap. The center wire assembly is located in an axial bore of the inner insulator and delivers a second high voltage ignition pulse to a second spark gap. The two insulators and two electrode assemblies are all coaxially aligned within the shell so that both insulators can be rotationally symmetrical. The first spark gap is radially oriented while the second spark gap is axially oriented, and the first and second spark gaps are located at different axial positions and can fire independently of one another. A method of assembling the spark plug is also disclosed.

Abstract: A spark plug is disclosed having at least one main electrode and at least one secondary electrode. The gaps associated with the secondary electrodes are between one third and two thirds the optimum gap distance. Resistors associated with the secondary electrodes control the current flow and therefore the voltage on the electrodes.

Abstract: A spark plug is disclosed having at least one main electrode and at least one secondary electrode. The gaps associated with the secondary electrodes are between one third and two thirds the optimum gap distance. Resistors associated with the secondary electrodes control the current flow and therefore the voltage on the electrodes.

Abstract: A spark plug structure produces sparks between a second ground electrode and a center electrode when a porcelain insulator is stained with carbon. A wear resisting member is installed on a side wall of the center electrode for minimizing the wear of the side wall caused by the sparks to increase the useful life of the spark plug. A production method is also provided.

Abstract: The present application is to provide a spark plug where a marking layer 2m under a glaze layer 2d can form a color stably, even if the Pb amount is decreased in the glaze layer. The glaze layer 2d is formed on an insulator 2 of the spark plug, and the marking layer 2m is formed under the glaze layer 2d. The glaze layer 2d contains, e.g., 1 to 25 mol % of a Zn component in terms of Zno and 5 mol % or lower, e.g., 1 mol % or lower of a Pb component in terms of PbO. On the other hand, the marking layer 2m is adjusted in kinds and amounts of metallic element components in such manners that a tint seen through the glaze layer 2d is 3 or lower in brightness specified by JIS:Z8721 as well as 3 or lower in chroma specified by JIS:Z8721, or 4 or lower in the brightness specified by JIS:Z8721 as well as 2 or lower in the chroma specified by JIS:Z8721.

Abstract: The ignition system of the present invention involves the forming of multiple ignition sparks within the fuel-burning chamber of an internal combustion engine during each cylinder combustion cycle through electrical current flow through a plurality of electrodes functioning in series and forming at least two sparking gaps where the initial and last electrode in the electrode series respectively function as anode and cathode (ground) electrodes.

Abstract: The ignition system of the present invention involves the forming of multiple ignition sparks within the fuel-burning chamber of an internal combustion engine during each cylinder combustion cycle through electrical current flow through a plurality of electrodes functioning in series and forming at least two sparking gaps where the initial and last electrode in the electrode series respectively function as anode and cathode (ground) electrodes.

Abstract: A microchannel plate (P) for receiving photoelectrons includes a plate-like substrate web (W) formed from a plurality of micro-tubules (10) of a single type of cladding glass (12) and defining a pair of opposite faces (14a and 14b). The substrate web (W) further includes a plurality of microchannel passages (16) extending between the opposite faces (14a and 14b) and having openings (18a and 18b, respectively) in both of the opposite faces (14a and 14b). The microchannel openings (18) have funnel-like entries or openings (20) formed in the substrate web (W) with at least one of the opposite faces (14).

Abstract: A spark plug having a tubular metallic housing has an internal conductor arrangement including a refractory erosion. The refractory erosion resistor is designed either as a wound wire resistor or a filament-like thin-layer resistor.

Abstract: An improved structure of a spark plug in which sparks are produced between a second ground electrode and a center electrode when a porcelain insulator is stained with carbon is provided. A wear resisting member is installed on a side wall of the center electrode for minimizing the wear of the side wall caused by the sparks to increase the useful life of the spark plug. A production method is also provided.

Abstract: A spark plug derives an extended lifetime because a large plurality of sharp edges are provided on the center electrode, the ground electrode, or both to enhance spark propagation. In a first embodiment, the ground electrode has a conventional cantilever shape, but the center electrode extends into coplanar relation to a distal surface of the electrode so that sparks propagate from the cylindrical side walls of the center electrode. In variations of the first embodiment, the number of cantilevered ground electrodes is increased, with the ground electrodes being circumferentially and equidistantly spaced about the center electrode. In another embodiment, the ground electrode has an annular configuration and includes a cylindrical annular wall spaced radially outwardly of the cylindrical sidewall of the center electrode, in concentric relation to the center electrode.

Abstract: An apparatus and method for the creation, placement and control of an area of electrical ionization within an internal combustion engine combustion chamber. This area of electrical ionization is positioned so that all of the fuel being injected into the combustion chamber must pass next to or through the area of electrical ionization to ensure that combustion has been initiated for all of the fuel as it is injected. This area of electrical ionization can be kept on as long as it is necessary to insure that the all of the fuel that is injected into the combustion chamber can be completely combusted. An engine equipped with this electrical ionization device has its fuel economy enhanced by timely, controlled, and complete combustion of all of the fuel injected into its combustion chamber. Furthermore, the pollutant emissions of both oxides of nitrogen and unburned hydrocarbons are reduced dramatically.

Abstract: A spark plug derives an extended lifetime because a large plurality of sharp edges are provided on the center electrode, the ground electrode, or both to enhance spark propagation. In a first embodiment, the ground electrode has a conventional cantilever shape, but the center electrode extends into coplanar relation to a distal surface of the electrode so that sparks propagate from the cylindrical side walls of the center electrode. In variations of the first embodiment, the number of cantilevered ground electrodes is increased, with the ground electrodes being circumferentially and equidistantly spaced about the center electrode. In another embodiment, the ground electrode has an annular configuration and includes a cylindrical annular wall spaced radially outwardly of the cylindrical sidewall of the center electrode, in concentric relation to the center electrode.

Abstract: The shortest distance (F, F′) from an end face (11A) of each ground electrode (11, 11′) to a porcelain insulator (1) is made smaller than the shortest distance (G, G′) from the end face (11A) of each ground electrode (11, 11′) to the peripheral side surface of a central electrode (2, 2′). An anti-spark consumption member (21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32) is secured to a portion of the central electrode (2, 2′) in such a way that it is spaced at least a specified distance (H) of from the end face of the porcelain insulator (1).

Abstract: In a spark plug having a center electrode, first and second ground electrodes, an insulator and a metal housing, a first discharge gap is constituted between a front end of the center electrode and a front side of the first ground electrode and a second discharge gap is constituted between a front end of the second electrode and a front side of the center electrode. Respective dimensional relationships of A, B, C, H, F and L1 are defined where A is a distance of the first discharge gap, Bis a shortest distance between the front end of the second ground electrode and the insulator, C is an axial length from a leading end of the metal housing and a front end of the insulator, H is an axial length from the front end of the insulator and the front end of the center electrode, F is an axial length from the front end of the insulator to the front end edge of the second electrode and L1 is a shortest axial length from the leading end of the metal housing to the front end of the second ground electrode.

Abstract: A spark plug derives an extended lifetime because a large plurality of sharp edges are provided on the center electrode, the ground electrode, or both to enhance spark propagation. In a first embodiment, the ground electrode has a conventional cantilever shape, but the center electrode extends into coplanar relation to a distal surface of the electrode so that sparks propagate from the cylindrical side walls of the center electrode. In variations of the first embodiment, the number of cantilevered ground electrodes is increased, with the ground electrodes being circumferentially and equidistantly spaced about the center electrode. In another embodiment, the ground electrode has an annular configuration and includes a cylindrical annular wall spaced radially outwardly of the cylindrical sidewall of the center electrode, in concentric relation to the center electrode.

Abstract: An internal combustion engine spark plug having an inside annular groove at the end of its shell that accommodates a replaceable ground electrode that consists of a circular wire of durable metal that fits the annular groove and having ends that are pre-formed to terminate adjacent to the peripheral edge of the center electrode providing a double spark gap.

Abstract: A spark plug derives an extended lifetime because a large plurality of sharp edges are provided on the center electrode, the ground electrode, or both to enhance spark propagation. In a first embodiment, the ground electrode has a conventional cantilever shape, but the center electrode extends into coplanar relation to a distal surface of the electrode so that sparks propagate from the cylindrical side walls of the center electrode. In variations of the first embodiment, the number of cantilevered ground electrodes is increased, with the ground electrodes being circumferentially and equidistantly spaced about the center electrode. In another embodiment, the ground electrode has an annular configuration and includes a cylindrical annular wall spaced radially outwardly of the cylindrical sidewall of the center electrode, in concentric relation to the center electrode.

Abstract: In a spark plug, a metal shell has first and second open ends. A ground electrode is formed in integral with the metal shell, provided on the first open end of the metal shell. An insulator has an axial bore, held in the metal shell. A center electrode in the bore of the insulator has a front end extending beyond the insulator. At least one row of intermediary electrode strips is arranged intermittently in a circumferential direction around an end portion of the insulator so as to form a series of spark discharge gaps circumferentially around the end portion of the insulator, and disposed between the ground electrode and the end portion of the center electrode.

Abstract: A spark plug with improved wear resistance includes an outer conductive housing, a ceramic insulator positioned within the housing, and a central electrode inside the insulator. One or more ring-shaped auxiliary electrodes are positioned on the ceramic insulator between the central electrode and the outer conductive housing. The one or more ring-shaped auxiliary electrodes have a central portion and peripheral edges which are thickened with respect to the central portion. The spark plug provides a spark gap between the central electrode and the auxiliary electrode and between the auxiliary electrode and the conductive housing.

Abstract: A spark plug (10), for example for an internal combustion engine, having at least one center electrode (11) (high-voltage electrode) and at least one earth electrode (12), and an insulating spark plug insulator (13) and a creepage spark gap (14) between the center electrode (11) and the earth electrode (12). The creepage spark gap (14) has a pattern of islands comprising electrically-conductive material (16) which are insulated with respect to one another and are located on the outer surface zone of the spark plug insulator (13) or on the surface zone of an insulating material wafer (17) attached to outer surface of the insulator (13) of the spark plug (10).

Abstract: A spark plug for internal combustion engines ensures the formation of two spark paths. These two spark paths are a pure air spark which jumps over from electrode to electrode, and a creepage spark which emerges from the central electrode, creeps along the insulator and then jumps over at the point at the smallest distance between the insulator and the earth electrode. The spark plug includes a cylindrical metal tube which forms a housing and in which the central electrode is arranged, surrounded centrally by an insulator. The earth electrodes mounted on the metal tube are partially bent so that an obtuse bending angle of the bent-over part with respect to the part of the earth electrode which extends in the direction of the rotationally symmetrical longitudinal axis is produced.

Abstract: A spark plug having a low discharge voltage and good ignition performance. The object is achieved by means of a structure which satisfies the conditions:g3.gtoreq.1.2-g1;g2.ltoreq.g3-(d2-d1)/2;g1.ltoreq.g2.ltoreq.1.6; and0.ltoreq.h.ltoreq.2when the first spark gap size is made to be g1 mm, the second spark gap size is made to be g2 mm, the shortest distance between the center electrode tip surface peripheral portion and the second ground electrode tip surface outer end portion is g3 mm, the center electrode tip portion diameter is d1 mm, the center electrode body diameter is d2 mm, and height from an edge of said tip surface of said second ground electrode to said tip surface is h min.

Abstract: In a spark plug insulator for use in an internal combustion engine, a sintered body has boron nitride and a metal oxide, the boron nitride of the sintered body being 80% or greater by weight, and the sintered body having a thermal expansion coefficient of less than 5.0.times.10-.sup.6 /.degree.C. The metal oxide is selected alone or in combination from the group consisting of magnesium oxide, calcium oxide, silicon oxide, boron oxide, yttrium oxide and aluminum oxide.

Abstract: An ignition system has a series-gap discharge-bulb through which a high voltage is supplied to a center electrode of an ignition plug. A short-circuit element is made of a material that reversibly deforms when it is heated to a predetermined temperature when an engine is operated in a steady state. The short-circuit element is electrically connected to the plug such that two discharging electrodes are short-circuited by the short-circuit element when the short-circuit element is heated to thermally deform. The discharging electrodes may be made of a reversibly deformable material so that the electrodes deform into contact with each other when they are heated to a predetermined temperature.

Abstract: The spark device of the present invention includes a line of spaced apart conductor segments which have small spark gaps therebetween. One end of the line of segments is connected to a source of electrical energy, and the other end is connected to ground. Upon applying electrical energy to the line of segments, a plurality of sparks are emitted simultaneously at each of the spark gaps. The device can be in the form of a conventional spark plug or can be embedded in a circular body mounted to the combustion engine as part of the gasket assembly.

Abstract: A spark igniter circuit is provided for igniting a flammable gas mixture in devices such as gas torches, lanterns, stoves and the like. A piezoelectric spark generator imposes a voltage on an electrically conductive circuit which is discontinuous in two locations for creating a pair of spark gaps in the circuit. The first spark gap eliminates the need of stripping insulation from a pair of wires and providing a connector therebetween and possibly enhances the effectiveness of a spark at the second spark gap for igniting the gas mixture.

Abstract: In a spark plug with combined surface and air spark paths comprising a center electrode, and insulator which surrounds the center electrode and which, at least in the end region of the center electrode, maintains a gap with respect thereto, and a ground electrode which, together with the spark plug body, surrounds the insulator and which at least in the end region of the insulator maintains a gap with respect thereto, the insulator, to form a discharge chamber surrounding the end portion of the center electrode, extends in the axial direction of the plug beyond the center electrode, and the ground electrode encompasses the insulator around the end thereof with an extension of the ground electrode extending into the discharge chamber with a clearance gap being maintained between the extension and the end portion of the insulator.