Abstract: A plasma jet ignition plug having high ignition performance and high durability. The plasma jet ignition plug comprises a center electrode wherein at least a front end portion including a front end surface of the center electrode contains an oxide of at least one of the rare earth elements in a total amount of 0.5% by mass to 10% by mass inclusive and tungsten (W) in an amount of 90% by mass or greater, or contains iridium (Ir) in an amount of 0.3% by mass to 3% by mass inclusive and W in an amount of 97% by mass or greater.

Abstract: A plasma jet ignition plug including an insulator having an axial hole extending therethrough in the direction of an axis CL1, a center electrode inserted into the axial hole, and a ground electrode disposed frontward of the front end of the insulator. The insulator has a cavity defined by the wall surface of the axial hole and the front end surface of the center electrode and opens frontward. The ground electrode has a through hole for establishing communication between the cavity and an ambient atmosphere. A front end portion of the center electrode is formed into a taper portion whose diameter reduces frontward in the direction of the axis CL1. The outside diameter of a front end of the taper portion is smaller than the diameter of the through hole. The cavity has a substantially constant diameter with respect to the direction of the axis CL1.

Abstract: A plasma jet spark plug for igniting an air-fuel mixture in a conventional combustion device such as an internal combustion engine.

Abstract: A spark plug having an electrode, an insulator, a metallic shell, a main ground electrode, and at least two auxiliary ground electrodes.

Abstract: A spark plug including: a center electrode; a substantially cylindrical insulator; a cylindrical metal shell; a ground electrode having a base end joined to a leading end portion of the metal shell and a distal end bent toward the axis line. The ground electrode includes: a thick portion provided on a base end side, a thin portion provided on a distal end side, and a stepped portion provided on an inner peripheral surface between the thick portion and the thin portion. A noble metal tip is joined to and partially embedded in the inner peripheral surface of the thin portion and disposed to form a gap between the noble metal tip and the leading end portion of the center electrode.

Abstract: A spark plug including: a ground electrode including a thick portion provided on a base end side, a thin portion provided on a distal end side, and a stepped portion provided on an inner peripheral surface between the thick portion and the thin portion; a noble metal tip partially embedded in an inner peripheral surface of the thin portion; and a bulge portion provided on the inner peripheral surface of the thin portion between the stepped portion and the noble metal tip. When viewed from a side surface of the ground electrode, a relationship [a protruding height of the noble metal tip from the inner peripheral surface of the thin portion]?[a protruding height of the bulge portion from the inner peripheral surface of the thin portion].

Abstract: A spark plug without any noble metal chip on a ground electrode and capable of enhancing the ignition property, prolonging the life and ensuring a sufficiently high strength of the ground electrode is provided. The spark plug 1 includes a center electrode 5, an insulator 2, a metal shell 3, and a ground electrode 27. Spark discharge is provided substantially along a direction of an axis CL1 of the spark plug in a spark discharge gap 33 defined between the center electrode 5 and the ground electrode 27. The ground electrode includes a narrowed width portion 42 which has a substantially uniform width smaller than an outer diameter of a tip end surface 5F of the center electrode 5, and a widened width portion 41 having a width larger than the width of the narrowed width portion 42.

Abstract: It is an object of the present invention to provide a spark plug that can be produced at low cost and secure compatibility between ignition performance and durability. The spark plug according to the present invention includes a center electrode and a ground electrode having an inner surface facing the center electrode, characterized in that; the ground electrode has a protrusion and a hole; the protrusion protrudes from the inner surface by a protruding length A of 0.4 to 1 mm and has a first straight portion with a projected first straight portion area S1 of 1.5 to 3 mm2; the hole has an opening at an outer surface of the ground electrode, a second straight portion, a bottom portion and a transition portion; the opening is formed in such a manner that the ratio (S2/S1) of a projected opening area S2 of the opening to the projected first straight portion area S1 is not less than 1.2; and the transition portion is in the form of a taper portion.

Abstract: An optical disk device includes a test recording portion, a power control portion, a recording portion and a power correction portion. The power control portion determines a first recording power to record recording information to the optical disk based on test information recorded by the test recording portion. The power correction portion calculates a first average of modulation of the recording information recorded on a first track of the optical disk at the first recording power and a second average of modulation of the recording information recorded on a second track of the optical disk at the first recording power. The power correction portion increases the first recording power to a second recording power when the second average of the modulation drops below a first threshold value that is preset and drops below a second threshold value that is calculated based on the first average of modulation.

Abstract: A spark plug includes a ground electrode formed with a flat region and a convex curved region on an outer peripheral surface thereof. The flat region is located on a front end of the ground electrode and has a length of 0.2 mm or more from a front end face of the ground electrode in a longitudinal direction of the ground electrode. The ground electrode satisfies the following dimensional condition (1) with respect to first and second cross sections of the ground electrode taken through the convex curved region and the flat region in directions perpendicular to the longitudinal direction of the ground electrode, 0.950?(S2/L2)/(S1/L1)?0.995 ??(1) where S1 is the area of the first cross section; L1 is the perimeter of the first cross section; S2 is the area of the second cross section; and L2 is the perimeter of the second cross section.

Abstract: A corner of a distal end of a ground-electrode-side noble metal tip of a spark plug is taken as a first corner; a corner of a leading end of a center-electrode-side noble metal tip is taken as a second corner; a corner formed at a starting point where a diameter of the center electrode is reduced is taken as a third corner; a corner of the ground electrode is taken as a fourth corner; a corner closest to the third corner of the corners on the distal end of the ground-electrode-side noble metal tip is taken as a fifth corner; a length of a virtual flying spark path defined between the first corner and the second corner is taken as L1; a length of a virtual flying spark path defined between the third corner and the fourth corner is taken as L2; a length of a virtual flying spark path defined between the third corner and the fifth corner is taken as L3; and L2 or L3, whichever is shorter, is taken as L4, the spark plug fulfills a relational expression of L4/L1?1.1.

Abstract: A spark plug includes a center electrode extending along an axial line, a ground electrode, and a noble metal tip. A center axis of the noble metal tip is displaced from a center axis of the ground electrode toward a base-end side in the axial line. The ground electrode includes an outer layer and an inner layer, and a distal end of the inner layer is closer to the axial line than a base end of the ground electrode. An overlap area between the inner layer and the noble metal tip occupies a ratio of 25% or more in a projective plane defined by projecting, along the center axis, a plane of the ground electrode viewed from a distal-end face on a cross section of the ground electrode in which a maximum cross-sectional area of the inner layer is achieved, among cross sections orthogonal to the center axis.

Abstract: A spark plug including a center electrode; an insulator; and a metal shell, wherein the metal shell includes: a mounting portion; a cylindrical portion; a seal portion; a crimping portion; and a buckled portion all as defined herein, and a relationship A<B is satisfied, in which A is a length in the axial direction of an external thread formed on the mounting portion, and B is a length of the cylindrical portion in the axial direction.

Abstract: A spark plug includes an outer electrode including an outer electrode tip of which a distal end surface is spaced from an outer peripheral surface of a leading end portion of a center electrode to define a spark discharge gap. A protruding insulator portion of a cylindrical insulator protrudes at least 1.0 mm from a leading end surface of a cylindrical metal shell. A protruding center electrode portion of the center electrode protrudes at least 3.5 mm from the leading end surface of the cylindrical metal shell. A relationship (?1+?2)/2?75 degrees is satisfied where the angle ?1 is defined as a central angle (degrees) of a first circular sector having a point B1 as a center thereof, and the angle ?2 is an average value (degrees) of the central angles of two second circular sectors having the point B1 as a center thereof.

Abstract: A spark plug including a center electrode and a ground electrode. A center electrode noble metal tip is joined to a leading end portion of a center electrode, and a ground electrode noble metal tip is joined to a center-electrode-side side surface of the ground electrode. A distal end portion of the ground electrode noble metal tip protrudes from a distal-end surface of the ground electrode by 0.1 mm to 1.5 mm. A center-electrode-side side surface of the ground electrode noble metal tip projects from a center-electrode-side side surface by 0.15 mm to 0.6 mm. The ground electrode includes chamfered portions. Thickness lengths and widthwise lengths of the respective chamfered portions achieved within a cross section perpendicular to a center axis of the ground electrode are set to 0.2 mm or more.

Abstract: A center electrode includes a tapered electrode base member mount and a noble metal tip joined to the electrode base member mount via a fused portion in which the component of the noble metal tip and the component of the electrode base member mount are fused. In this state, the cross section area S1 at a tip side boundary between the fused portion and the noble metal tip and the cross section area S2 at a base member side boundary between the fused portion and the electrode base member mount satisfy the relational expression of S1<S2. Regarding the cross section area S3 at the base portion of the electrode base member mount, (S3?S2)/D satisfies the relational expression of 5?(S3?S2)/D?50. D is the shortest distance in the axis line direction from the base member side boundary to the base portion.

Abstract: A plasma jet ignition plug including a wire-wound resistor for restraining the radiation of noise while allowing application of a sufficiently large current for generation of plasma to a spark discharge gap at the time of ignition. The wire-wound resistor having an inductance of 1 ?H to 100 ?H inclusive and a resistance of 1? or less, and is provided on at least one of a center electrode and a ground electrode. The wire-wound resistor restrains current which is generated by the influence of stray capacitance present in the plasma jet ignition plug, thereby reducing noise.

Abstract: A spark plug including a ground electrode which has an excellent heat sinking ability. The ground electrode includes a core material therein. Heat received from a combustion chamber during a drive of an internal-combustion engine can be conducted to the core material. More effective heat sinking ability can be achieved because of the core material.

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 present invention provides a niobium 2-ethylhexanoate derivative having a niobium content of from 13 to 16 mass % and a carbon content within a range of from 50 to 58 mass %, the niobium 2-ethylhexanoate derivative consisting only of: niobium atoms, oxygen atoms, and 2-ethylhexanoic acid residues; the niobium 2-ethylhexanoate derivative can be produced by reacting pentakis(alkoxy)niobium with 2-ethylhexanoic acid; further, the organic acid metal salt composition of the present invention includes the niobium 2-ethylhexanoate derivative, a metal precursor other than niobium, and at least one kind of an organic solvent; and the thin film including a niobium element and metal other than niobium can be formed on a substrate by applying the organic acid metal salt composition on the substrate and heating the substrate with the applied organic acid metal salt composition.