Abstract: A first member and a second member are held by being sandwiched by first and second holders. By providing force, which brings N nails (N is an integer that is 2 or greater) of chucks closer to each other, to the N nails, each of L nails contacts the first member without contacting the second member and each of M nails contacts the second member without contacting the first member. By separating the second holder from the second member, the N nails get even closer to each other, and the second member is moved relative to the first member, then a relative position of the first and second members is adjusted. By making the second holder contact with the second member again, the first and second members are held. After removing the chucks from the first and second members, a contact portion of the first and second members is laser-welded.

Abstract: A first member and a second member are held by being sandwiched by first and second holders. By providing force, which brings N nails (N is an integer that is 2 or greater) of chucks closer to each other, to the N nails, each of L nails contacts the first member without contacting the second member and each of M nails contacts the second member without contacting the first member. By separating the second holder from the second member, the N nails get even closer to each other, and the second member is moved relative to the first member, then a relative position of the first and second members is adjusted. By making the second holder contact with the second member again, the first and second members are held. After removing the chucks from the first and second members, a contact portion of the first and second members is laser-welded.

Abstract: A method for manufacturing a spark plug includes a transfer step of transferring a first tip to a joining position where the first tip is joined to a tip-mating member. The transfer step includes a step of performing positional correction for the first tip before the first tip reaches the joining position.

Abstract: A method of manufacturing an electrode composite for forming an electrode of a spark plug, the electrode composite being formed by laser-welding a first electrode member and a second electrode member together.

Abstract: A method for manufacturing a spark plug includes a transfer step of transferring a first tip to a joining position where the first tip is joined to a tip-mating member. The transfer step includes a step of performing positional correction for the first tip before the first tip reaches the joining position.

Abstract: A method of manufacturing an electrode composite for forming an electrode of a spark plug, the electrode composite being formed by laser-welding a first electrode member and a second electrode member together.

Abstract: A method of manufacturing a projection optical system (37) for projecting a pattern from a reticle to a photosensitive substrate, comprising a surface-shape-measuring step wherein the shape of an optical test surface (38) of an optical element (36) which is a component in the projection optical system is measured by causing interference between light from the optical surface (38) and light from an aspheric reference surface (70) while the optical test surface (38) and said reference surface (70) are held in integral fashion in close mutual proximity. A wavefront-aberration-measuring step is included, wherein the optical element is assembled in the projection optical system and the wavefront aberration of the projection optical system is measured.

Abstract: A method of manufacturing a projection optical system (37) for projecting a pattern from a reticle to a photosensitive substrate, comprising a surface-shape-measuring step wherein the shape of an optical test surface (38) of an optical element (36) which is a component in the projection optical system is measured by causing interference between light from the optical surface (38) and light from an aspheric reference surface (70) while the optical test surface (38) and said reference surface (70) are held in integral fashion in close mutual proximity. A wavefront-aberration-measuring step is included, wherein the optical element is assembled in the projection optical system and the wavefront aberration of the projection optical system is measured.

Abstract: A method of manufacturing a projection optical system (37) for projecting a pattern from a reticle to a photosensitive substrate, comprising a surface-shape-measuring step wherein the shape of an optical test surface (38) of an optical element (36) which is a component in the projection optical system is measured by causing interference between light from the optical surface (38) and light from an aspheric reference surface (70) while the optical test surface (38) and said reference surface (70) are held in integral fashion in close mutual proximity. A wavefront-aberration-measuring step is included, wherein the optical element is assembled in the projection optical system and the wavefront aberration of the projection optical system is measured.

Abstract: Apparatus and methods are disclosed for measuring the surface topography of a test surface, such as a spherical or aspherical surface of a refractive or reflective optical element. The test surface is measured by detecting the state of interference fringes generated by interference of a reference light beam and a measurement light beam that interacts (e.g., reflects from) the test surface. The reference and measurement beams are produced by a point light source having a reflective surface. The point light source is disposed between a source of input light and the test surface. The measurement beam (after interacting with the test surface) and the reference beam are caused to interfere with each other to produce a first interference-fringe state. The distance between the point light source and the test surface can be changed between production of the first interference-fringe state and production of a second interference-fringe state.

Abstract: A method of manufacturing a projection optical system (37) for projecting a pattern from a reticle to a photosensitive substrate, comprising a surface-shape-measuring step wherein the shape of an optical test surface (38) of an optical element (36) which is a component in the projection optical system is measured by causing interference between light from the optical surface (38) and light from an aspheric reference surface (70) while the optical test surface (38) and said reference surface (70) are held in integral fashion in close mutual proximity. A wavefront-aberration-measuring step is included, wherein the optical element is assembled in the projection optical system and the wavefront aberration of the projection optical system is measured.

Abstract: A method of manufacturing a projection optical system (37) for projecting a pattern from a reticle to a photosensitive substrate, comprising a surface-shape-measuring step wherein the shape of an optical test surface (38) of an optical element (36) which is a component in the projection optical system is measured by causing interference between light from the optical surface (38) and light from an aspheric reference surface (70) while the optical test surface (38) and said reference surface (70) are held in integral fashion in close mutual proximity. A wavefront-aberration-measuring step is included, wherein the optical element is assembled in the projection optical system and the wavefront aberration of the projection optical system is measured.