Abstract: A laser welding device (10) for welding a weld part (35) with laser light (L) includes: a laser emitting head (20) overlapping the laser light (L) and a measurement light (S) coaxially with each other and applying the laser light (L) and the measurement light (S) to the weld part (35), the measurement light (S) having a wavelength different from a wavelength of the laser light (L); a first parallel plane plate and a second parallel plane plate, changing an irradiation position of the measurement light (S) such that the irradiation position orbitally move around a center of rotation that moves on a predetermined welding path in a radius of rotation that is smaller than ½ of a spot diameter of the laser light (L); a measuring instrument (14) repeatedly measuring a weld penetration depth of the weld part (35) based on the measurement light (S) that is emitted from the laser emitting head (20) and is reflected on the weld part (35) while the measurement light (S) is being orbitally moved; and a determiner (17) de

Abstract: A phase-contrast microscope includes a light source section configured to emit light; a light guide including a plurality of optical fibers, the light guide transmitting the light emitted from the light source section through the plurality of optical fibers; and an object lens including a lens and an annular phase film, the annular phase film being on the side to which light passes through the lens, the object lens being configured to enlarge an image on a sample irradiated with the light transmitted by the light guide. The plurality of optical fibers include a plurality of emission faces arranged to form a ring, and the light guide is disposed in such a manner that the plurality of emission faces are in a conjugate position to the annular phase film.

Abstract: A laser welding apparatus includes: a laser oscillator configured to emit a laser beam toward a welding portion of a welded material; an optical interferometer configured to generate an interference signal that indicates an intensity of an interference beam of a measurement beam reflected by the welding portion and a reference beam; and a derivation unit configured to generate, based on the interference signal, two-dimensional tomographic image data indicating a correlation among a distance in a proceeding direction of welding of the welding portion, a depth of the welding, and an intensity of the interference signal, to extract specified depth tomographic image data within a specified range from the two-dimensional tomographic image data, and to derive a depth for each distance based on the intensity of the interference signal in the specified depth tomographic image data.

Abstract: Laser welding is performed while moving irradiation positions of a laser beam and a measurement beam in forward, rightward, rearward and leftward directions, and the penetration depth of a weld portion is measured during laser welding in each of the directions. Then, a direction in which a value smaller than a reference value is measured is determined to be an optical axis deviation direction, and a correction value is added to the values measured during the laser welding when the laser welding is performed in the optical axis deviation direction.

Abstract: A laser welding device (10) for welding a weld part (35) with laser light (L) includes: a laser emitting head (20) overlapping the laser light (L) and a measurement light (S) coaxially with each other and applying the laser light (L) and the measurement light (S) to the weld part (35), the measurement light (S) having a wavelength different from a wavelength of the laser light (L); a first parallel plane plate and a second parallel plane plate, changing an irradiation position of the measurement light (S) such that the irradiation position orbitally move around a center of rotation that moves on a predetermined welding path in a radius of rotation that is smaller than 1/2 of a spot diameter of the laser light (L); a measuring instrument (14) repeatedly measuring a weld penetration depth of the weld part (35) based on the measurement light (S) that is emitted from the laser emitting head (20) and is reflected on the weld part (35) while the measurement light (S) is being orbitally moved; and a determiner (17)

Abstract: A laser welding apparatus includes: a laser oscillator configured to emit a laser beam toward a welding portion of a welded material; an optical interferometer configured to generate an interference signal that indicates an intensity of an interference beam of a measurement beam reflected by the welding portion and a reference beam; and a derivation unit configured to generate, based on the interference signal, two-dimensional tomographic image data indicating a correlation among a distance in a proceeding direction of welding of the welding portion, a depth of the welding, and an intensity of the interference signal, to extract specified depth tomographic image data within a specified range from the two-dimensional tomographic image data, and to derive a depth for each distance based on the intensity of the interference signal in the specified depth tomographic image data.