Abstract: A shutter unit capable of preventing the scattering of the laser beam upon closing the optical path of the laser beam and capable of being miniaturized, and a laser processing device employing such a shutter unit. In a shutter unit 1, when the optical path of the laser beam L is opened, a rotating member 57 is rotated around an axis line ?, and an opening 61 is positioned on an optical axis ? so as to pass the laser beam L therethrough. Meanwhile, when the optical path of the laser beam L is closed, the rotating member 57 is rotated and a reflective surface 62 is positioned on the optical axis ? so as to reflect the laser beam L. Here, since the reflected laser beam L is absorbed by an optical absorption member 63, it is possible to prevent the scattering of the laser beam L when the optical path of the laser beam L is closed.

Abstract: A laser condensing optical system of the present invention includes a laser beam source which emits a laser beam, a condensing optical system which is arranged between the laser beam source and a medium and condenses the laser beam in the medium, and a laser divergence point moving unit which can move the position of a laser divergence point of the laser beam along an optical axis of the laser beam in accordance with the refractive index of the medium in which the laser beam is desired to be condensed and the distance from a surface of the medium to a position where the beam is desired to be condensed.

Abstract: A laser processing apparatus which can suppress the positional fluctuation in light-converging point of laser light during laser processing is provided. On an optical path of laser light L1 connecting a beam expander 34 and a first light-transmitting hole 32 of a lens holder 29 to each other in a laser processing apparatus 20, a stop member 38 including a second light-transmitting hole 39 having the same diameter as that of the first light-transmitting hole 32 is disposed. Hence, the amount of laser light L1 cut by the surrounding part of the first light-transmitting hole 32 can substantially be eliminated, whereby the lens holder 29 can be prevented from being heated upon irradiation with the laser light L1. Also, even when the stop member 38 is heated by the laser light L1 cut by the surrounding part of the second light-transmitting hole 39, heat is prevented from being transmitted from the stop member 38 to the lens holder 29, since the stop member 38 is separated from the lens holder 29.

Abstract: A light emitting end face side front end part of an optical fiber bundle 16 is covered by a sleeve member 13 and an emitting part outer cover 14. A glass rod holding member 42, which holds a glass rod 40, is mounted to emitting part outer cover 14. Glass rod 40 is fixed to glass rod holding member 42 by means of positioning pins 44 and a light incidence end face 40i thereof opposes a light emitting end face 16o of optical fiber bundle 16. A light emitting end face 40o of glass rod 40 has a rectangular shape. The light emitting from light emitting end face 40o is made uniform in illuminance across the entirety of its cross section and the cross section thereof is shaped to a rectangular shape in the process of being propagated while being totally reflected at the boundary surface of glass rod 40.