Abstract: A device for holding an essentially cylindrical work piece (22), in particular a jewelry ring, for machining with a laser beam (L) has at least one chuck (20) that is supported so that it is able to rotate around a rotation axis (18) and that is provided for centrally holding the work piece (22) by means of first clamping elements (30), which automatically fix the work piece (22) in position through the exertion of a spring force.

Abstract: A method for singulating a group of semiconductor packages containing a plastic molded body. The singulation of the semiconductor packages is effected along a predetermined separation area, wherein, in the predetermined separation area, a metallic layer extending over at least a partial section of the predetermined separation area has to be cut through in addition to a plastic layer formed of a material of the molded body. The method includes the steps of: making a groove into the predetermined separation area of the semiconductor packages by laser engraving, wherein at least a part of the metallic layer extending in the predetermined singulation area is removed, and subsequent separation of the semiconductor packages by mechanical sawing cut along the predetermined separation area.

Abstract: A laser-active optical fiber for a fiber laser or an optical fiber amplifier contains a laser-active fiber core (2) comprising an undoped inner region (22) which is surrounded by an outer region (24) that is doped with a laser-active material. In this manner a high-power laser beam may be generated which has a mode structure, present in the form of a ring mode, which in particular is suitable for laser machining.

Abstract: A device for treating a substrate with laser radiation is described. The device has a rotating polygon mirror with N reflecting surfaces which are used to direct a laser beam via a system of converting focusing lenses, whereby the focal planes of the lenses are located on a surface of the substrate. Active reflecting surfaces direct the laser beam onto the converging lens system, and subsequently on the substrate, while inactive reflecting surfaces have a different inclination to the active reflecting surfaces in relation to the converging lens system. The laser beam from the surfaces is directed onto an absorber. The large number of inactive reflecting surface helps to reduce serial hole density. When the laser is switched on and off while the inactive reflecting surfaces are being scanned, further reduction of serial hole density can be achieved.

Abstract: The invention relates to a laser-processing unit, in particular a laser-welding unit, having a laser beam source (2) for generating a laser beam (LS) and having a pivotable focusing unit (8) for pivoting the laser beam (LS) about two axes of rotation (x, y) and for focusing the laser beam (LS) in a focus (F). A dichroic mirror (4) is arranged in the beam path of the laser beam (LS) between the laser beam source (2) and the focusing unit (8), which mirror is assigned an observation device (20) in such a manner that the optical axis (22) of this device coincides with the axis (24) of the laser beam (LS) as it propagates downstream of the dichroic mirror, as seen in the direction of propagation of the laser beam (LS).

Abstract: The invention relates to a method and a device for the superficial heating of tissue by means of a pulsed light source. According to the invention a series of light pulses is applied to the tissue surface. The first part of this series is configured such that the tissue surface and, by heat conduction, tissue areas situated below the tissue surface are rapidly heated to a defined target temperature without tissue removal. The subsequent part of the series results in oscillation of the temperature of the tissue areas located below the tissue surface around a value which is slightly lower than the target temperature.

Abstract: A pulsed light source for cutting away biological tissue has a control unit that controls the light source in such a way that the light source supplies a series of pulses of predetermined duration and radiation intensity. The control unit may be operated to cause the light source to supply short pulses (10) at a predetermined and/or controllable rate of repetition with a radiation intensity sufficient to cut away the tissues, and radiation followed by light emission (11) or the like with a radiation intensity that is not sufficient to cut away the tissues but is sufficient to generate heat.

Abstract: In a device for perforating cigarette paper strips, a row of adjacent optical elements (28) is disposed in the ray path of a laser beam deflected by a rotating mirror (12). Each of the optical elements includes a diffractive optical element (DOE) (24'; 24"; 24'") and a convergent lens (18'; 18"; 18'"). A parallel bundle of laser rays hits the surface of the DOE, and the DOE emits one or more bundles of rays with a desired configuration. The convergent lens produces therefrom in the plane of the cigarette paper strip (20) one or more focal spots, for example two or four mutually offset focal spots (22a, 22b) or a ring focus, so that one can form not only microperforations by individual focal spots but also macroperforations by applying energy to only the peripheral area of a macroperforation rather than the entire perforation area.

Abstract: Current supply means for a laser flash lamp contain a fast switch and control means which modulate the amplitude of each individual pulse with a presettable modulating frequency and depth of modulation. This permits higher peak envelope powers to be obtained at an unchanged mean power of the individual pulses so that the necessary threshold values can be better exceeded during materials processing. The amplitude modulation of the individual pulses also prevents undesirable shielding plasma from forming above the processing place.

Abstract: Current supply means for a laser flash lamp contain a fast switch and control means which modulate the amplitude of each individual pulse with a presettable modulating frequency and depth of modulation. This permits higher peak envelope powers to be obtained at an unchanged mean power of the individual pulses so that the necessary threshold values can be better exceeded during materials processing. The amplitude modulation of the individual pulses also prevents undesirable shielding plasma from forming above the processing place.

Abstract: In a method for the machining of material using a laser with detection of the material to be machined, laser light is directed at the material via a laser optical system and the light re-emitted by the material is guided to a first detector arrangement which measures the intensity of the light and behind which there is connected an evaluation circuit for controlling the laser power or energy. The energy fed to the material via the laser optical system is measured, and the detector arrangement supplies to the evaluation circuit a display signal which indicates the beginning of the dielectric breakdown. The evaluation circuit reduces the power of the laser and/or interrupts the laser pulse if no display signal has as yet occurred at a predetermined time at which a predetermined energy was fed to the material.

Abstract: To alleviate the adverse thermal effects of the pumping power and to increase the efficiency of the laser, a solid state laser rod is formed of a polygonal cross-section having flat, internally reflecting side surfaces extending parallel to the rod axis. A light beam applied to one end surface describes an angluar helical path within the rod to a second end surface. By passing the light beam through diverse areas of the rod, compensation for radial temperature gradients is obtained. A plurality of laser beams may traverse the rod.

Abstract: The invention relates to an apparatus for conducting a molecular gas or gas mixture containing at least one molecular component, in a closed circuit, in particular for the purpose of generating processes in the gas or gas mixture involving its partial ionization and the stimulation of molecules to vibrate in the corresponding gas component. The apparatus comprises two similarly designed flow channels preferably having a rectangular cross-section. The broadsides of the channels are arranged beside each other or constructionally integrated and are connected with each other at their adjacent ends by two apparatus for circulating gas, in such a way that the gas can flow through them in opposite directions. Electrodes are set in partial areas of each channel, electrically insulated from the channel walls, the electrode closer to the other channel in each case being electrically connected, or constructionally identical, to the corresponding electrode of this other channel.