Abstract: This invention enables the full-body (throughout the entire thickness) scribing of a plate made of fragile material such as glass by irradiating the work with the laser beam for heating with or without cooling and thereby generating the tensile thermal stress in the work which exceeds the cleavage toughness of the material, dispensing with the mechanical breaking. In this invention, the absorption of the beam in the work is so controlled that the beam, while being absorbed in it, is either transmitted through it or reaches the adequate thickness of the work and the entire thickness scribing is realized. This absorption control is done by selecting the laser beam wavelength so as to achieve the proper absorption in the absorption spectra of the material either due to the electronic transition or the lattice vibration.

Abstract: A laser machining apparatus with a simplified laser beam transmitting network. Respective laser beams form laser generators LS#11 to LS#25 divided into groups of G1 and G2 are aggregated to fiber-optic cables H1 and H2 by confluence devices HC1 and HC2 and transmitted to a most upstream laser beam outlet OP1. The laser beams are further aggregated to a fiber-optic cable H3 and distributed to a branch fiber-optic cable HH1 by the laser beam outlet OP1, and then distributed by laser beam outlet OP2 to OP8 to branch fiber-optic cables HH2 to HH8. The laser beams distributed to branch fiber-optic cables are focused by the machining tools TL1 to TL8 attached to robots RB1 to RB8 for laser machining. By controlling output levels of the laser generators with different oscillation wavelengths and different polarization characteristics, blend ratio of the laser beams can be adjusted. Distribution ratios of the laser beams at the laser beam outlets OP1 to OP8 are adjustable.

Abstract: A plurality of laser generators are provided to be environmentally separated from a machining station, and temperature, humidity, vibration, cleanliness and the like are detected by a sensor, and displayed. When an abnormal environment is detected, machining operation is stopped immediately or after a predetermined time elapsed. The laser generators are grouped according to each machining tool, and fiber-optic cable switching devices FC3 and FC4 are arranged for each group. By the switchover of the laser generator, and the selective connection of a fiber-optic cable by using the fiber-optic cable switching device, the degree of freedom in selecting the laser generator and the fiber-optic cable is produced.

Abstract: A laser machining apparatus with a simplified laser beam transmitting network. Respective laser beams form laser generators LS#11 to LS#25 divided into groups of G1 and G2 are aggregated to fiber-optic cables H1 and H2 by confluence devices HC1 and HC2 and transmitted to a most upstream laser beam outlet OP1. The laser beams are further aggregated to a fiber-optic cable H3 and distributed to a branch fiber-optic cable HH1 by the laser beam outlet OP1, and then distributed by laser beam outlet OP2 to OP8 to branch fiber-optic cables HH2 to HH8. The laser beams distributed to branch fiber-optic cables are focused by the machining tools TL1 to TL8 attached to robots RB1 to RB8 for laser machining. By controlling output levels of the laser generators with different oscillation wavelengths and different polarization characteristics, blend ratio of the laser beams can be adjusted. Distribution ratios of the laser beams at the laser beam outlets OP1 to OP8 are adjustable.

Abstract: A laser machining apparatus capable of performing a laser machining with an increased rate of operation. A plurality of laser generators are provided to be environmentally separated from a machining station, and temperature, humidity, vibration, cleanliness and the like are detected by a sensor, and displayed. When an abnormal environment is detected, machining operation is stopped immediately or after a predetermined time elapsed. The laser generators are grouped according to each machining tool, and fiber-optic cable switching devices FC3 and FC4 are arranged for each group. By the switchover of the laser generator, and the selective connection of a fiber-optic cable by using the fiber-optic cable switching device, the degree of freedom in selecting the laser generator and the fiber-optic cable is produced.

Abstract: A solid-state laser oscillating device which is inexpensive and capable of obtaining a high power. A plurality of laser crystals (YAG laser crystals, etc.) (1a, 1b, 1c) are arranged along the optical axis of an optical resonator so as to maintain optical contact with one another. Adjacent ones of the laser crystals have surfaces facing each other with an adhesive layer (10, 20) interposed therebetween, to form an array in a straight-line as a whole. An adhesive having a low light absorbance with respect to a laser beam of oscillation wavelength or an excitation light is used for forming the adhesive layers (10, 20). If the refractive index of the adhesive is substantially equal to that of the laser crystals, optical matching is achieved. The adhesive layers (10, 20) may be replaced by some other transparent material. The adjacent laser crystals may be arranged with a narrow gap therebetween or held in surface contact with each other.

Abstract: A laser oscillator which uses a granular laser gain medium to secure a large gain volume and is capable of suppressing resonator loss caused by granular-boundary scattering. A suspension (1), which is obtained by dispersing a number of dielectric grains doped with a luminous element in fluid having refractive index matched with that of the dielectric grains, is filled in a cell (6). The cell (6) filled with the suspension (1) is disposed in an optical resonator constituted by a rear mirror (3) and an output mirror (4). When the cell (6) is irradiated with excitation light (2), the dielectric grains in the suspension (1) are subjected to laser pumping and a laser beam (5) is output. Since the dielectric grains coexist with the refractive index-matched fluid, the granular-boundary scattering is suppressed, making it possible to provide a low-loss optical resonator. Dielectric grains with a slightly greater diameter may alternatively be distributed in filling liquid which is refractive index-matched fluid.

Abstract: In a gas laser blower, the lower end opening of the oil passage (14) extends below the liquid level of the oil reservoir (17), so that the internal chamber (18) of housing and the oil passage (14) are separated by the oil within the oil reservoir. Further, a cylindrical guard (24) is disposed around the lower bearing (6) which supports the shaft so that the oil and oil mist scattered from the bearing are caught by the guard (24) and is returned to the oil reservoir.

Abstract: A laser machining apparatus capable of performing a high-speed and high-precision machining of a workpiece. One end of each of a first-axis and a second-axis expandable arms is supported on a fulcrum. The fulcrum is angularly movably within a predetermined range about the fulcrum in a plane parallel to a machining plane. A machining head is supported at a joint point of the first-axis and second axis expandable arms. Each arm has a ball screw and a cover having an expandable and contractible tube structure, and the machining head has a ball nut threaded to engage with the ball screw. As the ball screw is rotated by a servomotor, the arm extends and contracts to move the machining head. A Z-axis adjusting mechanism is provided between a joint portion of each arm and the machining head and a machining nozzle that is disposed on a tip of the machining head. A three-dimensional parallel drive system or a combination of a serial drive system and a parallel drive system may be used to drive the machining head.

Abstract: In a blower for compulsorily circulating a laser gas for a gas laser apparatus, a shaft (2) of an impeller (1) is fitted with an intermediate member (66) that rotates together therewith, and rings (641, 642) are fitted individually in annular grooves (651, 652) formed on the intermediate member (66). On the other hand, a bearing holder (60) for holding a bearing (5) that supports the shaft (2) is provided with a ring holder (63) having an inner wall kept normally in contact with the respective outer peripheral surfaces of the rings (641, 642). As a result, narrow axial gaps between the rings (641, 642) and the annular grooves (651, 652) prevent gaseous impurities from getting into a gas laser circulation path through a bearing (5).

Abstract: A laser resonator allows internal optical mirrors to be cleaned easily and minimizes any contamination of the internal optical mirrors. The laser resonator has normally closed cleaning windows disposed immediately in front of output, rear, and folding mirrors for inserting a cleaning instrument therethrough for cleaning these mirrors. A gas inlet discharge tube holder has a discharge tube coupling which interconnects the spaces in parallel discharge tubes for transmitting a laser beam therethrough. The gas inlet discharge tube holder also has a gas flow bypass for bypassing a laser gas that circulates through the discharge tubes. The internal optical mirrors can be cleaned easily with a cleaning instrument inserted through the cleaning windows. As the internal optical mirrors do not need to be removed for cleaning, they and an external optical system are not required to be readjusted for alignment of their optical axes.

Abstract: There is provided a turbo blower for lasers which is capable of effectively cooling a shaft and bearings thereof. Oil held in a shaft support member is drawn up via an oil inlet port by a centrifugal force generated by rotation of the shaft, and passes through a cooling oil passage extending through the shaft to be discharged from an oil outlet port provided below an upper one of rolling bearings as the bearings. The oil discharged from the outlet port returns via an oil return passage to an oil sump. While passing through the oil return passage, the oil is cooled by a coolant circulating through an coolant passage. Further, part of the oil discharged from the oil outlet port is supplied to the upper one of the bearings for lubrication. On the other hand, part of the oil held within the shaft support member is drawn up along a tapered portion of an oil suction head by the centrifugal force generated by rotation of the oil suction head for lubrication of a corresponding one of the rolling bearings.

Abstract: A laser discharge tube having electrodes the peeling of which is reduced and a method of manufacturing electrodes of a laser discharge tube by which the peeling of the electrodes is reduced. The electrodes are adhered to the outside periphery of the tube wall of the laser discharge tube. The electrodes contain as components an electric conductive substance, an inorganic binder and boron nitride as a thermal expansion preventing substance for suppressing a coefficient of thermal expansion. When a silica glass tube is used as the laser discharge tube, the laser discharge tube has a coefficient of thermal expansion of +0.5.times.10.sup.-6. When the electrodes are mixed with boron nitride, the electrodes have a coefficient of thermal expansion of +2 to +7.times.10.sup.-6 and the coefficient of thermal expansion of the electrodes can be brought close to the that of the laser discharge tube by mixing boron nitride with the electrodes.

Abstract: A piercing method using a laser, in which the processing time is made shorter; a thermal runaway is prevented; and dispersion of the processing time is made smaller. According to this method, piercing operation is started with an initial pulse frequency P.sub.0 and an initial pulse duty ratio Q.sub.0, and the pulse frequency and the pulse duty ratio are increased by increments P and Q, respectively, with every passage of a predetermined time T. The pulse frequency and the pulse duty ratio are increased by stages. After this increase is repeated a predetermined number of times, or after the passage of a predetermined time from the start of processing, processing is continued to the end maintaining the increased values. This piercing method enables the processing time to be reduced to 1/3 to 1/5, as compared with the conventional method. In addition, this method prevents a thermal runaway, and reduces the dispersion of the processing time.

Abstract: A laser discharge tube for preventing the flow out of an electrode material, deterioration of electrodes, and the like, caused by corona discharge, as well as for increasing power to be supplied to the laser discharge tube by improving the heat-dissipating property and insulating property of the electrodes. The laser discharge tube is a tube of a dielectric material (e.g., silica glass) with a circular cross section and two electrode units are helically disposed on the outside periphery thereof at the same pitch. The electrode units include electrodes and dielectric layers, respectively, and each of the electrodes is formed by depositing silver as an electric conductor on the outside periphery of the tube wall by metalizing.

Abstract: A laser beam machine for carrying out a machining operation by converging a laser beam emitted from a laser resonator and irradiating the converged laser beam onto a workpiece. A beam interceptor (21) is arranged across a light path extending from a total reflection mirror (2) of the laser resonator (1) to a surface of the workpiece (5) and has a small inertia, and the position thereof is controlled at a high speed to permit the passage of the laser beam and to intercept the laser beam. The beam interceptor (21) is controlled in such a manner that the laser beam is allowed to pass during a full-scale discharge and is intercepted during a seed discharge. Accordingly, even if a seed discharge exists while a high-reflectivity material, for example, is machined, a laser oscillation of a composite resonator including the workpiece (5) can be reliably prevented.

Abstract: Surface-treated metallic workpieces such as zinc-plated steel plates are welded with high quality while they are being held in intimate contact with each other. An auxiliary gas including an oxygen gas is ejected from a space (7) around an electrode (1) through a nozzle (8) to a welding point (9) on overlapping surface-treated metallic workpieces such as zinc-plated steel plates (3a, 3b). When the zinc-plated steel plates (3a, 3b) are welded in the atmosphere of the auxiliary gas, the surface layers of zinc and oxygen react with each other, producing a solid oxide such as zinc oxide or zinc peroxide. Therefore, a gas such as a zinc vapor is prevented from being produced between the overlapping zinc-plated steel plates (3a, 3b). The welded joint is of high quality without blowholes which would otherwise blow away molten steel.

Abstract: A laser oscillating apparatus equipped with a folded-type laser resonator designed to fold an optical axis by using a reflecting mirror (11) in addition to an output coupling mirror (4) and a rear mirror (10). The rear mirror (10) consists of a roof reflector having a ridge (10a) set at an angle of .pi./4 with respect to a plane generated by a folded optical axis. At this time, the reflectance of the rear mirror (10) is higher in a linearly polarizing component having an electric-field vector parallel to the direction of the ridge (10a) than that in a component having an electric-field vector orthogonally intersecting the ridge. The laser beam in the resonator is linearly polarized in the direction of the ridge (10a) in an optical path running between the rear mirror (10) and the reflecting mirror (11) closest to the rear mirror (10). The linearly polarized beam is reflected by the reflecting mirror (11). The reflecting mirror (11) generates a total .pi.

Abstract: A laser beam machining method for cutting a workpiece in accordance with a machining program composed of a succession of move commands and laser output commands. An angle of a machining path is calculated on the basis of a move command under execution and a subsequent read out move command (S2, S3). The angle of the machining path is compared with a preset angle (S4), and when the angle of the machining path is more acute than the preset angle, the movement for machining based on the move command under execution is decelerated and stopped (S5). In this case, the laser output command is changed from a cutting condition to a piercing condition, to carry out a piercing operation, and when the piercing operation is completed, the movement for machining is restarted in accordance with the subsequent move command. When the movement for machining is restarted, the laser output command is changed from the piercing condition to the cutting condition in accordance with the movement for machining.

Abstract: A thick workpiece is cut by a laser beam of high output power. A laser beam dominantly in a ring mode, with a central region thereof being hollow, is applied to the workpiece to cut the workpiece. The laser beam dominantly in the ring mode is effective to reduce optical distortion due to laser beam absorption in a central region of a focussing optical system, e.g., a focussing lens, thereby preventing focussing characteristics from being degraded. The focussing optical system may system may be cooled by a gas applied to its surface. Alternatively, a KCL (potassium chloride) lens may be used as the focussing optical system.