Abstract: Provided is a zoom lens that has a four-lens configuration and is capable of having a viewing angle of larger than 180°. Provided is an infrared zoom lens that has a long back focus. The present invention comprises a first lens group that has a negative refractive power, and a second lens group that has a positive refractive power. During zooming, the first lens group and the second lens group move on an optical axis, and each of the first lens group and the second lens group is configured of two single lenses.

Abstract: The present invention is directed to an infrared zoom lens that consists merely of optical components of germanium so as to implement an optical system that is capable of reducing variation in brightness during varying a magnification rate and is quite bright and that facilitates compensating for aberration, especially spherical aberration that is generally hard to do, thereby producing a clear and vivid image. The infrared zoom lens comprises first to fourth groups of lens pieces arranged in series from the foremost position closest to the object; each of the lens groups having all the lens pieces made of germanium, and at least one of the lens groups consisting simply of a single lens piece.

Abstract: An imaging lens includes, sequentially from an object side, a first lens (L11) configured by a negative meniscus lens disposed with the convex surface on the object side; a second lens (L12) configured by a positive biconvex lens; a negative third lens (L13); and a fourth lens group (L14) configured by a positive meniscus lens disposed with the convex surface on the image plane IMG side. By satisfying given conditions, the imaging lens is able to control ghosting occurring between the last lens surface and the imaging element and ghosting caused by light reflected by the lens surface nearest the object, without sacrifice to the compact-size of the optical system or high optical performance.

Abstract: The present invention is directed to an infrared lens that ensures sufficient quantity of light incident on light receiving elements so as to produce a clear infrared picture. The infrared lens comprises a first or leading lens unit of positive refractivity closer to an object, and a trailing lens unit. The trailing lens unit consists of at least a second group of lens pieces located closer to an imaging plane than the first lens unit, and a third group of lens pieces located closer to the imaging plane than the second group of lens pieces. The trailing lens unit is displaced in any direction perpendicular to the optical axis for compensating for image vibration.

Abstract: The present invention is directed to an infrared zoom lens that consists merely of optical components of germanium so as to implement an optical system that is capable of reducing variation in brightness during varying a magnification rate and is quite bright and that facilitates compensating for aberration, especially spherical aberration that is generally hard to do, thereby producing a clear and vivid image. The infrared zoom lens comprises first to fourth groups of lens pieces arranged in series from the foremost position closest to the object; each of the lens groups having all the lens pieces made of germanium, and at least one of the lens groups consisting simply of a single lens piece.

Abstract: The present invention is directed to an infrared zoom lens that has one or more of its lens pieces made of chalcogenide tractable in processing such as press-molding, grinding, and the like, so as to facilitate compensating for spherical aberration that is generally hard to do, thereby producing a clear and vivid image. The infrared zoom lens has first to fourth lens elements arranged in series from the foremost position closest to the object; each of the first to fourth lens elements being of a single lens piece, and at least one of the first to fourth elements is made of chalcogenide.

Abstract: An imaging lens includes, sequentially from an object side, a first lens (L11) configured by a negative meniscus lens disposed with the convex surface on the object side; a second lens (L12) configured by a positive biconvex lens; a negative third lens (L13); and a fourth lens group (L14) configured by a positive meniscus lens disposed with the convex surface on the image plane IMG side. By satisfying given conditions, the imaging lens is able to control ghosting occurring between the last lens surface and the imaging element and ghosting caused by light reflected by the lens surface nearest the object, without sacrifice to the compact-size of the optical system or high optical performance.

Abstract: A laser (10) provided with a discharge activation power supply (11) supplied with power from a 3-phase AC power line, the discharge activation power supply (11) provided inside it with three first capacitors (12a, 12b, and 12c), the laser (10) including an external ground fault protection device comprising a voltage measuring unit using the first capacitors (12a, 12b, and 12c) to measure voltages between the phases of the 3-phase AC power line and the ground and a power breaking unit (18) comparing the values of voltages measured by the voltage measuring unit and a predetermined threshold and breaking the supply of power from the 3-phase AC power line to the power supply (11) when the value of a voltage exceeds the threshold.

Abstract: A discharge excitation type gas laser oscillator has a discharge excitation unit for exciting a laser gas by discharge in a discharge tube to generate induced emission of laser light, a high-frequency power supply unit for supplying power to the discharge tube, and a controller unit for controlling output current of the high-frequency power supply unit.

Abstract: A gas laser oscillator (1), which generates a laser beam by exciting laser gas in discharge tubes (7) with a laser power supply (4) and detecting an abnormality thereof, includes a storage unit (12) for storing the relationship between the output command and the DC current of the laser power supply (4) during the normal operation of the oscillator (1), an output command generating unit (13) for generating an output command corresponding to the peak current value in the relationship between the output command and the DC current, a current detection unit (19) for detecting the current during the operation of the laser power supply (4) based on the output command in the standby operation mode of the gas laser oscillator (1), and an abnormality judging unit (15) for judging that the discharge load of the gas laser oscillator (1) has an abnormality based on the detection current detected by the current detection unit (19) and the peak value of the current in the relationship between the output command and the DC c

Abstract: A startup method capable of easily and inexpensively activating a laser oscillator by limiting an output current of a high-frequency power supply, without using a particular element or a complicated system, even when the laser oscillator is activated in a low-temperature environment, and a gas laser unit having such a function. According to the normal pressure control, the laser gas is gradually increased from pressure p1 to pressure p2. However, in the invention, when DC current reaches a certain threshold at time t3, a feedback control of the laser gas is executed after time t3 such that the DC current does not exceed the threshold. In this case, the laser gas pressure is controlled so as to increase to pressure p2? which is smaller than pressure p2.

Abstract: A laser (10) provided with a discharge activation power supply (11) supplied with power from a 3-phase AC power line, the discharge activation power supply (11) provided inside it with three first capacitors (12a, 12b, and 12c), the laser (10) including an external ground fault protection device comprising a voltage measuring unit using the first capacitors (12a, 12b, and 12c) to measure voltages between the phases of the 3-phase AC power line and the ground and a power breaking unit (18) comparing the values of voltages measured by the voltage measuring unit and a predetermined threshold and breaking the supply of power from the 3-phase AC power line to the power supply (11) when the value of a voltage exceeds the threshold.

Abstract: A high-frequency discharge excited gas laser oscillator receiving power from a laser power supply controlled by a pulse command, the high-frequency discharge excited gas laser oscillator provided with a power detecting section for detecting supply power from the laser power supply to a discharge tube and a pulse command control section positioned at an upstream side of the laser power supply, comparing an allowable upper limit value of supply power found from a relationship between a discharge tube temperature and supply power and an actual supply power detected by the power detecting section, stopping the pulse command value to the discharge tube when the supply power is higher than the allowable upper limit value, and setting a pulse command value based on the allowable upper limit value.

Abstract: A discharge excitation type gas laser oscillator has a discharge excitation unit for exciting a laser gas by discharge in a discharge tube to generate induced emission of laser light, a high-frequency power supply unit for supplying power to the discharge tube, and a controller unit for controlling output current of the high-frequency power supply unit.

Abstract: A laser cutting apparatus capable of properly cutting a workpiece having a large thickness with a laser beam. The laser cutting apparatus includes a gas laser oscillator; and an optical system including a collective lens and transmitting and collecting a laser beam generated in the gas laser oscillator to irradiate a workpiece with the laser beam. An index M2 for evaluating a beam quality of the laser beam emerging from the optical system, with which the workpiece is irradiated, is in a range of 2.8 to 4.

Abstract: A laser apparatus (100) for performing the laser machining operation by condensing the laser light output from a laser oscillator (3) is disclosed. A laser output value calculation unit calculates a laser output value (L1) based on a command value (L0) issued to a laser oscillator (2). A temperature change estimating unit (31) estimates the temperature change or the temperature (Te) of specified component element(s) (7a, 7b) of the laser apparatus based on the elapsed time (t) and the laser output value calculated by the laser output value calculation unit. An adjusting unit (32) adjusts the conditions for controlling the laser or the conditions for laser machining based on the temperature change or the temperature of the specified component element estimated by the temperature change estimating unit. A stable laser machining operation is performed without a temperature sensor. The laser output value (L1) may be measured by a laser power sensor (5).

Abstract: A laser control method for controlling a laser beam irradiated, onto a target object to be processed, during execution of a laser processing program, the method including: providing a processing condition table describing a plurality of different feed velocities, in association with a processing condition of the laser beam corresponding to individual feed velocities; detecting an actual feed velocity of the laser beam that is relative processing velocity of the laser beam relative to the target object while a processing is performed along a processing path instructed by the laser processing program; and determining the processing condition of the laser beam corresponding to the actual feed velocity based on the processing condition table.

Abstract: A high-frequency discharge excited gas laser oscillator receiving power from a laser power supply controlled by a pulse command, the high-frequency discharge excited gas laser oscillator provided with a power detecting section for detecting supply power from the laser power supply to a discharge tube and a pulse command control section positioned at an upstream side of the laser power supply, comparing an allowable upper limit value of supply power found from a relationship between a discharge tube temperature and supply power and an actual supply power detected by the power detecting section, stopping the pulse command value to the discharge tube when the supply power is higher than the allowable upper limit value, and setting a pulse command value based on the allowable upper limit value.

Abstract: A method of making a metallic shell for a spark plug. The metallic shell includes a multi-stepped through hole, an intermediate tubular portion, a tip end side tubular portion and a base end side tubular portion. The through hole includes a large diameter hole section, an intermediate diameter hole section and a small diameter hole section. The method includes the steps of cutting a metal pipe that is used as a starting material to a predetermined length and thereby preparing a pipe-shaped blank, and subjecting the blank to a deformation process and thereby forming the blank into the metallic shell. A spark plug and a method of making the same are also disclosed.

Abstract: A gas laser oscillator of easy maintenance which is capable of switching a beam mode at high speed. Electric discharge sections in which gas medium is flown are formed in an optical resonating space in an electric discharge tube between a rear mirror and an output mirror. Electrodes are connected to electric discharge power sources (alternating current or direct current power sources). Coils are wound around the electric discharge tube at the respective electric discharge sections and excited by coil excitation circuits. Directions and intensities of the excitation currents from the coil excitation circuits are controlled by a controller. Regions in which the electric discharge currents flow between the electrodes in the respective electric discharge sections are varied by magnetic fields generated by the coils in accordance with the directions and intensities of the excitation currents of the coils, to thereby control the beam mode.