Abstract: A CO2 laser beam 12 is converted into a beam of uniform intensity at the position of a phase matching element 15 by an intensity converting element 14 and the phase matching element 15. Then, the uniform intensity beam irradiates a mask 17 containing an aperture variable in size via a variable-magnification projecting optical system 16. At the time of irradiation, the laser beam at the position of the phase matching element 15 is projected onto the mask 17 at a magnification factor most suited to the size of the aperture formed in the mask 17. Further, the pattern of the mask 17 is projected onto a workpiece 19. Thus, a uniform intensity distribution of the laser beam is obtained on the workpiece and high quality laser processing becomes possible.

Abstract: A microwave powered gas laser apparatus contains a gas medium, and a device for exciting the gas medium to a high energy state by a plurality of microwaves. Directions of vibrations of electric fields of the microwaves are different from each other. There may be provided a device for making the microwaves into standing waves respectively, and a device for exposing the gas medium to antinodes of electric fields of the standing waves.

Abstract: A laser processing apparatus includes a plurality of optical fibers formed into a bundle which is shaped such as to efficiently divide a laser beam into a plurality of split beams and transmit the split beams to respective converging lenses to be focused to have a high energy density when incident on respective workpieces. The optical fibers are shaped such as to each have a sufficiently large value of minimum radius of curvature to ensure that a small angle of divergence is maintained for each of the beams emitted from the fibers, thereby ensuring that the converging lenses can be small and inexpensive.

Abstract: A discharge-pumped gas laser, typically a discharge-pumped excimer laser, includes a main discharge circuit for producing an electric discharge in a laser gas to excite the laser gas for laser emission. The main discharge circuit comprises a first electric circuit having a thyratron, a charging circuit including a charging capacitor for storing an electric energy to operate the thyratron, and a discharging circuit including a pair of main discharge electrodes and a peaking capacitor for storing an electric energy to cause a main discharge in the laser gas between the main discharge electrodes. The laser gas is preionized by preionizers having a plurality of preionizing electrodes which produce an electric discharge to preionize the laser gas.

Abstract: A discharge-pumped gas laser has a pressure container filled with a laser gas under pressure and a pair of elongate main discharge electrodes. The main discharge electrodes are disposed in the pressure container in confronting relationship to each other for producing an electric discharge in the laser gas in a main discharge region defined therebetween to excite the laser gas for laser emission. The laser gas is circulated to flow through the main discharge region in a direction perpendicular to the main discharge electrodes. The laser gas in the main discharge region is preionized by an UV preionizer disposed either upstream or downstream of the main discharge region with respect to the direction of flow of the laser beam. The pressure container houses a baffle partition for controlling the laser gas to flow past one of the main discharge electrodes and the preionizer while blocking the laser gas from directly flowing to the other of the main discharge electrodes and the preionizer.

Abstract: An exposure system includes a pulse light source emitting light in response to a trigger signal and giving a predetermined exposure light quantity by a plurality of times of light emission. A reticle has an alignment mark and a light exposure pattern. A projection lens contractedly projects the pattern of the reticle. A wafer has an alignment mark to be located. The wafer is exposed to a projection of the pattern. A wafer stage is movable and carries the wafer. A laser interferometer measures a position of the wafer stage. An alignment device serves to detect a condition of an alignment of the wafer with respect to the reticle in an exposure position.

Abstract: A laser apparatus comprises an optical resonator including first and second mirrors, and laser medium. An wavelength selection element is provided in the resonator for narrowing band-width. A polarizing conversion element for changing ratio of S to P components and polarizing beam splitter are provided for amplifying laser beam to output after wavelength selection and for reducing light load of the wavelength selection element. The polarizing conversion element is provided in the resonator light path. In another embodiment, the polarizing conversion element is provided in a branch light path formed by a second polarizing conversion element and a third mirror, where the second polarizing conversion element reflects and transmits P component at a given ratio and reflects S component. The wavelength selection element comprises a Fabry-Perot etalon, grating, or prism. The polarizing conversion element comprises a quarter-wave plate or a phase retarder mirror.

Abstract: A laser apparatus comprises an optical resonator including first and second mirrors, and lasing medium. An wavelength selection element is provided in the resonator for narrowing band-width. A polarizing conversion element for changing ratio of S to P components and polarizing beam splitter are provided for amplifying laser beam to output after wavelength selection and for reducing light load of the wavelength selection element. The polarizing conversion element is provided in the resonator light path. In another embodiment, the polarizing conversion element is provided in a branch light path formed by a second polarizing conversion element and a third mirror, where the second polarizing conversion element reflects and transmits P component at a given ratio and reflects S component. The wavelength selection element comprises a Fabry-Perot etalon, grating, or prism. The polarizing conversion element comprises a quarter-wave plate or a phase retarder mirror.

Abstract: Pulses of an ultrasonic wave beam are emitted into a body at a predetermined repetition period. Echo pulses of the ultrasonic wave beam are received via a plurality of different channels. Each of the received pulses is converted simultaneously into corresponding electric signals of the respective channels. A time-dependent change in a variation between the electric signals of the respective channels is derived. A component of a speed of moving matter within the body in a predetermined direction is calculated on the basis of the derived time-dependent change. The moving matter causes the echo pulses. The predetermined direction is perpendicular to a direction of travel of the ultrasonic wave beam pulses.

Abstract: The present invention relates to an ultrasonic examination apparatus which transmits ultrasonic waves into a body to be examined and receives the echo signals therefrom for examination of the inside of the body. The ultrasonic examination apparatus measures acoustic characteristics such as nonlinear parameter within the body using the fact that the characteristic of the reception ultrasonic wave from the inside of the body is varied in accordance with variation of the characteristics within the body. The ultrasonic examination apparatus has first and second ultrasonic transducers for transmitting first ultrasonic pulse and second ultrasonic pulse, respectively. The frequency of the second ultrasonic pulse from the second ultrasonic transducer is higher than that of the first ultrasonic transducer. The first and second ultrasonic pulses are superimposed and transmitted into the body.

Abstract: In a magnetic head of perpendicular magnetization type having main and sub magnetic poles arranged at both sides of a recording medium, a nonmagnetic supporter holding a high permeability magnetic thin layer of the main magnetic pole is formed by a polycrystalline sintered body substantially composed of titanium carbide and alumina. This polycrystalline sintered product well matches with a recording medium having a cobalt-chromium alloy layer so that the recording medium does not wear for a long time of use, and therefore, so that the contact surface of the main magnetic pole is hardly damaged. The same sintered body may also be used for the sub magnetic pole arranged to be in contact with the recording medium. Some structural improvements are also provided so that undesirable influence due to an adhesive layer adjacent to the magnetic thin layer is removed. One or more additional thin layers may be provided for reducing crosstalk between adjacent tracks.

Abstract: In a magnetic head of perpendicular magnetization type having main and sub magnetic poles arranged at both sides of a recording medium, a nonmagnetic supporter holding a high permeability magnetic thin layer of the main magnetic pole is formed by a polycrystalline sintered body substantially composed of titanium carbide and alumina. This polycrystalline sintered product well matches with a recording medium having a cobalt-chromium alloy layer so that the recording medium does not wear for a long time of use, and therefore, so that the contact surface of the main magnetic pole is hardly damaged. The same sintered body may also be used for the sub magnetic pole arranged to be in contact with the recording medium. Some structural improvements are also provided so that undesirable influence due to an adhesive layer adjacent to the magnetic thin layer is removed. One or more additional thin layers may be provided for reducing crosstalk between adjacent tracks.

Abstract: In a magnetic head for perpendicular magnetization recording of a main magnetic pole exited type, a high permeability magnetic thin layer is held at its top portion by nonmagnetic supporter and the thin layer is closed by a first high permeability block. The thus constructed main magnetic pole is surrounded by a second high permeability block, and a third high permeability block is located in facing relation to the main magnetic pole and second high permeability material. This magnetic head has high recording and reproducing efficiency and well-shielded from external magnetic field. Some structural improvements are also provided so that leakage of magnetic flux, disconnection and short circuit of a coil are avoided.

Abstract: In a conventional surface acoustic wave ring filter, a time-compensation element in the form of a thin strip is additionally provided for either retarding or accelerating one of the surface acoustic waves which transmit along different transmission lines, thereby the phases of two surface acoustic waves received by a single output converter included in the filter are matched with each other resulting in the improvement in the output signal characteristics.

Abstract: A ghost signal erasing system for television receivers in which a variable delay element utilizing the propagation of an elastic surface wave is used. The variable delay element includes a piezoelectric substrate, a plurality of first interdigitated electrode pairs formed on the substrate and a plurality of second interdigitated electrode pairs also formed on the substrate. An elastic surface wave produced by applying a video i-f signal to the first interdigitated electrode pairs is propagated along the surface of the piezoelectric substrate and taken up at the second interdigitated electrode pairs as a delayed a-c signal. By switching the first and second interdigitated electrode pairs to change the combination thereof, various delay times are obtained.