Hitachi, Ltd.

Hitachi Engineering Co., Ltd.

Hiroyuki Sugawara

Toshiharu Shirakura

Kouji Kuwabara

Kouji Sasaki

Satoshi Takemori

Yukio Kawakubo

Yukio Kurosawa

Tuneyoshi Oohashi

Akira Wada

Toshimichi Kichikawa

Nobuo Abe

Motoo Yamaguchi

Takashi Namekawa

Hiroshi Arita

Keiichi Kuniya

Hideo Arakawa

Shigeo Shiono

Kiyoji Iwashita

Minoru Suzuki

Takao Miyashita

Shunji Tokuyama

Yoshiyuki Kubota

Koukichi Ouhata

Hideki Yamai

Takeshi Yamamura

Kooji Kuwabara

Kouzi Suzuki

Norio Ikemoto

Humio Shibata

The present invention relates to a laser oscillator, especially to a laser oscillator suitable for ultrafine manufacturing such as an apparatus for manufacturing of a semiconductor wherein the laser oscillator is provided with constant directivity chronically, although the directivity is not so fine, for avoiding a blurred image spatially and chronically in order to obtain a stable mask in the ultrafine manufacturing. The laser oscillator includes apparatus for enabling at least one of selection of the directivity of parallel light from a resonator between a whole reflector and a laser medium; an optical system for stopping oscillation of the laser medium before a laser beam, which is generated at the resonator, becomes a single mode and for eliminating the laser beam having poor directivity; prevention of the laser medium from re-entry of unnecessary natural emitting light which is generated in the laser medium; and providing a value of a diameter of an aperture of the optical system for maintaining directivity so as to make an order number of the transverse mode high.

Laser oscillator, laser resonator, and apparatus for manufacturing of

A metal vapor laser has a discharge tube with electrodes at opposite ends. A power source is electronically connected to the electrodes and generates a discharge in a discharge region within the discharge tube. The discharge generates laser light which emerges from the tube via windows. In order to cool the apparatus, the discharge tube is surrounded by a cooling jacket in the form of a hollow cooling vessel. A liquid flows in the cooling vessel and removes heat. The space between the cooling vessel and the discharge tube is evacuated. The cooling vessel is conductive and, since it is connected between one of the electrodes and the power supply, its inner and outer walls provide two potential paths for return current. The fact that the inner and outer walls have different diameters means that the inductance of the return paths is large. Therefore, the outer wall has a gap in it filled with insulating material. This forms a break in the conductive path from the electrode to the power source through the outer wall, and so reduces the inductance of the return path. Other geometries are also possible in which all but the innermost path are broken by insulating material.

Metal vapor laser apparatus

In a pulse power supply circuit, first and second charging capacitors are connected in series with a discharge device. First and second gas-filled control switching elements, connected in parallel with each other, are respectively connected in series with the first and second charging capacitors. First and second pulse power sources are respectively connected in parallel with the first and second control switching elements and also respectively connected in series with the first and second charging capacitors so as to charge the capacitors alternately. A control circuit controls the first and second control switching elements so that the switching elements alternately and repeatedly at substantially equal time intervals.

Pulse power supply circuit

A vacuum switch apparatus has an electrically insulating vacuum enclosure which is evacuated to a vacuum degree of 2.times.10.sup.-2 Torr or less. One set of anode and cathode electrodes is arranged in the vacuum enclosure, having capacity which permits the flow of a discharge current of at least 1 KA therebetween and being operable to switch the discharge current at least 10.sup.6 shots. A high voltage power supply applies a high voltage of at least 20 KV across the anode and cathode electrodes. An electron beam irradiation unit irradiates an electron beam on the anode electrode through the cathode electrode. A control electrode is arranged between the beam irradiation unit and the cathode electrode, for controlling passage and interception of the electron beam. A control voltage power supply applies a control voltage to the control electrode. An electromagnetic coil is arranged at least exteriorly of the vacuum enclosure, for generating electromagnetic force which prevents the electron beam, emitted from the electron beam irradiation unit and reaching the anode electrode through the control and cathode electrodes, from being scattered.

Vacuum switch apparatus

A metallic vapor laser apparatus includes a cylindrical discharge tube (31) having an internal space (2), a heat-insulating material (6) encompassing the periphery of the discharge tube (31), and two electrodes (3a) and (3b) having a cylindrical portion coaxial with the discharge tube (31) and disposed at both ends of the discharge tube (31). The internal space (2) are filled with a gas containing the vapor of copper as a laser medium for effecting laser oscillation by the excitation of the filler gas and the discharge. A gas inlet (40) from introducing a buffer gas (G) into the inside is formed at one of the outside position of the two electrodes (3a) and (3b) in the axial direction and gas exhaust ports (33a) for exhausting the buffer gas (G) to the outside are formed in the proximity of both ends of the heat-insulating material (6) so that flow paths in which the buffer gas flows from the side of the internal space (2) to the side of the heat-insulating material are formed between the discharge tube (31) and the electrodes (3a) and (3b).

Metallic vapor laser apparatus

A laser device equipped with a high-voltage pulse generator wherein the pulse generator supplies an electric energy from a dc power source in an on-off form of a supply voltage to a tank circuit through a transformer, with the switching on and off of the supply voltage being effected in synchronism with the resonance period of the tank circuit. The tank circuit stores the supplied electric energy as a resonance condition so that when the electric energy stored in the tank circuit reaches a predetermined value, a saturable reactor connected between the laser device and the tank circuit becomes saturated and the electric energy in the tank circuit is discharged to the laser device.

Laser device with high-voltage pulse generator, high-voltage pulse

In a gas laser device according to this invention, a gas inlet having an electrode protrudes within each of expanded portions protruding on the side, where the gas inlet is disposed, of the principal portion of the discharge tube. Gas medium ejected from the gas inlet in the principal portion of a discharge tube collides with the inner surface of the principal portion of a discharge tube, while forming a flame extending along the ejected gas medium from the electrode and is divided into two partial flows. One of them flows along the wall of the expanded portion; collides with the gas inlet; and is divided further into two partial flows. Therefore it does not collide with the gas medium within the gas inlet. Consequently the gas medium and the flame fluctuate hardly and are stabilized. In this way it is possible to stabilize the laser output.

Gas laser device

A discharge tube structure of a gas laser generator has end common vessels at its both end sections and an intermediate common vessel at its intermediate section. The end common vessels and intermediate common vessel are connected through the first and second cooling ducts to a centrifugal blower, which is provided at its center the first communicating port communicating with the first cooling duct and at least two second communicating ports communicating with the second cooling ducts opposed to each other with respect to the first communicating port. The simplified second cooling ducts allows the mixture gas to be supplied smoothly to the intermediate common vessel, thereby increasing the laser output.

Gas laser generator

A gas laser device has an anode and a cathode arranged oppositely in a discharge tube. The cathode comprises a plurality of cathode members each having a predetermined discharge effective cathode surface and each being electrically isolated from others. A switching circuit selects the cathode member(s) used for a continuous wave oscillation and the cathode member(s) used for a pulsed oscillation. The total area of the discharge effective cathode surface(s) of the cathode member(s) used for the pulsed oscillation is selected to be smaller than, preferably 1/3 to 1/2 of that of the discharge effective cathode surface(s) of the cathode member(s) used for the continuous wave oscillation.

A gas laser has an electrode of improved construction. The electrode, for example a cathode, comprises an inner cathode and at least an outer cathode spaced from the inner cathode and disposed on the side thereof away from to an anode. Each of the cathodes has a central hole from which glow discharge is formed, and the outer cathode further has a plurality of through-holes around the central hole. A gas medium flowing in a discharge tube passes through the central hole of the inner cathode via the central hole and through-holes of the outer cathode. The gas medium forcedly enters the glow discharge from the inner cathode thereby to cause it expand and a part of the gas medium having passed through the through-holes of the outer cathode squeeze the glow discharge from the outer cathode so that the glow discharge can enter the glow discharge from the inner cathode. Therefore, the current density of the glow discharge in the discharge tube is made information.

Gas laser device with plural electrode members on the upper gas flow side

A cathode-ray tube has in a neck section of a hermetically sealed, evacuated envelope an electron-gun mount assembly in which of a cathode for emitting an electron beam, a first grid electrode section for forming a crossover point and for accelerating the electron beam and a second grid electrode section for focusing the electron beam are mounted on a plurality of insulative supporting bars. A conductive member is provided on an outer surface portion of the neck section, an inner surface portion thereof, and/or an outer surface portion of the supporting bars which surround a portion of the electron-gun mount assembly including the first grid electrode section but excepting the second grid electrode section.

Cathode-ray tube

The invention is to provide a gas laser in which a discharge tube of a double-tube construction comprising a inner tube and an outer tube of a relatively large diameter is employed, a tubular discharge space filled with a gas mixture is formed between the inner tube and the outer tube, a gas mixture cooling passage is formed within the discharge space, and a pair of mirror groups are disposed at both ends of the discharge space, each mirror group comprising a plurality of mirrors arranged in the circumferential direction. The respective mirrors are arranged in such a manner that a laser beam is reflected by the mirrors to go and return in the discharge space several times and each path of the laser beam between the corresponding two mirrors obliquely intersects the central axis of the discharge space. Thus, it is possible to obtain a laser beam in single mode with a single discharge tube without the need of enlarging a length of the tube and also to reduce a pressure loss of the gas mixture within the discharge space.

Gas laser

Method of and apparatus for measuring laser beam

A gas laser oscillation apparatus wherein, in order to prevent a center axis of a reflecting mirror included in a laser resonator from deviating from an optical axis of the laser resonator due to the deformation of a mirror supporting frame caused by a vacuum force applied to a laser tube, the reflecting mirror is fixed to a mirror holding plate, which is attached to the mirror supporting frame with fasteners such as bolts and nuts.

Mirror supporting frame for gas laser oscillation apparatus

A vacuum interrupter of parallel magnetic field electrode type comprising a pair of separatable arc electrodes disposed within a vacuum vessel, with each being provided on its back side with a conductive rod extending outwardly of the vacuum vessel. Coil electrodes are electrically connected between the associated arc electrode and rod for applying parallel magnetic fields to arc, and slits are formed in the arc electrodes for suppressing eddy currents of the arc electrodes resulting from the parallel fields. A reinforcement member of an electric conductivity higher than a main surface portion of the arc electrode is provided on the back side of the arc electrode opposite to said main surface portion so that the resulting arc current flows uniformly through the reinforcement member so that a higher interruption efficiency can be obtained for the vacuum interrupter.

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Hitachi, Japan

Hiroyuki Sugawara