Hitachi, Ltd.

Yoji Arai

Seiichi Murayama

Makoto Yasuda

Tsune Miyashita

Shinji Mayama

Hideaki Koizumi

Konosuke Oishi

Masataka Koga

Kazunori Kinoshita

Kenichi Kawasumi

Fuzio Yamada

A high-pressure discharge lamp operating circuit performs a low-frequency AC operating at an early stage of operating and thereafter performs a high-frequency AC operation or DC operation during the steady-state of lamp operation. This circuit comprises a circuit for effecting a transition from the low-frequency AC operation to the high-frequency AC operation or DC operation either at the time which is a predetermined time period after the ignition of discharge before the high-pressure discharge lamp reaches the steady-state of operation, or after having detected at least one of predetermined lamp characteristics, thereby providing a stabilized light output.

High-pressure discharge lamp operating circuit

A discharge lamp comprising an inner arc tube and an outer tube enclosing the inner tube. The outer tube is filled with neon at a pressure of 0.1 atm or more, or a gas mixture of neon in 80 pressure percent or more and breakdown suppressing gas.

Discharge lamp with neon gas in outer tube

A high pressure discharge lamp in which discharge between a pair of main electrodes in an arc tube of the discharge lamp is sustained by a D.C. or high frequency current. The circuit comprises discharge mode controller for controlling the discharge such that mainly a low-frequency discharge is produced between the main electrodes at least within a predetermined time from initiation of the discharge within the arc tube, and subsequently transferred to the D.C. or high-frequency discharge.

A spectral source comprises a lamp containing an anode and a cathode in an inert gas. The cathode has a hollow portion therein, and a opening at its side wall. The anode is positioned to face the opening of the cathode. The anode and cathode are different in shape and connected to a high-frequency discharge power source. A magnetic field is arranged in perpendicular to the direction of the axial center of the opening.

Spectral source, particularly for atomic absorption spectrometry

A spectral source comprises a lamp containing an anode and a cathode in an inert gas. The anode and cathode are different in shape and connected to a high-frequency power source to produce a high-frequency discharge between the anode and cathode to cause both sputtering of the cathode and excitation of a radiation having the spectrum according to the material sputtered from the cathode. The application of solely high-frequency power prevents adherence of the sputtered material to the interior walls of the lamp bulb thereby allowing a reduction of the dimensions of the lamp bulb, prolongating the life time of the lamp and increasing the stability and intensity of the radiation. A magnetic field may be applied to the radiation for Zeeman modulation. Due to the relatively small dimensions of the lamp bulb, relatively small and inexpensive magnets may be used.

An anode and a cathode are disposed in an opposing relation in a tubing in which an inactive gas is enclosed to form a discharge lamp by which an atomic spectrum is emitted. The cathode contains atomic spectrum emitting elements also serving to form the material of cathode. The discharge lamp is supplied with a high frequency power from a high frequency source and simultaneously with a direct current power from a direct current source. This causes the direct current discharge and high frequency discharge to be effected between a pair of electrodes in a superimposed manner. The atoms sputtered by the direct current are efficiently excited by the application of the high frequency with the result that atomic spectra with high brightness are obtained.

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Katsuta, Japan

Yoji Arai