Toshiba Lighting & Technology Corporation

Kabushiki Kaisha Toshiba

Kenji Araki

Keiichi Shimizu

Hiroki Sasaki

Akira Ito

Ichiro Yokozeki

Kazuiki Uchida

Akihiro Yonezawa

Mitsuhiro Matsuda

Fumio Hirano

Youichirou Mitsuyuki

This invention suppresses the occurrence of interference in a very short period to prevent device destruction. An inverter circuit of this invention includes a crystal oscillator, which oscillates at a fixed frequency, a load-status detector, which receives a voltage and current to be applied to a load including an inductive or capacitive component and detects the status of the load, a voltage-controlled oscillator, which oscillates at a frequency corresponding to the load status detected by the load-status detector, and a switch, which selects the output of the crystal oscillator or the output of the voltage-controlled oscillator and supplies the selected output to the load. An electrodeless discharge lamp lighting device according to this invention uses an inverter circuit having the above structure.

Inverter having frequency changing function

A low pressure discharge lamp apparatus has a low pressure discharge lamp with an arc tube. The arc tube has a first end and a second end, each with electrodes which define a discharge space therebetween. A mercury/rare gas is sealed in the arc tube. The low pressure discharge lamp apparatus further has a lighting circuit apparatus for lighting the lamp by supplying a current with a polarity reversed for each half cycle to electrodes in the first and second ends of the arc tube. The lighting circuit apparatus supplies, to the lamp, a current whose waveform has a flat peak for each half cycle and a maximum current value of the current is restricted to less than a level in which the excitation of mercury atoms is saturated.

Low pressure discharge lamp apparatus

A high pressure sodium lamp includes a light permeable ceramic bulb wherein a pair of electrodes are oppositely arranged. One of the electrodes is inserted into one end of a metal tube, the other end of which is pinched. The center line average surface roughness of the inner surface of the metal tube is held below 2 .mu.m for preventing melted sodium-mercury amalgam condensed on the inner surface of the other end of the metal tube from moving along the inner surface of the metal tube by capillary action toward the one end thereof.

High pressure sodium lamp substantially preventing movement of melted

Growing community of inventors

Yokosuka, Japan

Kenji Araki