Matsushita Electric Works, Ltd.

Miki Kotani

Shin Ukegawa

Atsunori Okada

Shigeaki Wada

Shingo Higashisaka

Hirofumi Konishi

Toshiaki Nakamura

Toshifumi Tanaka

Takashi Kambara

Shinichi Aoki

Taku Sumitomo

Osamu Kuramitu

An improved ballast for a discharge lamp includes a DC&#x2014;DC converter which receives an input DC voltage from a voltage source to provide a pre-starting voltage to make the lamp ready for being ignited or started. The DC&#x2014;DC converter has a switching element which is driven to turn on and off for generating the pre-starting voltage. A start-accelerating means in included in the ballast in order to vary at least one of the switching frequency and the on-period of the switching element based upon the monitored input DC voltage in a direction of accelerating the increase of the output DC voltage to the pre-starting voltage until the output DC voltage reaches the pre-starting voltage.

Discharge lamp ballast with DC-DC converter

A ballast for a discharge lamp includes a DC-DC converter which provides a regulated DC output so as to start and keep operating the lamp. A controller is included to give a closed-loop control for regulating the DC output based upon a monitored DC output. The controller also provides an open-loop control which interrupts the closed-loop control for a limited period immediately after the initiation of the lamp discharge in order to supplement a sufficient lamp current which would not expected with the closed-loop control, thereby successfully complementing the lamp start and proceeding to the stable lamp operation.

Ballast for a discharge lamp

An electrodeless discharge lamp includes a single type auxiliary electrode for preliminary discharging, disposed on or adjacent to outer peripheral wall of lamp tube at a position for being electrostatically coupled to interior space of the tube, and supplied with a power from a second high frequency power source other than a first high frequency power source supplying a high frequency power to a main induction coil on the tube, whereby the lamp is made to attain an excellent startability without requiring any large size high frequency power source.

Electrodeless discharge lamp utilizing induced electric field generated

An electrodeless discharge lamp includes a discharge gas sealed in a lamp tube. The discharge gas includes a halide of rare earth metal. An auxiliary electrode is disposed on or adjacent to an outer periphery wall of the lamp tube such that the auxiliary electrode is capacitively coupled to an interior space of the lamp tube. A main induction coil is wound around the lamp tube and receives power from a first high frequency power source. The auxiliary electrode receives power from a second high frequency power source. In operation, the electrodeless discharge lamp attains smooth lighting upon starting or restarting.

Electrodeless discharge lamp

Electrodeless discharge lamp having a concave recess and foil electrode

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Osaka, Japan

Miki Kotani