Hitachi, Ltd.

Hiromitsu Matsuno

Tetsuo Ono

Seiichi Murayama

Yoshio Watanabe

Shigeo Mikoshiba

Yasuo Kato

Etsuo Urataki

Soichiro Ogawa

Yasusuke Seki

Churyo Kodama

Atsuo Koyama

Takao Shimizu

Masayoshi Kodama

Masaroshi Kodama

Tsuyoshi Kobayashi

A lighting device for a hot cathode fluorescent lamp used for a back light of a liquid crystal display or the like attempts to prolong the life of a lamp in a lighting device for a low consumption wattage fluorescent lamp. More specifically, the hot cathode fluorescent lamp is started while being pre-heated, and even after starting, a pre-heat current keeps flowing. The pre-heat current value after starting is set to be smaller than that at the time of starting for the purpose of optimizing the hot spot temperature. With employment of the configuration as described above, the lifetime of the hot cathode fluorescent lamp when used as a back light can extend to 10,000 hours or more.

Lighting device for fluorescent lamp

A negative glow discharge lamp device has a discharge container enclosing at least a rare gas, a hot cathode disposed in the discharge container and coated with a thermion radiation matter, and an anode located in a negative glow domain formed between the anode and the hot cathode in the discharge container, a power conversion circuit for driving the lamp device includes a rectifier directly connected at its d.c. output terminals to the hot cathode and the anode respectively for supplying d.c. electric power to the discharge container, and a capacitor ballast connected between a power supply terminal of an a.c. power source and an a.c. input terminal of the rectifier for controlling discharge current in the discharge container.

Negative glow discharge lamp device

A fluorescent lamp has at least a pair of electrodes, at least two circular discharge tubes connected to said electrodes and enclosing rare gas and mercury therein, and a phosphor coating provided on an inside wall of each of said discharge tubes, the two circular discharge tubes being arranged coaxially circularly on one and the same plane, the diameter of each of the discharge tubes being selected to have a value within a range of from 5 mm to 25 mm both inclusive, the luminance on surface of each of the discharge tubes being selected to have a value within a range of from 2.times.10.sup.4 Cd/m.sup.2 to 6.times.10.sup.4 Cd/m.sup.2.

Circular fluorescent lamp

A negative glow discharge lamp of small size comprising a cylindrical discharge container enclosing at least rare gas, a hot cathode disposed in the discharge container and coated with a thermion radiation matter, and an anode disposed in a negative glow domain formed between the anode and the hot cathode in the discharge container. In the discharge lamp, the outer diameter D (mm) of the discharge container is selected to satisfy the relation

Negative glow discharge lamp

Disclosed is a compact fluorescent lamp which comprises an airtight outer bulb filled with a rare gas and mercury; inner tube means provided within the outer bulb, said means having opening to a space of the inside of the outer bulb, and a coating formed onto at least one of an inner surface of said outer bulb and an outer surface of said inner tube means, said coating being so transparent as substantially not to scater visible rays and which consists of at least one material of an oxide and a phosphate. A compact fluorescent lamp mostly in the electric bulb shape of the present invention has been remarkably improved in the so-called lumen output maintenance without lowering of the initial lumen output.

Compact fluorescent lamp

A low-pressure mercury vapor discharge lamp in which a rare gas and mercury are provided in an outer bulb, which in turn contains therein a plurality of bent inner tubes, each having an opening at an end and an electrode at the other end thereof. A starting probe is provided between the openings in the outer bulb. An operating circuit or starter is connected to the electrodes. Further, a starting probe circuit is connected to the starting probe to apply a high voltage to the starting probe at the time of ignition.

Low-pressure mercury vapor discharge lamp

A low-pressure mercury vapor discharge lamp comprising a glass tube in which a metal oxide or phosphate layer and then a phosphor layer are formed on its inner surface, in which during operation of the lamp, the lowest temperature of the wall of the glass tube along its discharge path is kept at 80.degree. C. or above.

Stain resistant fluorescent lamp

A low-pressure mercury vapor discharge lamp comprising an envelope forming a gas-tight closed space and a pair of inner tubes provided in the closed space and having an end thereof sealed at the first end of the outer envelope, the other end thereof being opened into the closed space, and electrodes provided at the sealed end sides in the inner tubes. The temperature of the coldest spot of the envelope is in a range between 45.degree. C. and 65.degree. C. at an ambient temperature of 25.degree. C.

Growing community of inventors

Hachioji, Japan

Hiromitsu Matsuno