Hitachi, Ltd.

Etsuo Urataki

Hiromitsu Matsuno

Hiroshi Ohno

Churyo Kodama

Taisuke Hirota

Masaroshi Kodama

Yoshio Takano

Mitsuru Nakagawa

Masayoshi Kodama

Yoshinobu Tomita

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 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

A mount having a flared portion is so located that it is coaxial with a straight glass tube having an unconstricted end part and that an end face of the flared portion lies slightly inwards with respect to an end face of the glass tube. Subsequently, an outer surface of the end part of the glass tube is uniformly heated, whereby the flared portion and the end part of the glass tube are melted and stuck to each other. At this time, a surface temperature of the whole glass tube except the melted and stuck portion is maintained at or above 40.degree. C. As a result, a fluorescent lamp having good lamp characteristics is fabricated by the use of the inexpensive glass tube.

Method for fabricating fluorescent lamp

A fluorescent lamp with reflective layer of the present invention has a first phosphor layer and a second phosphor layer which are partially laminated. The first phosphor layer is formed on the whole inner surface of the glass tube, and the second phosphor layer is formed on the first phosphor layer at a predetermined angle of reflection along the axial direction of the glass tube. The laminated portions of the first and second phosphor layers substantially form a reflective layer, and the other portions form a transmitting layer.

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Tokyo, Japan

Etsuo Urataki