Matsushita Electric Industrial Co., Ltd.

Tatsuhiro Yabuki

Shiro Iida

Noriyuki Uchida

Kenji Itaya

Kenji Nakano

Takashi Ueda

Hiroki Kitagawa

Osamu Zaitsu

Junichi Takahashi

Makoto Okuda

Jiro Kajino

Mitsuo Utsumi

Takayuki Iwasaki

An arc tube is formed by turning a glass tube at a substantially middle thereof and winding the glass tube from the middle to its both ends around an axis to form a double spiral, and sealing electrodes at both ends of the glass tube. The spiral pitch of a spiral part in a vicinity of one of the ends and an adjacent spiral part in the direction of the axis is set larger than the spiral pitch of other adjacent spiral parts, to widen a gap between the one end and the adjacent spiral part.

Arc tube with shortened total length, manufacturing method for arc tube, and low-pressure mercury lamp

Disclosed is a compact self-ballasted fluorescent lamp with higher luminous efficiency than conventional lamps and improved luminous flux rising characteristics at lamp startup equivalent to those of general fluorescent lamps. The compact self-ballasted fluorescent lamp () includes an arc tube () formed by a bent glass tube () covered with a globe (). The glass tube () has a turning part substantially in the middle between its both ends, a first spiral part starting from one end and wound around an axis toward the turning part, and a second spiral part starting from the turning part and wound around the axis toward the other end. The arc tube () has mercury enclosed therein in a single form. The glass tube () has a substantially circular-shaped cross section and an inner diameter of 7.4 mm. The turning part is connected to the globe () via a heat-conductive member ().

Fluorescent lamp and manufacturing method for arc tube

A mandrel has a main body having a substantially-cone-shape. The main body has, on its circumferential surface, a spiral-shaped groove at which the glass tube to be wound is held. The groove, in cross section, has a contact range in which the glass tube's circumferential surface is in contact. One end of the contact range corresponds to a circumference part of the glass tube in wound state which is closest to the axis of the main body of the mandrel, a part of the groove that extends from the circumference part towards the apex of the main body is parallel to the axis of the mandrel, and the pitch of the groove in the axial direction of the mandrel is formed smaller than the outer diameter of the glass tube. The glass tube wound on the mandrel is easily removed from the main body by lowering the mandrel. In the arc tube formed in such a way, any two glass tube portions, which are adjacent to each other in the axial direction of the arc tube, overlap with each other.

Small arc tube, low-pressure mercury lamp, lighting apparatus, mandrel for forming the arc tube, and production method of the arc tube

The manufacturing method comprises: a softening step of softening a straight glass tube in a heating furnace; a moving and placing step of moving the softened glass tube so that the glass tube is placed on the top of the mandrel; and a winding step of winding the glass tube placed on the top of the mandrel around the periphery of the mandrel. The mandrel is disposed beneath the glass tube starting to get soft, and the glass tube being soft is perpendicularly lowered in order to be placed on the top of the mandrel. In the winding step, the winding speed Vr at which the glass tube is wound around the mandrel is higher than the moving speed Vs at which chuck units holding the ends of the glass tube move toward the mandrel.

Manufacturing methods of double-spiral arc tubes

A diffuser is formed on an inner surface of a globe included in a compact self-ballasted fluorescent lamp, and a diffuse transmittance of the diffuser &#x3c4; is set at 95%. When designing dimensions of the compact self-ballasted fluorescent lamp, at the same time, a ratio D/Pis set at 0.8 or greater. Here, Pis a helical pitch of an arc tube having a helical configuration, and Dis a half of a difference between a helix diameter of the arc tube and a maximum outside diameter of the globe.

Compact self-ballasted fluorescent lamp, fluorescent lamp and helical glass tube

Disclosed is a discharge lamp with enhanced vertical illuminance and accordingly improved light distribution characteristics that is easy to manufacture and suitable for mass production. For a discharge lamp in which a discharge path with a double helix configuration is formed or a discharge lamp in which a plurality of U-shaped tubes are placed on an arc tube holder to form a single tortuous discharge path, a width of a turning part is specified so as to narrow spaces formed in an arc tube top part, or swelling parts are provided in a vicinity of the arc tube top part so as to narrow the spaces.

Discharge lamp with improved light distribution characteristics

A tape cassette to be mounted on a magnetic recording/reproducing apparatus. A magnetic tape is extended in front of an opening formed at a front part of a housing. The housing is provided with a front cover for covering the tape. The tape is exposed by an upward rotation of the front cover. The front cover is upwardly rotated when a slider, which is slidably attached to the housing, is slid rearward with respect to the housing. The slider, which is in engagement with an engaging member, is slid by relative movement of the engaging member and the housing. The slider is locked to the housing by a locking member, which unlocks the slider when the engaging member is engaged with the slider.

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Takatsuki, Japan

Tatsuhiro Yabuki