Matsushita Electronics Corporation

Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Panasonic Photo & Lighting Co., Ltd.

Haruo Yamazaki

Hirofumi Yamashita

Toshihiro Terada

Hidezoh Akutsu

Shinji Kihara

Yoshiro Ogata

Takashi Ikeda

Takashi Maniwa

Shigeru Ido

Yusuke Mori

Hiroshi Sakurai

Akiko Nakanishi

Masanobu Murakami

Takio Okamoto

Kazuhiro Kumada

Akio Kitada

Taizou Ono

Tomokazu Matsuura

Hidezo Akutsu

Toshiyuki Namura

Minoru Myojo

Naoki Saito

Makoto Yokozeki

Yoshiaki Watarai

Masayuki Yamaguchi

Koji Takasaki

The orientation of fluorescent lamps is detected in a manufacturing method for a direct backlight unit that alternates orientations of adjacent fluorescent lamps. In a preparation step of the manufacturing method for the backlight unit of the present invention, a plurality of fluorescent lamps are prepared. In each of the fluorescent lamps, a length (a) from a first sealed portion of a glass bulb () to a non-phosphor layer () area is shorter than a length (a) from a second sealed portion to a non-phosphor layer () area (a&#x3c;a). In a detection step, the difference between the lengths is detected with use of a sensor. In an installation step, the fluorescent lamps are arranged with use of the detection results so that the first and second ends alternate on a same side of a housing.

Method for manufacturing direct backlight unit, fluorescent lamp and backlight unit

A low-pressure discharge lamp () is provided that includes a glass tube () having an inner diameter in a range of 1 to 5 mm and a pair of electrodes () disposed at end portions in the glass tube (). The pair of electrodes () contain at least one transition metal selected from transition metals of Groups IV to VI. Mercury and a rare gas containing argon and neon are sealed in an inner portion of the glass tube (). A relationship between a cathode glow discharge density J and a composition index &#x3b1; of the sealed rare gas of the low-pressure discharge lamp () satisfies the following expression&#x3b1;&#x2266;/()&#x2266;1.5&#x3b1;(where S represents an effective discharge surface area (mm) of an electrode, I represents a RMS lamp current (mA), P represents a pressure (kPa) of a sealed rare gas, and &#x3b1; represents a composition index of a sealed rare gas that is a constant expressed by &#x3b1;=(90.5A+3.4N)&#xd7;10when a total of a composition ratio A of argon and a composition ratio N of neon is expressed by A+N=1).

Low-pressure discharge lamp and back light device using the same

A cold-cathode fluorescent lamp including a glass bulb and a pair of electrodes which are cylindrical and respectively inserted in two ends of the glass bulb. Two end portions of the glass bulb are substantially circular in transverse cross section, the two end portions respectively corresponding to the inserted pair of electrodes in length. At least part of a middle portion of the glass bulb is flat in transverse cross section, the middle portion corresponding to a space in the glass bulb between the pair of electrodes.

Cold-cathode fluorescent lamp and backlight unit

Low-pressure discharge lamp and back light device using same

The present invention has an object to provide a cold-cathode fluorescent lamp which can suppress sputtering caused by electric discharge and reduce consumption of mercury so as to achieve a longer lifetime even if a lamp current is large and a lighting tube has a small diameter. The cold-cathode fluorescent lamp according to the present invention is characterized in that a distance between the inner surface of the lighting tube and the outer surface of a cylindrical electrode is set such that electric discharge develops mainly on the inner surface of the cylindrical electrode. When the lighting tube has an inside diameter Dof 1 to 6 mm and the maximum lamp current is 5 mA or more, an outside diameter Dof the cylinder electrode is preferably set at D&#x2212;0.4 [mm]&#x2266;D&#x3c;D

Cold-cathode fluorescent lamp

The present invention has an object to provide a cold-cathode discharge lamp which can suppress sputtering on a lead-in wire and reduce consumption of mercury so as to achieve a longer lifetime without increasing an amount of applied mercury. The cold-cathode discharge lamp of the present invention is characterized in that a lead-in wire connected to a cylindrical electrode in a lighting tube is made of a material same as a material that forms the cylindrical electrode. It is possible to suppress concentration negative glow discharge shifted to the lead-in wire and to allow the electrode to be covered with even negative glow discharge. Thus, it is possible to reduce mercury consumed by excessive sputtering on the outer surface of the internal lead-in wire and to achieve a longer lifetime of the cold-cathode discharge lamp.

Cold-cathode discharge lamp and lamp device having reduced sputtering on internal lead-in wire

The present invention has an object to provide a cold-cathode fluorescent lamp which can suppress sputtering caused by electric discharge and reduce consumption of mercury so as to achieve a longer lifetime even if a lamp current is large and a lighting tube has a small diameter. The cold-cathode fluorescent lamp according to the present invention is characterized in that a distance between the inner surface of the lighting tube and the outer surface of a cylindrical electrode is set such that electric discharge develops mainly on the inner surface of the cylindrical electrode. When the lighting tube has an inside diameter D of 1 to 6 mm and the maximum lamp current is 5 mA or more, an outside diameter D of the cylinder electrode is preferably set at D &minus;0.4 &lsqb;mm&rsqb;&lE;D D

A discharge lamp or an electrodeless discharge lamp including a discharge gas filled inside a bulb, an electrode part present inside the bulb for emitting thermoelectrons into the discharge gas, and a cesium compound placed in a position other than the electrode part inside the bulb. According to this configuration, this discharge lamp has a short starting delay time even at a low temperature including room temperature, without using any starting auxiliary light source or a radioactive material. The cesium compound is contained on the surface of a metal mesh which is fixed via a supporting arm in a position avoiding the electrode part inside the bulb. It is preferable that the cesium oxide is in contact with the discharge space. In this way, starting property can be improved without using any starting auxiliary light source or a radioactive material. The electrodeless discharge lamp has the cesium compound at an optional position in the discharge space.

Discharge lamp having cesium compound

In a fluorescent lamp device, a discharge tube is made by arranging electrodes at the ends of a glass tube, sealing mercury and a rare gas into the glass tube and coating the inner surface of the glass tube with a phosphor, and an amalgam forming material is disposed close to one or the other of the ends of the discharge tube. This fluorescent lamp is operated with a d.c. current using as the anode the electrode arranged on the discharge tube end side where the amalgam forming material is located.

Fluorescent lamp device

In a fluorescent lamp of the type in which a lamp envelope comprises an outer bulb having generally a spherical or a partially spherical or a cylindrical configuration and an inner bulb inserted into the outer bulb in predetermined nested relationship; either of the inner surface of the outer bulb or the outer surface of the inner bulb is formed with a groove which defines a zig-zag discharge path between the outer and inner bulbs; a phosphor is formed at least over the wall surfaces of the groove; electrodes are disposed at the ends, respectively, of the discharge path and a uv (ultraviolet) radiation-emitting discharge gas consisting of mercury vapor and a rare gas or a rare gas mixture is filled in the discharge path, both the open end portions of the outer and inner bulbs are flared radially outwardly and inwardly respectively, or either of the open end portion of the outer or inner bulb is flared radially outwardly or inwardly so that glass frit can be filled into the annular space defined between the open end portions of the outer and inner bulbs both or either of which is flared. When glass frit is heated and then solidified, not only the open ends of the outer and inner bulbs can be gas-tightly sealed together but also lead-wires which also support the electrodes at the ends of the discharge path are also gas-tightly sealed.

Fluorescent lamp and process for fabricating the same

A high-pressure sodium lamp in which the ends of an arc tube which is made of transparent single-crystal alumina and which contains sodium are sealed with feed-throughs each having an electrode extended from the inner end thereof. Each feed-through is directly sealed to the inner wall surface of each end of the arc tube. In addition, each feed-through is formed with an enlarged-diameter portion which is directly sealed to the inner wall surface at each end of the arc tube and a reduced-diameter portion which is spaced apart from the inner wall surface at each end of the arc tube.

High-pressure sodium lamp

Each of the electrodes at the ends of an arc tube filled with a buffer gas, metal and sodium comprises an electrode core, an electrode coil wound around the core, an electron-emitting means disposed in the annular space between the electrode core and electrode coil and a shielding means disposed in said annular space in such a way that the electron-emitting means is shielded from exposure to the discharge space in the arc tube. The ratio h/d is determined such that 0.8.ltoreq.h/d.ltoreq.5.4, where h is the length in mm of the portion of the electrode core extended beyond the inner end of the shielding means or the innermost coil of the electrode coil; and d is the diameter in mm of the electrode core. The arc spots can be held to remain on the end faces of the electrode cores during lamp operation so that variations in electrical and optical characteristics can be almost eliminated.

A high pressure sodium vapor discharge lamp,

High pressure sodium vapor discharge lamp

A high pressure sodium vapor discharge lamp comprises an alumina tube envelope containing therein sodium, inert starting gas, buffer gas source of mercury or cadmium and discharge electrodes sealed in the envelope, inner diameter d (in mm) of said tube envelope and an average potential gradient E in volt/cm having the relation

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Moriyama, Japan

Haruo Yamazaki