Nec Corporation

Nec Microwave Tube, Ltd.

Kazuhisa Nishida

Tatsuya Uchikawa

Takashi Kanamoto

Toshimoto Makino

Yasushi Aoki

Yasuhiro Akiyama

A high-pressure discharge lamp has a lamp bulb of silica glass encapsulating mercury, an inactive gas, and a mixed halogen gas containing at least two halogen gases, and at least a pair of electrodes disposed in the lamp bulb in confronting relation to each other. The type and content of a primary halogen gas whose content is the greatest in the mixed halogen gas are determined based on a bulb wall load.

High-pressure discharge lamp

A high-pressure discharge lamp is produced using tungsten wire that is wound as a double coiled winding around an electrode metal rod, leaving a tip end thereof, and the double coiled winding is machined into a melted tip end by a YAG laser beam, with the remaining double coiled winding used as a coil. The tip end of the metal rod is machined into a nipple on the distal end of the melted tip. The melted tip has a diameter Dand a length Lthe nipple has a proximal end having a diameter Dand a length Land the coil and the melted tip end (including the nipple) have a volume Vand the melted tip end (including the nipple) has a volume V, when the electrode assembly is machined to satisfy at least one of the conditions 0.15&#x2266;D/D0.3, 0.2&#x2266;L/L0.4, and 0.2&#x2266;V/V0.4.

A high pressure discharge lamp includes a quartz glass bulb, a conductive element which is sealed at a sealing portion of the bulb, and a pair of electrodes. Each electrode is disposed in the quartz glass bulb so as to be opposite the other and connected to the conductive element. A part of each electrode is sealed with the quartz glass bulb at the sealing portion so as to generate a contacting portion formed by the part of each electrode and the bulb. The maximum length, L, of the contacting portion is defined as: L(mm)&#x2266;200/(P&#xd7;D); and the minimum length, L, of the contacting portion is defined as: L(mm)&#x2267;0.8/(D&#xd7;&#x3c0;) or L(mm)&#x2267;0.7 whichever is longer, where D is the diameter (mm) of the electrode and P is the power (W) supplied to the electrode.

High pressure discharge lamp and method for sealing a bulb thereof

A high pressure discharge lamp includes a quartz glass bulb and a pair of electrodes. Each electrode of the pair of electrodes is disposed so as to be opposite the other in the quartz glass bulb. The quartz glass bulb of the high pressure discharge lamp contains at least mercury and a halogen gas which are airtightly sealed in the quartz glass bulb. The partial pressure of oxygen (O) in the quartz glass bulb is about 2.5&#xd7;10Pa or less and the partial pressure of the halogen gas in the quartz glass bulb is in the range between about 1&#xd7;10&#x3bc;mol/mmand 1&#xd7;10&#x3bc;mol/mm. The pair of electrodes contain potassium oxide in the range between about 20 ppm and 40 ppm.

High pressure discharge lamp and method of production therefor

A long-life high-pressure discharge lamp suffers reduced blackening and luminance drop even after it has been turned on over a long period of time, and is arranged to prevent the internal gases from leaking out and also to prevent the lamp bulb from being ruptured. The high-pressure discharge lamp has a pair of confronting electrodes inserted in a lamp bulb which confines therein at least mercury and a halogen gas. The lamp bulb contains oxygen at a partial pressure lower than a partial pressure which can maintain a luminance of 80% after 100 hours of operation and equal to or higher than 1.0&#xd7;10Pa.

The high-pressure discharge lamp of the present invention includes: a discharge chamber that is formed in a silica glass tube, a pair of electrodes that are arranged with ends confronting each other in the discharge chamber; metal foil parts that are superposed and bonded to the other ends of the electrodes, and sealing sections for hermetically sealing the discharge chamber and which are parts for embedding the other ends of the electrodes and the metal foil parts in the glass at the two ends of the silica glass tube. The electrodes and the metal foil parts are embedded in the glass in a state in which metal coils are wrapped around the vicinities of the junctions of the electrodes and metal foil parts. The ends of the metal foil parts on the electrode side are further formed as tapered portions. In addition, the tips of the tapered portions on the electrode side are positioned, with respect to their direction of width, within the width in the radial direction of the electrodes.

High-pressure discharge lamp and method of fabricating same

A high pressure discharge lamp includes a quartz glass bulb, a conductive element which is sealed at a sealing portion of the bulb, and a pair of electrodes. Each electrode is disposed in the quartz glass bulb so as to be opposite the other and connected to the conductive element. A part of each electrode is sealed with the quartz glass bulb at the sealing portion so as to generate a contacting portion formed by the part of each electrode and the bulb. The maximum length, L , of the contacting portion is defined as: L ((mm))&lE;/200/(P&times;D); and the minimum length, L , of the contacting portion is defined as: L ((mm))&gE;0.8/(D &times;&pgr;) or L ((mm))&gE;0.7 whichever is longer, where D is the diameter ((mm)) of the electrode and P is the power (W) supplied to the electrode.

A high pressure discharge lamp includes a quartz glass bulb, a conductive element which is sealed at a sealing portion of the bulb, and a pair of electrodes. Each electrode is disposed in the quartz glass bulb so as to be opposite the other and connected to the conductive element. A part of each electrode is sealed with the quartz glass bulb at the sealing portion so as to generate a contacting portion formed by the part of each electrode and the bulb. The maximum length, L , of the contacting portion is defined as: L (mm)&lE;200/(P&times;D); and the minimum length, L , of the contacting portion is defined as: L (mm)&gE;0.8/(D &times;&pgr;) or L (mm)&gE;0.7 whichever is longer, where D is the diameter (mm) of the electrode and P is the power (W) supplied to the electrode.

A high-pressure discharge lamp is effective to prevent initial blackening on an outer casing thereof, is of a long service life, and can easily be manufactured. A tungsten wire is wound as a double coiled winding around an electrode metal rod, leaving a tip end thereof, and the double coiled winding is machined into a melted tip end by a YAG laser beam, with the remaining double coiled winding used as a coil. The left tip end of the metal rod is machined into a nipple on the distal end of the melted tip end. If it is assumed that the melted tip end has a diameter D and a length L up to its distal end, the nipple has a proximal end having a diameter D and a length L from the proximal end up to the distal end thereof, and the coil and the melted tip end (including the nipple) have a volume V and the melted tip end (including the nipple) has a volume V then the electrode assembly is machined to satisfy at least one of the conditions 0.15&lE;D /D &lE;0.3, 0.2&lE;L /L &lE;0.4, and 0.2&lE;V /V &lE;0.4. The machined electrode assembly is incorporated as an electrode into a lamp bulb.

The high-pressure discharge lamp of the present invention includes: a discharge chamber that is formed in a silica glass tube, a pair of electrodes that are arranged with ends confronting each other in the discharge chamber; metal foil parts that are superposed and bonded to the other ends of the electrodes, and sealing sections for hermetically sealing the discharge chamber and which are parts for embedding the other ends of the electrodes and the metal foil parts in the glass at the two ends of the silica glass tube. The electrodes and the metal foil parts are embedded in the glass in a state in which metal coils are wrapped around the vicinities of the junctions of the electrodes and metal foil parts. The ends of the metal foil parts on the electrode side are further formed as tapered portions.

A high pressure discharge lamp includes a quartz glass bulb having a sealing portion; and a pair of electrodes. Each electrode of the pair of electrodes is disposed so as to be opposite the other in the quartz glass bulb. The quartz glass bulb of the high pressure discharge lamp contains at least mercury and a halogen gas. The partial pressure of oxygen (O) in the quartz glass bulb is about 2.5&times;10 Pa or less and the partial pressure of the halogen gas in the quartz glass bulb is in the range between about 1&times;10 &mgr;mol/mm and 1&times;10 &mgr;mol/mm .

High pressure discharge lamp and method for producing thereof

A high pressure discharge lamp includes a quartz glass bulb having an expanded portion and sealing portions, conductive elements, and a pair of electrodes. The conductive elements are sealed at the sealing portions of the quartz glass bulb. Each electrode is disposed so as to be opposite the other and connected to one conductive element. The lamp is characterized in that Dp (the distance between an end of each electrode) is in the range between 1.0 and 1.6 mm, S (the longest length of the expanded portion in the direction of a discharge path)&equals;e&times;Di (wherein 0.8<e<1.0), Di (the largest inside diameter of the expanded portion transverse to the discharge path)&equals;g&times;Dp (wherein 4<g<8 ), and Do (the largest outside diameter of the expanded portion transverse to the discharge path)<Di&plus;4 mm.

High pressure discharge lamp with reduced bulb thickness

A high pressure discharge lamp includes a quartz glass bulb and a pair of electrodes. Each electrode of the pair of electrodes is disposed so as to be opposite the other in the quartz glass bulb. The quartz glass bulb of the high pressure discharge lamp contains at least mercury and a halogen gas which are airtightly sealed in the quartz glass bulb. The partial pressure of oxygen (O) in the quartz glass bulb is about 2.5&times;10 Pa or less and the partial pressure of the halogen gas in the quartz glass bulb is in the range between about 1&times;10 &mgr;mol/mm and 1&times;10 &mgr;mol/mm . The pair of electrodes contain potassium oxide in the range between about 20 ppm and 40 ppm.

A high pressure discharge lamp includes: a quartz glass bulb having an expanded portion and sealing portions; conductive elements, and a pair of electrodes. The conductive elements are airtightly sealed at the sealing portions of the quartz glass bulb. Each electrode of the pair of electrodes is disposed so as to be opposite the other and each electrode is connected to one of the conductive elements. An angle &thgr; between a tangent along the inner surface of the expanded portion at a position 0.5 mm away from an origin of one of the sealing portions along the length direction of each electrode and the direction of the length of each electrode is at least about 40&deg;.

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Tokyo, Japan

Kazuhisa Nishida