Koninklijke Philips Corporation N.v.

Michael Haacke

Pieter Postma

Ralf Muckel

Lukas Kuepper

Klaus Schoeller

Lars Dabringhausen

Thomas Luce

Wilfried Emunds

Francis Martin Jozef Deprez

Nicasius G T Van Gennip

Petrus J M Fransen

Martin Stroesser

Georg Haselhorst

Ulrich Hechtfischer

Manfred Westemeyer

Xaver Riederer

Norbert Lesch

Paul Hellwig

Lukas Küpper

Juergen Schoeneich

Shin'ichi Honma

Marc F R Janssen

Bernd Prokesch

Jürgen Schoeneich

Heinz Helmut Huedepohl

Jurgen Adriaensen

Nicasius Gerardus Van Gennip

The invention describes a gas-discharge lamp () comprising a vessel (), which vessel () is partially coated with at least one longitudinal stripe (S, S') arranged on the surface of the vessel () below a horizontal plane (P) through a longitudinal axis (X) through the centre of the lamp () such that, on each side of the lamp, an angle (&#x3b2;, &#x3b2;) subtended at the lamp centre by the horizontal plane (P) and an upper edge () of the longitudinal stripe (S, S&#x2032;) on that side of the lamp comprises at least 10&#xb0;, more preferably at least 13&#xb0;, most preferably at least 15&#xb0;. The invention also describes a reflector () for a lamp (), comprising a reflective interior surface realized to deflect light (L, L, L, L) originating from the lamp () outward to give a specific beam profile () with a bright/dark cut-off line () and a shoulder (), and wherein the lamp (), in particular a lamp () according to any of claimsto, is positioned horizontally in the reflector (), and wherein the reflective interior surface comprises at least one beam-shaping region (A,B) realised to deflect a portion (L, L) of the light (L, L, L, L), emitted from the lamp () between 7.5&#xb0; and 15&#xb0; below a horizontal plane (P), at a specific region (A,B) within the beam profile (). The invention further describes a lighting assembly () comprising such a reflector () and a lamp (), in particular a lamp () according to the invention.

Gas-discharge lamp

A lighting assembly () includes an electronic driver circuit () and a discharge lamp (). The discharge lamp () is driven with a steady-state average power of 20-30 W. It includes a discharge vessel () of a maximum inner dimension ID of less than 3 mm with two electrodes (). A discharge vessel filling comprises a rare gas and a metal halide composition provided in an amount per volume of the discharge vessel () of less than 13.2 &#x3bc;g/&#x3bc;l. Electrical energy is supplied as an alternating current Iwhere pulses (-) are superimposed. The pulses occur in a time interval of 20% of a half-cycle time before or after a polarity change of the alternating current I. During the pulses the current Ireaches the current value of at least 1.2 times the RMS value of the current I.

High efficiency lighting assembly

A discharge lamp comprises a discharge vesseldefining a sealed inner discharge spacewith two electrodes. A filling consists of a rare gas and a metal halide composition and is free of mercury. The discharge vesselcomprises outer grooveswhere the electrodesare embedded, arranged at a groove distance Ra between them. The discharge vesselfurther comprises an inner diameter ID. In operation of the lamp, an arc discharge is formed between the electrodes and the metal halide composition is partly evaporated. After operation of the lamp, the metal halide composition forms a film on the inner wall of the discharge vessel. This film has a surface area Ameasured in mm. The metal halide composition is provided in such an amount within the discharge space, that a matching quotient Q, calculated as Q=Ra&#xd7;ID/Ahas a value of 2 or more, such that a high color temperature is achieved.

Discharge lamp with high color temperature

The invention describes a method of driving a gas-discharge lamp () according to conditions in a specific region (R) of the lamp (), which gas-discharge lamp () comprises a burner () in which a first electrode () and a second electrode () are arranged on either side of a discharge gap, which lamp () is realised such that the position (PCs) of a coldest spot during an AC mode of operation is in the vicinity of the first electrode (), which method comprises the steps of initially driving the lamp () in the AC mode of operation; monitoring an environment variable of the lamp (), which environment variable is indicative of conditions in a specific region (R) of the lamp (); switching to a temporary DC mode of operation at a DC power value on the basis of the monitored environment variable, whereby the first electrode () is allocated as the anode; and driving the lamp () in the DC mode of operation until the monitored environment variable has returned to an intermediate environment variable threshold value (T). The invention also describes a gas-discharge lamp and a driver for a gas-discharge lamp.

Method of driving a gas-discharge lamp

The invention describes a gas-discharge lamp () comprising a vessel (), which vessel is partially coated with an essentially rectangular stripe (S) arranged circumferentially on a surface of the vessel, and wherein a first long side () of the stripe is situated close to a base () of the lamp, and the width (w) of the stripe is such that a first angle (&#x3b1;) subtended at a lamp center between a radius (r) and a point on the first long side () of the stripe comprises at most 55&#xb0;, and a second angle (&#x3b1;) subtended at the lamp center between the radius and a point on a second long side () of the stripe comprises at most 50&#xb0;. The invention also describes a reflector for a lamp, comprising a reflective interior surface realized to deflect light originating from the lamp outward to give a specific beam profile with a bright/dark cutoff line and a shoulder, and wherein the lamp, in particular a lamp as described above, is positioned horizontally in the reflector, and wherein the reflective interior surface comprises at least one beam-shaping region realized to deflect a portion of the light emitted from the lamp between 7.5&#xb0; and 15&#xb0; below a horizontal plane, at a specific region within the beam profile.

In order to achieve a discharge lamp suited to operate under reduced nominal power of e.g. 20-30 W, a lamp is proposed with two electrodes () arranged at a distance in a discharge vessel () for generating an arc discharge. The discharge vessel () has a filling with a substantially free of mercury and comprises a metal halide and a rare gas. The lamp () further comprises an outer bulb () arranged around the discharge vessel at a distance (d). The outer bulb () is sealed and has a gas filling of a thermal conductivity (&#x3bb;). The inner diameter (d) of the discharge vessel is preferably in a range from 2-2.7 mm. The wall thickness (w) is in a range from 1.4-2 mm. A heat transition coefficient (&#x3bb;/d) is calculated as thermal conductivity (&#x3bb;) at 800&#xb0; C. of the outer bulb filling divided by the distance (d). The so-defined heattransition coefficient is below 150 W/(mK).

Low power discharge lamp with high efficacy

A high pressure gas discharge lamp has electrodes that project into a discharge space surrounded by a discharge wall. The discharge space has a filling of rare gas and metal halides. The metal halide composition comprises halides of sodium and scandium with a mass ratio of halides of Sodium and Scandium of 0.9-1.5. In order to provide a lamp that can be easily manufactured and is well suited for operation at reduced power, the discharge vessel wall is of externally and internally cylindrical shape. The lamp may be manufactured by providing a cylindrical tube of quartz material, heating the tube at two distant portions and forming grooves there, inserting two electrodes into the tube and heating and pinching the tube at both ends to seal the discharge space. Manufacture is carried out without a bulb forming step such that the discharge space remains in externally and internally cylindrical shape.

Discharge lamp with improved discharge vessel

A high-pressure gas discharge lamp has a sealed discharge vessel with an inner discharge space. Two electrodes project into the discharge space. The filling in the discharge space includes metal halides and a rare gas. The filling is free of Hg and Th and includes halides in an amount of 7.1-11.4 &#x3bc;g/mmof the volume of the discharge space. The halides includes at least NaI and ScI, provided in such amounts that a ratio of the masses of NaI to ScIis 1.2-1.6.

Thorium-free discharge lamp with reduced halides and increased relative amount of Sc

A high pressure gas discharge lamp includes a discharge vessel with electrodes that project into a discharge space of a volume of 12-20 mm. The discharge space has a filling of rare gas and a metal halide composition which is free of mercury. The metal halide composition includes at least halides of Sodium and Scandium with a mass ratio of halides of Sodium and Scandium of 0.9-1.5. The lamp further includes an outer enclosure provided around the discharge vessel. The outer enclosure is sealed and filled with a gas at a pressure below 1 bar. The lamp has an efficiency equal to or greater than 90 Im/W in a steady state operation at an electrical power of 25 W.

High efficiency discharge lamp

A mercury-free high-pressure gas discharge lamp (HID [high intensity discharge] lamp) is described which is provided for use in automotive technology. To achieve improved lamp characteristics, in particular a substantially equal luminous efficacy in comparison with lamps of the same power and a mercury-free gas filling, as well as a highest possible burning voltage, the discharge vessel () is provided in its wall regions () which are lowermost in the operational position with a coating () which reflects at least a portion of the infrared radiation generated during operation, such that the temperature of the coldest spots, and in particular of the light-generating substances collected there, is raised, with the result that the light-generating substances can enter the gas phase in sufficient quantities also without mercury, and in particular with the use of a metal halide as a voltage-gradient generator.

Mercury-free-high-pressure gas discharge lamp

A high-pressure gas discharge lamp includes at least a lamp tube and two electrodes. The two electrodes are each attached to the lamp tube by a sealed area and, outside the sealed area, each electrode has a perpendicular minimum distance, with respect to its longitudinal axis, from the lamp tube.

High-pressure gas discharge lamp

A high-intensity discharge (HID) lamp comprising an inner bulb () with a discharge vessel () and an outer bulb (), especially for application in an automotive headlight unit is disclosed. A lamp design is proposed by which high thermal stresses and increased quartz temperatures during run-up and steady state operation of the lamp are avoided so that the light output and the lifetime of the lamp is improved. This is substantially achieved by a positioning of the inner and the outer bulb () such that a longitudinal axis of the inner bulb () is displaced in the operating position of the lamp above a longitudinal axis of the outer bulb () so that the distance between the discharge vessel () and the outer bulb () at the top side of the lamp is decreased and the distance between both at the bottom side is correspondingly increased.

High-intensity discharge lamp

An electrode includes thorium as a minor component for a high-pressure discharge lamp, where the electrode rod is free of thorium/thorium oxide, or comprises thorium/thorium oxide, as a minor constituent. A covering member made of refractory metal, free of thorium/thorium oxide, is circumference coated on the electrode rod in the vicinity of the discharge side tip. The entire surface of the electrode rod is completely coated over the range where the covering member extends. The electrode rod tip of the electrode rod is not, or at least partly, coated with the covering member. The part of the electrode tip, which is not coated by the covering member, is free of thorium/thorium oxide.

Thorium-free electrode with improved color stability

A mercury-free gas discharge lamp suitable in particular for motor vehicles has an enhanced discharge arc diffuseness. The lamp according includes an inner vessel and/or outer bulb with a structured arrangement or pattern such that the discharge arc diffuseness of the lamp is increased, such as by 0.01 mm to 1.5 mm.

Growing community of inventors

Aachen, Germany

Michael Haacke