JPH0613028A - High voltage discharge lamp - Google Patents

Abstract

PURPOSE: To provide a high-pressure discharge lamp having a metal halide filler by reducing flickers in comparison with the prior art so as to achieve excellent arc and combustion characteristics having optical and electric data which are stable until the lamp reaches the life. CONSTITUTION: In a high-pressure discharge lamp having a narrowed discharge tube and a metal halide filler, an electrode 4 comprises a linear shaft member 17 and a filament member 18 oriented toward a discharge side and having turns out of contact with each other. A solid head member 19 which is formed into a globular shape toward at least a discharge arc and at least whose the half of diameter is intruded into the filament member 18 is fused at the end of the filament member 18.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a discharge tube containing a filling of mercury, a metal halide and at least one noble gas in which two electrodes are hermetically sealed via a sealing foil. The electrodes are composed of a linear shaft member facing the narrowed portion and a filament member facing the discharge portion, the shaft member and the filament member are composed of wire pieces having a constant diameter, and the axis of the filament member is A high-voltage discharge lamp for electric power of 400 W or less, which extends towards the discharge arc, the filament element is composed of at least 1.5 turns, where adjacent turns do not touch each other.

[0002]

PRIOR ART German Federal Patent No. 3232207
Such metal halide high pressure discharge lamps are known from the specification for general lighting. Lamps of this type usually have good combustion and ignition characteristics, and can also have various flicker that fluctuates strongly with the passage of time.

In this case, flicker means all fluctuations in luminance from periodic flicker to aperiodic flicker. This brightness variation is combined into one value, that is, a flicker coefficient. According to conventional studies, there is a direct proportional relationship between the flicker coefficient and the DC component of the lamp current. Technically, flicker is caused by insufficient electrode temperature due to the flight of the arc to the various protrusions.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to reduce flicker compared to the prior art, which results in good ignition characteristics and combustion with stable optical and electrical data until the lamp life is reached. It is an object to provide a high pressure discharge lamp having a metal halide filling such that characteristics can be obtained.

[0005]

According to the present invention, such a problem is solved by fusing a solid head member having a substantially spherical shape toward at least the discharge arc at the discharge side end of the filament member. Will be solved.

Advantageous embodiments of the invention are described in the subclaims.

[0007]

By forming the tip of the head member of the electrode in a substantially hemispherical shape, it is possible to eliminate or reduce the arc flight to the protrusion. The smoother the surface of the head member, the better the flight of the discharge arc is prevented. By "substantially hemispherical" is meant that the tip of the head member includes a shape that is slightly deformed from a hemisphere to an ellipsoidal or elliptical shape. By fusing the head member to the final turn on the discharge side of the filament member, the mass of the head member is increased, thereby providing a large heat capacity. As a result, the surface of the head member is not significantly cooled during the interruption of the current. Therefore, the electrode head has a constant temperature during lighting and corrosion of the electrode is reduced, especially when having a tin-containing fill.

Filament members do not contact one another
It is advantageous to have 5 to 2.5 turns. The heat outflow towards the constriction can cause cooling of the surface of the electrode head, but such heat outflow is thereby largely prevented.

[0009]

The present invention will be described in detail with reference to the drawings.

FIG. 1 shows the construction of a 70 W high-pressure discharge lamp 1 according to the invention with a quartz glass discharge tube 2 having one end squeezed, which discharge tube 2 is likewise squeezed at one end. It is surrounded airtight by the outer tube 3 made of quartz glass. The electrodes 4, 5 shown schematically are hermetically sealed in the discharge vessel 2 via molybdenum sealing foils 6, 7 and lead wires 8, 9, sealing foils 10, 11 of the outer tube 3 and here. Is an electric terminal pin 12 of a ceramic base 14 of type G12 via another short lead wire (not shown),
It is connected to 13. Further, a getter material 16 is floatingly fixed on the metal plate piece through the wire piece in the narrowed portion 15 of the discharge tube 2. The discharge vessel contains, as fillings, in addition to mercury and noble gases, metal iodides and bromides of sodium, tin, thallium, indium and lithium.

FIG. 2 shows the electrode 4 of the high pressure discharge lamp shown in FIG. An electrode 4 consisting of a single piece of tungsten wire with a diameter of 0.4 mm (the construction of the second electrode is similar to that of this electrode 4) consists of a shaft member 17 and a filament member 18. The shaft member 17 is a molybdenum sealing foil 6
It is airtightly sealed inside the narrowing portion 15 via. The filament member 18 is bent 90 ° with respect to the shaft member 17 and has two turns. These 2 turns have an outer diameter of 1.2
mm has a mutual spacing of 0.1 mm. In the final turn on the discharge side, a solid head member 19 in the shape of a sphere having a diameter of 1.0 mm is fused. All parts of the electrode are composed of undoped tungsten.

The 150 W high pressure discharge lamp 20 shown in FIG. 3 with a metal halide fill consists of a quartz glass discharge tube 21 with narrowed ends, which in turn has narrowed ends. It is surrounded by a squeezed outer tube 22. The electrodes 23, 24 shown schematically are hermetically sealed in the discharge vessel 21 by foils 25, 26, and lead wires 27, 28, sealing foils 29, 30 of the outer tube 22.
And another ceramic lead (R
7s) 31 and 32 are connected to electrical terminals. In the narrowed portion of the discharge tube 21, a getter material 33 mounted on a metal plate piece via a wire piece is fixed in a floating manner. The ends 34 and 35 of the discharge tube 21 are provided with a heat reflection coating. As a filling material, the discharge tube 21 contains metal iodide and metal bromide of sodium, tin, thallium, indium and lithium in addition to mercury and a rare gas.

FIG. 4 shows the electrodes 23, 24 incorporated in the high pressure discharge lamp 20 of FIG. These electrodes 23,
24 has a linear shaft member 36 and a filament member 37, both of which are made from a single piece of tungsten wire having a diameter of 0.5 mm. The shaft member 36 is sealed in the narrowed portions 38 of the discharge tube via the molybdenum sealing foils 25 and 26. The filament member 37 has an outer diameter of 1.4 mm
Has 2.5 turns and the individual turns have a mutual spacing of 0.15 mm. A sphere 39 having a diameter of 1.2 mm is fused to the discharge side end of the filament member. All parts of the electrode are composed of undoped tungsten. However, it is also possible to use a doped tungsten material for this example and for the electrode of FIG.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a high pressure discharge lamp according to the present invention having a fixed outer tube.

FIG. 2 is a schematic view showing electrodes of the high pressure discharge lamp according to the present invention shown in FIG.

FIG. 3 is a schematic view showing a high pressure discharge lamp according to the present invention having a fixed outer tube.

FIG. 4 is a schematic view showing electrodes of the high pressure discharge lamp according to the present invention shown in FIG.

[Explanation of symbols]

 1 70 W High-pressure discharge lamp 2 Discharge tube 3 Outer tube 4, 5 Electrode 6, 7 Sealing foil 8, 9 Lead wire 10, 11 Sealing foil 12, 13 Terminal pin 14 Ceramic base 15 Squeezing part 16 Getter material 17 Shaft member 18 Filament member 19 Head member 20 150W high pressure discharge lamp 21 Discharge tube 22 Outer tube 23, 24 Electrode 25, 26 Foil 27, 28 Lead wire 29, 30 Sealing foil 31, 32 Ceramic base 33 Getter material 34, 35 End 36 Member 37 Filament member 38 Squeezing part 39 Ball

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Axel Bunk Germany 1000 Berlin 13 Eich Engrund 18 Ar (72) Inventor Jürgenscheid German Federal Republic 1000 Berlin 22 Zete Wake 29

Claims (3)

[Claims] 1. A discharge tube (2; 21) comprises a filling consisting of mercury, a metal halide and at least one noble gas, and a sealing foil (6, 7; 25, 26) in the discharge tube.
The two electrodes (4, 5; 23, 24) are hermetically sealed via the electrodes, and the electrodes (4, 5; 23, 24) are connected to the linear shaft member (17; 36) facing the constricted portion. The filament member (18; 37) facing the discharge part, and its shaft member (17; 36) and the filament member (18; 3).
7) is composed of a piece of wire having a constant diameter, the axis of the filament element (18; 37) extending towards the discharge arc, the filament element (18; 37) comprising at least 1.5 turns, In a high pressure discharge lamp for electric power of 400 W or less in which adjacent turns do not come into contact with each other, a solid head member having a substantially spherical shape at least toward the discharge arc at the discharge side end of the filament member (18; 37) ( 19; 39), which are fused together. 2. High-pressure discharge lamp according to claim 1, characterized in that at least half the diameter of the head member (19; 39) projects into the filament member (18; 37). 3. The filament member (18; 37) is 1.
The high pressure discharge lamp according to claim 1, wherein the high pressure discharge lamp has 5 to a maximum of 2.5 turns.