DE1639086A1 - Electric discharge lamp with a vessel made of densely sintered aluminum oxide - Google Patents

Description

File: PHN-2385

Registration from H. Pebr. 1968

TeV «Philips ¹ Gfloeilampenfabrieken, Eindhoven / Holland

"Electric discharge lamp with a vessel made of densely sintered aluminum oxide" ο

The invention relates to electric gas discharge lamps with an envelope of the discharge space made of translucent, densely sintered aluminum oxide and on a process to manufacture such a lamp »

The wall of a gas discharge lamp must consist of a material which is resistant to the chemical action of the gas atmosphere in the discharge space at the operating temperature for the entire service life of the lamp. If the temperature is high during operation and the gas atmosphere contains components of an aggressive nature, as is the case, for example, with high-pressure sodium vapor lamps from Pail, in which the temperature during operation is between 700 ^° C. and 1500 ^° C., materials such as normal glass or quartz glass are not more v / finable. This is because they are severely attacked during operation and show considerable discoloration, which affects the light emission. In addition, the attack reduces the mechanical strength of the envelope, which increases the risk of the lamp breaking, in order to curb these difficulties as much as possible areas, it is known to make the envelope of such lamps from translucent

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to produce densely sintered aluminum oxide. This is understood to mean a material which consists of at least 95 % by weight of aluminum oxide and is formed by heating a mixture of essentially aluminum oxide and a temporary binder to a very high temperature, after that which is usual in the ceramic industry Way has been brought into a certain form.

Except for high pressure sodium lamps for use, it is advantageous, also the wrapping of high-pressure mercury vapor discharge lamps and vapor lamps, in particular of high-pressure mercury W containing in Entlodungsraum iodine or iodides, to be made of densely sintered translucent aluminum oxide. This material shows a better resistance to the aggressive influences of the gas atmosphere than quartz glass, which has so far been often used for such lamps.

Only a few metals such as tungsten, molybdenum and niobium come into consideration as materials for the electrodes and the power supply elements to be fastened gas-tight in the casing for these lamps; Hiobium in particular is suitable for use as a power supply element, since its coefficient of expansion matches that of densely sintered aluminum oxide.

The production of gas-tight melt-downs is also possible with suitable ones Choice of metal for the Stromzuführungselemer.te, in particular Niobium, still very difficult. Oies finds especially its cause in the extremely high melting point de ·; Alumina (higher than 1925 C) and in the fact that the alumina has no melting range like glass or quartz glass. That is why there are already a lot of constructions for the gas-tight melt-downs are known.

One of the most common ways to improve meltdown

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is the use of a tubular power supply selementee. Such a tubular Stromzuführungseler.ent namely has a certain flexibility, whereby small differences in the expansion coefficients are more easily compensated. Such a tube is difficult to fix directly in the envelope and is therefore a known construction the tube in a separate processing gas-tight in one; also consists of translucent, densely sintered aluminum oxide earth plug is attached, which plug is again in the cover made of the same material as that of the plug is fastened facetight.

In the case of a rowing construction, instead of one in the casing arranged. A plug made of densely sintered aluminum oxide existing cover is used, the gas roof on the outside is attached to an opening of the envelope.

In another construction, the mnn is also tubular Current .- '. Guide element with a thinner radial Splash a ^ s of larger diameter provided and this splash directly in an opening in the envelope of the discharge lamp attached. Such encapsulation is a matter of course very flexible. A “modification of the meltdown is a construction in which the splash is not in an opening of the Vmhtillunr melted, but on the outside with the— itself is fused.

In the. Most of the constructions described above are used. Connecting glass between the assembling parts of the 3? Irsc ^v r.elzune ·, since one is practical without such a glass

does not have to be able to establish a casdichtp connection. To the glass / of course, taking into account the high temperatures and the aggressive atmosphere that the compounds are exposed to are exposed to both the manufacture and operation of the lamps, high demands are placed on them.

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BATH ORIGINAL

Lamps of the above constructions have proven themselves in the Proven in practice, but due to the particular difficult processing, the percentage of lamps that are used immediately after manufacture must be rejected, very large. The invention aims to improve this.

An electric gas discharge lamp according to the invention contains a sheath of the discharge space consisting of translucent, densely sintered aluminum oxide and at least one power supply element fastened in a gas-tight manner in the casing, which casing has a cylindrical part at the point of the power supply element, and is characterized in that it is in the cylindrical shape Part is made of translucent, densely sintered aluminum oxide firing element, which is sintered gas-tight to the envelope and has an opening in which the power supply element with the help of a connecting glass with a melting point higher than 80O ⁰ C and lower than that of the translucent densely sintered aluminum oxide and of the metal of Stromzufuhrungselement.es gas-tight, and that the lamp is further supported with a against the end of the cylindrical part of the envelope and against the terminating element located therein, through einendem densely-sintered aluminum oxide existing lid is provided with an opening for the power supply element, said cover is higher by a bonding glass having a melting point of 800 ⁰ C and lower than that of the translucent densely sintered aluminum oxide and the metal of the current supply element to the sheath, the closure element and the power supply element is connected in a gas-tight manner.

As explained in the above, constructions are known in which in a tube of translucent, densely-sintered Aluminum oxide a plug to close off the venting space is attached. This plug is in the known execution

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melting

This type of construction is not reliable, mainly due to the fact that the expansion coefficient of the connecting material used is not always the same. As a result, tensions easily occur in the connections, which can cause a crack _e In addition, an edge of connecting material forms in the corner seam between the plug and the casing on the inside **. As a result, not only does discoloration often occur, but the crack in the connecting material often begins at this point, which then spreads further in the material between the plug and the casing of the AbS closing element is sintered to the envelope, all these disadvantages are avoided

The lid, made of densely sintered, translucent aluminum oxide, which according to the invention is connected to the cylindrical part of the envelope and the closing element by means of a connecting glass, ensures that no leakage can occur, in particular not along the power supply element. Because there is also a thin layer of glass between the cover and the casing and between the cover and the cover element, an even more reliable gas-tight connection is obtained. * ser glass edge is yes on the outside of the whole structure, and thus can not be attacked by the aggressive atmosphere eng discharge space ·

The connecting glass, with which the different parts with

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are connected to each other, a melting point must be higher than 800 C have, because lamps according to the invention are often so heavily loaded that their temperature exceeds 700 C ^0. This is particularly the case when a high pressure discharge is generated in the discharge space in an atmosphere which contains at least one alkali metal, mercury and at least one noble gas. In particular, the invention is in so-called high-pressure sodium "'triumdampflampen applicable in which the Alkslimetall sodium and the inert gas xenon.

In lamps according to the invention, as in known lamp constructions, there is at least the power supply element that part which is gas-tight in the closure element and in the cover is arranged, preferably made of the metal niobium

In a particularly advantageous embodiment of an inventive Gas discharge lamp, the cover protrudes from the cylindrical part and is located in between The corner seam of these two parts forms a connecting glass edge · This creates an even more reliable gas-tight seal obtain.

As is the case with low-pressure sodium lamps, the invention Lamps an evacuated or inert gas, for example Argon, filled outer bulb can be used, in which the envelope of the actual discharge vessel is separated. This As with the low-pressure sodium lamps, the outer bulb serves as a thermal insulator. With a particularly advantageous one. Embodiment of a discharge lamp according to the invention, at the power supply element consists of a tube, the other the side facing away from the discharge space is open, is located in the tubular power supply element with a low Pin-shaped support element arranged in it with clearance and firmly connected to the outer bulb · Da the pin-shaped

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Support element with little clearance in the tubular power supply element is arranged, the actual discharge vessel can expand slightly without creating any forces the power supply element are exercised, which lead to the breakage of the seal \ md / or the power supply element could. Ba is the electrical connection between the power supply element and the pin-shaped support member is sometimes insufficient due to the clearance between these two parts is, according to a particular embodiment of a lamp according to the invention, a flexible electrically conductive connection between the power supply element and a pole wire arranged in the outer bulb, for example in a pinch of the same appropriate"

Embodiments of the invention are in the drawings and are described in more detail below, They show:

Pig, Fig. 1 is a view of an embodiment of one according to the invention electric gas discharge lamp showing the general construction »

Pig. 2 shows a detailed illustration of the construction of the gas-tight fastening of the closure element, the cover and of the current supply element j

3 shows a modification of the construction according to FIG. 2; Pig. 4 shows a compilation of a power supply element unn a lid, v / ie these in the process of manufacturing a gas discharge lamp according to the invention is used,

Fig. 5 shows an Anp ^ rat for the production of an inventive Gas discharge lamp and in particular for the production of gas-tight seals,

FIG. 6 shows a modification of the construction according to FIG. 1.

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In Fig. 1, 1 is the envelope of a discharge space 2 in which a gas discharge can be generated in an atmosphere made up of, for example, sodium vapor, mercury vapor and a Edelgasι, for example xenon, is there. The envelope 1 consists made of translucent, densely sintered aluminum oxide. The electrodes 3 are located at the ends of the discharge space 2 and 4, which are constructed in a known manner and contain, inter alia, a tungsten filament. The electrodes 3 and 4 are on current supply elements 5 and 6 attached, made of niobium tubes exist. With 7 and 8 two final elements are indicated, which is also made of translucent, densely sintered aluminite

) consist oxide; they are attached to the casing 1 by sintering. With 9 and 10 two covers are indicated, which are also made of densely sintered, translucent aluminum oxide exist and are attached both to the envelope 1 and to the closure elements 7 and 8. The discharge tube 1 is inside an outer bulb 11 made of, for example, hard glass. This outer bulb has a pinch 12, in which two retaining wires 13 and 14 are attached, which also serve as a power supply for the electrode e 4 or the electrode 3 effective sinde With 15 and 16 two strip-shaped connecting elements are indicated, which the electrodes 3 and 4 with connect the retaining wires 14 and 13, respectively. Around the retaining wire 14 • There is a quartz tube 17 for shielding. With 18 and 19

"two getter rings are indicated that create the vacuum in the outer bulb 11 upheld.

In Pig. 2, the construction of the upper end of the gas discharge tube 1 of FIG. 1 is shown on an enlarged scale. In this figure, corresponding parts have the same reference numerals as in Fig. 1. With the thick black lines 20 is indicated that the closing element 7 made of translucent, densely sintered aluminum oxide in the existing of the same material Enclosure 1 is firmly sintered »With 21 a connection is

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tion glass indicated, with which, as can be seen from the figure is, the power supply element 6 both on the cover 9 and is attached to the closure element 7. This connecting glass is also located between the cover 9 on the one hand and dtr Enclosure 1 and the closing element 7 on the other hand. Duroh the great length and the convenient location of this connecting glass an excellent vacuum-tight seal is obtained. In the corner seam located within the discharge space between the Stromzuftihrungselement 6 and the Absohlußelement 7 is almost no glass from the aggressive atmosphere could be attacked in the gas discharge space. There is a glass rim in the eek seam on the outside, but there ~ there is no danger of attack due to the aggressive atmosphere. The actual electrode consists of one in the power supply element 6 fastened element 22 made of molybdenum, for example. This element is known, for example Fastened to the tube 6, which can be made of niobium, with titanium. The end of the element 22 is pin-shaped and connected to a tungsten pin 23. With 24 a tungsten filament is indicated, which is around the pin-shaped Part and the pen is located. This tungsten filament can, if desired, be made with slightly electron-emitting material to be covered »

The modification of the termination shown in Fig. 3 shows the same elements as Fig. 2 and these are with the same Reference numbers indicated. The cover 9 in this embodiment a larger diameter than the envelope 1. This allows in the Eoknaht between the cover 9 and the Sheath 1 form a glass rim 28, which is an additional guarantee for a good gas-tight seal.

In the manufacture of a gas discharge lamp according to the invention. The first step is the envelope t with the Absehlußelementeeg

i i

7 and 8 provided. These closing elements are with an opening provided, in which the power supply element is attached must be »This is preferably done in the following way. You do one like in Pig. 4 compilation shown the tubular power supply element 6 with the electrode 22, 23, 24 attached to it. The tube 6 becomes the cover arranged from translucent densely sintered aluminum oxide 9. Rings 25 and 26, respectively, are placed above and below this cover arranged made of a vitreous joder glass-forming material exist, and for example have a composition, like this one in British patent specification No. 1.019.821 « has been written. A narrow strip or wire, for example made of molybdenum, which is attached to the power supply element 6, is indicated by 27. This serves to prevent that the power supply element 6 through the opening of the Cover 9 falls, and to ensure the correct position of the electrode in the envelope 1. After the entire assembly according to the figure has been made, this is on the closure element placed, wherein the power supply element 6 is pushed through the opening in this closing element. Thereon the rings 25 and 26 are melted by heating. The molten glass adheres both the power supply element 6 to the cover 9 and to the closure element. Simultaneously a layer of glass forms between the closure element and 'the lid, as already shown in Fig. 2.

5 shows a device with which the terminations of a gas discharge lamp according to the invention are produced can. This device consists of a bell 30 with With the help of seals 31 is connected to a frame. In the bell 30 there is an inner piston 32, which is attached to the upper Side is provided with an opening. In the piston 32 is a Metal block 36 coolable by water is arranged. The water can be supplied at 37 and discharged at 38 to the block

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Around 36 there is a quartz collar 39 in which four Wolf ram pens 40 are supported. These pins 40 in turn support one made of graphite on the upper side Cylinder 41. Level with graphite cylinder 41 is located A high-frequency heating coil 42 around the bell 30.

In the production of the gas-tight seal made of translucent Dense-sintered aluminum oxide existing envelope 43 moves mar. as follows. It gets from the wrapping assumed, in which the closure elements 44 and 45 are firmly sintered and on which the composition "according to Fig. is arranged at one end. The whole thing is placed in the metal ** block 36. Thereafter, the piston 32 is attached. then a pin 35 »an intermediate piece 33 and a spring 34 are arranged. Thereupon the bell 30 is arranged, whereby at the same time the pin 35 presses the Pig · 4 compilation. After all these parts are arranged, the ICUhI water becomes fed at 37 and the whole space inside the bell 30 and the envelope 43 with inert gas, for example argon, filled. Then, with the aid of the high-frequency helix 42 the graphite cylinder 41 is heated until the rings 4Θ from glass-forming Melt the material and the cover 49 and the power supply element 50 with the casing 43 and the closure element Λ4 can be connected in a gastight manner. After cooling down you can the bell 30 and the inner piston 32 are removed. Thereon you can remove the cover 43 with the finished closure

The same procedure can be used to create the termination on the other side. But before this conclusion is produced, the required amount of mercury can be added to the envelope. This does not need to be in one inert atmosphere. However, entering the alkali metal must be done in an inert atmosphere. In addition

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you can use the same device. One proceeds as follows follows. The casing sealed on one side is placed in block 36. Then the piston 32 is attached, after which An inert gas, for example argon, is supplied via the supply 46. The discharge 47 is closed. The gas fills the entire space within the piston 32 and it is ensured that the envelope 43 is filled with this gas will. The inert gas flows out of the piston 32 at the top. The required Amount of alkali metal, for example sodium, is placed in the envelope Wrapping arranged. Inert gas is still flowing » Then the pressing device 33, 34, 35 and the bell are attached. The feed 46 is closed and via 47 is the entire space inside the bell 30 is evacuated. The noble GPS, for example xenon, required in the finished lamp is then fed in via 46. Thereafter, by heating the second termination in the same way as the first .Abschluss made.

In the execution ^ form according to Fig ;. 6, for the most part the according to Pig * 1 is in the upper tubular power supply element 60 a pin 61 is arranged which is fastened at 62 in the outer bulb. This pin 61 fits something Clearance in the tubular element 60. During operation of the lamp, in which the actual discharge tube 63 becomes very warm can, this can expand unhindered at the top. The pin 61 and the tube 60 slide against each other. The power to the element 60 is supplied via the flexible 'wire 64, which on the one hand with this element 60 and on the other hand with the pole wire melted in the pinch 65 66 is connected.

PATEFTALI PROVERBS:

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Claims (6)

PATENT CLAIM 1,) Electric gas discharge lamp with an envelope of the Entlp.dungsraumes made of translucent, densely sintered aluminum oxide and at least one power supply element fastened gas-tight in the envelope, which envelope has a cylindrical part at the location of the power supply element, characterized in that there is a translucent seal in the cylindrical part -sintered aluminum oxide "existing closing element is located, which is sintered gas-tight to the envelope and has an opening in which the power supply element with the help of a connecting glass with a melting point higher than 800 ⁰ C and lower than that of the translucent, densely sintered aluminum oxide and the metal of the Power supply element is attached in a gas-tight manner, which lamp is also made of translucent, densely sintered aluminum oxide, which is supported against the end of the cylinder-shaped part of the envelope and against the terminating element located therein The existing cover is provided with an opening for the power supply element, which cover is connected in a gastight manner by a connecting glass with a melting point higher than 800 ⁰ C and lower than that of the translucent, densely sintered aluminum oxide and the metal of the power supply element with the casing, the terminating element and the power supply element is, 2. Electric gas discharge lamp according to claim 1, characterized in that the cover consists of the cylindrical part protrudes and that there is a connecting glass edge in the corner seam formed between these two parts. 3 ο electric gas discharge lamp according to claim 1 or 2, characterized in that the discharge space has at least one 00 98 22/0726 -H- BAD ORlGiNAl, Contains alkali metal, mercury and at least one noble gas. 4. Electric gas discharge lamp according to claim?, Characterized in that the alkali metal sodium un * " ^{1 is} the noble gas xenon. 5. Electric gas discharge lamp according to claim 1, 2, 3 or 4, characterized in that the power supply element consists largely of niobium. ™ 6. A method for producing an electric gas discharge lamp with zv / egg gas-tight Abschlus sen according to claim 1, 2, 3, 4 or 5, characterized in that first in a separate processing, both closure elements provided with an opening are sintered to the envelope, then in an inert atmosphere at a closure with the help of the connecting glass a power supply element and a cover are attached gas-tight, after which mercury and the alkali metal is brought into the discharge space through the opening in the other closure element and then the second power supply element and the second cover to the same ^T. \ ^r else be attached in an inert atmosphere in a gastight manner, whereby it is ensured that at the desired inert gas, for example xenon, in Entladungsr is?. 7. The method according to claim 6, characterized in that " the introduction of the sodium, the attachment of the second power supply element and the second lid takes place in a bell in which there is an inert atmosphere of the desired Noble gas is located. 8. The method according to claim 6 or 7, characterized in that that before attaching the power supply element this - 15 «00 9822/0726 Element, the lid and a certain amount of the jar or glass-forming material combined into a manageable whole the aiif the closing element is set, where the Power supply element through the opening of the closure element is plagued. ?. Electric gas discharge lamp according to Claim 1, 2, 3 »4 or 5, produced according to a method according to Claim 6 or 8, characterized in that. ^Q the lamp? does not have a pump nozzle. 10, electric gas discharge lamp according to claim 1, 2, 3 » or 5f in the case of the envelope of the discharge space in one evacuated or filled with inert gas outer bulb is arranged and at least one Stromzufi5hrun / ?; selement from a There is a small ear that is turned away from the ventilation area Side is open, characterized in that it is in the tubular Power supply element is a pin-shaped element which is arranged therein with little clearance and is firmly connected to the connecting piston Support element is located. 11. Electric gas discharge lamp according to claim 10 _f, characterized in that a flexible wire is electrically conductively connected on the one hand to a pole fastened in the outer bulb, for example in a pinch seal, and on the other hand to the tubular Stromauf ührungs element. 009822/072 5 BATH Blank page