JPH10154484A - Manufacture of discharge lamp and discharge lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lamp having a long life and a superior characteristic by sealing alloy pellets made of at least one kind of alkaline metal within alkaline metals and mercury and pellets made of mercury halide in an arc tube. SOLUTION: An alloy of an alkaline metals having a mercury/cesium atomic ratio of 6:1 and mercury is mixed to manufacture pellets. Pellets of cesium iodide and pellets of lanthanum iodide are manufactured respectively as a metal halide for sealing. An arc tube 1 made of translucent polycrystalline YAG and an external lead wire 7 made of thoriated tungsten, a niobium wire 6, and a platinum alloy are butted and welded integrally. Bases are fitted to seal sections 3 at both ends of the arc tube 1, both ends of the arc tube 1 are excited to light it, a heating reaction is started in the arc tube 1, and a halide of mercury and an alkaline metal is generated in the tube for manufacturing a lamp. The lamp can be operated at a mercury pressure of about 35atm with a life time of 1000hrs.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge lamp such as a mercury lamp and a metal halide lamp.

[0002]

2. Description of the Related Art Many discharge lamps contain mercury. Particularly, in an ultra-small metal halide lamp having a small internal volume of the arc tube, the amount of mercury enclosed is as small as about 1 mg. The mercury laser for mercury filling is a general-purpose
Since it has an accuracy of only about 0.5 mg, it cannot be used for filling 1 mg of mercury. Although a high-accuracy mercury laser capable of measuring and supplying such a small amount of mercury has been developed, it is expensive and maintenance is not easy.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to supply a small amount of mercury-containing material to a discharge lamp having a small arc tube having a small internal volume with high accuracy and reproducibility by a simple encapsulation method. In addition, another object of the present invention is to provide a small-sized discharge lamp having excellent lamp characteristics in which an enclosure is sealed by this method.

[0004]

According to the present invention, there is provided a pellet of an alloy comprising mercury and at least one alkali metal among lithium, sodium, potassium, rubidium and cesium, and a halogen. The above object is attained by providing a method for manufacturing a discharge lamp, wherein a pellet of mercury halide is sealed in an arc tube.

According to the second aspect of the invention, the number of halogen atoms constituting the alkali metal halide present in the arc tube is A, the number of halogen atoms constituting the halide other than alkali metal and mercury is B,
When the number of all halogen atoms in the arc tube is C and the stoichiometric deviation of the number of halogen atoms is R, then R =
[{C / (A + B)}-1] is 0.001 to 0.02
A discharge lamp manufactured by the manufacturing method according to claim 1, wherein

According to the third aspect of the present invention, when the total amount of alkali metal present in the arc tube made of translucent ceramics forms a halide, the theoretical number of halogen atoms is set to A, other than alkali metal and mercury. Assuming that the number of halogen atoms constituting the halide is B, the number of all halogen atoms in the arc tube is C, and the stoichiometric deviation of the number of halogen atoms is R, then R = [｛C / (A +
B) {-1} is in the range of -0.001 to -0.1, and a discharge lamp manufactured by the manufacturing method according to claim 1 is provided.

According to a fourth aspect of the present invention, in a discharge lamp having an arc tube having an inner volume of 0.2 cc or less, the amount of enclosed mercury is 10 mg / cc to 200 mg / cc. A discharge lamp according to the preceding claims.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The method of manufacturing a discharge lamp according to the present invention varies depending on the material of the arc tube to be used, but when a translucent ceramic is used for the arc tube, it is generally carried out by the following three steps. Step 1: An alkali metal-mercury alloy pellet prepared in a predetermined amount and a predetermined amount of mercury halide pellet are prepared. Step 2: The two kinds of pellets are loaded into a translucent ceramic arc tube, a predetermined buffer gas is sealed in the arc tube, and the arc tube is sealed at the end. Step 3: After sealing, the luminous tube is turned on to cause a reaction between the enclosures in the luminous tube to generate a predetermined amount of mercury and an alkali metal halide in the luminous tube as designed by the lamp.

In the case where silica glass is used for the arc tube, if the above-described steps are taken, the alkali metal and the alloy of mercury react with the glass, causing cloudiness.
Take the following method.

The steps up to preparing a pellet of an alkali metal-mercury alloy prepared in predetermined amounts and a predetermined amount of mercury halide pellets are the same as in the case of the above-mentioned ceramic arc tube. These pellets are previously sealed in an arc tube, both ends of the arc tube are sealed, and the mixture is heated in a furnace to cause a reaction between the enclosures to generate mercury and a halide of an alkali metal. However, in this case, the glass at the portion in contact with the alloy of alkali metal and mercury may be attacked, leaving a cloudy point.

[0011] Alternatively, a portion for storing an enclosure called a reservoir made of silica glass is provided in an exhaust pipe made of silica glass connected to the arc tube, and the enclosure in the reservoir is removed from the outside of the reservoir. A method of heating with a burner to cause a reaction between the enclosures to generate mercury and an alkali metal halide, leading the halide into the arc tube, and then disconnecting the reservoir.

Since the alloy of alkali metal and mercury shown in the above process has a higher melting point than mercury, it is solid at ordinary temperature, easy to handle, and is preferable as an enclosure for a discharge lamp. For example, an alloy of cesium and mercury is an alloy having a weight ratio of cesium of about 10% and a melting point of about 158 ° C., and can be formed into a solid pellet at room temperature and having a diameter of about 0.2 mm to 1 mm.

When the pellets are sealed in the arc tube by the method of the present invention, the weight of the pellets varies, so that the pellets of the alloy of alkali metal and mercury and the pellets of mercury halide are completely stoichiometric. Is almost impossible to enclose. For this reason, it is better to add a little more mercury halide. By doing so, extra halogen atoms present in the stoichiometric composition prevent blackening of the inner surface of the arc tube, so that there is an effect of improving the luminous flux maintenance rate during the operation of the lamp.

When the number of halogen atoms of the enclosed alkali metal halide is A, the number of halogen atoms of halides other than alkali metal and mercury is B, and the number of all halogen atoms is C, the stoichiometry of halogen If the deviation R, that is, R = [{C / (A + B)}-1] is smaller than 0.001, the blackening prevention effect is lost. When R is larger than 0.02, the erosion of the electrode by halogen is accelerated, and the probability of the electrode breaking increases.

When a light-transmitting ceramic such as alumina, yttria, yttrium aluminum garnet, or zirconia is used as the arc tube, a reaction between the arc tube and the alkali metal does not easily occur, so that a small amount of the alkali metal remains in the arc tube. The lamp can be manufactured under the conditions. That is, if the amount of the alkali metal-mercury alloy pellet is slightly increased, the starting property of the lamp is improved because the alkali metal remains in the lamp. A is the theoretical number of halogen atoms when the alkali metal in the arc tube produces a total amount of halide, B is the number of halogen atoms of halides other than the alkali metal and mercury, and all the halogen atoms are present in the arc tube. When the number is C, the stoichiometric deviation R of the halogen, that is, R = [｛C / (A +
B) When [-1] is larger than -0.01, the effect of improving the startability is practically lost. When R is smaller than -0.1, problems such as blackening appearing on the inner surface of the arc tube and starting discharge from the base of the electrode at the time of starting occur.

In a discharge lamp having an arc tube having an inner volume of 0.2 cc or less, high luminous efficiency cannot be obtained if the amount of mercury is lower than 10 mg / cc. The mercury amount is 200mg / cc
The higher the value, the higher the probability of rupture.

Next, a specific manufacturing method will be described.
FIG. 1 is a sectional view of a specific embodiment of the lamp of the present invention.
The sealing portion 3 is formed by winding the thoriated tungsten wires of the electrodes 2 a and 2 b with the alumina ceramic material 5 inside the light-transmitting YAG arc tube 1 and joining the inner wall surface 4 of the sealing portion. The thoriated tungsten wire is joined to an external lead wire 7 made of a platinum alloy via a niobium wire 6 in the end region of the sealing portion. In the present application, a thrusted tungsten wire, a niobium wire 6, and an external lead wire 7 made of a platinum alloy are butt-welded and integrated to be referred to as a power supply structure. The end of the sealing portion is sealed with frit glass 8. The niobium wire constituting the power supply structure may be a tantalum wire instead, and the platinum alloy serving as the external lead wire may be a cermet or nickel chromium alloy which is an oxidation-resistant material instead.

The above steps 1 to 3 will be described in detail for a 15 W ultra-high pressure mercury lamp. Step 1 includes preparing pellets. An alloy of an alkali metal and mercury having an atomic ratio of mercury to cesium of 6: 1 was prepared to produce a pellet. The weight per pellet was 0.1 mg. Similarly, pellets of mercury iodide, which is a mercuric halide weighing 0.16 mg per pellet, were prepared.
In addition, cesium iodide pellets weighing 0.25 mg per pellet and lanthanum iodide pellets weighing 0.25 mg per pellet were also prepared as metal halides for encapsulation.

Next, in step 2, a light-transmitting polycrystalline YAG
Butt welding of an outer diameter of 4.4 mm, an inner diameter of 3.0 mm, a light emitting part length of 6 mm, a total length of 28 mm, and a 0.3 mm diameter thoriated tungsten wire, a niobium wire and an external lead wire made of a platinum alloy. Then, an integrated power supply structure was prepared. Dy ₂ O ₃ -Al ₂ O ₃ -S
An iO ₂ glass frit press body was prepared. The melting temperature of the compression body is about 1500 ° C. The arc tube is shown in FIG.
However, as shown, the central portion is substantially spherical, and sealing portions having a smaller diameter than the central portion are provided at both ends.

The sealing of both ends of the arc tube is performed in a vacuum vessel, and high-frequency heating using, for example, a cylindrical tantalum sleeve is used to heat the sealing portion. Inserting the power supply structure from one end of the arc tube, inserting the glass frit press body without any gap so as to hold the power supply structure from one end of the arc tube, and installing the arc tube in a vacuum vessel. The luminous tube was held so that the sealing portion of the luminous tube was allowed to pass through a hollow cylindrical tantalum sleeve for heating.

The tantalum sleeve was heated by high frequency heating at a temperature of about 1600 ° C. for about 5 minutes to melt the glass frit and hermetically seal one end of the arc tube. The arc tube sealed at one end is moved into a glove box having a dew point of -80 ° C. or less, and nine 0.1 mg mercury-cesium alloy pellets prepared in step 1 are added to the arc tube, and mercury iodide is used. Cesium iodide 0.16 mg pellet
Six 25 mg pellets, 0.25 mg of lanthanum iodide
One pellet was loaded. Next, the power supply structure is inserted into the arc tube from the other end, and the glass frit press body is set without any gap so as to hold the power supply structure from the other end of the arc tube.

This is set in a vacuum container without exposing it to the outside air, and after evacuation, the portion of the glass frit where the pressed body is placed is subjected to high frequency heating to about 1450 ° C. to discharge gas. At this time, it is necessary to cool the light emitting unit so that the temperature of the light emitting unit at the center of the arc tube does not rise. Then, an argon gas is introduced into the vacuum vessel so as to have a pressure of 20 kPa, and a tantalum sleeve for heating is moved to about 16 kPa.
High-frequency heating is performed at a temperature of 00 ° C. for about 5 minutes to melt the glass frit and seal the other end of the arc tube.

In step 3, a cap is attached to a sealing portion at both ends of the arc tube, and both ends of the arc tube are energized to light up.
A heating reaction is caused inside the arc tube to generate mercury and a halide of an alkali metal in the arc tube, thereby completing the manufacture of the lamp. The lamp manufactured in this way has an inner volume of about 0.5 mm.
025 cc, a lamp voltage of 32 V and a lamp current of 0.
It operated at 5A at a mercury pressure of about 35 atmospheres and had a life of about 1000 hours.

As another embodiment, the 7W according to the present invention is used.
The ultra-high pressure mercury lamp is as follows. Pellets of an alloy having an atomic ratio of mercury to cesium of 6: 1 were produced. The 7W ultra-high pressure mercury lamp has an emission length of 1.0 mm and a diameter of 0.3 mm.
With an outer diameter of 3.2
mm and an arc tube made of translucent polycrystalline YAG having an inner volume of 0.012 cc. 0.45 mg of the above mercury / cesium alloy, 0.1 mg of mercury iodide pellets, and 0.1 mg of cesium iodide pellets were added to the 7 W ultrahigh pressure mercury lamp.
75 mg, lanthanum iodide 0.25 mg, and argon 20 kPa were sealed. This lamp has a lamp voltage of 22V,
A life of about 1000 hours was obtained at a lamp current of 0.35 A. And the deviation R of the stoichiometric composition was 0.022.

Further, as another embodiment, the 15th embodiment according to the present invention is described.
The W metal halide lamp is as follows. Pellets of an alloy having a 4: 1 atomic ratio of mercury to sodium were produced. 1
The 5W metal halide lamp has a light emitting length of 3.0 mm, is provided with a 0.3 mm-diameter 3-tungsten tungsten electrode, and is composed of an arc tube made of translucent polycrystalline alumina having an outer diameter of 4.4 mm and an inner volume of 0.025 cc. Is done. This 15W
In a metal halide lamp, 0.40 mg of the above-mentioned mercury-sodium alloy, 0.1 mg of mercury iodide pellets, and 0.3 mixed pellets of sodium iodide / dysprosium iodide
2 mg, thallium iodide 0.1 mg sealed, argon 13
kPa was enclosed. This lamp had a luminous efficiency of 55 lm / W and a color rendering index of 80 at a lamp voltage of 45 V and a lamp current of 0.35 A, and had a life of 6000 hours. And the deviation R of the stoichiometric composition was -0.017.

[0026]

As described above, both the pellets of an alloy composed of mercury and at least one of the alkali metals lithium, sodium, potassium, rubidium and cesium and the pellets of mercury halide are placed in the arc tube. The production method of a discharge lamp with a small arc tube with an inner volume of 0.2 cc or less can be manufactured with good reproducibility without using an expensive dozer by adopting a method of manufacturing a discharge lamp to be enclosed in a tube. can do. Further, a small-sized discharge lamp manufactured by the manufacturing method of the present invention can be a lamp excellent in characteristics such as long life.

[Brief description of the drawings]

FIG. 1 shows a sectional view of a specific embodiment of a discharge lamp manufactured by the manufacturing method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Arc tube 2a electrode 2b electrode 3 Sealing part 4 Inner wall surface of sealing part 5 Alumina ceramic material 6 Niobium wire 7 External lead wire of platinum alloy 8 Frit glass

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor: Shoji Miyanaga 1194, Sado Bessho-cho, Himeji-shi, Hyogo Ushio Electric Co., Ltd.

Claims (4)

[Claims] 1. At least one of lithium, sodium, potassium, rubidium and cesium alkali metals.
Pellets of alloys composed of various kinds of alkali metals and mercury,
A method for manufacturing a discharge lamp, wherein both mercury halide pellets are sealed in an arc tube. 2. The number of halogen atoms constituting the alkali metal halide present in the arc tube of the discharge lamp is A, the number of halogen atoms constituting the halide other than alkali metal and mercury is B, and all the halogen atoms in the arc tube are present. Assuming that the number of atoms is C and the stoichiometric deviation of the number of halogen atoms is R, R = [{C / (A + B)}-1]
The discharge lamp manufactured by the manufacturing method according to claim 1, wherein is in the range of 0.001 to 0.02. 3. An arc tube made of a translucent ceramic,
The theoretical number of halogen atoms when the alkali metal present in the arc tube forms a halide in total amount is A,
Assuming that the number of halogen atoms constituting a halide other than the alkali metal and mercury is B, the number of all halogen atoms in the arc tube is C, and the stoichiometric deviation of the number of halogen atoms is R, R = [ {C / (A + B)}-1] is-
The discharge lamp manufactured by the manufacturing method according to claim 1, wherein the discharge lamp has a range of 0.01 to -0.1. 4. The discharge lamp according to claim 2, wherein the amount of the enclosed mercury is 10 mg / cc to 200 mg / cc in a discharge lamp having an inner volume of the arc tube of 0.2 cc or less. Discharge lamp.