JP4358959B2 - Discharge lamp - Google Patents

Description

【００４２】
【表２】

【００４３】
封入濃度を上げ3.2×10^-3μmol／mm³を越える、浮遊ハロゲンとアークとが反発しゆらぎが発生した。これらの結果から封入するハロゲンの量はハロゲンの量が1.1×10^-4〜3.2×10^-3μmol／mm³の範囲が、アーク揺らぎの点でも寿命の点でも適しているといえる。
【００４４】
したがって以下の実験はハロゲン量が1．1×10^-4〜3．2×10^-3μmol／mm³の条件で行う。又、ハロゲンとしてはHgBr₂を使用する。
【００４５】
次に含まれる不純物をリチウム、ナトリウム、カリウムとの3種とし、その濃度を変化させた、異なる種々のタングステン電極を用い、寿命特性を比較した。封入金属としてはHgBr₂を使用し、放電容器は上記実験と同じ1.9PPMのアルカリ成分を含む石英硝子からなるものを使用した。
【００４６】
ハロゲン量を1.6×10^-4μmol／mm³としたときの実験結果を表３に、3.2×10^-3μmol／mm³としたときの実験結果を表４に示す。
【００４７】
いずれの実験においてもタングステン電極中のアルカリ金属がリチウム又は／及びナトリウムに特定され、その濃度が75PPM以下となるものが請求項１記載の発明の実施例となる。
【００４８】
【表３】

【００４９】
【表４】

【００５０】
ハロゲン量が1．6×10^-4μmol／mm³の場合も、3．2×10^-3μmol／mm³の場合もタングステン電極中の不純物であるアルカリ金属がリチウム又は／及びナトリウムの場合で、その濃度が75PPM以下の場合、すなわち本実施例の場合に良好な寿命が得られることがわかる。
【００５１】
［参考例］
ハロゲン量を1.6×10^-4μmol／mm³とした場合と、3.2×10^-3μmol／mm³とした場合について、石英硝子中のアルカリ金属の総量が種々異なる放電容器を用いて、寿命を比較した。
【００５２】
電極は実施例1と異なり、タングステン中のアルカリ金属がカリウムでその濃度が75PPMの従来型電極を使用している。
【００５３】
ハロゲン量を1．6×10^-4μmol／mm³としたときの実験結果を表５に、3．2×10^-3μmol／mm³としたときの実験結果を表６に示す。いずれの実験においても石英硝子中のアルカリ成分の総量が0.6PPM以下のものが請求項２記載の発明の実施例となる。
【００５４】
【表５】

【００５５】
【表６】

【００５６】
いずれの場合もアルカリ成分の総量が0．6PPM以下の本実施例の場合は、1000時間維持率も2000時間維持率も共に良好であることがわかる。
【００５７】
［実施例２（請求項２記載の発明の実施例）］
実施例1と同様にタングステン中のアルカリ金属がリチウム又は／及びナトリウムに特定され、その濃度が75PPM以下の電極を使用すると共に、参考例と同様に石英硝子中のアルカリ金属の総量が0.6PPMの放電容器を使用し、ハロゲン量を1.6×10^-4μmol／mm³とした場合と、3.2×10^-3μmol／mm³とした場合について、寿命を比較した。
【００５８】
ハロゲン量を1.6×10^-4μmol／mm³としたときの実験結果を表７に、3.2×10^-3μmol／mm³としたときの実験結果を表８に示す。いずれも請求項２記載の発明の実施例となる。
【００５９】
【表７】

【００６０】
【表８】

【００６１】
いずれの場合も、1000時間維持率も2000時間維持率も共に極めて良好であることがわかる。
【００６２】
［実施例３（請求項３記載の発明の実施例）］
ハロゲン量を1.6×10^-4μmol／mm³とした場合と、3.2×10^-3μmol／mm³とした場合について、1.9PPMのアルカリ金属を含む石英硝子からなる従来型の放電容器を用い、電極の金属ドープに用いるドープ材の濃度を変化させて寿命を比較した。
【００６３】
ドープ材としてはアルカリ金属以外の金属又はその酸化物からなる濃度が0.1 PPM以上100PPM以下のドープ材が適しているが、特に点灯中に電極から不純物として放出されにくい傾向を有するランタノイド類（La，Ce，Pr，Nd，Pm，Eu，Cd，Tb，Dy，Ho，Er，Tm，Yb，Lu）金属又はその酸化物を用いることが好ましい。尚、ドープ材濃度の下限を0.1PPMとしたのは、タングステンの成型可能なドープ下限濃度が0.1PPMだからである。
【００６４】
本実施例ではドープ材として酸化ディスプロシウムを用いた。ハロゲン量を1.6×10^-4μmol／mm³としたときの実験結果を表９に、3.2×10^-3μmol／mm³としたときの実験結果を表１０に示す。
【００６５】
いずれの実験においてもドープ材濃度が100PPM以下のものが請求項３記載の発明の実施例となる。
【００６６】
【表９】

【００６７】
【表１０】

【００６８】
いずれの場合も、タングステン中のドープ材濃度が100PPM以下の本実施例では、1000時間維持率も2000時間維持率も共に良好であることがわかる。
【００６９】
［実施例４（請求項４記載の発明の実施例）］
実施例３と同様にドープ材濃度が100PPM以下の電極を使用すると共に、参考例と同様に石英硝子中のアルカリ金属の総量が0.6PPMの放電容器を使用し、ハロゲン量を1.6×10^-4μmol／mm³とした場合と、3.2×10^-3μmol／mm³とした場合について、寿命を比較した。
【００７０】
ハロゲン量を1.6×10^-4μmol／mm³としたときの実験結果を表１１に、3.2×10^-3μmol／mm³としたときの実験結果を表１２に示す。いずれも請求項４記載の発明の実施例となる。
【００７１】
【表１１】

【００７２】
【表１２】

【００７３】
いずれの場合も、1000時間維持率も2000時間維持率も共に極めて良好であることがわかる。
【００７４】
【発明の効果】
以上述べたように本発明により、製造が容易で、ランプ内に炭素や水素を持ち込まず、また封入ハロゲン量の多い中で長時間にわたって安定した色調と光学系内での光束を維持可能な放電灯を提供することができる。
【図面の簡単な説明】
【図１】一般的な放電灯の基本構成を示した図。
【符号の説明】
(1) 放電容器
(2) 電極
(3) 容器内空間
(4) ピンチシール部
(5) 金属箔
(6) 外部リード棒[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a discharge lamp capable of maintaining a stable color tone and a luminous flux in an optical system over a long period of time.
[0002]
[Prior art]
As disclosed in Japanese Patent Application Laid-Open No. 6-52830, there is a lamp in which a very small amount of halogen is encapsulated in order to obtain a long life, but the halogen concentration is 1 × 10 ⁻⁵ to 1 × 10 ⁻⁴ μmol / It is extremely low at ³ mm.
[0003]
When encapsulating it as metal halide lamp, for example, the internal volume 0.08Cc, the pellets of 0.0015 × 10 ^-2 ~0.0015mg in case of the metal halide and mercuric bromide.
[0004]
However, the manufacture of metal halide pellets of the size is impossible, about 0.005mg is the limit. Therefore, it is impossible to encapsulate the lamp in the lamp manufacturing process without variation.
[0005]
The only means for encapsulating the halogen content was to encapsulate using the vapor pressure of a hydrocarbon halide such as CH ₂ Br ₂ or a hydrogen halogen such as HBr.
[0006]
However, this enclosing method requires attention to temperature control in the lamp manufacturing process, and if the temperature control is not sufficient, the encapsulating concentration varies.
[0007]
In addition, each of the enclosed halides brings in carbon and hydrogen, both of which adversely affect the lamp. For example, carbon carbonizes the tungsten of the electrode, reducing its strength, and hydrogen activates the tungsten transport of the electrode to promote blackening of the lamp.
[0008]
In the range which can be sealed as the spec clogging metal halides, consider the case where the halogen amount to produce a lamp 1 × 10 ^-4 μmol / mm ³ large metal halide sealed than.
[0009]
For example sealed metal halide amount as that described in JP-A-11-86785 is in 0.04~0.3mg / cc, which when sealed metal halide compound is DyBr _3, the halogen concentration of 3 × 10 ^-4 It is in the range of ˜2.2 × 10 ⁻³ μmol / mm ³ .
[0010]
In the case of the present invention, the lifetime of the lamp is longer than that of a lamp having a halogen concentration exceeding this range, but the luminous flux maintenance factor in the optical system is limited to 50% at 1000 hours.
[0011]
This is mainly because the alkali metal in the electrode or quartz glass reacts with the excess halogen to float the alkali halide in the lamp and the potassium halide remains in the discharge vessel.
[0012]
This is because potassium halide remaining in the discharge vessel during lamp operation creates devitrified nuclei of quartz glass, spreading the devitrification during long-time lamp operation, and increasing the luminous flux maintenance rate in the optical system. Lowering and changing the color of the lamp.
[0013]
Furthermore the lower metal halide of such excitation energy level of potassium halide remains in the lamp, including light emitting where the alkali halide is separated from the center of the arc, to reduce the energy of the arc near the center, in the optical system This reduces the luminous flux at. Further , the residual potassium halide increases the residual amount with the lighting time, and causes the luminous flux to decrease with the lighting time.
[0014]
[Problems to be solved by the invention]
Accordingly, an object of the present invention is to provide a discharge lamp that does not bring carbon or hydrogen into the lamp and can maintain a stable color tone and light flux in the optical system over a long period of time with a large amount of encapsulated halogen.
[0015]
[Means for Solving the Problems]
The discharge lamp according to claim 1 of the present invention includes an electrode made of tungsten whose alkali metal contained as an impurity is specified as lithium and / or sodium, and the concentration of the alkali metal is 75 PPM or less, and the enclosed halogen amount is 1.1 × 10 ^{−4 to} 3.2 × 10 ⁻³ μmol / mm ³ .
[0016]
If a metal halide is used as the encapsulated halogen, the size becomes 0.005 mg or more, which is the range in which pellets can be manufactured, and manufacturing is facilitated. The same applies to the invention according to the following claims.
[0017]
In addition, by specifying the alkali metal that is an impurity in the tungsten electrode as lithium, sodium, or lithium and sodium, and by setting the concentration to 75 PPM or less, alkali halide in the lamp due to excessive encapsulated halogen is generated. Residue can be prevented.
[0018]
The tungsten electrode is usually doped with potassium for the convenience of processing, and the residual amount in the finished electrode product is 75 PPM. This potassium floats in the discharge vessel as potassium halide by reaction with excess halogen during lamp operation.
[0019]
Potassium has a large ionic radius, whereas lithium and sodium have small ionic radii of 0.6 angstrom and 0.98 angstrom, respectively. Even when floating in the discharge vessel due to excess halogen, when it is ionized during lighting, the discharge vessel The quartz glass does not escape from the stitch structure and remains in the discharge vessel.
[0020]
Therefore, the quartz glass, which is a discharge vessel during lighting, does not devitrify, and the luminous flux can be maintained well without deteriorating the luminous flux due to the increase in residual alkali halide.
[0024]
In the discharge lamp according to claim 2, the alkali metal contained as impurities is specified as lithium or / and sodium, the concentration of the alkali metal is 75 PPM or less, and the total amount of alkali metals in the quartz glass is 0.6. A discharge vessel having a PPM or less is provided, and the amount of enclosed halogen is 1.1 × 10 ^{−4 to} 3.2 × 10 ⁻³ μmol / mm ³ .
[0025]
A conductive electrode material, by specifying the discharge vessel material to the above range, it is possible to further effectively prevent the floating and residual alkali halide into the lamp due to excessive inclusion halogen.
[0026]
In the discharge lamp according to claim 3, the alkali metal contained as an impurity is specified as lithium or / and sodium, and the concentration of the alkali metal is 75 PPM or less, and the concentration of the metal other than the alkali metal or its oxide is used. A tungsten electrode doped with a doping material of 0.1 PPM or more and 100 PPM or less is provided, and the amount of encapsulated halogen is 1.1 × 10 ^{−4 to} 3.2 × 10 ⁻³ μmol / mm ³ .
[0027]
By setting the halogen concentration range in the lamp to 1.1 × 10 ^{−4 to} 3.2 × 10 ⁻³ , even if metal halogen is used as the encapsulated halogen, the size becomes 0.005 mg or more, which is the range in which pellets can be manufactured. Manufacturing becomes easy.
[0028]
Metals and oxides other than alkali metals are used for the electrode dope used to prevent the alkali halide from floating in the lamp due to excessive encapsulated halogen, and the concentration is 0.1 PPM or more and 100 PPM or less.
[0029]
In the case of metal doping other than alkali metal, the metal floats in the discharge vessel due to excess halogen, and even if it remains, it does not form devitrification nuclei of quartz glass like alkali metal, and Since it is not a low melting point metal, the probability of floating from the electrode into the discharge vessel due to excess halogen is very low.
[0030]
In the discharge lamp according to claim 4, the alkali metal contained as an impurity is specified as lithium and / or sodium, and the concentration of the alkali metal is 75 PPM or less, and the concentration of the metal other than the alkali metal or its oxide is used. A tungsten electrode doped with a doping material of 0.1 PPM or more and 100 PPM or less and a discharge vessel in which the total amount of alkali metals in quartz glass is 0.6 PPM or less, and the enclosed halogen amount is 1.1 × 10 ^{−4 to} 3.2 × 10 6 ^-3 μmol / mm.
[0031]
By identifying the conductive electrode material and the discharge container material to those of the above-mentioned range, as compared to the invention of claim 3, further to effectively prevent stray residual alkali halide into the lamp due to excessive inclusion halogen be able to.
[0032]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described below with reference to preferred embodiments.
[0033]
FIG. 1 is a diagram illustrating a basic configuration of a general discharge lamp. (1) is a discharge vessel made of quartz glass, and has an internal space (3) in which halogen is sealed at the center. (2) is an electrode protruding from the seal part (4) on both sides into the internal space (3) of the discharge vessel (1), and is connected to the external lead rod (6) via the metal foil (5). The periphery of the metal foil (5) is sealed with a seal portion (4).
[0034]
In the present invention, the electrode material, the discharge vessel material, and the amount of encapsulated halogen are specified, and the shape and size of each member are not particularly limited.
[0035]
In conventional lamps, a tungsten electrode with 75PPM potassium is usually used, and a slight devitrification is confirmed on the inner wall of the quartz glass, which is the container in about 100 hours, and the luminous flux maintenance factor in the optical system is reached in 1000 hours. Was down to 50%.
[0036]
On the other hand, in the present invention, by specifying the electrode material, the discharge vessel material, and the amount of encapsulated halogen, devitrification is not confirmed until the end of the life, and 90% in 1000 hours and up to about 80% in 2000 hours can be obtained. Can do.
[0037]
Hereinafter, the present invention will be described together with embodiments corresponding to the respective claims.
[0038]
[Embodiment 1 (Invention of Claim 1)]
First, a test was conducted to examine the amount of halogen contained. Using HgBr ₂ and DyI ₂ as halogen, by changing the amount of halogen was investigated preferred ranges. The quality was judged by “arc fluctuation” and life (1000-hour maintenance rate and 2000-hour maintenance rate).
[0039]
The electrode used was a conventional tungsten electrode of 75PPM potassium, and a conventional discharge vessel made of quartz glass containing an alkaline component of 1.9PPM.
[0040]
The results when HgBr ₂ is used are shown in Table 1, and the results when DyI ₃ is used are shown in Table 2.
[0041]
[Table 1]

[0042]
[Table 2]

[0043]
Fluctuation occurred due to repulsion of floating halogen and arc that increased the concentration of inclusion and exceeded 3.2 × 10 ⁻³ μmol / mm ³ . From these results, it can be said that the amount of halogen to be encapsulated is in the range of 1.1 × 10 ^{−4 to} 3.2 × 10 ⁻³ μmol / mm ³ in terms of arc fluctuation and life.
[0044]
Therefore, the following experiment is performed under the condition that the halogen content is 1.1 × 10 ^{−4 to} 3.2 × 10 ⁻³ μmol / mm ³ . As the halogen, HgBr ₂ is used.
[0045]
Next, the life characteristics were compared using various different tungsten electrodes with different concentrations of lithium, sodium, and potassium as the impurities contained therein. HgBr ₂ was used as the encapsulating metal, and the discharge vessel was made of quartz glass containing the same 1.9 PPM alkali component as in the above experiment.
[0046]
The experimental results when the halogen content is 1.6 × 10 ⁻⁴ μmol / mm ³ are shown in Table 3, and the experimental results when the halogen content is 3.2 × 10 ⁻³ μmol / mm ³ are shown in Table 4.
[0047]
In any of the experiments, the alkali metal in the tungsten electrode is specified as lithium or / and sodium, and the concentration is 75 PPM or less.
[0048]
[Table 3]

[0049]
[Table 4]

[0050]
When the halogen content is 1.6 × 10 ⁻⁴ μmol / mm ³ or 3.2 × 10 ⁻³ μmol / mm ³ , the alkali metal that is an impurity in the tungsten electrode is lithium or / and sodium. It can be seen that a good lifetime can be obtained when the concentration is 75 PPM or less, that is, in the case of this example.
[0051]
[ Reference example ]
When the halogen content is 1.6 × 10 ⁻⁴ μmol / mm ³ and 3.2 × 10 ⁻³ μmol / mm ³ , the lifespan can be increased by using discharge vessels with different total amounts of alkali metals in quartz glass. Compared.
[0052]
Unlike Example 1, the electrode is a conventional electrode in which the alkali metal in tungsten is potassium and its concentration is 75 PPM.
[0053]
Table 5 shows the experimental results when the halogen content is 1.6 × 10 ⁻⁴ μmol / mm ^3, and Table 6 shows the experimental results when the halogen content is 3.2 × 10 ⁻³ μmol / mm ³ . In any experiment, the total amount of alkali components in the quartz glass is 0.6 PPM or less.
[0054]
[Table 5]

[0055]
[Table 6]

[0056]
In any case, in the case of the present example in which the total amount of alkali components is 0.6 PPM or less, both the 1000-hour maintenance rate and the 2000-hour maintenance rate are good.
[0057]
[Embodiment 2 (Embodiment of Invention of Claim 2 )]
As in Example 1, an alkali metal in tungsten is specified as lithium or / and sodium, and an electrode having a concentration of 75 PPM or less is used, and the total amount of alkali metals in quartz glass is 0.6 PPM as in Reference Example . The lifespan was compared between the case where a discharge vessel was used and the halogen content was 1.6 × 10 ⁻⁴ μmol / mm ³ and 3.2 × 10 ⁻³ μmol / mm ³ .
[0058]
Table 7 shows the experimental results when the halogen content is 1.6 × 10 ⁻⁴ μmol / mm ^3, and Table 8 shows the experimental results when the halogen content is 3.2 × 10 ⁻³ μmol / mm ³ . Either of these is an embodiment of the invention described in claim 2 .
[0059]
[Table 7]

[0060]
[Table 8]

[0061]
In either case, it can be seen that both the 1000-hour maintenance rate and the 2000-hour maintenance rate are extremely good.
[0062]
[Embodiment 3 (Embodiment of Invention of Claim 3 )]
For the case where the halogen content is 1.6 × 10 ⁻⁴ μmol / mm ³ and 3.2 × 10 ⁻³ μmol / mm ³ , a conventional discharge vessel made of quartz glass containing 1.9 PPM alkali metal is used. The lifetime was compared by changing the concentration of the doping material used for the metal doping of the electrode.
[0063]
As the doping material, a doping material composed of a metal other than an alkali metal or an oxide thereof having a concentration of 0.1 PPM or more and 100 PPM or less is suitable, but in particular, lanthanoids (La, (Ce, Pr, Nd, Pm, Eu, Cd, Tb, Dy, Ho, Er, Tm, Yb, Lu) It is preferable to use a metal or an oxide thereof. The lower limit of the doping material concentration is set to 0.1 PPM because the lower limit doping concentration of tungsten that can be molded is 0.1 PPM.
[0064]
In this example, dysprosium oxide was used as a doping material. The experimental results when the halogen content is 1.6 × 10 ⁻⁴ μmol / mm ³ are shown in Table 9, and the experimental results when the halogen content is 3.2 × 10 ⁻³ μmol / mm ³ are shown in Table 10.
[0065]
Others dopant concentration is less than 100PPM is an embodiment of the invention described in claim 3 in any of the experiments.
[0066]
[Table 9]

[0067]
[Table 10]

[0068]
In either case, it can be seen that both the 1000-hour retention rate and the 2000-hour retention rate are good in this example in which the concentration of the dopant in tungsten is 100 PPM or less.
[0069]
[Embodiment 4 (Embodiment of Invention of Claim 4 )]
As in Example 3 , an electrode having a doping material concentration of 100 PPM or less was used, and similarly to the reference example , a discharge vessel in which the total amount of alkali metals in quartz glass was 0.6 PPM was used, and the halogen content was 1.6 × 10 ^−4. The lifetime was compared between the case of μmol / mm ³ and the case of 3.2 × 10 ⁻³ μmol / mm ³ .
[0070]
Table 11 shows the experimental results when the halogen content is 1.6 × 10 ⁻⁴ μmol / mm ^3, and Table 12 shows the experimental results when the halogen content is 3.2 × 10 ⁻³ μmol / mm ³ . Either of these is an embodiment of the invention described in claim 4 .
[0071]
[Table 11]

[0072]
[Table 12]

[0073]
In either case, it can be seen that both the 1000-hour maintenance rate and the 2000-hour maintenance rate are extremely good.
[0074]
【The invention's effect】
As described above, according to the present invention, it is easy to manufacture, does not bring carbon or hydrogen into the lamp, and is capable of maintaining a stable color tone and light flux in the optical system for a long time with a large amount of encapsulated halogen. Electric light can be provided.
[Brief description of the drawings]
FIG. 1 is a diagram showing a basic configuration of a general discharge lamp.
[Explanation of symbols]
(1) Discharge vessel
(2) Electrode
(3) Container space
(4) Pinch seal part
(5) Metal foil
(6) External lead bar

Claims (4)

An alkali metal contained as an impurity is specified as lithium and / or sodium, and an electrode made of tungsten having a concentration of the alkali metal of 75 PPM or less is provided. The amount of encapsulated halogen is 1.1 × 10 ^{−4 to} 3.2 × 10 ⁻³ μmol. A discharge lamp characterized by being / mm ³ . As specified in the alkali metal is lithium and / or sodium contained as an impurity, comprising an electrode density of the alkali metal consists of the following tungsten 75 ppm, the total amount of alkali metal in the quartz glass is the following discharge vessel 0.6 ppm, A discharge lamp characterized in that the amount of enclosed halogen is 1.1 × 10 ^{−4 to} 3.2 × 10 ⁻³ μmol / mm ³ . The alkali metal contained as an impurity is specified as lithium or / and sodium, and the concentration of the alkali metal is 75 PPM or less by a doping material made of a metal other than the alkali metal or its oxide and having a concentration of 0.1 PPM to 100 PPM. A discharge lamp comprising a doped tungsten electrode, wherein the amount of enclosed halogen is 1.1 × 10 ^{−4 to} 3.2 × 10 ⁻³ μmol / mm ³ . The alkali metal contained as an impurity is specified as lithium or / and sodium, and the concentration of the alkali metal is 75 PPM or less by a doping material made of a metal other than the alkali metal or its oxide and having a concentration of 0.1 PPM to 100 PPM. A doped tungsten electrode and a discharge vessel in which the total amount of alkali metals in quartz glass is 0.6 PPM or less are provided, and the amount of enclosed halogen is 1.1 × 10 ^{−4 to} 3.2 × 10 ⁻³ μmol / mm ³ A discharge lamp characterized by

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