JP4208222B2 - Short arc metal halide lamp for headlamp, metal halide lamp lighting device and headlamp - Google Patents

Description

表２から明らかなように、本実施例においては、ランプ電圧が５０Ｖ以上で、発光効率は比較例より若干低いが、演色性が向上する傾向が見られた。
【０１１３】
以上から、本実施例は、定常時の特性が比較例とほぼ同等であると評価できる。
【０１１４】
次に、表２における本実施例のランプ３とランプ１（比較例）とについて、入力電力１５Ｗ、２０Ｗ、２５Ｗおよび３０Ｗで点灯したときの演色性および色温度を測定した結果を表３に示す。
【０１１５】
【表３】

表３に示すように、ランプ１の比較例では３５Ｗ（表２に関連する説明を参照）から１５Ｗまで入力を変化させた場合、色温度が１５２０Ｋ変化し、演色性は２３変化した。これでは変化が大きすぎて、実際上調光できない。
【０１１６】
これに対して、本実施例においては、色温度の変化は３２０Ｋ、演色性の変化はわずかに８であり、十分調光が可能である。
【０１１７】
次に、再始動について評価した結果を表４に示す。
【０１１８】
なお、ランプ１０として、キセノンＸｅを１００Ｔｏｒｒ封入した以外はランプ３と同一仕様のものを製作して、これについても再始動電圧を測定した結果を示している。
【０１１９】
【表４】

表４に示すように、本実施例において、再始動電圧は比較例の半分であった。なお、参考として特に希ガスの封入圧を低くして、光束立ち上がりを重視しないランプ１０においては、さらに著しい改善が見られた。
【０１２０】
図３は、本発明の前照灯用短アーク形メタルハライドランプの第１の実施形態において、キセノンＸｅの封入圧に対する光束立ち上がり時間の関係を示すグラフである。図において、横軸はＸｅ封入圧（気圧）を、縦軸は光束立ち上がり時間（秒）を、それぞれ示す。
【０１２１】
図から明らかなように、封入圧が１気圧以上になると、光束立ち上がり時間が著しく短縮されるが、１気圧未満では著しく長い。
【０１２２】
図４は、同じく第１の実施形態において、第２のハロゲン化物としてヨウ化鉄ＦｅＩ２を用いた場合の封入量に対するランプ電圧の関係を示すグラフである。図において、横軸はＦｅＩ_２の封入量（ｍｇ／ｃｃ）を、縦軸はランプ電圧（Ｖ）を、それぞれ示す。
【０１２３】
図によれば、ランプ電圧が３０Ｖを超えるのは気密容器の内容積１ｃｃ当たり１ｍｇ以上であることが分かる。
【０１２４】
なお、気密容器の内容積１ｃｃ当たり２００ｍｇ以上では未蒸発のＦｅＩ２が光を吸収するために発光効率が低下する。
【０１２５】
図５は、本発明の前照灯用短アーク形メタルハライドランプの第２の実施形態を示す正面図である。図において、図２と同一部分については同一符号を付して説明は省略する。
【０１２６】
本実施形態は、図２に示すのと同様な発光管ＩＢを移動体の前照灯に実際に装着しやすいように構成したものである。図において、ＯＢは外管、Ｂは口金、ＩＴは絶縁チューブである。
【０１２７】
外管ＯＢは、紫外線カット性能を備えており、内部に図２に示すのとほぼ同様な構造の発光管ＩＢを収納していて、両端が気密容器１の一対の封止部１ｂに固定されているが、内部は気密ではなく、外気に連通している。また、一方の封止部１ｂが口金Ｂに植立されている。外管ＯＢの先端側の端部から外部へ導出された外部リード線４は、外管ＯＢに平行に折り返されて口金Ｂ内に導入され、図示しない端子に接続されている。
【０１２８】
絶縁チューブＩＴは、外部リード線４を被覆する。
【０１２９】
図６は、本発明の前照灯の第１の実施形態を示す斜視図である。
【０１３０】
図において、３１は反射鏡、３２は前面カバーである。
【０１３１】
反射鏡３１は、プラスチックスの成形によって異形の回転放物面に形成され、頂部背面から図５に示すメタルハライド放電ランプ（図示しない。）を着脱するように構成されている。
【０１３２】
前面カバー３２は、透明性のプラスチックスの成形によりプリズムまたはレンズを一体に形成していて、反射鏡３１の前面開口に気密に装着される。
【実施例２】
本実施例は、図２に示す前照灯用短アーク形メタルハライドランプの構造およびサイズにおいて、以下の放電媒体を用いた。
放電媒体：第１のハロゲン化物はヨウ化スカンジウムＳｃＩ_３０．１４ｍｇ、ヨウ化ナトリウムＮａＩ０．７ｍｇ、第２のハロゲン化物は表５に示すハロゲン化物０．４ｍｇ、キセノンは５気圧
また、比較例として、さらに水銀を１ｍｇ封入したものを製作した。
【０１３３】
そうして、本実施例および比較例について、ランプ入力３５Ｗ一定で点灯して、ランプ電圧、発光効率、演色性（平均塩色評価数）Ｒａおよび色温度を測定した結果を表５に示す。
【０１３４】
【表５】

比較例のランプ電圧は、水銀の封入量で決まるが、本実施例では第２のハロゲン化物の蒸発量で決まる。したがって、発光管の保温を良好にしておくことにより、所要のランプ電圧を容易に得ることができる。表５から理解できるように、本実施例において、ランプ電圧は比較例より低めになるが、５０Ｖ以上であり、この種の小形の前照灯用短アーク形メタルハライドランプは、電子化点灯回路を用いて点灯するので、実用上問題はない。特性面では、発光効率は少し劣るが、可視域に少し添加金属（アルミニウムＡｌなど）の発光があるので、演色性は向上する傾向がある。
【０１３５】
図７は、本発明の実施例２における表５のランプ２および比較例であるランプ１の色度の変化を示す色度図である。
【０１３６】
この色度図は、日本工業規格ＪＩＳ Ｄ ５５００-1984において自動車用ランプ類の解説の中で説明されている白の色度範囲を示している。そして、図中曲線Ｃは、本実施例の色度の変化を示す。曲線Ｄは、比較例の色度の変化を示す。各曲線の測定点の近くに付与した数字は、点灯開始後の経過時間（秒）を示している。これらの測定は、各ランプを電源入力直後に２．６Ａのランプ電流を流し、徐々に電流を絞って３５Ｗの定格ランプ電力に定電力制御するように設定した電子化点灯回路を用いて点灯して行った。
【０１３７】
図から明らかなように、本実施例においては、点灯後０．５秒以内に発光が白色範囲に入るのに対して、比較例では１８秒後に白色範囲に入った。
【０１３８】
次に、表５におけるランプ２および１をランプ入力１５Ｗ、２０Ｗ、２５Ｗおよび３０Ｗで点灯したときの平均演色評価数Ｒａおよび色温度（Ｋ）を測定した結果を表６に示す。
【０１３９】
【表６】

ランプ１（比較例）は、水銀の蒸気圧が高いので、ランプ入力１５Ｗに低減しても水銀は全て蒸発している。このため、ランプ入力が少なくなるにしたがって水銀の発光が支配的になってきて色温度が上昇し、反対に演色性が低下していくので、比較例は実用的な意味で調光には向かないことが理解できるであろう。
【０１４０】
これに対して、ランプ２（本実施例）は、演色性および色温度とも変化が少なく、十分調光に適していることを理解できる。
【０１４１】
さらに、本実施例の瞬時再始動（ホットリスタート）の際の再始動電圧を測定した結果を表７に示す。測定は、ランプを３０分間点灯して消灯し、１０秒後に再始動させたときの再始動電圧を測定した。なお、消灯時間が長くなると、電極温度が低下して始動しにくくなる。一方、発光管内の水銀や金属ハロゲン化物の蒸気圧は消灯時間が長くなると、低下して始動しやすくなる。これらの相反する傾向の結果、再始動は消灯時間が１０秒程度が最も始動しにくい。
【０１４２】
【表７】

ランプ１（比較例）は、水銀蒸気圧がまだ高いため、始動電圧が高い。
【０１４３】
これに対して、ランプ２〜６（本実施例）は、定常点灯中においては第２の金属ハロゲン化物の金属蒸気圧が水銀のそれより明らかに低い。それでも消灯後１０秒は、金属ハロゲン化物の金属蒸気圧と水銀との蒸気圧差が最も少なくなっているときである。このことは、本実施例は、再始動特性が水銀を封入する従来例に比べてすこぶる良好であることを示している。
【０１４４】
次に、本実施例のランプを直流点灯した場合の電極付近の色特性を測定した結果を表８に示す。なお、これはランプをランプ入力３５Ｗで点灯したときにスクリーンに投影して、陽極付近と陰極付近との色温度（Ｋ）を測定して求めたものである。
【０１４５】
【表８】

ランプ１（比較例）は、陽極側と陰極側との色温度の差が大きい。このような色温度差を前照灯の設計でカバーするのは無理である。
【０１４６】
これに対して、ランプ２〜６（本実施例）は、色温度差が小さいので、十分実用に適している。
【実施例３】
本実施例は、図５に示す前照灯用短アーク形メタルハライドランプにおいて、外管２１の両端をそれぞれ発光管１の封止部１ｂ、１ｂに気密に封着し、内部を真空にした構成を備えている。その他の構成は、実施例２と同一である。
【０１４７】
そうして、本実施例および比較例について、ランプ電圧（Ｖ）、発光効率（ｌｍ／Ｗ）、演色性（平均演色評価数）Ｒａおよび色温度（Ｋ）を測定した結果を表９に示す。なお、比較例は、第２のハロゲン化物に代えて水銀１ｍｇを封入した以外は本実施例と同一である。
【０１４８】
【表９】

本実施例においては、外管内を真空にしたことにより、ランプ電圧が高くなるとともに、発光効率が飛躍的に向上している。これに対して、比較例では若干改善される程度に止まった。
【実施例４】
本実施例は、図２に示す前照灯用短アーク形メタルハライドランプと同じ構造およびサイズにおいて、放電媒体を以下のとおり封入した。
放電媒体：第１のハロゲン化物はヨウ化スカンジウムＳｃＩ_３０．１４ｍｇおよびヨウ化ナトリウムＮａＩ０．７ｍｇ、第２のハロゲン化物はヨウ化亜鉛ＺｎＩ_２０．４ｍｇおよび表１０に示す添加ハロゲン化物０．１ｍｇ、キセノンは５気圧
そうして、本実施例について、ランプ電圧（Ｖ）、発光効率（ｌｍ／Ｗ）、演色性（平均演色評価数）Ｒａおよび色温度（Ｋ）を測定した結果を表１０に示す
。
【表１０】

第２のハロゲン化物は、一般に水銀より蒸気圧が低いが、同一圧力では水銀よりランプ電圧形成に大きく貢献する。
【０１４９】
しかし、水銀は、蒸気圧が常に高いので、移動体の前照灯用などの定格ランプ電力が１００Ｗ以下のような負荷が小さい小形の前照灯用短アーク形メタルハライドランプにおいては、水銀は完全に蒸発する。このため、水銀の封入量によりランプ電圧を調節することができる。
【０１５０】
これに対して、水銀に代えて第２のハロゲン化物を封入する本発明の場合には、封入したハロゲン化物が不完全蒸発の段階で蒸気圧が飽和してしまうため、ランプ電圧はそれ以上増加しない。
【０１５１】
しかしながら、本実施例のように第２のハロゲン化物を複数種封入することでランプ電圧をさらに上昇させることができる。すなわち、第２のハロゲン化物のうち一方のハロゲン化物が飽和したとき、添加した第２のハロゲン化物の蒸発がランプ電圧の増加に貢献する。したがって、第２のハロゲン化物は、１種のときより複数種混合したときの方がランプ電圧を高くすることができる。
【実施例５】
本実施例は、図２に示すものと同じ構造およびサイズにおいて、放電媒体を以下のとおり封入した。
放電媒体：第１のハロゲン化物はヨウ化スカンジウムＳｃＩ_３０．１４ｍｇおよびヨウ化ナトリウムＮａＩ０．７ｍｇ、第２のハロゲン化物は表１１に示すハロゲン化物０．４ｍｇ、第３のハロゲン化物：ヨウ化セシウムＣｓＩ０．１ｍｇ、キセノンは５気圧
また、比較例として、第２のハロゲン化物に代えて水銀１ｍｇを封入した以外は本実施形態と同一仕様のものを製作した。
【０１５２】
そうして、本実施例および比較例について、ランプ入力３５Ｗ一定で点灯して、ランプ電圧（Ｖ）、発光効率（ｌｍ／Ｗ）、演色性（平均演色評価数）Ｒａおよび色温度（Ｋ）を測定した結果を表１１に示す。
【０１５３】
【表１１】

本実施例においては、ヨウ化セシウムＣｓＩを第３のハロゲン化物として添加したことにより、演色性Ｒａおよび色温度は殆ど変わらないが、アークの温度分布が平坦化されるために、熱損失が低下して発光効率が向上する。しかし、水銀を封入した比較例においては、第３のハロゲン化物を添加しても効率向上は見られない。
【０１５４】
また、発光効率の低い水銀の発光がないことにより、発光効率は比較例より高くなる。
【０１５５】
次に、ランプ３において、第３のハロゲン化物のヨウ化セシウムＣｓＩの封入量を変化させた場合の発光効率（ｌｍ／Ｗ）を表１２に示す。
【０１５６】
【表１２】

表１２から、ＣｓＩの添加は０．０１ｍｇから効果がある。反対に、添加量が多すぎると、発光金属の蒸気圧を低くしてしまい効率低下を来す。
【０１５７】
さらに、本実施例について実施例２におけるのと同一条件で瞬時再始動（ホットリスタート）の際の再始動電圧を測定した結果を表１３に示す。
【０１５８】
【表１３】

本実施例においては、水銀を封入している比較例より格段と再始動電圧が低いが、第３のハロゲン化物であるヨウ化セシウムＣｓＩを封入しない場合に較べると、若干再始動電圧が高くなる傾向がある。しかし、実用的には全く問題はない。
【０１５９】
図８は、本発明の前照灯用短アーク形メタルハライドランプの第３の実施形態における発光管を示す正面図である。図において、図２と同一部分については同一符号を付して説明は省略する。
【０１６０】
本実施形態は、直流点灯するように構成している点で異なる。図において、２_Ｋは陰極、２_Ａは陽極である。陰極２_Ｋは相対的に細く、陽極２_Ａは相対的に太い。
【０１６１】
上記構造の前照灯用短アーク形メタルハライドランプの発光管ＩＢを製造するには、まず気密容器１の両端に封止部１ａを形成するための封止管を接合したものを用意する。
【０１６２】
次に、陰極２_Ｋ、モリブデン箔３および外部リード線４の接続組立体を一方の封止管の中に挿入した後、酸水素バーナーを用いて封止管を加熱溶融し、ピンチシールにより封止して陰極２_Ｋを気密容器１に封着する。
【０１６３】
その後、窒素ガス雰囲気中で他方の封止管から第１および第２のハロゲン化物を気密容器１中に封入し、さらに陽極２_Ａ、モリブデン箔３および外部リード線４の接続組立体を封止管内に挿入し、所定の電極間距離４．２ｍｍに設定する。
【０１６４】
さらに、これらの組立体を封止管を介して排気系に装着して気密容器１内を排気し、続いてキセノンを２気圧導入した後、気密容器１を冷却しながら他方の封止管を酸水素バーナーで加熱溶融してからピンチシールにより陽極２_Ａを気密容器１に封着してメタルハライド放電ランプを完成する。以下、本実施形態における実施例６を示す。
【実施例６】
気密容器：包囲部は内径４ｍｍ、長さ７ｍｍの楕円球状、封止部は長さ３０ｍｍ電極 ：陰極２_Ｋは直径０．４ｍｍ、長さ６ｍｍのトリウム入りタングステン棒、陽極２_Ａは、直径０．８ｍｍ、長さ６ｍｍのタングステン棒
封着金属箔：幅１．５ｍｍ、長さ１５ｍｍ、厚さ１５μｍのモリブデン箔
外部リード線：直径０．５ｍｍ、長さ２５ｍｍの導体
放電媒体：第１のハロゲン化物はヨウ化スカンジウムＳｃＩ_３０．１７ｍｇ、ヨウ化ナトリウムＮａＩ０．８３ｍｇ、第２のハロゲン化物はランプ２がＺｎＩ_２０．４ｍｇ、ランプ３がＡｌＩ_３０．２ｍｇ、ランプ４がＦｅＩ_２０．４ｍｇ
比較例（ランプ１）として、第２のハロゲン化物に代えて水銀１ｍｇを封入した以外は本実施例と同一仕様のものを製作した。
【０１６５】
そうして、ランプ２（本実施例）およびランプ１（比較例）について、ランプ入力を定格３５Ｗに対して２０Ｗ、２５Ｗ、３０Ｗおよび３５Ｗで点灯したときの発光効率（ｌｍ／Ｗ）、演色性（平均演色評価数）Ｒａおよび色温度（Ｋ）を測定した結果を表１４に示す。
【０１６６】
【表１４】

図９は、実施例６におけるランプ２の色度特性の立ち上がりを比較例と比較して示す色度図である。図において、曲線Ｅは本実施形態の光束立ち上がりを示す。曲線Ｆは比較例の光束立ち上がりを示す。
【０１６７】
本実施例は、点灯初期から白色領域にある。比較例は、白色領域に入るまで約１分間を要した。
【０１６８】
次に、各ランプについて定格ランプ電力の２０％増しである４２Ｗで６０分間点灯して１５秒消灯の点滅試験を行って気密容器の破裂の有無を調査した結果、いずれも１０００時間経過では破裂したものはなかった。
【０１６９】
さらに、消灯２秒後の瞬時再始動に必要な再始動電圧の測定とを行った結果を表１５に示す。
【０１７０】
【表１５】

図１０は、図８に示す本発明の前照灯用短アーク形メタルハライドランプの第３の実施形態において、希ガスの封入圧力を変化させた場合の光束立ち上がり時間との関係を示すグラフである。図において、横軸はキセノン封入圧力（気圧）を、縦軸は光束立ち上がり時間（秒）を、それぞれ示す。
【０１７１】
図からキセノンの封入圧力が１気圧以上になると、急激に光束立ち上がり時間が短縮して、実用可能になることが分かった。
【０１７２】
図１１は、同じく第３の実施形態において、第２のハロゲン化物としてＺｎＩ_２の封入量（ｍｇ／ｃｃ）を変化させた場合のランプ電圧（Ｖ）の関係を示すグラフである。
【０１７３】
図からＺｎＩ_２を１ｍｇ／ｃｃ以上封入すれば、電子化点灯回路を用いて点灯する場合のランプ電圧の要望値である３０Ｖ以上にできることを理解できる。
【０１７４】
図１２は、本発明のメタルハライドランプ点灯装置の第１の実施形態を示す回路図である。
【０１７５】
本実施形態は、メタルハライドランプを直流点灯するように構成したものである。
【０１７６】
図において、７１は直流電源、７２はチョッパ、７３は制御手段、７４はランプ電流検出手段、７５はランプ電圧検出手段、７６は始動手段、７７はメタルハライドランプである。
【０１７７】
直流電源７１は、バッテリーまたは整流化直流電源が用いられる。移動体の場合には、一般的にバッテリーが用いられる。しかし、交流を整流する整流化直流電源であってもよい。必要に応じて電解コンデンサ７１ａを並列接続して平滑化を行う。
【０１７８】
チョッパ７２は、直流電圧を所要値の電圧に変換するとともに、メタルハライドランプ７７を所要に制御する。直流電源電圧が低い場合には、昇圧チョッパを用い、反対に高い場合には降圧チョッパを用いる。
【０１７９】
制御手段７３は、チョッパ７２を制御する。たとえば、点灯直後にはメタルハライドランプ７７に定格ランプ電流の３倍以上のランプ電流をチョッパ７２から流し、その後時間の経過とともに徐々にランプ電流を絞っていき、やがて定格ランプ電流にするように制御する。
【０１８０】
ランプ電流検出手段７４は、ランプと直列に挿入されてランプ電流を検出して制御手段７３に制御入力する。
【０１８１】
ランプ電圧検出手段７５は、ランプと並列的に接続されてランプ電圧を検出して制御手段７３に制御入力する。
【０１８２】
制御手段７３は、ランプ電流とランプ電圧との検出信号が帰還入力されることにより、定電力制御信号を発生して、チョッパ７２を定電力制御する。また、制御手段７３は、時間的な制御パターンが予め組み込まれたマイコンが内蔵されていて、点灯直後には定格ランプ電流の３倍以上のランプ電流をメタルハライドランプ７７に流し、時間の経過とともにランプ電流を絞るようにチョッパ７２を制御するように構成されている。
【０１８３】
始動手段７６は、始動時に２０ｋＶのパルス電圧をメタルハライドランプ７７に供給できるように構成されている。
【０１８４】
そうして、本実施形態によると、直流点灯しながら点灯直後から所要の光束を発生する。これにより、自動車などの移動体用の前照灯として必要な電源投入後１秒後に定格に対して光束２５％、４秒後に光束８０％の点灯を実現することができる。
【０１８５】
本実施形態の場合、直流−交流変換回路が不要になるため、交流点灯に比較して約３０％コスト低減が可能である。また、重量で１５％軽減できる。これに伴い点灯回路が安価になる。
【０１８６】
図１３は、本発明のメタルハライドランプ点灯装置の第２の実施形態を示す回路図である。図において、図１２と同一部分には同一符号を付して説明は省略する。
【０１８７】
本実施形態は、メタルハライドランプを交流点灯するように構成した点で異なる。
【０１８８】
７８は交流変換手段である。この交流変換手段７８は、フルブリッジインバータからなる。すなわち、一対のスイッチング手段７８ａ、７８ａの直列回路の一対をチョッパ７２の出力端間に並列接続してブリッジ回路を構成し、発振器７８ｂの発振出力を４個のスイッチング手段７８ａの対角方向のスイッチング手段に交互に供給してブリッジ回路の出力端間に高周波交流を発生するものである。
【０１８９】
そして、高周波交流によってメタルハライドランプ７７が点灯されるようになっている。
【０１９０】
この交流点灯形式の構成においても、図１２と同様な制御が行われるようになっている。
【０１９１】
図１４は、本発明の前照灯の第２の実施形態を示す概念図である。
【０１９２】
図１５は、同じく光分配器の部分を示す概念図である。
【０１９３】
図において、８１は点灯回路、８２は光分配器、８３は主幹光ファイバー、８４は光シャッター８５は個別光ファイバー、８６は灯器である。
【０１９４】
点灯回路８１は、図１２または図１３に示す点灯回路を用いることができる。
【０１９５】
光分配器８２は、ケース８２ａ、集光反射面８２ｂ、メタルハライドランプ８２ｃおよび光コネクタ８２ｄを備えている。そして、メタルハライドランプ８２ｃから発生した光を光コネクタ８２ｄの部分から主幹光ファイバー８３に分配する。
【０１９６】
主幹光ファイバー８３は、光分配器８２から分配された光を光シャッター８４に伝送する。
【０１９７】
光シャッター８４は、個別ファイバー８５を介して各灯器８６に選択的に伝送する。
【０１９８】
灯器８６は、ハイビーム灯器８６ａ、ロービーム灯器８６ｂおよびフォグ灯器８６ｃが１組となり、その２組が自動車などの移動体の前部両側に配設される。
【実施例７】
本実施例は、図１４に示す前照灯の第２の実施形態に用いるのに好適な前照灯用短アーク形メタルハライドランプである。
定格ランプ電力：８０Ｗ
電極間距離：２ｍｍ
その他の構造：図２と同様に構成されている。
放電媒体：第１のハロゲン化物はヨウ化スカンジウムＳｃＩ_３０．３ｍｇ、ヨウ化ナトリウムＮａＩ１．５ｍｇ、第２のハロゲン化物はランプ２がＺｎＩ_２１ｍｇ、ＡｌＩ_３１ｍｇ、ＭｎＩ_２１ｍｇ、ランプ３がＺｎＩ_２２ｍｇ、ＧａＩ_３１ｍｇ、ＣｒＩ_２１ｍｇ、キセノンはいずれ も５気圧
また、比較例（ランプ１）として第２のハロゲン化物に代えて水銀１５ｍｇを封入した他は本実施例と同一仕様のものを製作した。
【０１９９】
そうして、本実施例および比較例を定格８０Ｗ一定で点灯してランプ電圧（Ｖ）、発光効率（ｌｍ／Ｗ）、演色性（平均演色評価数）Ｒａおよび色温度（Ｋ）を測定した結果を表１５に示す。
【０２００】
【表１５】

表１５から理解できるように、本実施例においては、水銀を封入する比較例とほぼ同等の特性が得られる。また、図１４に示す前照灯においては、入力を変えて調光する必要が増し、その点で調光が可能であることは極めて有用である。
【０２０１】
【発明の効果】
請求項１の発明によれば、耐火性で透光性の気密容器と、電極間距離が６ｍｍ以下の一対の電極と、第１のハロゲン化物、第２のハロゲン化物ならびに希ガスを含んで気密容器内に封入され、第１のハロゲン化物はナトリウムＮａおよびスカンジウムＳｃを含むハロゲン化物からなり、第２のハロゲン化物は蒸気圧が相対的に大きくて、かつ、第１のハロゲン化物および第２のハロゲン化物が共存している状態でエネルギーが第１のハロゲン化物の金属の発光に集中して第１のハロゲン化物の金属に比較して可視域に発光しにくいために可視域の発光量が少ない金属としてマグネシウムＭｇ、鉄Ｆｅ、コバルトＣｏ、クロムＣｒ、亜鉛Ｚｎ、ニッケルＮｉ、マンガンＭｎ、アルミニウムＡｌ、アンチモンＳｂ、レニウムＲｅおよびガリウムＧａからなるグループの中から選択された金属の一種または複数種で気密容器内容積１ｃｃ当たり１．５ｍｇ超のハロゲン化物からなり、希ガスは１気圧以上で封入されているキセノンである放電媒体とを具備し、本質的に水銀が封入されていないとともに交流および直流のいずれかで点灯するように構成されていることにより、ランプ電圧が水銀を封入したこの種メタルハライドランプとほぼ同様まで高くなり、以下に列挙する効果を奏する前照灯用短アーク形メタルハライドランプを提供することができる。
【０２０２】
１ 始動時の光束立ち上がり特性が良好である。本発明においては、希ガスとしてキセノンを１気圧以上の圧力で封入しているので、上記の色度立ち上がり特性に加えて、始動時から第１の金属ハロゲン化物の発光金属であるスカンジウムＳｃおよびナトリウムＮａが発光して始動時の光束立ち上がり特性を良好にする。また、点灯直後に定格ランプ電流の３倍以上のランプ電流を供給し、時間の経過に伴い電流を低減するように点灯することにより、電源投入後１秒後に定格に対して光束２５％、４秒後に光束８０％の点灯を実現することができる。これに対して、従来の発光金属のハロゲン化物と水銀を封入する前照灯用のメタルハライドランプでは、キセノンの高圧封入と、点灯直後に大電流を流し、徐々に電流を低減させることにより、最初キセノンが発光し、次に水銀が発光して、この水銀の発光が１０〜２０秒後まで続くことで光束立ち上がり特性の問題を解決している。
【０２０３】
２ 始動時の色度立ち上がりが良好である。本発明においては、水銀を本質的に封入していないことにより、始動直後の光束立ち上がり時における発光に主として寄与するのは従来におけるような水銀ではなく、実質的に第１のハロゲン化物を構成する発光金属であるスカンジウムＳｃおよびナトリウムＮａの発光であるから、始動時の色度立ち上がりが良好となる。これに対して、水銀を封入した従来の前照灯用メタルハライドランプでは発明が解決しようとする課題の項で既述のように始動時の発光が主として水銀による発光であるから、光束立ち上がりの問題は解決しているものの色度の立ち上がりが悪いため問題がある。
【０２０４】
３ 白色発光が高い発光効率で得られる。本発明においては、水銀を本質的に封入していないのに加えて、発光効率が水銀より高い発光金属であるスカンジウムＳｃおよびナトリウムＮａのハロゲン化物を第 1 のハロゲン化物として用いることにより、前照灯として必要な白色発光が得られるとともに、発光効率が高くなる。
【０２０５】
４ 反射鏡を用いた光学系において、高い集光効率が得られる。
【０２０６】
５ 瞬時再始動が容易になる。
【０２０７】
６ 調光が可能になる。
【０２０８】
７ 気密容器の点灯中の破裂が少なくなる。
【０２０９】
８ 形状および寸法などのばらつきに対する発光色のばらつきが少ない。
【０２１０】
９ 直流点灯するのにも好適である。
【０２１１】
請求項２の発明によれば、放電媒体は、希ガスが５気圧以上で封入されているキセノンであることにより、始動時の色度の立ち上がり特性および光束立ち上がり特性が一層良好な前照灯用短アーク形メタルハライドランプを提供することができる。
【０２１２】
請求項３の発明によれば、請求項１または２記載の前照灯用短アーク形メタルハライドランプと、前照灯用短アーク形メタルハライドランプを付勢する電子化点灯装置とを具備していることにより、請求項１または２の効果を奏するメタルハライドランプ点灯装置を提供することができる。
【０２１３】
請求項４の発明によれば、反射鏡を備えた前照灯本体と、前照灯本体の反射鏡に発光が入射するように配設される請求項１または２記載の前照灯用短アーク形メタルハライドランプと、前照灯用短アーク形メタルハライドランプを付勢する電子化点灯装置とを具備していることにより、請求項１または２の効果を有する前照灯を提供することができる。
【図面の簡単な説明】
【図１】短アーク形メタルハライドランプにおいて、水銀に代えて第２のハロゲン化物を封入した例および水銀を封入した例におけるそれぞれのアーク温度を示すグラフ
【図２】本発明の前照灯用短アーク形メタルハライドランプの第１の実施形態を示す中央断面正面図
【図３】本発明の前照灯用短アーク形メタルハライドランプの第１の実施形態において、キセノンＸｅの封入圧に対する光束立ち上がり時間の関係を示すグラフ
【図４】同じく第１の実施形態において、第２のハロゲン化物としてヨウ化鉄ＦｅＩ２を用いた場合の封入量に対するランプ電圧の関係を示すグラフ
【図５】本発明の前照灯用短アーク形メタルハライドランプの第２の実施形態を示す正面図
【図６】本発明の前照灯の第１の実施形態を示す斜視図
【図７】本発明の実施例２における表５のランプ２および比較例であるランプ１の色度の変化を示す色度図
【図８】本発明の前照灯用短アーク形メタルハライドランプの第３の実施形態を示す正面図
【図９】実施例６におけるランプ２の色度特性の立ち上がりを比較例と比較して示す色度図
【図１０】図８に示す本発明の前照灯用短アーク形メタルハライドランプの第３の実施形態において、希ガスの封入圧力を変化させた場合の光束立ち上がり時間との関係を示すグラフ
【図１１】同じく第３の実施形態において、第２のハロゲン化物としてＺｎＩ_２の封入量（ｍｇ／ｃｃ）を変化させた場合のランプ電圧（Ｖ）の関係を示すグラフ
【図１２】本発明のメタルハライドランプ点灯装置の第１の実施形態を示す回路図
【図１３】本発明のメタルハライドランプ点灯装置の第２の実施形態を示す回路図
【図１４】本発明の前照灯の第２の実施形態を示す概念図
【図１５】同じく光分配器の部分を示す概念図
【図１６】メタルハライドランプにおけるランプ電圧を説明するための概念図
【図１７】従来の投光用の短アーク形メタルハライドランプの発光スペクトル分布を示すグラフ
【符号の説明】
１…気密容器
１ａ…包囲部
１ｂ…封止部
２…電極
２ａ…電極軸
３…封着金属箔
４…外部リード線
ＩＢ…発光管
ＩＴ…絶縁チューブ
ＯＢ…外管[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a short arc type metal halide lamp for a headlamp, a metal halide lamp lighting device including the same, and a headlamp.
[0002]
[Prior art]
A metal halide lamp in which a rare gas, a halide of a luminescent metal, and mercury are sealed in an arc tube having a pair of electrodes facing each other is widely used because of its relatively high efficiency and high color rendering. As is well known, metal halide lamps include a short arc type and a long arc type.
[0003]
The short arc type metal halide lamp is used for light projection such as a liquid crystal projector and an overhead projector for condensing the light emitted from the lamp and projecting it on a screen, and for store lighting such as a downlight and a spotlight. In addition, in the field of floodlights, small short arc metal halide lamps have recently been used in place of halogen bulbs for automotive headlamps. The specification of a metal halide lamp for automobile headlamps is described in, for example, Japanese Patent Application Laid-Open No. 2-7347, but it is indispensable to enclose about 2 to 15 mg of mercury.
[0004]
By the way, there is a need for a metal halide lamp that does not require mercury encapsulation. For example, an invention described in Japanese Patent Application Laid-Open No. 3-1112045 has been made. In the present invention, helium or neon is sealed in place of mercury at a pressure of 100 to 300 Torr to obtain a required lamp voltage. Further, since these rare gases have a small atomic radius, quartz glass is used. Then, since it permeate | transmits, it is the structure of forming an airtight container with translucent ceramics.
[0005]
However, metal halide lamps currently in practical use require mercury in order to obtain a desired lamp voltage and maintain electrical characteristics. That is, for example, if the lamp voltage is low, the lamp current must be increased to obtain the desired lamp input. In this case, an increase in current capacity and an increase in generated heat of related equipment such as a lighting circuit, a luminaire, and wiring become problems. In addition, when the lamp current is large, there is a problem that the lamp efficiency is lowered with an increase in electrode loss. That is, since the electrode drop voltage of a metal halide lamp is constant depending on the lamp, if the lamp voltage is low, it is necessary to increase the lamp current to compensate for this, so the electrode loss increases in proportion to the lamp current and the lamp efficiency increases. It will decline. Therefore, in general, in a discharge lamp, it is advantageous to set the lamp voltage as close as possible to the lamp input voltage, that is, as high as possible within a range where the arc does not go out.
[0006]
Next, the reason why the mercury sealing is necessary will be described while considering the lamp voltage.
[0007]
FIG. 16 is a conceptual diagram for explaining a lamp voltage in a metal halide lamp.
[0008]
In the figure, 1 is an airtight container, 2 and 2 are electrodes, and 3 and 3 are lead wires.
[0009]
The lamp voltage Vl is a voltage appearing between the lead wires 3 and 3 in the lighting state of the metal halide lamp. A distance L between the electrodes 2 and 2 is referred to as an interelectrode distance.
[0010]
The lamp voltage Vl can be expressed by Equation 1.
[0011]
[Expression 1]
Vl = E × L + Vd
Here, E is the potential gradient of the plasma between the electrodes, and Vd is the electrode drop voltage.
[0012]
The plasma potential gradient E can be expressed by Equation 2.
[0013]
[Expression 2]
E = I / 2π∫σr dr
Here, I is the lamp current, σ is the electrical conductivity of the plasma, and is a function of the temperature T. r is a radial distance from the center to an arbitrary position.
[0014]
Assuming that the substance A exists in the discharge space during the lighting of the metal halide lamp, the electrical conductivity σ at the temperature T of the substance A can be expressed by Equation 3.
[0015]
[Equation 3]
σ = C · N_E/ (T^1/2・ (N_A・ Q))
Where C is a constant, N_EIs the electron density, N_AIs the density of the material, and Q is the collision cross section of the electron against the material A.
[0016]
It can be seen from Equation 1 that the ramp voltage Vl increases as the potential gradient E increases and the interelectrode distance L increases. Further, it can be seen from Equation 2 that the potential gradient E increases as the electrical conductivity σ decreases and the lamp current I increases. Furthermore, the electrical conductivity σ is calculated from Equation 3 as N_EIs smaller, N_AIt can be seen that the smaller Q and Q are, the smaller it becomes.
[0017]
Therefore, when the interelectrode distance L and the lamp current I are constant, the condition of the substance A that increases the lamp voltage Vl is less likely to be ionized (N_ECan be kept small. ) The density in the lamp is large (N_ACan be increased. ), The collision cross-sectional area Q with electrons is large.
[0018]
Thus, mercury is a substance that has a very high vapor pressure (1 atm at 361 ° C.), is difficult to ionize, and has a large cross-sectional area of collision with electrons. Therefore, a desired lamp voltage can be easily obtained by adjusting the amount of mercury enclosed according to the lamp size.
[0019]
From the above description, it can be understood why a desired lamp voltage can be easily obtained by using mercury in a conventional metal halide lamp.
[0020]
[Problems to be solved by the invention]
By the way, in the case of a metal halide lamp, it is necessary to increase the vapor pressure of mercury in order to ensure a required lamp voltage as the distance between the electrodes is smaller and shorter. For example, in a small short arc type metal halide lamp having an arc tube with an internal volume of 1 cc or less, the mercury vapor pressure during lighting becomes 20 atm or more. A metal halide lamp with a rated lamp power of 100 W or less for a headlamp of a moving body such as an automobile has a feature that a distance between electrodes is small and a load on a tube wall is large. For this reason, in the case of a conventional metal halide lamp enclosing mercury, the mercury vapor pressure becomes a high pressure of 20 atmospheres or more in order to obtain a required lamp voltage as described above, and the airtight container is relatively moved accordingly. Easy to break.
[0021]
In addition, since xenon is sealed at a high pressure because it is necessary to improve the luminous flux rise characteristic, the xenon during lighting becomes about 35 atm. For this reason, it is necessary to apply a starting pulse voltage having a high voltage and a large power in order to start the starting gas with dielectric breakdown. At the time of instantaneous restart, a higher starting pulse voltage is required. Therefore, the lighting circuit, the luminaire, and the wiring must have a dielectric strength grade that is appropriate, and is therefore expensive.
[0022]
Furthermore, the problem of the rising characteristics of the luminous flux has been solved by the high-pressure encapsulation of xenon and the application of a high starting pulse voltage and a means of flowing a large current immediately after lighting and gradually reducing the current, but the chromaticity rising characteristics have been solved. Is bad. That is, xenon emits light first, followed by mercury. This mercury emission continues until 10 to 20 seconds later. Mercury emission is poor in color rendering and does not fall within the required white range.
[0023]
In the following, the short arc type metal halide lamp for headlamps is divided into the problem of enclosing mercury and the problem in the case of not enclosing mercury in the prior art.
1 Problems caused by encapsulating mercury
(1) Problems with environmentally hazardous substances
At present, environmental issues are very close up on a global scale. In the lighting field, it is very important to reduce mercury from the lamp, which is an environmentally hazardous substance that has a negative impact on the environment, and even to eliminate it. It is considered a serious problem.
[0024]
Therefore, the biggest problem of the conventional metal halide lamp is that mercury is enclosed.
[0025]
(2) Problem of rising chromaticity characteristics at start-up
In the case of a short arc type metal halide lamp for an automotive headlamp, an instantaneous rise of a luminous flux is required. For this reason, the conventional short arc type metal halide lamp for headlamps uses a lighting method in which xenon is sealed at a high pressure as a starting gas, a large current is passed at the beginning of lighting, and the current is reduced over time. Has been. In this way, an instantaneous rise is possible, but when the switch is turned on, mercury rapidly evaporates and takes energy away, so the vapor pressure of the luminescent metal rises slowly, so that a strong mercury emission state is 10 to 10. Continue until 20 seconds later. Mercury luminescence is inferior in color characteristics, so color rendering is poor and chromaticity does not fall within the white range. Thus, the rise of chromaticity characteristics is very bad. Therefore, it takes a long time before the light emission having the desired chromaticity characteristic is obtained.
[0026]
(3) Problems unsuitable for dimming
When the temperature of the arc tube changes, the color temperature of light emission changes greatly, and the color rendering properties change accordingly. Hereinafter, this problem will be described with reference to FIG.
[0027]
FIG. 17 is a graph showing an emission spectrum distribution of a conventional short arc type metal halide lamp for light projection. In the figure, the horizontal axis represents wavelength (nm), and the vertical axis represents relative radiation power (%).
[0028]
This conventional short arc type metal halide lamp is composed of argon 500 Torr as a rare gas and dysprosium iodide DyI as a halide.₃1 mg and neodymium iodide NdI₃1 mg as well as 13 mg of mercury. The emission spectrum is composed of continuous emission by dysprosium and neodymium and main emission line spectra by elements each having a symbol on the arrow, and it can be seen that the emission line spectrum by mercury has a large power.
[0029]
By the way, the amount of light emitted by each light emitting metal changes in proportion to the vapor pressure in the lamp. The vapor pressure of the halide of the luminescent metal is significantly lower than that of mercury. Therefore, if the temperature of the arc tube changes, the vapor pressure of the luminescent metal changes due to the change in the evaporation amount of the halide. The amount of luminescence changes.
[0030]
  On the other hand, since the vapor pressure of mercury is very high, it does not change so much even if the temperature of the arc tube changes, so the amount of light emitted by the strong emission line spectrum of mercury does not change much.
Therefore, when the input power to the arc tube is reduced, light emission by mercury is relatively dominant, so that the color temperature of light emission is lowered and the color rendering properties are lowered. This is the conventional metal halide that encloses mercurylampMeans not suitable for dimming.
[0031]
In the case of automotive headlamps, dimming is necessary for daylighting (daylighting) used in Europe and the United States, but conventional metal halide lamps that contain mercury have color characteristics. It will drop significantly.
[0032]
(4) Problems with large variations in characteristics
Mercury-encapsulated metal halides tend to vary in characteristics even with the same input because the temperature of the arc tube varies with the dimensional variations of individual lamps. In addition, the characteristics are likely to change due to an increase in the coldest part temperature due to blackening of the arc tube during the long life.
[0033]
(5) Problems that make instant restart difficult
In the short arc type metal halide lamp for headlamps, as described above, high-pressure xenon is enclosed in order to speed up the rise of the luminous flux, and the xenon is about 35 atm during lighting. Thus, since the mercury vapor pressure and the xenon vapor pressure during lighting are very high, in order to restart, a very high and high power pulse voltage must be applied. This not only makes the lighting circuit expensive, but also requires that the lighting circuit, the lamp, and the appliance that houses them be insulated from high voltages.
[0034]
Further, in a small short arc type metal halide lamp, since the distance between the electrodes is small, the mercury vapor pressure is set high in order to obtain a required lamp voltage, and the mercury vapor pressure becomes 20 atm or more during lighting.
[0035]
(6) Problem that arc tube is easy to burst
As described above, since the mercury vapor pressure at the time of lighting is high, the arc tube is easily ruptured due to the initial distortion or the distortion increasing during long-term lighting. This problem significantly reduces lamp reliability.
[0036]
(7) The problem of low illuminance on the irradiated surface
In the case of a short arc type metal halide lamp for headlamps, it is important how light emitted from the lamp reaches the irradiation surface via an optical system without losing light when the irradiation surface at a separated position is illuminated brightly. As has been found by the present invention, it is necessary to narrow the arc in order to reduce the loss and improve the illuminance of the irradiated surface. The fact that the arc is constricted means that the arc temperature distribution is steep.
[0037]
However, mercury emission is absorbed and optically thick, and the temperature rises due to absorption of energy in the middle and low temperature parts, so the arc temperature distribution spreads in a parabolic shape, thus constricting the arc. I can't.
[0038]
On the other hand, when scandium or rare earth metal is used as the light emitting metal and the light emission is greatly increased, it is known that the arc can be narrowed down even in the presence of mercury. However, since the lighting pressure of mercury is high, the convection becomes intense and the instability of the arc occurs, which cannot be put to practical use.
2 Problems with conventional technology that does not contain mercury
In the above-described metal halide lamp that does not enclose mercury, helium or neon has a remarkably high pressure during operation. Therefore, if it is made to withstand this, a metal halide lamp that does not enclose mercury can be obtained. Therefore, it can be evaluated in many respects in that a metal halide lamp that does not enclose mercury can be obtained.
[0039]
However, it is quite difficult to realize a structure similar to that of a conventional metal halide lamp in which mercury is sealed at a high pressure during lighting. For example, in a small metal halide lamp, if the required lamp voltage is 50 to 60 V, the pressure of helium or neon during lighting will exceed 150 atm. High reliability cannot be obtained.
[0040]
  The present invention does not essentially use mercury, which has a large environmental impact, and has almost the same electrical and light emission characteristics as those encapsulating mercury, and has a good rise in luminous flux at start-up.NaIt is an object of the present invention to provide a short arc type metal halide lamp for a headlamp, a metal halide lamp lighting device including the same, and a headlamp.
[0041]
  In addition, the present invention essentially does not use mercury with a large environmental load, and has approximately the same electrical characteristics and light emission characteristics as those enclosing mercury,Condensing efficiency is high,Good rise in chromaticity at startupIt is easy to restart instantly, can be dimmed, the hermetic container is hard to rupture, and there is little variation in characteristicsAnother object of the present invention is to provide a short arc type metal halide lamp for a headlamp, a metal halide lamp lighting device including the same, and a headlamp.
[0042]
[Means for achieving the object]
    A short arc type metal halide lamp for a headlamp according to a first aspect of the present invention includes a fireproof and translucent airtight container; a pair of electrodes sealed in the airtight container and having an interelectrode distance of 6 mm or less; 1 halide, 2nd halide, and a rare gas are enclosed in an airtight container. The 1st halide is composed of a halide containing sodium Na and scandium Sc, and the 2nd halide has a vapor pressure. Compared to the metal of the first halide, which is relatively large and the energy concentrates on the light emission of the metal of the first halide in the state where the first halide and the second halide coexist. Therefore, magnesium Mg, iron Fe, cobalt Co, chromium Cr, zinc Zn, nickel Ni, manganese Mn, aluminum Miniumu Al, antimony Sb, rhenium ReandOne or more types selected from the group consisting of gallium Ga per 1 cc of the volume in the hermetic containerOver 1.5mgFrom the halides ofThe rare gas is xenon sealed at 1 atm or higher.A discharge medium that is essentially not encapsulated with mercury and is lit with either alternating current or direct current.
[0043]
In the present invention and each of the following inventions, terms and technical meanings are as follows unless otherwise specified.
[0044]
  <About airtight containers>
  In the present invention, the hermetic container must be fireproof and translucent. The internal volume is suitable for headlamps and as a short arc type metal halide lamp.ToThe In addition, the airtight container being “fireproof and translucent” is a material having fire resistance that can sufficiently withstand the normal operating temperature of the discharge lamp, and visible light in a desired wavelength region generated by discharge is externally applied. As long as it can be derived, it may be made of anything. For example, quartz glass, translucent alumina, ceramics such as YAG, or single crystals thereof can be used. If necessary, it is allowed to form a halogen-resistant or metal-resistant transparent coating on the inner surface of the hermetic container or to modify the inner surface of the hermetic container.
[0045]
In addition, the airtight container preferably has a maximum diameter portion of 3 to 10 mm inside diameter and 5 to 13 mm outside diameter.
[0046]
<About a pair of electrodes>
The pair of electrodes constitutes a short arc type structure in which the distance between the electrodes is 6 mm or less. And it is sealed and opposed to the inside of the airtight container. The “short arc type” is a distance between electrodes formed in the hermetic container, and can be a so-called stable electrode type in which arc discharge is stabilized by an electrode. For this reason, when the short arc shape is used, the distance between the electrodes is small, so that the light emitted from the discharge lamp can be brought as close to the point light source as possible, and the light can be efficiently collected by an optical system such as a reflecting mirror or a lens. When the distance between the electrodes exceeds 6 mm, the distance from the point light source is increased, the light condensing property by a reflecting mirror or the like is deteriorated, and the illuminance on the irradiated surface is lowered. The distance between the electrodes is preferably 1 to 5 mm, more preferably 4 mm or less, and most preferably 1 to 3 mm. The distance between the electrodes is measured at the tip of the electrode.
[0047]
Moreover, the short arc type metal halide lamp for headlamps of the present invention is either AC or DC.OrConfigure to light atHas been. Therefore, a pair of electrodes have the same structure when operated with an alternating current, but when operated with a direct current, the anode generally has a significant temperature rise, so that a heat radiation area larger than that of the cathode and therefore a main part should be used. Can do.
[0048]
<Discharge medium>
In the present invention, the discharge medium essentially contains the first halide, the second halide and the noble gas as described above.
[0049]
    (About the first halide)
  The first halide is a metal halide that generates visible light and contains sodium Na and scandium Sc as main components. In general, these first halides do not necessarily have a relatively high vapor pressure during lighting.
[0050]
In addition, the first halide is allowed to contain a rare earth metal halide or the like as an accessory component in addition to sodium Na and scandium Sc, if necessary.
[0051]
    (About the second halide)
  The second halide has a relatively high vapor pressure during lighting, and the first halide and the second halide coexist in a state where the energy of the first halide metal is emitted. It is a metal that emits less light in the visible region because it is less likely to emit light in the visible region than the first halide metal, specifically magnesium Mg, iron Fe, cobalt Co, chromium Cr, Zinc Zn, Nickel Ni, Manganese Mn, Aluminum Al, Antimony Sb, Rhenium ReandIt is a metal selected from the group consisting of gallium Ga. Note that “the vapor pressure is high” does not need to be too high like mercury, and preferably the pressure in the airtight container during lighting is about 5 atm or less. The phrase “difficult to emit light in the visible range compared to the metal of the first halide” does not mean that visible light is less emitted in an absolute sense, but a relative meaning. For sure, Fe and Ni emit more in the ultraviolet region than in the visible region, but Ti, Al, Zn and the like emit more in the visible region. Therefore, when these metals that emit a lot of light in the visible region are caused to emit light alone, energy is concentrated on the metal, so that there is a lot of light in the visible region. However, since the energy of the second halide metal is higher than that of the first halide metal, the energy of the first halide is the same as that of the first halide in the state where the first and second halides coexist. This is because the light emitted from the metal constituting the second halide is reduced because it concentrates on the light emitted from the metal.
[0052]
  Among the above groups, the second halide is iron Fe, zinc Zn, manganese Mn, aluminum AlandOne or more halides selected from the group consisting of gallium Ga are particularly preferred. However, these metals are optimally used as the main component, but magnesium Mg, cobalt Co, chromium Cr, nickel Ni, antimony SbandThe lamp voltage can be further increased by adding one or more selected from the group of rhenium Re as a subcomponent.
[0053]
Table 1 illustrates a second halide that is effective in the practice of this invention, along with a temperature of 1 atmosphere. Note that these values differ somewhat depending on the literature, and therefore the temperature values in Table 1 are approximate values.
[0054]
[Table 1]
        No. Second halide Temperature at 1 atm (° C)
          1 AlI₃                    422
          2 FeI₂                    827
          3 ZnI₂                    727
          4 SbI₃                    427
          5 MnI₂                    827
          6 CrI₂                    827
          7 GaI₃                    349
          8 ReI₃                    627
          9 MgI₂                    927
        10 CoI₂                    827
        11 NiI₂                    747
  Most of the halides shown in Table 1 have a vapor pressure lower than that of mercury and the adjustment range of the lamp voltage is narrower than that of mercury. The range can be expanded. For example, AlI₃Is in an incompletely evaporated state and the desired lamp voltage is not obtained, AlI₃Even if is added, the lamp voltage does not change. In contrast, AlI₃Instead of ZnI₂When ZnI is added₂Since the lamp voltage corresponding to the above is added, the lamp voltage can be increased. Furthermore, if another second halide is added, a higher lamp voltage can be obtained.
[0055]
Further, the second halide is not prohibited from emitting visible light, and is allowed as long as the ratio to the total visible light emitted by the discharge lamp is small and has little influence.
[0056]
  Further, in the present invention, the second halide is contained per 1 cc of the internal volume of the hermetic container.Over 1.5mgIt is enclosed. Preferably,Over 1.5mg~ 200 mg.
[0057]
(About halogen)
As the halogen constituting the first and second halides, iodine is optimal in reactivity, and the reactivity increases in the order of bromine, chlorine, and fluorine. Good. In addition, different halogen compounds such as iodide and bromide can be used in combination.
[0058]
    (About rare gas)
  The rare gas is a gas that acts as a starting gas and a buffer gas, and is enclosed in an airtight container. Use one or more xenon, argon, or krypton as the rare gas.Alsoit canBut,In the present inventionUsing xenon as a rare gas, the sealing pressure is increased to 1 atmosphere or more.BecauseFurther, it is possible to improve the luminous flux rising characteristics of the metal halide lamp. The good luminous rise characteristicsLike the present inventionHeadlights for moving objects such as automobilesforIs extremely important. The enclosed pressure of xenon is preferably 1 to 15 atmospheres.
[0059]
    (About mercury)
  In the present invention, “essentially mercury is not enclosed”Even if mercury is enclosedLess than 0.3mg per 1cc of internal volume of airtight container(Preferably 0.2 mg or less)It means that. However, it is environmentally desirable not to enclose mercury at all.From the above, the above definition includes a state in which no mercury is enclosed. In the case of maintaining the electrical characteristics of the discharge lamp with mercury vapor as in the conventional case, the short arc type is sealed because 20 mg or more per 1 cc of the internal volume of the hermetic container, and the long arc type is also filled with 5 mg or more. Thus, it can be said that the present invention is essentially free of mercury.
[0060]
<Other configuration>
Although not an essential component of the present invention, the following components can be added as necessary.
[0061]
About 1 outer pipe
The outer tube houses the arc tube therein. If necessary, the inside of the outer tube can be evacuated. As a result, the heat loss of the hermetic container can be further reduced to improve the light emission efficiency, and the light emission efficiency can be further increased as compared with a conventional mercury-encapsulated product.
[0062]
About 2 heat insulation means
The heat retaining means is a means for reducing the loss of heat generated from the arc tube, and may have any configuration as long as the loss of heat generated from the arc tube can be reduced. It is allowed to have a configuration such as
[0063]
By evacuating the inside of the outer tube, heat loss due to convection and conduction of heat generated from the arc tube is reduced, and the discharge medium is kept warm. In this case, the specific structure, shape, and constituent materials are not limited. Note that the vacuum in the outer tube means that the pressure in the outer tube is 10 Torr or less.
[0064]
In addition, it reflects the heat rays radiated from the arc tube to the outside and returns them to the arc tube, and has a heat ray reflective / visible light transmissive film that transmits visible light, thereby reducing heat loss due to radiation and keeping the discharge medium warm. can do. The heat reflecting / visible light transmitting film is formed on a cylindrical body made of quartz glass or the like disposed between the arc tube and the outer tube, the inner surface, the outer surface, the inner or outer surface of the outer tube, or formed on the outer surface of the arc tube. be able to.
[0065]
Furthermore, it goes without saying that the above-mentioned means can be combined appropriately.
[0066]
And since it has heat insulation means to reduce the heat loss generated from the arc tube, the heat loss generated by the discharge inside the arc tube is small, so the heat loss of the arc tube is reduced and the luminous efficiency Will improve.
[0067]
3 Lamp power
Since the lamp power is for headlamps, the power is preferably 100 W or less.
[0068]
  <About the effect | action of this invention>
  As is apparent from the above description, the present inventionShort arc metal halide lamps for headlightsIn addition to the first halide which is a metal halide that generates visible light containing sodium Na and scandium Sc as main components, the vapor pressure is relatively high and the first halide and the second halide In the state where two halides coexist, the energy concentrates on the light emission of the metal of the first halide and it is difficult to emit light in the visible region compared to the metal of the first halide. Magnesium Mg, iron Fe, cobalt Co, chromium Cr, zinc Zn, nickel Ni, manganese Mn, aluminum Al, antimony Sb, rhenium ReandA halide of a metal selected from the group consisting of gallium GaOver 1.5mg per 1cc of internal volume of airtight containerAs the second halide, it is essentially sealed instead of mercury.In addition, xenon as a rare gas is sealed at 1 atm or more. Thus, in the present inventionThe lamp voltage isIt is almost as high as this type of metal halide lamp that contains mercury,It is mainly determined by the evaporation amount of the second halide. When the second halide is incompletely evaporated, the amount of evaporation is determined by the vapor pressure of the second halide. The vapor pressure of the halide is determined by the coldest part temperature. The second halide has a vapor pressure during lighting that is lower than that of mercury, but is clearly higher than that of the first halide, and may be about 5 atm or less.
[0069]
Therefore, the short arc type metal halide lamp for headlamps according to the present invention operates as desired without essentially enclosing mercury, and the lamp voltage has substantially the same electrical characteristics and light emission as the prior art in which mercury is encapsulated. Characteristics can be obtained. Here, “substantially” means that there is a difference that is somewhat inferior within a practical range as compared with the prior art. This is also in a practically acceptable range, considering that the short arc type metal halide discharge lamp for headlamps is lit by an electronic lighting device. However, the lamp voltage can be further increased by applying a heat retaining means to the airtight container as desired.
[0070]
Based on the above operations, the following specific effects are obtained. For this reason, the short arc type metal halide lamp for headlamps of the present invention is optimal for headlamps of moving bodies such as automobiles.
[0071]
  1It is possible to improve the luminous flux rising characteristic at the time of starting.
[0072]
  In the present invention, since xenon is enclosed as a rare gas at a pressure of 1 atm or higher, in addition to the chromaticity rising characteristics described later, scandium Sc and sodium, which are the luminescent metals of the first metal halide from the start, are used. Na emits light and the luminous flux rising characteristics at the start are good. Further, by supplying a lamp current more than three times the rated lamp current immediately after lighting and lighting so as to reduce the current as time elapses, a luminous flux of 25% with respect to the rating is obtained 4 seconds after the power is turned on. It is possible to realize lighting with 80% luminous flux after 2 seconds. On the other hand, in a conventional metal halide lamp for a headlamp that encloses a luminescent metal halide and mercury, a high current encapsulated xenon and a large current flow immediately after lighting, gradually reducing the current, Xenon emits light, then mercury emits, and this mercury emission lasts until 10 to 20 seconds, thereby solving the problem of the rising characteristics of light flux.
[0073]
  2  Good rise in chromaticity at start-up.
[0074]
  In the present invention, since mercury is not essentially enclosed, it is not mercury as in the prior art that substantially contributes to light emission at the time of rising of the light beam immediately after starting, but substantially constitutes the first halide. Since it is light emission of scandium Sc and sodium Na which are light emitting metals, the chromaticity rise at the time of starting becomes favorable. On the other hand, in the conventional metal halide lamp for headlamps in which mercury is enclosed, as described above in the section of the problem to be solved by the invention, light emission at start-up is mainly light emission from mercury, so that there is a problem of rising of luminous flux. Is solved, but there is a problem because the rise of chromaticity is bad.
[0075]
  3  White light emission can be obtained with high luminous efficiency.
[0076]
  In the present invention, in addition to essentially not containing mercury, scandium Sc and sodium Na halides, which are luminescent metals having a luminous efficiency higher than mercury, are added. 1 When used as a halide, the white light emission necessary for a headlamp can be obtained and the luminous efficiency is increased.
[0077]
  4  In an optical system using a reflecting mirror, high light collection efficiency can be obtained.
[0078]
  The short arc metal halide lamp for headlamps of the present invention has surprisingly been found to have extremely high light collection efficiency when combined with an optical system using a reflecting mirror. The reason is that when the second halide is enclosed instead of mercury, the arc is effectively reduced as shown in FIG.
[0079]
    FIG. 1 is a graph showing respective arc temperatures in an example in which a second halide is enclosed instead of mercury and an example in which mercury is enclosed in a short arc type metal halide lamp. In the figure, the horizontal axis indicates the radial position in the central section between the electrodes of the hermetic container, and the vertical axis indicates the arc temperature (K). In the figure, curve A shows an example in which a second halide is enclosed instead of mercury, and curve B shows an example in which mercury is enclosed. In addition, the example of the curve A shows dysprosium iodide DyI as the first halide. ₃ 1 mg and neodymium iodide NdI ₃ 1 mg AlI as the second halide ₃ In this example, 8 mg is enclosed in a spheroidal airtight container having an inner diameter of 14 mm together with argon 500 Torr. The example of curve B has the same specifications as the former except that 13 mg of mercury is enclosed instead of the second halide. It can be seen that the curve A is narrower than the curve B.
[0080]
  For this reason, when the short arc type metal halide lamp for headlamps of the present invention is used as the light source of the headlamps, the illumination intensity on the irradiated surface can be remarkably improved.
[0081]
  5Instant restart is easy.
[0082]
  In the present invention, the vapor pressure of the second halide is clearly lower in most cases compared to mercury, facilitating instant restart. For this reason, since the peak value of the starting pulse voltage applied for restarting can be reduced, it is possible to reduce the dielectric strength of the electronic lighting device, the starting device, the wiring, and the lighting fixture and to reduce the cost.
[0083]
  6Dimming is possible.
[0084]
  Even when the input to the lamp changes, the light emission color temperature and the color rendering properties change little, so that dimming is possible. Therefore, lighting during the day (daylight) becomes possible.
[0085]
  7Less bursting during lighting of the airtight container.
[0086]
  In the present invention, the vapor pressure during lighting does not become extremely high, and it is easy to reduce it to about 60% at the time of mercury filling, so that the bursting during lighting of the airtight container is reduced.
[0087]
  8There is little variation in emission color with respect to variations in shape and dimensions.
[0088]
  Since the change in lamp characteristics with respect to variations in the shape and dimensions of the arc tube is small, the variation in emission color is small.
[0089]
9 Suitable for direct current lighting.
[0090]
When a conventional metal halide discharge lamp enclosing mercury is dc-lit, luminescent metals such as sodium Na and scandium Sc are positively ionized and are therefore attracted to the cathode side, and the anode side has a concentration of the luminescent metal compared to the cathode side. Becomes smaller. On the other hand, some mercury is also attracted to the cathode side, but since the amount of mercury is overwhelmingly large, a sufficient amount of mercury is also present on the anode side. As a result, the light emitting metal emits sufficient light on the cathode side, but the light emission of the light emitting metal is significantly weakened on the anode side, and the light emission of mercury is mainly performed. For this reason, remarkable color separation is caused between the electrodes, which is not suitable for practical use. Therefore, in an application field where color separation is a problem, metal halide discharge lamps containing mercury are exclusively used by alternating current lighting.
[0091]
On the other hand, in the present invention, the difference in color temperature between the electrodes is small enough even when direct current lighting is performed by enclosing the second halide instead of essentially enclosing mercury. Can be used practically. This is because the second halide hardly emits light in the visible range, and therefore the metal of the first halide emits light strongly even on the anode side.
[0092]
    The short arc type metal halide lamp for headlamps of the invention of claim 2 is the short arc type metal halide lamp for headlamps of claim 1, wherein the discharge medium is a rare gas.5It is characterized by being xenon enclosed at or above atmospheric pressure.
[0093]
  In the present invention, the rising characteristic of chromaticity at the start isOne layerIt is a good short arc metal halide lamp for headlamps. That is, by encapsulating the second halide, in addition to essentially not encapsulating mercury, the first halide as the luminescent material is a halide containing sodium Na and scandium Sc, and a rare gas Xenon as5It has the structural feature that it is sealed above atmospheric pressure.
[0094]
  Thus, the metal halide lamp of the present invention isSince xenon is sealed at 5 atmospheres or more, the luminous flux rise characteristic is further improved.First halide luminescent metal from start-upSodium and scandium Sc asEmits light, so the chromaticity is almost the same as the startIn other words, from the rise of the luminous fluxWhite light chromaticity specified in the standard of metal halide lamps for headlamps (Japanese Industrial Standards JIS
D 5500-1984, which falls within the range of the white chromaticity range described in the description of automotive lamps. For this reason, there is no sense of incongruity in light emission.
[0095]
  On the other hand, in the case of a conventional short arc type metal halide lamp for headlamps in which mercury is enclosed, the light emission for 10 to 20 seconds at the start is mainly mercury light emission,That is, the rising of the light beam immediately after starting is performed by the emission of mercury.For,The color rendering properties are poor, and the chromaticity greatly deviates from the above chromaticity range.
[0096]
  In addition, according to the present invention, xenon is5Because it is sealed at a pressure higher than atmospheric pressure, the luminous flux rise characteristics at the startOne layerCan be good.
[0097]
A metal halide lamp lighting device according to a third aspect of the present invention is a short arc type metal halide lamp for a headlamp according to claim 1 or 2; an electronic lighting device for energizing a short arc type metal halide lamp for a headlamp; It is characterized by having.
[0098]
The electronic lighting device is configured to output alternating current when the short arc type metal halide lamp for headlamps is turned on, and to output direct current when turned on by direct current.
[0099]
In the case of AC lighting, the electronic lighting device is configured to convert a direct current of a battery power source or a direct current obtained by rectifying an alternating current of a commercial frequency into a high frequency alternating current, and then supply it to a short arc type metal halide lamp for a headlamp. Is common.
[0100]
On the other hand, in the case of direct current lighting, it is not necessary to convert to high frequency alternating current. For this reason, the circuit configuration of the electronic lighting device can be simplified to be small, light, and inexpensive. That is, since a moving body such as an automobile is generally equipped with a battery power source as described above, the direct current is converted into alternating current and then supplied to a short arc metal halide lamp for a headlamp to be lit. The circuit configuration of the lighting device is simplified by using. Even when a control means such as a step-up chopper or a step-down chopper is used to set the direct current to a desired voltage, the above effects are not substantially changed. This is because the control means is used when necessary even in the case of AC lighting. The reason why direct current lighting is possible in this way is that the color separation becomes practically acceptable without enclosing mercury.
[0101]
Also, the electronic lighting device is configured to supply a current more than three times the rated lamp current immediately after the short arc type metal halide lamp for headlamps is turned on, and to reduce the current with the passage of time. be able to. If it does so, the metal halide lamp lighting device which satisfies the light beam rise characteristic requested | required for the headlamps of a moving body is obtained. In this case, the lighting may be either AC lighting or DC lighting.
[0102]
Claim4The headlamp body of the present invention comprises: a headlamp body provided with a reflecting mirror; and the short arc for headlamps according to claim 1 or 2, wherein the headlamp body is arranged so that light is incident on the reflecting mirror of the headlamp body. And a computerized lighting device for energizing a short arc type metal halide lamp for a headlamp.
[0103]
The “headlamp main body” refers to the remaining portion of the headlamp excluding the headlight short arc metal halide lamp and the electronic lighting device. A reflecting mirror and a front cover are provided.
[0104]
The short arc type metal halide lamp for headlamps is disposed at a predetermined position so that light is incident on the reflecting mirror. Generally, a short arc type metal halide lamp for a headlamp is disposed in a headlamp body. However, it is also possible to dispose a short arc type metal halide lamp for headlamps outside the headlamp main body so that only the emitted light enters the reflecting mirror via a light guide means such as an optical fiber. If it does in this way, although a pair of headlamps will generally be arrange | positioned on the right and left of the front surface of a moving body, the short arc type metal halide lamp for headlamps can be shared with respect to each headlamp. Even if the headlamp is provided with a low beam lamp and a high beam lamp adjacent to each other, if the light distributed to each lamp is controlled using the light distributor, the headlamp short An arc-shaped metal halide lamp can be shared with each lamp.
[0105]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0106]
FIG. 2 is a central cross-sectional front view showing the arc tube in the first embodiment of the short arc type metal halide lamp for headlamps of the present invention.
[0107]
In the figure, IB is an arc tube, which includes an airtight container 1, a pair of electrodes 2, 2, a sealing metal foil 3, and an external lead wire 4.
[0108]
The hermetic container 1 includes an enclosing portion 1a and a pair of sealing portions 1b and 1b. The surrounding part 1a is formed by molding quartz glass into a spheroidal shape. The sealing part 1b and the surrounding part 1a extend in the axial direction from both axial ends.
[0109]
Each of the pair of electrodes 2 and 2 has a base portion of the electrode shaft 2 a embedded in the sealing portion 1 b and a tip located in the surrounding portion 1 b of the airtight container 1.
[0110]
The sealing metal foil 3 is made of molybdenum foil, and is hermetically sealed in the sealing portion 1b, and the external lead wire 4 is welded to the other end.
[0111]
A first halide, a second halide, and xenon are sealed in the enclosure 1b of the hermetic container 1 as a discharge medium.
[Example 1]
Airtight container 1: Enclosure inner diameter 4mm, inner volume 0.05cc
Distance between electrodes: 4.2 mm
Discharge medium: the first halide is scandium iodide ScI₃0.14 mg, sodium iodide NaI 0.86 mg, the second halide is 1 mg of the halide shown in Table 2, and xenon is 1 atm
About the short arc type metal halide lamp for headlamps of Example 1, the lamp was lit at a constant input power of 35 W, and the lamp voltage, luminous efficiency, average color rendering index (hereinafter referred to as “color rendering”) Ra and color temperature were: Table 2 shows the results measured together with the comparative examples shown below. The comparative example is a short arc type metal halide lamp for headlamps based on the prior art having the same specifications as the present embodiment except that 1 mg of mercury is enclosed instead of the second halide.
[0112]
[Table 2]

As is apparent from Table 2, in this example, the lamp voltage was 50 V or more, and the light emission efficiency was slightly lower than that of the comparative example, but there was a tendency that the color rendering properties improved.
[0113]
From the above, it can be evaluated that the present example has substantially the same characteristics as the comparative example.
[0114]
Next, Table 3 shows the results of measuring the color rendering properties and the color temperature when the lamp 3 and the lamp 1 (comparative example) in Table 2 are lit at input powers of 15 W, 20 W, 25 W and 30 W. .
[0115]
[Table 3]

As shown in Table 3, when the input was changed from 35 W (see the description related to Table 2) to 15 W in the comparative example of the lamp 1, the color temperature changed by 1520 K and the color rendering performance changed by 23. In this case, the change is too large and the light cannot be actually dimmed.
[0116]
On the other hand, in this embodiment, the change in the color temperature is 320K, and the change in the color rendering property is only 8, and the light can be adjusted sufficiently.
[0117]
Next, Table 4 shows the results of evaluation on restart.
[0118]
It should be noted that a lamp 10 having the same specification as that of the lamp 3 except that xenon Xe is sealed at 100 Torr is manufactured, and the restart voltage is also measured for this.
[0119]
[Table 4]

As shown in Table 4, in this example, the restart voltage was half that of the comparative example. For reference, a particularly significant improvement was observed in the lamp 10 in which the noble gas sealing pressure was particularly lowered and the rise of the luminous flux was not important.
[0120]
FIG. 3 is a graph showing the relationship between the rise time of the luminous flux and the sealed pressure of xenon Xe in the first embodiment of the short arc type metal halide lamp for headlamps of the present invention. In the figure, the horizontal axis represents the Xe sealing pressure (atmospheric pressure), and the vertical axis represents the luminous flux rise time (seconds).
[0121]
As is apparent from the figure, when the sealing pressure is 1 atm or more, the rise time of the light beam is remarkably shortened.
[0122]
FIG. 4 is a graph showing the relationship of the lamp voltage with respect to the encapsulated amount when iron iodide FeI2 is used as the second halide in the first embodiment. In the figure, the horizontal axis is FeI.₂, The vertical axis indicates the lamp voltage (V).
[0123]
According to the figure, it can be seen that the lamp voltage exceeds 30 V is 1 mg or more per 1 cc of the internal volume of the hermetic container.
[0124]
Note that if the internal volume is 200 mg or more per 1 cc of the airtight container, the light emission efficiency is lowered because the unevaporated FeI2 absorbs light.
[0125]
FIG. 5 is a front view showing a second embodiment of the short arc type metal halide lamp for headlamps of the present invention. In the figure, the same parts as those in FIG.
[0126]
In the present embodiment, an arc tube IB similar to that shown in FIG. 2 is configured so as to be easily mounted on a moving headlamp. In the figure, OB is an outer tube, B is a base, and IT is an insulating tube.
[0127]
The outer tube OB has an ultraviolet ray cutting performance, and houses an arc tube IB having a structure similar to that shown in FIG. 2, and both ends are fixed to a pair of sealing portions 1 b of the airtight container 1. However, the inside is not airtight and communicates with the outside air. One sealing portion 1b is planted in the base B. The external lead 4 led out to the outside from the end on the distal end side of the outer tube OB is folded back in parallel with the outer tube OB and introduced into the base B, and is connected to a terminal (not shown).
[0128]
The insulating tube IT covers the external lead wire 4.
[0129]
FIG. 6 is a perspective view showing the first embodiment of the headlamp of the present invention.
[0130]
In the figure, 31 is a reflecting mirror and 32 is a front cover.
[0131]
The reflecting mirror 31 is formed into a deformed paraboloid by molding plastics, and is configured to attach and detach a metal halide discharge lamp (not shown) shown in FIG. 5 from the back of the top.
[0132]
The front cover 32 is integrally formed with a prism or a lens by molding transparent plastics, and is airtightly attached to the front opening of the reflecting mirror 31.
[Example 2]
In this example, the following discharge medium was used in the structure and size of the short arc type metal halide lamp for headlamps shown in FIG.
Discharge medium: first halide is scandium iodide ScI₃0.14 mg, sodium iodide NaI 0.7 mg, second halide 0.4 mg halide shown in Table 5, xenon 5 atm
In addition, a comparative example in which 1 mg of mercury was further sealed was manufactured.
[0133]
Table 5 shows the results of measuring the lamp voltage, the luminous efficiency, the color rendering property (average salt color evaluation number) Ra, and the color temperature of the present example and the comparative example with the lamp input 35W constant.
[0134]
[Table 5]

The lamp voltage of the comparative example is determined by the amount of mercury enclosed, but is determined by the evaporation amount of the second halide in this embodiment. Therefore, the required lamp voltage can be easily obtained by keeping the arc tube warm. As can be understood from Table 5, in this embodiment, the lamp voltage is lower than that of the comparative example, but it is 50 V or more, and this type of short arc type metal halide lamp for a headlamp has an electronic lighting circuit. Since it is used and lit, there is no practical problem. In terms of characteristics, the luminous efficiency is a little inferior, but there is a slight emission of added metal (such as aluminum Al) in the visible range, so the color rendering tends to improve.
[0135]
FIG. 7 is a chromaticity diagram showing changes in chromaticity of the lamp 2 in Table 5 and the lamp 1 as a comparative example in Example 2 of the present invention.
[0136]
This chromaticity diagram shows the chromaticity range of white described in the explanation of automotive lamps in Japanese Industrial Standard JIS D 5500-1984. A curve C in the figure shows a change in chromaticity of the present embodiment. Curve D shows the change in chromaticity of the comparative example. The number given near the measurement point of each curve shows the elapsed time (seconds) after the start of lighting. In these measurements, each lamp is turned on using an electronic lighting circuit set so that a 2.6 A lamp current flows immediately after the power is input and the current is gradually reduced to a constant lamp power control of 35 W. I went.
[0137]
As is apparent from the figure, in this example, the light emission entered the white range within 0.5 seconds after lighting, whereas in the comparative example, the light entered the white range after 18 seconds.
[0138]
Next, Table 6 shows the results of measuring the average color rendering index Ra and the color temperature (K) when the lamps 2 and 1 in Table 5 are turned on with the lamp inputs 15 W, 20 W, 25 W and 30 W.
[0139]
[Table 6]

Since the lamp 1 (comparative example) has a high vapor pressure of mercury, all the mercury is evaporated even if the lamp input is reduced to 15 W. For this reason, as the lamp input decreases, the emission of mercury becomes dominant and the color temperature rises.On the other hand, the color rendering property decreases, so the comparative example is suitable for dimming in a practical sense. You will understand that
[0140]
On the other hand, it can be understood that the lamp 2 (the present embodiment) has a small change in both the color rendering properties and the color temperature and is sufficiently suitable for light control.
[0141]
Furthermore, Table 7 shows the result of measuring the restart voltage at the time of the instant restart (hot restart) of this example. The measurement was performed by measuring the restart voltage when the lamp was turned on and off for 30 minutes and restarted after 10 seconds. In addition, when the light extinction time becomes long, the electrode temperature decreases and it becomes difficult to start. On the other hand, the vapor pressure of mercury or metal halide in the arc tube decreases as the turn-off time becomes longer, and it becomes easier to start. As a result of these conflicting tendencies, restarting is most difficult to start when the turn-off time is about 10 seconds.
[0142]
[Table 7]

The lamp 1 (comparative example) has a high starting voltage because the mercury vapor pressure is still high.
[0143]
On the other hand, in the lamps 2 to 6 (in this embodiment), the metal vapor pressure of the second metal halide is clearly lower than that of mercury during steady lighting. Still, 10 seconds after extinction is when the vapor pressure difference between the metal vapor pressure of metal halide and mercury is the smallest. This indicates that the present embodiment has remarkably good restart characteristics compared to the conventional example in which mercury is enclosed.
[0144]
Next, Table 8 shows the results of measuring the color characteristics in the vicinity of the electrodes when the lamp of this example is lit by direct current. This is obtained by projecting the lamp on a screen when the lamp is turned on with a lamp input of 35 W and measuring the color temperature (K) between the vicinity of the anode and the vicinity of the cathode.
[0145]
[Table 8]

The lamp 1 (comparative example) has a large difference in color temperature between the anode side and the cathode side. It is impossible to cover such a color temperature difference with the design of the headlamp.
[0146]
On the other hand, the lamps 2 to 6 (the present embodiment) are sufficiently suitable for practical use because the color temperature difference is small.
[Example 3]
In this embodiment, in the short arc metal halide lamp for headlamps shown in FIG. 5, both ends of the outer tube 21 are hermetically sealed to the sealing portions 1b and 1b of the arc tube 1, respectively, and the inside is evacuated. It has. Other configurations are the same as those of the second embodiment.
[0147]
Table 9 shows the results of measuring the lamp voltage (V), the luminous efficiency (lm / W), the color rendering property (average color rendering index) Ra, and the color temperature (K) for this example and the comparative example. . The comparative example is the same as the present example except that 1 mg of mercury is enclosed instead of the second halide.
[0148]
[Table 9]

In this embodiment, the vacuum in the outer tube increases the lamp voltage and dramatically improves the light emission efficiency. In contrast, the comparative example was only slightly improved.
[Example 4]
In this example, the discharge medium was enclosed as follows in the same structure and size as the short arc type metal halide lamp for headlamps shown in FIG.
Discharge medium: first halide is scandium iodide ScI₃0.14 mg and sodium iodide NaI 0.7 mg, the second halide is zinc iodide ZnI₂0.4 mg and 0.1 mg of added halide shown in Table 10, xenon is 5 atm
Table 10 shows the results of measuring the lamp voltage (V), luminous efficiency (lm / W), color rendering (average color rendering index) Ra, and color temperature (K) for this example.
.
[Table 10]

The second halide generally has a lower vapor pressure than mercury, but at the same pressure, it contributes more to the lamp voltage formation than mercury.
[0149]
However, since mercury has a constantly high vapor pressure, the small arc short metal halide lamp for small headlamps with a small load such as rated lamp power for moving headlamps of 100 W or less is completely mercury. Evaporates. For this reason, the lamp voltage can be adjusted by the amount of mercury enclosed.
[0150]
On the other hand, in the case of the present invention in which the second halide is enclosed instead of mercury, since the vapor pressure is saturated at the stage of incomplete evaporation of the enclosed halide, the lamp voltage further increases. do not do.
[0151]
However, the lamp voltage can be further increased by enclosing a plurality of types of second halides as in this embodiment. That is, when one of the second halides is saturated, evaporation of the added second halide contributes to an increase in lamp voltage. Therefore, the lamp voltage can be increased when a plurality of types of the second halides are mixed than when they are one type.
[Example 5]
In this example, the discharge medium was enclosed as follows in the same structure and size as shown in FIG.
Discharge medium: first halide is scandium iodide ScI₃0.14 mg and sodium iodide NaI 0.7 mg, second halide 0.4 mg halide shown in Table 11, third halide: cesium iodide CsI 0.1 mg, xenon 5 atm
Further, as a comparative example, a product having the same specifications as in the present embodiment was manufactured except that 1 mg of mercury was enclosed instead of the second halide.
[0152]
Then, with respect to the present example and the comparative example, the lamp input is lit at a constant 35 W, the lamp voltage (V), the luminous efficiency (lm / W), the color rendering property (average color rendering index) Ra, and the color temperature (K). The results of measuring are shown in Table 11.
[0153]
[Table 11]

In this example, the addition of cesium iodide CsI as the third halide hardly changed the color rendering property Ra and the color temperature, but the arc temperature distribution was flattened, so that the heat loss was reduced. As a result, luminous efficiency is improved. However, in the comparative example in which mercury is enclosed, the efficiency is not improved even when the third halide is added.
[0154]
Moreover, since there is no light emission of mercury having a low light emission efficiency, the light emission efficiency is higher than that of the comparative example.
[0155]
Next, Table 12 shows the luminous efficiency (lm / W) when the amount of the third halide cesium iodide CsI enclosed in the lamp 3 is changed.
[0156]
[Table 12]

From Table 12, the addition of CsI is effective from 0.01 mg. On the other hand, if the amount added is too large, the vapor pressure of the luminescent metal is lowered, resulting in a reduction in efficiency.
[0157]
Furthermore, Table 13 shows the results of measuring the restart voltage at the time of instantaneous restart (hot restart) under the same conditions as in Example 2 for this example.
[0158]
[Table 13]

In this example, the restart voltage is much lower than that of the comparative example in which mercury is encapsulated, but the restart voltage is slightly higher than in the case of not enclosing the third halide cesium iodide CsI. Tend. However, there is no problem at all practically.
[0159]
FIG. 8 is a front view showing an arc tube according to a third embodiment of the short arc type metal halide lamp for headlamps of the present invention. In the figure, the same parts as those in FIG.
[0160]
This embodiment is different in that it is configured to be lit by direct current. In the figure, 2_KIs the cathode, 2_AIs the anode. Cathode 2_KIs relatively thin, anode 2_AIs relatively thick.
[0161]
In order to manufacture the arc tube IB of the short arc type metal halide lamp for headlamps having the above structure, first, a tube in which sealing tubes for forming the sealing portions 1a are joined to both ends of the hermetic container 1 is prepared.
[0162]
Next, cathode 2_KAfter inserting the connection assembly of the molybdenum foil 3 and the external lead wire 4 into one sealing tube, the sealing tube is heated and melted using an oxyhydrogen burner, and sealed with a pinch seal to form the cathode 2_KIs sealed in the airtight container 1.
[0163]
Thereafter, the first and second halides are sealed in the hermetic vessel 1 from the other sealing tube in a nitrogen gas atmosphere, and the anode 2_AThen, the connection assembly of the molybdenum foil 3 and the external lead wire 4 is inserted into the sealing tube, and a predetermined inter-electrode distance is set to 4.2 mm.
[0164]
Further, these assemblies are attached to an exhaust system through a sealing tube to evacuate the inside of the hermetic container 1, and after introducing xenon at 2 atm, the other sealing tube is mounted while cooling the hermetic container 1. Heat and melt with an oxyhydrogen burner, then pinch seal to anode 2_AIs sealed in an airtight container 1 to complete a metal halide discharge lamp. Hereinafter, Example 6 in the present embodiment will be described.
[Example 6]
Airtight container: the surrounding portion is 4 mm in inner diameter and 7 mm in length, and the sealing portion is 30 mm in length. Electrode: Cathode 2_KIs a thorium-containing tungsten rod 0.4 mm in diameter and 6 mm in length, anode 2_AIs a tungsten rod with a diameter of 0.8mm and a length of 6mm
Sealing metal foil: molybdenum foil having a width of 1.5 mm, a length of 15 mm and a thickness of 15 μm
External lead wire: conductor 0.5mm in diameter and 25mm in length
Discharge medium: first halide is scandium iodide ScI₃0.17 mg, sodium iodide NaI 0.83 mg, second halide is lamp 2 is ZnI₂0.4 mg, lamp 3 is AlI₃0.2 mg, lamp 4 is FeI₂0.4mg
As a comparative example (lamp 1), a product having the same specifications as in this example was manufactured except that 1 mg of mercury was enclosed instead of the second halide.
[0165]
Thus, with respect to the lamp 2 (this example) and the lamp 1 (comparative example), the luminous efficiency (lm / W) and color rendering properties when the lamp input is lit at 20 W, 25 W, 30 W and 35 W with respect to the rated 35 W. Table 14 shows the results of measurement of (average color rendering index) Ra and color temperature (K).
[0166]
[Table 14]

FIG. 9 is a chromaticity diagram showing the rise of the chromaticity characteristics of the lamp 2 in Example 6 in comparison with the comparative example. In the figure, a curve E shows the rising of the luminous flux of the present embodiment. Curve F shows the rise of the luminous flux of the comparative example.
[0167]
This embodiment is in the white region from the beginning of lighting. The comparative example took about 1 minute to enter the white region.
[0168]
Next, each lamp was lit for 60 minutes at 42 W, which is a 20% increase in the rated lamp power, and was subjected to a blinking test for 15 seconds to investigate whether or not the hermetic container had ruptured. There was nothing.
[0169]
Further, Table 15 shows the results of the measurement of the restart voltage necessary for the instantaneous restart after 2 seconds from turning off.
[0170]
[Table 15]

FIG. 10 is a graph showing the relationship with the luminous flux rise time when the noble gas sealing pressure is changed in the third embodiment of the short arc metal halide lamp for headlamps of the present invention shown in FIG. . In the figure, the horizontal axis represents the xenon sealing pressure (atmospheric pressure), and the vertical axis represents the luminous flux rise time (seconds).
[0171]
From the figure, it was found that when the sealed pressure of xenon is 1 atm or more, the rise time of the light beam is suddenly shortened and becomes practical.
[0172]
FIG. 11 shows that, in the third embodiment, ZnI is used as the second halide.₂It is a graph which shows the relationship of the lamp voltage (V) at the time of changing the amount of sealing (mg / cc).
[0173]
From the figure ZnI₂If 1 mg / cc or more is sealed, it can be understood that the lamp voltage can be increased to 30 V or more, which is a desired value for lighting using an electronic lighting circuit.
[0174]
FIG. 12 is a circuit diagram showing a first embodiment of the metal halide lamp lighting device of the present invention.
[0175]
  This embodiment is a metal halide.lampIs configured to be lit in direct current.
[0176]
  In the figure, 71 is a DC power source, 72 is a chopper, 73 is a control means, 74 is a lamp current detection means, 75 is a lamp voltage detection means, 76 is a start means, and 77 is a metal halide.lampIt is.
[0177]
The DC power supply 71 is a battery or a rectified DC power supply. In the case of a mobile object, a battery is generally used. However, it may be a rectified DC power source that rectifies AC. If necessary, smoothing is performed by connecting electrolytic capacitors 71a in parallel.
[0178]
  The chopper 72 converts a DC voltage into a voltage of a required value, and a metal halide.lamp77 is controlled as necessary. When the DC power supply voltage is low, a step-up chopper is used, and when it is high, a step-down chopper is used.
[0179]
  The control means 73 controls the chopper 72. For example, immediately after lighting, metal halidelamp77, a lamp current more than three times the rated lamp current is supplied from the chopper 72, and thereafter, the lamp current is gradually reduced with the passage of time, and is controlled so as to reach the rated lamp current.
[0180]
The lamp current detection means 74 is inserted in series with the lamp, detects the lamp current, and inputs the control input to the control means 73.
[0181]
The lamp voltage detection means 75 is connected in parallel with the lamp, detects the lamp voltage, and inputs the control voltage to the control means 73.
[0182]
  The control means 73 generates a constant power control signal by feedback input of the detection signal of the lamp current and the lamp voltage, and controls the chopper 72 at a constant power. Further, the control means 73 has a built-in microcomputer in which a temporal control pattern is incorporated in advance, and immediately after lighting, a lamp current more than three times the rated lamp current is metal halide.lampThe chopper 72 is controlled so as to reduce the lamp current as time passes.
[0183]
  The starter 76 applies a 20 kV pulse voltage at the start to the metal halide.Lamp 77 is configured so that it can be supplied to the power source 7.
[0184]
Thus, according to the present embodiment, a required light flux is generated immediately after lighting while DC lighting. As a result, it is possible to realize lighting with a luminous flux of 25% and a luminous flux of 80% after 1 second after turning on the power necessary as a headlamp for a moving body such as an automobile.
[0185]
In the case of this embodiment, since a DC-AC conversion circuit is not required, the cost can be reduced by about 30% compared to AC lighting. Further, the weight can be reduced by 15%. Along with this, the lighting circuit becomes inexpensive.
[0186]
FIG. 13 is a circuit diagram showing a second embodiment of the metal halide lamp lighting device of the present invention. In the figure, the same parts as those in FIG.
[0187]
  This embodiment is a metal halide.lampIs different in that it is configured to light up alternating current.
[0188]
Reference numeral 78 denotes AC conversion means. The AC conversion means 78 is composed of a full bridge inverter. That is, a pair of switching means 78a, 78a in series is connected in parallel between the output ends of the chopper 72 to form a bridge circuit, and the oscillation output of the oscillator 78b is switched in the diagonal direction of the four switching means 78a. By alternately supplying to the means, high-frequency alternating current is generated between the output ends of the bridge circuit.
[0189]
  And metal halide by high frequency alternating currentlamp77 is turned on.
[0190]
Also in this AC lighting type configuration, the same control as in FIG. 12 is performed.
[0191]
FIG. 14 is a conceptual diagram showing a second embodiment of the headlamp of the present invention.
[0192]
FIG. 15 is a conceptual diagram showing a portion of the optical distributor.
[0193]
In the figure, 81 is a lighting circuit, 82 is a light distributor, 83 is a main optical fiber, 84 is an optical shutter 85, an individual optical fiber, and 86 is a lamp.
[0194]
As the lighting circuit 81, the lighting circuit shown in FIG. 12 or 13 can be used.
[0195]
  The light distributor 82 includes a case 82a, a light reflecting / reflecting surface 82b, and a metal halide.lamp82c and an optical connector 82d. And metal halidelampThe light generated from 82c is distributed to the main optical fiber 83 from the portion of the optical connector 82d.
[0196]
The main optical fiber 83 transmits the light distributed from the light distributor 82 to the optical shutter 84.
[0197]
The optical shutter 84 selectively transmits to each lamp 86 via the individual fiber 85.
[0198]
The lamp unit 86 includes a high beam lamp unit 86a, a low beam lamp unit 86b, and a fog lamp unit 86c, and two sets are disposed on both sides of the front part of a moving body such as an automobile.
[Example 7]
This example is a short arc type metal halide lamp for headlamps suitable for use in the second embodiment of the headlamp shown in FIG.
Rated lamp power: 80W
Distance between electrodes: 2mm
Other structure: similar to that shown in FIG.
Discharge medium: first halide is scandium iodide ScI₃0.3 mg, sodium iodide NaI 1.5 mg, the second halide is lamp 2 is ZnI₂1mg, AlI₃1 mg, MnI₂1 mg, lamp 3 is ZnI₂2 mg, GaI₃1mg, CrI₂1 mg, both xenon and 5 atm
Further, as a comparative example (lamp 1), a product having the same specifications as in this example was manufactured except that 15 mg of mercury was enclosed instead of the second halide.
[0199]
Then, the present example and the comparative example were turned on at a constant rating of 80 W, and the lamp voltage (V), luminous efficiency (lm / W), color rendering (average color rendering index) Ra, and color temperature (K) were measured. The results are shown in Table 15.
[0200]
[Table 15]

As can be understood from Table 15, in this example, characteristics almost equivalent to those of the comparative example in which mercury is sealed can be obtained. Further, in the headlamp shown in FIG. 14, the necessity of changing the light by changing the input increases, and it is extremely useful that the light can be adjusted at that point.
[0201]
【The invention's effect】
    According to the first aspect of the present invention, an airtight container including a fire-resistant and light-transmitting hermetic container, a pair of electrodes having a distance between electrodes of 6 mm or less, a first halide, a second halide, and a rare gas. The first halide is made of a halide containing sodium Na and scandium Sc, the second halide has a relatively high vapor pressure, and the first halide and the second halide are sealed in the container. In the presence of halides, the energy concentrates on the light emission of the metal of the first halide and is less likely to emit light in the visible region than the metal of the first halide. Magnesium Mg, iron Fe, cobalt Co, chromium Cr, zinc Zn, nickel Ni, manganese Mn, aluminum Al, antimony Sb, rhenium Re and gallium G as metals One or more kinds in an airtight container volume 1cc per selected metal from the group consisting ofOver 1.5mgMade of halidesThe rare gas is xenon enclosed at 1 atm or higherA discharge medium, which is essentially sealed with mercury and configured to be lit in either alternating current or direct current,The lamp voltage increases to almost the same level as this kind of metal halide lamp with mercury enclosed,A short arc type metal halide lamp for a headlamp that exhibits the effects listed below can be provided.
[0202]
  1Good beam rise characteristics at start-up. In the present invention, since xenon is enclosed as a rare gas at a pressure of 1 atm or higher, in addition to the above-described chromaticity rising characteristics, scandium Sc and sodium, which are luminescent metals of the first metal halide from the start, are used. Na emits light to improve the luminous flux rising characteristics at the start. Further, by supplying a lamp current more than three times the rated lamp current immediately after lighting and lighting so as to reduce the current as time elapses, a luminous flux of 25% with respect to the rating is obtained 4 seconds after the power is turned on. It is possible to realize lighting with 80% luminous flux after 2 seconds. On the other hand, in a conventional metal halide lamp for a headlamp that encloses a luminescent metal halide and mercury, a high current encapsulated xenon and a large current flow immediately after lighting, gradually reducing the current, Xenon emits light, then mercury emits, and this mercury emission lasts until 10 to 20 seconds, thereby solving the problem of the rising characteristics of light flux.
[0203]
  2 Good rise in chromaticity at start-up.In the present invention, since mercury is not essentially enclosed, it is not mercury as in the prior art that substantially contributes to light emission at the time of rising of the light beam immediately after starting, but substantially constitutes the first halide. Since it is light emission of scandium Sc and sodium Na which are light emitting metals, the chromaticity rise at the time of starting becomes favorable. On the other hand, in the conventional metal halide lamp for headlamps in which mercury is enclosed, as described above in the section of the problem to be solved by the invention, light emission at start-up is mainly light emission from mercury, so that there is a problem of rising of luminous flux. Is solved, but there is a problem because the rise of chromaticity is bad.
[0204]
  3White light emission can be obtained with high luminous efficiency. In the present invention, in addition to essentially not containing mercury, scandium Sc and sodium Na halides, which are luminescent metals having a luminous efficiency higher than mercury, are added. 1 When used as a halide, the white light emission necessary for a headlamp can be obtained and the luminous efficiency is increased.
[0205]
  4In an optical system using a reflecting mirror, high light collection efficiency can be obtained.
[0206]
  5Instant restart is easy.
[0207]
  6Dimming is possible.
[0208]
  7Less bursting during lighting of the airtight container.
[0209]
  8There is little variation in emission color with respect to variations in shape and dimensions.
[0210]
9 Suitable for direct current lighting.
[0211]
    According to the invention of claim 2, the discharge medium is made of a rare gas.5Because xenon is sealed above atmospheric pressure, chromaticity rise characteristics and luminous flux rise characteristics at startupOne layerIt is possible to provide a short arc metal halide lamp for a good headlamp.
[0212]
According to the invention of claim 3, the short arc type metal halide lamp for headlamps according to claim 1 or 2 and an electronic lighting device for energizing the short arc type metal halide lamp for headlamps are provided. Thus, a metal halide lamp lighting device having the effects of claim 1 or 2 can be provided.
[0213]
According to invention of Claim 4, the headlamp main body provided with the reflecting mirror, and the short lamp for headlamps of Claim 1 or 2 arrange | positioned so that light emission may inject into the reflecting mirror of a headlamp main body. By providing the arc type metal halide lamp and the electronic lighting device for energizing the short arc type metal halide lamp for the headlamp, the headlamp having the effect of claim 1 or 2 can be provided. .
[Brief description of the drawings]
FIG. 1 is a graph showing arc temperatures in an example in which a second halide is enclosed instead of mercury and an example in which mercury is enclosed in a short arc type metal halide lamp.
FIG. 2 is a central sectional front view showing a first embodiment of a short arc type metal halide lamp for a headlamp according to the present invention.
FIG. 3 is a graph showing the relationship between the rise time of light flux and the sealed pressure of xenon Xe in the first embodiment of the short arc metal halide lamp for headlamps of the present invention.
FIG. 4 is a graph showing the relationship of the lamp voltage with respect to the encapsulated amount when iron iodide FeI2 is used as the second halide in the first embodiment.
FIG. 5 is a front view showing a second embodiment of a short arc type metal halide lamp for a headlamp according to the present invention.
FIG. 6 is a perspective view showing the first embodiment of the headlamp of the present invention.
FIG. 7 is a chromaticity diagram showing a change in chromaticity of the lamp 2 in Table 5 and the comparative lamp 1 in Example 2 of the present invention
FIG. 8 is a front view showing a third embodiment of a short arc type metal halide lamp for a headlamp according to the present invention.
FIG. 9 is a chromaticity diagram showing the rise of chromaticity characteristics of the lamp 2 in Example 6 in comparison with a comparative example.
FIG. 10 is a graph showing a relationship with a luminous flux rise time when the rare gas filling pressure is changed in the third embodiment of the short arc metal halide lamp for headlamps of the present invention shown in FIG. 8;
FIG. 11 also shows ZnI as the second halide in the third embodiment.₂Is a graph showing the relationship of lamp voltage (V) when the enclosed amount (mg / cc) is changed
FIG. 12 is a circuit diagram showing a first embodiment of a metal halide lamp lighting device of the present invention.
FIG. 13 is a circuit diagram showing a second embodiment of the metal halide lamp lighting device of the present invention.
FIG. 14 is a conceptual diagram showing a second embodiment of the headlamp of the present invention.
FIG. 15 is a conceptual diagram showing a portion of the same optical distributor.
FIG. 16 is a conceptual diagram for explaining a lamp voltage in a metal halide lamp.
FIG. 17 is a graph showing the emission spectrum distribution of a conventional short arc metal halide lamp for light projection.
[Explanation of symbols]
1 ... Airtight container
1a ... Surrounding part
1b ... Sealing part
2 ... Electrode
2a ... Electrode shaft
3 ... Sealed metal foil
4 ... External lead wire
IB ... arc tube
IT ... Insulating tube
OB ... Outer pipe

Claims (4)

Fireproof and translucent airtight container;
A pair of electrodes sealed in an airtight container and having an interelectrode distance of 6 mm or less;
A first halide, a second halide, and a rare gas are enclosed in an airtight container. The first halide is a halide containing sodium Na and scandium Sc, and the second halide is vapor pressure. Is relatively large, and in the state where the first halide and the second halide coexist, the energy concentrates on the light emission of the metal of the first halide and becomes the metal of the first halide. In comparison, it is difficult to emit light in the visible range, and as a metal having a small amount of light emission in the visible range, magnesium Mg, iron Fe, cobalt Co, chromium Cr, zinc Zn, nickel Ni, manganese Mn, aluminum Al, antimony Sb, rhenium Re and selected one or more in an airtight container volume 1cc per 1.5mg from the group consisting of gallium Ga Of Ri Do halides, rare gas and a discharge medium Ru xenon der which is sealed above 1 atmosphere pressure;
A short arc type metal halide lamp for a headlamp, characterized in that it is essentially sealed with mercury and is lit with either alternating current or direct current. The short arc type metal halide lamp for a headlamp according to claim 1, wherein the discharge medium is xenon in which a rare gas is sealed at 5 atm or more. A short arc type metal halide lamp for a headlamp according to claim 1 or 2;
An electronic lighting device for energizing a short arc metal halide lamp for a headlamp;
A metal halide lamp lighting device comprising: A headlamp body with a reflector;
The short arc type metal halide lamp for a headlamp according to claim 1 or 2, wherein the headlamp main body is disposed so that light is incident on a reflector of the headlamp body;
An electronic lighting device for energizing a short arc metal halide lamp for a headlamp;
A headlamp characterized by comprising:

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