JP2004227820A

JP2004227820A - Discharge lamp

Info

Publication number: JP2004227820A
Application number: JP2003011716A
Authority: JP
Inventors: Takenobu Iida; 武伸飯田; Hidemi Orito; 日出海折戸; Minoru Matsumoto; 稔松本; Yosuke Suzuki; 陽介鈴木; Akihisa Kaneko; 晃久金子; Koichi Matsuo; 浩一松尾
Original assignee: Iwasaki Electric Co Ltd
Current assignee: Iwasaki Electric Co Ltd
Priority date: 2003-01-21
Filing date: 2003-01-21
Publication date: 2004-08-12

Abstract

【課題】内部に放電ガスが封入されたガラス容器の外側に電極を配設し、この電極に高周波電圧を印加して高い放射照度を得る電解結合型高周波放電ランプ（いわゆるエキシマランプ）において、始動電圧を低くするとともにその始動を安定化する。また、この放電ランプを組み込んだ照射器内の絶縁性を高め安全性を確保する。
【解決手段】前記放電ランプにおいて、放電ガスを封入したガラス容器の一部または全周にへこみ若しくはくびれを配設して放電空間距離の短い部分を設け、このへこみ若しくはくびれの外面、及びこれと対向する位置の前記ガラス容器外面とにそれぞれ配設した一対の電極を具備する構成とする。
【選択図】図１An electrode is provided outside a glass container in which a discharge gas is sealed, and a high frequency voltage is applied to the electrode to obtain a high irradiance, thereby starting an electrolytically coupled high frequency discharge lamp (so-called excimer lamp). Reduce the voltage and stabilize its starting. In addition, the insulation in the irradiator incorporating the discharge lamp is enhanced to ensure safety.
In the discharge lamp, a dent or a constriction is provided on a part or the entire circumference of a glass container filled with a discharge gas to provide a portion having a short discharge space distance, and the outer surface of the dent or the constriction, and It is configured to include a pair of electrodes respectively disposed on the outer surface of the glass container at a position facing each other.
[Selection diagram] Fig. 1

Description

【０００１】
【発明の属する技術分野】
本発明は特に、内部に放電ガスが封入されたガラス容器の外側に電極を配設し、この電極に高周波電圧を印加する電界結合型放電ランプ、即ちＥ放電ランプ（いわゆるエキシマランプ）の始動電圧を下げるための改良に関する。
【０００２】
【従来の技術】
一般にこのような放電はネオン、アルゴン、キセノン、クリプトン等の希ガスを封入したガラス容器で一般には合成石英管に電界結合型無電極放電を構成し、一般に参考文献１及び２に開示されている無電極放電を作用させてエキシマ光を放射させるエキシマランプの構成に利用されている。特にキセノンガスを封入したエキシマランプは中心波長１７２ｎｍ、半値幅１４ｎｍの放射スペクトル分布を持つ。この紫外光は特に真空紫外光と呼ばれ、波長がさらに短いためエネルギーが一般の低圧水銀ランプが放射する波長の１８５ｎｍや２５４ｎｍの紫外光に比べて格段に大きいエネルギーを持つ。そこで、活性酸素やオゾンの発生が多く、特に近年液晶素子やＰＤＰ素子のガラス洗浄に多く利用され、また半導体基板のシリコンウエハーの表面加工に利用されてきた。
【０００３】
【参考文献１】
「無電極放電ランプの技術動向／電界結合放電Ｅ放電の解説」照明学会誌、第７７巻第５号、２１ページ（１９９３年）
【０００４】
【参考文献２】
ＯｐｌｕｓＥ，Ｖｏｌ．２２，Ｎｏ．８，１０２２〜１０２４ページ（２０００年）
【０００５】
図７及び図８に従来の一般的なエキシマランプを示す。このランプは、合成石英からなる中空を持つ円筒状の灯体１と中空を貫通するガラス製水冷管２からなり、その灯体１の外面に放射光を出来る限り遮らない程度の金属ネット状の外側主電極３を、ガラス製水冷管２の表面上の灯体１の端面に近い側の表面に長さの短い電極、即ち始動電極５及び口出９を、灯体１の中空内面の中央全体を軸方向に覆ってなる、長さの長い内側主電極４を配設して構成されている。
【０００６】
前述のように用途拡大と洗浄効率が求められるに従って、このようなエキシマ光の高出力化が求められるようになり、キセノンエキシマランプを利用した照射器の照度は、放射窓面において８ｍＷ／ｃｍ^２から４０ｍＷ／ｃｍ^２以上（ＮＩＳＴ標準による照度計による計測）の照度が求められるようになってきた。
【０００７】
そこで、このような高照度を達成する方法としては従来より、エキシマ光が発光するエネルギー範囲、即ち可視光発光が増えない範囲で高周波入力電力を増やす事、あるいは図７に示すような中空円筒構造の灯体１の外管１ａの寸法と内管１ｂの寸法の適正化、更には封入される希ガスの圧力（この場合はキセノンガス圧）の適正化が実施されている。
【０００８】
即ち、図７のランプにおいて放電空間距離ｄ１が１１ｍｍ、全長２８０ｍｍ、外面ネット主電極長２４０ｍｍでキセノンガス圧を変化させ、図８に示す照射器にこのランプを装着し、その内部を窒素ガスで充分に置換する。図９に示す回路構成においてランプへの高周波入力電力１０ａを高周波電源１０の電力増幅への入力で規定し１７０Ｗで一定にしてキセノンガス圧を変化させた時の照射器窓面６の照度を図１０に示す。ここでガス圧を５３，３００Ｐａ（４００ｔｏｒｒ）から６６，７００Ｐａ（５００ｔｏｒｒ）にすると照度が急激に高くなる。即ち、１７２ｎｍのエキシマ光の放射強度が高くなる。
【０００９】
次に、図７に示すランプ構造でキセノンガス圧を５３，３００Ｐａで一定にして外管１ａの内径を固定して内管１ｂの外径を変化させ、高周波入力電力１７０Ｗで図８に示す照射器の窓面６の照度を図１１に示す。このように、放電空間距離ｄ１を長くする事によって照度が高くなる。
【００１０】
【発明が解決しようとする課題】
ここでキセノンガス圧を高め、例えば５３，３００Ｐａにして放電空間を広げると、ここに示す電界結合型無電極放電を開始させるための始動電圧が高くなる欠点がある。図７に示す構造のランプのように外部始動電極を用いた場合の放電破壊電圧に対しては、一般に開示されている参考文献３に記載のパッシェンの法則が成立し、放電破壊電圧はガス圧と放電距離の積と反比例の関係にある。
【００１１】
【参考文献３】
「東北大学基礎電子工学入門講座気体放電」（近代科学社）１５７ページ（１９８９年）
【００１２】
ここで、図７に示す構造のランプで図８に示す照射器窓面６の照度を４０ｍＷ／ｃｍ^２以上得るためにキセノンガス圧を５３，３００Ｐａとし、外管１ａの内面と内管１ｂの外面との距離、即ち放電空間距離ｄ１を１１ｍｍに設定し、図９に示すような始動器１１を含む回路構成により放電を行なう場合、放電破壊電圧は２５ｋＶ以上のパルス電圧を必要とする。このような高電圧を図７に示すようなエキシマランプを始動させるために印加させる事は、始動電極面５及び口出９からのコロナ放電や縁面放電を誘発し、始動を不安定にさせるし、また照射器内の安全性、即ち絶縁性が確保できないという問題を生じる。
【００１３】
本発明はかかる点に鑑みてなされたものであって、電界結合型高周波エキシマランプにおいてこのような高い始動電圧を必要とする事によりもたらされる問題を解決するとともに、低始動電圧化を図ることにより始動電極面からのコロナ放電や縁面放電の誘発をなくして照射器内の安全性、即ち絶縁性を確保し、かつ始動性を安定させたエキシマランプを提供する事を目的とする。
【００１４】
【課題を解決するための手段】
本発明は上記課題を解決するために次の構成を有する。即ち、請求項１記載の放電ランプは、放電ガスを封入したガラス容器と、前記ガラス容器の一部または全周に配設したへこみ若しくはくびれと、前記へこみ若しくはくびれの外面に接触させて配設した電極と、前記電極に対向する位置の前記ガラス容器外面に接触させて配設した電極とを具備する事を特徴とする。
【００１５】
請求項２記載の放電ランプは、請求項１記載の放電ランプにおいて前記ガラス容器の外面の互いに対向する位置に一対の高周波電力供給用電極を配設した事を特徴とする。
【００１６】
請求項３記載の放電ランプは、請求項１または請求項２記載の放電ランプにおいて前記へこみ若しくはくびれの外面に接触させて配設した電極と、前記電極に対向する位置の前記ガラス容器外面に接触させて配設した電極との間に高電圧パルスを印加する事を特徴とする。
【００１７】
請求項４記載の放電ランプは、請求項１ないし請求項３記載の放電ランプにおいて前記へこみ若しくはくびれの外面に接触させて配設した電極と前記ガラス容器の外面に接触させて配設した前記高周波電力供給用電極の一方とを結線した事を特徴とする。
【００１８】
請求項５記載の放電ランプは、請求項１記載の放電ランプにおいて前記ガラス容器内に封入する放電ガスが、キセノン、ネオン、ヘリウム、アルゴン、クリプトンから選ばれる１種のガスもしくは複数種の混合ガスである事を特徴とする。
【００１９】
請求項６記載の放電ランプは、請求項１または請求項５記載の放電ランプにおいて前記ガラス容器内に封入する物質が、前記放電ガスと、塩素、臭素、フッ素、沃素から選ばれる１種もしくは複数種である事を特徴とする。前記ガラス容器内に金属ハロゲン化物を添加した事を特徴とする。
【００２０】
請求項７記載の放電ランプは、請求項１または請求項５記載の放電ランプにおいて前記ガラス容器内に金属ハロゲン化物を添加した事を特徴とする。
【００２１】
請求項８記載の放電ランプは、請求項１ないし請求項７記載の放電ランプにおいて前記へこみもしくはくびれに接触させて配設した電極と対向する位置の前記ガラス容器の外面に、へこみ若しくはくびれを配設するとともに、もう一方の電極をそこに接触させて配設した事を特徴とする。
【００２２】
請求項９記載の放電ランプは、請求項１または請求項２または請求項７記載の放電ランプにおいて前記ガラス容器は石英からなる事を特徴とする。
【００２３】
請求項１０記載の放電ランプは、請求項１ないし請求項９記載の放電ランプにおいて前記ガラス容器は、一対の同軸円筒面と前記円筒の中心軸に直交する一対の平行面に囲まれた部分の領域に相当する、筒殻の厚い中空円筒に近似した立体的形状を具備し、前記高周波電力供給用電極は、前記中空円筒の外側円筒外面と内側円筒内面とにそれぞれを配設し、前記へこみ若しくはくびれは、中空円筒の外面に配設した事を特徴とする。
【００２４】
請求項１１記載の放電ランプは、請求項１ないし請求項１０記載の放電ランプにおいて前記中空円筒状ガラス容器の外側円筒外面にネット状の電極を配設した事を特徴とする。
【００２５】
【発明の実施の形態】
本発明の実施例を図面を参照して以下に説明する。図１は本発明を構成する電界結合型高周波エキシマランプの中心軸を含む概略断面図であり、図２はその外観図である。ランプを構成するガラス容器は全て合成石英からなる。外径３５ｍｍ、内径３３ｍｍ、長さ２８０ｍｍの石英管に端部近傍に予めくびれ加工を施してなる外管１ａと、外径１１ｍｍ、内径９ｍｍ、長さ２８０ｍｍの内管１ｂの両端面がそれぞれ接合されて全体として閉じた一つの放電容器、即ち灯体１が構成される。主放電空間距離ｄ１は１１ｍｍである。くびれ８の開口部は幅１０ｍｍ、くびれ８加工部の石英肉厚は１ｍｍに加工し、そのくびれ８の先端と内管１ｂで構成される最短放電空間距離ｄ２を２ｍｍとする。放電空間１３には５３，３００Ｐａ（４００ｔｏｒｒ）の圧力のキセノンガスが封入される。内管１ｂの内側の中空を貫通するガラス製水冷管２の外面には、外管１ａのくびれ８と対向する位置を含む端部近傍の外面を覆う金属箔状の、始動電極及びその口出９と、それ以外の外面のほぼ全体を覆う内側主電極４とが配設される。外管１ａの外面に放射光を遮らない程度のネット状の外側主電極３が配設される。また、ネット状の外側主電極３は外管１ａのくびれ８のへこみ部分の外面に十分に接触させるように配設される。ガラス製水冷管２の中には冷却水が流れる。図６の回路構成に示すように外側主電極３と内側主電極４の間に周波数２．４ＭＨｚ、パルスピーク電圧４ｋＶの高周波電源１０が接続される。外側主電極３と始動電極５との間に高電圧パルスを発生する始動器１２が接続される。
【００２６】
次に、始動電圧とキセノンガス圧の関係を調べるため、図１と同様の構造でキセノンガス圧が１３，３００Ｐａ（１００ｔｏｒｒ）、２６，６００Ｐａ（２００ｔｏｒｒ）、６６，５００Ｐａ（５００ｔｏｒｒ）の電界結合型高周波エキシマランプを製作し、図６に示す回路構成に従って周波数２．４ＭＨｚ、パルスピーク電圧４ｋＶの高周波電源１０とパルス幅５０μｓｅｃの始動器１２を接続し、くびれ８部分の最短放電空間距離ｄ２を２ｍｍにして、各ランプの始動電圧を測定した所、図１２に示すような関係を得た。
【００２７】
図１３は、照射器３の窓面照度４０ｍＷ／ｃｍ^２を確保するようにキセノンガス圧を５３，３００Ｐａ（４００ｔｏｒｒ）で一定にした場合の、くびれ８部分の最短放電空間距離ｄ２と当該エキシマランプの始動電圧の関係を示したものである。くびれ８部分の最短放電空間距離ｄ２は短くすればするほど、当該エキシマランプの始動電圧を低下させるのに効果があるが、くびれ８の先端部分に始動パルスエネルギーが集中し過ぎてその部分の石英ガラスに損傷が発生し、そこから放電ガラス容器がリークする恐れがあり、当該エキシマランプの寿命２，０００時間を保証するには、最短放電空間距離ｄ２は２ｍｍが最適である。
【００２８】
このように、本発明の構成を有する電界結合型高周波エキシマランプにおいては、図８に示す照射器に装着した場合に窓面６の照度４０ｍＷ／ｃｍ^２を得ることができるようにキセノンガス圧を５３，３００Ｐａ（４００ｔｏｒｒ）とし、始動器１２から発生するパルスピーク電圧が６ｋＶ、パルス幅が５０μｓｅｃという条件で安定に放電させる事ができた。従って、従来の始動電圧（２５ｋＶ）の約１／４のパルスピーク電圧で始動させる事ができたことになる。
【００２９】
【発明の効果】
以上述べたように、本発明の放電ランプにおいては、放電ガスを封入したガラス容器の一部または全周にへこみ若しくはくびれを配設したので、始動電圧を従来よりも大幅に低減させることができる。特に、灯体部の形状が中空円筒状である電界結合型高周波エキシマランプにおいて大きな効果を奏する。
【００３０】
また、本発明の放電ランプにおいては、始動のためのパルスピーク電圧が小さいので、始動電極５及びその口出９よりコロナ放電や縁面放電を誘発することがなく、かつ始動が安定し、さらに照射器内の安全性、即ち絶縁性が十分に確保されるという効果も発揮する。
【００３１】
なお、本発明の放電ランプにおいては、図８に示す照射器の窓面から放射されるスペクトル分布は従来型の放電ランプ（エキシマランプ）を装着した同照射器の窓面から放射されるスペクトル分布と全く同じであって、本発明の構成による影響は生じなかった。
【００３２】
上記の説明ではキセノンガスの作用について開示したが、同様のエキシマ光を発生するヘリウム、ネオン、アルゴン、クリプトンの希ガス類を封入した放電ランプの場合にも同様の作用があり、また、これらのガスに若干の塩素のようなハロゲンガスを添加した放電ランプにも同様の作用があり、同じ効果が得られる。
【００３３】
さらに、放電ガラス容器が円筒状でない一般の電界結合型高周波放電ランプとしての蛍光ランプや金属ハロゲン化物等を封入したメタルハライドランプ等の場合にも同様に作用し、始動電圧に関して同じ効果が得られる。
【００３４】
図３に示すエキシマランプは、外管１ａの端部の一部にへこみ１４を配設して始動のための放電空間距離を縮めた構造を具備し、同様に当該エキシマランプの始動電圧を低下させる効果があり、本発明の一部に含まれる。図４に示すエキシマランプは内管１ｂの内側にくびれ１５を配設し、始動電極５をそのくびれ１５に接触させた構造を有し、図５に示すエキシマランプは、外管１ａと内管１ｂの両方にくびれ１５、１６を配設し、前記のようにくびれ１５、１６にそれぞれ接触させて電極を配設した構造を有し、それぞれ同様の効果があり、本発明の一部に含まれる。
【図面の簡単な説明】
【図１】本発明に関わるエキシマランプの概略断面図。
【図２】本発明に関わるエキシマランプの外観図。
【図３】本発明の他の実施例のエキシマランプの概略断面図。（変形例１）
【図４】本発明の他の実施例のエキシマランプの概略断面図。（変形例２）
【図５】本発明の他の実施例のエキシマランプの概略断面図。（変形例３）
【図６】本発明に関わるエキシマランプの動作回路構成。
【図７】従来のエキシマランプの概略断面図。
【図８】公知の照射器の外観図。
【図９】従来の始動方式の動作回路構成。
【図１０】従来技術における、入力電力１７０Ｗの時のキセノンガス圧と窓面照度の関係を示すグラフ。
【図１１】従来技術における、入力電力１７０Ｗ、キセノンガス圧５３，３００Ｐａの時の放電空間距離と窓面照度の関係を示すグラフ。
【図１２】従来技術における、最短放電空間距離が２ｍｍの時のキセノンガス圧と始動電圧の関係を示すグラフ。
【図１３】従来技術における、キセノンガス圧５３，３００Ｐａの時の最短放電空間距離と始動電圧の関係を示すグラフ。
【符号の説明】
１… 灯体（ガラス容器）
１ａ… 外管
１ｂ… 内管
２… ガラス製水冷管
３… 外側主電極
４… 内側主電極
５… 始動電極
６… 窓面
７… エキシマランプ
８… くびれ
９… 始動電極口出
１０… 高周波電源
１０ａ… 高周波入力電力
１１、１２… 始動器
１３… 放電空間
１４… へこみ
１５… くびれ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention is particularly applicable to a starting voltage of an electric field-coupling discharge lamp in which an electrode is provided outside a glass container in which a discharge gas is sealed and a high-frequency voltage is applied to the electrode, that is, an E discharge lamp (so-called excimer lamp). The improvement to lower the
[0002]
[Prior art]
Generally, such a discharge is a glass container in which a rare gas such as neon, argon, xenon, krypton, or the like is sealed, and generally constitutes an electric field-coupling type electrodeless discharge in a synthetic quartz tube, and is generally disclosed in References 1 and 2. It is used in the construction of an excimer lamp that emits excimer light by applying an electrodeless discharge. In particular, an excimer lamp filled with xenon gas has a radiation spectrum distribution having a center wavelength of 172 nm and a half-value width of 14 nm. This ultraviolet light is particularly called vacuum ultraviolet light, and has a much shorter energy than the ultraviolet light of a wavelength of 185 nm or 254 nm emitted from a general low-pressure mercury lamp because the energy is much shorter. Therefore, active oxygen and ozone are often generated, and in particular, recently, they have been widely used for cleaning glass of liquid crystal elements and PDP elements, and have been used for surface processing of silicon wafers of semiconductor substrates.
[0003]
[Reference 1]
"Technical Trends of Electrodeless Discharge Lamps / Explanation of Electric Field Coupled Discharge E Discharge" Journal of the Illuminating Engineering Institute, Vol. 77, No. 5, p.
[0004]
[Reference 2]
O plus E, Vol. 22, No. 8,1022 to 1024 pages (2000)
[0005]
7 and 8 show a conventional general excimer lamp. This lamp comprises a cylindrical lamp 1 having a hollow made of synthetic quartz and a water cooling tube 2 made of glass penetrating through the hollow. The outer main electrode 3 is provided with a short-length electrode, that is, a starting electrode 5 and an outlet 9, on the surface of the glass water-cooled tube 2 on the surface close to the end surface of the lamp 1, and the center of the hollow inner surface of the lamp 1. A long inner main electrode 4 covering the whole in the axial direction is provided.
[0006]
As described above, as the applications are expanded and the cleaning efficiency is required, a higher output of such excimer light is required. The illuminance of the irradiator using the xenon excimer lamp is 8 mW / cm ^{2 at the} radiation window surface. Illuminance of 40 mW / cm ² or more (measured by an illuminometer according to the NIST standard) has been required.
[0007]
Therefore, as a method of achieving such high illuminance, conventionally, the energy range in which excimer light is emitted, that is, increasing the high-frequency input power in a range where visible light emission does not increase, or a hollow cylindrical structure as shown in FIG. The dimensions of the outer tube 1a and the inner tube 1b of the lamp body 1 are optimized, and the pressure of the rare gas to be enclosed (in this case, the xenon gas pressure) is optimized.
[0008]
That is, in the lamp of FIG. 7, the discharge space distance d1 was 11 mm, the total length was 280 mm, and the external net main electrode length was 240 mm. The xenon gas pressure was changed, and this lamp was mounted on the irradiator shown in FIG. Substitute enough. In the circuit configuration shown in FIG. 9, the illuminance of the illuminator window 6 when the xenon gas pressure is changed while the high-frequency input power 10a to the lamp is specified by the input to the power amplification of the high-frequency power supply 10 and is fixed at 170 W is It is shown in FIG. Here, when the gas pressure is changed from 53,300 Pa (400 torr) to 66,700 Pa (500 torr), the illuminance sharply increases. That is, the radiation intensity of the 172 nm excimer light increases.
[0009]
Next, with the lamp structure shown in FIG. 7, the xenon gas pressure is kept constant at 53,300 Pa, the inner diameter of the outer tube 1a is fixed to change the outer diameter of the inner tube 1b, and the irradiation shown in FIG. FIG. 11 shows the illuminance of the window 6 of the container. Thus, the illuminance is increased by increasing the discharge space distance d1.
[0010]
[Problems to be solved by the invention]
Here, when the xenon gas pressure is increased to, for example, 53,300 Pa to widen the discharge space, there is a disadvantage that the starting voltage for starting the electric field-coupling type electrodeless discharge shown here becomes high. With respect to the discharge breakdown voltage when an external starting electrode is used as in the lamp having the structure shown in FIG. 7, Paschen's law described in Reference 3, which is generally disclosed, is satisfied. And the discharge distance are in inverse proportion.
[0011]
[Reference 3]
"Introductory Course of Basic Electronic Engineering, Tohoku University Gas Discharge" (Kindai Kagakusha), 157 pages (1989)
[0012]
Here, in order to obtain the illuminance of the irradiator window 6 shown in FIG. 8 of 40 mW / cm ² or more with the lamp having the structure shown in FIG. 7, the xenon gas pressure is set to 53,300 Pa, and the inner surface of the outer tube 1a and the inner tube 1b are formed. When a distance from the outer surface, that is, a discharge space distance d1 is set to 11 mm and a discharge is performed by a circuit configuration including the starter 11 as shown in FIG. 9, a discharge breakdown voltage requires a pulse voltage of 25 kV or more. Applying such a high voltage to start an excimer lamp as shown in FIG. 7 induces a corona discharge or an edge discharge from the starting electrode surface 5 and the lead 9 and makes the starting unstable. In addition, there arises a problem that safety in the irradiator, that is, insulation cannot be ensured.
[0013]
The present invention has been made in view of such a point, and solves the problem caused by requiring such a high starting voltage in an electric field coupling type high-frequency excimer lamp, and aims at reducing the starting voltage. It is an object of the present invention to provide an excimer lamp in which the safety in the irradiator, that is, the insulating property is ensured by preventing the corona discharge and the edge discharge from the starting electrode surface from being induced, and the starting property is stabilized.
[0014]
[Means for Solving the Problems]
The present invention has the following configuration to solve the above problems. That is, the discharge lamp according to claim 1 is provided so that a glass container filled with a discharge gas, a dent or constriction provided on a part or the entire circumference of the glass container, and an outer surface of the dent or constriction are provided. And an electrode disposed in contact with the outer surface of the glass container at a position facing the electrode.
[0015]
According to a second aspect of the present invention, there is provided the discharge lamp according to the first aspect, wherein a pair of high-frequency power supply electrodes are provided at positions facing each other on the outer surface of the glass container.
[0016]
The discharge lamp according to claim 3 is the discharge lamp according to claim 1 or 2, wherein the electrode disposed in contact with the outer surface of the dent or constriction and the outer surface of the glass container at a position facing the electrode. It is characterized in that a high-voltage pulse is applied between the electrodes arranged in such a manner.
[0017]
The discharge lamp according to claim 4 is the discharge lamp according to any one of claims 1 to 3, wherein the electrode disposed in contact with the outer surface of the dent or the constriction and the high-frequency electrode disposed in contact with the outer surface of the glass container. It is characterized in that it is connected to one of the power supply electrodes.
[0018]
The discharge lamp according to claim 5, wherein in the discharge lamp according to claim 1, the discharge gas filled in the glass container is one kind of gas selected from xenon, neon, helium, argon, and krypton, or a mixture of plural kinds of gases. It is characterized by being.
[0019]
According to a sixth aspect of the present invention, in the discharge lamp according to the first or fifth aspect, the substance sealed in the glass container is the discharge gas and one or more selected from chlorine, bromine, fluorine, and iodine. It is characterized by being a seed. It is characterized in that a metal halide is added in the glass container.
[0020]
According to a seventh aspect of the present invention, in the discharge lamp according to the first or fifth aspect, a metal halide is added to the inside of the glass container.
[0021]
The discharge lamp according to claim 8 is the discharge lamp according to any one of claims 1 to 7, wherein a dent or a constriction is provided on an outer surface of the glass container at a position facing an electrode disposed in contact with the dent or the constriction. And the other electrode is disposed so as to be in contact therewith.
[0022]
A discharge lamp according to a ninth aspect is characterized in that, in the discharge lamp according to the first, second, or seventh aspect, the glass container is made of quartz.
[0023]
According to a tenth aspect of the present invention, in the discharge lamp according to the first to ninth aspects, the glass container has a portion surrounded by a pair of coaxial cylindrical surfaces and a pair of parallel surfaces orthogonal to a central axis of the cylinder. The high-frequency power supply electrode has a three-dimensional shape approximated to a thick hollow cylinder having a cylindrical shell corresponding to a region, and the high-frequency power supply electrodes are respectively disposed on an outer cylindrical inner surface and an inner cylindrical inner surface of the hollow cylinder, and the recess is provided. Alternatively, the constriction is provided on the outer surface of the hollow cylinder.
[0024]
A discharge lamp according to an eleventh aspect is characterized in that, in the discharge lamp according to the first to tenth aspects, a net-shaped electrode is disposed on an outer cylindrical outer surface of the hollow cylindrical glass container.
[0025]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic sectional view including a central axis of an electric field coupling type high frequency excimer lamp constituting the present invention, and FIG. 2 is an external view thereof. The glass containers constituting the lamp are all made of synthetic quartz. Both ends of an outer tube 1a obtained by subjecting a quartz tube having an outer diameter of 35 mm, an inner diameter of 33 mm, and a length of 280 mm to a constriction in the vicinity of an end in advance and an inner tube 1b having an outer diameter of 11 mm, an inner diameter of 9 mm, and a length of 280 mm are joined. Thus, one closed discharge vessel as a whole, that is, the lamp body 1 is formed. The main discharge space distance d1 is 11 mm. The opening of the constriction 8 is processed to have a width of 10 mm, and the quartz wall thickness of the concavity 8 processing part is set to 1 mm, and the shortest discharge space distance d2 formed by the tip of the constriction 8 and the inner tube 1b is set to 2 mm. Xenon gas having a pressure of 53,300 Pa (400 torr) is sealed in the discharge space 13. On the outer surface of the glass water-cooled tube 2 penetrating the hollow inside the inner tube 1b, a starting electrode and its outlet in the form of a metal foil covering the outer surface near the end including the position facing the constriction 8 of the outer tube 1a. 9 and an inner main electrode 4 that covers substantially the entire outer surface other than that. A net-shaped outer main electrode 3 is provided on the outer surface of the outer tube 1a so as not to block radiated light. Further, the net-shaped outer main electrode 3 is disposed so as to sufficiently contact the outer surface of the concave portion of the constriction 8 of the outer tube 1a. Cooling water flows through the glass water cooling tube 2. As shown in the circuit configuration of FIG. 6, a high frequency power supply 10 having a frequency of 2.4 MHz and a pulse peak voltage of 4 kV is connected between the outer main electrode 3 and the inner main electrode 4. A starter 12 for generating a high voltage pulse is connected between the outer main electrode 3 and the starting electrode 5.
[0026]
Next, in order to examine the relationship between the starting voltage and the xenon gas pressure, an electric field coupling type having a structure similar to that of FIG. 1 and having a xenon gas pressure of 13,300 Pa (100 torr), 26,600 Pa (200 torr), 66,500 Pa (500 torr). A high-frequency excimer lamp was manufactured, and a high-frequency power supply 10 having a frequency of 2.4 MHz and a pulse peak voltage of 4 kV and a starter 12 having a pulse width of 50 μsec were connected in accordance with the circuit configuration shown in FIG. 6, and the shortest discharge space distance d2 of the constricted portion 8 was 2 mm. Then, when the starting voltage of each lamp was measured, the relationship as shown in FIG. 12 was obtained.
[0027]
FIG. 13 shows the shortest discharge space distance d2 of the constriction 8 and the excimer lamp when the xenon gas pressure is kept constant at 53,300 Pa (400 torr) so as to secure the illuminance of the window surface of the irradiator 3 at 40 mW / cm ^2. 3 shows the relationship between the starting voltages. The shorter the shortest discharge space distance d2 of the constriction 8 is, the more effective the lowering of the starting voltage of the excimer lamp is, but the starting pulse energy is concentrated too much on the tip of the constriction 8 and the quartz of that portion is The glass may be damaged, and the discharge glass container may leak therefrom. In order to guarantee the life of the excimer lamp of 2,000 hours, the shortest discharge space distance d2 is optimally 2 mm.
[0028]
As described above, in the electric field coupling type high-frequency excimer lamp having the configuration of the present invention, the xenon gas pressure is set so that the illuminance of the window surface 6 can be obtained at 40 mW / cm ² when mounted on the irradiator shown in FIG. It was possible to discharge stably under the conditions of 53,300 Pa (400 torr), a pulse peak voltage generated from the starter 12 of 6 kV, and a pulse width of 50 μsec. Therefore, it can be started with a pulse peak voltage of about 1/4 of the conventional starting voltage (25 kV).
[0029]
【The invention's effect】
As described above, in the discharge lamp of the present invention, since the dent or constriction is provided on a part or the entire circumference of the glass container filled with the discharge gas, the starting voltage can be significantly reduced as compared with the related art. . In particular, a great effect is obtained in an electric field coupling type high frequency excimer lamp in which the shape of the lamp body is a hollow cylindrical shape.
[0030]
Further, in the discharge lamp of the present invention, since the pulse peak voltage for starting is small, no corona discharge or edge discharge is induced from the starting electrode 5 and the outlet 9 thereof, and the starting is stable, and The effect that the safety in the irradiator, that is, the insulating property is sufficiently ensured is also exerted.
[0031]
In the discharge lamp of the present invention, the spectral distribution radiated from the window of the irradiator shown in FIG. 8 is the spectral distribution radiated from the window of the irradiator equipped with a conventional discharge lamp (excimer lamp). This is exactly the same as above, and no influence was caused by the configuration of the present invention.
[0032]
In the above description, the action of xenon gas is disclosed.However, a discharge lamp in which a rare gas such as helium, neon, argon, and krypton that generates the same excimer light has a similar action, and these gases are also used. A discharge lamp to which a slight amount of a halogen gas such as chlorine is added has a similar effect, and the same effect is obtained.
[0033]
Further, the same effect is obtained in the case of a fluorescent lamp or a metal halide lamp in which a metal halide or the like is sealed as a general electric field coupling type high frequency discharge lamp in which the discharge glass container is not cylindrical, and the same effect is obtained with respect to the starting voltage.
[0034]
The excimer lamp shown in FIG. 3 has a structure in which a recess 14 is provided at a part of the end of the outer tube 1a to reduce the discharge space distance for starting, and similarly, the starting voltage of the excimer lamp is reduced. And is included in a part of the present invention. The excimer lamp shown in FIG. 4 has a structure in which a constriction 15 is disposed inside the inner tube 1b, and the starting electrode 5 is in contact with the constriction 15. The excimer lamp shown in FIG. 1b has a structure in which the constrictions 15 and 16 are disposed on both sides, and the electrodes are disposed in contact with the constrictions 15 and 16 as described above. It is.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view of an excimer lamp according to the present invention.
FIG. 2 is an external view of an excimer lamp according to the present invention.
FIG. 3 is a schematic sectional view of an excimer lamp according to another embodiment of the present invention. (Modification 1)
FIG. 4 is a schematic sectional view of an excimer lamp according to another embodiment of the present invention. (Modification 2)
FIG. 5 is a schematic sectional view of an excimer lamp according to another embodiment of the present invention. (Modification 3)
FIG. 6 is an operation circuit configuration of an excimer lamp according to the present invention.
FIG. 7 is a schematic sectional view of a conventional excimer lamp.
FIG. 8 is an external view of a known irradiator.
FIG. 9 shows an operation circuit configuration of a conventional starting method.
FIG. 10 is a graph showing a relationship between xenon gas pressure and window surface illuminance at an input power of 170 W in the related art.
FIG. 11 is a graph showing the relationship between the discharge space distance and the illuminance of the window surface when the input power is 170 W and the xenon gas pressure is 53,300 Pa in the conventional technology.
FIG. 12 is a graph showing the relationship between the xenon gas pressure and the starting voltage when the shortest discharge space distance is 2 mm in the prior art.
FIG. 13 is a graph showing the relationship between the shortest discharge space distance and the starting voltage when the xenon gas pressure is 53,300 Pa in the related art.
[Explanation of symbols]
1. Lighting body (glass container)
1a ... outer tube 1b ... inner tube 2 ... glass water cooling tube 3 ... outer main electrode 4 ... inner main electrode 5 ... starting electrode 6 ... window surface 7 ... excimer lamp 8 ... constriction 9 ... starting electrode outlet 10 ... high frequency power supply 10a ... High frequency input power 11, 12 ... Starter 13 ... Discharge space 14 ... Dent 15 ... Constriction

Claims

A glass container filled with a discharge gas, a dent or constriction disposed on a part or the entire periphery of the glass container, an electrode disposed in contact with the outer surface of the dent or constriction, and a position facing the electrode. A discharge lamp comprising: an electrode disposed in contact with the outer surface of the glass container.

2. The discharge lamp according to claim 1, wherein a pair of high-frequency power supply electrodes are provided at positions on the outer surface of the glass container facing each other. 3.

A high-voltage pulse is applied between the electrode disposed in contact with the outer surface of the dent or constriction and the electrode disposed in contact with the outer surface of the glass container at a position facing the electrode. The discharge lamp according to claim 1 or 2.

An electrode arranged in contact with the outer surface of the dent or constriction and one of the high-frequency power supply electrodes arranged in contact with the outer surface of the glass container are connected to each other. Item 10. A discharge lamp according to item 3.

2. The discharge lamp according to claim 1, wherein the discharge gas sealed in the glass container is one kind of gas selected from xenon, neon, helium, argon, and krypton, or a mixture of plural kinds of gases.

6. The discharge lamp according to claim 1, wherein the substance to be sealed in the glass container is the discharge gas and one or more kinds selected from chlorine, bromine, fluorine and iodine. .

6. The discharge lamp according to claim 1, wherein a metal halide is added to the glass container.

On the outer surface of the glass container at a position facing the electrode disposed in contact with the dent or constriction, a dent or constriction is disposed, and the other electrode is disposed in contact therewith. The discharge lamp according to claim 1, wherein the discharge lamp is used.

8. The discharge lamp according to claim 1, wherein the glass container is made of quartz.

The glass container has a three-dimensional shape approximating a thick hollow cylinder having a cylindrical shell, which corresponds to a region surrounded by a pair of coaxial cylindrical surfaces and a pair of parallel surfaces orthogonal to the central axis of the cylinder. The said high frequency power supply electrode is each arrange | positioned at the outer cylinder outer surface and the inner cylinder inner surface of the said hollow cylinder, The said dent or constriction was arrange | positioned at the outer surface of the hollow cylinder. A discharge lamp according to claim 9.

The discharge lamp according to any one of claims 1 to 10, wherein a net-like electrode is provided on an outer cylindrical outer surface of the hollow cylindrical glass container.