1335606 九、發明說明 【發明所屬之技術領域】 本發明是關於介於介質材料使之放電而進行受激準分 子發光的受激準分子燈；尤其是，關於在放電空間內具有 內部電極的受激準分子燈》 【先前技術】 作爲關連於本發明的技術，有例如日本特開平2 - 7 3 5 3 號’在該公報中揭示著在放電容器塡充形成受激準分子的 放電用氣體，利用經由介質進行放電俾將受激準分子生成 在放電容器內的放電用氣體，取出從該受激準分子所放出 的受激準分子燈。 也眾知該受激準分子燈是具有在習知低壓水銀放電燈 或高壓放電壓所沒有的強烈地放射單一波長的紫外光等的 特徵。作爲使用受激準分子燈的發光裝置，除了上述公報 以外，例如揭示於日本專利第2854255號，及日本特開 2002-168999 號等。 揭示於上述日本專利第2854255號及日本特開2002-1 6 8 999號的受激準分子燈（介質障壁放電燈），是形成 在圓筒狀內側管的外側同軸地配置有相同圓筒狀外側管的 雙重圓筒型構造，在外側管外面配置有外側電極，而在內 側管內部配設有內部電極，將形成於外側管與內側管之間 的空間作爲放電空間者。 在第7圖表示上述習知的受激準分子燈的槪略構成。 -5- (2) (2)1335606 第7 (a)圖是表示整體的橫斷面圖；第7(b)圖是表示第 7 (a)圖的A-A斷面圖。 受激準分子燈60是整體形狀爲圓筒狀而由合成石英 玻璃所構成。放電燈6 0是外側管61與內側管6 2同軸地 配置而構成雙重圓筒管，同時封閉兩端而在外側管61與 內側管6 2之間形成有放電空間S。在放電空間S藉由介 質障壁放電來形成受激準分子，同時封入有從該受激準分 子放射真空紫外光的如氙氣體的放電氣體。 在外側電極61的外面設有其中一方的電極的網狀外 側電極63，而在內側管62的內部設有另一方的電極的內 部電極64。 在外側電極63與內部電極64之間，連接有未圖示的 交流電源，由此，在放電空間形成有受激準分子而發光紫 外光。放電用氣體是因示於發光波長而被選擇，例如使用 氙氣體時則放射波長172nm的光。 然而，在該構造的受激準分子燈，有 （1)將所謂內 側管，外側管的兩支石英玻璃管作成雙重圓筒型之故，因 而使將放電容器整體變大，又，內側管是在端部被焊著支 持，因此受到重力影響而容易受損，（2)成爲需要在兩 端部接合兩支石英玻璃管所用的製品，而該製程是複雜又 煩雜，（3)內側管是比可冷卻的外側管成爲高溫，會受 到熱膨脹所致的大負載，尤其是，應力會集中在與外側管 的接合部而容易受損，燈愈長其影響愈嚴重等缺點問題。 又，並不是雙重圓筒型，而是如日本專利3506055號 (3) (3)1335606 所示地’也存在著內部電極具有朝放電空間內延設的構造 的受激準分子燈。該構造是放電容器由一個圓筒體所成， 而未存有相當於雙重圓筒型的內側管者，因此可解決上述 缺點問題的幾個問題。 然而，在該構造的受激準分子燈中，內部電極露出於 放電空間內而電極直接作用於放電空間，因此有（1)由 電極所生成的放電的空間分布容易成爲不均勻，（2)若 未注意對於供電極性’會生成電弧狀放電而無法有效率地 生成受激準分子光’ （3)若形成有電弧狀放電，則該部 分會燒紅而燒斷電極，（4)由電極金屬進行濺鍍，會污 染放電容器的光取出部等其他缺點問題。 專利文獻1 :日本特開平2 - 7 3 5 3號 專利文獻2:日本專利第2854255號 專利文獻3:日本特開2002-168999號 專利文獻4:日本專利第3506055號 【發明內容】 本發明欲解決的課題，是在於提供一種受激準分子燈 ’可避免雙重圓筒型受激準分子燈所具有的構造複雜性， 且具有藉由端部被開放的介質覆蓋能夠避免內部電極直接 露出於放電空間內的構造的受激準分子燈所具有的放電不 方便等的放電空間內的內部電極的新穎構造者。 本發明的受激準分子燈，是被封入有放電用氣體的放 電容器’及朝長度方向延伸該放電容器的內部而且在放電 (4) (4)1335606 容器的端部被氣密地密封的內部電極’及配置在放電容器 外面的外側電極所成的受激準分子燈’其特徵爲；上述內 部電極是至少與外側電極之間進行放電的部位的外表面， 藉由至少一端被開放在放電空間內的介質材料所成的內側 管所覆蓋，而且該內側管是朝長度方向超越延伸所對應的 外側電極端部，在其端部具有防止從上述內側管所突出的 內部電極與外側電極之間的不期望的沿面放電的沿面放電 防止裝置。 又，上述沿面放電防止裝置是沿面距離延長裝置，爲 其特徵者。 又，上述沿面放電防止裝置是減少被積蓄在內側管端 部近旁的外表面的電荷的電荷減少裝置，爲其特徵者。 本發明的受激準分子燈，是在內部電極外周設有介質 材料所成的內側管，成爲兩個介質介於內部電極與外側電 極之間，因此放電能夠均勻地形成在放電空間。又，儘管 供電極也不會生成電弧狀放電，因此受激準分子光的生成 效率較高，也不會發生電極被燒斷的不方便。 此外，在內側管端部設有沿面放電防止裝置，因此防 止在從上述內側管所突出的內部電極與外側電極之間的不 期望的沿面放電，能夠得到內側管內的內部電極與外側電 極之間的穩定放電。 【實施方式】 以下使用第1圖至第6圖說明本發明的受激準分子燈 -8- (5) (5)1335606 的實施例。 (實施例1) 第1 (a)圖是表示朝長度方向切剖本發明的受激準分 子燈所得到的側斷面圖。第1 (b)圖是表示第1 (a)圖的 橫斷面圖；第2圖是表示主要部分A的擴大圖。 受激準分子燈1是具有如合成石英玻璃的介質材料所 成的放電容器2，該放電容器是具備整體爲管狀的發光部 21’及氣密地密封其兩端的發光部21的密封部22;在該 發光部21內形成有發光空間S，並塡充著放電氣體。 在放電容器2的內部配置有線圈狀內部電極3成爲沿 著放電容器2的管軸X，而在放電容器2的外表面配設有 外側電極4。內部電極3兩端的內部引線6是分別連接於 被埋設在被箍縮密封的密封部22的金屬箔7的一端，而 在該金屬箔7的另一端從密封部22朝外方延伸般地連接 有外部引線8。 在內部電極3的外周，能夠覆蓋該內部電極般地設有 介質材料所成的內側管5。該內側管5是在放電空間S內 開放著其兩端，至少在內部電極3與上述外側電極4之間 進行放電的部位被覆蓋，而在軸向超過外側電極4延伸著 〇 該內側管5是由未圖示的支持體被支持在發光部21 者也可以，或是同樣地由未圖示的支持體被支持在內部電 極3者也可以。 -9- (6) (6)1335606 如此，在形成於發光部21的內部的放電空間s，封 入有藉由介設介質材料的放電作爲形成受激準分子所用的 如氣氣體的放電用氣體。 又，內部電極3是表不線圈狀者，惟並不被限定於此 者，也可以爲桿狀，棒狀者。但是作爲內部電極3採用線 圈狀電極，則對於軸向的熱膨具有緩衝功能，吸收與石英 玻璃所成的放電容器2的熱脹差，具有可防止密封部22 發生裂縫的優點。 又，對於外側電極4，在圖示的例中，也以半圓筒體 形所例示，惟並不被限定於此，當然如網狀電極等的圓筒 狀透光性電極也可以。 又，密封部22的構造是並不被限定在箍縮密封者， 其他的箔密封，亦即收縮密封構造也可以，或是也可採用 所謂對搭接密封。對搭接密封的優點是玻璃與電極的接合 性變成良好，更確實地可防止密封部的氣體洩漏或發生裂 縫。 如第2圖所詳示地’在內側管5的端部近旁，形成有 喇叭狀地逐漸擴大其徑的擴徑部5 1。該擴徑部5 1是功能 作爲沿面放電防止裝置者’用以增加從外側電極4的端部 一直到內部電極3的沿面距離者。因此，該擴徑部51是 超過延伸外側電極4而設在密封部2 2側，該設置位置或 大小是被選擇成未覆蓋於外側電極4與內部電極3的內側 管5的部位31之間不會發生不期望的沿面放電。 在圖示的例中，沿面距離L是成爲在發光部21的內 -10- (7) 1335606 周面中從相當於外側電極4的端部E的位置A至相 側管5的E的位置爲止的距離L1，及從B至擴徑若 端部C爲止的沿著擴徑部51的外表面的距離L2, 至對於內部電極3的最短距離的位置D爲止的距寵 合計 （L = L1+L2 + L3)。因此，與全長相同而與未 徑徑部的構造者相比較，藉由相加從C至D爲止 L3分量而可伸長沿面距離。 又，上述擴徑部51是並不被限定於圖示的喇 而是推拔狀或階段狀的擴徑部也可以，主要爲與直 相比較若爲相加距離的構造，則其他構造也可以。 在內部電極3與外側電極4連接有未圖示的高 ，在兩電極間介設介質材料的放電容器2及內側管 生介質障壁放電，俾產生受激準分子發光。 在本發明的受激準分子燈中，內側管5伸長至 22，而被埋設在密封部22並不理想。若內側管5 在密封部22，則會產生與在先行技術所說明的雙重 構造的受激準分子燈同樣的缺點問題。 如上所述地，依照表示於第1圖及第2圖的構 激準分子燈，擴徑部成於內側管端部爲最大特徵， 明其優點。 本發明的受激準分子燈是內側管藉由如上述的 未被埋設密封部，且內部電極的端部附近未被覆蓋 管而直接被曝露在放電用氣體的構造。因此，若在 於外側電極的端部與內部電極的內側管的部位之間 當於內 15 5 1 的 及從C :L3的 具有擴 的距離 叭狀， 管狀者 頻電源 5而發 密封部 被埋設 圓筒型 造的受 以下說 理由而 在內側 未覆蓋 未充分 -11 - (8) (8)1335606 地確保距離（稱爲沿面距離，則在兩者之間會產生不期望 的沿面放電，由此，會產生失去在內外電極間的放電穩定 性的不方便。詳細地，此種沿面放電是可能爲朝從內側管 所突出的內部電極對應於內側管的外側電極端部的部位發 生者。 爲了防止此而充分地採取沿面距離，若僅對於外側電 極增加內側管長度，與覆蓋於內側管的內部電極與外側電 極之間的有效放電形成部分的長度相比較會增加放電容器 的全長度，換言之，放電形成部分對於燈全長所佔的比率 較少，因此不理想。 對於此，依照在內側管5的端部形成擴徑部51的本 發明的受激準分子燈的構造，藉由存在擴徑部51成爲延 伸沿面距離，不會過剩地縮短放電形成部分而可確保充分 的沿面距離，並可確實地防.止發生不期望的沿面放電。 將表示於第1圖的受激準分子燈1的數値例表示於如 下。 放 電容器 2是全長 (包含密封部 22) 2 2 0m m 至 2 7 0 0mm ，例如 1 620mm; 發光部21的全長是 100m im 至 2 7 0 0mm ，例如 1 5 0 0mm; 外徑是 l〇mm至 50mm， 例如 16mm， 內徑是 8mm 至 48r nm，例如 1 4mm。 內部電極3是全長190mm至2790mm，例如1590mm; 外徑是1mm至40mm，例如3mm;間距是0.5mm至10mm ，例如2 m m。 內側管5是全長170mm至2700mm，例如1570mm; -12- (9) (9)1335606 外徑是2mm至42mm，例如4mm;內徑是1mm至40mm， 例如3 m m。擴徑部5 1是最大外徑是4 m m至4 6 m m，例如 12mm。其他，外側電極4的全長是100mm至2700mm， 例如 1 5 0 0 m m。 沿面距離L是3mm至150mm，例如80mm。 (實施例2) 第3圖是表示其他的沿面距離延長裝置者；在比外側 電極4端還位於外方的內側管5的端部近旁，設置非導電 性材料所成的隔間板1 0。該隔間板1 0是將石英玻璃或陶 瓷等非導性材料所成的其他構件焊著於內側管5，或是鼓 出內側管5本體所形成也可以。 依照表示於第3圖的受激準分子燈1，在沿面距離L 相當於各隔間構件1 0的高度Η的距離成爲對應於隔間構 件1〇的個數而被相加。因此，不會減少放電形成部分對 於燈全長的所佔比率使得沿面距離L伸長，因此良好地可 防止發生對於從外側電極4未覆蓋於內側管5的內部電極 3的沿面放電》 有關於表示於第3圖的實施例2，表示與第1圖，第 2圖的實施例1不相同部分的數値例。隔間構件1 0是外徑 7mm至47mm，例如 13mm。內徑是2mm至42mm，例如 4mm。厚度（管軸X方向）是1mm至10mm，例如3mm。 沿面距離L是在設置兩件隔間構件10時爲3mm至150mm ，例如8 0 m m。 -13- (10) 1335606 (實施例3) 表示於第4圖至第6圖來作爲沿面放電防止裝置，採 用減少發生在內側管5的端部外表面的電荷量的電荷減少 裝置的情形。 在第4圖的實施例3中，將介質11藉由焊著等附加 地安裝於內側管5的端部外表面。作爲該附加介質1 1，與 內側管5相同材料者較理想’內側管5爲石英玻璃時，附 加介質1 1也是石英玻璃。這時候，內側管5是在端部近 旁與其他部分相比較也可使其厚度作成較厚。 藉由構成如此，被積蓄在內側管5的端部厚度部11 的外表面的電荷，是與內側管5的其他部分的電荷相比較 變成較少，因此，從外側電極4的端部不容易放電傳至內 側管5外的內部電極3，而可防止沿面放電者。 (實施例4) 在第5圖中，該實施例4是與上述實施例3基本上想 法相同，該實施例的情形，爲被連結於內部電極3的內部 引線6延伸到內側管5的內部的情形。在該實施例中’設 於內側管5的端部的附加介質1 2是設於內側管5的內表 面。 有關於該實施例4的沿面放電防止的作用是與上述實 施例3同樣，惟僅內側管5的外表面ί乍成2F '滑化之處不相 同。 -14- (11) (11)1335606 (實施例5) 在第6圖表示實施例5 ’第6 (a)圖是表示側斷面圖； 第6 (b)圖是表示橫斷面圖。 在第6圖中’在內側管5的端部近旁，捲繞著金屬線 或金屬線等的導電構件13，而其他端部13R是朝放電容 器2的內壁方向伸長者，抵接於放電容器2也可以。 在該實施例中，積蓄於內側管5的端部外表面的電荷 ，經由導電構件1 3從另一端部1 3a避開至放電容器2側 ，因此結果，減少被積蓄於端部外表面的電荷。所以，防 止從外側電極4的端部對於內側管5外的內部電極3的沿 面放電。 【圖式簡單說明】 第1 (a)圖至第1 (b)圖是表示本發明的實施例1的 圖式。 第2圖是表示第1圖的局部放大圖。 第3圖是表示實施例2的圖式。 第4圖是表示實施例3的圖式。 第5圖是表示實施例4的圖式。 第6 (a)圖及第6 (b)圖是表示實施例5的圖式。 第7 (a)圖及第7(b)圖是表示習知例的圖式。 【主要元件符號說明】 1:受激準分子燈，2:放電容器，21:發光部，22:密封 -15- (12) 1335606 部，3 :內部電極，4 :外側電極，5 :內側管，5 1 :擴徑部，6 : 內部引線，7:金屬箔，8:外部引線，10:隔間板，1 1，12: 附加介質（端部厚度部），13:導電構件。 -16-1335606 IX. Description of the Invention [Technical Field] The present invention relates to an excimer lamp that emits excimer light by being discharged by a dielectric material; in particular, with respect to having an internal electrode in a discharge space Excimer light lamp [Prior Art] As a technique related to the present invention, for example, Japanese Patent Laid-Open No. Hei 2-7 3 5 No. 3 discloses that a discharge gas for forming an excimer in a discharge vessel is disclosed in the publication. The discharge gas generated by the excimer in the discharge vessel is discharged by discharging the medium through the medium, and the excimer lamp emitted from the excimer is taken out. It is also known that the excimer lamp is characterized by having a strong emission of a single wavelength of ultraviolet light or the like which is not provided by a conventional low-pressure mercury discharge lamp or a high-voltage discharge voltage. As a light-emitting device using an excimer lamp, in addition to the above-mentioned publication, for example, Japanese Patent No. 2854255, Japanese Patent Laid-Open No. 2002-168999, and the like are disclosed. An excimer lamp (dielectric barrier discharge lamp) disclosed in Japanese Patent No. 2854255 and Japanese Patent Laid-Open Publication No. 2002-1 6 999 is formed on the outer side of the cylindrical inner tube and coaxially arranged in the same cylindrical shape. In the double cylindrical structure of the outer tube, an outer electrode is disposed on the outer surface of the outer tube, and an inner electrode is disposed inside the inner tube, and a space formed between the outer tube and the inner tube is used as a discharge space. Fig. 7 shows a schematic configuration of the above-described conventional excimer lamp. -5- (2) (2) 1335606 Fig. 7(a) is a cross-sectional view showing the whole; and Fig. 7(b) is a cross-sectional view taken along line A-A of Fig. 7(a). The excimer lamp 60 has a cylindrical shape as a whole and is composed of synthetic quartz glass. The discharge lamp 60 is disposed such that the outer tube 61 and the inner tube 6 2 are coaxially arranged to form a double cylindrical tube, and both ends are closed, and a discharge space S is formed between the outer tube 61 and the inner tube 62. An excimer is formed in the discharge space S by dielectric barrier discharge, and a discharge gas such as helium gas which emits vacuum ultraviolet light from the excited molecule is enclosed. A mesh-shaped outer electrode 63 of one of the electrodes is provided on the outer surface of the outer electrode 61, and an inner electrode 64 of the other electrode is provided inside the inner tube 62. An AC power source (not shown) is connected between the outside electrode 63 and the internal electrode 64, whereby an excimer is formed in the discharge space to emit ultraviolet light. The discharge gas is selected based on the emission wavelength. For example, when a xenon gas is used, light having a wavelength of 172 nm is emitted. However, in the excimer lamp of this configuration, (1) the two quartz glass tubes of the so-called inner tube and the outer tube are formed into a double cylinder type, thereby making the entire discharge vessel large, and the inner tube It is supported at the end by welding, so it is easily damaged by gravity. (2) It is a product that needs to join two quartz glass tubes at both ends, and the process is complicated and complicated. (3) Inner tube It is a higher temperature than the outer tube that can be cooled, and is subjected to a large load due to thermal expansion. In particular, the stress is concentrated on the joint portion with the outer tube and is easily damaged, and the longer the lamp is, the more serious the influence is. Further, it is not a double cylinder type, but an excimer lamp having a structure in which an internal electrode has a structure extending toward a discharge space as shown in Japanese Patent No. 3506055 (3) (3) 1335606. This configuration is such that the discharge vessel is formed of a cylindrical body and there is no inner tube equivalent to the double cylinder type, so that several problems of the above disadvantages can be solved. However, in the excimer lamp of this configuration, the internal electrode is exposed in the discharge space and the electrode directly acts on the discharge space, so that (1) the spatial distribution of the discharge generated by the electrode is likely to be uneven, (2) If it is not noticed that the power supply polarity 'will generate an arc discharge and the excimer light cannot be efficiently generated' (3) if an arc discharge is formed, the portion will burn red and the electrode will be blown, and (4) the electrode Sputtering of the metal can contaminate other shortcomings such as the light extraction portion of the discharge vessel. Patent Document 1: Japanese Laid-Open Patent Publication No. Hei No. Hei. No. 2,854,255, Patent Document 2: Japanese Patent No. 2,854,255, Patent Document 3: Japanese Patent Laid-Open Publication No. No. No. No. No. No. No. No. No. No. The problem to be solved is to provide an excimer lamp that avoids the structural complexity of a double-cylinder excimer lamp and has a dielectric covering with an open end to prevent the internal electrode from being directly exposed. A novel constructor of an internal electrode in a discharge space, such as an excimer lamp having a structure in a discharge space, is inconvenient to discharge. The excimer lamp of the present invention is a discharge vessel that is sealed with a discharge gas and extends inside the discharge vessel in the longitudinal direction and is hermetically sealed at the end of the discharge (4) (4) 1335606 container. The internal electrode 'and the excimer lamp formed by the outer electrode disposed outside the discharge vessel' are characterized in that the internal electrode is an outer surface of a portion where at least the outer electrode is discharged, and at least one end is opened at The inner tube formed by the dielectric material in the discharge space is covered, and the inner tube is an outer electrode end portion corresponding to the extension in the longitudinal direction, and has an inner electrode and an outer electrode at the end portion thereof to prevent the inner tube from protruding from the inner tube. A creeping discharge prevention device between undesired creeping discharges. Further, the creeping discharge preventing device is a creeping distance extending device and is characterized by the above. Further, the creeping discharge preventing means is a charge reducing means for reducing electric charge accumulated on the outer surface of the inner tube end portion. The excimer lamp of the present invention is an inner tube formed of a dielectric material on the outer circumference of the internal electrode, and the two dielectrics are interposed between the internal electrode and the outer electrode, so that the discharge can be uniformly formed in the discharge space. Further, although the arc electrode does not generate an arc discharge, the generation efficiency of the excimer light is high, and the inconvenience that the electrode is blown does not occur. Further, since the creeping discharge preventing means is provided at the end portion of the inner tube, undesired creeping discharge between the inner electrode and the outer electrode protruding from the inner tube is prevented, and the inner electrode and the outer electrode in the inner tube can be obtained. Stable discharge between. [Embodiment] Hereinafter, an embodiment of an excimer lamp -8-(5)(5)1335606 of the present invention will be described using Figs. 1 to 6 . (Embodiment 1) Fig. 1(a) is a side sectional view showing the excimer lamp of the present invention cut along the longitudinal direction. Fig. 1(b) is a cross-sectional view showing a first (a) diagram, and Fig. 2 is an enlarged view showing a main portion A. The excimer lamp 1 is a discharge vessel 2 having a dielectric material such as synthetic quartz glass, and the discharge vessel is a sealing portion 22 having a light-emitting portion 21' which is entirely tubular and a light-emitting portion 21 which hermetically seals both ends thereof. A light-emitting space S is formed in the light-emitting portion 21, and a discharge gas is filled. The coil-shaped internal electrode 3 is disposed inside the discharge vessel 2 so as to be along the tube axis X of the discharge vessel 2, and the outer electrode 4 is disposed on the outer surface of the discharge vessel 2. The inner leads 6 at both ends of the internal electrode 3 are respectively connected to one end of the metal foil 7 embedded in the sealing portion 22 of the pinch seal, and are connected at the other end of the metal foil 7 so as to extend outward from the sealing portion 22. There are external leads 8. On the outer circumference of the internal electrode 3, an inner tube 5 made of a dielectric material can be provided so as to cover the internal electrode. The inner tube 5 is opened at both ends in the discharge space S, and at least a portion where the discharge between the internal electrode 3 and the outer electrode 4 is discharged is covered, and the inner tube 5 extends beyond the outer electrode 4 in the axial direction. The support unit (not shown) may be supported by the light-emitting unit 21, or may be supported by the internal electrode 3 by a support (not shown). -9- (6) (6) 1335606 In the discharge space s formed inside the light-emitting portion 21, a discharge gas by interposing a dielectric material is used as a discharge gas such as a gas gas for forming an excimer. Further, the internal electrode 3 is not a coil, but is not limited thereto, and may have a rod shape or a rod shape. However, when the coil electrode is used as the internal electrode 3, it has a buffering function for thermal expansion in the axial direction, and absorbs the difference in thermal expansion of the discharge vessel 2 made of quartz glass, thereby having the advantage of preventing cracks in the sealing portion 22. Further, the outer electrode 4 is exemplified by a semi-cylindrical shape in the illustrated example, but is not limited thereto, and may be a cylindrical translucent electrode such as a mesh electrode. Further, the structure of the sealing portion 22 is not limited to the pinch seal, and other foil seals, that is, a shrink seal structure may be used, or a so-called lap seal may be employed. The advantage of the lap seal is that the adhesion of the glass to the electrode becomes good, and it is more sure that the gas leakage or cracking of the seal portion is prevented. As shown in Fig. 2, in the vicinity of the end portion of the inner tube 5, an enlarged diameter portion 51 which gradually enlarges its diameter in a flared shape is formed. The enlarged diameter portion 51 is functional as a creeping discharge preventing device for increasing the creeping distance from the end portion of the outer electrode 4 to the internal electrode 3. Therefore, the enlarged diameter portion 51 is provided on the side of the sealing portion 22 beyond the extending outer electrode 4, and is disposed between the portion 31 of the inner tube 5 that is not covered by the outer electrode 4 and the inner electrode 3. Undesirable creeping discharge does not occur. In the illustrated example, the creeping distance L is a position from the position A corresponding to the end portion E of the outer electrode 4 to the E of the phase side tube 5 in the inner periphery of the light-emitting portion 21 -10 (7) 1335606 The distance L1 up to and the distance L2 from the B to the outer surface of the diameter-enlarged portion 51 from the end portion C to the position D of the shortest distance to the internal electrode 3 (L = L1) +L2 + L3). Therefore, the creeping distance can be extended by adding the L3 component from C to D as compared with the entire length and the structure of the non-diameter portion. Further, the diameter-enlarged portion 51 is not limited to the illustrated one, but may be a push-out or step-shaped enlarged diameter portion, and may be a structure in which the addition distance is mainly compared with the straight phase, and other structures are also can. A high voltage (not shown) is connected between the internal electrode 3 and the external electrode 4, and the discharge vessel 2 and the dielectric space barrier of the dielectric material interposed between the electrodes are discharged, and excimer light emission is generated. In the excimer lamp of the present invention, the inner tube 5 is elongated to 22, and it is not preferable to be buried in the sealing portion 22. If the inner tube 5 is in the sealing portion 22, the same disadvantages as the excimer lamp of the double structure described in the prior art are generated. As described above, according to the constitutive excimer lamp shown in Figs. 1 and 2, the enlarged diameter portion has the largest feature at the end portion of the inner tube, which is advantageous. In the excimer lamp of the present invention, the inner tube is directly exposed to the discharge gas by the unsealed sealing portion as described above, and the vicinity of the end portion of the internal electrode is not covered with the tube. Therefore, if the end portion of the outer electrode and the inner tube of the inner electrode are between the inner 15 15 1 and the C:L3, the tubular portion of the power source 5 is sealed. The cylindrical shape is not covered by the inside for the reasons described below. -11 - (8) (8) 1335606 ensures the distance (called the creeping distance, which causes an undesirable creeping discharge between the two. This causes inconvenience in that the discharge stability between the inner and outer electrodes is lost. In detail, such a creeping discharge may occur in a position where the internal electrode protruding from the inner tube corresponds to the outer electrode end portion of the inner tube. In order to prevent this from sufficiently taking the creeping distance, if the inner tube length is increased only for the outer electrode, the full length of the discharge vessel is increased as compared with the length of the effective discharge forming portion between the inner electrode and the outer electrode covering the inner tube. In other words, the discharge forming portion has a small ratio to the entire length of the lamp, and thus is not preferable. In view of this, the present invention according to the end portion of the inner tube 5 is formed with the enlarged diameter portion 51. In the structure of the excimer lamp, since the enlarged diameter portion 51 has an extended creeping distance, the discharge forming portion is not excessively shortened, and a sufficient creeping distance can be secured, and undesired creeping discharge can be surely prevented. The number of examples of the excimer lamp 1 shown in Fig. 1 is shown below. The discharge vessel 2 is the full length (including the sealing portion 22) 2 2 0 m m to 2 700 mm, for example, 1 620 mm; The total length is 100m im to 2 700mm, for example 1 500mm; the outer diameter is l〇mm to 50mm, for example 16mm, the inner diameter is 8mm to 48r nm, for example 14mm. The internal electrode 3 is 190mm to 2790mm in length, for example 1590mm; outer diameter is 1mm to 40mm, for example 3mm; spacing is 0.5mm to 10mm, for example 2mm. Inner tube 5 is full length 170mm to 2700mm, for example 1570mm; -12- (9) (9) 1335606 outer diameter is 2mm to 42 mm, for example 4 mm; inner diameter is 1 mm to 40 mm, for example 3 mm. The enlarged diameter portion 51 is a maximum outer diameter of 4 mm to 46 mm, for example 12 mm. Others, the outer electrode 4 has a total length of 100 mm to 2700 mm, for example 1 5 0 0 mm. The creeping distance L is 3 mm to 150 mm, for example 80 mm. (Example 2) Figure 3 is The other creeping distance extending device is shown; a partition plate 10 made of a non-conductive material is disposed near the end of the outer side inner tube 5 which is located outside the outer electrode 4 end. The partition plate 10 is Other members made of a non-conductive material such as quartz glass or ceramic may be welded to the inner tube 5 or may be formed by bulging the inner tube 5 body. According to the excimer lamp 1 shown in Fig. 3, the distance corresponding to the height Η of each of the compartment members 10 at the creeping distance L is increased in accordance with the number of the spacer members 1〇. Therefore, the ratio of the discharge forming portion to the total length of the lamp is not reduced so that the creeping distance L is elongated, so that the creeping discharge for the internal electrode 3 not covering the inner tube 5 from the outer electrode 4 is well prevented. The second embodiment of Fig. 3 shows a number of examples which are different from the first embodiment and the first embodiment of Fig. 2. The compartment member 10 is an outer diameter of 7 mm to 47 mm, for example, 13 mm. The inner diameter is from 2 mm to 42 mm, for example 4 mm. The thickness (tube axis X direction) is 1 mm to 10 mm, for example 3 mm. The creeping distance L is 3 mm to 150 mm, for example, 80 mm, when the two-piece spacer member 10 is provided. -13- (10) 1335606 (Embodiment 3) As shown in Figs. 4 to 6 as a creeping discharge preventing device, a charge reducing device for reducing the amount of electric charge generated on the outer surface of the end portion of the inner tube 5 is employed. In the third embodiment of Fig. 4, the medium 11 is additionally attached to the outer surface of the end portion of the inner tube 5 by welding or the like. As the additional medium 1, the same material as the inner tube 5 is preferable. When the inner tube 5 is quartz glass, the additional medium 1 is also quartz glass. At this time, the inner tube 5 can be made thicker than the other portions in the vicinity of the end portion. With this configuration, the electric charge accumulated on the outer surface of the end portion thickness portion 11 of the inner tube 5 is less compared with the electric charge of the other portion of the inner tube 5, and therefore, it is not easy from the end portion of the outer electrode 4 The discharge is transmitted to the internal electrode 3 outside the inner tube 5, and the creeping discharge can be prevented. (Embodiment 4) In Fig. 5, this embodiment 4 is basically the same as the above-described embodiment 3. In the case of this embodiment, the inner lead 6 connected to the internal electrode 3 extends to the inside of the inner tube 5. The situation. In this embodiment, the additional medium 12 provided at the end of the inner tube 5 is provided on the inner surface of the inner tube 5. The effect of the creeping discharge prevention of the fourth embodiment is the same as that of the above-described third embodiment, except that only the outer surface of the inner tube 5 is not 2F 'sliding. -14- (11) (11) 1335606 (Embodiment 5) Fig. 6 shows a fifth embodiment. Fig. 6(a) is a side sectional view, and Fig. 6(b) is a cross-sectional view. In Fig. 6, 'the conductive member 13 such as a metal wire or a metal wire is wound around the end of the inner tube 5, and the other end portion 13R is elongated toward the inner wall of the discharge vessel 2, and is abutted against the discharge. Container 2 is also available. In this embodiment, the electric charge accumulated on the outer surface of the end portion of the inner tube 5 is prevented from the other end portion 13a via the conductive member 13 to the discharge vessel 2 side, and as a result, the accumulated on the outer surface of the end portion is reduced. Charge. Therefore, the creeping discharge from the end portion of the outer electrode 4 to the inner electrode 3 outside the inner tube 5 is prevented. BRIEF DESCRIPTION OF THE DRAWINGS Figs. 1(a) to 1(b) are diagrams showing a first embodiment of the present invention. Fig. 2 is a partial enlarged view showing Fig. 1; Fig. 3 is a view showing the pattern of the second embodiment. Fig. 4 is a view showing the embodiment 3. Fig. 5 is a view showing the embodiment 4. Fig. 6(a) and Fig. 6(b) are diagrams showing the fifth embodiment. Figures 7(a) and 7(b) are diagrams showing a conventional example. [Description of main component symbols] 1: Excimer lamp, 2: discharge vessel, 21: light-emitting part, 22: seal -15- (12) 1335606, 3: internal electrode, 4: outer electrode, 5: inner tube , 5 1 : enlarged diameter, 6: inner lead, 7: metal foil, 8: outer lead, 10: compartment plate, 1, 1, 12: additional medium (end thickness portion), 13: conductive member. -16-