.201126568 六、發明說明： 【發明所屬之技術領域】 本發明係關於短弧型放電燈，尤其係關於適用於半導 體或液晶之製造領域等之曝光用光源或放映機之背光用光 源的短弧型放電燈。 【先前技術】 〇 短弧型放電燈係由於在發光管內相對向配置的一對電 極的前端距離較短而接近於點光源，因此藉由與光學系加 以組合而作爲曝光裝置用或放映機之背光用光源加以利用 0 專利文獻1係揭示習知技術之短弧型放電燈。根據該 文獻，已指出因氙短弧燈中作爲發光氣體的氙氣、水銀蒸 氣短弧燈中作爲緩衝氣體的氙氣、氪氣及氬氣所造成的準 分子發光，會引起在石英玻璃製放電容器的內面產生白濁 〇 的問題。此外，根據該文獻，以如上所示之問題的對策而 言’記載有：規定由該放電容器之紫外線放射發散度成爲 最大的部分的內面起200μιη之範圍的平均OH基濃度爲 7.8χ 1 0 24個/m3以上，而且由內面起深度20μιη之範圍的平 均ΟΗ基濃度爲1.5xl〇25個/m3以上、1·2χ 1 02 6個/m3以下 的內容。 但是，如上所示在發光管含有OH基，其在發光空間 內作爲Ηβ進行擴散，在發光管內擴散的H20係藉由來自 弧光的熱而被熱分解爲氧與氫。根據發明人等精心硏究的 -5- 201126568 結果，發現如上所示在發光管內生成的氫會使照度的安定 度降低。照度安定度的降低係由於弧光晃動，使對於光學 系統之光的入射量或入射角度分布產生變化。晃動的周期 雖依光學系統而異，但是會發生照度變動大致在數毫秒至 數秒之間變大的所謂閃爍。該照度安定度的降低在畫像投 影裝置中，會成爲畫面閃爍而造成問題，在曝光裝置則會 引起曝光不均的問題。 此外，在專利文獻2係揭示將用以吸收被放出至發光 管內之氫的集氫器配置在發光管內的內容。第10圖（a)係 顯示該文獻所記載之放電燈的槪略構成圖，第10圖（b)係 顯示第1 〇圖（a)所示之放電燈所配備之集氫器的剖面構造 圖。 第1 0圖（a)所示之放電燈係具備有：燈泡1 〇 1、電極 102、103、密封部104、金屬箔1〇5。106爲集氫器、107爲 石英棒、108爲石英筒。集氫器1〇6係如第10圖（b)所示， 圓筒狀之由釔所構成的集氫器材料109被密封在由钽等金 屬所構成之包含有底圓筒110與蓋部111的金屬外皮112的 內部。藉由使有底圓筒1 1 0的凸緣部1 1 0 A與蓋部1 1 1作阻 抗熔接’而將金屬外皮1 1 2的內部予以密封。集氫器1 06係 如第10圖（a)所示’收納有集氫器ι〇6的石英筒1〇8被固定 在燈泡101，藉由將設在石英筒1〇8的石英棒107的另一端 熔接在燈泡1 〇 1而固定在燈泡1 〇 1。燈泡1 0 1內的氣係通過 钽等具氫透過性的有底圓筒1 1 〇而侵入至內部，被集氫器 材料1 09所吸附。集氫器材料1 09係被密封在由有底圓筒 -6 - 201126568 110及蓋部111所構成的金屬外皮112的內部，因此防止集 氫器材料109與發光空間內的其他物質起反應，可效率佳 地吸附氫。 但是，該放電燈係將集氫器106安裝在燈泡101的構造 ，因此會有集氫器106與作爲燈泡101之構成成分的氧化矽 起反應的情形。藉此會有燈泡1 0 1失透明而導致照度降低 、或引起燈泡101破裂之虞。 0 此外，在專利文獻3係揭示一種將雜質氣體吸附構件 藉由熔接等而接著在電極的短弧放電燈。第11圖（a)、（b) 係分別記載於該文獻的陰極前端部的主要部位正面剖面圖 及俯視圖，電極201係在除了圓錐狀部分202以外的平行部 分，形成有具有直徑小於直徑d的細徑部2〇3。細徑部203 與線圈204之間的空處係被配設有由銷箔所構成的筒狀集 氣器205，利用熔接等適當的接著手段而被固定在細徑部 203 ° 〇 [先前技術文獻] [專利文獻] [專利文獻1]日本專利第2891997號 [專利文獻2]日本特公昭57-21835號 [專利文獻3 ]日本專利3 3 8 0 6 1 5號 【發明內容】 (發明所欲解決之課題） 本案發明人等係針對在將集氫器配設在發光管內時， 201126568 將第10圖所示之集氬器材料109的金屬外皮112，如專利文 獻3所示般’熔接在電極而予以固定的方法加以檢討。該 方法雖然發現對上述燈泡的失透明及破裂極爲有效，但是 當將金屬外皮熔接在電極時，預測出在熔接中會在金屬外 皮空出孔穴而使集氫器材料露出於發光管內，集氫器材料 與被封入在發光管內的水銀等發光物質起反應，而會使集 氫器材料的氫吸收功能降低。 本發明之目的在鑑於上述問題點，提供一種短弧型放 電燈，其係在發光管內的電極配備將吸收氫的集氫器予以 密閉’並且透過氫的中空容器的短弧型放電燈中，使前述 集氫器不會固定在電極而予以配備。 (解決課題之手段） 本發明爲了解決上述課題，請求項1所記載之發明係 一種短弧型放電燈’係在發光管內，將由本體部及與該本 體部連設的軸部所構成的一對電極彼此相對向配置，設置 在透過氫的中空容器內封入吸收氫的集氣器材料而成的集 氫器，該短弧型放電燈的特徵爲：在前述軸部安裝有供載 置前述集氫器的罩殼。 請求項2所所記載之發明係在請求項1之短弧型放電燈 中，前述罩殼係具有用以使氫氣在該罩殻內流通的開口。 請求項3所記載之發明係在請求項1之短弧型放電燈中 ，前述罩殻被形成爲線圏狀。 請求項4所記載之發明係在請求項1至請求項3中任一 201126568 項之短弧型放電燈中’那述中空容器係形成爲大致c子狀 ’被捲裝在前述軸部。 請求項5所記載之發明係在請求項4之短弧型放電燈中 ，當將前述軸部的直徑設爲D2(mm) '前述大致C字狀 的中空容器的內徑設爲D1 ( mm )時，滿足下述數式（1) 的關係： ζ) 數式（1 ) D 卜D2 > 0.005 ( mm )。 (發明之效果） 藉由本發明之短弧型放電燈，在電極的軸部附設用以 載置由將吸收氫的集氣器材料予以密閉，並且透過氫的中 空容器所構成的集氫器的罩殼，配置在該罩殼內的集氫器 未被固定在電極的軸部。因此，防止被密閉在中空容器內 的集氣器材料露出於發光管內，而防止集氣器材料與被封 Q 入在發光管內的發光物質起反應，因此在放電燈亮燈時被 放出至發光管內的氫會被集氣器材料確實吸收，而可防止 放電燈的照度安定度降低。 【實施方式】 使用第1圖〜第5圖’說明本案發明之第1實施形態。 第1圖係顯示本實施形態之揭示一部分之發光管內部 的短弧型放電燈1的構成的斜視圖。 如該圖所示’短弧型放電燈1係具備有：發光管n、 -9 - 201126568 及在其兩端接連的密封管部12人與123。在發光管11的內 部，陰極13的本體部13 A與陽極14的本體部14八彼此相向 配置，並且在放電空間S被封入有發光物質。至少封入水 銀作爲發光物質，封入氙、氬、氪之至少i種作爲緩衝氣 體。此外，亦可封入氙、氬、氪之至少丨種以上作爲發光 物質。陰極13係藉由軸部ι3Β及比其更爲大徑的本體部 13A所構成。在軸部13B，係在罩殻^內載置有在透過氫 的中空容器內密閉吸收氫的集氣器材料而成的集氫器。此 外’陽極1 4係藉由軸部1 4B及比其更爲大徑的本體部〗4 a 所構成。 第2圖係顯不將被固定在第1圖所示陰極13之軸部13B 周圍之在內部載置有集氫器23的罩殼I5的一部分作切口的 構成的斜視圖。 如該圖所示’在罩殻1 5內，例如由具有大致C字形狀 的中空容器16所構成的集氫器23被載置於未圖示的軸部 13B周圍。其中’安裝罩殼15的場所若爲電極部（本體部 與軸部）即可，並非限定於陰極側的軸部。 第3圖（a)係顯不將吸附氫的集氣器材料17予以密閉， 並且藉由使氫透過的金屬所構成的直管狀中空容器18的構 成的斜視圖，第3圖（b)係由第3圖（a)的A-A觀看的剖面圖 ，第3圖（c)係由第3圖（a)的B-B觀看的剖面圖。 如該等圖所示，兩端的密封部1 8 A、1 8B係藉由將構 成中空容器18的直管部18C的兩端進行壓接加工，或藉由 進行熔著或熔接，而予以氣密式密閉。藉此，將中空容器 -10" 201126568 1 8內的集氣器材料1 7與放電空間隔離，防止與放電空間內 的氣體直接接觸，並且使集氣器材料17不會漏洩至中空容 器18的外部。其中，中空容器18並不一定必須在其兩端形 成密封部，亦可形成爲例如使用有底筒狀的構件而僅將一 端側作密封的構造。 第2圖所示之具有大致C字形狀的中空容器16係藉由將 第3圖（b)所示之中空容器1 8的兩端朝紙面的上側或下側進 f) 行彎曲加工而形成爲C字形狀者。 第4圖係顯示在第1圖所示陰極13之軸部13B周圍，安 裝有載置有由將集氣器材料17予以密閉，並且透過氫的中 空容器16所構成的集氫器的罩殼15之構成的剖面圖。 如該圖所示，罩殻1 5係形成有用以以上下揷入電極軸 部1 3 B的開口 1 5 1 A、1 5 1 B的圓筒狀容器，藉由例如鎢、鉬 、钽等材料所構成。在罩殼15係使由被捲裝在軸部13B的 線圈狀線材所構成的一對防落構件1 9 A、1 9 B以上下包夾 Ο 罩殼15的方式作配置，而被固定在軸部13B。罩殼15係上 方側的開口 1 5 1 A的直徑大於軸部1 3 B的直徑，通過開口 151A而被放出至發光管η內的氫氣會被導引至罩殼15內 。由中空容器16所構成的集氫器23不會有被熔接在軸部 1 3 Β的情形，而在被捲裝在軸部】3 β周圍的狀態下被載置 於罩殼15內，藉由罩殻15的底板152防止落下。 此外，如第4圖所示，由釔等吸收氫的材料所構成的 集氣器材料17係被密封在由钽等使氫透過的金屬所構成的 大致C字狀的中空容器16內。中空容器16係由使氫透過’ -11 - 201126568 但難以與水銀起反應的金屬所構成，例如由鉅或鈮所構成 。鉬及鈮可爲單體，亦可爲與其他物質的化合物。藉由該 等物質所構成的中空容器1 6係效率佳地使氫透過，並且防 止集氣器材料17與尤其水銀等放電媒體起反應，而且可去 除發生在發光管11內的氫等不純氣體。集氣器材料17爲例 如釔或銷。釔或锆等物質的氫吸留力佳。釔及鉻可爲單體 ，亦可爲與其他物質的化合物。 接著，若針對軸部1 3 B的直徑與形成爲大致C字狀的 中空容器1 6的內徑的關係加以說明，當將軸部1 3 B的直徑 設爲D2(mm)，將大致C字狀的中空容器16的內徑設爲 D1 (mm)時，滿足以下數式（1)的關係。 數式（1) D 1-D2 > 0.005 ( mm ) 亦即，若軸部1 3 B的直徑D 2與中空容器1 6的內徑D 1滿 足上述數式（1)的關係時，係在軸部13B與中空容器16之 間介在有間隙。因此，藉由該間隙，在短弧型放電燈1亮 燈時，軸部1 3 B呈高溫化的情形下，阻礙熱由軸部1 3 B流 入至中空容器1 6。結果，抑制集氣器材料1 7高溫化，不會 有損及集氣器材料1 7之氫吸收功能的情形。 第5圖係顯示製作中空容器16的內徑D1與軸部13B的 直徑D2彼此不同之7種短弧型放電燈，將（D1-D2)與照 度變動率（照度安定度）的關係進行實驗後的結果的表。 在此，實驗所使用的短弧型放電燈係如以下規格者。 -12- 201126568 發光管內容積爲lxl(T3m3、氙封入量爲8xl04Pa、水銀封 入量爲35mg/ cc、電極間距離爲l=<l〇_2m、陰極側軸部外 徑爲約8mm。 此外，實驗所使用的集氫器23的相關規格如以下所示 。由內含將由作爲氫吸留物質之釔所構成的集氣器材料1 7 予以密封之大致C形狀的鉬中空容器16的罩殼15所構成， 作爲集氣器材料17之釔的量爲l.Og，鉅中空容器16的尺寸 () 係壁厚0.1 5 mm，大致C形狀的鉅中空容器1 6的內徑爲約 8mm，外徑爲13.5mm，高度爲12mm，罩殼15的尺寸係內 徑14mm、外徑16mm、內高度14mm、外高度16mm，材質· 係藉由Φ 1的純鎢而形成爲覆蓋形狀者。 如該表所示，中空容器16的內徑D1爲Φ7.950〜 Φ 8.3 05mm >軸部13B的直徑D2的直徑爲φ 7.945〜 Φ 8 _ 0 5 0 mm。 此外，藉由實驗所計算出的照度變動率（照度安定度 〇 )的計算方法如以下所示。首先，將短弧型放電燈安裝在 曝光裝置，在其光罩（遮罩）面設置照度計，接著在亮燈 至短弧型放電燈的照度成爲安定爲止之後，測定出一定時 間（例如在1秒鐘內測定1 〇〇點）期間的照度。將所測定出 的照度的最大値與最小値的差除以平均値，另外再乘上 1 〇〇，藉此計算出照度變動率（％ )。 如該表之實驗結果所示，可知當中空容器16的內徑 D1大於軸部13B的直徑D2時，即使該差値爲0.00 5，亦可 將變動率抑制爲較低。亦即，藉由未密接，集氣器材料i 7 -13- 201126568 的溫度下降，氫吸收量增加之故。其中，若中空容器16的 內徑D1小於軸部13B的直徑D2時的差値係設爲〇 〇5〇以下 。在D 1 - D 2爲負的情形下，藉由中空容器〗6所具有的彈性 而被安裝在軸部。若D1-D2的値大於〇.〇5〇，則在超過彈性 界限的軸部13B無法放入中空容器16之故。 藉由本實施形態之短弧型放電燈，由構成發光管11的 發光管構成構件被放出至發光管內的氫會流入至罩殼15內 ’透過集氫器23的中空容器16，藉由被密封在中空容器16 內的集氣器材料1 7所吸收，因此可防止照度安定度降低。 而且，集氫器23係中空容器I6不會被熔接在軸部13B而被 載置於罩殼15內，因此不會使集氣器材料17露出於發光管 內，而不會發生發光管11失透明、破裂等不良情形，可在 軸部13B周圍附設將集氣器材料17予以密閉的中空容器16 〇 使用第1圖及第6圖，說明本案發明之第2實施形態。 第ό圖係顯示在第1圖所示陰極13之軸部13B周圍，取 代罩殻1 5 ’而安裝有載置有由將集氣器材料〗7予以密閉， 並且透過氫的中空容器16所構成的集氫器23的罩殻20之構 成的剖面圖。 如第6圖所示’罩殼20係在上壁部201A、下壁部201B 的各個形成有開口 202A、202B，下壁部201B的開口 202B 的開口端被熔接在軸部13B，藉此被固定在軸部13B。被 設在上壁部201A的開口 202A的直徑，係以被放出在發光 管11內的氫可通過的方式，比軸部13B的直徑爲更大。由 -14* 201126568 密閉有集氣器材料17的中空容器16所構成的集氫器23係不 會有被熔接在軸部1 3 B的情形，而在被捲裝在軸部〗3 B周 圍的狀態下被載置於罩殼20內。被放出至發光管n內的氫 氣係通過罩殻20的上壁部201A的開口 202A而被導引至罩 殼20內’透過中空容器16而被集氣器材料17所吸收。 使用第1圖及第7圖’說明本案發明之第3實施形態。 第7圖係顯示在第1圖所示陰極13之軸部13B周圍，取 〇 代罩殻15 ’而安裝有載置有由將集氣器材料17予以密閉， 並且透過氫的中空容器16所構成的集氫器23的罩殼21之構 成的剖面圖。 如第7圖所示’罩殼21係藉由分別被設在上壁部211A 、下壁部211B的開口 212A、212B的開口端被熔接在軸部 i3B’而被固定在軸部13B。在下壁部211B係形成有用以 將被放出在發光管11內的氫氣導引至罩殻21內的環狀開口 213。由密閉有集氣器材料17的中空容器16所構成的集氫 〇 器23並不會有被熔接在軸部13B的情形，而在被捲裝在軸 部13B周圍的狀態下被載置於罩殼μ內。被放出在發光管 U內的氫氣係通過罩殼21的下壁部211B的開口 213而被導 引至罩殼21內’透過中空容器16，而被集氣器材料17吸收 〇 使用第1圖及第8圖’說明本案發明之第4實施形態。 第8圖（a)係顯不在第1圖所示陰極13之軸部13B周圍， 取代罩殼15 ’而安裝有載置有由將集氣器材料17予以密閉 ’並且透過氫的中空容器16所構成的集氫器23的罩殼22之 -15- 201126568 構成的斜視圖，第8圖（b )係揭示罩殻2 2之一部分的斜視圖 〇 如第8圖（a)、（b)所示，罩殼22係以包圍軸部13B的方 式將線材彼此稠密捲繞’藉此形成爲線圈狀，藉由將上端 部221A及下端部221B熔接在軸部13B而被固定在軸部13B 。在該罩殼22的內部，由密閉有集氣器材料17的中空容器 16所構成的集氫器23在被捲裝在軸部13B周圍的狀態下予 以載置。被放出在發光管11內的氫氣係通過構成罩殻22的 線材的間隙而被導引至罩殼22內，透過中空容器16，而被 集氣器材料17吸收。 使用第1圖及第9圖，說明本案發明之第5實施形態。 第9圖係在第1圖所示.陰極13之軸部13B周圍，各中空 容器與第3圖所示者相同，安裝有載置有由複數個直管狀 中空容器16(1)…16 (η)所構成的集氫器23的罩殼15的 構成，揭示罩殼1 5之一部分的斜視圖。 如第9圖所示，在第4圖所示之罩殼I5內，在軸部13Β 的周圍載置有由複數個直管狀中空容器16(1)〜16(η) 所構成的集氫器23。被放出至發光管11內的氫氣係通過罩 殼15的開口 151Α而被導引至罩殼15內，透過中空容器16 (1 )…1 6 ( η )，被各中空容器內的集氣器材料〗7所吸收 。其中，罩殼並非限定於第4圖所示之形狀的罩殼，亦可 使用第6圖〜第8圖所示之罩殼。 【圖式簡單說明】 -16- 201126568 第1圖係顯示第1實施形態之揭示一部分之發光管內部 的短弧型放電燈1的構成的斜視圖。 第2圖係揭示被固定在第1圖所示陰極13之軸部13B周 圍之在內部載置有集氫器23的罩殼15的一部分的斜視圖。 第3圖係顯示將吸附氫的集氣器材料1 7予以密閉，並 且藉由使氫透過的金屬所構成的直管狀中空容器18的構成 的斜視圖、由A - A觀看的剖面圖、及由B - B觀看的剖面圖 〇 。 第4圖係顯示在第1圖所示陰極13之軸部13B周圍，安 裝有載置有由將集氣器材料17予以密閉，並且透過氫的中 空容器16所構成的集氫器的罩殼15之構成的剖面圖。 第5圖係顯示將中空容器16的內徑D1與軸部13B的直 徑D2彼此不同之7種短弧型放電燈中的（D1-D2)與照度 變動率（照度安定度）的關係進行實驗後的結果的表。 第6圖係關於第2實施形態，在第1圖所示陰極13之軸 Q 部13B周圍，取代罩殼15，而安裝有載置有由將集氣器材 料17予以密閉，並且透過氫的中空容器16所構成的集氫器 23的罩殼20之構成的剖面圖。 第7圖係關於第3實施形態，在第1圖所示陰極13之軸 部13B周圍’取代罩殼15，而安裝有載置有由將集氣器材 料17予以密閉，並且透過氫的中空容器16所構成的集氫器 23的罩殼21之構成的剖面圖。 第8圖係關於第4實施形態，在第1圖所示陰極1 3之軸 部13B周圍，取代罩殼IS，而安裝有載置有由將集氣器材 -17- 201126568 料17予以密閉，並且透過氫的中空容器16所構成的集氫器 2 3的罩殼2 2之構成的斜視圖、及揭示罩殼2 2之一部分的斜 視圖。 第9圖係關於第5實施形態，在第1圖所示陰極1 3之軸 部13B周圍，安裝有載置有由複數個直管狀中空容器16(1 )…16 (η)所構成的集氫器23的罩殻15的構成，揭示覃 殼1 5之一部分的斜視圖。 第1 〇圖係顯示引用文獻2所記載之放電燈之槪略構成 及放電燈所具備之集氫器之剖面構造圖。 第1 1圖係專利文獻3所記載之陰極前端部的主要部位 正面剖面圖及俯視圖。 【主要元件符號說明】 I :短弧型放電燈 II :發光管 12Α、12Β :密封管部 13 :陰極 13Α :本體部 1 3 Β :軸部 14 :陽極 14Α :本體部 14Β :軸部 15 :罩殼 16 :中空容器 -18- 201126568 16 ( 1 )…16 ( η ):中空容器 1 7 :集氣器材料 18 :中空容器 1 8 A、1 8 B :密封部 1 8 C :直管部 19A、19B :防落構件 20 :罩殼 21 :罩殻 22 :罩殼 23 :集氫器 1 5 1 A、1 5 1 B :開口 152： 底板 20 1 A :上壁部 20 1 B :下壁部 202 A 、202Β ：開口 ) 21 ΙΑ :上壁部 2 1 1 Β :下壁部 2 1 2 A 、212Β :開口 2 13： 開口 22 1 A :上端部 22 1 Β :下端部 101 ： 燈泡 102、 103 :電極 104 ： 密封部 -19- 201126568 1 〇 5 :金屬箔 106 :集氫器 107 :石英棒 108 :石英筒 109 :集氫器材料 1 10 :有底圓筒 1 1 0Α :凸緣部 1 1 1 :蓋部 1 1 2 :金屬外皮 201 :電極 202 :圓錐狀部分 2 0 3 :細徑部 204 :線圈 205 :集氣器 d :直徑 S :放電空間 -20-BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a short arc type discharge lamp, and more particularly to a short arc type for a backlight source for use in an exposure light source or a projector for use in a semiconductor or liquid crystal manufacturing field. Discharge lamp. [Prior Art] The short arc type discharge lamp is close to a point light source because the front end distance of a pair of electrodes disposed in opposite directions in the arc tube is short, and thus it is used as an exposure device or a projector by combining with an optical system. The light source for backlight is used. Patent Document 1 discloses a short arc type discharge lamp of the prior art. According to this document, it has been pointed out that excimer light emission due to helium gas, helium gas and argon gas as buffer gas in helium gas and mercury vapor short arc lamp in a short arc lamp causes a discharge vessel in quartz glass. The inside of the inside produces a problem of white turbidity. In addition, according to the document, in the above-mentioned problem, it is described that the average OH group concentration in the range of 200 μm from the inner surface of the portion where the ultraviolet radiation divergence of the discharge vessel is maximized is 7.8 χ 1 . 0 24 / m3 or more, and the average sulfhydryl concentration in the range of 20 μm from the inner surface is 1.5 x 1 〇 25 / m 3 or more and 1 · 2 χ 1 06 6 / m 3 or less. However, as described above, the light-emitting tube contains an OH group which diffuses as Ηβ in the light-emitting space, and H20 diffused in the light-emitting tube is thermally decomposed into oxygen and hydrogen by heat from the arc. According to the results of -5-201126568, which was carefully studied by the inventors, it was found that the hydrogen generated in the arc tube as described above lowered the stability of the illuminance. The decrease in illuminance stability causes a change in the incident amount or incident angle distribution of light to the optical system due to arc sloshing. The period of the sway varies depending on the optical system, but a so-called flicker in which the illuminance variation greatly increases between several milliseconds and several seconds occurs. This reduction in illuminance stability causes a problem in the image projection device due to flickering of the screen, and the exposure device causes a problem of uneven exposure. Further, Patent Document 2 discloses a content in which a hydrogen collector for absorbing hydrogen discharged into an arc tube is disposed in an arc tube. Fig. 10(a) is a schematic structural view showing a discharge lamp described in the document, and Fig. 10(b) is a cross-sectional view showing a hydrogen collector provided in the discharge lamp shown in Fig. 1(a). Figure. The discharge lamp shown in Fig. 10(a) includes a bulb 1 〇1, electrodes 102 and 103, a sealing portion 104, and a metal foil 1〇5. 106 is a hydrogen collector, 107 is a quartz rod, and 108 is quartz. cylinder. The hydrogen collector 1〇6 is shown in Fig. 10(b), and the cylindrical hydrogen collector material 109 is sealed by a metal such as tantalum and includes a bottomed cylinder 110 and a lid. The inside of the metal sheath 112 of 111. The inside of the metal sheath 1 1 2 is sealed by the flange portion 1 1 0 A of the bottomed cylinder 110 and the lid portion 1 1 1 being resistively welded. The hydrogen collector 106 is attached to the bulb 101 as shown in Fig. 10(a), and the quartz cylinder 1〇8 containing the hydrogen collector 〇6 is fixed by the quartz rod 107 provided in the quartz cylinder 1〇8. The other end is welded to the bulb 1 〇1 and fixed to the bulb 1 〇1. The gas in the bulb 1 0 1 intrudes into the inside through the hydrogen-permeable bottomed cylinder 1 1 , and is adsorbed by the hydrogen collector material 109. The hydrogen collector material 109 is sealed inside the metal sheath 112 composed of the bottomed cylinder -6 - 201126568 110 and the cover portion 111, thereby preventing the hydrogen absorbing material 109 from reacting with other substances in the luminescent space. It can efficiently adsorb hydrogen. However, in the discharge lamp, since the hydrogen collector 106 is attached to the structure of the bulb 101, the hydrogen collector 106 reacts with the ruthenium oxide which is a constituent component of the bulb 101. Thereby, the bulb 1 0 1 loses transparency, resulting in a decrease in illuminance or a rupture of the bulb 101. Further, Patent Document 3 discloses a short arc discharge lamp in which an impurity gas adsorbing member is bonded to an electrode by welding or the like. Fig. 11 (a) and (b) are a front cross-sectional view and a plan view, respectively, of a main portion of a cathode tip end portion of the document, and the electrode 201 is formed in a parallel portion other than the conical portion 202, and has a diameter smaller than a diameter d. The small diameter portion is 2〇3. A cylindrical air collector 205 composed of a pin foil is disposed in a space between the small-diameter portion 203 and the coil 204, and is fixed to the small-diameter portion 203 ° by an appropriate means such as welding (Prior Art [Patent Document] [Patent Document 1] Japanese Patent No. 2891997 [Patent Document 2] Japanese Patent Publication No. Sho 57-21835 [Patent Document 3] Japanese Patent No. 3 3 0 0 6 1 5 [Invention] The subject of the present invention is directed to the metal sheath 112 of the argon collector material 109 shown in Fig. 10 when the hydrogen collector is disposed in the arc tube, as shown in Patent Document 3 The method of welding to the electrode and fixing it is reviewed. Although the method is found to be extremely effective for the loss of transparency and cracking of the above-mentioned bulb, when the metal sheath is welded to the electrode, it is predicted that the hole will be vacated in the metal sheath during the welding to expose the hydrogen collector material to the arc tube. The hydrogen hydride material reacts with a luminescent substance such as mercury enclosed in the arc tube to lower the hydrogen absorbing function of the hydrogen concentrator material. In view of the above problems, an object of the present invention is to provide a short arc type discharge lamp in which an electrode in an arc tube is provided with a short arc type discharge lamp in which a hydrogen absorbing hydrogen collector is sealed and a hydrogen container is permeable to hydrogen. The hydrogen collector is not fixed to the electrode and is provided. (Means for Solving the Problems) In order to solve the above problems, the invention described in claim 1 is characterized in that a short arc type discharge lamp is formed in an arc tube and is composed of a main body portion and a shaft portion connected to the main body portion. A pair of electrodes are disposed to face each other, and a hydrogen collector in which a hydrogen absorbing collector material is sealed in a hollow container that transmits hydrogen is provided. The short arc type discharge lamp is characterized in that the shaft portion is mounted for mounting. The cover of the aforementioned hydrogen collector. The invention of claim 2 is the short arc type discharge lamp of claim 1, wherein the casing has an opening for allowing hydrogen gas to flow through the casing. The invention of claim 3 is the short arc type discharge lamp of claim 1, wherein the casing is formed in a coil shape. According to the invention of claim 4, in the short arc type discharge lamp of any of claims 1 to 3, the hollow container is formed in a substantially c-shaped shape and is wound around the shaft portion. According to the invention of claim 5, in the short arc type discharge lamp of claim 4, the diameter of the shaft portion is D2 (mm). The inner diameter of the substantially C-shaped hollow container is D1 (mm). When the relationship of the following formula (1) is satisfied: ζ) Equation (1) D Bu D2 > 0.005 ( mm ). (Effect of the Invention) According to the short arc type discharge lamp of the present invention, a hydrogen collector for arranging a hydrogen container in which a collector material for absorbing hydrogen is sealed and hydrogen is permeated is attached to a shaft portion of the electrode. The casing, the hydrogen collector disposed in the casing is not fixed to the shaft portion of the electrode. Therefore, the trap material sealed in the hollow container is prevented from being exposed in the arc tube, and the collector material is prevented from reacting with the luminescent material sealed in the arc tube, and thus is discharged when the discharge lamp is turned on. The hydrogen in the arc tube is surely absorbed by the collector material, and the illuminance stability of the discharge lamp is prevented from being lowered. [Embodiment] A first embodiment of the present invention will be described with reference to Figs. 1 to 5 . Fig. 1 is a perspective view showing the configuration of a short arc type discharge lamp 1 inside a light-emitting tube which is a part of the embodiment. As shown in the figure, the short-arc type discharge lamp 1 is provided with an arc tube n, -9 - 201126568, and a sealed tube portion 12 and 123 connected at both ends thereof. In the inner portion of the arc tube 11, the main body portion 13A of the cathode 13 and the main body portion 14 of the anode 14 are disposed to face each other, and a luminescent substance is sealed in the discharge space S. At least mercury is enclosed as a luminescent material, and at least one of helium, argon, and krypton is enclosed as a buffer gas. Further, at least one of neon, argon or xenon may be enclosed as a luminescent substance. The cathode 13 is constituted by a shaft portion ι3 Β and a body portion 13A having a larger diameter than the cathode portion 13A. In the shaft portion 13B, a hydrogen collector in which a collector material for absorbing hydrogen is sealed in a hollow container through which hydrogen is passed is placed in the casing. Further, the anode 14 is composed of a shaft portion 14B and a main body portion 4a having a larger diameter. Fig. 2 is a perspective view showing a configuration in which a part of the casing I5 in which the hydrogen collector 23 is placed is not fixed around the shaft portion 13B of the cathode 13 shown in Fig. 1 . As shown in the figure, in the casing 15, for example, a hydrogen collector 23 composed of a hollow container 16 having a substantially C-shape is placed around a shaft portion 13B (not shown). The place where the cover 15 is attached may be an electrode portion (a main body portion and a shaft portion), and is not limited to the shaft portion on the cathode side. Fig. 3(a) is a perspective view showing a configuration of a straight tubular hollow container 18 which is formed by sealing a hydrogen-absorbing gas collector material 17 and a metal which transmits hydrogen, and Fig. 3(b) A cross-sectional view taken from AA of Fig. 3(a), and Fig. 3(c) is a cross-sectional view taken along line BB of Fig. 3(a). As shown in the figures, the seal portions 18A, 18B at both ends are crimped by crimping both ends of the straight tube portion 18C constituting the hollow container 18, or by fusing or welding. Closed airtight. Thereby, the collector material 17 in the hollow container-10" 201126568 18 is isolated from the discharge space, preventing direct contact with the gas in the discharge space, and preventing the collector material 17 from leaking to the hollow container 18. external. Here, the hollow container 18 does not necessarily have to have a seal portion formed at both ends thereof, and may be formed, for example, by using a member having a bottomed cylindrical shape and sealing only one end side. The hollow container 16 having a substantially C-shape shown in Fig. 2 is formed by bending both ends of the hollow container 18 shown in Fig. 3(b) toward the upper side or the lower side of the paper surface. For the C shape. Fig. 4 is a view showing a casing of a hydrogen collector in which a hollow vessel 16 for sealing the separator material 17 and permeating hydrogen is placed around the shaft portion 13B of the cathode 13 shown in Fig. 1. A cross-sectional view of the composition of 15. As shown in the figure, the casing 15 is formed into a cylindrical container having openings 1 5 1 A and 1 5 1 B which are inserted into the electrode shaft portion 1 3 B from above, by, for example, tungsten, molybdenum, niobium, or the like. Made up of materials. The cover 15 is disposed such that the pair of fall prevention members 1 9 A and 1 9 B composed of the coil-shaped wires wound around the shaft portion 13B are placed so as to sandwich the cover case 15 and are fixed to Shaft portion 13B. The opening of the upper side of the casing 15 is larger than the diameter of the shaft portion 13B, and the hydrogen gas which is discharged into the arc tube n through the opening 151A is guided into the casing 15. The hydrogen collector 23 composed of the hollow container 16 is not welded to the shaft portion 13 3 , but is placed in the casing 15 while being wound around the shaft portion 3 β. Falling is prevented by the bottom plate 152 of the casing 15. Further, as shown in Fig. 4, the collector material 17 composed of a material that absorbs hydrogen or the like is sealed in a substantially C-shaped hollow container 16 made of a metal that transmits hydrogen such as helium. The hollow container 16 is made of a metal that allows hydrogen to permeate -11 - 201126568 but is difficult to react with mercury, and is composed of, for example, giant or strontium. Molybdenum and rhenium may be monomers or compounds with other substances. The hollow container 16 made of these substances efficiently transmits hydrogen, and prevents the collector material 17 from reacting with a discharge medium such as mercury, and removes impurities such as hydrogen generated in the arc tube 11. . The collector material 17 is, for example, a crucible or a pin. Materials such as cerium or zirconium have good hydrogen occlusion. Niobium and chromium may be monomers or compounds with other substances. Next, the relationship between the diameter of the shaft portion 1 3 B and the inner diameter of the hollow container 16 formed in a substantially C shape will be described. When the diameter of the shaft portion 13 B is D2 (mm), substantially C When the inner diameter of the hollow container 16 is D1 (mm), the relationship of the following formula (1) is satisfied. The equation (1) D 1-D2 > 0.005 ( mm ), that is, when the diameter D 2 of the shaft portion 13 B and the inner diameter D 1 of the hollow container 16 satisfy the relationship of the above formula (1), There is a gap between the shaft portion 13B and the hollow container 16. Therefore, when the short-arc discharge lamp 1 is turned on by the gap, when the shaft portion 13B is heated, the heat is prevented from flowing from the shaft portion 13b to the hollow container 16. As a result, the high temperature of the collector material 17 is suppressed, and the hydrogen absorption function of the collector material 17 is not impaired. Fig. 5 is a view showing seven types of short arc type discharge lamps in which the inner diameter D1 of the hollow container 16 and the diameter D2 of the shaft portion 13B are different from each other, and the relationship between the (D1-D2) and the illuminance variation rate (illuminance stability) is experimentally performed. After the results of the table. Here, the short arc type discharge lamp used in the experiment is as follows. -12- 201126568 The inner volume of the luminous tube is lxl (T3m3, the encapsulation amount is 8xl04Pa, the mercury encapsulation amount is 35mg/cc, the interelectrode distance is l=<l〇_2m, and the cathode side shaft outer diameter is about 8mm. Further, the relevant specifications of the hydrogen collector 23 used in the experiment are as follows. The substantially C-shaped molybdenum hollow container 16 containing the collector material 17 composed of the crucible as the hydrogen storage material is sealed. The cover 15 is constructed such that the amount of the collector material 17 is 1.0 g, the size of the giant hollow container 16 is 0.15 mm, and the inner diameter of the substantially C-shaped hollow container 16 is about 8mm, outer diameter is 13.5mm, height is 12mm, and the size of the casing 15 is 14mm inner diameter, outer diameter 16mm, inner height 14mm, outer height 16mm, and the material is formed by covering pure shape with Φ 1 pure tungsten. As shown in the table, the inner diameter D1 of the hollow container 16 is Φ7.950 to Φ 8.3 05 mm > the diameter of the diameter D2 of the shaft portion 13B is φ 7.945 to Φ 8 _ 0 5 0 mm. The calculation method of the calculated illuminance variation rate (illuminance stability 〇) is as follows. First, the short arc type discharge lamp is installed at In the optical device, an illuminometer is placed on the mask (mask) surface, and then after the illumination of the short-arc discharge lamp is stabilized, the measurement is performed for a certain period of time (for example, 1 测定 in 1 second) The illuminance of the period. The illuminance variation rate (%) is calculated by dividing the difference between the maximum 値 and the minimum 照 of the measured illuminance by the average 値, and multiplying by 1 。. It can be seen that when the inner diameter D1 of the hollow container 16 is larger than the diameter D2 of the shaft portion 13B, even if the difference is 0.005, the variation rate can be suppressed to be low. That is, the collector material i is not closely adhered. When the temperature of 7-13-201126568 is lowered, the amount of hydrogen absorption is increased. When the inner diameter D1 of the hollow container 16 is smaller than the diameter D2 of the shaft portion 13B, the difference is 〇〇5〇 or less. When D 2 is negative, it is attached to the shaft portion by the elasticity of the hollow container 6. If the 値 of D1-D2 is larger than 〇.〇5〇, the shaft portion 13B exceeding the elastic limit cannot be placed. The hollow container 16 is formed by the short arc type discharge lamp of the present embodiment. The hydrogen which is discharged from the light-emitting tube constituent member into the arc tube flows into the hollow container 16 of the housing 15 which is transmitted through the hydrogen collector 23, and is absorbed by the collector material 17 sealed in the hollow container 16. Therefore, the illuminance stability can be prevented from being lowered. Further, the hydrogen concentrator 23 is not fused to the shaft portion 13B and is placed in the casing 15 so that the concentrator material 17 is not exposed to the illuminating tube. In the case where the arc tube 11 is not transparent or broken, a hollow container 16 for sealing the air collector material 17 may be attached around the shaft portion 13B. The first and sixth figures are used to explain the present invention. The second embodiment. In the second diagram, around the shaft portion 13B of the cathode 13 shown in Fig. 1, a hollow container 16 in which the collector material 7 is sealed and hydrogen is permeated is mounted instead of the casing 15'. A cross-sectional view of the configuration of the casing 20 of the hydrogen collector 23 constructed. As shown in Fig. 6, the cover 20 is formed with openings 202A and 202B in each of the upper wall portion 201A and the lower wall portion 201B, and the open end of the opening 202B of the lower wall portion 201B is welded to the shaft portion 13B. It is fixed to the shaft portion 13B. The diameter of the opening 202A provided in the upper wall portion 201A is larger than the diameter of the shaft portion 13B so that the hydrogen discharged into the arc tube 11 can pass. The hydrogen collector 23 composed of the hollow container 16 in which the collector material 17 is sealed by -14* 201126568 is not welded to the shaft portion 13 3 B, but is wrapped around the shaft portion 〖3 B In the state of being placed in the casing 20. The hydrogen gas discharged into the arc tube n is guided into the casing 20 through the opening 202A of the upper wall portion 201A of the casing 20, and is absorbed by the collector material 17 through the hollow container 16. A third embodiment of the present invention will be described using Figs. 1 and 7'. Fig. 7 is a view showing a hollow container 16 in which a gas container material 17 is sealed and a hydrogen gas is placed around a shaft portion 13B of the cathode 13 shown in Fig. 1 . A cross-sectional view showing the configuration of the casing 21 of the hydrogen collector 23. As shown in Fig. 7, the casing 21 is fixed to the shaft portion 13B by being welded to the shaft portion i3B' at the opening ends of the openings 212A and 212B provided in the upper wall portion 211A and the lower wall portion 211B, respectively. An annular opening 213 for guiding the hydrogen gas discharged into the arc tube 11 into the casing 21 is formed in the lower wall portion 211B. The hydrogen collecting damper 23 composed of the hollow container 16 in which the erector material 17 is sealed is not welded to the shaft portion 13B, but is placed in a state of being wound around the shaft portion 13B. Inside the cover μ. The hydrogen gas discharged into the arc tube U is guided to the inside of the casing 21 through the opening 213 of the lower wall portion 211B of the casing 21, and is absorbed by the air trap material 17, and is used in the first drawing. And Fig. 8' illustrates a fourth embodiment of the invention of the present invention. Fig. 8(a) shows the periphery of the shaft portion 13B of the cathode 13 shown in Fig. 1, and a hollow container 16 on which the collector material 17 is sealed and hydrogen is placed is mounted instead of the casing 15'. An oblique view of the casing 22 of the hydrogen collector 23 is constructed as -15-201126568, and FIG. 8(b) is a perspective view showing a part of the casing 22, as shown in Figs. 8(a) and (b). As shown in the figure, the casing 22 is densely wound around the shaft portion 13B so as to be formed in a coil shape, and is fixed to the shaft portion 13B by welding the upper end portion 221A and the lower end portion 221B to the shaft portion 13B. . In the inside of the casing 22, the hydrogen collector 23 composed of the hollow container 16 in which the collector material 17 is sealed is placed in a state of being wound around the shaft portion 13B. The hydrogen gas discharged into the arc tube 11 is guided into the casing 22 through the gap of the wire constituting the casing 22, passes through the hollow vessel 16, and is absorbed by the collector material 17. A fifth embodiment of the present invention will be described with reference to Figs. 1 and 9. Fig. 9 is a view showing the vicinity of the shaft portion 13B of the cathode 13 in Fig. 1. The hollow containers are mounted in the same manner as in Fig. 3, and are mounted with a plurality of straight tubular hollow containers 16(1)...16 ( The configuration of the casing 15 of the hydrogen collector 23 constituted by η) is a perspective view showing a part of the casing 15. As shown in Fig. 9, in the casing I5 shown in Fig. 4, a hydrogen collecting device composed of a plurality of straight tubular hollow containers 16(1) to 16(n) is placed around the shaft portion 13A. twenty three. The hydrogen gas discharged into the arc tube 11 is guided into the casing 15 through the opening 151 of the casing 15, passes through the hollow containers 16(1)...16(n), and is collected by the gas collectors in the hollow containers. Material 〗 7 absorbed. Here, the casing is not limited to the casing of the shape shown in Fig. 4, and the casings shown in Figs. 6 to 8 may be used. [Brief Description of the Drawings] -16- 201126568 Fig. 1 is a perspective view showing the configuration of the short arc type discharge lamp 1 inside the arc tube which is a part of the disclosure of the first embodiment. Fig. 2 is a perspective view showing a part of the casing 15 which is fixed to the shaft portion 13B of the cathode 13 shown in Fig. 1 and in which the hydrogen collector 23 is placed. Fig. 3 is a perspective view showing a configuration of a straight tubular hollow container 18 in which a hydrogen absorbing collector material 17 is sealed and a metal through which hydrogen is permeated, a cross-sectional view taken from A - A, and A section view taken by B-B. Fig. 4 is a view showing a casing of a hydrogen collector in which a hollow vessel 16 for sealing the separator material 17 and permeating hydrogen is placed around the shaft portion 13B of the cathode 13 shown in Fig. 1. A cross-sectional view of the composition of 15. Fig. 5 shows an experiment in which the relationship between the (D1-D2) and the illuminance variation rate (illuminance stability) of seven kinds of short arc type discharge lamps in which the inner diameter D1 of the hollow container 16 and the diameter D2 of the shaft portion 13B are different from each other is shown. After the results of the table. Fig. 6 is a view showing a second embodiment, in which the casing 9 is placed around the shaft Q portion 13B of the cathode 13 shown in Fig. 1, and the collector material 17 is sealed and hydrogen is permeated. A cross-sectional view showing the configuration of the casing 20 of the hydrogen collector 23 constituted by the hollow container 16. In the third embodiment, the cover 15 is replaced by the cover 15 around the shaft portion 13B of the cathode 13 shown in Fig. 1, and a hollow is provided in which the collector material 17 is sealed and hydrogen is permeated. A cross-sectional view showing the configuration of the casing 21 of the hydrogen collector 23 constituted by the container 16. Fig. 8 is a view showing a fourth embodiment in which the gas collection device -17-201126568 material 17 is sealed around the shaft portion 13B of the cathode 13 shown in Fig. 1, instead of the casing IS. Further, a perspective view of the configuration of the casing 2 2 of the hydrogen collector 2 3 which is formed by the hollow container 16 through which hydrogen is passed, and a perspective view showing a part of the casing 2 2 are disclosed. Fig. 9 is a view showing a fifth embodiment in which a set of a plurality of straight tubular hollow containers 16(1) ... 16 (η) is mounted around the shaft portion 13B of the cathode 13 shown in Fig. 1 . The configuration of the casing 15 of the hydrogenator 23 reveals a perspective view of a portion of the clamshell 15. Fig. 1 is a cross-sectional structural view showing a schematic configuration of a discharge lamp described in Reference 2 and a hydrogen collector provided in the discharge lamp. Fig. 1 is a front cross-sectional view and a plan view of a main portion of a cathode tip end portion described in Patent Document 3. [Description of main component symbols] I: Short arc discharge lamp II: Illumination tube 12Α, 12Β: Sealed tube part 13: Cathode 13Α: Main body part 1 3 Β : Shaft part 14: Anode 14Α: Main body part 14Β: Shaft part 15: Cover 16: Hollow container-18- 201126568 16 ( 1 )...16 ( η ): Hollow container 1 7 : Collector material 18 : Hollow container 1 8 A, 1 8 B : Sealing part 1 8 C : Straight pipe part 19A, 19B: fall prevention member 20: cover 21: cover 22: cover 23: hydrogen collector 1 5 1 A, 1 5 1 B: opening 152: bottom plate 20 1 A: upper wall portion 20 1 B : lower Wall portion 202 A , 202 Β : opening) 21 ΙΑ : upper wall portion 2 1 1 Β : lower wall portion 2 1 2 A , 212 Β : opening 2 13 : opening 22 1 A : upper end portion 22 1 Β : lower end portion 101 : bulb 102, 103: Electrode 104: Sealing portion-19-201126568 1 〇5: Metal foil 106: Hydrogen collector 107: Quartz rod 108: Quartz cylinder 109: Hydrogen collector material 1 10: Bottom cylinder 1 1 0Α: convex Edge portion 1 1 1 : cover portion 1 1 2 : metal sheath 201 : electrode 202 : conical portion 2 0 3 : small diameter portion 204 : coil 205 : gas collector d : diameter S : discharge space -20 -