200845100 九、發明說明： L發明戶斤屬之技術領域】 發明領域 本發明係有關於一種照射紫外線之短弧型等之放電燈 5 用之電極結構，特別是有關於一種電極之溫度上升少之放 電燈的電極結構。 L先前技術】 發明背景 一般而言，以往在形成半導體之配線圖案時，係使用 10 照射紫外線之短弧型放電燈等作為光源。前述放電燈係透 過電極棒並藉由石英製之密封管將陽極固持於放電空間 内，並在以陽極為上或下之狀態下垂直點燈以進行使用。 因此，放電燈在點燈時便成為高溫狀態係眾所周知的。又， 當放電燈呈點燈狀態時，陽極會與從陰極送來之電子衝 15 突，並因該衝突產生蒸發、消耗。再者，當電極因電子之 衝突而消耗時，放電燈之内壁，特別是從發光管中央部至 上部侧的内管壁會因熱對流而黑化。再者，隨著近年高照 明度化之要求，放電燈亦大電力化，而陽極也大型化。由 於前述大型陽極非常重，因此由支撐電極之電極棒及石英 20 製之密封管等所構成之密封構造便會因放電燈之移動等衝 擊而有破損的情況。對於前述問題，則有將洞或槽設於陽 極以減輕重量，並調整燈泡内氣體的對流等方法，以進行 陽極之放熱及黑化防止。以下，舉出幾個與其相關之習知 技術之例。 5 200845100 專利文獻1所揭示之「短弧型放電燈」係改變放電燈内 之黑化位置之使用壽命長的燈。如第6(a)圖所示，該燈形成 有從陽極前端側延伸至後端側之貫穿孔。當在陽極位於陰 極之上方的狀態下點燈時，燈泡内之氣體便因對流而流過 5陽極之貫穿孔内，因此可有效率地冷卻陽極。由於流過貫 穿孔之氣體會流至陽極後方，因此蒸發之陽極構成物質會 固化於密封部側端部，故燈泡之中央部不易黑化且使用壽 命變長。 專利文獻2所揭示之「短弧型放電燈」係改變放電燈内 1〇氣流之方向以改善燈泡之透光率之使用壽命長的燈。如第 6(b)圖所示，該㈣將突起與環狀槽設於陽極之轉部之周 圍後端部。首先，叫氣流並使其沿著突起與環狀槽循環， 而使条發物附著於環狀槽、電極棒與燈泡管壁。藉此，燈 泡中央領域之有效利用範圍之蒸發物附著量便顯著的減 15少。由於可維持高照明度，因此使用壽命變長。 專利文獻3所揭示之「放電燈用陽電極」係、防止前端部 溶化與*發之防止變形的陽極。如第6(e)圖所示，該陽極係 將空洞設於陽極内部，並將氣體流入孔設於前端部，並且 將壓力e周整孔设於後端部或側面部。藉此，從氣體流入孔 20將口弧放私而產生之高溫高速氣體吸入空洞，並從陽極之 内壁將熱月b釋放至外部。由於可利用空洞進行散熱，因此 可有效地分散熱能。 【專利文獻丨】特開平1〇·2〇8696號公報 文獻2】特開2006-012672號公報 200845100 【專利文獻3】特開2006-221934號公報 【考务明内容^】 發明揭示 發明欲解決之問題 5 然而，習知之放電燈的電極具有以下問題。當將貫穿 孔設於陽極之前端側時，燈泡内之氣體便流過貫穿孔内， 而電弧便產生搖晃。當貫穿孔附近產生異常放電時，電極 便明顯地消耗。當將突起設於雜之後料，陽極便變重。 卩使單純地加殊陽極後端部之槽，氣流亦不會產生特 1〇別的變化。若為炼接有蓋部分並設有空洞之陽極的話，溶 接部之加工與品質管理便變得複雜。若為於侧面部設有供 氣體机出之孔的陽極的話，蒸發的電極材料便會被吹到燈 泡之中央部，使得燈泡之有效利用領域之黑化變明顯。 本發明之目的在於解決前述問題，並使放電燈之電極 15成為放熱性與放電穩定性佳，輕量且不會破壞内部導棒及 密封管，並且容易製作且不易黑化之長壽命者。 解決問題之手段 為了解決前述問題，在本發明中，放電燈之電極之與 内。卩棒連接之連接部周圍形成有深度大於孔徑之凹部， 20而該放電燈包含有··發光管；一對於發光管内相對之圓柱 狀電極；及將電極固持於發光管内之内部導棒。又，本發 明形成有從電極之側面側開口部貫穿至凹部側開口部之貫 穿孔’且側面側開口部較凹部側開口部更靠近電極之放電 部側。又，當以電極之圓柱高度為Ll，並以凹部之深度為 200845100 h時，則（1^/3)<^<(21^/3)。當以電極之外徑為D，立 之内部導棒的最大外徑為A，並以凹部之最及、 士 為D3時， 則（(Uxpi - D2))<D3<(1 · 1 x(D厂 D2)) 〇 發明效果 5 11由前述結構，砂可利關柱狀電極之後__ 部將電極前端部附近之熱釋放至内部導棒側，因此可使帝 極輕量化，且可提高散熱效果，並可延長放電燈 命。藉由貫穿孔更可提升散熱效果。 可 C實施方式】 10 實施發明之最佳型態 以下，-面參照第1圖〜第5圖-面針對實施本發明之最 佳型態進行詳細的說明。 實施例1 本發明實施例1係一種放電燈，其係使用由放電點反對 15側之内部導棒固持，且於背面具有深凹部之陽極者。 第1圖係本發明實施例1之放電燈的外觀圖。第2圖係於 背面具有凹部之陽極的放大圖。第2(A)圖係陽極之外觀 圖。第2(B)圖係第2(A)圖之B-B截面圖。在第i圖與第2圖 中，放電燈1係於内部電極間進行放電之燈。陽極1〇係正側 20之電極。陰極9係負側之電極。内部導棒7係支撐電極並供 電之構件。密封管部3係將燈泡氣密密封之部分。外部導棒 5係從燈座透過金屬箔供電至電極之構件。發光部2係透過 電極間之放電而發光之部分，並是密封電極以形成放電空 間之玻璃構件。燈座4係機械性地固持燈並用以供電之構 200845100 件。凹部21係從背面朝向前端面設置之圓柱狀的洞。在此 係β兒明將凹部21設於陽極1〇之例，但亦可適用於陰極$。 接著，說明具有前述結構之本發明實施例丨之放電燈的 力月動作。首先，一面參照第1圖一面說明放電燈之功能 5概要。放電燈1之結構包含有：發光部2、2個密封管部3、 對向配置於發光部2中之陽極1〇及陰極9、支撐陽極⑺與陰 極9並進行通電之内部導棒7、外部導棒5、及利用導電性之 金屬箔6連接前述内部導棒7與外部導棒5並進行氣密地资 封之密封管部3。再者，密封管部3固定有燈座4,且另一密 10封官部3亦固定有燈座4。放電燈1係透過燈座4固定於光源 裝置。又，陽極10之背面（密封管部側之圓柱底面）設有凹部 21。 口 在本實施例中，係利用内部導棒7將一對圓柱狀電極固 持成在發光管内相對。又，陽極1〇之與内部導棒7連接之連 15接部周圍形成有較孔徑深之凹部。本實施例係藉由圓柱狀 陽極10之後端面的凹部21將陽極1〇前端部附近的熱釋放至 内部導棒7側。又，當以陽極1〇之圓柱高度為“，並以凹部 21之深度為&時，則（Ll/3)<L2<(2Li/3)。當以陽極1〇之外徑 為〇〗，凹部21内之内部導棒7的最大外徑為並以凹部幻 20 之最大徑為 時，則（〇.7x(Dl —D2))<D3<(Ux(Di_D2)) 〇 接著，一面參照第2圖一面說明陽極之功能。前端部11 係陽極10之圓柱狀部分，並由内部導棒7所固持。散熱部以 係連設於前端則之部分，且係於内部具有凹部21之陽極 10的圓筒狀部分。前端面14係圓柱狀電極之上面，並係於 200845100 陰極9之間進行放電之面。軀體面13係電極之圓柱側面。背 面Π係陽極10之圓柱底面。凹部21係設置成從背面朝向前 端面之圓柱狀的孔。凹部侧面22係圓柱狀凹部21之圓周上 的内側面。凹部底面23係圓柱狀凹部21之底面。電極固持 5 孔18係設於凹部底面23之孔。電極全長係陽極1〇之圓柱 軸方向的長度。凹部深度L2係從背面π至凹部底面23之圓 柱軸方向的長度。外徑Di係陽極之軀體面13的外徑。外徑 〇2係内部導棒7之外徑。外徑係凹部21之圓周側面的内 徑0 10 15 20 陽極ίο呈略圓柱狀，並由前端面14、前端側錐面15、 軀體面13、背面侧錐面16、背面17、及凹部幻所構成。凹 部21係由凹部側面22及凹部底面Μ所構成。藉由將内部導 棒7欲入設於凹部底面23之電極固持孔18，可將陽極刪持 於放電空間。當D#D3的差過小時，散熱㈣便會變薄， 因此陽極1()有可能因點亮燈時之熱或製造燈時之㈣而變 形。當D4D2的差過小時，凹部21之容積便會變小，因此 陽極H)之輕量化及釋放出電_部之熱的效果亦會變小。 紅舰2之差過小時，凹部底面23與前端_便會太過靠 近卩底面23與前端面1相近4時，電極固持孔18之底 面亦菅罪近前端面，因此無法加深電極固持孔Μ。當錢 加深電_持孔18時，電_持孔1咖部導棒7之欲合便 胃㈣m㈣導棒7脫落。特別地，當使燈 ，陽極職因電極之熱膨脹、收縮而更容易脫 洛0 10 200845100 當以陽極ίο之圓柱高度為Ll，並以凹部21之深度為L 時，則(WWPW3)為較適當。t以陽極1〇之身區幹部之 最小外徑為Di，配設於凹部21内之内部導棒7的最大外徑為 D2，並以凹部21之袁大徑為d3時，則（〇.7x(Di — 5 (1.lx(Dl 一 〇2))為較適當。藉由滿足前述條件，可提高陽極 10之冷卻效果，並可防止陽極10之變形，並且可防止陽極 10因熱而脫落。又，藉由使陽極10輕量化，可防止内部導 棒7之彎折及密封管之破損。因此，可延長燈之壽命。再者， 藉由將細微之槽設於散熱部12之表面，而可擴大散熱部12 10 之截面積，並可擴大散熱部12之散熱效果。 如前所述，在本發明之實施例1中，由於放電燈之結構 係使用由放笔點反對侧之内部導棒固持，並於背面具有深 凹部之％極’因此可利用圓柱狀電極之後端面的凹部將電 極前端部附近之熱放出至内部導棒側，故可使電極輕量 15化，且可提高散熱效果，並可延長放電燈之使用壽命。 實施例2 本發明實施例2係一種放電燈，其係使用背面具有凹 部，並形成有從軀體面貫穿至凹部内部之貫穿孔的電極者。 第3圖係本發明實施例2之放電燈之陽極的放大圖。第 20 3(A)圖係陽極之外觀圖。第3(B)圖係第3(A)圖之B-B截面 圖。在第3(A)及(B)圖中，陽極20係具有從軀體面貫穿至凹 部内部之貫穿孔之正側電極。貫穿孔24係連接軀體面13與 凹部21之孔。内部口 35係貫穿孔24之凹部側面側的開口部 分。外部口 36係貫穿孔24之軀體面侧的開口部分。如第 11 200845100 3(A)、（B)圖所示，陽極20之散熱部12設有連接軀體面13與 凹部21之貫穿孔24。貫穿孔24係均等地設置4個於電極之散 熱部12的圓周方向。 藉由將貝牙孔24設於散熱部12 ’可提南在點燈時成為 5高溫之陽極2〇之凹部21内的冷卻效果。再者，由於將貫穿 凹部21之貫穿孔24的外部口 26設於軀體面13上，因此放電 不會因流入貫穿孔24之對流而不穩定，貫穿孔24之外口部 26附近亦不會產生異常的電極消耗。故，可延長燈之壽命。 在此係說明圓周狀地設置4個貫穿孔之例，但並不限於 10 4個，亦可為6個孔。由於散熱部12之截面積變小，因此冷 卻前端部11之效果有可能因從陽極2〇之前端部丨丨至散熱部 12之熱傳達變小而降低。故，必須適當地設定貫穿孔μ之 直徑及數量。 實施例3 15 本發明實施例3係一種放電燈，其係使用背面具有凹 部，並具有從軀體面貫穿至凹部内部且朝電極前端面側傾 斜之貫穿孔之的電極者。 第4圖係本發明實施例3之放電燈之陽極的放大圖。第 4(A)圖係陽極之外觀圖。第4(B)圖係第4(A)圖之B_B戴面 20圖。在第4(A)及(B)圖中，陽極30係具有朝電極前端面側傾 斜之孔的正側電極。傾斜貫穿孔34係連接軀體面13與凹部 21之孔，並朝前端面14側傾斜。内部口 35係傾斜貫穿孔％ 之凹部側面22側的開口部分。外部口36係傾斜貫穿孔“之 軀體面13側的開口部分，並較内部口 35更靠近前端面 12 200845100 側。L3係内部口 35與外部口 36間的距離，並是電極之車由方 向的長度。如第4(A)及(B)圖所示，傾斜貫穿孔料係外口部 36較内口部35更朝前端面14側傾斜，並從散熱部12進入前 端部11側。 5 藉由傾斜貫穿孔34朝前端面14側傾斜，陽極3〇前端部 11之熱可有效率地放射。當使凹部底面23#近陽極3〇之前 端面14時，陽極30與内部導棒7之嵌合有可能會變得不充 分，但當傾斜貫穿孔34實際地靠近前端面14時，可提高前 端部11之冷卻效果。由於陽極3〇之前端部丨丨的冷卻效果 10高，因此可防止陽極30之變形，並可防止陽極3〇因熱而脫 落。 再者，由於將貫穿凹部21之傾斜貫穿孔34之外部口允 設於軀體面13上，因此放電不會因流入傾斜貫穿孔％之對 流而不穩定，傾斜貫穿孔34之外口部36附近亦不會產生異 15 常的電極消耗。故，可延長燈之壽命。 然而，由於有可能發生陽極30之變形、放電不穩定及 陽極30之異常的消耗，因此必須適當地設置其位置，使傾 斜貫穿孔34之外口部36不會太靠近前端面14。 實施例4 20 本發明實施例4係一種放電燈，其係使用背面具有凹 部’並具有從軀體面貫穿至凹部内部且朝電極前端面側傾 斜之貫穿孔，並且具有支撐散熱部之圓盤狀蓋部之電極者。 弟5圖係本發明貫施例4之放電燈之陽極的放大圖。第 5(A)圖係陽極之截面。第5(B)圖係陽極之背面側的側面圖。 13 200845100 在第5(A)及⑻圖中，省略與實施例3相同部分的說明。陽極 40係具有支撐散熱部之圓盤狀蓋部者。蓋部27係連接内部 導棒7與散熱部12之圓柱狀構件。i貫穿孔28係設於蓋部之 圓柱軸方向之貫穿孔。 5 蓋部27係配設於陽極40之凹部21内，並相對於内部導 棒7支撐散熱部I2。蓋部27係透過炫接或壓合固定於至少内 部導棒7或陽極40之凹部2卜蓋部27具有蓋貫穿孔^，並空 間的連接陽極40之凹部21之凹部底面23側與陽極4〇之躺體 面13側。蓋貫穿孔28係均等地設置4個於蓋部幻的圓周方 10向。由於具有蓋部27，因此可相對於内部導棒7穩定地固持 陽極40之散熱部12，並可防止前端部丨丨變形。再者，由於 藉由設置蓋貫穿孔28可將電極前端部！！之熱及凹部底面23 附近之熱有效地放出至陽極4〇之背面17側，因此可提高陽 極40之冷卻效果。 15 產業之可利用性 本發明之放電燈最適合作為電極之溫度上升少且可照 射紫外線的放電燈。 【圖式簡單說^明】 第1圖係本發明實施例1之放電燈的外觀圖。 20 第2(A)、（B)圖係本發明實施例1之放電燈之陽極之放 大圖。 第3(A)、（B)圖係本發明實施例2之放電燈之陽極之放 大圖。 第4(A)、（B)圖係本發明實施例3之放電燈之陽極之放 14 200845100 大圖。 第5(A)、（B)圖係本發明實施例4之放電燈之陽極之放 大圖。 第6(a)〜(c)圖係顯示習知放電燈之電極結構的概念圖。 5 【主要元件符號說明】 1...放電燈 15...前端側錐面 2...發光部 16···背面侧錐面 3...密封管部 17···背面 4...燈座 18...電極固持孔 5...外部導棒 21···凹部 6...金屬箔 22…凹部侧面 7...内部導棒 23…凹部底面 9…陰極 24...貫穿孔 10.20,30,40···陽極 25,35·.·内部口 11...前端部 26,36.·.外部口 12...散熱部 27...蓋部 13...軀體面 28...蓋貫穿孔 14...前端面 34...傾斜貫穿孔 15BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrode structure for a discharge lamp 5 of a short arc type or the like which is irradiated with ultraviolet rays, and more particularly to an increase in temperature of an electrode. The electrode structure of the discharge lamp. RELATED ART BACKGROUND OF THE INVENTION In general, in the case of forming a wiring pattern of a semiconductor, a short arc discharge lamp or the like which irradiates ultraviolet rays is used as a light source. The discharge lamp is passed through an electrode rod and held in a discharge space by a sealed tube made of quartz, and is vertically lit for use in an upper or lower anode. Therefore, it is well known that the discharge lamp becomes a high temperature state when it is lit. Further, when the discharge lamp is turned on, the anode will collide with the electrons sent from the cathode, and evaporation and consumption will occur due to the collision. Further, when the electrodes are consumed by the collision of electrons, the inner wall of the discharge lamp, particularly the inner tube wall from the central portion of the arc tube to the upper side, is blackened by heat convection. Furthermore, with the demand for high illumination in recent years, the discharge lamp has also been greatly heated, and the anode has also been enlarged. Since the large-sized anode is very heavy, the sealing structure composed of the electrode rod supporting the electrode and the sealing tube made of quartz 20 may be damaged by the movement of the discharge lamp or the like. For the above problems, there is a method of providing a hole or a groove to the anode to reduce the weight and adjusting the convection of the gas in the bulb to prevent the anode from being exothermic and blackening. In the following, several examples of conventional techniques related thereto will be cited. 5 200845100 The "short arc type discharge lamp" disclosed in Patent Document 1 is a lamp which changes the life of the blackening position in the discharge lamp. As shown in Fig. 6(a), the lamp is formed with a through hole extending from the front end side to the rear end side. When the anode is turned on above the cathode, the gas in the bulb flows through the through hole of the anode 5 by convection, so that the anode can be efficiently cooled. Since the gas flowing through the perforation flows to the rear of the anode, the evaporated anode constituent material is solidified at the end portion of the sealing portion, so that the central portion of the bulb is less likely to be blackened and the service life is longer. The "short arc type discharge lamp" disclosed in Patent Document 2 is a lamp which changes the direction of the air current in the discharge lamp to improve the light transmittance of the bulb. As shown in Fig. 6(b), the fourth (4) is provided with a projection and an annular groove at the rear end portion around the turn portion of the anode. First, the airflow is called and circulated along the projections and the annular groove, so that the strips are attached to the annular groove, the electrode rod and the bulb wall. As a result, the amount of evaporant adhering to the effective range of the central area of the bulb is significantly reduced by less than 15. Since the high illumination can be maintained, the service life becomes longer. The "anode electrode for a discharge lamp" disclosed in Patent Document 3 is an anode which prevents melting of the tip end portion and prevention of deformation. As shown in Fig. 6(e), the anode is provided with a cavity inside the anode, a gas inflow hole is provided at the front end portion, and a pressure e-circle is provided at the rear end portion or the side surface portion. Thereby, the high-temperature high-speed gas generated by smuggling the port arc from the gas inflow hole 20 is sucked into the cavity, and the heat month b is released from the inner wall of the anode to the outside. Since the cavity can be used for heat dissipation, heat energy can be effectively dispersed. [Patent Document] Japanese Laid-Open Patent Publication No. Hei. No. Hei. No. Hei. No. 2006-267934. Problem 5 However, the electrode of the conventional discharge lamp has the following problems. When the through hole is provided on the front end side of the anode, the gas in the bulb flows through the through hole, and the arc is shaken. When an abnormal discharge occurs near the through hole, the electrode is significantly consumed. When the protrusions are placed after the impurities, the anode becomes heavier. Even if the groove at the rear end of the anode is simply added, the air flow will not be changed. If the anode is provided with a cap portion and a cavity is provided, the processing and quality management of the melted portion becomes complicated. If the anode is provided with a hole for the gas outlet at the side portion, the evaporated electrode material is blown to the central portion of the bulb, so that the blackening of the effective use area of the bulb becomes conspicuous. SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and to provide a long life of an electrode 15 of a discharge lamp which is excellent in heat dissipation and discharge stability, is lightweight, does not damage internal guide bars and sealed tubes, and is easy to manufacture and which is not easily blackened. Means for Solving the Problem In order to solve the aforementioned problems, in the present invention, the electrodes of the discharge lamp are inside. A recess having a depth greater than the aperture is formed around the connecting portion of the connecting rod, and the discharge lamp includes an arc tube; an opposite cylindrical electrode for the arc tube; and an inner guide rod for holding the electrode in the arc tube. Further, the present invention is formed with a through-hole "through" which penetrates from the side surface side opening portion of the electrode to the recess portion side opening portion, and the side surface side opening portion is closer to the discharge portion side of the electrode than the concave portion side opening portion. Further, when the height of the column of the electrode is L1 and the depth of the recess is 200845100 h, then (1^/3) <^<(21^/3). When the outer diameter of the electrode is D, the maximum outer diameter of the inner inner guide bar is A, and the maximum of the concave portion is D3, then ((Uxpi - D2)) <D3<(1 · 1 x (D Factory D2)) 〇Inventive effect 5 11 With the above structure, after the column electrode of the sand can be turned off, the heat in the vicinity of the tip end portion of the electrode is released to the inner guide rod side, so that the weight can be reduced and Improve heat dissipation and extend discharge life. The through hole can improve the heat dissipation effect. C. Embodiments 10 Best Mode for Carrying Out the Invention Hereinafter, the best mode for carrying out the invention will be described in detail with reference to Figs. 1 to 5. [Embodiment 1] Embodiment 1 of the present invention is a discharge lamp which uses an anode which is held by an inner guide bar on the side opposite to the discharge point and has a deep recess on the back side. Fig. 1 is an external view of a discharge lamp of Embodiment 1 of the present invention. Figure 2 is an enlarged view of the anode having a recess on the back side. Figure 2(A) shows the appearance of the anode. Fig. 2(B) is a cross-sectional view taken along line B-B of Fig. 2(A). In the i-th and second figures, the discharge lamp 1 is a lamp that discharges between internal electrodes. The anode 1 is the electrode of the positive side 20. The cathode 9 is an electrode on the negative side. The inner guide bar 7 is a member that supports the electrodes and supplies electricity. The sealed tube portion 3 is a portion that hermetically seals the bulb. The outer guide 5 is a member that is supplied from the socket through the metal foil to the electrode. The light-emitting portion 2 is a portion that emits light by discharge between electrodes, and is a glass member that seals the electrodes to form a discharge space. The lamp holder 4 is a mechanically held lamp and is used to supply power to the 200845100 piece. The recessed portion 21 is a cylindrical hole provided from the back surface toward the front end surface. Here, the case where the concave portion 21 is provided at the anode 1 is used, but it is also applicable to the cathode $. Next, the meniscus action of the discharge lamp of the embodiment of the present invention having the above-described configuration will be described. First, the function of the discharge lamp will be described with reference to Fig. 1 . The discharge lamp 1 includes a light-emitting portion 2, two sealed tube portions 3, an anode 1 and a cathode 9 disposed opposite to each other in the light-emitting portion 2, and an internal guide rod 7 that supports the anode (7) and the cathode 9 and is energized. The outer guide bar 5 and the sealed tube portion 3 which is connected to the inner guide bar 7 and the outer guide bar 5 by the conductive metal foil 6 and hermetically sealed. Further, the sealed tube portion 3 is fixed with the socket 4, and the other sealed portion 3 is also fixed with the socket 4. The discharge lamp 1 is fixed to the light source device through the socket 4. Further, the back surface of the anode 10 (the bottom surface of the cylinder on the side of the sealed tube portion) is provided with a concave portion 21. In the present embodiment, a pair of cylindrical electrodes are held by the inner guide bars 7 so as to oppose each other in the arc tube. Further, a recess having a deeper hole diameter is formed around the joint portion of the anode 1 which is connected to the inner guide rod 7. In the present embodiment, the heat in the vicinity of the front end portion of the anode 1 is released to the side of the inner guide rod 7 by the concave portion 21 of the end surface after the cylindrical anode 10. Further, when the height of the cylinder of the anode 1 is ", and the depth of the concave portion 21 is & then, (Ll / 3) < L2 < (2Li / 3). When the outer diameter of the anode 1 is 〇 The maximum outer diameter of the inner guide bar 7 in the recess 21 is the maximum diameter of the concave portion 20, then (〇.7x(Dl - D2)) <D3<(Ux(Di_D2)) 〇, The function of the anode will be described with reference to Fig. 2. The front end portion 11 is a cylindrical portion of the anode 10 and is held by the inner guide bar 7. The heat radiating portion is connected to the front end portion and has a concave portion 21 therein. The cylindrical portion of the anode 10. The front end surface 14 is the upper surface of the cylindrical electrode and is discharged between the cathodes 9 of 200845100. The body surface 13 is the cylindrical side surface of the electrode, and the back surface is the cylindrical bottom surface of the anode 10. The recessed portion 21 is provided as a cylindrical hole from the back surface toward the front end surface. The recessed side surface 22 is an inner side surface on the circumference of the cylindrical recessed portion 21. The recessed bottom surface 23 is a bottom surface of the cylindrical recessed portion 21. The electrode holding 5 hole 18 is provided in The hole of the bottom surface 23 of the recess. The total length of the electrode is the length of the anode in the direction of the cylinder axis. The depth of the recess L2 is The back surface π is the length of the bottom surface 23 of the recess in the direction of the cylindrical axis. The outer diameter Di is the outer diameter of the body surface 13 of the anode. The outer diameter 〇 2 is the outer diameter of the inner guide rod 7. The outer diameter is the inner diameter of the circumferential side of the recess 21 0 10 15 20 The anode ίο has a substantially cylindrical shape and is composed of a front end surface 14, a front end side tapered surface 15, a body surface 13, a back side tapered surface 16, a back surface 17, and a concave portion. The concave portion 21 is formed by the concave side surface 22 and The bottom surface of the concave portion is formed by arranging the inner conductive rod 7 into the electrode holding hole 18 provided on the bottom surface 23 of the concave portion, so that the anode can be trapped in the discharge space. When the difference of D#D3 is too small, the heat dissipation (four) becomes thin. Therefore, the anode 1() may be deformed by the heat at the time of lighting the lamp or (4) when the lamp is manufactured. When the difference of D4D2 is too small, the volume of the recess 21 becomes small, so that the anode H) is lightened and released. The effect of the heat of the electric part will also become smaller. When the difference between the red ship 2 is too small, the bottom surface 23 of the recess and the front end _ will be too close to the bottom surface 23 and the front end surface 1 are close to 4, the bottom surface of the electrode holding hole 18 is also The sin is near the front end, so it is impossible to deepen the electrode holding hole. When the money is deepened _ holding the hole 18, the electricity _ holding the hole 1 coffee The guide bar 7 is suitable for the stomach (4) m (four) the guide bar 7 is detached. In particular, when the lamp and the anode electrode are thermally expanded and contracted, it is easier to detach the 0 0 200845100 when the column height of the anode ίο is L1, and When the depth of the concave portion 21 is L, (WWPW3) is appropriate. The minimum outer diameter of the body portion of the anode 1 is Di, and the maximum outer diameter of the inner guide rod 7 disposed in the concave portion 21 is D2. When the large diameter of the concave portion 21 is d3, then (〇.7x (Di. 5 (1.lx (Dl - 2)) is more appropriate. By satisfying the foregoing conditions, the cooling effect of the anode 10 can be improved, deformation of the anode 10 can be prevented, and the anode 10 can be prevented from falling off due to heat. Further, by making the anode 10 lighter, it is possible to prevent the inner guide bar 7 from being bent and the seal tube from being damaged. Therefore, the life of the lamp can be extended. Further, by providing the fine groove on the surface of the heat radiating portion 12, the cross-sectional area of the heat radiating portion 12 10 can be enlarged, and the heat radiating effect of the heat radiating portion 12 can be enlarged. As described above, in the first embodiment of the present invention, since the structure of the discharge lamp is held by the inner guide bar on the opposite side of the pen point, and has the % pole of the deep recess on the back side, it is possible to use the cylindrical electrode. The concave portion of the end surface discharges the heat in the vicinity of the front end portion of the electrode to the inner guide rod side, so that the electrode can be lightly weighted, the heat dissipation effect can be improved, and the service life of the discharge lamp can be prolonged. [Embodiment 2] Embodiment 2 of the present invention is a discharge lamp which uses an electrode having a concave portion on its back surface and having a through hole penetrating from the body surface to the inside of the concave portion. Figure 3 is an enlarged view of the anode of the discharge lamp of Example 2 of the present invention. Figure 20 3(A) shows the appearance of the anode. Fig. 3(B) is a B-B cross-sectional view of Fig. 3(A). In the third (A) and (B) drawings, the anode 20 is a positive electrode having a through hole penetrating from the body surface to the inside of the recess. The through hole 24 connects the holes of the body surface 13 and the recess 21. The inner port 35 is an opening portion of the side surface of the recessed portion of the through hole 24. The outer port 36 is an opening portion of the body surface side of the through hole 24. As shown in Fig. 11 200845100 3 (A) and (B), the heat radiating portion 12 of the anode 20 is provided with a through hole 24 connecting the body surface 13 and the recess portion 21. The through holes 24 are equally provided with four circumferential directions of the heat radiating portions 12 of the electrodes. By providing the beryllium holes 24 in the heat dissipating portion 12', it is possible to raise the cooling effect in the recess 21 of the anode 2 which is 5 in high temperature when lighting. Further, since the external port 26 penetrating the through hole 24 of the recessed portion 21 is provided on the body surface 13, the discharge is not unstable by the convection flowing into the through hole 24, and the vicinity of the mouth portion 26 outside the through hole 24 is not An abnormal electrode consumption is generated. Therefore, the life of the lamp can be extended. Here, an example in which four through holes are provided in a circumferential direction is described, but it is not limited to 10 4 or 6 holes. Since the cross-sectional area of the heat radiating portion 12 becomes small, the effect of cooling the front end portion 11 may be lowered by the heat transfer from the front end portion of the anode 2 to the heat radiating portion 12. Therefore, the diameter and number of the through holes μ must be appropriately set. [Embodiment 3] Embodiment 3 of the present invention is a discharge lamp which has an electrode having a concave portion on its back surface and having a through hole penetrating from the body surface to the inside of the concave portion and inclined toward the front end surface side of the electrode. Fig. 4 is an enlarged view showing the anode of the discharge lamp of Example 3 of the present invention. Figure 4(A) shows the appearance of the anode. Figure 4(B) is a B_B wearing surface of Figure 4(A). In the fourth (A) and (B) drawings, the anode 30 is a positive side electrode having a hole which is inclined toward the front end surface side of the electrode. The inclined through hole 34 connects the hole of the body surface 13 and the concave portion 21, and is inclined toward the front end surface 14 side. The inner port 35 is an opening portion on the side of the concave side surface 22 of the penetrating through hole %. The outer port 36 is an inclined portion of the through-hole "on the body surface 13 side, and is closer to the front end surface 12 than the inner port 35. The distance between the L3-series inner port 35 and the outer port 36 is the direction of the electrode. As shown in the fourth (A) and (B), the inclined through-hole outer-portion portion 36 is inclined toward the distal end surface 14 side from the inner-portion portion 35, and enters the distal end portion 11 side from the heat radiating portion 12. 5 The inclination of the front end portion 11 of the anode 3 is efficiently radiated by the inclined through hole 34 toward the front end surface 14. When the concave bottom surface 23# is close to the anode 3 front end 14, the anode 30 and the inner guide 7 The fitting may become insufficient, but when the inclined through hole 34 is actually close to the front end face 14, the cooling effect of the front end portion 11 can be improved. Since the cooling effect of the front end portion of the anode 3 is high, The deformation of the anode 30 can be prevented, and the anode 3 can be prevented from falling off due to heat. Further, since the outer port of the oblique through hole 34 penetrating the recessed portion 21 is allowed to be placed on the body surface 13, the discharge is not penetrated by the inflow. The hole % is convective and unstable, and is inclined to the outside of the hole 34. There is no abnormal electrode consumption in the vicinity, so the life of the lamp can be extended. However, since the deformation of the anode 30, the unstable discharge, and the abnormal consumption of the anode 30 may occur, the position must be appropriately set. The mouth portion 36 of the inclined through hole 34 is not too close to the front end face 14. Embodiment 4 The present invention is a discharge lamp which has a recessed portion on the back surface and has a through surface from the body surface to the inside of the recess and An electrode having a disc-shaped lid portion that supports the heat dissipating portion, and an electrode having a disc-shaped lid portion for supporting the heat dissipating portion. Fig. 5 is an enlarged view of the anode of the discharge lamp of the fourth embodiment of the present invention. Fig. 5(A) The cross section of the anode. Fig. 5(B) is a side view of the back side of the anode. 13 200845100 In the fifth (A) and (8) drawings, the description of the same portions as in the third embodiment will be omitted. The anode 40 has a heat dissipating portion. The lid portion 27 is a cylindrical member that connects the inner guide bar 7 and the heat dissipating portion 12. The through hole 28 is formed in a through hole in the cylindrical axis direction of the lid portion. Inside the recess 21 of the anode 40, and relative to the inner guide 7 Supporting the heat dissipating portion I2. The lid portion 27 is fixed to the recessed portion 2 of at least the inner guide rod 7 or the anode 40 by being spliced or press-fitted. The cover portion 27 has a cover through hole, and a recess of the recess 21 of the anode 40 is spatially connected. The bottom surface 23 side and the anode body 4 are located on the side of the lying surface 13. The cover through-holes 28 are equally provided with four circumferential directions 10 in the cover portion. Since the cover portion 27 is provided, it can be stably held relative to the inner guide rod 7. The heat dissipating portion 12 of the anode 40 prevents the front end portion from being deformed. Further, since the cover through hole 28 is provided, the heat of the electrode front end portion and the heat of the concave portion bottom surface 23 can be efficiently discharged to the anode 4A. The back side 17 side can improve the cooling effect of the anode 40. 15 INDUSTRIAL APPLICABILITY The discharge lamp of the present invention is most suitable as a discharge lamp having a small temperature rise of an electrode and capable of illuminating ultraviolet rays. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is an external view of a discharge lamp according to a first embodiment of the present invention. 20 (A) and (B) are enlarged views of the anode of the discharge lamp of Embodiment 1 of the present invention. 3(A) and (B) are enlarged views of the anode of the discharge lamp of Example 2 of the present invention. 4(A) and 4(B) are diagrams showing the anode of the discharge lamp of Embodiment 3 of the present invention. 5(A) and (B) are enlarged views of the anode of the discharge lamp of Example 4 of the present invention. Figures 6(a) to (c) are conceptual diagrams showing the electrode structure of a conventional discharge lamp. 5 [Description of main component symbols] 1...Discharge lamp 15...Tail-side tapered surface 2...Light-emitting portion 16···Back side tapered surface 3...Sealed tube portion 17···Back surface 4.. Lamp holder 18...electrode holding hole 5...outer guide bar 21···recessed part 6...metal foil 22...recessed side surface 7...internal guide bar 23...recessed bottom surface 9...cathode 24... Through hole 10.20, 30, 40···Anode 25, 35·.·Internal port 11...Front end portion 26, 36.. External port 12... Heat sink portion 27... Cover portion 13... Body Face 28... cover through hole 14... front end face 34... inclined through hole 15