201232600 六、發明說明： 【發明所屬之技術領域】 本發明是關於金屬鹵素燈及金屬鹵素燈點燈裝置。 【先前技術】 在液晶顯示面板的製造製程中，貼合玻璃基板時，適 合利用長弧型之金屬鹵素燈來作爲用以使塗佈在玻璃基板 與及玻璃基板之間的密封劑硬化的紫外線光源。在此製造 製程中，是使用具備有棒狀的金屬鹵素燈以及配置於其背 面的反射鏡的點燈裝置。 於第4圖顯示該裝置。是將金屬鹵素燈61配置於燈外 殻60內。於金屬鹵素燈61的上方配置有反射鏡62，來自燈 的輻射光線照射於設置在下方的工件W »工件W係如上所 述，於玻璃基板6 3與玻璃基板6 4之間塗佈有密封劑6 5者》 如此用途下，依照密封劑6 5的特性，需要波長3 0 0〜 4 OOnm區域的紫外線照射，因此適宜使用於發光管內部封 入有鐵的金屬鹵素燈61，因鐵於上述波長帶中可以取得良 好光輻射。 近來’在上述的液晶顯示面板的製造製程中，爲了降 低製造時所要需要的電力量爲目的，因此將金屬鹵素燈的 輸入電力在工件照射時及非照射時之間進行切換，以減低 非照射時的電力之方式來進行。例如，爲了處理1個工件 ，對工件以比較高的電力將燈予以點燈數十秒鐘，然後將 照射結束後的工件移走，到下一工件被搬送過來爲止之間 -5- 201232600 ，數十秒鐘是遮斷光的照射而切換成比較低的電力來點燈 0 說明如此之點燈方法的一例，在點燈初期，上所述之 「比較高的電力」是與「比較低的電力」相同程度，不過 隨著燈的使用時間經過，燈產生劣化，當照射於工件的光 放射量減少時，就只須提升作爲「比較高的電力」之期間 的電力値。例如，在相對於燈初期的光輻射量減少5 %之 時點時，則以藉由將比較高的電力回復至初期的光輻射量 之方式來調整（上昇）電力値，以補償隨著燈的累積點燈 時間所產生的照度降低。如此地，燈的電流、電壓、電力 是隨著燈的使用而隨時變化。 又，所謂比較高的電力，例如是相對於額定消費電力 高50%以上的電力，而比較低的電力，是以比比較高的電 力還低的電力之方式所設定的電力。又，在此爲了方便， 把以比較高的電力進行點燈的模式稱之爲「定常電力點燈 模式」；以比該定常電力點燈模式還低的電力來提供電流 ，也就是將比較低的電力進行點燈的模式稱之爲「節省電 力點燈模式」。 如此地，藉由定常電力點燈模式與節省電力點燈模式 來交互切換較高電力與較低電力，也就是利用進行所謂的 擬似性的間歇點燈，將金屬鹵素燈以省電方式驅動之同時 ，相較於將燈進行ΟΝ/OFF來切換可以使燈的起動性快速 地進行，而實現將多數的工件連續性地處理。 第5圖，是關於先前技術之金屬鹵素燈5 0的說明圖， 201232600 且是以通過管軸的面所切斷後的斷面圖。如圖所示，金屬 鹵素燈50係於發光管51的兩端具備有封止部55a，於封止 部55a內，埋設有鉬箔54。 電極52爲於鎢中含有氧化钍之钍氧鎢製，電極52的軸 部朝向封止部延伸，並接連於前述的鉬箔54。於電極軸部 53的周圍，配置有石英玻璃製的筒狀保持構件56,該保持 構件56的外周面與發光管51的內周面熔著而接合著。 在此，將上述金屬鹵素燈以具體的數値例表示，發光 管51的外徑爲26.1 mm、內徑爲22.5mm (壁厚1.8 mm)、包 含封止部全長600mm、電極間的距離（發光長度）爲 5 00mm ° 位在電極52前端部分的粗徑部外徑爲3.5mm，由較細 外徑所構成之軸部53的外徑爲2.5mm。 又，石英玻璃製之保持構件56的內徑爲2.6mm，其全 長設爲2mm。 鉬箔54，在此是在一方的封止部中配置有2片，該全 長爲31mm，並使之中介有由石英玻璃所構成之桿狀的密 封用構件而被收縮密封著。 又，被封入於發光管51的封入物，爲稀有氣體、預定 量的鹵素、及至少有鐵。燈的輸入電力爲7kW〜14kW，輸 入電流7A〜28A。 〔先前技術文獻〕 〔專利文獻1〕日本特開2006-1 347 1 0號公報 201232600 【發明內容】 〔發明所欲解決之問題〕 然而，在以如上述般之將較高輸入與較低輸入交互切 換間歇點燈之方式使該金屬鹵素燈動作時，作爲發光物質 所封入的金屬鹵化物，由於在鹵素燈點燈中會偏移存在比 較低溫部的封止部，所以無法取得該等封入物（金屬）之 有效的發光，而會有照度降低的情形。 再者，於封止部所偏析的金屬鹵化物，會有與埋設於 封止部的鉬箔反應而產生腐蝕，造成不能維持導通的不良 情形。又，爲了抑制如此之與鉬箱反應，亦能夠設計成相 較於以往更加提高封止部溫度之構造來實施防止金屬鹵化 物進入。然而在實際上，若是將溫度提升至可以抑制封入 物滲入之程度時，由於會使鉬箔暴露於高溫而使箔片溶斷 之源於其他因素造成的不良情形，所以即使提高了封止部 的溫度，也不能謀求鹵素燈的長壽命化。 在此，爲了不使金屬鹵化物往位於長弧型金屬鹵素燈 的封止部造成偏析，因而形成箔片腐蝕、或藉由高溫化所 造成的箔片熔斷等不良情況，因此本發明的目的，是在於 提供一種藉由一面使封止部溫度下降，同時藉由對封入金 屬下工夫硏創，使金屬鹵化物不會滲入封止部的金屬鹵素 燈；再者，是在於提供一種使供電裝置具備定常電力點燈 模式與節省電力點燈模式，並藉由切換電流來點燈之特有 的點燈方法，即使是在鹵素燈點燈時也可以避免金屬鹵素 燈有上述不良情況，而可以增長鹵素燈之使用壽命的金屬 -8- 201232600 鹵素燈點燈裝置。 〔發明解決問題之技術手段〕 (η本發明之金屬鹵素燈，是在石英玻璃製之發光 管的內部以含有鐵來作爲發光物質， 於上述發光管的兩端具備有用以支撐電極之軸部的保 持用筒體，並且於封止部埋設有鉬箔而成的金屬鹵素燈， 其特徵爲： 將上述保持用筒體的長度設爲L( mm)，將燈的電流 設爲1(A)時，L/I(mm/A)爲0.17以上，並且 於上述發光管的內部，封入有：錫、鉍、鎵、鉛與鋅 當中之至少1種。 (2)又，本發明之金屬鹵素燈點燈裝置，是由具備 有：對上述金屬鹵素燈供給電力的供電裝置所成的金屬鹵 素燈點燈裝置，其特徵爲： 上述供電裝置，係具備：定常電力點燈模式、及以比 定常電力點燈模式還低之電力來供給電流的節省電力點燈 模式者。 〔發明效果〕 (1) 可以抑制金屬往封止部進入，而可以防止箔的 腐蝕及熔斷，故可以長時間維持金屬發光，而可以製成長 壽命的金屬鹵素燈。 (2) 對於金屬鹵素燈點燈裝置，藉由切換：定常電 -9 - 201232600 力點燈模式、及以比上述定常電力點燈模式還低之電力來 供給電流的節省電力點燈模式而可以以節省電力方式進行 點燈，並且可以將金屬鹵素燈製成在進行如此之電力切換 時，亦較少因發光物質損失而形成照度降低者。 【實施方式】 以下，依據實施例來說明本發明的實施形態。 第1圖，是顯示本發明之長弧型金屬鹵素燈的基本構 成，是以管軸方向所切斷的斷面圖。金屬鹵素燈10係於發 光管11的兩端具備有封止部lla，並於封止部lla內，使鉬 箔Μ與電極12作電性接連。發光管11是由對紫外線有優秀 透過性的石英玻璃所構成。 於第2圖，電極12是於鎢中含有氧化钍的钍氧鎢製， 電極12的軸部朝向封止部延伸，接連於前述的鉬箔54、再 接連於外部導引棒15。於電極軸部13的周圍，配置有石英 玻璃製的筒狀保持構件16，該保持構件16的外周面與發光 管11的內周面熔著而接合著，來使電極軸部13成爲被保持 的狀態。 於該金屬鹵素燈10中，於發光管11的內部S至少包含 有發光物質’而作爲發米物質至少包含有鐵。鐵在此種的 金屬鹵素燈10中’是用以取得作爲主要發光之波長3 〇〇nm 〜400nm範圍的紫外線而被封入的必須發光物質。又，亦 可與鐵同時封入水銀。 於第2圖是顯示封止部1U的放大圖。在本發明中，以 -10 - 201232600 在電極軸部13之周圍所配置之石英玻璃製保持構件16的長 度爲L ( mm )、鹵素燈的電流I爲（A )時，其L/I ( mm/A )的關係是設成〇 . 1 7以上。此乃由於燈的電流値較大之情 形時電流密度較高，所以封止部1 1 a附近的熱量也變得較 高，因此熱的影響相對於被埋設在封止部11a的鉬箔14就 會更大，所以藉由將保持構件16的長度，因應電流的大小 來加長，使鉬箔1 4的位置遠離放電空間S。其結果，可以 避免鉬箔14高溫化而溶斷，而可以安定地維持電流供給狀 態。 又，如上述般地，燈的電流，由於有時是被設定成會 依燈之光照射量的衰減而慢慢地提高，所以最高到達電流 是隨著燈的累積點燈時間經過而變化（變較高），不過燈 的輸入電流並不是一直超過燈的額定消費電流以較高方式 來設定。因此，在上述L/I( mm/A )的關係中，對於I ( A )，是藉由使用額定消費電流的値來預先設定保持構件16 的長度L ( mm )，則無論以何種點燈狀態來驅動燈，都可 以防止封止部的過熱，而可以安定地驅動。 另一方面，若以滿足上述關係L/I 2 0.1 7之方式來將保 持構件16的長度製成比以往更長之情形時，由於隨著保持 構件16的加長會增大放電空間S與鉬箔14之端部K的溫度差 之緣故，滲入到鉬箔14之端部K之金屬鹵化物的量會增大 。於如此之情形時，放電空間S內之金屬的發光量會減少 而造成照度降低。 在此爲了避免如此之金屬鹵化物的損失’因此在本案 -11 - 201232600 發明中，以封入蒸氣壓比鐵還高的特定金屬爲特徵，雖然 其無法直接地貢獻在發光上。具體而言，是封入錫、鉍、 鎵、鉛與鋅之任一種金屬。此等特定的金屬，可簡便地以 適宜之鹵素化合物的狀態來進行封入。 上述特定的金屬群，由於是蒸氣壓比鐵還高的物質’ 因此藉由該等金屬與鐵（Fe)產生複合化合物，在鹵素燈 點燈中，可以增高蒸氣壓。此結果，可以使以往滲入於密 封部的鐵不會進入到封止部11 a之鉬箔14的附近K，而可以 保留在放電空間S。 在此，舉出對於鐵之上述金屬的封入比例的例子，原 子比於錫（Sn )與鐵（Fe)的比例Sn/Fe爲0.25，鉍（Bi ) 與鐵（Fe)的比例Bi/Fe爲0.14。當然，對於其他的金屬， 也是與鐵的原子比在適切範圍來進行封入爲佳。 依據如此之本案發明，凡起因於所謂交互反覆進行定 常電力點燈模式與比定常電力點燈模式還低之節省電力點 燈模式來將金屬鹵素燈點燈，而對於發光管之熱分布狀態 產生顯著的不均一之情形、或發光物質滲入封止部內部而 使照度降低、或因埋設於封止部的鉬箔與金屬鹵化物反應 並腐蝕而有損供電部的導通狀態、或是鉬箔過熱而溶斷等 全部問題皆可以消除，因而可以提供維持長時間安定照度 的金屬鹵素燈。 以下，說明本發明的實施例，不過於本發明並不受後 述構成所限定。 製作了基本上具備有由第3圖所示之金屬鹵素燈所構 -12- 201232600 成的各種燈。 發光管的材料爲石英玻璃，管外徑爲26.1mm，內徑爲 22.5mm (壁厚 1.8mm)。 作爲發光物質，是將鐵以〇.〇1 lmg/cc的比例封入，將 水銀以0.1 7mg/CC的比例封入。鐵、錫是相同於上述比例 來封入。又，作爲蒸氣壓比鐵還高之金屬，是將錫（Sn) ，相對於鐵的原子比以Sn/Fe= 0.25的比例來封入》 製作了實施例1〜7的金屬鹵素燈，其中變動發光管的 長度及電極間距離的長度，使電流爲7(A)〜28(A)， 又，配置於發光管兩端之保持構件的長度L爲4.8 (mm)〜 13.2 (mm)、使L/I的大小爲0.17〜1.89的範圍。 又，製作了作爲比較例的金屬鹵素燈，其中於發光管 內部並無封入上述之蒸氣壓比鐵還高的任一特定金屬，保 持構件的長度L相對於燈電流爲0.07〜0.13。又電流I爲15 A 〜27A、電極間距離爲1100mm、保持構件長度爲2mm。 將上述實施例1〜7及比較例1的金屬鹵素燈的各個， 分成額定消費電力與相對於額定消費電力大約爲50%以下 之電力的兩段階，每30秒鐘切換點燈。其結果，比較例1 的金屬鹵素燈，在542小時點燈後鉬箔過熱而熔斷不亮燈 。對於其他實施例1〜7的金屬鹵素燈，皆於1 000小時點燈 後，鉬箔的狀態並無變化，且也沒有看到金屬鹵化物凝聚 的樣子》 依據以上所說明之本案發明，爲了較低地維持埋設於 封止部 '之鉬箔的溫度，利用增長電極軸部的保持構件，且 -13- 201232600 相對於燈的電流增長爲0.1 7mm/A以上之方式，可增長放電 空間與鉬箔的距離而可以避免該箔造成溶斷的問題，並且 藉由使鉬箔的附近更低溫化，雖然放電空間內的金屬鹵化 物會變得更易於滲入，不過對於作爲主要發光物質的鐵則 藉由封入更高蒸氣壓的特定金屬，使所封入的特定金屬與 鐵（Fe )，形成複合化合物而使蒸氣壓變高，其結果，能 夠使金屬鹵化物安定地保留在放電空間。 又藉由實施如此之構成，對於交互進行高輸入與低輸 入之間歇點燈動作而言，可以製成較強的金屬鹵素燈，除 此另一方面，當長時間使用時，作爲更進一步的問題是由 於電極在間歇點燈下的伸縮，會有造成鉬箔與電極的接合 脫落之問題。對於如此的問題，藉由將埋設於封止部之鉬 箔的片數增加成2片以上，來提升熔接部的強度，便可以 製成更加長壽命的金屬鹵素燈。 又，本案發明，當然是不受上述實施形態及實施例的 內容所限定而能夠加以適當地變更。例如，在上述實施例 中雖是與鐵同時封入水銀來作爲發光物質，但僅以鐵來實 施亦可。在沒有封入水銀之情形時，可以藉由增加所封入 之稀有氣體的量或是縮小發光管的管徑，來取得與封入有 水銀時相同的電流値。 【圖式簡單說明】 第1圖是顯示本案中之金屬鹵素燈之管軸方向斷面圖 -14- 201232600 第2圖是說明要部的放大圖。 第3圖是歸納實施例中的燈與比較例中的燈之l /1的圖 表。 第4圖是用以說明液晶面板製造中之光照射裝置的圖 面。 第5圖是顯示先前技術之金屬鹵素燈之構成的圖面。 【主要元件符號說明】 10 :金屬鹵素燈 11 :發光管 11a :封止部 12 :電極 13 :電極軸部 1 4 :鉬箔 15 :外部導引棒 16:電極軸部保持構件 S :放電空間 K :鉬箔電極側端部 -15-201232600 VI. Description of the Invention: [Technical Field of the Invention] The present invention relates to a metal halide lamp and a metal halide lamp lighting device. [Prior Art] In the manufacturing process of a liquid crystal display panel, when a glass substrate is bonded, a long-arc metal halide lamp is suitably used as an ultraviolet ray for hardening a sealant applied between a glass substrate and a glass substrate. light source. In this manufacturing process, a lighting device having a rod-shaped metal halide lamp and a mirror disposed on the back thereof is used. The device is shown in Figure 4. The metal halide lamp 61 is disposed in the lamp housing 60. A mirror 62 is disposed above the metal halide lamp 61, and the radiation from the lamp is irradiated onto the workpiece W provided below. The workpiece W is coated with a seal between the glass substrate 63 and the glass substrate 64 as described above. In the case of such a use, in accordance with the characteristics of the sealant 65, ultraviolet irradiation in a region of a wavelength of 300 to 400 nm is required, and therefore it is suitably used in a metal halide lamp 61 in which an iron is sealed inside the arc tube. Good light radiation can be achieved in the wavelength band. Recently, in the manufacturing process of the liquid crystal display panel described above, in order to reduce the amount of electric power required for manufacturing, the input electric power of the metal halide lamp is switched between the irradiation of the workpiece and the non-irradiation to reduce the non-irradiation. The way of electricity is carried out. For example, in order to process one workpiece, the lamp is turned on for a relatively high power for several tens of seconds, and then the workpiece after the irradiation is removed, until the next workpiece is transported, -5-201232600, For tens of seconds, the illumination of the blocking light is switched to a relatively low power to turn on the light. 0 An example of such a lighting method is that at the beginning of lighting, the "higher power" described above is lower. The electric power is the same, but the lamp is deteriorated as the use time of the lamp passes, and when the amount of light emitted to the workpiece is reduced, it is only necessary to increase the power 作为 during the period of "higher electric power". For example, when the amount of light radiation at the initial stage of the lamp is reduced by 5%, the power 値 is adjusted (rised) by returning the relatively high power to the initial amount of light radiation to compensate for the lamp. The illuminance produced by the accumulated lighting time is reduced. In this way, the current, voltage, and power of the lamp change with time as the lamp is used. Further, the relatively high electric power is, for example, electric power that is 50% or more higher than the rated power consumption, and the relatively low electric power is electric power that is set to be lower than the relatively high electric power. Moreover, for convenience, the mode of lighting with relatively high power is referred to as "constant power lighting mode"; the current is supplied with lower power than the constant power lighting mode, that is, it will be relatively low. The mode in which the power is turned on is called "saving power lighting mode". In this way, the constant power lighting mode and the power saving lighting mode are used to alternately switch between higher power and lower power, that is, using a so-called quasi-like intermittent lighting to drive the metal halide lamp in a power-saving manner. At the same time, the switching of the lamp can be performed more quickly than when the lamp is turned on/off, so that most of the workpieces are processed continuously. Fig. 5 is an explanatory view showing a metal halide lamp 50 of the prior art, 201232600, and is a cross-sectional view taken along the plane passing through the tube axis. As shown in the figure, the metal halide lamp 50 is provided with a sealing portion 55a at both ends of the arc tube 51, and a molybdenum foil 54 is embedded in the sealing portion 55a. The electrode 52 is made of tantalum tungsten containing ruthenium oxide in tungsten, and the axial portion of the electrode 52 extends toward the sealing portion and is connected to the molybdenum foil 54 described above. A cylindrical holding member 56 made of quartz glass is disposed around the electrode shaft portion 53, and the outer peripheral surface of the holding member 56 is fused and joined to the inner peripheral surface of the arc tube 51. Here, the metal halide lamp is represented by a specific example, and the outer diameter of the arc tube 51 is 26.1 mm, the inner diameter is 22.5 mm (wall thickness: 1.8 mm), and the total length of the sealing portion is 600 mm, and the distance between the electrodes ( The light-emitting length was 500 mm. The outer diameter of the large-diameter portion of the tip end portion of the electrode 52 was 3.5 mm, and the outer diameter of the shaft portion 53 composed of the thin outer diameter was 2.5 mm. Further, the holding member 56 made of quartz glass has an inner diameter of 2.6 mm and a full length of 2 mm. In the molybdenum foil 54, two sheets are disposed in one of the sealing portions, and the entire length is 31 mm, and a rod-shaped sealing member made of quartz glass is interposed and contracted and sealed. Further, the enclosure enclosed in the arc tube 51 is a rare gas, a predetermined amount of halogen, and at least iron. The input power of the lamp is 7 kW to 14 kW, and the input current is 7A to 28A. [Prior Art Document] [Patent Document 1] Japanese Patent Laid-Open No. Hei. No. 2006-1 347 No. 10 201232600 [Disclosure] [Problems to be Solved by the Invention] However, higher input and lower input are used as described above. When the metal halide lamp is operated by the intermittent switching of the metal halide lamp, the metal halide enclosed by the luminescent material is offset by the sealing portion of the relatively low temperature portion in the halogen lamp lighting, so that the sealing cannot be obtained. The effective luminescence of the object (metal), and the illuminance is reduced. Further, the metal halide segregated in the sealing portion may be corroded by reacting with the molybdenum foil embedded in the sealing portion, resulting in failure to maintain conduction. Further, in order to suppress such a reaction with the molybdenum box, it is also possible to design a structure for preventing the entry of metal halides in comparison with the conventional structure in which the temperature of the sealing portion is further increased. However, in practice, if the temperature is raised to such an extent that the penetration of the sealant can be suppressed, the sealing of the foil due to exposure of the molybdenum foil to high temperatures causes a problem due to other factors, so that even if the sealing portion is raised The temperature of the halogen lamp cannot be extended. Here, in order not to cause segregation of the metal halide to the sealing portion of the long arc type metal halide lamp, the foil is corroded or the foil is blown due to the high temperature, and the like, and the object of the present invention is therefore It is to provide a metal halide lamp in which the metal halide does not penetrate into the sealing portion by lowering the temperature of the sealing portion while causing the metal to be sealed, and further, providing a power supply device With the constant power lighting mode and the power saving lighting mode, and by switching the current to illuminate the unique lighting method, even when the halogen lamp is lit, the metal halide lamp can be prevented from having the above-mentioned problems, and can be grown. Metal -8- 201232600 halogen lamp lighting device for the life of halogen lamps. [Technical means for solving the problem] (The metal halide lamp of the present invention contains iron as a light-emitting substance in an arc tube made of quartz glass, and has a shaft portion for supporting the electrode at both ends of the light-emitting tube. A metal halide lamp in which a retaining cylinder is embedded with a molybdenum foil in a sealing portion, wherein the length of the holding cylinder is L (mm), and the current of the lamp is set to 1 (A). When L/I (mm/A) is 0.17 or more, at least one of tin, antimony, gallium, lead, and zinc is enclosed in the inside of the arc tube. (2) Further, the metal of the present invention The halogen lamp lighting device is a metal halide lamp lighting device including a power supply device that supplies electric power to the metal halide lamp, and the power supply device includes a constant power lighting mode and (Electrical effect) (1) It is possible to prevent the metal from entering the sealing portion and prevent corrosion and melting of the foil, so that it can be used for a long time. Maintain metal luminescence while It can be made into a long-life metal halide lamp. (2) For the metal halide lamp lighting device, it is switched by the constant current -9 - 201232600 force lighting mode and the power lower than the above-mentioned constant power lighting mode. The current saving power lighting mode can be used to save power, and the metal halide lamp can be made to perform such power switching, and the illuminance is less likely to be reduced due to the loss of the luminescent material. In the following, an embodiment of the present invention will be described with reference to the embodiments. Fig. 1 is a cross-sectional view showing the basic configuration of a long arc type metal halide lamp according to the present invention, which is cut in the tube axis direction. The light-emitting tube 11 is provided with a sealing portion 11a at both ends thereof, and the molybdenum foil is electrically connected to the electrode 12 in the sealing portion 11a. The light-emitting tube 11 is made of quartz glass excellent in ultraviolet ray permeability. In Fig. 2, the electrode 12 is made of tungsten oxide containing yttrium oxide in tungsten, and the shaft portion of the electrode 12 extends toward the sealing portion, and is connected to the molybdenum foil 54 and the external guiding rod 15. electrode A cylindrical holding member 16 made of quartz glass is disposed around the shaft portion 13. The outer peripheral surface of the holding member 16 is fused and joined to the inner peripheral surface of the arc tube 11, and the electrode shaft portion 13 is held. In the metal halide lamp 10, at least the luminescent material 'in the interior of the arc tube 11 is contained, and at least the iron is contained as the rice material. The iron in the metal halide lamp 10 is used to obtain the main luminescence. The necessary luminescent material is enclosed by ultraviolet rays having a wavelength in the range of 3 〇〇 nm to 400 nm. Further, mercury may be sealed simultaneously with iron. Fig. 2 is an enlarged view showing the sealing portion 1U. In the present invention, - 10 - 201232600 When the length of the quartz glass holding member 16 disposed around the electrode shaft portion 13 is L (mm) and the current I of the halogen lamp is (A), the relationship of L/I (mm/A) is Set to 〇. 1 7 or more. This is because the current density is high when the current 値 of the lamp is large, so the heat in the vicinity of the sealing portion 1 1 a also becomes high, so the influence of heat is relative to the molybdenum foil 14 embedded in the sealing portion 11a. Since it is larger, the length of the holding member 16 is lengthened in accordance with the magnitude of the current, so that the position of the molybdenum foil 14 is kept away from the discharge space S. As a result, the molybdenum foil 14 can be prevented from being heated and melted, and the current supply state can be stably maintained. Further, as described above, the current of the lamp is gradually increased depending on the attenuation of the amount of light irradiated by the lamp, so that the highest arrival current changes as the cumulative lighting time of the lamp passes ( It goes higher, but the input current of the lamp does not always exceed the rated current consumption of the lamp in a higher way. Therefore, in the above relationship of L/I (mm/A), for I ( A ), the length L ( mm ) of the holding member 16 is previously set by using the 额定 of the rated consumption current, no matter what point The state of the lamp to drive the lamp can prevent overheating of the sealing portion and can be stably driven. On the other hand, if the length of the holding member 16 is made longer than the conventional one in such a manner as to satisfy the above relationship L/I 2 0.1 7, the discharge space S and the molybdenum are increased as the holding member 16 is lengthened. The temperature difference of the end portion K of the foil 14 increases the amount of metal halide that permeates into the end portion K of the molybdenum foil 14. In such a case, the amount of luminescence of the metal in the discharge space S is reduced to cause a decrease in illuminance. Here, in order to avoid the loss of such a metal halide, in the invention of the present invention -11 - 201232600, a specific metal having a vapor pressure higher than that of iron is encapsulated, although it cannot directly contribute to luminescence. Specifically, it is one of tin, antimony, gallium, lead, and zinc. These specific metals can be easily enclosed in a state of a suitable halogen compound. Since the specific metal group is a substance having a vapor pressure higher than that of iron, a composite compound is produced by the metal and iron (Fe), and the vapor pressure can be increased in the halogen lamp lighting. As a result, the iron which has previously infiltrated into the sealing portion does not enter the vicinity K of the molybdenum foil 14 of the sealing portion 11a, and can remain in the discharge space S. Here, an example of the ratio of the above-mentioned metal to iron is given. The ratio of atomic ratio of Sn (Sn) to iron (Fe) is 0.25, and the ratio of bis(Bi) to iron (Fe) is Bi/Fe. Is 0.14. Of course, for other metals, it is preferable that the atomic ratio with iron is encapsulated in a suitable range. According to the invention of the present invention, the metal-halogen lamp is lit by the constant power lighting mode and the power-saving lighting mode which is lower than the constant power lighting mode, and the heat distribution state of the arc tube is generated. Significantly uneven, or the luminescent material infiltrates into the interior of the sealing portion to lower the illuminance, or the molybdenum foil embedded in the sealing portion reacts with the metal halide to corrode and impair the conduction state of the power supply portion, or the molybdenum foil All problems such as overheating and dissolution can be eliminated, so that a metal halide lamp that maintains long-term stable illumination can be provided. Hereinafter, the examples of the present invention will be described, but the present invention is not limited to the constitution described below. Various lamps having a structure of -12-201232600 consisting of the metal halide lamps shown in Fig. 3 were produced. The material of the arc tube is quartz glass, and the outer diameter of the tube is 26.1 mm, and the inner diameter is 22.5 mm (wall thickness 1.8 mm). As the luminescent material, iron was sealed at a ratio of l1〇1 lmg/cc, and mercury was sealed at a ratio of 0.17 mg/cc. Iron and tin are enclosed in the same ratio as above. Further, as a metal having a higher vapor pressure than iron, the atomic ratio of tin (Sn) to iron is sealed at a ratio of Sn/Fe = 0.25. The metal halide lamps of Examples 1 to 7 were produced, and the variations thereof were made. The length of the arc tube and the length of the distance between the electrodes are such that the current is 7 (A) to 28 (A), and the length L of the holding member disposed at both ends of the arc tube is 4.8 (mm) to 13.2 (mm). The size of L/I is in the range of 0.17 to 1.89. Further, a metal halide lamp as a comparative example was produced in which any specific metal having a vapor pressure higher than that of iron was not enclosed in the arc tube, and the length L of the holding member was 0.07 to 0.13 with respect to the lamp current. Further, the current I was 15 A to 27 A, the distance between the electrodes was 1100 mm, and the length of the holding member was 2 mm. Each of the metal halide lamps of the above-described Embodiments 1 to 7 and Comparative Example 1 was divided into two stages of rated power consumption and electric power of about 50% or less with respect to the rated power consumption, and the lighting was switched every 30 seconds. As a result, in the metal halide lamp of Comparative Example 1, after the 542 hours of lighting, the molybdenum foil was overheated and melted and not lit. For the metal halide lamps of the other embodiments 1 to 7, after the lighting for 1 000 hours, the state of the molybdenum foil did not change, and the metal halide was not observed. According to the invention described above, The temperature of the molybdenum foil embedded in the sealing portion is maintained low, and the holding member of the shaft portion of the growth electrode is used, and the current increase of -13 to 201232600 with respect to the lamp is 0.17 mm/A or more, thereby increasing the discharge space and The distance of the molybdenum foil can avoid the problem of the foil being melted, and by lowering the vicinity of the molybdenum foil, the metal halide in the discharge space becomes more likely to penetrate, but for the iron as the main luminescent substance By encapsulating a specific metal having a higher vapor pressure, the specific metal to be encapsulated and iron (Fe) form a composite compound to increase the vapor pressure, and as a result, the metal halide can be stably retained in the discharge space. By implementing such a configuration, it is possible to make a strong metal halide lamp for intermittently lighting operations of high input and low input, and on the other hand, when used for a long time, as a further The problem is that the electrode is stretched under intermittent lighting, which causes a problem that the molybdenum foil and the electrode are joined off. With such a problem, by increasing the number of molybdenum foils embedded in the sealing portion to two or more, the strength of the welded portion can be increased, and a longer-life metal halide lamp can be produced. Further, the present invention is of course not limited to the above-described embodiments and examples, and can be appropriately modified. For example, in the above embodiment, mercury is sealed as a luminescent material simultaneously with iron, but it may be carried out only by iron. When mercury is not enclosed, the same current 値 as when mercury is enclosed can be obtained by increasing the amount of the rare gas enclosed or reducing the diameter of the arc tube. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a cross-sectional view showing the direction of the tube axis of the metal halide lamp in the present case -14- 201232600 Fig. 2 is an enlarged view showing the main part. Fig. 3 is a graph summarizing the lamp of the embodiment and the lamp 1/3 of the comparative example. Fig. 4 is a view for explaining a light irradiation device in the manufacture of a liquid crystal panel. Fig. 5 is a view showing the constitution of a prior art metal halide lamp. [Description of main component symbols] 10 : Metal halide lamp 11 : Light-emitting tube 11a : Sealing portion 12 : Electrode 13 : Electrode shaft portion 1 4 : Molybdenum foil 15 : External guiding rod 16 : Electrode shaft portion holding member S : Discharge space K : Molybdenum foil electrode side end -15-