JP2004047243A

JP2004047243A - High-pressure discharge lamp with heat wire and mounting method of heat wire

Info

Publication number: JP2004047243A
Application number: JP2002202278A
Authority: JP
Inventors: Kyoichi Sakugi; 柵　木　教　一; Akira Ogawara; 大河原　　　亮; Sumio Uehara; 上　原　純　夫; Tadashi Omuro; 大　室　　　正; Yoshio Nishizawa; 西　澤　義　男; Tsuguo Sekiguchi; 関　口　嗣　夫
Original assignee: Iwasaki Denki KK
Current assignee: Iwasaki Denki KK
Priority date: 2002-07-11
Filing date: 2002-07-11
Publication date: 2004-02-12
Anticipated expiration: 2022-07-11
Also published as: JP3969225B2

Abstract

<P>PROBLEM TO BE SOLVED: To improve heating efficiency of a luminous part by a heat wire and heighten its heating velocity without lowering of a light volume of a lamp due to the light emitted from the luminous part shielded by the heat wire, by devising how to wind or mount the heat wire spirally wound and mounted on the surface of the luminous tube of a high-pressure discharge lamp in order to heat the luminous part. <P>SOLUTION: The heat wire 4 spirally wound and mounted on the surface of the luminous tube 2 of the high-pressure discharge lamp 1 has its part thickly wound from both sides of the luminous tube 3 where sealed parts 5R, 5L are formed to a part of a swollen face 7 of the luminous tube 3. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、発光管の表面に発光部を加熱するための電熱線がスパイラルに巻かれて取り付けられている電熱線付き高圧放電ランプとその電熱線の取付方法に関する。
【０００２】
【従来の技術】
液晶プロジェクタや投射型液晶ディスプレイ装置等のバックライトは、矩形状のスクリーンに対して充分な輝度、効率及び演色性を以って均一に画像を投射することが要求されるため、その光源として、一対の主電極が対向して配置される発光管の発光部内に水銀や金属ハロゲン化物を封入した高圧放電ランプが用いられている。そして近時は、その光源の小型化、点光源化をより一層推進することが求められている。
【０００３】これらの要求に鑑み、金属ハロゲン化物を封入した高圧放電ランプに代わって、０．１５ｍｇ／ｍｍ^３以上の水銀を封入してランプの安定点灯時における水銀蒸気圧が１００気圧を超える超高圧水銀ランプと称する高圧放電ランプが提案されている（特開平２−１４８５６１号公報、特開平６−５２８３０号公報）。
【０００４】この種のランプは、高輝度・高効率・高演色性を実現するために、ランプの安定点灯時における発光部内の水銀蒸気圧を１００気圧以上に高めることにより、主電極間に生ずるアークの径方向の拡がりを抑えて光出力を向上させるようにしたもので、その発光管のシール部は、耐圧性を高めるために排気用の細管を設けない所謂溶封タイプとし、また、発光部の肉厚は、自動車の前照灯等に用いる高圧放電ランプのそれに比べて約３倍の２ｍｍ前後としている。
【０００５】しかし、このように肉厚が大きい発光部は、熱容量が大きくて温まり難いので、ランプの点灯始動時に発光部の内面に溜まっている液滴状の水銀が温められて水銀蒸気となり、その蒸気分圧が上昇してランプの光出力が立ち上がるまでにかなりの時間を要し、例えば１５０Ｗ程度のランプでは、実に約６０秒もの時間を要する。
【０００６】そのため、この種のランプをバックライトとする液晶プロジェクタや投射型液晶ディスプレイ装置は、立ち上がりが遅く、これら装置をプレゼンテーションなどに使用したときに、スクリーンが画像を投射するに充分な明るさに達するまでの待ち時間が長いという問題があった。
【０００７】この立ち上がりの遅さを改善するために、発光管の球状に膨れた発光部を跨ぐようにしてその両側のシール部にスパイラルに巻かれて取り付けられた電熱線で成るヒータによって、ランプの点灯始動前に発光部の表面温度を予め１００℃以上に加熱する手段が提案されている（特開２００１−２６６７９７号公報）。
【０００８】
【発明が解決しようとする課題】
しかしながら、ランプは、いつ点灯始動されるか分からないので、点灯始動前に発光部を予熱しようとすれば、その予熱を行うヒータは、ランプを点灯しないときも常時通電状態にしておかなければならないので、電力消費量が著しく嵩むという問題がある。また、モバイル系と称される携帯型のディスプレイ装置などは、バックライトとなるランプの発光管にヒータを設けたとしても、該装置を持ち運ぶ際は、そのヒータに通電して発光管の発光部を予熱することができないため、持ち運んで直ぐ使用する場合はランプの光出力の立ち上がりが遅くなってしまう。
【０００９】また、近時は、ランプの光学的効率を高めるうえで、ランプ電力を変更せずにショートアーク化することが望まれており、そのためには、発光部の大きさや形状を変えずに、その発光部内に対向して配置される主電極間の距離を狭めることによってアーク長を短くせざるを得ないが、主電極間の距離を狭めると、該主電極でその主電極間の放電による発光が遮られるシャドウ・ゾーンの範囲が大きくなって、発光部の内面における温度差が大きくなり、シャドウ・ゾーンの中心に位置する各主電極の固定箇所近傍における発光部の内面温度は、従来のアーク長の長いものに比べて著しく低温となる。
【００１０】すなわち、図４は、同一の大きさ及び形状を有する発光管４０の発光部４１内に対向して配置された主電極４２Ｒ、４２Ｌ間の距離が異なるものを対比して示すもので、同図（ａ）の如く主電極４２Ｒ、４２Ｌ間の距離が広くてアーク長が長いものは、主電極４２Ｒ、４２Ｌによってその主電極間の放電による発光が遮られるシャドウ・ゾーン４３の範囲が比較的小さいのに対し、同図（ｂ）の如く主電極４２Ｒ、４２Ｌ間の距離を狭めてアーク長を短くしたものは、そのシャドウ・ゾーン４３の範囲が大きい。
【００１１】このため、図４（ｂ）の発光部４１は、シャドウ・ゾーン４３の中心に位置する各主電極４２Ｒ、４２Ｌの固定箇所近傍における内面の温度が他に比べて著しく低くなり、ランプが安定点灯状態にあるときも、その内面に未蒸発の水銀が溜まりやすい。したがって、発光部４１の内部に０．１５ｍｇ／ｍｍ^３以上の水銀を封入しても、その水銀量に見合った十分な蒸気分圧を得ることができず、安定点灯時のランプ電圧は規格範囲よりも著しく低くなり、ランプ電流は規格範囲よりも大きな値となるので、主電極４２Ｒ、４２Ｌの損耗が早まり、その電極材であるタングステンの蒸発飛散による発光部４１内面の黒化が早期に生じて、ランプ寿命が損なわれるおそれがある。
【００１２】また、発光部４１の内面に未蒸発の水銀が溜まるような低温部分があると、ハロゲン化合物によって黒化を防止するハロゲンサイクルが活発に行われず、そのハロゲンサイクルに異常を来して早期に黒化を生ずる原因となる。
【００１３】また、定格電力未満の低電力でランプを点灯させる調光点灯を行なう場合も、発光部の内面に著しく温度の低い部分があると、水銀の未蒸発によるランプ電圧の低下や光色不良、不安定な放電等を生ずるおそれがある。
【００１４】上記のような問題点に鑑みて、本発明者らは、高圧放電ランプの発光管を加熱するヒータの通電量をコントロールすることにより、発光管をランプの点灯始動前にヒータで予熱せずに、点灯始動時又は始動後にヒータで加熱開始しても、予熱する場合と同等もしくはそれ以上に光出力の立ち上がりを速めることができる発明を提案し（特願２００２−１６８３７３号）、更に、高圧放電ランプが安定点灯状態にあるときにその発光部の内面における最低温度を未蒸発の水銀が溜まらない程度の温度に保持するヒータを設けることにより、ランプのアーク長を短くした場合や、調光点灯を行なう場合に、発光管の発光部内に封入された水銀の未蒸発によるランプ電圧の低下や光色不良等が生じないようにする発明も提案した（特願２００２−１８４７９５号）。
【００１５】しかしながら、上記ヒータは、発光管の発光部を加熱するためのものであるが、そのヒータを成す電熱線が、特開２００１−２６６７９７号公報に図示された如く、球状に膨れた発光部を跨ぐようにしてその両側のシール部にスパイラルに巻かれて取り付けられている場合は、該電熱線から発せられる熱がシール部から発光部へ伝わるまでに時間が掛かるので、発光部の加熱速度が遅くなり、また、その熱がシール部に奪われるので発光部の加熱効率が良くないという問題がある。
【００１６】そこで本発明は、発光管の表面にスパイラルに巻いて取り付ける電熱線の巻き方や取付け方を工夫して、発光部の加熱速度を速めると同時にその加熱効率を高めることを技術的課題としている。
【００１７】
【課題を解決するための手段】
上記の課題を解決するために、請求項１の発明は、球状に膨れた発光部に一対の主電極が対向して配置され、その発光部の両側に前記各主電極を埋設して固定した一対のシール部が形成された発光管の表面に、前記発光部を加熱するための電熱線がスパイラルに巻かれて取り付けられた電熱線付き高圧放電ランプにおいて、前記電熱線が、前記発光部の両側から該発光部の膨れ面の一部にかけて密巻きにされていることを特徴とする。
【００１８】本発明によれば、球状に膨れた発光部の膨れ面の一部に電熱線が密巻きにされているので、その電熱線の熱が発光部に直接伝わり、発光部を速やかに加熱することができると同時に、発光部の加熱効率も高められる。また、シール部が形成された発光部の両側は、ランプの安定点灯状態における内面の温度が最も低い部分であり、短アーク化されたランプの場合は、未蒸発の水銀が溜まりやすい部分となるが、本発明によれば、その低温部分に対して電熱線の熱が効率良く集中的に給与されるので、その部分を未蒸発の水銀が溜まらない程度の温度に確実に加熱保持することができると同時に、その加熱に要する電力も非常に少なくて済む。更に、発光部の両側は、発光部内に対向して配置された一対の主電極によってその主電極間の放電による発光が遮られるシャドウ・ゾーンとなるので、該発光部の両側からその膨れ面の一部にかけて密巻きにされた電熱線がランプの光を遮って光量を低下させるおそれも少ない。
【００１９】次に、上記の如く球状に膨れた発光部の両側からその膨れ面の一部にかけて電熱線を密巻きにする加工を簡易迅速化するために、電熱線の線材を予めコイルに成形してこれを発光部の膨れ面に押し当てるだけで、その膨れ面に密巻きにされた状態となるように工夫したのが、請求項９の発明に係る電熱線の取付方法である。
【００２０】すなわち、請求項９の発明は、球状に膨れた発光部に一対の主電極が対向して配置され、その発光部の両側に前記各主電極を埋設して固定した一対のシール部が形成された高圧放電ランプの発光管の表面に、前記発光部を加熱するための電熱線をスパイラルに巻いて取り付ける電熱線の取付方法であって、前記電熱線の線材となる一対のコイルを前記シール部の一方と他方に振り分けて巻装させ、両コイルを夫々前記発光部に押し当てて押圧することにより、両コイルの先端部側を前記発光部の膨れ面に沿わせて拡径させ、その拡径部を前記発光部の膨れ面に密着させた状態で、両コイルの後端部側を前記各シール部に固定すると共に、両コイルの先端同士を前記発光部の中央側で互いに結線することを特徴とする。
【００２１】本発明によれば、電熱線の線材となる一対のコイルを各シール部に巻装させて、両コイルを発光部に押し当てて押圧するだけで、該発光部の両側からその膨れ面の一部にかけて一対の線材が密巻きにされた状態とすることができる。そして、その線材の先端同士を発光部の中央側で結線すると共に、その線材の後端部側を各々シール部に固定することにより、発光部の両側からその膨れ面の一部にかけて密巻きにされて取り付けられた１本の電熱線となる
【００２２】
【発明の実施の形態】
以下、本発明の実施形態を図面によって具体的に説明する。
図１は本発明による電熱線付き高圧放電ランプの一例を示す断面図、図２はその要部の外観図、図３は電熱線の取付方法を示す図である。
【００２３】本例の高圧放電ランプは、例えばアーク長を従来の１．５ｍｍに比べて著しく短い０．８ｍｍとした１５０Ｗの超高圧水銀ランプ１であって、その発光管２に、球状に膨れた発光部３を加熱するための電熱線４が、発光部３の片側からその反対側にかけてスパイラルに巻かれて取り付けられている。発光部３は、約６０ｍｍ^３程度の内容積を有し、その内部には、該発光部３の両側に形成されたシール部５Ｒ、５Ｌに埋設して固定された一対の主電極６Ｒ、６Ｌが互いに対向して配置されると共に、水銀が約１２ｍｇ、点灯始動用補助ガスとなるアルゴンが約２０ｋＰａ（常温時）封入されている。
【００２４】そして、電熱線４は、球状に膨れた発光部３の両側から該発光部３の膨れ面７の一部にかけて密巻きにされている。なお、電熱線４が発光部３の膨れ面７に密巻きにされる範囲は、ランプの光量を極力低下させないようにするため、主電極６Ｒ、６Ｌ間の放電による発光がその主電極によって遮られるシャドウ・ゾーン（図４（ｂ）のシャドウ・ゾーン４３参照）の略範囲内に選定されている。
【００２５】なお、電熱線４は、発光部３の片側から漸次膨れが大きくなる中央に向かって密巻きに巻くことはできるが、その中央から漸次膨れが小さくなる反対側に向かって密巻きに巻くのは非常に困難である。すなわち、電熱線４を発光部３の片側の膨れ面７から反対側の膨れ面７へと連続して密巻きに巻いて行くことは非常に難しい。そこで、電熱線４は、発光部３の片側からその膨れ面７の一部にかけて密巻きにする線材４Ｒと、該発光部３の反対側からその膨れ面７の一部にかけて密巻きにする線材４Ｌとで形成して、両線材４Ｒ、４Ｌの端末同士を発光部３の中央側で互いに結線させることにより、発光部３の片側からその反対側にかけてスパイラルに巻かれて取り付けられた一本の電熱線を成すようにしている。
【００２６】しかし、発光部３の両側からその膨れ面７の一部にかけて各線材４Ｒ、４Ｌを密巻きに巻いて行くことは技術的に可能であっても、膨れ面７は非常に滑りやすいので、その表面に線材４Ｒ、４Ｌを密着させて均整に密巻きするには非常に高度な加工技術が必要となり、加工装置の開発費も著しく嵩むことが予想されると共に、密巻きにした線材４Ｒ、４Ｌは膨れ面７に接着剤等で固定しなければ巻き解けるおそれがある。そこで、線材４Ｒ、４Ｌは、発光部３の膨れ面７に簡単且つ迅速に密巻きすることができ、接着剤等で膨れ面７に固定しなくても巻き解けることなく密巻き状態を保持できるようにするため、予めシール部５Ｒ、５Ｌの表面に沿ってスライド可能に巻装させるコイルに成形されている。
【００２７】そして、その線材４Ｒ、４Ｌとなる一対のコイルＣ、Ｃを図３の如くシール部５Ｒ、５Ｌの一方と他方に振り分けて巻装させ、両コイルＣ、Ｃを各々矢印方向にスライドさせて発光部３の両側に押し当てると同時に、その矢印方向に押圧することにより、両コイルＣ、Ｃの先端部側を図１の如く発光部３の膨れ面７に沿わせて拡径させ、その拡径部を膨れ面７に密着させた状態で、図２の如く、両コイルＣ、Ｃの後端部側をシール部５Ｒ、５Ｌにステー８で固定すると共に、両コイルＣ、Ｃの先端同士を発光部３の中央側で結線して一本の電熱線４とする。
【００２８】このようにすれば、発光部３の滑りやすい膨れ面７に線材４Ｒ、４Ｌを密巻きに巻いて行くという高度で難しい加工は不要であり、線材４Ｒ、４Ｌを予めコイルに成形してこれを発光部３に押し当てて押圧するだけの極めて簡単な加工によって膨れ面７に密巻きにされた状態とすることができる。しかも、コイルに成形した線材４Ｒ、４Ｌは、その先端同士を結線し、各々の後端部側をステー８で固定してシール部５Ｒ、５Ｌ側に擦り動かないようにしておけば、膨れ面７を滑動して巻き解けるおそれがないので、その膨れ面７における密巻き状態を確実に保持することができ、電熱線４全体に巻き緩みが生ずることを阻止できる。
【００２９】なお、シール部５Ｒ、５Ｌに巻装させるコイルＣ、Ｃは、そのコイルＣに成形した状態でシール部５Ｒ、５Ｌの端末から該シール部に外嵌して巻装させるか、あるいはシール部５Ｒ、５Ｌの表面に線材４Ｒ、４Ｌをワインダ等で直接コイル状に巻き付けてコイルＣに成形する場合であってもよい。また、コイルＣ、Ｃは、図３の如くコイルピッチに隙間がなく線材４Ｒ、４Ｌが密巻き状態になっているものに限らず、コイルピッチに隙間があって線材４Ｒ、４Ｌが疎巻き状態になっているものであってもよく、後者の場合も、発光部３に押し当てて押圧する際にコイルピッチに隙間のない圧縮状態となって、線材４Ｒ、４Ｌが必然的に密巻き状態となる。
【００３０】また、電熱線４は発光部３の片側からその発光部を跨いで反対側へスパイラルに巻かれて取り付けられるので、その電熱線４を成す線材４Ｒ、４Ｌの巻き方向は同じである。したがって、両線材４Ｒ、４Ｌの端末同士を付き合わせてピンポイント溶接等により結線させることもできるが、図２の如く両線材４Ｒ、４Ｌを巻き締める方向にその端末同士を捩り合せて結線させることにより、電熱線４全体に巻き緩みが生ずることを確実に防止することができる。なお、その端末同士を捩り合せて結線した部分を溶接しておけば、結線部分が解けるおそれもない。
【００３１】また、電熱線４は、例えば鉄、クロム、アルミニウムを含む合金で線径約０．２９ｍｍに製出された線材４Ｒ、４Ｌで成ると共に、密巻きにされた部分が短絡しないようにするため、その線材４Ｒ、４Ｌを予め加熱処理して表面に電気絶縁性を有する酸化皮膜が形成されている。この酸化皮膜は、２Ｖ程度以上の絶縁耐圧を有するので、電熱線４に通電する電圧値を２Ｖ程度に抑え、電流値を大きくして、発光部３の加熱に必要な通電量を得るようにすれば、電熱線４が密巻きにされた部分に短絡が生ずることを防止することができる。
【００３２】なお、シール部５Ｒ、５Ｌは、その表面を傷付けると破裂を生ずる危険性があるので、ステー８は、シール部５Ｒ、５Ｌの端末から該シール部にスライド可能に外嵌するリングに成形され、そのリングの内側と各シール部５Ｒ、５Ｌの表面との間に生する隙間に、各線材４Ｒ、４Ｌの後端部側の端末を挿通させた状態で、割リング状のバネ板（図示せず）を圧入し、それにより生ずる楔効果で、ステー８を各シール部５Ｒ、５Ｌの表面に緊着させると同時に、そのステー８で各線材４Ｒ、４Ｌの後端部側を固定するようになっている。
【００３３】また、ステー８は、発光管２と同種素材の石英管や、ムライト、アルミナなどの耐熱酸化物で成る中空管を幅２〜３ｍｍ程度にカットしたカットピース等を用いており、該ステー８で電熱線４の両端側を発光部３の両側に押し当てるようにして固定すれば、発光部３の加熱効率が著しく向上する。
【００３４】
【発明の効果】
以上のように、本発明によれば、高圧放電ランプの発光管の表面に取り付ける電熱線が、シール部が形成された発光部の両側からその膨れ面の一部にかけて密巻きにされているので、発光部の加熱効率が非常に良く、発光部の加熱速度も速めるられると同時に、その電熱線がランプの光を遮って光量を低下させるおそれも少ないという優れた効果がある。
【図面の簡単な説明】
【図１】本発明による電熱線付き高圧放電ランプの一例を示す断面図
【図２】図１に示す高圧放電ランプの要部の外観図
【図３】本発明による電熱線の取付方法を示す図
【図４】本発明が解決しようとする課題を説明するための図
【符号の説明】
１………………ランプ
２………………発光管
３………………発光部
４………………電熱線
４Ｒ……………線材
４Ｌ……………線材
５Ｒ……………シール部
５Ｌ……………シール部
６Ｒ……………主電極
６Ｌ……………主電極
７………………膨れ面
８………………ステー[0001]
TECHNICAL FIELD OF THE INVENTION
TECHNICAL FIELD The present invention relates to a high-pressure discharge lamp with a heating wire in which a heating wire for heating a light emitting section is mounted on the surface of an arc tube in a spiral manner and a method of mounting the heating wire.
[0002]
[Prior art]
Backlights such as liquid crystal projectors and projection-type liquid crystal display devices are required to uniformly project an image on a rectangular screen with sufficient luminance, efficiency, and color rendering properties. A high-pressure discharge lamp in which mercury or a metal halide is sealed in a light emitting portion of an arc tube in which a pair of main electrodes are arranged to face each other is used. Recently, there has been a demand for further downsizing of the light source and the use of a point light source.
In view of these requirements, instead of a high-pressure discharge lamp filled with a metal halide, 0.15 mg / mm ³ or more of mercury is charged and the mercury vapor pressure during stable operation of the lamp exceeds 100 atm. A high-pressure discharge lamp called a high-pressure mercury lamp has been proposed (JP-A-2-148561, JP-A-6-52830).
In order to realize high brightness, high efficiency and high color rendering, this kind of lamp is generated between the main electrodes by increasing the mercury vapor pressure in the light emitting portion to 100 atm or more during stable operation of the lamp. The light output is improved by suppressing the radial expansion of the arc, and the seal portion of the arc tube is a so-called sealed type that does not have a thin tube for exhaust to increase the pressure resistance. The thickness of the portion is about 2 mm, which is about three times as large as that of a high-pressure discharge lamp used for a headlight of an automobile or the like.
However, since the light emitting portion having such a large thickness has a large heat capacity and is difficult to be heated, the mercury in the form of droplets accumulated on the inner surface of the light emitting portion when the lamp is started to be turned into mercury vapor, It takes a considerable amount of time for the light output of the lamp to rise due to the increase in the vapor partial pressure. For example, a lamp of about 150 W requires about 60 seconds.
For this reason, a liquid crystal projector or a projection type liquid crystal display device using such a lamp as a backlight has a slow start-up, and when the device is used for a presentation or the like, the screen has sufficient brightness to project an image. There is a problem that the waiting time until reaching is long.
In order to improve the delay of the rise, the lamp is heated by a heater composed of a heating wire spirally wound and attached to the seal portions on both sides of the light-emitting portion of the arc tube so as to straddle the spherically expanded light-emitting portion. Means for heating the surface temperature of the light emitting unit to 100 ° C. or more before starting the lighting of (1) has been proposed (Japanese Patent Application Laid-Open No. 2001-266797).
[0008]
[Problems to be solved by the invention]
However, since it is not known when the lamp is started to be turned on, if the light-emitting unit is to be preheated before the start of the lighting, the heater that performs the preheating must be always energized even when the lamp is not turned on. Therefore, there is a problem that power consumption is significantly increased. In a portable display device called a mobile system, even if a heater is provided in an arc tube of a lamp serving as a backlight, when carrying the device, the heater is energized to emit light from the arc tube. Cannot be preheated, so that when used immediately after being carried, the light output of the lamp rises slowly.
In recent years, in order to increase the optical efficiency of the lamp, it has been desired to make the arc short without changing the power of the lamp. In addition, the arc length must be shortened by reducing the distance between the main electrodes disposed to face each other in the light emitting portion, but when the distance between the main electrodes is reduced, the distance between the main electrodes is reduced by the main electrodes. The range of the shadow zone where light emission due to discharge is blocked increases, the temperature difference on the inner surface of the light emitting unit increases, and the inner surface temperature of the light emitting unit near the fixed point of each main electrode located at the center of the shadow zone is: The temperature is significantly lower than that of a conventional arc having a long arc length.
That is, FIG. 4 shows a case where the distance between the main electrodes 42R and 42L arranged opposite to each other in the light emitting portion 41 of the arc tube 40 having the same size and shape is different from each other. In the case where the distance between the main electrodes 42R and 42L is large and the arc length is long as shown in FIG. 3A, the shadow zone 43 in which light emission due to discharge between the main electrodes is blocked by the main electrodes 42R and 42L. In contrast to the case where the arc length is shortened by reducing the distance between the main electrodes 42R and 42L as shown in FIG. 3B, the range of the shadow zone 43 is large.
For this reason, in the light emitting section 41 of FIG. 4B, the temperature of the inner surface in the vicinity of the fixed portion of each of the main electrodes 42R and 42L located at the center of the shadow zone 43 becomes extremely low as compared with the others, and the lamp Even when is in a stable lighting state, unevaporated mercury easily accumulates on its inner surface. Therefore, even if mercury of 0.15 mg / mm ³ or more is sealed in the light emitting part 41, a sufficient vapor partial pressure corresponding to the amount of mercury cannot be obtained, and the lamp voltage at the time of stable lighting is within the standard range. And the lamp current becomes larger than the standard range, the wear of the main electrodes 42R and 42L is accelerated, and the blackening of the inner surface of the light emitting portion 41 due to the evaporation and scattering of tungsten as the electrode material occurs early. As a result, the lamp life may be shortened.
Further, if there is a low-temperature portion where unevaporated mercury is accumulated on the inner surface of the light emitting section 41, the halogen cycle for preventing blackening by the halogen compound is not actively performed, and the halogen cycle becomes abnormal. It causes blackening early.
[0013] Also, in the case of dimming lighting in which the lamp is lit with a low power less than the rated power, if there is a remarkably low temperature portion on the inner surface of the light emitting portion, the lamp voltage is reduced due to the non-evaporation of mercury and the light color is reduced. There is a possibility that defective or unstable discharge may occur.
In view of the above problems, the present inventors controlled the amount of electricity supplied to the heater for heating the arc tube of the high-pressure discharge lamp, thereby preheating the arc tube with a heater before starting the lamp lighting. Without this, even if heating is started by a heater at the start of lighting or after starting, an invention capable of accelerating the rise of light output to be equal to or more than the case of preheating is proposed (Japanese Patent Application No. 2002-168373). When the arc length of the lamp is shortened by providing a heater that keeps the minimum temperature on the inner surface of the light emitting portion at a temperature at which unevaporated mercury does not accumulate when the high-pressure discharge lamp is in a stable lighting state, An invention has also been proposed for preventing dimming of mercury sealed in the light emitting portion of the arc tube from causing a decrease in lamp voltage and a defective light color when dimming lighting is performed (Japanese Patent Application No. 002-184795).
However, the above-mentioned heater is for heating the light-emitting portion of the arc tube, and the heating wire constituting the heater emits light in a spherically expanded manner as shown in JP-A-2001-266797. In the case where the heat is emitted from the heating wire and the heat is transmitted from the seal portion to the light emitting portion, it takes time to heat the light emitting portion. There is a problem in that the heating speed of the light emitting portion is not good because the speed is reduced and the heat is taken by the seal portion.
Therefore, the present invention has a technical problem of improving the heating rate of the light emitting portion and increasing the heating efficiency by devising a method of winding and attaching a heating wire to be spirally wound around the surface of the arc tube. And
[0017]
[Means for Solving the Problems]
In order to solve the above problem, according to the invention of claim 1, a pair of main electrodes are arranged so as to face a bulging light emitting portion, and the main electrodes are embedded and fixed on both sides of the light emitting portion. A high-pressure discharge lamp with a heating wire, on which a heating wire for heating the light-emitting portion is spirally wound and attached to the surface of the light-emitting tube on which the pair of seal portions is formed, wherein the heating wire is formed of the light-emitting portion. It is characterized by being tightly wound from both sides to a part of the swollen surface of the light emitting portion.
According to the present invention, since the heating wire is tightly wound on a part of the swelling surface of the bulging light emitting portion, the heat of the heating wire is directly transmitted to the light emitting portion, and the light emitting portion is quickly moved. At the same time as heating can be performed, the heating efficiency of the light emitting unit can be increased. In addition, both sides of the light emitting portion where the seal portion is formed are portions where the temperature of the inner surface in the stable lighting state of the lamp is the lowest, and in the case of a short arc lamp, unevaporated mercury is likely to accumulate. However, according to the present invention, since the heat of the heating wire is efficiently and intensively supplied to the low-temperature portion, it is possible to reliably heat and maintain the portion at a temperature at which unevaporated mercury does not accumulate. At the same time, the power required for the heating is very low. Furthermore, since the two sides of the light emitting portion are shadow zones in which light emission due to discharge between the main electrodes is blocked by a pair of main electrodes disposed to face each other in the light emitting portion, the swollen surface of the swollen surface from both sides of the light emitting portion. There is little possibility that the heating wire that is tightly wound around a part of the lamp blocks the light of the lamp and reduces the light amount.
Next, in order to simplify and speed up the process of densely winding the heating wire from both sides of the light emitting portion swelled as described above to a part of the swelling surface, a wire of the heating wire is previously formed into a coil. The heating wire mounting method according to the ninth aspect of the present invention is devised so that the swelling surface is tightly wound by merely pressing the swelling surface against the swelling surface.
That is, according to the present invention, a pair of main electrodes are arranged to face a light-emitting portion bulging in a spherical shape, and the main electrodes are embedded and fixed on both sides of the light-emitting portion. A method of attaching a heating wire for heating the light emitting portion in a spiral manner on the surface of the arc tube of the high-pressure discharge lamp formed with a pair of coils serving as a wire of the heating wire. It is distributed and wound around one and the other of the seal portion, and both coils are pressed against the light emitting portion, respectively, so that the leading ends of both coils are expanded along the bulging surface of the light emitting portion. In a state where the enlarged diameter portion is in close contact with the bulging surface of the light emitting portion, the rear end portions of both coils are fixed to the respective seal portions, and the leading ends of both coils are mutually attached at the center side of the light emitting portion. It is characterized by connection.
According to the present invention, a pair of coils serving as a wire of a heating wire is wound around each seal portion, and both coils are pressed against the light emitting portion to swell from both sides of the light emitting portion. A pair of wires can be tightly wound over a part of the surface. Then, the front ends of the wires are connected at the center of the light emitting portion, and the rear ends of the wires are fixed to the seal portions, so that the wire is tightly wound from both sides of the light emitting portion to a part of the swollen surface. And becomes one attached heating wire.
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.
FIG. 1 is a cross-sectional view showing an example of a high-pressure discharge lamp with a heating wire according to the present invention, FIG. 2 is an external view of a main part thereof, and FIG.
The high-pressure discharge lamp of this embodiment is, for example, a 150 W ultra-high pressure mercury lamp 1 whose arc length is 0.8 mm, which is much shorter than the conventional 1.5 mm. A heating wire 4 for heating the light emitting unit 3 is attached by being spirally wound from one side of the light emitting unit 3 to the opposite side. The light emitting section 3 has an internal volume of about 60 mm ^3, and a pair of main electrodes 6 R, 6 L embedded and fixed in seal portions 5 R, 5 L formed on both sides of the light emitting section 3. Are arranged to face each other, and about 12 mg of mercury and about 20 kPa (at room temperature) of argon as an auxiliary gas for starting lighting are sealed.
The heating wire 4 is tightly wound from both sides of the bulging light emitting unit 3 to a part of the bulging surface 7 of the light emitting unit 3. The range in which the heating wire 4 is closely wound around the bulging surface 7 of the light emitting section 3 is such that the light emission due to the discharge between the main electrodes 6R and 6L is blocked by the main electrode in order to minimize the light quantity of the lamp. The shadow zone is selected substantially within the range of the shadow zone (see shadow zone 43 in FIG. 4B).
The heating wire 4 can be wound tightly from one side of the light emitting portion 3 toward the center where the swelling gradually increases, but from the center toward the opposite side where the swelling gradually decreases. It is very difficult to roll. That is, it is very difficult to continuously and densely wind the heating wire 4 from the swelling surface 7 on one side of the light emitting unit 3 to the swelling surface 7 on the opposite side. Therefore, the heating wire 4 is tightly wound from one side of the light emitting part 3 to a part of the swelling surface 7 and the wire is tightly wound from the opposite side of the light emitting part 3 to a part of the swelling surface 7. 4L, and the terminals of the two wires 4R and 4L are connected to each other at the center of the light emitting unit 3 so that one end of the light emitting unit 3 is wound and attached spirally from one side to the opposite side. Makes a heating wire.
However, although it is technically possible to tightly wind the wires 4R and 4L from both sides of the light emitting portion 3 to a part of the swelling surface 7, the swelling surface 7 is very slippery. Therefore, in order to bring the wires 4R and 4L into close contact with each other and to uniformly and closely wind them, a very advanced processing technique is required, and it is expected that the development cost of the processing apparatus will be significantly increased. 4R and 4L may be unwound unless fixed to the swollen surface 7 with an adhesive or the like. Therefore, the wires 4R and 4L can be easily and quickly tightly wound around the swelling surface 7 of the light emitting section 3, and can be kept tightly wound without being unwound without being fixed to the swelling surface 7 with an adhesive or the like. For this purpose, the coil is formed in advance so as to be slidably wound along the surfaces of the seal portions 5R and 5L.
Then, as shown in FIG. 3, a pair of coils C, C to be the wires 4R, 4L are distributed and wound around one and the other of the seal portions 5R, 5L, and both coils C, C are slid in the directions of the arrows. At the same time, it is pressed against both sides of the light emitting section 3 and simultaneously pressed in the direction of the arrow, so that the distal ends of both coils C, C are enlarged along the bulging surface 7 of the light emitting section 3 as shown in FIG. 2, the rear end portions of both coils C, C are fixed to the seal portions 5R, 5L with stays 8 while the enlarged diameter portion is in close contact with the swollen surface 7. Are connected at the center of the light emitting section 3 to form one heating wire 4.
In this way, there is no need for a sophisticated and difficult process of densely winding the wires 4R and 4L on the slippery bulging surface 7 of the light emitting portion 3, and the wires 4R and 4L are formed into coils in advance. The bulging surface 7 can be brought into a tightly wound state by a very simple process of pressing and pressing the lever against the light emitting unit 3. In addition, the wire rods 4R and 4L formed into coils are connected to each other at their leading ends, and the rear end portions thereof are fixed with stays 8 so as not to rub against the seal portions 5R and 5L. Since there is no possibility that the heating wire 7 is slid and unwound, the tightly wound state of the swelling surface 7 can be reliably maintained, and the entire heating wire 4 can be prevented from becoming loose.
The coils C, C to be wound around the seal portions 5R, 5L may be wound around the ends of the seal portions 5R, 5L in a state of being formed into the coil C, or The case where the wires 4R and 4L are directly wound around the surfaces of the seal portions 5R and 5L in a coil shape by a winder or the like and formed into a coil C may be employed. Further, the coils C, C are not limited to those in which the wire rods 4R, 4L are tightly wound with no gap in the coil pitch as shown in FIG. In the latter case as well, when pressed against the light emitting unit 3 and pressed, the coil pitch is in a compressed state with no gap, and the wires 4R and 4L are necessarily tightly wound. It becomes.
Since the heating wire 4 is spirally wound from one side of the light emitting portion 3 to the opposite side across the light emitting portion, the wires 4R and 4L constituting the heating wire 4 have the same winding direction. . Therefore, the ends of the two wires 4R and 4L can be connected together by pinpoint welding or the like, but as shown in FIG. 2, the ends of the two wires 4R and 4L are twisted and connected in the direction of winding and tightening. Thereby, loosening of the entire heating wire 4 can be reliably prevented. It should be noted that, if the terminals are twisted together and the connected portions are welded, there is no possibility that the connected portions are unraveled.
The heating wire 4 is made up of wires 4R and 4L made of an alloy containing, for example, iron, chromium, and aluminum to a wire diameter of about 0.29 mm, and the tightly wound portion is not short-circuited. To this end, the wires 4R and 4L are previously heat-treated to form an oxide film having electrical insulation on the surface. Since the oxide film has a withstand voltage of about 2 V or more, the voltage value applied to the heating wire 4 is suppressed to about 2 V, the current value is increased, and the amount of current necessary for heating the light emitting unit 3 is obtained. This can prevent a short circuit from occurring at a portion where the heating wire 4 is closely wound.
Since the seal portions 5R and 5L may be ruptured if their surfaces are damaged, the stay 8 is attached to a ring which is slidably fitted to the seal portions 5R and 5L from the ends of the seal portions. A split ring-shaped spring plate is formed in a state where the terminals at the rear end portions of the wires 4R and 4L are inserted into gaps formed between the inside of the ring and the surfaces of the seal portions 5R and 5L. (Not shown), and the stay 8 is tightly attached to the surface of each of the seal portions 5R and 5L by the wedge effect caused thereby, and at the same time, the rear ends of the wires 4R and 4L are fixed by the stay 8. It is supposed to.
The stay 8 uses a quartz tube made of the same material as the arc tube 2, a cut piece obtained by cutting a hollow tube made of a heat-resistant oxide such as mullite or alumina into a width of about 2 to 3 mm, or the like. If the both ends of the heating wire 4 are pressed against both sides of the light emitting unit 3 by the stay 8, the heating efficiency of the light emitting unit 3 is remarkably improved.
[0034]
【The invention's effect】
As described above, according to the present invention, the heating wire attached to the surface of the arc tube of the high-pressure discharge lamp is tightly wound from both sides of the light-emitting portion where the seal portion is formed to a part of the bulging surface. In addition, there is an excellent effect that the heating efficiency of the light emitting portion is very good, the heating speed of the light emitting portion is increased, and there is little possibility that the heating wire blocks the light of the lamp to reduce the light amount.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an example of a high-pressure discharge lamp with a heating wire according to the present invention. FIG. 2 is an external view of a main part of the high-pressure discharge lamp shown in FIG. 1. FIG. FIG. 4 is a diagram for explaining a problem to be solved by the present invention.
1 ... Lamp 2 ... Emission tube 3 ... Emission part 4 ... Electric heating wire 4R ... Wire 4L ... Wire 5R ... Seal part 5L ... Seal part 6R ... Main electrode 6L ... Main electrode 7 ... Bulging surface 8 ... Stay

Claims

A pair of main electrodes are arranged to face the light-emitting portion bulging in a spherical shape, and the light-emitting tube is provided with a pair of seal portions in which the main electrodes are embedded and fixed on both sides of the light-emitting portion. In a high-pressure discharge lamp equipped with a heating wire, the heating wire for heating the portion is spirally wound and attached, and the heating wire (4) is provided on both sides of the light emitting portion (3). ). A high-pressure discharge lamp with a heating wire, wherein the high-pressure discharge lamp is closely wound around part of).

The heating wire (4) extends from one end of the light emitting portion (3) to a part of its swollen surface (7), and the terminal of the wire (4R) wound tightly, and from the opposite side of the light emitting portion (3). The high-pressure discharge lamp with a heating wire according to claim 1, wherein the ends of the wire (4L) wound tightly around a part of the bulging surface (7) are connected to each other at the center of the light emitting portion (3).

The high-pressure discharge lamp with a heating wire according to claim 2, wherein the terminals of the two wires (4R, 4L) are connected by being twisted in a direction in which both wires are wound.

The high-pressure discharge lamp with a heating wire according to claim 2 or 3, wherein connection portions of the two wires (4R, 4L) are welded.

The high-pressure discharge lamp with a heating wire according to claim 2, wherein the two wires (4R, 4L) are coils (C) wound around the seal portions (5R, 5L) in advance.

The high-pressure discharge lamp with a heating wire according to claim 1, wherein the heating wire (4) is made of a wire having an oxide film having electrical insulation formed on a surface thereof by a heat treatment.

The range in which the heating wire (4) is closely wound around the bulging surface (7) of the light emitting section (3) is a shadow area where light emission due to discharge between the main electrodes (6R, 6L) is blocked by the main electrodes. 7. The high-pressure discharge lamp with a heating wire according to claim 1, wherein the high-pressure discharge lamp is selected within a substantially range of the zone.

A stay (8) is attached to the seal portion (5R, 5L) to prevent the heating wire (4) from rubbing against the seal portion side and to prevent the heating wire (4) from loosening. The high-pressure discharge lamp with a heating wire according to claim 1, 2, 3, 4, 5, 6, or 7.

A surface of a light-emitting tube of a high-pressure discharge lamp in which a pair of main electrodes are arranged so as to face a spherically bulging light-emitting portion, and a pair of seal portions in which the main electrodes are embedded and fixed are formed on both sides of the light-emitting portion. A method of attaching a heating wire for heating the light-emitting portion in a spiral manner, wherein the heating wire is a wire rod (4R, 4L) of the heating wire (4). Are distributed and wound around one and the other of the seal portions (5R, 5L), and both coils (C, C) are pressed against the light emitting portion (3), respectively. ) Is expanded along the swelling surface (7) of the light emitting portion (3), and the expanded portion is brought into close contact with the swelling surface (7) of the light emitting portion (3). The rear ends of both coils (C, C) are fixed to the seal portions (5R, 5L), and Le (C, C) Mounting of the heating wire, characterized in that for connecting each other at the center side of the light emitting portion of tips of (3).