200837802 九、發明說明： 本申請案根據2007年1月24日提出申請之日本特許 申請案第2007- 1 3 9 1 1號並依此主張優先權，在此以參照方 式倂提其全文。 【發明所屬之技術領域】 本發明係有關一種用於製造冷陰極螢光燈以及用於該 冷陰極螢光燈之電極的方法。本發明亦有關一種冷陰極螢 光燈以及一用於該冷陰極螢光燈的電極。本發明尤有關一 # 種製造用於冷陰極螢光燈之用來作爲電極之管狀構件的方 法。 【先前技術】 由於冷陰極螢光燈在尺寸減小、低耗電、壽命長等上 的潛力，因此，近年來，被用來作液晶面板等之背光的情 形大增。冷陰極螢光燈通常具有一對電極彼此相對配置於 一玻璃管內，該玻璃管充塡諸如氬氣之稀有氣體及汞氣， 且其中引線連接於電極的結構。各電極形成爲一具有一封 • 閉端及一敞開端的管狀。此等電極配置成敞開端彼此相 對。當經由引線，將一電壓施加於此等電極間時，電子自 此等電極之一射出，並碰撞汞原子而產生紫外線。藉一形 成於玻璃管表面上的螢光膜將紫外線轉換成可見光，自玻 璃管內部向外發出該可見光。因此，冷陰極螢光燈壽命高 度取決於汞氣之消耗量。 電極通常由鎳製成。一混合物例子係99.7%的鎳、0.1 %的錳、0 · 1 %的鐵以及0.1 %的其他雜質（碳、矽、銅、硫）。 200837802 鎳可含有約〇 · 〇 1 %微量的鈷。以上混合物以重量百分比表 示。當玻璃管中的氬氣等撞擊到鎳時，鎳原子即濺射並散 射。此現象稱爲濺射。散射之鎳原子吸收汞氣以形成汞劑， 藉此減低汞氣的有效量。結果，汞氣被消耗掉，減短冷陰 極螢光燈的壽命。 近年來’爲使冷陰極螢光燈的壽命更長，硏究使用耐 濺射之電極的技術。更具體而言，揭露於世者有包含鉬（Mo) 或鈮（Nb)的管狀電極，其相較於鎳具有低加工功能及高濺 # 射電阻率。例如，請參考日本特許早期公開第2002-3 5 8992 號及2003 - 1 87740號。惟，鉬及鈮不僅昂貴，亦具有高熔 點。因此，爲與引線連接，需要大量的熱來熔化鉬或鈮， 這會造成電極表面的氧化。電極表面的氧化會導致耐濺射 性的劣化，而這有損於高耐濺射性的優點。亦由於鉬等的 熔點與由科瓦鐵鎳鈷合金（Kovar)等製成之引線者間有很 大的不同，因此，有可能由鉬等製成之電極實質上未熔化， 且無法獲得充份的與引線結合力量。 ♦ 日本特許早期公開第200 5 - 1 8 3172號揭示一雙層電極 ，該雙層電極具有一外層以及一設在此外層內部的內層； 外層由鎳等製成，內層由鎢、鉬等製成，並具有高耐濺射 性。外及內層藉由滾軋加工成爲一體，並接著形成呈圓筒 形，俾內層形成一放電表面，而外層則形成一用來與一引 線連接的表面。此結構達成電極與引線間的滿意結合，同 時確保耐濺射性。惟，該技術需要大量具有高耐濺射性， 並因此，在製造成本上較鎳電極更不利。當雙層薄板藉由 200837802 衝壓加工形成呈圓筒形時，亦經常難以有效率地對內層的 材料加工。 日本特許早期公開第2006-2286 1 5號就用來解決此等 問題的技術，揭示一種形成電極之技術，該電極包含作爲 基材之鎳或其合金並包含作爲添加劑，諸如鈦之金屬。由 於諸如鈦之金屬有在鎳晶粒間之間界以氧化物形式偏析的 傾向，因此，於間界的結合力增加，並藉此改進耐濺射性。 揭示於日本特許早期公開第2006-22 86 1 5號之技術的 • 優點在於可使用經濟且具有良好加工性的鎳或鎳合金作爲 基材。惟，管狀電極經常藉由滾軋，由基材之錠塊形成具 有薄板形式的帶，接著藉由衝壓加工，將該板形成呈管狀， 予以製成。於此製程中，電極之表層之晶體間界可能受到 於滾軋及衝壓加工期間內所用的潤滑油污染。在氣密封裝 電極於玻璃管內期間或在作業中作成燈期間內，當電極部 分的溫度昇高時，附著的油可能造成於晶體間界晶粒間結 合力的減小。因此，於該技術中有耐濺射性減低的可能性。 ® 又，於使用鎳或鎳合金作爲基材的電極中，鎳有相較 於自晶粒，更容易自晶體間界濺射傾向。因此，雖有日本 特許早期公開第2006-22 86 1 5號，仍有改進於晶體間界之 耐濺射性的需要。 【發明內容】 本發明之一目的在於提供一種用於製造冷陰極螢光燈 之方法，該冷陰極螢光燈爲高度耐濺射的，容易製造且經 濟，並提供一種製造用於該冷陰極螢光燈的電極之方法。 200837802 本發明之另一目的在.於提供一種冷陰極螢光燈，其爲高度 耐濺射的，容易製造且經濟，並提供一用於該冷陰極螢光 燈的電極。 根據本發明，一種用於製造冷陰極螢光燈之方法包括 以下步驟：由一包含作爲基材之鎳或鎳合金並包含作爲添 加劑之欽、锰、锆或給中至少一種以上元素的材料形成一 管狀構件，該管狀構件於一端封閉，並於另一端具有一開 口；碳化該管狀構件；以及氣密封裝一對碳化管狀構件於 # 一玻璃管中，於其內將管狀電極配置成該等開口相互面 對，其中該玻璃管具有一充塡至少稀有氣體及汞氣的內部 空間，並設有一形成於該玻璃管之內表面上的螢光材料層。 添加於包含作爲基材之鎳或鎳合金之材料的金屬有在 鎳或鎳合金之晶體間界偏析的傾向。因此，藉由進行碳化 步驟，形成添加元素的碳化物於管狀構件之表面附近的晶 體間界。形成於晶體間界的碳化物增加晶粒間的結合力， .並增加晶體間界的表面硬度。結果，改進耐濺射性。在材 • 料形成爲管狀構件的步驟期間內，藉由碳化步驟有效移除 附著於管狀構件的油。因此，減少殘留油所可能造成於晶 體間界之耐濺射性的劣化。 根據本發明之另一例示態樣，包含管狀構件的氮化步 驟以取代碳化步驟。由於形成於晶體間界之氮增加晶粒間 的結合力並增加晶體間界之表面硬度，且由於藉由氮化步 驟去除殘留油，因此，可達到與碳化步驟所可達到者相同 的效果。 200837802 如前述’本發明提供一種用於製造冷陰極螢光燈之方 法，該冷陰極螢光燈爲高度耐濺射的，容易製造且經濟， 以及一種製造用於該冷陰極螢光燈的電極之方法。本發明 亦提供一種冷陰極螢光燈，其爲高度耐濺射的，容易製造 且經濟，以及一用於該冷陰極螢光燈的電極。 參考顯示本發明範例之附圖，本發明之以上及其他目 的、特點及優點將可由以下說明變得明顯。 【實施方式】 φ 首先參考附圖詳細說明本發明之一例示實施例之一冷 陰極螢光燈及一電極。根據本發明，冷陰極螢光燈適於用 來作爲液晶面板之背光。惟，冷陰極螢光燈亦可作其他用 途。第1圖係顯示冷陰極螢光燈之一例示實施例之構造的 示意剖視圖。 冷陰極螢光燈1具有一由硼矽玻璃形成之玻璃管2。 玻璃管2之兩端藉密封玻璃（玻璃珠3)氣密封接。玻璃管2 具有1.5至6.0mm之外徑，且較佳地，具有1.5至5. 0mm之 # 外徑。玻璃管2之材料亦可爲鉛玻璃、鈉玻璃（s〇da glass)、 低鉛玻璃等。 一未顯示之螢光材料層於管之全長形成於玻璃管2之 內表面4上。形成螢光材料層之螢光材料可根據冷陰極螢 光燈1之用途及使用，選自諸如鹵磷酸鹽螢光材料及希土 螢光材料之既有或新穎螢光材料。又，螢光材料層亦可由 藉由混合二種以上螢光材料製備的螢光材料形成。 將一預定量之諸如氬、氙或氖之稀有氣體及一預定量 200837802 之汞氣充塡於玻璃管2由內表面4圍繞的內部空間5內’ 並將內部壓力減至約數十分之一大氣壓力。 一對電極單元6沿縱長方向設在玻璃管2兩端。各電 極單元6由管狀電極7及連結於底部8之引線9構成， 該底部8係管狀電極· 7之封閉端。各電極單元6中的管狀 電極7向內位於與玻璃管2之內部空間5 —端隔一距離 處，俾管狀電極7之一的開口 1 0與另一之開口 1 0相互面 對。將各引線9之一端熔接於對應管狀電極7之底部8， • 另一端則透過玻璃珠3伸出玻璃管2外。引線9由諸如科 瓦鐵鎳鈷合金（Kovar)之導電材料製成。 第2圖係設於冷陰極螢光燈1之電極單元6之放.大立 體圖。構成電極單元6之管狀電極‘ 7具有管狀部分23。管 狀部分23之一端相對於縱長方向設有開口 i 〇，且另一端 以底部8封閉。引線9以端面1 2熔接於管狀電極7之底部 8 〇 管狀電極7包含鎳或鎳合金以作爲基材。主要於管狀 • 電極7之表面附近形成鈦、錳、锆或給之碳化物或氮化物。 碳化物或氮化物雖然亦形成在於鎳晶粒內，惟主要形成於 晶粒間界中。可於鈦、鍤、锆或鉛間包含二種以上元素。 鈦於混合物中的比例以0·009至〇.8wt% (重量百分比）較 佳。鉻及給於混合物中的比例以0 · 〇 5至1 _ 1 w t % (重量百分 比）較佳。猛於混合物中的比例以1 · 1至4 · 〇 w t % (重量百分 比）較佳。各元素於混合物中的上限主要依管狀電極7的可 製造性而疋。右比例1¾於上限，材料即變得過硬而無法藉 -10- 200837802 由衝壓加工形成圓筒形。決定各元素於混合物中的比例下 限，以充份確保高耐濺射性。 一含有作爲主要添加劑之鈦的混合物例子包含99.7% 的鎳、0.05%的鈦，〇. 1 5%的錳以及〇· 1 %的其他雜質（碳、 矽、銅、硫、錳及鐵）。鎳含有相當於約〇 · 〇 1 %微量的鈷。 鈦以鈦之碳化物或鎳-鈦碳化物形式存在。 將參考第3圖說明藉由添加此等金屬改進管狀電極7 之耐濺射性的理由。雖然對添加鈦的情形加以解釋，惟此 φ 解釋同樣適用於添加錳、锆或給的情形。鎳或鎳合金通常 具有多晶結構，且晶粒間界B形成於晶粒G間的界面。由 於晶粒間的結合力小，因此，晶粒間界B容易受到濺射影 響。濺射主要發生於晶粒間界B並逐漸擴展進入晶粒G。 另一方面，添加於鎳之添加劑有於晶粒間界B偏析的 傾向，鈦亦無例外。若鈦於晶粒間界B充份偏析時碳化或 氮化，存在於晶粒間界B之鈦即形成爲鈦的碳化物或氮化 物或鎳-鈦的碳化物或氮化物。此等碳化物或氮化物通常發 # 揮大幅增加晶粒間結合力的功能，並藉此發揮增加材料之 表面硬度的功能。因此，增高耐職射性。上述混合物中元 素的比例下限對應於分配充份量之鈦於晶粒間界B以改進 耐濺射性所需鈦量。 將參考第4圖說明一種製造上述冷陰極螢光燈之方 法。 (步驟S1)首先熔化鎳或鎳合金，接著添加鈦、錳、鉻 或給（此後稱爲〜添加元素〃）。接著’將鎳或鎳合金固化 -11- 200837802 以形成含有添加元素的錠塊。由於如上述，由鎳或鎳合金 形成的基材具有多晶結構，因此，添加元素於晶粒間界偏. 析。雖然添加元素的一部分會與鎳或大氣中所含氧結合， 並以氧化物的形式存在，惟咸認爲並非所有添加元素之原 子氧化，且大多數添加元素未被氧化。 (步驟S 2)以一普通滾軋步驟將錠塊形成爲一薄板（帶） 。接著使薄板接受衝壓加工，並形成爲一管狀構件，其在 一端封閉，並在另一端敞開。於此等步驟中，使用油作爲 φ 潤滑劑。雖然藉由清洗去除油，惟如前述，部分油可能主 要殘留在晶粒間界，並可能造成粒子於晶粒間界的結合力 減小。所獲得管狀構件具有與第1圖及第2圖所示管狀電 極7相同之形狀，惟與管狀電極7之不同點在於其尙未受 到以下說明的碳化或氮化程序。 (步驟S3)接著，將所形成管狀構件碳化。碳化方法包 含固相碳化方法、液相碳化方法、氣相碳化方法、真空電 漿碳化方法等。於固相碳化方法中，於一碳化箱中產生一 # 氧化碳（CO)。CO接著分解於一待處理物之表面上，容許碳 (C)滲入並擴散入該物內。於液相碳化方法中，將一待處理 物浸漬於一鹼金屬氰化物浴池中。透過CN離子與二氧化 碳的化學反應產生碳，使碳穿過表面滲入該物內。於氣相 碳化方法中，在高溫下加熱一原料氣體以產生一碳化氣 體，且接著使碳化氣體中所含碳滲入待處理物。碳化氣體 包含例如 0.3% 的 C02、0.2% 的 CO、37.5% 的 H2、0.5% 的H20、0.2%的CH4，以及剩餘爲N2。於真空電漿碳化方 200837802 法中，首先藉一加熱器，於一真空爐中，將一待處理物加 熱至碳化溫度。接著，藉由施加數百伏特的直流電壓於二 電極間，亦即於藉爐體及一絕熱體實施之陽極與藉一待處 理物實施之陰極間，在含有諸如甲烷或丙烷之碳氫氣體之 270-400帕（2-3托）稀有氣體氛圍中產生輝光放電。由於在 輝光放電所產生的電漿氛圍中有種種電化學反應，因此， 碳氫氣體中的離子作用於待處理物的表面上，並進行碳 化。由於相較於氣相碳化方法，碳化時間短，復由於有助 • 於高濃縮碳化，又碳化程序不會於晶粒間界造成氧化，因 此，作爲冷陰極螢光燈之電極之碳化方法，真空電漿碳化 方法較氣相碳化方法有利。 上述碳化結果，於由鎳或鎳合金所形成之基材中的晶 粒間界形成鈦、錳、锆或給之碳化物或鎳-鈦、鎳-錳、鎳_ 锆或鎳-給之碳化物。 替代地，可取碳化步驟而代之，進行一氮化步驟。氮 化方法包含氣體氮化方法、鹽浴氮化方法、電漿氮化方法 # 等。於氣體氮化方法中，透過藉由以2NH3 — — 2N+ 3H2表 示的反應所造成之NH3氣體之分解，產生初生階段的氮 (N)，·並將如此獲得的氮擴散入一待氮化物中以獲得一氮化 層。於鹽浴氮化方法中，藉由將一待處理物浸漬於一主要 含有鈉或鉀氰化物及氰酸鹽之鹽浴中，氮化待處理物。使 用電漿氛圍之電漿氮化方法亦稱爲離子氮化方法。當一部 分離子化的氮於電漿氛圍中碰撞待處理物，即濺射鎳原 子。被濺射出之鎳原子與氮原子結合以形成氮化鎳，且氮 .200837802 化鎳沉積於待處理的材料上。基於與所說明真空電漿碳化 方法相同的理由，電漿氮化方法作爲氮化冷陰極螢光燈之 電極之方法最有效。 上述氮化結果，於由鎳或鎳合金所形成之基材中的晶 粒間界形成鈦、錳、锆或給之氮化物或鎳-鈦、鎳-錳、鎳-锆或鎳-飴之氮化物。 (步驟S4)將由科瓦鐵鎳鈷合金（Kovar)等製成之引線9 熔接於管狀電極7。 # (步驟S 5)將一對碳化管狀構件，亦即氣密封裝於具有 內部空間5之玻璃管2內的管狀電極7，該內部空間5充 塡至少稀有氣體及汞氣，並具有一形成於內表面4上的螢 光材料層，俾管狀電極7之開口 1 〇相互面對。 本實施例之冷陰極螢光燈亦可在可製造性上改進。管 狀電極7包含作爲基材的鎳或鎳合金，並僅包含一有限比 例的添加元素。因此，管狀電極7的熔點實質上等於鎳之 熔點（1 4 5 5 °C )，且亦接近用來作爲引線9之材料之科瓦鐵 ® 鎳鈷合金（Kovar)的熔點（ 1 5 5 0 °C )。因此，當引線9熔接並 固定於管狀電極7時，二材料均熔化至一相似程度並相互 熔融，於其間形成一合金層。以此方式，於管狀電極7與 引線9間達成牢固連接。於電極由諸如鉬或鈮之具有高熔 點之金屬製成情況下，附裝引線9的唯一方法係熔化引線 9。這經常會造成於結合力上的限制及固定程序上的限制。 本發明亦解決此問題。由於添加元素的比例減少，因此， 本實施例之冷陰極螢光燈可進一步將成本上的影響減至最 -14- 200837802 小。具體而言，由於本實施例之冷陰極螢光燈大部分由鎳 或鎳合金製成，因此，製造成本與鎳電極或鎳合金電極者 沒多大不同，從而，可提供經濟的冷陰極螢光燈。 雖然業已顯示並詳細說明本發明的某些實施例，惟須 知，在不悖離後附申請專利範圍的精神或範疇下，可進行 種種改變及修飾。 【圖式簡單說明】 第1圖係本發明冷陰極螢光燈之一例示實施例之示意 春 剖視圖； 第2圖係第1圖所示電極之放大立體圖； 第3圖係一顯示本實施例之示意金相圖；以及 第4圖一流程圖’顯示本發明冷陰極螢光燈之一例示 實施例之製造方法。 【主要元件符號說明】 1 冷陰極螢光燈 2 玻璃管 3 玻璃珠 4 內表面 5 內部空間 6 電極單元 7 管狀電極 8 底部 9 引線 10 開口 -15-。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 TECHNICAL FIELD OF THE INVENTION The present invention relates to a method for manufacturing a cold cathode fluorescent lamp and an electrode for the cold cathode fluorescent lamp. The invention also relates to a cold cathode fluorescent lamp and an electrode for the cold cathode fluorescent lamp. More particularly, the present invention relates to a method of making a tubular member for use as an electrode for a cold cathode fluorescent lamp. [Prior Art] Since the cold cathode fluorescent lamp has a potential for reduction in size, low power consumption, long life, and the like, in recent years, the situation of being used as a backlight for a liquid crystal panel or the like has been greatly increased. The cold cathode fluorescent lamp usually has a pair of electrodes disposed opposite to each other in a glass tube filled with a rare gas such as argon and mercury gas, and a structure in which a lead is connected to the electrode. Each electrode is formed into a tubular shape having a closed end and an open end. These electrodes are arranged such that the open ends are opposite each other. When a voltage is applied between the electrodes via the leads, electrons are ejected from one of the electrodes and collide with the mercury atoms to generate ultraviolet rays. The ultraviolet light is converted into visible light by a fluorescent film formed on the surface of the glass tube, and the visible light is emitted from the inside of the glass tube. Therefore, the high life of a cold cathode fluorescent lamp depends on the consumption of mercury gas. The electrodes are usually made of nickel. An example of a mixture is 99.7% nickel, 0.1% manganese, 0.1% iron, and 0.1% other impurities (carbon, bismuth, copper, sulfur). 200837802 Nickel may contain about 1% traces of cobalt. The above mixture is expressed by weight percentage. When argon gas or the like in the glass tube hits nickel, the nickel atoms are sputtered and scattered. This phenomenon is called sputtering. The scattered nickel atoms absorb mercury gas to form an amalgam, thereby reducing the effective amount of mercury gas. As a result, mercury gas is consumed, reducing the life of the cold cathode fluorescent lamp. In recent years, in order to make the life of the cold cathode fluorescent lamp longer, it is a technique to use a sputtering resistant electrode. More specifically, it has been disclosed that a tubular electrode comprising molybdenum (Mo) or niobium (Nb) has a low processing function and a high sputtering resistivity compared to nickel. For example, please refer to Japanese Patent Laid-Open No. 2002-3 5 8992 and 2003 - 1 87740. However, molybdenum and niobium are not only expensive but also have high melting points. Therefore, in order to be connected to the leads, a large amount of heat is required to melt the molybdenum or tantalum, which causes oxidation of the electrode surface. Oxidation of the electrode surface causes deterioration of sputtering resistance, which detracts from the advantage of high sputter resistance. Also, since the melting point of molybdenum or the like is greatly different from that of a lead made of Kovar or the like, it is possible that an electrode made of molybdenum or the like is substantially not melted, and charging cannot be obtained. The strength of the part combined with the wire. ♦ Japanese Laid-Open Patent Publication No. 2005-181-172 discloses a two-layer electrode having an outer layer and an inner layer disposed inside the outer layer; the outer layer is made of nickel or the like, and the inner layer is made of tungsten or molybdenum. Made of, etc., and has high sputtering resistance. The outer and inner layers are integrally formed by rolling, and then formed into a cylindrical shape, the inner layer of the crucible forms a discharge surface, and the outer layer forms a surface for connection with a lead wire. This structure achieves a satisfactory combination of the electrode and the lead while ensuring sputter resistance. However, this technique requires a large amount of high sputtering resistance and, therefore, is more disadvantageous in manufacturing cost than a nickel electrode. When a two-layer sheet is formed into a cylindrical shape by press processing in 200837802, it is often difficult to efficiently process the material of the inner layer. Japanese Laid-Open Patent Publication No. 2006-2286 No. 5, a technique for solving such problems, discloses a technique of forming an electrode comprising nickel as a substrate or an alloy thereof and containing as a additive, such as a metal of titanium. Since a metal such as titanium has a tendency to segregate in the form of an oxide between the nickel crystal grains, the bonding force at the boundary is increased, and thereby the sputtering resistance is improved. The advantage of the technique disclosed in Japanese Laid-Open Patent Publication No. 2006-22 86-15 is that an economical and good processability of nickel or a nickel alloy can be used as a substrate. However, the tubular electrode is usually formed by rolling a strip having a sheet form from an ingot of a substrate, and then forming the sheet into a tubular shape by press working. In this process, the crystal boundaries of the surface layers of the electrodes may be contaminated by the lubricating oil used during rolling and stamping. During the period in which the hermetic electrode is placed in the glass tube or during the operation of the lamp, when the temperature of the electrode portion rises, the attached oil may cause a decrease in the intergranular bonding force between the crystal boundaries. Therefore, there is a possibility that the sputtering resistance is reduced in this technique. ® In addition, in an electrode using nickel or a nickel alloy as a substrate, nickel tends to be more likely to be sputtered from the crystal boundary than the self-crystal. Therefore, there is a need to improve the sputtering resistance of the crystal boundary, although there is Japanese Patent Laid-Open Publication No. 2006-22 86 15 . SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing a cold cathode fluorescent lamp which is highly resistant to sputtering, is easy to manufacture and economical, and provides a manufacturing method for the cold cathode. The method of the electrode of a fluorescent lamp. Another object of the present invention is to provide a cold cathode fluorescent lamp which is highly resistant to sputtering, is easy to manufacture and economical, and provides an electrode for the cold cathode fluorescent lamp. According to the present invention, a method for manufacturing a cold cathode fluorescent lamp comprises the steps of: forming a material comprising nickel or a nickel alloy as a substrate and containing as an additive, manganese, zirconium or at least one or more of the elements; a tubular member closed at one end and having an opening at the other end; carbonizing the tubular member; and hermetically sealing a pair of carbonized tubular members in a glass tube, wherein the tubular electrodes are disposed therein The openings face each other, wherein the glass tube has an inner space filled with at least rare gas and mercury gas, and is provided with a layer of phosphor material formed on the inner surface of the glass tube. The metal added to the material containing nickel or a nickel alloy as a substrate tends to segregate at the crystal boundary of nickel or a nickel alloy. Therefore, by performing the carbonization step, the carbide boundary of the added element is formed in the vicinity of the surface of the tubular member. The carbides formed at the boundaries of the crystals increase the bonding force between the crystal grains and increase the surface hardness of the crystal boundaries. As a result, the sputtering resistance is improved. The oil adhering to the tubular member is effectively removed by the carbonization step during the step of forming the material into a tubular member. Therefore, the reduction of the residual oil may cause deterioration of the sputtering resistance at the crystal boundary. According to another exemplary aspect of the invention, a nitriding step comprising a tubular member is substituted for the carbonization step. Since the nitrogen formed at the intercrystalline boundary increases the bonding force between the crystal grains and increases the surface hardness of the crystal boundary, and since the residual oil is removed by the nitriding step, the same effect as that achievable by the carbonization step can be attained. 200837802 As described above, the present invention provides a method for manufacturing a cold cathode fluorescent lamp which is highly resistant to sputtering, is easy to manufacture and economical, and an electrode for manufacturing the cold cathode fluorescent lamp The method. The present invention also provides a cold cathode fluorescent lamp which is highly resistant to sputtering, is easy to manufacture and economical, and an electrode for the cold cathode fluorescent lamp. The above and other objects, features and advantages of the present invention will become apparent from the accompanying drawings. [Embodiment] φ First, a cold cathode fluorescent lamp and an electrode according to an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings. According to the present invention, a cold cathode fluorescent lamp is suitable for use as a backlight of a liquid crystal panel. However, cold cathode fluorescent lamps can also be used for other purposes. Fig. 1 is a schematic cross-sectional view showing the configuration of an exemplary embodiment of a cold cathode fluorescent lamp. The cold cathode fluorescent lamp 1 has a glass tube 2 formed of borosilicate glass. Both ends of the glass tube 2 are hermetically sealed by a sealing glass (glass beads 3). The glass tube 2 has an outer diameter of 1.5 to 6.0 mm, and preferably has an outer diameter of 1.5 to 5.0 mm. The material of the glass tube 2 may also be lead glass, soda glass, low lead glass, or the like. A layer of phosphor material not shown is formed on the inner surface 4 of the glass tube 2 over the entire length of the tube. The phosphor material forming the layer of phosphor material may be selected from existing or novel phosphor materials such as halophosphate fluorescent materials and rare earth fluorescent materials depending on the use and use of the cold cathode fluorescent lamp 1. Further, the phosphor layer may be formed of a phosphor material prepared by mixing two or more kinds of phosphor materials. A predetermined amount of a rare gas such as argon, helium or neon and a predetermined amount of mercury of 200837802 are filled in the inner space 5 surrounded by the inner surface 4 of the glass tube 2 and the internal pressure is reduced to about tenths An atmospheric pressure. A pair of electrode units 6 are provided at both ends of the glass tube 2 in the longitudinal direction. Each of the electrode units 6 is composed of a tubular electrode 7 and a lead 9 connected to the bottom portion 8, which is a closed end of the tubular electrode 7. The tubular electrode 7 in each electrode unit 6 is located inwardly from the inner space 5 end of the glass tube 2, and the opening 10 of one of the tubular electrodes 7 faces the other opening 10. One end of each lead 9 is welded to the bottom 8 of the corresponding tubular electrode 7, and the other end is extended outside the glass tube 2 through the glass beads 3. The lead 9 is made of a conductive material such as Kovar. Fig. 2 is a plan view showing the arrangement of the electrode unit 6 of the cold cathode fluorescent lamp 1. The tubular electrode '7' constituting the electrode unit 6 has a tubular portion 23. One end of the tubular portion 23 is provided with an opening i 相对 with respect to the longitudinal direction, and the other end is closed by the bottom portion 8. The lead 9 is welded to the bottom of the tubular electrode 7 with the end face 1 2 〇 The tubular electrode 7 contains nickel or a nickel alloy as a substrate. Mainly in the tubular • The surface of the electrode 7 forms titanium, manganese, zirconium or a carbide or nitride. Carbides or nitrides, although formed in the nickel grains, are mainly formed in the grain boundaries. Two or more elements may be contained between titanium, tantalum, zirconium or lead. The proportion of titanium in the mixture is preferably from 009 to 8% by weight. The ratio of chromium to the mixture is preferably from 0 · 〇 5 to 1 _ 1 w t % (weight percent). The ratio in the mixture is preferably from 1 · 1 to 4 · 〇 w t % (% by weight). The upper limit of each element in the mixture is mainly dependent on the manufacturability of the tubular electrode 7. The right ratio is 13⁄4 at the upper limit, and the material becomes too hard to be borrowed. -10- 200837802 A cylindrical shape is formed by press working. The lower limit of the proportion of each element in the mixture is determined to ensure sufficient high sputter resistance. An example of a mixture containing titanium as a main additive comprises 99.7% nickel, 0.05% titanium, 0.15% manganese, and 1% other impurities (carbon, ruthenium, copper, sulfur, manganese, and iron). Nickel contains a cobalt equivalent to about 1% trace of 〇·〇. Titanium is present in the form of titanium carbide or nickel-titanium carbide. The reason why the sputtering resistance of the tubular electrode 7 is improved by adding these metals will be explained with reference to Fig. 3. Although the case of adding titanium is explained, the explanation of φ is equally applicable to the case of adding manganese, zirconium or giving. Nickel or a nickel alloy usually has a polycrystalline structure, and a grain boundary B is formed at an interface between the crystal grains G. Since the bonding force between the crystal grains is small, the grain boundary B is easily affected by sputtering. Sputtering mainly occurs at the grain boundary B and gradually expands into the grain G. On the other hand, the additive added to nickel tends to segregate at the grain boundary B, and titanium is no exception. If titanium is carbonized or nitrided when the grain boundary B is sufficiently segregated, the titanium present in the grain boundary B is formed as a carbide or nitride of titanium or a carbide or nitride of nickel-titanium. These carbides or nitrides generally function to greatly increase the interfacial bonding force and thereby function to increase the surface hardness of the material. Therefore, it is more resistant to service. The lower ratio of the proportion of the elements in the above mixture corresponds to the amount of titanium required to distribute the sufficient amount of titanium to the grain boundary B to improve the sputtering resistance. A method of manufacturing the above-described cold cathode fluorescent lamp will be described with reference to Fig. 4. (Step S1) First, nickel or a nickel alloy is melted, followed by addition of titanium, manganese, chromium or (hereinafter referred to as ~addition element yttrium). Next, the nickel or nickel alloy is cured -11-200837802 to form an ingot containing the added element. Since the substrate formed of nickel or a nickel alloy has a polycrystalline structure as described above, the additive element is deviated at the grain boundary. Although a part of the added element is combined with oxygen contained in nickel or the atmosphere and exists in the form of an oxide, it is considered that not all of the elements of the added element are oxidized, and most of the added elements are not oxidized. (Step S2) The ingot is formed into a thin plate (belt) in a normal rolling step. The sheet is then subjected to stamping and formed into a tubular member which is closed at one end and open at the other end. In these steps, oil is used as the φ lubricant. Although the oil is removed by washing, as mentioned above, some of the oil may mainly remain in the grain boundaries and may cause a decrease in the bonding force of the particles at the grain boundaries. The obtained tubular member has the same shape as the tubular electrode 7 shown in Figs. 1 and 2, but differs from the tubular electrode 7 in that it is not subjected to the carbonization or nitridation procedure described below. (Step S3) Next, the formed tubular member is carbonized. The carbonization method includes a solid phase carbonization method, a liquid phase carbonization method, a gas phase carbonization method, a vacuum plasma carbonization method, and the like. In the solid phase carbonization process, a # carbon monoxide (CO) is produced in a carbonization tank. The CO is then decomposed on the surface of a material to be treated, allowing carbon (C) to penetrate and diffuse into the material. In the liquid phase carbonization process, a to-be-treated material is immersed in an alkali metal cyanide bath. Carbon is generated by a chemical reaction of CN ions with carbon dioxide, allowing carbon to penetrate into the object through the surface. In the gas phase carbonization method, a raw material gas is heated at a high temperature to produce a carbonized gas, and then carbon contained in the carbonized gas is infiltrated into the object to be treated. The carbonized gas contains, for example, 0.3% C02, 0.2% CO, 37.5% H2, 0.5% H20, 0.2% CH4, and the remainder N2. In the vacuum plasma carbonization method 200837802, a treatment is first heated to a carbonization temperature by a heater in a vacuum furnace. Then, by applying a direct current voltage of several hundred volts between the two electrodes, that is, between the anode implemented by the furnace body and a heat insulator and the cathode implemented by the object to be treated, the hydrocarbon gas containing methane or propane is contained therein. A glow discharge occurs in a rare gas atmosphere of 270-400 Pa (2-3 Torr). Since there are various electrochemical reactions in the plasma atmosphere generated by the glow discharge, ions in the hydrocarbon gas act on the surface of the object to be treated and carbonize. Since the carbonization time is shorter than that of the gas phase carbonization method, the carbonization process is not affected by the high concentration carbonization, and the carbonization process does not cause oxidation at the grain boundary. Therefore, as a carbonization method of the electrode of the cold cathode fluorescent lamp, The vacuum plasma carbonization process is advantageous over the gas phase carbonization process. The above carbonization results in the formation of titanium, manganese, zirconium or a carbide or nickel-titanium, nickel-manganese, nickel-zirconium or nickel-carbonized in the grain boundaries in a substrate formed of nickel or a nickel alloy. Things. Alternatively, a carbonization step can be taken instead of a nitridation step. The nitriding method includes a gas nitriding method, a salt bath nitriding method, a plasma nitriding method #, and the like. In the gas nitriding method, the nitrogen (N) in the primary stage is generated by the decomposition of the NH3 gas caused by the reaction represented by 2NH3 - 2N + 3H2, and the nitrogen thus obtained is diffused into a to-be-nitride. A nitride layer is obtained. In the salt bath nitriding method, the object to be treated is nitrided by immersing a material to be treated in a salt bath mainly containing sodium or potassium cyanide and cyanate. The plasma nitridation method using a plasma atmosphere is also called an ion nitridation method. When a portion of the ionized nitrogen collides with the object to be treated in a plasma atmosphere, the nickel atom is sputtered. The sputtered nickel atoms combine with nitrogen atoms to form nickel nitride, and nitrogen. 200837802 nickel is deposited on the material to be treated. The plasma nitridation method is most effective as a method of nitriding the electrode of a cold cathode fluorescent lamp for the same reason as the vacuum plasma carbonization method described. The above nitridation results in the formation of titanium, manganese, zirconium or a nitride or nickel-titanium, nickel-manganese, nickel-zirconium or nickel-bismuth in the grain boundaries in a substrate formed of nickel or a nickel alloy. nitride. (Step S4) A lead 9 made of Kovar or the like is welded to the tubular electrode 7. # (Step S5) A pair of carbonized tubular members, that is, hermetically sealed, are mounted in the tubular electrode 7 in the glass tube 2 having the internal space 5, the internal space 5 being filled with at least a rare gas and mercury gas, and having a formation On the inner surface 4, the phosphor material layer, the opening 1 of the crucible electrode 7, faces each other. The cold cathode fluorescent lamp of this embodiment can also be improved in manufacturability. The tubular electrode 7 contains nickel or a nickel alloy as a substrate and contains only a limited proportion of additive elements. Therefore, the melting point of the tubular electrode 7 is substantially equal to the melting point of nickel (1 4 5 5 ° C), and is also close to the melting point of Kovar which is used as the material of the lead 9 (1 5 5 0 °C). Therefore, when the lead 9 is welded and fixed to the tubular electrode 7, both materials are melted to a similar degree and melted with each other to form an alloy layer therebetween. In this way, a firm connection is made between the tubular electrode 7 and the lead 9. In the case where the electrode is made of a metal having a high melting point such as molybdenum or tantalum, the only method of attaching the lead 9 is to melt the lead 9. This often results in limitations in binding forces and limitations on fixed procedures. The present invention also solves this problem. Since the proportion of the added elements is reduced, the cold cathode fluorescent lamp of this embodiment can further reduce the cost impact to the most -14-200837802. In particular, since the cold cathode fluorescent lamp of the present embodiment is mostly made of nickel or a nickel alloy, the manufacturing cost is not much different from that of the nickel electrode or the nickel alloy electrode, thereby providing economical cold cathode fluorescent light. light. While certain embodiments of the present invention have been shown and described, it will be understood that various changes and modifications may be made without departing from the scope of the invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic cross-sectional view showing an exemplary embodiment of a cold cathode fluorescent lamp of the present invention; FIG. 2 is an enlarged perspective view of the electrode shown in FIG. 1; The schematic metallographic diagram of FIG. 4 and the flow chart of FIG. 4 show a manufacturing method of an exemplary embodiment of the cold cathode fluorescent lamp of the present invention. [Main component symbol description] 1 Cold cathode fluorescent lamp 2 Glass tube 3 Glass beads 4 Inner surface 5 Internal space 6 Electrode unit 7 Tubular electrode 8 Bottom 9 Lead 10 Opening -15-