201106412 六、發明說明： 【發明所屬之技術領域】 本發明係關於一種冷陰極螢光燈，特別關於一種照明 用冷陰極螢光燈。 【先前技術】 冷陰極螢光燈（Cold Cathode Fluorescent Lamp， CCFL)為一種汞放電燈，在通過高頻高壓的交流電後，燈 管内部的電子撞擊汞蒸氣原子使其達到激發態（Excited State)，被激發的汞原子會以放射紫外光的方式回到基態 (Ground State)，而所放射之紫外光會進一步激發冷陰極 螢光燈中的螢光體’以產生可見光。 目前常見之冷陰極營光燈管的内徑大多分佈在14〜 2/随間，而這些屬於小管徑之CCFL，其電極之電子發 射面積亦較小，導致該些燈管 " 態下，會因電極發射電流及電極電流錄 造成燈管之管電流過飽和，也就 比過南而 射面積所能負荷的能力。在此種‘過電极電子發 耗功率變高，但過多的功率肖耗；CCFL的消 光。為了得到較高的操作功广上都轉換成熱而不是 採用較大内#之冷陰極榮脉=同時維持良好的效率， 出一個適合大内徑CCFL·之齋疋有必要的，並且同時找 面積之比是現今極切需要突破電流與電極電子發射 201106412 【發明内容】 有鑑於上述課題，本發明之目的為提供一種合適大管 徑之冷陰極螢光燈使用之電極發射電流及電極電子發射 面積之比，以提升冷陰極螢光燈之功率及發光效率。 為達上述目的，依據本發明之一種照明用冷陰極螢光 燈包含一冷陰極螢光燈管以及一驅動單元。冷陰極螢光燈 管之内管直徑介於2.5mm〜30mm之間，其二端各具有一 電極，且冷陰極螢光燈管之電極發射電流與電極電子發射 面積之比係介於1 .OmA/mm2〜10 mA/mm2之間。驅動單元 與冷陰極螢光燈管之電極電性連接。 承上所述，本發明提供一種大管徑之冷陰極螢光燈 管，其内管直徑介於2.5mm〜30mm之間，故其電極面積 可大幅增加而能容許較高的管電流。經由實驗證實，本發 明找出合適的電極發射電流與電極電子發射面積之比大 於1.0mA/mm2時，可使冷陰極螢光燈開始達到高功率，而 電極發射電流與電極電子發射面積之比小於1 〇 mA/mm2 時，可避免冷陰極螢光燈管造成管電流過飽和，進而避免 部分功率轉成熱，以提升發光效率。 【實施方式】 以下將參照相關圖式，說明依本發明較佳實施例之一 種照明用冷陰極螢光燈。 如圖1所示，本發明較佳實施例之照明用冷陰極螢光 燈1係包含一冷陰極螢光燈管11以及一驅動單元12。 201106412 ▲古月不限制冷陰極螢光燈管11之型態，其可例如 馮罝官、或XJ怂 螺旋管，於此I、或C管、或環形管、或單螺旋管、或雙 包含-管體Ul、M直管為例作說明。冷陰極榮光燈管11 〜30mm之間U ’管體111之内管直徑D1係介於2.5麵 例之内管直二，其屬於大管徑之冷陰極螢光燈管。本實施 € D1係以3mm為例。 冷陰極螢井权一 不限制電核=管11之二端各具有一電極112。本發明 形或杯狀等等，、、形狀’其可例如為直條形、圓形、擴圓 在本實施例中’於此係以直條形為例，且其剖面為圓形。 極電子發射面社冷陰極榮光趣管11之電極發射電流與電 間。其中，貝之比係介於UmA/m1112〜1〇 mA/mm2之 例中電極發電流即所謂的「管電流」，在本實施 面積係以電極' A〜12mA為例。電極電子發射 直徑D2 A 9 <之剖面面積來作為計算值，電極112之 以馬2.6mm (半押為j q 、 發射電流為llmA，電極U2 _)°故以本實施例中電極 得到電極為1·3ππη來計算，可 11 /(π*1 3*1 ^ 〇 η七射面積之比如下： (π 1·3”.3卜 2.07(mAW) 卜，在其他實施例可計复山甘 直輕為2.1mm(半徑為1〇5切〃他值。例如若以電極 來計算時（計算公式同上），:’電極發射電流為8mA 射面積之比約為2.31 (mA/miJ極^電流與電極電子發 (半徑為1.85_)，電極發射電产電極直徑為3.7_ 本發射電流與電極電子發射面^比誕來計算時，電 约為 2.5( mA/mm2)。 201106412 經由數次實驗證實，未聲明找出合適 與電極電子發射面積之比大*1〇一2 == 高功率(例如大於游4==功率開始達到 極發射電流與電極電子發射 面積之比小於1G mA/mm _ ’可㈣冷陰極鸯光燈管n 之管電流減過飽和，進，免部㈣率消耗轉成^，以 提升發光效率。 冷陰極螢光燈管 氬、氖）封入其内， u更具有少量惰性氣體114 (例如 而封入惰性氣體之氣壓介於lt〇rr〜 1 OOtorr之間。此種低壓之環境有助於電極發射電流與電極 電子發射面積之比的提升，進而提升發光效率。 另外，本實施例之電極112材料可使用耐離子森擊材 料’例如鎢、鉬、鈮、鎳或其合金。由於冷陰趣榮光燈管 11内之電漿離子會轟擊電極112而損耗電極，轉由对離子 轟擊材料可容許更高的電極發射電流與電極電子發射面 積之比’進而提升發光效率。在本實施例中，電極112是 藉由粉末冶金製程而形成。 驅動單元12係與冷陰極螢光燈管11之電挺112電性 連接，以驅動冷陰極螢光燈管11發光。驅動單元12可包 含換流電路（inverter)以提供高壓之交流電。驅動單元 12可以單邊驅動方式驅動冷陰極螢光燈管n，咬是以雙 邊驅動方式驅動冷陰極螢光燈管11，於此係以雙邊驅動方 式為例。 綜上所述，本發明提供一種大管徑之冷陰極螢光燈 201106412 管，其内管直徑介於2.5mm〜30mm之間，故其電極面積 可大幅增加而能容許較高的管電流。經由實驗證實，本發 明找出合適的電極發射電流與電極電子發射面積之比大 於1.0mA/mm2時，可使冷陰極螢光燈開始達到高功率，而 電極發射電流與電極電子發射面積之比小於10. mA/mm2 時，可避免冷陰極螢光燈管造成過飽和，進而避免部分功 率轉成熱而非光以提升發光效率。 以上所述僅為舉例性，而非為限制性者。任何未脫離 本發明之精神與範疇，而對其進行之等效修改或變更，均 應包含於後附之申請專利範圍中。 【圖式簡單說明】 圖1為本發明較佳實施例之一種照明用冷陰極螢光燈 的示意圖。 【主要元件符號說明】 I :冷陰極螢光燈 II :冷陰極螢光燈管 III :管體 112 :電極 113 :螢光體 114 :惰性氣體 12 :驅動單元 D1 :内管直徑 201106412 D2 :電極直徑201106412 VI. Description of the Invention: [Technical Field] The present invention relates to a cold cathode fluorescent lamp, and more particularly to a cold cathode fluorescent lamp for illumination. [Previous Technology] Cold Cathode Fluorescent Lamp (CCFL) is a mercury discharge lamp. After passing through high frequency and high voltage alternating current, electrons inside the tube collide with mercury vapor atoms to reach an excited state. The excited mercury atoms return to the ground state by emitting ultraviolet light, and the emitted ultraviolet light further excites the phosphor in the cold cathode fluorescent lamp to generate visible light. At present, the inner diameters of the common cold cathode camping lamps are mostly distributed in 14~2/room, and these are CCFLs with small diameters, and the electron emission area of the electrodes is also small, resulting in the states of the lamps. Because of the electrode emission current and the electrode current recording, the tube current over-saturation of the tube is more than the capacity of the shot area. In this kind of 'over-electrode electron power consumption becomes high, but excessive power consumption; CCFL extinction. In order to obtain higher operating power, it is converted into heat instead of using a larger internal cold cathode yin = while maintaining good efficiency. It is necessary to prepare a large inner diameter CCFL. The area ratio is the current need for breakthrough current and electrode electron emission 201106412. SUMMARY OF THE INVENTION In view of the above problems, the object of the present invention is to provide an electrode emission current and electrode electron emission for a cold cathode fluorescent lamp of a suitable large diameter. The ratio of the area to improve the power and luminous efficiency of the cold cathode fluorescent lamp. To achieve the above object, a cold cathode fluorescent lamp for illumination according to the present invention comprises a cold cathode fluorescent lamp and a driving unit. The inner diameter of the cold cathode fluorescent lamp tube is between 2.5 mm and 30 mm, and each of the two ends has an electrode, and the ratio of the electrode emission current of the cold cathode fluorescent lamp to the electron emission area of the electrode is 1. OmA/mm2~10 mA/mm2. The driving unit is electrically connected to the electrode of the cold cathode fluorescent lamp. In view of the above, the present invention provides a large-caliber cold cathode fluorescent lamp having an inner tube diameter of between 2.5 mm and 30 mm, so that the electrode area can be greatly increased to allow a higher tube current. It has been experimentally confirmed that the present invention finds that the ratio of the electrode emission current to the electron emission area of the electrode is greater than 1.0 mA/mm 2 , so that the cold cathode fluorescent lamp can start to reach high power, and the ratio of the electrode emission current to the electrode electron emission area. When less than 1 〇 mA/mm2, the tube current supersaturation caused by the cold cathode fluorescent tube can be avoided, and part of the power can be prevented from being converted into heat to improve the luminous efficiency. [Embodiment] Hereinafter, a cold cathode fluorescent lamp for illumination according to a preferred embodiment of the present invention will be described with reference to the related drawings. As shown in Fig. 1, a cold cathode fluorescent lamp 1 for illumination according to a preferred embodiment of the present invention comprises a cold cathode fluorescent lamp tube 11 and a driving unit 12. 201106412 ▲The ancient moon is not limited to the type of refrigeration cathode fluorescent tube 11, which can be, for example, Feng Yuguan, or XJ怂 spiral tube, here I, or C tube, or ring tube, or single spiral tube, or double inclusion tube The body Ul, M straight tube is taken as an example for illustration. The cold cathode glory lamp is between 11 and 30 mm. The inner tube diameter D1 of the U' tube body 111 is between 2.5 and 2, which is a cold cathode fluorescent tube with a large diameter. This implementation of the € D1 is based on 3mm. The cold cathode fluorescing right does not limit the nucleus = each end of the tube 11 has an electrode 112. The present invention has a shape or a cup shape, etc., and the shape ' can be, for example, a straight strip shape, a circular shape, or a rounded shape. In the present embodiment, the straight strip shape is taken as an example, and the cross section thereof is circular. The electrode of the cold electron emitting surface of the cold cathode glory tube 11 emits current and electricity. Among them, the ratio of the shell to the UmA/m1112 to 1 mA/mm2 is the so-called "tube current", and the area of the present embodiment is the electrode 'A to 12 mA. The cross-sectional area of the electrode electron emission diameter D2 A 9 < is used as the calculated value, and the electrode 112 is 2.6 mm (the half-buck is jq, the emission current is llmA, the electrode U2 _). Therefore, the electrode obtained in the present embodiment is the electrode. Calculated by 1·3ππη, 11 / (π * 1 3 * 1 ^ 〇 η seventh shot area as follows: (π 1 · 3". 3 Bu 2.07 (mAW) Bu, in other embodiments can be calculated The straight light is 2.1mm (the radius is 1〇5 and the value is 。5. For example, if the electrode is used for calculation (the calculation formula is the same as above), the ratio of the electrode emission current is 8mA to the shot area is about 2.31 (mA/miJ pole ^ current) With the electrode electron emission (radius 1.85_), the electrode emission power electrode diameter is 3.7_, the emission current is calculated from the electrode electron emission surface, and the electricity is about 2.5 (mA/mm2). 201106412 Through several experiments It is confirmed that it is not stated that the ratio of the electrode to the electron emission area of the electrode is large*1〇2 == high power (for example, greater than the ratio of the peak emission current to the electron emission area of the electrode 4 == power is less than 1G mA/mm _ 'Can (4) cold cathode neon tube n tube current reduced over saturation, into, free part (four) rate consumption into ^, to improve Light efficiency. Cold cathode fluorescent tube argon, helium) is enclosed, u has a small amount of inert gas 114 (for example, the pressure of the inert gas is between lt〇rr~1 OOtorr. This low pressure environment helps The ratio of the electrode emission current to the electron emission area of the electrode is increased, thereby improving the luminous efficiency. In addition, the material of the electrode 112 of the embodiment may use an ion-resistant material such as tungsten, molybdenum, niobium, nickel or an alloy thereof. The plasma ions in the glory lamp 11 will bombard the electrode 112 and lose the electrode, and the ion bombardment material can allow a higher ratio of the electrode emission current to the electron emission area of the electrode, thereby improving the luminous efficiency. The electrode 112 is formed by a powder metallurgy process. The driving unit 12 is electrically connected to the battery 112 of the cold cathode fluorescent lamp tube 11 to drive the cold cathode fluorescent lamp 11 to emit light. The driving unit 12 can be replaced. An inverter is provided to provide high-voltage alternating current. The driving unit 12 can drive the cold cathode fluorescent lamp n by a single-side driving method, and the bite is driven by a bilateral driving method to the cold cathode fluorescent lamp. The tube 11 is exemplified by a bilateral driving method. In summary, the present invention provides a large-diameter cold cathode fluorescent lamp 201106412, the inner tube diameter of which is between 2.5 mm and 30 mm, so the electrode thereof The area can be greatly increased to allow a higher tube current. It has been experimentally confirmed that the present invention can find that a suitable ratio of the electrode emission current to the electrode electron emission area is greater than 1.0 mA/mm2, so that the cold cathode fluorescent lamp can start to reach a high level. Power, and the ratio of the electrode emission current to the electron emission area of the electrode is less than 10. mA/mm2, which can avoid over-saturation of the cold cathode fluorescent tube, thereby preventing some of the power from being converted into heat instead of light to improve the luminous efficiency. The above is intended to be illustrative only and not limiting. Any equivalent modifications or alterations to the spirit and scope of the present invention are intended to be included in the scope of the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic view of a cold cathode fluorescent lamp for illumination according to a preferred embodiment of the present invention. [Description of main component symbols] I: Cold cathode fluorescent lamp II: Cold cathode fluorescent lamp III: Tube 112: Electrode 113: Phosphor 114: Inert gas 12: Drive unit D1: Inner tube diameter 201106412 D2: Electrode diameter