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  • The cold cathode fluorescent lamp(CCFL) is a core component of information display\equipment such as notebook computers, PDAs, LCD monitors, LCD TVs,and digital cameras.

    CCFL’s Strengths:Thin Tube Diameter, Light Weight, and Proven Performance

    Characteristics of a CCFL.
    A CCFL is made by applying a fluorescent material inside a glass tube, inserting and sealing noble gas and mercury in the tube, and attaching electrodes at the ends of the tube. By applying 15,000~18,000 V of high voltage to both ends of the tube, the electrodes inside it move to both ends at high speed, and the secondary electron produces a discharge from the crash between the electrodes and the electrons. The electrons produced from the electrodes crash with the mercury atoms inside the tube, producing a 253.7-m ultraviolet ray. This is based on the principle that a visible ray is emitted as an ultraviolet ray crashes with a fluorescent object, as that applied on the inner side of the glass tube. A CCFL works with a small electric current, has a small caloric value, and has long life. By adjusting the combination ratio of the fluorescent substance spread inside the glass tube, various colors can be displayed. The diameter of the lamp is about 1.8~4.0 mm and its length can be made to reach up to 1,300 mm. The most popular types of CCFL are the line type, the L type, the ㄷ type, and the round type. Its acceptable temperature range is 0~80°C and its humidity is 5~85%.

    A Primary Factor to Decide Its Brightness and Lifespan
    Since a CCFL is operated by a high-voltage direct current, an inverter changes alternating current into direct current. This inverter has an important effect on the lamp and its entire performance. Hwang, Jae Sung, deputy general manager of the light equipment inverter development team of Keumho Electric, Inc., explained, “If 10 mm of the length of a lamp is changed, its inverter generating power should also be adjusted. The brightness and life of the lamp depend on the accurate control of its generating power.” The inverter generating power of a light panel is as important as that of an LCD monitor because it is directly connected to the brightness, color temperature, and life of the lamp. The basic procedure behind the accurate control of generating power is to set the inverter generating power to the appropriate length of the lamp that clearly stated by the CCFL manufacturer. If this is ignored, heat can be generated from the inverter or the lamp’s interior parts can be burned. In particular, if an unsuitable lamp length and inverter generating power are let alone since no problem occurs in the initial stage, the brightness of the lamp can suddenly diminish.

    Different CCFL Light Panels Available in The Market
    The core components of a light panel are the lamp, the reflector, which helps to efficiently collect light and centralize it in one direction from the lamp, and the light guide plate (LGP) that makes the line-type source of light a plane-type source of light on the whole image display plane. According to the size and purpose of its light panel, a CCFL as well as a T5 and an EEFL, etc., are used as the inner source of light. LGP is the part that processes a special pattern on the transparent acrylic panel such as a dot pattern, a scratch pattern, and a 3D-V cutting pattern, etc. No matter what the pattern, though, they all evenly spread the light. There are different types of CCFL light panels such as the continuous type, the flickering type, the color-changing type, and the fluorescent pen type, among others. The color-changing type can better enhance the level of attention, as it changes colors. The fluorescent-pen-type light panel is the product of the so-called menu board that is popular in coffee shops, bakeries, and cafes, etc., due to its various unique expressions and colors. It can also be classified into the front-opening and -closing type and the rear-opening and -closing type, according to its opening and closing style. The front-opening and -closing style is mainly used these days for the easy replacement of advertisements and due to the convenient maintenance. CCFLs are popularly used as the source of light of light panels because its life is more than 5 times longer than that of a general fluorescent lamp, making it easier to maintain, and since the thickness of its tube is 1/10 that of the general fluorescent lamp, making it easy to change its size and its panel.

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